hacker news with inline top comments    .. more ..    31 Jul 2014 News
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Propeller acquired by Palantir
17 points by Jarred  1 hour ago   5 comments top 3
ianlevesque 1 minute ago 0 replies      
I don't have any problem with the acquisition but it seems like every single one of these inevitably includes "It's been an incredible journey" in their message. Surely people can be a bit more creative with the phrasing.
greghinch 27 minutes ago 1 reply      
Can anyone chime in as to what Propeller does (did)? Looks like they shut down the site as part of this? (probably an aqui-hire?)
bane 1 hour ago 1 reply      
Looks like Palantir is on an acquisition spree


Let's Build a Traditional City and Make a Profit
151 points by Mz  8 hours ago   92 comments top 20
rdtsc 5 hours ago 12 replies      
This might sound very un-enlightening, offensive or jarring to many in this forum, but I actually like my suburban living. I'll be first to admit it is selfish, wasteful to environment (I am watering my plants and grass and mowing it). But when I wanted to buy a home I wanted a home in the suburbs with trees and wide roads and cul-de-sacs and playgrounds and pool and close to work (10min, by car, 30 by bicycle). It is one of those elements that when it came time to put the money on the table I made the decision I would have probably "preached" against in a group of peers. That probably happens often (people say they want green but end up buying an SUV instead of a Prius).

This is probably sounding very wrong and boring to many people here who extol city living, enjoy the energy and vitality of the bustling city center. Public transportation, walk-able streets, stores, clubs, coffee shops, restaurants. But I would like that on vacation only for about a week or so. Then I want to go back to my boring suburban home with grass, trees an flowers around.

See, I grew up in a city and experienced that. And it was ok. But I like this better. I wonder if there is an element of that -- rejecting the places we grew up and deciding the opposite environment is better for it. I imagine a lot of people in US grew up in the suburbs and many now feel attracted to the city.

bokonist 5 hours ago 4 replies      
I love the idea of building a city as a startup, and competing with other cities by being a superior product.

However, my vision for the perfect city is quite different than OP's.

My ideal city:

* Density is between 5k-8k per square mile (twice as dense as Palo Alto, half as dense as Cambridge, MA)

* The density and layout should support a high walkability index. There should be a grocery store, barber, coffeeshop, pharmacy, etc, within a half-mile to a mile of most housing.

* Housing arranged in blocks, with a shared yard for all people on the block. So each house would have a small patio owned by the home owner. Behind that would be a collective yard/green area shared by all the neighbors on the block. This shared area might have a basketball hoop, swimming pool, jungle-gym, soccer nets, BBQ pit or whatever the residents wanted. It would be behind all the housing, and thus insulated from the city. The block should be small enough that pretty much any parent can look out their window and see their kids playing. Basically, any parent should feel perfectly safe just letting their five-year old kid play outside in the common backyard with other kids.

* The road system should be optimized around bicycles, scooters, and microcars (like the Carver or Automoto, because bicycles are not so good for older people in the winter). Roads would have two narrow lanes in each direction, a left-hand lane for 25MPH scooters and roadbikes, and a right-hand lane for slower bicycles and roller bladers. Cars would only be allowed on main arterials, driving a car on the bike roads would require a $10 per day special pass. Optimizing around bikes and mini-vehicles allows for getting between point A & B very quickly, but limits congestion, pollution, and the expense of a full-sized car.

Things I don't like about OP's dream:

* it feels to claustrophobic. I like green space.

* walking is just much slower than biking, so I prefer biking.

* it is really not pleasant to have both bikes and mopeds using the same narrow streets. One of the least pleasant aspects of traveling in a a classical city core is having the mopeds buzz by you at 20MPH.

* row housing looks nice from the outside, but severely limits the amount of sunlight coming inside. I greatly prefer standalone units that have windows on all four-sides.

* In general, I think that very dense, old school cities can be more pleasant to visit for a little while, than to actually live in long term. There is a reason why most people in those countries do not wish to live in such housing or build more housing like it.

The biggest problem in general with doing a city-as-a-startup is jobs. Due to the winner-takes-all nature of the economy, the highest paying jobs are concentrated in a few metro areas where the big winning companies reside. I'm not sure how you bootstrap the economy of the new city.

cjoh 4 hours ago 5 replies      
I live in a community called Serenbe. (http://serenbe.com) which has taken a much different approach to suburban new urbanist development. It's built around an organic farm rather than a golf course, it's got miles of green space and trails, and a fantastic commitment to ecology and the environment -- for example the outdoor irrigation system is built from gray water from the homes in the community.

Also: it's got some great restaurants and about 80% of my diet comes from food that's made within 25 miles of where I live now. To get to a restaurant, we take a brief stroll through the woods.

Smartest thing I ever did was move here. I've spent my whole life trying to work with governments (mostly federal) to use technology to improve service delivery and if I'm honest with myself, it's been mostly discouraging. But since I've moved here, I've met with the mayor and we're beginning to do amazing things.

What makes an amazing place to live, though isn't the lack of automobiles (as the author of this post seems to believe), or great architecture -- but rather an attitude of community. That you all have a shared role in the success of each other's life environment. Human beings are wired for that, and both urban and suburban environments tend to separate us from that.

femto 5 hours ago 3 replies      
If you want to found a city, here's a suggestion for its location. It's a crazy pipe dream but here goes: build a city next door to Sydney, Australia, on the other side of the Great Dividing Range.

Background: Sydney is a well developed city with a population of 4.5 million. It is built on a coastal basin, bounded by the Pacific ocean on the east, a mountain range (Great Dividing Range) on the west, a river/green belt on the north and national parks on the south, with expansion happening in a south-west direction. Real estate prices are high compared most other cities. To the west of the Great Dividing Range is the beginning of the flat interior of Australia. The first significant town to the west of the Great Dividing Range is Lithgow.

Running east to west, the Great Dividing range is delineated by a steep climb at the suburb of Glenbrook, and a steep descent at Mount Victoria. There is a winding highway and railway connecting these two points, so the trip from Lithgow to Sydney is slow. As the crow flies, the distance between Glenbrook and Mount Victoria is about 45km.

The plan would be to build a tunnel under the Great Dividing Range, install a high speed train in it, and cut the travel time between Sydney and the west of the range to minutes. Tunnels longer than 45km exist today, so it should be doable from a technical standpoint. The project could be paid for by the increase in land value to the west of the range.

As an aside, there are ongoing proposals for a high speed train (HST) along the eastern seaboard of Australia, linking Melbourne, Canberra, Sydney and Brisbane, all major cities. The seaboard is rugged and heavily populated, so some proposals have the HST to the west of the Dividing Range. A new city, to the west of the divide, could act as a junction between a north-south HST and a connection to Sydney, providing a ready made economy.

austinz 6 hours ago 3 replies      
I wish someone would make a serious successor to SimCity - an actual simulator that modeled theories from the field of urban planning and allowed people to experiment with different layouts, policies, etc. This would be a very different piece of software from the vanity building placing games on the market today, and something much more in line with Will Wright's original vision.
tempestn 56 minutes ago 0 replies      
If we wanted to build the ideal city and cost weren't a concern, we could really expand on the use of underground for transportation. The best cities for humans tend to have great subway systems, but in theory we could do a lot more. Basically all parking and most arterial roads could be underground, leaving above-ground an almost-entirely pedestrian paradise. Sure, driving in an endless tunnel doesn't sound terribly pleasant, but the idea is to get people from A to B efficiently, then out of the car. Unfortunately building this kind of infrastructure under existing cities would be prohibitively expensive.

Under a new town you might be able to do it much more cheaply (which isn't to say cheaply in an absolute sense), but of course the economic incentive isn't there at that point.

That said, with services like Uber, and much more so, driverless vehicles, hopefully the desire to bring a car along wherever we go will begin to ebb in the near future, making the narrow street vision described here much less of a compromise. I imagine those times when you need a car to get somewhere, spending some of the time weaving around through carts and pedestrians would be much less frustrating if you can kick back and read a book while it's happening. Even more though, there would be less concern of servicing parking for these sorts of regions, so you could still have a few arterial roads to get in and out, far less wasted parking space, and no need to build underground mazes to accomplish it.

MBlume 5 hours ago 1 reply      
The article's unreadable without the photos and we seem to have DOSed whatever's serving the photos. Is there a mirror?
zephjc 4 hours ago 1 reply      
It's interesting that a second article from this site has made it to the HN front page. I've been digging into this concept a lot since the first article was linked from here.

I think traditional, walkable cities are a great idea whose time is more than overdue in North America. Places like Quebec City are a good example, but what really fascinates me is Tokyo, a behemoth of a city with so much that is walkable with one-way streets and wide sidewalk areas, and you can get to anywhere easily via buses and rail links. All these simple one-way streets, connecting to arterial roads with 1 lane in each direction, connecting to highways, create an absolutely massively distributed road system.

If you think i'm exaggerating, pull up Tokyo in Google Maps and pick a spot at random in the surrounding metro area and go to Street View, you will always always land on a one-way road, often with people walking on it.

carsongross 6 hours ago 1 reply      
Amen. But good luck getting it past planning.

We don't build even mediocre cities anymore because, for the most part, we've made them illegal.

alexmayyasi 1 hour ago 0 replies      
This article on an urban planner's objection to suburbs on financial grounds (most succinctly put as suburbs are a ponzi scheme) is relevant for thinking about why this project is -- relative to a more suburban/sprawl alternative -- less costly than it seems:


tbatchelli 5 hours ago 1 reply      
Christopher Alexander wrote extensively about humanistic cities in "A Timeless Way of Building", "A Pattern Language: Towns, Buildings, Construction" and many other books. His focus was in studying how people have built villages and cities over centuries, how patterns have emerged and how these patterns affect the daily life of the inhabitants.
agersant 4 hours ago 0 replies      
If you're interested in this topic, I highly recommend this long series of articles: http://www.newworldeconomics.com/archives/tradcityarchive.ht...
andrewfong 4 hours ago 2 replies      
I've always imagined that a "human-centric" city of the future would simply move most of its automobiles one level up or down. Many dense cities already have subways. It'd be expensive but not inconceivable to move all car-width roads into an underground level or onto dedicated skyways, although the latter seems more likely to create issues with lighting and whatnot.
azernik 4 hours ago 0 replies      
Most of the examples of "good" architecture seem to come from Japan, so let me chime in that from my little experience of walking through these kind of Japanese streets that they are very pleasant and inviting for traveling in by foot, and mix very well with car and public transit thoroughfares used to separate small neighborhoods/precincts.
forrestthewoods 5 hours ago 1 reply      
Fun exploration. I'd love to see something similar but for a city design built around shared self driving cars. I don't put much fundamental value in walkability. I put value in being able to get to a variety of types of things quickly and easily. Keeping those things within walking range of each other is one way. Autonomous vehicles is another.
siliconc0w 5 hours ago 0 replies      
I really like the original idea of epcot - create a city as a rolling 'city of tomorrow' with rapid iteration on design - the way we approach at lot of things we're unlikely to get right the first time.

Say what you want about Walt Disney - epcot as originally envisioned would have been amazing.

jamespitts 5 hours ago 0 replies      
His ideas are great!

There must be a way to finance the planning and construction of a neighborhood along these lines, or finance the political effort it would take to designate a zone "traditional".

In an immediate sense, we can encourage trad neighborhoods by asking city councils to slightly change laws that allow smallness and interestingness to take hold. Let vendors set up stands. Open up alleyways. Close off a few streets to traffic.

Another way is to go big and get mega developers to build post-shopping shopping malls that are actually traditional cities. But the big approach has not worked so well in the past!

cjbarber 4 hours ago 1 reply      
On a serious note, what would the requirements/steps to move towards this be?

My guess is some combination of:

- Money

- Initial pre-committed residents

- Habitable land

- Management

And then the main thing left, is, I believe, approval?

Which leads to my questions:

- What is the legality? Where is it legal? Where is it illegal? Or if legal, what are the chances/what is needed for approval?

aperrien 6 hours ago 1 reply      
Why not make a housing sandwich? (of sorts)

Like this:


It costs a bit of land, but the area would be much nicer.

polarix 4 hours ago 1 reply      
Would this even be legal, given fire codes?
Deaths in the Iliad: A Classics Infographic
16 points by jdnier  2 hours ago   discuss
Announcing a specification for PHP
270 points by keso  12 hours ago   172 comments top 21
maaaats 11 hours ago 7 replies      
After recently having to work with modern PHP, I have to say a lot of the criticism of the language is unfounded. It's changed a lot since I first used it.

But the stdlib is still hard to manage. Different naming conventions, different order on the parameters for functions that do almost the same thing, and every function is global. Couldn't they keep all that for backwards compatibility, but create more sane wrappers and include them as part of the stdlib? For starters, group them by what they work on (arrays, strings, numbers etc.) as static functions on some relevant class ( String::str_replace(...) ), and later have more methods one can call on the objects themselves ( myStr.replace(...) ).

Is this being worked on? Can this spec help with that?

ecaron 11 hours ago 1 reply      
I sure hope Sara Golemon gets the recognition out of this that she deserves (and which the article starts to build.) Having met her at a couple conferences, she continues to demonstrate a brilliant understanding of what it takes to build a programming language WHILE being a tremendous advocate and builder of a community where being a member isn't always... popular.

Rock on, @saramg

kayoone 9 hours ago 0 replies      
Recently i feel there even is a kind of PHP renaissance. I think its a good time to revisit PHP and look at what it has to offer these days.The community is enormous and open source frameworks like symfony2, zend2 or laravel are thriving like never before with solid implementations for nearly everything. With composer there is mature packet management now and in general the code put out for these kind of projects is of very high quality. And then there is facebook pushing PHP forward with things like HHVM, however for most stuff i have worked on, php execution time hasn't really been the bottleneck anyway, but its nice being able to squeeze out even more speed.

These days i also work a lot in node and angular, but PHP (using symfony) is still my goto language for a solid REST backend and/or classic static content based websites.

birkbork 11 hours ago 4 replies      
This is great news for the PHP community, and I for one applaud their effort. Contrary to what many HN hipsters seems to believe, PHP is quite a capable language, and HHVM / Hack is really pushing things forward.

* Hack introduces type hinting, imo the major lacking part in PHP.

* HHVM introduces speed to php. On a personal project calculating perlin noise, I got about 8x speedup on HHVM.

* The specification helps pave the way for more implementations of PHP.

lnanek2 10 hours ago 1 reply      
I'm not really a fan of having a second source of truth compared to in depth material already on php.net. The two will invariably start to disagree and php.net is much, much better than any spec or documentation I have ever read. Using Android is a nightmare compared to php.net because every single thing on php.net has extensive user generated documentation whereas Android is just some broken official docs. I submitted a bug report with a fix for the Android docs telling people to make dialogs in a way that simply crashed and didn't work and it was never merged in for years and years. So official specs tend to suck.
ChikkaChiChi 10 hours ago 1 reply      
PHP is fantastic if you are starting from scratch and you don't necessarily need any third party libraries. PDO is very well done and the native database drivers are some of the fastest available.

With a properly tuned nginx/fpm/apc stack, I've been able to deliver solutions that truly back up the results you see from comparison benchmarks like Techempower.

In many cases in web development, PHP can be the right tool for the job!

Aldo_MX 12 hours ago 2 replies      
As a discussion of any programming language grows longer, the probability of a bashing against such language approaches 1.

Any similarity with Godwin's law is mere coincidence.

juddlyon 11 hours ago 5 replies      
Can someone explain to a layman why this is significant? I'm genuinely curious.
robert_nsu 11 hours ago 0 replies      
This is good and long overdue. I disagree with the claim of it being the lingua franca of the internet though.
frik 11 hours ago 2 replies      
The PHP grammar in BNF starts at line 10354. It not that extensive as some may think and rather similar to what Java BNF looks like. The expression statement is a bit more extensive than in most languages, as PHP also supports the little known template-style (if elseif endif;): http://php.net/manual/en/control-structures.alternative-synt...

Thanks for the PHP spec.

Btw. GitHub says "Sorry, this blob took too long to generate.":https://github.com/php/php-spec/blob/master/spec/php-spec-dr...

mehrdada 10 hours ago 2 replies      
> PHP is definitely the lingua-franca of the internet.

Definitely wrong. If there's a lingua-franca of the internet, it's JavaScript.

joshdance 11 hours ago 2 replies      
Rookie question, but what does a language specification for PHP do or mean? I assume this is good, but don't know why. :)
kangax 8 hours ago 0 replies      
Looks like PHP spec is about twice smaller than ECMAScript 5.1 (http://es5.github.io/)

~42K vs ~82K words.

cottonseed 10 hours ago 0 replies      
At first I thought they were announcing a formal specification for PHP. Who's going to win the race to build the first formally verified blogging platform?
ck2 8 hours ago 4 replies      
Facebook first needs to bring HHVM up to full compatibility before they try altering the spec.

I also discovered Facebook makes all their "contributors" (anyone who does a pull request) sign an agreement with them, which seems weird and not cool. https://code.facebook.com/cla

rafekett 9 hours ago 0 replies      
fantastic work that's long overdue. any commitment from the zend team to implement it? if not it's a specification for HHVM, not PHP.
danso 10 hours ago 1 reply      
Maybe I'm missing something here...but the OP links to what must be a gigantic Markdown file that Github will not serve up...Is the spec meant to be in a giant doc, or will it be split up into smaller sections? This seems like a perfect use for Jekyll if they're going to publish on Github...

In any case, I did a quick-fork and generated a Github page from the Markdown file linked to by OP: http://dannguyen.github.io/php-spec/

xanth 5 hours ago 0 replies      
Javascript is the lingua-franca of the internet not PHP.
spacemanmatt 12 hours ago 1 reply      
What's it been, 20 years?
vithlani 7 hours ago 0 replies      
Hahahah.... what a waste of time and resource. FB would rather direct their resources towards this meaningless crap then run the risk of their top employees getting bored -- and leaving them.
LBarret 12 hours ago 1 reply      
A language without a spec ? Damn, php is even worse than I thought. Still, FB may turn it (with hack and HMMV) into something interesting.
Martha Stewart: Why I Love My Drone
84 points by yurisagalov  6 hours ago   22 comments top 7
PStamatiou 3 hours ago 2 replies      
Related - Just published a huge 10k word article about drones/quads, how to get started, fly and modify them. :) http://paulstamatiou.com/getting-started-with-drones-quadcop...
cianuro 4 hours ago 2 replies      
dharma1 2 hours ago 0 replies      
If you need some 4K/5K drone footage with RED Epics.. http://londonhelicam.co.uk :)

4K showreel here - https://www.youtube.com/watch?v=mrDF4ju6CC0

golemotron 4 hours ago 0 replies      
Is it just me or did she just invite everyone to fly drones over her property and take pictures?
jpatokal 3 hours ago 0 replies      
This, along with "UN discusses plans to ban 'killer robots'", are the two recent headlines that convinced me I'm living in the future.
everbronte 2 hours ago 0 replies      
"I did my best to master the moves and angles that would result in most arresting pictures and video."

Heh. Arresting. Heh.

wyager 5 hours ago 5 replies      
Is it just me, or is the real world closely emulating 80s/90s cyberpunk literature?
Micro heaters cut 87% off my electric heat bill
225 points by dantiberian  10 hours ago   170 comments top 40
dredmorbius 6 hours ago 7 replies      
OK, Paul Wheaton simply doesn't know what he's talking about:

"I think that this does produce some savings, but not as much as you might think. If you set your thermostat to a constant 70, the heater works a little at a time throughout the day. If you drop it to 50 at night or in the middle of the day, the heater stops working, but then when the time comes to warm the house again, the heater has to work at full power for a long time to get the temp back up - thus losing a lot of your savings."


Heat losses are driven by two factors:

1. The temperature differential between the hot and cold sides.

2. The thermal conductivity (or exchange) between the hot and cold sides.

That's straight out of Newton's Law of Cooling / Fourier's Law:


If you're running heat constantly, you're maintaining a constant flow of heat from your interior to the exterior. That is, you're maintaining a high heat exchange rate to the exterior, and you're constantly wasting a large portion of heat.

If you're heating only while you need a warm interior, then as the interior temperature falls, the energy flux to the exterior decreases. You're no longer pumping heat into the external environment.

Yes, you'll run your furnace/heating system continuously for a while in raising the interior temperature, but that is largely adding heat to the interior space, not to the exterior.

The net is expending less energy.

Your most efficient strategy is to turn interior heat down to the minimum essential level (ultimately: enough to keep pipes from freezing), or the minimum level the thermostat allows (often ~50F in the US). My own practice is generally to turn any heating system off entirely at night.

From a moisture management perspective, you also win as cold air has a lower absolute humidity, that is, the quantity of water it can hold is lower. Heating cold humid air reduces the relative humidity, allowing walls and surfaces to dry out.

The overnight heat loss is also a very clear sign that Paul Wheaton is dealing with an exceptionally poorly insulated structure. And a very poor grasp of thermodynamics.

The same principle holds for AC as well, though here you want to increase the temperature setting at which the AC comes on, or disable AC entirely while you're out of the home.

A better way of thinking of this is to minimize the energy input (heating or cooling) when it's not needed.





dredmorbius 7 hours ago 3 replies      
Spot-heating, especially within a leaky building envelope utilizing expensive heat sources (electric resistance) is one option.

But it's hardly the only one, or the best. For northern climates, taking a whole-system approach to home/structure design gets you a tremendously greater payoff in terms of energy savings.

Among the most powerful demonstrations of this I've seen are Thorsten Chlupp / Reina LLC's experiences designing and building zero net energy homes in Fairbanks, Alaska.

His videos are long (~90 minutes) be exceptionally comprehensive. The TL;DR is:

Total envelope. He pays exceptional attention to any thermal envelope penetrations. All emissions (air, water, sewage) pass through thermal exchanges.

Thermal mass. The foundation, flooring, central masonry stove, and a 5,000 gallon stratified thermal storage tank all store and scavange thermal energy both passively and actively.

Moisture control. Heat barriers introduce thermal issues. Chlupp makes use of multiple glazings, window setbacks, and _exterior_ thermal shutters to minimize moisture buildup on windows. Moisture barriers and ventilation of interstitial spaces is designed to clear moisture.

Heat pumps. Rather than create thermal energy directly (other than the masonry stove), Chlupp moves heat using ground-loop heat pumps.

Solar and net metering. Solar panels (yes, in Alaska) and net metering help him arrive at net zero energy. His first-year goal wasn't met due to plug-in hybrid vehicles, an oversight in his energy modeling.

Though conceived as a whole-system ground-up greenfield design, the principles are applicable to a lesser degree as retrofit options.

Oh, and for heating your bed: a 1 liter Nalgene bottle, filled with boiling hot water, and slipped into a wool sock, will heat your bed cozily. Two are almost certainly too hot, but you're welcome to try. And they'll last the night.


Alaska's First Net Zero Energy Homes Performance Updatehttp://fixyt.com/watch?v=Xen_VWyDezY

Path to Net Zero Energy Series -- Alaska's first Net Zero Ho...http://fixyt.com/watch?v=AtHkvpRI6fc


zurn 4 minutes ago 0 replies      
Interesting to think how this might work for cooling instead of heating. It's a harder problem (peltier elements? evaporative cooling with split unit? etc) but with big rewards.
arh68 7 hours ago 2 replies      
Imagine how much more they could save by keeping the heated mattress pad on and never leave the bed! I mostly jest..

The author seems totally unaware of the efficiency gains that a heat pump can provide. A 300W space heater will be easily outmatched by a heat pump that consumes 300W (unless we're dropping way, way below 0C). The efficiency is likely ~3x [1]. I hope the author isn't making this mistake out of disdain for centralized hvac, since window unit heat pumps are readily available for small spaces.

[1] https://en.wikipedia.org/wiki/Heat_pump#Efficiency

XorNot 5 hours ago 1 reply      
Looking at this as conventional power savings is wrong.

It's better to look at this as comfort. I just recently bought one of those 20 watt heat mats, for one specific reason: while using a computer it is impossible to keep my feet warm. Socks, boots, anything? Doesn't work. It was a huge problem while I was studying.

Since I got one, for 20 W, my feet are warm. In fact, my perception of room temperature as a whole has been massively improved. This is a lot less power usage then any type of whole room solution.

g8oz 7 hours ago 0 replies      
In my experience thermal underwear (long johns) should be considered a must during winter. You don't have to live in a place like Canada or Minnesota to make them a standard part of your wardrobe.
nostromo 7 hours ago 3 replies      
People should check out WattVision. It's a little device that attaches to your electrical meter so you can monitor your electrical usage.

What I've found is that almost all of our home's electrical usage comes from heating (heaters, clothes dryers, and hot water).

Everything else is almost a rounding error. For example: I saw almost no change when we switched from incandescents to LED lighting (even in the summer when we're not heating the house) but I saw a large change with efficient shower heads and washing clothes on cold.

harmegido 2 hours ago 0 replies      
I'm sorry, I'm sure this idea/post is valid, but damnit if this isn't exactly what the recent HBO show "Silicon Valley" lampooned in the finale.

I cannot stop laughing.

redcap 7 hours ago 1 reply      
> The bathroom is the one room in the house that is heated normally.

You can get heated toilet seats - they're quite common in Japan.One example: http://www.heatedtoiletseat.com

debrice 7 hours ago 2 replies      
Well, not heating your house enough can also cost you your house as mold and ice can grow in very cold zone of your house. But I do like the ingenuity of the solution.

Shit Norwegians Say: Theres no such thing as bad weather, only bad clothes

jmadsen 1 hour ago 0 replies      
Very much the "philosophy" of heating here in Japan; heaters for single room, heavy futons on the bed with no heater, kotatsu, foot warmers, etc.

Comes from old, leaky wooden houses, but idea is the same. Lot of bad habits here still, but heating the upstairs guest bedroom all winter long isn't one of them

bce 2 hours ago 0 replies      
A similar project is being done by the Senseable Cities Lab at MIT:

Local Warming: http://senseable.mit.edu/local-warming/

Video: http://www.youtube.com/watch?v=5-6i6owLMQk

smallegan 3 hours ago 0 replies      
I have often wondered why we don't all sleep in heated pods (bubbles). All of the wasted heat to keep houses warm at night drives me nuts.
HelloMcFly 8 hours ago 0 replies      
I take a more middle-of-the-road philosophy in my house, with primary reliance on space heaters for room-by-room heating. Why do I care if the kitchen is 72F at 2pm while I'm working at my desk in my office?
willholloway 6 hours ago 1 reply      
Energy is abundant, there is no need to shiver in the cold. Solar forced warm air is inexpensive, simple technology that is very underutilized.

Solar photovoltaics get all the attention, but solar warm air/water is less expensive and simple to manufacture.


raverbashing 7 hours ago 2 replies      

Most people want "summer inside the house" which is absurdly wasteful

Of course, it sucks when changing clothes or taking a shower, but there are ways of heating locally.

mangecoeur 7 hours ago 0 replies      
An interesting approach - though for contrast, a well built passivhaus or low exergy design can achieve similar savings or even net positive. At a cost, true, but at much greater convenience. I feel having to do this is basically admitting that our houses are terribly engineered. And yes, with this kind of system you get problems with damp and mold which can have some pretty serious health impacts.
nkozyra 7 hours ago 6 replies      
I live in Florida.

This entire discussion is bizarro world for me. It costs nearly $400 a month to keep my house at 74deg in the summer.

voidlogic 7 hours ago 2 replies      
>In June of 2010 I moved to a place in Montana with only electric heat.

Living that far north and depending on one heat source is crazy! Think about the power going out when its -30 out... or if you used gas, running out or having your furnace break down.

(Not to mention electric is usually the most expensive way to heat). Most houses where I live have 2 or 3 heat sources. I have wood, LP and electric...

p_eter_p 7 hours ago 3 replies      
A similar approach works in hot climates. A friend of mine saved a substantial amount of money by getting an efficient portable AC unit for his bedroom, and shutting off the main air conditioner for the house at night. In a southern summer, the savings add up quick.
ck2 5 hours ago 1 reply      
My cats are my micro-heaters. Zero extra power use in winter :-)
staunch 5 hours ago 1 reply      
Kotatsu tables really are great. Some pictures here if you haven't seen them: http://en.wikipedia.org/wiki/Kotatsu

Unfortunately even a cheap table in the U.S. is more expensive than it should be. There's an opportunity for someone to create kotatsu tables and things like them for the American market.

dmritard96 6 hours ago 0 replies      
This is a cool approach and actually there is some federal research money available for it. https://arpa-e-foa.energy.gov/ third one down)


We (http://www.flair.zone) were looking into grant funding and saw it. All I could think of was heated/air conditioned underwear lol.

ChikkaChiChi 4 hours ago 0 replies      
Three ladies at my company campaigned heavily for those heated keyboards a few years ago. One shorted out within the first month and the other two stopped functioning within a year.
Swizec 7 hours ago 7 replies      
This is where I really prefer the European model[1] - you heat the whole house with hot water. You make hot water with cheap natural gas. If you're lucky enough, you can even use geothermal.

Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.

As a result, your radiators are turned down to 2 out of 10 all day (heating turns off automatically overnight), and you have to sometimes open a window when it's -13C outside so you don't sweat.

Now I don't know how much people spend on heating when they live in a house house, but my apartment's heating bill this winter was about 30 euro a month[2] and I had to keep all my radiators turned off because the one in the bathroom couldn't be regulated. So that alone was enough to heat everything to extremely comfortable levels.

tl;dr don't heat with air, insulate your fucking house, and install modern windows

[1] Could just be where I'm from, but it seems fairly common in Europe and not at all something I've seen in the US

[2] I think my gramps spends about 2k euro in October to pay for natural gas that heats his house until some time in April. So about 300/month for a ~10 bedroom house because he's got a house that's way too big.

dharma1 2 hours ago 0 replies      
hot water bottles work pretty well. Probably more effective than constantly heating up air. Water is a good storage of heat
cjensen 7 hours ago 1 reply      
Given that he uses electric heating, it's pretty funny the electric company wanted him to switch to florescent. That buys you nothing in those months where the heater is on.

What I'd really like to know is: why not switch to gas?

sdhsdh 7 hours ago 0 replies      
Donch 6 hours ago 0 replies      
Number one link on Hacker News is an article stuffed full of Amazon affiliate links for personal heating products. Something isn't right.
vacri 7 hours ago 2 replies      
Why not use the reptile heater instead of the incandescent globe? Having a light shining right in my face would end the experiment in minutes.
nly 4 hours ago 0 replies      
I just let my computers get dusty and run CPU intensive tasks.
lutorm 7 hours ago 3 replies      
This is why changing out incandescents for CFL's in a heated house does almost nothing for saving energy... and if the heat comes from electricity, nothing for saving money, either.
lukasm 8 hours ago 0 replies      
I wonder what's the home efficiency.
moron4hire 7 hours ago 0 replies      
When I was a kid, we were rather poor. My parents scrounged together to buy a computer for the family, and I started to get interested in programming. But my parents were fearful I'd break their computer (not in a "don't be programmin'" way, but definitely in a "please be careful" way). And then a friend donated a computer to me. And I set it up in my bedroom. And I had my first comfortable winter in that house that year.

Of course, it made summers unbearable. But for the most part, I was used to heat.

neves 5 hours ago 0 replies      
You just can't go the bathroom.
seamusabshere 3 hours ago 0 replies      
best. hn. ever.
jeffjia 7 hours ago 0 replies      
Let's just have Nest...
jondiggsit 7 hours ago 0 replies      
Just install radiant heat everywhere in your house ya cheap bastard
jebblue 4 hours ago 2 replies      
I was really caught up in this story and the effort involved until ... "I wonder if these techniques caught on, could this reduce or eliminate US war for oil?" and then "If I wrote this article 20 years ago might we have never gone to war with Iraq?".

Iraq was _not_, repeat, NOT, N O T, about oil. Iraq was about stability, about a nut case leader who terrorized and killed his own people, who let his sons terrorize people. It was about all the terrorists caught who had evaded worldwide, WORLDWIDE authorities for decades in many cases, found hiding out in ... Iraq.

Hussein disregarded Bush elder, Clinton and Bush junior, covering 3 US Presidencies, both major US political parties. He shot missiles at the very ally planes charged with making him keep his army at bay.

He plotted to kill the very US President (Bush elder) who forced him to back out of Kuwait:


The great forgetting
34 points by prostoalex  4 hours ago   5 comments top
hippich 2 hours ago 3 replies      
so from what i understand, speaking with simple terms (simply because i don't know well topic :)) - any living being, including human, starts with "blank brain" where a lot of interconnections exists and/or created easily. And since memories are really "state" of this very complex system, most of things/events remember-able simply blends and blurres during first few years of life.

For me this means two things - there is no way child will recall events from first couple years of his life. So there is no need to try to show new places, make him excited with particular event/thing. But in the same time, events happening in these early years affects brain (and whole body) development as a whole, so it is very important to make baby feel connected, safe, curious, etc.

Or even simpler - first couple years define "North/South/West/East" directions and then later brain develops within few "degrees" of this initial path.

Algebraic Data Types
79 points by ALee  6 hours ago   6 comments top 5
nice_uname_nerd 14 minutes ago 0 replies      
If you haven't seen any category theory, you might be interested to know that the diagrams the author draws are valuable and important in modern pure math as well. Those last two diagrams totally capture the idea of what a product or variant (coproduct, in math terminology) is.

In general, there are a lot of algebraic structures whose essence is captured by some diagramatic property like these, such as tensor products or fiber products. They're called universal properties. Unfortunately the wikipedia page looks pretty poorly written, but you might find it interesting nonetheless.


jallmann 1 hour ago 0 replies      
Nice article, I never considered the duality of product and sum types before.

The importance of effective ADT usage is generally under-emphasized when discussing the benefits of statically typed FP languages* like OCaml and Haskell even though it is the way to maximize the utility of such languages, IMO.

With the right data representation, composability improves and algorithms fall into place naturally. This is further enhanced by a language like OCaml since the compiler catches type errors and non-exhaustive matches on ADTs, any bugs are likely holes in your application model.

There are many benefits in using ADTs, modules and other type-system features to guide your program design. Others have described those benefits very well already just read anything by Yaron Minsky or Jane Street.

* Data modeling is critical for any problem domain, and statically typed, non-FP languages (Java, C++, etc) certainly have facilities to encourage effective modelling, but languages in the vein of OCaml and Haskell really push to make the type system do as much work as possible.

austinz 5 hours ago 1 reply      
Enjoyed this article. Another good read on ADTs: http://tel.github.io/2014/07/23/types_of_data/, and for a Swift-specific take: http://tel.github.io/2014/07/26/types_of_data_in_swift/
rrradical 2 hours ago 0 replies      
I wrote recently about the option type specifically (called Maybe in Haskell): http://asivitz.com/posts/learn_to_love_maybe_kick_null

Swift has it, but it lets you easily subvert its meaning ('trust me, it's not null'), so I don't think it's as useful as it is in the usual functional languages.

doctorKrieger 4 hours ago 0 replies      
so the monad tutorials stopped being cool?
UK to allow driverless cars on public roads in January
269 points by bane  14 hours ago   70 comments top 10
joncrocks 13 hours ago 2 replies      
UK to allow tests of driverless cars on public roads to start in January.

In the same way that has already begun in the rest of the world. Same legal/insurance issues stand (as elsewhere) and are likely the bigger barrier to adoption.

suprgeek 12 hours ago 7 replies      
When ever I see a new place or country allowing a test of these cars this wired article always comes to mind [1].

I think the two main questions will be liability & drivability -

1) when (not if) these cars get into a serious crash, who is to assume liability? Is it Google who created the algorithm? Is it the Audi integrator who fused Google technology into the Audi? Is it the fault of the mapping software that did not update the fact that the signals had been moved to a different position on that street?

2) More mundane - will a driverless car be able to drive every single place that a drivered car would? When a flash flood closes down the freeway will this autonomous beast be able to drive on the back road that is normally closed to traffic?

Having said that I cannot wait for Cars-As-A-Service where the Cars park themselves & disappear when I don't need them and magically reappear when I do (without humans - Lyft, Uber et al. need not apply).

[1] http://www.wired.com/2014/05/the-robot-car-of-tomorrow-might...

ChuckMcM 10 hours ago 1 reply      
A friend of mine noted that you could put self driving cars on the road in Italy right now and nobody would notice :-) I agree with the consensus that driverless cars are inevitable. And knowing that they are inevitable is kind of like knowing a train is going to derail on a curve before it does. You get some time to think about what is going to happen next.

In the train case you would do things like get movable property out of the way, for the cars you can think about things like a defensible yard barrier. Some people already do this for drunks, but putting a 12 - 14" 'step up' along the edge of the property that borders the street will stop most out of control passenger vehicles. Laws will get tested and litigated, new ways to analyze risk will be developed, planners will want to think about how they design roads/signage/maintenance around them.

I suspect this a 'moonshot' technology, which is one where you can demonstrate it in 1969 but can't actually repeat it commercially until 50 years later in 2019.

notahacker 12 hours ago 2 replies      
For the last decade or so, human learner drivers in the UK have had to pass a video "hazard perception test" based on their ability to recognise potential developing hazards (kids playing near the roads, a cyclist confronted by a line of parked cars, a vehicle approaching a junction onto your lane) at a very early point before their movements make their entry into the roadway inevitable.

This strikes me as something which is particularly difficult for an algorithm to process effectively (without generating lots of false positives, which also fails that segment of the test) especially based on the fairly low resolution video human users are presented with in normal test conditions.

Hope they're not going to waive that for the bots, even if they do have 360 degree vision and superior concentration and reaction times.

smikhanov 12 hours ago 2 replies      
Who will be a vendor of those cars?

It seems to me that it's clear that driverless cars are the future, which is going to become real very soon. Any progressive government would (and should) allow such testing, even given the inflexibility of the state's bureaucratic machine. Allowing is an easy part. The hard part is actually building those cars and to my knowledge no UK firm does this at the moment.

cordite 12 hours ago 3 replies      
How will the taxi unions feel when someone combines uber/lyft with self driving cars?
rmason 9 hours ago 0 replies      
Did anyone else notice in the video that neither one of them were using seat belts? I love this tech. but I am not sure I have this blind a faith in it.
jeffjia 7 hours ago 1 reply      
Self-driving cars need to be trained to run on left side now.
kstop 11 hours ago 0 replies      
But that's the worst month they could have chosen! June would make a lot more sense.
1587 5 hours ago 0 replies      
Eloquent JavaScript, Second Edition
477 points by ingve  19 hours ago   66 comments top 18
UnfalseDesign 18 hours ago 3 replies      
In regards to the book's online version, I like how it has code examples that one can edit and run inline among the book's text. I often find myself, while reading a book on a particular language, opening up a new project in an IDE or a REPL in order to fiddle around with what the book it trying to teach. This makes it much more fluid.

It was a pleasant surprise. It is a nice concept I have not previously seen done. (I'm sure someone can come up with examples of where it has previously been done before but this is the first I personally have seen it.)

poxrud 10 hours ago 0 replies      
Good read. After you finish this book I'd suggest the free Javascript Allonge https://leanpub.com/javascript-allonge/readAn excellent intermediate/advanced javascript book.
aboutaaron 14 hours ago 0 replies      
This was a great reference when I started learning JavaScript. It just didn't go over the language, but also gave a great history of programming in general and why JavaScript is structured how it is. A lot has changed in JS land since the first version came out so I look forward to have the author tackles it/
RevolverOce 18 hours ago 0 replies      
I've been following this book for a while now and I'm pretty thrilled to see its reception here on HN. This book is an excellent introduction to front-end development (and even a little backend since it does include a chapter on Node.js)

It has an excellent balance of design patterns and introductory knowledge to attract the new and also seasoned developers who are beginning to look at javascript more seriously.

(This book is also a great primer for anyone who did not understand Javascript the Good Parts)

thewarrior 18 hours ago 0 replies      
Inspite of all the criticism that Javascript gets it's so easy to just dive in and start messing around. The game projects seem like a lot of fun.
geppetto 18 hours ago 2 replies      
Great book but... is it finished yet? Doesn't seem so [1].

[1] https://github.com/marijnh/Eloquent-JavaScript

TelusX 17 hours ago 3 replies      
This is the best Javascript tutorial out there, and I was eagerly looking forward to this update. From glancing at the text, however, it seems that it doesn't cover the very significant upgrades introduced by ECMAScript 6 "Harmony".

Seeing that the standard is already being finalized towards a release in 4 months[1], this seems like an unfortunate omission in an otherwise top-notch text.

[1] http://en.wikipedia.org/wiki/ECMAScript#ECMAScript_Harmony_....

greg5green 4 hours ago 1 reply      
I am both quite happy and a little sad that the chapter on functional programming was nixed from the first edition.

It was way over the heads of the beginners the book was aimed at, but it sure was fun to try and figure out.

taude 17 hours ago 0 replies      
The original version is one of the readings that I suggest for experienced engineers on our team who are new to working with JavaScript.
mesozoic 14 hours ago 1 reply      
Looking forward to reading it. Is there a place to report bugs I noticed a type in the first chapter

"Casual computing has become become much "

gprasanth 17 hours ago 1 reply      
I've been wanting to read this. Sweet: https://gist.github.com/g-P/cbdfd4a4b982ba8fa04b
derengel 13 hours ago 2 replies      
Why is the paper book delayed until november? also the paper book says it has 400 pages, does the paper book has more content?
niix 14 hours ago 0 replies      
Always wanted to take the time to complete this book. Looking forward to diving into the 2nd edition.
uptownJimmy 18 hours ago 0 replies      
Excellent. I've been awaiting this one. I'm at the perfect sweet spot to make maximum use of it.

And I do love good writing...

andreash 17 hours ago 3 replies      
Mobi or epub version anyone?
silverwind 16 hours ago 0 replies      
I thoroughly enjoyed the first edition, looking forward to this.
cmoon820 9 hours ago 0 replies      
beders 15 hours ago 4 replies      
"These ideas were initially worked out in the 1970s and 80s, and, in the 90s, were carried up by a huge wave of hypethe object-oriented programming revolution. Suddenly, there was a large tribe of people declaring that objects were the right way to program, and that anything that did not involve objects was outdated nonsense.

That kind of zealotry always produces a lot of impractical silliness, and there has been a sort of counter-revolution since then. In some circles, objects have a rather bad reputation nowadays."

Eloquent JS, maybe, eloquent writing. Not in this book.

My First Unikernel
209 points by the_eradicator  13 hours ago   38 comments top 7
enduser 12 hours ago 2 replies      
If it helps to add clarity to what this is about, Xen still requires a host (dom0) operating system, usually Linux but also NetBSD and OpenSolaris. Mirage OS (the basis for building your own unikernel) allows building applications as domU kernels. This is advantageous because it minimizes context-switching and allows all of the code in a Xen VM (domU) to be written in a safer language than C.

So the dom0 OS (Linux) still determines which devices are exposed to the Unikernel. The Unikernel implementation is simple relative to a full "bare metal" OS because it only needs to support the Xen interfaces to block devices, the network, etc., and does not have to deal with disk drives, ethernet controllers, etc.

If you are running your own hardware, you're probably better off using something like FreeBSD + Jails or Linux + LXC (Docker). The Unikernel approach is more appropriate for situations where you want to deploy applications on Xen-based cloud infrastructure (Amazon EC2, Rackspace Cloud Servers) and do not want to waste resources or increase security risk by running a full OS. The physical servers at Amazon and Rackspace are already running a full dom0 OS (probably Linux), so running another full OS on top of that just to run your app is inefficient.

paulasmuth 12 hours ago 2 replies      
This sounds like an awesome and fun project to hack on!

However, optimizing around context switches and task preemptions is something you would usually do if your application is actually bound by IO/context switching, is extremely latency sensitive or when you are trying to squeeze the last bits of performance out of a machine. Why did you choose to build such a microoptimized system in a garbage collected language? Doesn't this defeat the purpose of the whole exercise?

I feel the need for more powerful types and built-in/standardized exception handling too, but since performance seems to be one of your major goals, wouldn't something like C++ be a better fit here? You'd get proper error handling and a good type system (with some tradeoffs) without a significant performance penalty.

On a sidenote, I agree that code written in a functional language with a strong type system tends to be easier to get right than bare C, but this doesn't imply that all low-level code is bug ridden and unsafe. In fact the linux kernel is one of the most stable and reliable pieces of software I've had the pleasure to work with so far. Suggesting there is a problem with the linux kernel because it contains "a large amount of C code in security-critical places" seems a bit dishonest.

616c 12 hours ago 3 replies      
So I have been following this stuff with a lot of interest, but I am not very familiar with Ocaml and have tried looking at Mirage docs with some limited downtime.

If Ocaml can only handle one core and does not do SMP, how does it do in the cloud? Does this mean Mirage unikernels handle only one processor/core in Amazon and elsewhere?

j_s 13 hours ago 0 replies      
See also this discussion of MirageOS from 2.5 months ago:


callumprentice 11 hours ago 0 replies      
As someone who knows nothing about lower level OS type stuff, I found this article very easy to understand, interesting and well written.

Sounds like a lot of fun.

Thank you.

dkarapetyan 13 hours ago 3 replies      
I'm a little confused about the direction things are going in. I like high level languages and I like that the OS manages certain resources so I don't have to. This guy is writing directly to block devices from OCaml. Don't get me wrong it's all pretty cool but there is some kind of dissonance there I can't reconcile. Is Xen the new OS now?
n0body 10 hours ago 1 reply      
interesting, although the old mantra of "hardware is cheap, developers are expensive" is still true. you could hire 10 perl/c/c++/javascript/php/etc dev with ease for your project, but struggle to find one ocaml dev. And even then your ocaml dev will need to know the mirage library, xen and have a good knowledge of way more stuff than your project scope

that said, it's still really cool, but it's not something i'd use, and especially not in production

It takes more than practice to excel
58 points by Multics  7 hours ago   29 comments top 10
zvrba 0 minutes ago 0 replies      
I think the key is "deliberate practice" -- google it; but here's an OK article: http://www.fastcompany.com/3020758/leadership-now/why-delibe...

But before learning about 'deliberate practice', I had first heard a saying that "practice makes permanent". You have to practice with the actual intention of getting better and perfecting your technique, otherwise you're just strengthening the old habits.

Some context for the rest of the text: my hobbies are aikido and an old Japanese sword art, so I practice sword cuts a lot (wooden sword, no target -- yet).

Deliberate practice is hard, it's taxing, both physically but also mentally. It requires not only that you focus on what you're doing but also consciously focusing on how you're doing it. By focusing on what and how simultaneously, you can draw a causal connection between the result (what) and how you achieved it. If you're not satisfied with the result, then you try to modify the "how" in a variety of ways until you feel the result has gotten better.

This is mentally taxing and absolutely not fun. You're watching yourself making mistakes in real time, the mind wants but the body cannot (yet). Sometimes you even need to get a fundamentally new idea about "what" or "how" in order to break the (current) barrier. Suddenly an advice that you got from a teacher a year ago, and which didn't make sense then, makes sense NOW.

And after having practiced for a while (usually up to 50 min; different exercises), I notice that I have reverted to "blind" practice, that I can no longer focus on "how", regardless how much I try. That's when I stop, regardless of how much "real time" has elapsed.


Trying to write ten thousand different sentences will make you a better writer than writing the same sentence ten thousand times.

mcone 6 hours ago 4 replies      
I think this confirms what a lot of us intrinsically felt: Some people are just better at certain things than others. Jeff Bezos came to this realization while he was in college:

"Intent on becoming a theoretical physicist and following the likes of Einstein and Hawking, he discovered that although he was one of the top 25 students in his honors physics program, he wasn't smart enough to compete with the handful of real geniuses around him. 'I looked around the room,' Bezos recalls, 'and it was clear to me that there were three people in the class who were much, much better at it than I was, and it was much, much easier for them. It was really sort of a startling insight, that there were these people whose brains were wired differently.' The pragmatic Bezos switched his major to computer science and committed himself to starting and running his own business." [1]

[1] http://archive.wired.com/wired/archive/7.03/bezos_pr.html

jwatte 4 hours ago 1 reply      
If we believe in evolution as expression of genetic traits,And we believe that intellectual capacity has evolved,Then we believe that intellectual capacity is a generic trait.

(Remains to determine whether intellectual capacity genetic trait varies like "has two arms," or like "height," and of course to try to pin down how to measure it, and count how many "its" there may be.)

ivotron 6 hours ago 2 replies      
From Daniel Kahneman's "Thinking, Fast and Slow": practice AND feedback. Without feedback, you don't know how well/bad you're doing
RachelF 5 hours ago 1 reply      
A lot of it is in the DNA. Here's a study where they compared twins, some who practise music and some who didn't:


kappaloris 5 hours ago 1 reply      
A funny thought: this is a very obvious thing for people who follow the competitive scenes of (valid) multiplayer games. There are lots of cases where progamers get to a high level of skill after an amount of practice that absolutely would not be enough for other people. In the end it's not dark magic, they just tend to already have the right mindset (and experience from other games for example) to make the most of their practice.

An iconic example is the team (Na`Vi) that won the first big DotA2 tournament. The game was in closed beta and professional DotA1 teams got a key at different times. Navi got their key just 1 month before the tournament while other teams got theirs way before. Still, 1 month was enough to beat all other professional teams.

There's a lot of interesting things that one can learn from esports, even just from the sheer amount of data generated (dota2 has almost 10M unique monthly players).

jamesrom 5 hours ago 0 replies      
"Practice does not make perfect. Only perfect practice makes perfect." Vince Lombardi
sidcool 1 hour ago 0 replies      
The discussion here sort of disheartens me. Does it mean that I will be what I was born with? I would like to believe otherwise as it gives hope to achieve greatness, in spite of it not being in my genes.
sp3000 5 hours ago 4 replies      
Why can't we just admit that some people are born with certain genetic traits that allow them to excel in certain fields? Practice would accentuate those gifts and is vitally important, but let's not pretend everyone is capable of everything if they just practiced more.

Hell, even the ability to commit to extended periods of practice requires certain genetic ability. Most people are not born with the ability to hyperfocus like Bill Gates and work for 24 hours straight like he was able to do during the early days of Microsoft.

We accept ADHD has genetic components, and so the ability to focus for extended periods of time (which is what practice entails) is inherently easier for certain people.

caster_cp 5 hours ago 0 replies      
I really, really thought that the article contained practical tips for excel, the MS Office Excel
My Startup School Europe talk: The Technology
163 points by paul  12 hours ago   40 comments top 21
7cupsoftea 11 hours ago 0 replies      
What a great article! Lots to think about here.

I'll highlight one point that I think is really important: Kill all daemon processes. Psychotherapy is a process that is designed to help quiet these menacing internal voices (harmful parent voices, self-doubt etc.). There are different therapy orientations: cognitive-behavioral therapy, interpersonal therapy, psychodynamic therapy, etc. They approach these outdated programs in different ways. CBT tries to kill them by applying logic (e.g., My startup is going to fail! [what rational evidence do you have for that belief?]) Relational approaches try to better understand the threatening feeling or impulse that triggers the harmful programs. It focuses on the defense used to keep the threatening feeling in check and anxiety at bay (e.g., I'm really afraid of failing [emotion = fear of failing], so I become a driven workaholic to try to avoid this outcome and feel less anxiety [defense]). A relatively recent innovation in the therapy space is Acceptance and Commitment Therapy. The key insight is that often the attempt to control, diminish, or avoid pain is what keeps you entangled in the pain. Simply making space for the pain, sinking into it, observing it, and feeling it, is what allows it to become disentangled. This, however, is very hard to do, b/c the natural impulse is to avoid pain and the issues that cause pain.

Here is a helpful short video that metaphorically captures the ACT disentanglement process (Demons on a Boat): https://www.youtube.com/watch?v=z-wyaP6xXwE.

Okay, one last point, I'm game for doing my small part to help reach the impossible goal. This is going to be a collaborative project right? : )

lhh 11 hours ago 1 reply      
I really enjoyed this - really energizing and inspiring. It's always great to get that jolt once in a while.

>> "We now, for the first time ever, have the technology and resources necessary to make the world a great place for everyone. We can provide adequate food, housing, education, and healthcare for everyone, using only a fraction of our labor and resources. This means that we can put an end to wage-slavery. I don't have to work. I choose to work. And I believe that everyone deserves the same freedom I have. If done right, it's also economically superior, meaning that we will all have more wealth."

This is some deep stuff. This would really change everything, and mark a major turning point in human history I think. And the statement that providing these things to everyone would only require a fraction of our resources I think is actually true. The capitalist in me feels that this could never happen, but the pragmatist in me feels there's nothing better we could do to dramatically improve the lives of just about everyone on the planet.

There are so many questions though... forms of collectivism have been tried and have failed many times. Are things different now?

tomp 11 hours ago 0 replies      
> Before I finish, I want to mention my impossible goal.

> We now, for the first time ever, have the technology and resources necessary to make the world a great place for everyone. We can provide adequate food, housing, education, and healthcare for everyone, using only a fraction of our labor and resources. This means that we can put an end to wage-slavery. I don't have to work. I choose to work. And I believe that everyone deserves the same freedom I have. If done right, it's also economically superior, meaning that we will all have more wealth.

Even though I found the whole talk very thoughtful and inspiring, this was the part that resonated with me the most.

> I'm looking for full-stack hackers. People who understand that technology is more than just patterns in silicon. The same patterns and systems of patterns exist everywhere. Capitalism is a technology. Like the internal combustion engine, it's tremendously valuable and transformative, but it's not beyond improvement. The same goes for government, religion, and everything else. We have an incredible future ahead of us, but we won't get there by clinging to obsolete patterns.

I guess I'm a full-stack hacker; I learn incredibly fast and can understand very complex systems. I still have to learn, though, to apply this beyond the world of computers, in ways that leverage technology and have a global impact.

tariqr 25 minutes ago 0 replies      
That was an incredible talk, Paul, many thanks!
graphene 11 hours ago 0 replies      
Paul seems to have failed somewhat in his objective to find deep, if narrow, appeal with this talk. People I talked to were unanimous that it was the highlight of the day, and I agree.

In fact, if YC is taking feedback on these events, I'd suggest having more talks like this, and less of founders chronologically going through their story. That type of talk is also very interesting, but can get a bit repetitive, especially for people who have seen videos of previous startup school talks.

SwellJoe 10 hours ago 1 reply      
Paul's talks have been my favorite, pretty much every time he's spoken at Startup School. I've seen a couple of them in person a few years back, and one (maybe more?) on YouTube. He's among the brightest, humblest, folks I've met who've done really awesome things. The humility can actually be a little deceptive...when I first met him, I thought, "This is the guy that created GMail?" Most of us (myself included), could probably learn something from that.

Interestingly, I think that indicates that paul is more of a Woz than a Jobs. I think it's interesting that he chose to use Jobs as an example of someone we need more of (I'm not really in agreement...had he said the world needs more of Woz or Larry or even Elon Musk, I wouldn't have argued).

gameguy43 4 hours ago 2 replies      
There are echoes of some zen/meditation ideas in here. I'm just starting to get into that kind of stuff. Curious to hear if Paul meditates, and what resources he (and other HNers) recommend for getting into it.
adwf 9 hours ago 0 replies      
This was easily my favourite talk. Really inspired me to double down on my efforts with my own idea.

I'd previously been under-emphasising the AI aspects of what I was attempting, in the worry that people would think an AI-based startup was too difficult or crazy to go for. Now I've just spent the last week rewriting copy and redoing my pitch to deliberately emphasise it. And I feel a whole lot better about it too!

staunch 10 hours ago 2 replies      
We need a mechanism that allows people to go from wage-slavery to creating massive value in the world. YC is one method but it turns down 97% of founders, which by Silicon Valley standards is considered inclusive.

Imagine a YC where the money and decisions came from a crowd of thousands. If "Show HN" had a "Fund" button. The potential for 100x more Googles is there.

rorydh 12 hours ago 1 reply      
Was there to watch, had a chat with you afterwards and can't wait to read it again!
bfwi 12 hours ago 1 reply      
Can't seem to find the videos of the Startup School Europe talks. Will they be put on youtube?
XorNot 5 hours ago 0 replies      
I thought a comment about Gmail didn't really make much sense. I don't know who was opposing Gmail in Google, but it was hardly an orthodoxy. It was essentially obvious from the get-go that Gmail would be huge.
dharma1 2 hours ago 0 replies      
Was there, my favourite talk. Thanks for making the trip down Paul
morganwilde 11 hours ago 0 replies      
Personally, I appreciate the fact that it was read rather than recited. This made it easier to interpret the message as I understood it. Theatrical motivational speeches have the opposite effect on me. So it was perfect.
lesingerouge 11 hours ago 0 replies      
While I was listening to that particular part I had a very distinct feeling that he was reffering to what could be called "nation-hacking". While it's certainly not the only way to change the world, changing laws drastically it's still the most efficient way. And there is really not enough experimenting getting done in this area.

On a related note, I feel that some of the things that might be interesting to study/experiment with might be at the intersection between these three items: anthropology, information technology and law.

discreteevent 9 hours ago 0 replies      
Love what you do - That's refreshing and maybe a bit subversive. (Of course it's been said before in many ways, but rarely now and rarely in this sphere.
josephlord 8 hours ago 0 replies      
It was a really good talk. I thought that I wasn't going to like it to start with but there were some really good concepts and ideas and by the end it was one of my favourites. Possibly the only talk not featuring sharing mattresses in a two room apartment or something similar.

Choose the interesting path resonated as a useful criteria for making some major decisions.

krat0sprakhar 10 hours ago 1 reply      
Awesome talk, Paul! Super inspiring!

> I would sometimes force myself to run a few miles because it's supposed to be healthy, but I never liked it. Then I read a book that said we are born to run, and that it can be fun

Quick question - can you refer the book you are talking about above? I too have a distaste for running but the sheer accessibility for fitness (compared to going to gym) makes me want to develop a liking for it.


swombat 11 hours ago 1 reply      
That was the best talk of the day - but it felt more like an article being read than a talk. Still, I enjoyed it! Glad it's posted.
jongold 9 hours ago 0 replies      
This was so so good; highlight of my day and one of my favourite talks of all time, instantly. Thanks again!
The Crisis in American Walking (2012)
43 points by Mz  8 hours ago   33 comments top 5
teekert 1 hour ago 1 reply      
I was once at a conference in Galveston, Texas. I and some other scientists, mostly from Europe got hungry at 23:00 or so. We walked to the nearby Danny's or Wendy's but it was closed. When we walked away we saw that the drive through was open so we walked in. Strangely, nobody answered at the pole where you talk to the person. Then a car came up, we stepped aside, and someone started talking! So we walked to the car and said, hey that's nice, we thought nobody was there?... And they guy went nuts over that we were trying to steal his order or something... Wow... we stepped back a bit and when he drove on we followed him to the window where we, just as the car left, saw a woman screaming at us that "there is a camera on you!!!" While she smashed the window shut we tried to tell her: "But we have money we just want to eat?"

It was one of the strangest experiences in my life. Later on I realized it was quite a bit threatening as well.

Later we heard from another colleague that he was questioned by police in a not-so-friendly way about what he was doing (he was walking along the road to check out the beach.) During the trip I took after the conference I saw a drive-through ATM and a drive-through pharmacy. And I spoke to a guy who had been to a drive through funeral!

I guess it explains a bit why Google Now doesn't work for me (here in the Netherlands), it keeps pushing me into either public transport or my car while almost all traveling I do is combination of biking, walking and public transport.

I once had a student from Bulgaria, for her it was normal to walk to school for more than an hour. That would be considered strange here as well although biking for an hour to school is certainly not unheard of.

cletus 4 hours ago 3 replies      
I believe that a terrible way to end up is to be essentially infirm in old age or even middle age. The way to avoid this is start healthy habits early.

I can't drive because of an eye condition. Honestly, this has been a bane of my existence for most of my (adult) life. In Australia a non-car lifestyle is possible but very limiting. You have to pick and choose where you live and figure out how to get to and from places.

In Europe the situation is much better overall. In London you don't need a car but it's still awkward if you need to go home after midnight. The Tube stops. Cabs are crazy expensive. The night bus is a freak show. Going out of London is a problem and expensive.

Switzerland on the other hand was (mostly) amazing from a walker's perspective. Living in a rural town sans car might be problematic but you can get pretty much anywhere in the country by clean, reliable trains. I lived in Zurich and got to all sorts of places are Lake Zurich and Lake Luzern for hiking and the like.

I now live in New York City. I have visited a number of parts of the US. In most of the US you are utterly dependent on the automobile in a way that residents of other industrialized nations probably can't quite comprehend.

I've stayed with friends in the Midwest who parked their car 8 feet from the front door of the their condo, drove to work where their car was pretty close to the office and often got food through drive throughs. They'd probably walk less than 500 yards a day.

Most places in the US aren't just pro-automobile, they're anti-pedestrian and anti-cyclist. Things like:

- Limited to no public transport

- Public transport that becomes unusable at certain hours

- Light changes at intersections that may stop a pedestrian for as much as 5 minutes

- Allowing cars to turn right at red lights. This is perhaps the most anti-pedestrian/cyclist law of all. The number of times I've been almost wiped out in this situation is insane.

- Low density housing.

Even some more pedestrian-friendly places like San Francisco still kinda suck (but SF is a lot better than anywhere else in the Bay Area).

NYC is a bit of a pedestrian mecca. As someone who can't drive, I've never quite had the independence and freedom I have right now by living in NYC. Reasons include:

- Pedestrian-friendly light changes (you never have to wait more than about 30-45 seconds for a light change)

- Subway that runs 24x7 and frequently

- Cheap cabs

- No turning right at red lights. Some visitors to NYC don't realize this is illegal in the five boroughs.

So now I live walking distance to work. The downside is that being able to do so is expensive as a single person and the domain of the wealthy for those with more than 1-2 kids.

The thing that really boggles my mind is how blase we as a society are to the 30,000+ people who die every year in the US in motor vehicle accidents [1].

This is the same number of fatalities as 10 9/11 attacks every year. The cult of the automobile simply defies reason.

There are a couple of points worth making about walking as exercise:

1. Some is far, far better than none. You need some exercise simply for proper functioning of your body; and

2. Walking, and exercise in general, is not the primary solution to obesity. According to a calculator, a 200 lb man burns 120 calories by walking 1 mile in 20 minutes. Not a brisk pace at all. A 12oz can of soda has ~140 calories in it.

Now the relationship between calorific intake and weight gain or loss is complex and somewhat controversial in some circles but, generally speaking, if you consume more calories than you burn you will tend to gain weight and if you consume less than you burn you will tend to lose weight. The body makes some effort to maintain homeostasis so minor changes may result in no change at all.

Exercise certainly helps but diet tends to be the far bigger problem.

[1]: http://en.wikipedia.org/wiki/List_of_motor_vehicle_deaths_in...

sien 5 hours ago 2 replies      
Australia is doing well on the walking scales but is a fat country.

Australia is #6 on the obesity rank:


Pehaps it's all the Pie floaters. Or the quality craft beer. Or the fantastic cheese like King Island Brie.


yoodenvranx 5 hours ago 3 replies      
Need a motivation to go out and walk around? Play Ingress!

It's a gps based mix of capture-the-flag and geocaching with a few million players worldwide.

brandonmenc 6 hours ago 6 replies      
Walking burns something like a measly 100 calories per mile. We could double our walking and still not dent obesity.

We have a crisis that involves lack of real exercise (which walking, is not) and excessive caloric intake.

LinkedIn Neutered Rapportive Today
103 points by welder  4 hours ago   18 comments top 8
notlisted 3 hours ago 1 reply      
I have another theory... It's served its purpose and people are onto them...

Let me explain. A while back 'friends' started popping up in my suggestions list. I noticed that many of these were 'private' email addresses, ie email addresses i've used to sign up for a service, and were used only there, and nowhere else. I do not use these addresses to send email, they're only used to receive emails (newsletters etc).

When i approached linkedin about this, they claimed i'd given them permission to access my gmail contacts on the mobile app. When i asked them for an exact date, they could not provide me with one, but responded with inStructions on how to remove these contacts.

I'm 99% sure that i have never done so, i'm very very careful about this (manage a list of 15k+ members of an organization i run). The answer also did not make sense, because many of these suggested contacts should not show up in my gmail address book (receive-only, no interaction).

My theory is that they've used the rapportive lookups to build a database of email addresses checked by my rapportive addon whenever i happen to click on an address in my inbox.

If you search online, you'll find many people complaining about linkedin 'inviting' contacts without the initiative being taken by the user, and others who wonder how linkedin knew that they were acquainted with some of the suggested contacts.

I must admit i have not bothered to gather conclusive proof of this, but like i said, many of the suggested contacts were single-use (generated on the fly on my own domain, anyone not found is forwarded to my admin account).

I have disabled the rapportive addon after their response because i no longer trust it. Did miss it for a while, but with the changes outlined in this article, that's no longer an issue either.

Ps i was one of the first 150k members of linkedin. Used to think they were the only decent social network in town. This trust has been lost forever. Guess that's hat happens when you go public. Growth required at all costs.

kylelibra 4 hours ago 1 reply      
The post offers Full Contact (http://www.fullcontact.com/) and Vibe (http://vibeapp.co/) as alternatives. Does anyone have any other recommendations?
mbesto 4 hours ago 1 reply      
Curious, is there an API that I can send an email string to and get all of their social profiles listed? For example, I put in mike@gmail.com and get facebook.com/mike, twitter.com/mikeguy1, etc

EDIT: Looks like FullContact does this: http://www.fullcontact.com/developer/docs/person/

s4sharpie 4 hours ago 1 reply      
Obviously, there are many reasons behind why LinkedIn took this decision (and indeed made the original purchase decision) and they may be using the technology internally at LinkedIn in other ways. And, I am a fan of LinkedIn and use it everyday.

Having said that, I am baffled by this. While I appreciate that there is a battle own an individual's primary social network and spend more time/content on LinkedIn vs say Facebook. But, IMHO, wouldn't it have been more prudent to build up the functionality of the LinkedIn component while still offering the functionality that 300k plus users obviously wanted anyway? While this will probably be re-offered (it now looks that it is) as a LinkedIn only plugin, LinkedIn are limiting their reach to only LinkedIn users.

Had they continued to build the multi-network capabilities and brought the marketing/reach of LinkedIn to the product, I dare say they could have owned a significant portion of all GMail users and likely been no.1 in the space. Controlling that (and offering preferential treatment to LinkedIn) what definitely add value.

Who knows the end result, but it looks like a missed opportunity that someone else will come in and take.

jwcrux 3 hours ago 0 replies      
It looks like only the front end has changed. I have a Python library (github.com/jordan-wright/rapportive) that directly calls the backend API, and it still works fine.
pcl 2 hours ago 0 replies      
I dunno... I've literally never used any of those buttons, and the new deeper LinkedIn stuff they expose seems useful.
rubyrescue 4 hours ago 3 replies      
326k users? that's... shockingly low
volandovengo 3 hours ago 0 replies      
Still works for me...
A computer algebra system written in Python
112 points by rbanffy  14 hours ago   21 comments top 8
ivan_ah 11 hours ago 2 replies      
Sympy is AWESOME! In particular, http://live.sympy.org is a great way to learn and teach math... I often send links to my students with an entire sequence of steps to find the solution. Can you factor x^2-5x+6 ? (find numbers a,b such that (x-a)(x-b)=x^2-5x+6) http://live.sympy.org/?evaluate=solve(%20x**2-5*x%2B6%2C%20x...(it's like an entire iPython notebook in a URL)

On the topic of sympy, I'm working on this short tutorial---an introduction to sympy based around topics from the standard high school and first-year university curriculum: http://minireference.com/static/sympy_tutorial.pdf

Please don't post the tutorial on HN yet---I'm working out some last typos and I want to time the "official" announcement on HN with the beginning of the school year.

Tyr42 10 hours ago 4 replies      
How is it different from Sage[1]?

(Quickstart here http://www.sagemath.org/tour-quickstart.html, and really awesome cloud version (that requires an account, but is very worth it here: https://cloud.sagemath.com/)

[1]: http://www.sagemath.org/

ubasu 11 hours ago 1 reply      
If you use sympy, I would strongly recommend using ipython qtconsole:


One of the big advantages is that you can print your expressions using LaTeX:


teddyh 10 hours ago 3 replies      
Why would you link to the Github page instead of the projects home page (http://sympy.org/)? Is this a thing now?
juliangamble 4 hours ago 0 replies      
When looking at Computer Algebra, you can't go past the original example of MacSyma (written in LISP).

You can see an explanation of the MacSyma system in Peter Norvig's (head of Google researcyh) Paradigms of Artificial Intelligence (PAIP).





The original development of the MacSyma system influenced Mathematica: http://en.wikipedia.org/wiki/Macsyma

innguest 2 hours ago 0 replies      
I just read some of the tutorial and I must say this is some incredible work. Very powerful tool, and what a great choice of license (BSD). This benefits everyone; I'm very curious to read the source.
S4M 8 hours ago 1 reply      
How does it compare to Maxima? http://maxima.sourceforge.net/
misingnoglic 8 hours ago 0 replies      
How does this compare with SAGE? I want to show this to my old math teacher who taught using that instead.
Poisson Image Editing in Python
40 points by fbessho  7 hours ago   3 comments top 3
dangayle 1 hour ago 0 replies      
I do face swaps at work all the time, for kicks. I'll have to try this out. (I also have to superimpose real images together sometimes, not always just to put someone's face on the Incredible Hulk or whatnot.)
fbessho 56 minutes ago 0 replies      
Hi dangayle, the calculation is a little bit slow for now.It takes about 15 sec against 500x500 images in my environment, and here's an issue ticket for the speed improvement.https://github.com/fbessho/PyPoi/issues/12

I'm not sure how many sec is acceptable for you though.If you've done some analysis on it, it would be great if you can comment on the issue ticket (or even better if you can raise a pull request against it!).

fbessho 7 hours ago 0 replies      
You can download GUI program (from release notes in the repository) and try Poisson Image Editing in your own machine on your own.
Show HN: Markov chains explained visually
971 points by vicapow  1 day ago   88 comments top 41
jgable 1 day ago 2 replies      
Beautiful. I had seen Markov chains mentioned before, but had not looked them up. Skimming the wikipedia page made sense (it's a state machine with transitions determined by probabilities instead of defined events), but I would not have had an intuitive understanding of why they are useful. The explanation mid-way down about modeling the distribution of sunny and rainy days really made it click for me.
richcuteguy34 1 day ago 1 reply      

Here's a model of chutes and ladder using Markov http://www.datagenetics.com/blog/november12011/index.html

And another for Candylandhttp://www.datagenetics.com/blog/december12011/index.html

cscheid 1 day ago 1 reply      
This is really nice.

Minor nit #1: https://www.dropbox.com/s/2meqa8hhen9ztba/Screenshot%202014-... Seems like the graph visualization is sticking to the wrong coordinates (dragging it to the left doesn't help; it moves back to the center)

Minor nit #2. I'd love to see a visualization of the "probability mixing" interpretation of markov chains and stationary distributions, which is what PageRank is really about. That is, it'd be really nice to have a visualization of the fact that Markov chains are ultimately memoryless (it eventually doesn't matter in which state you start for the distribution of events). I think it could be done by exchanging "probabilities conditioned on the past", which is most easily done by multiplying the entire probability vector by the stochastic matrix and visualizing that.

murbard2 1 day ago 0 replies      
Now look up Hidden Markov models, http://en.wikipedia.org/wiki/Hidden_Markov_model

How they can be calibrated in the finite casehttp://en.wikipedia.org/wiki/Baum%E2%80%93Welch_algorithm

And how they can be evaluated for arbitrary modelshttp://en.wikipedia.org/wiki/Particle_filter

itodd 1 day ago 0 replies      
This is fantastic. I have encountered markov chains in my career and always thought of them as a black box. This simple visualization makes it so easy to understand what has previously been so hard for me. Thank you.
tel 1 day ago 0 replies      
The one thing to add to this is that usually each state doesn't emit a single token ("I am in state 1" then "I am in state 2") but instead you assume that each state has a range of possible actions and the likelihood of a choice of action varies with state.

So if might not be that your model is sunny versus rainy but instead cold front v warm front. Since rain is more likely during a cold front your observation of rain increases your belief that the system is in the "cold front" state.

sitk 15 hours ago 0 replies      
This is an absolutely magical and intuitive (not to mention beautiful) way to imagine the complex mathematical concept of a Markov Chain. This is the exact sort of pedagogical tools that MOOCs and other educational software platforms need to build and adopt to bring education into the 21st Century and finally replace traditional teaching methods. How does this compare to what even the best teacher could draw on a whiteboard? Teachers will still play an essential role in the emotional and social development of students, and they can then focus their energy on these things which software probably will struggle to ever replace.
sinwave 1 day ago 0 replies      
Thought I'd point out a little typo. In your table with sliders for adjusting probabilities of state transitions, the P(B|B) probability reads "P(B|A)".

Edit 1: Also, P(A|B) reads "P(A|A)".

Edit 2: Not trying to be too nitpicky, though. It's a really nice visualization. Really excited about the growing use of d3 to visualize algorithms. Is this inspired by Mike Bostock's post by that title?

elwell 2 hours ago 0 replies      
And where is Temple OS creator's comments? I believe they are markov chains of a sort.
ajanuary 1 day ago 0 replies      
Presumably in the B row it should read "P(A|B)" and "P(B|B)"
beenpoor 1 day ago 4 replies      
Thank you! I understood what Markov Chains are now. Nicely done and in a simple understandable fashion.

I am also trying to understand what they call Hidden Markov Model (specifically, I just cannot wrap my head around how it gets used in speech. They just look like entirely different things). Would be awesome to see an update with the Hidden MM.

devindotcom 1 day ago 5 replies      
I've seen Markov chains applied to language generation - producing sentences that make sense grammatically but not literally. Anyone know what the connection is here? I think I have an idea but would like to see if it gets independently verified by someone else.
romaniv 1 day ago 0 replies      
dekhn 1 day ago 0 replies      
Back when I was in college (~20 years ago) I was struggling to understand generative models, and I asked my CS professor.

he said, "imagine god is sitting around emitting DNA sequences. She has sevearl 4-sided biased dice, rolls one of the 4-sided die, BAM, emit an A! Again, roll the die, BAM, emit a A! Roll again, BAM, emit a T! Now, imagine god is a fickle person, and between rolls, decides to roll a die to decide which of the biased die to roll.

For some reason, that helped.

chenshu_ivory 1 hour ago 0 replies      
Look so cool! Still hard to understand
saganus 1 day ago 0 replies      
Very nice! I've never had to work with Markov chains but I've read about them and they seem to pop up in lots of places.

Nice and simple and interactive explanation.

jesuslop 1 day ago 0 replies      
Gian Carlo Rota is always a pleasure to quote, despite he knowing it. One from his reminiscence about Jack Schwartz, in his "Indiscrete Thoughts" Book (TL;DR: Markov Chains seen as random maps):

The first lecture by Jack I listened to was given in the spring of 1954 in a seminar in functional analysis. A brilliant array of lecturers had been expounding throughout the spring term on their pet topics. Jack's lecture dealt with stochastic processes. Probability was still a mysterious subject cultivated by a few scattered mathematicians, and the expression "Markov chain" conveyed more than a hint of mystery. Jack started his lecture with the words, "A Markov chain is a generalization of a function." His perfect motivation of the Markov property put the audience at ease. Graduate students and instructors relaxed and followed his every word to the end.

Beuatiful visualizations.

vitd 12 hours ago 0 replies      
Great explanation, but wow, those animations were awful! The movement was great, but the seizure-like jump every time it hit a state was unwatchable. I had to cover them up to get through the text.
granttimmerman 1 day ago 2 replies      
I created a Markov chain generator: https://gist.github.com/grant/561834963dc526495c45

var numNodes=10;var roundNum=100;var a=[];for(var i=0;i<numNodes;++i){var connections=[];var sum=0;for(var j=0;j<numNodes;++j){var randNum=Math.random()/numNodes;randNum=Math.round(randNumroundNum)/roundNum;connections[j]=randNum;sum+=randNum}connections=connections.map(function(e){var t=e(1/sum);t=Math.round(troundNum)/roundNum;return t});sum=connections.reduce(function(e,t){return e+t});connections[numNodes-1]+=1-sum;connections[numNodes-1]=Math.round(connections[numNodes-1]roundNum)/roundNum;a[i]=connections}console.log(JSON.stringify(a))

Copy and paste the output into the side bar.

vicapow 1 day ago 1 reply      
There was a bug in the playground earlier that I just fixed that allows you to share your Markov chains via the url hash. For example: http://setosa.io/markov/#%7B%22tm%22%3A%5B%5B0.9%2C0.1%2C0%2...
dnautics 1 day ago 1 reply      
This is really great, but could you put in a bit how some transition matrices aren't markov (e.g. [0 1; 1 0]) and the convergence criterion where you can take M^n n->infinity and get the occupancy of the states?
nabeelahmed13 1 day ago 3 replies      
This is at a tangent, but I'm a fresh CS undergrad and this simple explanation really hooked me.

So my question is, where can I find more of this stuff? MOOCs are tough to manage with university, but if I wanted to learn more about these mathematical concepts presented in an interesting way, where should I start looking?

I'm a tad bit indecisive about how good I am with CS theory but I know if I took the leap and mastered some basics I would enjoy it. Any recommendations will help.

bdavisx 1 day ago 0 replies      
Great! It would be nice to be able to stop the animations though, they are distracting while you are trying to read the text.

The sunny/rainy probability example is perfect as a scenario.

CharlesMerriam1 1 day ago 0 replies      
Very nice concept; a mvp

Just on first glance:1. first diagram and others, ball jumps from beginning of BtoA arc to B without sliding along the arc.

2. second diagram box was no P(B|B). That is boxes are mislabeled.

3. strange, but arcs are sometimes at an angle. It appears to happen if they are scrolled to, but no if drawn on the initial screen.

4. while the R S on the next diagram does settle to a steady state, it starts with random Rs and Ss marching across at random rates.

Good Start!

lewis500 1 day ago 1 reply      
Man the text is really well written! Am I right, everyone?
matthewcanty 18 hours ago 0 replies      
I'm outta control on this page!

[ [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1], [0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1]]

kevinwang 1 day ago 1 reply      
That's pretty cool. The markov chain diagrams seem very similar (identical?) to deterministic finite automota. Would it be correct or incorrect to say that a Markov Chain can be thought of as a DFA where the changes in state are determined by probability?
tigroferoce 21 hours ago 0 replies      
Great explanation! Very easy. It could be perfect if you added some easy to understand real life examples to play with.
lobotryas 1 day ago 2 replies      
Has anyone thought about or attempted to model game AI with Markov Chains instead of decision trees? Ex: NPCs, wildlife or enemies that use Markov Chains to react to their surroundings.
granttimmerman 1 day ago 0 replies      
_nullandnull_ 1 day ago 1 reply      
Beautiful. What did you use to create the graphics?
Max_Horstmann 1 day ago 0 replies      
Very cool. Would love to see this generalized to an interactive visualization of Markov Decision Processes (MDPs).
_raoulcousins 1 day ago 1 reply      
Can I use this for my class? Creative commons with attribution?
skriticos2 1 day ago 0 replies      
This totally reminds me of SpaceChem on higher levels (puzzle game for programmers).
lnkmails 1 day ago 0 replies      
I would not "require" people to know Markov chains but I am usually surprised how many programmers have no idea what it is and how it works and how it can be used. It is a very powerful tool to model queues which is something most distributed systems deal with :).
hyperliner 1 day ago 1 reply      
"For example, the algorithm Google uses to determine the order of search results, called PageRank, is a type of Markov chain."

I had to research that to understand it: http://en.wikipedia.org/wiki/PageRank

Here is some key text from Wikipedia:

Google recalculates PageRank scores each time it crawls the Web and rebuilds its index. As Google increases the number of documents in its collection, the initial approximation of PageRank decreases for all documents.

The formula uses a model of a random surfer who gets bored after several clicks and switches to a random page. The PageRank value of a page reflects the chance that the random surfer will land on that page by clicking on a link. It can be understood as a Markov chain in which the states are pages, and the transitions, which are all equally probable, are the links between pages.

If a page has no links to other pages, it becomes a sink and therefore terminates the random surfing process. If the random surfer arrives at a sink page, it picks another URL at random and continues surfing again.

lynchdt 22 hours ago 0 replies      
This is really cool, nice work.
suchetchachra 1 day ago 0 replies      
Excellent visualization!
dolom 1 day ago 0 replies      
Really cool: well done!
mrcactu5 1 day ago 0 replies      
can I fork these?
Pinn2 1 day ago 0 replies      
The problem with Markov chains is that they are named after a person, which makes math seem more like a "private club". For instance, why use "abelian group", when "commutative group" will do? The reasons for wanting to be a member of an exclusive group are psychological.
Lytros Illum Is a Camera for Serious Photographers
34 points by aaronbrethorst  7 hours ago   18 comments top 6
georgemcbay 6 hours ago 1 reply      
"Lytros Illum Is a Camera for Serious Photographers"

Meh, not really. I mean, it is interesting, but the title isn't really correct and also not justified by anything written in the full article.

I'm a fairly serious hobbyist photo-taker and while the Lytro appeals to my geeky experimental side it has some major issues for use in "serious photography":

While being able to refocus the image is nice, no matter where you set focus the sharpness is pretty shitty relative to nice, sharp modern conventional sensor/lens combos. The images I've seen from the Illum are better in this regard than the previous oddly shaped box camera Lytro released, but still quite a bit off of conventional digital cameras.

4 megapixels, while perfectly fine for web-based images (though with the acceleration in adoption of HighDPI displays, even this is changing), is seriously limiting if you intend to make prints much larger than a 4x6", especially if you also have to crop at all.

Also, while the Canon 70-200mm is ~$2500 as noted in the article, Tamron makes an f/2.8 70-200mm that is for all practical purposes just as good for $1,400 which is less than the price of the Lytro even if you add in the cost of a used older low-end APS-C DSLR body (and even an older low-end DSLRs will have many more megapixels and overall image quality at HighDPI or print sizes) to go with it.

I still find the Illum (and light-field photography in general) interesting from a tech perspective and and would probably buy one to fuck around with if they cost like $400, but in the price range the Lytro retails for I would recommend anyone "serious" about photography pick up the Sony A7 with the 28-70mm kit lens. You won't be able to refocus or perspective shift the images, but the images will be sooo much nicer and more flexible if you intend to print or display them at very high resolutions.

I really wish I could be more positive about the camera because I want to see where light-field photography ends up down the road if it is pursued, but the $1,600 price really puts it in an odd place where it is too much (for most of us) to buy as a toy but too limited to buy as a serious piece of photography gear.

devindotcom 6 hours ago 3 replies      
I love this technology and it is fascinating as hell, but as a photographer it leaves me absolutely cold. I just cannot seem to find a good reason to use it other than the simple novelty one feels when first navigating one of the photos. That doesn't remain novel for long, and the contrived compositions that make the best use of the technology tend to reflect a lack of what, in my own opinion, goes into a good photograph. The results of the camera are simply not compelling to me.
DenisM 6 hours ago 0 replies      
In related news, people are working on light-field display: https://news.ycombinator.com/item?id=8109515
sjs1234 6 hours ago 1 reply      
What are the issues with applying this to a video camera instead? That seems like a more interesting use case.
stevewilhelm 5 hours ago 0 replies      
On a similar topic, does anyone watch 3D television?
LeicaLatte 2 hours ago 0 replies      
What? No. Cameras are complicated enough.
Android IMSI-Catcher Detector
51 points by slashdotaccount  9 hours ago   12 comments top 5
slashdotaccount 9 hours ago 3 replies      
Hello, everyone! Since Google does not seem to be interested in fixing the huge security hole of not showing a ciphering indicator on Android, it appears as if they get paid (or are forced to) not fix it. For all of you that are sick of getting spied on through IMSI-Catchers, Silent SMS and alike and want to do something about it, here's a great project you should check out: "The Android-IMSI-Catcher-Detector" (AIMSICD). It is an Android open-source based project to detect and (hopefully one day) avoid fake base stations (IMSI-Catchers) or other base-stations (mobile antennas) with poor/no encryption.

This project aims to warn users if the ciphering is turned off and also enables several other protection-mechanisms. Since it is under constant development, they are constantly searching for testers and security-enthusiastic developers with balls. Don't be shy, feel free to contribute, in any way you can on GitHub: https://github.com/SecUpwN/Android-IMSI-Catcher-Detector

noyesno 7 hours ago 0 replies      
This reminds me of the early days of GSM where Nokia phones showed a broken lock icon if the air interface between the mobile phone and the base station did not use encryption. At the time at least France had disabled the encryption and the indicator caused some interesting discussions.
nerderloo 3 hours ago 0 replies      
It seems only 2G connection is crackable. Are we safe as long as the device is on 3G/4G network? We should just disable cellular radio when you see the device is on 2G suspiciously in the middle of city(around demonstrations, I suppose)
cowbell 3 hours ago 1 reply      
This sounds like such a good idea, I think the US government will outlaw it.
couchand 8 hours ago 1 reply      
Any chance you could quiet the headline a bit? I recognize you have a good project but that title's awfully loud.
Pwntools CTF Framework
27 points by lelf  8 hours ago   6 comments top 2
keerthiko 6 hours ago 1 reply      
Was I the only one who found it hard to figure out what CTF referred to here without having to actually look at the code? I haven't actually looked at a collaborative translation framework before, besides wondering what ctfmon.exe was in my task manager.

My everyday experience with the acronym has been in the context of Capture The Flag, and given that it originated with FPS games (Quake, Unreal, etc), the name pwntools makes it only further misleading (or was it supposed to be clever?). I would have appreciated the github readme filling that acronym in at least one place.

jmgrosen 1 hour ago 0 replies      
Did you guys change your name from Pwnies? Too bad, I liked that name :(

Glad to see you're still actively developing this, though -- I've used it more than once :)

FCC chair accuses Verizon of throttling unlimited data to boost profits
137 points by ossama  7 hours ago   6 comments top 3
cma 7 hours ago 0 replies      
Isn't he aware that the device neutrality terms (which BTW i don't see as relevant, but he brought them up) dont apply to 4G unlimited plans grandfathered in after a settlement with the.. FCC? New plans have to allow tethering, grandfathered unlimited plans, under the terms of the settlement, don't. However, maybe unlimited plans that aren't on contract aren't covered by the settlement?
FlailFast 4 hours ago 0 replies      
Next up, FCC chair accuses scapegoat of not providing good enough distraction while he dismantles net neutrality.
jmac-sjc 7 hours ago 2 replies      
My guess is that the FCC will win this one, but as trade, Verizon will win a future (important) one they want. That way Mr. FCC will be seen as fair and balanced...
BitPay's New Plan
127 points by josu  16 hours ago   45 comments top 11
bitcoinnerd 10 hours ago 3 replies      
2 things I am thinking:

1. If Bitpay was making a lot of money on payment processing, would they have gone to free forever? No!

- The reason is payment processing does not generate much cash! Certainly nothing that can support a 60 person team that bitpay has.

- There is very little bitcoin payment volume and not expected to be much in the near future. Honestly, despite how much press coverage it gets whenever a merchant accepts bitcoin. No one is doing big volume through bitcoin. Certainly not at a volume that is meaningful to a processor.

- Bitpay says they processed 100m in transaction last year. That is false. Bitcoin price was around $100 most of the year. And in December it went to $1000/btc. And so they took $1000 and applied that to all the sales throughout the entire year

- They recently have a massive change in strategy when Tony Gallipi stepped down as the CEO and Stephen Pair became the CEO (original CTO). This is important, because since then the strategy became open source focused (very much like Redhat for bitcoin)

2. Bitcoin payment processing has incredibly low barrier to entry.

- Unlike visa and mastercard which has massive barrier to entry. Vanilla Bitcoin payment processing really just involves less than 100 lines of code. Like

Step 1: Use BIP32 to safely and securely accept payments (Keep the private key offline and derive addresses using the master public key on the server).

Step 2: Write a little script to run locally to hook up to a API to sell the bitcoin. Voila, you have basically got bitpay.

Like many other internet based service, the fees eventually trends towards 0. Unfortunately, monetization of bitcoin payments is going to look very different than the traditional visa/mastercard/paypal model and it cannot come from vanilla fees alone.

Because what used to be proprietary network/technologies has been mostly replaced by the bitcoin protocol itself. And so value has to come from somewhere else.

donretag 13 hours ago 3 replies      
Remember usa.net/netaddress.com?

"With USA.NET Net@ddress, ... have one email address for the rest of your life for free!"


I'm not buying into free + forever.

josu 16 hours ago 1 reply      
From reddit[0]:

>Hey, everyone! This is BitPay. We know you have a lot of questions so we'll be doing an AMA at 12:00PM EST (today) on r/Bitcoin

[0] http://www.reddit.com/r/Bitcoin/comments/2c510m/bitpays_new_...

rhino369 14 hours ago 5 replies      
I'm sure they are just hiding the fees in the exchange rate. Which could be much more than 1% or whatever they were charging.
pbreit 12 hours ago 0 replies      
Rant: blogs lacking links to the company's web site (towards the top) are annoying.
crxgames 12 hours ago 0 replies      
This is fantastic news. I just setup my online store to support Bitpay last night! Can't wait to see how this turns out. Even if they end up charging a percentage, paypal/stripe are almost 3% so anything less than that is great.
twodayslate 7 hours ago 1 reply      
They are planning on making their money thru their Business and Enterprise plans


wesley 13 hours ago 2 replies      
Very nice, does anyone know if they'll ever accept anything other than bitcoin? Altcoins like NXT etc?
ericcholis 13 hours ago 1 reply      
Anybody have reading for a merchant evaluating Bitcoin as another payment option?
StavrosK 12 hours ago 1 reply      
Can someone explain what this is, exactly? Is it a fee-free way for people to accept Bitcoin on their site/shop?
kakashi19 12 hours ago 1 reply      
the part scares me the most - "Free Forever"
The making of the Raspberry Pi Model B+
25 points by nkurz  7 hours ago   1 comment top
edent 31 minutes ago 0 replies      
I've really been enjoying the new podcast they're putting out. Some great interviews with big (and not so big) names.


Immutable Data Collections for Javascript
175 points by gagan2020  19 hours ago   77 comments top 13
leebyron 15 hours ago 5 replies      
Hey, I'm the author of this library. It's definitely inspired by mori (and clojure and Haskell) and the reason I ended up building something different was to present a more JavaScript friendly API (and academically, to learn about HAMT). I've built this over the last couple weeks, and we are not using it internally yet - but I wanted to ensure development of it happened in public.
falava 18 hours ago 4 replies      
There is also Mori[1], a JavaScript API for using ClojureScript's persistent data structures:

  [1] http://swannodette.github.io/mori/

ScottBurson 12 hours ago 0 replies      
If anyone is interested in functional collections for Common Lisp or Java, have a look at FSet: http://www.ergy.com/FSet.html
vineet 17 hours ago 2 replies      
Sounds like more of the pieces of React/Flux are being opensourced. :-)

Interesting to see references to TypeScript. Is it prevalent at FB?

Strilanc 8 hours ago 3 replies      
I have to admit, I find it odd that we name immutable data structures based on what they don't do instead of what they do.

Of course, what they do is efficient persistence. You want a snapshot of the data? You want a non-volatile reference? You've already got one! That's the feature. They should be called persistent data structures.

abaco 17 hours ago 2 replies      
Bit confused (ignorant actually) here.Can someone give a 'real world' example of the benefits of immutabile objects in js?
derengel 14 hours ago 0 replies      
So you can use the Clojurescript/Om/Reagent/React model without Clojurescript, nice for people who don't want or can't jump into Clojurescript right now.
jannes 17 hours ago 1 reply      
I wish the README would tell us a little bit more about how to use it in conjunction with React. Especially the logic for shouldComponentUpdate() would be interesting.
colinramsay 16 hours ago 1 reply      
React's documentation also discuss their immutability helpers [1]. This new library looks like a better way of implementing this though. Will the documentation be amended to discuss use of immutable-js?

[1] http://facebook.github.io/react/docs/update.html

33a 15 hours ago 0 replies      
Also relevant (and not included in this collection) is the following functional red-black tree implementation:


nawitus 16 hours ago 1 reply      
Hmm, it seems to be written in TypeScript, but the source is only provided in JavaScript.
dreamdu5t 15 hours ago 1 reply      
The original npm package "immutable" was https://github.com/hughfdjackson/immutable npm install immutable@1.4)

Did Facebook buy the npm name from hughfdjackson, did he give it to them, or did NPM switch ownership?

Kiro 14 hours ago 2 replies      
I don't understand this whole immutable thing... Why not just avoid changing the data once created? Why do you need a library?
Show HN: NomadList The best cities to live and work remotely in
579 points by pieterhg  20 hours ago   272 comments top 86
pieterhg 19 hours ago 16 replies      
Hi HN! I made this. Here's some info on the data before everyone goes berzerk :)

Firstly, it's crowdsourced from this spreadsheet http://nomadlist.io/edit/ so it might not be 100% accurate.

Secondly, NomadCost != cost of living. NomadCost is based on short-term staying in a hostel, hotel or apartment in the center, working in a coworking space and having a basic meal three times a day. That's the average digital nomad's lifestyle. They move around every few months, so they can't rent long-term. So NomadCost will be way more expensive than cost of living for a resident.

I'd like to monetize this by selling city specific nomad guides on how to set up in each place and letting people find jobs remotely. Hope this helps! I think this is the future of work, so I'm very happy to help push this.

P.S. this is part of my goal to launch 12 startups in 12 months (see http://levels.io/12-startups-12-months)

compare 19 hours ago 2 replies      
Great concept. One feature request: Better calculations for cities with Bi-modal price distributions.

Certain cities have a extremely bi-modal distributions of pricing. I.e. they can support both the "broke artist" lifestyle, and the "upper middle class" lifestyle. Two separate cost distributions. If you try to take the mean or median of these cities, you'll end up either arbitrarily landing on one of the distributions, or a nonsense number in the middle.

A good example is Manhattan. For example, pizza can actually be cheaper in Manhattan than Sofia. In Manhattan, the broke artist lifestyle of living with multiple roommates who barely know each other, all sharing a rent controlled apartment for a few hundred dollars a month is more socially acceptable and much more common. Just taking prices from the realtor-controlled apartment websites is a poor reflection of reality. Almost no one except the richer consultants bothers with a full-time coworking desk in either city. In this case, Manhattan can actually cost less than Sofia.

So, I think the "broke artist" price distributions would better reflect what a remote working nomad would be looking for, instead of the "upper middle class" prices.

peteretep 19 hours ago 2 replies      
You need to include visa situation, because Bangkok is 3rd, but unless you're planning to start a Thailand-based business via the BOI, you're working there illegally if you don't have a work permit, and they're cracking down on all sorts of visa irregularities at the moment.
TheMagicHorsey 14 hours ago 0 replies      
I don't know if I'm the first one to say this, but I have discovered that Sebastapol, CA, which is an 1.5 hours north of San Francisco, has fiber internet, and a significantly lower cost of living. Its also in a fairly beautiful and wooded part of Northern CA. O' Reilly Associates is based there.

I'm surprised it isn't more jam packed with start ups.

Oh yeah ... there is nothing to do there. So you will have to just admire nature and work. And then commute to SF for your meetings.

If this explodes in popularity, I hope someone will credit me for leaking the secret.

optymizer 15 hours ago 3 replies      
You need way more data points. I would add crime statistics to this for example or probability of getting arrested and beaten by the local police, and the average cost of bribing officials/administrative workers.

For example, Sofia is #5, but, having lived there for a few years, it is absolutely not the #5 best choice, by far. That said, it's not a bad choice, it works for Telerik after all.

imjustsaying 20 hours ago 3 replies      
Ho Chi Minh is almost twice as expensive as Hanoi? I didn't make it to Hanoi, but everyone told me it was the more expensive of the two. HCM is really cheap everywhere you go if you just stay out of the financial sector.

Keep in mind AirBNB doesn't seem to get sites below the $15 range, and a lot of hotels that are in this range don't list on internet exchanges either. For example in Ho Chi Minh there's a few decent airconditioned hotels next to Bui Vien for $10 a night but you wont find them online. Also in Southeast Asia I've found you can rent most everywhere for 30 days at a time, which in my mind is short term when I consider all the minimum 12 month leases I had to get in the US.

Good job though, I like that you're scraping other sites. This should be good to use in conjunction with Numbeo, which has its own biases.

greggman 20 hours ago 3 replies      
I'm curious where the data comes from? I see that it's a spreadsheet but how is it verified?

For example, I don't know what the average price of a co-working space is in Tokyo but I do know that "The Terminal" in Harajuku is only $150 a month. It's open from 11am to 11pm and includes free drinks (soda, coffee, tea).

Co-ba, has more than one location, the one in Shibuya is $160 a month and is open 24 hours.

The Open Source Cafe in Shimokitazawa is tiny but also similarly priced as is one I visited in Koenji (sorry, I forgot the name).

So, I'm curious where that $444 a month estimate comes from.

Rent is also iffy. It currently says $70 a day but rent varies widely depending on your standards and how far out of the center you're willing to live. I know people that have had a large 3bd apt for $1200 a month only 2 stops out various main lines on the express. (which might be like 12 local stops). Whereas downtown it might be $1200 for a studio but then again it depends on the quality. I know guys living in Nishi-Azabu for $600 a month.

brc 2 hours ago 0 replies      
As someone a bit further up the snakes and ladders board than a lot of younger nomadic types, I woudo like to see a specialised house swapping community around remote workers. This woudo be houses with necessary workspaces, connections and the like. I would happily swap for periods of time during the year, but with dependents in tow. This type of thing woudo be excellent for relocating into time zones suitable for specific projects.
nikster 2 hours ago 0 replies      
I live in Chiang Mai, which is listed #1 on the list - and yeah I'm here because I love it.

But the picture you included is the White Temple in Chiang Rai. It's not in Chiang Mai. Might as well put a picture of Chiang Mai there, particularly if it's on the #1 spot. Not like Chiang Mai doesn't have any temples, there's hundreds and hundreds of them ;)

gear54rus 41 minutes ago 0 replies      
Fahrenheit, seriously?:(

Good concept though.

salih 13 hours ago 2 replies      
As a Tunisian I feel obliged to put my 2 cents.

The cost of life is pretty cheap around here ($500/month is the average salary for a teacher, the minimum income is around $200/m), and its getting cheaper with the decline of the tunisian dinar Vs $ &

I live near the cities of Sousse & Monastir, and i can share few thoughts:

- rent for a decent apartement is about $300/m in the city and less than $200 outside

- food is relatively cheap around here, with a wide variety of fresh fish

- Monastir is a beatiful city, good climate, excellent beaches, the travel to the aeroport cost less than15 min and 50 cent , with weekly/biweekly flights to major european cities.

- Tunisia is actually very safe and stable, major touristic destinations(hammamat, sousse, monastir, djerba (which btw is a very decent destination) are given more attention by the Interior minister.

- internet quality is not on par with the 1st world, 8Mb cost around $40/ m

- french is widely spoken, english is understood especially by youth

- wikitravel have some good ( and accurate) articles about tunisia & tunisian cities

maga 19 hours ago 3 replies      
As a nomad who wouldn't mind settling down, I'm actually more interested in a place where I can register my company with prospects of becoming full-fledged citizen in the future, preferably in somewhat colder regions of the planet. I'm not entirely happy with my current passport, and working out of off-shores doesn't do much good for that.
visarga 14 hours ago 1 reply      
Pleased to find my city - Bucharest - at the top of bandwidth and pretty decent with regard to living cost, but 1312 EUR/month is absurd. I'd estimate the living cost to $250 rent, $200 food, $20 internet and $20 mobile voice+data = about $500/month. That is, if you rent a flat, buy food at supermarkets, not if you spend all day in coffee shops and eat only at restaurants.
istorical 14 hours ago 0 replies      
Hey guys I'm also building a similar service to this site, but more focused on the qualitative than the quantitative:


angerman 19 hours ago 0 replies      
Ok. The idea is great, but as other have also said, the figures seem way off. Just two examples:

Basel being cheaper than Berlin? I have a hard time believing that.


Hong Kong being cheaper than Leipzig? That just can't be true.

tom_devref 17 hours ago 1 reply      
What if you prefer colder climates? Not sure why the city should be penalized for it. High temperatures make me less productive.
codingdave 15 hours ago 1 reply      
I get that this is made for short-term stays, and being truly nomadic. But I think many of us who work remotely do it to allow us to leave the cities. Building permanent roots in a small town is way cheaper and simpler, but that isn't really covered here.

Also, one's own goals and personality have a lot more to do with the "best" place to work from than the crunchable data does.

So I like the idea of compiling a list of great places to work remotely, but I'm not sure this particular execution of that idea has a ton of value for me.

jwblackwell 16 hours ago 0 replies      
Love this! But I'm surprised not to see main Spanish cities on here. I took a short trip to Seville and was amazed how cheap everything was (I live in London).

There was an abundance of Airbnb accommodation, eating out was cheap and you could get a bucket of beers for 5 euros in many places. About the same as a pint in London.

I'd make this list a little more interactive, perhaps have a forum/comments behind each city. Could become a really useful resource.

67726e 18 hours ago 2 replies      
Are there any good resources in getting the appropriate visa/permit to work in foreign countries? I just got the go-ahead to work remote and I'm looking into working abroad, but information on remote working and the appropriate visas seem few and far in between.

To those that have done it, where do you look/who do you ask when looking for this type of information? Do you just get ahold of someone at the appropriate embassy/consulate or is there some service you can pay for to assist with the process?

homakov 14 hours ago 0 replies      
You should also add "Visa" field. E.g. any american can live in Europe up to 3 months, but in Thailand it's just 1 m.

I lived in Bangkok for about a year, thought I love that city, now their visa policy got stupid, and I would't recommend to settle there for long period (>3 months).

noeltock 20 hours ago 0 replies      
I like the concept for getting some new ideas, but it needs significantly more information to be useful downstream. Having been nomading around for the past year, there are things that are important to me (accomodation, gym, coworking, good food) that are made easier/harder by various factors (proximity to each other, cost, contract length, quality, etc.). There's no tool for that yet (albeit excellent blog posts, not everything has to be made into an app I guess).
vog 19 hours ago 1 reply      
I find it confusing that 1C is displayed in red, but 31C is displayed in green (instead of bold red).

The temperature should be checked against an upper limit.

fauigerzigerk 19 hours ago 0 replies      
Those european rent prices seem like a complete fantasy in some cases. Sure you get all kinds of outliers in every city but rents in Paris, Dublin and Berlin are certainly not the same. Paris is twice as expensive as Berlin, and Dublin is somewhere in the middle.

This site has much more realistic numbers: http://www.numbeo.com/common/

davidw 19 hours ago 1 reply      

Yuck. Worst city in Italy: it's expensive, polluted, crowded, and has little of what makes Italy so nice in many other places.

Italians move there because it's the business capital of the country, and there are jobs and money. But if you can live anywhere with a decent connection... that's the last place I'd go.

splitforce 11 hours ago 0 replies      
Next step is to take some input about user preferences and generate a personalized ranking of places to go. Here's a quick stab at building a 'personalized' desirability index: https://docs.google.com/a/splitforce.com/spreadsheets/d/1u-6...
hazelnut 14 hours ago 3 replies      
Great idea, but I can't find any information about healthcare?

It might be great to live in Thailand where you have to spent just a little for living but what happens if we compare this with their healthcare system?

scriptdevil 15 hours ago 2 replies      
It misses Bangalore, India. You could live a good life for $750.00 a month. For an additional $35 a month, you can get a 60MBps internet connection. Weather is pretty pleasant throughout the year. You could sample quite an assortment of cuisines too. Meetups are fairly active as well.Negatives: Traffic is terrible, but I stay indoors most of the time. Vendors do not speak English, but the number of non-Indians is high and the one can speak in English in any mid-sized shop.Disclaimer: I am an Indian, but am not a native of Bangalore. I was initially resentful of having to stay in Bangalore, but of late have started liking the city.
narrator 13 hours ago 1 reply      
Anyone listen to the "Travel Like A Boss" podcast? It's done by a guy living in Chang Mai Thailand. He mainly interviews dropship entrepreneurs. It's crazy because they are making $1500/month running these crappy little niche dropshipping stores but living like someone making $10000/month or more in San Francisco. They have maid service, live in full service buildings with rooftop pools, eat out all the time. It's crazy how cheap things are over there.
fookyong 19 hours ago 4 replies      
To those in this thread saying you need an appropriate working visa to work in these countries:

Have you ever worked for a company in Country A and been sent on a business trip to Country B? Most likely your company didn't need a Country B working visa for you, just for a business trip.

I am not a lawyer, but I don't see how the digital nomad lifestyle is any different. If you're just spending short amounts of time in these countries, legally how is this any different from going on a business trip since your company and salary will be paid in the origin country.

I'm sure there's a cut off point, like once you go over a certain amount of time it becomes harder to justify your trip as a short term business trip... but what's that line?

tet 18 hours ago 1 reply      
Bucharest ~ $1800 is exaggerated, honestly, if you live alone $500 are more than enough.
bdickason 16 hours ago 1 reply      
This is a great idea. I've been working from Sardegna (an island off the coast of Italy/Spain) and have barely been able to hold a skype connection to my office in NYC, even from most big cities.

I would have loved if someone went through and found great internet spots in each city (and even out in the country in some tourist-y spots) in advance so I could follow in their footsteps!!

Even at the least - letting me know that Vodafone is the best connectivity in the South, but sketchy in the northeast.

wingerlang 19 hours ago 0 replies      
I've lived in Bangkok the last 7 months and I spend approximately half the stated sum.

I am by no chance saying that the sum is invalid, it is probably pretty damn accurate (from what I've heard elsewhere).

Just mentioning that it is not the minimum. Not even I am at the minimum because I have a /relatively/ expensive apartment. And I don't live on breadcrumbs or anything like that :)

EDIT: As the reply posted by OP saying

> NomadCost is based on short-term staying in a hostel, hotel or apartment in the center, working in a coworking space and having a basic meal three times a day.

(I am not really close to that actual lifestyle)

pvnick 8 hours ago 0 replies      
Bookmarked. You may not see this comment, but I'm planning to travel and work remotely for a couple years after I graduate at the end of the year, and I think something like this will help a lot. Thank you!
micro_cam 17 hours ago 1 reply      
Very cool. To broaden the appeal I would consider expanding to include things like recreational opportunities. I spent some time road tripping around the us rock climbing and working remotely and know others who have done the same.

Knowing which small towns near climbing areas (or ski areas, or whitewater rivers, or national parks, or whatever) have reasonable coffee shops, hostels, camping etc would have been very valuable.

I guess some of this could be done by integrating a wiki or something.

TwiztidK 16 hours ago 4 replies      
This comment will probably get overlooked, but how do you get into the "digital nomad" lifestyle? Basically, what kind of work allows you operate 100% remotely? Thanks.
dewey 20 hours ago 1 reply      
Small bug:

I'm not able to switch the currency, it just shows pounds even though I selected Euro in the dropdown menu at the top (http://nomadlist.io/?l=eu)

danesparza 15 hours ago 1 reply      
I love the idea.

I notice that the only factors used don't seem to mention any political unrest. For example, the top rated city seems to be in Thailand... which has experienced a lot of political unrest recently: http://en.wikipedia.org/wiki/Thailand#2013.E2.80.932014_poli...

woutr_be 20 hours ago 2 replies      
A lot of these cities are only good if you are a local, for example in Hong Kong it is almost impossible to get a working visa that allows you to work for a remote company.I image in Japan it would probably be even harder.
randomflavor 18 hours ago 1 reply      
Local main language should be included?
dzhiurgis 15 hours ago 0 replies      
Great initiative, but I would add more smaller cities. Also temperature should have some sort of average. Surely it's not great to live in a scorching heat all the time.

That said, I dream one day to work remotely from a live aboard sailboat. Connectivity could be somewhat a problem, but 3G covers a lot of globe and if you are smart enough, living aboard can be very cheap.

dm2 19 hours ago 1 reply      
Why would being in the center of the city be important? I would think average anywhere in the city would be more reasonable.

I would also like to see the costs of a 2 bedroom apartment. I'd personally rather have an office in my apartment than a co-op space.

What would the price of a small house be within 10 miles of the city? (question that could be added)

How is the NomadCost calculated? These numbers don't add up: http://nomadlist.io/?hn

product50 19 hours ago 1 reply      
For working remotely, another factor which should be considered is time zone. It is very difficult to have a fruitful arrangement if you are always trying to scramble for times in the wee hours..
tiatia 19 hours ago 3 replies      
I don't see this as very useful. People are different, so are countries. Internet is very relative. Can be extremely slow and extremely fast in one city. Beijing 20 MBPS? Really? Maybe when you are torrenting or using Baidu. The Eardex Index http://flyingdutchman.co/cost-living-world-wide-county/ provides more info. But even this is like selecting you girl friend based on numbers.
jeremyirony 19 hours ago 3 replies      
Kek, since when Israel is in Europe?
alessioalex 20 hours ago 1 reply      
Bucharest is way undervalued. The internet speed can easily be 1Gb/s for around 15$ I think, while the montly costs for living should be around 1000$ at most in my opionion.
AliAdams 8 hours ago 0 replies      
I'm not sure where the data is coming from but I'm not convinced Bangkok is worthy of 5/5 stars for safety at the moment.
skrebbel 20 hours ago 2 replies      
Nice! I have some reservations about some of the data though; f.ex. I have a hard time to believe that SF has only slightly higher costs of living than Berlin.
chenster 14 hours ago 1 reply      
Taipei is my top choice. The healthcare is excellent (and free) if you are a Taiwan resident.
benwoodward 5 hours ago 0 replies      
What do the points in the left-most column represent?
espitia 14 hours ago 0 replies      
Awesome project! I've passed by many of the cities mentioned in Asia and I have to agree with most of what is up on top of the list. Specially Chiang Mai. I spent a 2 weeks up there and enjoyed it a lot. Met a lot of great people as well.
wnscooke 13 hours ago 0 replies      
There have been some suggestions to add more about visas... the true nomad really should be getting that information as directly as possible and not relying on a website like this, however helpful and handy it is.
gdilla 16 hours ago 0 replies      
This is great! Request - could you add the ability to choose your city and normalize the others? Example, I live in NYC, and I want to consider a move, how much cheaper is it? So if NYC cost is normalized to 1, then I can quickly understand the relationship to other places.
simonebrunozzi 14 hours ago 0 replies      
I am not able to add a city - I can open the spreadsheet but it's not editable.
riffraff 19 hours ago 0 replies      
I honestly cannot imagine how you may end up spending 2000$/month to live in budapest.

I got by with 400 for years.

thom_nic 17 hours ago 1 reply      
I would think crime rate should factor into this as well. It's at least as important as weather.
hal9000xp 20 hours ago 2 replies      
Good idea! But you have to add a visa information for each country.

For example, I like Hong Kong, but you can't stay there more than 2 weeks (if you want stay more, you have to get work permit/get married/have business there etc).

But Thailand afaik is easy country for living for a long time without work permit.

megablast 19 hours ago 1 reply      
Vang Vieng in Laos was the cheapest place I lived. Less than A$10 a day for hotel with my own room, internet, food and drinks. And it was a really beautiful place. All the restaurants had wifi, so you could sit and work there all day, overlooking amazing limestone cliffs.
dalerus 19 hours ago 1 reply      
Added Phnom Penh to your list.

If you're a remote worker it's great place. In the city most people speak English, huge expat community, USD is the main currency, stable internet, a few co-working spaces, amazingly cheap to live, and a business visa is no problem.

abuteau 17 hours ago 0 replies      
Sidenote: http://teleport.org/ Try to do something like that, but not crowdsourced. It's from Sten Tamkivi a16z entrepreneur in residence.
elwell 13 hours ago 0 replies      
The differentiation between [click to view larger photo] and [click text to go to city's page] threw me off for a few minutes.
radikal_shit 13 hours ago 0 replies      
Could you, please, add option tochange temperature view to Celsiusand integrate option to recalculate $ toseveral major currencies?
lolizbak 20 hours ago 1 reply      
Great work. How can people act on the info on specific cities ? There should be a way to balance wrong/right/... for variables that are subjective (weather, friendliness to foreigners, ....
itisbiz 13 hours ago 0 replies      
Nice, I like the grid presentation. Looks Bootstrap responsive table? What are you using for the column sort?
billrobertson42 18 hours ago 1 reply      
Some of the text is so low-contrast that I can't read it.
nrzuk 20 hours ago 0 replies      
Very nice :)Hopefully packing up in a months time and starting to work remotely so a list like this will certainly come in handy when investigating the next stop!
Dewie 18 hours ago 0 replies      
Using Fahrenheit (the degrees column for each city) as a measurement isn't very international.
progx 18 hours ago 0 replies      
I was wondering when you have time to work, most of the time you travel and seeking hotels, internet, startups, ...
wasyl 20 hours ago 3 replies      
Costs of living are definitely way off, I live in Wroclaw, you can easily live comfortably for $1000, probably even less
adamzerner 15 hours ago 0 replies      
What are the important cultural differences between Chiang Mai and, say New York?
mmanfrin 13 hours ago 0 replies      
SF is 3/5 for safety? Where's that metric coming from.
noahtkoch 18 hours ago 1 reply      
Damn dude, nice work, I've been following your developments on /r/digitalnomads
pistoriusp 16 hours ago 0 replies      
The HackerNews logo in the footer is also really pretty, did you also make that?
patmcguire 14 hours ago 0 replies      
I'm calling nonsense on Omaha costing more than Tokyo.
lotsofcows 16 hours ago 0 replies      
Nice. Although I'd write the first four off on temperature alone...
coppolaemilio 20 hours ago 11 replies      
Chiang Mai? You clearly haven't been there!It's nice for a holiday but not for living.
wslh 19 hours ago 2 replies      
You can live in Buenos Aires for half the price in the nomad list.
rockdiesel 13 hours ago 0 replies      
How is Omaha more expensive than Tokyo?
jeromegv 18 hours ago 3 replies      
Anybody can vouch for Philippines? Which city is the best?
dberglu 16 hours ago 0 replies      
Awesome idea -- Tim Ferris would love it.
tanmay007 16 hours ago 0 replies      
This is going to be so useful!
motormanwrithes 17 hours ago 0 replies      
super useful resource I'm sure, and I'd like to chat ideas to monetize, or at least capitalize on the knowledge too.

Is it cool to share this?

@motormanwrithes MANILA - LONDON - LA

SchizoDuckie 16 hours ago 0 replies      
I'm sorry but 2950 for living in Amsterdam for a month, that's insane.
adammcnamara 15 hours ago 0 replies      
Thanks for sharing.
AlexNeoNomad 16 hours ago 0 replies      
I knew that Chiang Mai would've been there surely.
jahitr 18 hours ago 0 replies      
Those numbers are all made up.
Sublevel A personal network
27 points by davidbarker  7 hours ago   25 comments top 14
voltagex_ 6 hours ago 2 replies      
So many words to say so little. What is this about? Is it closer to app.net or to OwnCloud? Why would I choose this over Twitter, Tumblr, Facebook, Blogger or Medium?
prawn 6 hours ago 1 reply      
Made me wonder about a Twitter-style social network where you were the only human, and you knew it. Those that gradually followed and interacted with you were all bots mimicking humans, but for once not spamming or with an ulterior motive. Your content would never be seen by anyone else.

The bots would arrive to compliment, question and challenge you.

Would people care that they weren't real? Outside of the friends we know on Twitter now, do we know which of the rest are definitely real anyway?

Sounds a bit crazy, but just wondering if people will reach a point where they interact with bots and don't care if they give them what they want in terms of attention and validation.

dmix 4 hours ago 0 replies      
They desperately need a copywriter. This is classic meaningless brand copy, full of platitudes.
serf 6 hours ago 0 replies      
All I took away from from the page was the color codes for if I want to advertise for them, whoever it/they is/was/plans to be.
gregschlom 6 hours ago 0 replies      
I came to the comments to see if somebody could explain what this thing is about. Seems like I'm not the only one not getting it...

Feedback for the author: your marketing copy needs to explain clearly what your product does.

rdl 1 hour ago 0 replies      
Even after reading the comments here too, I still have no idea what this is supposed to be.
metabren 4 hours ago 2 replies      
"Sublevel is to Twitter what Pinboard is to Delicious, Reddit to Digg, Linux to Windows, Android to iOS, etc."


est 36 minutes ago 0 replies      
Need gravatar.
RossM 6 hours ago 0 replies      
I like the advertising strategy - one unobtrusive ad for everyone, for a whole week. The free charity ads are a nice touch too.

It's either going to stick in your head out of persistence (perhaps subconsciously) or get mentally blocked (though I'd bet on the former).

personjerry 3 hours ago 0 replies      
I looked at the front page and got no info about what it actually and lost interest.
chrislloyd 6 hours ago 0 replies      
It said "All you have to do is just write." so I started typing something and it didn't do anything.
olh 6 hours ago 0 replies      
I am pretty sure this is satire.
rjurney 6 hours ago 0 replies      
The value is subconscious.
eigenrick 4 hours ago 0 replies      
"Sublevel is made for people like you"

No it isn't. I run Linux :(

Tor security advisory: relay early traffic confirmation attack
173 points by ohmygodel  21 hours ago   43 comments top 6
scottalpert 15 hours ago 1 reply      
First rule of security: There is no perfect security. You need a multilayered strategy. Tor is a start. Anonymized OSs like Tails are another aspect. Not releasing personal info on the web -- to the extent you can do that -- is another.
Udo 15 hours ago 5 replies      
Is this problem even solvable on a fundamental level?

Of course, they can work on preventing nodes forwarding hidden header information, but an entity with global network insight will always be able to correlate users by the timing of their transmissions alone.

The introduction of malicious nodes is a workable option for lesser players. But hidden in the realtime nature of the Tor network is always the possibility of deanonymizing users if you're a powerful agency that can afford to inspect a sufficiently large part of all network traffic - they don't even have to run any nodes themselves.

mike-cardwell 18 hours ago 0 replies      
"So if the attack was a research project (i.e. not intentionally malicious), it was deployed in an irresponsible way because it puts users at risk indefinitely into the future."
higherpurpose 19 hours ago 3 replies      
I'm disappointed nobody has "leaked" the research so far. If they cared enough to research it in academia, surely they know it's important enough for Tor developers to know about the type of attacks they were performing, despite what any government officials might say? At least some hints should be leaked, if not the whole research.
opendais 16 hours ago 2 replies      
It sounds like to be truly safe you need to know safe entry guard node(s) and/or operate your own group of entry relays. Otherwise, you risk X% of your traffic potentially being deanonymized by someone controlling both ends.

Of course, if you do that, you probably need to remain constantly connected and moving data through Tor 24/7 to prevent any kind of analysis since you can't hide the fact you:

A) Control the relay you connect to.

B) Are connected to Tor.

infinity0 19 hours ago 2 replies      
Please will a mod rename the title? The blog post explicitly says (at the bottom) that we don't know if this is the Black Hat talk that got cancelled early.
Poorly Managed HealthCare.gov Construction Cost $840M, Watchdog Finds
52 points by malchow  3 hours ago   56 comments top 10
brandonb 2 hours ago 1 reply      
I was part of the "tech surge" brought in to help patch up healthcare.gov in December. The GAO report gives a decent idea of what went wrong in 2010-2013 from a high-level contracting and policy perspective, but it doesn't really give much technical detail or describe what was broken about the organization, software architecture, and culture.

A couple of my colleagues have given talks on healthcare.gov from the perspective of the engineers who worked around the clock to help get the site running again: http://youtu.be/0albm_hhQzM?t=3m40s http://www.youtube.com/watch?v=GLQyj-kBRdo

A small team is also re-writing the site, starting with the most troublesome components for the next open enrollment period. Wired covered some of what is going on here: http://www.wired.com/2014/06/healthcare-gov-revamp/

If any of you out there want to help, please email jobs@hcgov.us!

vnchr 2 hours ago 1 reply      
Consulting firms like Deloitte were taking payments of +$70 million[1] to do "analysis" that "informed development and decision making." The associated waste of resources is unfathomable in the startup world but seems to be common with federal contracting.

1. Tipsy Deloitte associate chatting at a Chicago bar

Ecio78 2 hours ago 0 replies      
Each time I read about this I think about our dear Italian tourism portal www.italia.it that costed us more than 58mil in 2004-2008 and was a huge failure. According to wikipedia[1] we have then spent additional 10mil for redoing it, plus 20mil for managing it in these years.Interesting for the HN designers is probably the "nice" logo[2] that won a 100.000Euro logo competition in 2006 (it was created by Landor, a US or UK brand design company...)There were jokes about the green "t" that looked like a cucumber (and in Italy the cucumber - "il cetriolo" - has sometimes a double meaning)..

[1] http://it.wikipedia.org/wiki/Italia.it[2] http://www.marcosansalone.com/creativeantblog/?p=310

known 6 minutes ago 0 replies      
Mediawiki is better for storing/retrieving UNSTRUCTURED data
malchow 3 hours ago 0 replies      
Here is the full testimony to be delivered tomorrow: http://docs.house.gov/meetings/IF/IF02/20140731/102587/HHRG-...
Acen 2 hours ago 1 reply      
Is there a way to bypass the pay wall to read this?
alien3d 2 hours ago 0 replies      
Wow.quite cheap...
Daishiman 2 hours ago 5 replies      
Is it me or is that not that much money for a system that serves a 350 million-person nation?
sytelus 1 hour ago 0 replies      
This number may look big but remember average per head cost of a software engineer is about 230K/yr. Any software project that takes 3 years and requires ~1000 engineers would approximately cost similar amount.

On the side, I'd first hand experience with healthcare.gov to help someone else. I can imagine myriads of integration points between insurance companies, keeping track of their plans, state level requirements, credit checks, other govt agencies like social security, customer service backend etc. From my experience in working with this kind of complexities I think 200-300 engineers may be more than enough for 2 year execution plan. So still it's about 3X-4X waste when government gets involved.

PS: Per head cost needs to include base salary + bonuses + stock grants + hiring fees + employee events + office expenses + subsidized cafeteria + health benefits + 401K etc etc.

colmmacc 1 hour ago 2 replies      
Maybe this is facile, maybe it is illustrative, but I find it interesting to compare HealthCare.gov and Twitter. Twitter has raised over a billion in funding so far, has been going 8 years and has over 3,000 employees.

Healthcare.gov is at about 3 years, $840M, and I can't find a number for how many people were involved, but it's likely also in the thousands. Healthcare.gov has delivered life-altering value to about 6 million people and cost about $150 per user (soon amortizable over at least two years). Twitter has about 200 million active users getting everything from minor titillation to revolutionary aid and has cost about $6 per user. Neither of those "prices" seems shocking to me, and I'd pay $6 to use twitter and $150 to use Healthcare.gov.

If anything, healthcare.gov seems cheap in that context. In terms of scale of effort; if I took a cursory look at twitter's functionality, and even taking scale into account [1], I'd spitball it as taking maybe 3 or 4 small dev teams for the website and API, and another dev team per app; maybe 100 engineers total. I'm sure they have more than that though; because a cursory spitball guess is an insult and there's likely a lot of hidden complexity and business logic discovered only you if try to do something like twitter very well. I'm also sure there's a huge mass of employees dedicated to wet, human, problems too like sales acquisition and support and what direction the shading should be on the twitter eggs and why the logo should just be a bird.

And so it likely is with Healthcare.gov, interfacing with hundreds of different healthcare providers, handling different administrations and so on; probably a real deep mess. I'm impressed they got it working at all; especially as when they set out it was never intended to be used much (as I understand it the idea was that the state exchanges would handle the larger burden). The frontend seems to have been shoddy, but how much of the expense was that?

[1] I have built and operate services at the same scale as twitter.

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