Sustainable Energy – without the hot air

I’m currently reading through Sustainable Energy – without the hot air by David J.C. MacKay, FRS, which I recommend to anyone interested in energy or energy policy. I’m particularly impressed by the graphs and diagrams in the book, both for the laboriously-collected data they represent and for their power to convey important points quickly and clearly. (Example).

The visual imagery evoked by the prose is powerful too: in a section discussing the merits (and lack thereof) of having a large number of people make a small saving each, here is what MacKay has to say:

The “if-everyone” multiplying machine is a bad thing because it deflects people’s attention towards 25 million minnows instead of 25 million sharks. The mantra “Little changes can make a big difference” is bunkum, when applied to climate change and power. [link]

Recommended.

Citation: David J.C. MacKay. Sustainable Energy – without the hot air. UIT Cambridge, 2008. ISBN 978-0-9544529-3-3. Available free online from www.withouthotair.com.

The Dunbar Number

This post is a collection of links about the existence and consequences of the Dunbar number.

Wikipedia:

Dunbar’s number is a theoretical cognitive limit to the number of people with whom one can maintain stable social relationships. No precise value has been proposed for Dunbar’s number, but a commonly cited approximation is 150.

The Wall Street Journal:

there is reason to believe that the social-networking sites will enable their users to burst past Dunbar’s number for friends, just as humans have developed and harnessed technology to surpass their physical limits on speed, strength and the ability to process information.

The Economist:

What mainly goes up [in the number of Facebook contacts], therefore, is not the core network but the number of casual contacts that people track more passively. This corroborates Dr Marsden’s ideas about core networks, since even those Facebook users with the most friends communicate only with a relatively small number of them.

The Monkeysphere:

So how many monkeys would you have to own before you couldn’t remember their names? At what point, in your mind, do your beloved pets become just a faceless sea of monkey? Even though each one is every bit the monkey Slappy was, there’s a certain point where you will no longer really care if one of them dies.

Zhou, Sornette, Hill & Dunbar:

Using fractal analysis, we identify with high statistical confidence a discrete hierarchy of group sizes with a preferred scaling ratio close to 3: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3, 9, 27,…

Bruce Schneier:

The smallest, three to five, is a “clique”: the number of people from whom you would seek help in times of severe emotional distress. The twelve to 20 group is the “sympathy group”: people with which you have special ties. After that, 30 to 50 is the typical size of hunter-gatherer overnight camps, generally drawn from the same pool of 150 people. No matter what size company you work for, there are only about 150 people you consider to be “co-workers.” The 500-person group is the “megaband,” and the 1,500-person group is the “tribe.” Fifteen hundred is roughly the number of faces we can put names to, and the typical size of a hunter-gatherer society.

Steven Chu: “The Energy Problem and the Interplay between Basic and Applied Research”

US Secretary of Energy Steven Chu gave an interesting Compton Lecture at MIT on May 12, 2009, on how researchers can fit in with providing energy for a crowded world.

more about "Steven Chu: "The Energy Problem and t…", posted with vodpod

GreatBong on the Kolkata Knight Riders

From this heartfelt writeup from GreatBong on the Kolkata Knight Riders:

Then on days where we were playing among ourselves on the streets and there were not enough players to make teams, we would play by what was known as “lottery”. In this form of “gully cricket” every player essentially forms a “team of one” and all that was left to be determined was in which order we would bat (this would be the reverse order in which we would bowl). Everyone would field and he who made the most runs won.

So how was this order decided? Someone (let us call him A) would stand and the second person (let us call him person B) would hold his hand behind the first person in a way that A would not be able to see. B would then show a random number of fingers and A would call out a name from among those assembled. And the number represented by those fingers would then become the called out person’s batting position.

Thanks to the Knight Riders, I am once again in touch with my past in a way I never thought would be possible.

Leaving aside the zinger about KKR deciding their batting order using a random permutation algorithm, not only is the algorithm to obtain a secure permutation of the team’s batting order remarkable in its simplicity, the childlike political compromises that made such a permutation algorithm necessary in the first place are truly endearing. Those kids would bring a tear to Bruce Schneier’s eye.

Product review: Enso from Humanized

Executive summary: Any sufficiently advanced GUI is indistinguishable from a CLI.

People older than a certain age will recall the time when the only way to tell a computer what you wanted it to do was to type in stuff through a command line interface (CLI). So if you wanted a word count on a file, you typed wc filename and got the answers with no fluff. Then these kids came along with their graphical user interfaces (GUI) and persisted in believing that (among other things) opening the same file in a large and slow word processor and clicking on Tools | Word count was somehow more user-friendly than remembering commands like wc.

And where are we headed now? Watch this video about Enso (which is Japanese for circle) from Humanized, and you might almost believe that the future of a GUI is a CLI, perhaps a semantically aware CLI, but definitely some creature where you type commands (or start typing them anyway) instead of one where you point and click.

What’s Japanese for “full circle”?

That said, I downloaded and have used Enso for a few hours now, and it’s certainly got its uses. My first impressions are by and large positive.

On the plus side:

1. the caps lock-based interface is usable and not intrusive — I had feared that using the caps lock key would interfere with normal operation, but it’s not bad.
2. The calculator function is rather helpful, though currently limited to the four basic arithmetic operations with constant operands. It is reminiscent in functionality of the sagetex plugin for TeX and LaTeX, whose best use I have found is to write HOWTO documents for mathematics without typing the formula once and copy-pasting the results again. It’s probably helpful to think of Enso’s math abilities as a stripped down fast-response sagetex.
3. The spellchecker and the case-toggler are nice, but your use for them will be much less if you type a lot in Firefox (blog posts, comments, etc) and already have a spellchecker add-on and the LeetKey add-on installed. Enso will probably be more useful if you do a lot of typing outside a word processor or a browser.

On the minus side (for me at least):

1. I had a rude shock when (out of force of habit) I tried to exit Enso by holding caps lock and typing “quit”. Instead of quitting, Enso closed the application that was in the foreground! BE CAUTIOUS! Save all your work when you’re trying this thing out! This is not expected behavior for a habitual CLI-user, where if you type “quit” or “exit” you will only leave the command shell and be returned to the GUI. Perhaps “close” might be a better word than “quit” for closing other applications?
2. The commands available for the calculator cannot currently read arbitrary scientific expressions, even ones that can be done with the plain old Windows calculator in scientific mode, or those that be done by asking Google Calculator. Hopefully this will change in future.
3. It would be helpful if the user could switch between “replace the selected text with the result” and “append the result to the selected text” modes, particularly when writing math formulas in a document followed by their evaluations: the reader needs to see both the expression and the evaluated result.

Overall, the product looks promising, and I expect to find it more useful with a few more features and a little more extensibility.

BBC: Brain decline begins at 27. Help!

Sez the Beeb:

Mental powers start to dwindle at 27 after peaking at 22, marking the start of old age, US research suggests.

Start of old age? Thank you very much.

Seriously though, the article does indicate the need for more urgent research, citing the current incurability of dementia and Alzheimer’s.

Bremner, Bird and Fortune: Silly Money

Note: This post is intended largely for my own use as a placeholder to collect clips of Bremner, Bird & Fortune’s Silly Money: Where Did All The Money Go? — a 4-part miniseries that originally aired on Channel Four in November 2008, satirizing the financial crisis.

The LEGO Turing Machine

Via Shtetl-Optimized, here’s an excellent bit of computer science humor: the LEGO Turing machine, seen here in its natural habitat, computing away to the theme from The A-Team.

On Cooking, Human Evolution, Obesity, and Type II Diabetes

An interesting write-up over at The Economist on Richard Wrangham’s argument about the role of cooking in human evolution, which he reiterated at the 2009 AAAS Annual Meeting in Chicago. The orthodox view among the anthropology community seems to be that human brain size increased due to a shift in diet from vegetables to meat. Wrangham’s view is that it is the cooking of food rather than its origin which has influenced human brain size:

Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It denatures protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it.

On the face of it, it seems plausible. Cooked foods make more nutrients available, and would presumably require less chewing, reducing the size of the jaw and making more of the skull’s internal space available for the brain.

This is a more application-oriented twist:

Indeed, Dr Wrangham suspects the main cause of the modern epidemic of obesity is not overeating (which the evidence suggests—in America, at least—is a myth) but the rise of processed foods. These are softer, because that is what people prefer.

On a very unscientific level, I had suspected once that upma made with fine semolina was digested more quickly (and consequently felt less filling) than upma made with coarse cracked wheat. It is nice to learn that there is a scientific basis for that hypothesis.

Now: assuming that food habits are harder to change than foods themselves, would it be possible to make people gain less weight by making foods artificially rough? Could one make a taste-free coarse-particled edible powder (like a “magic food”) to sprinkle on (or mix with) soft creamy foods to make them digest more slowly? I’m not being facetious — if the food is grittier and rougher and takes longer to digest, the glycogen peak after a meal should be wider and shorter, and should presumably make a person less susceptible to diseases like Type II diabetes. One way to do this would be to eat naturally grittier and healthier foods (whole wheat flour instead of refined wheat flour for instance), but if one habitually eats foods that are too soft and easily digestible, could we add an antidigestive agent to the food to slow down the sugar rush?

Amazon Product Reviews as a Literary Art Form

There seems to be an online subculture that treats product reviews on Amazon.com as a literary art form and an outlet for creative writing urges. Consider these:

For Perry’s Chemical Engineers Handbook:

A riveting book from start to finish!, October 17, 1998

Perry has outdone himself once again. The seventh edition is even more of a show-stopper than the previous editions. I read this book from cover to cover in one sitting, unable to put it down for a moment, not even to relieve myself! The molecular weights were so accurate and the heats of reaction made my spine tingle. Once I reached the section discussing distillation and tray efficiencies I [k]new I was hooked. I won’t give away the ending but it’s definitely a shocker. Bravo to Mr. Perry’s and I am counting the days to the release of your 9th edition!

For Denon AKDL1 Dedicated Link Cable (a $500 Ethernet cable to connect your music system to your IP-based speakers) (via):

A caution to people buying these: if you do not follow the “directional markings” on the cables, your music will play backwards.

Another for the same product:

After I took delivery of my $500 Denon AKDL1 Cat-5 uber-cable, Al Gore was mysteriously drawn to my home, where he pronounced that Global Warming had been suspended in my vicinity. Additionally, my cars began achieving 200 mpg and I didn’t even need gasoline. I was able to put three grams of cat litter into the tank and drive forever.

One heck of a cable.

Didn’t notice any improvement in audio quality though.

For How to Avoid Huge Ships:

I’ve been plagued by huge ships all my life. Ever since I can remember. This book tells you all you need to know about avoiding these everyday hazards. Now I can come and go with complete freedom. Even my weekly shopping is a pleasure!

For A Million Random Digits with 100,000 Normal Deviates (as a point of interest, 24% of people who view the page for this book buy “Pride and Prejudice and Zombies: The Classic Regency Romance – Now with Ultraviolent Zombie Mayhem!” instead):

Such a terrific reference work! But with so many terrific random digits, it’s a shame they didn’t sort them, to make it easier to find the one you’re looking for.

Speaking of random, you just know that someone is going to compile all these reviews into a book and try to sell it on Amazon or eBay: