Physics do not apply in the Star Wars universe.

I'm not just referencing Solo's "Kessel Run in less than 12 parsecs" claim, which can be explained away as a boast about navigational and piloting ability rather than ship speed. (Though there may be relativistic reasons for why speed would affect the ability to accomplish the Kessel Run in a shorter distance.)

In the latest BrickMaster (LEGO's magazine), there's a fake ad from Koensayr for the Y-Wing that claims "Goes from 0 to 2,700G in less than a parsec!" I was going to try and figure out what that meant, and then realized that 2,700G is acceleration and parsec is distance! When car manufacturers boast that a car goes from 0 to 60 in 4 seconds, what they are bragging about is acceleration, that within 4 seconds, the power is such that the car can be accelerated to 60 mph from rest. What the hell does 2,700G mean? (Besides the fact that G is meaningless in Star Wars unless it references a specific planet.) If we take G to be 10 m/s^2, then 2,700G = 27,000 m/s^2. At that acceleration, it would take about 7 seconds to accelerate to lightspeed. I'm fairly certain that's not possible in the X-Wing flightsim games. Hyperspeed, yes, STL acceleration, no way.

powerpoint parsing fail

Yesterday, I was puzzled by this curious bullet-point at our weekly ecology seminar:
- recruitment unlikely due to Allee effects

Because I was parsing "unlikely" as an adverb modifying the verb "due" - of course, this didn't make any sense because Allee effects are not typically mentioned except as a mechanism to inhibit recruitment. Even more confusing was the previous sentence that no significant recruitment had been observed since the 1960s - so in some ways the statement that there *was* recruitment could have been new evidence to overturn earlier findings.

Eventually, I figured out that the intended parsing was for "unlikely" to be an adjective modifying the noun "recruitment" - recruitment is unlikely to occur because of low population densities (Allee effects).

Which begs the question of using complete sentences vs. phrases in powerpoint bullets: in this case, I think a complete sentence would have been fairly unambiguous, and would only have needed to be a bit longer - but in other cases, a complete sentence would take up a lot more space and be confusing as a block of text for the audience to read.

You keep using that word [logic]: I do not think it means what you think it means.

From Francis Collins, who argues the following as scientific evidence for God:

An additional set of observations I found quite breathtaking and do to this day is the fact that the physical constants that determine the nature of interactions between matter and the way in which energy behaves have precisely the values they would need to have for any kind of complexity or life to occur.

I interpret the argument to be thus:
(1) the physical constants necessary to support life are extremely rare
(2) because the life exists, then God must exist.

I am skeptical that (1) is true, since we don't know ANYTHING about extraterrestrial life to say what could or could not be supported by different physical constants. It is outside our realm of knowledge to say that lifeform X could not exist under conditions Y because we don't know about all the different types of X or even all the different types of Y.

But for argument's sake, let's suppose you accept (1). Then you hit the BIG logical fallacy:

Because life exists (and the conditions to support life are astronomically rare), God must exist.

Which is completely ass-backwards, because the logical sequence of events is:

God exists => the physical constants of the universe are tuned perfectly => life exists.

Since we are alive, this statement CANNOT be disproven. It can only be disproven if we find (a) perfect tuning of physical constants of the universe and (b) the LACK of life. By definition, it would seem difficult to both determine the physical constants of the universe while not being alive and also proving that no life existed elsewhere in the universe.

This is an extremely basic logical fallacy that I learned about in 8th grade in the math unit on logic, but I'm sure I had an intuitive sense of why this was incorrect earlier than that. Claiming that this is "scientific evidence" for God is just plain BS, cuz last I checked *real* scientists (and scientists-to-be) use logic.

Fisheries, Finance, and Physics

[edited for clarity]

See what I did there with the phonetic alliteration? :)

Q. What is the difference between the LHC (Large Hadron Collider) and Banks?

A. Black holes created by the LHC are more transparent about where stuff goes...



One theory about the potential dangers associated with the LHC puts the risk of it destroying the Earth at 50-50 (watch the clip!). Of course, this must be qualified by examining the probability that this theory of assessing the risk of the LHC is correct (0%). Other estimates of the risk posed by the LHC suggest that the probability of destroying the Earth is at 10^-9. As Ord, HIllerbrand, & Sandberg rightly point out, this should be qualified by the possibility that the model is incorrect or that calculation errors have been made.

In most cases, it is impossible to gauge the failure probability for something like a single bolt on the space shuttle. In these cases, mathematical models are often used. Clearly, estimates of the probability of "rare" events need to take into account the possibilities that the models used to generate such probabilities are accurate.

Andy Haldane describes a similar problem with how the financial industry assessed risk: some of the initial events that sparked the issue were "unlikely"* Well, either we are extremely "lucky" or the model is incorrect. Unless you can demonstrate to me that the probability of the latter is less likely than seeing that kind of impossible event, I'm going to bet that someone somewhere screwed up. In fact, it's plain to see from Chart 1 of the notes for Haldane's speech how this could happen. In the chart, data collected over the last 10 years (1998-2007) suggested that the probability of negative GDP growth was, effectively, zero. Looking over the whole sample of time (1857-2007) in which this data has been collected, however, suggests that negative GDP growth occurs maybe 15% of the time. That doesn't seem like a big difference, but when you bet billions of dollars on what you think is a sure thing (non-negative GDP growth), but actually occurs maybe 1 in 7 times, that's an f-ing big risk.

What does this have to do with Fisheries, you ask. Well, according to the Magnuson-Stevens Act (yep, THAT Ted Stevens), "Conservation and management measures shall be based upon the best scientific information available.". I suppose this means that fishing should not be a level where there is a significant risk of collapse. (whatever significant means...) Of course, the estimation of collapse risk is done using a model, which is fallible, possibly with high probability. If your best available science is not very good, is that sufficient to go plowing (or trawling, I guess) ahead? Your "best" model may suggest that you can fish 100,000 tons per year with < 1% chance of collapse, but if your model is only ~80% accurate (which is really good for fisheries models!), the upper bound on the probability of actual collapse is closer to 21% (0.8 * 1% + 0.2 * x, where x is unknown, but up to 1, potentially).

Logic and stats are nice when they're applied correctly, but more often than not, their use is exaggerated. And part of the blame does rest on the shoulder of scientists, who necessarily play up their results to get funding/acclaim/jobs. Still, that *is* why we have scientists advising the government, right? So that government officials will be able to take the best information available to make decisions? (and then we cross our fingers that our elected officials (or their appointees) know enough to weigh information properly...)

* shifts on the order of 25 standard deviations, which Andy calculates to occur roughly once every 10^135 years or
1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 years.

1) Ord, T., Hillerbrand, R., & A. Sandberg. Probing the improbable: methodological challenges for risks with low probabilities and high stakes. [preprint] (2009).

2) Haldane, A.G. Why banks failed the stress test. [speech] (http://www.bankofengland.co.uk/publications/speeches/2009/speech374.pdf) (2009).

Why Carbon Sequestration is Probably a Bad Thing

The US Department of Energy is planning to start this week on a large-scale project for carbon sequestration in Illinois. So why is this a bad thing?

Well, let's suppose, in hypothetical candyland where government projects do what they are supposed to, without negative side effects, on-time and on-budget, that this project succeeds. Ok, good for us, we've removed CO2 from the atmosphere. I applaud your efforts DOE.

This does NOT solve the problem of rising energy needs. Rather, I believe the effect may even be in the opposite direction. Psychologically, the idea that CO2 emissions can be reduced "magically" will diminish efforts to change behavior to reduce CO2 emissions in the first place. And that IS a major problem. Fossil fuels WILL run out (or be hideously expensive) within a few decades at current rates of consumption (and growth in consumption). Running out of fossil fuels without the energy infrastructure to replace them is going to cause a major global crisis that will not be resolved easily. Not to mention, petroleum by-products (plastic) have vital uses and are even more important for a lot of products we commonly use.

Climate change is only one of the major global problems that needs to be addressed in the near future (i.e. this century). And CO2 emissions are only one facet of that problem. As reported by Arstechnica from the AAAS meeting, the numbers for replacing fossil-fuel energy production with "renewable" sources is already extremely daunting. The most economical/efficient way to address that problem is to tackle it from multiple directions: improved efficiency (less usage, less waste), increased production from "renewable" sources (e.g. solar, tidal, wind, etc.), and finally carbon-scrubbing to reduce CO2 concentrations back to pre-industrial levels (i.e. 280 ppm atmosphere, and slowly equilibrate the oceans to that level). Introducing a carbon sequestration project is putting the cart before the horse: we should be focusing on the SOURCE of the problem (energy consumption) rather than simply mitigating the aftereffects because it is the most publicly recognized facet of the problem.

But, in the end, I guess Congress is a lot better at punting the problem and buying time, than in spending preemptively to alleviate future problems. Unfortunately, I happen to be one of those young'uns who is going to end up paying for the mistakes of the past. (*cough* war on terror, social security, etc.)

Red Alert 3

may be worth getting. I think RA2 did a good job with the story with some strange quirks (dolphins? psychics?), even under the hands of EA (we miss you Westwood!).

Still, one wonders about the necessity of a third rotor on the Soviet Twinblade unit: http://www.ea.com/redalert/factions-soviets.jsp?id=Twinblade

In a standard helicopter, the tail rotor provides the necessary balance to the rotational counter-force generated by a single main rotor. Without a tail rotor (or an unbalanced one), when the rotor spins one way, the helicopter body should spin the other way. This is countered by the tail rotor which adds the necessary torque to counter this spinning. However, with 2 main rotors spinning in opposite directions, no tail rotor is necessary, since the rotational counter-force is canceled completely. Just look at the V-22 Osprey.

*sigh* I guess this is another instance of how when developers do research to make their games realistic, no one notices (because it's realistic), but when something goes wrong, people pick up on it.

Color

Partially inspired by this post, seen on Boing Boing, I pondered the naming of colors.

Specifically, if we have navy blue and army green, shouldn't there also be an air force red?  It only seems logical.

Well let it be known that I hereby claim the rights to the color known as "Airforce Red".  Crayola, have your lawyers give me a call, whenever you decide to expand to 256 colors.

Anime-induced epilepsy

Nowadays, it is fairly common to see a warning that appears before the opening sequence of an anime. For example, consider the following warning that precedes Minami-ke:

(Minami-ke is one of my favorite series of the fall season. The character-based comedy is very well done, and it doesn't seem like it's going to take a nosedive like Zetsubou Sensei.)

Ok, so what is the origin of such a warning. Well, when reading a book, it is advised to have a decent amount of light so as to not strain the eyes. However, because a television emits its own light, there is usually plenty of light to see what's going on in the TV. As far as distance is concerned, I don't think there is any real reason for keeping the attended region small on the retina, so much as ensuring that strain is not occurring due to focusing on a nearby object for an extended period of time. (Books are generally another story, because there is constant movement of the eyes, I think.)

I checked out some of my anime DVD's and wasn't able to find a warning, so presumably, it only happens for the Japanese television broadcast. One way to check my hypothesis would be to examine anime broadcasts recorded prior to 1997 and broadcasts made after 1997 to see if the presence of the warning jumps from zero to a high percentage.

To understand the origins of this warning, I think we need a trip back to 1997, when the now infamous "Dennō Senshi Porygon" (でんのうせんしポリゴン) episode of Pokémon was aired in Japan. At some point in the episode, an explosion occurs that results in flashing of bright red and blue lights at 12Hz for 6 sec total. (4 sec for most of the screen, and 2 sec for all of the screen) Of course, these are prime conditions for inducing photosensitive epilepsy: high contrast, red color (certain wavelengths work "better" than others), a frequency between 5 and 30 Hz, and flashing across a large portion of the visual field. The episode is now banned worldwide, and hundreds of Japanese children were treated for symptoms, although mass hysteria resulted in some 12,000 individuals reporting symptoms. You can find more details on wikipedia's articles for photosensitive epilepsy and Dennō Senshi Porygon. The large number of epileptic victims was probably due to the extreme popularity of Pokémon, a show whose primary audience falls right into the population that is most susceptible to photosensitive epilepsy. The "best" part of the story is that, in a stroke of pure stupidity, Japanese news programs that reported on the story later that day, replayed the scenes in question, sending a second round of epileptic victims to hospitals.

Ok, so what then, does the warning accomplish. By increasing distance to the television, the amount of visual field occupied by the television is decreased. Also, increasing ambient light decreases the resulting contrast of scenes presented. While these changes serve to alleviate the inducing of photosensitive epilepsy, it probably is not terribly important, as I'm sure television producers are now aware of the conditions to avoid so that viewers don't develop symptoms.

The PTL Synaesthetic Color Space

Because we don't have enough color spaces, I have come up with another one of my own. Relying on precise measurements of colors that are induced by tones of varying pitch, timbre, and loudness in sound-color synaesthetes, it should be possible to create an alternate color space. I don't believe that the same is possible using grapheme-color synaesthetes, because although such synaesthetes are, overall, more consistent in their synaesthesia, there is not good space for graphemes to begin with that will also provide for a smooth gradation of colors. Sound-color synaesthetes on the other hand, do appear to have smooth gradations, which should yield a pretty good mapping. In order to boost their consistency in color-matching, we just need to look for the ones that also have absolute pitch.

Social Networks

I attended Matthew Jackson's talk today on modeling social networks. Besides the obvious shortcomings of using models to simulate real-world phenomenon, it seems that there are some lessons to be learned after applying certain analysis techniques to real-world networks.

More specifically, the structure of a social network (connections and their weights) determines the speed of convergence for opinions (at least as abstracted by the model). This has some interesting ramifications in the two examples that Matthew provided.

In the first example (managers in a small firm), the influence (characterized by the final convergent opinion if only that individual had that opinion initially) of individuals varied significantly, and actually corresponding quite closely to the actual hierarchy of executives within the company (the CEO and vice-presidents all had high influences).

In the second example (teenagers in a high school), the visual representation clearly showed the a segregation of groups (mostly on the basis of race, at least that's what the coloring of the graph seemed to portray). This segregation seemed to limit the overall convergence, as the analysis indicated that the second-largest eigenvalue was 0.98. (in other words, in each cycle of opinion updating, the error for convergence decreased by 2%)

Matthew also discussed the conditions under which social networks could converge "wisely". Basically, if each individual had some initial state of belief that was randomly distributed but centered around the "truth", under what conditions would the social network converge to an "accurate" value of belief?

Essentially, the answer is: true democracy (surprised?). A key requirement is that no one individual has strong influence (otherwise the error in that individual's belief would propagate), and that large groups of people pay attention to a majority of individuals in the social network.

If we believe that this method of modeling real-life social networks approximates the ways in which actual social networks work, this poses a number of problems for disseminating accurate information. For example, if we take the case of HIV denialism, clearly the group of HIV denialists is not swayed by a majority of the world (who accurately believe it when *ALL* medical doctors agree that HIV causes AIDS). Moreover, this group includes some highly influential people, including some musical artists.

However, there may be some hope yet: given that real-life social networks are "flawed" in this manner, it only makes sense to use the tools we have rather than trying to dramatically alter the way in which society forms opinions. Wikipedia accomplishes this rather well, by establishing itself as a highly influential source of information, that maintains accuracy by receiving input from any and all users, thus allowing it to converge to an "accurate" state. In fact, since Wikipedia requires external sources to verify information, it removes the need for contributers to be randomly distributed with respect to their "accuracy". As individuals, we can seek to benefit society by establishing ourselves with high influence via maintaining popular blogs...