Tag Archives: cost and benefit

On military bravery

All countries and armed groups emphasize the bravery of their soldiers for propaganda purposes. Such claims are made regardless of whether there is any actual valour. Going to a dangerous situation or even certain death is not necessarily courageous, in particular if there is no knowledge of the danger or no choice. Are sheep going into a slaughterhouse brave? They are calmly walking to certain death, after all. But usually this is not ascribed to courage, but to ignorance. Analogously, soldiers used in early tests of the physiological effects of radiation exposure who were marched through an area of a recent nuclear explosion are not considered brave. They did not know the cancer risk.

If there is no choice, which usually means there are only perilous choices, then putting oneself in danger is not usually accounted brave. Jumping out of a burning building offers a higher probability of survival, so people do it despite the substantial risk of falling to death. When a sufferer of a painful terminal disease chooses euthanasia, this early death is commonly not considered brave. Some cultures even believe suicide to be a sign of cowardice. If a military has a well organized system for catching deserters and administering the death penalty to them (and their family in some regimes), then a soldier charging enemy machineguns is merely maximizing his survival probability. The enemy might miss, the firing squad rarely does.

The greater the probability of victory for one’s own side, the less attractive desertion becomes, because being caught is more likely. This explains the propaganda emphasis on own victories and the punishment of “defeatist talk” in wartime. The greater the military advantage of a party in an armed conflict, the less bravery its soldiers need.

Genuine bravery exists, but it is rare. Evolution favours cowardly bullies who attack the weaker (prey) and run from the stronger (predators). People who face no compulsion to fight in a war and know the dangers, yet still join, are brave. Freedom fighters (insurgents from the other side’s viewpoint) against a dictator qualify. With the caveat that only joining the fight initially requires bravery – after that, losing would mean being tortured to death by the dictator, so continuing the war is the safer option. Similarly, volunteering for the military requires some bravery (the more the greater the likelihood of being sent into danger), but once military law applies, desertion is usually more dangerous than the duty.

Military courage is proved for those who start the war as a weaker side against a stronger, if a continuing peace is not a slow death. Peasant revolts were often driven by hunger, meaning the participants may have perceived the probability of death from starvation as higher than the probability of being killed by the aristocrats.

People who have never faced an informed choice between a safe and a dangerous option may be “latently brave”, in the sense that given such a choice, they may exhibit courage. They are not proved brave, however, until they have made the choice. There are likely to be some latently brave people in the world’s militaries and armed groups. Probably a greater percentage than among the general population.

There are some proven brave folks even in the militaries of powerful countries, but the proof requires knowingly choosing a dangerous option when there is no future punishment for cowardice. For example, when nobody would know of the choice.

A topical question is whether suicide terrorists and other fighting religious fanatics are brave. Their behaviour may be driven by the fear of punishment either in the afterlife or by their fellow fanatics. It may also be due to ignorance – believing in an afterlife is like believing that one cannot really die and thus the danger is not real. In both cases, no courage is required for choosing death.

The belief in the impossibility of dying may even be literal – W.E.B. Griffin had a story of a witch doctor convincing the fighters of his tribe that his magic had made them immune to bullets. Great was the fighters’ surprise later… Their charge with spears against guns was not due to bravery, however.

Research articles may have negative value

Falsified, plagiarized or plain junk research is not considered here. The effort of the author and the cost to the funders are considered sunk and similarly ignored.

After a research article is published, it may still have negative value for humanity. How is this possible if the cost of creating it is considered zero and the results are not junk? Doesn’t every discovery, however small, contribute a little to the corpus of knowledge? It does, but the cost it imposes on other researchers may outweigh this. Every publication increases the number of articles that researchers of related topics have to look at, however briefly, to write their literature review and check that their idea is not already taken. It may take a few seconds to read the title and decide that the article is irrelevant to one’s work, but this small cost is paid by many. If the publication makes a small enough contribution to knowledge, then the total cost to other academics outweighs the benefit from this contribution. The researchers whose time the article wasted could have done something useful with that time.

Optimizing a bike for commuting

The objective is to get from point A to point B every day, minimizing some combination of time, effort and cost. The objective is not to get exercise (in that case, take a longer route, make the bike heavier) or to win a sprint. If cost is not a concern, then of course get the best bike money can buy. It is still not obvious this should be the fastest road bike.

The total time spent on bike commuting includes maintenance, locking and unlocking the bike and any other unavoidable tasks. A high-end road bike with thin tires may save some time every day, but gets flat tires more frequently than a thick-tired mountain bike. Each occasion of a flat tire costs significant time, plus some money. The time cost occurs randomly, which for most people is worse than if it were predictable and could be scheduled.

Thin wheels get bent more easily than thick ones, again requiring maintenance. Thus the fastest commute is not achieved by the lightest, thinnest bike. Reliability is what influences both time and cost the most.

Wheel and tire width affects weight, aerodynamic resistance, rolling resistance, flat tire and wheel bend frequency and ride comfort. The lowest rolling resistance occurs when the tire pressure is such that vertical tire thickness drops 15% under load (F. Berto, Bicycle Quarterly Vol 5 No 1). Tire tread pattern has such a small effect on rolling resistance that it can be ignored for commuters. The tire thickness that minimizes rolling resistance is 22-23 mm (wheelenergy.com). The thinner the wheel and tire, the lower the aerodynamic resistance, but this effect is under 1% of effort, small enough to ignore for commuters (http://www.biketechreview.com/index.php/reviews/wheels/63-wheel-performance). Wheel weight and inertia have an even smaller effect.

The thicker the wheel, the less chance of it bending (other things equal – wheels of weak material or poor construction bend no matter what). More expensive wheels are on average stronger and lighter. The thicker the tire, the lower the probability of punctures and pinch flats. For a commuter, it is optimal to choose wheels and tires heavy and thick enough to never bend or get flats on normal roads (having some potholes, broken glass etc). In my experience, this means thicker than 25 mm road tires and thinner than 50 mm mountain bike tires.

Punctures are less likely than pinch flats even with 25 mm tires. Puncture probability can be further reduced with e.g. Kevlar-lined tires, which add less than 40 dollars to cost.

It sounds like I am advocating a hybrid bike – these have intermediate thickness wheels and tires and are supposedly designed for commuting. My experience with the one hybrid I tried (Apollo Trace 10) was very bad. Both wheels bent enough to hit the brakes in less than a month of half an hour per day riding and two spokes broke on the rear wheel. Looking closely at the wheel, the substandard manufacturing was obvious. My speculation is that hybrids may be low quality because they are marketed to people who on average are not bike fans, ride little and in flat road conditions. They thus cannot distinguish quality levels and may buy a bike mainly based on its flashy paint. Road and mountain bikes, on the other hand, may be bought by more knowledgeable customers. For these to sell, they may need some minimum reliability.

It would be good to have bicycle reliability statistics like there exist for cars. Then this would be the best source to base bike choice on, not recommendations from friends, forums or bike shops.

What matters for speed and ease of riding is first the fit of the bike to the rider and second the maintenance of the wheels and drive train. The weight and general flashiness of the bike are far less important.

I think that the best used bike for a given price is better than the best new for that price, because clueless customers go for new, and some people want to demonstrate their wealth by replacing their high quality used bike with new at short intervals. They sell a high quality used bike for cheap to make room in the garage. I got a great on a used bike: a like-new 2008 Giant OCR 1 for 350 AUD. But this is just one data point.

Economics to guide materials science

There are too many possible materials to test them all, or even simulate by computer. Materials scientists theorize what combinations of elements are likely to yield the desired properties, but still there are too many possibilities. One way to narrow the choice is to use economics.

If the goal of developing a material is to change the world or make money, the benefit of the invention must exceed the cost. The benefit comes from the improved characteristics of the material relative to existing alternatives. What the market is willing to pay for an improvement depends on its size. There may be a theoretical maximum for a property, or its historical rate of increase may be used to forecast the likely improvement. Once an approximate willingness to pay for a unit of the candidate invented material is known, this can be compared with its estimated cost.

Financial firms dealing in commodity futures forecast the prices of chemical elements over the likely commercialization time horizon. Only materials using a combination of elements that is cheap enough are commercially promising. Cheap enough means that the improved material must cost less per unit than the market is willing to pay for it. An expensive element can be used, but only in appropriately tiny quantity. The requirement that the bundle of elements cost less than some bound cuts down on the number of combinations that are worth testing. Similarly, the manufacturing method must be cheap enough, so some methods may be ignored.

The basic cost-benefit analysis is a simple idea, though the benefit estimation may be complicated in practice. Probably the companies producing various materials are already taking the potential cost and benefit of an innovation into account in their R&D, but academic materials scientists perhaps not. If the goal is to advance fundamental science and satisfy one’s curiosity, then the cost of the material may not be an issue. But for the world to use the material, it must be cheap enough.

A practical recommendation is for an application-oriented lab to put up a periodic table with the prices of the elements added. A spreadsheet with the prices of commodities can be used to calculate the cost of a candidate combination for a new material. Testing the candidates should proceed in the order of decreasing “profit” (benefit minus cost of the material). This profit is not necessarily the same as commercial profit, because the benefit may include its whole contribution to society, not just the revenue to the producer.