As most of you already know, Volkswagen was recently caught cheating on emission tests. But were they really alone in doing so? The EPA data shows some suspicious patterns.
Without getting too technical (in any case, the specifics are still unclear), there's a tradeoff between fuel efficiency, and NOx emissions. So for a given level of performance, the software that controls a modern diesel engine can be tuned so that it is more fuel efficient, but produces more NOx, or it can be tuned so that it is less fuel efficient, but produces less NOx.
Since Volkswagen had problems meeting the NOx standards in the US, they decided to introduce software that detected when an emission test was being performed, and tuned the engine so as to decrease NOx production, in the process potentially worsening fuel economy relative to regular driving conditions.
One possible outcome of this procedure is that the cars involved might actually have better fuel economy in real life conditions, than during …
One of my ongoing research projects is on the Mongol invasions. Doing some background research, I realized there's an interesting asymmetry between male and female rulers, in terms of available imperial sexual strategies.
Say that the Mongol hordes have just finished annexing another city along their ever expanding frontier. Let's call it Elbonia. In this case the local elite had the good sense to surrender peacefully, and accept the Mongols as their rightful overlords. Everybody knew that if they put up a fight, the Mongols would typically exterminate a significant proportion of the local population, and enslave the rest.
What did the Mongols want from Elbonia? Well first of all, obviously they didn't want the inhabitants to ever attack their other dominions, regardless of any preexisting local feuds which may have existed. Secondly, they wanted them to send them money or tradable goods regularly. And thirdly, they wanted them to furnish soldiers for use in their next cam…
Here's a fun technique. I think it's new, but if somebody else has already done this or something similar, please feel free to correct me. The technique allows you to
simulate very directional lighting even on days with so-so lighting, but
it does take a little bit of planning.
Let's say you're out and about shooting photos, and there's a light overcast/mixed cloudy sky. If you wait until a break in the clouds hits your subject, you can take photos like this one:
Decent, but nothing too spectacular. How could you make the lighting more dramatic? One option would be to mess around with levels or curves, but that's going lead to clipping of highlights and/or shadows, pretty soon. Like so:
So here's my idea. First you wait until the clouds move a bit and your subject is in shade. Then you take a SUPER boring picture like this one from exactly the same camera position. This photo has completely diffuse lighting and next to know threedimentionality: