I'm back from my 3-country tour that started with being guest of honour at Helsinki's "Alternative Party" which introduced me to the Demoscene, something I will write about in some future blog posts. While I have much to say about this trip, and many gigs of photos, I thought I would start with some travel notes.

The latest tome -- and at 900 pages, I mean tome -- from Neal Stephenson (author of Snow Crash, the Diamond Age and Cryptonomicon) is Anathem. I'm going to start with a more general review, then delve into deep spoilers after the jump.

This book is highly recommended, with the caveat that you must have an interest in philosophy and metaphysics to avoid being turned off by a few fairly large sections which involve complex debate on these topics. On the other hand, if you enjoy such exploration, this is the book for you.

Anathem is set on a planet which is not Earth, but is full of parallels to Earth. The culture is much older than ours, but not vastly more advanced because on this world scientists, mathematicians and philosophers live a cloistered life. They live in walled-off communities called Concents, with divisions within which only have contact with the outside world, and with each other, for one 10 day period out of each year, decade, century or millennium.

As such the Avout, as they are called, lead a simple life, mostly free of technology, devoted to higher learning. It's a non-religious parallel to monastic life. In the outside "saeclular" world, people live in a crass, consumer-oriented society both like and unlike ours.

I give the recommendation because he pulls this off really well. Anathem is a masterwork of world-building. You really get to identify with these mathematical monks and understand their life and worldview. He really builds a world that is different but understandable.

One way he does this, which does frustrate the reader at first, is through the creation of a lot of new coined terms. Some terms are used without introduction, some get a dictionary entry to help you into them. The terms are of course in a non-Earth language, but they are constructed from Latin and English roots, so they make sense to your brain. Soon you will find yourself using them.

So, if you like clever, complex worldbuilding and the worlds of science and philosophy, this book, long as it is, is worth it for you. However, I will shortly talk about the ending. Stephenson has a curse -- his world building is superb, and his skill at satisfying endings is not up to it. Anathem actually has a decently satisfying ending in many ways -- better than he has done before. There is both an ending to the plot, and some revelations at the very end which make you rethink all you have read before in the book. This time, I find fault with the consistency of the metaphysics, and mainly because I have explored the same topic myself and found it very difficult to make it work.

It's not too much of a spoiler to say that after we are shown this remarkable monastic world, events transpire to turn it all upside-down. You won't be disappointed, but I can't go further without getting into spoilers. You will also find spoilers in my contributions to the Anathem Wiki. That Wiki may be handy to you after you read the book to understand some of the complex components.

I've written a few times about the "Selfish Merge" problem. Recently, reading the new book Traffic: Why We Drive the Way We Do by Tom Vanderbilt, I came upon some new research that has changed and refined my thinking.

The selfish merge problem occurs when two lanes reduce to one. Typically, most people try to be "good" and merge early, and that leaves the right lane, which is ending, mostly vacant. So some people zoom ahead of everybody in the right lane, and then merge at the very end. This is selfish in the sense that butting into any line is selfish. Even if overall traffic flow is not reduced (and even if it is increased) the person butting in moves everybody back one slot so they can get ahead by many slots. This angers people and generates more counter-productive behaviour, including road rage, and attempts to straddle the lanes so that the selfish mergers can't move up to the merge point.

In Traffic, Vanderbilt writes of surprising research that changed his mind, which showed that, in simulations, some merging forms provided up to 15% more traffic throughput than proper attempts at a zipper merge. In particular, a non-selfish merge fully using the vanishing lane worked better than the typical butt-in situation described at the top.

In this merge, which I'll call the "slow and fair merge," drivers are told to use both lanes up to the merge-point, and then to fairly "take their turn" at the merge point entering the continuing lane. Nobody is selfish here, in that nobody butts ahead of anybody else, but both lanes are fully utilized up to the merge point.

This problem is complex, I believe, because there is a switch-over point, which I call the "collapse" point. This is the point at which the merge flow becomes high enough that traffic collapses to "stop and go" mode, before and at the merge-point. Before that point, in lighter traffic, there is little doubt (for reasons you will see below) that the "cooperating fast zipper" merge results in the best traffic flow. In particular, there are traffic volumes where you could either have cooperating zipper or "slow and fair" but cooperating zipper would do a fair bit better. There are also traffic volumes where cooperating zipper just isn't possible any more, and we will either have "slow and fair" (which has the best volume) or "selfish merge" which has a worse volume.

Real world experiments show different results from the theoretical. In particular, many drivers, used to the anarchic selfish-merge approach, don't understand fair and slow, even when signs are explicit about it, and so they resist using both lanes and try to merge early. They also try to straddle, devolving to selfish merge. An experiment with digital signs which changed from advising drivers to zipper-merge in light traffic to advising "use both lanes" and "merge here, take your turn" in heavier traffic was disobeyed in fair and slow mode by too many drivers. The experiment ended before people could learn the system.

I have tripods with both 3 segments and 4 segments. A 4-segment tripod has 3 clamps per leg, which means 9 of them to open and close in extending and collapsing the tripod. That's a pain. Enough of one that you sometimes find yourself asking whether a shot is worth setting up the tripod. But even 3 segment tripods are only a bit better.