november 13, 2004
En lite längre länklista
Efter en längre tids lågbloggande krävs åter rengöring i Bloglines-tanken. För enkelhets skull har delar av informationstraverseringen lämnats ofullständig. Det kan här nämnas att vid slika lågbloggningstider tenderar aktiviteten på hakank's bloglines blog att öka. Möjligen förekommer det viss överlappning mellan bloggarna men det kan nog välvälliga läsare förlåta efter rimlig betänketid.
Edward L. Glaeser, Giacomo A. M. Ponzetto, Jesse M. Shapiro: Strategic Extremism: Why Republicans and Democrats Divide on Religious Values (PDF)
Party platforms differ sharply from one another, especially on issues with religious content, such as abortion or gay marriage. Religious extremism in the U.S. appears to be strategically targeted to win elections, since party platforms diverge significantly, while policy outcomes like abortion rates are not affected by changes in the governing party. Given the high returns from attracting the median voter, why do vote-maximizing politicians veer off into extremism? In this paper, we find that strategic extremism depends on an important intensive margin where politicians want to induce their core constituents to vote (or make donations) and the ability to target political messages towards those core constituents. Our model predicts that the political relevance of religious issues is highest when around one-half of the voting population attends church regularly. Using data from across the world and within the U.S., we indeed find a nonmonotonic relationship between religious extremism and religious attendance.
Wikipedia: Organic Poetry:
OrganicPoetry is a game for social transformation by bringing people together in a collaborative manner. While based on complex ideas in game theory, conflict resolution, social networking and control theory, the game is extremely simple, because the players make up the rules as they play along.
Summary: A powerful tool, OrganicPoetry can be used in political advocacy, and in bringing people and communities together for a cause, to seduce your lover, or just to have some non-competitive fun at a party.
Jämför gärna med Sheep are sprayed with words to create poetry
Wikipedia: Birthday paradox:
The birthday paradox states that if there are 23 people in a room then there is a slightly more than 50:50 chance that at least two of them will have the same birthday. For 60 or more people, the probability is greater than 99%. This is not a paradox in the sense of it leading to a logical contradiction; it is a paradox in the sense that it is a mathematical truth that contradicts common intuition. Most people estimate that the chance is much lower.
Marginal Revolution: Quantum Game Theory samt Quantum Game Theory, Revisited som sedan följdes av en rätt intensiv diskussion, se t.ex. backtrack-länkarna i anteckningarna.
Och se även Let the quantum games begin från Physics Web, oktober 2002.
Spelteori och terrorism
Foreign Dispatches: The Game Theory of Terrorism
en uppföljning på Sock Thief: Game Theory and Terrorism med lite länkar till papers, t.ex. Terrorism and Game Theory av Todd Sandler och Daniel G. Arce
Cornell News: Why thin, flat things rise and glide on the way down: physicists finally solve the falling-paper problem .
Papret som refereras är Jane Wang: "Falling Paper: Navier-Stokes Solutions, Model of Fluid Forces, and Center of Mass Elevation", Phys. Rev. Lett. *93*, 144501 (2004). En abstract finns här.
Blog-a-Bing: Don't trust me: I make use of people
Technologic: What are the Foundations for Trust in Online Interaction?
Was trust originally established because eBay instilled confidence by asserting rules of conduct for buyers and sellers? Were the requirements stipulated by the individual sellers on their auctions also responsible for establishing trust? Was it the promptness to email questions, the layout and presentation of the sales page, or the description of the item being sold that instilled confidence?
Charles Roxburgh Hidden flaws in Strategy (The McKinsey Quarterly, 2003 Number 2)
After nearly 40 years, the theory of business strategy is well developed and widely disseminated. Pioneering work by academics such as Michael E. Porter and Henry Mintzberg has established a rich literature on good strategy. Most senior executives have been trained in its principles, and large corporations have their own skilled strategy departments.
Yet the business world remains littered with examples of bad strategies. Why? What makes chief executives back them when so much know-how is available? Flawed analysis, excessive ambition, greed, and other corporate vices are possible causes, but this article doesn’t attempt to explore all of them. Rather, it looks at one contributing factor that affects every strategist: the human brain.
Catherine A. Johnson: Choosing people: the role of social capital in information seeking behaviour
It is an almost universal finding in studies investigating human information behaviour that people choose other people as their preferred source of information. An explanation for the use of people as information sources is that they are easier to approach than more formal sources and therefore are a least effort option. However there have been few studies that have investigated who the people chosen as information sources are and what their relationship to the information seeker is. This paper reports findings that come out of a larger investigation of the information seeking behaviour of a random sample of residents of Ulaanbaatar, Mongolia. Using the theory of social capital as a conceptual framework and the methods of social network analysis, this study investigated the relational factors associated with the choice of people as information sources. Results indicate that respondents chose people who had better resources than they had and were not well known by them. This suggests that respondents were deliberate in their choice of people information sources and therefore it is speculated that people are not necessarily the least effort option but may require considerable effort to seek out and consult.
Crossroads Dispatches: Blogs as Truth-Telling Networks
Connectedness: What is social capital and how do we measure it?
MathWorld: Seven Mathematical Tidbits
JUNG 1.5 har släppts.
JUNG provides a common and extendible language for the modeling, analysis, and visualization of data that can be represented as a graph or network. Features in this release include: new visualization features (updated VisualizationViewer, new PluggableRenderer, and SpringLayout to make them more flexible and powerful; take a look at PluggableRendererDemo), new clustering and ranking algorithms, new vertex mapping mechanisms, new ways of reporting and diagnosing constraint violations, numerous new decorators and predicates; a number of improvements in usability and function to existing classes (including GraphML and Pajek I/O), and a number of bug fixes, including extensive revisions to the Barabasi preferential-attachment graph generator. Also now using COLT 1.2 (whose new license requirements should free JUNG for use in commercial development) and Commons-Collections 3.1.
Se även JUNG: ett Java-ramverk för graf-/nätverksanalys.
Philip Ball: Trains get fluffy
Superfast trains of the future could glide over fluffy tracks like snowboarders over snow, say US researchers. The same principle could be used to develop low-friction, long-lived bearings for machinery with moving parts.
Explainer: Epidemics in Small Worlds
Craigs List Personals and the Market for Lemons
I think this model [George Ackerlof's Market for Lemons] relates really well to Craigs List personals. Because the norm is for personal posters not to post a picture on this site and very limited information about themselves, people who have above average appearences and personalities go elsewhere to find dates. The market quickly unravels and you end up with either a girl who can't find a man anywhere else with a man that treats her like shit, a man who can't get find a date anywhere else and finds a woman who treats him like shit, or you get two very low quality people who can't find dates anywhere else and end up together. Other dating sites where you post much more informaation and is much less anonymous have a chance of working better for those who don't want one of three possible matches. Even better is meeting somebody without the use of personal ads.
Kimmo Eriksson, Jonas Sjostrand, Pontus Strimling: Optimal stopping in a two-sided secretary problem
In the "secretary problem", well-known in the theory of optimal stopping, an employer is about to interview a maximum of N secretaries about which she has no prior information. Chow et al. proved that with an optimal strategy the expected rank of the chosen secretary tends to approximately 3.87.
We study a two-sided game-theoretic version of this optimal stopping problem, where men search for a woman to marry at the same time as women search for a man to marry. We find that in the unique subgame perfect equilibrium, the expected rank grows as the square root of N and that, surprisingly, the leading coefficient is exactly 1. We also discuss some possible variations.
"The Secretary Problem" kallas även "The Sultan's Dowry Problem". Se t.ex. The Secretary Problem.
Freshmeat: poker-eval 124.0
poker-eval is a C library to evaluate poker hands. The result of the evaluation for a given hand is a number. The general idea is that if the evalution of your hand is lower than the evaluation of the hand of your opponent, you lose. Many poker variants are supported (Draw, Holdem, Omaha, etc.) and more can be added. It is designed for speed so that it can be used within poker simulation software using either exhaustive exploration or Monte Carlo.
An Open Challenge to Nassim Taleb from Hamilton, en diskussion om och med Nassim Talem, bland annat om den trevliga boken Fooled by Randomness: The Hidden Role of Chance in Life and in the Markets. Se även Edge Learn to expect the Unexpected.
Skeptical Inquirer Volume 28, Number 5, September/October 2004
Jakob Nielsen: User Education Is Not the Answer to Security Problems
Frisim: Kod-sökmotorn Koders.com
Minding the Planet: Great Article on Psychohistory and Sociophysics -- Can We Predict Behavior?
Freedom to Tinker: Bad Protocol
Dan Wallach from Rice University was here on Monday and gave a talk on e-voting. One of the examples in his talk was interesting enough that I thought I would share it with you, both as an introductory example of how security analysts think, and as an illustration of how badly Diebold botched the design of their voting system.
Joi Ito: How not to make YAPSN
Arrow's theorem is one of the most influential discoveries in electoral theory.
George A. Miller The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information (klassiker från 1956)
Counting on the future
It's almost ten years since the most famous mathematical puzzle of all time – known as Fermat's Last Theorem - was solved after more than three centuries of tantalising and torturing the world's most gifted mathematicians. Now, two more major conundrums may be about to crumble. So is mathematics in a golden age or is it, in fact, in decline? If you listen to mathematicians, "both" may be the correct answer.
Posted by hakank at november 13, 2004 11:05 FM Posted to Diverse vetenskap