Connected Coordination: Network Structure and Group Coordination

Networks can affect a group’s ability to solve a coordination problem. We utilize laboratory experiments to study the conditions under which groups of subjects can solve coordination games. We investigate a variety of different network structures, and we also investigate coordination games with symmetric and asymmetric payoffs. Our results show that network connections facilitate coordination in both symmetric and asymmetric games. Most significantly, we find that increases in the number of network connections encourage coordination even when payoffs are highly asymmetric. These results shed light on the conditions that may facilitate coordination in real-world networks

The Challenge of Flexible Intelligence for Models of Human Behavior

Game theoretic predictions about equilibrium behavior depend upon assumptions of inflexibility of belief, of accord between belief and choice, and of choice across situations that share a game-theoretic structure. However, researchers rarely possess any knowledge of the actual beliefs of subjects, and rarely compare how a subject behaves in settings that share game-theoretic structure but that differ in other respects. Our within-subject experiments utilize a belief elicitation mechanism, roughly similar to a prediction market, in a laboratory setting to identify subjects’ beliefs about other subjects’ choices and beliefs. These experiments additionally allow us to compare choices in different settings that have similar game-theoretic structure. We find first, as have others,that subjects’ choices in the Trust and related games are significantly different from the strategies that derive from subgame perfect Nash equilibrium principles. We show that, for individual subjects, there is considerable flexibility of choice and belief across similar tasks and that the relationship between belief and choice is similarly flexible. To improve our ability to predict human behavior, we must take account of the flexible nature of human belief and choice

Cheap, Easy, or Connected: The Conditions for Creating Group Coordination

In both legal and political settings there has been a push toward adopting institutions that encourage consensus. The key feature of these institutions is that they bring interested parties together to communicate with each other. Existing research about the success or failure of particular institutions is ambiguous. Therefore, we turn our attention to understanding the general conditions when consensus is achievable, and we test experimentally three crucial factors that affect a group\u27s ability to achieve consensus: (1) the difficulty of the problem, (2) the costs of communication, and (3) the structure of communication. Using multiple experimental approaches, we find that difficult problems impede consensus, costs make consensus less likely (even relatively very small costs), and the structure of communication has significant effects and interacts with both problem difficulty and costs. In particular, the structure of communication can reduce the negative effect of costs and facilitate consensus. Together these results imply that consensus is only likely to occur if problems are easy, costs to communicate are low, or the communication structure helps overcome the other two problems. These findings can provide insight about the institutional designs that can be utilized to promote consensual outcomes

Theory of rotational processes in perpendicular media and application to anisotropy measurement

Numerical and analytical calculations of rotational process in perpendicular recording media are presented. The work supports recent experimental studies that suggest that the measurement of rotational magnetization processes can be used to determine the value of the anisotropy constant. An expression for the rotational magnetization for a noninteracting system is derived taking into account the dispersion of K and the easy-axis orientation. The calculations show that the experiments determine the mean value of H-K, essentially independent of the angular dispersion. A numerical (Monte-Carlo based) micromagnetic model is used to study the effects of magnetostatic and exchange interactions at nonzero temperatures. It is shown that for small values of KV/kT, irreversible magnetization processes take place, which precludes the use of the rotational magnetization method to determine K values. This effect is enhanced by the presence of the magnetostatic interaction. However, the presence of exchange interactions is found to enforce coherent rotation in small fields, reducing the irreversible processes and allowing the determination of H-K. Under these circumstances, it is shown that the exchange does not significantly affect the value of HK, and that a well-defined demagnetization correction of 4piM is appropriate. Finally, a comparison with experimental data gives good agreement for multilayer and granular media and shows the role of domain formation on the rotational magnetization process

A learning object success story

This paper outlines an approach to designing a course entirely in learning objects. It provides a theoretical basis for the design and then presents evaluation data from a master’s level course using this design. It also describes several re-uses of the learning objects on other courses and in different contexts. Each learning object is conceived as a whole learning experience, thus avoiding many of the problems associated with assembling components of disparate kinds

Making Talk Cheap (and Problems Easy): How Legal and Political Institutions Can Facilitate Consensus

In many legal, political, and social settings, people must reach a consensus before particular outcomes can be achieved and failing to reach a consensus may be costly. In this article, we present a theory and conduct experiments that take into account the costs associated with communicating, as well as the difficulty of the decisions that groups make. We find that when there is even a small cost (relative to the potential benefit) associated with sending information to others and/or listening, groups are much less likely to reach a consensus, primarily because they are less willing to communicate with one another. We also find that difficult problems significantly reduce group members’ willingness to communicate with one another and, therefore, hinder their ability to reach a consensus

High-Speed, Photon Counting CCD Cameras for Astronomy

The design of electron multiplying CCD cameras require a very different approach from that appropriate for slow scan CCD operation. This paper describes the main problems in using electron multiplying CCDs for high-speed, photon counting applications in astronomy and how these may be substantially overcome. With careful design it is possible to operate the E2V Technologies L3CCDs at rates well in excess of that claimed by the manufacturer, and that levels of clock induced charge dramatically lower than those experienced with commercial cameras that need to operate at unity gain. Measurements of the performance of the E2V Technologies CCD201 operating at 26 MHz will be presented together with a guide to the effective reduction of clock induced charge levels. Examples of astronomical results obtained with our cameras are presented.Comment: 11 pages, 5 figure