Analyzing Social Network Structures in the Iterated Prisoner's Dilemma with Choice and Refusal

The Iterated Prisoner's Dilemma with Choice and Refusal (IPD/CR) is an extension of the Iterated Prisoner's Dilemma with evolution that allows players to choose and to refuse their game partners. From individual behaviors, behavioral population structures emerge. In this report, we examine one particular IPD/CR environment and document the social network methods used to identify population behaviors found within this complex adaptive system. In contrast to the standard homogeneous population of nice cooperators, we have also found metastable populations of mixed strategies within this environment. In particular, the social networks of interesting populations and their evolution are examined.Comment: 37 pages, uuencoded gzip'd Postscript (1.1Mb when gunzip'd) also available via WWW at http://www.cs.wisc.edu/~smucker/ipd-cr/ipd-cr.htm

Agroterrorism and the Implications of Uncertainty Reduction Theory for Agricultural Communicators

As a consequence of various terrorist attacks on U.S. soil the vulnerability of American agriculture to an agro-terrorist attack has come into question. The objective of this paper is to view the threat of agroterrorism through the lens of uncertainty reduction theory and extend the original application of the theory from the realm of interpersonal communication to the mass communication level. We offer a brief overview of bioterrorism and agriculture and the general concepts of crisis communication and pre-crisis preparedness. We explain the relationship between the level of uncertainty and organizational crisis with the value of pre-crisis planning efforts. We show the importance of the agricultural communicator as a source of agricultural knowledge in the pre-crisis stage, which can contribute to reducing uncertainty following an agro-terrorist event

The Cow That Stole Christmas: Framing the First U.S. Mad Cow Crisis

The discovery of bovine spongiform encephalopathy (BSE) in the United States made an impact on the beef industry. Determining how the BSE outbreak was framed by the news media is significant because research indicates that media shape public perceptions. This study examined how several key newspapers framed the 2003 outbreak of BSE in the United States. Determining how the media framed this issue can help communicators ensure bias-free media coverage of similar issues in the future. The study followed established framing analysis categories identified from the literature. There were 149 articles identified in The Washington Post, The Seattle Times, and USA Today for investigation in this study. Findings showed that the BSE issue was framed as an industry crisis and that the tone of the articles and headlines portrayed the beef industry negatively. When compared to the other two newspapers, USA Today framed the issue differently, with economic calamity being the dominant frame. The most heavily cited sources in the articles were government officials. This study recommends that media professionals avoid framing an issue for the public, focusing instead on reporting news in an objective and unbiased manner. Further research is recommended to examine the impact of tone and frame on specific audiences

Before it Hits the Fan: Pre-Crisis Beef Producer Information Source Preferences

The purpose of this statewide study was to determine preferences for the sources of information beef producers in Oklahoma use and trust when they seek information about agriculture during a crisis. Participants in this study were randomly selected from a population of 48,000 beef producers in the Oklahoma. All 470 respondents completed a telephone survey conducted by the Oklahoma Agricultural Statistics Service (OASS). Descriptive statistics, t-tests, and cross tabulations were used to analyze the data. Producers preferred their veterinarians when seeking information about animal health issues and any agriculturally related crisis; and preferred to receive information through county extension publications. They also perceived the local veterinarian as the most trusted and reliable source of information available. The Oklahoma State University Cooperative Extension Service, through the county extension agents and the local area livestock specialists, and the USDA were also trustworthy and reliable sources

Beef Producers\u27 Risk Perceptions of an Agroterrorism Event Occurring in Oklahoma

The purpose of this statewide study was to determine Oklahoma beef producers’ perceptions of the susceptibility of the state’s beef industry to a terrorist attack. Participants in this study were randomly selected from a population of 48,000 beef producers in this Oklahoma. All 470 respondents completed a telephone survey conducted by the Oklahoma Agricultural Statistics Service. Descriptive statistics, t-tests, and cross tabulations were used to analyze the data. Oklahoma beef producers perceived the beef industry was susceptible to an agroterrorism event, believed the feedlots to be at an elevated level of threat, were confident in their own operation’s biosecurity measures, believed their own operation was not susceptible to an agroterrorism event, and did not believe they had enough information about protection from terrorism to the beef industry

A spatially-structured PCG method for content diversity in a Physics-based simulation game

This paper presents a spatially-structured evolutionary algorithm (EA) to procedurally generate game maps of di ferent levels of di ficulty to be solved, in Gravityvolve!, a physics-based simulation videogame that we have implemented and which is inspired by the n- body problem, a classical problem in the fi eld of physics and mathematics. The proposal consists of a steady-state EA whose population is partitioned into three groups according to the di ficulty of the generated content (hard, medium or easy) which can be easily adapted to handle the automatic creation of content of diverse nature in other games. In addition, we present three fitness functions, based on multiple criteria (i.e:, intersections, gravitational acceleration and simulations), that were used experimentally to conduct the search process for creating a database of maps with di ferent di ficulty in Gravityvolve!.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Investigating the use of an ensemble of evolutionary algorithms for letter identification in tremulous medieval handwriting

Ensemble classifiers are known for performing good generalization from simpler and less accurate classifiers. Ensembles have the ability to use the variety in classification patterns of the smaller classifiers in order to make better predictions. However, to create an ensemble it is necessary to determine how the component classifiers should be combined to generate the final predictions. One way to do this is to search different combinations of classifiers with evolutionary algorithms, which are largely employed when the objective is to find a structure that serves for some purpose. In this work, an investigation is carried about the use of ensembles obtained via evolutionary algorithm for identifying individual letters in tremulous medieval writing and to differentiate between scribes. The aim of this research is to use this process as the first step towards classifying the tremor type with more accuracy. The ensembles are obtained through evolutionary search of trees that aggregate the output of base classifiers, which are neural networks trained prior to the ensemble search. The misclassification patterns of the base classifiers are analysed in order to determine how much better an ensemble of those classifiers can be than its components. The best ensembles have their misclassification patterns compared to those of their component classifiers. The results obtained suggest interesting methods for letter (up to 96% accuracy) and user classification (up to 88% accuracy) in an offline scenario