Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 130-135).

Multicast is a bandwidth efficient mechanism to provide wireless services for a group of nodes. Providing reliable wireless multicast is challenging due to channel fading. This thesis investigates cooperation among receiving nodes to enhance the reliability of wireless multicast. A time division based cooperative multicast strategy is proposed, and the optimal scheduling scheme is found to maximize the system throughput. It is shown that the optimal relay number is bounded by a threshold, and the optimal time allocation can be found using an efficient algorithm. Numerical results show that the proposed strategy can enhance network performance when the average channel condition between receiving nodes is better than that of the direct link. To provide incentive for cooperation, this thesis further studies the interactions among selfish nodes using game theoretic approaches. The cooperative multicast process is modeled as a repeated game and the desired cooperation state which satisfies the absolute fairness and the Pareto optimality criteria is found. A Worst Behavior Tit-for-Tat incentive strategy is designed to enforce cooperation and its effectiveness is studied under both the perfect and the imperfect monitoring scenarios. To address the issue of imperfect monitoring, an interval based estimation method is proposed. Simulation results show that the proposed strategy can enforce cooperation efficiently even the monitoring is imperfect. / Signal and Image Processing

This thesis is composed of two studies: (1) an assessment of the vertical habitat use of swordfish Xiphias gladius in the Florida Straits; and (2) a systematic description of the southeast Florida recreational swordfish fishery. First, the vertical distribution of swordfish (Xiphias gladius) was assessed in relation to diel cycles and lunar phase from data gathered utilizing popup satellite archival tags (PSATs). Seven tags were deployed in the Florida Straits during this study from recreational and commercial fishing vessels; two fish died shortly after deployment, and the remaining five were included in the analysis. Tags were deployed for periods ranging from 120 to 151 days and recorded data on temperature, depth, and light level every ten seconds. Transmitted data was summarized into one hour histograms. Swordfish vertical distribution in response to diel cycles was characterized by typically spending daytime hours below 500 m and nighttime hours in waters less than 75 m. Swordfish distribution differed significantly in response to lunar phase, with animals occupying successively deeper depths in response to increasing lunar illumination. This study is consistent with the widely accepted hypothesis that the swordfish vertical distribution is a function of ambient light levels. However, in contradiction to this hypothesis was the observation of a number of daytime surfacing events recorded by the tags. This less pronounced but frequent behavior is hypothesized as a mechanism to warm the fish?s body after extended daytime feeding dives to great depths. A recreational fishery targeting swordfish in southeast Florida has gained popularity in recent years. However, little data is currently available on the fishery and its participants. A survey was distributed to recreational swordfish anglers at local swordfish fishing club meetings and a swordfish fishing tournament to describe the fishery and its participants. Questions were organized into four sections: demographics, fishing habits, cost, and views on regulations. A total of 38 surveys were completed by anglers and included in the study. Recreational swordfish fishermen in southeast Florida were mainly Caucasian, with the largest group by percentage ranging from 41-50 years of age. Most fishers surveyed had over 20 years recreational fishing experience, with less than 10 years experience targeting swordfish. Anglers typically fished out of center console boats ranging from 21-35 feet, and usually made less than 50 trips per year. Costs associated with the fishery typically exceed those associated with general recreational saltwater fisheries by thousands of dollars (USFWS, 2006). Fishers were divided in their views on the current recreational swordfish regulations. Forty percent of anglers surveyed were unsatisfied, 37% were satisfied, and 23% remained neutral.

Automated devices enabled by wireless communications are deployed for a variety of purposes. As they become more ubiquitous, their interaction becomes increasingly important for coexistence when sharing a scarce resource, and for leveraging potential cooperation to achieve larger design goals. This thesis investigates the use of game theory as a tool for design and analysis of networked systems of automated devices in the areas of naval defence, wireless environmental monitoring through sensor networks, and cognitive radio wireless communications. In the first part, decentralized operation of naval platforms deploying electronic countermeasures against missile threats is studied. The problem is formulated as a stochastic game in which platforms independently plan and execute dynamic strategies to defeat threats in two situations: where coordination is impossible due to lack of communications, and where platforms hold different objectives but can coordinate, according to the military doctrine of Network Enabled Operations. The result is a flexible, robust model for missile deflection for advanced naval groups. Next, the problem of cooperative environmental monitoring and communication in energy-constrained wireless sensor networks is considered from a game-theoretic perspective. This leads to novel protocols in which sensors cooperatively trade off performance with energy consumption with low communication and complexity overhead. Two key results are an on-line adaptive learning algorithm for tracking the correlated equilibrium set of a slowly varying sensor deployment game, and an analysis of the equilibrium properties of threshold policies in a game with noisy, correlated measurements. Finally, the problem of dynamic spectrum access for systems of cognitive radios is considered. A game theoretic formulation leads to a scheme for competitive bandwidth allocation which respects radios' individual interests while enforcing fairness between users. An on-line adaptive learning scheme is again proposed for negotiating fair, equilibrium resource allocations, while dynamically adjusting to changing conditions.

Through looking into the inner workings of stealth centric games, this paper aims to find out the essential components of this type of videogames. Examining the history of such games and the design principles of stealth centric games in relation to the participating player this paper will methodically examine games in the light of the arguments of industry professionals. After that a framework is extracted, identifying the principal core components of stealth centric game design.

Corruption is an important social and ethical problem / fight with it requires changes in values, norms and behavioral patterns of the society. This is usually a long and difficult process. Decades should pass to change deep values of a society. In the mean time, it is possible to combat corruption by changing incentive structures in the economy. If deep causes of the problem are analyzed carefully, a new system of governance can be established, such that, even most opportunist individuals do not find getting involved in corrupt practices profitable. Aim of this thesis is to examine characteristics of the system providing a fertile environment for corruption and to figure out factors stimulating corrupt transactions using game theoretical models. The first two models examine corruption as a kind of transaction between the briber and the bribee. In the models, it is shown that intermediaries sector occur from the profit maximization behavior of agents. This sector, by establishing long term, trust based relationships with bureaucrats, decreases risks occurring from the fact that the two parties involved in a corrupt transaction do not know each other perfectly. This sector, by reducing the likelihood of detection, serves corrupt transactions, and in return for the service it provided, takes commission, so gets benefit. Third model examines a strange type of corruption, a case of (spurious) middlemen obtaining bribe from the public service bureaucrats give, by pretending that he has influence on the acceptance or speed of it. The model tries to detect the characteristics of the environment making such a deception process persistent.

We study the connectivity properties of the Internet graph and its impact on its structure.

This study examines the players experience, environments and objects in the videogame World of Warcraft. The purpose of this study is to get more knowledge about the players experience in the game with the focus on factors contributing to some form of immersion or/and presence. The data for this study were gathered using interviews as method and then analyzed with relevant literature in the chosen field. A game content analysis and a group of questions are tested with the results of the study which is presented at the end in with an analytic discussion.

The purpose of this project was to provide a deeper understanding of web services, particularlyin the context of an online multi-player game. This paper describes the designand implementation of certain features of the action game Superfighters Deluxe. Thesefeatures include a dynamic website, a user account system, a multi-player game serverbrowser and a system for automatic software updates. This thesis reviews strengths andweaknesses of web technologies such as ASP.NET and PHP and database technologiessuch as MySQL and SQL Server. The technologies used in this project were ASP.NETand MySQL. We determined that these technologies are powerful, reliable and flexibletools for creating web applications. The conclusions of this research are supported by theresults of internal and public testing of the applications. / Syftet med det här projektet var att ge en djupare förståelse för web services, speciellt isamband med ett online-multi-playerspel. Rapporten beskriver designen och implementationenav vissa beståndsdelar av actionspelet Superfighters Deluxe. Bland dessa featuresfinns en dynamisk webbplats, ett användarkontosystem, en game server browser för onlinespelsamt ett system för automatiska mjukvaruuppdateringar. Den här rapporten undersökerstarka och svaga sidor hos webbteknologier såsom ASP.NET och PHP och databasteknologiersåsom MySQL och SQL Server. Teknologierna som användes i projektetvar ASP.NET och MySQL. Vi konstaterade att dessa teknologier är kraftfulla, pålitligaoch flexibla verktyg för att skapa webbapplikationer. Slutsatserna av vår forskningstöds av resultaten från interna och publika tester av de olika applikationerna.

The purpose of this project is to test and improve people’s ability of face recognition. Although there are some tests on the internet with the same purpose, the problem is that people may feel bored and give up before finishing the tests. Consequently they may not benefit from testing nor from training. To solve this problem, face recognition and online game are put together in this project. The game is supposed to provide entertainment when people are playing, so that more people can take the test and improve their abilities of face recognition. In the game design, the game is assumed to take place in the face recognition lab, which is an imaginary lab. The player plays the main role in this game and asked to solve a number of problems. There are several scenarios waiting for the player, which mainly need face recognition skills from the player. At the end the player obtains the result of evaluation of her/his skills in face recognition.