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This thesis studies the importance and implications of information asymmetry in decentralized markets with search frictions. The first chapter provides an introduction and literature review. In the next chapter, I propose a model of the housing market using a search framework in which sellers are unable to commit to asking prices announced ex ante. Relaxing the commitment assumption prevents sellers from using price posting as a signalling device to direct buyers' search. Adverse selection and inefficient entry on the demand side then contribute to housing market illiquidity. Real estate agents that can facilitate the search process can segment the market and alleviate information frictions. In Chapter 3, I further study the importance and implications of the commitment assumptions embedded in directed search models. I eliminate commitment to take-it-or-leave-it trading mechanisms in a model of the labour market with worker heterogeneity and a matching process that allows for multiple firms to match with a single worker. When workers and firms cannot commit to ex ante offers, to an allocation rule, or to an ex post bargaining strategy, the equilibrium is necessarily inefficient. This is true for a broad class of protocols for wage determination, of which bilateral bargaining and Bertrand competition are special cases. Finally, Chapter 4 presents a theory of land market activity for settings where there is uncertainty and private information about the security of land tenure. Land sellers match with buyers in a competitive search environment, and an illiquid land market emerges as a screening mechanism. The implications of the theory are tested using household level data from Indonesia. As predicted, formally titled land is more liquid than untitled land in the sense that ownership rights are more readily transferable. / Thesis (Ph.D, Economics) -- Queen's University, 2012-10-09 22:03:23.045

Three experiments were conducted to investigate the hypothesis that young infants? failures to search for occluded objects arises, not from deficiencies in their object representations, but from limitations in experience with the physical world. Successful means-end search is typically found at 8 months of age and is traditionally taken as the hallmark of object permanence. However, recent evidence suggests that infants much younger than 8 months of age are able to represent and reason about objects that are no longer visible. In Experiment 1, successful means-end search was found for 8. 5-, but not 6. 5-month-old infants in a traditional task, but younger infants showed successful search ability when the task was made familiar to them in Experiment 2 (i. e. , when the toy and occluder are first presented as a single composite object), and when they were given the opportunity to watch a demonstration of the solution to the task in Experiment 3. These results are taken as evidence for the ?experiential limitation? hypothesis and suggest that young infants are more apt at solving manual search tasks than previously acknowledged.

This thesis presents four largely independent essays on industrial organisation. The first three essays examine how search and switching costs distort competitive markets, whilst the fourth essay studies how firms themselves might eliminate competition by agreeing to fix the market price. The key insight from the first two essays is that by choosing to pay a search cost, a consumer reveals to a retailer some private information about their product valuations. In this context the first essay re-examines the well-known theoretical Diamond Paradox in which markets completely break down if firms sell only a single product. I demonstrate that multiproduct retailers offer an elegant and realistic way of overcoming this Paradox, and then apply the model to supermarkets. In particular, this essay provides new insights into why convenience stores charge high prices and why grocery stores use selected loss-leaders. The second essay looks at internet search and therefore focuses on the special case in which search frictions become very small. It seeks to explain why retailers pay so much for online advertising, when consumers can easily click on whichever links they like. I show that if consumers have prior information about products, their search behaviour is limited but very informative about their preferences. This places prominent firms in a privileged position, and makes them substantially more profitable. The third essay provides a simple model in which small switching costs are pro-competitive and beneficial to consumers. This challenges the conventional wisdom, but also argues that switching costs should be less of a policy priority than search costs. The final essay examines a game in which two firms bargain over a collusive price. It is shown that entry into such a market may make collusion easier, and may increase price.

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This thesis builds a foundation for the philosophy of theWeb by examining the crucial question: What does a Uniform Resource Identifier (URI) mean? Does it have a sense, and can it refer to things? A philosophical and historical introduction to the Web explains the primary purpose of theWeb as a universal information space for naming and accessing information via URIs. A terminology, based on distinctions in philosophy, is employed to define precisely what is meant by information, language, representation, and reference. These terms are then employed to create a foundational ontology and principles ofWeb architecture. From this perspective, the SemanticWeb is then viewed as the application of the principles of Web architecture to knowledge representation. However, the classical philosophical problems of sense and reference that have been the source of debate within the philosophy of language return. Three main positions are inspected: the logicist position, as exemplified by the descriptivist theory of reference and the first-generation SemanticWeb, the direct reference position, as exemplified by Putnamand Kripke’s causal theory of reference and the second-generation Linked Data initiative, and a Wittgensteinian position that views the Semantic Web as yet another public language. After identifying the public language position as the most promising, a solution of using people’s everyday use of search engines as relevance feedback is proposed as a Wittgensteinian way to determine sense of URIs. This solution is then evaluated on a sample of the Semantic Web discovered by via using queries from a hypertext search engine query log. The results are evaluated and the technique of using relevance feedback from hypertext Web searches to determine relevant Semantic Web URIs in response to user queries is shown to considerably improve baseline performance. Future work for the Web that follows from our argument and experiments is detailed, and outlines of a future philosophy of the Web laid out.

This thesis evaluates novel electronic physiologic monitor potential in remote and rural search and rescue. Casualties are often located a considerable distance away from definitive care. Their rescue involves a variety of groups, including volunteer rescue teams. Rescuers manage a wide range of medical problems, from minor issues to more serious, life-threatening conditions. However, casualty monitoring is restricted by steep terrain and extreme environmental conditions. Evidence indicated that novel electronic physiologic monitors were in development. Some were lightweight and wireless – it was hypothesised that such technology could facilitate health monitoring, conferring benefits to casualties and their carers. Novel physiologic monitor potential was explored using a multi-method approach, involving four methodologically distinct pieces of research. This included a reverseengineering approach to define the rescue context. A thematic review of remote and rural casualty rescues identified a potential worldwide demand for a novel monitor, although only a small proportion of casualties had severe injury. A longitudinal analysis of UK remote and rural casualties confirmed a consistent mountain rescue casualty demand for monitoring. Injury was more frequent than illness and a majority of injury involved suspected fracture to the lower extremity. A qualitative study identified evidence of support for novel monitors amongst rescuer groups. However, some felt that the environment and the variety of rescuer first-aid and medical training could negate monitor potential. A laboratory-function study evaluated the performance of an example of a novel monitor under simulated rescue conditions. There was little effect of several layers of clothing and a mountain rescue casualty bag on data accuracy. Taking all the evidence gathered into consideration, it was concluded that novel electronic physiologic monitors did have potential in remote and rural search and rescue. A concept design for a rescue-specific physiologic monitor was proposed, including software, hardware and architecture for future use.

As recommender systems have increasingly become prevalent to guide consumers to find their desired products in many industries, understanding the impact of recommender systems on consumer choices is critical to the business performance and raises important policy implications. In this thesis, we examine the role of different recommendation schemes, spanning from interpersonal recommendations in social environment given by peers to product display recommendations in physical shopping environment given by sellers on consumers’ switching and search behavior in two distinct case studies. In the first study, we look at the effect of peer recommendations on subscriber churn in a large mobile network. We find that consumers’ propensity to churn increases with the number of friends that churn and in particular with the number of strong friends that churn. In the second study, we implement an in-vivo randomized field experiment to measure the effect of product display recommendations as book placement on shopper behavior in a physical bookstore. We leverage video tracking technologies to monitor how shoppers respond to random book placement, which induces random search costs. We find that books recommended at the edge of the table are more likely to be picked and taken than those placed at the center of the table. More interestingly, we also find that conditional on being picked, shoppers are equally likely to take books placed at the edge and at the center of the table, suggesting that display recommendations positively affect consumer choice mainly through its effect on the search process and not through its effect on the consideration process. Therefore, we empirically show that provision of recommendations, although in different schemes, may generally help to reduce consumers’ search costs in product or service discovery process, relative to what they would do without such an intervention. Moreover, we perform a comparative analysis between offline and online applications of recommender systems to systematically investigate the current practices, future prospects and policy perspectives when applying recommender systems in physical retailing. All these issues highlight opportunities for physical retailers to design, implement and evaluate their recommender systems that offer convenience benefits and appropriate protection to consumers.

In this thesis the problem of conceptual engineering design and the possible use of adaptive search techniques and other machine based methods therein are explored. For the multi-objective optimisation (MOO) within conceptual design problem, genetic algorithms (GA) adapted to MOO are used and various techniques explored: weighted sums, lexicographic order, Pareto method with and without ranking, VEGA-like approaches etc. Large number of runs are performed for findingZ Dth e optimal configuration and setting of the GA parameters. A novel method, weighted Pareto method is introduced and applied to a real-world optimisation problem. Decision support methods within conceptual engineering design framework are discussed and a new preference method developed. The preference method for translating vague qualitative categories (such as "more important 91 , 4m.9u ch less important' 'etc. ) into quantitative values (numbers) is based on fuzzy preferences and graph theory methods. Several applications of preferences are presented and discussed: * in weighted sum based optimisation methods; s in weighted Pareto method; * for ordering and manipulating constraints and scenarios; e for a co-evolutionary, distributive GA-based MOO method; The issue of complexity and sensitivity is addressed as well as potential generalisations of presented preference methods. Interactive dynamical constraints in the form of design scenarios are introduced. These are based on a propositional logic and a fairly rich mathematical language. They can be added, deleted and modified on-line during the design session without need for recompiling the code. The use of machine-based agents in conceptual design process is investigated. They are classified into several different categories (e. g. interface agents, search agents, information agents). Several different categories of agents performing various specialised task are developed (mostly dealing with preferences, but also some filtering ones). They are integrated with the conceptual engineering design system to form a closed loop system that includes both computer and designer. All thesed ifferent aspectso f conceptuale ngineeringd esigna re applied within Plymouth Engineering Design Centre / British Aerospace conceptual airframe design project.