58 research outputs found

    Semantic description and matching of services for pervasive environments

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    With the evolution of the World Wide Web and the advancement of the electronic world, the diversity of available services is increasing rapidly.This raises new demands for the efficient discovery and location of heterogeneous services and resources in dynamically changing environments. The traditional approaches for service discovery such as UDDI, Salutation, SLP etc. characterise the services by using predefined service categories and fixed attribute value pairs and the matching techniques in these approaches are limited to syntactic comparisons based on attributes or interfaces. More recently with the popularity of Semantic Web technologies, there has been an increased interest in the application of reasoning mechanisms to support discovery and matching. These approaches provide important directions in overcoming the limitations present in the traditional approaches to service discovery. However, these still have limitations and have overlooked issues that need to be addressed; particularly these approaches do not have an effective ranking criterion to facilitate the ordering of the potential matches, according to their suitability to satisfy the request under concern. This thesis presents a semantic matching framework to facilitate effective discovery of device based services in pervasive environments. This offers a ranking mechanism that will order the available services in the order of their suitability and also considers priorities placed on individual requirements in a request during the matching process. The proposed approach has been implemented in a pervasive scenario for matching device-based services. The Device Ontology which has been developed as part of this research, has been used to describe the devices and their services. The retrieval effectiveness of this semantic matching approach has been formally investigated through the use of human participant studies and the experimental results have indicated that the results correlate well with human perception. The performance of the solution has also been evaluated, to explore the effects of employing reasoning mechanisms on the efficiency of the matching process. Specifically the scalability of the solution has been investigated with respect to the request size and the number of advertisements involved in matching.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Agent-based resource management for grid computing

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    A computational grid is a hardware and software infrastructure that provides dependable, consistent, pervasive, and inexpensive access to high-end computational capability. An ideal grid environment should provide access to the available resources in a seamless manner. Resource management is an important infrastructural component of a grid computing environment. The overall aim of resource management is to efficiently schedule applications that need to utilise the available resources in the grid environment. Such goals within the high performance community will rely on accurate performance prediction capabilities. An existing toolkit, known as PACE (Performance Analysis and Characterisation Environment), is used to provide quantitative data concerning the performance of sophisticated applications running on high performance resources. In this thesis an ASCI (Accelerated Strategic Computing Initiative) kernel application, Sweep3D, is used to illustrate the PACE performance prediction capabilities. The validation results show that a reasonable accuracy can be obtained, cross-platform comparisons can be easily undertaken, and the process benefits from a rapid evaluation time. While extremely well-suited for managing a locally distributed multi-computer, the PACE functions do not map well onto a wide-area environment, where heterogeneity, multiple administrative domains, and communication irregularities dramatically complicate the job of resource management. Scalability and adaptability are two key challenges that must be addressed. In this thesis, an A4 (Agile Architecture and Autonomous Agents) methodology is introduced for the development of large-scale distributed software systems with highly dynamic behaviours. An agent is considered to be both a service provider and a service requestor. Agents are organised into a hierarchy with service advertisement and discovery capabilities. There are four main performance metrics for an A4 system: service discovery speed, agent system efficiency, workload balancing, and discovery success rate. Coupling the A4 methodology with PACE functions, results in an Agent-based Resource Management System (ARMS), which is implemented for grid computing. The PACE functions supply accurate performance information (e. g. execution time) as input to a local resource scheduler on the fly. At a meta-level, agents advertise their service information and cooperate with each other to discover available resources for grid-enabled applications. A Performance Monitor and Advisor (PMA) is also developed in ARMS to optimise the performance of the agent behaviours. The PMA is capable of performance modelling and simulation about the agents in ARMS and can be used to improve overall system performance. The PMA can monitor agent behaviours in ARMS and reconfigure them with optimised strategies, which include the use of ACTs (Agent Capability Tables), limited service lifetime, limited scope for service advertisement and discovery, agent mobility and service distribution, etc. The main contribution of this work is that it provides a methodology and prototype implementation of a grid Resource Management System (RMS). The system includes a number of original features that cannot be found in existing research solutions

    Methods for Efficient and Accurate Discovery of Services

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    With an increasing number of services developed and offered in an enterprise setting or the Web, users can hardly verify their requirements manually in order to find appropriate services. In this thesis, we develop a method to discover semantically described services. We exploit comprehensive service and request descriptions such that a wide variety of use cases can be supported. In our discovery method, we compute the matchmaking decision by employing an efficient model checking technique

    Artificial intelligence based decision support for trumpeter swan management

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    Department Head: Susan G. Stafford.2002 Spring.Includes bibliographical references (pages 108-114).The number of trumpeter swans (Cygnus buccinator) breeding in the Tri-State area where Montana, Idaho, and Wyoming come together has declined to just a few hundred pairs. However, these birds are part of the Rocky Mountain Population which additionally has over 3,500 birds breeding in Alberta, British Columbia, Northwest Territories, and Yukon Territory. To a large degree, these birds seem to have abandoned traditional migratory pathways in the flyway. Waterfowl managers have been interested in decision support tools that would help them explore simulated management scenarios in their quest towards reaching population recovery and the reestablishment of traditional migratory pathways. I have developed a decision support system to assist biologists with such management, especially related to wetland ecology. Decision support systems use a combination of models, analytical techniques, and information retrieval to help develop and evaluate appropriate alternatives. Swan management is a domain that is ecologically complex, and this complexity is compounded by spatial and temporal issues. The Distributed Environment Centered Agent Framework (DECAF) was successful at integrating communications among agents, integrating ecological knowledge, and simulating swan distributions through implementation of a queuing system. The work I have conducted indicates a need for determining what other factors might allow a deeper understanding of the effects of management actions on the flyway distribution of waterfowl. Knowing those would allow the more refined development of algorithms for effective decision support systems via collaboration by intelligent agents. Additional, specific conclusions and ideas for future research related both to waterfowl ecology and to the use of multiagent systems have been triggered by the validation work

    Serving Two Masters : A Study of Quantitative Literacy at Small Colleges and Universities

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    The past twenty years have seen a growing interest in promoting quantitative literacy (QL) courses at the college level. At small institutions, financial realities impose limitations on faculty size and therefore the variety of courses that may be offered. This study examined course offerings below calculus at four hundred twenty-eight small colleges to gain a thorough understanding of the approaches to developing QL among the general population of undergraduate students. Using a three-phase model of examining progressively narrower subsets of QL programs at small institutions, document-based data from college catalogs and communication with mathematics program chairs were studied to summarize the most common approaches to QL, and to provide narrative descriptions of courses and programs most consistent with the recommendations of the Mathematical Association of America. The analysis of the data includes information on actual curricula and enrollments, and uses qualitative techniques to provide descriptions of successful courses and programs. Through this analysis, variables important in developing effective QL courses and programs at the undergraduate level were identified. The support of both the mathematics department and an institution’s administration were determined to be necessary factors in successful QL programs. Other factors contributing to program or course success were the individual efforts of faculty members in teaching QL courses, and the development of print-based materials conducive to effective QL instruction. Finally, the study provides recommendations for developing resources to support instruction and suggests future research to promote the development of the growing body of knowledge surrounding efforts to teach quantitative reasoning within the general education curriculum

    Data‐bility: Endogamous social intimacies on dating apps in Mumbai

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    In this paper I argue through the double entendre of ‘data‐bility’ that how dateable one is on a dating app relies on data. This techno‐social framework enables an understanding of how dating apps are reconfiguring a politics of sexuality, circumscribed by digital technologies and data. Drawing on research with middle‐class women and gender‐minority dating app users in Mumbai and one dating app executive, the paper investigates how algorithms and users' digital behaviour together constitute data‐bility in three ways. First, dating app algorithms are designed to match those of similar social identities to one another. Second, dating app users engage with others' digital data on profiles and through message chats, reading class through these processes, deciding who to match/reject and correspondingly who is data‐ble. Third, users and algorithmic infrastructures come together to create new regimes of verification, through deeming some users ‘real’ and others ‘fake’ on dating apps, extending violent legacies of categorisation. Together, these processes result in data‐bility, a techno‐social order of digital dating oriented around the exclusion of those labelled ‘creeps’ along class and caste lines

    On Modularity In Abstract State Machines

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    In the field of model based formal methods we investigate the Abstract State Machine (ASM) modularity features. With the growing complexity of systems and the experience gained in more than thirty years of ASM method application a need for more manageable models emerged. We mainly investigate the notion of modules in ASMs as independent interacting components and the ability to identify portions of the machine state with the aim of improving the modelling process. In this thesis we provide a language level semantically well defined solution for (1) the definition of ASM modules as independent services and their communication behaviour; (2) a new construct that operates on the global state of an ASM machine that ease the management of state partitions and their identification; (3) a novel transition rule for the management of computations providing different execution strategies and putting termination condition for the machine inside the specification; (4) a data definition convention along with a new transition rule for their manipulation via pattern matching. In our work we build upon CoreASM, a well-known extensible modelling framework and tool environment for ASMs. The semantic of our modularity constructs is compatible with the one defined for the CoreASM interpreter. This ease the implementation of extension plugins for tool support of modularity features. A real world system use case ground model ends the thesis exemplifying the practical usage of our modularity constructs

    Multi-Agent Systems

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    This Special Issue ""Multi-Agent Systems"" gathers original research articles reporting results on the steadily growing area of agent-oriented computing and multi-agent systems technologies. After more than 20 years of academic research on multi-agent systems (MASs), in fact, agent-oriented models and technologies have been promoted as the most suitable candidates for the design and development of distributed and intelligent applications in complex and dynamic environments. With respect to both their quality and range, the papers in this Special Issue already represent a meaningful sample of the most recent advancements in the field of agent-oriented models and technologies. In particular, the 17 contributions cover agent-based modeling and simulation, situated multi-agent systems, socio-technical multi-agent systems, and semantic technologies applied to multi-agent systems. In fact, it is surprising to witness how such a limited portion of MAS research already highlights the most relevant usage of agent-based models and technologies, as well as their most appreciated characteristics. We are thus confident that the readers of Applied Sciences will be able to appreciate the growing role that MASs will play in the design and development of the next generation of complex intelligent systems. This Special Issue has been converted into a yearly series, for which a new call for papers is already available at the Applied Sciences journal’s website: https://www.mdpi.com/journal/applsci/special_issues/Multi-Agent_Systems_2019
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