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Heuristic algorithms for motion planningEldershaw, Craig January 2001 (has links)
Motion planning is an increasingly important field of research. Factory automation is becoming more prevalent and at the same time, production runs are shortening in the name of customisation. With computer controlled equipment becoming cheaper and more modular, setting up near-fully automated production lines is becoming fast and easy. This means that the actual programming of the robots and assembly system is becoming the rate determining step. Automated motion planning is a possible solution to this—but only if it can run fast enough. Many heuristic planners have been created in an attempt to achieve the necessary speeds in off-line (or more ambitiously, on-line) processing. This thesis aims to show that different types of heuristic planners can be designed to take advantage of specialised environments or robot characteristics. To show this, three distinct classes of heuristic planners are put forward for discussion. The first of these classes, addressed in Chapter 2, is of very generic planners which will work in virtually all situations (ie. almost any combination of robot and environment). This generality is obviously useful when lacking more specific domain knowledge. However these methods do suffer performance-wise in comparison with more specialised planners when there are characteristics of the problem which can be targeted. Chapter 3 moves to planners which are designed to specifically address certain peculiarities of the environment. Particular focus is given to environments whose corresponding configuration-spaces contain narrow gaps and passages. Finally Chapter 4 addresses a third class of planners: those which are designed for specific types of robots and movements. The particular focus is on locomotion for legged vehicles. For each of these three classes, some discussion is made of existing planners which can be so characterised. In addition, a novel algorithm is introduced in each as an example for particular consideration.
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Comparison between Optimization and Heuristic Methods for Large-Scale Infrastructure Rehabilitation ProgramsBinhomaid, Omar January 2012 (has links)
Civil infrastructure systems are the foundation of economic growth and prosperity in all nations. In recent years, infrastructure rehabilitation has been a focus of attention in North America and around the world. A large percentage of existing infrastructure assets is deteriorating due to harsh environmental conditions, insufficient capacity, and age. Ideally, an assets management system would include functions such as condition assessment, deterioration modeling, repair modeling, life-cycle cost analysis, and asset prioritization for repair along a planning horizon. While many asset management systems have been introduced in the literature, few or no studies have reported on the performance of either optimization or heuristic tools on large-scale networks of assets.
This research presents an extensive comparison between heuristic and genetic-algorithm optimization methods for handling large-scale rehabilitation programs. Heuristic and optimization fund-allocation approaches have been developed for three case studies obtained from the literature related to buildings, pavements, and bridges with different life cycle cost analysis (LCCA) formulations. Large-scale networks were constructed for comparing the efficiency of heuristic and optimization approaches on large-scale rehabilitation programs. Based on extensive experiments with various case studies on different network sizes, the heuristic technique proved its practicality for handling various network sizes while maintaining the same efficiency and performance levels. The performance of the genetic algorithm optimization approach decreased with network size and model complexity. The optimization technique can provide a high performance level, given enough processing time.
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Structure and inference in classical planningLipovetzky, Nir 07 December 2012 (has links)
Classical planning is the problem of finding a sequence of actions for
achieving a goal from an initial state assuming that actions have
deterministic effects. The most effective approach for finding such
plans is based on heuristic search guided by heuristics extracted
automatically from the problem representation. In this thesis, we
introduce alternative approaches for performing inference over the
structure of planning problems that do not appeal to heuristic
functions, nor to reductions to other formalisms such as SAT or
CSP. We show that many of the standard benchmark domains can be solved
with almost no search or a polynomially bounded amount of search, once
the structure of planning problems is taken into account. In certain
cases we can characterize this structure in terms of a novel width
parameter for classical planning. / Los problemas en planificación clásica consisten en encontrar la
secuencia de acciones que lleve a un agente a su objetivo desde un
estado inicial, asumiendo que los efectos de las acciones son
determinísticos. El enfoque más efectivo para encontrar dichos
planes es la búsqueda heurística, extrayendo de la
representación del problema de forma automática heurísticas que
guien la búsqueda. En esta tesis, introducimos enfoques
alternativos para realizar inferencias sobre la estructura del los
problemas de planificación, sin apelar a funciones heurísticas,
reducciones a SAT o CSP. Demostramos que la mayoría de
problemas estándares pueden ser resueltos casi sin búsqueda o con
una cantidad de búsqueda polinomialmente limitada, en algunos casos,
caracterizando la estructura de los problemas en término de un nuevo
parámetro de complejidad para la planificación clásica.
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Vastra Avatar: a personal manifestation of fashion, culture, and identityNaware, Mihika January 2009 (has links)
This research project asks; what is the potential for garments to express an Indian/European cultural hybridisation? The research explores the development of an alternative aesthetic by hybridising the ethos of traditional Indian garments and the aesthetics of 'Western' garments. The garments have been designed and constructed after key design features were indentified, and the new garments reflect hybridisation. The aspect of hybridisation was further enhanced with the use of digitally-printed fabric imagery which features a mythologised and idealised European/Indian history. The research seeks to discover if such a joining-together could develop an aesthetic sensibility, informed by both a ‘Western’ enculturation and a traditional Indian heritage. The new garments will speak to the viewer about what it is to experience being situated within two cultures simultaneously.
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On the performance of optimisation networks / by Brenton S. Cooper.Cooper, Brenton S. January 1996 (has links)
Bibliography: leaves 125-131. / xi, 131 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis examines the performace of optimisation networks. The main objectives are to determine if there exist any factors which limit the solution quality that may be achieved with optimisation networks, to determine the reasons for any such limitations and to suggest remedies for them. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996
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Effectively capturing user sessions on the Web using Web server logsCaldera, Amithalal, University of Western Sydney, College of Science, Technology and Environment, School of Computing and Information Technology January 2005 (has links)
The usage of Web sites has been of interest to Web administrators and researchers ever since the Web started. Analysis of Web site usage data helps to understand the behaviour of its users, which is very important, as many important decisions can be made based on it. The user behaviour may be deduced by knowing all the activities each user does from the time s/he starts a session on the Web site until s/he leaves it, which is collectively called a user session. As Web server logs explicitly record the browsing behaviour of site users and are readily and economically available, this thesis explores the use of Web server logs in capturing user sessions on Web. In order to protect users’ privacy, the standard Web server logs in general do not record the user identities or similar measures to uniquely identify the users. This thesis concentrates on heuristic strategies to infer user sessions. The heuristics exploit the background knowledge of user navigational behaviour recorded in the standard Web server logs without requiring additional information through cookies, logins and session ids. They identify relationships that may exist among the log data and make use of them to assess whether requests registered by the Web server can belong to the same individual and whether these requests were performed during the same visit. Researchers have proposed several heuristics, which were adversely affected by proxy servers, caching and undefined referrers. The thesis proposes new heuristics, which effectively address all the limitations, thus extending the work in this field. It also introduces a set of measures to quantify the performance of the heuristics and uses them to investigate their efficiency based on logs from three Web sites and makes recommendations for the Web sites to devise their own heuristics. The investigation has shown satisfactory results and the new heuristics are applicable to wider range of Web sites. / Doctor of Philosophy (PhD)
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A visual interpretation of Chinese immigrants’ identity dilemma in New ZealandZhang, Nuo January 2008 (has links)
This thesis explores the notion of identity dilemma and its visualisation in the context of New Zealand Chinese immigration. It focuses on interpreting and visualising New Zealand Chinese immigrants’ thoughts and feelings and their struggle to adapt to the environment as well as their ambivalent negotiation to balance their in-between identity of being a New Zealander (Westerner) and Chinese. It is a practice-based project and is presented by means of photography, with illustration as the supporting medium. The predicament of identity is explored through interviewing members of the New Zealand Chinese community. A semi-constructed interview is designed and introduced to canvass 20 Chinese participants’ opinions of their cultural beliefs and sense of belonging in a Western society. The data is collected and analysed to investigate the informants’ thoughts and feelings in their daily routine in a multicultural community. I, as an art and design practitioner, visually interpret and transcend my opinion of identity dilemma of Chinese immigrants into my practical works. The participants’ thoughts and feelings are transferred into my artwork through creating patterns of visual elements. Employing a heuristic visual research method, my explorative work attempts to transfer social research findings of the idea of identity dilemma into my artwork for initiating contemporary visual discourse.
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Vastra Avatar: a personal manifestation of fashion, culture, and identityNaware, Mihika January 2009 (has links)
This research project asks; what is the potential for garments to express an Indian/European cultural hybridisation? The research explores the development of an alternative aesthetic by hybridising the ethos of traditional Indian garments and the aesthetics of 'Western' garments. The garments have been designed and constructed after key design features were indentified, and the new garments reflect hybridisation. The aspect of hybridisation was further enhanced with the use of digitally-printed fabric imagery which features a mythologised and idealised European/Indian history. The research seeks to discover if such a joining-together could develop an aesthetic sensibility, informed by both a ‘Western’ enculturation and a traditional Indian heritage. The new garments will speak to the viewer about what it is to experience being situated within two cultures simultaneously.
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Using a Contingent Heuristic Approach and Eye Gaze Tracking for the Usability Evaluation of Web Sitespilunp@gmail.com, Pilun Piyasirivej January 2005 (has links)
This thesis describes a research study in the field of Human-Computer Interaction (HCI), specifically usability evaluation. The research investigated ways to optimise the usability of Web sites. It specifically compared Flash and HTML versions of several different types of Web sites. The study commenced with a literature review regarding the process of usability evaluation of Web sites. Various usability evaluation methods and techniques were explored, and two emerging techniques were chosen for further investigation: (1) a contingent heuristic approach; and (2) eye gaze tracking. In order to confirm that these two techniques can be used effectively for Web site usability evaluations, two experiments were conducted to evaluate the usability of Web sites. The first experiment utilised an online questionnaire derived from the Website Usability Contingent Evaluation Tool (WUCET), which was based on the contingent heuristic approach. The second experiment involved eye gaze tracking with the faceLAB system, while participants interacted with Web sites of different types. Both experiments utilised Flash and HTML versions of the same set of Web sites. By analysing data collected from the experiments, comparisons between the usability of Flash and HTML versions were made. The results from quantitative and qualitative analyses of survey responses suggested that Flash version of Web sites, in general, provided higher usability than HTML version of Web sites, but eye gaze tracking data analyses showed no significant difference between the two versions. However, analyses of the eye tracking data were useful for improving understanding of the ways in which users interact with different versions of the Web sites. In addition, other influential factors that could affect the perceived usability of the Web sites, such as users gender and previous experience with computers and the Web, were also considered. The results of the experiments showed that in regard to Flash and HTML implementations of Web sites, there was a difference in Web site usability perception patterns between male and female users, and also between users with long-term computer/Web experience and users with short-term experience. In addition, a range of different types (purposes) of Web sites were utilised. In this study, selected Web sites fall into three broad categories according to their main purpose: (1) information; (2) entertainment; and (3) e-commerce. It was discovered that the type of Web sites also influenced the usability of Flash and HTML versions of Web sites, as perceived by users.
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Designing multimodal public transport networks using metaheuristicsFletterman, Manuel. January 2008 (has links)
Thesis (M.Sc.(Industrial engineering))--University of Pretoria, 2008. / Includes bibliographical references (leaves 82-84).
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