Application of multi-agents to power distribution systems

The electric power system has become a very complicated network at present because of re-structuring and the penetration of distributed energy resources. In addition, due to increasing demand for power, issues such as transmission congestion have made the power system stressed. A single fault can lead to massive cascading effects, affecting the power supply and power quality. An overall solution for these issues can be obtained by a new artificial intelligent mechanism called the multi-agent system. A multi-agent system is a collection of agents, which senses the environmental changes and acts diligently on the environment in order to achieve its objectives. Due to the increasing speed and decreasing cost in communication and computation of complex matrices, multi-agent system promise to be a viable solution for today\u27s intrinsic network problems.;A multi-agent system model for fault detection and reconfiguration is presented in this thesis. These models are developed based on graph theory and mathematical programming. A mathematical model is developed to specify the objective function and the constraints.;The multi-agent models are simulated in Java Agent Development Framework and MatlabRTM and are applied to the power system model designed in the commercial software, Distributed Engineering Workstation(c) . The circuit that is used to model the power distribution system is the Circuit of the Future, developed by Southern California Edison.;The multi-agent system model can precisely detect the fault location and according to the type of fault, it reconfigures the system to supply as much load as possible by satisfying the power balance and line capacity constraints. The model is also capable of handling the assignment of load priorities.;All possible fault cases were tested and a few critical test scenarios are presented in this thesis. The results obtained were promising and were as expected

Tool flow management in batch manufacturing systems for cylindrical components

The objective of the research is to study the design of and operating strategies for advanced tool flow systems in highly automated turning systems. A prototype workstation has been built to aid this process. The thesis consists of three main parts. In the first part the current flexible manufacturing technology is reviewed with emphasis laid on tool flow and production scheduling problems. The 'State-of-the-Art' turning systems are studied, to highlight the requirement of the computer modelling of tool flow systems. In the second part, the design of a computer model using fast modelling algorithms is reported. The model design has concentrated on the tool flow system performance forecasting and improving. Attention has been given to the full representation of highly automatic features evident in turning systems. A number of contemporary production scheduling rules have been incorporated into the computer model structure, with the objectives of providing a frontend to the tool flow model, and to examine the tool flow problems interactively with the production scheduling rules. The user-interface of the model employs conversational type screens for tool flow network specification and data handling, which enhances its user friendliness greatly. An effective, fast, and easy to handle data base management system for tool, part, machine data entries has been· built up to facilitate the model performance. The third part of the thesis is concerned with the validation and application of the model with industry supplied data to examine system performance, and to evaluate alternative strategies. Conclusions drawn from this research and the recommendations for further work are finally indicated

Indoor Localization Based on Wireless Sensor Networks

Indoor localization techniques based on wireless sensor networks (WSNs) have been increasingly used in various applications such as factory automation, intelligent building, facility management, security, and health care. However, existing localization techniques cannot meet the accuracy requirement of many applications. Meanwhile, some localization algorithms are affected by environmental conditions and cannot be directly used in an indoor environment. Cost is another limitation of the existing localization algorithms. This thesis is to address those issues of indoor localization through a new Sensing Displacement (SD) approach. It consists of four major parts: platform design, SD algorithm development, SD algorithm improvement, and evaluation. Platform design includes hardware design and software design. Hardware design is the foundation for the system, which consists of the motion sensors embedded on mobile nodes and WSN design. Motion sensors are used to collect motion information for the localizing objects. A WSN is designed according to the characteristics of an indoor scenario. A Cloud Computing based system architecture is developed to support the software design of the proposed system. In order to address the special issues in an indoor environment, a new Sensing Displacement algorithm is developed, which estimates displacement of a node based on the motion information from the sensors embedded on the node. The sensor assembly consists of acceleration sensors and gyroscope sensors, separately sensing the acceleration and angular velocity of the localizing object. The first SD algorithm is designed in a way to be used in a 2-D localization demo to validate the proposal. A detailed analysis of the results of 2-D SD algorithm reveals that there are two critical issues (sensor’s noise and cumulative error) affecting the measurement results. Therefore a low-pass filter and a modified Kalman filter are introduced to solve the issue of sensor’s noises. An inertia tensor factor is introduced to address the cumulative error in a 3-D SD algorithm. Finally, the proposed SD algorithm is evaluated against the commercial AeroScout (WiFi-RFID) system and the ZigBee based Fingerprint algorithm

Advanced Map Matching Technologies and Techniques for Pedestrian/Wheelchair Navigation

Due to the constantly increasing technical advantages of mobile devices (such as smartphones), pedestrian/wheelchair navigation recently has achieved a high level of interest as one of smartphones’ potential mobile applications. While vehicle navigation systems have already reached a certain level of maturity, pedestrian/wheelchair navigation services are still in their infancy. By comparing vehicle navigation systems, a set of map matching requirements and challenges unique in pedestrian/wheelchair navigation is identified. To provide navigation assistance to pedestrians and wheelchair users, there is a need for the design and development of new map matching techniques. The main goal of this research is to investigate and develop advanced map matching technologies and techniques particular for pedestrian/wheelchair navigation services. As the first step in map matching, an adaptive candidate segment selection algorithm is developed to efficiently find candidate segments. Furthermore, to narrow down the search for the correct segment, advanced mathematical models are applied. GPS-based chain-code map matching, Hidden Markov Model (HMM) map matching, and fuzzy-logic map matching algorithms are developed to estimate real-time location of users in pedestrian/wheelchair navigation systems/services. Nevertheless, GPS signal is not always available in areas with high-rise buildings and even when there is a signal, the accuracy may not be high enough for localization of pedestrians and wheelchair users on sidewalks. To overcome these shortcomings of GPS, multi-sensor integrated map matching algorithms are investigated and developed in this research. These algorithms include a movement pattern recognition algorithm, using accelerometer and compass data, and a vision-based positioning algorithm to fill in signal gaps in GPS positioning. Experiments are conducted to evaluate the developed algorithms using real field test data (GPS coordinates and other sensors data). The experimental results show that the developed algorithms and the integrated sensors, i.e., a monocular visual odometry, a GPS, an accelerometer, and a compass, can provide high-quality and uninterrupted localization services in pedestrian/wheelchair navigation systems/services. The map matching techniques developed in this work can be applied to various pedestrian/wheelchair navigation applications, such as tracking senior citizens and children, or tourist service systems, and can be further utilized in building walking robots and automatic wheelchair navigation systems

Menu-Based User Interface Systems: Theory and Practice

The thesis discusses the menu selection technique, which is one of the most commonly used interaction techniques in Human-Computer Interfaces, and continues to flourish because of its simple interaction format and its adaptability to the many diverse applications. The ease of use of the technique, particularly by novices, contributes significantly to the widespread acceptance of menu-based user interface systems, despite their inherent disadvantages and drawbacks. Chapter One surveys the issues concerning the design and use of menu-based interfaces, and addresses particularly the navigational problems encountered by users of menu selection systems, identifying various navigational aids which help overcome these problems. The chapter concludes with a comparison between menu-based interfaces and other interface styles (command language, natural language and form-filling). Chapter Two describes the practical work of the thesis which consists of implementing a particularly demanding menu-based interface example involving multiple menu selections using four different dialogue specification systems. The implementation is discussed mainly from a menu system designer's view. Strategies to solve or address the multiple selection mechanism problem as well as some the navigational concepts discussed in chapter one are devised and used within each the four target systems. Also, some other related user interface design issues are reported in chapter two. The principal aim of the work is to investigate the difficulties a dialogue designer may face in attempting to implement a common type of menu-based interface using various delivery systems, all of which claim in varying degrees to support menu-based interactive styles. In the final chapter conclusions are drawn from the practical work concerning desirable menu support features in user interface implementation systems, and issues requiring further investigation are identified

Using a geographical information system to optimize access to primary health care services within the proposed New Hanover Health District.

Thesis (M.A.)-University of Natal, Pietermaritzburg, 1997.The health restructuring taking place within the health sector is a direct result of the unfolding socio-political processes presently sweeping across the country's very young democracy. The adoption of a Primary Health Care approach and the transition to a district-based health system is an attempt to bring the health services closer to the people and to correct or redress the way in which money is spent to keep people healthy. Given that 'in South Africa more people die from preventable diseases, a Primary Health Care approach is more appropriate to deal with the country's health needs. However, many also die from degenerative diseases such as heart disease, stroke and cancer and are dependent upon curative hospital-based care. Their health needs have to be catered for as well. Since the declaration of Alma Ata in 1978, the concept of Primary Health Care has been broadened to include other determinants of health such as water, sanitation and health education. As a result, collaboration with other service sectors became essential to support such a holistic view of health. The District Health System is the unit of management of the health system that is best able to compliment an intersectoral collaboration. The technology that is best suited to analyse health resources within a District Health System is a Geographical Information System. The delineation of the boundaries for the proposed New Hanover District Health System was essentially a consultative process. An assessment of the health resources within the proposed district revealed spatial inequalities between the areas of the former Republic of South Africa and the areas of the former Kwa-Zulu. The former Kwa-Zulu areas are disadvantaged in term of health care facilities, health care personnel, health services, water, sanitation, roads and economic opportunities.In collaboration with the Department of Health and the New Hanover Primary Health Care and Development Programme, five potential fixed clinic sites and two mobile clinic points were identified using a Geographical Information System. This study goes beyond considering population as the only and most important variable in the identification of potential sites. Other important variables such as the road network density, the number of primary schools and the number of mobile clinics within a 10 kilometre radius of each site were taken into consideration. The siting of the Khanyile and nKululueko mobile clinic points has demonstrated yet another way by which primary health care services could be made more accessible. Community participation was crucial in identifying and confirming each potential site. A mathematical formula named Pregan's PCs formula was specifically devised to determine the 'potentiality' of each site. For example, if the PCs value was less than one then the site was not considered. In the proposed New Hanover District Health System all sites were considered. The lack of health care facilities and lack of personnel along the densely populated eastern border of the proposed New Hanover District Health System were two major factors that affected access to primary health care services . It is envisaged that the five potential fixed clinic sites and the two mobile clinic points which were identified would help to improve access to primary health care services and at the same time redress the spatial inequalities that exist within the proposed health district. This study concluded that a Geographical Information System is a useful tool for addressing questions of access to primary health care services within a district-based health system

An evaluation of hypermedia information systems support for CNC machinists

As information technology (IT) capabilities increase, manufacturing businesses are realigning their information systems infrastructure to remain competitive. This has resulted in substantial increases in IT use in technical areas of the business. Nevertheless, conventional paper-based information systems are still common at the shopfloor. Hence, manufacturers need to understand whether there is any benefit in extending IT functionality to the shopfloor. The focus of this research is the support of the CNC machinist, who has a specific set of craft skills and knowledge that are a core business capability in the metal cutting industry. By evaluating the impact of hypermedia information systems upon the independent decision-making and communication capabilities of CNC machinists, this research aims to provide an understanding of the shopfloor performance benefits of replacing existing paper-based systems with this relatively new technology. This research finds that in CNC machining environments where there are limited divisions of labour, hypermedia-based manufacturing instructions support CNC machinist independent decision-making and cross-boundary communications as effective as paper-based manufacturing instructions. CNC machinists also demonstrate an acceptance of the new technology. Hence, the sponsor and the research community can pursue continued research to develop the technical and social systems to achieve predicted business benefits.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Semantic discovery and reuse of business process patterns

Patterns currently play an important role in modern information systems (IS) development and their use has mainly been restricted to the design and implementation phases of the development lifecycle. Given the increasing significance of business modelling in IS development, patterns have the potential of providing a viable solution for promoting reusability of recurrent generalized models in the very early stages of development. As a statement of research-in-progress this paper focuses on business process patterns and proposes an initial methodological framework for the discovery and reuse of business process patterns within the IS development lifecycle. The framework borrows ideas from the domain engineering literature and proposes the use of semantics to drive both the discovery of patterns as well as their reuse