Aplicação de sistema especialista para localização de defeitos em redes de distribuição.

Com o objetivo de orientar e agilizar a busca do local de curto circuitos em redes primárias aéreas de distribuição de energia, esta pesquisa propõe uma metodologia para localização de áreas com maior probabilidade de ser sede do defeito, utilizando variáveis Heurísticas. A metodologia Heurística se aplica em problemas que envolvem variáveis com incertezas, que podem ser avaliadas por meio de recursos empíricos e na experiência de especialistas. Dentre as variáveis influentes no cálculo de curto circuito, foram consideradas como mais relevantes: a resistência de defeito, a tensão pré falta, a impedância do sistema equivalente a montante da subestação e a impedância da rede. A metodologia proposta se fundamenta no conhecimento das correntes e tensões oscilografadas no barramento da subestação por ocasião da ocorrência de um curto circuito e, por outro lado no pré-calculo de correntes de curto circuito heurísticas ao longo da rede. No âmbito da pesquisa foram realizados testes de campo para levantamento da variável heurística resistência de defeito, resumidos neste texto e documentados no CD - ROM em anexo. Foi desenvolvido um software que permitiu a efetiva aplicação da proposta desta pesquisa em vários alimentadores de uma Distribuidora, cujos resultados comprovaram a eficiência da metodologia.

Sistema especialista para análise pós-evento da proteção em subestações distribuidoras.

É importante que as redes elétricas tenham altos índices de confiabilidade, de forma a se manter a agilidade e a manutenção ideais para um melhor funcionamento. Por outro lado, o crescimento inesperado da carga, falhas em equipamentos e uma parametrização inadequada das funções de proteção tornam a análise de eventos de proteção mais complexas e demoradas. Além disso, a quantidade de informações que pode ser obtida de relés digitais modernos tem crescido constantemente. Para que seja possível uma rápida tomada de decisão e manutenção, esse projeto de pesquisa teve como objetivo a implementação de um sistema completo de diagnóstico que é ativado automaticamente quando um evento de proteção ocorrer. As informações a serem analisadas são obtidas de uma base de dados e de relés de proteção, via protocolo de comunicação IEC 61850 e arquivos de oscilografia. O trabalho aborda o sistema Smart Grid completo incluindo: a aquisição de dados nos relés, detalhando o sistema de comunicação desenvolvido através de um software com um cliente IEC61850 e um servidor OPC e um software com um cliente OPC, que é ativado por eventos configurados para dispará-lo (por exemplo, atuação da proteção); o sistema de pré-tratamento de dados, onde os dados provenientes dos relés e equipamentos de proteção são filtrados, pré-processados e formatados; e o sistema de diagnóstico. Um banco de dados central mantém atualizados os dados de todas essas etapas. O sistema de diagnóstico utiliza algoritmos convencionais e técnicas de inteligência artificial, em particular, um sistema especialista. O sistema especialista foi desenvolvido para lidar com diferentes conjuntos de dados de entrada e com uma possível falta de dados, sempre garantindo a entrega de diagnósticos. Foram realizados testes e simulações para curtos-circuitos (trifásico, dupla-fase, dupla-fase-terra e fase-terra) em alimentadores, transformadores e barras de uma subestação. Esses testes incluíram diferentes estados do sistema de proteção (funcionamento correto e impróprio). O sistema se mostrou totalmente eficaz tanto no caso de disponibilidade completa quanto parcial de informações, sempre fornecendo um diagnóstico do curto-circuito e analisando o funcionamento das funções de proteção da subestação. Dessa forma, possibilita-se uma manutenção muito mais eficiente pelas concessionárias de energia, principalmente no que diz respeito à prevenção de defeitos em equipamentos, rápida resposta a problemas, e necessidade de reparametrização das funções de proteção. O sistema foi instalado com sucesso em uma subestação de distribuição da Companhia Paulista de Força e Luz.

Hybrid knowledge representation in a blackboard KBS for liquid retaining structure design

This paper highlights the importance of design expertise, for designing liquid retaining structures, including subjective judgments and professional experience. Design of liquid retaining structures has special features different from the others. Being more vulnerable to corrosion problem, they have stringent requirements against serviceability limit state of crack. It is the premise of the study to transferring expert knowledge in a computerized blackboard system. Hybrid knowledge representation schemes, including production rules, object-oriented programming, and procedural methods, are employed to express engineering heuristics and standard design knowledge during the development of the knowledge-based system (KBS) for design of liquid retaining structures. This approach renders it possible to take advantages of the characteristics of each method. The system can provide the user with advice on preliminary design, loading specification, optimized configuration selection and detailed design analysis of liquid retaining structure. It would be beneficial to the field of retaining structure design by focusing on the acquisition and organization of expert knowledge through the development of recent artificial intelligence technology. (C) 2003 Elsevier Ltd. All rights reserved.

Computer simulation of form-roll design

Changes in modern structural design have created a demand for products which are light but possess high strength. The objective is a reduction in fuel consumption and weight of materials to satisfy both economic and environmental criteria. Cold roll forming has the potential to fulfil this requirement. The bending process is controlled by the shape of the profile machined on the periphery of the rolls. A CNC lathe can machine complicated profiles to a high standard of precision, but the expertise of a numerical control programmer is required. A computer program was developed during this project, using the expert system concept, to calculate tool paths and consequently to expedite the procurement of the machine control tapes whilst removing the need for a skilled programmer. Codifying the expertise of a human and the encapsulation of knowledge within a computer memory, destroys the dependency on highly trained people whose services can be costly, inconsistent and unreliable. A successful cold roll forming operation, where the product is geometrically correct and free from visual defects, is not easy to attain. The geometry of the sheet after travelling through the rolling mill depends on the residual strains generated by the elastic-plastic deformation. Accurate evaluation of the residual strains can provide the basis for predicting the geometry of the section. A study of geometric and material non-linearity, yield criteria, material hardening and stress-strain relationships was undertaken in this research project. The finite element method was chosen to provide a mathematical model of the bending process and, to ensure an efficient manipulation of the large stiffness matrices, the frontal solution was applied. A series of experimental investigations provided data to compare with corresponding values obtained from the theoretical modelling. A computer simulation, capable of predicting that a design will be satisfactory prior to the manufacture of the rolls, would allow effort to be concentrated into devising an optimum design where costs are minimised.

The investigation of crime:the myths and the reality

Initially the study focussed on the factors affecting the ability of the police to solve crimes. An analysts of over twenty thousand police deployments revealed the proportion of time spent investigating crime contrasted to its perceived importance and the time spent on other activities. The fictional portrayal of skills believed important in successful crime investigation were identified and compared to the professional training and 'taught skills’ given to police and detectives. Police practitioners and middle management provided views on the skills needed to solve crimes. The relative importance of the forensic science role. fingerprint examination and interrogation skills were contrasted with changes in police methods resulting from the Police and Criminal Evidence Act and its effect on confessions. The study revealed that existing police systems for investigating crime excluding specifically cases of murder and other serious offences, were unsystematic, uncoordinated, unsupervised and unproductive in using police resources. The study examined relevant and contemporary research in the United States and United Kingdom and with organisational support introduced an experimental system of data capture and initial investigation with features of case screening and management. Preliminary results indicated increases in the collection of essential information and more effective use of investigative resources. In the managerial framework within which this study has been conducted, research has been undertaken in the knowledge elicitation area as a basis for an expert system of crime investigation and the potential organisational benefits of utilising the Lap computer in the first stages of data gathering and investigation. The conclusions demonstrate the need for a totally integrated system of criminal investigation with emphasis on an organisational rather than individual response. In some areas the evidence produced is sufficient to warrant replication, in others additional research is needed to further explore other concepts and proposed systems pioneered by this study.

Developing a model for consumer product safety evaluation

Safety enforcement practitioners within Europe and marketers, designers or manufacturers of consumer products need to determine compliance with the legal test of "reasonable safety" for consumer goods, to reduce the "risks" of injury to the minimum. To enable freedom of movement of products, a method for safety appraisal is required for use as an "expert" system of hazard analysis by non-experts in safety testing of consumer goods for implementation consistently throughout Europe. Safety testing approaches and the concept of risk assessment and hazard analysis are reviewed in developing a model for appraising consumer product safety which seeks to integrate the human factors contribution of risk assessment, hazard perception, and information processing. The model develops a system of hazard identification, hazard analysis and risk assessment which can be applied to a wide range of consumer products through use of a series of systematic checklists and matrices and applies alternative numerical and graphical methods for calculating a final product safety risk assessment score. It is then applied in its pilot form by selected "volunteer" Trading Standards Departments to a sample of consumer products. A series of questionnaires is used to select participating Trading Standards Departments, to explore the contribution of potential subjective influences, to establish views regarding the usability and reliability of the model and any preferences for the risk assessment scoring system used. The outcome of the two stage hazard analysis and risk assessment process is considered to determine consistency in results of hazard analysis, final decisions regarding the safety of the sample product and to determine any correlation in the decisions made using the model and alternative scoring methods of risk assessment. The research also identifies a number of opportunities for future work, and indicates a number of areas where further work has already begun.

Predicting and diagnosing faults in wastewater treatment process by Bayesian Belief Networks

Diagnosing faults in wastewater treatment, like diagnosis of most problems, requires bi-directional plausible reasoning. This means that both predictive (from causes to symptoms) and diagnostic (from symptoms to causes) inferences have to be made, depending on the evidence available, in reasoning for the final diagnosis. The use of computer technology for the purpose of diagnosing faults in the wastewater process has been explored, and a rule-based expert system was initiated. It was found that such an approach has serious limitations in its ability to reason bi-directionally, which makes it unsuitable for diagnosing tasks under the conditions of uncertainty. The probabilistic approach known as Bayesian Belief Networks (BBNS) was then critically reviewed, and was found to be well-suited for diagnosis under uncertainty. The theory and application of BBNs are outlined. A full-scale BBN for the diagnosis of faults in a wastewater treatment plant based on the activated sludge system has been developed in this research. Results from the BBN show good agreement with the predictions of wastewater experts. It can be concluded that the BBNs are far superior to rule-based systems based on certainty factors in their ability to diagnose faults and predict systems in complex operating systems having inherently uncertain behaviour.

Computer automation of land evaluation procedures

This study was concerned with the computer automation of land evaluation. This is a broad subject with many issues to be resolved, so the study concentrated on three key problems: knowledge based programming; the integration of spatial information from remote sensing and other sources; and the inclusion of socio-economic information into the land evaluation analysis. Land evaluation and land use planning were considered in the context of overseas projects in the developing world. Knowledge based systems were found to provide significant advantages over conventional programming techniques for some aspects of the land evaluation process. Declarative languages, in particular Prolog, were ideally suited to integration of social information which changes with every situation. Rule-based expert system shells were also found to be suitable for this role, including knowledge acquisition at the interview stage. All the expert system shells examined suffered from very limited constraints to problem size, but new products now overcome this. Inductive expert system shells were useful as a guide to knowledge gaps and possible relationships, but the number of examples required was unrealistic for typical land use planning situations. The accuracy of classified satellite imagery was significantly enhanced by integrating spatial information on soil distribution for Thailand data. Estimates of the rice producing area were substantially improved (30% change in area) by the addition of soil information. Image processing work on Mozambique showed that satellite remote sensing was a useful tool in stratifying vegetation cover at provincial level to identify key development areas, but its full utility could not be realised on typical planning projects, without treatment as part of a complete spatial information system.

Knowledge Presentation and Reasoning with Loglinear Models

Our approach for knowledge presentation is based on the idea of expert system shell. At first we will build a graph shell of both possible dependencies and possible actions. Then, reasoning by means of Loglinear models, we will activate some nodes and some directed links. In this way a Bayesian network and networks presenting loglinear models are generated.

Telehealth Approach for Glaucoma Progression Monitoring

This paper presents a Web-Centric [3] extension to a previously developed glaucoma expert system that will provide access for doctors and patients from any part of the world. Once implemented, this telehealth solution will publish the services of the Glaucoma Expert System on the World Wide Web, allowing patients and doctors to interact with it from their own homes. This web-extension will also allow the expert system itself to be proactive and to send diagnosis alerts to the registered user or doctor and the patient, informing each one of any emergencies, therefore allowing them to take immediate actions. The existing Glaucoma Expert System uses fuzzy logic learning algorithms applied on historical patient data to update and improve its diagnosis rules set. This process, collectively called the learning process, would benefit greatly from a web-based framework that could provide services like patient data transfer and web- based distribution of updated rules [1].

Knowledge Construction Technology through Hypermedia-Based Intelligent Conversational Channel

There have been multifarious approaches in building expert knowledge in medical or engineering field through expert system, case-based reasoning, model-based reasoning and also a large-scale knowledge-based system. The intriguing factors with these approaches are mainly the choices of reasoning mechanism, ontology, knowledge representation, elicitation and modeling. In our study, we argue that the knowledge construction through hypermedia-based community channel is an effective approach in constructing expert’s knowledge. We define that the knowledge can be represented as in the simplest form such as stories to the most complex ones such as on-the-job type of experiences. The current approaches of encoding experiences require expert’s knowledge to be acquired and represented in rules, cases or causal model. We differentiate the two types of knowledge which are the content knowledge and socially-derivable knowledge. The latter is described as knowledge that is earned through social interaction. Intelligent Conversational Channel is the system that supports the building and sharing on this type of knowledge.

A Log Tool for Software Systems Analyses

The article presents a new type of logs merging tool for multiple blade telecommunication systems based on the development of a new approach. The introduction of the new logs merging tool (the Log Merger) can help engineers to build a processes behavior timeline with a flexible system of information structuring used to assess the changes in the analyzed system. This logs merging system based on the experts experience and their analytical skills generates a knowledge base which could be advantageous in further decision-making expert system development. This paper proposes and discusses the design and implementation of the Log Merger, its architecture, multi-board analysis of capability and application areas. The paper also presents possible ways of further tool improvement e.g. - to extend its functionality and cover additional system platforms. The possibility to add an analysis module for further expert system development is also considered.

Transformada wavelet aplicada a análise automática de oscilografias de curta duração em unidades geradoras

The focus of this work is the automatic analysis of disturbance records for electrical power generating units. The main proposition is a method based on wavelet transform applied to short-term disturbance records (waveform records). The goal of the method is to detect the time instants of recorded disturbances and extract meaningful information that characterize the faults. The result is a set of representative information of the monitored signals in power generators. This information can be further classified by an expert system (or other classification method) in order to classify the faults and other abnormal operating conditions. The large amount of data produced by digital fault recorders during faults justify the research of methods to assist the analysts in their task of analysing the disturbances. The literature review pointed out the state of the art and possible applications for oscillography records. The review of the COMTRADE standard and wavelet transform underlines the choice of the method for solving the problem. The conducted tests lead to the determination of the best mother wavelet for the segmentation process. The application of the proposed method to five case studies with real oscillographic records confirmed the accuracy and efficiency of the proposed scheme. With this research, the post-operation analysis of occurrences is improved and as a direct result is the reduction of the time that generators are offline.

A RBES for Generating Automatically Personalized Menus

Food bought at supermarkets in, for instance, North America or the European Union, give comprehensive information about ingredients and allergens. Meanwhile, the menus of restaurants are usually incomplete and cannot be normally completed by the waiter. This is specially important when traveling to countries with a di erent culture. A curious example is "calamares en su tinta" (squid in its own ink), a common dish in Spain. Its brief description would be "squid with boiled rice in its own (black) ink", but an ingredient of its sauce is flour, a fact very important for celiacs. There are constraints based on religious believes, due to food allergies or to illnesses, while others just derive from personal preferences. Another complicated situation arise in hospitals, where the doctors' nutritional recommendations have to be added to the patient's usual constraints. We have therefore designed and developed a Rule Based Expert System (RBES) that can address these problems. The rules derive directly from the recipes of the di fferent dishes and contain the information about the required ingredients and ways of cooking. In fact, we distinguish: ingredients and ways of cooking, intermediate products (like sauces, that aren't always made explicit) and final products (the dishes listed in the menu of the restaurant). For a certain restaurant, customer and instant, the input to the RBES are: actualized stock of ingredients and personal characteristics of that customer. The RBES then prepares a "personalized menu" using set operations and knowledge extraction (thanks to an algebraic inference engine [1]). The RBES has been implemented in the computer algebra system MapleTM2015. A rst version of this work was presented at "Applications of Computer Algebra 2015" (ACA'2015) conference. The corresponding abstract is available at [2].