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- Cooperation in Learning Power Systems Restoration TechniquesPublication . Silva, António; Ramos, Carlos; Vale, Zita; Ramos, Carlos; Vale, ZitaAdequate training programs for power systems restoration tasks must take into account that this is a cooperative activity involving several entities. The proposed architecture of the Intelligent Tutoring System presented in this paper is based on a multi-agent system offering a simulated training environment.
- On the Verification of Expert Systems: A case study on the Power Systems AreaPublication . Santos, Jorge; Ramos, Carlos; Vale, Zita; Ramos, Carlos; Vale, ZitaThe Verification and Validation (V&V) process states if the software requirements specifications have been correctly and completely fulfilled. The methodologies proposed in software engineering showed to be inadequate for Knowledge Based Systems (KBS) validation and verification, since KBS present some particular characteristics. Designing KBS for dynamic environments requires the consideration of Temporal knowledge Reasoning and Representation (TRR) issues. ‘Although humans present a natural ability to deal with knowledge about time and events, the codification and use of such knowledge in information systems still pose many problems. Hence, the development of applications strongly based on temporal reasoning remains an hard and complex task. Furthermore, albeit the last significant developments in TRR area, there is still a considerable gap for its successful use in practical applications. VERITAS is an automatic tool developed for KBS verification which is able to detect a large number of knowledge anomalies. It addresses many relevant aspects considered in real applications, like the usage of rule triggering selection mechanisms and temporal reasoning. VERITAS is currently in development and is being tested with SPARSE, a KBS used in the Portuguese Transmission Network (REN) for incident analysis and power restoration. In this paper some solutions are proposed for still open issues on Verification of KBS applied in critical domains.
- Webmeeting – A group decision support system for multicriteria decision problemsPublication . Sousa, Jorge Pinho de; Marreiros, Goreti; Ramos, Carlos; Ramos, Carlos; Vale, ZitaWebMeeting is a Group Decision Support System designed to support distributed and asynchronous meetings. It aims at helping geographically distributed people and organisations in solving multi-criteria decision problems, by allowing their participation in the decision process through the Internet. This paper presents the WebMeeting architecture, as well as its main functionalities, namely the selection of alternatives, argumentation, voting techniques and meeting setup.
- Defining a model for agent-based participant support in group decision meetingPublication . Marreiros, Goreti; Ramos, Carlos; Neves, José; Ramos, Carlos; Vale, ZitaThis paper aim to present a multi-agent model for a simulation system, whose goal is to help one specific participant of multi-criteria group decision making process. This model has five main intervenients types: the human participant, who is using the simulation and argumentation support system; the participant agents, one associated to the human participant and the others simulating the others members of the decision meeting group; the directory agent; the proposal agents, representing the different alternatives for a decision (the alternatives are evaluated based on criteria); and the voting agent responsible for all the voting mechanisms. At this stage it is proposed a two phase algorithm. In the first phase each participant agent makes his own evaluation of the proposals under discussion, and the voting agent proposes a simulation of a voting. In second phase, after the dissemination of the voting results, each one of the participant agents will argue to convince the others to choose one of the possible alternatives. The arguments used to convince a specific participant are dependent on agent knowledge about that participant. The two-phase algorithm is applied iteratively.
- An agent-based approach to support decisions on electronic marketplacesPublication . Viamonte, Maria João; Ramos, Carlos; Rodrigues, Maria de Fátima Coutinho; Cardoso, José; Ramos, Carlos; Vale, ZitaWith the increasing importance of Electronic Commerce across the Internet the need for software agents to support both customers and suppliers in buying and selling goods/services is growing rapidly. It is becoming increasingly evident that in a few years the Internet will host a large number of interacting software agents. Most of them will be economically motivated, and will negotiate a variety of goods and services. It is therefore important to consider the economic incentives and behaviours of economic software agents, and to use all available means to anticipate their collective interactions. This paper addresses this concern by presenting a Market Simulator designed for analysing agent market strategies based on a complete understanding of buyer and seller behaviours, preference models and pricing algorithms. The system includes agents that are capable of increasing their performance with their own experience, by adapting to the market conditions. The results of the negotiations between agents will be analysed by Data mining tools in order to extract rules that will give the agents feedback to improve their strategies. We will describe the characteristics and technologies involved in the architecture we are specifying and developing.
- Fabricare: an agent-based system for manufacturingPublication . Sousa, Paulo; Neves, José; Ramos, Carlos; Ramos, Carlos; Vale, ZitaDue to current and future trends in manufacturing, computer-supported manufacturing systems are now more distributed than the traditional CIM approach. This paper presents a prototype system for the problem of scheduling of manufacturing orders, focusing on the internal implementation of each type of agent in the system.
- Distributed intelligent tutoring system for control centre operators trainingPublication . Faria, Luiz; Ramos, Carlos; Vale, Zita; Ramos, Carlos; Vale, ZitaThe new requirements of power systems operation demand experienced and well trained operators. However, the training is not often considered a priority task, due mostly to its high costs and medium/long term results. Usually, the training programs available in industrial environment do not consider the particular training needs of each trainee. The application of the Intelligent Tutoring technology has proved to be a good alternative to the existing training approaches in the power systems area. This paper presents a Web-based Intelligent Tutoring System (ITS) to train Control Centre operators of the Portuguese electrical transmission network. One of the major advantages of the training based on the ITS technology is the ability to provide individualized training. To achieve this, our ITS maintains a trainee model, which models the trainee’s understanding of domain concepts. In this way, the paper describes a curriculum planning module used to choose the most appropriate problem to the trainee’s knowledge status. This module includes a neural network to perform a classification of each type of incident according to the trainee’s current knowledge. This paper also deals with a mechanism developed to obtain the trainee’s reasoning during problem solving.
- A multi-agent system to support decision making in electricity marketsPublication . Praça, Isabel; Ramos, Carlos; Vale, Zita; Cordeiro, Manuel; Ramos, Carlos; Vale, ZitaThroughout the world, the electricity industry is undergoing enormous changes in the structure of its markets and their regulations. The electricity industry is evolving into a distributed and competitive industry in which market forces drive the price of electricity. Changes are towards a competitive framework and a market environment is replacing the traditional centralized operation approach. As electricity markets evolve there is a need for new modelling approaches that simulate how electric power markets could evolve over time and how participants in these markets may act and react to the changing economic, financial and regulatory environment in which they operate. In this paper we present a Multi-Agent simulator to give decision support in Competitive Electricity Markets combining bilateral trading with power exchange mechanisms. This Multi-Agent environment includes several heterogeneous and autonomous intelligent agents, which are endowed with historical information about the market and have strategic behaviour to negotiate. This paper focuses on the different negotiation mechanisms supported by the simulator, and on agents’ strategic behaviour to face them. A special attention is devoted to the structure of market players, Seller and Buyer agents, particularly in what concerns their decision analysis process to face the challenging market.
- Characterization of mv consumers using hierarchical clusteringPublication . Figueiredo, V.; Pinheiro, R.; Carvalho Ramos, Sérgio Filipe; Rodrigues, Maria de Fátima Coutinho; Vale, Zita; Ramos, Carlos; Vale, ZitaWith the electricity market liberalization, distribution and retail companies are looking for better market strategies based on adequate information upon the consumption patterns of its electricity customers. A fair insight on the customers’ behaviour will permit the definition of specific contract aspects based on the different, consumption patterns. In this paper, we propose a Knowledge Discovery in Databases project applied to electricity consumption data from a utility client’s database. To form the different customers’ classes, and find a set of representative consumption patterns, we have used the Two-Step algorithm which is a hierarchical clustering algorithm. Each consumer class will be represented by its load profile resulting from the clustering operation. Next, to characterize each consumer class a classification model will be constructed with the C5.0 classification algorithm.
- Hybrid methods for the maintenance scheduling of generating units problemPublication . Gomes, Nuno; Cordeiro, Manuel; Vale, Zita; Ramos, Carlos; Ramos, Carlos; Vale, ZitaReal world search and optimization problems are usually characterized by having large search spaces, being difficult to model and being constantly changing. Constraint Logic Programming (CLP) has proved to be a good tool to model and solve this type of problems despite some efficiency problems. It seams that the problem is related to some lack of a “global perspective” of the constraints in the search process, One way of overcoming this problem is to hybridize Constraint Logic Programming with Linear Programming (LP) in order to enhance the solving process by finding feasible solutions early in the search by “global reasoning”. In this work we propose 4 hybrid methods for solving a Maintenance Scheduling of Generating Units problem. The main idea is to take the advantages of both CLP and LP avoiding their problems. Some initial tests show that for some conditions all the hybrid methods can perform better than CLP alone.