Abstract
Very often, in dependability evaluation, the systems under study are assumed to have a Markovian behavior. This assumption highly simplifies the calculations, but introduces significant errors when the systems contain deterministic or quasi-deterministic processes, as it often happens with industrial systems. Existing methodologies for non-Markovian systems, such as device stage method [1], the supplementary variables method or the imbedded Markov chain method [2] do not provide an effective solution to deal with this class of systems, since their usage is restricted to relatively simple and small systems. This paper presents an analytical methodology for the dependability evaluation of non-Markovian discrete state systems, containing both stochastic and deterministic processes, along with an associated systematic resolution procedure suitable for numerical processing. The methodology was initially developed in the context of a research work [3] addressing the dependability modeling, analysis and evaluation of large industrial information systems. This paper, extends the application domain to the evaluation of reliability oriented indexes and to the assessment of multiple components systems. Examples will be provided throughout the paper, in order to illustrate the fundamental concepts of the methodology, and to demonstrate its practical usefulness.

Abstract
The 2001 PowerTech Conference held in Porto, Portugal from 10 to 13 September, provided an international forum for participants to share knowledge, experiences, and new ideas about the changes in the electronic power sector. The Conference was attended by more than 450 delegates from 50 countries.

Abstract

Abstract
In this paper, we present a prototype of a DMS -Distribution Management System - using Object Oriented technology and a modular distributed multitask client-server architecture. The DMS is supported by an Object Oriented model in which the power system components are considered objects grouped in several classes according to their characteristics. The power system applications are software modules within this base platform that is physically located in a WEB server and are implemented in Java or C++. The users should connect to an HTML page in the server, download the desired applet to the client's machine establishing communication, interfaces and requesting services to the main system. The paper gives a global overview of the system, describes its architecture, gives details about the Database organization and describes the main characteristics and features of some power system applications as Topology Processor, Single Phase Power Flow and Symmetric Short Circuit. © 2001 IEEE.

Abstract
In the scope of a consultancy study conducted by the Power Systems Unit of INESC Porto, the yearly regulated remuneration of the Portuguese transmission provider was allocated to the network users considering an approach based on power-flow embedded methods. The tested cost allocation methods were the MW.mile, the Modulus and the Zero Counterflow. The application of that approach lead to geographically discriminated Tariffs for Use of Transmission Networks. This study must be considered as a contribution to the revision process of the current regulations when the first regulatory period is about to end. It should be emphasized that it was not the purpose of this study to question the current Cost of Service/Rate of Return strategy in force in the Portuguese transmission sector and to calculate the adequate yearly remuneration of the transmission provider. The only objective of this study was to simulate the application of alternative cost allocation approaches, given that the whole amount to allocate is fixed by current rules. In this way, we think it is possible to contribute to a more technically sounded discussion about the advantages and drawbacks of several approaches. © 2001 IEEE.

Abstract
In the scope of the revision of the Portuguese Tariff Regulation, the Power Systems Unit of INESC Porto concluded a consultancy study aiming at estimating the remuneration that could be obtained by the Portuguese transmission provider using Short Term Marginal Prices. This paper describes the main principles behind the regulation of the transmission sector in force in Portugal, details the model used to compute the nodal marginal prices in the transmission network, presents a comprehensive set of results for some scenarios in which the year was organized as well as the estimate of the referred remuneration. The data of the scenarios that were used is publicly available in [l] and we adopted typical values for generation costs of different thermal plants. At the end, the paper includes some conclusions as well as some ideas of hture work aiming at improving the quality of the estimate of the marginal based remuneration. © 2001 IEEE.