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Publicações

2001

Loss minimization in distribution networks with multiple load scenarios

Autores
Matos, MA; Melo, P;

Publicação
2001 IEEE Porto Power Tech Proceedings

Abstract
In distribution networks, the problem of finding the radial configuration that minimizes losses is usually solved for the peak load scenario, since this is the worst case situation regarding both losses and network loading. In general, the solution will remain optimal for other load levels, provided that there is an homothetic load variation. However, in some situations, the load pattern in the entire network may change during the day, or in seasonal periods, leading to situations where the solution is not optimal outside the peak period, or outside a specific period. On the other hand, the presence of dispersed generation directly connected to the distribution network may also contribute to these situations. This paper addresses this issue by considering a set of load scenarios and finding single or multiple configuration solutions that minimize both energy losses and switching actions, in a bicriteria framework. The optimization engine uses a Simulated Annealing algorithm previously reported to give good results in this class of problem |1]|2|. The methodology is illustrated with an example. © 2001 IEEE.

2001

Discussion of "Integration of price cap and yardstick competition schemes in electrical distribution regulation"

Autores
Saraiva, JT; de Leao, MTP;

Publicação
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract

2001

Preliminary results from the MORE advanced control advice project for secure operation of isolated power systems with increased renewable energy penetration and storage

Autores
Hatziargyriou, N; Contaxis, G; Matos, M; Pecas Lopes, JA; Vasconcelos, MH; Kariniotakis, G; Mayer, D; Halliday, J; Dutton, G; Dokopoulos, P; Bakirtzis, A; Stefanakis, J; Gigantidou, A; O'Donnell, P; McCoy, D; Fernandes, MJ; Cotrim, JMS; Figueira, AP;

Publicação
2001 IEEE Porto Power Tech Proceedings

Abstract
In this paper, preliminary results from MORE CARE, a European R&D project financed within the Energy Program are described. This project has as main objective the development of an advanced control software system, aiming to optimize the overall performance of isolated and weakly interconnected systems in liberalized market environments by increasing the share of wind energy and other renewable forms, including advanced on-line security functions. The main features of the control system comprise advanced software modules for load and wind power forecasting, unit commitment and economic dispatch of the conventional and renewable units and on-line security assessment capabilities integrated in a friendly Man-Machine environment. Pilot installations of advanced control functions are foreseen on the islands of Crete, Ireland and Madeira. © 2001 IEEE.

2001

Simulated Annealing for the Unit Commitment problem

Autores
Viana, A; De Sousa, JP; Matos, M;

Publicação
2001 IEEE Porto Power Tech Proceedings

Abstract
Due to their efficiency and their interesting design and implementation features, metaheuristics have been used for a long time with success, in dealing with combinatorial problems. In recent years they have been applied to the Unit Commitment problem with rather interesting results that justify further research in the area. In this paper we present a Simulated Annealing approach to the Unit Commitment problem. Two coding schemes are compared, new neighbourhood structures are presented and some searching strategies are discussed. Preliminary computational experience, performed on some test instances, shows that this approach is flexible, effective and able to handle variations on the problem structure. © 2001 IEEE.

2001

A different approach to real web accessibility

Autores
Fernandes, AR; Martins, FM; Paredes, H; Pereira, JR;

Publicação
Universal Access In HCI: Towards an Information Society for All, Proceedings of HCI International '2001 (the 9th International Conference on Human-Computer Interaction), New Orleans, USA, August 5-10, 2001, Volume 3

Abstract

2000

Exploring alternative devices for blind users

Autores
Fernandes, AR; Paredes, H;

Publicação
VSMM 2000: 6TH INTERNATIONAL CONFERENCE ON VIRTUAL SYSTEMS AND MULTIMEDIA

Abstract
The ability to take advantage of the information society is becoming a must for everyone. Computer literacy is becoming more and more important for individuals as well as corporations. Therefore no efforts must be spared to integrate everyone in this new and exciting development, If for non-disabled persons this can be a challenge, for certain types of disabilities the effort of adaptation is huge. In this paper we focus on blind users. One of the current alternatives for blind users is based on specific hardware that tends to be limited in features and expansibility or very expensive. The other alternative is PC based software. This latest option, although very powerful, has also several disadvantages, namely the lack of practical mobility. In this paper we present a new approach the PalmPCs. PalmPCs are a cheap alternative compared to the hardware mentioned above, they are truly mobile, and they are widely available today. We argue that software can be written for these devices that satisfies the needs of the majority of the blind users. A small application for WindowsCE is presented in which the interface was specifically designed for blind users.

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