MASCEM Restructuring: Ontologies For Scenarios Generation in Power Systems Simulators

The electricity market restructuring, along with the increasing necessity for an adequate integration of renewable energy sources, is resulting in an rising complexity in power systems operation. Various power system simulators have been introduced in recent years with the purpose of helping operators, regulators, and involved players to understand and deal with this complex environment. This paper focuses on the development of an upper ontology which integrates the essential concepts necessary to interpret all the available information. The restructuring of MASCEM (Multi-Agent System for Competitive Electricity Markets), and this system’s integration with MASGriP (Multi-Agent Smart Grid Platform), and ALBidS (Adaptive Learning Strategic Bidding System) provide the means for the exemplification of the usefulness of this ontology. A practical example is presented, showing how common simulation scenarios for different simulators, directed to very distinct environments, can be created departing from the proposed ontology.

An Extension of Estimation of Domain of Attraction for Fractional Order Linear System Subject to Saturation Control

This paper employs the Lyapunov direct method for the stability analysis of fractional order linear systems subject to input saturation. A new stability condition based on saturation function is adopted for estimating the domain of attraction via ellipsoid approach. To further improve this estimation, the auxiliary feedback is also supported by the concept of stability region. The advantages of the proposed method are twofold: (1) it is straightforward to handle the problem both in analysis and design because of using Lyapunov method, (2) the estimation leads to less conservative results. A numerical example illustrates the feasibility of the proposed method.

Towards the Certification of Multicore Platforms in the Avionics Domain

Poster presented in Work in Progress Session, The 28th GI/ITG International Conference on Architecture of Computing Systems (ARCS 2015). 24 to 27, Mar, 2015. Porto, Portugal.

Towards the Certification of Multicore Platforms in the Avionics Domain

Presented at Work in Progress Session, The 28th GI/ITG International Conference on Architecture of Computing Systems (ARCS 2015). 24 to 27, Mar, 2015. Porto, Portugal.

Interactional strategies between terminologist and domain specialist. Putting order into our universe: the concept of Blended Learning

A presente comunicação visa discutir as mais-valias de um desenho metodológico sustentado numa abordagem conceptual da Terminologia aplicado ao exercício de harmonização da definição do cenário educativo mais promissor do Ensino Superior actual: o blended learning. Sendo a Terminologia uma disciplina que se ocupa da representação, da descrição e da definição do conhecimento especializado através da língua a essência deste domínio do saber responde a uma necessidade fundamental da sociedade actual: putting order into our universe, nas palavras de Nuopponen (2011). No contexto descrito, os conceitos, enquanto elementos da estrutura do conhecimento (Sager, 1990) constituem um objecto de investigação de complexidade não despicienda, pois apesar do postulado de que a língua constitui uma ferramenta fundamental para descrever e organizar o conhecimento, o princípio isomórfico não pode ser tomado como adquirido. A abordagem conceptual em Terminologia propõe uma visão precisa do papel da língua no trabalho terminológico, sendo premissa basilar que não existe uma correspondência unívoca entre os elementos atomísticos do conhecimento e os elementos da expressão linguística. É pela razões enunciadas que as opções metodológicas circunscritas à análise do texto de especialidade serão consideradas imprecisas. Nesta reflexão perspectiva-se que o conceito-chave de uma abordagem conceptual do trabalho terminológico implica a combinação de um processo de elicitação do conhecimento tácito através de uma negociação discursiva orientada para o conceito e a análise de corpora textuais. Defende-se consequentemente que as estratégias de interacção entre terminólogo e especialista de domínio merecem atenção detalhada pelo facto de se reflectirem com expressividade na qualidade dos resultados obtidos. Na sequência do exposto, o modelo metodológico que propomos sustenta-se em três etapas que privilegiam um refinamento dessa interacção permitindo ao terminólogo afirmar-se como sujeito conceptualizador, decisor e interventor: (1) etapa exploratória do domínio-objecto de estudo; (2) etapa de análise onamasiológica de evidência textual e discursiva; (3) etapa de modelização e de validação de resultados. Defender-se-á a produtividade de uma sequência cíclica entre a análise textual e discursiva para fins onomasiológicos, a interacção colaborativa e a introspecção.

Ontologies for the interoperability of multiagent electricity markets simulation platforms

Electricity markets worldwide are complex and dynamic environments with very particular characteristics. These are the result of electricity markets’ restructuring and evolution into regional and continental scales, along with the constant changes brought by the increasing necessity for an adequate integration of renewable energy sources. The rising complexity and unpredictability in electricity markets has increased the need for the intervenient entities in foreseeing market behaviour. Market players and regulators are very interested in predicting the market’s behaviour. Market players need to understand the market behaviour and operation in order to maximize their profits, while market regulators need to test new rules and detect market inefficiencies before they are implemented. The growth of usage of simulation tools was driven by the need for understanding those mechanisms and how the involved players' interactions affect the markets' outcomes. Multi-agent based software is particularly well fitted to analyse dynamic and adaptive systems with complex interactions among its constituents, such as electricity markets. Several modelling tools directed to the study of restructured wholesale electricity markets have emerged. Still, they have a common limitation: the lack of interoperability between the various systems to allow the exchange of information and knowledge, to test different market models and to allow market players from different systems to interact in common market environments. This dissertation proposes the development and implementation of ontologies for semantic interoperability between multi-agent simulation platforms in the scope of electricity markets. The added value provided to these platforms is given by enabling them sharing their knowledge and market models with other agent societies, which provides the means for an actual improvement in current electricity markets studies and development. The proposed ontologies are implemented in MASCEM (Multi-Agent Simulator of Competitive Electricity Markets) and tested through the interaction between MASCEM agents and agents from other multi-agent based simulators. The implementation of the proposed ontologies has also required a complete restructuring of MASCEM’s architecture and multi-agent model, which is also presented in this dissertation. The results achieved in the case studies allow identifying the advantages of the novel architecture of MASCEM, and most importantly, the added value of using the proposed ontologies. They facilitate the integration of independent multi-agent simulators, by providing a way for communications to be understood by heterogeneous agents from the various systems.