Modelação computacional baseada em agentes : enfrentar a complexidade

A análise dos sistemas sociais e dinâmicos assiste a uma mudança de paradigma, dos métodos matemáticos tradicionais para a simulação baseada em agentes. Trata-se de uma nova linha de pensar, interdisciplinar, onde abundam inovações metodológicas e conceptuais, e onde se criam sociedades artificiais com agentes individuais e inteligentes que se comportam como seres humanos muito simples e plausíveis. Neste artigo abordam-se os modelos desses agentes e os modos como regras simples de interacção social local geram explicações de comportamentos complexos. Através de dois exemplos (inovação tecnológica num parque de ciência e desenho de políticas de tributação), mostra-se como as ferramentas Swarm e NetLogo foram exploradas para modelar os mundos reais.The analysis of social and dynamical systems faces a paradigm shift, from mathematical methods to agent-based simulation. It is a new line of thinking, multidisciplinary, where technological and conceptual innovations grow, and where artificial societies of individual and intelligent agents are generated to replicate simple and plausible human beings. This paper deals with agent models and the ways how simple rules of social interaction grow explanations of complex behaviors. Through two examples (technological innovation in a science park and design of tax compliance policies) we show how Swarm and NetLogo tools were explored to model real worlds.peerreviewe

Program conversing in Portugese providing a library service

TUGA is a program which converses in Portuguese to provide a library service covering the field of Artificial Intelligence. The objective of designing the program TUGA was the development of a feasible method for consulting and creating data bases in natural Portuguese. The resulting program allows dialogues where the program and its users behave in the way humans normally do in a dialogue setting. The program can answer/ and question in pre-defined scenarios. Users can question/ answer and issue commands in a natural and convenient way/ without bothering excessively with the form of the dialogues and sentences. The original contributions of this work are: the treatment of dialogues. the adaptation of Colmerauer's natural language framework to Portuguese, the particular method for evaluating the logical structures involved in Colmerauer's framework, and the library service application itself. The program is implemented in Prolog, a simple and surprisingly powerful programming language essentially identical in syntax and semantics to a subset of predicate calculus in clausal form

Decisions with multiple simultaneous goals and uncertain causal effects

A key aspect of decision-making in a disaster response scenario is the capability to evaluate multiple and simultaneously perceived goals. Current competing approaches to build decision-making agents are either mental-state based as BDI, or founded on decision-theoretic models as MDP. The BDI chooses heuristically among several goals and the MDP searches for a policy to achieve a specific goal. In this paper we develop a preferences model to decide among multiple simultaneous goals. We propose a pattern, which follows a decision-theoretic approach, to evaluate the expected causal effects of the observable and non-observable aspects that inform each decision. We focus on yes-or-no (i.e., pursue or ignore a goal) decisions and illustrate the proposal using the RoboCupRescue simulation environment

The Logic of the Method of Agent-Based Simulation in the Social Sciences: Empirical and Intentional Adequacy of Computer Programs

The classical theory of computation does not represent an adequate model of reality for simulation in the social sciences. The aim of this paper is to construct a methodological perspective that is able to conciliate the formal and empirical logic of program verification in computer science, with the interpretative and multiparadigmatic logic of the social sciences. We attempt to evaluate whether social simulation implies an additional perspective about the way one can understand the concepts of program and computation. We demonstrate that the logic of social simulation implies at least two distinct types of program verifications that reflect an epistemological distinction in the kind of knowledge one can have about programs. Computer programs seem to possess a causal capability (Fetzer, 1999) and an intentional capability that scientific theories seem not to possess. This distinction is associated with two types of program verification, which we call empirical and intentional verification. We demonstrate, by this means, that computational phenomena are also intentional phenomena, and that such is particularly manifest in agent-based social simulation. Ascertaining the credibility of results in social simulation requires a focus on the identification of a new category of knowledge we can have about computer programs. This knowledge should be considered an outcome of an experimental exercise, albeit not empirical, acquired within a context of limited consensus. The perspective of intentional computation seems to be the only one possible to reflect the multiparadigmatic character of social science in terms of agent-based computational social science. We contribute, additionally, to the clarification of several questions that are found in the methodological perspectives of the discipline, such as the computational nature, the logic of program scalability, and the multiparadigmatic character of agent-based simulation in the social sciences.Computer and Social Sciences, Agent-Based Simulation, Intentional Computation, Program Verification, Intentional Verification, Scientific Knowledge

Paratuberculose caprina: seroprevalência de Mycobacterium avium subsp. paratuberculosis (Map) em caprinos no nordeste de Portugal e principais fatores associados: resultados preliminares

A paratuberculose apresenta elevada seroprevalência em caprinos no nordeste de Portugal. Foi efectuado um estudo epidemiológico em 95 explorações caprinas do nordeste de Portugal para a deteção de anticorpos contra Mycobacterium avium subsp. Paratuberculosis usando um ensaio imunoenzimático comercial (kit ELISA). Através da realização de inquéritos nas explorações estudaram-se os principais factores de risco presentes nas explorações.info:eu-repo/semantics/publishedVersio

An Analysis of the Insertion of Virtual Players in GMABS Methodology Using the Vip-JogoMan Prototype

The GMABS (Games and Multi-Agent-Based Simulation) methodology was created from the integration of RPG and MABS techniques. This methodology links the dynamic capacity of MABS (Multi-Agent-Based Simulation) and the discussion and learning capacity of RPG (Role-Playing Games). Using GMABS, we have developed two prototypes in the natural resources management domain. The first prototype, called JogoMan (Adamatti et. al, 2005), is a paper-based game: all players need to be physically present in the same place and time, and there is a minimum needed number of participants to play the game. In order to avoid this constraint, we have built a second prototype, called ViP-JogoMan (Adamatti et. al, 2007), which is an extension of the first one. This second game enables the insertion of virtual players that can substitute some real players in the game. These virtual players can partially mime real behaviors and capture autonomy, social abilities, reaction and adaptation of the real players. We have chosen the BDI architecture to model these virtual players, since its paradigm is based on folk psychology; hence, its core concepts easily map the language that people use to describe their reasoning and actions in everyday life. ViP-JogoMan is a computer-based game, in which people play via Web, players can be in different places and it does not have a hard constraint regarding the minimum number of real players. Our aim in this paper is to present some test results obtained with both prototypes, as well as to present a preliminary discussion on how the insertion of virtual players has affected the game results.Role-Playing Games, Multi-Agent Based Simulation, Natural Resources, Virtual Players

Linfadenite caseosa ou pseudotuberculose em pequenos ruminantes

Corynebacterium pseudotuberculosis é o agente etiológico da linfadenite caseo- sa, uma doença comum dos pequenos ruminantes em todo o mundo que causa pro- cessos piogranulomatosos crónicos em diferentes espécies de animais de produção (Motta et al., 2010). É primariamente uma infeção dos linfonodos periféricos, mas com o tempo pode envolver linfonodos viscerais e órgãos internos. Quando estabe- lecida a doença é de difícil erradicação pois a terapêutica não é efetiva, assim como, a deteção dos animais infetados.info:eu-repo/semantics/publishedVersio

Paratuberculose caprina: Seroprevalência de Mycobacterium avium subsp. paratuberculosis (Map) em caprinos no nordeste de Portugal e principais fatores associados: resultados preliminares

A paratuberculose apresenta elevada seroprevalência em caprinos no nordeste de Portugal. Foi efectuado um estudo epidemiológico em 95 explorações caprinas do nordeste de Portugal para a deteção de anticorpos contra Mycobacterium avium subsp. Paratuberculosis usando um ensaio imunoenzimático comercial (kit ELISA). Através da realização de inquéritos nas explorações estudaram-se os principais factores de risco presentes nas explorações.info:eu-repo/semantics/publishedVersio

Paratuberculose em pequenos ruminantes

A paratuberculose, ou doença de Johne é uma doença infeciosa causada por My- cobacterium avium subespécie paratuberculosis (Map). Afeta principalmente os rumi- nantes, originando uma enterite crónica granulomatosa e fatal. As probabilidades de cura do animal são escassas, o custo dos fármacos é elevado, superando na espécie ovina e caprina o valor do animal.info:eu-repo/semantics/publishedVersio

(Virtual) Agents for running electricity markets

This paper describes a multi-agent based simulation (MABS) framework to construct an artificial electric power market populated with learning agents. The artificial market, named TEMMAS (The Electricity Market Multi-Agent Simulator), explores the integration of two design constructs: (i) the specification of the environmental physical market properties and (ii) the specification of the decision-making (deliberative) and reactive agents. TEMMAS is materialized in an experimental setup involving distinct power generator companies that operate in the market and search for the trading strategies that best exploit their generating units' resources. The experimental results show a coherent market behavior that emerges from the overall simulated environment