Cesar Augusto Tacla

• Dr.
• Professor (Full) at Federal University of Technology of Paraná

Task delegation in multi-agent systems (MASs) is crucial for ensuring efficient collaboration among agents with different capabilities and skills. Traditional delegation models rely on social mechanisms such as trust and reputation to evaluate potential partners. While these approaches are effective in selecting competent agents, they often lack tr...

Este artigo destaca a importância das abordagens multiagentes na melhoria da resiliência e na rápida restauração do fornecimento de energia elétrica em cenários de eventos climáticos adversos. Utilizando dados reais da Companhia Paranaense de energia (COPEL), o estudo apresenta simulações, considerando geolocalização, afinidades e sobrecarga das eq...

This work presents an approach for distributed and contextualized reasoning in multi-agent systems, considering environments in which agents may have incomplete, uncertain and inconsistent knowledge. Knowledge is represented by defeasible logic with mapping rules, which model the capability of agents to acquire knowledge from other agents during re...

Human-aware Artificial Intelligent systems are goal-directed autonomous systems that are capable of interacting, collaborating, and teaming with humans. Some relevant tasks of these systems are recognizing human’s desires and intentions and exhibiting explicable behavior, giving cogent explanations on demand and engendering trust. This article tack...

As agent-based systems have been growing, more and more the general public has access to them and is influenced by decisions taken by these systems. This increases the necessity for such systems to be capable of explaining themselves to a user. The Beliefs-Desires-Intentions (BDI) is a commonly used agent model that has an two-phase internal goal s...

Existem casos em que um sistema deve atuar de forma autônoma. Um exemplo é realizar uma exploração em um cenário de acidente ou catástrofe natural para resgatar as vítimas. Uma das áreas que trata de sistemas autônomos é nomeada de Multiagente. Por diversas razões, pode ser necessário que o sistema gere explicações sobre suas ações. Por exemplo, po...

This work presents an approach for distributed and contextualized reasoning in multi-agent systems, considering environments in which agents may have incomplete, uncertain and inconsistent knowledge. Knowledge is represented by defeasible logic with mapping rules, which model the capability of agents to acquire knowledge from other agents during re...

The Bipolar Argumentation Framework approach is an extension of the Abstract Argumentation Framework. A Bipolar Argumentation Framework considers a support interaction between arguments, besides the attack interaction. As in the Abstract Argumentation Framework, some researches consider that arguments have a degree of uncertainty, which impacts on...

In the industrial sector, outlier detection makes it possible to quickly identify equipment failures. The evolution of Industry 4.0 is bringing challenges previously uncommon in the area. The large number of data constantly generated represents a processing challenge and can lead to the identification of a large number of outliers simultaneously. T...

Explainable Artificial Intelligence systems, including intelligent agents, are expected to explain their internal decisions, behaviors and reasoning that produce their choices to the humans (or to other systems) with which they interact. Given this context, the aim of this article is to introduce a practical reasoning agent framework that supports...

In cooperative environments is common that agents delegate tasks to each other to achieve their goals since an agent may not have the capabilities or resources to achieve its objectives alone. However, to select good partners, the agent needs to deal with information about the abilities, experience, and goals of their partners. In this situation, t...

Human-aware Artificial Intelligent systems are goal directed autonomous systems that are capable of interacting, collaborating, and teaming with humans. Activity reasoning is a formal reasoning approach that aims to provide common sense reasoning capabilities to these interactive and intelligent systems. This reasoning can be done by considering ev...

Algoritmos de aprendizado de caminhos ótimos estão presentes em diversos cenários. Diante disso, o LRTA* (learning real time A*) surge como uma opção que concilia planejamento e ação. O presente artigo estuda como a variação da quantidade de agentes impacta nas distâncias percorridas por eles para encontrar o caminho ótimo utilizando o LRTA* em amb...

Em um sistema multi-agente (SMA), é muito comum que os agentes deleguem tarefas uns aos outros. Contudo, devido à subjetividade das informações utilizadas pelos agentes durante o processo de tomada de decisão, um agente pode acabar delegando uma tarefa a um parceiro não confiável. Neste trabalho, apresentamos uma abordagem de cálculo de confiança b...

Argumentation-based persuasive negotiation is a form of negotiation dialogue in which agents, with different interests and goals, exchange proposals that are supported by rhetorical arguments such as threats, rewards, or appeals. Besides rhetorical arguments, additional kinds of illocutions may also be exchanged during the dialogue, for instance, a...

Este artigo apresenta o projeto RobotFun e seus objetivos: i) permitir que os estudantes do Grupo PET realizem atividades de pesquisa, ensino e extensão sob um único projeto, e ii) ser um meio de atrair estudantes para os cursos de engenharia de computação, ciência da computação e afins, e amenizar a evasão de calouros desses cursos. O grupo desenv...

In this study, we tackled the problem of distributed reasoning in environments in which agents may have incomplete and inconsistent knowledge. Conflicts between agents are resolved through defeasible argumentation-based semantics with a preference function. Support for dynamic environments, where agents constantly enter and leave the system, was ac...

The aim of this article is to propose a model for the measurement of the strength of rhetorical arguments (i.e., threats, rewards, and appeals), which are used in persuasive negotiation dialogues when a proponent agent tries to convince his opponent to accept a proposal. Related articles propose a calculation based on the components of the rhetoric...

During the first step of practical reasoning, i.e. deliberation or goals selection, an intelligent agent generates a set of pursuable goals and then selects which of them he commits to achieve. Explainable Artificial Intelligence (XAI) systems, including intelligent agents, must be able to explain their internal decisions. In the context of goals s...

In this paper, we extend previous work on distributed reasoning using Contextual Defeasible Logic (CDL), which enables decentralised distributed reasoning based on a distributed knowledge base, such that the knowledge from different knowledge bases may conflict with each other. However, there are many use case scenarios that are not possible to rep...

By considering rational agents, we focus on the problem of selecting goals out of a set of incompatible ones. We consider three forms of incompatibility introduced by Castelfranchi and Paglieri, namely the terminal, the instrumental (or based on resources), and the superfluity. We represent the agent's plans by means of structured arguments whose p...

argumentation approaches consider that arguments have a degree of uncertainty, which impacts on the degree of uncertainty of the extensions obtained from a abstract argumentation framework (AAF) under a semantics. In these approaches, both the uncertainty of the arguments and of the extensions are modeled by means of precise probability values. How...

During the first step of practical reasoning, i.e. deliberation or goals selection, an intelligent agent generates a set of pursuable goals and then selects which of them he commits to achieve. Explainable Artificial Intelligence (XAI) systems, including intelligent agents, must be able to explain their internal decisions. In the context of goals s...

Explainable Artificial Intelligence (XAI) systems, including intelligent agents, must be able to explain their internal decisions, behaviours and reasoning that produce their choices to the humans (or other systems) with which they interact. In this paper, we focus on how an extended model of BDI (Beliefs-Desires-Intentions) agents can be able to g...

An intelligent agent may in general pursue multiple procedural goals simultaneously, which may lead to arise some conflicts (incompatibilities) among them. In this paper, we focus on the incompatibilities that emerge due to resources limitations. Thus, the contribution of this article is twofold. On one hand, we give an algorithm for identifying re...

During the first step of practical reasoning, i.e. deliberation, an intelligent agent generates a set of pursuable goals and then selects which of them he commits to achieve. An intelligent agent may in general generate multiple pursuable goals, which may be incompatible among them. In this paper, we focus on the definition, identification and reso...

O problema de Agregação de Julgamento tem como objetivo unir o julgamento de vários indivíduos em um único conjunto para se chegar a um acordo do grupo. Utilizando a plataforma JaCaMo, uma ferramenta de três camadas, ambiente, sistema multiagente, e organizacional, este trabalho descreve a especificação do modelo de agregação de julgamento de Camin...

O objetivo deste artigo é propor uma arquitetura e discutir o design e implementação de um simulador de agentes baseados em Processamento de Objetivos Baseado em Crenças (BBGP). Uma implementação do modelo poderia ser empregada em estudos do modelo conceitual BBGP além de tornar mais simples a análise e explicação do processo de raciocínio do agent...

In multi-agent systems (MAS), computational reputation models have been adopted as an important solution in order to ensure security and efficiency. The evaluation mechanisms, offered by these models, can be used to punish inappropriate behaviors of agents and improve the partner selection process in uncertain situations. However, as the reputation...

Threats are used in persuasive negotiation dialogues when a proponent agent tries to persuade an opponent of him to accept a proposal. Depending on the information the proponent has modeled about his opponent(s), he may generate more than one threat, in which case he has to evaluate them in order to select the most adequate to be sent. One way to e...

Computational Argumentation has been applied successfully over legal disputes, especialy in consuetudinary law (case-based). In order to extend this approach to other legal systems-such as positive law-it is necessary to distinguish the backup of arguments based on past cases from the guarantees of the arguments based on positive laws. In this pape...

Argumentação computacional tem sido empregada com sucesso em problemas de disputas judiciais, principalmente no direito consuetudinário (baseado em precedentes). Para estender essa abordagem a outros sistemas -como o direito positivo- é necessário distinguir o respaldo dos argumentos baseados em precedentes das garantias dos argumentos baseados em...

Rhetorical arguments are used in negotiation dialogues when a proponent agent tries to persuade his opponent to accept a proposal more readily. When more than one argument is generated, the proponent must compare them in order to select the most adequate for his interests. A way of comparing them is by means of their strength values. Related articl...

By considering rational agents, we focus on the problem of selecting goals out of a set of incompatible ones. We consider three forms of incompatibility introduced by Castelfranchi and Paglieri, namely the terminal, the instrumental (or based on resources), and the superfluity. We represent the agent's plans by means of structured arguments whose p...

argumentation approaches consider that arguments have a degree of uncertainty, which impacts on the degree of uncertainty of the extensions obtained from a abstract argumentation framework (AAF) under a semantics. In these approaches, both the uncertainty of the arguments and of the extensions are modeled by means of precise probability values. How...

A elaboração de políticas públicas, muitas vezes, provém de um processo participativo. Assim, este projeto propõe o desenvolvimento de uma arquitetura que permita a usuários, tanto cidadãos quanto gestores, construir seus próprios índices ambientais, monitorá-los em tempo real e publicá-los em formato aberto. Pretende-se conceder aos cidadãos a pos...

This paper presents a model of dialogue to support the common-knowledge formation in a group of agents which is based on the exchange of arguments supporting or rejecting an issue under discussion and other arguments during the dialogue. In the model, the agents play two roles: argumentative and mediator. Argumentative agents are responsible for bu...

Organizations have been increasingly relying on software development to manage their business, making it an essential activity. Companies have been using collaborative development environments to speed up their deliveries, resulting in projects tending to be produced by developers from different parts of the world with different cultures. In this c...

In an argumentative dialogue, agents exchange arguments to approve or disapprove a decision alternative. The problem arises when a group of agents with incomplete information needs to reach consensus on the decision. This study proposes a framework for decision-making where the argumentative agents can build the necessary common knowledge to make a...

In this work, we present an argumentation-based formalization for supporting the process of formation of intentions in practical agents. This is based on the belief-based goal processing model proposed by Castelfranchi and Paglieri, which is a more expressive and refined model than the BDI (Beliefs-Desires-Intentions) model. We focus on the progres...

During the first step of practical reasoning, i.e. deliberation, an intelligent agent generates a set of pursuable goals and then selects which of them he commits to achieve. An intelligent agent may in general generate multiple pursuable goals, which may be incompatible among them. In this paper, we focus on the definition, identification and reso...

Abstract: Several projects have been developed with the aim to represent indicators for the environmental pollution following definitions of ISO 37120. The objective of these standards is to allow the comparison of indicators in different domains regarding the Smart Cities concepts. This paper proposes new constructs that extend ontologies derived...

A investigação no campo de jogos sérios está atraindo grande atenção da comunidade acadêmica. A lógica deôntica e sistemas normativos possuem uma grande importância no desenvolvimento de jogos sérios. Agentes normativos englobam representações computacionais das relações sociais, estruturais e deônticas no contexto de organização em sistemas multia...

One of the challenges of rhetorical arguments is how to evaluate which argument is more suitable to send to an opponent in a specific situation. This work presents a fuzzy-based decision-making mechanism for agents to appropriately choose one argument among different rhetorical arguments. Some scenarios were developed and the results yielded by our...

An intelligent agent may in general pursue multiple procedural goals simultaneously, which may lead to arise some conflicts (incompatibilities) among them. In this paper, we focus on the incompatibilities that emerge due to resources limitations. Thus, the contribution of this article is twofold. On one hand, we give an algorithm for identifying re...

An intelligent agent may in general pursue multiple goals at the same time, which leads to arise some conflict among them. In this paper, we focus on these conflicts or incompatibilities among goals. Our approach is based on the model of Castelfranchi and Paglieri, in which, three forms of incompatibility and the criteria for selection of goals are...

A portfolio problem is about selecting one or several out of a set of possible items, considering some constraints, and where outcomes are determined by a form of aggregating the properties of the items selected. In this paper, we aim to study the use of abstract argumentation theory for a simplified version of the portfolio selection problem, wher...

Rewards are rhetorical arguments that have a positive nature since they use the argument that something positive will happen to the opponent if he accepts to do the proponent requirement. During a persuasive negotiation more than one reward can be generated and the proponent has to choose one to send to his opponent. Since one measure that could he...

Threats make part of the set of rhetorical arguments, which are used in negotiation dialogues when a proponent agent tries to persuade his opponent to accept a proposal more readily. When more than one threat is generated, the proponent must evaluate each and select the most adequate. One way of evaluation is calculating the strength of threats, si...

Persuasive negotiation involves negotiating using rhetorical arguments (such as threats, rewards, and appeals), which act as persuasive elements that aim to force or convince an opponent to accept a given proposal. In the case of rewards, these have a positive nature as they use the argument that something positive will happen to the opponent if he...

Diversos sistemas de argumentação aplicados na tomada de decisão em sistemas multiagentes foram propostos. No entanto, pouca atenção foi dada aos casos onde a decisão deve ser obtida de forma consensual. Apresentamos um protocolo para diálogos baseado em argumentação para apoio na tomada de decisão consensual onde o diálogo é dinâmico, não havendo...

Noctua is a web tool to assist in Knowledge Acquisition and Collaborative Knowledge Construction processes. Noctua has an innovation: a Virtual Catalyst designed to facilitate the task of eliciting and validating knowledge. The Virtual Catalyst queries participants, proposing new knowledge, seeking confirmation to the knowledge already elicited, an...

The difficulty of students in learning logic and programming languages leads the research of technological solutions to assist in the teaching-learning process. Among these solutions, two common approaches are robotics and graphical-based programming languages. Researches indicate that these tools can aid learners to think systematically and develo...

Este trabalho apresenta a aplicação de uma metodologia de avaliação de utilidade de opiniões com o objetivo de identificar quais características exercem maior influência na quantidade de votos de utilidade: básicas (ex. nota sobre o produto e/ou serviço, data da publicação), textuais (ex. tamanho das palavras, parágrafos) e semântica (ex. o signifi...

Software development is a collaborative activity, dependent on technology and performed by groups of people. The software technology involved is an important factor, since it provides the necessary tools for the development of the work. This paper presents a collaborative virtual workspace that follows the code development, comparing it with the mo...

Knowledge discovery is the process of discovering useful knowledge in a broad range of sources, such as relational databases, images, or texts. Dialogues are generated by interaction between people using natural language and can be used as a source of information. Once discovered, knowledge needs to be represented, and there are several approaches...

Data-Oriented Belief Revision (DBR) is a relatively recent approach that claims the difference between pieces of information gathered and stored by agent (data) and information revised and considered reliable (beliefs). Data structure proposed in DBR can also be used to implement the structure of an argument. It’s worth noting that this approach ca...

Document source code is seen as a boring time consuming task by several developers. However, a welldocumented source code, allow developers to have a better visibility into what was and is being developed, helping, for example, the reuse of the code. This study presents a semi-automatic method for documentation of source code from the existing arti...

This paper presents the FOLKUS-SD a module of CSCW-SD, intend to build Folksonomies from source codes. The CSCW-SD is an architecture to integrate tools in a development environment through a Multi-Agent System. The Folksonomies are built using dynamic data collected during codification. The Folksonomies' entities are represented by the module as:...

Há muito interesse na construção de ontologias, porém, há poucos trabalhos que apontam para uma utilização de ontologias em larga escala. Algumas das razões para isso são o tempo, custo e recursos associados ao desenvolvimento. Com o objetivo de reduzir estes esforços, métodos de aprendizagem de ontologias têm sido desenvolvidos. Para isso, é neces...

Recent researches have shown that approaches based on the multiagent paradigm and market mechanisms like auctions are efficient in solving planning problems in supply chains (SC), which is characterised as a network of producers and consumers that enables gathering of raw materials, their transformation into products, and their distribution through...

There is much interest in building ontologies, however, there are few works pointing to a large-scale use of ontologies. Some reasons for this are time, cost, and resources associated with the development. With the goal of reducing such efforts, ontology learning methods have been developed. Therefore, it is necessary to automate the process of acq...

This paper presents a method for assessing whether folksonomies are shared conceptualizations useful for conceptual modeling. The proposed method extracts domain knowledge from tagging data of social applications starting with a description of the domain. The result is a folksonomy whose utility can be assessed in collaborative conceptual modeling...

The Abstract Computational Model of Awareness for Community Identification (AMACI) is based on the contents of resources created or used by users, which allows noticing others that perform or have performed activities in similar contexts, thereby identifying potential communities and teams. The model was evaluated through experiments using data fro...

We have been researching in CSCW for small teams for the last years. As we presented in previous works, small software development teams have special needs and requirements that must be taken into account when designing tools for supporting cooperation of their participants. We have already proposed the architecture of a system (called CSCW-SD) to...

Mecanismos de mercado, como leilões, combinados com abordagens baseadas em sistemas multiagentes (MAS) têm sido aplicados com sucesso na busca de soluções factíveis em problemas de planejamento em cadeias de abastecimento. Uma cadeia de suprimento (SC)é caracterizada como uma rede de produtores e consumidores, que permite a coleta de matérias-prima...

This paper proposes a framework of the negotiation process for solving divergences in the collaborative ontology development. Such framework is obtained through the use of philosophical principles deriving from the theories of essence, identity, unity and dependence (preconized by the OntoClean methodology) as to justify part of the argumentation u...

The transportation planning of oil products in Brazil's multimodal network is a complex problem that involves several negotiations between decentralized entities in order to agree on the products to transfer, their amounts, and allocation of shared resources. Due to such complexity, a decision supporting tools that can help the decision makers is a...

This paper presents a comparative study among default implementations of Genetic Algorithm, Differential Evolution and Particle Swarm Optimization for load balancing, a specific case of the Generalized Assignment Problem (GAP). Differential Evolution was found the best algorithm, and it was further tested with harder GAP instances to determine its...

Looking to reduce the problem of knowledge acquisition bottleneck, this work takes on the hypothesis that the folksonomy induced from collaborative tagging data on the Web, based on parameters of authorship and motivation of categorization, can represent a shared conceptualization of a domain. Thus, it is expected that the use of such data can gene...

The present article describes an architecture proposed to identify the probable actions taken by an actor involved in a software development process. Such a process is a collaborative activity that can be associated to a context that comprises tasks and interactions for information exchange, targeting the manipulation of artifacts being developed....

This paper presents a new programming paradigm named Notification-Oriented Paradigm (NOP) and analyses the per-formance aspects of NOP programs by means of an experiment. NOP provides a new manner to conceive, structure, and execute software, which would allow better performance, causal-knowledge organization, and decoupling than standard solutions...

The transportation planning of oil products in Brazil's multimodal network is a complex problem that involves several negotiations between decentralized entities in order to agree on the products to transfer, their amounts, and allocation of shared resources. Due to such complexity, a decision supporting tools that can help the decision makers is a...

Resumo: Em cadeias de suprimento da indústria de petróleo, atender a demanda e manter um nível de estoque adequado para várias classes de derivados de petróleo é uma questão crucial. Basicamente, este tipo de cadeia é composta por vários elementos, como bases produtoras, bases consumidoras e terminais intermediários, os quais estão conectados por m...

During the software development cycle, artifacts (source-code, documentation, user manuals, etc.) are written, most of them, cooperatively. Each participant in a software development team plays a specific role, but may write an artifact cooperatively with participants playing different roles. In large and distributed teams the roles are well-define...

This paper presents a new programming paradigm named Notification-Oriented Paradigm (NOP) and analyses the performance aspects of NOP programs by means of an experiment. NOP provides a new manner to conceive, structure, and execute software, which would allow causal-knowledge organization and decoupling better than standard solutions based upon cur...

This work purposes to use data of collaborative tagging as shared conceptualization that can be useful to build conceptual models. The hypothesis assumes that the folksonomy induced from the collaborative tagging's data based on parameters of authorship and motivation of categorization can represent a shared conceptualization of a domain. Thus, it...

Software developers often face the task of documenting source code. For many of them, documenting code development is a boring task. However, source code documentation is an important task, especially when dealing with groups of developers. An updated documentation allows group members to have greater visibility on what has been and is being develo...

Divergences in conceptual modeling choices are inherent to the collaborative ontology development. Such divergences have been typically solved through some process of negotiation among the participants of the development process. When negotiating, the participants argue to defend their ideas based on their past experiences. We propose to support an...

In supply chains of petroleum industry, maintaining a proper inventory level for multiple petroleum products is a crucial issue. Basically, this chain has several elements like producer bases, consumer bases and terminals that are linked by means of a multi-modal transport network. These elements must cooperate to achieve the global goal of the sys...

Recent researches show that approaches based on auctions and multi-agent systems are efficient on the resolution of planning problems in supply chains. This paper proposes a multi-agent system that uses combinatorial auctions to solve the oil derivative transport planning problem in multimodal networks in order to find a more efficient solution tha...

Building application domain models is a time-consuming activity in software engineering. In small teams, it is an activity that involves almost all participants, including developers and domain experts. In our approach, we support the knowledge engineering activity by reusing tagging done by team participants when they search information on the Web...

Noctua is a tool to assist the Knowledge Acquisition and Collaborative Knowledge Construction processes. Noctua contains a virtual catalyst designed to facilitate the task of eliciting and validating knowledge. The virtual catalyst queries collaborators, proposing new knowledge, seeking confirmation to the knowledge already elicited, and showing co...

Este artigo apresenta uma revisão dos conceitos relacionados ao Paradigma Orientado a Notificações (PON) e uma comparação, qualitativa e quantitativa, de duas versões de uma mesma aplicação. A primeira desenvolvida de acordo com os princípios do Paradigma Orientado a Objetos (POO) e a segunda inclusive de acordo com os princípios do PON. O PON se a...

In this paper, we discuss the construction of dialogs for Personal Assistant Agents that are in charge of the interface between users and a Multi-Agent System. Such a system aims at providing support for small teams developing software collaboratively. Small teams have specific needs such as the integration of free or open-source tools or the suppo...

The identification of nonlinear systems with artificial neural networks models has been successfully used in many applications. Most processes in industry are characterized by nonlinear and time-varying behavior. In this context, the identification of mathematical models for nonlinear systems is vital in many fields of engineering. The Radial Basis...

This work presents and evaluates the performance of a simulation model based on multiagent system technology in order to support logistic decisions in a harbor from oil supply chain. The main decisions are concerned to pier allocation, oil discharge, storage tanks management and refinery supply by a pipeline. The real elements as ships, piers, pipe...

In supply chains of the petroleum industry, maintaining a balance between production and consumption of petroleum derivatives is a crucial issue. Basically, this kind of chain has several elements like producer bases, consumer bases, intermediary terminals that are linked by a transport network. These elements should cooperate to reach the global b...

This paper describes a method to partially align ontologies in dialogs of agents which use different ontologies. The method aims at aligning in execution time only the concepts necessary to the agents fulfill the current dialog. Thus, reducing the number of concepts to be searched in the target ontology is a very important requirement for agents' m...