Issues in the Probability Elicitation Process of Expert-Based Bayesian Networks

A major challenge in constructing a Bayesian network (BN) is defining the node probability tables (NPT), which can be learned from data or elicited from domain experts. In practice, it is common not to have enough data for learning, and elicitation from experts is the only option. However, the complexity of defining NPT grows exponentially, making their elicitation process costly and error-prone. In this research, we conducted an exploratory study through a literature review that identified the main issues related to the task of probability elicitation and solutions to construct large-scale NPT while reducing the exposure to these issues. In this chapter, we present in detail three semiautomatic methods that reduce the burden for experts. We discuss the benefits and drawbacks of these methods, and present directions on how to improve them

Continuous Learning of the Structure of Bayesian Networks: A Mapping Study

Bayesian networks can be built based on knowledge, data, or both. Independent of the source of information used to build the model, inaccuracies might occur or the application domain might change. Therefore, there is a need to continuously improve the model during its usage. As new data are collected, algorithms to continuously incorporate the updated knowledge can play an essential role in this process. In regard to the continuous learning of the Bayesian network’s structure, the current solutions are based on its structural refinement or adaptation. Recent researchers aim to reduce complexity and memory usage, allowing to solve complex and large-scale practical problems. This study aims to identify and evaluate solutions for the continuous learning of the Bayesian network’s structures, as well as to outline related future research directions. Our attention remains on the structures because the accurate parameters are completely useless if the structure is not representative

Component-based infrastructure for software development with support for unanticipated dynamic evolution.

As atividades relacionadas à evolução têm sido apontadas como fatores de grande impacto sobre o custo e o tempo inerentes ao processo de engenharia de sistemas de software. O impacto causado por tais atividades de evolução é maior quando as mudanças de requisitos a serem contempladas em um software existente não são previstas, ou antecipadas, durante o projeto inicial do sistema. Este tipo de evolução torna-se ainda mais complexo em determinados domínios de aplicação, nos quais, por razões financeiras ou de segurança, a evolução deve ser realizada dinamicamente, ou seja, sem que a execução do software seja interrompida. Neste trabalho apresenta-se uma infra-estrutura para o desenvolvimento de software com suporte à evolução dinâmica não antecipada. Mais especificamente, introduz-se um modelo de composição de componentes, arcabouços e um conjunto de ferramentas que permitem o desenvolvimento de software com suporte a mudanças não previstas nos seus requisitos iniciais. Apresenta-se um arcabouço genérico para a implementação da especificação de componentes, assim como, a implementação deste arcabouço nas linguagens Java, Python, C++ e C Sharp, e a extensão deste arcabouço para a construção de aplicações corporativas. Propõe-se também um modelo para análise de desempenho de aplicações desenvolvidas utilizando a infra-estrutura. As ferramentas desenvolvidas para o suporte ao desenvolvimento de componentes e composição, análise de desempenho e execução de aplicações também são descritas. Apresenta-se também a utilização do método formal Alloy na definição de um mecanismo que possibilita que o desenvolvedor verifique se um dado cenário de evolução não antecipada satisfaz a corretude da especificação formal do sistema. Para guiar o desenvolvedor na utilização da infra-estrutura, descreve-se um processo de desenvolvimento de software com suporte à evolução dinâmica não antecipada. Por fim, a validação do trabalho foi realizada através do desenvolvimento de várias aplicações nos contextos de computação pervasiva, sistemas multi-agentes e comunidades virtuais móveis.Software evolution has been pointed out as an activity of great impact on the total cost and time of the software engineering process. Such an impact is more significative when requirement changes have not been predicted, or anticipated, during the initial software design. Managing this kind of evolution is more complex in some application domains in which software changes must be performed without stopping the system execution, due to financial or safety reasons. This work presents an infrastructure for developing software with support to dynamic unanticipated evolution. More specifically, we propose a component model,software frameworks and a set of tools that allow developing software with support to unpredicted changes. It is presenteda generic framework to implement the component model specification as well as its implementation in Java, Python, C++ and C Sharp. Also, an extension of the generic framework for developing enterprise applications is presented. Also, we introduce a model to analyze the performance of applications developed with the infrastructure. Tools constructed to support the development of components and the composition, performance analisys, and execution of applications are also described. We also present the application of the Alloy formal method to specify a mechanism to allow developers to verify if a given unanticipated evolution scenario will impact the system specification correctness. To guide developers in using the proposed infrastructure, we present a process to develop software with support to dynamic unanticipated evolution. Finally,several applications of the proposed infrastructure in the context of pervasive computing, multi-agent systems and mobile virtual communities are presented.CNPqCape

A Model-Based Approach to Support Validation of Medical Cyber-Physical Systems

Medical Cyber-Physical Systems (MCPS) are context-aware, life-critical systems with patient safety as the main concern, demanding rigorous processes for validation to guarantee user requirement compliance and specification-oriented correctness. In this article, we propose a model-based approach for early validation of MCPS, focusing on promoting reusability and productivity. It enables system developers to build MCPS formal models based on a library of patient and medical device models, and simulate the MCPS to identify undesirable behaviors at design time. Our approach has been applied to three different clinical scenarios to evaluate its reusability potential for different contexts. We have also validated our approach through an empirical evaluation with developers to assess productivity and reusability. Finally, our models have been formally verified considering functional and safety requirements and model coverage

Specifying laws in open multi-agent systems

Abstract. Laws have been used to deal with theoretical and practical issues regarding notions of openness and unpredictably of open multiagent systems. In order to achieve a higher degree of predictability and confidence, practical applications of distributed agents need to describe the interaction structure of the system, and this interaction structure must be regulated. Governing agent interactions can lead to higher degree of system trust. This paper uses the notion of interaction laws as abstraction to regulate agents ’ interaction. In this paper, we introduce a conceptual model for developing laws in open multi-agent systems. This model is composed of static, dynamic and formal definitions. We also depict a declarative language used for supporting the conceptual model. Moreover, we show a software implementation that allows the enforcement of laws through the interception of agents ’ interaction. Finally, the conceptual model is applied in a case study in the domain of flight ticket trading.

A Comparative Analysis of Agile Teamwork Quality Measurement Models

Multiple models (or instruments) for measuring Teamwork Quality (TWQ) for Agile Software Development can be found in the literature. Regardless, such models have different constructs and measures, with no empirical evidence for comparing them. This study analyzed two agile TWQ models, resulting in equivalent results. We mapped the models\u27 variables given their definitions.We then collected data using both a Bayesian Network model, namely the TWQ-BN model, and Structural Equation Modeling, namely the TWQ-SEM model. We interviewed 162 team members from two software development companies. We analyzed the data using the Bland-Altman method. We obtained enough evidence to conclude that the results for Communication, Coordination, Cohesion and Mutual Support variables are not equivalent. On the other hand, we did not have enough evidence to claim that the models do not agree for measuring Effort and Balance of member contribution variables. The results of this study detail how two state-of-the-art agile TWQs compare in terms of their measures as well as potential research areas for further investigation

Additional file 1 of An admission control mechanism for dynamic QoS-enabled opportunistic routing protocols

Complete dataset of normality and inference tests of the performed experiments. The additional file presents the complete description of evaluated scenarios, the complete dataset of Student’s t test and the complete dataset of inference statistical tests

A Component Based Infrastructure to Develop Software Supporting Dynamic Unanticipated Evolution

Abstract. This paper presents a component based infrastructure for developing software supporting dynamic unanticipated software evolution. We propose a component model providing mechanisms for managing unpredicted software changes, even at runtime. A Java implementation of the proposed model is also presented. Moreover, a performance evaluation model and an Eclipse-based tool to support composition activities are described. Finally, a pervasive computing middleware application developed using the proposed infrastructure is presented. Resumo. Neste artigo apresenta-se uma infra-estrutura baseada em componentes para o desenvolvimento de software com suporte à evolução dinâmica não antecipada. Propõe-se um modelo de componentes que provê mecanismos para gerenciar alterações no software não previstas em projeto, inclusive em tempo de execução. Apresenta-se uma implementação em Java do modelo de componentes e um modelo analítico para avaliação de desempenho. Para dar suporte às atividades de desenvolvimento, propõe-se uma ferramenta baseada na plataforma Eclipse. Por fim, apresenta-se uma aplicação da infra-estrutura proposta para o desenvolvimento de um middleware para computação pervasiva. 1