A resolution-based E-connected calculus

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2019.Neste trabalho, apresentamos um cálculo para raciocinar sobre E-conexões, as quais provêem um método computacionalmente robusto para combinar Abstract Description Systems (ADSs) arbitrários. ADSs, introduzidos por Baader et al, são uma generalização de várias lógicas, tais como temporais, espaciais, epistêmicas, lógicas descritivas e modais. Provemos um cálculo baseado em resolução para lidar com conexões, assumindo que o problema de satifatibilidade global das lógicas componentes é decidível. Isto nos permite focar em raciocinar apenas sobre as restrições impostas pelas E-conexões, deixando o raciocínio específico de cada domínio para as lógicas componentes. Um dos passos mais importantes necessários para alcançar isto é a devida separação dos elementos sintáticos relacionados às diferentes componentes, através de uma forma normal proposta. Assim, provemos o conjunto completo de regras de transformação, apresentando provas para a terminação e preservação de satisfatibilidade desta transformação. Este trabalho apresenta as provas de correção, completude e terminação para o cálculo proposto. Também disponibilizamos uma implementação prototípica, baseada no provador KSP. Discutimos os resultados da avaliação e sugerimos algumas modificações que podem ser feitas para melhorar a performance, abrindo caminho para o desenvolvimento de uma futura implementação tanto modular quanto eficiente.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).We introduce a calculus to reason about E-connections, which provide a computationally ro- bust method to combine arbitrary Abstract Description Systems (ADSs). ADSs, introduced by Baader et al, are a generalization of various logics such as temporal, spatial, epistemic descrip- tion and modal logics in general. In this work, we restrict the logics to be combined to normal modal logics. We provide a resolution-based calculus to deal with connections, assuming that the global satisfiability problems of the component logics are decidable. This allows us to focus on reasoning only about the restrictions imposed by the E-connections, leaving domain-specific reasoning to the component logic. One of the most important steps required to achieve this is the proper separation of syn- tactical elements related to different components via a proposed normal form. Therefore, we provide the full set of transformation rules, presenting proofs for termination and preservation of satisfiability of this transformation. This work presents the correctness, completeness and termination proofs for the proposed calculus. We also make available a proof-of-concept implementation, based on the KSP prover. We discuss the results of the evaluation and suggest some modifications that can be made to improve performance, paving the way for the development of a future modular and efficient implementation

Some aspects of the homogeneous formalism in Field Theory and gauge invariance

We propose a suitable formulation of the Hamiltonian formalism for Field Theory in terms of Hamiltonian connections and multisymplectic forms where a composite fibered bundle, involving a line bundle, plays the role of an extended configuration bundle. This new approach can be interpreted as a suitable generalization to Field Theory of the homogeneous formalism for Hamiltonian Mechanics. As an example of application, we obtain the expression of a formal energy for a parametrized version of the Hilbert--Einstein Lagrangian and we show that this quantity is conserved.Comment: 9 pages, slightly revised, to appear in Proc. Winter School "Geometry and Physics", Srni (CZ) 200

Digital Ecosystems: Ecosystem-Oriented Architectures

We view Digital Ecosystems to be the digital counterparts of biological ecosystems. Here, we are concerned with the creation of these Digital Ecosystems, exploiting the self-organising properties of biological ecosystems to evolve high-level software applications. Therefore, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems, where the optimisation works at two levels: a first optimisation, migration of agents which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. The Digital Ecosystem was then measured experimentally through simulations, with measures originating from theoretical ecology, evaluating its likeness to biological ecosystems. This included its responsiveness to requests for applications from the user base, as a measure of the ecological succession (ecosystem maturity). Overall, we have advanced the understanding of Digital Ecosystems, creating Ecosystem-Oriented Architectures where the word ecosystem is more than just a metaphor.Comment: 39 pages, 26 figures, journa

Computational physics of the mind

In the XIX century and earlier such physicists as Newton, Mayer, Hooke, Helmholtz and Mach were actively engaged in the research on psychophysics, trying to relate psychological sensations to intensities of physical stimuli. Computational physics allows to simulate complex neural processes giving a chance to answer not only the original psychophysical questions but also to create models of mind. In this paper several approaches relevant to modeling of mind are outlined. Since direct modeling of the brain functions is rather limited due to the complexity of such models a number of approximations is introduced. The path from the brain, or computational neurosciences, to the mind, or cognitive sciences, is sketched, with emphasis on higher cognitive functions such as memory and consciousness. No fundamental problems in understanding of the mind seem to arise. From computational point of view realistic models require massively parallel architectures

Addressing performance requirements in the FDT-based design of distributed systems

The development of distributed systems is generally regarded as a complex and costly task, and for this reason formal description techniques such as LOTOS and ESTELLE (both standardized by the ISO) are increasingly used in this process. Our experience is that LOTOS can be exploited at many stages on the design trajectory, from requirements specification to implementation, but that the language elements do not allow direct formalization of performance requirements. To avoid duplication of effort by using two formalisms with distinct approaches, we propose a design method that incorporates performance constraints in an heuristic but effective manner

An architecture-based dependability modeling framework using AADL

For efficiency reasons, the software system designers' will is to use an integrated set of methods and tools to describe specifications and designs, and also to perform analyses such as dependability, schedulability and performance. AADL (Architecture Analysis and Design Language) has proved to be efficient for software architecture modeling. In addition, AADL was designed to accommodate several types of analyses. This paper presents an iterative dependency-driven approach for dependability modeling using AADL. It is illustrated on a small example. This approach is part of a complete framework that allows the generation of dependability analysis and evaluation models from AADL models to support the analysis of software and system architectures, in critical application domains

Contextuality-by-Default: A Brief Overview of Ideas, Concepts, and Terminology

This paper is a brief overview of the concepts involved in measuring the degree of contextuality and detecting contextuality in systems of binary measurements of a finite number of objects. We discuss and clarify the main concepts and terminology of the theory called "contextuality-by-default," and then discuss a possible generalization of the theory from binary to arbitrary measurements.Comment: Lecture Notes in Computer Science 9535 (with the corrected list of authors) (2016

Development of a client interface for a methodology independent object-oriented CASE tool : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University

The overall aim of the research presented in this thesis is the development of a prototype CASE Tool user interface that supports the use of arbitrary methodology notations for the construction of small-scale diagrams. This research is part of the larger CASE Tool project, MOOT (Massey's Object Oriented Tool). MOOT is a meta-system with a client-server architecture that provides a framework within which the semantics and syntax of methodologies can be described. The CASE Tool user interface is implemented in Java so it is as portable as possible and has a consistent look and feel. It has been designed as a client to the rest of the MOOT system (which acts as a server). A communications protocol has been designed to support the interaction between the CASE Tool client and a MOOT server. The user interface design of MOOT must support all possible graphical notations. No assumptions about the types of notations that a software engineer may use can be made. MOOT therefore provides a specification language called NDL for the definition of a methodology's syntax. Hence, the MOOT CASE Tool client described in this thesis is a shell that is parameterised by NDL specifications. The flexibility provided by such a high level of abstraction presents significant challenges in terms of designing effective human-computer interaction mechanisms for the MOOT user interface. Functional and non-functional requirements of the client user interface have been identified and applied during the construction of the prototype. A notation specification that defines the syntax for Coad and Yourdon OOA/OOD has been written in NDL and used as a test case. The thesis includes the iterative evaluation and extension of NDL resulting from the prototype development. The prototype has shown that the current approach to NDL is efficacious, and that the syntax and semantics of a methodology description can successfully be separated. The developed prototype has shown that it is possible to build a simple, non-intrusive, and efficient, yet flexible, useable, and helpful interface for meta-CASE tools. The development of the CASE Tool client, through its generic, methodology independent design, has provided a pilot with which future ideas may be explored