36 research outputs found

    On Modelling Communication in Ubiquitous Computing Systems using Algebraic Higher Order Nets

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    Ubiquitous computing systems (UCSs) are designed to participate almostimperceptibly in everyday life. To ensure a solid operation, a UCS heavily depends on a reliable and efficient communication between its distributed computing components. Moreover components can join and leave the system at any time.In order to guarantee high quality systems, the use of models is inevitable especiallyat an early stage of the development process where models are the only possibilityto address a system which does not yet exist in reality. Petri nets and graph transformationsystems are established, theoretically well-founded concepts for modellingand analysing complex systems.This paper presents a formal approach for modelling core aspects of the communicationin UCSs by using Algebraic Higher Order Nets with Individual Tokens andgraph transformation. The approach is suitable to cover the different aspects ofcommunication and enables the analysis of specific properties. The approach and itssuitability are illustrated based on a running example. The feasibility of embeddingthe approach in a broader context of modelling is demonstrated in applying it to areal world system: the Living Place Hamburg

    Developing a design framework for communication systems

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    An Efficient Design Methodology for Complex Sequential Asynchronous Digital Circuits

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    Asynchronous digital logic as a design alternative offers a smaller circuit area and lower power consumption but suffers from increased complexity and difficulties related to logic hazards and elements synchronization. The presented work proposes a design methodology based on the speed-independent sequential logic theory, oriented toward asynchronous hardware implementation of complex multi-step algorithms. Targeting controller-centric devices that perform data-driven non-linear execution, the methodology offers a CSP language-based controller workflow description approach and the specification of a project implementation template supported by a two-stage design process. First, the CSP layer describes complex speed-independent controller behavior offering better scalability and maintainability than the STG model. Second, the component-oriented design template specifies functional elements\u27 structural organization and emphasizes the divide-and-conquer philosophy, streamlining large and complex devices\u27 design and maintenance. Finally, the implementation process is divided into two stages: a rapid development and functional verification stage and a synthesizable codebase stage. Additionally, a case study design of a split-transaction MESI cache coherency controller and its analysis are presented to validate the proposed methodology. The testing phase compares synthesized and routed gate-level asynchronous and synchronous implementations. For models synthesized to work with the same speed, the asynchronous circuit area is 20% smaller with lower power consumption at approximately 18% of the synchronous reference. The synchronous version synthesized for performance is 3.5 times faster, at the cost of a large increase in area and power usage. The results prove the methodology\u27s ability to deliver working complex asynchronous circuits competitive in the chip area and power characteristics

    Guide to Discrete Mathematics

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    Availability by Design:A Complementary Approach to Denial-of-Service

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    The New Trivium

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    Business Rules Integration on a Public Illumination Management System

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    Tese de mestrado, Engenharia Informática (Sistemas de Informação), Universidade de Lisboa, Faculdade de Ciências, 2021This work is based on the proposal of integrating Business Rules in a software product called SIIP, intended to serve the Public Illumination Division of Lisbon’s city council, which is a public organization. This application helps manage all types of requests related to the city’s public illumination, such as maintenance or damage, storage management of public illumination components, and alert system integration. The current methods the Public Illumination Division uses are considered inefficient and outdated, and this work tries to contribute to that. The business rules integration will try to improve the features mentioned above by providing an automated alternative to some processes that are very costly with current outdated mechanisms. This implementation is a particular challenge in this project because of the current deprecated status of most public applications, as technological usage is not yet very well integrated within public divisions. This fact is also part of this work, creating a case study to compare the technological knowledge between private and public organizations. This study served as a knowledge base for getting a better context of the SIIP application. This work explains all the phases that a project of this kind should consider, including research about related applications and why Business Rules are essential, context gathering of the environment, client and application, and the development process of developing the application and creating an integration proposal of the Business Rules within the ap plication in order to promote better technological optimization within organizations. To further sustain the thesis of why Business Rules is an essential subject to this work, a case study was created and conducted, inquiring voluntary people about how public and private organizations differ in technological advances, difficulties, and access provision. At a final stage, the Business Rules integration proposal is then applied, which includes prototyping and development of the whole structure needed to integrate the Business Rules within the SIIP system, trying to promote its use to improve efficiency and better workflows
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