Scalabale Group Communication Support for ATM Networks

In dieser Arbeit wird ein Ansatz vorgestellt, der eine skalierbare Gruppenkommunikationsunterstützung für ATM-Netze (SkaGAN) ermöglicht. Die herkömmliche rechnergestützte Kommunikation findet zwischen einem Sender und einem Empfänger statt. Die Gruppenkommunikation erweitert diese Form und erlaubt einer Gruppe von Rechnern untereinander zu kommunizieren. Diese Dissertation legt dabei den Fokus auf die ATM-Technologie (Asynchronous Transfer Mode), die keine akzeptable Gruppenkommunikationsunterstützung anbietet. Heutzutage wird ATM hauptsächlich in Backbone-Netzen eingesetzt, womit sich auch diese Arbeit auseinandersetzt. Der Schwerpunkt bei SkaGAN ist die Skalierbarkeit in Bezug auf Netzwerk- und Gruppengröße. Für den Bereich der lokalen ATM-Netze wird ebenfalls ein Lösungsvorschlag präsentiert, der eine Lastverteilung aktiver Gruppenteilnehmer auf mehrere Server beinhaltet. Der Lösungsansatz von SkaGAN für ATM-Weitverkehrsnetze orientiert sich an dem PNNI-Routingprotokoll und basiert auf einem hierarchischen Schema. Für die Verwaltung der Gruppen wird eine Baumhierarchie eingesetzt, die eine erhebliche Reduktion des Signalisierungsaufwandes und eine gute Skalierbarkeit ermöglicht. Für den Datentransfer zwischen den Gruppenteilnehmern wird ebenfalls eine Baumstruktur eingesetzt, die sich dynamisch an Änderungen in den Gruppen anpassen kann. Dabei wird die Anzahl der benötigten Zwischensysteme möglichst gering gehalten und die Lokalität der Teilnehmer berücksichtigt. Damit konnte auch in diesen Bereich eine gute Skalierbarkeit bei der Gruppenkommunikation erreicht werden.In this work, an approach is introduced, that enables scaleable group communication support for ATM networks (SkaGAN). The conventional computer supported communication takes place between one sender and one receiver. Group communication expands this form and allows a group of computers to communicate among each other. This dissertation puts its focus on the ATM technology (Asynchronous Transfer Mode), which offers no acceptable group communication support. Nowadays ATM is mainly utilized in backbone networks, wherewith this work deals. The focal point in SkaGAN is the scalability with regard to network and group sizes. In the area of local ATM networks a solution proposal is presented, that includes a load distribution of active group members on several servers. The approach for the solution of SkaGAN for ATM wide area networks orients itself on the PNNI routing protocol and is based on a hierarchical scheme. For the administration of the groups, a tree hierarchy is inserted, that enables a considerable reduction of the signaling expenses and a good scalability. For the data transfer between the group members also a tree structure is used, that can adapt itself dynamically to group changes. Thereby the amount of necessary intermediate systems is as small as possible and the location of the group members will be considered. Therewith also in this area a good scalability could be reached in the group communication

Diagnosing interoperability problems and debugging models by enhancing constraint satisfaction with case -based reasoning

Modeling, Diagnosis, and Model Debugging are the three main areas presented in this dissertation to automate the process of Interoperability Testing of networking protocols. The dissertation proposes a framework that uses the Constraint Satisfaction Problem (CSP) paradigm to define a modeling language and problem solving mechanism for interoperability testing, and uses Case-Based Reasoning (CBR) for debugging interoperability test cases. The dissertation makes three primary contributions: (1) Definition of a new modeling language using CSP and Object-Oriented Programming. This language is simple, declarative, and transparent. It provides a tool for testers to implement models of interoperability test cases. The dissertation introduces the notions of metavariables, metavalues and optional metavariables to improve the modeling language capabilities. It proposes modeling of test cases from test suite specifications that are usually used in interoperability testing performed manually by testers. Test suite specifications are written by organizations or individuals and break down the testing into modules of test cases that make diagnosis of problems more meaningful to testers. (2) Diagnosis of interoperability problems using search supplemented by consistency inference methods in a CSP context to support explanations of the problem solving behavior. These methods are adapted to the OO-based CSP context. Testers can then generate reports for individual test cases and for test groups from a test suite specification. (3) Detection and debugging of incompleteness and incorrectness in CSP models of interoperability test cases. This is done through the integration of two modes of reasoning, namely CBR and CSP. CBR manages cases that store information about updating models as well as cases that are related to interoperability problems where diagnosis fails to generate a useful explanation. For the latter cases, CBR recalls previous similar useful explanations

O potencial da IOT nas autarquias locais: o caso da recolha de RSU em Setúbal

A chegada de novas tecnologias pode mudar toda uma forma de executar atividades ou processos, tornando-os mais eficientes, mais baratos e sustentáveis. A Internet of Things ou Internet das Coisas (em português), veio revolucionar a forma como ligamos simples objetos à internet podendo assim efetuar comunicações bilaterais com os mesmos. Neste preciso momento, as mais variadas marcas estão a adaptar os seus produtos a esta nova realidade, quer seja com o objetivo de se tornarem mais competitivos ou como seguidores dos mais inovadores. No âmbito dos governos e dos serviços públicos, mais precisamente das câmaras municipais, o objetivo destas organizações é servir as populações e prestar-lhes o melhor serviço possível, tendo em conta a limitação de recursos, sejam eles financeiros, humanos ou materiais. Na realidade, o grande desafio é a gestão dos recursos limitados existentes conseguindo um patamar de eficiência que permita consolidar as necessidades aos recursos disponíveis e, em situações mais extremas, conseguir uma redução de custos. Para este projeto e de entre as várias áreas em que é possível idealizar projetos de IoT a desenvolver numa Câmara Municipal, foi escolhida a área do ambiente, mais precisamente a recolha dos Resíduos Sólidos Urbanos (RSU). A escolha desta atividade recai principalmente devido à alta visibilidade e importância junto das populações, mas também porque a mesma é regida pelo princípio do utilizador-pagador em que o munícipe paga pelos resíduos que produz. Caso seja possível uma redução de custos, as populações serão as principais beneficiadas. O projeto em estudo possui duas fases distintas: uma primeira que consiste na elaboração de um protótipo de verificação do funcionamento técnico e uma segunda fase que compreende o estudo do impacto económico e financeiro da aplicação do protótipo na recolha dos resíduos sólidos urbanos. A primeira fase descreve sucintamente em que consiste o protótipo construído, nomeadamente os seus componentes, o funcionamento dos mesmos e a forma de assemblagem. A segunda fase analisa detalhadamente os custos envolvidos na atividade de recolha de RSU, o investimento necessário ao desenvolvimento do projeto e é investigada uma possível redução de custos perante três cenários distintos de redução de paragens nas rotas de recolha de RSU. A redução de custos proposta assenta na utilização do protótipo descrito na primeira fase com base na IoT que, uma vez instalado em cada contentor de recolha de RSU, efetua uma leitura xii volumétrica, indicando um valor de preenchimento. Ao efetuar leituras diárias a cada contentor permite saber quais os contentores que não necessitam de recolha, informando o motorista da viatura de recolha que hoje a sua rota terá menos pontos de recolha que o habitual ou até mesmo uma nova rota, otimizando a recolha dos RSU e atingindo uma redução de custos operacionais. A análise financeira efetuada envolve os custos de implementação do dispositivo em cada um dos contentores, os custos diretos dos recursos humanos afetos apenas à recolha dos RSU e os custos operacionais das viaturas, assim como a poupança conseguida. Considerando os custos de implementação como um investimento, o estudo conclui que o payback do projeto é inferior a 22 meses em qualquer dos cenários analisados. Perante esta avaliação, podemos considerar que este é um projeto certamente a desenvolver, podendo dar inicio à transformação de uma cidade num laboratório de criação de uma smart city, utilizando o know-how técnico existente na Câmara Municipal e a visão estratégica para o futuro da cidade.The arrival of new technologies can change a whole way of executing activities or processes, making them more efficient, cheaper and sustainable. The Internet of Things, has revolutionized the way we link simple objects to the Internet with the ability to make making bilateral communications. At this very moment, the most varied brands are adapting their products to this new reality, whether with the goal of becoming more competitive or as followers of the most innovative companies. By creating these products, companies want to reach a wide range of stakeholders, from manufacturers to developers, always having sales as their primary goal. Throughout the life cycle of a product, it has several target audiences, starting in large companies (and in some government), and only afterwards the common end consumers, mainly due to the high sale price of the products at its launch, not all stakeholders have the financial capacity to invest in new technologies. In the context of governments and public services, specifically municipal councils, the objectives of these organizations are always to serve the population and provide them with the best possible service, considering the limited resources, be they financial, human or material. The great challenge is to manage the existing limited resources and achieve a level of efficiency that allows to consolidate the needs to available resources and in extreme situations, to achieve a reduction of costs. For this project and among the various areas in which it is possible to design IoT projects to be developed in a City Hall, the chosen area was the environment, more specifically the collection of Municipal Solid Waste (MSW). The choice of this activity is mainly due to the high visibility and importance to the populations, but also because it is governed by the user-pays principle in which the citizen pays for the waste that he produces. If it is possible to reduce costs, populations will be the main beneficiaries. The project under study has two distinct phases: a first one consisting of the elaboration of a prototype of verification of the technical operation and a second phase that includes the study of the economic and financial impact of the application of the prototype in the collection of municipal solid waste. The first phase briefly describes the prototype designed, namely its components, their operation and the form of assembly. The second phase analyses in detail all the costs involved in the MSW collection activity, with a special focus on direct costs (fuel and human resources), and a possible reduction of costs is investigated in the face of three distinct scenarios for the reduction of stops on MSW collection routes. The proposed cost reduction is based on the use of the prototype described in the first stage based on IoT, which once installed in each MSW collection container, can do volumetric reading, indicating a fill value. When doing daily readings to each container, it is possible to know which containers do not need to be collected, informing the driver of the vehicle that today his route will have fewer collection points than usual or even a new route, optimizing the collection of MSW and reaching a reduction in operating costs. The analysis involves the costs of implementing the device in each of the containers, the direct costs of the human resources concerned only to the collection of MSW and the operating costs of the vehicles, as well as the savings achieved. Considering the implementation costs as an investment, the study concludes that the project payback point is less than 22 months in any of the scenarios analysed. Given this evaluation, we can consider that this is a project certainly to be developed and can start the transformation of a city into a laboratory to create a smart city, using the technical know-how existing in the organization and the strategic vision for the future of a city