Model-based provisioning and management of adaptive distributed communication in mobile cooperative systems

Adaptation of communication is required to maintain the reliable connection and to ensure the minimum quality in collaborative activities. Within the framework of wireless environment, how can host entities be handled in the event of a sudden unexpected change in communication and reliable sources? This challenging issue is addressed in the context of Emergency rescue system carried out by mobile devices and robots during calamities or disaster. For this kind of scenario, this book proposes an adaptive middleware to support reconfigurable, reliable group communications. Here, the system structure has been viewed at two different states, a control center with high processing power and uninterrupted energy level is responsible for global task and entities like autonomous robots and firemen owning smart devices act locally in the mission. Adaptation at control center is handled by semantic modeling whereas at local entities, it is managed by a software module called communication agent (CA). Modeling follows the well-known SWRL instructions which establish the degree of importance of each communication link or component. Providing generic and scalable solutions for automated self-configuration is driven by rule-based reconfiguration policies. To perform dynamically in changing environment, a trigger mechanism should force this model to take an adaptive action in order to accomplish a certain task, for example, the group chosen in the beginning of a mission need not be the same one during the whole mission. Local entity adaptive mechanisms are handled by CA that manages internal service APIs to configure, set up, and monitors communication services and manages the internal resources to satisfy telecom service requirements

Suporte à reconfiguração dinâmica de composições de serviços

Tese de mestrado em Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2010Uma das capacidades mais importantes dos sistemas computacionais nos dias que correm, é a possibilidade de estes permitirem a colaboração de diferentes unidades de processamento separadas fisicamente. Para que isto seja possível, cada um dos nós tem de ser capaz de trocar informação com os outros, tendo para isso que conhecer as regras que definem as características da ligação em si e o formato dos dados. Dada a complexidade das interacções estabelecidas, torna-se imperativo que sejam disponibilizados mecanismos às aplicações, que reúnam as funcionalidades que lhes permitam de forma facilitada efectuar o envio e recepção de dados. As plataformas de composição e execução de protocolos permitem a orquestração de protocolos com características bem definidas, disponibilizando às aplicações canais de comunicação com características complexas. As características da comunicação, variam quer pela mudança do requisitos das aplicações quer por alterações do ambiente de execução que tornam impossível garanti-las fisicamente. As plataformas devem permitir que as composições sejam alteradas dinamicamente com o menor custo para as aplicações, ou seja reduzindo ao máximo o tempo de inactividade ao mesmo tempo que asseguram a coerência das mensagens em trânsito. O Appia é uma plataforma de composição de protocolos desenvolvida com o propósito de permitir a composição de estruturas complexas e oferece à partida uma flexibilidade nas estruturas das composições, no entanto não permite que estas sejam modificadas em tempo de execução. O foco deste trabalho está direccionado para o estudo e implementação de um mecanismo de reconfiguração dinâmica que permita colmatar esta lacuna do Appia. Este objectivo foi conseguido pela evolução da plataforma no sentido de processar eventos de reconfiguração em tempo de execução. Na validação da solução proposta verificou-se que a degradação de desempenho é inferior a 15% e que as propriedades oferecidas pela plataforma não são afectadas.One of the most important capabilities of computer systems these days is the possibility that they allow the collaboration of different processing units physically separate. To make this possible, each of the nodes must be able to exchange information with the others, and must know which rules define the characteristics of the connection itself and the exchanged data format. Given the complex set of interactions, it is imperative that some mechanisms be available to applications, comprising the features that enable them to carry out an easier way to send and receive data. The platforms of composition and implementation of protocols allow the orchestration of well defined protocols, providing the applications with communication channels with complex traits. The characteristics of the communication required by the application change according to different requirements or by changes in the execution environment. The platforms should allow the compositions to be changed dynamically with the lowest cost for applications, which means, minimizing downtime while ensuring consistency of the messages being exchanged at that time. Appia is a protocol composition platform developed in order to support complex compositions structures and offers flexibility to match this requirement, but does not allow them to be modified at run time. The focus of this work is directed towards the study and implementation of a dynamic reconfiguration mechanism to bridge this gap. This was achieved by the extension of the existing platform implementation to handle reconfiguration events. The validation of the proposed solution includes the verification of the degradation of performance, which was found to be below 15% and also to guarantee that the reconfiguration does not affect the correct execution of Appia

Sistema electrónico basado en criterios de aprendizaje de máquina, para el reconocimiento de parámetros de calidad del agua, en el cultivo de truchas arco iris del criadero "Truchas aguas verdes"

Implementar un sistema electrónico de reconocimiento de parámetros de calidad del agua en el cultivo de truchas arco iris, mediante el uso del protocolo de comunicación MODBUS, para determinar que el ambiente de crianza de truchas influye en la mejora de la producción del criadero “Truchas Aguas Verdes”El objetivo principal de este estudio es la realización de un sistema de monitoreo de parámetros de calidad del agua. Para esto se ha realizado el proyecto en cuatro capítulos los cuales detallan todo el proceso de diseño, desarrollo e implementación. Y con ello evidenciar los beneficios que se pueden obtener en la producción de truchas con la instalación de este equipo en el criadero. Con la implementación de componentes de electrónica básica, programación de tarjetas microcontroladoras y manejo de datos.Ingenierí

Concurrency and dynamic protocol update for group communication middleware

The last three decades have seen computers invading our society: computers are now present at work to improve productivity and at home to enlarge the scope of our hobbies and to communicate. Furthermore, computers have been involved in many critical systems such as anti-locking braking systems (ABS) in our cars, airplane control systems, space rockets, nuclear power plants, banking and trading systems, medical care systems, and so on. The importance of these systems requires a high level of trust in computer-based systems. For example, a failure in a trading system (even if it is temporary) may result in severe economical losses. Hence coping with failures is a key aspect of computer systems. A common approach to tolerate failures is to replicate a system that provides a critical service, so that once a failure occurs on a given replica, the requests to the critical service are still executed by other replicas. This approach has the advantage of masking failures, i.e., requests to the service are continuously executed even in the presence of failures. However, replication introduces a performance cost, mainly because the execution of the service requests must be coordinated among all replicas. Furthermore, despite its apparent simplicity, replication is rather complex to implement. Replication is made easier by group communication which defines several abstractions that can be used by the designer of replicated systems. The group communication abstractions are implemented by distributed protocols that compose a group communication middleware. The aim of the thesis is to study two techniques to improve the performance of group communication middleware, and thus, reduce the cost of replication. First, we study dynamic protocol update, which allows group communication middleware to adapt to environment changes. More particularly, dynamic protocol update consists in replacing at runtime a given protocol composing the group communication middleware with a similar but more efficient protocol. The thesis provides several solutions to dynamic protocol update. For instance, we describe two algorithms to dynamically replace consensus and atomic broadcast, two essential protocols of a group communication middleware. Second, we propose solutions to introduce concurrency within a group communication middleware in order to benefit from the advantages offered by multiprocessor (or multicore) computers

Un environnement pour le calcul intensif pair à pair

Le concept de pair à pair (P2P) a connu récemment de grands développements dans les domaines du partage de fichiers, du streaming vidéo et des bases de données distribuées. Le développement du concept de parallélisme dans les architectures de microprocesseurs et les avancées en matière de réseaux à haut débit permettent d'envisager de nouvelles applications telles que le calcul intensif distribué. Cependant, la mise en oeuvre de ce nouveau type d'application sur des réseaux P2P pose de nombreux défis comme l'hétérogénéité des machines, le passage à l'échelle et la robustesse. Par ailleurs, les protocoles de transport existants comme TCP et UDP ne sont pas bien adaptés à ce nouveau type d'application. Ce mémoire de thèse a pour objectif de présenter un environnement décentralisé pour la mise en oeuvre de calculs intensifs sur des réseaux pair à pair. Nous nous intéressons à des applications dans les domaines de la simulation numérique et de l'optimisation qui font appel à des modèles de type parallélisme de tâches et qui sont résolues au moyen d'algorithmes itératifs distribués or parallèles. Contrairement aux solutions existantes, notre environnement permet des communications directes et fréquentes entre les pairs. L'environnement est conçu à partir d'un protocole de communication auto-adaptatif qui peut se reconfigurer en adoptant le mode de communication le plus approprié entre les pairs en fonction de choix algorithmiques relevant de la couche application ou d'éléments de contexte comme la topologie au niveau de la couche réseau. Nous présentons et analysons des résultats expérimentaux obtenus sur diverses plateformes comme GRID'5000 et PlanetLab pour le problème de l'obstacle et des problèmes non linéaires de flots dans les réseaux. ABSTRACT : The concept of peer-to-peer (P2P) has known great developments these years in the domains of file sharing, video streaming or distributed databases. Recent advances in microprocessors architecture and networks permit one to consider new applications like distributed high performance computing. However, the implementation of this new type of application on P2P networks gives raise to numerous challenges like heterogeneity, scalability and robustness. In addition, existing transport protocols like TCP and UDP are not well suited to this new type of application. This thesis aims at designing a decentralized and robust environment for the implementation of high performance computing applications on peer-to-peer networks. We are interested in applications in the domains of numerical simulation and optimization that rely on tasks parallel models and that are solved via parallel or distributed iterative algorithms. Unlike existing solutions, our environment allows frequent direct communications between peers. The environment is based on a self adaptive communication protocol that can reconfigure itself dynamically by choosing the most appropriate communication mode between any peers according to decisions concerning algorithmic choice made at the application level or elements of context at transport level, like topology. We present and analyze computational results obtained on several testeds like GRID’5000 and PlanetLab for the obstacle problem and nonlinear network flow problems

Context Adaptation of the Communication Stack

This paper presents a middleware framework to support the development of context-aware adaptive communication protocols, that can be reconfigured according not only to the local context, but also to the context of the remaining remote participants. The advantages of the framework are illustrated by using the concrete example of an adaptive group communication protocol. The protocol supports a distributed chat application that can be executed in both fixed PCs and mobile device

Context Adaptation of the Communication Stack

This paper presents a middleware framework to support the development of context-aware adaptive communication protocols, that can be reconfigured according not only to the local context, but also to the context of the remaining remote participants. The advantages of the framework are illustrated by using the concrete example of an adaptive group communication protocol. The protocol supports a distributed chat application that can be executed in both fixed PCs and mobile devices