Systems of distributed character are increasing in size and becoming more complex. Managing and adapting to constant changes of requirements is a challenge during the entire system development life cycle. While new functionalities are implemented, the software may change in design and may lead to poor software quality and increased system complexity. This thesis focuses on tackling the complexity issue in a distributed Electronic Warfare system used in military aircraft. The system consists of a server and several clients which acts as publishers or subscribers for different events sent in the system. The communication is based on unicast and uses a publish/subscribe pattern for the client nodes to register as publishers or subscribers to the server. The system is created to handle message passing in high rate and is sensitive for message delays. Due to this, the system is dependent on a reliable network structure with a continuous necessity for development. An implementation of a multicast prototype will be replacing the topic-specific unicast communication and the publish/subscribe registration process to the server. The system will be evaluated by a comparison of the old communication version with the new multicast implementation using software metrics. The result is to evaluate if the behavior and functionality of the distributed Electronic Warfare system change. / System av distribuerad karaktär ökar i storlek och blir alltmer komplex. Att hantera och anpassa sig till ständiga kravändringar är emellertid en utmaning under hela systemets utvecklingsprocess. Medan nya funktioner implementeras kan mjukvaran ändras i design vilket kan leda till dålig programkvalitet och ökad systemkomplexitet. Denna rapport fokuserar på att hantera komplexiteten i ett distribuerat telekrigföringssystem som används i militära flygplan. Systemet består av en server och flera klienter som publicerar och prenumererar för olika typer av meddelanden som skickas i systemet. Kommunikationen baseras på enkelsändning och använder ett publish/subscribe meddelandemönster där klienterna registrerar sig som publicerare eller prenumeranter till servern. Systemet är skapat för att kunna hantera höga meddelandehastigheter och har låg tolerans för meddelandeförseningar. På grund av detta är tillförlitlighet i nätverksstrukturen ett essentiellt kvalitetsattribut då nätverket är i behov av en ständig utveckling. En prototyp av multisändning kommer att implementeras och ersätta kommunikationen baserad på enkelsändning och publish/subscribe registreringsprocessen till servern. Systemet kommer att utvärderas genom en jämförelse av den gamla kommunikationsversionen av systemet med den nya multicast-implementeringen med hjälp av mjukvarukomplexitetsmätningar. Resultatet är att utvärdera om beteendet och funktionaliteten hos det distribuerade telekrigföringssystemet ändras.

A flexible, scalable, and asynchronous middleware abstract is needed for business process management, which involves thousands of tasks and a large number of running instances of large business processes. The content-based publish/subscribe system is an ideal candidate to serve as enterprise service bus for these applications. In the publish/subscribe paradigm, information providers called publishers disseminate publications to all subscribers who have expressed interests by registering subscriptions through a loosely coupled interface. However, the traditional publish/subscribe paradigm only supports stateless subscriptions, that is, event correlation is ignored. Moreover, subscribers can only receive publications issued after their subscriptions. There are many application contexts, however, where access to publications from the past is necessary,such as for replaying a business process execution to debug it. Even more interesting uses arise when data from the past can be correlated with those in the future. Therefore, new languages and new functionalities are needed in the standard publish/subscribe model in order to support business process management. A new subscription language PADRES SQL(PSQL) which can express event patterns and unify both historic and future views for subscribers. PADRES allows a subscriber to access data published both in the past and in the future. Furthermore, complex event detection happens in the broker network. The main difficulties of distributed event detection are routing a composite subscription, including where and how to decompose the composite subscription, and routing the individual parts of the subscription. Our composite subscription routing decisions are based on a cost model which minimizes the routing and detection delay. An adaptive subscription routing protocol is proposed to determine efficient location with dynamic changing workloads. PADRES also provides robust message delivery by exploring alternative paths in a cyclic overlay. Routing optimizations and efficient matching algorithms are studied to improve the performance of the extended publish/subscribe model. With the above features, we propose the Ninos system, the distributed business process execution architecture as a case study,which uses light-weight activity agents to carry out business process execution in a distributed environment. Ninos proves that decentralized business process execution is the trend for next generation products, and the publish/subscribe model is ideal to serve as an enterpriser service bus (ESB) for distributed applications.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-05-24T16:53:14Z No. of bitstreams: 1 Ivam Guilherme Wendt_.pdf: 2573131 bytes, checksum: 364b08dccce8d5d89f93cdf8605772d8 (MD5) / Made available in DSpace on 2017-05-24T16:53:14Z (GMT). No. of bitstreams: 1 Ivam Guilherme Wendt_.pdf: 2573131 bytes, checksum: 364b08dccce8d5d89f93cdf8605772d8 (MD5) Previous issue date: 2017-02-23 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A Internet das Coisas (IoT - Internet of Things) é considerada a próxima grande evolução na era da computação após a Internet. Na Internet das Coisas muitos objetos que nos rodeiam serão conectados em redes e se comunicarão entre sí sem auxílio ou intervenção humana. Implementações de grande escala têm potencial para criar um enorme tráfego agregado. Muitas vezes Brokers ou Intermediários, são utilizados para possibilitar esta comunicação machine-to-machine (M2M), utilizando o modelo de comunicação Publish/- Subscribe que possui diversas bibliotecas particulares para uso na Internet das Coisas. Alguns trabalhos desenvolvidos pela comunidade visam tratar o desempenho no ambiente de Brokers Publish/Subscribe, no entanto impõem modificações e restrições quanto aos Brokers e arquitetura utilizada. Neste cenário, visando atender a necessidade de escalabilidade citada, é proposto um modelo de elasticidade chamado PSElastic. PSElastic fornece um modelo de elasticidade multinível para Brokers Publish/Subscribe, fazendo uso da elasticidade provida pela Computação em Nuvem, sem afetar o desempenho do sistema e sem a necessidade de investimentos ou ajustes por parte dos clientes e aplicações que fazem uso deste modelo. O modelo oferece a elasticidade de forma automática, reativa e multinível, onde multinível refere-se aos níveis de Broker e de Orquestrador do modelo. Buscando avaliar o modelo PSElastic foram definidos três cenários diferentes para a execução dos testes: Cenário 1, sem elasticidade; Cenário 2, elasticidade na camada de Brokers e Cenário 3, elasticidade multinível. Diferentes limites de réplicas de máquinas virtuais foram utilizados, assim como combinações de thresholds para avaliar o Tempo de Execução, quantidade de Mensagens por Segundo tratadas e a Eficiência na utilização dos recursos computacionais. PSElastic apresentou excelentes resultados ao reduzir em até 81,2% o tempo necessário para o tratamento de uma carga de dados e aumentar o throughput do ambiente com Broker Mosquitto de 54,95 mensagens por segundo (Mps) para 235,29 Mps e de 38,02 Mps para 202,02 Mps no ambiente com Broker RabbitMQ. / The Internet of Things (IoT) is considered the next big evolution in the computing era after the Internet. In Internet of Things many objects around us will be connected in networks and will communicate among themselves without assistance or human intervention. Large scale implementations has potential to create a huge aggregate traffic. Often brokers or intermediaries, are used to enable this machine-to-machine (M2M) communication using the Publish/Subscribe communication model that has several private libraries for use in Internet of Things. Some works developed by the community aim to treat performance in Publish/Subscribe brokers environment, however impose modifications and restrictions regarding brokers and architecture used. In this scenario, aiming to fulfill the need for cited scalability, we propose a elasticity model called PSElastic. The model provides an model with multilevel elasticity for Publish/Subscribe Brokers, making use of the elasticity promoted by cloud computing, not affecting system performance and without the need for investments or adjustments by customers and applications that make use of this model. PSElastic offers elasticity in the following manners: automatic, reactive and uses the multilevel elasticity, where multilevel refers to Broker level and Orchestrator model. In order to evaluate the model PSElastic, three different scenarios for execution of tests were defined: Scenario 1, without elasticity; Scenario 2, elasticity in the layer of Broker and Scenario 3, multilevel elasticity. Different limits of replica of virtual machines were used, as well as thresholds to evaluate Execution Time, number of Messages per Second handled and Efficiency in the use of computational resources. PSElastic showed excellent results by reducing the time needed to handle a data load by up to 81.2% and increase the throughput of the environment with Mosquitto Broker from 54.95 messages per second (Mps) to 235.29 Mps and from 38.02 Mps to 202.02 Mps in the environment with RabbitMQ Broker.

L’objectif de cette thèse est la gestion de la QdS des systèmes publier/souscrire sur MANET. Ceci provoque un maintien permanent de la connectivité entre les parties communicantes du système. Plus précisément, les contributions de cette thèse, sont organisées autour de deux grands axes relatifs aux modules de monitoring et d’analyse de la QdS de ces systèmes dans un contexte ad-hoc. Ceci englobe les etapes de collecte des paramètres de QdS au cours du fonctionnement du système, et de détection des dégradations pouvant l’affecter.Contrairement à ce qui existe dans la littérature, notre module d’analyse, basé sur des méthodes statistiques, se base sur des seuils adaptatifs qui tiennent en comptes de la dynamicité du réseau et des changements affectant le contexte ad-hoc. En outre, le module d’analyse proposé offre à l’utilisateur une variété de choix entre une analyse réactive, proactive et hybride. Notre module permet aussi une localisation des pannes une fois détectées ou prédites. Des expérimentations menées à l’aide du simulateur Jist/Swans ont montré l’efficacité des modules developpés. De plus, une mesure des paramètres de performance du système avant et après introduction des modules développés a montré leur efficacité. Finalement, une étude de la complexité spatiale et temporelle du module analytique proposé a été réalisée. / Mobile ad-hoc networks (MANET) is a set of nodes, communicating meaning wireless channel without any centralized control. The main characteristic of MANET is the frequent mobility of its nodes leading to some dynamic changes of topology. Nodes mobility in such networks introduces possible disconnections between adjacent nodes, and more generally quality of service (QoS) degradation issues that do not fit well with QoS requirements of QoS sensitive applications. Publish/subscribe communicating system has been proposed at the middleware layer in order to communicate mobile entities in MANET. Such system is a decoupled interaction between publishers (or producers) and receivers (or consumers).Our goal in this thesis is to provide a QoS management for publish/subscribe systems when deployed on MANET while assuming a best effort flux at the routing layer. This thesis proposes an analytical model for latency aware publish/subscribe systems on mobile ad-hoc networks. The proposed approach combines both proactive and reactive statistical analysis.On the one hand, the reactive analysis, suitable for multimedia applications, detects failures by approximating latency series with Gumbel distribution. On the other hand, the proactive analysis, suitable for crisis management applications, forecasts failures occurrence relying on Auto Regression or Auto Regressive Integrated Moving Average Formulas. Finally, a hybrid analysis was proposed by dynamically switching from reactive to predictive forms of analysis whenever quality of service violations are noticed. In order to extract failure cause, we refer to the correlation method once failure was detected or predicted. Simulations done, using Jist/Swans simulator, under different scenariosproved the efficiency and accuracy of the proposed scheme.

The Publish/Subscribe (pub/sub) model has been widely applied in a variety of application scenarios which demand loose-coupling and asynchronous communication between a large number of information sources and sinks. In this model, clients are granted the flexibility to specify their interests at a high level and rely on the pub/sub middleware for delivery of their publications of interest. This increased flexibility and ease of use on the client side results in substantial complexity on part of the pub/sub middleware implementation. Furthermore, for several reasons including improved scalability, availability and avoiding a single point of failure, the pub/sub middleware is commonly composed of a set of collaborating message routers, a.k.a. brokers. The distributed nature of this design further introduces new challenges in ensuring end-to-end reliability as well as efficiency of operation. These challenges are largely unique to the pub/sub model and hence absent in both point-to-point or multicast protocols. This thesis develops solutions that ensure the dependable operation of the pub/sub system by exploiting the notion of overlay neighborhoods in a formal manner. More specifically, brokers maintain information about their neighbors within a configurable distance in the pub/sub overlay and exploit this knowledge to construct alternative forwarding paths or make smart forwarding decisions that improves efficiency, bandwidth utilization and delivery delay, all at the same time. Furthermore, in the face of failures overlay neighborhoods enable fast reconstruction of forwarding paths in the system without compromising its reliability and availability. Finally, as an added benefit of overlay neighborhoods, this thesis develops large-scale algorithms that bring the advantages of the pub/sub model to the domain of file sharing and bulk content dissemination applications. Experimental evaluation results with deployments as large as 1000 nodes illustrate that the pub/sub system scales well and outperforms the traditional BitTorrent protocol in terms of content dissemination delay.

We present fpga-ToPSS (Toronto Publish/ Subscribe System), an efficient FPGA-based middleware platform geared towards high-frequency and low-latency event processing. fpga-ToPSS is built over reconfigurable hardware---FPGAs---to achieve line-rate processing by exploiting unprecedented degrees of parallelism and potential for pipelining,only available through custom-built, application-specific and low-level logic design. Furthermore, our middleware solution hosts an event processing engine that is built on a hardware-based packet processor and Boolean expression matcher. Our middleware vision extends to a wide range of applications including real-time data analytics, intrusion detection, algorithmic trading, targeted advertisement, and (complex) event processing.

We present fpga-ToPSS (Toronto Publish/ Subscribe System), an efficient FPGA-based middleware platform geared towards high-frequency and low-latency event processing. fpga-ToPSS is built over reconfigurable hardware---FPGAs---to achieve line-rate processing by exploiting unprecedented degrees of parallelism and potential for pipelining,only available through custom-built, application-specific and low-level logic design. Furthermore, our middleware solution hosts an event processing engine that is built on a hardware-based packet processor and Boolean expression matcher. Our middleware vision extends to a wide range of applications including real-time data analytics, intrusion detection, algorithmic trading, targeted advertisement, and (complex) event processing.

Evolving smart infrastructures requires both content distribution as well as event notification and processing support. Content Centric Networking (CCN), built around named data, is a clean slate network architecture for supporting future applications. Due to its focus on content distribution, CCN does not inherently support Publish-Subscribe event notification, a fundamental building block in computer mediated systems and a critical requirement for smart infrastructure applications. While semantics of content distribution and event notification require different support systems from the underlying network infrastructure, content distribution and event notification can still be united by leveraging similarities in the routing infrastructure. Our Extended-CCN architecture(X-CCN) realizes this to provide lightweight content based pub-sub service at the network layer, which is used to provide advanced publish/subscribe services at higher layers. Light weight content based pub-sub and CCN communication at network layer along with advanced publish/subscribe together are presented as data fabric for the smart infrastructures applications.

Evolving smart infrastructures requires both content distribution as well as event notification and processing support. Content Centric Networking (CCN), built around named data, is a clean slate network architecture for supporting future applications. Due to its focus on content distribution, CCN does not inherently support Publish-Subscribe event notification, a fundamental building block in computer mediated systems and a critical requirement for smart infrastructure applications. While semantics of content distribution and event notification require different support systems from the underlying network infrastructure, content distribution and event notification can still be united by leveraging similarities in the routing infrastructure. Our Extended-CCN architecture(X-CCN) realizes this to provide lightweight content based pub-sub service at the network layer, which is used to provide advanced publish/subscribe services at higher layers. Light weight content based pub-sub and CCN communication at network layer along with advanced publish/subscribe together are presented as data fabric for the smart infrastructures applications.

A flexible, scalable, and asynchronous middleware abstract is needed for business process management, which involves thousands of tasks and a large number of running instances of large business processes. The content-based publish/subscribe system is an ideal candidate to serve as enterprise service bus for these applications. In the publish/subscribe paradigm, information providers called publishers disseminate publications to all subscribers who have expressed interests by registering subscriptions through a loosely coupled interface. However, the traditional publish/subscribe paradigm only supports stateless subscriptions, that is, event correlation is ignored. Moreover, subscribers can only receive publications issued after their subscriptions. There are many application contexts, however, where access to publications from the past is necessary,such as for replaying a business process execution to debug it. Even more interesting uses arise when data from the past can be correlated with those in the future. Therefore, new languages and new functionalities are needed in the standard publish/subscribe model in order to support business process management. A new subscription language PADRES SQL(PSQL) which can express event patterns and unify both historic and future views for subscribers. PADRES allows a subscriber to access data published both in the past and in the future. Furthermore, complex event detection happens in the broker network. The main difficulties of distributed event detection are routing a composite subscription, including where and how to decompose the composite subscription, and routing the individual parts of the subscription. Our composite subscription routing decisions are based on a cost model which minimizes the routing and detection delay. An adaptive subscription routing protocol is proposed to determine efficient location with dynamic changing workloads. PADRES also provides robust message delivery by exploring alternative paths in a cyclic overlay. Routing optimizations and efficient matching algorithms are studied to improve the performance of the extended publish/subscribe model. With the above features, we propose the Ninos system, the distributed business process execution architecture as a case study,which uses light-weight activity agents to carry out business process execution in a distributed environment. Ninos proves that decentralized business process execution is the trend for next generation products, and the publish/subscribe model is ideal to serve as an enterpriser service bus (ESB) for distributed applications.