Enabling global experiments with interactive reconfiguration and steering by multiple users

In global scientific experiments with collaborative scenarios involving multinational teams there are big challenges related to data access, namely data movements are precluded to other regions or Clouds due to the constraints on latency costs, data privacy and data ownership. Furthermore, each site is processing local data sets using specialized algorithms and producing intermediate results that are helpful as inputs to applications running on remote sites. This paper shows how to model such collaborative scenarios as a scientific workflow implemented with AWARD (Autonomic Workflow Activities Reconfigurable and Dynamic), a decentralized framework offering a feasible solution to run the workflow activities on distributed data centers in different regions without the need of large data movements. The AWARD workflow activities are independently monitored and dynamically reconfigured and steering by different users, namely by hot-swapping the algorithms to enhance the computation results or by changing the workflow structure to support feedback dependencies where an activity receives feedback output from a successor activity. A real implementation of one practical scenario and its execution on multiple data centers of the Amazon Cloud is presented including experimental results with steering by multiple users.info:eu-repo/semantics/publishedVersio

Web Portal for Professional Financial Services

The financial services industry offers great opportunities both for the investors and for the companies providing services to the investors. Most of the existing Web sites offer similar services such as stock/index/options quotes, markets overview, most active issues, etc. On other side, there are various tools for technical analysis, charting, and stocks screening. The paper presents a newly developed Web portal for Professional Financial Services called MFinance that offers for the retail investors the services mentioned over. It provides a detailed explanation of the business cases and the essential functionalities of the portal and the way of their realization based on Java server-side technologies. Special attention is dedicated to the definition and evaluation of trading strategies and to stock screening based on these trading strategies

The role of parallel computing in bioinformatics

The need to intelligibly capture, manage and analyse the ever-increasing amount of publicly available genomic data is one of the challenges facing bioinformaticians today. Such analyses are in fact impractical using uniprocessor machines, which has led to an increasing reliance on clusters of commodity-priced computers. An existing network of cheap, commodity PCs was utilised as a single computational resource for parallel computing. The performance of the cluster was investigated using a whole genome-scanning program written in the Java programming language. The TSpaces framework, based on the Linda parallel programming model, was used to parallelise the application. Maximum speedup was achieved at between 30 and 50 processors, depending on the size of the genome being scanned. Together with this, the associated significant reductions in wall-clock time suggest that both parallel computing and Java have a significant role to play in the field of bioinformatics

Generic framework for the personal omni-remote controller using M2MI

A Generic Framework for the Personal Omni-Remote Controller Using M2MI is a master’s thesis outlining a generic framework for the wireless omni-remote controller that controls neighboring appliances by using Many-to-Many Invocation (M2MI). M2MI is an object-oriented abstraction of broadcast communication. First, this paper introduces the history of remote controllers and analyzes omni-remote controller projects made by other researchers in this area, such as the Pebbles PDA project at Carnegie Mellon University and HP’s COOLTOWN project. Second, this paper depicts a generic framework of the personal omni-remote controller system including architecture, type hierarchy, and service discovery. In this framework, a module approach and a decentralized dual-mode service discovery scheme are introduced. When users request a certain type of service, their omni-remote controller application will first discover the available appliances in the vicinity and then bring up the corresponding control module for the target appliance. Thus, users can control the appliance through the User Interface of the control module. To join the omni-remote controller system, servers and clients need to follow the type hierarchy convention of the system. Finally, several implementations are given to show the control of different appliances with different capabilities. These appliances include thermostats, TVs with parental control, and washing machines

Environment Orientation : a structured simulation approach for agent-based complex systems

Complex systems are collections of independent agents interacting with each other and with their environment to produce emergent behaviour. Agent-based computer simulation is one of the main ways of studying complex systems. A naive approach to such simulation can fare poorly, due to large communication overhead, and due to the scope for deadlock between the interacting agents sharing a computational platform. Agent interaction can instead be considered entirely from the point of view of the environment(s) within which the agents interact. Structuring a simulation using such Environment Orientation leads to a simulation that reduces communication overhead, that is effectively deadlock-free, and yet still behaves in the manner required. Additionally the Environment Orientation architecture eases the development of more sophisticated large-scale simulations, with multiple kinds of complex agents, situated in and interacting with multiple kinds of environments. We describe the Environment Orientation simulation architecture. We report on a number of experiments that demonstrate the effectiveness of the Environment Orientation approach: a simple flocking system, a flocking system with multiple sensory environments, and a flocking system in an external environment

Active Space : executando operações no espaço de tuplas

Monografia (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2014.Sistemas distribuídos baseados em coordenação possuem uma forma única de comunicação através de Espaço de Tuplas. Nesse tipo de comunicação apenas uma tupla pode ser inserida, lida ou removida por primitivas de coordenação que acessam tais espaços. Lidar com um grande número de tuplas pode ser desafiador no sentido de como estas tuplas serão buscadas e recuperadas. Propomos a criação de um sistema de query e novas operações de consulta para ler todas as tuplas disponíveis em um Espaço de Tuplas e minimizar a quantidade de dados transferidos pela rede a partir dos servidores. Uma contribuição de Espaços de Tuplas ativos (Active Spaces) que suportem estas operações corresponde a proporcionar mais flexibilidade para usuários. Um Active Space visa também assegurar uma entrega de tuplas confiáveis e de maneira segura na medida em que buscas complexas são realizadas, e a porção de dados e a rede aumentem.Distributed coordination-based systems have a unique form of communication through a tuple space. In this type of communication only one tuple can be inserted, read, or removed by coordination primitives that access such spaces. Dealing with a great number of tuples is challenging in the sense of how these tuples will be searched and retrieved. We propose the creation of a query system and new query operations to read all available tuples in the tuple space and minimize the quantity of transferred data from the servers through the network. A contribution of active tuple spaces (Active Spaces) that support these operations corresponds to give more flexibility to users. An Active Space also aims to assure a delivery of trusty tuples and in a secure way to the extent that complex searches are executed, and the amount of data and the network grow

A Model for Scientific Workflows with Parallel and Distributed Computing

In the last decade we witnessed an immense evolution of the computing infrastructures in terms of processing, storage and communication. On one hand, developments in hardware architectures have made it possible to run multiple virtual machines on a single physical machine. On the other hand, the increase of the available network communication bandwidth has enabled the widespread use of distributed computing infrastructures, for example based on clusters, grids and clouds. The above factors enabled different scientific communities to aim for the development and implementation of complex scientific applications possibly involving large amounts of data. However, due to their structural complexity, these applications require decomposition models to allow multiple tasks running in parallel and distributed environments. The scientific workflow concept arises naturally as a way to model applications composed of multiple activities. In fact, in the past decades many initiatives have been undertaken to model application development using the workflow paradigm, both in the business and in scientific domains. However, despite such intensive efforts, current scientific workflow systems and tools still have limitations, which pose difficulties to the development of emerging large-scale, distributed and dynamic applications. This dissertation proposes the AWARD model for scientific workflows with parallel and distributed computing. AWARD is an acronym for Autonomic Workflow Activities Reconfigurable and Dynamic. The AWARD model has the following main characteristics. It is based on a decentralized execution control model where multiple autonomic workflow activities interact by exchanging tokens through input and output ports. The activities can be executed separately in diverse computing environments, such as in a single computer or on multiple virtual machines running on distributed infrastructures, such as clusters and clouds. It provides basic workflow patterns for parallel and distributed application decomposition and other useful patterns supporting feedback loops and load balancing. The model is suitable to express applications based on a finite or infinite number of iterations, thus allowing to model long-running workflows, which are typical in scientific experimention. A distintive contribution of the AWARD model is the support for dynamic reconfiguration of long-running workflows. A dynamic reconfiguration allows to modify the structure of the workflow, for example, to introduce new activities, modify the connections between activity input and output ports. The activity behavior can also be modified, for example, by dynamically replacing the activity algorithm. In addition to the proposal of a new workflow model, this dissertation presents the implementation of a fully functional software architecture that supports the AWARD model. The implemented prototype was used to validate and refine the model across multiple workflow scenarios whose usefulness has been demonstrated in practice clearly, through experimental results, demonstrating the advantages of the major characteristics and contributions of the AWARD model. The implemented prototype was also used to develop application cases, such as a workflow to support the implementation of the MapReduce model and a workflow to support a text mining application developed by an external user. The extensive experimental work confirmed the adequacy of the AWARD model and its implementation for developing applications that exploit parallelism and distribution using the scientific workflows paradigm

Escalonamento baseado em espaços de tuplas para grades computacionais

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia ElétricaO escalonamento em grades envolve um grande número de tarefas. Estas incluem a busca de recursos em uma coleção de sistemas computacionais heterogêneos geograficamente distribuídos e a tomada de decisão de quais destes recursos usar. Apesar dos esforços dos escalonadores de grades atuais, estes possuem alguma dificuldade de garantir um bom escalonamento devido a natureza dinâmica da grade, isto é, a disponibilidade e a capacidade dos recursos da grade mudam dinamicamente. As informações sobre os recursos usadas pelos escalonadores são providas por um serviço de informação. Porém, o uso destas informações podem levar a escalonamentos que não são muito próprios devido a desatualização das mesmas. A principal contribuição desta tese é a proposta de uma nova infra-estrutura de escalonamento para grades computacionais, denominada GRIDTS. Nesta infra-estrutura os recursos é que são os responsáveis pela seleção das tarefas a serem executadas. Esta seleção é feita de acordo com as capacidades momentâneas do recurso. Lembrando que no escalonamento tradicional a busca é feita pelos escalonadores, os quais procuram recursos apropriados para as tarefas disponíveis, a abordagem proposta elimina a necessidade de um serviço de informação. Os recursos conhecem suas situações instantâneas permitindo a obtenção de bons escalonamentos. Portanto, a nossa proposta evita escalonamentos baseados em informações não precisas. A definição da infra-estrutura proposta está fortemente baseada na coordenação por espaço de tuplas. A infra-estrutura proposta também provê um escalonamento tolerante a faltas através da combinação de um conjunto de técnicas de tolerância a faltas. O GRIDTS é avaliado através de provas de correção, assim como por simulações. Os resultados obtidos demonstram que o GRIDTS é uma solução viável e que consegue atingir seus objetivos de modo eficiente, lidando com faltas sem afetar significativamente o escalonamento

Provendo privacidade no modelo de coordenação por Espaço de Tuplas

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2018.A coordenação entre processos se configura como um grande desafio no desenvolvimento de sistemas distribuídos. Um dos modelos utilizados para realização de coordenação entre processos temporal e espacialmente desacoplados é por Espaços de Tuplas, que consiste em uma implementação de memória compartilhada que provê armazenamento e recuperação de objetos de dados chamados tuplas. Buscas de tuplas são realizadas de modo associativo, através do conteúdo de seus campos. Este tipo de acesso pode impedir que haja privacidade dos dados armazenados, tornando-as vulneráveis a uma série de ataques, já que os servidores precisam acessar dados em claro para realizar buscas. Com o objetivo de sanar este problema, este trabalho apresenta propostas visando prover privacidade no sistema DepSpace, um sistema de coordenação que implementa mecanismos de tolerância a falhas e confiabilidade combinadas com aspectos de segurança. A ideia principal é utilizar esquemas criptográficos de computação privativa, que possibilitam a busca e computação sobre dados cifrados. Assim, os servidores podem operar sobre dados sem tomarem conhecimento dos mesmos. O sistema resultante além de prover privacidade, aumenta suas funcionalidades, tornando-se mais flexível. Apresentamos ainda uma análise de segurança do sistema com as melhorias propostas, juntamente com sua análise de desempenho, explicitando o impacto causado pelos algoritmos criptográficos. Experimentos foram realizados aplicando as propostas à coordenação distribuída extensível, um modelo que utiliza computação dos dados nos servidores para tornar a coordenação mais ágil. Os resultados mostram uma redução de até 90% na latência do sistema e um aumento de até quase 9x na vazão (throughput) no processamento de mecanismos de coordenação em comparação à abordagem tradicional não extensível.The coordination of distributed processes is a big challenge in the development of dis- tributed applications. Tuple spaces provide a model for processes coordination that is decoupled in space and time. Conceptually, tuple spaces are shared memory objects that provide operations to store and retrieve ordered sets of data, called tuples. Tuples stored in a tuple space are accessed by the contents of their fields, working as an associative memory. This kind of access could impair user and data privacy, making these Systems susceptible to several types of attacks since servers need to access plaintext data to search for tuples. In order to deal with this problem, this work proposes mechanisms to provide privacy on DepSpace, a fault-tolerant coordination system that combines dependability and security properties. The main idea is to use privacy-preserving cryptography schemes, that allow search and computation over encrypted data. Consequently, servers could operate over data without knowing them. Beyond to provide privacy, the resulting system increases its functionalities, being more flexible. This work also presents a security analysis of the system with the proposed improvements, together with its performance analysis that shows the impact caused by the cryptographic algorithms. A set of experiments was implemented applying this proposals for extensible distributed coordination, a model that uses data computing on the servers side to make the coordination faster. The results show that it could bring a reduction of up to 90% on the system latency and increase almost 9x its throughput on processing coordination mechanisms, comparing to the non-extensible traditional approach