In recent years, there has been growing support for more tightly coupled applications regarding heterogeneous resources. A specific way of obtaining better performance in such applications is to consider the replacement of execution entities by newer resources during the application's lifetime. Therefore, this article describes the rationale for developing jMigBSP, which is a Java programming library that offers object rescheduling for round-based applications. In this context, the proposal addresses Bulk Synchronous Parallel (BSP) applications because BSP represents one of the most often used models for writing tightly coupled parallel programs. jMigBSP's main contribution examines the rescheduling facility in two different ways: (i) using migration directives in the application code directly; and (ii) through automatic load balancing at the middleware level. Specifically, this second idea is feasible because of Java's inheritance feature, which transforms a simple jMigBSP application into a migratable one by changing only a single line of code. In addition to the description of jMigBSP, this article emphasizes the benefits of using migration over heterogeneous environments by executing scientific applications. The results indicate gains of up to 56% with object rescheduling and support the feasibility of using migration as a load balancing technique. The migration of objects to different resources becomes increasingly important for tightly coupled applications because resource availability and application behavior can vary over time on grid environments. The use of a rescheduling technique enables on-the-fly load balancing to reduce the application's time. This dynamic rescheduling could transfer objects from overloaded to underloaded resources or reallocate objects with higher communications patterns in the same cluster. Rescheduling is especially important on long-running applications, which are characterized as CPU intensive, or on large-volume data transfers, because the newly optimized organization can be used at least to amortize the migration penalties [2].Currently, research in the rescheduling field includes the definition of unified metrics for acting in response to application and resource dynamics and user-friendly programming interfaces for providing both application's modeling and replacement facilities [8,9]. Technically, we can benefit from process migration either by modifying the application source code or by using migration-aware communication middleware [10]. The former represents an explicit approach, which usually consists of including migration directives or implementing receiver-initiated load balancing algorithms inside the application's code. The latter is commonly an extension of the programming library for providing a transparent and effortless migration mechanism from the user's point of view. Considering these characteristics, this last approach represents an implicit way of providing migration from the developer's perspective.In this regard, we could ask which is the best approach...

This paper describes the rationale for developing jMigBSP -a Java programming library that offers object rescheduling. It was designed to work on grid computing environments and offers an interface that follows the BSP (Bulk Synchronous Parallel) style. jMigBSP's main contribution focuses on the rescheduling facility in two different ways: (i) by using migration directives on the application code directly and (ii) through automatic load balancing at middleware level. Especially, this second idea is feasible thanks to the Java's inheritance feature, in which transforms a simple jMigBSP application in a migratable one only by changing a single line of code. In addition, the presented library makes the object interaction easier by providing one-sided message passing directives and hides network latency through asynchronous communications. Finally, a BSP-based FFT application was developed and its execution shows jMigBSP as a competitive library when comparing performance with a C-based library called BSPlib. Besides its user-friendly Java interface, the strengths of jMigBSP also considers the migration tests where it outperforms the time spent with BSPlib.

This article describes the rationales for developing jMigBSP-a Java programming library that offers object rescheduling. It was designed to work on grid computing environments and offers an interface that follows the BSP (Bulk Synchronous Parallel) style. jMigBSP's main contribution focuses on the rescheduling facility in two different ways: (i) by using migration directives on the application code directly and (ii) through automatic load balancing at middleware level. Especially, this second idea is feasible thanks to the Java's inheritance feature, in which transforms a simple jMigBSP application in a migratable one only by changing a single line of code. In addition, the presented library makes the object interaction easier by providing one-sided message passing directives and hides network latency through asynchronous communications. Finally, we developed three BSP applications: (i) Prefix Sum; (ii) Fractal Image Compression (FIC) and; (iii) Fast Fourier Transform (FFT).They show our library as viable solution to offer load balancing on BSP applications. Specially, the FIC results present gains up to 37% when applying migration directives inside the code. Finally, the FFT tests emphasize strength of jMigBSP. In this situation, it outperforms a native library denoted BSPlib when migration facilities take place.

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Today, we observe that more and more, radio frequency identification (RFID) technology has been used to identify and track objects in enterprises and institutions. In addition, we also perceive the growing adoption of cloud computing, either public or private, to process and store data from the objects. In this context, the literature does not present an initiative that looks into the network on enterprise-cloud interactions, so neglecting network performance and congestion information when transmitting data to the cloud. Thus, we are presenting a model named ACMA-Automatic Control and Management of Assets. ACMA employs context awareness to control and monitor corporate assets in companies with multiple units. ACMA provides a centralized point of access in the cloud in which interested actors can get online data about each corporate asset. In particular, our scientific contribution consists in considering network congestion to control dynamically the data updating interval from sensors to the cloud. The idea is to search for reliability and integrity of operations, without losing or corrupting data when updating the information to cloud. Thus, this article describes the ACMA model, its architecture, algorithms and features. In addition, we describe the evaluation methodology and the results obtained through experiments and simulations based on the developed prototype.

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Este artigo tem como objetivo apresentar as idéias para o desenvolvimento de um framework para balanceamento de carga chamado GetLB. Considerando o contexto de transferência eletrônica de fundos (TEF), GetLB oferece uma nova forma de organizar as interações entre o chaveador e as máquinas processadoras. Esta organização permite que o chaveador combine informações atualizadas para a execução de um algoritmo de programação dinâmica em vez de usar a abordagem Round-Robin entre as máquinas de processamento. O algoritmo de agendamento de GetLB divide as transações em diferentes tipos, combinando suas necessidades de CPU, memória e disco de dados de máquinas processadoras para oferecer um balanceamento de carga eficiente. Implementou-se um protótipo com RMI e testes revelaram que o quadro é viável para processamento de transações sobre os ambientes homogêneos e heterogêneos. Além disso, a avaliação apresentou as vantagens da adoção de algoritmos GetLB em vez da abordagem Round-Robin tradicional.