Sarita Mazzini Bruschi

Performance evaluation based on system modeling using Statecharts extensions

Abstract This paper presents two extensions for Statecharts: the Stochastic Statecharts, which use the original statecharts notation with a minor modification in the formal semantics and the Queuing Statecharts, which do not follow the pure Statecharts notation, but a join between Statecharts and queuing network representations. Some basic elements of Statecharts are redefined such as events and conditions, besides some concepts referring to the dynamic system behavior. The specification approaches show the basic behavior of a generic queuing system by means of templates and standard events. It is presented the PerformCharts, a new simulation environment based on Statecharts specification, which allows model solution using either Markov chains or the Network Simulator (NS).

An automatic distributed simulation environment

Developing a sequential simulation program is not an easy task. Developing a distributed simulation program is harder than a sequential one because it is necessary to deal with mapping physical processes into logical processes, communication and synchronization problems and learn another simulation language/library. In the literature, several simulation environments can be found but the great number are for sequential simulation, not using all the advantages of a distributed/parallel platform. This paper presents ASDA, an automatic distributed simulation environment that aims at providing several possibilities to users developing a distributed simulation. The automatic word can be understood in three different ways: the environment automatically generates a distributed simulation program code; the environment can automatically choose one distributed simulation approach; and the environment can automatically convert a sequential simulation program into a distributed simulation program using the MRIP (multiple replication in parallel) approach.

A Performance Evaluation Study for Web Services Attachments

Web Services are a technology based on the Service Oriented Architecture that enables communication between applications through the Internet. Using Web Services, it is possible to send any type of information in any form of encryption. In this context, different techniques have been used to attach binary files in SOAP messages. However, there is no consensus on which technique has the best performance. This paper presents a performance evaluation study with three techniques for Web Service attachments: Pure Binary, MTOM and SwA. A testing environment was configured to verify the influence of the network and the size of files. Also, we present a tool called WSATPerf that supports the execution of the performance evaluation.

PIV and WPIV: Performance Index For Heterogeneous Systems Evaluation

This article presents two new performance indices (PIV - performance index vector and WPIV - weighted performance index vector), to evaluate heterogeneous computing systems, based on a Euclidian metric. Aiming to maximize the use of the machines, the proposed indices are a combination of several usual indices and the results of their evaluation through a simulator show an appropriate behavior for different kinds of applications

A Performance Evaluation for a QoS-Aware Service Oriented Architecture

Web services have emerged as a technology that aims at improving the communication between applications, through the service-oriented paradigm. Researches involving web semantics, ontology and composition of services has currently been developed. However, research in performance evaluating of web services architecture with quality of service support (QoS) is little widespread. Some works separately approach techniques as composition of Web services and models of architectures to improve the quality of Web services. Considering the lack of work involving jointly these different boarding, the purpose of this work is show a performance evaluating of a prototype architecture named WSARCH (Web Services Architecture) that relating quality of service attributes. The initial prototype of the architecture already allows investigate new ways of evaluating performance of Web services based on a contract model and improved existing service discovery solution though the incorporation of quality-of-service issues and related metrics for ranking matches.

Performance evaluation of a CMB protocol

This paper presents the performance evaluation of a CMB (Chandy-Misra-Bryant) protocol from the perspective of execution time. The performance of each logical process in simulation is measured. Our evaluation shows that logical processes can have different behaviors and different protocols can be used simultaneously in simulations. While some logical processes may perform well using conservative protocols, others can use optimistic protocols because otherwise most of the time these processes would be blocked unnecessarily. In order to analyze the behavior of the simulations some models were simulated using a CMB implementation called ParSMPLX. These models showed that each logical process of a simulation has a different behavior that makes it more suitable for a specific protocol, increasing the performance

Green Cloud Meta-Scheduling

This article aims to evaluate the flexibility of GreenMACC (Metascheduling Green Architecture to Provide Quality of Service in Cloud Computing). The GreenMACC has a module called LRAM (Local Resource Allocation Manager) to automate the execution of all scheduling policies implemented in the architecture. This module enables the Meta-scheduler automatically adjust for each type of service requested by the user of a private cloud. Due to this function, can be ensure the most appropriate behavior to the principles of GreenIT while worrying about the quality of service. In this paper is shown the importance of the LRAM on GreenMACC. This article is also shown how to include a new policy in GreenMACC in a way that identifies the LRAM and automatically use. Through the performance evaluation of the new policy included it could be concluded that the GreenMACC is a flexible, reliable architecture and the LRAM module enables the automation of choosing the best scheduling mechanism in a private cloud.

WSBCL: Web Services Based Classloader

This paper presents a model, implementation and performance evaluation of a class loader for Java Platform entirely based on web services (WSBCL). Designed to address the needs of desktop grid computing middle wares, WSBCL can be integrated and used by any Java solution for distributed systems. This class loader allows low computational power devices to act in the role of class repository without the installation of conventional servers. The model allows devices located behind firewalls and NATs to act as class servers answering external requests.

Providing Computing Services through Mobile Devices in a Collaborative Way - A Fog Computing Case Study

The increasing number of mobile devices, such as smartphones, tablets and laptops, and also advances in their computing power enabled them to be considered as computing resources, having their proximity explored. The use of nearby resources for computing is growing year by year and it is called Fog Computing. The elements on the edge of the Internet are exploited once the computer service providers could be unavailable or overloaded. This work focuses on using mobile devices to provide computing services by using an heuristic called Adapted Maximum Regret, which tries to minimize energy and avoid unreliable devices. There is also a top-level meta-heuristic which has global information and interconnects different clusters of devices on the edge of the Internet to guarantee QoS. We conducted a set of experiments that demonstrated we should avoid devices with a high degree of failures to save more energy when allocating tasks as well as to decrease the applications response time and communication through adjustments in the selection algorithm of external agglomerates.

A Suite of Java Message-passing Benchmarks to Support the Validation of Testing Models, Criteria and Tools

This paper proposes a novel suite of benchmarks for the evaluation of the structural testing of concurrent programs with message-passing paradigm. This suite is composed of thirteen bug-free programs and five faulty programs. The benchmarks are developed in Java and are available as free-software on the Internet. They were validated with experimental studies and also have been used in different research and for educational aims. The obtained results showed that the benchmarks can generate qualified workload for the testing of message-passing programs. The main contribution of this study is the development of a more robust and fair suite of benchmarks capable of improving the evaluation of the testing activity applied to concurrent programs.