Luis Hideo Vasconcelos Nakamura
University of São Paulo
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Featured researches published by Luis Hideo Vasconcelos Nakamura.
PLOS ONE | 2015
Bruno Guazzelli Batista; Júlio Cezar Estrella; Carlos H. G. Ferreira; Dionisio Machado Leite Filho; Luis Hideo Vasconcelos Nakamura; Stephan Reiff-Marganiec; Marcos José Santana; Regina Helena Carlucci Santana
Cloud computing is a computational model in which resource providers can offer on-demand services to clients in a transparent way. However, to be able to guarantee quality of service without limiting the number of accepted requests, providers must be able to dynamically manage the available resources so that they can be optimized. This dynamic resource management is not a trivial task, since it involves meeting several challenges related to workload modeling, virtualization, performance modeling, deployment and monitoring of applications on virtualized resources. This paper carries out a performance evaluation of a module for resource management in a cloud environment that includes handling available resources during execution time and ensuring the quality of service defined in the service level agreement. An analysis was conducted of different resource configurations to define which dimension of resource scaling has a real influence on client requests. The results were used to model and implement a simulated cloud system, in which the allocated resource can be changed on-the-fly, with a corresponding change in price. In this way, the proposed module seeks to satisfy both the client by ensuring quality of service, and the provider by ensuring the best use of resources at a fair price.
international symposium on computers and communications | 2014
Ariel da Silva Dias; Luis Hideo Vasconcelos Nakamura; Júlio Cezar Estrella; Regina Helena Carlucci Santana; Marcos José Santana
A cloud computing infrastructure management is proposed in this paper, which consists of two approaches that facilitate the provisioning of computing resources in a self-adaptive virtualized environment. Resource allocation is employed to predict the future of workload management and to employ a self-adaptive approach by using computational agents to monitor the Virtual Machines (VMs). The paper also includes the Return on Investment (ROI) formula that deals with the relationship between the prices for the Infrastructure-as-a-Service (IaaS) contracted by the customer and the effective use of this service. The experimental results show a significant improvement when self-configuration is used with agent-based computational modeling in contrast with the self-configuration based on prediction for future workload.
distributed computing in sensor systems | 2015
Diulie J. Freitas; Tiago B. Marcondes; Luis Hideo Vasconcelos Nakamura; Rodolfo Ipolito Meneguette
Health Smart Home (HSH) provides health care services for people with special needs and wish to be independent and remain in their own home. The residence is equipped with automatic devices and a range of sensors to ensure the safety of the patients at home and the supervision of their health status. These Health Smart Homes have been increasingly studied not only by the academic community but also by industry on account of the great potential it has, especially in applications that can help people with some type of physical disability such as visual or hearing impairment. We implemented a system witch monitors rooms and issues a warning whenever it detects a potential hazard. Our proposal relies on low-cost cutting-edge technology.
international conference on web services | 2014
Luiz Henrique Nunes; Luis Hideo Vasconcelos Nakamura; Bruno Tardiole Kuehne; Edvard Martins de Oliveira; Rafael Mira De Oliveira Libardi; Lucas Junqueira Adami; Júlio Cezar Estrella; Stephan Reiff-Marganiec
Performing functionality testing in service-oriented architectures is not a trivial task. The difficulty is especially the large number of components that may be present in a SOA such as brokers, providers, service registries, clients, monitoring tools, data storage tools, etc. Thus, in order to facilitate the process of conducting functional testing and capacity planning in service-oriented systems, we present PEESOS. This first version is a functional prototype that offers facilities to assist researchers and industry to test their new applications, allowing collaborations that can be done between the participants to achieve an appropriate objective when developing a new application. The first results show that it is possible to make a planning environment easier to operate and to readily obtain results for performance evaluation of a target architecture. Since this is a first version of the prototype, it has interface and scalability limitations as well as needing improvements in performance of the logs repository and also in a core engine. We hope that such limitations can be corrected in the near future, including gathering information from the scientific community to make the prototype a useful and accessible tool. PEESOS is on-line and available at http://peesos.wsarch.lasdpc.icmc.usp.br.
international conference on web services | 2014
Luiz Henrique Nunes; Luis Hideo Vasconcelos Nakamura; Heitor de Freitas Vieira; Rafael Mira De Oliveira Libardi; Edvard Martins de Oliveira; Lucas Junqueira Adami; Júlio Cezar Estrella; Stephan Reiff-Marganiec
This paper analyzes the execution behavior of web services on devices with limited resources. The experiments compare web services in the Axis2 and CXF frameworks analyzing performance and power consumption. To determine which framework is better suited for service provision, a testing environment and a performance and energy evaluation between them are presented. We show that the Raspberry Pi can be useful in service-oriented applications for different types of tasks. Bringing together the best features of small devices and SoC, it is possible to provide diverse, mobile and green applications.
conference on network and service management | 2014
Edvard Martins de Oliveira; Júlio Cezar Estrella; Bruno Tardiole Kuehne; Dionisio Machado Leite Filho; Lucas Junqueira Adami; Luiz Henrique Nunes; Luis Hideo Vasconcelos Nakamura; Rafael Mira De Oliveira Libardi; Paulo Sergio Lopes de Souza; Stephan Reiff-Marganiec
Fault tolerance techniques can improve the trust of users in service oriented architectures as they can ensure data availability. This paper presents an implementation of a novel fault tolerance mechanism in a SOA architecture which simultaneously provides increased availability and better quality of service. In addition to this mechanism, a service selector using reputation ratings of the architecture components is discussed. The selection is based on information from past transactions of the components of the architecture, which allows to identify the best web services able to meet the requests of customers. The mechanisms are tested and a performance evaluation is presented to validate the results.
new technologies, mobility and security | 2015
Diulie J. Freitas; Tiago B. Marcondes; Luis Hideo Vasconcelos Nakamura; Jo Ueyama; Pedro Henrique Gomes; Rodolfo Ipolito Meneguette
Smart homes provide automatic services through a combination of wireless sensor networks (WSNs) and wireless devices that allow monitoring operations in the home. These smart homes have been increasingly studied not only by the academic community but also by industry on account of the great potential they have, especially in applications that can help people with some type of physical disability such as visual or hearing impairment. This kind of application can give them independence and make their lives safer and more comfortable. Thus, in this paper we propose a Health Smart Home system for disabled people that can warn them about possible accidents that can occur in a particular location of their house. In other words, the system anticipates possible accidents that may occur somewhere in the house. We implemented a preliminary prototype that monitors rooms and issues a warning whenever it detects a potential hazard. Our proposal relies on low-cost cutting-edge technology and includes the following: Raspberry Pi boards, motion sensors, cameras and a central server. The server will handle the data that has been captured by sensors and send warnings through smartphones to people with physical impairments.
conference on network and service management | 2014
Luis Hideo Vasconcelos Nakamura; Júlio Cezar Estrella; Regina Helena Carlucci Santana; Marcos José Santana; Stephan Reiff-Marganiec
This paper presents a semantic approach to custom management of IaaS (Infrastructure as a Service) resources in a cloud computing environment requiring minimal human intervention from both the cloud provider and the user. The proposal differs from other approaches by using autonomic computing and semantic web techniques together to provide a self-configuring and self-optimizing environment that aims to satisfy SLAs (Service Level Agreements). The approach monitors the virtualized resources to guarantee a customized and optimized use based on financial criteria and energy consumption policies.
2012 13th Symposium on Computer Systems | 2012
Pedro Felipe do Prado; Luis Hideo Vasconcelos Nakamura; Júlio Cezar Estrella; Marcos José Santana; Regina Helena Carlucci Santana
In this paper four different algorithms are proposed to solve the QoS-aware Web Services Composition (QWSC) problem in six different search-space sizes and a realistic deadline (a point not covered in many related works). Differently from some related works, statistical techniques are adopted in this paper in order to ensure more precise results from the algorithms. Two new algorithms are proposed: Greedy Heuristic and Double Hybrid Genetic Algorithm. The results of these algorithms were compared with an Exhaustive Search algorithm that always guarantees the global optima and a heuristic algorithm called Utility Function. The results obtained showed that the design of experiments and the performance evaluation can be used to determine which algorithms has better performance according to the different search-space sizes and the established deadline, it is also possible to determine which genetic operators are better suited for the QWSC problem.
2011 Simpasio em Sistemas Computacionais | 2011
Luis Hideo Vasconcelos Nakamura; Júlio Cezar Estrella; Marcos José Santana; Regina Helena Carlucci Santana
This paper presents a study on the use of Semantic Web and Ontology created with the OWL (Web Ontology Language) to sort and select Web Services according to its Quality of Service (QoS) attributes. The focus of this paper is to evaluate the performance of this approach in accordance with some adopted parameters. To this end, two algorithms that use Semantic Web resources have been developed in order to make the discovery of appropriate Web Services in the ontology. At the end of this article, the results of a performance evaluation are presented and analyzed.