Página 1 dos resultados de 2004 itens digitais encontrados em 0.065 segundos

Avaliação e predição de desempenho de programas paralelos em redes de estações de trabalho.; Parallel program performance analysis and prediction on NOW systems.

Li, Kuan Ching
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/10/2001 Português
Relevância na Pesquisa
55.73%
Processamento distribuído tem sido utilizado amplamente para melhorar o desempenho de aplicações com alta demanda computacional. Diferentes arquiteturas e topologias distribuídas têm sido pesquisadas e utilizadas para prover o alto desempenho, proporcionando assim o recurso necessário para a exploração do paralelismo presente nas aplicações. A facilidade para construir sistemas computacionais de alto desempenho a partir de estações de trabalho interligadas através de redes de alta velocidade, aliada ao custo relativamente baixo e ao crescente avanço da tecnologia de circuitos integrados, possibilita a montagem de redes de computadores de baixo custo para a execução de aplicações paralelas. Devido a este fato, diversos sistemas de software para redes de estações têm sido desenvolvidos, visando a integração dos componentes distribuídos para a agregação das suas capacidades de processamento. No entanto, o processo de desenvolvimento de aplicações é complexo e difícil, dado que são necessários identificar o paralelismo existente nestas aplicações, e providenciar as comunicações necessárias. Neste trabalho, é apresentada uma proposta de metodologia de análise e predição de desempenho de programas paralelos...

Sistemas de trabalho de alta performance: um estudo comparativo entre dois Esquadrões da Força Aérea Brasileira; High Performance Work Systems: a comparative study between Brazilian Air Force Squadrons

Rotter, Eveline Angélica Cunha
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/05/2010 Português
Relevância na Pesquisa
105.72%
Uma Equipe de Alta Performance é criada e sustentada, de acordo com os pressupostos teóricos expostos pelo presente trabalho, por um High Performance Work System (HPWS) ou, em português, Sistema de Trabalho de Alta Performance. Embora o termo em questão seja pesquisado há mais de cinco décadas por estudiosos de diversas áreas do conhecimento, sobretudo pela administração, seus conceitos ainda não são consensuais e, principalmente, há poucas observações em língua portuguesa. Paralelamente a esta questão, pode-se afirmar que uma constante busca por resultados organizacionais, sejam eles financeiros ou não, pelos agentes do mundo organizacional moderno é uma realidade. A proposta do presente trabalho centra-se em explorar ambos os conceitos relatados em duas organizações governamentais, o Esquadrão de Demonstração Aérea (EDA) e o Esquadrão Arara. Isso posto, primeiramente, é importante ressaltar que a pesquisa tem um cunho teórico, ao reunir o que estudiosos de diversas áreas têm descoberto e afirmado sobre o HPWS, relatando-os na língua portuguesa. Em segundo lugar, foi possível criar um quadro com os elementos organizacionais presentes em um HPWS, de acordo com as bibliografias pesquisadas. Com base nesse quadro selecionaram-se algumas características para fins de comparação nos dois Esquadrões. As características são: comprometimento...

Desenvolvimento de um sistema de controle para suspensões ativas de elevadores de alto desempenho; Development of a controller for an active suspension system for high performance elevators

Rivas López, Santiago Miguel
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
65.6%
O presente trabalho aborda o desenvolvimento de um algoritmo de controle para um sistema de suspensão ativa para elevadores de alto desempenho. Esses dispositivos são muito usados no caso de suspensões veículos automotivos, mas não tanto em elevadores. Visando compreender os fenômenos envolvidos e executar testes do controle proposto através de simulações, é realizado um estudo da modelagem matemática desse sistema. O elevador estudado é de cabine com duplo andar (double-deck) e será usado em uma guia de 200 [m] de curso em um edifício de aproximadamente 500 [m] de altura. A velocidade de estado estacionário do elevador é 40 km/h. Buscando situar este trabalho no campo de pesquisa proposto, é apresentada uma introdução aos critérios e técnicas de controle linear utilizadas. O desenvolvimento do controlador é baseado no uso de um modelo matemático linear em espaço de estados que representa a dinâmica do sistema em um dos planos ortogonais. A síntese do controlador por realimentação no espaço de estados foi feita usando o método da alocação de pólos, com ajuda do regulador quadrático linear, realimentando os estados com um observador de ordem total. Um modelo computacional foi construído e utilizado para a realização de simulações computacionais com o controlador proposto. Os resultados de simulações do sistema passivo e ativo são apresentados e discutidos.; The present work proposes the development of an algorithm to control active suspension systems for high performance elevators. These devices are used in suspensions for automotive vehicles...

Implementation Workshop: High Performance Work Organizations

Klein, Jan; Cutcher-Gershenfeld, Joel; Barrett, Betty
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Conferência ou Objeto de Conferência Formato: 109766 bytes; application/pdf
Português
Relevância na Pesquisa
75.54%
Since the rise of the industrial revolution, there are few challenges that compare in scale and scope with the challenge of implementing lean principles in order to achieve high performance work systems. This report summarize key insights and learning by representatives from a cross section of organizations who are on this journey. Specifically, we report on findings from the first Lean Aircraft Initiative (LAI) Implementation Workshop, which was held on February 5-6, 1997.

Implementation Workshop: High Performance Work Organizations

Klein, Jan; Cutcher-Gershenfeld, Joel; Barrett, Betty
Fonte: Masschusetts Institute of Technology Publicador: Masschusetts Institute of Technology
Tipo: Relatório Formato: 109766 bytes; application/pdf
Português
Relevância na Pesquisa
75.54%
Since the rise of the industrial revolution, there are few challenges that compare in scale and scope with the challenge of implementing lean principles in order to achieve high performance work systems. This report summarize key insights and learning by representatives from a cross section of organizations who are on this journey. Specifically, we report on findings from the first Lean Aircraft Initiative (LAI) Implementation Workshop, which was held on February 5-6, 1997. The report is not a “cookbook” or a “how to” manual. Rather, it is a summary of the first phase in a learning process. It is designed to codify lessons learning, facilitate diffusion among people not at the session, and set the stage for further learning about implementation.

Creating high performance enterprises

Stanke, Alexis K. (Alexis Kristen), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 216 p.
Português
Relevância na Pesquisa
65.73%
How do enterprises successfully conceive, design, deliver, and operate large-scale, engineered systems? These large-scale projects often involve high complexity, significant technical challenges, a large number of diverse stakeholders, distributed execution, and aggressive goals. In this context, simultaneously meeting technical performance, cost, and schedule goals effectively and efficiently is a serious challenge. In fact, it is rarely accomplished. The nature of an enterprise contributes to this challenge. Enterprises are interorganizational networks with distributed leadership and stakeholders with both common and diverse interests. They are unique from traditional levels of analysis in organizational studies, and in general their behavior is not well understood. They are a prevalent form of organizing work in these large engineering projects, where one organization simply does not have the capability or willingness to take on the entire project by themselves. This work explores the factors that distinguish high performance enterprises from those that are less successful in these large-scale projects. The setting for this research is programs in the aerospace industry.; (cont.) A comparative case study method was used to study nineteen programs spanning the U.S. (mainly defense) aerospace industry in order to develop grounded theory regarding contemporary program execution strategies and distinguishing attributes. Drawing on prior research with high performance teams...

Design of high performance RFID systems for metallic item identification.

Ng, Mun Leng
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008 Português
Relevância na Pesquisa
55.7%
Although the origins of Radio Frequency Identification (RFID) technology can be traced back for many years, it is only recently that RFID has experienced rapid growth. That growth is mainly due to the increasing application of this technology in various supply chains. The widening of the implementation of RFID technology in supply chains has posed many challenges and one of the biggest is the degradation of the RFID system performance when tagging metallic objects, or when the RFID system operates in a metallic environment. This thesis focuses on tackling the issue of having metallic objects in an Ultra High Frequency (UHF) RFID system. The work presented in this thesis contributes to the research on UHF RFID systems involving metallic objects in several ways: (a) the development of novel RFID tags that range from a simple tag for general applications to tags suitable for metallic object identification; (b) the tag designs target the criteria of minimal tag size and cost to embrace the vision of item level tagging; and (c) the analysis of the performance (through theoretical predictions and practical measurements) of an RFID tag near metallic structures of various shapes and sizes. The early part of this thesis provides a brief introduction to RFID and reviews the background information related to metallic object identification for UHF RFID systems. The process of designing a basic tag...

High performance RF CMOS VCOs for wireless communication.

Kim, Tae Youn
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2005 Português
Relevância na Pesquisa
55.6%
This thesis is dedicated to develop a set of general and systematic techniques to design and produce high performance monolithic CMOS VCOs to use in modem wireless front-end chips. In general, there are four topics covered in this research work. First, existing oscillator phase noise estimation theories are discussed. Some of these theories lead to simple and rough estimation of the phase noise, while some forms the basis for more complicated and accurate phase noise estimation performed by modem CAD tools. Second, the operation and noise performance of a number of differential LC tuned VCO topologies are investigated in detail. Some common misconceptions associated with cross-coupled oscillators, including the incorrect linear oscillation amplitude expressions, nonexistence of a VCO bias region called voltage-limited region, and the non-apparent topological advantage of the complementary topology are addressed. AIso the noise sources associated with differential LC tuned VCOs are identified and investigated. Upconversion processes of low frequency flicker noise through various up conversion processes are discussed. Third, based on the understandings acquired from the differential Le tuned oscillator analyses, a set of new optimization techniques is developed. These techniques allow for design of the best performing VCO realizable for a given process technology...

State observers and Kalman filtering for high performance vibration isolation systems

Beker, M. G.; Bertolini, A.; van den Brand, J. F. J.; Bulten, H. J.; Hennes, E.; Rabeling, D. S.
Fonte: American Institute of Physics (AIP) Publicador: American Institute of Physics (AIP)
Tipo: Artigo de Revista Científica Formato: 12 pages
Português
Relevância na Pesquisa
55.61%
There is a strong scientific case for the study of gravitational waves at or below the lower end of current detection bands. To take advantage of this scientific benefit, future generations of ground based gravitational wave detectors will need to expand the limit of their detection bands towards lower frequencies. Seismic motion presents a major challenge at these frequencies and vibration isolation systems will play a crucial role in achieving the desired low-frequency sensitivity. A compact vibration isolation system designed to isolate in-vacuum optical benches for Advanced Virgo will be introduced and measurements on this system are used to present its performance. All high performance isolation systems employ an active feedback control system to reduce the residual motion of their suspended payloads. The development of novel control schemes is needed to improve the performance beyond what is currently feasible. Here, we present a multi-channel feedback approach that is novel to the field. It utilizes a linear quadratic regulator in combination with a Kalman state observer and is shown to provide effective suppression of residual motion of the suspended payload. The application of state observer based feedback control for vibration isolation will be demonstrated with measurement results from the Advanced Virgo optical bench suspension system.; This work is part of the research program of the Foundation for Fundamental Research on Matter (FOM)...

Improving High Performance Networking Technologies for Data Center Clusters

Grant, RYAN
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
65.67%
This dissertation demonstrates new methods for increasing the performance and scalability of high performance networking technologies for use in clustered computing systems, concentrating on Ethernet/High-Speed networking convergence. The motivation behind the improvement of high performance networking technologies and their importance to the viability of modern data centers is discussed first. It then introduces the concepts of high performance networking in a commercial data center context as well as high performance computing (HPC) and describes some of the most important challenges facing such networks in the future. It reviews current relevant literature and discusses problems that are not yet solved. Through a study of existing high performance networks, the most promising features for future networks are identified. Sockets Direct Protocol (SDP) is shown to have unexpected performance issues for commercial applications, due to inefficiencies in handling large numbers of simultaneous connections. The first SDP over eXtended Reliable Connections implementation is developed to reduce connection management overhead, demonstrating that performance issues are related to protocol overhead at the SDP level. Datagram offloading for IP over InfiniBand (IPoIB) is found to work well. In the first work of its kind...

Preditores organizacionais do engagement no trabalho: o papel das práticas de recursos humanos de elevado desempenho e do clima sociomoral

Jacinto, Ana Isabel André
Fonte: Instituto Universitário de Lisboa Publicador: Instituto Universitário de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
Relevância na Pesquisa
85.71%
Dissertação submetida como requisito parcial para obtenção do grau de Mestre em Psicologia Social e das Organizações; A presente investigação teve como objetivo principal contribuir para uma melhor compreensão do papel das práticas de recursos humanos de elevado desempenho (PRHED) e do clima sociomoral enquanto preditores organizacionais do engagement no trabalho. Através de uma amostra com 181 indivíduos que trabalham em contexto organizacional em diferentes organizações e setores de atividade, procurou-se analisar o papel das práticas de recursos humanos de elevado desempenho (PRHED) organizadas de acordo com duas configurações - PRHED individuais e sistema PRHED - na predição dos níveis de engagement dos trabalhadores, e o papel do clima sociomoral nesta relação nomeadamente na mediação entre as PRHED e o engagament. Os resultados permitiram-nos concluir, numa primeira fase, que as PRHED nas suas diferentes configurações predizem positiva e significativamente os níveis de engagement, bem como são importantes preditores de um clima sociomoral positivo. Numa segunda fase, o clima sociomoral mostrou-se positivamente associado aos níveis de engagement e revelou-se um importante mediador entre as PRHED e o engagement. As análises efetuadas permitiram-nos concluir que para além das configurações mais adequadas...

Managing talent through developmental job experiences (DJE): The mediating role of DJE between HPWS and employees' outcomes

Canha, Raquel Sofia Sebastião
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /01/2015 Português
Relevância na Pesquisa
85.67%
In the competitive landscape of the 21st century, effectively managing human capital in firms is considered to be a potential source of sustainable performance. Therefore, in this study, we tested the influence of high-performance work systems, as a talent management tool, on employees’ experience of developmental jobs. Then, we tested the mediating effect of such experiences on employees’ engagement, exhaustion, performance and turnover intention. With a sample of 254 employees of a diversity of companies and sectors of activity, our findings demonstrated that high-performance practices increase engagement, via the promotion of developmental experiences of fit, which improves performance and decreases turnover intention. Besides, those practices do not control for the pressure dimension of the developmental job experiences that increases exhaustion and turnover intention despite not worsening performance.

Influence of High Performance Work Systems on Employee Subjective Well-being and Job Burnout: Empirical Evidence from the Chinese Healthcare Sector

Fan, Di; Cui, Lin; Zhang, Mike Mingqiong; Zhu, Jiuhua (Cherrie); Hartel, Charmine E.J.; Nyland, Chris
Fonte: Routledge, Taylor & Francis Group Publicador: Routledge, Taylor & Francis Group
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
85.63%
Over the last two decades, high performance work systems (HPWSs) research has been dominated by examining the effects of these systems on firm performance. Research on the impact of HPWSs on employees has been marginalised. This study examines the impact

Efficient HTTP based I/O on very large datasets for high performance computing with the libdavix library

Devresse, Adrien; Furano, Fabrizio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/10/2014 Português
Relevância na Pesquisa
55.6%
Remote data access for data analysis in high performance computing is commonly done with specialized data access protocols and storage systems. These protocols are highly optimized for high throughput on very large datasets, multi-streams, high availability, low latency and efficient parallel I/O. The purpose of this paper is to describe how we have adapted a generic protocol, the Hyper Text Transport Protocol (HTTP) to make it a competitive alternative for high performance I/O and data analysis applications in a global computing grid: the Worldwide LHC Computing Grid. In this work, we first analyze the design differences between the HTTP protocol and the most common high performance I/O protocols, pointing out the main performance weaknesses of HTTP. Then, we describe in detail how we solved these issues. Our solutions have been implemented in a toolkit called davix, available through several recent Linux distributions. Finally, we describe the results of our benchmarks where we compare the performance of davix against a HPC specific protocol for a data analysis use case.; Comment: Presented at: Very large Data Bases (VLDB) 2014, Hangzhou

Mathematical modeling of thermal stabilization of vertical wells on high performance computing systems

Pavlova, Natalia V.; Vabishchevich, Petr N.; Vasilyeva, Maria V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/04/2013 Português
Relevância na Pesquisa
65.54%
Temperature stabilization of oil and gas wells is used to ensure stability and prevent deformation of a subgrade estuary zone. In this work, we consider the numerical simulation of thermal stabilization using vertical seasonal freezing columns. A mathematical model of such problems is described by a time-dependent temperature equation with phase transitions from water to ice. The resulting equation is a standard nonlinear parabolic equation. Numerical implementation is based on the finite element method using the package Fenics. After standard purely implicit approximation in time and simple linearization, we obtain a system of linear algebraic equations. Because the size of freezing columns are substantially less than the size of the modeled area, we obtain mesh refinement near columns. Due to this, we get a large system of equations which are solved using high performance computing systems.; Comment: 9 pages, 5 figures

A distributed file system for a wide-area high performance computing infrastructure

Walker, Edward
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/12/2009 Português
Relevância na Pesquisa
65.58%
We describe our work in implementing a wide-area distributed file system for the NSF TeraGrid. The system, called XUFS, allows private distributed name spaces to be created for transparent access to personal files across over 9000 computer nodes. XUFS builds on many principles from prior distributed file systems research, but extends key design goals to support the workflow of computational science researchers. Specifically, XUFS supports file access from the desktop to the wide-area network seamlessly, survives transient disconnected operations robustly, and demonstrates comparable or better throughput than some current high performance file systems on the wide-area network.; Comment: 6 pages, Proceedings of Third USENIX Workshop on Real, Large Distributed Systems, Seattle, Nov 2006

A Theoretical and Computational Study of Limit Cycle Oscillations in High Performance Aircraft

Padmanabhan, Madhusudan A.
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2015 Português
Relevância na Pesquisa
65.62%

High performance fighter aircraft such as the F-16 experience aeroelastic Limit Cycle Oscillations (LCO) when they carry certain combinations of under-wing stores. This `store-induced LCO' causes serious problems including airframe fatigue, pilot discomfort and loss of operational effectiveness. The usual response has been to restrict the stores carriage envelope based on flight test experience, and accept the accompanying reduction in mission performance.

Although several nonlinear mechanisms - structural as well as aerodynamic, have been proposed to explain the LCO phenomenon, their roles are not well understood. Consequently, existing models are unable to predict accurately AND reliably the most critical LCO properties, namely onset speed and response level. On the other hand, the more accurate Computational Fluid Dynamics (CFD) based time marching methodology yields results at much greater expense and time. Clearly, there is a critical need to establish methods that are more rapid while providing accurate predictions more in line with flight test results than at present. Such a capability will also aid in future aircraft design and usage.

This work was undertaken to develop a better understanding of nonlinear aeroelastic phenomena...

Control of high-performance mini- and microscale electrical cylinders

Lyshevski, Sergey
Fonte: IEEE Publicador: IEEE
Tipo: Proceedings
Português
Relevância na Pesquisa
55.64%
The focus of this paper is the application of mini and microscale electrical cylinders as high-performance translational actuators that guarantee fast and precise positioning. The objectives are to design, analyze, test and compare different control algorithms for closed-loop electrical cylinders with permanent-magnet direct current and synchronous servomotors. These electrical cylinders are widely used in aerospace, automotive, robotics and other electromechanical systems. For example, electrical cylinders displace the control surfaces of flight and undersea vehicles, robotic arms, etc. The major emphases are placed in the analysis and design of affordable, robust, efficient, and high torque density servos. Electrical cylinders with different servomotors are tested in order to examine alternative solutions. The performance comparison is made for electrical cylinders regulated using distinct controllers. These control laws are designed and implemented using advanced DSP, microcontrollers and VLSI controllers-drivers. We synthesize proportional-integral-derivative (PID), nonlinear, relay, and sliding mode controllers to guarantee the optimal (achievable) dynamic performance, stability, robustness, accuracy, etc. For different commands (angular or linear position and acceleration) and loads...

Unions and productivity, financial performance and investment: international evidence

Metcalf, David
Fonte: Centre for Economic Performance, London School of Economics and Political Science Publicador: Centre for Economic Performance, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /07/2002 Português
Relevância na Pesquisa
65.54%
If the presence of a union in a workplace or firm raises the pay level, unless productivity rises correspondingly, financial performance is likely to be worse. If the product market is uncompetitive this might imply a simple transfer from capital to labour with no efficiency effects, but is probably more likely to lead to lower investment rates and economic senescence. Therefore the impact of unions on productivity, financial performance and investment is extremely important. This paper distils evidence on such effects from six countries: USA, Canada, UK, Germany, Japan and Australia. It is not possible to use theory to predict unambiguously any union effect on productivity because unions can both enhance and detract from the productivity performance of the workplace or firm. The evidence indicates that, in the USA, workplaces with both high performance work systems and union recognition have higher labour productivity than other workplaces. In the UK previous negative links between unions and labour productivity have been eroded by greater competition and more emphasis on ''partnership'' in industrial relations but there is a lingering negative effect of multi-unionism, just as there is in Australia. In Germany the weight of the evidence suggests that the information...

The future of the German industrial relations model

Marsden, David
Fonte: Centre for Economic Performance, London School of Economics and Political Science Publicador: Centre for Economic Performance, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /03/2015 Português
Relevância na Pesquisa
55.66%
The paper examines recent evidence on the erosion of the German industrial relations model. Although its coverage has declined, much of this has occurred in smaller and newer establishments, and compared with Britain, it has remained solid in the areas of Germany's traditional industrial strength. This is explained by the nature of high performance work systems that involve flexible working and on-the-job problem-solving. Both countries have modernised their work systems in recent decades, with German industrial firms maintaining higher degrees of worker autonomy and learning and British ones relying more on managerial control. The survival of the German model in this sector, as compared with services, is attributed to the role of such work systems in the high end of international competition. A model is developed to explain why stable cooperation within these work relationships is enhanced by means of a strong institutional framework. It is then used to explain why employers in the sectors using these systems have continued to work within these institutions. It is argued that employers’ increased focus on the match between commercial needs and workplace institutions has contributed to the growing segmentation within German industrial relations which has been widely documented...