Página 1 dos resultados de 21 itens digitais encontrados em 0.019 segundos

‣ Sensorless synchronization method for thin-film direct optical broadband monitoring system

MARTINS, A. L.; RODRIGUES, E. L. L.
Fonte: IOP PUBLISHING LTD Publicador: IOP PUBLISHING LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
67.76619%
Optical monitoring systems are necessary to manufacture multilayer thin-film optical filters with low tolerance on spectrum specification. Furthermore, to have better accuracy on the measurement of film thickness, direct monitoring is a must. Direct monitoring implies acquiring spectrum data from the optical component undergoing the film deposition itself, in real time. In making film depositions on surfaces of optical components, the high vacuum evaporator chamber is the most popular equipment. Inside the evaporator, at the top of the chamber, there is a metallic support with several holes where the optical components are assembled. This metallic support has rotary motion to promote film homogenization. To acquire a measurement of the spectrum of the film in deposition, it is necessary to pass a light beam through a glass witness undergoing the film deposition process, and collect a sample of the light beam using a spectrometer. As both the light beam and the light collector are stationary, a synchronization system is required to identify the moment at which the optical component passes through the light beam.

‣ Implementação de um cluster de computadores e desenvolvimento de seu sistema de gerenciamento; A computer cluster implementation and development of its management system

Tanaka, Fernando Yuichi
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 29/11/2004 Português
Relevância na Pesquisa
27.61105%
Nos últimos anos, clusters de computadores vêm ganhando popularidade, principalmente nos meios corporativos e académicos, como servidores Web, Isso se deve, principalmente, por eles oferecerem um custo/benefício bastante atraente. No entanto, esses clusters (conhecidos como Web Farms) possuem uma maior complexidade de gerenciamento e, principalmente os clusters de alta disponibilidade, necessitam de um monitoramento intensivo para manter os seus serviços sempre disponíveis. Este trabalho apresenta a implementação de um Web Farm Cluster e o desenvolvimento de um sistema de monitoramento e controle desse tipo de cluster (iCluster) utilizando a tecnologia de agentes de software. O sistema utiliza a tecnologia de agentes de software para implementar módulos de computação autónoma, permitindo dessa forma o monitoramento, o controle e a visualização de estados e serviços de um Web Farm Cluster com o mínimo de intervenção humana.; Recently, clusters of computers are gaining popularity, especially among corporations and universities, as Web servers. This happens, mainly, because they offer a very attractive cost/benefit ratio. However, these clusters (known as Web Farms) are more complex, difficult to manage and, in the case of high available systems...

‣ Calibration and performance of the tile calorimeter of ATLAS with cosmic ray muons

Saraiva, João Gentil Mendes, 1972-
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Tese de Doutorado
Publicado em //2010 Português
Relevância na Pesquisa
38.226096%
Tese de doutoramento, Física, Universidade de Lisboa, Faculdade de Ciências, 2011; The installation of the ATLAS detector in the experimental cavern, took place from 2005 until 2009. During this period, technicians, engineers and physicists have been intensivelyworking on the preparation of the detector for its main objective: probing the new frontiers of high energy physics with the LHC, the particle collider with the largest center of mass energy (14 TeV nominal) and very high luminosities(1034cm−2s−1 nominal). The context of this thesis was this challenging environment that involved all ATLAS members in the preparation of the detector for collisions during the period of the detector commissioning with cosmic ray muons and with calibration and monitoring systems. In 2008 during a short period of time single beam data was available and was used to study the detector response. This large effort was fundamental to prepare the detector for the first collisions at the LHC that started in November 2009. Before collisions started, the only high energy particles available for studieswith the LHC detectors were the muons produced by the interaction of cosmic particles in the atmosphere. These cosmic ray muons are the only detectable particles reaching the earth surface in quantities large enough to study the performance of the different sub-systems of the ATLAS detector. Thework I have developed duringmy PhDand thatwill be detailed in this document is centered on the energy calibration and synchronization of the Tile Calorimeter...

‣ Interactive Effects of Three Core Goal Pursuit Processes on Brain Control Systems: Goal Maintenance, Performance Monitoring, and Response Inhibition

Berkman, Elliot T.; Falk, Emily B.; Lieberman, Matthew D.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 29/06/2012 Português
Relevância na Pesquisa
27.78672%
Goal attainment relies in part on one’s ability to maintain a cognitive representation of the desired goal (goal maintenance), monitor the current state vis-à-vis the targeted end state and remain vigilant for lapses in progress (performance monitoring), and inhibit counter-goal behaviors (response inhibition). Because neurocognitive studies have typically examined these three processes in isolation from one another, little is known regarding if and how they interact during goal pursuit. However, these processes frequently co-occur during online, real-world goal pursuit. The present study employed a novel task to investigate how goal maintenance, performance monitoring, and response inhibition interact with one another. We identified functional activations distinct to each of the processes that correspond to results of prior investigations. In addition, we report interactive effects between response inhibition and goal maintenance in the dorsal anterior cingulate cortex and between performance monitoring and goal maintenance in the superior frontal gyrus and supramarginal gyrus. Implications for studying the neural systems of in situ goals include the need for both experimental designs that distinguish between process, but also more complex...

‣ Online Failure Prediction in Air Traffic Control Systems

Montanari, Luca
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
48.746855%
This thesis introduces a novel approach to online failure prediction for mission critical distributed systems that has the distinctive features to be black-box, non-intrusive and online. The approach combines Complex Event Processing (CEP) and Hidden Markov Models (HMM) so as to analyze symptoms of failures that might occur in the form of anomalous conditions of performance metrics identified for such purpose. The thesis presents an architecture named CASPER, based on CEP and HMM, that relies on sniffed information from the communication network of a mission critical system, only, for predicting anomalies that can lead to software failures. An instance of Casper has been implemented, trained and tuned to monitor a real Air Traffic Control (ATC) system developed by Selex ES, a Finmeccanica Company. An extensive experimental evaluation of CASPER is presented. The obtained results show (i) a very low percentage of false positives over both normal and under stress conditions, and (ii) a sufficiently high failure prediction time that allows the system to apply appropriate recovery procedures.

‣ The rapid atmospheric monitoring system of the Pierre Auger Observatory

Barber, K.; Bellido Caceres, J.; Clay, R.; Cooper, M.; Dawson, B.; Harrison, T.; Herve, A.; Holmes, V.; Sorokin, J.; Wahrlich, P.; Whelan, B.
Fonte: Institute of Physics Publishing Ltd Publicador: Institute of Physics Publishing Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
67.784976%
The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10^17 eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e.g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest...

‣ Cost as an independent variable (CAIV): front-end approaches to achieve reduction in total ownership cost

Boudreau, Michael
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório Formato: vi, 33 p.: ill.;28 cm.
Português
Relevância na Pesquisa
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Acquisition research (Graduate School of Business & Public Policy); Over several years, the United States General Accounting Office (now renamed the Government Accountability Office) reported private sector best practices for controlling costs and pointedly made comparisons with DoD acquisitions. In responding to GAO suggestions for improvement, DoD said the improvements would be forthcoming with the publication of new policy guidance. The new policy directives were published, beginning in May 2003. The final piece -- the Defense Acquisition Guidebook that recommends process and practice -- was put online in the fall of 2004. Now it is possible to address the operative question: Has the DoD put into place policy and implementing guidance, to practice CAIV in the acquisition of DoD's warfighting systems? Secondarily, has DoD established the processes and tools to monitor and control CAIV? Additionally, has the DoD leadership exhibited the will and determination to control Total Ownership Costs of its warfighting systems? Has the TOC focus changed?

‣ Advances in artificial intelligence to model student-centred VLEs

Alves, Paulo
Fonte: INTECH Publicador: INTECH
Tipo: Parte de Livro
Português
Relevância na Pesquisa
27.903652%
The challenges to the educational paradigm, introduced with the change from a teacher to a student centred paradigm, has several implications in the organization of all the educational system. The adoption of e-learning in all of the educational levels, was a huge step forward in terms of access to resources without constrains of space and time. But e-learning didn’t reach the plato in lifelong learning scenarios, because we have a great diversity of learning contexts in universities, with more students come back to update their knowledge when they are already in the work market. The paradigm “one size fits all” is still being applied and all the pedagogical approaches adopt the traditional lecturer centred paradigm. Student centred learning is an educational paradigm that gives students greater autonomy and control over choice of subject matter, learning methods and pace of study (Gibbs, 1992). This approach is very similar to the Bologna Process goals in terms of student centred model based on learning outcomes and competences. Some of the characteristics of effective learners in the student centred learning paradigm are (de la Harpe et al., 1999): • Have clear learning goals; • Have a wide repertoire of learning strategies and know when to use them; • Use available resources effectively; • Know about their strengths and weaknesses; • Understand the learning process; • Deal appropriately with their feelings; • Take responsibility for their own learning; • Plan...

‣ The rapid atmospheric monitoring system of the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, Ivone Freire da Mota e; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; An
Fonte: IOP PUBLISHING LTD; BRISTOL Publicador: IOP PUBLISHING LTD; BRISTOL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
67.789414%
The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10(17) eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e. g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest...

‣ The rapid atmospheric monitoring system of the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
67.78285%
The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10(17) eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e. g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest...

‣ An Android-Based Heart Monitoring System for the Elderly and for Patients with Heart Disease

Pierleoni, Paola; Pernini, Luca; Belli, Alberto; Palma, Lorenzo
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.615815%
The current trend in health monitoring systems is to move from the hospital to portable personal devices. This work shows how consumer devices like heart rate monitors can be used not only for applications in sports, but also for medical research and diagnostic purposes. The goal pursued by our group was to develop a simple, accurate, and inexpensive system that would use a few pieces of data acquired by the heart rate monitor and process them on a smartphone to (i) provide detailed test reports about the user's health state; (ii) store report records; (iii) generate emergency calls or SMSs; and (iv) connect to a remote telemedicine portal to relay the data to an online database. The system developed by our team uses sophisticated algorithms to detect stress states, detect and classify arrhythmia events, and calculate energy consumption. It is suitable for use by elderly subjects and by patients with heart disease (e.g., those recovering from myocardial infarction) or neurological conditions such as Parkinson's disease. Easy, immediate, and economical remote health control can therefore be achieved without the need for expensive hospital equipment, using only portable consumer devices.

‣ An MFC-Based Online Monitoring and Alert System for Activated Sludge Process

Xu, Gui-Hua; Wang, Yun-Kun; Sheng, Guo-Ping; Mu, Yang; Yu, Han-Qing
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 27/10/2014 Português
Relevância na Pesquisa
28.367017%
In this study, based on a simple, compact and submersible microbial fuel cell (MFC), a novel online monitoring and alert system with self-diagnosis function was established for the activated sludge (AS) process. Such a submersible MFC utilized organic substrates and oxygen in the AS reactor as the electron donor and acceptor respectively, and could provide an evaluation on the status of the AS reactor and thus give a reliable early warning of potential risks. In order to evaluate the reliability and sensitivity of this online monitoring and alert system, a series of tests were conducted to examine the response of this system to various shocks imposed on the AS reactor. The results indicate that this online monitoring and alert system was highly sensitive to the performance variations of the AS reactor. The stability, sensitivity and repeatability of this online system provide feasibility of being incorporated into current control systems of wastewater treatment plants to real-time monitor, diagnose, alert and control the AS process.

‣ Online Learning Algorithm for Time Series Forecasting Suitable for Low Cost Wireless Sensor Networks Nodes

Pardo, Juan; Zamora-Martinez, Francisco; Botella-Rocamora, Paloma
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/04/2015 Português
Relevância na Pesquisa
37.782852%
Time series forecasting is an important predictive methodology which can be applied to a wide range of problems. Particularly, forecasting the indoor temperature permits an improved utilization of the HVAC (Heating, Ventilating and Air Conditioning) systems in a home and thus a better energy efficiency. With such purpose the paper describes how to implement an Artificial Neural Network (ANN) algorithm in a low cost system-on-chip to develop an autonomous intelligent wireless sensor network. The present paper uses a Wireless Sensor Networks (WSN) to monitor and forecast the indoor temperature in a smart home, based on low resources and cost microcontroller technology as the 8051MCU. An on-line learning approach, based on Back-Propagation (BP) algorithm for ANNs, has been developed for real-time time series learning. It performs the model training with every new data that arrive to the system, without saving enormous quantities of data to create a historical database as usual, i.e., without previous knowledge. Consequently to validate the approach a simulation study through a Bayesian baseline model have been tested in order to compare with a database of a real application aiming to see the performance and accuracy. The core of the paper is a new algorithm...

‣ Cooperative Change Detection for Online Power Quality Monitoring

Li, Shang; Wang, Xiaodong
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/12/2014 Português
Relevância na Pesquisa
37.757065%
This paper considers the real-time power quality monitoring in power grid systems. The goal is to detect the occurrence of disturbances in the nominal sinusoidal voltage/current signal as quickly as possible such that protection measures can be taken in time. Based on an autoregressive (AR) model for the disturbance, we propose a generalized local likelihood ratio (GLLR) detector which processes meter readings sequentially and alarms as soon as the test statistic exceeds a prescribed threshold. The proposed detector not only reacts to a wide range of disturbances, but also achieves lower detection delay compared to the conventional block processing method. Then we further propose to deploy multiple meters to monitor the power signal cooperatively. The distributed meters communicate wirelessly to a central meter, where the data fusion and detection are performed. In light of the limited bandwidth of wireless channels, we develop a level-triggered sampling scheme, where each meter transmits only one-bit each time asynchronously. The proposed multi-meter scheme features substantially low communication overhead, while its performance is close to that of the ideal case where distributed meter readings are perfectly available at the central meter.

‣ Robust Online Monitoring of Signal Temporal Logic

Deshmukh, Jyotirmoy V.; Donzé, Alexandre; Ghosh, Shromona; Jin, Xiaoqing; Juniwal, Garvit; Seshia, Sanjit A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/06/2015 Português
Relevância na Pesquisa
38.453076%
Signal Temporal Logic (STL) is a formalism used to rigorously specify requirements of cyberphysical systems (CPS), i.e., systems mixing digital or discrete components in interaction with a continuous environment or analog com- ponents. STL is naturally equipped with a quantitative semantics which can be used for various purposes: from assessing the robustness of a specification to guiding searches over the input and parameter space with the goal of falsifying the given property over system behaviors. Algorithms have been proposed and implemented for offline computation of such quantitative semantics, but only few methods exist for an online setting, where one would want to monitor the satisfaction of a formula during simulation. In this paper, we formalize a semantics for robust online monitoring of partial traces, i.e., traces for which there might not be enough data to decide the Boolean satisfaction (and to compute its quantitative counterpart). We propose an efficient algorithm to compute it and demonstrate its usage on two large scale real-world case studies coming from the automotive domain and from CPS education in a Massively Open Online Course (MOOC) setting. We show that savings in computationally expensive simulations far outweigh any overheads incurred by an online approach.

‣ A Generic Multi-node State Monitoring Subsystem

Hamilton, James A.; Dubois-Felsmann, Gregory P.; Bartoldus, Rainer
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/05/2003 Português
Relevância na Pesquisa
28.082476%
The BaBar online data acquisition (DAQ) system includes approximately fifty Unix systems that collectively implement the level-three trigger. These systems all run the same code. Each of these systems has its own state, and this state is expected to change in response to changes in the overall DAQ system. A specialized subsystem has been developed to initiate processing on this collection of systems, and to monitor them both for error conditions and to ensure that they all follow the same state trajectory within a specifiable period of time. This subsystem receives start commands from the main DAQ run control system, and reports major coherent state changes, as well as error conditions, back to the run control system. This state monitoring subsystem has the novel feature that it does not know anything about the state machines that it is monitoring, and hence does not introduce any fundamentally new state machine into the overall system. This feature makes it trivially applicable to other multi-node subsystems. Indeed it has already found a second application beyond the level-three trigger, within the BaBar experiment.; Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003...

‣ A Data Capsule Framework For Web Services: Providing Flexible Data Access Control To Users

Kannan, Jayanthkumar; Maniatis, Petros; Chun, Byung-Gon
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/02/2010 Português
Relevância na Pesquisa
37.747034%
This paper introduces the notion of a secure data capsule, which refers to an encapsulation of sensitive user information (such as a credit card number) along with code that implements an interface suitable for the use of such information (such as charging for purchases) by a service (such as an online merchant). In our capsule framework, users provide their data in the form of such capsules to web services rather than raw data. Capsules can be deployed in a variety of ways, either on a trusted third party or the user's own computer or at the service itself, through the use of a variety of hardware or software modules, such as a virtual machine monitor or trusted platform module: the only requirement is that the deployment mechanism must ensure that the user's data is only accessed via the interface sanctioned by the user. The framework further allows an user to specify policies regarding which services or machines may host her capsule, what parties are allowed to access the interface, and with what parameters. The combination of interface restrictions and policy control lets us bound the impact of an attacker who compromises the service to gain access to the user's capsule or a malicious insider at the service itself.

‣ Recent Trends of Measurement and Development of Vibration Sensors

Chaurasiya, Himanshu
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/09/2012 Português
Relevância na Pesquisa
37.607676%
In recent trends, sensors are devices which monitor a parameter of a system, hopefully without disturbing that parameter. Vibration measurement has become an important method in mechanical structural products research, design, produce, apply and maintenance. Vibration sensor is more and more important as key devices. Nowadays, with the development of computer technology, electronic technology and manufacturing process, a variety of vibration sensors have come forth in succession.; Comment: 6 pages, 8 figures, International Journal of Computer Science Issues,Volume 9, Issue 4, No 1, July 2012; http://www.IJCSI.org, ISSN (Online): 1694-0814, July 2012

‣ Dependable Management of Untrusted Distributed Systems

Minsky, Naftaly
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/03/2014 Português
Relevância na Pesquisa
38.02292%
The conventional approach to the online management of distributed systems---represented by such standards as SNMP for network management, and WSDM for systems based on service oriented computing (SOC)---relies on the components of the managed system to cooperate in the management process, by providing the managers with the means to monitor their state and activities, and to control their behavior. Unfortunately, the trust thus placed in the cooperation of the managed components is unwarranted for many types of systems---such as systems based on SOA---making the conventional management of such systems unreliable and insecure. This paper introduces a radically new approach to the management of distributed systems, called governance-based management (GBM), which is based on a middleware that can govern the exchange of messages between system components. GBM has a substantial ability to manage distributed systems, in a reliable and secure manner, even without any trustworthy cooperation of the managed components. And it can fully incorporate the conventional management techniques wherever such cooperation can be trusted. GBM also supports a reflexive mode of management, which manages the management process itself, making it safer. However...

‣ Parallel low-overhead data collection framework for a resource centric performance analysis tool

Shrestha, Sunil
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.9367%
Gao, Guang R.; With the advent of multicore technology, computer systems have shifted to a new height of parallelism and computational power. Ramping up the frequency to in-crease performance on single processor has become a thing of the past. Nowadays, everyday computers are powered by multiple cores that share resources such as memory, network and I/O components. Moreover, they can run a larger gamut of applications at much higher speed. The increase in computational power is not re ected in the usability of such systems. The usage of these components and re-sources in an e ective manner puts an extremely high burden to the programmer and the system software, which increases the complexity in programming models and runtime systems. To alleviate this burden, there is a need for tools that can identify parallel sections in the code, identify bottlenecks and provides hint to the programmers to improve the performance of the overall computing system. More-over, the tool has to be able to pinpoint resource contentions so we know where uneven distributions of resources are. To address this issue, we introduced a tool called Memory Observant Data Analysis (MODA) [44]. MODA is a performance analysis tool that helps users analyze resource usage and alleviate resource con icts by pinpointing performance issues in an algorithmic as well as in an architectural level. The main challenge of any performance analysis tool is the tool performance itself. Performance analysis tool needs to be such that it introduces minimal to no pertur-bation of application behavior. This requires analysis tool to achieve information during runtime with a very minimal overhead. This is not easy to achieve because the tool has to not only monitor the behavior of an application but also record traces...