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The Global ETD Search service is a free service for researchers
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Showing 1 to 10 of 10 (0.054 seconds)Spelling suggestions: "subject:"cynamic storage"" "subject:"clynamic storage""
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Data allocation design in computer networks.Lee, Heeseok. January 1991 (has links)
Well distributed data can dramatically improve the efficiency and effectiveness of the use of distributed database systems to satisfy geographically dispersed data processing demands. Among several issues related to distribution design in distributed databases, data allocation design is of major importance. Choices of a fragmentation strategy and location of database files are two critical decisions. Thus far, solutions of these design problems, although interdependent, have been attempted separately. Solving both design problems simultaneously in a real design setting is not a trivial task. By formulating typical data allocation design problems, we can analyze the solution space and analytical properties of optimal data allocation design. Based on this, we suggest that clustering data elements into uniform fragments and then allocating these fragments is equivalent to solving the data allocation design as a whole. Such analytical examination of the data allocation design problem has not been attempted by other researchers, but it is essential to provide the theoretical foundation for solving the fragmentation design and fragment allocation design problem. We then extended the research by studying the effect on design issues of such characteristics of distributed processing as database access patterns, network scope, and design objectives. We also propose a generic taxonomy of data allocation design models. We further advance data allocation design skills in the following two directions. The first of these involves developing a design method that guarantees the minimum number of fragments to be considered as units of allocation. This improves upon existing fragment allocation methodologies, which are based on the assumed units of allocation. The second direction involves enhancements in modeling and solution procedures that allow efficient fragment allocation design. Concentration is on information processing environments, which have received little attention in the research literature. We first studied databases connected on local area networks under weak locality of reference. The model proposed is validated by simulation study. We then explored the multiple design objective optimization phase, which involves searching for models where several design objectives are in conflict. We addressed three important design objectives including response time, operating cost and data availability. In conclusion, we submit that the methodology proposed is likely to provide a better understanding of data allocation design problems, the solutions for which are expected to continue providing key design tools as advancing data communication techniques evolve.
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Dynamic Storage Provisioning with SLO GuaranteesGaharwar, Prashant January 2010 (has links)
Static provisioning of storage resources may lead to over-provisioning of resources, which increases costs, or under-provisioning, which runs the risk of violating application-level QoS goals. Toward this end, virtualization technologies have made automated provisioning of storage resources easier allowing more effective management of the resources. In this work, we present an approach that suggests a series of dynamic provisioning decisions to meet the I/O demands of a time-varying workload while avoiding unnecessary costs and Service Level Objective (SLO) violations. We also do a case-study to analyze the practical feasibility of dynamic provisioning and the associated performance effects in a virtualized environment, which forms the basis of our approach. Our approach is able to suggest the optimal provisioning decisions, for a given workload, that minimize cost and meet the SLO. We evaluate the approach using workload data obtained from real systems to demonstrate its cost-effectiveness, sensitivity to various system parameters, and runtime feasibility for use in real systems.
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Dynamic Storage Provisioning with SLO GuaranteesGaharwar, Prashant January 2010 (has links)
Static provisioning of storage resources may lead to over-provisioning of resources, which increases costs, or under-provisioning, which runs the risk of violating application-level QoS goals. Toward this end, virtualization technologies have made automated provisioning of storage resources easier allowing more effective management of the resources. In this work, we present an approach that suggests a series of dynamic provisioning decisions to meet the I/O demands of a time-varying workload while avoiding unnecessary costs and Service Level Objective (SLO) violations. We also do a case-study to analyze the practical feasibility of dynamic provisioning and the associated performance effects in a virtualized environment, which forms the basis of our approach. Our approach is able to suggest the optimal provisioning decisions, for a given workload, that minimize cost and meet the SLO. We evaluate the approach using workload data obtained from real systems to demonstrate its cost-effectiveness, sensitivity to various system parameters, and runtime feasibility for use in real systems.
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A Lifetime-based Garbage Collector for LISP Systems on General-Purpose ComputersSobalvarro, Patrick 01 February 1988 (has links)
Garbage collector performance in LISP systems on custom hardware has been substantially improved by the adoption of lifetime-based garbage collection techniques. To date, however, successful lifetime-based garbage collectors have required special-purpose hardware, or at least privileged access to data structures maintained by the virtual memory system. I present here a lifetime-based garbage collector requiring no special-purpose hardware or virtual memory system support, and discuss its performance.
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Sensor de corrente transiente para detecção do SET com célula de memória dinâmicaSimionovski, Alexandre January 2012 (has links)
Esta dissertação trata do projeto e avaliação de um novo circuito sensor de corrente com célula de memória dinâmica para a detecção de correntes transientes em circuitos integrados CMOS, provocadas pela incidência de partículas ionizantes. As propostas previamente existentes na literatura são avaliadas e suas deficiências são apontadas. É apresentada a topologia e o modo de funcionamento do novo circuito, juntamente com o detalhamento do projeto das versões destinadas à monitoração dos transistores PMOS e NMOS. É apresentado o layout do circuito final em tecnologia 130 nm, destinado à prototipação pelo programa MOSIS, contendo os sensores, os transistores-alvo, os estágios de saída e os circuitos de proteção contra os efeitos da eletricidade estática necessários. Os resultados obtidos através de simulação mostram que o novo circuito proporciona uma redução na área de silício necessária para a implementação, bem como um menor consumo de corrente quiescente em relação às propostas anteriores. / This dissertation deals with the design and evaluation of a new current sensor circuit with dynamic memory cell intended to detect transient currents caused by incidence of ionizing particles in CMOS integrated circuits. Circuits previously proposed are analyzed and their drawbacks are pointed out. The new circuit topology and working principle is presented, along with the detailed design of the versions intended to monitoring PMOS and NMOS transistors. The final circuit is laid out in a 130 nm technology, intended to be prototyped through the MOSIS program. The complete design contains the sensor circuits, target transistors, output stages and electrostatic discharge protection circuitry. Results obtained by post layout simulation shown that the new circuit provides a reduction on silicon area and a smaller quiescent current consumption compared to previous circuits.
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Sensor de corrente transiente para detecção do SET com célula de memória dinâmicaSimionovski, Alexandre January 2012 (has links)
Esta dissertação trata do projeto e avaliação de um novo circuito sensor de corrente com célula de memória dinâmica para a detecção de correntes transientes em circuitos integrados CMOS, provocadas pela incidência de partículas ionizantes. As propostas previamente existentes na literatura são avaliadas e suas deficiências são apontadas. É apresentada a topologia e o modo de funcionamento do novo circuito, juntamente com o detalhamento do projeto das versões destinadas à monitoração dos transistores PMOS e NMOS. É apresentado o layout do circuito final em tecnologia 130 nm, destinado à prototipação pelo programa MOSIS, contendo os sensores, os transistores-alvo, os estágios de saída e os circuitos de proteção contra os efeitos da eletricidade estática necessários. Os resultados obtidos através de simulação mostram que o novo circuito proporciona uma redução na área de silício necessária para a implementação, bem como um menor consumo de corrente quiescente em relação às propostas anteriores. / This dissertation deals with the design and evaluation of a new current sensor circuit with dynamic memory cell intended to detect transient currents caused by incidence of ionizing particles in CMOS integrated circuits. Circuits previously proposed are analyzed and their drawbacks are pointed out. The new circuit topology and working principle is presented, along with the detailed design of the versions intended to monitoring PMOS and NMOS transistors. The final circuit is laid out in a 130 nm technology, intended to be prototyped through the MOSIS program. The complete design contains the sensor circuits, target transistors, output stages and electrostatic discharge protection circuitry. Results obtained by post layout simulation shown that the new circuit provides a reduction on silicon area and a smaller quiescent current consumption compared to previous circuits.
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Sensor de corrente transiente para detecção do SET com célula de memória dinâmicaSimionovski, Alexandre January 2012 (has links)
Esta dissertação trata do projeto e avaliação de um novo circuito sensor de corrente com célula de memória dinâmica para a detecção de correntes transientes em circuitos integrados CMOS, provocadas pela incidência de partículas ionizantes. As propostas previamente existentes na literatura são avaliadas e suas deficiências são apontadas. É apresentada a topologia e o modo de funcionamento do novo circuito, juntamente com o detalhamento do projeto das versões destinadas à monitoração dos transistores PMOS e NMOS. É apresentado o layout do circuito final em tecnologia 130 nm, destinado à prototipação pelo programa MOSIS, contendo os sensores, os transistores-alvo, os estágios de saída e os circuitos de proteção contra os efeitos da eletricidade estática necessários. Os resultados obtidos através de simulação mostram que o novo circuito proporciona uma redução na área de silício necessária para a implementação, bem como um menor consumo de corrente quiescente em relação às propostas anteriores. / This dissertation deals with the design and evaluation of a new current sensor circuit with dynamic memory cell intended to detect transient currents caused by incidence of ionizing particles in CMOS integrated circuits. Circuits previously proposed are analyzed and their drawbacks are pointed out. The new circuit topology and working principle is presented, along with the detailed design of the versions intended to monitoring PMOS and NMOS transistors. The final circuit is laid out in a 130 nm technology, intended to be prototyped through the MOSIS program. The complete design contains the sensor circuits, target transistors, output stages and electrostatic discharge protection circuitry. Results obtained by post layout simulation shown that the new circuit provides a reduction on silicon area and a smaller quiescent current consumption compared to previous circuits.
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How Often do Experts Make Mistakes?Palix, Nicolas, Lawall, Julia L., Thomas, Gaël, Muller, Gilles January 2010 (has links)
Large open-source software projects involve developers with a wide variety of backgrounds and expertise. Such software projects furthermore include many internal APIs that developers must understand and use properly. According to the intended purpose of these APIs, they are more or less frequently used, and used by developers with more or less expertise. In this paper, we study the impact of usage patterns and developer expertise on the rate of defects occurring in the use of internal APIs. For this preliminary study, we focus on memory management APIs in the Linux kernel, as the use of these has been shown to be highly error prone in previous work. We study defect rates and developer expertise, to consider e.g., whether widely used APIs are more defect prone because they are used by less experienced developers, or whether defects in widely used APIs are more likely to be fixed.
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Malleability, obliviousness and aspects for broadcast service attachmentHarrison, William January 2010 (has links)
An important characteristic of Service-Oriented Architectures is that clients do not depend on the service implementation's internal assignment of methods to objects. It is perhaps the most important technical characteristic that differentiates them from more common object-oriented solutions. This characteristic makes clients and services malleable, allowing them to be rearranged at run-time as circumstances change. That improvement in malleability is impaired by requiring clients to direct service requests to particular services. Ideally, the clients are totally oblivious to the service structure, as they are to aspect structure in aspect-oriented software. Removing knowledge of a method implementation's location, whether in object or service, requires re-defining the boundary line between programming language and middleware, making clearer specification of dependence on protocols, and bringing the transaction-like concept of failure scopes into language semantics as well. This paper explores consequences and advantages of a transition from object-request brokering to service-request brokering, including the potential to improve our ability to write more parallel software.
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AspectKE*: Security aspects with program analysis for distributed systemsFan, Yang, Masuhara, Hidehiko, Aotani, Tomoyuki, Nielson, Flemming, Nielson, Hanne Riis January 2010 (has links)
Enforcing security policies to distributed systems is difficult, in particular, when a system contains untrusted components. We designed AspectKE*, a distributed AOP language based on a tuple space, to tackle this issue. In AspectKE*, aspects can enforce access control policies that depend on future behavior of running processes. One of the key language features is the predicates and functions that extract results of static program analysis, which are useful for defining security aspects that have to know about future behavior of a program. AspectKE* also provides a novel variable binding mechanism for pointcuts, so that pointcuts can uniformly specify join points based on both static and dynamic information about the program. Our implementation strategy performs fundamental static analysis at load-time, so as to retain runtime overheads minimal. We implemented a compiler for AspectKE*, and demonstrate usefulness of AspectKE* through a security aspect for a distributed chat system.
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