10931722
STAS: A Scalability Testing and Analysis System
Scalability is a crucial factor in performance evaluation and analysis of parallel and distributed systems. Much effort has been devoted to scalability research and several metrics are proposed. However, the lacking of an effective scalability analysis toolkit is still a major barrier for researchers to measure and analyze scalabilities. Isospeed scalability is a known metric and has been extended for general computing systems recently. This paper proposes an effective scalability testing and analysis system, called STAS, and presents its implementation with isospeed-e scalability metric. STAS provides the facility to conduct automated isospeed-e scalability measure and analysis. It reduces the burden for users to evaluate the performance of algorithms and systems. Experiments have been conducted to verify the design and implementation
15987541
Quality-reliability chain modeling for system-reliability analysis of complex manufacturing processes
System reliability of a manufacturing process should address effects of both the manufacturing system (MS) component reliability, and the product quality. In a multi-station manufacturing process (MMP), the degradation of MS components at an upstream station can cause the deterioration of the downstream product quality. At the same time, the system component reliability can be affected by the deterioration of the incoming product quality of upstream stations. This kind of quality & reliability interaction characteristics can be observed in many manufacturing processes such as machining, assembly, and stamping. However, there is no available model to describe this complex relationship between product quality, and MS component reliability. This paper, considering the unique complex characteristics of MMP, proposes a new concept of quality & reliability chain (QR-Chain) effect to describe the complex propagation relationship of the interaction between MS component reliability, and product quality across all stations. Based on this, a general QR-chain model for MMP is proposed to integrate the product quality with the MS component reliability information for system reliability analysis. For evaluation of system reliability, both the exact analytic solution, and a simpler upper bound solution are provided. The upper bound is proved to be equal to the exact solution if the product quality does not have self-improvement, which is generally true in many MMP. Therefore, the developed QR-chain model, and its upper bound solution can be applied to many MMP.
417212
Taxonomy of Data Prefetching for Multicore Processors
Data prefetching is an effective data access latency hiding technique to mask the CPU stall caused by cache misses and to bridge the performance gap between processor and memory. With hardware and/or software support, data prefetching brings data closer to a processor before it is actually needed. Many prefetching techniques have been developed for single-core processors. Recent developments in processor technology have brought multicore processors into mainstream. While some of the single-core prefetching techniques are directly applicable to multicore processors, numerous novel strategies have been proposed in the past few years to take advantage of multiple cores. This paper aims to provide a comprehensive review of the state-of-the-art prefetching techniques, and proposes a taxonomy that classifies various design concerns in developing a prefetching strategy, especially for multicore processors. We compare various existing methods through analysis as well.
14925300
A Taxonomy of Data Prefetching Mechanisms
Data prefetching has been considered an effective way to mask data access latency caused by cache misses and to bridge the performance gap between processor and memory. With hardware and/or software support, data prefetching brings data closer to a processor before it is actually needed. Many prefetching techniques have been proposed in the last few years to reduce data access latency by taking advantage of multi-core architectures. In this paper, we propose a taxonomy that classifies various design concerns in developing a prefetching strategy. We discuss various prefetching strategies and issues that have to be considered in designing a prefetching strategy for multi-core processors.
61649411
Parallel I/O prefetching using MPI file caching and I/O signatures
Parallel I/O prefetching is considered to be effective in improving I/O performance. However, the effectiveness depends on determining patterns among future I/O accesses swiftly and fetching data in time, which is difficult to achieve in general. In this study, we propose an I/O signature-based prefetching strategy. The idea is to use a predetermined I/O signature of an application to guide prefetching. To put this idea to work, we first derived a classification of patterns and introduced a simple and effective signature notation to represent patterns. We then developed a toolkit to trace and generate I/O signatures automatically. Finally, we designed and implemented a thread-based client-side collective prefetching cache layer for MPI-IO library to support prefetching. A prefetching thread reads I/O signatures of an application and adjusts them by observing I/O accesses at runtime. Experimental results show that the proposed prefetching method improves I/O performance significantly for applications with complex patterns.
41542415
Reliability of two-stage weighted-k-out-of-n systems with components in common
This paper extends the existing one-stage weighted-k-out-of-n model to two-stage weighted-k-out-of-n models with components in common. Algorithms are developed to calculate the system reliability, and generate the minimal cuts & minimal paths of two-stage weighted-k-out-of-n systems. Reliability bounds for systems with s-dependent component failures are investigated based on the generated minimal cuts & minimal paths. Two types of two-stage weighted-k-out-of-n models, the SW-k-out-of-n model, and the PW-k-out-of-n model, can be applied to investigate reliability issues in network applications, such as the project management, and the shortest path problems. Examples are provided to demonstrate the developed models & algorithms.
16724396
Weighted Rough Graph and Its Application
Rough graph is the graph that can be used to research uncertainty problems, and it is a new research tool to analyze the rough characteristic of the system according to Tong He and Kaiquan Shi. This paper makes further research on rough graph, and gives the definitions of class connection of rough graph and some subgraphs of rough graph. Furthermore, this paper presents the definition of weighted rough graph by enduing the edges of rough graph with weight attribute, and gives the algorithm of exploring the class optimal tree in weighted rough graph, which generalizes the classical Kruskal algorithm of exploring the optimal tree. Finally, the application in relationship analysis shows the effectiveness of the algorithm
40119866
A fault tolerant topology control in wireless sensor networks
Summary form only given. Topology control of wireless sensor networks (WSNs) is a key design challenge in terms of extending the lifetime of the network. The paper presents a fault tolerant topology control by adding necessary redundant nodes to the network's simple communication backbone, which results a higher vertex connectivity degree. It provides not only fault tolerance for unreliable node failure, but also support for upper level protocols. The paper also identifies several factors and synchronization methods which may affect the redundant node selection. A simulation study shows the improvement of network lifetime with a desired vertex connectivity degree.
27063773
Aspect-Oriented Middleware-Based Real-Time and Embedded Systems Software Process
Middleware facilitates the development of real-time and embedded systems. However, middleware itself is becoming increasingly complex. Using the methodology of aspect-oriented software development to analyze and reconstruct the architecture of middleware can make the architecture more modularized and more customizable. In addition, since middleware plays a significant role in the realtime and embedded systems development, its characteristics must be considered in the entire real-time and embedded systems software process from requirements analyze phase to testing phase. This paper provides two contributions to the study of real-time and embedded systems development. First, presents the problems of current middleware architecture and analyzes functional requirements and non-functional requirements of aspect-oriented middleware. Second, proposes an aspect-oriented middleware based real-time and embedded systems software process. Both functional and non-functional characteristics of middleware are considered in all phases of the software process.
12162530
A new general algebraic method with symbolic computation to construct new doubly-periodic solutions of the (2 + 1)-dimensional dispersive long wave equation
For constructing more new exact doubly-periodic solutions in terms of rational form Jacobi elliptic function of nonlinear evolution equations, a new direct and unified algebraic method, named Jacobi elliptic function rational expansion method, is presented and implemented in a computer algebraic system. Compared with most of the existing Jacobi elliptic function expansion methods, the proposed method can be expected to obtain new and more general formal solutions. We choose a (2+1)-dimensional dispersive long wave equation to illustrate the method.
28565174
Trust Evolution Policies for Security in Collaborative Ad Hoc Applications
The vision of pervasive computing has introduced the notion of a vast, networked infrastructure of heterogeneous entities interact through collaborative applications, e.g., playing a multi-player online game on the way to work. This will require interactions between users who may be marginally known or completely unknown to each other, or in situations where complete information is unavailable. This introduces the problem of assigning access rights to such marginally known or unknown entities. Explicit trust management has emerged as a solution to the problem of dealing with partial information about other users and the context in which the interaction takes place. We have implemented an access control mechanism based on the human notion of trust, where recommendations or initial participation in low risk interactions will allow entities to slowly build trust in each other. As the trust between two entities grows, interactions that entail a higher degree of risk may be allowed to proceed. We have used this mechanism in a simple role-based access control mechanism that uses trust to assign roles to users in a distributed blackjack card game application. This application allows us to experiment with different policies for trust-based admission control and trust evolution. In this paper we present an evaluation of policies specifying trust dynamics, which shows that our prototype reacts appropriately to the behaviour of other users and that the system updates trust values and implements admission policies in a manner similar to what would be expected from human trust assessment. This indicates that trust evolution policies can replace explicit human intervention in application scenarios that are similar to the evaluated prototype.