14708115
Distributed computing systems and checkpointing
This paper examines the performance of synchronous checkpointing in a distributed computing environment with and without load redistribution. Performance models are developed, and optimum checkpoint intervals are determined. The analysis extends earlier work by allowing for multiple nodes, state dependent checkpoint intervals, and a performance metric which is coupled with failure-free performance and the speedup functions associated with implementation of parallel algorithms. Expressions for the optimum checkpoint intervals for synchronous checkpointing with and without load redistribution are derived and the results are then used to determine when load redistribution is advantageous.<<ETX>>
16104056
Performance analysis and design of a logic simulation machine
The high costs associated with logic simulation of large VLSI circuits has led to the need for new computer architectures tailored to the simulation task. Such architectures have the potential for significant speed-ups over software-based logic simulators executing on standard sequential computers. This paper presents a model of one class of multiprocessor simulation architectures and compares the performance of some of these machines using data obtained from simulations of VLSI circuits. In addition, we discuss the implications of our results on machine design and examine the sensitivity of the model to variations in circuit characteristics.
11030217
The open network laboratory
The Open Network Laboratory (ONL) is a remotely accessible network testbed of high performance routers which has been designed with an eye towards ease of use for users from the naïve to the expert. The system is built around a set of high-performance routers that are extendible and easily configurable through the Remote Laboratory Interface (RLI), an intuitive graphical interface. The RLI also makes it easy to configure packet filters in the routers, assign flows or flow aggregates to separate queues with configurable QoS and attach hardware monitoring points to real-time charts. The RLI's real-time charts and user data facility make it easy to directly view the effects of traffic as it moves through a router, allowing the user to gain better insight into system behavior and create compelling demonstrations. Each port of the router is equipped with an embedded processor that supports software plugins which allow users to extend the system's functionality. This paper describes the ONL and how it can be used in networking education. Our web site onl.arl.wustl.edu includes a short video and a tutorial.
15226793
Code migration through transformations: an experience report
One approach to dealing with spiraling maintenance costs, manpower shortages and frequent breakdowns for legacy code is to "migrate" the code into a new platform and/or programming language. The objective of this paper is to explore the feasibility of semi-automating such a migration process in the presence of performance and other constraints for the migrant code. In particular, the paper reports on an experiment involving a medium-size software system written in PL/IX. Several modules of the system were migrated to C++, first by hand and then through a semiautomatic tool. After discovering that the migrant code was performing up to 50% slower than the original, a second migration effort was conducted which improved the performance of the migrant code substantially. The paper reports on the transformation techniques used by the transformation process and the effectiveness of the prototype tools that were developed. In addition, the paper presents preliminary results on the evaluation of the experiment.
690242
Improving Quality of Email Categorization with Tournament Methods
The tournament text classification methods are proposed in this article to perform the task of email categorization, in which the essence is to break down the multi-class categorization process into a set of binary classification tasks. We implement the methods of elimination and Round Robin tournament to classify emails within 15 folders. Substantial experiments are conducted to compare the effectiveness and robustness of the tournament methods against the n-way classification method and the voting method. The experimental results show that the tournament methods outperform the n-way method by 11.7% and the voting method by 4.1% regarding precision, and the Round Robin performs slightly better than the Elimination tournament on average.
35666520
Automatic Lyrics Alignment on Popular Music
8164588
Reconstruction and Motion Estimation from Apparent Contours under Circular Motion
In thispaperweaddresstheproblemof recoveringstructureandmotionfrom thecontoursof a smooth-curvedsurface.A novel andsimplertechniquefor computingthestructureof anobjectfrom its profilesis introduced.Experimentswith real datashow encouragingresults,which are comparableto thoseobtainedfrom muchmore sophisticatedtechniques.Furthermore,a new methodfor motion estimationfrom sequencesof profilesis proposed. Preliminaryresultsdemonstratethefeasibilityof thealgorithm.
50190
Application of aboutness to functional benchmarking in information retrieval
Experimental approaches are widely employed to benchmark the performance of an information retrieval (IR) system. Measurements in terms of recall and precision are computed as performance indicators. Although they are good at assessing the retrieval effectiveness of an IR system, they fail to explore deeper aspects such as its underlying functionality and explain why the system shows such performance. Recently, inductive (i.e., theoretical) evaluation of IR systems has been proposed to circumvent the controversies of the experimental methods. Several studies have adopted the inductive approach, but they mostly focus on theoretical modeling of IR properties by using some metalogic. In this article, we propose to use inductive evaluation for functional benchmarking of IR models as a complement of the traditional experiment-based performance benchmarking. We define a functional benchmark suite in two stages: the evaluation criteria based on the notion of "aboutness," and the formal evaluation methodology using the criteria. The proposed benchmark has been successfully applied to evaluate various well-known classical and logic-based IR models. The functional benchmarking results allow us to compare and analyze the functionality of the different IR models.