Martin Westhead

A benchmark suite for high performance Java

Increasing interest is being shown in the use of Java for large scale or Grande applications. This new use of Java places specific demands on the Java execution environments that could be tested and compared using a standard benchmark suite. We describe the design and implementation of such a suite, paying particular attention to Java-specific issues. Sample results are presented for a number of implementations of the Java Virtual Machine (JVM). Copyright

A methodology for benchmarking Java Grande applications

Increasing interest is being shown in the use of Java for large scale or Grande applications. This new use of Java places specific demands on the Java execution environments that could be tested and compared using a standard benchmark suite. EPCC has taken a leading role in the Java Grande Forum work to develop a framework and methodology for such a suite. Initial results presented here show interesting differences between JVMs, demonstrating the validity of the approach. Future work will concentrate on parallel benchmarks.

Automatic Characterisation of Musical Style

This paper describes a system for automatically characterising musical style using motifs. Motifs are patterns of rhythms or pitches common to more than one piece of music in a style. The Style Analysis with Motifs (SAM) system uses an original classification technique and is able to learn to distinguish between different styles with a success rate of over 95%. It is suggested that since motifs can be used to automatically discriminate between different styles effectively, they may be very important in the way humans achieve the task.

A multicenter validation of an active contour‐based left ventricular analysis technique

Quantitative analysis of functional cardiac magnetic resonance (MR) images has been limited by the lack of well‐validated, semiautomatic, methods for rapid analysis. We describe the evaluation of a DICOM‐compatible PC‐based parallel‐processing tool, for cardiac magnetic resonance analysis (CAMRA), which supports semiautomatic image mensuration using an active contour model‐based algorithm. The CAMRA software was used to analyze data from 12 patients in a multicenter acquisition and analysis trial to compare semiautomatic contour detection with manual planimetry of the left ventricular endocardium from short‐axis, breath‐held, cine gradient‐echo images. There was excellent agreement between the manual and semiautomatic measurements of global left ventricular function, with no significant (P = 0.32) difference in the determination of ejection fraction (−0.9 ± 3.1% [mean difference ± 1 standard deviation]). There was no significant interobserver difference in the semiautomatically measured ejection fraction. Additionally, a single observer completed the analysis on data from 30 patients and found no significant (P = 0.05) difference in the determination of ejection fraction (−1.3 ± 3.5% [mean difference ± 1 standard deviation]). The CAMRA software demonstrates the capability for the reproducible evaluation of global left ventricular function in cardiac patients, with adequate interobserver reproducibility for use in multicenter trials. J. Magn. Reson. Imaging 2000;12:232–239.

Verification of Embedded Systems Using Synchronous Observers

This paper is a study of observer-based proof techniques applied to the verification of a model of a real world embedded system, an aircraft landing gear. We present a formal description of these techniques (taken from [5]) and look at three ways of applying them, comparing verification of the composed system with two approaches to decompositional verification. The example illustrates that due to the tight interaction in a plant-controller setting there is often little to be gained by adopting a decompositional approach to verification. Nonetheless, two reasons are presented for separation between the controller and its environment at the modelling stage. Hence the result of the study is that in cases similar to this one, it is most expedient to prove system properties using the composed model derived from individual parts.

Describing data on the grid

The development of standards for describing format, structure and semantic content of data is essential for its automatic manipulation within a grid. We describe two related pieces of work that aim to address this need. BinX is a language with supporting tools and library for describing binary data, developed as part of the eDIKT project at the National eScience Centre. The data format description language (DFDL) is a global grid forum working group, which draws on the BinX work and aims to develop an extensible standard for describing these features of data formats.

Modeling hybrid systems as the limit of discrete computational processes

This paper outlines a new formalism for hybrid systems in which continuous dynamics are represented as the limit of a discrete computational process. Hybrid systems are systems which are composed of continuous and discrete components. Such systems often arise in robotics where operations in the continuous real world are controlled by a discrete software system. Most existing hybrid formalisms treat their continuous and discrete components as distinct types of process. This new approach brings the two together and provides a platform for the investigation of the transition between continuous change and discrete events.