Sung Hoon Ko

MPIJAVA: An Object-Oriented JAVA Interface to MPI

A basic prerequisite for parallel programming is a good communication API. The recent interest in using Java for scientific and engineering application has led to several international efforts to produce a message passing interface to support parallel computation. In this paper we describe and then discuss the syntax, functionality and performance of one such interface, mpiJava, an object-oriented Java interface to MPI. We first discuss the design of the mpiJava API and the issues associated with its development. We then more on to briefly outline the steps necessary to ‘port’ mpiJava onto a range of operating systems, including Windows NT, Linux and Solaris. In the second part of the paper we present and then discuss some performance measurements made of communications bandwidth and latency to compare mpiJava on these systems. Finally, we summarise our experiences and then briefly mention work that we plan to undertake.

Object serialization for marshalling data in a Java interface to MPI

Several Java bindings to Message Passing Interface (MPI) software have been developed recently. Message bu ers have usually been restricted to arrays with elements of primitive type. We discuss adoption of the Java object serialization model for marshalling general communication data in MPI-like APIs. This approach is compared with a Java transcription of the standard MPI derived datatype mechanism. We describe an implementation of the mpiJava interface to MPI that incorporates automatic object serialization. Benchmark results con rm that current JDK implementations of serialization are not fast enough for high performance messaging applications. Means of solving this problem are discussed, and benchmarks for greatly improved schemes are presented.

Grid services for earthquake science

We describe an information system architecture for the ACES (Asia–Pacific Cooperation for Earthquake Simulation) community. It addresses several key features of the field—simulations at multiple scales that need to be coupled together; real‐time and archival observational data, which needs to be analyzed for patterns and linked to the simulations; a variety of important algorithms including partial differential equation solvers, particle dynamics, signal processing and data analysis; a natural three‐dimensional space (plus time) setting for both visualization and observations; the linkage of field to real‐time events both as an aid to crisis management and to scientific discovery. We also address the need to support education and research for a field whose computational sophistication is rapidly increasing and spans a broad range. The information system assumes that all significant data is defined by an XML layer which could be virtual, but whose existence ensures that all data is object‐based and can be accessed and searched in this form. The various capabilities needed by ACES are defined as grid services, which are conformant with emerging standards and implemented with different levels of fidelity and performance appropriate to the application. Grid Services can be composed in a hierarchical fashion to address complex problems. The real‐time needs of the field are addressed by high‐performance implementation of data transfer and simulation services. Further, the environment is linked to real‐time collaboration to support interactions between scientists in geographically distant locations. Copyright

Cost model and adaptive scheme for publish/subscribe systems on mobile grid environments

Publish/subscribe model is appropriate in many push based data dissemination applications. This paper presents cost model for publish/subscribe systems, analyze its performance, and compare to other interaction-based models such as the client-server model and the polling model. Based on the cost analysis, we have proposed an adaptive model which can dynamically select an appropriate model for each client independently.

Publish/Subscribe systems on node and link error prone mobile environments

Publish/subscribe model is appropriate in many push based data dissemination applications such as data dissemination services, information sharing, service discovery, etc. Recently, theses types systems are rapidly adopted in mobile and ubiquitous environment. However, mobile and ubiquitous environments are error prone due to wireless link disconnection, power exhaustion on mobile devices, etc. We analyze performance and effectiveness of publish/subscribe systems on the failure of client and server nodes and disconnection of communication links, which is common in mobile environments. We also perform experiments on our test bed to verify correctness and usefulness of our analysis.