We present the javaPorts system, an environment and a set of tools that allows non-expert users to easily develop parallel and distributed java applications targeting clusters of workstations. The javaPorts system can...
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We present the javaPorts system, an environment and a set of tools that allows non-expert users to easily develop parallel and distributed java applications targeting clusters of workstations. The javaPorts system can automatically generate java code templates for the tasks (software components) of an application, starting from a graph in which the user specifies how the tasks will be distributed to cluster nodes. Tasks have well defined port interfaces and may communicate by simply writing messages to their ports, without having to know the name and location of the destination task. This allows for task reusability while keeping the code for inter-task communication and coordination hidden. We demonstrate that coarse grain parallel programs developed using the javaPorts system achieve good performance, even when using a 10Mbs shared Ethernet network of workstations.
The labAlive toolbox allows the development of interactive, animated simulations and demonstrations of communication systems. Students can explore complex learning contents, and since the toolbox is implemented in Jav...
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The labAlive toolbox allows the development of interactive, animated simulations and demonstrations of communication systems. Students can explore complex learning contents, and since the toolbox is implemented in java, the training material can seamlessly be integrated into the World Wide Web. To make the development of customized wirings as easy as possible, a framework is provided for the simulation task, user interaction and display. An inheritance hierarchy with base classes implements these tasks, and a set of ready to use objects is provided, e.g. wires, standard systems like sine-wave generator and oscillographs. Developing a new wiring mainly consists of creating the required systems and wires, connecting up and defining the graphical layout. Special focus has been put on the extendability of the toolbox. New systems and also their graphical representation can easily be implemented.
java has potential as a programminglanguage for real-time systems. However although java has extensive documentation, there are no specifications about forecasting the task scheduling. In view of this, the Nilsons Re...
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java has potential as a programminglanguage for real-time systems. However although java has extensive documentation, there are no specifications about forecasting the task scheduling. In view of this, the Nilsons Real-Time java Specification which introduces a special pre-processor is introduced. As an implementation of this specification, the Portable Executive for Reliable Control (PERC) is given.
This paper gives an overview of the design of a mobile java object infrastructure. It describes why it is helpful to group objects for mobility and how, when clusters represent untrusted pieces of code (for example mo...
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This paper gives an overview of the design of a mobile java object infrastructure. It describes why it is helpful to group objects for mobility and how, when clusters represent untrusted pieces of code (for example mobile agents), they must be encapsulated both to control their access to other objects and to control access to them. The difficulties of managing large numbers of mobile objects in an open environment are discussed, together with a solution based on the management of large distributed name spaces. The mobile object system described has been implemented, and is currently being used to support development of mobile agent-based applications within another project. The paper also explains how the infrastracture described meets the requirements of mobile agents better than other approaches.
Interfacing java applications to a video-capture device poses a special challenge because there is currently no easy way to access the camera from java. The java virtual machine presents a barrier between applications...
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Interfacing java applications to a video-capture device poses a special challenge because there is currently no easy way to access the camera from java. The java virtual machine presents a barrier between applications and C/C++ application programming interfaces (API) used to access the video camera. To access these APIs from java, one must not only write JNI methods, but must also address image conversion problems, performance issues, and thread synchronization. The three approaches, no integration, loose integration, and full integration, to incorporate video or image capture into a java application and their abilities/complexity tradeoffs are discussed.
For an effective Internet-based distributed parallel computing platform, java-Internet Computing Environment (JICE) is designed and implemented with multithreading and remote method invocation mechanisms provided in J...
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For an effective Internet-based distributed parallel computing platform, java-Internet Computing Environment (JICE) is designed and implemented with multithreading and remote method invocation mechanisms provided in java. Specifically, JICE supports a shared memory system model for communication between any two nodes. Under the JICE, communication time is a major candidate of performance bottleneck. To reduce this communication overhead, a method of grouping is designed based on the optimal communication time. Communication performance given by grouping is evaluated through the analysis of execution time and verified via experiments. The results show that communication time can be reduced about 80% from executing some java benchmarks on JICE.
Events are used in distributed systems for monitoring purposes since internal states are often hidden from the observer. Composite events are recursively defined events upon conditions involving other events and occur...
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Events are used in distributed systems for monitoring purposes since internal states are often hidden from the observer. Composite events are recursively defined events upon conditions involving other events and occur whenever those conditions are satisfied. In systems where conditions on the occurrences of multiple events need to be monitored, composite events are extremely useful for clarifying the semantics of the conditions to be monitored and the correlation of simpler events. In this paper, we present a composite event package in java called JEM, which accepts and monitors the composite events specified in a java Event Specification language (JESL). JESL is developed based on a unified formalism presented in [14] for composite event and timing constraint specification. The system structure of JEM and its major components, i.e. Event Subscription Server;Composite Event Compiler and Monitor, are described in the paper. Some performance experiment results and the scalability issue of JEM are also discussed. The paper also demonstrates the practicality of JEM by explaining how a network event correlation application is built using JEM.
The World Wide Web has emerged as an effective mechanism for distributing educational material to students beyond the bounds of the classroom. The introduction of mobile code, such as java applets, combined with the p...
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The World Wide Web has emerged as an effective mechanism for distributing educational material to students beyond the bounds of the classroom. The introduction of mobile code, such as java applets, combined with the pervasiveness of the World Wide Web, present the potential to significantly enhance the development and distribution of educational software. This paper illustrates the design and implementation of a java applet for use in educational propulsion engineering curricula. The java Gas Turbine Simulator applet provides an interactive graphical environment which allows the rapid, efficient construction and analysis of arbitrary gas turbine systems. The simulation system couples a graphical user-interface and a transient, space-averaged, aero-thermodynamic gas turbine analysis method, both entirely coded in the javalanguage. The combined package provides analytical, graphical and data management tools which allow the student to construct and control dynamic gas turbine simulations by manipulating graphical objects on the computer display screen. The simulator, running as a java applet, can be easily accessed from the World Wide Web and run from a variety of heterogeneous computer platforms, including PCs, Macintosh, and UNIX machines, through the use of java-enabled Web browsers. (C) 1998 Elsevier Science Ltd. All rights reserved.
The rapid and widespread adoption of java has created a demand for reliable and reusable mathematical software components to support the growing number of computationally intensive applications now under development, ...
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The rapid and widespread adoption of java has created a demand for reliable and reusable mathematical software components to support the growing number of computationally intensive applications now under development, particularly in science and engineering. In this paper we address practical issues of the javalanguage and environment which have an effect on numerical library design and development. Benchmarks which illustrate the current levels of performance of key numerical kernels on a variety of java platforms me presented. Finally, a strategy for the development of a fundamental numerical toolkit for java is proposed and its current status is described, (C) 1998 John Wiley & Sons, Ltd.
java is a very promising language for use in the simulation of physical models due to its object-oriented nature, portability, robustness and support for multithreading. This paper presents JWarp, a java library for d...
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java is a very promising language for use in the simulation of physical models due to its object-oriented nature, portability, robustness and support for multithreading. This paper presents JWarp, a java library for discrete-event parallel simulations. It is based on an optimistic model for synchronization of the simulation entities: the Time Warp mechanism. We introduce the main features of the library and discuss some of the implementation details. (C) 1998 John Wiley & Sons, Ltd.
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