For processing of incomplete data values in large-scale, incomplete databases, a hybrid, knowledge-based model is constructed to perform decision-aiding. The most important part of this model is a decision-making netw...
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For processing of incomplete data values in large-scale, incomplete databases, a hybrid, knowledge-based model is constructed to perform decision-aiding. The most important part of this model is a decision-making network. Parallel computation of the network is key to achieving good performance of the entire system. In this paper, a multithreaded solution is introduced for exploring parallelism in the computation of the decision-making network, and the data flow graph is presented. The proposed method is implemented with java threads. This solution can be used for parallelizing the computation of decision-making networks of varying sizes.
java-Web Computing paradigm changed Internet into computing environment. For java-Web Computing and many java applications, a new java processor, called simultaneous multithreaded (SMT) javaChip, is proposed to enhanc...
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java-Web Computing paradigm changed Internet into computing environment. For java-Web Computing and many java applications, a new java processor, called simultaneous multithreaded (SMT) javaChip, is proposed to enhance the performance of previous java processor by hardware support of java multithreading. SMT javaChip is a modified architecture with the enhanced mechanism of stack cache, instruction cache, functional units, and etc. It executes dual independent threads simultaneously and enhances instruction level parallelism. The performance of SMT javaChip is evaluated through the simulation using javaSim, a java processor simulator. This research is focused to enhance the performance of java processor by considering the characteristics of javalanguage and computation environment. Performance results show that SMT javaChip can provide the execution speedup of between 1.28 and 2.00 compared with the single threaded java processors.
Threads and concurrency constructs in java introduce non-determinism to a program's execution, which makes it hard to understand and analyze the execution behavior. Non-determinism in execution behavior also makes...
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Threads and concurrency constructs in java introduce non-determinism to a program's execution, which makes it hard to understand and analyze the execution behavior. Non-determinism in execution behavior also makes it impossible to use execution replay for debugging, performance monitoring, or visualization. This paper discusses a record/ replay tool for java, DejaVu, that provides deterministic replay of a program's execution. In particular, this paper describes the idea of the logical thread schedule, which makes DejaVu efficient and independent of the underlying thread scheduler. The paper also discusses how to handle the various java synchronization operations for record and replay. DejaVu has been implemented by modifying the Sun Microsystems' java Virtual Machine.
We defined a new concept of microscope system for telepathology, named World Wide Microscope (WWM), and implemented its prototype. WWM is constructed by the following three units;(1) microscope unit, (2) control unit,...
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This paper gives a mathematical specification the java Virtual Machine (JVM) bytecode verifier. The specification is an axiomatic description of the verifier that makes precise subtle aspects of the JVM semantics and ...
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This paper gives a mathematical specification the java Virtual Machine (JVM) bytecode verifier. The specification is an axiomatic description of the verifier that makes precise subtle aspects of the JVM semantics and the verifier. We focus on the use of data flow analysis to verify type-correctness and the use of typing contexts to insure global type consistency in the context of a lazy strategy for class loading. The specification types interfaces with sufficient accuracy to eliminate run-time type checks. Our approach is to specify a generic dataflow architecture and formalize the JVM verifier as an instance of this architecture. The emphasis in this paper is on readability of the specification and mathematical clarity. The specification given is consistent with the descriptions in the Lindholm's and Yellin's The javaTM Virtual Machine Specification. It less committed to implementation choices regarding when classes are loaded than Sun's version 1.1 implementation.
This paper describes an implementation of java [1] on the Inferno operating system. There are applications for which object oriented designs are the appropriate solution. java is an object oriented programming languag...
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As multimedia capable computers become cheaper and more pervasive in the consumer and corporate markets, and as the availability of digital information increases, the need for low-cost, cross-platform multimedia appli...
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language-supported synchronization is a source of serious performance problems in many java programs. Even single-threaded applications may spend up to half their time performing useless synchronization due to the thr...
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language-supported synchronization is a source of serious performance problems in many java programs. Even single-threaded applications may spend up to half their time performing useless synchronization due to the thread-safe nature of the java libraries. We solve this performance problem with a new algorithm that allows lock and unlock operations to be performed with only a few machine instructions in the most common cases. Our locks only require a partial word per object, and were implemented without increasing object size. We present measurements from our implementation in the JDK 1.1.2 for AIX, demonstrating speedups of up to a factor of 5 in micro-benchmarks and up to a factor of 1.7 in real programs.
The aim of the Do! project is to ease the standard task of programming distributed applications using java. This paper gives an overview of the parallel and distributed frameworks and describes the mechanisms develope...
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ISBN:
(纸本)3540649522
The aim of the Do! project is to ease the standard task of programming distributed applications using java. This paper gives an overview of the parallel and distributed frameworks and describes the mechanisms developed to distribute programs with Do!.
Full precision in garbage collection implies retaining only those heap allocated objects that will actually be used in the future. Since full precision is not computable in general, garbage collectors use safe (i.e., ...
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Full precision in garbage collection implies retaining only those heap allocated objects that will actually be used in the future. Since full precision is not computable in general, garbage collectors use safe (i.e., conservative) approximations such as reachability from a set of root references. Ambiguous roots collectors (commonly called `conservative') can be overly conservative because they overestimate the root set, and thereby retain unexpectedly large amounts of garbage. We consider two more precise collection schemes for java virtual machines (JVMs). One uses a type analysis to obtain a type-precise root set (only those variables that contain references);the other adds a live variable analysis to reduce the root set to only the live reference variables. Even with the java programming language's strong typing, it turns out that the JVM specification has a feature that makes type-precise root sets difficult to compute. We explain the problem and ways in which it can be solved. Our experimental results include measurements of the costs of the type and liveness analyses at load time, of the incremental benefits at run time of the liveness analysis over the type analysis alone, and of various map sizes and counts. We find that the liveness analysis often produces little or no improvement in heap size, sometimes modest improvements, and occasionally the improvement is dramatic. While further study is in order, we conclude that the main benefit of the liveness analysis is preventing bad surprises.
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