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1.
Java provides portability and safety but falls short on efficiency. To resolve this problem, the authors developed Harissa, an execution environment that offers efficiency without sacrificing portability or dynamic class loading  相似文献   

2.
无线传感器网络TBCCA树形分簇算法   总被引:1,自引:0,他引:1  
针对当前无线传感器网络分簇和拓扑控制算法中存在的问题,例如能耗过大、负载不均、计算复杂性高和存在额外开销等,提出了一种新型的TBCCA(tree-based clustering construction algorithm)分簇算法.该算法基于正三角形簇树结构,并利用RSSI(received signal strength indicator)值控制簇半径,从而产生3类集合--Near集、Common集和Medium集,及其相应的选择策略.其后,根据树的度数和结构,设计了簇树的建立算法.性能分析和实验仿真表明,相对于现有的几种算法,例如TopDisc和DLMST等,TBCCA算法具有较低的计算复杂性;与Leach协议和HEED协议相比,该算法能在保证较高连通性与覆盖率的同时,有效节约能量,均衡负载,延长网络的生命周期.  相似文献   

3.
The FALCON development environment was designed around three basic data representations: scalars, vectors, and dense matrices. Utilizing the FALCON interactive restructuring system, the environment has been enhanced to allow the identification of structures within sparse matrices, such as diagonal matrices or symmetric matrices, and the use of this information for improving performance of the generated code. In addition, the environment supports the modification of the representation of the data. Such modifications have been shown to provide significant performance improvements.  相似文献   

4.
Although two-party password-authenticated key exchange (PAKE) protocols have been intensively studied in recent years, group PAKE protocols have received little attention. In this paper, we propose a tree-based group PAKE protocol——nnPAKE~+ protocol under the setting where each party shares an independent password with a trusted server. The nPAKE~+ protocol is a novel combination of the hierarchical key tree structure and the password-based Diffie-Hellman exchange, and hence it achieves substantial gain ...  相似文献   

5.
This paper describes an actor-based approach to real-time programming, which focuses on the separation of functional from timing behaviour. The approach favours modularity and time predictability. Clusters of actors, allocated on distinct processors, are orchestrated by a control machine which provides an event-driven and time-driven customisable scheduling framework. The approach can be hosted by Java, which fosters a clean and type-safe programming style. Temporal analysis can be formally assisted by Coloured Petri Nets.  相似文献   

6.
Verilog到Java翻译器VtoJ的设计与实现   总被引:1,自引:0,他引:1  
提出了一种将硬件描述语言Verilog转换到Java代码的设计方法,给出一组从Verilog到Java的转换规则。通过设计一个VtoJ翻译器完成自动转换功能,实现软硬件系统的协同仿真。  相似文献   

7.
《Advanced Robotics》2013,27(13-14):1603-1625
Dynamic manipulation of an active object is introduced as a general model of hopping and juggling tasks. In this setting, juggling and hopping are two extreme cases of this general model. Behavioral resemblance of these two tasks is afterwards extended to a detailed mathematical analogy between them. Then the analogy is exploited to develop a unified and abstract planning framework for juggling and hopping. To this end, dynamic manipulation of an active object is decomposed into three distinct phases and two transitions: Carry I, Free flight and Carry II phases. These phases are analogous to Lift off, Free flight and Touch down in hopping. In the next step, a mathematical model for each phase is developed. It is shown that dynamic grasp (in Carry phases of juggling) and foot stability (in Support phases of hopping) conditions share similar sets of dynamic equations. Accordingly, Lift off/Release and Touch down/Catch conditions in hopping/juggling are derived. It is shown that analogous strategies can be developed for Lift off and Release. The analogy is held for Touch down and Catch conditions as well. It is discussed that in the planning framework the initial and the goal configurations of the three phases are set in a model-based and forward manner. To do so, Touch down/Landing time, Free flight duration and robot/object maneuvers during Free flight are used as free parameters for planning in order to ensure foot stability in hopping and dynamic grasp in juggling along with other constraints.  相似文献   

8.
介绍了两种将Java应用于TMN的方法:一是将Java引入f参考点,以加强TMN工作站功能的性能;二是将Java引入移动代理,阐述了基于CORBA的移动代理如何增强TMN的管理功能。  相似文献   

9.
Java 3D实现VRML浏览器新途径   总被引:4,自引:1,他引:4  
Java是一种网络语言,Java 3D是Java语言在三维图形领域的扩充,它继承了Java许多优良的特性,Java3D能实现VRML绘制的所有三维图形,通过对Java 3D实现编译浏览VRML文件的分析,简要叙述了Java 3D的几何形体绘制、动画、交互技术,介绍了用Java语言编译VRML文件中遇到的一些技术问题。  相似文献   

10.
支持Multi-interface的Java程序MVC设计模式研究   总被引:2,自引:0,他引:2  
支持多类型用户界面的复杂应用程序架构设计一直是困扰企业的难题,文章引入源于Smalltalk的MVC架构设计思想,提出了具有经济性、可扩展性、安全性等支持多类型用户界面复杂应用程序的新型MVC设计模式,并分析了工作原理和性能特点。  相似文献   

11.
Today’s complex applications must face the distribution of data and code among different network nodes. Computation in distributed contexts is demanding increasingly powerful languages and execution environments, able to provide programmers with appropriate abstractions and tools. Java is a wide-spread language that allows developers to build complex software, even distributed, but it cannot handle the migration of computations (i.e. threads), due to intrinsic limitations of many traditional JVMs. After analyzing the approaches in the literature, this paper presents our thread migration framework (called Mobile JikesRVM), implemented on top of the IBM Jikes Research Virtual Machine (RVM): exploiting some of the innovative techniques in the JikesRVM, we implemented an extension of its scheduler that allows applications to easily capture the state of a running thread and makes it possible to restore it elsewhere (i.e. on a different hardware architecture or operating system), but still with a version of the framework installed). Our thread serialization mechanism provides support for both proactive and reactive migration, available also for multi-threaded Java applications, and tools to deal with the problems of resource relocation management. With respect to previous approaches, we implemented Mobile JikesRVM without recompiling its JVM (Java Virtual Machine) source code, but simply extending JikesRVM functionalities with a full Java package to be imported when thread migration is needed.  相似文献   

12.
文章从阐述接口定义语言(IDL)编译器在CORBA开发模型中的作用开始,提出了IDL编译器的开发模型,然后讨论了编译器的实现过程中的技术问题。  相似文献   

13.
Java存储模型是Java语言和Java虚拟机研究中的核心关键部分,目前Java语言规范中的存储模型不能保证Java技术所必需的语义特性,而且不利于Java虚拟机的性能优化.提出了一种新的Java存储模型,该模型取消了规范中Java存储模型中对存储密致性的要求,保证了Location一致性;同时根据Java语义的要求,对Java语言中不同类型的变量详细规定了多线程存储操作的行为规则.该模型不仅能保证Java程序的正确性,同时能有效提高Java程序的运行效率.最后通过仿真实验验证了该存储模型的关键特性.  相似文献   

14.
This paper presents a verifier for the memory-safe execution of extended Java bytecodes that support region-based memory management and explicit deallocation primitives. The verifier reads in region-annotated bytecodes that augment the standard Java bytecodes with instructions for creating and removing memory regions, allocating objects in regions, and passing regions as parameters. The verification ensures that each region is live when objects in the region are in use and that the program does not follow dangling references.The verifier requires region-safety certificates to be provided along with the bytecodes. The verification process consists of a load-time verification of method bodies, and a lazy linkage verification of method calls. Our region system supports both regions that are not lexically scoped and dangling pointers; the verifier proposed in this paper can successfully handle both of these features. Our experiments indicate that the sizes of certificates are acceptable in practice, and that region verification incurs little run-time overhead.  相似文献   

15.
利用Java实现基于Web的同步协同编辑器   总被引:1,自引:0,他引:1  
介绍了一种利用Java实现基于Web的同步协同编辑器的方法,该编辑器通过截获、分发和重构用户事件实现了群体感短、传输和现,并提供发言权控制、修改留痕等功能。  相似文献   

16.
介绍代理服务器的功能、工作原理,在Java语言开发环境下,实现代理服务器的基本功能。  相似文献   

17.
本文利用Java的字节码及其动态加载和执行的特性实现了数据库系统的存储过程。经过实验验证本文方法不仅仅可以在特定的数据库系统中加入存储过程,而且可以在大多数普通数据库系统中实现。  相似文献   

18.
Java程序混淆技术综述   总被引:2,自引:0,他引:2  
软件混淆技术已经广泛应用于抵制逆向工程和重组工程.文中从混淆技术的历史发展角度对现有的混淆技术理论、算法、攻击模式和评估进行了综述,将Java程序混淆算法分为类内混淆和类间混淆两个类别,并对其中的各类算法进行详尽的阐释.最后在现有工作的基础上,展望了软件混淆技术未来的发展与研究方向.  相似文献   

19.
The bytecode verification is a key point of the security chain of the Java Platform. This feature is optional in many embedded devices since the memory requirements of the verification process are too high. In this paper we propose a verification algorithm that remarkably reduces the use of the memory by performing the verification during multiple specialized passes. The algorithm reduces the type encoding space by operating on different abstractions of the domain of types. The results of the experiments show that this bytecode verification can be performed directly on small memory systems.  相似文献   

20.
Java语言多线程技术   总被引:3,自引:0,他引:3  
郭艳  刘福江 《现代计算机》2002,(2):20-22,41
本文从线程的概念及特点、多线程和多进程的区别以及死锁等基本原理出发,论述Java语言中的多线程机制-线程调度模式,同步互斥机制以及内置多线程功能,并对线程的状态,创建和控制方法以及避免死锁的方法作了深入的探讨。  相似文献   

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