CORBA异步消息的研究与实现

异步机制是构造大规模分布式系统必不可少的机制之一.作为一种典型的分布应用支撑平台,CORBA没有很好的解决异步机制问题,这限制了CORBA在一些领域的应用.如何在CORBA中提供异步通信支持,为上层应用提供异步通信支持成为研究的热点.本文提出一种CORBA异步消息模型Star-Async,该模型通过ReplyHandler对象实现应答处理、通过异常封装对象实现异常处理,通过基于修改抽象语法树的机制实现异步代码生成.在自主研制的分布对象中间件平台StarBus中实现了本文提出的Star-Async异步模型,实现和初步应用表明本文提出的异步消息模型为在CORBA中实现异步机制提供了一种有效的参考.     

基于RS485接口的医院输液监控系统

介绍了一种用RS485构成的总线型的医院输液监控系统，包括上住机PC一台和下位机AT89C52单片机若干，下住机可以进行单独输液控制，也可以与上位机组成网络进行远程监控，整个系统使用灵活方便，具有很大的实用性。     

基于TMS320LF2407A的电机控制实验平台的设计

采用TI公司最新的面向电机控制的DSP芯片TMS320LF2407A，设计了一个通用的电机控制实验平台，用户可以在这个平台上进行异步电机、同步电机、直流电机等多种电机的各种控制策略的实验，使用非常方便灵活。     

分集接收混合遗传算法多用户检测器在异步CDMA移动通信中的应用研究

本文研究了将混合遗传法应用于码分多址扩频通信的多用户检测中，从而消除多址接入干扰的方法。本文先给出了在异步瑞利衰落信道下解调扩频信号的分集接收混合遗传算法多用户检测器的原理框图，然后分析了用混合遗传算法进行多用户检测的理论依据和实际性能。仿真结果表明无论是抗多址干扰还是抑制远近效应，分集接收混合遗传算法多用户检测器都明显优于传统接收机，其性能接近分集接收最佳多用户检测器。     

波峰焊机用三相异步感应式电泵的研究

开发出一种用三相异步感应泵波峰发生器的全自动单／双波峰焊机替代机械泵式波峰焊机，无任何转动部件，无磨损，免维护，提高了整机可行性。     

Influence of acoustic radiation on the sensors of a gyrostabilized platform

The paper analyzes the joint effect of acoustic radiation and angular motion of a launch vehicle on the gyroscopic sensors of a three-axis gyroplatform and the operation of the stabilizer under synchronous and asynchronous swinging.Translated from Prikladnaya Mekhanika, Vol. 40, No. 10, pp. 122–130, October 2004.     

Elastic basket switching

This paper proposes a new integrated switching system, ‘elastic basket switching’, for broadband and multimedia communications, including voice and high-speed data. In elastic basket switching (EBS), it is possible flexibly and efficiently to handle multimedia information by adaptively assigning communication resources according to communication requests and bandwidth of switched information. For continuous information, such as voice, EBS functions just as a circuit switching system, and for burst data it achieves high-efficiency bandwidth usage equivalent to a packet switching system by demand-assign type time-slot assignment. The detail of EBS and its application to a departmental system-orientated PBX are described. The traffic handling capability and details of the hardware structure are presented. The experimental system, including use of LSIs in the main parts of EBS is also described.     

Fairness in MIMD Congestion Control Algorithms

The Mulitplicative Increase Multiplicative Decrease (MIMD) congestion control algorithm in the form of Scalable TCP has been proposed for high speed networks. We study fairness among sessions sharing a common bottleneck link, where one or more sessions use the MIMD algorithm. Losses, or congestion signals, occur when the capacity is reached but could also be initiated before that. Both synchronous as well as asynchronous losses are considered. In the asynchronous case, only one session suffers a loss at a loss instant. Two models are then considered to determine which source looses a packet: a rate dependent model in which the packet loss probability of a session is proportional to its rate at the congestion instant, and the independent loss rate model. We first study how two MIMD sessions share the capacity in the presence of general combinations of synchronous and asynchronous losses. We show that, in the presence of rate dependent losses, the capacity is fairly shared whereas rate independent losses provide high unfairness. We then study inter protocol fairness: how the capacity is shared in the presence of synchronous losses among sessions some of which use Additive Increase Multiplicative Decrease (AIMD) protocols whereas the others use MIMD protocols.     

Stopping criteria, forward and backward errors for perturbed asynchronous linear fixed point methods in finite precision

^** Email: pierre.spiteri{at}enseeiht.fr This paper deals with perturbed linear fixed point methods inthe presence of round-off errors. Successive approximationsas well as the more general asynchronous iterations are treated.Forward and backward error estimates are presented, and theseare used to propose theoretical stopping criteria for thesemethods. In the case of asynchronous iterations, macro-iterationsare used as a tool in order to obtain estimates.     

Self-timed is self-checking

Self-checking circuits detect (at least some of) their own faults. We describe self-timed circuits, including combinational logic and sequential machines, which either halt or generate illegal output if they include any single stuck-at faults. The self-timed circuits employ dual rail data encoding to implement ternary logic of 0, 1, andundefined states; the fourth state is used to signal illegal output and is shown to result only from certain circuit faults. The self-timed circuits also employ four-phase signaling according to a well-defined protocol of communications between the circuit and its environment; failures due to certain faults prevent the circuit from communicating properly, thus causing the circuit to halt. We show that any single stuck-at fault falls in either the first or the second category, thus providing complete fault coverage through self checking. No hardware needs to be added to our circuits to achieve the complete self-checking property; further, the circuit is guaranteed to never generate a legal but erroneous output if it contains a fault. Minimal hardware is needed to detect that a circuit has either halted or has generated an illegal output.