UNIX进程间通信机制及应用的研究

ＵＮＩＸ操作系统是迄今为止使用得最广泛，最成功的一种分时，多用户，多任务操作系统，操作系统的所有工作都是通过一个个的进程为实现的。文章就ＵＮＩＸ进程的各种通信机制作了介绍，并介绍了利用这些机制模拟实用多用户条件下飞机订票系统的两种不同方案。     

天波超视距雷达工作频率点的自适应选择

该文提出了一种能够有效地提高高频段频谱资源利用率,自适应地为天波超视距雷达选择工作频率点的方法。该方法利用接收阵列的部分阵元做宽带接收,然后以一定的频率间隔用自适应波束形成的方法对干扰进行分析,并以子阵输出平均功率最小为准则选取最佳工作频率点。仿真结果表明,该方法能够有效地为天波超视距雷达提供最佳工作频率点。     

基于MODTRAN的红外系统作用距离变步长评估算法

在红外成像探测系统的作用距离评估中,要用到大气平均透过率参数,而它又是作用距离的函数,因而一般要用程序循环迭代的方法来计算作用距离。本文介绍了一种针对点目标探测的变步长作用距离评估方法,调用MODTRAN软件计算大气平均透过率和天空背景辐亮度,利用评估模型计算设定距离下的像元个数、信噪比和调制对比度,判断是否满足目标探测所需的最低性能指标,从而确定最大作用距离。在设定值与真实作用距离值相差较大时,采用较大的步长;在设定值与作用距离值相差较小时,采用较小的步长。相比固定步长法,可以在保持计算精度的同时,大大加快计算速度。     

High-power VLF transmitter facility utilizing a balloon lofted antenna

A 100-kW transportable very low-frequency (TVLF) transmitter facility has been used for magnetospheric wave-injection experiments from sites in Alaska, New Zealand, and Norway. A unique feature of the TVLF facility is the antenna which is a conducting cable lofted to an altitude of 1500 m by a 1000-m³helium balloon. The antenna is driven at its base as a monopole above a ground plane. The antenna cable also serves as the balloon tether. The lowest operating frequency in this configuration is 6.6 kHz, at which the radiated power is 100 W. At the highest operating frequency used in the experiments, 21 kHz, the radiated power is 10 kW. In Norway power lines were used as antennas. The minimum operating frequency was then 1 kHz and the radiated power is estimated to be about 0.5 W. The components and performance of the TVLF facility used with the balloon lofted antenna are described.     

A frameless stereotaxic operating microscope for neurosurgery

A new system, which we call the frameless stereotaxic operating microscope, is discussed. Its purpose is to display CT or other image data in the operating microscope in the correct scale, orientation, and position without the use of a stereotaxic frame. A nonimaging ultrasonic rangefinder allows the position of the operating microscope and the position of the patient to be determined. Discrete fiducial points on the patient's external anatomy are located in both image space and operating room space, linking the image data and the operating room. Physician-selected image information, e.g., tumor contours or guidance to predetermined targets, is projected through the optics of the operating microscope using a miniature cathode ray tube and a beam splitter. Projected images superpose the surgical field, reconstructed from image data to match the focal plane of the operating microscope. The algorithms on which the system is based are described, and the sources and effects of errors are discussed. The system's performance is simulated, providing an estimate of accuracy. Two phantoms are used to measure accuracy experimentally. Clinical results and observations are given.     

基于LPC2368的操作系统设计

在嵌入式系统开发的过程中,有时由于系统规模小、资源少而无需嵌入操作系统,这给习惯在操作系统下编程的开发人员带来很大的不便,针对这种情况该文在LPC2368上设计了一个轻型操作系统,实现了轮询式的任务调度,解决了无操作系统环境下编程的困扰。     

Optimizing Your Position on the Operating Curve: How Can a Fab Truly Maximize Its Performance?

An empirically grounded model of a fab operating curve that is sufficiently accurate to make capitalization decisions has identified preferred domains of fab performance. This finding contradicts extant theory, which argues that all operating points on the same operating curve should reflect the same level of performance. The model is used to simulate the performance of a stylized fab that operates under realistic conditions. Results of the simulation show that significant additional revenue and profit can be generated by extending the lean approach to managing the operating curve that is practiced in most fabs today to an approach that is both lean and value driven.      

Low-power method of adjustment of medium-wave directional antennas

A new simple method of measuring the operating impedances and adjusting medium-wave directive arrays is presented. The desired current ratios and phases in radiating towers are set up by using conventional pentode amplifiers and wide-range phase shifters. The operating input impedances can measured by means of an operating impedance bridge, or by a voltmeter method which is described in more detail. Once the operating impedances are known, the dummy loads can be used in final matching of the high-power phasor system.     

Relevance of receiver filter performance and operating range for CT2/CAI telepoint systems

A computer model is used to predict the effect of the interference between calls on the telepoint operating range. Results are given for the case of an interference rejection characteristic which just meets CAI requirements, and for an improved rejection characteristic. The improved characteristic was found to give a substantial increase in operating range.<>     

消息编程方法在电源嵌入式主机中的实现

通过介绍windows等操作系统和现在比较流行的嵌入式实时操作系统中消息的概念，并且将它推广应用到我们设计的分布式电源系统的嵌入式主机中。     

Analysis of a sectionalized tower as an element in a medium wavephased array using the method of moments

The use of method-of-moments techniques to obtain operating base parameters for a medium wave directional array is described. The array incorporates a 130' tall antenna element that is sectionalized 75' above the base. A matrix of impedance measurements is used to obtain input data for the MININEC analysis of the array. The MININEC output provides base operating parameters for the appropriate field values required to produce the desired pattern. When these values were used, the resulting measured antenna pattern was in close agreement with the original theoretical pattern which had been calculated using traditional assumptions     

Formal Representation of Meta-Operation of Chemical Plants

The synthesis of standard operating procedures (SOPs) of production and manufacturing plants is a complex process, which requires time and effort by process experts to ensure the completeness and accuracy of the target operating procedures. This research paper proposes a formal approach to structure and represent SOPs, which are used as a base to develop an automated operation management solution. Stimulated from the formal methods, and to overcome the complexity of plant operation, the concept of meta-operation is introduced as a set of generic operation libraries, which is used to simplify the definition of complex operation and to validate SOP. SOP formal language (SOPFL) is proposed to represent SOP as well as meta-operations in English-like formal statements, which includes vocabulary and rules. A SOPFL-based editor and parser are developed to automatically synthesize and validate the syntax and semantics of SOP for production plants. The proposed solution is used to synthesize SOPs and meta-operations of different case studies from batch and oil and gas plant processes.     

Ring voltage controlled oscillator for high-speed PLL systems

A circuit of a ring voltage controlled oscillator (VCO), which is to be used in high-speed phase-locked loop (PLL) systems integrated into programmable logic integrated circuits, is proposed. The maximum operating frequency of a VCO in 180 nm CMOS is shown by simulation to be able to reach 2 GHz in all operating conditions with the phase noise being ?99 dB/Hz and detuning frequency being 1 MHz.     

网格环境下 GridShell技术研究

为了方便传统的类UNIX系统用户使用网格，论文基于shell的基本思坦，提出了网洛环境下的一种命令行解释工具——GridShell，它支持类似于UNIX操作系统中的大部分命令行命令，并增加了Grid系统必需的一些命令，如greg负责网格用户与资源登记、gappRun负责应用程序在网格中的执行。在我们的实验网格Grid Wader上完成了Grid Shell的实现，并应用Grid Shell进行了网格资源共享和并行计算的试验。     

手术室局部洁净送风单元的研制

本文根据目前医院手术室建造中出现的问题,提出以使用手术室局部洁净送风单元做为缓解的办法。通过对送风单元的性能测试,指出:送风单元可以单独使用于对洁净度级别要求不高的手术室中,也可以在洁净度级别要求高的手术室中,配合使用送风单元进行局部强化送风。     

Assessment of the security of operating electric power systems using probability methods

A review is given of probability methods which have been proposed for the assessment of the security of operating electric power systems. The goal of all the methods presented is to provide the system operator with a consistent, on-line, indication of system security in the near-term future as a guide for operating decisions. Mathematical models used in the various methods are described and data requirements are discussed. Finally, areas of desirable future investigation are outlined.     

A semidigital dual delay-locked loop

This paper describes a dual delay-locked loop architecture which achieves low jitter, unlimited (modulo 2π) phase shift, and large operating range. The architecture employs a core loop to generate coarsely spaced clocks, which are then used by a peripheral loop to generate the main system clock through phase interpolation. The design of an experimental prototype in a 0.8-μm CMOS technology is described. The prototype achieves an operating range of 80 kHz-400 MHz. At 250 MHz, its peak-to-peak jitter with quiescent supply is 68 ps, and its jitter supply sensitivity is 0.4 ps/mV     

在迴旋管谐振迴路中利用缓变椭圆截面过渡段来抑制杂模的探讨

在迴旋管中圆截面谐振腔与圆环电子束相互作用是最合理的。但在这种腔中有与主模谐振频率极接近的杂模存在,本文探讨在相互作用区仍用圆截面谐振腔,而在互作用区外加进一段特殊设计的缓变椭圆过渡段用来抑制杂模的可能性。我们这样设计,其杂模场强能够延伸进过渡段而主模场强则不行;再在过渡段中加载,使其起到抑制杂模而保存主模(cTE0n和sTE1n)的作用。     

基于物联网和4G无线VPDN技术的实时视频监控系统的研究和应用

为实现国家电网南京分公司位于变电站内线路割接作业点的实时视频监控,中国电信股份有限公司南京分公司基于物联网技术,依托自身后端技术力量,利用4G无线百兆网络优势,通过创建4G VPDN（虚拟专用拨号网）智能管道（能够识别不同的业务类型进行控制和计费,并通过深度分组检测技术判断用户的类别,以提供不同水平的网络服务的信息传送网络）,实现了基于物联网和4G无线VPDN技术的实时视频监控系统方案,解决了变电站线路割接作业点由于位置经常变动,而无法使用有线方式实现实时视频监控的难题。     

共面波导(CPW)馈电单极子天线的设计与研究

给出一种工作于900MHz的共面波导(CPW)馈电单极子天线的设计。该单极子天线以共面波导的中心导带为辐射单极子，以中心导带两边的金属导体作反射板，结构简单紧凑。但是由于天线与共面波导之间缺少有效的隔离，造成天线性能受共面波导尺寸的影响较严重。本文通过模拟计算和实验测量详细分析了共面波导尺寸的变化对天线性能的影响，给出了结合共面波导尺寸设计的工作在900MHz的单极子天线结构数据。