Reflection amplification in thin layers of n-GaAs

Theoretical expressions are developed for the stability criterion and admittance of a thin coplanar GaAs reflection amplifier. The traveling-wave dispersion relation includes diffusion. The cathode boundary condition includes velocity modulation, injection, and distributed inhomogeneity effects. The admittance includes displacement currents running outside the semiconducting layer. The results show that the second to fifth harmonics may be more nearly unstable than the fundamental. Experiments on a coplanar epitaxial sample yield stable linear net gain at frequencies in the range 2 GHz-8 GHZ.     

Cost Optimization of Some Stochastic Maintenance Policies

This paper examines a preparedness policy of a stochastically failing system. It deals with two yet unsolved problems in the field of maintenance policies. Problem 1 analyzes a model that includes a discount factor. Problem 2 analyzes a model that includes maintenance costs that change over time. The models are solved by a conventional method and by dynamic programming.     

Comparison of two adaptive controllers

We are developing a simulation program to compare the performance of adaptive-control algorithms. Preliminary results indicate that a neutral control which includes caution, but not probing, is superior to the self-tuning regulator which includes neither.     

Measurement of ion density in a plasma torch using a plane probe

The plasma density of the flame of a plasma torch has been determined from the current to a plane probe using two theories. One includes only the ion flow motion; the other includes only the ion thermal motion. Comparison with spectroscopic results suggests that both motions should be included.     

ASP.NET之Web打印初探

Web打印是一种比较难以掌握但又应用很广并且非常实用的一种技术。现有的技术有自定义控件、使用IE直接打印等。而使用IE直接打印又可分为直接调用Window Print（ ）和使用WebBrowser控件等。着重讨论使用IE直接打印的方法。使用该方法有两个难点内容：一是如何控制只打印页面中需要的部分，忽略不需要打印的部分；二是如何设置打印预览、页面设置等功能。将进行初步的探讨。     

WCDMA网络优化方法和内容

在网络优化上,WCDMA系统同样要考虑2G系统中关注的覆盖、容量、质量等问题,但WCDMA系统面临的新挑战还包括软切换开销控制,主控区和隔离区的精确控制、系统干扰控制等新问题。网络优化方法主要包括现网调查、网络性能分析、指定优化方案及方案的实施和测试。优化内容包括覆盖优化、容量优化和无线资源管理优化。     

Implantable cardioverter defibrillators

The electrical design challenges for implantable defibrillators are discussed based on the following criteria: device evolution, system architecture, therapy delivery, mid heart activity sensing circuits. The discussion includes the incidence of sudden cardiac death and the clinical requirements of device hardware. System architecture includes the three dependent entities that define the system mid the functional components of the implanted device     

移动互联网的发展趋势及电信运营商的发展策略

认为电信运营商需重点发展三类平台和开展三大经营.三类平台包括：电子渠道、应用商店等渠道平台,通信、位置、支付、认证等重点能力型平台,音乐、智慧城市等重点业务平台;三大经营包括：流量经营、帐号经营、能力经营.以用户帐号为基础,构建了云端结合的用户共享基础设施平台.该平台包括用户识别、黏住及引导3个环节,可以实现用户资源盘活和价值提升.     

基于虚拟仪器的温度测量系统

基于虚拟仪器技术,利用热电偶设计了一套温度测量系统,包括硬件和软件设计,硬件包括对热电偶输出信号的放大和滤波,以及对冷端温度的补偿电路,冷端温度通过Pt100热电阻进行测量;软件采用Labview进行编写,界面简洁,可通过图形化的界面对温度进行实时监测。     

Routing framework for all-optical DWDM metro and long-haul transport networks with sparse wavelength conversion capabilities

In this paper, we propose a novel routing framework for all-optical dense wavelength-division-multiplexing transport networks with sparse wavelength conversion capabilities. The routing framework includes an integer linear programming formulation to handle the static lightpath establishment problem and a novel open shortest path first protocol extension that advertises the availability of wavelength usage and wavelength conversion resources. Our routing framework addresses the limitations of the extensions presented in the literature because it also includes: 1) an efficient flooding protocol that is suitable for the dynamic nature of these networks and 2) an efficient route and wavelength computation engine that minimizes connection costs without hindering the blocking probability.     

DUM14开关电源在集中监控系统的接入与测试

以DUM14开关电源为例，论述了其在武汉电信动力及环境集中监控系统(PSMS)中的接入方式和监控功能测试方法。接入方面包括协议、软件、端口等，监控功能测试包括模拟量、开关量、遥控量等。     

一种快速无线电监测接收机实现

研究了一种快速准确的信号识别系统,可应用于无线电监测。系统由模拟接收、数字接收和处理终端等部分构成,模拟接收部分和现有的无线电监视接收机具有相同的功能,数字接收包括适应不同带宽信号的多速率数据采集和数字下变频,数据实时地由 PCI 总线传输到处理终端,处理终端由微机和加裁的信号识别应用软件构成。试验证实了系统能正确完成数据采集、数据分析和快速准确识别信号等设计功能。系统还具有通用性的特点、功能可选择。     

Middleware 2004 Works in Progess

This issue includes the first two of six articles that will be presented asworks in progress at the conference, now in its fifth year.     

A one-chip scalable 8*8 ATM switch LSI employing shared bufferarchitecture

The authors present a one-chip scalable 8×8 shared buffer switch LSI which includes a 256-cell buffer. Speedup, flow control, and input slot rotation functions are provided in order to interconnect LSIs for scaling-up without degrading cell loss rates. Computer simulations show that these functions bring a satisfactory result and can make the cell loss- rate for a Clos three-stage network superior to that for the output buffer switch which includes the same amount of buffer space. A 0.8 μm BiCMOS process is employed for this LSI. The total number of transistors is one million. This LSI has already been fabricated     

Array and subarray pattern control features of subarraying feeds

The features of a space-feed lens subarraying system with amplitude control circuits at the feed array face are outlined in this analysis. Several concepts to aid in producing low sidelobe subarray patterns and subarray patterns with relatively wide band null troughs are introduced. The analysis is presented for the purpose of comparing alternative approaches and includes the diffraction effects of finite lens and array feed. It treats the idealization of the lens and array face as continuous apertures, neglects mutual coupling effects, and includes the assumption that the cylindrical lens back face is in the far field of the array feed.     

转换编码模拟实验平台

给出了转换编码模拟实验平台的简要构成，它包括视频编码、音频编码、复用／解复用、码流转换、分析、输出／播放及工具模块；着重剖析了作为搭建实验环境纽带的MPEG4IP软件包，包括MPEG-4视频、音频编码，码流复用、播放。实验表明，基于该平台可有效地进行转换编码研究。     

基于单片机的智能输液控制系统设计

围绕解决病人输液需要家属全程监护的问题,设计了基于单片机的智能输液控制系统.监护系统由主从站组成,其中从站由数据处理单片机和数据通信单片机组成,完成数据的采集、处理、控制等功能;主站由数据通信单片机摔制,主要完成通信功能.主从站之间采用无线模块PTR8000完成数据通信.     

Hyperspectral image data analysis

The fundamental basis for space-based remote sensing is that information is potentially available from the electromagnetic energy field arising from the Earth's surface and, in particular, from the spatial, spectral, and temporal variations in that field. Rather than focusing on the spatial variations, which imagery perhaps best conveys, why not move on to look at how the spectral variations might be used. The idea was to enlarge the size of a pixel until it includes an area that is characteristic from a spectral response standpoint for the surface cover to be discriminated. The article includes an example of an image space representation, using three bands to simulate a color IR photograph of an airborne hyperspectral data set over the Washington, DC, mall     

Development of a simulated data set for the SeaWiFS mission

A realistic simulated data set is essential for mission readiness preparations and can potentially assist in all phases of ground support for a future mission. Such a data set was created for the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), a global ocean color mission due for launch in 1997. This data set incorporates a representation of virtually every known aspect of the flight mission. Thus, it provides a high fidelity data set for testing most phases of the ground system, including data processing, data transfers, calibration and validation, quality control, and mission operations. The data set is constructed for a seven-day period, March 25-31, 1994. Specific features of the data set: it includes Global Area Coverage (GAC), recorded Local Area Coverage (LAC), and real-time High Resolution Picture Transmission (HRPT) data for the seven-day period; it includes a realistic orbit which is propagated using a Brouwer-Lyddane model with drag; the data correspond to a command schedule based on the orbit for this seven-day period; it includes total (at-satellite) radiances for ocean, land, clouds, and ice; it utilizes a high-resolution land/sea mask; it includes actual SeaWiFS spectral responses; it includes the actual sensor saturation responses; it is formatted according to current onboard data structures; and it includes corresponding telemetry (instrument and spacecraft) data. The methods are described and some examples of the output are given     

An analytical equation for the oscillation frequency of high-frequency ring oscillators

An analytical equation for the oscillation frequency of a ring oscillator is derived. The derivation is done using a novel method which does not need to find an expression for the delay of each stage. The resulting equation includes the effect of time-varying parasitics. It also includes the effect of the gate resistance, which has a large effect on the oscillation frequency at high frequencies. Measurement results of ring oscillators fabricated in a 0.18-/spl mu/m CMOS process show that the resulting equation has an average error of 8% over a large range of parameter variations.