发达国家的几种卫星应用考虑

介绍了加拿大、美国、德国、法国不同的卫星应用考虑。加拿大拟用2颗卫星在2007年前后获得近乎全球高精度的地球高低数据,美国着重于开发全球性的侦察和作战用的卫星群,德国和法国则试图用一发数收小卫星来解决SAR/MTI。     

Reliability and availability analysis of systems operating in multiple environments

This paper presents two newly developed stochastic models which can represent engineering systems operating in different types of environments. Laplace transforms of the state probabilities, system reliability and availability equations are developed. In addition, steady-state availability and mean-time-to-failure expressions are developed and their plots are shown.     

Hazard Modification Techniques for Repair and Multiple Operating Conditions

Two modeling techniques for simulating availability are developed. A technique is developed for introducing multiple operating conditions into simulation models. Another technique is developed for incorporating an operating-time adjustment for repair in availability simulations. A general operating-time adjustment-technique is developed and then two special cases of this technique are discussed. The two modeling techniques developed in this paper allow the availability engineer to obtain more detail in availability studies. These techniques were used in the Farm Machinery Availability Cost Simulation Model.     

Quantitative design and evaluation of enhancement/thresholding edge detectors

Quantitative design and performance evaluation techniques are developed for the enhancement/thresholding class of image edge detectors. The design techniques are based on statistical detection theory and deterministic pattern-recognition classification procedures. The performance evaluation methods developed include: a)deterministic measurement of the edge gradient amplitude; b)comparison of the probabilities of correct and false edge detection; and c) figure of merit computation. The design techniques developed are used to optimally design a variety of small and large mask edge detectors. Theoretical and experimental comparisons of edge detectors are presented.     

A methodology for fast scheduling of partitioned systolic algorithms

Various methods for mapping signal processing algorithms into systolic arrays have been developed in the past few years. In this paper, efficient scheduling techniques are developed for the partitioning problem, i.e. problems with size that do not match the array size. In particular, scheduling for the Locally Parallel-Globally Sequential (LPGS) technique and the Locally Sequential-Globally Parallel (LSGP) technique are developed. The scheduling procedure developed exploits the fact that after LPGS and LSGP partitioning, the locality constraints are less stringent allowing for more flexibility in the choice of algorithms and inter-processor communication. A flexible scheduling order is developed that is useful in evaluating the trade-off between execution time and size of storage buffers. The benefits of the scheduling techniques are illustrated with the help of matrix multiplication and least squares examples. This work was supported in part by the UCSD/NSF Integrated Circuits And Systems Research Center and by the ARMY Research Office under Grant No. DAAL-03-90-G-0095.     

薄膜晶体管矩阵液晶显示器的无缺陷技术

分析了薄膜晶体管矩阵液晶显示器的缺陷分类,成因,研制了ＴＦＴ－ＬＣＤ短,断路缺陷检测和全板显示检测的测试析,系统介绍了各种缺陷的激光补技术和ＴＦＴ－ＬＣＤ屏的冗余技术,作者在美期间开发出了利用减法激光修补仪进行加法修补的独特工艺。     

考虑多次散射的复杂目标一体化电磁散射计算

在复杂目标电磁散射计算中,表面散射、棱边散射以及凹形结构的多次散射是最为重要的几种散射贡献。研 究了包含表面散射、棱边散射和凹形结构多次散射的复杂目标一体化电磁散射计算方法,开发了基于UG 建模软件的 一体化电磁散射计算软件,其中表面散射计算采用了图形电磁计算方法,棱边散射算法采用ILDC,并使用UG/Open 实现了复杂目标棱边自动识别,对于包含多次散射的腔体等凹形结构,开发了基于NURBS 曲面的射线追踪方法和SBR 算法,实现了腔体结构多次散射计算。所有算法都统一在UG 建模软件中开发,实现了从目标几何建模到散射计算的 一体化,简化了模型前处理过程。算例表明,所开发的一体化散射计算软件计算精度高,通用性强,具有很好的工程 应用价值。     

Integrated Front-End Radar Receivers at Ka-Band

This paper describes the Integrated Finline Front-end Radar Receivers at Ka-Band. The Front-receivers developed for Radar applications include combining of finline components on a single MIC substrate with various planar transmission lines. The integrated systems so developed have better noise figure and control over phase and gain imbalances as compared to discrete component systems. Two types of Integrated Front-ends Radar receivers are described here. The developed systems are highly compact and reliable.     

Reliability evaluation of human operators under stress

This paper presents five newly developed models to predict reliability of human operators performing time continous tasks under stress. Laplace transforms of state probability equations and operator reliability are developed. Mean time to human error (MTTHE) expressions are obtained. In addition specific plots are shown for selective models.     

Efficient and accurate modeling of planar anisotropic microwavestructures by the method of lines

A new algorithm for the analysis of planar microwave structures with anisotropic substrates is proposed and substantiated. This algorithm is based on generalized transmission-line (GTL) equations, which are developed here for numerical algorithms. For the purpose of analysis, two different modal matrices for the discretized transverse electric and magnetic fields are calculated. Furthermore, impedance/admittance transformation formulas are developed with the help of the GTL equations for longitudinal sections and general junctions. Crossed discretization lines are used in the latter case. The materials are assumed to be biaxial or specific anisotropic. Special algorithms are developed for junctions consisting of more than two waveguides in the cross section and for bends. The proposed algorithm is verified by numerical results     

Reliability and availability analysis of an n-unit outdoor power system subject to adjustable repair facility

This paper presents a newly developed stochastic mathematical model to represent a system of n active redundant outdoor power equipment. The system considered is subject to common cause failure and adjustable repair facility. Laplace transforms of the state probabilities, system reliability and availability equations are developed. In addition, steady-state availability and mean-time-between-failures expressions are developed. The special case when n = 2 is discussed numerically.     

Use of CCD in the development of digital logic

Digital logic networks, such as OR, AND, NOT (inverters) EXCLUSIVE OR, NAND, and NOR, are developed using charge coupled devices. Operations such as digital addition; multiplication, subtraction and bit refresh are also developed by the implementation of the CCD 3-input, 2-input, and 4-input adder. Equations which will determine the responsiveness (gain) of the charge sensing amplifier are also developed. Very good correlation was obtained between experimental and theoretical characteristics of the 2-input adder, the CCD digital logic networks and the responsiveness of the charge sensing amplifier.     

混凝土嵌入式压电动态剪应力传感器研发

制作了一种利用剪切型压电陶瓷片作为传感元件的可用于混凝土内部动态剪应力测量的传感器,提出了一种标定试验方法,即将动态剪应力传感器嵌入混凝土空心薄壁空心圆筒中,并利用小型落锤试验机,对空心薄壁圆筒施加冲击荷载根据剪力计算值与传感器的输出信号对传感器灵敏度进行标定。试验结果表明,传感器输出与剪应力的线性相关性好,不同传感器之间的灵敏度个体差异小。     

A 1.8-V embedded 18-Mb DRAM macro with a 9-ns RAS access time andmemory-cell area efficiency of 33%

A 1.8-V embedded 18-Mb DRAM macro with a 9-ns row-address-strobe access time and memory-cell area efficiency of 33% has been successfully developed with a single-side interface architecture, high-speed circuit design, and low-voltage design. In the high-speed circuit design, a multiword redundancy scheme and Y-select merged sense scheme are developed to achieve the performance goal. In the low-voltage design, a dual-complement charge-pump scheme and a decoupling capacitor utilizing a tantalum-oxide capacitor are developed to retain high performance at low supply voltage     

用SEA法分析地对空雷达对抗系统的时效性

时效性分析是地对空雷达对抗系统效能评估的重要内容,本文利用SEA方法建立了一个时效性分析模型。首先建立一个干扰站的时效性分析模型,然后在此基础上进一步建立整个地对空雷达对抗系统的时效性分析模型,最后通过算例验证了模型的正确性和实用性。     

Supplementary services in the H.323 IP telephony network

Traditionally, different networks were developed to handle voice, data, and video. The circuit-switched telephone network carried voice and the packet network carried data. Due to different deployment of these networks, different services were developed, such as voice mail in the telephone network and electronic mail on the Internet. With the revolution of multimedia in the computer industry, voice, video, and data are now being carried on both networks. Supplementary services, such as transfer and forwarding (which were originally developed for private telephone networks and later migrated to public telephone networks) are now being developed for packet networks. The standards for packet networks are being defined in the H.323-based series of ITU-T recommendations. This article provides the H.323 architecture for supplementary services, the differences in deployment of these services between the circuit-switched and packet-switched networks, and interworking of these services across hybrid networks     

Boundary Conditions for the Four Vector Potential (Correspondence)

Boundary conditions describing perfectly conducting surfaces are developed for the four-component vector potential. The boundary conditions are nonunique and are shown to depend on the choice of the gauge. A physical interpretation is developed for the nonunique property. The results shown herein provide boundary conditions for the development of a computer approach to field problems in terms of the four-component vector potential.     

DEVELOPMENT OF PHOTOCONDUCTIVE SWITCH AND ITS APPLICATIONS

The picosecond photoconductive switches are developed and used to detect the pulse laser waveform. By using the photoconductive switches, an novel lab model of ultra-wide band(UWB) radar is also developed. The experimental results are given to show the performances of the switches and the UWB radar.     

Lenses and graded films for focusing and guiding acoustic surface waves

Two novel schemes for guiding acoustic surface waves along curved paths on isotropic substrates are described. One involves the deposition of a slowing film of graded thickness along the intended path on a dielectric substrate. Paraxial-ray equations are developed to describe the ray paths adjacent to the axis of the guiding film, which are determined by the slowing factor resulting from a variable-thickness deposited film. Diffraction is taken into account through an approximation developed by Pierce for optical beams. It is shown that very thin films are sufficient for a substantial amount of directional control. The other guidance system employs a series of lenses in analogy with the lens guides developed for millimeter waves and optical beams. Some comments are made about thin-film lenses and the theory is developed for the focusing action of a lens formed by a spherical depression in (or protrusion from) the surface of a substrate. A simple analog for determining ray paths over generally nonplanar surfaces is described and applied to nonspherical depressions to evaluate their focusing properties.