基于XML的航天测控数据体制统一标准化研究

在现有传统航天测控数据处理和应用模式的基础上,提出一种基于可扩展标记语言（XML）的航天测控数据处理和应用的新体制。随着试验网络IP化改造的进一步推广,这种新的航天测控数据体制,在数据描述自定义、软件重用和模块化、标准化数据处理及网络扩展应用等方面有突出优势,在对航天测控数据处理与应用的统一标准化体制建立上具有重要意义,同时也为航天测控网统一系统及数据仓库、数据挖掘等综合应用服务平台的建立提供了新思路。     

Characterization of optimum polarization for multiple targetdiscrimination using genetic algorithms

A stochastic optimization algorithm is used to characterize the polarization states of a nonpolarimetric radar transmitter and receiver antennas for optimal target classification. Specifically, the optimized solution is sought when a multitude of targets are to be categorized. It is shown that the objective function of the optimization problem is highly nonlinear and discontinuous, hence, classical optimization algorithms fail to provide satisfactory results. The stochastic optimization algorithm used is based on a genetic algorithm (GA) which operates on a discretized form of the parameter space and searches globally for the optimum point. In this process, it is assumed that the polarimetric responses of the targets are known a priori. The optimization algorithm is applied to two sets of data: (1) a synthetic backscatter data for four point targets with similar radar cross sections (RCSs) and (2) a set of polarimetric backscatter measurements of asphalt surfaces under different physical conditions at 94 GHz. The purpose of the latter study is to come up with the optimal design for polarization states of an affordable millimeter-wave radar sensor that can assess traction of road surfaces     

航天用集成网状电缆的开发

介绍了集成网状电缆的结构特点以及产品研制过程中解决的一些主要问题。简要阐述了高科技检测设备的应用对此类电缆发展的促进作用，预测了集成网状电缆的发展前景以及在其它一些重要领域上的使用。     

Simultaneous multiple target recognition using polarization agile waves

A novel matching method for simultaneous multi-target recognition is proposed by jointly considering target’s prior scattering knowledge and the polarization parameters of radar echoes. The matching coefficients are calculated for the judgment. MATLAB simulations show that several targets can be accurately recognized simultaneously, and a high recognition probability can be achieved in Monte Carlo simulations. The total execution time can be remarkably reduced in the Field Programmable Gate Array (FPGA) implementation of the matching procedure.     

Efficient heuristics for data broadcasting on multiple channels

The problem of data broadcasting over multiple channels consists in partitioning data among channels, depending on data popularities, and then cyclically transmitting them over each channel so that the average waiting time of the clients is minimized. Such a problem is known to be polynomially time solvable for uniform length data items, while it is computationally intractable for non-uniform length data items. In this paper, two new heuristics are proposed which exploit a novel characterization of optimal solutions for the special case of two channels and data items of uniform lengths. Sub-optimal solutions for the most general case of an arbitrary number of channels and data items of non-uniform lengths are provided. The first heuristic, called Greedy+, combines the novel characterization with the known greedy approach, while the second heuristic, called Dlinear, combines the same characterization with the dynamic programming technique. Such heuristics have been tested on benchmarks whose popularities are characterized by Zipf distributions, as well as on a wider set of benchmarks. The experimental tests reveal that Dlinear finds optimal solutions almost always, requiring good running times. However, Greedy+ is faster and scales well when changes occur on the input parameters, but provides solutions which are close to the optimum. This work has been supported by ISTI-CNR under the BREW research grant. Stefano Anticaglia received the bachelor’s degree in Computer Science from the University of Perugia (Italy) in 2005. At present, he is a student in the master’s of Computer Science of the University of Perugia. Ferruccio Barsi received the doctor engineering degree from the University of Pisa, Italy, in 1969. From 1969 to 1992 he has been with he National Council of Research at the Istituto di Elaborazione dell’Informazione, Pisa. Since 1992, he is a Full Professor of Computer Science in the Mathematics and Computer Science Department of the University of Perugia, Italy. His main contributions are in the areas of computer architecture, error-control coding, systems diagnosis, VLSI design, digital signal processing, and computer graphics. He is currently involved in researches concerning network security and wireless communications. Alan Bertossi was born in London (England) in 1956. He got the Laurea Degree summa cum laude in Computer Science from the University of Pisa (Italy) in 1979. Afterwards, he worked as a System Programmer and Designer. From 1983 to 1994 he was with the University of Pisa as a Research Associate first, and later as an Associate Professor. From 1995 to 2002 he was with the University of Trento (Italy), as a Full Professor. Since 2002, he has been with the Department of Computer Science of the University of Bologna (Italy), as a Professor of Computer Science. His main research interests are the computational aspects of high-performance, parallel, VLSI, distributed, fault-tolerant, and real-time systems. He has published about 40 refereed papers on international journals, as well as several papers in international conferences, workshops, and encyclopedias. He has authored a book (on design and analysis of algorithms, in Italian) and he served as a guest coeditor for special issues of Algorithmica, Discrete Applied Mathematics, and Mobile Networks and Applications. He is a member of the editorial board of Information Processing Letters. His biography is included in the 1999 edition of Who’s Who in the World and in the 2000 edition of Who’s Who in Science and Engineering. Since 1999, he has been a scientific collaborator at the Institute of Information Sciences and Technologies of the Italian National Research Council (ISTI-CNR, Pisa, Italy). During 2001–2003, he was the national coordinator of an Italian research project on algorithms for wireless networks. Lucio Iamele received the bachelor’s degree in Computer Science from the University of Perugia (Italy) in 2004. At present, he is working at Noranet (Italy) as a system programmer and designer. M. Cristina Pinotti received the Dr. degree cum laude in Computer Science from the University of Pisa, Italy, in 1986. During 1987–1999 she was a Researcher with the National Council of Research at the Istituto di Elaborazione dell’Informazione, Pisa. From 2000–2003 she was an Associate Professor at the University of Trento. From 2004, she is a Full Professor at the University of Perugia. In 1994 and 1995 she was a Research Associate at the Department of Computers Sciences, University of North Texas, Denton, TX. In 1997 she visited the Department of Computer Science, Old Dominion University, Norfolk, VA (USA). Her research interests are in wireless networks, sensor networks, design and analysis of algorithms, data broadcasting, channel assignment problems, graph coloring, multiprocessor interconnection networks, design and analysis of parallel algorithms, parallel data structures, distributed computer arithmetic, residue number systems, VLSI special purpose architectures. She has published about 50 refereed papers on international journals, in international conferences and workshops. She has been a guest co-editor for special issues of Mobile Networks and Applications, Wireless Networks and Journal of Parallel and Distributed Computing. She is a member of the editorial board of International Journal of Parallel, Emergent and Distributed Systems.     

Velocity filters for multiple interferences in two-dimensionalgeophysical data

A procedure for the velocity filtering of two-dimensional geophysical data is discussed. This procedure involves repeatedly applying multichannel filters to a small number of overlapping subarrays of the input data. The multichannel filters can be chosen so that the resulting velocity filter is capable of suppressing multiple interferences traveling at different velocities. The two-dimensional frequency-wavenumber expression of the velocity filter is derived. With this expression, it becomes possible to implement the filter using two-dimensional fast Fourier transform (FFT) techniques. Two examples which illustrate the performance of the derived filters are presented     

Adaptive band-pass equalizer for multiple carrier data transmission

In this paper, a novel band-pass equalizer for orthogonal multiple carrier (omc) data receivers is investigated. Essentially, the band-pass equalizer consists of an fir filter preceding the receiver filter bank and processing the whole transmission band at the high input sampling rate. The coefficients of the fir equalizer are optimized iteratively in the sense of a minimum mean square error of the received and demodulated signals. A simulation of the proposed equalizer on a work-station shows that it adapts in a substantially shorter time compared to adaptive multichannel baseband equalizers at a comparable computational efficiency.     

Integrated vehicle health management for aerospace platforms

This article introduces IVHM (integrated vehicle health management) fundamentals, identifies the primary challenges that face the aerospace IVHM developer, enumerates some of the approaches that are being integrated into Boeing products, and identifies key lessons learned that can be applied to new IVHM developments. Using automobile electronic systems for comparison, the following topics are discussed: diagnostic functions; prognostic functions; automated inspections; anomaly detection; aerospace systems complexity; affordability and interoperability; system lifespan requirements; operational and maintenance environments; market implications; practical application of IVHM techniques.     

用于多个引伸计数据采集的接口电路设计

针对力学实验或生产加工的实际功能需求,以高性能单片机STC12C5410AD为核心设计开发了一套用于多个电子引伸计数据采集的电路系统。系统硬件电路以24位高精度A/D转换芯片AD7714为模数转换器件,并且运用其放大模块进行信号的放大处理;下位单片机程序采用Keil C51进行编写,系统上位机软件应用VB进行设计和开发。全套系统造价低、体积小、便携性好,能同时检测和显示1～3路形变信号,测试实验表明该系统检测精度高、实时性好,能满足力学性能实验和生产加工现场的实际功能需求,具有较大的应用价值。     

Velocity filters for multiple interference attenuation ingeophysical array data

The problem of velocity filtering a record of seismic data with the objective of extracting a desired signal by attenuating the coherent interferences traveling at different velocities is considered. A two-dimensional (N-input (N-M+1)-output) processing scheme is used where the (N-M+1) output traces are generated from the N-input traces by multichannel processing of overlapping subsets of M-input races. Each output is generated by using a vector of multichannel arrays filters designed to attenuate multiple coherent interference and random noise. The two-dimensional frequency-wavenumber expression corresponding to the proposed multiple-input-multiple-output processing scheme is derived so that it can be implemented using the two-dimensional fast Fourier transform. Two illustrative examples are included     

Equalizers for transmultiplexers in orthogonal multiple carrier data transmission

Orthogonal multiple carrier data transmission systems are efficiently realized using modified dft transmultiplexer filter banks. In data transmission applications, a non-ideal transmission channel causes distortions such as intersymbol interference and crosstalk between the subrate bands of the transmultiplexer. Hence, in order to equalize these distortions, subband equalizers, which affect the intersymbol interference and crosstalk behavior, are considered for implementation. The special structure of modified dft transmultiplexers requires a discussion concerning the various possibilities of placing the subband equalizers at the receiver. Wiener solutions and lms adaptive algorithms for various new subband equalizer structures are derived and compared by means of simulation results.     

多数据仓库集成方案的设计与实现

基于多级应用的多数据系统,为满足企业级和平台级的不同数据分析需求,采用分布式环境构建两级数据仓库。利用数据库链接实现跨数据库间的数据交互;采用夜间增量更新的数据驱动策略,控制两级数据仓库更新的数据量且减少了服务期间的通信频率;特别针对逻辑模型完整性进行讨论并给出了设计方案。通过对存储管理层进行功能测试发现,采用上述策略能够成功构建两级数据仓库并正确实现数据集成。进一步对数据集成效率进行分析,发现在数据量较少的情况下采用表分区技术能够减少数据集成的时间开销约达45%。     

A wave polarization converter for circular polarization

A linearly polarized wave may be converted to a circularly polarized wave by means of a panel which provides90degdifference in transmission phase between two crossed linear components. This phase difference is obtained over a wide frequency band by means of thin sheets containing both inductive and capacitive shunt susceptance. Low reflection and near unity axial ratio may be obtained by means of three sheets which are spaced for least reflection. An experimental polarizer has been constructed using three photo-etched sheets and a dielectric honeycomb core. Over a 20 per cent band the axial ratio of the circular polarization is within 1.7 db and the insertion loss is within 0.5 db. Over a 46 per cent band the axial ratio is less than 2.0 db and the insertion loss is less than 1.0 db.     

The analysis of multiple signal data

This paper discusses the automatic processing of data containing multiple signals. In particular, filters which modify their structures in order to recognize initially unknown waveforms in Gaussian noise and an unknown signal environment are investigated experimentally. The general structure, derived from decision theory, processes the data in nonlinear fashion and effectively sets up a narrow decision region about the estimate of the signal. The results demonstrate the possibility of using filters of the new type for automatically processing data although the relevant waveforms may be unknown {em a priori}.     

A generalized probabilistic data association detector for multiple antenna systems

The Probabilistic Data Association (PDA) method for multiuser detection (MUD) over synchronous CDMA channels is extended to the signal detection problem in V-BLAST systems. Computer simulations show that the algorithm has an error probability that is significantly lower than that of the V-BLAST optimal order detector and has a computational complexity that is cubic in the number of transmit antennas.     

航天高稳激光源温控电路设计

从航天实际应用角度出发,提出了基于MAX1968芯片的高稳激光源自动温控系统设计方法,介绍设计电路工作原理和组成的同时,给出了关键使用技术优化方案.结合某型号航天项目的具体测试,结果表明该温控电路在实际应用中能够达到双向无死区温控和0.01℃温度稳定性的要求.     

Ball grid array reliability assessment for aerospace applications

Reliability of ball grid arrays (BGAs) was evaluated with special emphasis on space applications. This work was performed as part of a consortium led by the Jet Propulsion Laboratory (JPL) to help build the infrastructure necessary for implementing this technology. Nearly 200 test vehicles, each with four package types, were assembled and tested using an experiment design. The most critical variables incorporated in this experiment were package type, board material, surface finish, solder volume, and environmental condition. The packages used for this experiment were commercially available packages with over 250 I/Os including both plastic and ceramic BGA packages.The test vehicles were subjected to thermal and dynamic environments representative of aerospace applications. Two different thermal cycling conditions were used, the JPL cycle ranged from −30°C to 100°C and the Boeing cycle ranged from −55°C to 125°C. The test vehicles were monitored continuously to detect electrical failure and their failure mechanisms were characterized. They were removed periodically for optical inspection, scanning electron microscopy (SEM) evaluation, and cross-sectioning for crack propagation mapping. Data collected from both facilities were analyzed and fitted to distributions using the Weibull distribution and Coffin–Manson relationships for failure projection. This paper will describe experiment results as well as those analyses.     

Fusing multiple data and knowledge sources for signal understandingby genetic algorithm

This paper presents a new approach to partially automating a human expert's proficient interpretation skills for data and knowledge fusion in signal-understanding tasks. The authors start by recognizing the fact that signal interpretation is attributed much to a human expert's domain-specific, pattern-perceiving capability of grasping raw signals by structured representations having multiple levels of abstraction, rather than to some objectively defined knowledge. In other words, that is an emergent or self-organizing process, where information is regarded as perceptual as opposed to objectively defined. First, they attempt to organize such structured representations by usage of a hierarchical clustering method of data analysis. Then, based on these representations they model a human expert's interpretation skill as an activity of searching for an optimum combination of those perceptual units within that structured representation space being constrained by the data. In order to implement this activity, they introduce a genetic algorithm and apply it to the structured representation space assimilating a human analyst's creative interpreting task in flexibly shifting the focal view of attention from the coarse to the precise. They implement a working system for signal understanding of the remote sensing data of seismic prospecting and show the results output by the system