数字阵列收发组件FPGA远程配置的研究与实现

数字阵列雷达(DAR)正成为相控阵雷达的一个重要发展方向,数字阵列收发组件(DAM)是其核心。针对数字阵列雷达DAM模块数量众多,通常与阵列天线集成安装在舱外导致调试困难的实际情况,给出了一种数字阵列收发组件现场可编程门阵列(FPGA)远程配置的设计方法,利用Flash存储配置数据、CPLD产生配置时序和通信接口、复用系统通信光纤,较好地解决了DAM模块远程调试的难题,动态重构技术的应用极大地提高了系统的试验效率,在某数字阵列雷达演示验证项目中得到成功应用,取得了良好的效果。     

支持大数据量GML到SVG转换的XSLT优化处理器

GML是一种基于XML的标记性语言,但不支持地理数据的可视化显示,通过XSLT语言,将GML转换为W3C制定的矢量图形格式SVG,可以方便与用户的交互和地理数据的可视化显示.传统的XSLT转换处理器采用DOM的解析技术,对大数据量的GML文档处理上有很大的局限性.文中实现了一个支持大数据量GML文档的XSLT转换器GSxslt,采用SAX事件解析技术,同时优化了转换所需要的样式表文件,设计了样式表文件分类优化算法.实验证明GSxslt处理器在转换性能上较传统XSLT处理器有了很大的提高.     

Design methodologies for simulation translators (with a case study)

General design criteria for developing a software system capable of translating files from one set of simulation tools to another are discussed. The emphasis is on the data and control structures applicable in the development of such a system. The guidelines lay the foundation for the translation software. Additional design criteria may be necessary and will vary depending on the specific application. A software package that translates simulation programs (written in a language known as SALSIM) to stimulus files (written in a format known as Sentry) is presented     

Using English as a High-Level Robot Command Language

To facilitate expedient communication with robots, a very high-level hierarchical robot command language (Hirob) has been designed and implemented. Hirob uses the full and comprehensive syntax of the English imperative, allowing users to control a robot without the need of learning an esoteric programming language. A Parser/Scanner/Recognizer (PSR) performs a lexical analysis of a Hirob command stream, and identifies which portions of the command stream already exist as fully defined procedures in the files of the Procedure Management System (PMS). Those portions which do not exist must be defined using either existing Hirob procedures (English phrases), or by using the primitive commands of the low-level robot command language (Lorob). This process is fully recursive, so that Hirob procedures may consist of defined or undefined Hirob procedures, as well as Lorob commands, with the understanding that a high-level command cannot be executed until all of its hierarchical subcommands have been fully defined. A user-friendly editor has been incorporated into the PMS to allow convenient creation, modification, and testing of Hirob commands.     

Structure preserving anonymization of router configuration data

A repository of router configuration files from production networks would provide the research community with a treasure trove of data about network topologies, routing designs, and security policies. However, configuration files have been largely unobtainable precisely because they provide detailed information that could be exploited by competitors and attackers. This paper describes a method for anonymizing router configuration files by removing all information that connects the data to the identity of the underlying network, while still preserving the structure of information that makes the data valuable to networking researchers. Anonymizing configuration files has unusual requirements, including preserving relationships between elements of data, anonymizing regular expressions, and robustly coping with more than 200 versions of the configuration language. Conventional tools and techniques are poorly suited to the problem. Our anonymization method has been validated with a major carrier, earning unprivileged researchers access to the configuration files of thousands of routers in hundreds of networks. Through example analysis, we demonstrate that the anonymized data retains the key properties of the network design. The paper sets out techniques that could be used in an attempt to break the anonymization, and it concludes our anonymization techniques are most applicable to enterprise networks, because the large number of enterprises and the difficulty of probing them from the outside make it hard to recognize an anonymized network based solely on publicly-available information about its topology or configuration. When applied to backbone networks, which are few in number and many of whose properties can be publicly measured, the anonymization might be broken by fingerprinting techniques described in this paper.     

Architectures for language recognition

Two distinct chip architectures for language recognition are presented. The first allows a recogniser for any regular expression to be constructed by simply assembling predefined cells into a linear array. The cells correspond to the symbols which can occur in a regular expression, and the appropriate cells are placed in a line in the same order as the expression. The recogniser is then correct by construction, and all inter-cell connections are made automatically. The second architecture can be programmed to recognise any LL(1) context-free language by loading it with the appropriate grammer rules. The grammar rules are embodied within an array of identical cells, which, in conjunction with a standard LIFO stack, form the recognition hardware.     

High-performance BiCMOS 100 K-gate array

A BiCMOS gate array in 0.8-μm technology with CMOS intrinsic gate delays of 100 ps plus 60 ps/fan-out and BiCMOS intrinsic delays of 200 ps with a 17-ps/fan-out drive factor is discussed. A compact base cell (750 μm²/gate) has been designed with full bipolar drive capability for the efficient layout of both primitive gates and large-arrayed macros, such as register files and multipliers. A 106 K-gate array has been built on a 1.14-cm² chip with ECL I/O capability. The place and route in three levels of metal provide array utilization greater than 90%. The gate array was used to implement a 74 K-gate filter design with testability features such as JTAG and two-phase scan     

An Effective RAID Data Layout for Object-Based De-duplication Backup System

We propose an alternative Redundant array of independent disks (RAID) data layout,Asymmetrical grouping data organization (AGDO),for object-based data de-duplication backup system.Object-based data deduplication is an effective solution for detecting duplicate data for compound files.We designed an asymmetrical grouping strategy,the disk in the array are partitioned into different groups,and in each group parallelism data access scheme is adopted,different types of objects are stored in different groups with maybe different group size,it can set and manage dynamic group size by using dynamic disk group adjustment algorithms.The performance of AGDO is evaluated and proved to be sufficient for the continuous storage application.The result is that disk accesses are concentrated in a part of the disks over a long time period and reduces the power consumption to 25％ in a 10-disk configuration.Moreover,object-based de-duplication combined with AGDO has great potential in increasing data restoration speed for compound files.We have shown that this combination makes average restoration speed improved 11％.     

Pushing Dependent Data in Clients–Providers–Servers Systems

In satellite and wireless networks and in advanced traffic information systems in which the up-link bandwidth is very limited, a server broadcasts data files in a round-robin manner. The data files are provided by different providers and are accessed by many clients. The providers are independent and therefore files may share information. The clients who access these files may have different patterns of access. Some clients may wish to access more than one file at a time in any order, some clients may access one file out of of several files, and some clients may wish to access a second file only after accessing another file. The goal of the server is to order the files in a way that minimizes the access time of the clients given some a-priori knowledge of their access patterns. This paper introduces a clients–providers–servers model that better represents certain environments than the traditional clients–servers model. Then, we show that a random order of the data files performs well, independent of the specific access pattern. Our main technical contribution is de-randomizing the procedure that is based on selecting a random order. The resulting algorithm is a polynomial-time deterministic algorithm that finds an order with the same performance bounds as those of the random order.     

Fast decimal-binary conversion

A fast combinational iterative array is described which may be used, with simple additional gating, to convert data in 8421 or 2421 binary-decimal code into binary code. The array cells, which have a simple interconnection pattern, are currently available as medium-scale integration devices.     

Research on RTF array overflow vulnerability detection

When the virtual function was executed,it could cause array overflow vulnerability due to error operation of the virtual function table of C++ object.By attacking the virtual function,it could cause the system crash,or even the attacker to control the execution of program directly was allowed,which threatened user’s security seriously.In order to find and fix this potential security vulnerability as soon as possible,the technology for detecting such security vulnerability was studied.Based on the analysis of the virtual function call during the MS Word parsing RTF files,the array overflow vulnerability generated by MS Word parsing abnormal RTF files,and a new RTF array overflow vulnerability detection method based on the file structure analytical Fuzzing was proposed.Besides,an RTF array overflow vulnerability detection tool (RAVD,RTF array vulnerability detector) was designed.The test results show RAVD can detect RTF array overflow vulnerabilities correctly.Moreover,the Fuzzing results show RAVD has higher efficiency in comparison with traditional file Fuzzing tools.     

Novel Fault-Tolerant Decompression Method of Corrupted Huffman Files

Data compression and decompression have been widely applied in modern communication and data transmission fields. But how to decompress corrupted lossless compressed files is still a challenge. This paper presents a fault-tolerant decompression (FTD) method for corrupted Huffman files. It is achieved by utilizing source prior information and heuristic method. In this paper, we propose to use Huffman coding rules and grammar rules to model the source prior. According to the source prior information, we can roughly estimate the range of error bits. As for error correction, a heuristic algorithm is developed to determine the accurate positions of error bits and correct the errors. The experimental results demonstrate that the proposed FTD method can achieve a correction rate of 96.84% for corrupted Huffman files when the source prior information is accurate. More importantly, the proposed method is a general model that can be applied to decompress various types of lossless compressed files of which the original files are natural language texts.     

A software environment for digital signal-processing simulations

A signal-processing software system is described which allows the simulation of systems described by block diagrams or signal-flow graphs. A high-level data-flow language describes the interconnection of the components. All configurations of interconnections are allowed, including those containing feedback. Component systems (blocks) are allowed to be multi-input, multi-output, and to be programmed in any language. Blocks are implemented as separate processes running under a UNIX² operating system. Input and output signals are transferred between blocks via the UNIXpipe facility. Thedata type of a signal is arbitrary in the context of the compiler; within a component or system, signals and internal variables can be either floating point or fixed point. The compiler enforces strong or weak type checking of signals according to the characteristics of the blocks generating and receiving the signals. The invariance of the program to implementation data type is accomplished by the use of abstract data types. Fixed-point simulations having differing number of bits per signal and per internal variable in a block are supported. Special display software is used to allow any signal in the system to be displayed on any graphics device.This work was supported primarily by Grant MCS-8121884 from the National Science Foundation. The software system described herein may be obtained from the authors.     

New 5.8-GHz circularly polarized retrodirective rectenna arrays for wireless power transmission

This paper proposes two new circularly polarized retrodirective rectenna arrays, including a 2 /spl times/ 2 array and a 4 /spl times/ 4 array. A proximity-coupled microstrip ring antenna is used as the retrodirective rectenna array element, which can automatically block harmonic signals up to the third order from reradiating by the rectifying circuit. These arrays are printed on a Rogers Duroid 5880 substrate of /spl epsiv//sub r/=2.2 with a two-layer structure, with a total thickness of 1.5748 mm (or 62 mil). The new retrodirective rectenna array can track the incoming power source signals automatically and is less sensitive to the power incident angle variations, i.e., main-beam alignment deviation. It can provide a nearly constant dc output voltage within /spl plusmn/10/spl deg/ and 90% dc output voltage within /spl plusmn/45/spl deg/. The conversion efficiencies of the two arrays are 73.3% and 55%, respectively, when the power density is 10 mW/cm/sup 2/. The retrodirective rectenna array can be used in the low-power density applications for microwave wireless power transmissions.     

On refocusing a radio telescope to image sources in the near fieldof the antenna array

A theoretical model is developed for describing the operation of a radio telescope using techniques from optical coherence theory. This model is then used to develop a more systematic approach to the problem of refocusing a radio telescope to image sources which are within the near-field of the antenna array when the antenna array is in the far field of the source distribution. This is done by refocusing the telescope onto the sources in analogy to a photographic camera. Two methods for refocusing the telescope are described which would require no modification to most existing telescopes. In the first method, refocusing is accomplished either electronically by curving the antenna array into a portion of a hemisphere with a center at the source, or, alternatively by processing the correlation function data obtained from the antennas in a somewhat modified manner     

Spatio-temporal dynamics of gain-guided semiconductor laser arrays

A continuous model based on the coupled field-matter Maxwell-Bloch equations for a two-level homogeneously broadened single mode laser is developed. The model includes a Langevin formulation to model thermal and spontaneous emission noises and accounts for carrier diffusion, optical field diffraction and current spreading. Our model is flexible enough to simulate any gain-guided longitudinally uniform laser geometry and is applied to both a single-stripe and a four-stripe gain-guided semiconductor lasers where the influence of the injection current, the interstripe distance and carrier diffusion is discussed within the context of the laser dynamics. We show that an array operating with quasi-independent stripes may be achieved at low pumps and larger interstripe distances. However, as injection current is increased or the interstripe distance is decreased, the device passes through a variety of dynamical instabilities which can be analyzed in the context of lateral cavity modes. Moreover, we also show that the array dynamics is strongly influenced by carrier diffusion which may also lead to different thresholds for each element of the array     

LabVIEW与MATLAB混合编程在数字天线阵列测试中的应用

数字天线阵列由于其众多的优点使其在军事和民用领域都得到了广泛的应用。但是阵列系统的多天线单元和多收发通道必然带来阵列系统的误差,这些误差会影响系统的性能,所以必须对其进行校正。在虚拟仪器系统开发平台——LabVIEW上编制具有友好人机交互界面的数据采集和监视VI(虚拟仪器);利用MATLAB强大的数据处理能力进行数据分析。并通过LabVIEW调用MAT-LAB Script节点和COM组件法进行LabVIEW与MATLAB的混合编程,实现了阵列天线测试过程中的通道监视、数据采集和验证,最终完成了数字天线阵列的测试工作。     

A versatile function generator chip implemented in an I/SUP 2/L gate array

A mask-programmable I/SUP 2/L gate array is used to implement a versatile function generator chip which employs a 9 bit input data set to generate a 9 bit digital ramp. The chip utilizes a novel ripple adder design that uses only eight I/SUP 2/L inverters per full adder and requires only on I/SUP 2/L gate delay for carry propagation per bit. The ramp can wobbulate between an initial and a final frequency or have a constant frequency. The initial and final frequencies, the wobbulation rate, the ramp amplitude and frequency, and the wobbulation mode are all controlled from the input data. The output may also be selected as a rectangular wave with variable duty cycle. Typical input data setup and hold times of about 75 ns each were obtained for this design. A gate utilization factor ~95 percent has been achieved in programming the gate array.     

基于S3C6410的USB视频压缩、回放系统

阐述了在嵌入式Linux下,将市面上常见的USB摄像头作为视频输入设备,将其输出的JPEG格式图像数据通过S3C6410内部的硬件H.264编码器压缩成视频文件的方法,并基于此方法,设计了一个基于S3C6410和USB摄像头的视频采集、压缩、存储系统,采用了高级语言与汇编语言相结合的方法,在USB摄像头每秒最快输出15帧640×480图像的情况下,系统整体可以达到13 f/s(帧/秒)的录制效果。该系统具有取材方便、成本低、存储时间长、实用性强等特点。     

Automated chemistry laboratory: Application of a novel time-shared computer system

A promising strategy for providing a hospital information system is the gradual development and subsequent integration of well-defined information processing modules. A computer system which is suitable and economical to serve one or more of these modules has been developed. Its unique feature is that it uses an interpretive language for all the application programs both in the developmental and service modes of operation. The interpretive language, which has been designed specifically for data management applications, facilitates the creation and debugging of programs; in addition, it allows the time-sharing of a relatively small computer with a negligible overhead for switching control from one program to the next. The multiterminal, real-time remote-access computer system has been in service operation at the Clinical Chemistry Laboratory of the Massachusetts General Hospital since the early Fall of 1968. Presently, the system accepts typed-in requisition information, creates patient files, and generates schedules for centrifuging blood samples and for the performing of all tests; the system also accepts test results and provides reports on individual patients. In the near future all test results will be manually entered into the machine, which will then generate cumulative test reports each day. The on-line connection of automated laboratory equipment (AutoAnalyzers) will soon follow. Analysis of the system performance shows that the use of an interpretive language is suitable for this application, and it also indicates that the system has sufficient capacity for serving additional information processing needs.