65nm工艺大容量2W/8R高速SDP存储器的设计

SDP是为"飞腾-迈创"DSP在65nm工艺下设计的一个核间数据共享存储器,容量为512×32b,端口数为2W/8R.针对SDP存储器写端口数少的特点,为减小面积,采用了分为4个2W/2R存储体的实现策略.为了提高存储单元的噪声容限,设计了读写端口分离的12管2W/2R存储单元,使得读写操作的噪声容限分别达到了333mV和274.7mV.采用层次式位线技术,提高了读写操作的速度,并降低了功耗.用全定制方法完成了2W/2R存储体的版图设计,并用Encounter完成了SDP存储器的总体集成.版图后的模拟结果显示,SS条件下的最大延时为750ps,TT条件下的功耗为45.2mW@500MHz.     

L2 vector median filters on arrays with reconfigurableoptical buses

In spite of their good filtering characteristics for vector-valued image processing, the usability of vector median filters is limited by their high computational complexity. Given an N × N image and a W × W window, the computational complexity of vector median filter is O(W⁴N²). In this paper, we design three fast and efficient parallel algorithms for vector median filtering based on the 2-norm (L₂) on the arrays with reconfigurable optical buses (AROB). For 1 ⩽ p ⩽ W ⩽ q ⩽ N, our algorithms run in O(W⁴ log W/p⁴), O(W²N²/p ⁴q² log W) and O(1) times using p⁴N² / log W, p⁴q² / log W, and W⁴N² log N processors, respectively. In the sense of the product of time and the number of processors used, the first two results are cost optimal and the last one is time optimal     

基于中间件的信息系统安全解决方案

C／S结构与B／S结构各有优缺点,怎样结合B／S与C／S结构是开发MIS（Management Information System）普遍关注的问题。在实际应用中,两种结构的有机结合,可以扬长避短,有效地发挥了各自的优势。随着信息系统规模的不断扩大和互联网技术的发展,多层体系结构B／W／S／S、C／S／S应运而生,同时,B／W／S／S与C／S／S混合结构下信息系统的安全性也受到威胁。在综合分析了B／W／S／S和C／S／S混合结构信息系统模式的基础上,提出了一种基于中间件的C／S／S与B／W／S／S混合模型的MIS安全解决方案。     

Process-dependent thin-film thermal conductivities for thermal CMOSMEMS

The thermal conductivities κ of the dielectric and conducting thin films of three commercial CMOS processes were determined in the temperature range from 120 to 400 K. The measurements were performed using micromachined heatable test structures containing the layers to be characterized. The κ values of thermally grown silicon oxides are reduced from bulk fused silica by roughly 20%. The κ of phosphosilicate and borophosphosilicate glasses are 0.94±0.08 W m^-1 K^-1 and 1.18±0.06 W m^-1 K^-1, respectively, at 300 K. A plasma-enhanced chemical-vapor-deposition silicon-nitride layer has a thermal conductivity of 2.23±0.12 W m^-1 K^-1 at 300 K. This value is between published data for atmospheric-pressure CVD and low-pressure CVD nitrides. For the metal layers, we found thermal conductivities between 167 W m^-1 K^-1 and 206 W m ^-1 K^-1, respectively, at 300 K, to be compared with 238 W m^-1 K^-1 of bulk aluminum. The temperature-dependent product κρ of κ with the electrical resistivity ρ agrees better than 8.2% between 180-400 K with that of pure bulk aluminum. The κ values of the polysilicon layers are between 22.4 W m^-1 K^-1 and 37.3 W m^-1 K^-1 at 300 K. They are reduced from similarly doped bulk silicon by factors of between 2.0-1.3. The observed discrepancies between thin film and bulk data demonstrate the importance of determining the process-dependent thermal conductivities of CMOS thin films     

用植物病毒载体表达小球状病毒抗原蛋白的研究

将引起人类腹泻主要病原物小球状病毒(Small round structured virus;SRSV)编码抗原蛋白基因的全长序列1605bp,导入来自三叶草黄脉病毒(Clover yellow vein virus;ClYVV)侵染性全长cDNA克隆的侵染性植物病毒表达载体pClYVV/CP/W基因组的NIb/CP基因之间,构建了重组病毒克隆pClYVV-NV1.6。用上述重组病毒克隆接种蚕豆植物,表现了与野生型ClYVV相同的症状。从发病叶中提取总RNA,用反转录PCR(RT-PCR)对上述重组病毒克隆的转录进行了检测,结果表明,外源基因在F4子代病毒基因组中仍然稳定存在。从发病叶中提取总蛋白,用酶联免疫吸附分析(Enzyme-linked immunosorbent assay;ELISA)及蛋白质杂交(Western blotting;WB)对上述重组病毒克隆表达的目的基因产物抗原蛋白进行了测定,结果表明,重组病毒克隆pClYVV-NV1.6之目的基因产物的表达量随寄主植物发病后时间的推移而变化,最大表达是在寄主植物发病后第9天,最大表达量为每克鲜叶可表达160.00μg,这一研究结果为用植物生产抗SRSV口服疫苗提供了有力的基础。     

Open-loop and feedback-controlled mouse cursor movements in linear paths

Path length (A), path width (W) and movement direction (θ) are identified as the main factors affecting visually-controlled movement times in linear paths. Effects of A and W are well described by Drury's ( 1971 . Movements with lateral constraint. Ergonomics, l4 (2), 293-305.) model in which movement time is linearly related to the ratio of A/W. At low A/W values, departure from linearity has been identified but not investigated in detail. Data are presented for both open-loop and feedback-controlled movements in linear paths at 0, 60 and 150° movement directions. Movement amplitude and path width were varied over a wide range to determine the effects of A and (A/W) on movement time. Movements were found to be made ballistically or in open-loop mode when the ratio (A/W) was less than about 8 to 10 and the movement times were linearly related to √A for all angles of movement. Feedback-controlled movements followed Drury's law; ballistic movements had movement speed linear with √A. PRACTITIONER SUMMARY: Many tasks require manoeuvring equipment or devices through a path of limited width. These movements can be made with or without feedback control, depending on the path constraints. The conditions for the two forms of movement are determined in this research.     

W5100在FPGA系统中实现TCP／IP网络通信

介绍了W5100在现场可编程门阵列（FPGA）系统中实现TCP／IP网络通信的方法。描述了WS100的内部架构和寄存器设置,设计了一套基于直接总线接口模式的FPGA系统,系统主要由FPGA、W5100及网络接口组成。FPGA通过状态机状态控制W5100,实现传输控制协议（TCP）／互联网协议（IP）。     

Comments on Bechtel, “Levels of description and explanation in cognitive science”

I begin by tracing some of the confusions regarding levels and reduction to a failure to distinguish two different principles according to which theories can be viewed as hierarchically arranged — epistemic authority and ontological constitution. I then argue that the notion of levels relevant to the debate between symbolic and connectionist paradigms of mental activity answers to neither of these models, but is rather correlative to the hierarchy of functional decompositions of cognitive tasks characteristic of homuncular functionalism. Finally, I suggest that the incommensurability of the intentional and extensional vocabularies constitutes a strongprima facie reason to conclude that there is little likelihood of filling in the story of Bechtel's missing level in such a way as to bridge the gap between such homuncular functionalism and his own model of mechanistic explanation.     

Java应用中的汉字乱码问题分析

根据Java应用中乱码出现的原因将问题分成了4类:由于编译不当导致的乱码、Web应用中的乱码、数据库读写中的乱码和I/O读写中的乱码。在各个类别中,先给出出现乱码时的现象,然后对现象进行原因分析,再给出解决的办法。最后,根据做项目的实践经验,给出了一些解决汉字乱码问题的心得。     

Performance models and dynamic characteristics analysis for HDFS write and read operations: A systematic view

Hadoop has emerged as a successful framework for large-scale data-intensive computing applications. However, there is no research on performance models for the Hadoop Distributed File System (HDFS). Due to the complexity of HDFS and the difficulty of modeling the multiple impact factors for HDFS performance, to establish HDFS performance models based directly on these impact factors is very complicated. In this paper, the relationship between file size and HDFS Write/Read (denoted as W/R for short) throughput, i.e., the average flow rate of a HDFS W/R operation, is studied to build HDFS performance models from a systematic view. Based on the measured data of specially designed experiments (in which HDFS W/R operations can be viewed as single-input single-output systems), a system identification-based approach is applied to construct performance models for HDFS W/R operations under different conditions. Furthermore, dynamic characteristics metrics for HDFS performance are defined, and based on the identified performance models and these metrics, the dynamic characteristics of HDFS W/R operations, such as steady state and overshoot, are studied, and the relationships between impact factors and dynamic characteristics are analyzed. These analysis results can provide effective guidance and implications for the design and configuration of HDFS and Hadoop-based applications.     

10W CW broadband balanced limiter/LNA fabricated using MSAG MESFET process

This article presents the design and test data for a 10W broadband balanced limiter/LNA MMIC fabricated using MSAG MESFET process. The limiter is based on Schottky diodes and the two‐stage LNA is designed using high‐performance MESFETs. The typical measured performance for the limiter/LNA circuit includes gain greater than 14 dB, NF less than 2.7 dB, and return loss better than 20 dB over the 8.5–11.5 GHz frequency range. The CW power handling for the packaged limiter/LNA circuits was greater than 10W. The packaged devices were also exposed to power levels greater than 10W, and no catastrophic failures were observed up to 18W. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 118–127, 2003.     

基于W5100芯片的网络通信电路设计

W5100芯片是一种高集成度的网络接口芯片,内部集成有10/100M以太网控制器,经过简单的接口操作,可以实现没有操作系统的internet连接,主要应用于成本较低、稳定性较高的嵌入式系统中。本文介绍了W5100的内部构成、引脚分布、接口方式及硬件电路设计。     

面向内存访问性能优化的总线仲裁方法

访存交易的处理顺序对内存访问的性能有重要影响.同一个SoC设备发出的多个未决交易往往地址连续且读写类型相同.然而,传统的总线仲裁方法导致各个设备发出的未决交易序列交错地发送至内存控制器,而内存控制器访存调度的范围有限,最终导致此类序列通常无法连续地访问内存.为解决此问题,提出一种新型的总线仲裁方法CGH,该方法利用SoC设备通信行为的特征,通过识别同一个SoC设备发出的、行地址和读写类型相同的未决交易序列并让其连续获得仲裁授权,减少内存切换行地址和读写类型的次数;同时,在选择将要授权的未决交易序列时,优先考虑行地址和读写类型与最近授权交易相同的申请,进一步提高访存效率.将CGH仲裁方法应用至北大众志-SKSoC后,系统访存性能提高了21.37%,而总线面积仅增加2.83%.此外,由于行地址切换次数减少,内存的能耗也降低了15.15%.     

Grid-Computing

Grid-Computing, ein Mitte der 90er-Jahre eingeführter Begriff [1,2], bezeichnet eine Architektur für verteilte Systeme, die auf dem World Wide Web aufbaut und die Web-Vision erweitert. Mit dem Grid-Computing werden die Ressourcen einer Gemeinschaft, einer so genannten virtuellen Organisation, integriert. Die Hoffnung ist, dass hierdurch rechen- und/oder datenintensiven Aufgaben, die eine einzelne Organisation nicht lösen kann, handhabbar werden. Ein Grid bezeichnet eine nach dem Grid-Computing-Ansatz aufgebaute Rechner-, Netzwerk- und Software-Infrastruktur zur Teilung von Ressourcen mit dem Ziel, die Aufgaben einer virtuellen Organisation zu erledigen.     

W-stability and local input-output stability results

A new type of input-output stability is defined, based on the use of a Sobolev space W; W is well suited, like the Lebesgue space L₂ , to obtain stability characterizations in the time and frequency domains. Moreover, if compared with L₂, W has additional properties which enable one to establish “local” stability results. A local version of the small gain theorem is established in this framework, as well as some consequences of this result, in particular local versions of the passivity theorem and of the circle criterion. The relationship between “W-stability” and asymptotic stability is studied