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1.
近两个月来,本刊网站的论坛里又不太安静。有个叫"高清迷"的香港网友遭到了广东一些网友的质疑。彼此论战的焦点大部分在说香港电视好看或不好看。"高清迷"网友说大陆电视越来越好,水平已经超过香港的电视节目。广东网友们则是缅怀香港电视的辉煌历史。这原本是简单的我说你好你说我好,互相捧场的事情,但是网络的奇妙性在于事情并没有朝积极的方向发展,其结果是吵架不可避免的发生了。外来的和尚是不是会念经,我们先不去管他。重要的是我们要弄清楚自己是怎么回事。本文,是专业电视人对我国各省卫视台做的调查评估。让我们了解一下我国的电视台的现状吧。  相似文献   

2.
李晓延 《今日电子》2007,(5):126-127
2007年3月21日~23日的上海新国际博览中心是格外的热闹,超过2万名来自电子行业的专业观众汇聚与此.吸引他们来到这里的原因就是慕尼黑上海电子展,慕尼黑上海激光、光电展(LASER. World of Photonics China)、中国国际半导体设备、材料、生产和服务展览暨研讨会(SEMICON China),以及中国国际电子电路展览会(CPCA Show)四大电子业权威品牌展联合在此举行.  相似文献   

3.
ADSL服务     
现在使用ADSL上宽带网的用户是越来越多了,对ADSL设备的维护也成了一个不容忽视的问题.只有维护保养好它,不但让你的"宽带之旅"省心又省力,还能延长其寿命.ADSL的维护可分为软件和硬件两个方面来分析,软件主要是PPPOE协议的问题,和计算机本身的气操作系统,和网卡方面的事情.硬件主要是局端的节点设备,和用户端猫的问题.还有通信的线路等一些因素.  相似文献   

4.
命题逻辑是一个以命题为基本研究对象的数学化的逻辑系统,命题逻辑是数理逻辑的基础,也是计算机科学与技术的理论基础.为了深入理解命题逻辑,将命题逻辑与一般的代数学进行比较,从6个方面简要总结和论述命题逻辑中代数学的一些思想和方法,使得读者能从中体会到代数学的一些思想和方法在命题逻辑中的应用.  相似文献   

5.
袁坤 《IT时代周刊》2007,(22):20-20
11月1日,似乎是个好日子!来自英特尔、EMC、思科的3位跨国公司CEO均选在这一天访华,并宣布其在中国市场大手笔的战略投入. 11月2日,来自全球最大显卡芯片厂商NVIDIA公司的联合创始人、总裁兼CEO黄仁勋借访华之际,在清华大学美术学院报告厅进行了"GPU--还原一个真世界"的演讲.  相似文献   

6.
引言 热插拔(hot swapping)的定义是从一块正在通电运作中的背板(backplane)上插入或移除电路板.这项技术被广泛应用在电信服务器(telecom servers)、USB界面、火线(firewire)界面和 CompactPCI应用等[参考1].这种技术可在维持系统背板的电压下,更换发生故障的电路板,而同时系统中其它正常的电路板仍可保持运作.  相似文献   

7.
Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the focus of many initiatives. Effectively analyzing massive network security data with high dimensions for suspicious flow diagnosis is a huge challenge. In addition, the uneven distribution of network traffic does not fully reflect the differences of class sample features, resulting in the low accuracy of attack detection. To solve these problems, a novel approach called the fuzzy entropy weighted natural nearest neighbor(FEW-NNN) method is proposed to enhance the accuracy and efficiency of flowbased network traffic attack detection. First, the FEW-NNN method uses the Fisher score and deep graph feature learning algorithm to remove unimportant features and reduce the data dimension. Then, according to the proposed natural nearest neighbor searching algorithm(NNN_Searching), the density of data points, each class center and the smallest enclosing sphere radius are determined correspondingly. Finally, a fuzzy entropy weighted KNN classification method based on affinity is proposed, which mainly includes the following three steps: 1、 the feature weights of samples are calculated based on fuzzy entropy values, 2、 the fuzzy memberships of samples are determined based on affinity among samples, and 3、 K-neighbors are selected according to the class-conditional weighted Euclidean distance, the fuzzy membership value of the testing sample is calculated based on the membership of k-neighbors, and then all testing samples are classified according to the fuzzy membership value of the samples belonging to each class;that is, the attack type is determined. The method has been applied to the problem of attack detection and validated based on the famous KDD99 and CICIDS-2017 datasets. From the experimental results shown in this paper, it is observed that the FEW-NNN method improves the accuracy and efficiency of flow-based network traffic attack detection.  相似文献   

8.
追日     
去年10月一个温暖的早晨,在澳大利亚内陆深处,14名麻省理工学院的学生和校友上午6点就爬出了他们的睡袋,准备车队,进行又一天的艰苦驾驶,在护卫队的护送下,他们驶过一段平坦、笔直、炎热、灰尘弥漫的道路.领头的车辆迎着其他车流,形成了一个缓冲带,一辆货车断后以监测整个队伍的进程.  相似文献   

9.
The diode infrared focal plane array uses the silicon diodes as a sensitive device for infrared signal measurement. By the infrared radiation, the infrared focal plane can produces small voltage signals. For the traditional readout circuit structures are designed to process current signals, they cannot be applied to it. In this paper,a new readout circuit for the diode un-cooled infrared focal plane array is developed. The principle of detector array signal readout and small signal amplification is given in detail. The readout circuit is designed and simulated by using the Central Semiconductor Manufacturing Corporation (CSMC) 0.5 μm complementary metal-oxide-semiconductor transistor (CMOS) technology library. Cadence Spectre simulation results show that the scheme can be applied to the CMOS readout integrated circuit (ROIC) with a larger array, such as 320×240 size array.  相似文献   

10.
2007年的元旦前,业界对商品化"中国芯"的最后一丝担忧得到了舒缓. 12月27日,神州龙芯集成电路设计有限公司对外公布,中科院计算所已选择与欧洲最大的半导体公司意法半导体,将就龙芯2E的生产和销售展开合作.双方合作细节至今未见披露,但知情人士向透露,双方已经达成初步意向,即意法半导体将出资3000万元购买龙芯2E处理器5年产销权,在此期间,这家法国公司每销售一枚处理器将向北京神州龙芯公司提交2美元的专利许可费.中科院计算所所长李国杰向证实,正式确认合作的时刻将等到今年3月,届时双方将齐聚人民大会堂公布合作详情.  相似文献   

11.
A doping system consisting of NPB and PVK is employed as a composite hole transporting layer (CHTL). By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK : NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK : NPB at 1:3.  相似文献   

12.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

13.
Due to variable symbol length of digital pulse interval modulation(DPIM), it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation(FDPIM) method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.  相似文献   

14.
电磁兼容测试结果与检测实验室可靠性程度直接相关,检测实验室自身质量是保证电磁兼容测试结果准确性先决条件,检测实验室测试系统相符性则成为电磁兼容系统性能评估中需要考虑的关键内容和重要指标。因此,检测实验室测试系统相符性比对是实现电磁兼容系统评估研究的基础工作之一。本文首先针对电磁兼容检测实验室测试系统相符性比对的特点,结合自己几年来的测试实践论述了电磁兼容检测实验室测试系统相符性对比方案,然后提出了具体的案例同时进行了详细的分析,最后总结出了影响电磁兼容检测实验室测试系统相符性因素,整个案例和分析过程及结果可作为电磁兼容检测实验室测试系统相符性比对的手段和依据,具有重要的现实指导意义。  相似文献   

15.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

16.
Towards Mobile Ubiquitous Service Environment   总被引:2,自引:0,他引:2  
In this article we present a perspective on future vision of mobile communications and services which is referred to as Mobile Ubiquitous Service Environment (MUSE). Based on analysis of wireless communications and services, we exploit a conceptual model for MUSE via a top-down approach. The conceptual model consists of three major elements: Terminal Service Environment (TSE), Network Service Environment (NSE) and User Identity (UID). The concept of Always the Best Experience (ABE) is addressed as the hinge in design and development such that the user-centric services could be provided automatically and intelligently in the future diverse wireless world Based on these, we further discuss the issues on design and implementation of architecture of future wireless communication system. Requirements for architecture brought by the new features of MUSE are listed. Moreover, we also address several tradeoffs that should be taken into consideration in design. Finally, the deployment challenges for MUSE, such as reflectiveness of system, security and privacy, as well as peer-to-peer AAA are predicted.Ji Yang received PhD degree on Circuit and System, Bachelor degree on Telecommunication Engineering from Beijing University of Posts and Telecommunications (BUPT) in 2002 and 1993 respectively. Currently, he is an associate professor of BUPT, chief technical supervisor of Wireless Technology Innovation Institute, and vice manager of MTlab of Sino-Germany Software Institute. He leads the research on service and application in Future Forum in China. He also made much contribution to the China Communication Standardization Association (CCSA), including the vision of future Mobile Ubiquitous Service Environment, architecture of future B3G mobile terminal, etc. His research interests include architecture design for mobile ubiquitous networks, theory of self-organization, etc.Zhang Ping is now the professor of Beijing University of Posts and Telecommunications and director of Wireless Technology Innovation (WTI) Institute, BUPT. He has also served on the senior member of C3G Group, China MOST 863 future mobile communication FuTURE project, vice-chairman of China FuTURE Forum, and member of Vision Committee of World Wireless Research Forum(WWRF), he was vice chair of WWRF in 2005. He is also invited as the consultants for many domestic and oversea communication companies. He is very active on the international research activity on Beyond 3G area. He also participated in several European projects such as E2R and MOCCA. Until now, he has published 6 books, around 400 publications in journals and conferences in the area of telecommunications. His main research interests are theory and applications in wireless communication area. He was awarded by government, city of Beijing and Ministry of Information Industry several times for his great contribution to the industry and research activity in China.Hu Zheng is a PH.D candidate in mobile communications engineering in Wireless Technology Innovation Institute (WTI) at Beijing University of Posts and Telecommunications (BUPT). He received B.S degree from Nanjing University of Posts and Telecommunications in 2002, majoring in computer communications engineering. He currently works on serivce aspects of mobile ubiquitous communication system with focus on design and performance evaluation of interaction protocols and services in self-organized service environment.Wang Xu received the B.Tech. degree in electronic engineering from Beijing Polytechnic University (now named as Beijing University of Technology), Beijing, China, in 2002. Now he is working for his Ph.D. degree in Wireless Technology Innovation (WTI) Institute, Beijing University of Posts and Telecommunications (BUPT). His current interests include wireless communications in personal area, ad hoc networks and peer-to-peer system.Li Yinong received the BS degree major in Telecommunication Engineering in 1993 from Beijing University of Posts and Telecommunications, the MS degree and PhD degree major in Telecommunication and Electronic System in 1995 and 2003 from the Beijing University of Posts and Telecommunications. He is currently a lecture of STE (School of Telecommunication Engineering) of BUPT. His main research interests include service modeling, service composition approach, and intelligent service. In BUPT, he has given several lectures to both graduate and undergraduate students such as Information Theory, Speech Recognition, Pattern Recognition and Artificial Intelligence.  相似文献   

17.
This paper presents a unified treatment of various important signal processing techniques for the extraction of the instantaneous envelope and phase of a real signal. These techniques include Complex Demodulation, Hilbert Transformation, In-Phase and In-Quadrature Filtering, Phase-Locked Loop Demodulation, and Peak Amplitude and Zero-Crossing Detection. The salient points in the mathematical theory and implementation of these techniques are outlined, as well as their interrelationships via the theory of analytic signals. The advantages and limitations of each of these techniques are elaborated upon, and Complex Demodulation is shown to be the most effective and flexible method from an implementation point of view. The relation of the above techniques to Fourier spectrum analysis is elucidated, and an example is presented of applying Complex Demodulation for the quantification of time nonstationarities in the electrographic morphology of an EEG waveform.  相似文献   

18.
Abstact  In this paper we discuss thin-film electrical resistors utilizing granular films of the type (Co,Ni)-(Al,Si)-O and their electrical resistive properties. Resistive properties of the granular film resistors drastically change with metal content and after annealing at 450°C. The values of temperature coefficient of resistance (TCR) in the optimum metal content of the granular films were as low as those of conventional metallic alloy film resistors. The values of sheet resistance were much higher than those of conventional metallic alloy resistors. Therefore, granular films are useful for application to thin-film resistors with the goal of miniaturizing them.  相似文献   

19.
In general, there are several many devices that can overload the network and reduce performance. Devices can minimize interference and optimize bandwidth usage by using directional antennas and by avoiding overlapping communication ranges. In addition, devices need to carefully manage their use of resources, such as bandwidth and energy. Bandwidth is limited in wireless personal area networks (WPANs), so devices need to carefully select which data to send and receive. In this paper, an intelligent performance analysis of energy-efficient resource optimization model has been proposed for device-to-device (D2D) communication in fifth-generation (5G) WPAN. The proposed energy-efficient resource allocation in D2D communication is important because it helps reduce energy consumption and extend the lifespan of devices that are communicating with each other. By allocating resources in an efficient manner, communication between two devices can be optimized for maximum efficiency. This helps reduce the amount of energy needed to power the communication, as well as the amount of energy needed to power the device that is communicating with another device. Additionally, efficient resource allocation helps reduce the overall cost of communication, as the use of fewer resources results in a lower overall cost. The proposed efficient resource allocation helps reduce the environmental impact of communication, as less energy is used for communication. The proposed energy-efficient resource allocation model (EERAM) has reached 92.97% of energy allocation, 88.72% of power allocation, 87.79% of bandwidth allocation, 87.93% of spectrum allocation, 88.43% of channel allocation, 25.47% of end-to-end delay, 94.33% of network data speed, and 90.99% of network throughput.  相似文献   

20.
郭勇 《电子科技》2005,(7):57-60,64
对于下一代网络(NGN),如何保障端到端的服务质量(QoS)是NGN的核心问题之一,直接影响着NGN业务的提供.该文给出了NGN的网络体系结构和业务特点,针对其对服务质量的要求,探讨了在NGN中实现QoS的框架模型,着重介绍了几种实现端到端QoS保障的关键技术,分析了它们各自的特点和存在的问题.  相似文献   

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