检索结果-内蒙古大学图书馆

Terahertz Semiconductor Quantum Well Devices

Journal of Semiconductors 2006年第4期27卷 627-634页

作者： Liu H C Luo H Ban D Waichter M Song C Y Wasilewski Z R Buchanan M Aers G C SpringThorpe A J Cao J C Feng S L Williams B S Hu Q Institute for Microstructural Sciences National Research Council Ottawa K1A 0R6 Canada State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese AcademyofSciences Shanghai 200050 China Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA

For eventually providing terahertz science with compact and convenient devices,terahertz (1～10THz) quantum-well photodetectors and quantum-cascade lasers are *** design and projected detector performance are presented together with experimental results for several test devices,all working at photon energies below and around optical *** limited infrared performance (BLIP) operations are observed for all samples (three in total),designed for different *** temperatures of 17,13,and 12K are achieved for peak detection frequencies of 9.7THz(31μm),5.4THz(56μm),and 3.2THz(93μm),respectively.A set of THz quantum-cascade lasers with identical device parameters except for doping concentration is *** δ-doping density for each period varies from 3.2×1010 to 4.8×*** observe that the lasing threshold current density increases monotonically with doping ***,the measurements for devices with different cavity lengths provide evidence that the free carrier absorption causes the waveguide loss also to increase *** the observed maximum lasing temperature is best at a doping density of 3.6×1010cm-2.

关键词：半导体量子论激光技术光电探测器

来源：评论

学校读者我要写书评

暂无评论

Efficient Test-Data Compression for IP Cores Using Multilevel Huffman Coding 06

Efficient Test-Data Compression for IP Cores Using Multileve...

引用

Design, Automation and Test in Europe Conference and Exhibition

作者： X. Kavousianos E. Kalligeros D. Nikolos Computer Science Department University of Ioannina (UoI) Ioannina Greece Computer Engineering & Informatics Department University of Patras Patras Greece Research Academic Computer Technology Institute Patras Greece

ISBN: (纸本)9783981080100

In this paper we introduce a new test-data compression method for IP cores with unknown structure. The proposed method encodes the test data provided by the core vendor using a new, very effective compression scheme based on multilevel Huffman coding. Specifically, three different kinds of information are compressed using the same Huffman code, and thus significant test data reductions are achieved. A simple architecture is proposed for decoding on-chip the compressed data. Its hardware overhead is very low and comparable to that of the most efficient methods in the literature. Additionally, the proposed technique offers increased probability of detection of unmodeled faults since the majority of the unknown values of the test set are replaced by pseudorandom data generated by an LFSR.

关键词： Huffman coding System testing Hardware Decoding Performance evaluation Educational programs Logic informatics Fault detection Time to market

来源：评论

学校读者我要写书评

暂无评论

Distribution and partitioning techniques for NVEs: the case of EVE

Distribution and partitioning techniques for NVEs: the case ...

引用

International Workshop on Challenges of Large Applications in Distributed Environments

作者： C. Bouras E. Giannaka A. Panagopoulos T. Tsiatsos Computer Engineer and Informatics Department University of Patras Greece Research Academic Computer Technology Institute Patras Greece Computer Science Department Stony Brook University New York USA

The majority of the systems and platforms developed for supporting distributed virtual environments are based on the concept of distribution from the early beginning of their development. In this paper we present the migration to a distributed virtual environment from a traditional client-server architecture. In particular, this paper describes the case of EVE, a networked virtual environment originally aimed to support small-scale applications. EVE started as a standard client-multi server architecture, which could support multiple concurrent virtual worlds with a maximum number of seventeen simultaneous participants in each of these worlds. However, the need to support larger-scale applications revealed that the traditional architecture, upon which EVE was based, is insufficient to meet the needs of these applications, which are large both in the sense of virtual space and graphics and in regard to the number of concurrent participants. This paper discusses the migration of EVE to a distributed platform, which is able to support large-scale networked virtual environments. In particular, the paper describes the modifications realized in the architectural model of the initial platform for supporting effectively large-scale applications. The basic entities of the distributed model are presented, their operations, as well as the interconnection among them. In addition, the paper presents an initial approach of the algorithm that is adopted for the efficient partitioning of the virtual world and the assignment of the clients to the entities and resources of the distributed platform. The approach presented is space-object driven, in the sense that both the actual size of the virtual space along with the number of objects with which the user can interact is taken into account during the partitioning

关键词： computer aided software engineering Virtual environment Large-scale systems Graphics Space technology informatics Protocols Network servers Partitioning algorithms computer science

来源：评论

学校读者我要写书评

暂无评论

The Power of the Defender

The Power of the Defender

引用

International Conference on Distributed Computing Systems Workshop

作者： M. Gelastou M. Mavronicolas V. Papadopoulou A. Philippou P. Spirakis Department of Computer Science University of Cyprus Nicosia Cyprus Department of Computer Engineering and Informatics University of Patras Patras Greece Greece and Research and Academic Computer Technology Institute Patras Greece

We consider a security problem on a distributed network. We assume a network whose nodes are vulnerable to infection by threats (e.g. viruses), the attackers. A system security software, the defender, is available in the system. However, due to the network’s size, economic and performance reasons, it is capable to provide safety, i.e. clean nodes from the possible presence of attackers, only to a limited part of it. The objective of the defender is to place itself in such a way as to maximize the number of attackers caught, while each attacker aims not to be caught. In [7], a basic case of this problem was modeled as a non-cooperative game, called the Edge model. There, the defender could protect a single link of the network. Here, we consider a more general case of the problem where the defender is able to scan and protect a set of k links of the network, which we call the Tuple model. It is natural to expect that this increased power of the defender should result in a better quality of protection for the network. Ideally, this would be achieved at little expense on the existence and complexity of Nash equilibria (profiles where no entity can improve its local objective unilaterally by switching placements on the network). In this paper we study pure and mixed Nash equilibria in the model. In particular, we propose algorithms for computing such equilibria in polynomial time and we provide a polynomial-time transformation of a special class of Nash equilibria, called matching equilibria, between the Edge model and the Tuple model, and vice versa. Finally, we establish that the increased power of the defender results in higher-quality protection of the network.

关键词： Protection Power system security computer viruses Power generation economics Polynomials Probability distribution Software systems Safety Contracts computer science

来源：评论

学校读者我要写书评

暂无评论

Making items suggestions in non online environments

引用

WSEAS Transactions on computers 2006年第3期5卷 639-644页

作者： Kouris, Ioannis N. Makris, Christos H. Tsakalidis, Athanasios K. Department of Computer Engineering and Informatics School of Engineering University of Patras 26500 Patras Greece Computer Technology Institute P.O. Box 1192 26110 Patras Greece

Practically all data mining techniques and especially association rules assume an on-line environment in order to operate;such as a web site or an electronic machine. Most businesses though as well as the largest part of current trade are still being made in the traditional off-line way, requiring the physical presence of both the customers and the products, leaving all similar applications unassisted from data mining techniques. In this work we describe a system for delivering items suggestions to customers, tailored for the application that for many initiated data mining research;namely supermarket data.

关键词： Online systems

来源：评论

学校读者我要写书评

暂无评论

The Hungarian space research knowledge management project: A focus on the Rosetta Mission

引用

Journal of Knowledge Management 2006年第2期10卷 76-89页

作者： Sándor Lipusz, Csaba Tróznai, Gábor Bogdány, János Szalai, Sándor Department of Computer Science Faculty of Informatics of ELTE Division of Space Technology of RMKI Budapest Hungary Central Research Institute for Physics Research Institute for Particle and Nuclear Physics KFKI RMKI Budapest Hungary Deutsches Zentrum für Luft-und Raumfahrt Bonn Germany Division of Space Technology KFKI Research Institute for Particle and Nuclear Physics Hungary

Purpose - The Hungarian Academy of Sciences is supported by the Hungarian Ministry of informatics and Communications (RMKI). RMKI started a research and development project in 2003 with the aim of studying the knowledge management methods for long duration space research projects and to develop an information system providing a base for saving and using the knowledge gathered. The aim of this article is to investigate the RMKI research and development project. Design/methodology/approach - This article first describes the environment of the project, details the questions identified by the project staff, and gives some characteristics of the solutions when found. Findings - The article finds that the outcomes identified by a knowledge management project grow fast and have a tendency to become unmanageable very quickly, even if technical questions are taken into consideration when starting. The main question remains whether an acceptable solution exists in the area covered by the economical resources. Originality/value - This article focuses on the technical aspects of knowledge management projects and identifies a mechanism for setting up an information system with the capacity to support knowledge preservation for at least a decade, which is considered to be a long period. © Emerald Group Publishing Limited.

关键词： Hungary Information systems Knowledge management Space technology

来源：评论

学校读者我要写书评

暂无评论

Estimating Hospital Work Activities in Context-Aware Healthcare Applications

Estimating Hospital Work Activities in Context-Aware Healthc...

引用

International Conference on Pervasive Computing Technologies for Healthcare, PervasiveHealth

作者： Jesus Favela Monica Tentori Luis A. Castro Victor M. Gonzalez Elisa B. Moran Ana I. Martinez-Garcia Computer Science Department CICESE Mexico Mexico Computer Science Department CICESE Ensenada Mexico School of Informatics University of Manchester United Kingdom School of Informatics University of Manchester Institute of Science and Technology UK Computer Science Department CICESE Mexico

Hospitals are convenient settings for the deployment of context-aware applications. The Information needs of hospital workers are highly dependent on contextual variables, such as location, role and activity. While some of these parameters can be easily determined, others, such as activity are much more complex to estimate. This paper describes an approach to estimate the activity being performed by hospital workers. The approach is based on information gathered from a work study conducted in a hospital, in which 196 hours of detailed observation of hospital workers was recorded. This data is used to train a back propagation neural network to estimate user activity based on contextual variables such as location, artifacts being used, the presence of colleagues and the subjects' activity. The results indicate that the user activity can be estimated with 75% of accuracy (on average) which could be sufficient for some applications. We discuss how these results can be used in the design of activity-aware hospital information systems

关键词： Hospitals Medical services Neural networks Context Application software Pervasive computing Wireless sensor networks computer science Biomedical informatics Back

来源：评论

学校读者我要写书评

暂无评论

An Embedded Support Vector Machine

An Embedded Support Vector Machine

引用

Workshop on Intelligent Solutions in Embedded Systems

作者： Rasmus Pedersen Martin Schoeberl Department of Informatics CBS Copenhagen Denmark Institute of Computer Engineering University of Technology Vienna Vienna Austria

In this paper we work on the balance between hardware and software implementation of a machine learning algorithm, which belongs to the area of statistical learning theory. We use system-on-chip technology to demonstrate the potential usefulness of moving the critical sections of an algorithm into HW: the so-called hardware/software balance. Our experiments show that the approach can achieve speedups using a complex machine learning algorithm called a support vector machine. The experiments are conducted on a real-time Java virtual machine named Java optimized processor

关键词： Support vector machines Support vector machine classification Machine learning algorithms Kernel Java Hardware Statistical learning Machine learning Embedded system Constraint optimization

来源：评论

学校读者我要写书评

暂无评论

Building knowledge repositories with enterprise modelling and patterns - From theory to practice

Building knowledge repositories with enterprise modelling an...

引用

14th European Conference on Information Systems, ECIS 2006

作者： Stirna, Janis Persson, Anne Aggestam, Lena Department of Computer and Systems Sciences Forum 100 Royal Institute of Technology 164 40 Kista Sweden School of Humanities and Informatics University of Skövde P.O. Box 408 541 28 Skövde Sweden

An approach to building knowledge repositories, Enterprise Knowledge Patterns (EKP), has been developed and applied throughout a number of research projects, most recently in the ELEKTRA, HyperKnowledge1 and EKLär projects. The EKP approach combines Enterprise Modelling with organisational patterns. Systematic evaluations of applying the approach have been carried out in two of the projects, while the third project is currently running. The aim of this paper is to provide an overview of the evaluation results and to share practical experiences from building knowledge repositories with Enterprise Modelling and organisational patterns. We discuss issues concerning the knowledge content of pattern based knowledge repositories, the language used to express knowledge in organisational patterns and technology support for storing and retrieving knowledge components. .

关键词： Knowledge management

来源：评论

学校读者我要写书评

暂无评论

Lowest-ID with adaptive ID reassignment: a novel mobile ad-hoc networks clustering algorithm

Lowest-ID with adaptive ID reassignment: a novel mobile ad-h...

引用

International Symposium on Wireless Pervasive Computing (ISWPC)

作者： D. Gavalas G. Pantziou C. Konstantopoulos B. Mamalis Department of Cultural Technology and Communication University of Aegean Greece Department of Informatics Technological Educational Institute of Athens Greece Computer Technology Institute Patras Greece

Clustering is a promising approach for building hierarchies and simplifying the routing process in mobile ad-hoc network environments. The main objective of clustering is to identify suitable node representatives, i.e. cluster heads (CHs), to store routing and topology information and maximize clusters stability. Traditional clustering algorithms suggest CH election exclusively based on node IDs or location information and involve frequent broadcasting of control packets, even when network topology remains unchanged. More recent works take into account additional metrics (such as energy and mobility) and optimize initial clustering. However, in many situations (e.g. in relatively static topologies) re-clustering procedure is hardly ever invoked; hence initially elected CHs soon reach battery exhaustion. Herein, we introduce an efficient distributed clustering algorithm that uses both mobility and energy metrics to provide stable cluster formations. CHs are initially elected based on the time and cost-efficient lowest-ID method. During clustering maintenance phase though, node IDs are re-assigned according to nodes mobility and energy status, ensuring that nodes with low-mobility and sufficient energy supply are assigned low IDs and, hence, are elected as CHs. Our algorithm also reduces control traffic volume since broadcast period is adjusted according to the nodes mobility pattern: we employ infrequent broadcasting for relative static network topologies, and increase broadcast frequency for highly mobile network configurations. Simulation results verify that energy consumption is uniformly distributed among network nodes and that signaling overhead is significantly decreased.

关键词： Ad hoc networks Clustering algorithms Network topology Broadcasting Intrusion detection Routing Stability Nominations and elections Batteries Communication system traffic control

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：