检索结果-内蒙古大学图书馆

IEEE Conference on Wireless Communications and Networking

作者： Hoang Nam Nguyen S. Olariu P. Todorova Institute of Communication Networks Technical University of of Vienna Vienna Austria Department of Computer Science Old Dominion University Norfolk VA USA FhG Fokus Berlin Germany

ISBN: (纸本)0780373766

Multimedia LEO satellite networks will play an important role in providing truly global coverage required by mobile personal communication services. Due to the high mobility inherent to LEO systems, a number of challenging technical problems arise. The first contribution of this work is to propose a realistic mobility model, taking into account the rotation of the Earth, which was systematically ignored in the literature. Our second contribution is a novel resource reservation strategy, termed sequential probabilistic resource reservation (SPR), specifically designed to minimize connection interruption due to handoffs. Finally, we propose a novel connection admission control (CAC) algorithm, differentiating real-time and non-real-time services. Performance results obtained by simulation show that the novel mobility model is essential for a realistic network performance evaluation and that the novel SPR strategy offers low handoff blocking probability for both service classes and low new call blocking probability for non-real-time connections.

关键词： Low earth orbit satellites Artificial satellites Admission control Personal communication networks Telecommunication traffic Bandwidth Switches Communication networks computer science Mobile computing

来源：评论

学校读者我要写书评

暂无评论

A selective look-ahead bandwidth allocation scheme for reliable handoff in multimedia LEO satellite networks

A selective look-ahead bandwidth allocation scheme for relia...

引用

European Conference on Universal Multiservice networks (ECUMN)

作者： P. Todorova S. Olariu Hoang Nam Nguyen FhG Fokus Berlin Germany Department of Computer Science Old Dominion University Norfolk VA USA Institute of Communication Networks Technical University of of Vienna Vienna Austria

Low Earth orbit (LEO) satellites are expected to support multimedia traffic and to provide their users with the negotiated quality of service (QoS). However, the limited bandwidth of the satellite channel, the rotation of the satellite around the Earth, and the mobility of users makes QoS provisioning and mobility management a challenging task. One important mobility problem is the intra-satellite handoff management. The main contribution of this work is to propose a novel bandwidth allocation scheme along with a connection admission control strategy for LEO satellite networks. Our bandwidth allocation scheme that we call the selective look-ahead strategy (SILK), is specifically tailored to meet the QoS needs of multimedia connections. In SILK, bandwidth allocation for a connection that has stringent call dropping probability (CDP) requirements will differ significantly from that of a more tolerant application. The performance of SILK is compared to that of various bandwidth allocation schemes proposed in the recent literature. Extensive simulation results show that, compared with the other bandwidth allocation schemes, SILK offers low CDP providing for reliable handoff of on-going calls, acceptable call blocking probability (CBP) for new calls, while maintaining resource utilization high.

关键词： Channel allocation Low earth orbit satellites Satellite broadcasting Quality of service Resource management Telecommunication traffic Bandwidth Admission control computer network reliability Telecommunication network reliability

来源：评论

学校读者我要写书评

暂无评论

Variable redundancy coding for mobile channels

Variable redundancy coding for mobile channels

引用

IEEE Symposium on computers and Communications (ISCC)

作者： W. Adi M. Ben-Aoun N. Kassab Institute for Computer and Communication Networks Engineering Technical University of Braunschweig Germany Ajman University of Science and Technology UAE

ISBN: (纸本)0769511775

Mobile data channels carry different communication services with different data formats and rates. In modern CDMA systems as in UMTS, such different data rates and services are carried in a fixed frame. This results with some free data gaps in the frame. A novel coding concept called variable redundancy coding (VRC) to replace the currently used bit repetition for filling such gaps is presented. The key idea behind the proposed VRC is simple: instead of repeating bits to match the channel rate, block code redundancy bits are stuffed in the free gaps. Such VRC bits particularly improve the frame error rate (FER) and at the same time fill the free gaps. This results in a more efficient overall channel throughput, as the data throughput depends mainly on the frame error rate and on the ARQ strategy employed. A particular VRC technique based on the burst error correcting Fire code is presented and is shown to be effective to optimize the overall system performance.

关键词： Redundancy Error analysis Throughput Mobile communication Multiaccess communication 3G mobile communication Filling Block codes Automatic repeat request Error correction codes

来源：评论

学校读者我要写书评

暂无评论

Performance improvements of data-link layer protocol in WATM

Performance improvements of data-link layer protocol in WATM

引用

IEEE International Conference on Communications (ICC)

作者： Sungchun Park Sungwon Lee Young-Jae Song Dong-Ho Cho Yong-Bae Dhong Technical research and Development Korea Data Communications KDC Corporation Anyang South Korea IMT-2000 system developmmt group Samsung Electronics Company Limited South Korea Department of Computer Engineering Kyung Hee University South Korea Department of Electrical Engineering Korea Advanced Institute of Science and Technology South Korea Korea Electronics and Technology Institute South Korea

In these days, a mobile communication service has high-speed and multimedia characteristics. Due to the high error ratio of wireless link environments, a DLC protocol that is optimized for a wire network could not be used in wireless link environments. Thus, the DLC protocol that is suitable for mobile communication environments is required. To solve these problems, we propose an efficient WATM DLC layer protocol. The proposed DLC protocol could support various traffic attributes of high-speed multimedia services. That is, the proposed DLC layer protocol provides a piggyback response, the multiple-ack, and a multiple retransmission mechanism based on SR-ARQ. Also, an outband retransmission scheme using dynamic bandwidth is provided for the delay sensitive service and multi-copy transmission is applied in seriously faded radio environments such as handover. According to the simulation results, the suggested schemes show a better performance than the conventional SR-ARQ protocol in view of the cell transmission delay and throughput.

关键词： Wireless application protocol Delay Forward error correction data communication Throughput Wireless sensor networks Automatic repeat request Mobile communication Error correction Testing

来源：评论

学校读者我要写书评

暂无评论

Applying fuzzy functions and sequential coordination to optimization of machinery arrangement and pipe routing

引用

NAVAL ENGINEERS JOURNAL 1998年第6期110卷 43-54页

作者： Wu, BC Young, GS Schmidt, W Choppella, K Dr. Bi-Chu Wu:received a PhD in Mechanical Engineering from the University of Maryland College Park in 1991. She has worked on projects involving naval architecture design optimization solid mechanics and database development. Presently a senwr engineer with Angle Incorporated Dr Wu's research interests are in design optimization and fuzzy logic applications. Dr. Gin-Shu Young: a senior engineer with Angle Incorporated holds a PhD in Mechanical Engineering from the University of Maryland College Park. As a guest researcher with National Institute of Standards and Technologies from 1990 to 1993 he worked on vision-based navigation for autonomous vehicles. His experience also includes applications of optimization fuzzy logic neural network and genetic algorithm methods to engineering system design Mr. William Schmidt:co-founded Angle Incorporated in 1990 and has served as Vice PresidentlChiefScientist during this tame. He holds a B.Sc. in Applied Science from the Naval Acadt?my and an M.Sc. in Physics from the Naval Post Graduate School. He has cner 20 years experience in technical leadership material and personnel management. He has led the application of computer aided design (CAD) and Product Model Information Exchange to the shipbuilding industry. His experience also includes leading the amlication of model based operational analysis to support the Live Fire Test Program for DDG 51 Class Destroyers. Mr. Krishna M. Choppella:is a Sofware Engineer at Eidea Laboratories Incotporated where he works on componentbased distributed enterpvise frameworks. He has been involved in creating data analysis tools for the US Nay by integrating CAD modeis databases and graphical front ends. His work in the Masters degree program in Mechanical Engineering at the University of Texas at Austin was in di0ddase.r spectroscopy of combustion products in porous-matri burners. He received his Bachelors degree in Electrical Engineering in India. He was a Research Associate at the Centre for Laser Technology and Project Engi

Ship design is often multidisciplinary involving several design elements with various types of objectives and constraints (O/C) some easily described as mathematical formulas, others better modeled as descriptive assertions. This paper describes a method based on fuzzy functions and an integrated performance index to model O/C using descriptive assertions to be used with mathematical formulas in optimization. Another issue addressed in this paper concerns the coordination of design elements when sequentially coupled, that is, when one leads the other and the performance of the follower depends greatly on the design of the leader. Based on neuro-fuzzy techniques, the method described here coordinates and optimizes sequentially coupled elements. The two methods are applied to machinery arrangement (MA) and pipe routing (PR). Preliminary models for optimization of MA and PR are described considering convenience, producibility: engine room size, interference and location as factors in the O/C set. Some test results from MA/PR applications are presented and discussed. The methods are generic and can be extended to other elements in ship design. They are mutually independent and may be used separately Two advantages of their use are an improvement in overall performance and a reduction in the need for redesign of elements.

关键词： Optimization

来源：评论

学校读者我要写书评

暂无评论

Influence of human engineering on manning levels and human performance on ships

引用

NAVAL ENGINEERS JOURNAL 1997年第5期109卷 67-76页

作者： Anderson, DE Oberman, FR Malone, TB Baker, CC David E. Anderson:has a bachelor of science degree in environmental engineering from Florida Technological University and a master's degree in environmental engineering from the University of Central Florida. He is a graduate of the Naval Sea Systems Command's Engineer-In-Training (EIT) Program. Mr. Anderson was instrumental in introducing the collective protection system (CPS) in the U.S. Navy developing the initial forward-fit package for the USS Gunston Hall and the engineering change proposal (ECP) for the USS Wasp. In 1990 he joined the Human Systems Integration (HSI) Division (SEA 55W5) where he was task leader for auxiliary ships. He is currently the HSI manager for the future technology variant of the SeaLift ship and the future carrier. Association of Scientists and Engineers 33rdAnnual Technical Symposium 26 April 1996. Fred R. Oberman:has B.A. and M.A. degrees from the University of Chicago and Loyola University (experimental psychology) and an M.S. degree in industrial engineering and operations research from Virginia Polytechnic Institute (VPI). He has more than 30 years experience in HSI management planning research analysis design and testing in government and private sector positions. He is currently responsible for NavSea HSI generic research and tool development efforts. He is responsible for Human Engineering Specifications and Standards (Commercial Hypertext) and is the NavSea 03D7 representative on HSI in Performance Specifications and for integration of HSI within Integrated Logistic Support (ILS). He has served as DoD HSI SubTAG chair and member of the Simulation and Modeling Test and Evaluation Display and Control Systems Human Computer Interaction Specifications and Standards and Systems Design Sub Tags as a member of the Society of Naval Architects and Marine Engineers (SNAME) Systems Safety Panel and a member of NATO RSG 14 on man-machine analysis. Thomas B. Malone: CHFEP received a Ph.D. in experimental psychology from Fordham University in 1964. He is president of Carlow

The objectives of Human Engineering (HE) are generally viewed as increasing human performance, reducing human error, enhancing personnel and equipment safety, and reducing training and related personnel costs. There are other benefits that are thoroughly consistent with the direction of the Navy of the future, chief among these is reduction of required numbers of personnel to operate and maintain Navy ships. The Naval Research Advisory Committee (NRAC) report on Man-Machine Technology in the Navy estimated that one of the benefits from increased application of man-machine technology to Navy ship design is personnel reduction as well as improving system availability, effectiveness, and safety The objective of this paper is to discuss aspects of the human engineering design of ships and systems that affect manning requirements, and impact human-performance and safety The paper will also discuss how the application of human engineering leads to improved performance, and crew safety, and reduced workload, all of which influence manning levels. Finally, the paper presents a discussion of tools and case studies of good human engineering design practices which reduce manning.

关键词： Human engineering

来源：评论

学校读者我要写书评

暂无评论

OPTIMUM FREQUENCY REUSE IN MOBILE TELEPHONY SYSTEMS

引用

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第3期8卷 185-190页

作者： KAZANTZAKIS, MG DEMESTICHAS, PP ANAGNOSTOU, ME National Technical University of Athens Computer Science Division Department of Electrical and Computer Engineering Heroon Polytechneiou 9 Zografou Athens 15773 Greece Michael G. Kazantzakii was born in Athens Greece in 1962. He received both the Diploma and Ph.D. Degree from the Electrical Engineering Department of the National Technical University of Athens in 1986 and 1992 respectively. During the period 1992–1993 he was a member of the Staff of the Hellenic Navy Research Centre working in the area of underwater acoustics. Since 1994 he has been a researcher at the National Technical University of Athens Department of Electrical Engineering and Computer Science Telecommunications Laboratory. His interests include data mobile and integrated services networks. Panagiotis P. Demestichas was born in Athens Greece in 1967. He received the Diploma in electrical engineering from the National Technical University of Athens (NTUA) Athens in 1993. At present he is a research assistant at NTUA working towards his Ph.D. dissertation. He participated in the BRITE/EURAM-EURATN and in the RACE-TOMQAT and MONET projects. His research interests are in the areas of broadband and mobile networks queueing theory algorithms and complexity theory. He is a Member of the Technical Chamber of Greece. Miltiades E. Anagnostou was born in Athens in 1958. He received the Electrical Engineers Diploma from the National Technical University of Athens (NTUA) in 1981. During the period 1981–1987 he was a teaching assistant at NTUA. In 1987 he received his Ph.D. in the area of computer networks. In 1987–1989 he served the Greek army in the Air Force Research and Development Center. In 1989–1991 he was a Lecturer and since 1991 he has been an Assistant Professor in the Computer Science Division Department of Electrical and Computer Engineering of the NTUA. He teaches courses on modern telecommunications formal specification of protocols stochastic processes and queueing theory. Since 1981 Dr. Anagnostou has been involved

The reason why cellular mobile telephony systems exist is that they allow frequency reuse. Dynamic allocation algorithms improve the network efficiency and the service quality. Dynamic allocation is closely related to the following instantaneous allocation problem: given a number of channels (frequencies), a cell structure and the number of calls to be accommodated in each cell, find the optimum allocation of channels to cells subject to restrictions concerning the distance of cells, where the same frequency can be reused. In this paper we formulate and solve this problem by showing that it can be reduced to a 0-1 programming problem. Finally we present results, and draw subsequent conclusions.

关键词： MOBILE TELEPHONY FREQUENCY ALLOCATION UMTS

来源：评论

学校读者我要写书评

暂无评论

A DISTRIBUTED MEDIA ACCESS PROTOCOL FOR PACKET RADIO networks AND PERFORMANCE ANALYSIS .2. NETWORK SET-UP TIME AND data RATE

引用

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第1期8卷 49-63页

作者： POND, LC LI, VOK Communication Sciences Electrical Engineering Systems University of Southern California Los Angeles CA 90089-2565 U.S.A. Lawrence C. Pond received the M.Sc. and Ph.D. degrees in electrical engineering from the University of Southern California in 1983 and 1990 respectively. Dr. Pond is currently a scientist at Hughes Space and Communications Company having joined in 1980. He has worked in the fields of communication system design mobile communication network and spacecraft payload design. He is currently working on the development of satellite-based ATM transport and switching architectures for BISDN and Defense Information System Network amlications. Dr. Pond is a member of IEEE. Victor O. K. Li was born in Hong Kong in 1954. He received his SB SM and Sc.D. degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology Cambridge Massachusetts in 1977 1979 and 1981 respectively. Since February 1981 he has been with the University of Southern California (USC) LOS Angeles California where he is Professor of Electrical Engineering and Director of the USC Communication Sciences Institute. He has published 150 technical papers and has lectured and consulted extensively around the world. His research interests include high-speed communication networks personal communication networks intelligent networks distributed databases queueing theory graph theory and applied probability. Dr. Li is very active in the Institute of Electrical and Electronic Engineers (IEEE) having been a member of the Computer Communications Technical Committee since 1983 and having served as Chairman from 1987–1989. He served as Chairman of the Los Angeles Chapter of the IEEE Information Theory Group from 1983–1985. He is the Steering Committee Chair of the International Conference on Computer Communications and Networks (IC3 N) General Chair of the 1st Annual IC3N held in San Diego California in June 1992 General Chair and Technical Program Chair of the 4th IEEE Workshop on Comp

In this, the second part of a two-part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set-up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade-off between the data rate and set-up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set-up time trade-off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes.

关键词： PACKET RADIO NETWORK EPLRS DISTRIBUTED NETWORK TDMA VIRTUAL CIRCUITS MULTIHOP NETWORK BOUNDED DELAY MOBILITY NETWORK SET-UP TIME HIERARCHICAL NETWORK NETWORK data RATE

来源：评论

学校读者我要写书评

暂无评论

Development and application of MCAL tools for marine radar instruction

引用

computer Applications in Engineering Education 1995年第4期3卷 259-259页

作者： Guirguis, S. Korany, E. Abdel-Bary, A. Institute of Graduate Studies and Research Alexandria University Alexandria Egypt Shawkat K. Guirguis:obtained the BSc and M.Sc. degrees in Computer Science and Automatic Control Faculty of Engineering Alexandria University in 1981 and 1984 respectively. In 1988 he obtained a PhD degree in Electronics and Communications Faculty of Engineering Cairo University co-supervised by the Imperial College of Science and Technology University of London where he spent two years as an academic visitor. His current research interests include software quality management multimedia automatic programming and decision support systems. He is currently a lecturer of Computer Science at the Institute of Graduate Studies & Research Alexandria University. Ezzat A. Korany:received the BS degree in Electrical Engineering (Electronics Section) from the University of Alexandria Egypt in 1971 the MS degree in Electrical Engineering (Computer Section) from Ain Shams University Cairo Egypt in 1977 and the PhD degree in Electrical Engineering (Digital Systems) from Florida Institute of Technology U.S.A. in 1982. He is currently an associate professor of Computer Science at the Institute of Graduate Studies & Research University of Alexandria. His research interests are in data communications and multimedia applications computer networks image processing and pattern recognition. Abdel-Latif A. Abdel-Bary:obtained the BEng degree in Electronics Technology from Arab Maritime Transport Academy in 1986. In 1995 he obtained the MSc degree in Information Technology from the Institute of Graduate Studies & Research Alexandria University. His current research interests include ICAL hypermedia and automatic programming.

In this article a multimedia computer-assisted learning (MCAL) system is presented. The major objective of this work was to investigate the potential of using such systems as tools for transferring instructional course information through various types of computer media as opposed to the classic CAL systems. The philosophy and techniques employed to design the system are investigated. Usage of the implemented system and its merits have been illustrated through its application to teach engineering students and technicians the theory and concepts of marine radar. System design, implementation, test, and revision phases are presented and discussed.

关键词：

来源：评论

学校读者我要写书评

暂无评论

ISDN LOOP EXTENSION USING A MID-SPAN AMPLIFIER

引用

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第3期8卷 219-224页

作者： ERKER, GJ DODDS, DE KRZYMIEN, WA David E. Dodds was born in Saskatoon Canada in 1945. He received the B. Eng. and MSc. degrees from the University of Saskatchewan in 1966 and 1968 respectively. He worked with Bell Northern Research (Ottawa) on PBX design in 1969 1972 and 1978. Since 1969 he has been with the University of Saskatchewan where he is currently Professor of Electrical Engineering. He teaches courses in electronics and communications and also presents short courses on the fundamentals of telephony. Current research interests are in data transmission signal processing architecture and frame synchronization for PCM and spread spectrum systems. He has been granted five patents relating to commercial products in delta-modulation telephone line interfacing and computer data transmission. In 1986 he was on sabbatical leave at BNR Inc. and worked with an ANSI committee on the standardization of FDDI-II a combined voice and data system. Mr. Dodds is a Registered Consulting Engineer in Saskatchewan. Witold A. Krzyden received his MSc. (Eng.) and Ph.D. degrees (both in Electrical Engineering) in 1970 and 1978 respectively from the Poznan Technical University in Poznan Poland. He was awarded the Minister's of Science and Technology Prize of Excellence for his Ph.D. thesis. From 1970 to 1978 he was a Research Engineer and Teaching Assistant and then from 1978 to 1980 an Assistant Professor of Electrical Engineering at the Poznan Technical University. In 1980 he won a Dutch Government Research Fellowship at the Twente University of Technology in Enschede the Netherlands for the year of 1980/1981. In the following year of 1981/82 he was a Research Assistant Professor there. From 1982 to 1986 he was an Assistant Professor of Electrical Engineering at Lakehead University in Thunder Bay Ontario Canada. In 1986 he joined the Univeristy of Alberta and Alberta Telecommunications Research Centre (now Telecommunications Research Laboratories or TRLabs) as an Associate Professor of Electrical Engineering. Currently he is a Professor of E

The 5.5 km range of the basic rate ISDN loop has been extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by 1.0 km, whereas the 2w/4w amplifier extends the range by 1.5 km at the expense of increased complexity. As part of the amplifer design, a resistor/capacitor network has been developed which closely matches the characteristic impedance of telephone cable. Error rate tests have been conducted using various lengths of cable and an operating ISDN line.

关键词： ISDN PHYSICAL LAYER BASIC RATE LOOP RANGE EXTENSION

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：