检索结果-内蒙古大学图书馆

Real-Time Technology and Applications Symposium

作者： S.-W. Moon K.G. Shin J. Rexford Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA Network Mathematics Research Networking and Distributed Systems AT and T Research Laboratories Murray Hill NJ USA

In packet-switched networks, queueing of packets at the switches can result when multiple connections share the same physical link. To accommodate a large number of connections, a switch can employ link-scheduling algorithms to prioritize the transmission of the queued packets. Due to the high-speed links and small packet sizes, a hardware solution is needed for the priority queue in order to make the link schedulers effective. But for good performance, the switch should also support a large number of priority levels (P) and be able to buffer a large number of packets (N). So a hardware priority queue design must be both fast and scalable (with respect to N and P) in order to be implemented effectively. In this paper we first compare four existing hardware priority queue architectures, and identify scalability limitations on implementing these existing architectures for large N and P. Based on our findings, we propose two new priority queue architectures, and evaluate them using simulation results from Verilog HDL and Epoch implementations.

关键词： Packet switching Switches Traffic control Scheduling algorithm Asynchronous transfer mode Hardware design languages Communication system traffic control computer architecture Moon Real time systems

来源：评论

学校读者我要写书评

暂无评论

Issues of security and network security in health care information systems

Issues of security and network security in health care infor...

引用

作者： Patel, Ahmed Kantzavelou, Ioanna Computer Networks and Distributed Systems Research Group Department of Computer Science University College Dublin Belfield Dublin 4 Ireland

A Health Care Establishment (HCE) is an establishment where medical services are rendered. The above services are provided by the health care personnel. The infrastructure of a HCE may include Information Technology (IT) equipment that stores and processes HC information. Previously, IT equipment consisted solely of stand-alone systems, whereas in recent years, the trend has been towards computer networks and distributed systems in HCEs. The spread of distributed information technology in HCEs have necessitated the implementation of Security in HCISs, to assure confidentiality, integrity and availability of HCE information. This paper discusses the issues of Security and Network Security in Health Care Information systems (HCISs). It also suggests a method in establishing Network Security Guidelines and describes Principles for the provision of Network Security in HCEs. © 1996, The SEISMED Consortium.

关键词： Network security

来源：评论

学校读者我要写书评

暂无评论

An overview of the tigger object-support operating system framework 23rd

An overview of the tigger object-support operating system fr...

引用

23rd Seminar on Current Trends in Theory and Practice of Informatics, SOFSEM 1996

作者： Cahill, Vinny Distributed Systems Group Department of Computer Science Trinity College Dublin Ireland

ISBN: (纸本)3540619941

This paper describes the motivations for and main features of Tigger - a framework for the construction of a family of object-support operating systems that can be tailored for use in a variety of different application domains. An important goal of the design of Tigger is that instantiations of the framework should be able to support (a number of) different object models in order to allow a range of object-oriented languages for distributed or persistent programming to be supported without unnecessary duplication of effort. A further goal of the design is that instantiations of the framework should be able to support the same object model in different ways depending on the requirements of the applications to be supported by those instantiations. This paper describes the main features of the Tigger framework that allow these goals to be realised. © 1996, Springer-Verlag. All rights reserved.

关键词： Object oriented programming

来源：评论

学校读者我要写书评

暂无评论

Programming replicated systems in Ada 95

引用

computer JOURNAL 1996年第5期39卷 361-373页

作者： Wellings, AJ Burns, A Real-Time Systems Research Group Department of Computer Science University of York York YO1 5DD UK

This paper considers the programming of passive (cold and warm standbys) and active replicated systems in Ada 95. We show that it is relatively easy to develop systems which act as standbys using the facilities provided by the language and the distributed systems Annex. Arguably, active replication in Ada 95 can be supported in a manner which is transparent to the application. However, this is implementation-dependent, requires a complex distributed consensus algorithm (or a carefully chosen subset of the language to be used) and has little flexibility. We therefore consider two extensions to the distributed systems Annex to help give the application programmer more control. The first is a via a new categorization pragma which specifies that a RCI package can be replicated in more than one partition. The second is through the introduction of a coordinated type which has a single primitive operation. Objects which are created from extensions to coordinated types can be freely replicated across the distributed system. When the primitive operation is called, the call is posted to all sites where a replica resides, effectively providing a broadcast (multicast) facility. We also consider extensions to the partition communication subsystem which implement these new features.

关键词： computer systems programming

来源：评论

学校读者我要写书评

暂无评论

Transaction specification for object-oriented realtime systems in HRT-HOOD 2nd

Transaction specification for object-oriented realtime syste...

引用

2nd International Eurospace-Ada-Europe Symposium, Ada in Europe 1995

作者： Cornwell, Pete Wellings, Andy Distributed Objects Research Group Department of Computing Bournemouth University Dorset United Kingdom Real-Time Systems Research Group Department of Computer Science University of York York United Kingdom

ISBN: (纸本)3540607579

Object-oriented development is a structuring paradigm. It does not provide substantial support for the specification of ‘end to end’ control and data flow. This has implications for hard real-time system development, where applications may specify ‘end to end’ response times, also known as transactions. This paper introduces a graphical notation for the specification of transactions in HRT-HOOD, an object-oriented design technique for hard real-time system development. It provides an overview of the notation, and its practical application as part of a ‘top-down’ development process. This is illustrated through a case study, based on a naval command-control system. © Springer-Verlag Berlin Heidelberg 1996.

关键词： Specifications

来源：评论

学校读者我要写书评

暂无评论

Transaction integration for reusable hard real-time components

Transaction integration for reusable hard real-time componen...

引用

IEEE International Symposim on High Assurance systems Engineering

作者： P. Cornwell A. Wellings Distributed Objects Research Group Department of Computing Bournemouth University UK Real-Time Systems Research Group Department of Computer Science University of York UK

The paper presents a strategy for the composition of components to meet 'end to end' timing requirements. This is a framework based approach known as transaction integration. A framework is constructed through the use of transactions. A transaction represents a control and data flow path across a set of component interfaces, or placeholders, that must be completed by a specific deadline. Reusable real time components are 'plugged' into each placeholder. The paper provides techniques to verify that the performance characteristics of each placeholder, and the 'end to end' deadlines associated with each transaction are met.

关键词： Real time systems Object oriented modeling Plugs Sockets distributed computing computer science Timing Weapons Bibliographies Artificial intelligence

来源：评论

学校读者我要写书评

暂无评论

An overview of catalog design problems in resource discovery

引用

INTERNET research-ELECTRONIC NETWORKING APPLICATIONS AND POLICY 1996年第1期6卷 33-&页

作者： Goodchild, A Andrew Goodchild is a PhD student at the Department of Computer Science University of Queensland QLD 4072 Australia. Tel: +61 7 3365 4209 Fax: +61 7 3365 1999 E‐mail: andrewg@cs.uq.oz.au . He is also affiliated as a Student with the Distributed Systems Technology Centre DSTC and the Research Data Network Collaborative Research Centre RDN‐CRC

Discusses some of the problems designers face in building catalogs in large networks and relates them back to the resource discovery problem. Currently many catalogs tend to be built in an ad hoc fashion-which leads to a great variety in the quality of publicly accessible network catalogs. Furthermore, the research surrounding these catalogs tends to focus on narrow technical issues-resulting in difficult-to-use catalogs. Addresses this problem by providing a usability framework based on the library science and human computer interaction literature, and demonstrates some of those principles via an example of a prototype. Results are interesting to resource discovery tool developers in that a framework for understanding the general resource discovery problem is provided and some techniques for dealing with those problems are presented.

关键词： design and development information retrieval interfaces resources

来源：评论

学校读者我要写书评

暂无评论

An efficient and practical local synchronous bandwidth allocation scheme for the timed-token MAC protocol

An efficient and practical local synchronous bandwidth alloc...

引用

IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： Sijing Zhang A. Burns A. Wellings Department of Computer Science Real Time Systems Research Group University of York UK

This paper is concerned with deadline guarantees of synchronous messages with deadlines equal to periods, in a timed token ring network such as FDDI where the timed token medium access control (MAC) protocol is used. The timed token protocol guarantees a bounded access time and an average bandwidth for synchronous traffic. However, this guarantee alone, though necessary, is insufficient for guaranteeing the transmission of synchronous messages before their deadlines. To ensure timely delivery, the synchronous bandwidth must be carefully allocated to individual nodes. We propose and analyse an efficient and practical local synchronous bandwidth allocation (SBA) scheme. The new scheme performs better than any previously published as it calculates the synchronous bandwidth such that during the message period, the total synchronous transmission time definitely available (when judged only by local information) is exactly equal to the transmission time required. Our scheme also differs significantly from previously reported ones by explicitly taking into account the synchronous bandwidth allocation for message sets whose minimum message deadlines (D/sub min/) are less than twice the target token rotation time (TTRT), and consequently can apply to any synchronous message set (with D/sub min/>TTRT). The feasibility of the allocations produced by the proposed scheme and the worst case achievable utilisation of the scheme are also discussed.

关键词： Channel allocation Access protocols Bandwidth Media Access Protocol Real time systems FDDI Time factors computer science Token networks Optical fiber networks

来源：评论

学校读者我要写书评

暂无评论

Design choices for symmetric key based inter-domain authentication protocols in distributed systems

Design choices for symmetric key based inter-domain authenti...

引用

Annual computer Security Applications Conference

作者： M. Hitchens V. Varadharajan Basser Department of Computer Science University of Sydney Australia Distributed Systems and Network Security Research Uniti Department of Computing University of Western Sydney Australia

Authentication is a key requirement in the establishment of secure interactions between network entities. Several authentication and key establishment protocols have been proposed in recent years. Most of these protocols were designed for an intra-domain environment (i.e. one where the communicating parties reside in a single domain) and then extrapolated to the inter-domain environment. In this paper, the design of inter-domain protocols is investigated. We present the different design choices that need to be carefully considered when designing inter-domain protocols in large distributed systems. We propose three different inter-domain protocols with varying degrees of responsibility placed on the client and the trusted servers. In each case, the assumptions made in the design are explicitly stated. This helps to illustrate the rationale behind the choices made. The proposed protocols use symmetric key systems and are based on Kerberos. The arguments, rationales and designs presented in this paper are also applicable to OSF's distributed Computing Environment (DCE).

关键词： Authentication Protocols Network servers distributed computing Intelligent networks computer networks Certification Wide area networks Security Bridges

来源：评论

学校读者我要写书评

暂无评论

Identification of the lung boundaries in MR images using neural networks

Identification of the lung boundaries in MR images using neu...

引用

Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： I. Middleton R.I. Damper Image Speech and Intelligent Systems Research Group Department of Electronics and Computer Science University of Southampton Southampton UK

Segmentation of medical images is an important first step in their interpretation. Thus an automatic segmentation technique would be of great benefit by reducing the manual effort currently required for this task. This paper reports on the use of neural networks in identifying the lung boundary in magnetic resonance images of the thorax. The networks are able to segment the slices used in training. Improved performance on unseen slices can be achieved using weight elimination and multi-slice training data.

关键词： Lungs Neural networks Image segmentation Biomedical imaging Manuals Thorax Training data Magnetic resonance Intelligent networks Speech

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：