Pubs:2000

<bibtex> @inproceedings{265, author={Upchurch,E. ; Murphy, J.}, title={Why Worry about Performance in e-commerce Solutions}, booktitle={IEE 16th UK Teletraffic Symposium}, year={2000}, abstract={This paper will discuss the evolution of computer systems, and will show that while the system performance is getting increasingly critical, it is also getting harder to master performance assurance and to master the system evolution. This paper proposes that the real challenge posed currently for the performance engineer is the explosion of e-Commerce systems where the users are increasingly impatient and the design methodologies are in their infancy. The reason that the systems are getting more complex is that the system dynamics are critical to performance, but they are not addressed by traditional design methodologies. One solution to this is to use a performance assurance process that guarantees that the system dynamics are captured. Overall the odds are not good for building complex systems, but performance assurance can reduce risk by a factor of ten or more.}, keywords={E-Commerce}, pdf={why worry.pdf}, } </bibtex> <bibtex> @inproceedings{266, author={Murphy, J.}, title={Assuring Performance in E-Commerce Section}, booktitle={IEE 16th UK Teletraffic Symposium}, year={2000}, abstract={Performance Assurance is a methodology that, when applied during the design and development cycle, will greatly increase the chances of an e-Commerce project satisfying user performance requirements first time round. This paper discusses the primary risk factors in development projects, the keys to a successful risk management programme, and the tools required. It also discusses problems that can occur in e-Commerce systems and some examples of how these might manifest themselves. A definition and the reasoning behind a performance assurance methodology is given, and the performance assurance methodology that is proposed is outlined.}, keywords={E-Commerce}, pdf={Assuring.pdf}, } </bibtex> <bibtex> @proceedings{344, editor={G.Muntean;L.Murphy}, title={Some Software Issues of a Real-Time Multimedia Networking System}, year={2000}, address={Timisoara,Romania}, abstract={The transmission of related multimedia data causes problems because of their very large size and continuous nature. Unlike the majority of the existing solutions for transmitting continuous media, which use connectionless protocols, we propose one that uses a connection-oriented protocol (TCP/IP). An object-oriented approach is used to build both server and client, allowing easier system debugging and expansion. We implemented a buffering mechanism which allows us to continue playing for a period when the network load increases. Multithreading is used to solve some problems which require concurrent solutions.}, keywords={TCP/IP,Multimedia}, pdf={software.pdf}, } </bibtex> <bibtex> @proceedings{345, editor={C.Hava;S.Holban;J.Murphy;L.Murphy}, title={Initial Tool for Monitoring Performance of Web Sites}, year={2000}, abstract={A very important application, which offers access to information on the Internet, is the World Wide Web (WWW or Web). The WWW is primarily responsible for the growth of e-commerce activity by the use of the Internet. To improve users' satisfaction with e-commerce WWW services, a lot of work has been done on characterizing the performance of Internet applications and servers. We discuss in this article about a monitoring application for performance measurement of the WWW Servers. By observing the behaviour of WWW servers and measuring their performance, we can estimate several performance indices. Our application simulates the access of a number of clients to the same Web page and its links and analyses the results. Three different cases are taken into account: the clients access the same Web page one after the other (i.e. serially), at the same time (i.e. in parallel), checking before a ‘cache’ structure.}, keywords={Web,Internet}, pdf={initial tool.pdf}, } </bibtex> <bibtex> @proceedings{346, editor={G.Muntean;L.Murphy}, title={An Object-Oriented Prototype System for Feedback Controlled Multimedia Networking}, year={2000}, address={Dublin,Ireland}, abstract={Multimedia networking refers to the transfer of related audio, video, images, text and/or data among networked computers. Because of their very large filesize and their continuous nature, these transfers are problematic. Unlike the majority of proposed solutions for transmitting continuous media, which either request a dedicated connection or use connectionless protocols, we propose a solution which uses a connection-oriented protocol (TCP/IP). A dynamic feedback and buffering mechanism allows us to continue with the transmission even in the case that the network load increases, decreasing the necessary bandwidth by gradually reducing the quality of the transmitted stream. Transmission quality is restored when the network traffic reduces. An object-oriented approach is used to build both server and client, allowing easier system debugging and expansion. Multithreading is used to solve some problems which require concurrent solutions.}, keywords={dynamic feedback scheme, audio/video synchronization, multimedia networking}, pdf={object oriented.pdf}, } </bibtex> <bibtex> @proceedings{347, editor={N.Cranley;L.Fiard;L.Murphy}, title={Quality of Service for Streamed Multimedia over the Internet}, year={2000}, address={Dublin,Ireland}, abstract={Multimedia is any combination of text, graphics, audio, video, animation and data. Multimedia applications over the Internet include Video on Demand (VoD), interactive video, and videoconferencing. However there are limitations to these applications, as it is often required that a multimedia file be completely downloaded before it can be played or viewed. Streaming is the ability to start processing data before all of it has arrived, thus making delivery in real-time or near real-time possible. Streaming technologies are designed to overcome the problem of limited bandwidth. The implication of this is that multimedia files of any size can be played/displayed over the Internet in real-time or near real-time. To date, there has been no definitive way to transmit streamed MPEG-4 files across the Internet with an associated Quality of Service. One possibility is to write a control protocol on top of TCP/IP, which manages the flow of multimedia data [1]. In this paper, an alternative approach using a protocol stack comprising a Real-time Transport Protocol (RTP) layer over a User Datagram Protocol (UDP)/Internet Protocol (IP) layer is described. Firstly we provide a brief description of MPEG/MPEG-4 and RTP/RTCP, followed by a description of the system implemented and plans for its future development.}, keywords={Multimedia,Real-time}, pdf={quality of service.pdf}, } </bibtex> <bibtex> @proceedings{348, editor={C.Hava;L.Murphy}, title={Performance Measurement of World Wide Web Servers}, year={2000}, address={Harlow,England}, abstract={The World Wide Web (WWW, or Web) is one of the most important Internet services, and has been largely responsible for the increasing popularity of the Internet in recent years. The WWW continues to expand in both size and content, and is primarily responsible for the growth of e-commerce activity by the use of the Internet. To improve users' satisfaction with e-commerce WWW services, a lot of work has been done on characterizing the performance of Internet applications and servers. In this paper we outline a monitoring application for performance measurement of WWW servers. By observing the behaviour of WWW servers and measuring their performance, we can estimate several performance indices. Our monitoring application simulates the access of a number of clients to the same Web page and its links. Our simulator allows the user to choose different scenarios based on different ways clients can access a Web page, and compare the resulting times.}, keywords={WWW Servers,Internet}, pdf={performance measurement.pdf}, } </bibtex>