Application of Asynchronous Transfer Mode (Atm) technology to Picture Archiving and Communication Systems (Pacs): A survey

Broadband Integrated Services Digital Network (R-ISDN) provides a range of narrowband and broad-band services for voice, video, and multimedia. Asynchronous Transfer Mode (ATM) has been selected by the standards bodies as the transfer mode for implementing B-ISDN; The ability to digitize images has lead to the prospect of reducing the physical space requirements, material costs, and manual labor of traditional film handling tasks in hospitals. The system which handles the acquisition, storage, and transmission of medical images is called a Picture Archiving and Communication System (PACS). The transmission system will directly impact the speed of image transfer. Today the most common transmission means used by acquisition and display station products is Ethernet. However, when considering network media, it is important to consider what the long term needs will be. Although ATM is a new standard, it is showing signs of becoming the next logical step to meet the needs of high speed networks; This thesis is a survey on ATM, and PACS. All the concepts involved in developing a PACS are presented in an orderly manner. It presents the recent developments in ATM, its applicability to PACS and the issues to be resolved for realising an ATM-based complete PACS. This work will be useful in providing the latest information, for any future research on ATM-based networks, and PACS

Renegotiable VBR service

In this work we address the problem of supporting the QoS requirements for applications while efficiently allocating the network resources. We analyse this problem at the source node where the traffic profile is negotiated with the network and the traffic is shaped according to the contract. We advocate VBR renegotiation as an efficient mechanism to accommodate traffic fluctuations over the burst time-scale. This is in line with the Integrated Service of the IETF with the Resource reSerVation Protocol (RSVP), where the negotiated contract may be modified periodically. In this thesis, we analyse the fundamental elements needed for solving the VBR renegotiation. A source periodically estimates the needs based on: (1) its future traffic, (2) cost objective, (3) information from the past. The issues of this estimation are twofold: future traffic prediction given a prediction, the optimal change. In the case of a CBR specification the optimisation problem is trivial. But with a VBR specification this problem is complex because of the multidimensionality of the VBR traffic descriptor and the non zero condition of the system at the times where the parameter set is changed. We, therefore, focus on the problem of finding the optimal change for sources with pre-recorded or classified traffic. The prediction of the future traffic is out of the scope of this thesis. Traditional existing models are not suitable for modelling this dynamic situation because they do not take into account the non-zero conditions at the transient moments. To address the shortfalls of the traditional approaches, a new class of shapers, the time varying leaky bucket shaper class, has been introduced and characterised by network calculus. To our knowledge, this is the first model that takes into account non-zero conditions at the transient time. This innovative result forms the basis of Renegotiable VBR Service (RVBR). The application of our RVBR mathematical model to the initial problem of supporting the applications' QoS requirements while efficiently allocating the network resources results in simple, efficient algorithms. Through simulation, we first compare RVBR service versus VBR service and versus renegotiable CBR service. We show that RVBR service provides significant advantages in terms of resource costs and resource utilisation. Then, we illustrate that when the service assumes zero conditions at the transient time, the source could potentially experience losses in the case of policing because of the mismatch between the assumed bucket and buffer level and the policed bucket and buffer level. As an example of RVBR service usage, we describe the simulation of RVBR service in a scenario where a sender transmits a MPEG2 video over a network using RSVP reservation protocol with Controlled-Load service. We also describe the implementation design of a Video on Demand application, which is the first example of an RVBR-enabled application. The simulation and experimentation results lead us to believe that RVBR service provides an adequate service (in terms of QoS guaranteed and of efficient resource allocation) to sources with pre-recorded or classified traffic

Sixth Goddard Conference on Mass Storage Systems and Technologies Held in Cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems

This document contains copies of those technical papers received in time for publication prior to the Sixth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems at the University of Maryland-University College Inn and Conference Center March 23-26, 1998. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the management of large volumes of data. The Conference encourages all interested organizations to discuss long term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long term retention of data, and data distribution. This year's discussion topics include architecture, tape optimization, new technology, performance, standards, site reports, vendor solutions. Tutorials will be available on shared file systems, file system backups, data mining, and the dynamics of obsolescence

Desenvolvimento de um driver para comunicação síncrona sobre IEEE1394

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação

The Need For Hands-On IT Classes

This paper describes why SIU needs a class that incorporates hands on in an advance telecommunications course. It gives a brief history of the Internet along with the need for IT skilled workers their education and the future expectations of the Internet. The paper also gives an example of what the class structure would be. This class has some differences between the two networking courses already in existences regards to their outcomes. ELM 415 would be very Hands-on type of course where students spend a great deal of time in lab installing and configuring software and hardware. The assessment would be primarily performance based, where they have to demonstrate working systems. The course would be a last in a series of courses that have been designed so that students who wish to put in a little more time on their own can be prepared to take the Cisco Certified Network Associate certification test. The prerequisite courses to ELM 415 are similar in that they are very lab intensive with a focus on installation, configuration, and troubleshooting. With a large growth and need in the IT field, SIU needs to take advantage of this and advance students in their personal growth and education. SIU also can take advantage of the opportunity of economic growth, of which comes student enrollment and recognition in the field

Large-Scale Client/Server Migration Methodology

The purpose of this dissertation is to explain how to migrate a medium-sized or large company to client/server computing. It draws heavily on the recent IBM Boca Raton migration experience. The client/server computing model is introduced and related, by a Business Reengineering Model, to the major trends that are affecting most businesses today, including business process reengineering, empowered teams, and quality management. A recommended information technology strategy is presented. A business case development approach, necessary to justify the large expenditures required for a client/server migration, is discussed. A five-phase migration management methodology is presented to explain how a business can be transformed from mid-range or mainframe-centric computing to client/server computing. Requirements definition, selection methodology, and development alternatives for client/server applications are presented. Applications are broadly categorized for use by individuals (personal applications) or teams. Client systems, server systems, and network infrastructures are described along with discussions of requirements definition, selection, installation, and support. The issues of user communication, education, and support with respect to a large client/server infrastructure are explored. Measurements for evaluation of a client/server computing environment are discussed with actual results achieved at the IBM Boca Raton site during the 1994 migration. The dissertation concludes with critical success factors for client/server computing investments and perspectives regarding future technology in each major area

Technology 2004, Vol. 2

Proceedings from symposia of the Technology 2004 Conference, November 8-10, 1994, Washington, DC. Volume 2 features papers on computers and software, virtual reality simulation, environmental technology, video and imaging, medical technology and life sciences, robotics and artificial intelligence, and electronics