Showing papers on "Network topology published in 1978"
03 Apr 1978
TL;DR: An augmented data manipulator network using a modified control structure to perform more single pass interconnections than the other networks is presented.
Abstract: Four SIMD multistage networks - Feng's data manipulator, STARAN flip network, omega network, and indirect binary n-cube—are analyzed. Three parameters - topology, interchange box, and control structure—are defined. It is shown that the latter three networks use equivalent topologies and differences in their capabilities result from the other parameters. An augmented data manipulator network using a modified control structure to perform more single pass interconnections than the other networks is presented. Some problems may be solved more efficiently if the 2n processing elements of an SIMD machine can be partitioned into submachines of size 2r. Single and multiple control partitioning are defined. The capabilities of these multistage networks to perform in these partioned environments are discussed.
132 citations
04 Dec 1978
TL;DR: In this article, a communication network for a tree-structured assembly (X-TREE) of single-chip processors is described, and considerations for selecting this particular approach are discussed.
Abstract: A communication network for a tree-structured assembly (X-TREE) of single-chip processors is described, and considerations for selecting this particular approach are discussed. The communication links between the processors are high-speed, byte-parallel connections with an asynchronous handshaking protocol. Each node of X-TREE consists of a powerful processor, a switching network and a dedicated communications controller. The latter checks the availability of the links terminating in this node, supervises the creation and elimination of message channels and controls the routing and time multiplexing of concurrent messages over the same link. The switching network inside each X-NODE connects the external links with the internal processor via a fast multiplexed bus which is interfaced to each input/output port through fifo message buffers. Network topology, routing algorithm, addressing scheme, message format and communication hardware are discussed.
38 citations
TL;DR: Although the prime emphasis is on circuit switching networks, other networks involving message switches, packet switches, and integrated voice/data nodal configurations are also considered.
Abstract: This paper examines the network timing and synchronization requirements for various network topologies. Both centralized and decentralized topologies are considered. Although the prime emphasis is on circuit switching networks, other networks involving message switches, packet switches, and integrated voice/data nodal configurations are also considered.
17 citations
TL;DR: By proper selection of the topology of the equivalent network, sparsity effects are retained while the accuracy of outage analysis using the equivalent model is maintained within predetermined bounds.
Abstract: A methodology is developed for obtaining network equivalents of external systems for on-line security assessement purposes. The problem is formulated either as a constrained or unconstrained optimization problem. By proper selection of the topology of the equivalent network, sparsity effects are retained while the accuracy of outage analysis using the equivalent model is maintained within predetermined bounds. This methodology is foreseen as the basis for testing and updating network equivalents for on-line applications.
16 citations
TL;DR: A sufficient condition for unimodularity is developed that is based upon the topological characteristics of the associated graph, and the results are applied to certain well-structured examples.
Abstract: In this paper we investigate the nature of integer solutions to multicommodity network flow problems from a graphtheoretic viewpoint. A sufficient condition for unimodularity is developed that is based upon the topological characteristics of the associated graph, and the results are applied to certain well-structured examples.
14 citations
01 Nov 1978
TL;DR: The models and the basic relations underlying the analysis as well as the method for evaluating packet delay and topological design methods are introduced together with the theoretical aspects on packet radio, satellite, and radio systems.
Abstract: With the intention of outlining some of the theoretical studies on the design of packet communication networks the present paper introduces the models and the basic relations underlying the analysis as well as the method for evaluating packet delay. Then the multicommodity flow problem as applied to the route assignment is described with particular reference to static and quasi-static routing schemes. Following this topological design methods are described in terms of capacity assignment, flow assignment, capacity and flow assignment, and topology, capacity and flow assignment. Theoritical studies on such factors as flow control and error control that affect the network throughput are also outlined together with the theoretical aspects on packet radio, satellite, and radio systems.
7 citations
01 Jun 1978
TL;DR: In this paper, the problem of reducing such signals to acceptable levels (i.e., hardening) has been studied for hardening systems to the effects of nuclear electromagnetic pulse (EMP) as well as other electromagnetic environments.
Abstract: The mathematical description of the response of a complex system such as an aircraft, a building, etc., to a general electromagnetic stimulus is a problem of exceeding difficulty. High confidence prediction of the signals at the various failure ports (normally pins) is in general beyond the state of the art. Related to the problem of failure-port signal predic tion there is the problem of reducing such signals to acceptable levels (i.e., hardening). This problem has serious implications for hardening systems to the effects of the nuclear electromagnetic pulse (EMP) as well as other electromagnetic environments.
3 citations
05 Nov 1978
TL;DR: The economics of medical computer networks are presented in context with the patient care and administrative goals of medical networks, with an emphasis on medical network design requirements in distributed data base design, telecommunications, satellite systems, and software engineering.
Abstract: The economics of medical computer networks are presented in context with the patient care and administrative goals of medical networks. Design alternatives and network topologies are discussed with an emphasis on medical network design requirements in distributed data base design, telecommunications, satellite systems, and software engineering. The success of the medical computer networking technology is predicated on the ability of medical and data processing professionals to design comprehensive, efficient, and virtually impenetrable security systems to protect data bases, network access and services, and patient confidentiality.
2 citations
22 Mar 1978
TL;DR: Analytical models are developed for determining the fraction of time that switching nodes have correct information as a function trajectory and speed of mobility, monitoring rate, traffic load, and network topology in a store-and-forward broadcast radio network with mobile switching nodes.
Abstract: A store-and-forward broadcast radio network with mobile switching nodes is considered. The problems of monitoring connectivity changes in the network and updating information in switching nodes to enable routing of messages, are addressed. Analytical models are developed for determining the fraction of time that switching nodes have correct information as a function trajectory and speed of mobility, monitoring rate, traffic load, and network topology. The problems are experimentally investigated and results of monitoring rate to obtain performance requirements are obtained.
1 citations
01 Jan 1978
TL;DR: In this paper, the authors explored the robustness of packet-switching over traditional circuit switching concepts for voice communications and demonstrated that network sizing as related to the number of voice channels traversing a particular transmission link, and network topology with respect to number of tandem links utilized in an end-to-end connection can have significant effects on the system performance.
Abstract: Various other studies have already indicated potential advantage of packet-switching over tradiational circuit-switching concepts for voice communications. This paper explores the robustness of such comparisons for a range of network architectures. In particular, it is demonstrated that network sizing as related to the number of voice channels traversing a particular transmission link, and network topology with respect to the number of tandem links utilized in an end-to-end connection can have significant effects on the system performance. Estimates for end-to-end delay and the efficiency of trunk utilization are developed as a function of network topology to provide the insight necessary to identify network design limitations. A number of packet-switching design approaches, ranging from a pure datagram to a circuit-switching-like mode, are also discussed together with their effects on overall performance.
TL;DR: The paper surveys the important developments in circuit theory during the last twenty- five years with a focus on general network analysis and synthesis methods.
Abstract: The paper surveys the important developments in circuit theory during the last twenty- five years. Areas covered are: General network analysis and synthesis methods, network topology, passive networks, active networks, digital filters, distributed-parameter networks, nonlinear networks, computer-aided analysis and synthesis methods and large-scale networks.
TL;DR: The major forecasts are the extensive use of electronic digital multiplex connecting networks, compatible with digital transmission systems, and the introduction of optical connecting techniques, which offer both compatibility with optical transmission and some interesting new possibilities for the size and configuration of switches.
Abstract: Developments are considered under the headings (i) connection techniques, (ii) control techniques, (hi) interaction of switching and transmission techniques, (iv) facilities offered, and (v) connecting network topology In each topic, there are open questions The major forecasts are: (i) the extensive use of electronic digital multiplex connecting networks, compatible with digital transmission systems; (ii) the introduction of optical connecting techniques, which offer both compatibility with optical transmission and some interesting new possibilities for the size and configuration of switches; (iii) the extensive use of stored program control; (iv) the supplementation of central processors by distributed control techniques for the common operational procedures, probably using microprocessors; and (v) the widespread use of semiconductor integrated circuits both for connection and control functions