David F. Robinson

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This paper addresses the problem of one-to-many, or multicast, communication in wormhole-routed, n-dimensional torus networks. The proposed methods are designed for systems that support intermediate reception, which permits multi-destination messages to be pipelined through several nodes, depositing a copy at each node. A key issue in the design of such(More)
Massively parallel computers (MPC) are characterized by the distribution of memory among an ensemble of nodes. Since memory is physically distributed, MPC nodes communicate by sending data through a network. In order to program an MPC, the user may directly invoke low-level message passing primitives, may use a higher-level communications library, or may(More)
This paper presents efficient algorithms that implement one-to-many, or multicast, communication in wormhole-routed torus networks. By exploiting the properties of the switching technology and the use of virtual channels, a minimum-time multicast algorithm is presented for n-dimensional torus networks that use deterministic, dimension-ordered routing of(More)
Intensity-modulated radiation therapy (IMRT) requires the determination of the appropriate multileaf collimator settings to deliver an intensity map. The purpose of this work was to attempt to reduce the number of segments required for IMRT delivery and the number of monitor units required to deliver an intensity map. An intensity map may be written as a(More)
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. ABSTRACT High-resolution spectroscopy at energies below 1 keV covers the(More)
This paper addresses the problem of collective data distribution, speciically multicast, in wormhole-routed hypercubes. The system model allows a processor to send and receive data in all dimensions simultaneously. New theoretical results that characterize contention among messages in wormhole-routed hypercubes are developed and used to design new multicast(More)
The authors analyze competing forces affecting the diffusion of telemedicine practices across organizations, potential learning effects from telemedicine practice, and their implications for the development of telemedicine-based networks. They also speculate on the learning, diffusion, and institutional effects that telemedical collaboration may trigger;(More)
This paper addresses the problem of collective data distribution, speciically multicast, in wormhole-routed hypercubes. The system model allows a processor to send and receive data in all dimensions simultaneously. New theoretical results that characterize contention among messages in wormhole-routed hypercubes are developed and used to design new multicast(More)
may be freely shared among individuals, but it may not be republished in any medium without express written consent from the authors and advance notification of the editor. Abstract In this paper we present time series data collected from a café run by business students at a Midwestern public university. The data were collected over a ten-week period during(More)