The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform

Mb Eindhoven - One of the best experts on this subject based on the ideXlab platform.

Jiseung Nam - One of the best experts on this subject based on the ideXlab platform.

  • Performance evaluation of a picture archiving and communication network using stochastic activity networks
    IEEE transactions on medical imaging, 1993
    Co-Authors: William H. Sanders, Ralph Martinez, Yasser H. Alsafadi, Jiseung Nam
    Abstract:

    A fiber-optic star-based picture archiving and communication system (PACS) network that is based on a multiplexed passive star local area network with wavelength-division multiplexing (WDM) to provide separate logical Channels for transfer of control and image data is discussed. The system consists of an image network (INET), for image transfer at a rate of 140 Mb/s, and a control network (CNET), operating at 10 Mb/s, for mediating the flow of image transfers. INET is a circuit switched network devoted solely to image transfer, while CNET employs the CSMA/CD protocol for bus arbitration. Stochastic activity networks were used to develop a detailed model of the Command and image Channels. The performance of the system was then evaluated under realistic workload conditions. In particular, a number of important performance variables, including the image response time, Command Channel delay, and queue length at each type of node and the network supervisor, are estimated. The results (1) show that stochastic activity networks are an appropriate model type for evaluating picture archiving and communication systems, (2) delineate the workload conditions under which PACS may effectively operate, and (3) show that even when these conditions are exceeded, the Command Channel load remains extremely light. >

William H. Sanders - One of the best experts on this subject based on the ideXlab platform.

  • Performance evaluation of a picture archiving and communication network using stochastic activity networks
    IEEE transactions on medical imaging, 1993
    Co-Authors: William H. Sanders, Ralph Martinez, Yasser H. Alsafadi, Jiseung Nam
    Abstract:

    A fiber-optic star-based picture archiving and communication system (PACS) network that is based on a multiplexed passive star local area network with wavelength-division multiplexing (WDM) to provide separate logical Channels for transfer of control and image data is discussed. The system consists of an image network (INET), for image transfer at a rate of 140 Mb/s, and a control network (CNET), operating at 10 Mb/s, for mediating the flow of image transfers. INET is a circuit switched network devoted solely to image transfer, while CNET employs the CSMA/CD protocol for bus arbitration. Stochastic activity networks were used to develop a detailed model of the Command and image Channels. The performance of the system was then evaluated under realistic workload conditions. In particular, a number of important performance variables, including the image response time, Command Channel delay, and queue length at each type of node and the network supervisor, are estimated. The results (1) show that stochastic activity networks are an appropriate model type for evaluating picture archiving and communication systems, (2) delineate the workload conditions under which PACS may effectively operate, and (3) show that even when these conditions are exceeded, the Command Channel load remains extremely light. >

J L Zahradnik - One of the best experts on this subject based on the ideXlab platform.

  • Simulator for Evaluating Shoulder Motion as a Command Source for Fes Grasp Restoration Systems
    Archives of Physical Medicine and Rehabilitation, 1991
    Co-Authors: William K. Durfee, T R Mariano, J L Zahradnik
    Abstract:

    A simulator has been developed to evaluate the Command Channels through which a quadriplegic patient controls an upper limb neural prosthesis. The simulator consists of an animated grasping task implemented on a video screen. The patient controls the motion of an animated hand on the screen by moving his or her own hand while the animated hand opens and closes under control of the tested Command Channel. Experiments were performed using both able-bodied and quadriplegic subjects to evaluate shoulder motion as a Command-Channel source. The results demonstrated that optimal combinations of shoulder Command-Channel parameters are subject specific, which suggests using the simulator in the prescription of upper limb neural prostheses and in training quadriplegic persons who use them. Additionally, the experimental results quantified the reduction in performance that came from using ipsilateral vs contralateral shoulder control and the enhancement in performance realized when using substitute sensory force-feedback displays.

Boon-hee Soong - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of closed loop power control algorithms for a cellular DS/CDMA system
    IEE Proceedings - Communications, 1998
    Co-Authors: Moh Lim Sim, E. Gunawan, C.b. Soh, Boon-hee Soong
    Abstract:

    The authors consider the performance of a reverse link DS/CDMA system with fast closed loop power control algorithms. For power control purposes, the received signal-to-interference ratio (SIR) must be measured. A simple procedure is proposed for estimating received SIR which does not need much calibration. The result shows that the BER performance is sensitive to the feedback delay or the inverse of the power control updating frequency. The power control mechanism is effective provided that the power control Command updating frequency is ten times higher than the Doppler frequency. A step-size of 2dB for the single step-size power control algorithm is found to be optimal for the mobile unit's velocity, which is uniformly distributed in the range 0-100 km/h. It was also found that the BER performance is very sensitive to the power control Command Channel error rate in the range 10/sup -1/-10/sup -2/. This suggests that the system designer should concentrate on minimising this error to improve the overall performance. Lastly, if a multiple step-size power control algorithm is to be implemented, two power control Command bits would perform better than one, three, or more bits in a mobile Channel environment.

  • Study on the characteristics of predictive closed-loop power control algorithms for a cellular DS/CDMA system
    ICUPC '98. IEEE 1998 International Conference on Universal Personal Communications. Conference Proceedings (Cat. No.98TH8384), 1
    Co-Authors: Moh Lim Sim, E. Gunawan, C.b. Soh, Boon-hee Soong
    Abstract:

    This paper considers the performance of a reverse link DS/CDMA system with fast closed loop power control algorithms. A predictive power control algorithm is proposed and the performance is compared with the conventional single step-size algorithm. The effects of power control algorithm, power control updating frequency, power control Command Channel error rate, mobile unit's velocity and increment step-size on the system performance are investigated. Lastly, the optimum power control conditions are found and recommended.