441,362 research outputs found

    Art meets science – empowering stroke patients to regain muscular control through creative graphics technology, psycho-physiology and neuroplasticity.

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    Treating patients with a cerebrovascular accident or stroke is complicated by severity and site of brain lesion. Muscular control is lost when neural pathways are interrupted or damaged due to embolus, thrombosis or ruptured aneurysm. Return of movement is further hindered by sustained spasticity of muscle groups or inflammation or severance to functionally important neural pathways. Neuro-feedback mechanisms have been explored in the past with some success. A new, improved and innovative method is presented that makes use of psycho-physiology techniques providing immediate visual, auditory and neurological feedback via a fast switching device that relays neuro-muscular movement during rehabilitative tasks and exercises. Visual and auditory signals enable the patient to make use of neurological activity in a purposeful manner, re-directing it to particular tasks. Concentrating on a series of tones elicited via a computer console and by vigilance of changing visual graphics displays allows the patient to accurately control unwanted activity and enables the body to re-learn previously damaged neural circuits. Patients gaining the ability to re-direct and re-route neural pathways have made significant gains in returning function to their leg muscles, particularly to the quadriceps group. These are very often the first groups of muscles to be affected during stroke and make the patient wheelchairbound and often permanently disabled. Occupational and social functioning is affected and quality of life is altered. Patients who are able to re-gain posture and re-learn to walk are empowered and have a better chance of returning to social and occupational settings. Trials in the United Kingdom have shown significant benefits for patients using neuro-feedback. Significant success by these patients has provided researchers with the potential benefits of using neuro-feedback in rehabilitation and increases our scientific and clinical knowledge of neuro-plasticity in even the large muscle groups of the damaged human body. This technology bridges creative artistic graphics technology with thorough evidencebased science

    Fast, Accurate and Detailed NoC Simulations

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    Network-on-Chip (NoC) architectures have a wide variety of parameters that can be adapted to the designer's requirements. Fast exploration of this parameter space is only possible at a high-level and several methods have been proposed. Cycle and bit accurate simulation is necessary when the actual router's RTL description needs to be evaluated and verified. However, extensive simulation of the NoC architecture with cycle and bit accuracy is prohibitively time consuming. In this paper we describe a simulation method to simulate large parallel homogeneous and heterogeneous network-on-chips on a single FPGA. The method is especially suitable for parallel systems where lengthy cycle and bit accurate simulations are required. As a case study, we use a NoC that was modelled and simulated in SystemC. We simulate the same NoC on the described FPGA simulator. This enables us to observe the NoC behavior under a large variety of traffic patterns. Compared with the SystemC simulation we achieved a speed-up of 80-300, without compromising the cycle and bit level accuracy

    QoS routing in ad-hoc networks using GA and multi-objective optimization

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    Much work has been done on routing in Ad-hoc networks, but the proposed routing solutions only deal with the best effort data traffic. Connections with Quality of Service (QoS) requirements, such as voice channels with delay and bandwidth constraints, are not supported. The QoS routing has been receiving increasingly intensive attention, but searching for the shortest path with many metrics is an NP-complete problem. For this reason, approximated solutions and heuristic algorithms should be developed for multi-path constraints QoS routing. Also, the routing methods should be adaptive, flexible, and intelligent. In this paper, we use Genetic Algorithms (GAs) and multi-objective optimization for QoS routing in Ad-hoc Networks. In order to reduce the search space of GA, we implemented a search space reduction algorithm, which reduces the search space for GAMAN (GA-based routing algorithm for Mobile Ad-hoc Networks) to find a new route. We evaluate the performance of GAMAN by computer simulations and show that GAMAN has better behaviour than GLBR (Genetic Load Balancing Routing).Peer ReviewedPostprint (published version

    A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

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    This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

    The dynamics of iterated transportation simulations

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    Iterating between a router and a traffic micro-simulation is an increasibly accepted method for doing traffic assignment. This paper, after pointing out that the analytical theory of simulation-based assignment to-date is insufficient for some practical cases, presents results of simulation studies from a real world study. Specifically, we look into the issues of uniqueness, variability, and robustness and validation. Regarding uniqueness, despite some cautionary notes from a theoretical point of view, we find no indication of ``meta-stable'' states for the iterations. Variability however is considerable. By variability we mean the variation of the simulation of a given plan set by just changing the random seed. We show then results from three different micro-simulations under the same iteration scenario in order to test for the robustness of the results under different implementations. We find the results encouraging, also when comparing to reality and with a traditional assignment result. Keywords: dynamic traffic assignment (DTA); traffic micro-simulation; TRANSIMS; large-scale simulations; urban planningComment: 24 pages, 7 figure

    Using microsimulation feedback for trip adaptation for realistic traffic in Dallas

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    This paper presents a day-to-day re-routing relaxation approach for traffic simulations. Starting from an initial planset for the routes, the route-based microsimulation is executed. The result of the microsimulation is fed into a re-router, which re-routes a certain percentage of all trips. This approach makes the traffic patterns in the microsimulation much more reasonable. Further, it is shown that the method described in this paper can lead to strong oscillations in the solutions.Comment: Accepted by International Journal of Modern Physics C. Complete postscript version including figures in http://www-transims.tsasa.lanl.gov/research_team/papers
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