1,697 research outputs found
An enhanced random early marking algorithm for Internet flow control
Get PDFWe propose earlier an optimization based flow control for the Internet called Random Early Marking (REM). In this paper we propose and evaluate an enhancement that attempts to speed up the convergence of REM in the face of large feedback delays. REM can be regarded as an implementation of an optimization algorithm in a distributed network. The basic idea is to treat the optimization algorithm as a discrete time system and apply linear control techniques to stabilize its transient. We show that the modified algorithm is stable globally and converges exponentially locally. This algorithm translates into an enhanced REM scheme and we illustrate the performance improvement through simulation
"Kia Mauri Tau!" Narratives of recovery from disabling mental health problems
Get PDFA bicultural research team at the University of Waikato successfully applied for funding from the Health Research Council to do a qualitative research project in the area of ‘pathways to wellness’. The Mental Health Narratives Project set out to gather forty narratives of mental ill health, recovery and life after recovery by interviewing Maori and non-Maori women and men who once had a disabling mental health problem. We aimed to describe journeys to mental health, identify key themes in accounts of the recovery process and describe the impact of the experience of mental ill health on life after recovery
Optimization flow control -- I: Basic algorithm and convergence
Get PDFWe propose an optimization approach to flow control where the objective is to maximize the aggregate source utility over their transmission rates. We view network links and sources as processors of a distributed computation system to solve the dual problem using a gradient projection algorithm. In this system, sources select transmission rates that maximize their own benefits, utility minus bandwidth cost, and network links adjust bandwidth prices to coordinate the sources' decisions. We allow feedback delays to be different, substantial, and time varying, and links and sources to update at different times and with different frequencies. We provide asynchronous distributed algorithms and prove their convergence in a static environment. We present measurements obtained from a preliminary prototype to illustrate the convergence of the algorithm in a slowly time-varying environment. We discuss its fairness property
Scottish railway policy : past, present - and future?
Get PDFThe major thrust of this briefing paper is to evaluate current and past railwaypolicy and to outline proposals which can overcome previous policy failures. Muchof the discussion on railway policy has involved little more than posturing by themain political parties. Despite protestations to the contrary, their actual policies when in power have been remarkably similar. It is argued here that much of the contentious nature of the debate over railway policy can be resolved by a reappraisal of some fundamental economic attributes of railway services. On the basis of this reappraisal, suggestions are made for the possible restructuring of railway services and the implications of such proposals for Scottish railway services are explored
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