2,051 research outputs found
Sprinklers: A Randomized Variable-Size Striping Approach to Reordering-Free Load-Balanced Switching
Internet traffic continues to grow exponentially, calling for switches that
can scale well in both size and speed. While load-balanced switches can achieve
such scalability, they suffer from a fundamental packet reordering problem.
Existing proposals either suffer from poor worst-case packet delays or require
sophisticated matching mechanisms. In this paper, we propose a new family of
stable load-balanced switches called "Sprinklers" that has comparable
implementation cost and performance as the baseline load-balanced switch, but
yet can guarantee packet ordering. The main idea is to force all packets within
the same virtual output queue (VOQ) to traverse the same "fat path" through the
switch, so that packet reordering cannot occur. At the core of Sprinklers are
two key innovations: a randomized way to determine the "fat path" for each VOQ,
and a way to determine its "fatness" roughly in proportion to the rate of the
VOQ. These innovations enable Sprinklers to achieve near-perfect load-balancing
under arbitrary admissible traffic. Proving this property rigorously using
novel worst-case large deviation techniques is another key contribution of this
work
Design and implementation of wire tension measurement system for MWPCs used in the STAR iTPC upgrade
The STAR experiment at RHIC is planning to upgrade the Time Projection
Chamber which lies at the heart of the detector. We have designed an instrument
to measure the tension of the wires in the multi-wire proportional chambers
(MWPCs) which will be used in the TPC upgrade. The wire tension measurement
system causes the wires to vibrate and then it measures the fundamental
frequency of the oscillation via a laser based optical platform. The platform
can scan the entire wire plane, automatically, in a single run and obtain the
wire tension on each wire with high precision. In this paper, the details about
the measurement method and the system setup will be described. In addition, the
test results for a prototype MWPC to be used in the STAR-iTPC upgrade will be
presented.Comment: 6 pages, 10 figues, to appear in NIM
Software Sustainability: The Modern Tower of Babel
<p>The aim of this paper is to explore the emerging definitions of software sustainability from the field of software engineering in order to contribute to the question, what is software sustainability?</p
A Core Set for people following lower limb amputation based on the International Classification of Functioning, Disability and Health
The International Classification of Functioning, Disability and Health (ICF) was endorsed by WHO in 2001 as a supplement to the International Classification of Diseases (ICD). This thesis reviews the concepts of human functioning and disability, the development of the International Classification of Impairments, Disabilities and Handicaps (ICIDH), the revision of ICIDH into the ICF and the challenges of its use. A systematic review of literature in relation to function of people with major lower limb amputation is presented and some of the common themes in function are identified. Qualitative studies on the perceptions of people with major lower limb amputation about functioning and disability were conducted at two international sites, and detailed comparisons and analyses of common functional ICF categories applicable to the outcomes from these groups were performed. A survey of clinician experts from around the world exploring the functional themes related to lower limb amputee functioning and health was conducted. Common ICF categories for this group of patients were identified. Lastly, a qualitative study using the ICF and a validated patient experience questionnaire in two different countries to examine functioning and disability in people with major lower limb amputation was conducted, allowing verification of the content validity of the ICF categories relevant to the participants. A comprehensive and a brief draft ICF Core Set for people with major lower limb amputation are presented as a result of this work
Categorising virtual water transfers through China's electric power sector
Water consumption in thermoelectric and hydropower plants in China increased from 1.6 and 6.1 billion m3, respectively, to 3.8 and 14.6 billion m3 from 2002 to 2010. Using the concept of virtual water, we attribute to different electricity users the total water consumption by the electric power sector. From 2002 to 2010, virtual water embodied in the final consumption of electricity (hereinafter referred to as VWEF) increased from 1.90 to 7.35 billion m3, whilst virtual water in electricity used by industries (hereinafter referred to as VWEI) increased from 5.82 to 11.13 billion m3. The inter-provincial virtual water trades as a result of spatial mismatch of electricity production and consumption are quantified. Nearly half (47.5% in 2010) of the physical water inputs into the power sector were virtually transferred across provincial boundaries in the form of virtual water embodied in the electricity produced, mainly from provinces in northeast, central and south China to those in east and north China. Until 2030, VWEF and VWEI are likely to increase from 5.27 and 14.89 billion m3 to 7.19 and 20.33 billion m3, respectively. Climate change mitigation and water conservation measures in the power sector may help to relieve the regional pressures on water resources imposed by the power sector
Modeling of an Interconnected Fluidized Bed Reactor for Chemical Looping Combustion
Chemical Looping Combustion (CLC) is comprised of two reactors, in which direct contact between air and fuel is avoided. A metal oxide, as oxygen carrier, transports oxygen from the air reactor to the fuel reactor while circulating between them. Based on the hydrodynamics coupled with reaction kinetics of oxygen carrier from the literature, a model for an interconnected fluidized bed reactor has been developed to optimize the design and operation of the reactor system. The model considers the chemical reaction of a single particle and a particle population balance for the calculation of bed particle conversion. The core-annulus and two-phase hydrodynamic models are assumed for the air and fuel reactors, respectively. Predictions of the oxygen emission, particle conversion and fuel conversion efficiency under different operating conditions are presented for a pilot scale CLC reactor system
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Layered SnS2-reduced graphene oxide composite--a high-capacity, high-rate, and long-cycle life sodium-ion battery anode material.
A layered SnS -reduced graphene oxide (SnS -RGO) composite is prepared by a facile hydrothermal route and evaluated as an anode material for sodium-ion batteries (NIBs). The measured electrochemical properties are a high charge specific capacity (630 mAh g at 0.2 A g ) coupled to a good rate performance (544 mAh g at 2 A g ) and long cycle-life (500 mAh g at 1 A g for 400 cycles). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 2 2 -1 -1 -1 -1 -1 -
MACHINE LEARNING ASSISTED QUICK EYESCAN (MLAQE) FOR SIGNAL INTEGRITY CHECK
Presented herein is a quick scan method for signal integrity checks through sampling of four points under certain thermal condition. The techniques presented herein use a machine learning trained model to ensure signal integrity check fidelity
Exploring the Performance Benefits of End-to-End Path Switching
This paper explores the feasibility of improving the performance of end-to-end data transfers between different sites through path switching. Our study is focused on both the logic that controls path switching decisions and the configurations required to achieve sufficient path diversity. Specifically, we investigate two common approaches offering path diversity – multi-homing and overlay networks – and investigate their characteristics in the context of a representative wide-area testbed. We explore the end-to-end delay and loss characteristics of different paths and find that substantial improvements can potentially be achived by path switching, especially in lowering end-to-end losses. Based on this assessment, we develop a simple path-switching mechanism capable of realizing those performance improvements. Our experimental study demonstrates that substantial performance improvements are indeed achievable using this approach
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