Run Time Approximation of Non-blocking Service Rates for Streaming Systems

Stream processing is a compute paradigm that promises safe and efficient parallelism. Modern big-data problems are often well suited for stream processing's throughput-oriented nature. Realization of efficient stream processing requires monitoring and optimization of multiple communications links. Most techniques to optimize these links use queueing network models or network flow models, which require some idea of the actual execution rate of each independent compute kernel within the system. What we want to know is how fast can each kernel process data independent of other communicating kernels. This is known as the "service rate" of the kernel within the queueing literature. Current approaches to divining service rates are static. Modern workloads, however, are often dynamic. Shared cloud systems also present applications with highly dynamic execution environments (multiple users, hardware migration, etc.). It is therefore desirable to continuously re-tune an application during run time (online) in response to changing conditions. Our approach enables online service rate monitoring under most conditions, obviating the need for reliance on steady state predictions for what are probably non-steady state phenomena. First, some of the difficulties associated with online service rate determination are examined. Second, the algorithm to approximate the online non-blocking service rate is described. Lastly, the algorithm is implemented within the open source RaftLib framework for validation using a simple microbenchmark as well as two full streaming applications.Comment: technical repor

Inherent-Structure Dynamics and Diffusion in Liquids

The self-diffusion constant D is expressed in terms of transitions among the local minima of the potential (inherent structure, IS) and their correlations. The formulae are evaluated and tested against simulation in the supercooled, unit-density Lennard-Jones liquid. The approximation of uncorrelated IS-transition (IST) vectors, D_{0}, greatly exceeds D in the upper temperature range, but merges with simulation at reduced T ~ 0.50. Since uncorrelated IST are associated with a hopping mechanism, the condition D ~ D_{0} provides a new way to identify the crossover to hopping. The results suggest that theories of diffusion in deeply supercooled liquids may be based on weakly correlated IST.Comment: submitted to PR

University libraries and the postgraduate student: Physical and virtual spaces

Purpose – This study aims to examine the library/information issues affecting graduate students, both those on taught courses and those undertaking research. It seeks to focus specifically on their perceptions of the value to them of physical and digital resources and spaces, and how well their needs were being met. Design/methodology/approach – An online questionnaire survey of students was complemented by a series of face-to-face interviews with library staff. Findings – This group of students are different from undergraduates, whose information behaviour has more often been studied. They require silent study space, are enthusiastic book borrowers, and have limited interest in social media in the library. They have a strong requirement for digital resources and IT support, and are not inclined to ask for assistance from librarians. Research limitations/implications – The study is limited to three English universities, although they are sufficiently varied in nature to make the results more widely applicable. Practical implications – The survey provides evidence for librarians in universities and colleges serving graduate students as to the best form of provision, and for any library seeking to make best use of its space as resources become increasingly digital. Originality/value – This is one of the few studies to examine the information behaviour and needs of advanced students. It contributes to the debate on the future of the library as place in a digital age

Megawatt solar power systems for lunar surface operations

The work presented here shows that a solar power system can provide power on the order of one megawatt to a lunar base with a fairly high specific power. The main drawback to using solar power is still the high mass, and therefore, cost of supplying energy storage through the solar night. The use of cryogenic reactant storage in a fuel cell system, however, greatly reduces the total system mass over conventional energy storage schemes

Muon spin rotation studies of niobium for superconducting RF applications

In this work we investigate superconducting properties of niobium samples via application of the muon spin rotation/relaxation (muSR) technique. We employ for the first time the muSR technique to study samples that are cutout from large and small grain 1.5 GHz radio frequency (RF) single cell niobium cavities. The RF test of these cavities was accompanied by full temperature mapping to characterize the RF losses in each of the samples. Results of the muSR measurements show that standard cavity surface treatments like mild baking and buffered chemical polishing (BCP) performed on the studied samples affect their surface pinning strength. We find an interesting correlation between high field RF losses and field dependence of the sample magnetic volume fraction measured via muSR. The muSR line width observed in ZF-muSR measurements matches the behavior of Nb samples doped with minute amounts of Ta or N impurities. An upper bound for the upper critical field Hc2 of these cutouts is found.Comment: 20 pages, 14 figure

Toad (Anura: Bufonidae) Limb Abnormalities from an Aquatic Site in Scott, Pulaski County, Arkansas

We collected and examined 16 Fowler’s toads, Anaxyrus fowleri, and one dwarf American toad, Anaxyrus americanus charlesmithi, in central Arkansas in 2011. Collection was initiated by observation of abnormal toads. Toads were euthanized, measured, photographed, and deposited in the Arkansas State University herpetological collection. Several toads were radiographed. We found various abnormalities in both forelimbs and hindlimbs and on both sides of the body. The causes of the abnormalities remain unknown and will require further studies to determine if the environment is imperiled

Protocol for the United Kingdom Rotator Cuff Study (UKUFF) : a randomised controlled trial of open and arthroscopic rotator cuff repair

This project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02). J. L. Rees has received a grant from Oxford University which is related to this paper. J. Dawson reports that Oxford University has received a grant from HTA which is related to this paper, as well as a study grant.Peer reviewedPublisher PD

Molecular Identification of Eimeria Species in Broiler Chickens in Trinidad, West Indies

Coccidiosis is an intestinal disease of chickens of major economic importance to broiler industries worldwide. Species of coccidia found in chickens include Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox, and Eimeria tenella. In recent years, polymerase chain reaction (PCR) has been developed to provide accurate and rapid identification of the seven known Eimeria species of chickens. The aim of this study was to use species-specific real-time PCR (qPCR) to identify which of the seven Eimeria species are present in Trinidad poultry. Seventeen pooled fecal samples were collected from 6 broiler farms (2–5 pens per farm) across Trinidad. Feces were also collected from birds showing clinical signs of coccidiosis in two live bird markets (pluck shops). qPCR revealed the presence of five species of Eimeria (E. acervulina, E. maxima, E. mitis, E. necatrix, and E. tenella), but not E. brunetti or E. praecox. Mixed infections were detected on all broiler farms, and DNA of two highly pathogenic Eimeria species (E. tenella and E. necatrix) was detected in feces taken from clinically sick birds sampled from the two pluck shops

A review of alternatives for local government finance

Members of the present Government, including Mrs Thatcher, have in the past expressed their determination to scrap the present system of local rates. This determination appeared to be strengthened earlier in the year by the political storm that blew up over the rates revaluation in Scotland. Revaluation in Scotland had already been delayed two years beyond the normal statutory 5-year period and the delay only served to make an even larger jump in rateable values inevitable. The storm was the greater because the last revaluation in England and Wales was in 1973. This economic perspective reviews the present rating system and considers the alternatives which have been proposed by Government