808 research outputs found

    Dynamic Relevance Filtering in Asynchronous Transfer Mode-Based Distributed Interactive Simulation Exercises

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    As Distributed Interactive Simulation (DIS) exercises continue to grow in scale, the need to support a large number of players has become apparent. The demands on the network and the simulation hosts in large exercises, though, have proved to be prohibitive, requiring significant computational overhead to filter through the information and extract what is relevant to a particular simulation. Some mechanism is needed to reduce irrelevant network traffic received by a system, while increasing the bandwidth available for the DIS exercise. Previous research efforts in this area have centered primarily on fixed geographic partitions of the battlespace to reduce the traffic at a given host. This geographic partitioning cannot adapt to the changing battlespace, and requires relatively significant pre-exercise setup and coordination. Our research has been to implement a DIS exercise system using native ATM interfaces, and to determine if a dynamic partitioning system is feasible and will provide a sufficient reduction in network traffic to allow DIS exercises to scale to the target 100,000 entities. A support infrastructure for DIS over ATM was developed and tested with current AFIT DIS applications, and a prototype dynamic partitioning system using geographic criteria was implemented

    Red Drum and Spotted Seatrout Live-Release Tournament Mortality and Dispersal

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    Although catch-and-release fishing tournaments undoubtedly reduce mortality of target species, postrelease mortality and fish stockpiling at release sites remain common concerns related to these tournaments. The impacts of liverelease tournaments on freshwater species have been widely studied. However, research on estuarine sport fishes is lacking even though catch-and-release tournaments targeting these species are prevalent and popular recreational fisheries exist. Therefore, we estimated the post-weigh-in mortality and dispersal of Red Drum Sciaenops ocellatus and Spotted Seatrout Cynoscion nebulosus released from the 2016–2018 Alabama Deep Sea Fishing Rodeo live-weigh-in categories using acoustic telemetry. To concurrently estimate overall post-weigh-in mortality and dispersal, we used a Bayesian multistate model. Overall Red Drum post-weigh-in mortality (median = 6.12%; posterior credible interval [CrI] = 5.67–9.24%) was lower than overall Spotted Seatrout mortality (median = 30.63%; CrI = 26.74–40.00%). These estimates were within reported catch-and-release mortality ranges; however, they were higher than recent estimates for Spotted Seatrout. Within 1 week postrelease, Spotted Seatrout dispersal estimates (median = 87.03%; CrI = 72.96–95.72%) were higher than Red Drum (median = 55.62%; CrI = 42.75–68.10%) or Micropterus spp. in coastal and inland ecosystems. Long-term stockpiling at the release site was also not present; at the end of our 8-week observation period, median dispersal estimates were 94.41% (CrI = 87.15–98.19%) and 98.54% (CrI = 93.68–99.82%) for Red Drum and Spotted Seatrout, respectively. Red Drum fisheries may benefit most from live-release tournaments given that maximum mortality was \u3c10%, but Spotted Seatrout fisheries may also benefit, especially if considerations are made to further reduce tournament mortality. Although we do not know the ratio of tournament mortality to recreational harvest for these species, live-release tournaments may be able to relieve some harvest pressure on heavily exploited inshore marine fisheries and research validating their usefulness should continue

    Thermal Capacitance (Slug) Calorimeter Theory Including Heat Losses and Other Decaying Processes

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    A mathematical model, termed the Slug Loss Model, has been developed for describing thermal capacitance (slug) calorimeter behavior when heat losses and other decaying processes are not negligible. This model results in the temperature time slope taking the mathematical form of exponential decay. When data is found to fit well to this model, it allows a heat flux value to be calculated that corrects for the losses and may be a better estimate of the cold wall fully catalytic heat flux, as is desired in arc jet testing. The model was applied to the data from a copper slug calorimeter inserted during a particularly severe high heating rate arc jet run to illustrate its use. The Slug Loss Model gave a cold wall heat flux 15% higher than the value of 2,250 W/sq cm obtained from the conventional approach to processing the data (where no correction is made for losses). For comparison, a Finite Element Analysis (FEA) model was created and applied to the same data, where conduction heat losses from the slug were simulated. The heat flux determined by the FEA model was found to be in close agreement with the heat flux determined by the Slug Loss Model

    Scalable Mining of Common Routes in Mobile Communication Network Traffic Data

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    A probabilistic method for inferring common routes from mobile communication network traffic data is presented. Besides providing mobility information, valuable in a multitude of application areas, the method has the dual purpose of enabling efficient coarse-graining as well as anonymisation by mapping individual sequences onto common routes. The approach is to represent spatial trajectories by Cell ID sequences that are grouped into routes using locality-sensitive hashing and graph clustering. The method is demonstrated to be scalable, and to accurately group sequences using an evaluation set of GPS tagged data

    Building a personal symbolic space model from GSM CellID Positioning Data

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    Série : Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, vol. 7The context in which a person uses a mobile context-aware application can be described by many dimensions, including the, most popular, location and position. Some of the data used to describe these dimensions can be acquired directly from sensors or computed by reasoning algorithms. In this paper we propose to contextualize the mobile user of context-aware applications by describing his/her location in a symbolic space model as an alternative to the use of a position represented by a pair of coordinates in a geometric absolute referential. By exploiting the ubiquity of GSM networks, we describe a method to progressively create this symbolic and personal space model, and propose an approach to compute the level of familiarity a person has with each of the identified places. The validity of the developed model is evaluated by comparing the identified places and the computed values for the familiarity index with a ground truth represented by GPS data and the detailed agenda of a few persons

    Component-aware Orchestration of Cloud-based Enterprise Applications, from TOSCA to Docker and Kubernetes

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    Enterprise IT is currently facing the challenge of coordinating the management of complex, multi-component applications across heterogeneous cloud platforms. Containers and container orchestrators provide a valuable solution to deploy multi-component applications over cloud platforms, by coupling the lifecycle of each application component to that of its hosting container. We hereby propose a solution for going beyond such a coupling, based on the OASIS standard TOSCA and on Docker. We indeed propose a novel approach for deploying multi-component applications on top of existing container orchestrators, which allows to manage each component independently from the container used to run it. We also present prototype tools implementing our approach, and we show how we effectively exploited them to carry out a concrete case study

    Novel estimation of gear selectivity using a concurrent mass mortality event: A case study using red drum (Sciaenops ocellatus) in the northern Gulf of Mexico

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    Fishery-independent surveys are commonly used in modern stock assessment models to inform trends in abundance and these surveys may become more important when there are gaps in other data sources, such as harvest data. As a result of the federal harvest moratorium in the late 1980’s, Gulf of Mexico red drum (Sciaenops ocellatus) remains a data-limited species with little known about its post-escapement (6 – 46-year-old fish) abundance in offshore waters, which encompasses the spawning biomass of the stock. Historically, age and growth estimates were derived from purse seine collections, which was the industry\u27s preferred harvest technique. Recently, the addition of fishery-independent surveys, i.e. bottom longline surveys, sought to provide a potential alternative to purse seines; however, their efficacy in sampling the breadth of the offshore red drum population has not been widely evaluated. Here, we compared the age composition and selectivity of red drum collected with purse seine and bottom long line in offshore coastal waters of Mississippi and Alabama. Red drum collected in the purse seines ranged from 561 to 1018 mm total length (2–26 years old) and 770 − 1090 mm (2–36 years old) in bottom longlines. Additionally, an opportunistic sampling of red drum from a large fish kill in 2015 was used to estimate selectivity of red drum sampled by purse seine and bottom long line. Red drum selectivity generally decreased with age for the purse seine, while there was an increase in selectivity for the bottom long line survey. This novel approach using a mass mortality event to derive gear selectivity may allow fisheries scientists to refine selectivity measurements in stock assessments. Characterization of selectivity for different survey gears will allow for a more informed comparison of historic and current surveys when gear type effects change

    A new common functional coding variant at the DDC gene change renal enzyme activity and modify renal dopamine function.

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    The intra-renal dopamine (DA) system is highly expressed in the proximal tubule and contributes to Na+ and blood pressure homeostasis, as well as to the development of nephropathy. In the kidney, the enzyme DOPA Decarboxylase (DDC) originating from the circulation. We used a twin/family study design, followed by polymorphism association analysis at DDC locus to elucidate heritable influences on renal DA production. Dense single nucleotide polymorphism (SNP) genotyping across the DDC locus on chromosome 7p12 was analyzed by re-sequencing guided by trait-associated genetic markers to discover the responsible genetic variation. We also characterized kinetics of the expressed DDC mutant enzyme. Systematic polymorphism screening across the 15-Exon DDC locus revealed a single coding variant in Exon-14 that was associated with DA excretion and multiple other renal traits indicating pleiotropy. When expressed and characterized in eukaryotic cells, the 462Gln variant displayed lower Vmax (maximal rate of product formation by an enzyme) (21.3 versus 44.9 nmol/min/mg) and lower Km (substrate concentration at which half-maximal product formation is achieved by an enzyme.)(36.2 versus 46.8 μM) than the wild-type (Arg462) allele. The highly heritable DA excretion trait is substantially influenced by a previously uncharacterized common coding variant (Arg462Gln) at the DDC gene that affects multiple renal tubular and glomerular traits, and predicts accelerated functional decline in chronic kidney disease

    Research Tools to Investigate Movements, Migrations, and Life History of Sturgeons (Acipenseridae), with an Emphasis on Marine-Oriented Populations

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    Worldwide, sturgeons (Acipenseridae) are among the most endangered fishes due to habitat degradation, overfishing, and inherent life history characteristics (long life span, late maturation, and infrequent spawning). As most sturgeons are anadromous, a considerable portion of their life history occurs in estuarine and marine environments where they may encounter unique threats (e.g., interception in non-target fisheries). Of the 16 marine-oriented species, 12 are designated as Critically Endangered by the IUCN, and these include species commercially harvested. We review important research tools and techniques (tagging, electronic tagging, genetics, microchemistry, observatory) and discuss the comparative utility of these techniques to investigate movements, migrations, and life-history characteristics of sturgeons. Examples are provided regarding what the applications have revealed regarding movement and migration and how this information can be used for conservation and management. Through studies that include Gulf (Acipenser oxyrinchus desotoi) and Green Sturgeon (A. medirostris), we illustrate what is known about well-studied species and then explore lesser-studied species. A more complete picture of migration is available for North American sturgeon species, while European and Asian species, which are among the most endangered sturgeons, are less understood. We put forth recommendations that encourage the support of stewardship initiatives to build awareness and provide key information for population assessment and monitoring

    Blood Mercury Reporting in NHANES: Identifying Asian, Pacific Islander, Native American, and Multiracial Groups

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    INTRODUCTION: Asians, Pacific Islanders, and Native Americans are a potentially high-risk group for dietary exposure to methylmercury through fish consumption. However, blood mercury levels in this group have not been identified in recent reports of the National Health and Nutrition Examination Survey (NHANES) for the years 1999–2002. METHODS: We used NHANES data from 1999–2002 to obtain population estimates of blood mercury levels among women of childbearing age classified as belonging to the “other” racial/ethnic group (Asian, Pacific Islander, Native American, and multiracial; n = 140). Blood mercury levels in this group were compared with those among all other women participants, classified as Mexican American, non-Hispanic black, non-Hispanic white, and “other” Hispanic. RESULTS: An estimated 16.59 ± 4.0% (mean ± SE) of adult female participants who self-identified as Asian, Pacific Islander, Native American, or multiracial (n = 140) had blood mercury levels ≥5.8 μg/L, and 27.26 ± 4.22% had levels ≥3.5 μg/L. Among remaining survey participants (n = 3,497), 5.08 ± 0.90% had blood mercury levels ≥5.8 μg/L, and 10.86 ± 1.45% had levels ≥3.5 μg/L. CONCLUSIONS: Study subjects in NHANES who self-identified as Asian, Pacific Islander, Native American, or multiracial had a higher prevalence of elevated blood mercury than all other racial/ethnic participants in the survey. Future studies should address reasons for the high mercury levels in this group and explore possible interventions for lowering risk of methylmercury exposure in this population
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