2,497 research outputs found

    Statistical Computations with AstroGrid and the Grid

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    We outline our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid. We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system. The broker will also interact with the AstroGrid workflow and MySpace environments. We present our planned usage of the VOTechBroker in computing a huge number of n-point correlation functions from the SDSS, as well as fitting over a million CMBfast models to the WMAP data.Comment: Invited talk to appear in "Proceedings of PHYSTAT05: Statistical Problems in Particle Physics, Astrophysics and Cosmology

    Massive Science with VO and Grids

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    There is a growing need for massive computational resources for the analysis of new astronomical datasets. To tackle this problem, we present here our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid (e.g. TeraGrid, COSMOS etc.). We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system. The broker will also interact with the AstroGrid workflow and MySpace environments. We discuss our planned usages of the VOTechBroker in computing a huge number of n-point correlation functions from the SDSS data and massive model-fitting of millions of CMBfast models to WMAP data. We also discuss other applications including the determination of the XMM Cluster Survey selection function and the construction of new WMAP maps.Comment: Invited talk at ADASSXV conference published as ASP Conference Series, Vol. XXX, 2005 C. Gabriel, C. Arviset, D. Ponz and E. Solano, eds. 9 page

    Recording of time-varying back-pain data: A wireless solution

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    Chronic back pain is a debilitating experience for a considerable proportion of the adult population, with a significant impact on countries’ economies and health systems. While there has been increasing anecdotal evidence to support the fact that for certain categories of patients (such as wheelchair users), the back pain experienced is dynamically varying with time, there is a relative scarcity of data to support and document this observation, with consequential impact upon such patients’ treatment and care. Part of the reason behind this state of affairs is the relative difficulty in gathering pain measurements at precisely defined moments in time. In this paper,we describe a wireless-enabled solution that collects both questionnaire and diagrammatic, visual-based data, via a pain drawing, which overcomes such limitations, enabling seamless data collection and its upload to a hospital server using existing wireless fidelity technology. Results show that it is generally perceived to be an easy-to-use and convenient solution to the challenges of anywhere/anytime data collection

    XSEDE Service Provider Software and Services Baseline v1.2

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    This document describes the Service Provider Software and Services of the XSEDE Production System Baseline (version 1.2). The objective of this document is therefore twofold: to describe the software and services which XSEDE service providers (SPs) may, and in some cases must deploy into their own environments; and to obtain community feedback on the suitability for purpose of these software and services, and in the manner of their descriptionNational Science Foundation OCI-1053575Ope

    Evaluating the impact of land use and policy on water quality in an agricultural catchment: The Leet water,South-East Scotland.

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    This is an interdisciplinary study combining research techniques from the natural and social sciences, to evaluate the impact of EU policies and land use change scenarios for assessing water quality in an agricultural catchment. The study focuses on the Leet Water catchment, a left-bank tributary of the River Tweed, Berwickshire, South-East Scotland. The Leet Water and its subcatchment the Lambden Bum cover an area of approximately 114km(^2) within the Lothian and Borders Nitrate Vulnerable Zone (designated in 2002).In the Leet Water catchment, spot measurements of nitrate (NO(^3)-N) from 1977 to 1998 found the 11.3 mg/1 (EU permitted maximum) was often exceeded. Further spot monitoring from October 2002 to August 2004 found 12 instances where the 11.3 mg/1 permitted maximum was exceeded with all streams in the catchment experiencing high levels of nitrate over the winter periods. Interviews with local farmers, advisors, and the regulators found this to be the result of a complex set of circumstances including long-term Common Agricultural Policy subsidies and the farmers' drive for increased profitability without due regard for the environmental consequences. Land management practices such as under- draining of fields, overuse of fertiliser and allowing livestock access to water-courses has exacerbated the problem. The study demonstrates the potential of multispectral airborne remote sensed data for mapping agricultural land cover at the field scale, including the ability to distinguish winter and spring-sown cereal crops. Pollution impacts were modelled using a modified export coefficient approach by integrating land cover with available chemical and fertiliser practice data sets. Results of modelling scenarios of simple land use changes found that reducing fertiliser use by 10% can reduce the number of fields in the very high risk group from 191 to 16 This equates to reducing the high risk area from 〜3255 ha (29% of the catchment) to 〜428 ha (3.3 % of the catchment). This method of water quality modelling provides a means of integrating field research on water quality with the results of socio-economic surveys. The research found the principal causes of the failure of EU policy to address the problems are both socio-economic and institutional barriers, in particular the way in which information is presented to the farming community. Case studies of both large and small farms reveal that agri-environment measures such as the 'points' based Rural Stewardship Scheme (RSS) can attract substantial funding. However, these schemes are of most benefit to large farms where significant land use changes that accrue points can be made. Smaller farms find it difficult to suggest changes that will accrue these 'points' for a successful application. Furthermore, farmers believe recent changes e.g. the Land Management Contract implemented by The Scottish Executive may include a range of funding opportunities for improving land management practices but these are not well presented. There are gaps in the knowledge transfer process in relation to water quality issues between Government and land users. This research suggests that independent facilitators (advisors) such as those used in the Australian landcare approach should be introduced in the UK to help address this problem

    Survey and Analysis of Production Distributed Computing Infrastructures

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    This report has two objectives. First, we describe a set of the production distributed infrastructures currently available, so that the reader has a basic understanding of them. This includes explaining why each infrastructure was created and made available and how it has succeeded and failed. The set is not complete, but we believe it is representative. Second, we describe the infrastructures in terms of their use, which is a combination of how they were designed to be used and how users have found ways to use them. Applications are often designed and created with specific infrastructures in mind, with both an appreciation of the existing capabilities provided by those infrastructures and an anticipation of their future capabilities. Here, the infrastructures we discuss were often designed and created with specific applications in mind, or at least specific types of applications. The reader should understand how the interplay between the infrastructure providers and the users leads to such usages, which we call usage modalities. These usage modalities are really abstractions that exist between the infrastructures and the applications; they influence the infrastructures by representing the applications, and they influence the ap- plications by representing the infrastructures

    Interoperable job submission and management with GridSAM, JMEA, and UNICORE

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    Achieving interoperability between Grid infrastructures is required by all us-ers consuming computing time for projects spanning across Grid domain boundaries. Standards naturally evolve slowly and on Grid level only a few have been proposed and widely accepted so far, among them JSDL. This pa-per describes how GridSAM which supports JSDL in combination with JMEA can be used to submit jobs to a UNICORE infrastructure and hence how the number of Grid projects accessible via GridSAM can be increased right now

    Modeling the spatial and temporal trends of water quality in boreal managed watersheds

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    Land use changes have altered natural hydrological pathways and biogeochemical cycling of carbon, nitrogen and phosphorus, among other elements, affecting the quality of aquatic ecosystems such as rivers, lakes and coastal areas. In this dissertation, the spatial and temporal trends of water quality variation in Finnish managed watersheds was studied by applying methods of multivariate statistics, time-series analysis, ecohydrological modeling and high-resolution geospatial data. The results show the complex effects of current land use, particularly agriculture, on stream water quality. New emerging trends of nutrient concentrations and loads were detected in the time-series analysis, such as an increase in the concentrations and loads of dissolved reactive phosphorus and total nitrogen, and a decrease in suspended sediment concentration in streams. This might be linked to the current erosion reduction strategy of land management for water protection. An ecohydrological modeling assessment showed an increasing downstream nutrient export from agricultural watershed under climate change scenarios. The modeling results also showed a potential nutrient export reduction by restoring potential biogeochemical hotspot areas - wet areas or areas prone to water saturation. These areas can function as nutrient sinks and enhance the watershed resiliency. High-resolution geospatial data allowed easier and more accurate mapping of wet areas as well as the extracting of their hydraulic characteristics. However, the ecohydrological models involved several sources of uncertainties, which need to be carefully addressed with extensive observational data, expert knowledge of model parameter definitions, proper modeling unit selection and empirical knowledge of the functioning of the studied watershed system. The results of this dissertation highlight the importance of combined methods for watershed management research, and the proper identification of the biophysical processes in the modeling of non-point pollutant sources; this can in turn lead to an efficient water protection measure, and restoring biogeochemical hotspot areas within the watershed.Vedenlaadun alueellisten ja ajallisten vaihteluiden mallintaminen viileän vyöhykkeen valuma-alueilla. Maankäytön muutokset ovat vaikuttaneet luonnollisiin hydrologisiin prosesseihin sekä hiilen, typen ja fosforin biogeokemiallisiin kiertoihin. Nämä puolestaan vaikuttavat vesiekosysteemien tilaan joissa, järvissä ja rannikkoalueella. Väitöstutkimuksessa tutkittiin vedenlaadun alueellisia ja ajallisia muutoksia suomalaisessa maaseutumaisemassa käyttäen monimuuttujamenetelmiä, aikasarja-analyysejä, ekohydrologista mallinnusta ja erotuskyvyltään tarkkoja paikkatietoaineistoja. Tulokset todentavat maatalouteen kytkeytyvien maankäytön piirteiden kompleksisia vaikutuksia jokivesien laatuun. Aikasarja-analyysit osoittivat myös aiemmin tuntemattomia trendejä jokivesien ravinteiden määrissä ja pitoisuuksissa, esimerkkeinä liuenneen reaktiivisen fosforin määrän ja pitoisuuden lisääntyminen sekä sedimenttisuspension väheneminen; molemmat eroosion vähentämiseen tähtäävien vesiensuojelutoimien seurauksena. Ekohydrologinen mallinnus osoitti myös sen, että ravinteiden huuhtoutuminen maatalousvaltaisilla valuma-alueilla lisääntyy ilmastonmuutoksen seurauksena. Tulokset kannustavat biogeokemiallisten avainalueiden, kuten kosteikkojen ja vettä keräävien painanteiden kunnostamiseen, jolloin ravinteiden huuhtoutuminen vähenee. Ravinnenieluina toimiessaan ne voivat myös parantaa valumaalueen ekologista kestävyyttä ja palautumiskykyä. Tutkimuksessa osoitettiin myös erotuskyvyltään tarkkojen paikkatietoaineistojen hyödyllisyys avainalueiden kartoituksessa ja alueiden hydrologisten ominaisuuksien tunnistamisessa. Ekohydrologiseen mallinnukseen sisältyy toisaalta myös epävarmuustekijöitä, joihin tulisi paneutua vielä kattavammin hyödyntäen asiantuntijatietoa parametrien täsmentämisessä, määrittämällä tarkennettuja mallinnusyksiköitä tai hyödyntäen empiirisiä tutkimustietoja valuma-alueen toiminnasta. Väitöstutkimus osoittaa myös sen, miten erilaisten tutkimusmenetelmien yhdistely vahvistaa valuma-aluetarkastelua ja siihen liittyen erilaisten biofysikaalisten prosessien ymmärtämistä ja keskeisten päästölähteiden mallintamista. Näin muodoin yhdistelmämenetelmien käyttö tukee entistä tehokkaampien vesiensuojelutoimien kehittämistä ja valumaalueiden biogeokemiallisten avainalueiden kunnostamistaModelado de las tendencias temporales y espaciales de la calidad del agua en cuencas hidrográficas boreales manejados. El cambio del uso del suelo ha alterado los procesos hidrológicos naturales y los ciclos biogeoquímicos del carbono, el nitrógeno y el fósforo, entre otros elementos, afectando directamente la calidad de los ecosistemas acuáticos como los ríos, lagos y zonas costeras. En esta disertación, las tendencias espaciales y temporales de la variación de la calidad del agua en cuencas hidrográficas finlandesas se estudiaron mediante la aplicación de métodos de estadística multivariante, análisis de series de tiempo, modelos ecohidrológicos y datos geoespaciales de alta resolución. Los resultados muestran los efectos complejos del uso actual del suelo, particularmente la agricultura, en la calidad del agua de los ríos y corrientes. Se detectaron nuevas tendencias emergentes de concentraciones y cargas de nutrientes en el análisis de series temporales, como un aumento en la concentración y carga del fósforo disuelto reactive y nitrógeno total, y una disminución en la concentración de sedimentos en suspensión en los ríos y corrientes. Esto podría estar vinculado a la estrategia actual de manejo del suelo, orientado a la reducción de la erosión para la protección del agua. Una evaluación a través de modelización ecohidrológica mostró un aumento de la exportación de nutrientes aguas abajo de la cuenca agrícola bajo escenarios de cambio climático. Los resultados de la modelización también mostraron una posible reducción de la exportación de nutrientes mediante la restauración de posibles zonas críticas biogeoquímicas: áreas húmedas o áreas propensas a la saturación de agua. Estas áreas pueden funcionar como sumideros de nutrientes y mejorar la resiliencia de la cuenca. Los datos geoespaciales de alta resolución permitieron un fácil y más preciso cartografiado de las áreas húmedas, así como la extracción de sus características hidráulicas. Sin embargo, los modelos ecohidrológicos involucraron varias fuentes de incertidumbre, que deben abordarse cuidadosamente con bastantes datos de observación, conocimiento experto de las definiciones de los parámetros del modelo, selección adecuada de la unidad de modelado y conocimiento empírico del funcionamiento del sistema de la cuenca estudiada. Los resultados de esta disertación destacan la importancia de los métodos combinados para la investigación de gestión de cuencas hidrográficas y la identificación adecuada de los procesos biofísicos en la modelización de fuentes contaminantes difusas; esto a su vez puede conducir a una medidaeficiente de protección del agua, y restauración de áreas claves de alta función biogeoquímica dentro de la cuenca
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