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Proposals for new data quality objectives to underpin ambient air quality monitoring networks

ACCREDITATION AND QUALITY ASSURANCE 2014年第6期19卷 465-471页

作者： Brown, Richard J. C. Woods, Peter T. Natl Phys Lab Analyt Sci Div Teddington TW11 0LW Middx England

The data completeness requirements for the production of defensible annual averages of air quality parameters are discussed. data quality objectives concerning time coverage and data capture specified by current legislation are critically examined, and the improved, combined metric of data coverage is proposed. Best practice proposals to ensure the representativeness of air quality data across the calendar year are presented. These are based on minimising any bias between the annual average calculated using the data acquired and the annual average that would have been calculated if data coverage had been 100 %. In all cases, the optimum solution is for air quality network operators to aim for 100 % data coverage.

关键词： data quality Annual average Air quality European legislation data coverage

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Study on Cloud data Destruction Mechanism and its Application

Study on Cloud Data Destruction Mechanism and its Applicatio...

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2nd International Conference on Applied Mechanics and Materials (ICAMM 2013)

作者： Wu Jing Zhao Fengzhi Dong Yudan Northeast Petr Univ Daqing 1163318 Heilongjiang Peoples R China

ISBN: (纸本)9783037859841

The cloud data security is the primary concern users, especially in multi-tenant cloud environments residual data can cause data leakage problem, but most of the cloud service providers do not provide data processing residual solution. This study was designed HDFS multi- level security mechanisms and data destruction and data based on bidirectional heartbeat overwrite technology combined with the data from the destruction mechanism to ensure effective destruction of data under the premise of safety requirements and performance can be achieved demand balance.

关键词： Cloud Computing data Security data coverage

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data CENTRIC MULTI-SHIFT SENSOR SCHEDULING FOR WIRELESS SENSOR NETWORKS

DATA CENTRIC MULTI-SHIFT SENSOR SCHEDULING FOR WIRELESS SENS...

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IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Zhang, Jialin Hu, Yu Hen Univ Wisconsin Madison WI 53706 USA

ISBN: (纸本)9781479903566

A multi-shift sensor scheduling method is proposed to extend the operating lifespan of a wireless sensor network. Sensor nodes in the WSN are partitioned into N subnetworks and the operating schedule is partitioned into N shifts of equal duration. Exploiting spatial correlations among sensor nodes, data collected using each subnetwork can well approximate the data collected using original sensor network. Each subnetwork also form a connected component to ensure proper data collection. This task is formulated as a NP-hard constrained subset selection problem. A polynomial time heuristic algorithm leveraging breath-first search and subspace approximation is proposed. Simulations using a real world data set demonstrate superior performance and extended lifespan of this proposed method.

关键词： Wireless sensor networks node scheduling data coverage connectivity

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Selecting informative subsets of sparse supermatrices increases the chance to find correct trees

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BMC BIOINFORMATICS 2013年第1期14卷 1-13页

作者： Misof, Bernhard Meyer, Benjamin von Reumont, Bjorn Marcus Kueck, Patrick Misof, Katharina Meusemann, Karen Zool Forsch Museum Alexander Koenig Zmb D-53113 Bonn Germany Univ Klinikum Hamburg Eppendorf Inst Systemat Neurowissensch D-20246 Hamburg Germany Nat Hist Museum London Dept Life Sci London SW7 5BD England Australian Natl Insect Collect CSIRO Ecosyst Sci Acton ACT Australia

Background: Character matrices with extensive missing data are frequently used in phylogenomics with potentially detrimental effects on the accuracy and robustness of tree inference. Therefore, many investigators select taxa and genes with high data coverage. Drawbacks of these selections are their exclusive reliance on data coverage without consideration of actual signal in the data which might, thus, not deliver optimal data matrices in terms of potential phylogenetic signal. In order to circumvent this problem, we have developed a heuristics implemented in a software called mare which (1) assesses information content of genes in supermatrices using a measure of potential signal combined with data coverage and (2) reduces supermatrices with a simple hill climbing procedure to submatrices with high total information content. We conducted simulation studies using matrices of 50 taxa x 50 genes with heterogeneous phylogenetic signal among genes and data coverage between 10-30%. Results: With matrices of 50 taxa x 50 genes with heterogeneous phylogenetic signal among genes and data coverage between 10-30% Maximum Likelihood (ML) tree reconstructions failed to recover correct trees. A selection of a data subset with the herein proposed approach increased the chance to recover correct partial trees more than 10-fold. The selection of data subsets with the herein proposed simple hill climbing procedure performed well either considering the information content or just a simple presence/absence information of genes. We also applied our approach on an empirical data set, addressing questions of vertebrate systematics. With this empirical dataset selecting a data subset with high information content and supporting a tree with high average boostrap support was most successful if information content of genes was considered. Conclusions: Our analyses of simulated and empirical data demonstrate that sparse supermatrices can be reduced on a formal basis outperforming the usually

关键词： data coverage Correct Tree Hill Climbing data Subset Tree Reconstruction

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Granular fuzzy models: A study in knowledge management in fuzzy modeling

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INTERNATIONAL JOURNAL OF APPROXIMATE REASONING 2012年第7期53卷 1061-1079页

作者： Pedrycz, Witold Song, Mingli Univ Alberta Dept Elect & Comp Engn Edmonton AB T6R 2V4 Canada King Abdulaziz Univ Fac Engn Dept Elect & Comp Engn Jeddah 21589 Saudi Arabia Polish Acad Sci Syst Res Inst PL-01447 Warsaw Poland

In system modeling, knowledge management comes vividly into the picture when dealing with a collection of individual models. These models being considered as sources of knowledge, are engaged in some collective pursuits of a collaborative development to establish modeling outcomes of global character. The result comes in the form of a so-called granular fuzzy model, which directly reflects upon and quantifies the diversity of the available sources of knowledge (local models) involved in knowledge management. In this study, several detailed algorithmic schemes are presented along with related computational aspects associated with Granular Computing. It is also shown how the construction of information granules completed through the use of the principle of justifiable granularity becomes advantageous in the realization of granular fuzzy models and a quantification of the quality (specificity) of the results of modeling. We focus on the design of granular fuzzy models considering that the locally available models are those fuzzy rule-based. It is shown that the model quantified in terms of two conflicting criteria, that is (a) a coverage criterion expressing to which extent the resulting information granules "cover" include data and (b) specificity criterion articulating how detailed (specific) the obtained information granules are. The overall quality of the granular model is also assessed by determining an area under curve (AUC) where the curve is formed in the coverage-specificity coordinates. Numeric results are discussed with intent of displaying the most essential features of the proposed methodology and algorithmic developments. (C) 2012 Elsevier Inc. All rights reserved.

关键词： Information granules Knowledge management Granular fuzzy model Principle of justifiable granularity Information specificity data coverage

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CSEM inversion:Impact of anisotropy,data coverage,and initial models

CSEM inversion:Impact of anisotropy,data coverage,and initia...

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The 19th International Workshop on Electromagnetic Induction in the Earth

作者： Charlie JING Ken GREEN Dennis WILLEN ExxonMobil Upstream Research Company HoustonUSA

While 3-D inversion is a particularly effective tool for interpreting marine CSEM data,3-D data acquisition is needed to image the resistivity structure of an anisotropic *** on synthetic models show resistivity artifacts when anisotropic data are forced through isotropic inversion and when offline data are excluded from anisotropic *** artifacts appear also when the inversion starting model differs too much from the actual *** a result,inadequate attention to anisotropy or inadequate data coverage can lead directly to misinterpretation of the subsurface resistivity *** imaging with good data coverage,accurate receiver orientation,and good initial resistivity models are necessary to quantitatively image resistive anomalies in an anisotropic earth.

关键词： CSEM anisotropic inversion conductivity anisotropy data coverage

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Interference Behavior of Integrated Femto and Macrocell Environments

Interference Behavior of Integrated Femto and Macrocell Envi...

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2011 IFIP Wireless Days (WD)

作者： Alexiou, Antonios Bouras, Christos Kokkinos, Vasileios Kontodimas, Konstantinos Papazois, Andreas Univ Patras Comp Engn & Informat Dept GR-26110 Patras Greece

ISBN: (纸本)9781457720284

Femtocells are data access points installed by the subscribers to provide better indoor voice and data coverage and to increase system capacity. The integrated femtocell/macrocell networks offer an efficient way to increase access capacity by improving coverage and quality of service while on the other side the deployment cost for the service provider is kept in extremely low levels. One of the major technical challenges that femtocell networks are facing is their interference behavior when they are placed within macrocells. The study presented in this paper focuses on the impact of integrating femtocells in macrocell networks in terms of adjacent cell interference that the macrocell environment adds to users served by a femto base station and vice versa. To this direction, we have designed and implemented a simulation testbed that estimates the cross-tier interference and the throughput in every point of an integrated femtocell/macrocell Long Term Evolution-Advanced (LTE-A) network.

关键词： Analytical models Antennas Estimation Interference LTE-A network Long Term Evolution Macrocell networks Signal to noise ratio Throughput cross-tier interference data coverage femto base station femtocell femtocellular radio indoor radio indoor voice inter

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Availability and coverage of hydrologic data in the US geological survey National Water Information System (NWIS) and US Environmental Protection Agency Storage and Retrieval System (STORET)

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EARTH SCIENCE INFORMATICS 2008年第3-4期1卷 119-129页

作者： Beran, Bora Piasecki, Michael Drexel Univ Dept Civil Architectural & Environm Engn Philadelphia PA 19104 USA Microsoft ESci Grp San Francisco CA 94105 USA

The need for a unified and improved data access system for the nation's vast hydrologic data holdings has increased over the past few years as researchers strive for better understanding the human impact on the nation's water cycle. Large mission oriented data repositories such as the USGS' National Water Information System (NWIS) and EPA's Storage and Retrieval System (EPA STORET) play a crucial role in providing a substantial amount of the nationwide coverage, however they do differ regionally in terms of coverage (parameters) and geospatial data density. Besides the differences in geographic distribution, repositories tend to undergo changes in mission statements and as such have different foci in their data collection activities that change as time progresses. This paper places the two water information systems next to each in an attempt to work out the differences in terms of coverage and content and how they complement each other when overlaid. This is done through the use of a number the CUAHSI Hydrologic Information Systems components, namely a web-service suite called WaterOneFlow that permits interrogation of the available data content of a national water metadata catalogue into which these two information systems have been integrated.

关键词： databases data coverage NWIS STORET WaterOneFlow Web-services

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Estimating net air-sea fluxes from ocean bulk data: Methodology and application to the heat cycle

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GLOBAL BIOGEOCHEMICAL CYCLES 2001年第4期15卷 767-782页

作者： Gloor, M Gruber, N Hughes, TMC Sarmiento, JL Princeton Univ Atmospher & Ocean Sci Program Princeton NJ 08544 USA

A novel method to estimate annual mean heat, water, and gas exchange fluxes between the ocean and the atmosphere is proposed that is complementary to the traditional approach based on air-sea gradients and bulk exchange parameterization. The new approach exploits the information on surface exchange fluxes contained in the distribution of temperature, salinity, and dissolved gases in the ocean interior. We use an Ocean General Circulation Model to determine how the distribution in the ocean interior is linked to surface fluxes. We then determine with least squares the surface fluxes that are most compatible with the observations. To establish and test the method, we apply it to ocean temperature data to estimate heat fluxes across the air-sea interface for which a number of climatological estimates exists. We also test the sensitivity of the inversion results to data coverage, differences in ocean transport, variations in the surface flux pattern and a range of spatial resolutions. We find, on the basis of the World Ocean Circulation Experiment (WOCE) data network augmented with selected high-quality pre-WOCE data, that we are able to constrain heat exchange fluxes for 10-15 regions of the ocean, whereby these fluxes nearly balance globally without enforcing a conservation constraint. Our results agree well with heat flux estimates on the basis of bulk exchange parameterization, which generally require constraints to ensure a global net heat flux of zero. We also find that the heat transports implied by our inversely estimated fluxes are in good agreement with a large range of heat transport estimates based on hydrographic data. Increasing the number of regions beyond the 10-15 regions considered here is severely limited because of modeling errors. The inverse method is fairly robust to the modeling of the spatial patterns of the surface fluxes;however, it is quite sensitive to the modeling of ocean transport. The most striking difference between our estimates and th

关键词： .annual mean gas exchange exchange parameterization ocean interior Ocean General Circulation Model heat fluxes inversion results data coverage ocean transport World Ocean

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