Sample records for spatial olap application

  1. Easier surveillance of climate-related health vulnerabilities through a Web-based spatial OLAP application

    Microsoft Academic Search

    Eveline Bernier; Pierre Gosselin; Thierry Badard; Yvan Bédard

    2009-01-01

    BACKGROUND: Climate change has a significant impact on population health. Population vulnerabilities depend on several determinants of different types, including biological, psychological, environmental, social and economic ones. Surveillance of climate-related health vulnerabilities must take into account these different factors, their interdependence, as well as their inherent spatial and temporal aspects on several scales, for informed analyses. Currently used technology includes

  2. Efficient Polygon Amalgamation Methods for Spatial OLAP and Spatial Data Mining

    Microsoft Academic Search

    Xiaofang Zhou; David Truffet; Jiawei Han

    1999-01-01

    . The polygon amalgamation operation computes the boundaryof the union of a set of polygons. This is an important operationfor spatial on-line analytical processing and spatial data mining, wherepolygons representing different spatial objects often need to be amalgamatedby varying criteria when the user wants to aggregate or reclassifythese objects. The processing cost of this operation can be very highfor a

  3. A New Relational Spatial OLAP Approach For Multi-resolution and Spatio-multidimensional Analysis of Incomplete Field Data

    E-print Network

    Boyer, Edmond

    data (Bédard, Merrett et al. 2001). These technologies extend Data Warehouse (DW) and OLAP systems information using the vector model (Bédard, Rivest et al. 2007). SOLAP technology can be applied in different

  4. ERATOSTHENES: Design and Architecture of an OLAP System

    Microsoft Academic Search

    Nikos Karayannidis; Panos Vassiliadis; Aris Tsois; Timos Sellis

    Abstract . On-Line Analytical Processing (OLAP) is a trend i n database technology, based on the multidimensional view of data. The aim, of this paper is twofold: (a) to list general problems and solutions applicable to the de,sign of any OLAP system and (b) to present the specific design decisions that we made,for a prototype under development at NTUA, which

  5. Object-Based Selective Materialization for Efficient Implementation of Spatial Data Cubes

    Microsoft Academic Search

    Nebojsa Stefanovic; Jiawei Han; Krzysztof Koperski

    2000-01-01

    With a huge amount of data stored in spatial databases and the introduction of spatial components to many relational or object-relational databases, it is important to study the methods for spatial data warehousing and OLAP of spatial data. In this paper, we study methods for spatial OLAP, by integration of nonspatial OLAP methods with spatial database implementation techniques. A spatial

  6. Evaluation of SOVAT: An OLAP-GIS decision support system for community health assessment data analysis

    Microsoft Academic Search

    Matthew Scotch; Bambang Parmanto; Valerie Monaco

    2008-01-01

    BACKGROUND: Data analysis in community health assessment (CHA) involves the collection, integration, and analysis of large numerical and spatial data sets in order to identify health priorities. Geographic Information Systems (GIS) enable for management and analysis using spatial data, but have limitations in performing analysis of numerical data because of its traditional database architecture. On-Line Analytical Processing (OLAP) is a

  7. Design of the ERATOSTHENES OLAP Server

    Microsoft Academic Search

    Nikos Karayannidis; Aris Tsois; Panos Vassiliadis; Timos K. Sellis

    2001-01-01

    On-Line Analytical Processing (OLAP) is a trend in database technology, based on the multidimensional view of data and is\\u000a an indispensable component of the so-called business intelligence technology. The systems that realize this technology are called OLAP servers and are among the most high-priced products in software industry today [24]. The aim of this paper is twofold: (a) to describe

  8. Integrating OLAP and Ranking: The Ranking-Cube Methodology

    Microsoft Academic Search

    Dong Xin; Jiawei Han

    2007-01-01

    OLAP (On-Line Analytical Processing) and Rank- ing are currently separate technologies in the database systems. OLAP emphasizes on e-cient multi- dimensional data analysis and ranking is good for ef- fective data exploration in massive data. In this paper, we discuss the problem of integrating OLAP and rank- ing, such that ranking serves as a function block for data analysis and

  9. Data Warehousing: Data Models and OLAP operations

    E-print Network

    Raghavan, Vijay

    . This enables management to gain a consistent picture of the business. #12;Data Warehouse Architecture #12;Other DBMS to store and manage warehouse data ­ OLAP middleware to support missing pieces (2: Compare and Contrast 9. Conclusion #12;Understanding the term Data Warehousing · Data Warehouse: The term

  10. OLAP Over Uncertain and Imprecise Data

    Microsoft Academic Search

    Douglas Burdick; Prasad M. Deshpande; T. S. Jayram; Raghu Ramakrishnan; Shivakumar Vaithyanathan

    2005-01-01

    We extend the OLAP data model to represent data ambiguity, specifically imprecision and uncertainty, and introduce an allocation-based approach to the semantics of aggregation queries over such data. We identify three natural query properties and use them to shed light on alternative query semantics. While there is much work on representing and querying ambiguous data, to our knowledge this is

  11. Summarizability in OLAP and Statistical Data Bases

    Microsoft Academic Search

    Hans-joachim Lenz; Arie Shoshani

    1997-01-01

    Summarizability of OLAP and Statistical Databases is an a extremely important property because violating this condition can lead to erroneous conclusions and decisions. In this paper we explore the conditions for summarizability. We introduce a framework for specifying precisely the context in which statistical objects are defined. We use a three step process to define normalized statistical objects. Using this

  12. Range Queries in OLAP Data Cubes

    Microsoft Academic Search

    Ching-Tien Ho; Rakesh Agrawal; Nimrod Megiddo; Ramakrishnan Srikant

    1997-01-01

    A range query applies an aggregation operation over all selectedcells of an OLAP data cube where the selection isspecified by providing ranges of values for numeric dimensions.We present fast algorithms for range queries for twotypes of aggregation operations: SUM and MAX. These twooperations cover techniques required for most popular aggregationoperations, such as those supported by SQL.For range-sum queries, the essential

  13. Effectiveness of OLAP-Based Sales Analysis in Retail Enterprises

    Microsoft Academic Search

    Chunhua Ju; Minghua Han

    2008-01-01

    Data warehouse and online analytical processing (OLAP) are two significant information technology (IT) strategies. To commercial enterprises, merchandise sales play important and special role. With the market competition getting fierce, managers see information as a critical resource and require methods that let them exploit it for competitive advantage. The development of data warehouse and OLAP make it possible to use

  14. Graph OLAP: Towards Online Analytical Processing on Graphs

    Microsoft Academic Search

    Chen Chen; Xifeng Yan; Feida Zhu; Jiawei Han; Philip S. Yu

    2008-01-01

    OLAP (On-Line Analytical Processing) is an important notion in data analysis. Recently, more and more graph or networked data sources come into being. There exists a sim- ilar need to deploy graph analysis from different perspec- tives and with multiple granularities. However, tradition al OLAP technology cannot handle such demands because it does not consider the links among individual data

  15. Designing and Implementing OLAP Systems from XML Documents

    Microsoft Academic Search

    Franck Ravat; Olivier Teste; Ronan Tournier; Gilles Zurfluh

    There has been a lot of research on OLAP (On-Line Analytical Pro- cessing) systems during the past decade. These systems allow decision makers to improve their decisions. Despite numerous multidimensional conceptual models, none tackle the problem of analysing data extracted from text-rich XML documents. These documents represent a lot of unavailable information for actual OLAP sys- tems. Moreover, the implementation

  16. Criminal Incident Data Association Using the OLAP Technology

    Microsoft Academic Search

    Song Lin; Donald E. Brown

    2003-01-01

    Associating criminal incidents committed by the same person is important in crime analysis. In this paper, we introduce concepts\\u000a from OLAP (online-analytical processing) and data-mining to resolve this issue. The criminal incidents are modeled into an\\u000a OLAP data cube; a measurement function, called the outlier score function is defined on the cube cells. When the score is\\u000a significant enough, we

  17. Discovery-Driven Exploration of OLAP Data Cubes

    Microsoft Academic Search

    Sunita Sarawagi; Rakesh Agrawal; Nimrod Megiddo

    1998-01-01

    .Analysts predominantly use OLAP data cubes to identifyregions of anomalies that may represent problem areas or new opportunities.The current OLAP systems support hypothesis-driven explorationof data cubes through operations such as drill-down, roll-up, and selection.Using these operations, an analyst navigates unaided through ahuge search space looking at large number of values to spot exceptions.We propose a new discovery-driven exploration paradigm that

  18. Spatial Disease Surveillance: Methods and Applications

    E-print Network

    Zhang, Tonglin

    Chapter 15 Spatial Disease Surveillance: Methods and Applications Tonglin Zhang 15.1 Introduction the realistic investigation of spatial variation in disease risks, particular at the small unit level. Recently Centers for Disease Control and Prevention (CDC). Due to the reason of privacy, CDC does not announce

  19. OLAP: A Fast, Easy, Affordable Executive Information System--Finally!

    ERIC Educational Resources Information Center

    Stewart, Henry M.

    1995-01-01

    The University of Rochester's experience with online analytical processing (OLAP), part of its executive information system, is reported. The server, a multiuser, local area network (LAN)-based database loaded from legacy systems or a data warehouse, can rapidly manipulate and display data, and allows quick creation and changing of analytical…

  20. Topic Cube: Topic Modeling for OLAP on Multidimensional Text Databases

    Microsoft Academic Search

    Duo Zhang; Chengxiang Zhai; Jiawei Han

    2009-01-01

    As the amount of textual information grows explosively in vari- ous kinds of business systems, it becomes more and more desir- able to analyze both structured data records and unstructured text data simultaneously. While online analytical processing (OLAP) techniques have been proven very useful for analyzing and mining structured data, they face challenges in handling text data. On the other

  1. An overview of data warehousing and OLAP technology

    Microsoft Academic Search

    Surajit Chaudhuri; Umeshwar Dayal

    1997-01-01

    Data warehousing and on-line analytical processing (OLAP) are essential elements of decision support, which has increasingly become a focus of the database industry. Many commercial products and services are now available, and all of the principal database management system vendors now have offerings in these areas. Decision support places some rather different requirements on database technology compared to traditional on-line

  2. View discovery in OLAP databases through statistical combinatorial optimization

    SciTech Connect

    Hengartner, Nick W [Los Alamos National Laboratory; Burke, John [PNNL; Critchlow, Terence [PNNL; Joslyn, Cliff [PNNL; Hogan, Emilie [PNNL

    2009-01-01

    OnLine Analytical Processing (OLAP) is a relational database technology providing users with rapid access to summary, aggregated views of a single large database, and is widely recognized for knowledge representation and discovery in high-dimensional relational databases. OLAP technologies provide intuitive and graphical access to the massively complex set of possible summary views available in large relational (SQL) structured data repositories. The capability of OLAP database software systems to handle data complexity comes at a high price for analysts, presenting them a combinatorially vast space of views of a relational database. We respond to the need to deploy technologies sufficient to allow users to guide themselves to areas of local structure by casting the space of 'views' of an OLAP database as a combinatorial object of all projections and subsets, and 'view discovery' as an search process over that lattice. We equip the view lattice with statistical information theoretical measures sufficient to support a combinatorial optimization process. We outline 'hop-chaining' as a particular view discovery algorithm over this object, wherein users are guided across a permutation of the dimensions by searching for successive two-dimensional views, pushing seen dimensions into an increasingly large background filter in a 'spiraling' search process. We illustrate this work in the context of data cubes recording summary statistics for radiation portal monitors at US ports.

  3. Selective Materialization: An Efficient Method for Spatial Data Cube Construction

    Microsoft Academic Search

    Jiawei Han; Nebojsa Stefanovic; Krzysztof Koperski

    1998-01-01

    . On-line analytical processing (OLAP) has gained its popularityin database industry. With a huge amount of data stored in spatialdatabases and the introduction of spatial components to many relationalor object-relational databases, it is important to study the methods forspatial data warehousing and on-line analytical processing of spatialdata. In this paper, we study methods for spatial OLAP, by integrationof nonspatial on-line

  4. IX-Cubes: Iceberg Cubes for Data Warehousing and OLAP on XML Data

    E-print Network

    Pei, Jian

    IX-Cubes: Iceberg Cubes for Data Warehousing and OLAP on XML Data Fianny Ming-fei Jian The Chinese is not available. In this paper, we introduce the IX-cube (Iceberg XML cube) over XML data to tackle the problem. We extend OLAP operations to XML data. We also develop efficient approaches to IX-Cube computation

  5. Nonparametric Spatial Models for Extremes: Application to Extreme Temperature Data.

    E-print Network

    Reich, Brian J.

    to make inference about spatial extreme events, we introduce a new nonparametric model for extremes. WeNonparametric Spatial Models for Extremes: Application to Extreme Temperature Data. Montserrat, increase energy con- sumption, and lead to hazardous health conditions. Thus, understanding and predicting

  6. The Application of Qualitative Spatial Reasoning to GIS \\Lambda

    E-print Network

    Leeds, University of

    The Application of Qualitative Spatial Reasoning to GIS \\Lambda (extended abstract) Brandon Bennett relations, being asymmetric, have inverses denoted, R \\Gamma1 .) DC(A;B) A B PO(A;B) B A TPP(A;B) A B EQ of Tarski (1938), Bennett (1994) has shown how a significant class of spatial relations can be encoded

  7. Hedonic approaches based on spatial econometrics and spatial statistics: application to evaluation of project benefits

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Morito; Seya, Hajime

    2009-12-01

    This study discusses the theoretical foundation of the application of spatial hedonic approaches—the hedonic approach employing spatial econometrics or/and spatial statistics—to benefits evaluation. The study highlights the limitations of the spatial econometrics approach since it uses a spatial weight matrix that is not employed by the spatial statistics approach. Further, the study presents empirical analyses by applying the Spatial Autoregressive Error Model (SAEM), which is based on the spatial econometrics approach, and the Spatial Process Model (SPM), which is based on the spatial statistics approach. SPMs are conducted based on both isotropy and anisotropy and applied to different mesh sizes. The empirical analysis reveals that the estimated benefits are quite different, especially between isotropic and anisotropic SPM and between isotropic SPM and SAEM; the estimated benefits are similar for SAEM and anisotropic SPM. The study demonstrates that the mesh size does not affect the estimated amount of benefits. Finally, the study provides a confidence interval for the estimated benefits and raises an issue with regard to benefit evaluation.

  8. APPLICATION OF SPATIAL INFORMATION TECHNOLOGY TO PETROLEUM RESOURCE ASSESSMENT ANALYSIS.

    USGS Publications Warehouse

    Miller, Betty M.; Domaratz, Michael A.

    1984-01-01

    Petroleum resource assessment procedures require the analysis of a large volume of spatial data. The US Geological Survey (USGS) has developed and applied spatial information handling procedures and digital cartographic techniques to a recent study involving the assessment of oil and gas resource potential for 74 million acres of designated and proposed wilderness lands in the western United States. The part of the study which dealt with the application of spatial information technology to petroleum resource assessment procedures is reviewed. A method was designed to expedite the gathering, integrating, managing, manipulating and plotting of spatial data from multiple data sources that are essential in modern resource assessment procedures.

  9. Developing Access Control Model of Web OLAP over Trusted and Collaborative Data Warehouses

    NASA Astrophysics Data System (ADS)

    Fugkeaw, Somchart; Mitrpanont, Jarernsri L.; Manpanpanich, Piyawit; Juntapremjitt, Sekpon

    This paper proposes the design and development of Role- based Access Control (RBAC) model for the Single Sign-On (SSO) Web-OLAP query spanning over multiple data warehouses (DWs). The model is based on PKI Authentication and Privilege Management Infrastructure (PMI); it presents a binding model of RBAC authorization based on dimension privilege specified in attribute certificate (AC) and user identification. Particularly, the way of attribute mapping between DW user authentication and privilege of dimensional access is illustrated. In our approach, we apply the multi-agent system to automate flexible and effective management of user authentication, role delegation as well as system accountability. Finally, the paper culminates in the prototype system A-COLD (Access Control of web-OLAP over multiple DWs) that incorporates the OLAP features and authentication and authorization enforcement in the multi-user and multi-data warehouse environment.

  10. Compiling Data Intensive Applications with Spatial Coordinates

    Microsoft Academic Search

    Renato Ferreira; Gagan Agrawal; Ruoming Jin; Joel H. Saltz

    2000-01-01

    Processing and analyzing large volumes of data plays an increasingly important role in many domains of scientific research.\\u000a We are developing a compiler which processes data intensive applications written in a dialect of Java and compiles them for\\u000a efficient execution on cluster of workstations or distributed memory machines.\\u000a \\u000a In this paper, we focus on data intensive applications with two important

  11. A Multidimensional and Multiversion Structure for OLAP Applications

    E-print Network

    Song, Il-Yeol

    , 69621 Villeurbanne, France +33 4 72 43 84 83 miquel@if.insa-lyon.fr Yvan Bédard CRG Université Laval, Qc, G1K7P4, Canada +1 418 656-5491 yvan.bedard@scg.ulaval.ca Anne Tchounikine LISI-INSA de Lyon Bâtiment

  12. Spatial extended hazard model with application to prostate cancer survival.

    PubMed

    Li, Li; Hanson, Timothy; Zhang, Jiajia

    2015-06-01

    This article develops a Bayesian semiparametric approach to the extended hazard model, with generalization to high-dimensional spatially grouped data. County-level spatial correlation is accommodated marginally through the normal transformation model of Li and Lin (2006, Journal of the American Statistical Association 101, 591-603), using a correlation structure implied by an intrinsic conditionally autoregressive prior. Efficient Markov chain Monte Carlo algorithms are developed, especially applicable to fitting very large, highly censored areal survival data sets. Per-variable tests for proportional hazards, accelerated failure time, and accelerated hazards are efficiently carried out with and without spatial correlation through Bayes factors. The resulting reduced, interpretable spatial models can fit significantly better than a standard additive Cox model with spatial frailties. PMID:25521422

  13. FROM TRANSACTIONAL SPATIAL DATABASES INTEGRITY CONSTRAINTS TO SPATIAL DATACUBES INTEGRITY CONSTRAINTS

    E-print Network

    CONSTRAINTS M. Salehi a,b, *, Y. Bédard a,b , M.A. Mostafavi a , J. Brodeur c a Center for Research Databases for Decision Support Laval University, Quebec City, Canada mehrdad.salehi.1@ulaval.ca, (yvan.bedard making and leads to an efficient DSS tool known as Spatial OLAP (SOLAP) (Bédard, Rivest et al. 2006

  14. Research Article Towards spatial data quality information analysis tools for experts

    E-print Network

    data quality analysis. This paper presents the design of such a tool that can manage heterogeneous data, multi-granularity and context-sensitive spatial data quality indicators that help experts to build this approach. Keywords: Spatial data quality; Fitness for use; Visualization; Indicators; Spatial OLAP

  15. High spatial resolution probes for neurobiology applications

    NASA Astrophysics Data System (ADS)

    Gunning, D. E.; Kenney, C. J.; Litke, A. M.; Mathieson, K.

    2009-06-01

    Position-sensitive biological neural networks, such as the brain and the retina, require position-sensitive detection methods to identify, map and study their behavior. Traditionally, planar microelectrodes have been employed to record the cell's electrical activity with device limitations arising from the electrode's 2-D nature. Described here is the development and characterization of an array of electrically conductive micro-needles aimed at addressing the limitations of planar electrodes. The capability of this array to penetrate neural tissue improves the electrode-cell electrical interface and allows more complicated 3-D networks of neurons, such as those found in brain slices, to be studied. State-of-the-art semiconductor fabrication techniques were used to etch and passivate conformally the metal coat and fill high aspect ratio holes in silicon. These are subsequently transformed into needles with conductive tips. This process has enabled the fabrication of arrays of unprecedented dimensions: 61 hexagonally close-packed electrodes, ˜200 ?m tall with 60 ?m spacing. Electroplating the tungsten tips with platinum ensure suitable impedance values (˜600 k? at 1 kHz) for the recording of neuronal signals. Without compromising spatial resolution of the neuronal recordings, this array adds a new and exciting dimension to the study of biological neural networks.

  16. OLAP on Information Networks: a new Framework for Dealing with Bibliographic Data

    E-print Network

    Paris-Sud XI, Université de

    , social and in- formation systems on the web have become ubiquitous and their volume has increased every, published in "1st International Workshop on Social Business Intelligence (SoBI 2013), Genoa : Italy (2013OLAP on Information Networks: a new Framework for Dealing with Bibliographic Data Wararat Jakawat

  17. SOCQET: Semantic OLAP with Compressed Cube and Summarization Laks V.S. Lakshmanan

    E-print Network

    Pei, Jian

    SOCQET: Semantic OLAP with Compressed Cube and Summarization Laks V.S. Lakshmanan Jian Pei Yan Zhao cube, which can be viewed as a multi-level, multi-dimensional database with aggregate data at multiple granularity. In a data cube, two basic semantic relations among cells are roll up and drill down. A cell c1

  18. Application of Spatial Statistics to Ionosphere Estimation for WAAS

    E-print Network

    Stanford University

    Application of Spatial Statistics to Ionosphere Estimation for WAAS Juan Blanch, Todd Walter, Per be required to increase performance substantially is the ionospheric correction algorithm. WAAS incorporates information from reference stations to create a correction map of the ionosphere. More importantly, this map

  19. The Application of Qualitative Spatial Reasoning to GIS

    E-print Network

    Bennett, Brandon

    The Application of Qualitative Spatial Reasoning to GIS (extended abstract) Brandon Bennett relations, being asymmetric, have inverses denoted, R 1 .) DC(A;B) A B PO(A;B) B A TPP(A;B) A B EQ of entailments in this language in nite time. However,exploitingthe results of Tarski (1938), Bennett(1994) has

  20. Multiresolutional filter application for spatial information fusion in robot navigation

    Microsoft Academic Search

    Özer Ciftcioglu

    2008-01-01

    robot navigation is described. The novelty of the research is the enhanced estimation of the spatial sensory information in autonomous robotics by means of wavelet decomposition into multiresolutional levels and the fusion of the processed information while the processing takes place at the respective levels. Although wavelet-based information fusion is used in different applications (Hong, L., 1994; Hsin, H.C. &

  1. Bayesian approaches for adaptive spatial sampling : an example application.

    SciTech Connect

    Johnson, R. L.; LePoire, D.; Huttenga, A.; Quinn, J.

    2005-05-25

    BAASS (Bayesian Approaches for Adaptive Spatial Sampling) is a set of computational routines developed to support the design and deployment of spatial sampling programs for delineating contamination footprints, such as those that might result from the accidental or intentional environmental release of radionuclides. BAASS presumes the existence of real-time measurement technologies that provide information quickly enough to affect the progress of data collection. This technical memorandum describes the application of BAASS to a simple example, compares the performance of a BAASS-based program with that of a traditional gridded program, and explores the significance of several of the underlying assumptions required by BAASS. These assumptions include the range of spatial autocorrelation present, the value of prior information, the confidence level required for decision making, and ''inside-out'' versus ''outside-in'' sampling strategies. In the context of the example, adaptive sampling combined with prior information significantly reduced the number of samples required to delineate the contamination footprint.

  2. DESARROLLO DE UN LENGUAGE DE CONSULTA PARA LA INTEGRACION DE GIS Y OLAP Pgina 1 Tesis de Licenciatura en Ciencias de la Computacin

    E-print Network

    Figueira, Santiago

    Licenciatura en Ciencias de la Computación DESARROLLO DE UN LENGUAGE DE CONSULTA PARA INTEGRACION DE SISTEMAS DE INFORMACION GEOGRAFICA (GIS ) Y ON LINE ANALYTICAL PROCESSING (OLAP) Sebastián Javier Zich Agosto GIS Y OLAP Página 2 RESUMEN La presente tesis describe una propuesta de integración de sistemas de

  3. SPATIAL DATA ANALYSIS WITH GIS: AN INTRODUCTION TO APPLICATION IN THE SOCIAL

    E-print Network

    California at Santa Barbara, University of

    SPATIAL DATA ANALYSIS WITH GIS: AN INTRODUCTION TO APPLICATION IN THE SOCIAL SCIENCES by Luc). #12;SPATIAL DATA ANALYSIS WITH GIS: AN INTRODUCTION TO APPLICATION IN THE SOCIAL SCIENCES INTRODUCTION of a Geographic Information System (GIS), which makes it a natural tool to aid in the analysis of spatial data. I

  4. Adaptive Spatial Resolution Control Scheme for Mobile Video Applications

    Microsoft Academic Search

    Yonghee Lee; Heejung Lee; Heonshik Shin

    2007-01-01

    Video streams can be compressed to fit the available network by controlling three factors; temporal resolution, spatial resolution and picture quality. Controlling picture quality by modifying the quantization parameter (QP) is most widely used. But we demonstrate that reducing the spatial resolution is more effective in a low bit-rate environment, and we show how to find the optimal spatial resolution

  5. Spatial Scan Statistics: Models,Calculations, and Applications

    Microsoft Academic Search

    Martin Kulldorff

    \\u000a A common problem in spatial statistics is whether a set of points are randomly distributed or if they show signs of clusters\\u000a or clustering. When the locations of clusters are of interest, it is natural to use a spatial scan statistic.\\u000a \\u000a \\u000a Different spatial scan statistics have been proposed. These are discussed and presented in a general framework that incorporates\\u000a two-dimensional

  6. Spatial point pattern analysis and its application in geographical epidemiology

    Microsoft Academic Search

    Anthony C Gatrell; Trevor C Bailey; Peter J Diggle; Barry S Rowlingson

    1996-01-01

    This paper reviews a number of methods for the exploration and modelling of spatial point patterns with particular reference to geographical epidemiology (the geographical incidence of disease). Such methods go well beyond the conventional 'nearest-neighbour' and 'quadrat' analyses which have little to offer in an epidemiological context because they fail to allow for spatial variation in population density. Correction for

  7. Clustering algorithms are attractive for the task of class iden tification in spatial databases. However, the application to

    E-print Network

    Hinneburg, Alexander

    satellite images, X­ray crystallography or other automatic equipment. Therefore, automated know­ ledge databases. However, the application to large spatial databases rises the following requirements, Efficiency on Large Spatial Databases, Handling Noise. 1. Introduction Numerous applications require

  8. Clustering algorithms are attractive for the task of class iden-tification in spatial databases. However, the application to

    E-print Network

    Ester, Martin

    satellite images, X-ray crystallography or other automatic equipment. Therefore, automated know- ledge databases. However, the application to large spatial databases rises the following requirements, Efficiency on Large Spatial Databases, Handling Noise. 1. Introduction Numerous applications require

  9. Application of Fourier analysis to multispectral/spatial recognition

    NASA Technical Reports Server (NTRS)

    Hornung, R. J.; Smith, J. A.

    1973-01-01

    One approach for investigating spectral response from materials is to consider spatial features of the response. This might be accomplished by considering the Fourier spectrum of the spatial response. The Fourier Transform may be used in a one-dimensional to multidimensional analysis of more than one channel of data. The two-dimensional transform represents the Fraunhofer diffraction pattern of the image in optics and has certain invariant features. Physically the diffraction pattern contains spatial features which are possibly unique to a given configuration or classification type. Different sampling strategies may be used to either enhance geometrical differences or extract additional features.

  10. Application of the Phase Light Modulator in the Image Optical Encryption Scheme with Spatially Incoherent Illumination

    NASA Astrophysics Data System (ADS)

    Bondareva, A. P.; Evtikhiev, N. N.; Krasnov, V. V.; Starikov, S. N.

    2015-01-01

    We describe application of the phase liquid-crystal spatial light modulator HoloEyePLUTOVIS as an encoding element in the image optical encryption scheme with spatially incoherent illumination. Optical encryption and numerical decryption of test images were conducted. The results of experiments demonstrate the efficiency of the constructed optical encryption scheme.

  11. Efficient Computations for Gaussian Markov Random Field Models with two Applications in Spatial Epidemiology

    E-print Network

    Rue, Håvard

    to take advantage of more modern techniques for sparse matrices compared to more classical bandEfficient Computations for Gaussian Markov Random Field Models with two Applications in Spatial on two problems in spatial epidemiology. The first is a semi-parametric ecological regression problem

  12. Application of spatial frequency response as a criterion for evaluating thermal imaging camera performance

    Microsoft Academic Search

    Andrew Lock; Francine Amon

    2008-01-01

    Police, firefighters, and emergency medical personnel are examples of first responders that are utilizing thermal imaging cameras in a very practical way every day. However, few performance metrics have been developed to assist first responders in evaluating the performance of thermal imaging technology. This paper describes one possible metric for evaluating spatial resolution using an application of Spatial Frequency Response

  13. SPATIAL VARIABILITY IN PHOSPHORUS BEFORE AND AFTER POULTRY MANURE APPLICATION IN SMALL PLOTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate assessment of environmental research on small plots requires knowledge of the spatial variability in soil properties at small spatial scales. The effect of management practices, such as manure application, can affect this variability and should be accounted for in small plot studies. The ...

  14. TerraHS: Integration of Functional Programming and Spatial Databases for GIS Application

    E-print Network

    Camara, Gilberto

    in imperative languages such as C++ and Java. This is especially true for spatial databases, where applications.2 A Brief Tour of the Haskell Syntax Functions are the core of Haskell. A simple example is a function

  15. Application of a spatial dynamic model to urban populations.

    PubMed

    Pumain, D

    1988-01-01

    The author applies P. Allen's intra-urban model "to the post-war evolution of the spatial distribution of employment and resident active population in a few French urban agglomerations. [She makes] a short presentation of the structure and of the main properties of this complex model. The results of the calibrations and the residuals of the simulations are then analysed." PMID:12341862

  16. Spatial sharpening of land surface temperature for daily energy balance applications

    NASA Astrophysics Data System (ADS)

    Cammalleri, Carmelo; Ciraolo, Giuseppe; Minacapilli, Mario

    2008-10-01

    Daily high spatial resolution assessment of actual evapotranspiration is essential for water management and crop water requirement estimation under stress conditions. The application of energy balance models usually requires satellite observations of radiometric surface temperature with high geometrical and temporal resolutions. By now, however, high spatial resolution (~ 100 m) is available with low time frequency (approximately every two weeks); at the opposite daily acquisition are characterised by poor spatial resolution. The analysis of vegetation index (VI) and land surface temperature (LST) spatial relationship, shows in substance a scale invariant behaviour; this consideration allows the application of spatial sharpening algorithms of thermal data, by means of a combination of high spatial resolution data in VIS/NIR range with high temporal acquisition on TIR. In this paper, a sharpening algorithm was applied using the thermal bands of MODIS (MOderate resolution Imaging Spectroradiometer) and vegetation indices derived by ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor; the choice of this sensors is justified by the simultaneous acquisition time. The results of this sharpening process was firstly compared against LST estimation (at the same spatial resolution) by means of the ASTER simultaneous data; then the derived high spatial resolution LST distribution was used in order to investigate the effect of the disaggregation on the outputs of surface energy balance models. The above described application was performed on a Sicilian study area.

  17. Spatially-controlled complex molecules and their applications

    E-print Network

    Chang, Yuan-Pin; Trippel, Sebastian; Küpper, Jochen

    2015-01-01

    The understanding of molecular structure and function is at the very heart of the chemical and molecular sciences. Experiments that allow for the creation of structurally pure samples and the investigation of their molecular dynamics and chemical function have developed tremendeously over the last few decades, although "there's plenty of room at the bottom" for better control as well as further applications. Here, we describe the use of inhomogeneous electric fields for the manipulation of neutral molecules in the gas-phase, \\ie, for the separation of complex molecules according to size, structural isomer, and quantum state. Current applications of these controlled samples are summarized and interesting future applications discussed.

  18. Tract-Based Spatial Statistics: Application to Mild Cognitive Impairment

    PubMed Central

    Wai, Yau-Yau; Hsu, Wen-Chuin; Fung, Hon-Chung; Lee, Jiann-Der; Chan, Hsiao-Lung; Tsai, Ming-Lun; Lin, Yu-Chun; Wu, Yih-Ru; Ying, Leslie; Wang, Jiun-Jie

    2014-01-01

    Rationale and Objectives. The primary objective of the current investigation was to characterize white matter integrity in different subtypes of mild cognitive impairment (MCI) using tract-based spatial statistics of diffusion tensor imaging. Materials and Methods. The study participants were divided into 4 groups of 30 subjects each as follows: cognitively healthy controls, amnestic MCI, dysexecutive MCI, and Alzheimer's disease (AD). All subjects underwent a comprehensive neuropsychological assessment, apolipoprotein E genotyping, and 3-tesla MRI. The diffusion tensor was reconstructed and then analyzed using tract-based spatial statistics. The changes in brain white matter tracts were also examined according to the apolipoprotein E ?4 status. Results. Compared with controls, amnestic MCI patients showed significant differences in the cerebral white matter, where changes were consistently detectable in the frontal and parietal lobes. We found a moderate impact of the apolipoprotein E ?4 status on the extent of white matter disruption in the amnestic MCI group. Patients with AD exhibited similar but more extensive alterations, while no significant changes were observed in dysexecutive MCI patients. Conclusion. The results from this study indicate that amnestic MCI is the most likely precursor to AD as both conditions share significant white matter damage. By contrast, dysexecutive MCI seems to be characterized by a distinct pathogenesis. PMID:24900978

  19. Yield response of potato to spatially patterned nitrogen application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The difference between experimental results and their application at the farm level is highlighted by the ever-present research issue of nitrogen fertilizer. Although crop response to nitrogen fertilizer has long been studied, inappropriate experimental designs led to the inadequate accounting of s...

  20. Spatial Optimization of Fertilizer Application by Centrifugal Spreading

    Microsoft Academic Search

    T. Virin; J. Koko; E. Piron; P. Martinet; M. Berducat; Blaise Pascal

    We study an approach for the optimization of spreading performed by centrifugal spreaders in order to minimize environmental effects due to application errors. Faced with a large scale problem, we divide the domain of study into subdomains so that each tramline is individually dealt with. In order to take into account the mechanical limits of the device, some inequality constraints

  1. In vivo application of short-lag spatial coherence and harmonic spatial coherence imaging in fetal ultrasound.

    PubMed

    Kakkad, Vaibhav; Dahl, Jeremy; Ellestad, Sarah; Trahey, Gregg

    2015-04-01

    Fetal scanning is one of the most common applications of ultrasound imaging and serves as a source of vital information about maternal and fetal health. Visualization of clinically relevant structures, however, can be severely compromised in difficult-to-image patients due to poor resolution and the presence of high levels of acoustical noise or clutter. We have developed novel coherence-based beamforming methods called Short-Lag Spatial Coherence (SLSC) imaging and Harmonic Spatial Coherence imaging (HSCI), and applied them to suppress the effects of clutter in fetal imaging. This method is used to create images of the spatial coherence of the backscattered ultrasound as opposed to images of echo magnitude. We present the results of a patient study to assess the benefits of coherence-based beamforming in the context of first trimester fetal exams. Matched fundamental B-mode, SLSC, harmonic B-mode, and HSCI images were generated using raw radio frequency data collected on 11 volunteers in the first trimester of pregnancy. The images were compared for qualitative differences in image texture and target conspicuity as well as using quantitative imaging metrics such as signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast. SLSC and HSCI showed statistically significant improvements across all imaging metrics compared with B-mode and harmonic B-mode, respectively. These improvements were greatest for poor quality B-mode images where contrast of anechoic targets was improved from 15 dB in fundamental B-mode to 27 dB in SLSC and 17 dB in harmonic B-mode to 30 dB in HSCI. CNR improved from 1.4 to 2.5 in the fundamental images and 1.4 to 3.1 in the harmonic case. These results exhibit the potential of coherence-based beamforming to improve image quality and target detectability, especially in high noise environments. PMID:25116292

  2. Integrating GIS and GPS into a spatially-variable-rate herbicide application system

    Microsoft Academic Search

    Khalid Ali Al-Gaadi

    1998-01-01

    A spatially variable rate herbicide application system was developed and a site-specific evaluation of its field performance and accuracy was conducted. The system was capable of automatically changing on-the-go the application rate of active ingredients (AI) to meet the requirements of current sprayer field location. A 4.2 ha field was sampled on an 18.3 m grid for soil texture and

  3. Spatially adaptive statistical modeling of wavelet image coefficients and its application to denoising

    Microsoft Academic Search

    M. Kivanc Mihcak; Igor Kozintsev; Kannan Ramchandran

    1999-01-01

    This paper deals with the application to denoising of a very simple but effective “local” spatially adaptive statistical model for the wavelet image representation that was previously introduced successfully in a compression context. Motivated by the intimate connection between compression and denoising, this paper explores the significant role of the underlying statistical wavelet image model. The model used here, a

  4. Design of a wideband antenna package with a compact spatial notch filter for wireless applications

    Microsoft Academic Search

    Judo Yeo; R. Mittra

    2002-01-01

    This paper describes a compact package, comprising a wideband antenna with a compact spatial notch filter, useful for RF applications requiring a high rate of data transfer. The use of fractal concepts helps to reduce the package to almost half the normal size, and to realize a much sharper band-stop than would be possible with a conventional filter. The antenna

  5. An Open GeoSpatial Standards-Enabled Google Earth Application to Support Crisis Management

    E-print Network

    Klippel, Alexander

    An Open GeoSpatial Standards-Enabled Google Earth Application to Support Crisis Management Scott-863-7943 Email: @psu.edu ABSTRACT Google Earth (GE) and related open geospatial technologies have changed both the accessibility of and audience for geospatial information dramatically

  6. Parallelized genetic optimization of spatial light modulator addressing for diffractive applications.

    PubMed

    Haist, Tobias; Lingel, Christian; Adler, Rodolfo; Osten, Wolfgang

    2014-03-01

    We describe a new technique for optimizing the addressing of spatial light modulators in dynamic holographic applications. The method utilizes 200 times parallelization using imaging of subholograms in combination with genetic optimization. Compared to a fixed linear addressing curve for all different gratings, the diffraction efficiency can be improved by up to 25% for a Holoeye Pluto LCoS modulator. PMID:24663371

  7. A Model Of Spatial Sorting In Animal Groups, With An Application To Honeybee

    E-print Network

    Sydney, University of

    A Model Of Spatial Sorting In Animal Groups, With An Application To Honeybee Swarm Movement A in these rules. In particular, the phenomenon of honeybee swarms migrating to a new nesting site is examined honeybees (Apis mellifera) and schools of migrating fishes (such as herring (Clupea harengus)). Further

  8. Learning Spatial-Temporal Varying Graphs with Applications to Climate Data Analysis

    E-print Network

    Carbonell, Jaime

    for the data drawn from a multivariate Gaussian distribu- tion. However, climatological data often turn out is that meteorological or climatological data often turn out to be non-Gaussian, e.g. precipitation, cloud coverLearning Spatial-Temporal Varying Graphs with Applications to Climate Data Analysis Xi Chen1

  9. Randomness in Computing and Simulations for Spherical and Spatial Geoscience Applications

    NASA Astrophysics Data System (ADS)

    Blais, J. A.

    2013-12-01

    Mathematical randomness has long been studied and in computing, different simulation approaches have been investigated and implemented in all kinds of stochastic computations. Following a brief overview of true (or physical), pseudo, chaotic and quasi-random number generation, some equi-distributed and low discrepancy sequences will be discussed in view of their well-known applications in Monte Carlo simulations. For spherical and spatial computations and simulations, a number of statistical and related considerations are important for geoscience applications. In particular, nonlinear domain and other transformations generally complicate the stochastic simulations and their inferences. Various sample applications will illustrate the complexities with suggested methodologies and some practical recommendations.

  10. Simulation of spatially evolving turbulence and the applicability of Taylor's hypothesis in compressible flow

    NASA Technical Reports Server (NTRS)

    Lee, Sangsan; Lele, Sanjiva K.; Moin, Parviz

    1992-01-01

    For the numerical simulation of inhomogeneous turbulent flows, a method is developed for generating stochastic inflow boundary conditions with a prescribed power spectrum. Turbulence statistics from spatial simulations using this method with a low fluctuation Mach number are in excellent agreement with the experimental data, which validates the procedure. Turbulence statistics from spatial simulations are also compared to those from temporal simulations using Taylor's hypothesis. Statistics such as turbulence intensity, vorticity, and velocity derivative skewness compare favorably with the temporal simulation. However, the statistics of dilatation show a significant departure from those obtained in the temporal simulation. To directly check the applicability of Taylor's hypothesis, space-time correlations of fluctuations in velocity, vorticity, and dilatation are investigated. Convection velocities based on vorticity and velocity fluctuations are computed as functions of the spatial and temporal separations. The profile of the space-time correlation of dilatation fluctuations is explained via a wave propagation model.

  11. Transmission Phase Holography: Spatial-Mode Filter Design for Quantum Information Applications

    NASA Astrophysics Data System (ADS)

    Hillmer, Rachel; Barreiro, Julio; Kwiat, Paul

    2007-03-01

    Photon spatial modes offer access to promising new applications in quantum information because they provide a higher-dimensional basis set than the usual two-dimensional one associated with polarization. Downconversion experiments have demonstrated spatial-mode entanglement [1], and even hyperentanglement in polarization and spatial mode [2]. However optical elements currently lack the refinement necessary to perform efficient, high-fidelity operations using spatial modes. Holographic filters for Laguerre-Gaussian and Hermite-Gaussian laser modes can act as modes converters, and have long been studied (under the terms ``modans'' and ``kinoforms'') for use in electrical engineering applications [3,4]. Her we present analytical refinements and optimizations of these techniques, with predicted mode fidelities over 95% and diffraction efficiencies up to 98%. Results of our experimental implementions of these solutions are presented. [1] Walborn, S.P, et al, ``Entanglement and conservation of orbital angular momentum in spontaneous parametric down-conversion,'' Phys. Rev. A 69, 023811 (2004); [2] Barreiro, J.T. et al, ``Generation of Hyperentangled Photon Pairs,'' Phys. Rev. Lett. 95, 260501 (2005); [3] Soifer, V.A., ``Methods of Computer Design of Diffractive Optical Elements,'' John Wiley & Sons, Inc., 2002; [4] Golub, M. and Soifer, V., ``Laser Beam Mode Selection by Computer Generated Holograms,'' CRC Press, Inc., 1994.

  12. Jackson State University's Center for Spatial Data Research and Applications: New facilities and new paradigms

    NASA Technical Reports Server (NTRS)

    Davis, Bruce E.; Elliot, Gregory

    1989-01-01

    Jackson State University recently established the Center for Spatial Data Research and Applications, a Geographical Information System (GIS) and remote sensing laboratory. Taking advantage of new technologies and new directions in the spatial (geographic) sciences, JSU is building a Center of Excellence in Spatial Data Management. New opportunities for research, applications, and employment are emerging. GIS requires fundamental shifts and new demands in traditional computer science and geographic training. The Center is not merely another computer lab but is one setting the pace in a new applied frontier. GIS and its associated technologies are discussed. The Center's facilities are described. An ARC/INFO GIS runs on a Vax mainframe, with numerous workstations. Image processing packages include ELAS, LIPS, VICAR, and ERDAS. A host of hardware and software peripheral are used in support. Numerous projects are underway, such as the construction of a Gulf of Mexico environmental data base, development of AI in image processing, a land use dynamics study of metropolitan Jackson, and others. A new academic interdisciplinary program in Spatial Data Management is under development, combining courses in Geography and Computer Science. The broad range of JSU's GIS and remote sensing activities is addressed. The impacts on changing paradigms in the university and in the professional world conclude the discussion.

  13. High-Q polymer resonators with spatially controlled photo-functionalization for biosensing applications

    NASA Astrophysics Data System (ADS)

    Beck, Torsten; Mai, Martin; Grossmann, Tobias; Wienhold, Tobias; Hauser, Mario; Mappes, Timo; Kalt, Heinz

    2013-03-01

    We demonstrate the applicability of polymeric whispering gallery mode resonators fabricated on silicon as biosensors. Optical measurements on the passive resonators in the visible spectral range yield Q-factors as high as 1.3×107. Local, covalent surface functionalization, is achieved by spatially controlled UV-exposure of a derivative of the photoreactive crosslinker benzophenone. Protein detection is shown using the specific binding of the biotin-streptavidin system.

  14. CADASTRAL APPLICATION OF SATELLITE IMAGES WITH HIGH SPATIAL RESOLUTION IN EASTER ISLAND (CHILE)

    Microsoft Academic Search

    V. Herrera; J. Borcosque

    The purpose of this project is to demonstrate the potentiality of satellite images with high spatial resolution (QuickBridII) and GPS system for cadastral applications in a zone so particular in landuse administration like Rapa Nui or Easter Island, located in the middle of the Pacific Ocean, lat 27º 07' long 109º 22' in front to the Chilean coast. Additionally, the

  15. Fiber-based, spatially and temporally shaped picosecond UV laser for advanced RF gun applications

    Microsoft Academic Search

    M. Y. Shverdin; S. G. Anderson; S. M. Betts; D. J. Gibson; F. V. Hartemann; J. E. Hernandez; M. Johnson; I. Jovanovic; D. P. McNabb; M. Messerly; J. Pruet; A. M. Tremaine; C. W. Siders; C. P. J. Barty

    2007-01-01

    The fiber-based, spatially and temporally shaped, picosecond UV laser system described here has been specifically designed for advanced rf gun applications, with a special emphasis on the production of high-brightness electron beams for free-electron lasers and Compton scattering light sources. The laser pulse can be shaped to a flat-top in both space and time with a duration of 10 ps

  16. Displaying R spatial statistics on Google dynamic maps with web applications created by Rwui

    PubMed Central

    2012-01-01

    Background The R project includes a large variety of packages designed for spatial statistics. Google dynamic maps provide web based access to global maps and satellite imagery. We describe a method for displaying directly the spatial output from an R script on to a Google dynamic map. Methods This is achieved by creating a Java based web application which runs the R script and then displays the results on the dynamic map. In order to make this method easy to implement by those unfamiliar with programming Java based web applications, we have added the method to the options available in the R Web User Interface (Rwui) application. Rwui is an established web application for creating web applications for running R scripts. A feature of Rwui is that all the code for the web application being created is generated automatically so that someone with no knowledge of web programming can make a fully functional web application for running an R script in a matter of minutes. Results Rwui can now be used to create web applications that will display the results from an R script on a Google dynamic map. Results may be displayed as discrete markers and/or as continuous overlays. In addition, users of the web application may select regions of interest on the dynamic map with mouse clicks and the coordinates of the region of interest will automatically be made available for use by the R script. Conclusions This method of displaying R output on dynamic maps is designed to be of use in a number of areas. Firstly it allows statisticians, working in R and developing methods in spatial statistics, to easily visualise the results of applying their methods to real world data. Secondly, it allows researchers who are using R to study health geographics data, to display their results directly onto dynamic maps. Thirdly, by creating a web application for running an R script, a statistician can enable users entirely unfamiliar with R to run R coded statistical analyses of health geographics data. Fourthly, we envisage an educational role for such applications. PMID:22998945

  17. Comparison of alternative spatial resolutions in the application of a spatially distributed biogeochemical model over complex terrain

    Microsoft Academic Search

    David P. Turner; Rusty Dodson; Danny Marks

    1996-01-01

    Spatially distributed biogeochemical models may be applied over grids at a range of spatial resolutions, however, evaluation of potential errors and loss of information at relatively coarse resolutions is rare. In this study, a georeferenced database at the 1-km spatial resolution was developed to initialize and drive a process-based model (Forest-BGC) of water and carbon balance over a gridded 54976

  18. The market value of cultural heritage in urban areas: an application of spatial hedonic pricing

    NASA Astrophysics Data System (ADS)

    Lazrak, Faroek; Nijkamp, Peter; Rietveld, Piet; Rouwendal, Jan

    2014-01-01

    The current literature often values intangible goods like cultural heritage by applying stated preference methods. In recent years, however, the increasing availability of large databases on real estate transactions and listed prices has opened up new research possibilities and has reduced various existing barriers to applications of conventional (spatial) hedonic analysis to the real estate market. The present paper provides one of the first applications using a spatial autoregressive model to investigate the impact of cultural heritage—in particular, listed buildings and historic-cultural sites (or historic landmarks)—on the value of real estate in cities. In addition, this paper suggests a novel way of specifying the spatial weight matrix—only prices of sold houses influence current price—in identifying the spatial dependency effects between sold properties. The empirical application in the present study concerns the Dutch urban area of Zaanstad, a historic area for which over a long period of more than 20 years detailed information on individual dwellings, and their market prices are available in a GIS context. In this paper, the effect of cultural heritage is analysed in three complementary ways. First, we measure the effect of a listed building on its market price in the relevant area concerned. Secondly, we investigate the value that listed heritage has on nearby property. And finally, we estimate the effect of historic-cultural sites on real estate prices. We find that, to purchase a listed building, buyers are willing to pay an additional 26.9 %, while surrounding houses are worth an extra 0.28 % for each additional listed building within a 50-m radius. Houses sold within a conservation area appear to gain a premium of 26.4 % which confirms the existence of a `historic ensemble' effect.

  19. A spatially filtered multilevel model to account for spatial dependency: application to self-rated health status in South Korea

    PubMed Central

    2014-01-01

    Background This study aims to suggest an approach that integrates multilevel models and eigenvector spatial filtering methods and apply it to a case study of self-rated health status in South Korea. In many previous health-related studies, multilevel models and single-level spatial regression are used separately. However, the two methods should be used in conjunction because the objectives of both approaches are important in health-related analyses. The multilevel model enables the simultaneous analysis of both individual and neighborhood factors influencing health outcomes. However, the results of conventional multilevel models are potentially misleading when spatial dependency across neighborhoods exists. Spatial dependency in health-related data indicates that health outcomes in nearby neighborhoods are more similar to each other than those in distant neighborhoods. Spatial regression models can address this problem by modeling spatial dependency. This study explores the possibility of integrating a multilevel model and eigenvector spatial filtering, an advanced spatial regression for addressing spatial dependency in datasets. Methods In this spatially filtered multilevel model, eigenvectors function as additional explanatory variables accounting for unexplained spatial dependency within the neighborhood-level error. The specification addresses the inability of conventional multilevel models to account for spatial dependency, and thereby, generates more robust outputs. Results The findings show that sex, employment status, monthly household income, and perceived levels of stress are significantly associated with self-rated health status. Residents living in neighborhoods with low deprivation and a high doctor-to-resident ratio tend to report higher health status. The spatially filtered multilevel model provides unbiased estimations and improves the explanatory power of the model compared to conventional multilevel models although there are no changes in the signs of parameters and the significance levels between the two models in this case study. Conclusions The integrated approach proposed in this paper is a useful tool for understanding the geographical distribution of self-rated health status within a multilevel framework. In future research, it would be useful to apply the spatially filtered multilevel model to other datasets in order to clarify the differences between the two models. It is anticipated that this integrated method will also out-perform conventional models when it is used in other contexts. PMID:24571639

  20. Binomial tau-leap spatial stochastic simulation algorithm for applications in chemical kinetics

    NASA Astrophysics Data System (ADS)

    Marquez-Lago, Tatiana T.; Burrage, Kevin

    2007-09-01

    In cell biology, cell signaling pathway problems are often tackled with deterministic temporal models, well mixed stochastic simulators, and/or hybrid methods. But, in fact, three dimensional stochastic spatial modeling of reactions happening inside the cell is needed in order to fully understand these cell signaling pathways. This is because noise effects, low molecular concentrations, and spatial heterogeneity can all affect the cellular dynamics. However, there are ways in which important effects can be accounted without going to the extent of using highly resolved spatial simulators (such as single-particle software), hence reducing the overall computation time significantly. We present a new coarse grained modified version of the next subvolume method that allows the user to consider both diffusion and reaction events in relatively long simulation time spans as compared with the original method and other commonly used fully stochastic computational methods. Benchmarking of the simulation algorithm was performed through comparison with the next subvolume method and well mixed models (MATLAB), as well as stochastic particle reaction and transport simulations (CHEMCELL, Sandia National Laboratories). Additionally, we construct a model based on a set of chemical reactions in the epidermal growth factor receptor pathway. For this particular application and a bistable chemical system example, we analyze and outline the advantages of our presented binomial ?-leap spatial stochastic simulation algorithm, in terms of efficiency and accuracy, in scenarios of both molecular homogeneity and heterogeneity.

  1. Spatial variability of soil potassium in sugarcane areas subjected to the application of vinasse.

    PubMed

    De Carvalho, Laércio A; Meurer, Ismael; Da Silva Junior, Carlos A; Santos, Cristiane F B; Libardi, Paulo L

    2014-12-01

    When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al) and potential acidity (H + Al). The data have been submitted to analysis of descriptive statistics and the K attribute was subjected to geostatistical analysis. The coefficient of variation indicated medium and high variability of K for the three soils. The results showed that the spatial dependence of K increased in depth to FRce and decreased to PHlv, indicating that the attribute could have followed the pattern of distribution of clay in depth. The investigation of the spatial variability of K on the surface and subsurface soils provided the definition of management zones with different levels of fertility, which can be organized into sub-areas for a more efficient management of the resources and the environment. PMID:25590735

  2. Spatial conductivity mapping of carbon nanotube composite thin films by electrical impedance tomography for sensing applications

    NASA Astrophysics Data System (ADS)

    Hou, Tsung-Chin; Loh, Kenneth J.; Lynch, Jerome P.

    2007-08-01

    This paper describes the application of electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by a layer-by-layer (LbL) technique and mounted with electrodes along their boundaries. The response of the thin films to various stimuli is investigated by relying on electric current excitation and corresponding boundary potential measurements. The spatial conductivity variations are reconstructed based on a mathematical model for the EIT technique. Here, the ability of the EIT method to provide two-dimensional mapping of the conductivity of CNT thin films is validated by (1) electrically imaging intentional structural defects in the thin films and (2) mapping the film's response to various pH environments. The ability to spatially image the conductivity of CNT thin films holds many promises for developing multifunctional CNT-based sensing skins.

  3. Transformative Relation of Kinematical Descriptive Quantities Defined by Different Spatial Referential Frame, Its Property and Application

    NASA Astrophysics Data System (ADS)

    Luo, Ji

    2012-08-01

    Quantitative transformations between corresponding kinetic quantities defined by any two spatial referential frames, whose relative kinematics relations (purely rotational and translational movement) are known, are presented based on necessarily descriptive definitions of the fundamental concepts (instant, time, spatial referential frame that distinguishes from Maths. Coordination, physical point) had being clarified by directly empirical observation with artificially descriptive purpose. Inductive investigation of the transformation reveals that all physical quantities such as charge, temperature, time, volume, length, temporal rate of the quantities and relations like temporal relation between signal source and observer as such are independent to spatial frames transformation except above kinematical quantities transformations, kinematics related dynamics such as Newton ’ s second law existing only in inertial frames and exchange of kinetic energy of mass being valid only in a selected inertial frame. From above bas is, we demonstrate a series of inferences and applications such as phase velocity of light being direct respect to medium (including vacuum) rather than to the frame, using spatial referential frame to describe any measurable field (electric field, magnetic field, gravitational field) and the field ’ s variation; and have tables to contrast and evaluate all aspects of those hypotheses related with spacetime such as distorted spacetime around massive stellar, four dimension spacetime, gravitational time dilation and non - Euclid geometry with new one. The demonstration strongly suggests all the hypotheses are invalid in capable tested concepts ’ meaning and relations. The conventional work on frame transformation and its property, hypothesized by Voigt, Heaviside, Lorentz, Poincare and Einstein a century ago with some mathematical speculation lacking rigorous definition of the fundamental concepts such as instant, time, spatial reference, straight line, plane area, merely good in building up patchwork to do self p referred explanation by making up derivative concepts or accumulating new hypothesis, has disturbed people to describe the physical nature by setting up the sound basis of concept and relations with capable tested method, it’s time to be replaced by empirically effective alternative.

  4. Comparison of alternative spatial resolutions in the application of a spatially distributed biogeochemical model over complex terrain

    USGS Publications Warehouse

    Turner, D.P.; Dodson, R.; Marks, D.

    1996-01-01

    Spatially distributed biogeochemical models may be applied over grids at a range of spatial resolutions, however, evaluation of potential errors and loss of information at relatively coarse resolutions is rare. In this study, a georeferenced database at the 1-km spatial resolution was developed to initialize and drive a process-based model (Forest-BGC) of water and carbon balance over a gridded 54976 km2 area covering two river basins in mountainous western Oregon. Corresponding data sets were also prepared at 10-km and 50-km spatial resolutions using commonly employed aggregation schemes. Estimates were made at each grid cell for climate variables including daily solar radiation, air temperature, humidity, and precipitation. The topographic structure, water holding capacity, vegetation type and leaf area index were likewise estimated for initial conditions. The daily time series for the climatic drivers was developed from interpolations of meteorological station data for the water year 1990 (1 October 1989-30 September 1990). Model outputs at the 1-km resolution showed good agreement with observed patterns in runoff and productivity. The ranges for model inputs at the 10-km and 50-km resolutions tended to contract because of the smoothed topography. Estimates for mean evapotranspiration and runoff were relatively insensitive to changing the spatial resolution of the grid whereas estimates of mean annual net primary production varied by 11%. The designation of a vegetation type and leaf area at the 50-km resolution often subsumed significant heterogeneity in vegetation, and this factor accounted for much of the difference in the mean values for the carbon flux variables. Although area wide means for model outputs were generally similar across resolutions, difference maps often revealed large areas of disagreement. Relatively high spatial resolution analyses of biogeochemical cycling are desirable from several perspectives and may be particularly important in the study of the potential impacts of climate change.

  5. A hierarchical spatial model of avian abundance with application to Cerulean Warblers

    USGS Publications Warehouse

    Thogmartin, W.E.; Sauer, J.R.; Knutson, M.G.

    2004-01-01

    Surveys collecting count data are the primary means by which abundance is indexed for birds. These counts are confounded, however, by nuisance effects including observer effects and spatial correlation between counts. Current methods poorly accommodate both observer and spatial effects because modeling these spatially autocorrelated counts within a hierarchical framework is not practical using standard statistical approaches. We propose a Bayesian approach to this problem and provide as an example of its implementation a spatial model of predicted abundance for the Cerulean Warbler (Dendroica cerulea) in the Prairie-Hardwood Transition of the upper midwestern United States. We used an overdispersed Poisson regression with fixed and random effects, fitted by Markov chain Monte Carlo methods. We used 21 years of North American Breeding Bird Survey counts as the response in a loglinear function of explanatory variables describing habitat, spatial relatedness, year effects, and observer effects. The model included a conditional autoregressive term representing potential correlation between adjacent route counts. Categories of explanatory habitat variables in the model included land cover composition and configuration, climate, terrain heterogeneity, and human influence. The inherent hierarchy in the model was from counts occurring, in part, as a function of observers within survey routes within years. We found that the percentage of forested wetlands, an index of wetness potential, and an interaction between mean annual precipitation and deciduous forest patch size best described Cerulean Warbler abundance. Based on a map of relative abundance derived from the posterior parameter estimates, we estimated that only 15% of the species' population occurred on federal land, necessitating active engagement of public landowners and state agencies in the conservation of the breeding habitat for this species. Models of this type can be applied to any data in which the response is counts, such as animal counts, activity (e.g.,nest) counts, or species richness. The most noteworthy practical application of this spatial modeling approach is the ability to map relative species abundance. The functional relationships that we elucidated for the Cerulean Warbler provide a basis for the development of management programs and may serve to focus management and monitoring on areas and habitat variables important to Cerulean Warblers.

  6. Lack of spatial and behavioral responses to immunocontraception application in African elephants (Loxodonta africana).

    PubMed

    Delsink, Audrey K; Kirkpatrick, Jay; van Altena, J J; Bertschinger, Henk J; Ferreira, Sam M; Slotow, Robert

    2013-12-01

    Opinions are divided as to whether human intervention to control elephant (Loxodonta africana) population growth is desirable, partly because of elephant welfare concerns. Female contraception through immunization with porcine zona pellucida (PZP) proteins is viable. The effects of sustained use and application of the PZP vaccine on elephant behavioral and spatial responses were examined by evaluating herd ranging, fission-fusion dynamics, association patterns, and reproductive and sexual behaviors. Minimal change was anticipated as a result of long calf dependence on and association with cows, a reduced but not indefinite 0% growth rate and the known mechanism of action of PZP vaccines, and minimal expected change in resource requirements necessitating behavioral or spatial use adaptations. Although behavioral effects identified in previous hormonal contraceptive trials were evident, it was demonstrated that immunocontraception caused no prolonged behavioral, social, or spatial changes over the 11-yr study period. Individually identified elephants were monitored from 1999 to 2011. Minimal, short-term social disruption, with temporary changes to the herds' core ranges, was observed during the annual treatment events, particularly in the first three treatment years, when vaccinations were conducted exclusively from the ground. Thereafter, when vaccinations were conducted aerially, minor disruptions were confined to the morning of administration only. Despite sustained treatments resulting in demographic changes of fewer calves being born, treatments did not alter spatial range use, and no adverse interherd-intraherd relations were observed. Similarly, resource requirements did not change as calving still occurred, although in fewer numbers. It was concluded that PZP immunocontraception has no detectable behavioral or social consequences in elephants over the course of 11 yr, providing a convincing argument for the use of sustained immunocontraception in the medium to long term as an important tool for elephant management. Behavioral consequences of alternative management approaches should all receive similar scrutiny to enable managers to make informed decisions when weighing management interventions. PMID:24437086

  7. Skew-elliptical spatial random effect modeling for areal data with application to mapping health utilization rates.

    PubMed

    Nathoo, Farouk S; Ghosh, Pulak

    2013-01-30

    Mixed models incorporating spatially correlated random effects are often used for the analysis of areal data. In this setting, spatial smoothing is introduced at the second stage of a hierarchical framework, and this smoothing is often based on a latent Gaussian Markov random field. The Markov random field provides a computationally convenient framework for modeling spatial dependence; however, the Gaussian assumption underlying commonly used models can be overly restrictive in some applications. This can be a problem in the presence of outliers or discontinuities in the underlying spatial surface, and in such settings, models based on non-Gaussian spatial random effects are useful. Motivated by a study examining geographic variation in the treatment of acute coronary syndrome, we develop a robust model for smoothing small-area health service utilization rates. The model incorporates non-Gaussian spatial random effects, and we develop a formulation for skew-elliptical areal spatial models. We generalize the Gaussian conditional autoregressive model to the non-Gaussian case, allowing for asymmetric skew-elliptical marginal distributions having flexible tail behavior. The resulting new models are flexible, computationally manageable, and can be implemented in the standard Bayesian software WinBUGS. We demonstrate performance of the proposed methods and comparisons with other commonly used Gaussian and non-Gaussian spatial prior formulations through simulation and analysis in our motivating application, mapping rates of revascularization for patients diagnosed with acute coronary syndrome in Quebec, Canada. PMID:22815268

  8. Active crop canopy sensor optimal spatial scale for in-season variable-rate nitrogen application in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Active crop canopy reflectance sensors have shown to be an efficient method for assessing spatially-variable crop nitrogen (N) need and controlling remedial in-season N applications in wheat. Recently, these sensors have been studied for N application in corn. This study will be conducted during the...

  9. Exploring population spatial concentrations in Northern Ireland by community background and other characteristics: an application of geographically weighted spatial statistics

    Microsoft Academic Search

    Christopher D. Lloyd

    2010-01-01

    Information on how populations are spatially concentrated by different characteristics is a key means of guiding government policies in a variety of contexts, in addition to being of substantial academic interest. In particular, to reduce inequalities between groups, it is necessary to understand the characteristics of these groups in terms of their composition and their geographical structure. This article explores

  10. Making digital phantoms with spectral and spatial light modulators for quantitative applications of hyperspectral optical medical imaging devices

    NASA Astrophysics Data System (ADS)

    Chon, Bonghwan; Tokumasu, Fuyuki; Lee, Ji Youn; Allen, David W.; Rice, Joseph P.; Hwang, Jeeseong

    2015-03-01

    We present a procedure to generate digital phantoms with a hyperspectral image projector (HIP) consisting of two liquid crystal on silicon (LCoS) spatial light modulators (SLMs). The digital phantoms are 3D image data cubes of the spatial distribution of spectrally resolved abundances of intracellular light-absorbing oxy-hemoglobin molecules in single erythrocytes. Spectrally and spatially resolved image data indistinguishable from the real scene may be used as standards to calibrate image sensors and validate image analysis algorithms for their measurement quality, performance consistency, and inter-laboratory comparisons for quantitative biomedical imaging applications.

  11. Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas.

    PubMed

    Hill, K W; Bitter, M; Delgado-Aparacio, L; Pablant, N A; Beiersdorfer, P; Schneider, M; Widmann, K; Sanchez del Rio, M; Zhang, L

    2012-10-01

    High resolution (???? ? 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-?m (55)Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10(-8)-10(-6) times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented. PMID:23126946

  12. Fiber-Based, Spatially and Temporally Shaped Picosecond UV Laser for Advanced RF Gun Applications

    SciTech Connect

    Shverdin, M Y; Anderson, S G; Betts, S M; Gibson, D J; Hartemann, F V; Hernandez, J E; Johnson, M; Jovanovic, I; Messerly, M; Pruet, J; Tremaine, A M; McNabb, D P; Siders, C W; Barty, C J

    2007-06-08

    The fiber-based, spatially and temporally shaped, picosecond UV laser system described here has been specifically designed for advanced rf gun applications, with a special emphasis on the production of high-brightness electron beams for free-electron lasers and Compton scattering light sources. The laser pulse can be shaped to a flat-top in both space and time with a duration of 10 ps at full width of half-maximum (FWHM) and rise and fall times under 1 ps. The expected pulse energy is 50 {micro}J at 261.75 nm and the spot size diameter of the beam at the photocathode is 2 mm. A fiber oscillator and amplifier system generates a chirped pump pulse at 1047 nm; stretching is achieved in a chirped fiber Bragg grating. A single multi-layer dielectric grating based compressor recompresses the input pulse to 250 fs FWHM and a two stage harmonic converter frequency quadruples the beam. Temporal shaping is achieved with a Michelson-based ultrafast pulse stacking device with nearly 100% throughput. Spatial shaping is achieved by truncating the beam at the 20% energy level with an iris and relay-imaging the resulting beam profile onto the photocathode. The integration of the system, as well as preliminary laser measurements will be presented.

  13. Using GIS to generate spatially balanced random survey designs for natural resource applications.

    PubMed

    Theobald, David M; Stevens, Don L; White, Denis; Urquhart, N Scott; Olsen, Anthony R; Norman, John B

    2007-07-01

    Sampling of a population is frequently required to understand trends and patterns in natural resource management because financial and time constraints preclude a complete census. A rigorous probability-based survey design specifies where to sample so that inferences from the sample apply to the entire population. Probability survey designs should be used in natural resource and environmental management situations because they provide the mathematical foundation for statistical inference. Development of long-term monitoring designs demand survey designs that achieve statistical rigor and are efficient but remain flexible to inevitable logistical or practical constraints during field data collection. Here we describe an approach to probability-based survey design, called the Reversed Randomized Quadrant-Recursive Raster, based on the concept of spatially balanced sampling and implemented in a geographic information system. This provides environmental managers a practical tool to generate flexible and efficient survey designs for natural resource applications. Factors commonly used to modify sampling intensity, such as categories, gradients, or accessibility, can be readily incorporated into the spatially balanced sample design. PMID:17546523

  14. Applications of spatially periodic field eddy current sensors for surface layer characterization in metallic alloys

    NASA Astrophysics Data System (ADS)

    Zilberstein, Vladimir; Sheiretov, Yanko; Washabaugh, Andrew; Chen, Yonghua; Goldfine, Neil J.

    2001-04-01

    Spatially periodic field eddy current sensors such as the Meandering Winding Magnetometer (MWM) with Grid Methods provide a powerful capability to nondestructively characterize surface layers introduced during fabrication as well as those modified by service exposure. This is critical for process quality control and component condition assessment. Conformable MWM sensors provide absolute property measurements (conductivity, permeability) and dimensional data (coating thickness, proximity) over flat and curved surfaces with minimal calibration requirements. Using a three-layer (substrate, coating, air) model and an inversion algorithm, a new measurement module has been developed to estimate the thickness of a process-affected zone and to provide a measure of property variations in this zone in real time. This paper presents results for two specific process quality control applications: (1) alpha case thickness measurements in a titanium alloy and (2) characterization of shot peening for aluminum alloys.

  15. Spatial light modulators and applications III; Proceedings of the Meeting, San Diego, CA, Aug. 7, 8, 1989

    NASA Technical Reports Server (NTRS)

    Efron, Uzi (editor)

    1990-01-01

    Recent advances in the technology and applications of spatial light modulators (SLMs) are discussed in review essays by leading experts. Topics addressed include materials for SLMs, SLM devices and device technology, applications to optical data processing, and applications to artificial neural networks. Particular attention is given to nonlinear optical polymers, liquid crystals, magnetooptic SLMs, multiple-quantum-well SLMs, deformable-mirror SLMs, three-dimensional optical memories, applications of photorefractive devices to optical computing, photonic neurocomputers and learning machines, holographic associative memories, SLMs as parallel memories for optoelectronic neural networks, and coherent-optics implementations of neural-network models.

  16. Spatial stochastic processes for yield and reliability management with applications to nano electronics 

    E-print Network

    Hwang, Jung Yoon

    2005-02-17

    This study uses the spatial features of defects on the wafers to examine the detection and control of process variation in semiconductor fabrication. It applies spatial stochastic process to semiconductor yield modeling ...

  17. EMCCD based luminescence imaging system for spatially resolved geo-chronometric and radiation dosimetric applications

    NASA Astrophysics Data System (ADS)

    Chauhan, N.; Adhyaru, P.; Vaghela, H.; Singhvi, A. K.

    2014-11-01

    We report the development of an Electron Multiplier Charge Coupled Device (EMCCD) based luminescence dating system. The system enables position sensitive measurements of luminescence for the estimation of spatially resolved distribution of equivalent dose for complex geological samples. The system includes: 1) a sample stimulation unit (with both thermal and optical stimulations), 2) an optics unit that comprises imaging optics and, 3) a data acquisition and processing unit. The system works in a LabVIEW environment with a graphical user interface (GUI). User specified stimulation protocols enable thermal and optical stimulation in any desired combination. The optics unit images the luminescence on to a EMCCD (512 × 512 pixels, each of 16?m × 16?m size) and maintains a unit magnification. This unit has flexible focusing and a filter housing that enables change of filters combinations without disturbing the setup. Time integrated EMCCD images of luminescence from the sample are acquired as a function of programmable dwell time and these images are processed using indigenously developed MATLAB based programs. Additionally, the programs align the acquired images using a set of control points (identifier features on the images) to a single pixel accuracy. The dose evaluation is based on integrated intensity from selected pixels followed by generation of a growth curve giving luminescence as a function of applied beta doses. Development of this EMCCD camera based luminescence system will enable in-situ luminescence measurements of the samples, without the requirement of separating mineral grains from their matrix. It will also allow age estimation of samples such as lithic artifacts/structures via dating of their surfaces, fusion crust of meteorites, pedogenic carbonates, etc and will additionally open up possibilities of application like testing spatial uniformity of doping in artificial luminescence phosphors, dating/dosimetry of inclusions etc.

  18. DOTAGWA: A CASE STUDY IN WEB-BASED ARCHITECTURES FOR CONNECTING SURFACE WATER MODELS TO SPATIALLY ENABLED WEB APPLICATIONS

    EPA Science Inventory

    The Automated Geospatial Watershed Assessment (AGWA) tool is a desktop application that uses widely available standardized spatial datasets to derive inputs for multi-scale hydrologic models (Miller et al., 2007). The required data sets include topography (DEM data), soils, clima...

  19. EVALUATING THE DYNAMIC AND SPATIAL ECONOMIC IMPACTS OF AN EARTHQUAKE: A CGE APPLICATION TO JAPAN

    Microsoft Academic Search

    Hiroyuki SHIBUSAWA; Yuzuru MIYATA

    2011-01-01

    We have developed a dynamic spatial computable general equilibrium model to investigate the regional economic impacts of an earthquake. In our spatial model, Japan is subdivided into 47 regions. All the regions are connected by transportation networks. Our model is of a decentralized economy with utility-maximizing consumers and value-maximizing firms in a dynamic context. The model embodies both the spatial

  20. Growth and Characterization of Chalcogenide Alloy Nanowires with Controlled Spatial Composition Variation for Optoelectronic Applications

    NASA Astrophysics Data System (ADS)

    Nichols, Patricia

    The energy band gap of a semiconductor material critically influences the operating wavelength of an optoelectronic device. Realization of any desired band gap, or even spatially graded band gaps, is important for applications such as lasers, light-emitting diodes (LEDs), solar cells, and detectors. Compared to thin films, nanowires offer greater flexibility for achieving a variety of alloy compositions. Furthermore, the nanowire geometry permits simultaneous incorporation of a wide range of compositions on a single substrate. Such controllable alloy composition variation can be realized either within an individual nanowire or between distinct nanowires across a substrate. This dissertation explores the control of spatial composition variation in ternary alloy nanowires. Nanowires were grown by the vapor-liquid-solid (VLS) mechanism using chemical vapor deposition (CVD). The gas-phase supersaturation was considered in order to optimize the deposition morphology. Composition and structure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD). Optical properties were investigated through photoluminescence (PL) measurements. The chalcogenides selected as alloy endpoints were lead sulfide (PbS), cadmium sulfide (CdS), and cadmium selenide (CdSe). Three growth modes of PbS were identified, which included contributions from spontaneously generated catalyst. The resulting wires were found capable of lasing with wavelengths over 4000 nm, representing the longest known wavelength from a sub-wavelength wire. For CdxPb1-xS nanowires, it was established that the cooling process significantly affects the alloy composition and structure. Quenching was critical to retain metastable alloys with x up to 0.14, representing a new composition in nanowire form. Alternatively, gradual cooling caused phase segregation, which created heterostructures with light emission in both the visible and mid-infrared regimes. The CdSSe alloy system was fully explored for spatial composition variation. CdSxSe1-x nanowires were grown with composition variation across the substrate. Subsequent contact printing preserved the designed composition gradient and led to the demonstration of a variable wavelength photodetector device. CdSSe axial heterostructure nanowires were also achieved. The growth process involved many variables, including a deliberate and controllable change in substrate temperature. As a result, both red and green light emission was detected from single nanowires.

  1. Spatial Preference Modelling for equitable infrastructure provision: an application of Sen's Capability Approach

    NASA Astrophysics Data System (ADS)

    Wismadi, Arif; Zuidgeest, Mark; Brussel, Mark; van Maarseveen, Martin

    2014-01-01

    To determine whether the inclusion of spatial neighbourhood comparison factors in Preference Modelling allows spatial decision support systems (SDSSs) to better address spatial equity, we introduce Spatial Preference Modelling (SPM). To evaluate the effectiveness of this model in addressing equity, various standardisation functions in both Non-Spatial Preference Modelling and SPM are compared. The evaluation involves applying the model to a resource location-allocation problem for transport infrastructure in the Special Province of Yogyakarta in Indonesia. We apply Amartya Sen's Capability Approach to define opportunity to mobility as a non-income indicator. Using the extended Moran's I interpretation for spatial equity, we evaluate the distribution output regarding, first, `the spatial distribution patterns of priority targeting for allocation' (SPT) and, second, `the effect of new distribution patterns after location-allocation' (ELA). The Moran's I index of the initial map and its comparison with six patterns for SPT as well as ELA consistently indicates that the SPM is more effective for addressing spatial equity. We conclude that the inclusion of spatial neighbourhood comparison factors in Preference Modelling improves the capability of SDSS to address spatial equity. This study thus proposes a new formal method for SDSS with specific attention on resource location-allocation to address spatial equity.

  2. Spatial Preference Modelling for equitable infrastructure provision: an application of Sen's Capability Approach

    NASA Astrophysics Data System (ADS)

    Wismadi, Arif; Zuidgeest, Mark; Brussel, Mark; van Maarseveen, Martin

    2013-04-01

    To determine whether the inclusion of spatial neighbourhood comparison factors in Preference Modelling allows spatial decision support systems (SDSSs) to better address spatial equity, we introduce Spatial Preference Modelling (SPM). To evaluate the effectiveness of this model in addressing equity, various standardisation functions in both Non-Spatial Preference Modelling and SPM are compared. The evaluation involves applying the model to a resource location-allocation problem for transport infrastructure in the Special Province of Yogyakarta in Indonesia. We apply Amartya Sen's Capability Approach to define opportunity to mobility as a non-income indicator. Using the extended Moran's I interpretation for spatial equity, we evaluate the distribution output regarding, first, `the spatial distribution patterns of priority targeting for allocation' (SPT) and, second, `the effect of new distribution patterns after location-allocation' (ELA). The Moran's I index of the initial map and its comparison with six patterns for SPT as well as ELA consistently indicates that the SPM is more effective for addressing spatial equity. We conclude that the inclusion of spatial neighbourhood comparison factors in Preference Modelling improves the capability of SDSS to address spatial equity. This study thus proposes a new formal method for SDSS with specific attention on resource location-allocation to address spatial equity.

  3. Classifying spatial patterns of brain activity with machine learning methods: application to lie detection.

    PubMed

    Davatzikos, C; Ruparel, K; Fan, Y; Shen, D G; Acharyya, M; Loughead, J W; Gur, R C; Langleben, D D

    2005-11-15

    Patterns of brain activity during deception have recently been characterized with fMRI on the multi-subject average group level. The clinical value of fMRI in lie detection will be determined by the ability to detect deception in individual subjects, rather than group averages. High-dimensional non-linear pattern classification methods applied to functional magnetic resonance (fMRI) images were used to discriminate between the spatial patterns of brain activity associated with lie and truth. In 22 participants performing a forced-choice deception task, 99% of the true and false responses were discriminated correctly. Predictive accuracy, assessed by cross-validation in participants not included in training, was 88%. The results demonstrate the potential of non-linear machine learning techniques in lie detection and other possible clinical applications of fMRI in individual subjects, and indicate that accurate clinical tests could be based on measurements of brain function with fMRI. PMID:16169252

  4. Foreground segmentation in depth imagery using depth and spatial dynamic models for video surveillance applications.

    PubMed

    del-Blanco, Carlos R; Mantecón, Tomás; Camplani, Massimo; Jaureguizar, Fernando; Salgado, Luis; García, Narciso

    2014-01-01

    Low-cost systems that can obtain a high-quality foreground segmentation almost independently of the existing illumination conditions for indoor environments are very desirable, especially for security and surveillance applications. In this paper, a novel foreground segmentation algorithm that uses only a Kinect depth sensor is proposed to satisfy the aforementioned system characteristics. This is achieved by combining a mixture of Gaussians-based background subtraction algorithm with a new Bayesian network that robustly predicts the foreground/background regions between consecutive time steps. The Bayesian network explicitly exploits the intrinsic characteristics of the depth data by means of two dynamic models that estimate the spatial and depth evolution of the foreground/background regions. The most remarkable contribution is the depth-based dynamic model that predicts the changes in the foreground depth distribution between consecutive time steps. This is a key difference with regard to visible imagery,where the color/gray distribution of the foreground is typically assumed to be constant.Experiments carried out on two different depth-based databases demonstrate that the proposed combination of algorithms is able to obtain a more accurate segmentation of the foreground/background than other state-of-the art approaches. PMID:24469352

  5. Foreground Segmentation in Depth Imagery Using Depth and Spatial Dynamic Models for Video Surveillance Applications

    PubMed Central

    del-Blanco, Carlos R.; Mantecón, Tomás; Camplani, Massimo; Jaureguizar, Fernando; Salgado, Luis; García, Narciso

    2014-01-01

    Low-cost systems that can obtain a high-quality foreground segmentation almost independently of the existing illumination conditions for indoor environments are very desirable, especially for security and surveillance applications. In this paper, a novel foreground segmentation algorithm that uses only a Kinect depth sensor is proposed to satisfy the aforementioned system characteristics. This is achieved by combining a mixture of Gaussians-based background subtraction algorithm with a new Bayesian network that robustly predicts the foreground/background regions between consecutive time steps. The Bayesian network explicitly exploits the intrinsic characteristics of the depth data by means of two dynamic models that estimate the spatial and depth evolution of the foreground/background regions. The most remarkable contribution is the depth-based dynamic model that predicts the changes in the foreground depth distribution between consecutive time steps. This is a key difference with regard to visible imagery, where the color/gray distribution of the foreground is typically assumed to be constant. Experiments carried out on two different depth-based databases demonstrate that the proposed combination of algorithms is able to obtain a more accurate segmentation of the foreground/background than other state-of-the art approaches. PMID:24469352

  6. Optimization and Application of Median Filter Corrections to Relieve Diverse Spatial Patterns in Microtiter Plate Data

    PubMed Central

    Bushway, Paul J.; Azimi, Behrad; Heynen-Genel, Susanne

    2014-01-01

    The standard (STD) 5 × 5 hybrid median filter (HMF) was previously described as a nonparametric local backestimator of spatially arrayed microtiter plate (MTP) data. As such, the HMF is a useful tool for mitigating global and sporadic systematic error in MTP data arrays. Presented here is the first known HMF correction of a primary screen suffering from systematic error best described as gradient vectors. Application of the STD 5 × 5 HMF to the primary screen raw data reduced background signal deviation, thereby improving the assay dynamic range and hit confirmation rate. While this HMF can correct gradient vectors, it does not properly correct periodic patterns that may present in other screening campaigns. To address this issue, 1 × 7 median and a row/column 5 × 5 hybrid median filter kernels (1 × 7 MF and RC 5 × 5 HMF) were designed ad hoc, to better fit periodic error patterns. The correction data show periodic error in simulated MTP data arrays is reduced by these alternative filter designs and that multiple corrective filters can be combined in serial operations for progressive reduction of complex error patterns in a MTP data array. PMID:21900202

  7. An electrostatic spatial resonance model for coaxial helical structures with applications to the filamentous bacteriophages.

    PubMed Central

    Marzec, C J; Day, L A

    1994-01-01

    A model is presented that treats the symmetry matching problem in structures made of two interacting coaxial helices of point charges. The charges are sources of a potential field that mediates a non-specific attractive interaction between the helices. The problem is represented in Fourier space, which affords the most generality. It is found that coaxial helices with optimally mated symmetries can lock into spatial resonance configurations that maximize their interaction. The resonances are represented as vectors in a discrete three-dimensional space. Two algebraic relations are given for the four symmetry parameters of two helices in resonance. One-start inner helices interacting with coaxial one-start or NR-start outer helices are considered. Applications are made to the filamentous bacteriophages Ff, Pf1, Xf, and Pf3. The interaction given by the linearized Poisson-Boltzmann equation is calculated in this formalism to allow comparison of the electrostatic free energy of interaction of different resonance structures. Experimental nucleotide/subunit ratios are accounted for, and models for the DNA-protein interfaces are presented, with particular emphasis on Pf1. PMID:7696463

  8. Talking and driving: applications of crossmodal action reveal a special role for spatial language

    Microsoft Academic Search

    Paul Atchley; Jeff Dressel; Todd C. Jones; Rebecca A. Burson; David Marshall

    Talking reduces attention resulting in real-world crash risks to drivers that talk on a phone and drive. Driving is a behavior\\u000a that is very demanding on spatial attention, suggesting potentially large interference by spatial codes in language. The current\\u000a study investigated how different types of verbal codes influence visual attention during dual-task performance. In two experiments,\\u000a participants performed a spatial

  9. Knowledge discovery in databases process in developing countries industry: Building an IT infrastructure based in a data warehousing and OLAP technology for a quality management system of an Electronic manufacturing company in México

    Microsoft Academic Search

    Jorge Luis Gonzalez Trujillo; Gabriel Nafarrate Vazquez

    2008-01-01

    The purpose of this article is to demonstrate that a construction and use of an IT infrastructure based in a Data Warehouse and OLAP Technology can provide of a mechanism for data recuperation and data analysis faster and more reliable than current technology applied, and as fast and reliable as any other technology used for the same purpose. This IT

  10. Application Of New Spatial Statistical Stream Models For Precise Downscaling Of Climate Change Effects On Temperatures In River Networks

    NASA Astrophysics Data System (ADS)

    Isaak, D.; Luce, C.; Peterson, E.

    2009-12-01

    A warming climate will bring unprecedented changes to stream and river ecosystems, with temperature considerations being of utmost importance, given that most aquatic organisms are ectothermic. Previous broad-scale assessments of climate impacts to streams have been limited by inadequate availability of stream temperature data and often relied on surrogate relationships between air temperature and elevation that are often imprecise. Mechanistic models have sometimes been used to model stream thermal responses directly, but intensive parameterization limits the spatial scope of these applications. Modeling approaches are needed that address stream temperatures directly at the larger spatial scales commensurate with most conservation and restoration planning efforts. We applied new spatial statistical models that account for network topology (i.e., flow direction and volume) to an extensive, but non-random stream temperature database (n = 780) compiled across a 13 year period (1993-2006) for a large (2,500 km) mountain river network in central Idaho. Four predictors—radiation, elevation, air temperature, and stream flow—were used in the spatial model to represent important geomorphic and climatic effects on mean summer stream temperatures. The spatial models accounted for autocorrelation among sample sites to provide improved parameter estimates and predictive accuracy (R2 = 0.93; RMSPE = 0.74?C) relative to traditional, non-spatial models (R2 = 0.68; RMSPE = 1.53?C). A small bias between observed stream temperatures and those predicted by the spatial models amounted to 0.5?C at the extremes of the observed temperature range (5?C - 20?C) and caused over- (under-) predictions for the coldest (warmest) streams. This bias could have arisen from elevational gradients associated with influxes of cold, snowmelt groundwater or alterations in valley form due to past glacial activity. Better understanding regarding the importance of these and other factors that effect local variability in stream warming rates is needed to optimize future downscaling efforts. However, the application of spatial models for streams provides a significant advance in our ability to translate climate change impacts to aquatic ecosystems. Moreover, the approach is widely applicable given the advent of GIS capabilities, increasing availability of stream temperature sensor networks, and flexibility to accommodate climatic forcing data from a variety of sources.

  11. Spatial variations of field polarization and phase in microwave cavities: application to the cesium fountain cavity

    Microsoft Academic Search

    A. Khursheed; G. Vecchi; A. De Marchi

    1994-01-01

    Wall losses in microwave cavities induce spatial phase variations in all held components. These variations depend on the component and can often be studied separately for each component by the use of suitable transmission line models. By a complete electromagnetic approach the phase relation between different components can be easily found, along with spatial variations, and it can be pointed

  12. An Application of Brunerian Theory to Instructional Simulation: Spatial Visualization, Factorial Research Designs, and Wooden Blocks.

    ERIC Educational Resources Information Center

    Winer, Laura R.

    A study was conducted to test the hypothesis that Brunerian learning theory can provide the instructional designer with a framework for developing effective learning materials. To determine three levels of spatial ability, two standardized tests--the Spatial Visualization Test (SVT) of the Dailey Vocational Tests and part VI of the…

  13. Bayesian Model Averaging in the Context of Spatial Hedonic Pricing: An Application to Farmland Values

    Microsoft Academic Search

    Geerte Cotteleer; Tracy Stobbe; G. Cornelis van Kooten

    2007-01-01

    Since 1973, British Columbia created an Agricultural Land Reserve to protect farmland from development. In this study, we employ GIS-based hedonic pricing models of farmland values to examine factors that affect farmland prices. We take spatial lag and error dependence into explicit account. However, the use of spatial econometric techniques in hedonic pricing models is problematic because there is uncertainty

  14. Spatial resolution in CBCT machines for dental/maxillofacial applications-what do we know today?

    PubMed

    Brüllmann, D; Schulze, R K W

    2015-01-01

    Spatial resolution is one of the most important parameters objectively defining image quality, particularly in dental imaging, where fine details often have to be depicted. Here, we review the current status on assessment parameters for spatial resolution and on published data regarding spatial resolution in CBCT images. The current concepts of visual [line-pair (lp) measurements] and automated [modulation transfer function (MTF)] assessment of spatial resolution in CBCT images are summarized and reviewed. Published measurement data on spatial resolution in CBCT are evaluated and analysed. Effective (i.e. actual) spatial resolution available in CBCT images is being influenced by the two-dimensional detector, the three-dimensional reconstruction process, patient movement during the scan and various other parameters. In the literature, the values range between 0.6 and 2.8?lp?mm(-1) (visual assessment; median, 1.7?lp?mm(-1)) vs MTF (range, 0.5-2.3?cycles per mm; median, 2.1?lp?mm(-1)). Spatial resolution of CBCT images is approximately one order of magnitude lower than that of intraoral radiographs. Considering movement, scatter effects and other influences in real-world scans of living patients, a realistic spatial resolution of just above 1?lp?mm(-1) could be expected. PMID:25168812

  15. Generation of high spatial and temporal resolution NDVI and its application in crop biomass estimation

    Microsoft Academic Search

    Jihua Meng; Xin Du; Bingfang Wu

    2011-01-01

    While data like HJ-1 CCD images have advantageous spatial characteristics for describing crop properties, the temporal resolution of the data is rather low, which can be easily made worse by cloud contamination. In contrast, although Moderate Resolution Imaging Spectroradiometer (MODIS) can only achieve a spatial resolution of 250 m in its normalised difference vegetation index (NDVI) product, it has a

  16. Application of GIS to analyze the spatial-temporal service gap for Hsinchu City bus system

    Microsoft Academic Search

    Jau-Ming Su; Cheng-Chen Kou; Mei-Hui Shen; Wen-Chi Ho; Chih-Hung Chang

    2011-01-01

    With the vision of sustainable transportation development, government authorities in Taiwan have been aggressively developing seamless environment for public transportation services in the hopes of satisfying the general users need for spatial as well as temporal seamless transportation services. The main objective of this study was to develop indexes capable of assessing the spatial-temporal service gaps of Hsinchu City bus

  17. The application of spatial filtering methods to urban feature analysis using digital image data

    Microsoft Academic Search

    M. J. DUGGIN; R. A. ROWNTREE; A. W. ODELL

    1988-01-01

    We describe a method of spatial filtering in the frequency domain which enhances edges and boundaries, thus making small urban features such as parks, tree-lined streets and new housing developments, visible on digital images with, for example, 30 m resolution. Hitherto, while satellite imagery has been useful because of its large area and repetitive coverage, the spatial resolution for multiband

  18. Spatial Double Generalized Beta Regression Models: Extensions and Application to Study Quality of Education in Colombia

    ERIC Educational Resources Information Center

    Cepeda-Cuervo, Edilberto; Núñez-Antón, Vicente

    2013-01-01

    In this article, a proposed Bayesian extension of the generalized beta spatial regression models is applied to the analysis of the quality of education in Colombia. We briefly revise the beta distribution and describe the joint modeling approach for the mean and dispersion parameters in the spatial regression models' setting. Finally, we…

  19. Application of spatial Poisson process models to air mass thunderstorm rainfall

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.; Fennessy, N. M.; Wang, Qinliang; Rodriguez-Iturbe, I.

    1987-01-01

    Eight years of summer storm rainfall observations from 93 stations in and around the 154 sq km Walnut Gulch catchment of the Agricultural Research Service, U.S. Department of Agriculture, in Arizona are processed to yield the total station depths of 428 storms. Statistical analysis of these random fields yields the first two moments, the spatial correlation and variance functions, and the spatial distribution of total rainfall for each storm. The absolute and relative worth of three Poisson models are evaluated by comparing their prediction of the spatial distribution of storm rainfall with observations from the second half of the sample. The effect of interstorm parameter variation is examined.

  20. Bivariate B-splines and its Applications in Spatial Data Analysis

    E-print Network

    Pan, Huijun 1987-

    2011-08-09

    nonparametric spatial surface fitting problems. In particular, the third part develops a penalized B-splines method to reconstruct a smooth surface from noisy observations. A numerical algorithm is derived, implemented, and applied to simulated and real data...

  1. Automated Spatial-Semantic Modeling with Applications to Place Labeling and Informed Search

    E-print Network

    Mackworth, Alan K.

    , this system represents a new level in spatial reasoning and semantic under- standing for a physical platform wheelchair needs to know the location of the kitchen in order to guide its cognitively- impaired driver

  2. Shift-Share Analysis with Spatial Structure: an Application to Italian Industrial Districts

    Microsoft Academic Search

    Gian Pietro Zaccomer

    2006-01-01

    Shift-share analysis is a well-known and widely used tool for spatial data analysis, though it presents some weaknesses and\\u000a limitations. In this paper we aim to extend this technique by introducing a spatial structure in the particular case of Italian\\u000a industrial districts. This extension is possible due to the use of enterprise legal status, together with activity information,\\u000a available on

  3. R-vine models for spatial time series with an application to daily mean temperature.

    PubMed

    Erhardt, Tobias Michael; Czado, Claudia; Schepsmeier, Ulf

    2015-06-01

    We introduce an extension of R-vine copula models to allow for spatial dependencies and model based prediction at unobserved locations. The proposed spatial R-vine model combines the flexibility of vine copulas with the classical geostatistical idea of modeling spatial dependencies using the distances between the variable locations. In particular, the model is able to capture non-Gaussian spatial dependencies. To develop and illustrate our approach, we consider daily mean temperature data observed at 54 monitoring stations in Germany. We identify relationships between the vine copula parameters and the station distances and exploit these in order to reduce the huge number of parameters needed to parametrize a 54-dimensional R-vine model fitted to the data. The new distance based model parametrization results in a distinct reduction in the number of parameters and makes parameter estimation and prediction at unobserved locations feasible. The prediction capabilities are validated using adequate scoring techniques, showing a better performance of the spatial R-vine copula model compared to a Gaussian spatial model. PMID:25660495

  4. Application of spatially referenced regression modeling for the evaluation of total nitrogen loading in the Chesapeake Bay watershed

    USGS Publications Warehouse

    Preston, Stephen D.; Brakebill, John W.

    1999-01-01

    The reduction of stream nutrient loads is an important part of current efforts to improve water quality in the Chesapeake Bay. To design programs that will effectively reduce stream nutrient loading, resource managers need spatially detailed information that describes the location of nutrient sources and the watershed factors that affect delivery of nutrients to the Bay. To address this need, the U.S. Geological Survey has developed a set of spatially referenced regression models for the evaluation of nutrient loading in the watershed. The technique applied for this purpose is referred to as ?SPARROW? (SPAtially Referenced Regressions On Watershed attributes), which is a statistical modeling approach that retains spatial referencing for illustrating predictions, and for relating upstream nutrient sources to downstream nutrient loads. SPARROW is based on a digital stream-network data set that is composed of stream segments (reaches) that are attributed with traveltime and connectivity information. Drainage-basin boundaries are defined for each stream reach in the network data set through the use of a digital elevation model. For the Chesapeake Bay watershed, the spatial network was developed using the U.S. Environmental Protection Agency?s River Reach File 1 digital stream network, and is composed of 1,408 stream reaches and watershed segments. To develop a SPARROW model for total nitrogen in the Chesapeake Bay watershed, data sets for sources and basin characteristics were incorporated into the spatial network and related to stream-loading information by using a nonlinear regression model approach. Total nitrogen source variables that were statistically significant in the model include point sources, urban area, fertilizer application, manure generation and atmospheric deposition. Total nitrogen loss variables that were significant in the model include soil permeability and instream-loss rates for four stream-reach classes. Applications of SPARROW for evaluating total nitrogen loading in the Chesapeake Bay watershed include the illustration of the spatial distributions of total nitrogen yields and of the potential for delivery of those yields to the Bay. This information is being used by the Chesapeake Bay Program to target nutrient-reduction areas (Priority Nutrient Reduction Areas) and to design nutrient-load reduction plans that are specific to each tributary (Tributary Strategies).

  5. SPHARA - A Generalized Spatial Fourier Analysis for Multi-Sensor Systems with Non-Uniformly Arranged Sensors: Application to EEG.

    PubMed

    Graichen, Uwe; Eichardt, Roland; Fiedler, Patrique; Strohmeier, Daniel; Zanow, Frank; Haueisen, Jens

    2015-01-01

    Important requirements for the analysis of multichannel EEG data are efficient techniques for signal enhancement, signal decomposition, feature extraction, and dimensionality reduction. We propose a new approach for spatial harmonic analysis (SPHARA) that extends the classical spatial Fourier analysis to EEG sensors positioned non-uniformly on the surface of the head. The proposed method is based on the eigenanalysis of the discrete Laplace-Beltrami operator defined on a triangular mesh. We present several ways to discretize the continuous Laplace-Beltrami operator and compare the properties of the resulting basis functions computed using these discretization methods. We apply SPHARA to somatosensory evoked potential data from eleven volunteers and demonstrate the ability of the method for spatial data decomposition, dimensionality reduction and noise suppression. When employing SPHARA for dimensionality reduction, a significantly more compact representation can be achieved using the FEM approach, compared to the other discretization methods. Using FEM, to recover 95% and 99% of the total energy of the EEG data, on average only 35% and 58% of the coefficients are necessary. The capability of SPHARA for noise suppression is shown using artificial data. We conclude that SPHARA can be used for spatial harmonic analysis of multi-sensor data at arbitrary positions and can be utilized in a variety of other applications. PMID:25885290

  6. Krylov implicit integration factor methods for spatial discretization on high dimensional unstructured meshes: Application to discontinuous Galerkin methods

    NASA Astrophysics Data System (ADS)

    Chen, Shanqin; Zhang, Yong-Tao

    2011-05-01

    Integration factor methods are a class of "exactly linear part" time discretization methods. In [Q. Nie, Y.-T. Zhang, R. Zhao, Efficient semi-implicit schemes for stiff systems, Journal of Computational Physics, 214 (2006) 521-537], a class of efficient implicit integration factor (IIF) methods were developed for solving systems with both stiff linear and nonlinear terms, arising from spatial discretization of time-dependent partial differential equations (PDEs) with linear high order terms and stiff lower order nonlinear terms. The tremendous challenge in applying IIF temporal discretization for PDEs on high spatial dimensions is how to evaluate the matrix exponential operator efficiently. For spatial discretization on unstructured meshes to solve PDEs on complex geometrical domains, how to efficiently apply the IIF temporal discretization was open. In this paper, we solve this problem by applying the Krylov subspace approximations to the matrix exponential operator. Then we apply this novel time discretization technique to discontinuous Galerkin (DG) methods on unstructured meshes for solving reaction-diffusion equations. Numerical examples are shown to demonstrate the accuracy, efficiency and robustness of the method in resolving the stiffness of the DG spatial operator for reaction-diffusion PDEs. Application of the method to a mathematical model in pattern formation during zebrafish embryo development shall be shown.

  7. Multilevel Modelling with Spatial Interaction Effects with Application to an Emerging Land Market in Beijing, China

    PubMed Central

    Dong, Guanpeng; Harris, Richard; Jones, Kelvyn; Yu, Jianhui

    2015-01-01

    This paper develops a methodology for extending multilevel modelling to incorporate spatial interaction effects. The motivation is that classic multilevel models are not specifically spatial. Lower level units may be nested into higher level ones based on a geographical hierarchy (or a membership structure—for example, census zones into regions) but the actual locations of the units and the distances between them are not directly considered: what matters is the groupings but not how close together any two units are within those groupings. As a consequence, spatial interaction effects are neither modelled nor measured, confounding group effects (understood as some sort of contextual effect that acts ‘top down’ upon members of a group) with proximity effects (some sort of joint dependency that emerges between neighbours). To deal with this, we incorporate spatial simultaneous autoregressive processes into both the outcome variable and the higher level residuals. To assess the performance of the proposed method and the classic multilevel model, a series of Monte Carlo simulations are conducted. The results show that the proposed method performs well in retrieving the true model parameters whereas the classic multilevel model provides biased and inefficient parameter estimation in the presence of spatial interactions. An important implication of the study is to be cautious of an apparent neighbourhood effect in terms of both its magnitude and statistical significance if spatial interaction effects at a lower level are suspected. Applying the new approach to a two-level land price data set for Beijing, China, we find significant spatial interactions at both the land parcel and district levels. PMID:26086913

  8. Application of Spatial Modelling Approaches, Sampling Strategies and 3s Technology Within AN Ecolgocial Framwork

    NASA Astrophysics Data System (ADS)

    Chen, H.-C.; Lo, N.-J.; Chang, W.-I.; Huang, K.-Y.

    2012-07-01

    How to effectively describe ecological patterns in nature over broader spatial scales and build a modeling ecological framework has become an important issue in ecological research. We test four modeling methods (MAXENT, DOMAIN, GLM and ANN) to predict the potential habitat of Schima superba (Chinese guger tree, CGT) with different spatial scale in the Huisun study area in Taiwan. Then we created three sampling design (from small to large scales) for model development and validation by different combinations of CGT samples from aforementioned three sites (Tong-Feng watershed, Yo-Shan Mountain, and Kuan-Dau watershed). These models combine points of known occurrence and topographic variables to infer CGT potential spatial distribution. Our assessment revealed that the method performance from highest to lowest was: MAXENT, DOMAIN, GLM and ANN on small spatial scale. The MAXENT and DOMAIN two models were the most capable for predicting the tree's potential habitat. However, the outcome clearly indicated that the models merely based on topographic variables performed poorly on large spatial extrapolation from Tong-Feng to Kuan-Dau because the humidity and sun illumination of the two watersheds are affected by their microterrains and are quite different from each other. Thus, the models developed from topographic variables can only be applied within a limited geographical extent without a significant error. Future studies will attempt to use variables involving spectral information associated with species extracted from high spatial, spectral resolution remotely sensed data, especially hyperspectral image data, for building a model so that it can be applied on a large spatial scale.

  9. An effective method for resolving spatial distribution of adsorption kinetics in heterogeneous porous media: application for carbon dioxide sequestration in coal

    Microsoft Academic Search

    C. Özgen Karacan

    2003-01-01

    In adsorption studies, equilibrium adsorption properties are relatively easy to determine compared to kinetic parameters. Especially, it is not possible to study the spatial distribution of adsorption kinetics in structurally heterogeneous adsorbents by the available and almost standardized macroscopic methods. This paper presents application of quantitative X-ray computerized tomography (CT) imaging in investigating the spatial distribution of adsorption kinetics. The

  10. Spatially regularized mixture model for lesion segmentation with application to stroke patients.

    PubMed

    Ozenne, Brice; Subtil, Fabien; Østergaard, Leif; Maucort-Boulch, Delphine

    2015-07-01

    In medical imaging, lesion segmentation (differentiation between lesioned and non-lesioned tissue) is a crucial and difficult task. Automated segmentation algorithms based on intensity analysis have been already proposed and recent developments have shown that integrating spatial information enhances automatic image segmentation. However, spatial modeling is often limited to short-range spatial interactions that deal only with noise or small artifacts. Previous tissue alterations (e.g. white matter disease (WMD)) similar in intensity with the lesion of interest require a broader-scale approach to be corrected. On the other hand, imaging techniques offer now a multiparametric voxel characterization that may help differentiating lesioned from non-lesioned voxels. We developed an unsupervised multivariate segmentation algorithm based on finite mixture modeling that incorporates spatial information. We extended the usual spatial Potts model to the regional scale using a 'multi-order' neighborhood potential, with internal adjustment of the regional scale according to the lesion size. We validate the ability of this new algorithm to deal with noise and artifacts (linear and spherical) using artificial data. We then assess its performance on real magnetic resonance imaging brain scans of stroke patients with history of WMD and show that regional regularization was able to remove large-scale WMD artifacts. PMID:25745872

  11. Spatial sampling considerations and their applications to characterizing fractured rock and karst systems

    NASA Astrophysics Data System (ADS)

    Benson, R. C.; Yuhr, L.

    1993-12-01

    Assessing the existence, location, and mapping of geologic anomalies, such as fractures and cavities within soil and rock, are common to both engineering and hydrologic project needs. There are numerous measurement techniques available to detect, map, and characterize fractures and cavities. A summary of the common methods available for fracture and cavity detection and mapping are presented along with their spatial sampling capabilities. The remote sensing and geophysical methods are but a small part of this list but provide a wide range of tools to attack the problem. They include some of the most effective methods for locating and mapping fractures and cavities and cover the complete range of spatial sampling, from regional to no more than the surface of a borehole wall. An understanding of all of the tools available and their spatial sampling limitations is a necessary part of planning and carrying out an effective fracture/cavity investigation.

  12. Application of adaptive optics in complicated and integrated spatial multisensor system and its measurement analysis

    NASA Astrophysics Data System (ADS)

    Ding, Quanxin; Guo, Chunjie; Cai, Meng; Liu, Hua

    2007-12-01

    Adaptive Optics Expand System is a kind of new concept spatial equipment, which concerns system, cybernetics and informatics deeply, and is key way to improve advanced sensors ability. Traditional Zernike Phase Contrast Method is developed, and Accelerated High-level Phase Contrast Theory is established. Integration theory and mathematical simulation is achieved. Such Equipment, which is based on some crucial components, such as, core optical system, multi mode wavefront sensor and so on, is established for AOES advantageous configuration and global design. Studies on Complicated Spatial Multisensor System Integratation and measurement Analysis including error analysis are carried out.

  13. SpPack: spatial point pattern analysis in Excel using Visual Basic for Applications (VBA)

    Microsoft Academic Search

    George L. W. Perry

    2004-01-01

    Many different sciences have developed many different tests to describe and characterise spatial point data. For example, all the trees in a given area may be mapped such that their x, y co-ordinates and other variables, or ‘marks’, (e.g. species, size) might be recorded. Statistical techniques can be used to explore interactions between events at different length scales and interactions

  14. Bayesian parametric accelerated failure time spatial model and its application to prostate cancer

    Microsoft Academic Search

    Jiajia Zhang; Andrew B. Lawson

    2011-01-01

    Prostate cancer (PrCA) is the most common cancer diagnosed in American men and the second leading cause of death from malignancies. There are large geographical variation and racial disparities existing in the survival rate of PrCA. Much work on the spatial survival model is based on the proportional hazards (PH) model, but few focused on the accelerated failure time (AFT)

  15. Bivariate B-splines and its Applications in Spatial Data Analysis 

    E-print Network

    Pan, Huijun 1987-

    2011-08-09

    In the field of spatial statistics, it is often desirable to generate a smooth surface for a region over which only noisy observations of the surface are available at some locations, or even across time. Kriging and kernel estimations are two...

  16. Spatial targeting using queries in a 3-D GIS environment with application to mineral exploration

    Microsoft Academic Search

    Kevin Sprague; Eric de Kemp; Winston Wong; John McGaughey; Gervais Perron; Tucker Barrie

    2006-01-01

    A query framework for spatial targeting within a 3-D geographic information system (GIS) software environment is introduced. Input to a query consists of parameters relevant to the query type together with a set of Common Earth Modelling objects represented as point sets, polygonal lines, surfaces, and grids or a region set (subset) thereof. The result of a 3-D GIS query

  17. Spatial decision support and information management application to wildland fire prevention The WILFRIED System

    Microsoft Academic Search

    F. Guarniéri; J. L. Wybo

    1995-01-01

    This paper presents an integrated Spatial Decision Support System (SDSS), called WILFRIED, which is designed to fit the requirements of managers in charge of wildland fire prevention and fighting. To achieve decision support, the system combines tasks: it gives the user an efficient access to relevant data, synthesizes pertinent information (meteorology, topography, vegetation) and automates repetitive tasks (compute the wind

  18. Application of REAL TIME GIS for Local Government and Collaboration of Spatial Information

    Microsoft Academic Search

    Aki Okuno; Sota Shimano; Masaaki Shikada

    2006-01-01

    Much local government has been using large scale digital maps with geographic information system (GIS). However, the updating method of a map is not established yet. The purpose of this study is the real-time renewal of the digital map for local government by using REAR TIME GIS and spatial information. REAL TIME GIS is the system for real-time updating at

  19. Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling

    USGS Publications Warehouse

    Brakebill, J.W.; Wolock, D.M.; Terziotti, S.E.

    2011-01-01

    Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents throughout the landscape. Digital hydrologic networks have evolved from derivatives of mapping products to detailed, interconnected, spatially referenced networks of water pathways, drainage areas, and stream and watershed characteristics. These properties are important because they enhance the ability to spatially evaluate factors that affect the sources and transport of water-quality constituents at various scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW), a process-based/statistical model, relies on a digital hydrologic network in order to establish relations between quantities of monitored contaminant flux, contaminant sources, and the associated physical characteristics affecting contaminant transport. Digital hydrologic networks modified from the River Reach File (RF1) and National Hydrography Dataset (NHD) geospatial datasets provided frameworks for SPARROW in six regions of the conterminous United States. In addition, characteristics of the modified RF1 were used to update estimates of mean-annual streamflow. This produced more current flow estimates for use in SPARROW modeling. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  20. Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling1

    PubMed Central

    Brakebill, JW; Wolock, DM; Terziotti, SE

    2011-01-01

    Abstract Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents throughout the landscape. Digital hydrologic networks have evolved from derivatives of mapping products to detailed, interconnected, spatially referenced networks of water pathways, drainage areas, and stream and watershed characteristics. These properties are important because they enhance the ability to spatially evaluate factors that affect the sources and transport of water-quality constituents at various scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW), a process-based/statistical model, relies on a digital hydrologic network in order to establish relations between quantities of monitored contaminant flux, contaminant sources, and the associated physical characteristics affecting contaminant transport. Digital hydrologic networks modified from the River Reach File (RF1) and National Hydrography Dataset (NHD) geospatial datasets provided frameworks for SPARROW in six regions of the conterminous United States. In addition, characteristics of the modified RF1 were used to update estimates of mean-annual streamflow. This produced more current flow estimates for use in SPARROW modeling. PMID:22457575

  1. Dynamic spatially-explicit mass-balance modeling for targeted watershed phosphorus management II: Model Application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cost-effective nonpoint source phosphorus (P) control should target the land areas at greatest risk for P loss. We combined mass-balance modeling and geographic analysis to identify and map high-risk areas for P export by integrating long-term P input/output accounting with spatially variable physi...

  2. Bayesian two-part spatial models for semicontinuous data with application to emergency department expenditures.

    PubMed

    Neelon, Brian; Zhu, Li; Neelon, Sara E Benjamin

    2015-07-01

    In health services research, it is common to encounter semicontinuous data characterized by a point mass at zero and a continuous distribution of positive values. Examples include medical expenditures, in which the zeros represent patients who do not use health services, while the continuous distribution describes the level of expenditures among users. Semicontinuous data are customarily analyzed using two-part mixture models. In the spatial analysis of semicontinuous data, two-part models are especially appealing because they provide a joint picture of how health services utilization and associated expenditures vary across geographic regions. However, when applying these models, careful attention must be paid to distributional choices, as model misspecification can lead to biased and imprecise inferences. This paper introduces a broad class of Bayesian two-part models for the spatial analysis of semicontinuous data. Specific models considered include two-part lognormal, log skew-elliptical, and Bayesian non-parametric models. Multivariate conditionally autoregressive priors are used to link model components and provide spatial smoothing across neighboring regions, resulting in a joint spatial modeling framework for health utilization and expenditures. We develop a fully conjugate Gibbs sampling scheme, leading to efficient posterior computation. We illustrate the approach using data from a recent study of emergency department expenditures. PMID:25649743

  3. Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling.

    PubMed

    Brakebill, Jw; Wolock, Dm; Terziotti, Se

    2011-10-01

    Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents throughout the landscape. Digital hydrologic networks have evolved from derivatives of mapping products to detailed, interconnected, spatially referenced networks of water pathways, drainage areas, and stream and watershed characteristics. These properties are important because they enhance the ability to spatially evaluate factors that affect the sources and transport of water-quality constituents at various scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW), a process-based/statistical model, relies on a digital hydrologic network in order to establish relations between quantities of monitored contaminant flux, contaminant sources, and the associated physical characteristics affecting contaminant transport. Digital hydrologic networks modified from the River Reach File (RF1) and National Hydrography Dataset (NHD) geospatial datasets provided frameworks for SPARROW in six regions of the conterminous United States. In addition, characteristics of the modified RF1 were used to update estimates of mean-annual streamflow. This produced more current flow estimates for use in SPARROW modeling. PMID:22457575

  4. Application of Spatial Bandwidth Concepts to MAS Pole Location for Dielectric Cylinders

    Microsoft Academic Search

    James E. Richie

    2011-01-01

    The concept of effective spatial bandwidth (EBW) is extended from the case of an MAS solution for perfectly conducting (PEC) cylinders to dielectric cylinders. It is shown that the ideas and results for the con- ducting cylinder apply in a straightforward manner to the dielectric case. For the dielectric case, there are two auxiliary surfaces. Because the EBW calculations are

  5. Spatial Gaussian Filtering of Bayer Images with Applications to Color Segmentation

    Microsoft Academic Search

    Johannes Herwig; Josef Pauli

    A single sensor color imaging device has a color filter array (CFA) laid on top of its photodiodes, which spatially samples bandpassed spectral responses. Hence, with the popular Bayer pattern, at every pixel site either red, green or blue light is measured. A process known as demosaicing interpolates the vector-valued color image from the scalar-valued sensor output, termed here as

  6. A study on spatial coherence using quadratic radially distributed apertures (application to confocal imaging)

    Microsoft Academic Search

    A. M. Named

    1997-01-01

    We study the spatial coherence problem using an amplitude modulation applied to confocal imaging systems. This type of modulation assumes a quadratic radial distribution. The mutual coherence intensity or the coherence factor is calculated and compared with the results obtained for clear circular apertures.

  7. Applications of geographical information systems (GIS) for spatial decision support in aquaculture

    Microsoft Academic Search

    Shree S. Nath; John P. Bolte; Lindsay G. Ross; Jose Aguilar-Manjarrez

    2000-01-01

    Geographical information systems (GIS) are becoming an increasingly integral component of natural resource management activities worldwide. However, despite some indication that these tools are receiving attention within the aquaculture community, their deployment for spatial decision support in this domain continues to be very slow. This situation is attributable to a number of constraints including a lack of appreciation of the

  8. A Simplified Program for Detecting Item Bias and Its Application to a Spatial Visualization Test.

    ERIC Educational Resources Information Center

    Jones, Martha S.; Vredevoogd, Janet

    This study was designed to determine item bias by sex on a test of spatial visualization administered to middle school students. Two chi square techniques were used to assess item bias: the Scheuneman C2 and the Camilli chi square. The direction of bias was indicated by assigning positive signs to the chi square components contributed by one group…

  9. INTEGRATING HYDROLOGIC MODELS AND SPATIAL DATA IN A DISTRIBUTED INTERNET APPLICATION 1801

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DotAGWA is a shared application used to assist watershed planners in decision making processes and to offset the software and data requirements typically required in a desktop application. The features available in DotAGWA help planners share and visualize data. Groups can interact with the applic...

  10. Visualization and Analysis of Wireless Sensor Network Data for Smart Civil Structure Applications Based On Spatial Correlation Technique

    NASA Astrophysics Data System (ADS)

    Chowdhry, Bhawani Shankar; White, Neil M.; Jeswani, Jai Kumar; Dayo, Khalil; Rathi, Manorma

    2009-07-01

    Disasters affecting infrastructure, such as the 2001 earthquakes in India, 2005 in Pakistan, 2008 in China and the 2004 tsunami in Asia, provide a common need for intelligent buildings and smart civil structures. Now, imagine massive reductions in time to get the infrastructure working again, realtime information on damage to buildings, massive reductions in cost and time to certify that structures are undamaged and can still be operated, reductions in the number of structures to be rebuilt (if they are known not to be damaged). Achieving these ideas would lead to huge, quantifiable, long-term savings to government and industry. Wireless sensor networks (WSNs) can be deployed in buildings to make any civil structure both smart and intelligent. WSNs have recently gained much attention in both public and research communities because they are expected to bring a new paradigm to the interaction between humans, environment, and machines. This paper presents the deployment of WSN nodes in the Top Quality Centralized Instrumentation Centre (TQCIC). We created an ad hoc networking application to collect real-time data sensed from the nodes that were randomly distributed throughout the building. If the sensors are relocated, then the application automatically reconfigures itself in the light of the new routing topology. WSNs are event-based systems that rely on the collective effort of several micro-sensor nodes, which are continuously observing a physical phenomenon. WSN applications require spatially dense sensor deployment in order to achieve satisfactory coverage. The degree of spatial correlation increases with the decreasing inter-node separation. Energy consumption is reduced dramatically by having only those sensor nodes with unique readings transmit their data. We report on an algorithm based on a spatial correlation technique that assures high QoS (in terms of SNR) of the network as well as proper utilization of energy, by suppressing redundant data transmission. The visualization and analysis of WSN data are presented in a Windows-based user interface.

  11. Spatial oxygen distribution and nitrous oxide emissions from soil after manure application: a novel approach using planar optodes.

    PubMed

    Zhu, Kun; Bruun, Sander; Larsen, Morten; Glud, Ronnie N; Jensen, Lars Stoumann

    2014-09-01

    The availability and spatial distribution of oxygen (O) in agricultural soil are controlling factors in the production and emission of nitrous oxide (NO) to the atmosphere, but most experiments investigating the effects of various factors on NO emissions in soil have been conducted without determining the content and distribution of O. This complicates data interpretation and leads to speculative conclusions about which nitrogen transformation processes are responsible for NO production. Using an O-specific planar optode, this paper shows how spatiotemporal O dynamics can be used to interpret data on NO emissions following a uniform or layered amendment of manure to agricultural soil. The spatial distribution of O and gas emission rates were monitored for 12 h. An anoxic layer formed rapidly around the layered manure, whereas the uniformly distributed manure led to a more widespread anoxia. Nitrous oxide emissions increased immediately after depletion of O in the manure-amended treatments. Greater understanding and improved knowledge of the spatial distribution of O is clearly beneficial and can be used to devise improved application strategies for mitigating NO emissions from manure and other fertilizers. PMID:25603265

  12. Efficient sampling for spatial uncertainty qualification in multibody system dynamics applications.

    SciTech Connect

    Schmitt, K.; Anitescu, M.; Negrut, D.; Mathematics and Computer Science; Univ. of Wisconsin

    2009-01-01

    We present two methods for efficiently sampling the response (trajectory space) of multibody systems operating under spatial uncertainty, when the latter is assumed to be representable with Gaussian processes. In this case, the dynamics (time evolution) of the multibody systems depends on spatially indexed uncertain parameters that span infinite-dimensional spaces. This places a heavy computational burden on existing methodologies, an issue addressed herein with two new conditional sampling approaches. When a single instance of the uncertainty is needed in the entire domain, we use a fast Fourier transform technique. When the initial conditions are fixed and the path distribution of the dynamical system is relatively narrow, we use an incremental sampling approach that is fast and has a small memory footprint. Both methods produce the same distributions as the widely used Cholesky-based approaches. We illustrate this convergence at a smaller computational effort and memory cost for a simple non-linear vehicle model.

  13. Spatial MAC in MIMO Communications and its Application to Underlay Cognitive Radio

    E-print Network

    Noam, Yair

    2012-01-01

    We propose a learning technique for MIMO secondary users (SU) to spatially coexist with Primary Users (PU). By learning the null space of the interference channel to the PU, the SU can utilize idle degrees of freedom that otherwise would be unused by the PU. This learning process does not require any handshake or explicit information exchange between the PU and the SU. The only requirement is that the PU broadcasts a periodic beacon that is a function of its noise plus interference power, through a low rate control channel. The learning process is based on energy measurements, independent of the transmission schemes of both the PU and SU, i.e. independent of their modulation, coding etc.. The proposed learning technique also provides a novel spatial division multiple access mechanism for equal-priority MIMO users sharing a common channel that highly increases the spectrum utilization compared to time based or frequency multiple access.

  14. Quantifying patch distribution at multiple spatial scales: applications to wildlife-habitat models

    Microsoft Academic Search

    Chris J. Johnson; Mark S. Boyce; Robert Mulders; Anne Gunn; Rob J. Gau; H. Dean Cluff; Ray L. Case

    2004-01-01

    Multiscale analyses are widely employed for wildlife-habitat studies. In most cases, however, each scale is considered discrete\\u000a and little emphasis is placed on incorporating or measuring the responses of wildlife to resources across multiple scales.\\u000a We modeled the responses of three Arctic wildlife species to vegetative resources distributed at two spatial scales: patches\\u000a and collections of patches aggregated across a

  15. Spatial relationships between lingual nerve and mandibular ramus: original study method, clinical and educational applications

    Microsoft Academic Search

    Olivier Trost; Apolline Kazemi; Nicolas Cheynel; Mehdi Benkhadra; Pierre Soichot; Gabriel Malka; Pierre Trouilloud

    2009-01-01

    Lingual nerve damage complicating oral surgery would sometimes require electrographic exploration. Nevertheless, direct recording\\u000a of conduction in lingual nerve requires its puncture at the foramen ovale. This method is too dangerous to be practiced routinely\\u000a in these diagnostic indications. The aim of our study was to assess spatial relationships between lingual nerve and mandibular\\u000a ramus in the infratemporal fossa using

  16. Real-time spatial compound imaging: Application to breast, vascular, and musculoskeletal ultrasound

    Microsoft Academic Search

    Robert R Entrekin; Bruce A Porter; Henrik H Sillesen; Anthony D Wong; Peter L Cooperberg; Cathy H Fix

    2001-01-01

    Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image

  17. Application and evaluation of a measured spatially variant system model for PET image reconstruction.

    PubMed

    Alessio, Adam M; Stearns, Charles W; Tong, Shan; Ross, Steven G; Kohlmyer, Steve; Ganin, Alex; Kinahan, Paul E

    2010-03-01

    Accurate system modeling in tomographic image reconstruction has been shown to reduce the spatial variance of resolution and improve quantitative accuracy. System modeling can be improved through analytic calculations, Monte Carlo simulations, and physical measurements. The purpose of this work is to improve clinical fully-3-D reconstruction without substantially increasing computation time. We present a practical method for measuring the detector blurring component of a whole-body positron emission tomography (PET) system to form an approximate system model for use with fully-3-D reconstruction. We employ Monte Carlo simulations to show that a non-collimated point source is acceptable for modeling the radial blurring present in a PET tomograph and we justify the use of a Na22 point source for collecting these measurements. We measure the system response on a whole-body scanner, simplify it to a 2-D function, and incorporate a parameterized version of this response into a modified fully-3-D OSEM algorithm. Empirical testing of the signal versus noise benefits reveal roughly a 15% improvement in spatial resolution and 10% improvement in contrast at matched image noise levels. Convergence analysis demonstrates improved resolution and contrast versus noise properties can be achieved with the proposed method with similar computation time as the conventional approach. Comparison of the measured spatially variant and invariant reconstruction revealed similar performance with conventional image metrics. Edge artifacts, which are a common artifact of resolution-modeled reconstruction methods, were less apparent in the spatially variant method than in the invariant method. With the proposed and other resolution-modeled reconstruction methods, edge artifacts need to be studied in more detail to determine the optimal tradeoff of resolution/contrast enhancement and edge fidelity. PMID:20199927

  18. A general-purpose low-cost compact spatial-temporal data logger and its applications

    Microsoft Academic Search

    Calvin Coopmans; YangQuan Chen

    2008-01-01

    This paper presents design details of SEAL, a general-purpose low-cost spatial-temporal data logger. The SEAL module includes GPS, Lithium-ion polymer battery, high-density flash memory and a USB interface. The main features include: low cost, very large size XML-based data logs, low power consumption, flexible sensor attachment, and an optional Wi-Fi interface for Internet-enabled data. It is compact, self-contained and light-weight-suitable

  19. Comparison of three temperature control systems applications for a special homemade shortwave infrared spatial remote sensor

    Microsoft Academic Search

    Zhipeng Xu; Jun Wei; Jianwei Li; Qianting Zhou

    2010-01-01

    An image spectrometer of a spatial remote sensing satellite requires shortwave band ranging from 2.1mum to 3mum which is one of the most important bands in remote sensing. We designed an infrared sub-system of the image spectrometer using a homemade 640x1 InGaAs shortwave infrared sensor working on FPA system which requires high uniformity and low level of dark current. The

  20. Spatially aware expectation maximization (SpAEM): application to prostate TRUS segmentation

    NASA Astrophysics Data System (ADS)

    Orooji, Mahdi; Sparks, Rachel; Bloch, B. Nicolas; Feleppa, Ernest; Barratt, Dean; Madabhushi, Anant

    2014-03-01

    In this paper we introduce Spatially Aware Expectation Maximization (SpAEM), a new parameter estimation method which incorporates information pertaining to spatial prior probability into the traditional expectation- maximization framework. For estimating the parameters of a given class, the spatial prior probability allows us to weight the contribution of any pixel based on the probability of that pixel belonging to the class of interest. In this paper we evaluate SpAEM for the problem of prostate capsule segmentation in transrectal ultrasound (TRUS) images. In cohort of 6 patients, SpAEM qualitatively and quantitatively outperforms traditional EM in distinguishing the foreground (prostate) from background (non-prostate) regions by around 45% in terms of the Sorensen Dice overlap measure, when compared against expert annotations. The variance of the estimated parameters measured via Cramer-Rao Lower Bound suggests that SpAEM yields unbiased estimates. Finally, on a synthetic TRUS image, the Cramer-Von Mises (CVM) criteria shows that SpAEM improves the estimation accuracy by around 51% and 88% for prostate and background, respectively, as compared to traditional EM.

  1. Application of land use regression modelling to assess the spatial distribution of road traffic noise in three European cities.

    PubMed

    Aguilera, Inmaculada; Foraster, Maria; Basagaña, Xavier; Corradi, Elisabetta; Deltell, Alexandre; Morelli, Xavier; Phuleria, Harish C; Ragettli, Martina S; Rivera, Marcela; Thomasson, Alexandre; Slama, Rémy; Künzli, Nino

    2015-01-01

    Noise prediction models and noise maps are used to estimate the exposure to road traffic noise, but their availability and the quality of the noise estimates is sometimes limited. This paper explores the application of land use regression (LUR) modelling to assess the long-term intraurban spatial variability of road traffic noise in three European cities. Short-term measurements of road traffic noise taken in Basel, Switzerland (n=60), Girona, Spain (n=40), and Grenoble, France (n=41), were used to develop two LUR models: (a) a "GIS-only" model, which considered only predictor variables derived with Geographic Information Systems; and (b) a "Best" model, which in addition considered the variables collected while visiting the measurement sites. Both noise measurements and noise estimates from LUR models were compared with noise estimates from standard noise models developed for each city by the local authorities. Model performance (adjusted R(2)) was 0.66-0.87 for "GIS-only" models, and 0.70-0.89 for "Best" models. Short-term noise measurements showed a high correlation (r=0.62-0.78) with noise estimates from the standard noise models. LUR noise estimates did not show any systematic differences in the spatial patterns when compared with those from standard noise models. LUR modelling with accurate GIS source data can be a promising tool for noise exposure assessment with applications in epidemiological studies. PMID:25227731

  2. A spatially varying two-sample recombinant coalescent, with applications to HIV escape response

    PubMed Central

    Braunstein, Alexander; Jensen, Shane T.; Wei, Zhi; McAuliffe, Jon D.

    2010-01-01

    Statistical evolutionary models provide an important mechanism for describing and understanding the escape response of a viral population under a particular therapy. We present a new hierarchical model that incorporates spatially varying mutation and recombination rates at the nucleotide level. It also maintains separate parameters for treatment and control groups, which allows us to estimate treatment effects explicitly. We use the model to investigate the sequence evolution of HIV populations exposed to a recently developed antisense gene therapy, as well as a more conventional drug therapy. The detection of biologically relevant and plausible signals in both therapy studies demonstrates the effectiveness of the method. PMID:20531976

  3. A new spatially constrained NMF with application to fMRI.

    PubMed

    Ferdowsi, Saideh; Abolghasemi, Vahid; Makkiabadi, Bahador; Sanei, Saeid

    2011-01-01

    In this paper the problem of BOLD detection is addressed. The focus here is on non-negative matrix factorization (NMF), which is a data driven method and able to provide part-based representation of data. A new constrained optimization problem is proposed for the purpose of BOLD detection. The proposed constraint imposes some prior spatial information of active area inside the brain, on the decomposition process. The constraint is built up based on the type of stimulus and available physiological knowledge of the brain performance. The simulation results on both synthetic and real fMRI data show that applying the proposed constraint improves the BOLD detection performance. PMID:22255474

  4. Spatially adaptive multiwavelet representations on unstructured grids with applications to multidimensional computational modeling

    E-print Network

    Castrillón Candás, Julio E. (Julio Enrique)

    2001-01-01

    In this thesis, we develop wavelet surface wavelet representations for complex surfaces, with the goal of demonstrating their potential for 3D scientific and engineering computing applications. Surface wavelets were ...

  5. Spatial Views : Iterative Spatial Programming for Networks of Embedded Systems #

    E-print Network

    Kremer, Ulrich

    Abstract Programming a large network of embedded systems (NES) is an enormous challenge since all for spatially distributed network resources. In Spatial Programming, NES applications appear as simple sequential programs using spatial variables. However, for many NES applications the spatial programming model

  6. A mobile system for quantifying the spatial variability of the surface energy balance: design and application

    NASA Astrophysics Data System (ADS)

    Tasser, Erich; Wohlfahrt, Georg

    2014-05-01

    We present a mobile device for the quantification of the small-scale spatial variability in the surface energy balance components and several auxiliary variables of short-statured canopies. The key element of the mobile device is a hand-held four-component net radiometer for the quantification of net radiation, albedo and infrared surface temperature, which is complemented with measurements of air temperature, wind speed, soil temperature and soil water content. Data are acquired by a battery-powered data logger, which is mounted on a backpack together with the auxiliary sensors. The proposed device was developed to bridge between the spatial scales of satellite/airborne remote sensing and fixed, stationary tower-based measurements with an emphasis on micrometeorological, catchment hydrological and landscape-ecological research questions. The potential of the new device is demonstrated through four selected case studies, which cover the issues of net radiation heterogeneity within the footprint of eddy covariance flux measurements due to (i) land use and (ii) slope and aspect of the underlying surface, (iii) controls on landscape-scale variability in soil temperature and albedo, and (iv) the estimation of evapotranspiration based exclusively on measurements with the mobile device.

  7. Spatial three-dimensional landslide susceptibility mapping tool and its applications

    NASA Astrophysics Data System (ADS)

    Xie, Mowen; Tetsuro, Esaki; Qiu, Cheng; Jia, Lin

    There are three methods of zoning landslide susceptibility: qualitative, statistical methodologies, and geotechnical model. Qualitative approaches are based on the judgment of those conducting the susceptibility or hazard assessment; the statistical approach uses a predictive function or index derived from a combination of weighted factors; and the deterministic, or physically based, models are based on the physical laws of conservation of mass, energy, and momentum. Two-dimensional deterministic models are widely used in the design of civil engineering, and the infinite slope model (one-dimensional) is always employed in the deterministic-model-based landslide hazard mapping. This article presents a new GIS (Geographic Information Systems)-based landslide susceptibility mapping system which can be used to identify the three-dimensional (3-D) landslide bodies from complex topography. All slope-related spatial information (vector or raster dataset) was integrated in the system, by dividing the study area into slope units and assuming the initial slip to be the lower part of an ellipsoid. The 3-D critical slip surface in the 3-D slope stability analysis was located by minimizing the 3-D safety factor using the Monte Carlo random simulation. The failure probability of the landslide was calculated using an approximate method in which effective cohesion, effective friction angle, and 3-D safety factor were assumed to be in normal distribution. A computational program called 3-DSlopeGIS, in which a GIS Developer kit (ArcObjects of ESRI) had been used to fulfill the GIS spatial analysis function and effective data management, has been developed to implement all the calculations of the 3-D slope problem. By using the spatial analysis functions, the data management, and the visualization of GIS for processing the complicated slope-related data, the 3-D slope stability problem is easier to be studied through a friendly visual graphical user interface. The system has been applied for mapping the landslide susceptibility of three examples: the first one for city planning, the second for predicting the possible landslide influence around a past slope disaster, and the third for mapping landslide along a national route. Based on numerous Monte Carlo simulation, the possible critical landslide bodies have been identified, which cannot be carried out by using the traditional slope stability analyses.

  8. Documentation of a spatial data-base management system for monitoring pesticide application in Washington

    USGS Publications Warehouse

    Schurr, K.M.; Cox, S.E.

    1994-01-01

    The Pesticide-Application Data-Base Management System was created as a demonstration project and was tested with data submitted to the Washington State Department of Agriculture by pesticide applicators from a small geographic area. These data were entered into the Department's relational data-base system and uploaded into the system's ARC/INFO files. Locations for pesticide applica- tions are assigned within the Public Land Survey System grids, and ARC/INFO programs in the Pesticide-Application Data-Base Management System can subdivide each survey section into sixteen idealized quarter-quarter sections for display map grids. The system provides data retrieval and geographic information system plotting capabilities from a menu of seven basic retrieval options. Additionally, ARC/INFO coverages can be created from the retrieved data when required for particular applications. The Pesticide-Application Data-Base Management System, or the general principles used in the system, could be adapted to other applica- tions or to other states.

  9. Mapping genetic diversity of cherimoya (Annona cherimola Mill.): application of spatial analysis for conservation and use of plant genetic resources.

    PubMed

    Zonneveld, Maarten van; Scheldeman, Xavier; Escribano, Pilar; Viruel, María A; Van Damme, Patrick; Garcia, Willman; Tapia, César; Romero, José; Sigueñas, Manuel; Hormaza, José I

    2012-01-01

    There is a growing call for inventories that evaluate geographic patterns in diversity of plant genetic resources maintained on farm and in species' natural populations in order to enhance their use and conservation. Such evaluations are relevant for useful tropical and subtropical tree species, as many of these species are still undomesticated, or in incipient stages of domestication and local populations can offer yet-unknown traits of high value to further domestication. For many outcrossing species, such as most trees, inbreeding depression can be an issue, and genetic diversity is important to sustain local production. Diversity is also crucial for species to adapt to environmental changes. This paper explores the possibilities of incorporating molecular marker data into Geographic Information Systems (GIS) to allow visualization and better understanding of spatial patterns of genetic diversity as a key input to optimize conservation and use of plant genetic resources, based on a case study of cherimoya (Annona cherimola Mill.), a Neotropical fruit tree species. We present spatial analyses to (1) improve the understanding of spatial distribution of genetic diversity of cherimoya natural stands and cultivated trees in Ecuador, Bolivia and Peru based on microsatellite molecular markers (SSRs); and (2) formulate optimal conservation strategies by revealing priority areas for in situ conservation, and identifying existing diversity gaps in ex situ collections. We found high levels of allelic richness, locally common alleles and expected heterozygosity in cherimoya's putative centre of origin, southern Ecuador and northern Peru, whereas levels of diversity in southern Peru and especially in Bolivia were significantly lower. The application of GIS on a large microsatellite dataset allows a more detailed prioritization of areas for in situ conservation and targeted collection across the Andean distribution range of cherimoya than previous studies could do, i.e. at province and department level in Ecuador and Peru, respectively. PMID:22253801

  10. Mapping Genetic Diversity of Cherimoya (Annona cherimola Mill.): Application of Spatial Analysis for Conservation and Use of Plant Genetic Resources

    PubMed Central

    van Zonneveld, Maarten; Scheldeman, Xavier; Escribano, Pilar; Viruel, María A.; Van Damme, Patrick; Garcia, Willman; Tapia, César; Romero, José; Sigueñas, Manuel; Hormaza, José I.

    2012-01-01

    There is a growing call for inventories that evaluate geographic patterns in diversity of plant genetic resources maintained on farm and in species' natural populations in order to enhance their use and conservation. Such evaluations are relevant for useful tropical and subtropical tree species, as many of these species are still undomesticated, or in incipient stages of domestication and local populations can offer yet-unknown traits of high value to further domestication. For many outcrossing species, such as most trees, inbreeding depression can be an issue, and genetic diversity is important to sustain local production. Diversity is also crucial for species to adapt to environmental changes. This paper explores the possibilities of incorporating molecular marker data into Geographic Information Systems (GIS) to allow visualization and better understanding of spatial patterns of genetic diversity as a key input to optimize conservation and use of plant genetic resources, based on a case study of cherimoya (Annona cherimola Mill.), a Neotropical fruit tree species. We present spatial analyses to (1) improve the understanding of spatial distribution of genetic diversity of cherimoya natural stands and cultivated trees in Ecuador, Bolivia and Peru based on microsatellite molecular markers (SSRs); and (2) formulate optimal conservation strategies by revealing priority areas for in situ conservation, and identifying existing diversity gaps in ex situ collections. We found high levels of allelic richness, locally common alleles and expected heterozygosity in cherimoya's putative centre of origin, southern Ecuador and northern Peru, whereas levels of diversity in southern Peru and especially in Bolivia were significantly lower. The application of GIS on a large microsatellite dataset allows a more detailed prioritization of areas for in situ conservation and targeted collection across the Andean distribution range of cherimoya than previous studies could do, i.e. at province and department level in Ecuador and Peru, respectively. PMID:22253801

  11. Development of a web GIS application for emissions inventory spatial allocation based on open source software tools

    NASA Astrophysics Data System (ADS)

    Gkatzoflias, Dimitrios; Mellios, Giorgos; Samaras, Zissis

    2013-03-01

    Combining emission inventory methods and geographic information systems (GIS) remains a key issue for environmental modelling and management purposes. This paper examines the development of a web GIS application as part of an emission inventory system that produces maps and files with spatial allocated emissions in a grid format. The study is not confined in the maps produced but also presents the features and capabilities of a web application that can be used by every user even without any prior knowledge of the GIS field. The development of the application was based on open source software tools such as MapServer for the GIS functions, PostgreSQL and PostGIS for the data management and HTML, PHP and JavaScript as programming languages. In addition, background processes are used in an innovative manner to handle the time consuming and computational costly procedures of the application. Furthermore, a web map service was created to provide maps to other clients such as the Google Maps API v3 that is used as part of the user interface. The output of the application includes maps in vector and raster format, maps with temporal resolution on daily and hourly basis, grid files that can be used by air quality management systems and grid files consistent with the European Monitoring and Evaluation Programme Grid. Although the system was developed and validated for the Republic of Cyprus covering a remarkable wide range of pollutant and emissions sources, it can be easily customized for use in other countries or smaller areas, as long as geospatial and activity data are available.

  12. Wave optics simulation of spatially partially coherent beams: Applications to free space laser communications

    Microsoft Academic Search

    Xifeng Xiao

    2008-01-01

    One of the main drawbacks that prevent the extensive application of free space laser communications is the atmospheric turbulence through which the beam must propagate. For the past four decades, much attention has been devoted to finding different methods to overcome this difficulty. A partially coherent beam (PCB) has been recognized as an effective approach to improve the performance of

  13. Bayesian Models for Spatial Extremes Application to inferring high values of

    E-print Network

    Gilleland, Eric

    ): · carbon monoxide (CO), · lead (Pb), · nitrogen dioxide (NO2), · ground-level Ozone (O3), · particulate matter (PM) and · sulfur dioxide (SO2) #12;Background to Ozone Application: New NAAQS for ozone ­ models block maxima · GPD ­ models threshold exceedances #12;Generalized Pareto Distribution [Pickands

  14. A novel capacitance sensor principle applicable for spatially resolving downhole measurements

    Microsoft Academic Search

    Gert Holler; Thomas Thurner; Hubert Zangl; Georg Brasseur

    2002-01-01

    The paper presents a new approach for the design of capacitive sensors capable of determining the permittivity distribution within a pipe. Due to the robust design and the simple geometry of the sensor, the proposed principle is applicable for downhole measurement systems even when operated at extreme environmental conditions. Results of fill level and water fraction measurements at ambient conditions

  15. Retrieval Of Daily Evapotranspiration From Remote Sensing Images Of High And Low Spatial Resolution. Application To The Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Gómez, M.; Sobrino, J. A.; Olioso, A.; Jiménez-Muñoz, J. C.

    2006-08-01

    Evapotranspiration is an important parameter to optimize water use, especially in non-irrigated and arid or semiarid rangelands. A simplified method to derive the daily evapotranspiration using remote sensing images of high and low spatial resolution is presented in this paper. The method is based on the evaporative concept employed in the S-SEBI (Simplified Surface Energy Balance Index) model, and it is applicable under the assumption of constant atmospheric conditions and sufficient wet and dry pixels over the image. The method, applied to DAIS and NOAA-AVHRR images, has been tested using ET values measured over the agricultural area of Barrax (Castilla-La Mancha, Spain), and an accuracy for the daily evapotranspiration lower than 1 mmd-1 has been obtained..

  16. An operational MODIS aerosol retrieval algorithm at high spatial resolution, and its application over a complex urban region

    NASA Astrophysics Data System (ADS)

    Wong, Man Sing; Nichol, Janet E.; Lee, Kwon Ho

    2011-03-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well-researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, an aerosol retrieval algorithm using the MODIS 500-m resolution bands is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectances by decomposing the top-of-atmosphere reflectances from surface reflectances and Rayleigh path reflectances. For the determination of surface reflectances, a Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. For conversion of aerosol reflectance to aerosol optical thickness (AOT), comprehensive Look Up Tables specific to the local region are constructed, which consider aerosol properties and sun-viewing geometry in the radiative transfer calculations. Four local aerosol types, namely coastal urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on 3 years of AERONET measurements in Hong Kong. The resulting 500 m AOT images were found to be highly correlated with ground measurements from the AERONET (r2 = 0.767) and Microtops II sunphotometers (r2 = 0.760) in Hong Kong. This study further demonstrates the application of the fine resolution AOT images for monitoring inter-urban and intra-urban aerosol distributions and the influence of trans-boundary flows. These applications include characterization of spatial patterns of AOT within the city, and detection of regional biomass burning sources.

  17. Spatial deconvolution of spectropolarimetric data: an application to quiet Sun magnetic elements

    NASA Astrophysics Data System (ADS)

    Quintero Noda, C.; Asensio Ramos, A.; Orozco Suárez, D.; Ruiz Cobo, B.

    2015-07-01

    Context. One of the difficulties in extracting reliable information about the thermodynamical and magnetic properties of solar plasmas from spectropolarimetric observations is the presence of light dispersed inside the instruments, known as stray light. Aims: We aim to analyze quiet Sun observations after the spatial deconvolution of the data. We examine the validity of the deconvolution process with noisy data as we analyze the physical properties of quiet Sun magnetic elements. Methods: We used a regularization method that decouples the Stokes inversion from the deconvolution process, so that large maps can be quickly inverted without much additional computational burden. We applied the method on Hinode quiet Sun spectropolarimetric data. We examined the spatial and polarimetric properties of the deconvolved profiles, comparing them with the original data. After that, we inverted the Stokes profiles using the Stokes Inversion based on Response functions (SIR) code, which allow us to obtain the optical depth dependence of the atmospheric physical parameters. Results: The deconvolution process increases the contrast of continuum images and makes the magnetic structures sharper. The deconvolved Stokes I profiles reveal the presence of the Zeeman splitting while the Stokes V profiles significantly change their amplitude. The area and amplitude asymmetries of these profiles increase in absolute value after the deconvolution process. We inverted the original Stokes profiles from a magnetic element and found that the magnetic field intensity reproduces the overall behavior of theoretical magnetic flux tubes, that is, the magnetic field lines are vertical in the center of the structure and start to fan when we move far away from the center of the magnetic element. The magnetic field vector inferred from the deconvolved Stokes profiles also mimic a magnetic flux tube but in this case we found stronger field strengths and the gradients along the line-of-sight are larger for the magnetic field intensity and for its inclination. Moreover, the discontinuity between the magnetic and non magnetic environment in the flux tube gets sharper. Conclusions: The deconvolution process used in this paper reveals information that the smearing induced by the point spread function (PSF) of the telescope hides. Additionally, the deconvolution is done with a low computational load, making it appealing for its use on the analysis of large data sets. A copy of the IDL code is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/579/A3

  18. Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping

    SciTech Connect

    Rossow, Molly; Gratton, Enrico [Biomedical Engineering Department, University of California Irvine, Irvine, California (United States); Mantulin, William M. [Beckman Laser Institute, University of California Irvine, Irvine, California (United States)

    2009-04-19

    It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles--such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

  19. Application of an extended equalization-cancellation model to speech intelligibility with spatially distributed maskers

    PubMed Central

    Wan, Rui; Durlach, Nathaniel I.; Colburn, H. Steven

    2010-01-01

    An extended version of the equalization-cancellation (EC) model of binaural processing is described and applied to speech intelligibility tasks in the presence of multiple maskers. The model incorporates time-varying jitters, both in time and amplitude, and implements the equalization and cancellation operations in each frequency band independently. The model is consistent with the original EC model in predicting tone-detection performance for a large set of configurations. When the model is applied to speech, the speech intelligibility index is used to predict speech intelligibility performance in a variety of conditions. Specific conditions addressed include different types of maskers, different numbers of maskers, and different spatial locations of maskers. Model predictions are compared with empirical measurements reported by Hawley et al. [J. Acoust. Soc. Am. 115, 833–843 (2004)] and by Marrone et al. [J. Acoust. Soc. Am. 124, 1146–1158 (2008)]. The model succeeds in predicting speech intelligibility performance when maskers are speech-shaped noise or broadband-modulated speech-shaped noise but fails when the maskers are speech or reversed speech. PMID:21218900

  20. Spatial computation

    Microsoft Academic Search

    Mihai Budiu; Girish Venkataramani; Tiberiu Chelcea; Seth Copen Goldstein

    2004-01-01

    This paper describes a computer architecture, Spatial Computation (SC), which is based on the translation of high-level language programs directly into hardware structures. SC program implementations are completely distributed, with no centralized control. SC circuits are optimized for wires at the expense of computation units.In this paper we investigate a particular implementation of SC: ASH (Application-Specific Hardware). Under the assumption

  1. The Application of Spatial Signature Analysis to Electrical Test Data: Validation Study

    SciTech Connect

    Gleason, S.S.; Karnowski, T.P.; Lakhani, F.; Tobin, K.W.

    1999-03-15

    This paper presents the results of the Spatial Signature Analysis (SSA) Electrical-test (e-test) validation study that was conducted between February and June, 1998. SSA is an automated procedure developed by researchers at the Oak Ridge National Laboratory to address the issue of intelligent data reduction while providing feedback on current manufacturing processes. SSA was initially developed to automate the analysis of optical defect data. Optical defects can form groups, or clusters, which may have a distinct shape. These patterns can reveal information about the manufacturing process. Optical defect SSA uses image processing algorithms and a classifier system to interpret and identify these patterns, or signatures. SSA has been extended to analyze and interpret electrical test data. The algorithms used for optical defect SSA have been adapted and applied to e-test binmaps. An image of the binmap is created, and features such as geometric and invariant moments are extracted and presented to a pair-wise, fuzzy, k-NN classifier. The classifier itself was prepared by manually training, which consists of storing example signatures of interest in a library, then executing an automated process which treats the examples as prototype signatures. The training process includes a procedure for automatically determining which features are most relevant to each class. The evaluation was performed by installing the SSA software as a batch process at three SEMATECH member company sites. Feedback from member company representatives was incorporated and classifiers were built to automatically assign labels to the binmap signatures. The three sites produced memory devices (DRAM) and microprocessors in a mature process fabrication environment. For all of these products, 5,620 signatures that encompassed approximately 552 wafers were human-classified and analyzed. The performance of the SSA E-test system indicates that the approach was successful in reliably classifying binmap signatures in a manner similar to the human expert.

  2. Spatial Frequency Domain Imaging: Applications in Preclinical Models of Alzheimer's Disease

    NASA Astrophysics Data System (ADS)

    Lin, Alexander Justin

    A clinical challenge in Alzheimer's disease (AD) is diagnosing and treating patients earlier, before symptoms of cognitive dysfunction occur. A good screening test would be sensitive to the AD brain pathology, safe, and cost-effective. Diffuse optical imaging, which measures how non-ionizing light is absorbed and scattered in tissue, may fulfill these three parameters. We imaged the brains of transgenic AD mouse models in vivo with a quantitative, camera-based, diffuse optical imaging technology called spatial frequency domain imaging (SFDI) to characterize near-infrared (650-970nm) optical biomarkers of AD. Compared to age-matched control mice, we found a decrease in light absorption --- due to lower oxygenated and total hemoglobin concentrations in the brain --- correlating to decreased blood vessel volume and density in histology. Light scattering also increased in AD mice, correlating to brain structural changes caused by neuron loss and activation of inflammatory cells. Furthermore, inhaled gas challenges revealed brain vascular function was diminished. To investigate how AD affects the small changes in blood perfusion caused by increased brain activity, we built a new SFDI system from a commercial light-emitting diode microprojector and off-the-shelf optical components and cameras to measure optical properties in the visible range (460-632nm). Our measurements showed a reduced amplitude and duration of blood vessel dilation to increased brain activity in the AD mice. Altogether, this work increased our understanding of AD pathogenesis, explored optical biomarkers of AD, and improved technology access to other research labs. These results and technologies can further be used to facilitate longitudinal drug therapy trials in mice and provide a roadmap to diffuse optical spectroscopy studies in humans.

  3. Modeling and application of soil moisture at varying spatial scales with parameter scaling 

    E-print Network

    Das, Narendra Narayan

    2009-05-15

    will be launched in 2009. It will monitor soil moisture, ocean salinity, the water content in vegetation, and the snow and ice cover by using a passive microwave interferometer MIRAS i.e., Microwave Imaging Radiometer using Aperture Synthesis. MIRAS will operate... Efendiev, and Dr. Robert D. Hetland for their guidance and support during my research work. I also want to extend my gratitude to Dr. Eni Njoku for introducing me to the concept and applications of microwave remote sensing of soil moisture and providing...

  4. Spatial scale invariance of aggregated dynamics - Application to crops cycle observed from space

    NASA Astrophysics Data System (ADS)

    Mangiarotti, S.; Le Jean, F.

    2014-12-01

    Observational data is always associated to specific time and space scales. When the observed area of study is homogeneous, the same dynamics can be expected at different observed scales. It is generally not the case. This is a common obstacle when comparing data or products of different resolution. This question is investigated here considering the cycles of rainfed crops observed from space in semi-arid regions. In such context, the rainfed crops are coupled to the climatic dynamics in a synchronized way, the observational signal can thus be seen as an aggregation of phase synchronized dynamics. In the first part of this work, a case study is implemented. Rössler chaotic systems are used for this purpose as elementary oscillators relating to homogeneous behavior. The 'observational' signal is obtained by aggregating additively the signals of several elementary chaotic systems. Analytically, it is found that the aggregated signal can be approximated by the Rössler system itself but with some parameterization changes. This result can be generalized to any system for which a canonical approximation is possible. Using the global modeling technique [1], this theoretical result is then illustrated practically, by showing that an approximation of the Rössler dynamics can be retrieved, without any a priori knowledge, from the aggregated signal. In the second part, the cycle of cereal crops observed from space in semi-arid conditions is investigated from real observational data (the GIMMS product of Normalized Difference Vegetation Index [2] is used for this purpose). A low-dimensional chaotic model could recently be obtained from a spatially aggregated signal which presents properties never observed from real data before: a toroidal and weakly dissipative dynamics [3]. These unusual properties are then retrieved at various places and scales. [1] Mangiarotti S., Coudret R., Drapeau L. & Jarlan L., 2012. Polynomial search and Global modelling: two algorithms for modeling chaos. Physical Review E, 86(4), 046205. [2] Tucker C. J., Pinzon J. E., Brown M. E., Slayback D. A., Pak E. W., Mahoney R., Vermote E. F. & Saleous N. E., 2005. Int. J. Remote Sensing, 26, 4485. [3] Mangiarotti S., Drapeau L. & Letellier C., 2014. Two chaotic global models for cereal crops cycles observed from satellite in Northern Morocco. Chaos, 24, 023130.

  5. Optimising the application of multiple-capture traps for invasive species management using spatial simulation.

    PubMed

    Warburton, Bruce; Gormley, Andrew M

    2015-01-01

    Internationally, invasive vertebrate species pose a significant threat to biodiversity, agricultural production and human health. To manage these species a wide range of tools, including traps, are used. In New Zealand, brushtail possums (Trichosurus vulpecula), stoats (Mustela ermine), and ship rats (Rattus rattus) are invasive and there is an ongoing demand for cost-effective non-toxic methods for controlling these pests. Recently, traps with multiple-capture capability have been developed which, because they do not require regular operator-checking, are purported to be more cost-effective than traditional single-capture traps. However, when pest populations are being maintained at low densities (as is typical of orchestrated pest management programmes) it remains uncertain if it is more cost-effective to use fewer multiple-capture traps or more single-capture traps. To address this uncertainty, we used an individual-based spatially explicit modelling approach to determine the likely maximum animal-captures per trap, given stated pest densities and defined times traps are left between checks. In the simulation, single- or multiple-capture traps were spaced according to best practice pest-control guidelines. For possums with maintenance densities set at the lowest level (i.e. 0.5/ha), 98% of all simulated possums were captured with only a single capacity trap set at each site. When possum density was increased to moderate levels of 3/ha, having a capacity of three captures per trap caught 97% of all simulated possums. Results were similar for stoats, although only two potential captures per site were sufficient to capture 99% of simulated stoats. For rats, which were simulated at their typically higher densities, even a six-capture capacity per trap site only resulted in 80% kill. Depending on target species, prevailing density and extent of immigration, the most cost-effective strategy for pest control in New Zealand might be to deploy several single-capture traps rather than investing in fewer, but more expense, multiple-capture traps. PMID:25782018

  6. Optimising the Application of Multiple-Capture Traps for Invasive Species Management Using Spatial Simulation

    PubMed Central

    Warburton, Bruce; Gormley, Andrew M.

    2015-01-01

    Internationally, invasive vertebrate species pose a significant threat to biodiversity, agricultural production and human health. To manage these species a wide range of tools, including traps, are used. In New Zealand, brushtail possums (Trichosurus vulpecula), stoats (Mustela ermine), and ship rats (Rattus rattus) are invasive and there is an ongoing demand for cost-effective non-toxic methods for controlling these pests. Recently, traps with multiple-capture capability have been developed which, because they do not require regular operator-checking, are purported to be more cost-effective than traditional single-capture traps. However, when pest populations are being maintained at low densities (as is typical of orchestrated pest management programmes) it remains uncertain if it is more cost-effective to use fewer multiple-capture traps or more single-capture traps. To address this uncertainty, we used an individual-based spatially explicit modelling approach to determine the likely maximum animal-captures per trap, given stated pest densities and defined times traps are left between checks. In the simulation, single- or multiple-capture traps were spaced according to best practice pest-control guidelines. For possums with maintenance densities set at the lowest level (i.e. 0.5/ha), 98% of all simulated possums were captured with only a single capacity trap set at each site. When possum density was increased to moderate levels of 3/ha, having a capacity of three captures per trap caught 97% of all simulated possums. Results were similar for stoats, although only two potential captures per site were sufficient to capture 99% of simulated stoats. For rats, which were simulated at their typically higher densities, even a six-capture capacity per trap site only resulted in 80% kill. Depending on target species, prevailing density and extent of immigration, the most cost-effective strategy for pest control in New Zealand might be to deploy several single-capture traps rather than investing in fewer, but more expense, multiple-capture traps. PMID:25782018

  7. Quantifying landscape pattern in the Ouachita National Forest: an ecological application of GIS-based spatial analysis and modeling 

    E-print Network

    Meyer, Delayne Marie

    1998-01-01

    major alterations in spatial pattern. Because of the importance of effects of spatial pattern and configuration on ecological processes, many land and resource managers are beginning to realize the need to develop ways to detect and quantify pattern...

  8. Development and application of the spatially explicit load enrichment calculation tool (select) to determine potential E. coli loads in watersheds

    E-print Network

    Riebschleager, Kendra Jean

    2009-05-15

    According to the USEPA National Section 303(d) List Fact Sheet, bacterial pathogens are the leading cause of water quality impairments in Texas. The automated Spatially Explicit Load Enrichment Calculation Tool (SELECT) uses spatially variable...

  9. Spatial Knowledge Spatial representation

    E-print Network

    Pillow, Jonathan

    1 Spatial Knowledge · Spatial representation · Mental maps · Large-scale space · Small-scale space) ­ Cognitive geography · Maps of large-scale space ­ What is our sense of the locations of items in the world? Large-scale space · Which is further north: ­ Austin, TX or Chicago, IL? ­ Portland, OR or Portland, ME

  10. The effect of application technique ont he temporal and spatial distribution of neonicotinoid insecticides in greenhouse zinnia and impact on aphid populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse trials were designed to evaluate the effect the application technique would have on temporal and spatial movement of neonicotinoid insecticides imidacloprid and thiamethoxam through plant tissue. Mature Zinnia elegans plants were treated by either a soil drench of neonicotinoid insectici...

  11. DotAGWA: A case study in web-based architectures for connecting surface water models to spatially enabled web applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Automated Geospatial Watershed Assessment (AGWA) tool is a desktop application that uses widely available standardized spatial datasets to derive inputs for multi-scale hydrologic models (Miller et al., 2007). The required data sets include topography (DEM data), soils, climate, and land-cover ...

  12. An application of spatially constrained inversion using FD Helicopter EM data to characterise spatial variations in groundwater salinity across the floodplains of the Murray River in South-eastern Australia

    NASA Astrophysics Data System (ADS)

    Munday, T. J.; Viezzoli, A.; Fitzpatrick, A.

    2008-12-01

    The floodplains of the Murray River, situated in the southeast of Australia, have become extensively salinised, related in part to the discharge of naturally saline groundwater linked to increased recharge from land clearing and irrigation adjacent to the river. This problem has been compounded by extended drought conditions that prevail across the Murray Basin, resulting in increase in the accumulation and concentration of salt within the floodplain soils and an increase in salt loads to the river. Consequently in many floodplain areas along the Murray, the native riparian vegetation communities are in severe decline and Eucalyptus largiflorens (Black Box) and E. camaldulensis (Red Gum) communities are being significantly affected. A range management strategies are being employed to manage these issues, the manipulation of river flows to enhance biodiversity values (ie restore vegetation health) and the development of a hydro-dynamic models to better understand surface flows and the role of soils and elevation in floodplain vegetation health. Integral to these strategies is the acquisition of detailed spatial data on the distribution of salinity in floodplain soils and groundwater, thereby indicating patterns of groundwater evapotranspiration and baseflow across these areas. Hydrogeophysical data from electrical (inductive) methods have considerable potential to provide such data. We present an application of the Spatially Constrained Inversion (SCI) of RESOLVE FDHEM (airborne EM) data for defining spatial patterns of salinisation in the sunraysia irrigation area located in the lower Murray Basin of South Australia. Spatially Constrained Inversion uses Delaunay triangulation to set three dimensional constraints between neighbouring soundings, taking advantage of the spatial coherency that may be present in the data set. Conductivity information for individual soundings is linked through the spatial constraints, from well determined parameters to locally poorly determined parameters. For the survey presented here, SCI generated maps detail the spatial variability of floodplain salinisation, the extent of floodplain sediments influenced by lateral recharge and flushing along stretches of the Murray River, and the variability quality of groundwater in deeper semi-confined aquifers. Available borehole and other ancillary information, such as vegetation density and health patterns, match the observed conductivity variations seen in the SCI results, even at the very near surface (~2m depth). The SCI provide more accurate and spatially consistent results compared with those from single site inversions. We also compare the SCI inversion against that generated from a Holistic inversion of the same data set. The results compare well in the near surface, although the observed responses at depth for the latter depart from that expected, with more resistive responses being defined.

  13. The application of quaternions and other spatial representations to the reconstruction of re-entry vehicle motion.

    SciTech Connect

    De Sapio, Vincent

    2010-09-01

    The analysis of spacecraft kinematics and dynamics requires an efficient scheme for spatial representation. While the representation of displacement in three dimensional Euclidean space is straightforward, orientation in three dimensions poses particular challenges. The unit quaternion provides an approach that mitigates many of the problems intrinsic in other representation approaches, including the ill-conditioning that arises from computing many successive rotations. This report focuses on the computational utility of unit quaternions and their application to the reconstruction of re-entry vehicle (RV) motion history from sensor data. To this end they will be used in conjunction with other kinematic and data processing techniques. We will present a numerical implementation for the reconstruction of RV motion solely from gyroscope and accelerometer data. This will make use of unit quaternions due to their numerical efficacy in dealing with the composition of many incremental rotations over a time series. In addition to signal processing and data conditioning procedures, algorithms for numerical quaternion-based integration of gyroscope data will be addressed, as well as accelerometer triangulation and integration to yield RV trajectory. Actual processed flight data will be presented to demonstrate the implementation of these methods.

  14. Spatial distribution analysis of strontium in human teeth by laser-induced breakdown spectroscopy: application to diagnosis of seawater drowning.

    PubMed

    Fortes, Francisco J; Perez-Carceles, Maria D; Sibon, Agustin; Luna, Aurelio; Laserna, J Javier

    2015-07-01

    The diagnosis of drowning can be extremely difficult, especially when the typical morphological signs of drowning are not present, or when the body is in an advanced stage of putrefaction. The main aim of this work is to demonstrate the applicability of laser-induced breakdown spectroscopy (LIBS) to the diagnosis of seawater drowning. Ten teeth samples were selected from eight medico-legal autopsies. A Nd:YAG laser operating at its fundamental wavelength (1,064 nm) was used to generate microplasmas at the sample surface. Strontium (Sr) concentration in tooth samples has been found to be a key factor for the diagnosis of seawater drowning. Spectral differences between the dentin and the enamel were observed. Greater Sr abundance was located in the dentin, with relative standard deviations in the range of 30 to 35 %. In addition, chemical images were generated to study the spatial distribution of Sr along the piece. In all cases, Sr content was higher when the cause of the individual death was drowning. A blind experiment was performed to exclude the possibility that the increase of Sr is due to passive diffusion in the blood. The detection of Sr as well as the determination of its distribution by LIBS in dentin seems to be a promising complementary tool for the diagnosis of death by seawater drowning. PMID:25432861

  15. Enhancing a Low-Cost Virtual Reality Application through Constructivist Approach: The Case of Spatial Training of Middle Graders

    ERIC Educational Resources Information Center

    Samsudin, Khairulanuar; Rafi, Ahmad; Mohamad Ali, Ahmad Zamzuri; Abd. Rashid, Nazre

    2014-01-01

    The aim of this study is to develop and to test a low-cost virtual reality spatial trainer in terms of its effectiveness in spatial training. The researchers adopted three features deriving from the constructivist perspective to guide the design of the trainer, namely interaction, instruction, and support. The no control pre test post test…

  16. To appear in: 2006 International Conference on Computer Vision Theory and Applications, Setubal, Portugal. SPATIAL STATISTICS OF TEXTONS

    E-print Network

    Ribeiro, Eraldo

    classification, pollen, spatial statistics. Abstract: Texture classification is one of the most studied learned texture elements. This is accomplished by calculating spatial co-occurrence statistics on the maps as well as natural textures from a tropical pollen database. We also present a comparison with a state

  17. A LOCAL CORRELATION APPROACH FOR THE FUSION OF REMOTE SENSING DATA WITH DIFFERENT SPATIAL RESOLUTIONS IN FORESTRY APPLICATIONS

    Microsoft Academic Search

    J. Hill; C. Diemer

    1999-01-01

    Until now, satellite data are only of limited use to Mid-European forest management. A major limitation is the low spatial reso lution of the commonly available satellite sensors. In this paper, we present a specific data fusion approach (local correlation model ling) which can be used to produce multispectral images with high spatial resolution based on panchromatic reference channels. Such

  18. Spatially distributed flood forecasting in flash flood prone areas: Application to road network supervision in Southern France

    NASA Astrophysics Data System (ADS)

    Naulin, J.-P.; Payrastre, O.; Gaume, E.

    2013-04-01

    SummaryAccurate flood forecasts are critical to an efficient flood event management strategy. Until now, hydro-meteorological forecasts have mainly been used to establish early-warnings in France (meteorological and flood vigilance maps) or over the world (flash-flood guidances). These forecasts are typically limited either to the main streams covered by the flood forecasting services or to watersheds with specific assets like check dams, which in most cases are well gauged river sections, thus leaving aside large parts of the territory. This paper presents a distributed hydro-meteorological forecasting approach, which makes use of the high spatial and temporal resolution rainfall estimates that are now available, to provide information at ungauged sites. The proposed system intended to detect road inundation risks had initially been developed and tested in areas of limited size. This paper presents the extension of such a system to an entire region (i.e. the Gard region in Southern France), including over 2000 crossing points between rivers and roads and its validation with respect to a large data set of actual reported road inundations observed during recent flash flood events. These initial validation results appear to be most promising. The eventual proposed tool would provide the necessary information for flood event management services to identify the areas at risk and adopt appropriate safety and rescue measures: i.e. pre-positioning of rescue equipment, interruption of the traffic on the exposed roads and determination of safe access or evacuation routes. Moreover, beyond the specific application to the supervision of a road network, the research undertaken herein also provides results for the performance of hydro-meteorological forecasts on ungauged headwaters.

  19. Using spatially distributed parameters and multi-response objective functions to solve parameterization of complex applications of semi-distributed hydrological models

    Microsoft Academic Search

    Rafael Marcé; Carlos E. Ruiz; Joan Armengol

    2008-01-01

    Application of semi-distributed hydrological models to large, heterogeneous watersheds deals with several problems. On one hand, the spatial and temporal variability in catchment features should be adequately represented in the model parameterization, while maintaining the model complexity in an acceptable level to take advantage of state-of-the-art calibration techniques. On the other hand, model complexity enhances uncertainty in adjusted model parameter

  20. Testing the importance of spatial configuration of winter habitat for woodland caribou: An application of graph theory

    E-print Network

    Fortin, Marie Josee

    T Conservation of remaining woodland caribou (Rangifer tarandus caribou) populations requires land management. Ó 2006 Elsevier Ltd. All rights reserved. 1. Introduction Woodland caribou (Rangifer tarandusTesting the importance of spatial configuration of winter habitat for woodland caribou

  1. Spatial and temporal synthesized probability gain for middle and long-term earthquake forecast and its preliminary application

    Microsoft Academic Search

    Xiao-Qing Wang; Zheng-Xiang Fu; Li-Ren Zhang; Sheng-Ping Su; Xiang Ding

    2000-01-01

    The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the\\u000a evaluation of forecast efficiency (R-values) of various forecast methods are introduced in this paper. The R-value method, developed by Xu (1989), is further developed here, and can be applied to more complicated cases. Probability\\u000a gains in spatial and\\/or temporal domains and the

  2. Analysis of the spatial variation in the parameters of the SWAT model with application in Flanders,Northern Belgium Hydrology and Earth System Sciences, 8(5), 931939 (2004) EGU

    E-print Network

    Boyer, Edmond

    2004-01-01

    Analysis of the spatial variation in the parameters of the SWAT model with application in Flanders variation in the parameters of the SWAT model with application in Flanders, Northern Belgium Griet other catchments or time periods. It has been demonstrated that for applications of the SWAT in Northern

  3. Relative impacts of the fragmentation and spatial structure of habitats on freshwater fish distributions: application on French watersheds (Invited)

    NASA Astrophysics Data System (ADS)

    Le Pichon, C.; Belliard, J.; Talès, E.; Gorges, G.; Clément, F.

    2009-12-01

    Most of the rivers of the Ile de France region, intimately linked with the megalopolis of Paris, are severely altered and freshwater fishes are exposed to habitat alteration, reduced connectivity and pollution. Several species thus present fragmented distributions and decreasing densities. In this context, the European Water Framework Directive (2000) has goals of hydrosystems rehabilitation and no further damage. In particular, the preservation and restoration of ecological connectivity of river networks is a key element for fish populations. These goals require the identification of natural and anthropological factors which influence the spatial distribution of species. We have proposed a riverscape approach, based on landscape ecology concepts, combined with a set of spatial analysis methods to assess the multiscale relationships between the spatial pattern of fish habitats and processes depending on fish movements. In particular, we used this approach to test the relative roles of spatial arrangement of fish habitats and the presence of physical barriers in explaining fish spatial distributions in a small rural watershed (106 km2). We performed a spatially continuous analysis of fish-habitat relationships. Fish habitats and physical barriers were mapped along the river network (33 km) with a GPS and imported into a GIS. In parallel, a longitudinal electrofishing survey of the distribution and abundance of fishes was made using a point abundance sampling scheme. Longitudinal arrangement of fish habitats were evaluated using spatial analysis methods: patch/distance metrics and moving window analysis. Explanatory models were developed to test the relative contribution of local environmental variables and spatial context in explaining fish presence. We have recorded about 100 physical barriers, on average one every 330 meters; most artificial barriers were road pipe culverts, falls associated with ponds and sluice gates. Contrasted fish communities and densities were observed in the different areas of the watershed, related to various land use (riparian forest or agriculture). The first results of fish-habitat association analysis on a 5 km stream are that longitudinal distribution of fish species was mainly impacted by falls associated with ponds. The impact was both due to the barrier effect and to the modification of aquatic habitats. Abundance distribution of Salmo trutta and Cottus gobio was particularly affected. Spatially continuous analysis of fish-habitat relationships allowed us to identify the relative impacts of habitat alteration and presence of physical barriers to fish movements. These techniques could help prioritize preservation and restoration policies in human-impacted watersheds, in particular, identifying the key physical barriers to remove.

  4. Analysis of the spatial climate structure from a viticultural perspective. Application to determine viticulture suitability and zonification in Extremadura (Spain)

    NASA Astrophysics Data System (ADS)

    Rebollo, Francisco J.; Moral, Francisco J.; Paniagua, Luís L.; García, Abelardo

    2014-05-01

    The basis for assessing the suitability for viticulture in wine regions is an accurate depiction of the temperature spatial distribution. Thus, using data for a long time internal (1980-2011) and from 117 meteorological stations, four bioclimatic indices were calculated and their spatial distribution patterns were mapped using a multivariate method, the regression-kriging technique. It was obtained that the spatial variability of climate within Extremaduran natural regions (NRs) is significant. Although the warmer conditions predominate in Extremadura, some NRs have part of their territory by up to eight climate classes; this information enables a better understanding of the viticulture suitability within each NR and delineating homogeneous zones. Finally, comparisons of Extremaduran NRs with others worlwide were conducted, which should be taken into account to select varieties and assess the possibilities of producing new wines.

  5. Application of a spatially referenced water quality model to predict E. coli flux in two Texas river basins

    E-print Network

    , Deepti

    2009-05-15

    analyzed. The effect of uncertainty in the monitored records on SPARROW application was discussed. The application of SPARROW and genetic algorithm were explored to design a monitoring network for the study area. The results of this study show that SPARROW...

  6. Continuous-time Monte Carlo and spatial ordering in driven lattice gases: Application to driven vortices in periodic superconducting networks

    E-print Network

    Teitel, Stephen L.

    dynamical rules are introduced to investigate driven diffusive steady states far from equilibrium on which dynamical rule is used. We show that the commonly used driven diffusive Metropolis Monte Carlo is then developed, which results in spatially ordered driven states at low temperature in finite sized systems. We

  7. CCS scenarios optimization by spatial multi-criteria analysis: Application to multiple source sink matching in Hebei province

    Microsoft Academic Search

    Wenying Chen; Yves-Michel Le Nindre; Ruina Xu; Delphine Allier; Fei Teng; Kim Domptail; Xing Xiang; Laura Guillon; Jiyong Chen; Lingyan Huang; Rongshu Zeng

    2010-01-01

    A method, based on spatial analysis of the different criteria to be taken into consideration for building scenarios of CO2 capture and storage (CCS), has been developed and applied to real case studies in the Hebei province. Totally 88 point sources (42 from power sector, 9 from iron and steel, 18 from cement, 16 from ammonia, and 3 from oil

  8. Estimation of spatially resolved road transport emissions for air quality management applications in the North West region of England

    Microsoft Academic Search

    S. J Lindley; D. E Conlan; D. W Raper; A. F. R Watson

    1999-01-01

    Spatially resolved estimates of combustion and non-combustion related emissions of CO, NOx, VOCs and PM from road transport sources have been made for the North West region of England in 1994. These have been generated using detailed emissions models for combustion related emissions of CO, NOx, VOCs and PM which take into account the different emissions profiles associated with particular

  9. Frame-Rate Spatial Referencing Based on Invariant Indexing and Alignment with Application to Online Retinal Image Registration

    Microsoft Academic Search

    Hong Shen; Charles V. Stewart; Badrinath Roysam; Gang Lin; Howard L. Tanenbaum

    2003-01-01

    This paper describes an algorithm to continually and accurately estimate the absolute location of a diagnostic or surgical tool (such as a laser) pointed at the human retina, from a series of image frames. We treat the problem as a registration problem using diagnostic images to build a spatial map of the retina and then registering each online image against

  10. Spatial and temporal single-cell volume estimation by a fluorescence imaging technique with application to astrocytes in primary culture

    NASA Astrophysics Data System (ADS)

    Khatibi, Siamak; Allansson, Louise; Gustavsson, Tomas; Blomstrand, Fredrik; Hansson, Elisabeth; Olsson, Torsten

    1999-05-01

    Cell volume changes are often associated with important physiological and pathological processes in the cell. These changes may be the means by which the cell interacts with its surrounding. Astroglial cells change their volume and shape under several circumstances that affect the central nervous system. Following an incidence of brain damage, such as a stroke or a traumatic brain injury, one of the first events seen is swelling of the astroglial cells. In order to study this and other similar phenomena, it is desirable to develop technical instrumentation and analysis methods capable of detecting and characterizing dynamic cell shape changes in a quantitative and robust way. We have developed a technique to monitor and to quantify the spatial and temporal volume changes in a single cell in primary culture. The technique is based on two- and three-dimensional fluorescence imaging. The temporal information is obtained from a sequence of microscope images, which are analyzed in real time. The spatial data is collected in a sequence of images from the microscope, which is automatically focused up and down through the specimen. The analysis of spatial data is performed off-line and consists of photobleaching compensation, focus restoration, filtering, segmentation and spatial volume estimation.

  11. Texture-based measurement of spatial frequency response using the dead leaves target: extensions, and application to real camera systems

    Microsoft Academic Search

    Jon McElvain; Scott P. Campbell; Jonathan Miller; Elaine W. Jin

    2010-01-01

    The dead leaves model was recently introduced as a method for measuring the spatial frequency response (SFR) of camera systems. The target consists of a series of overlapping opaque circles with a uniform gray level distribution and radii distributed as r-3. Unlike the traditional knife-edge target, the SFR derived from the dead leaves target will be penalized for systems that

  12. Texture-based measurement of spatial frequency response using the dead leaves target: extensions, and application to real camera systems

    Microsoft Academic Search

    Jon McElvain; Scott P. Campbell; Jonathan Miller; Elaine W. Jin

    2010-01-01

    The dead leaves model was recently introduced as a method for measuring the spatial frequency response (SFR) of camera systems. The target consists of a series of overlapping opaque circles with a uniform gray level distribution and radii distributed as r -3 . Unlike the traditional knife-edge target, the SFR derived from the dead leaves target will be penalized for

  13. Correlation and heritability in neuroimaging datasets: A spatial decomposition approach with application to an fMRI study of twins

    E-print Network

    Correlation and heritability in neuroimaging datasets: A spatial decomposition approach Accepted 23 June 2011 Available online 7 July 2011 Keywords: Heritability Intraclass correlation Twin study and function. Estimating the heritability of brain structure and function via twin studies has become one

  14. Investigation of Non-homogenous hidden Markov models and their Application to Spatially-distributed Precipitation Types 

    E-print Network

    Song, Jae Young

    2012-08-29

    . In this study, non-homogenous hidden Markov models (NHMM) are explored as a means of generating the probability of precipitation occurrence in small scale given large-scaled weather patterns. Three different spatial models: (1) independent (2) auto-logistic (3...

  15. A VORONOi-BASED PIVOT REPRESENTATION OF SPATIAL CONCEPTS AND ITS APPLICATION TO ROUTE DESCRIPTIONS EXPRESSED IN NATURAL LANGUAGE

    Microsoft Academic Search

    G. Edwards; G. Ligozat; A. Gryl; L. Fraczak

    1996-01-01

    Different representations of space are not in general equivalent. This point is clearly illustrated in research on the generation of sketches from route descriptions given in natural language: many linguistic expressions determine only partially a spatial situation. This article explores the role played by a pivot representation based on the Voronoi diagram. We study the use of this model in

  16. SEHR-ECHO v1.0: a Spatially-Explicit Hydrologic Response model for ecohydrologic applications

    NASA Astrophysics Data System (ADS)

    Schaefli, Bettina; Nicótina, Ludovico; Da Ronco, Pierfrancesco; Bertuzzo, Enrico; Rinaldo, Andrea

    2015-04-01

    We present here the SEHR-ECHO model, which stands for Spatially Explicit Hydrologic Response (SEHR) model developed at the Laboratory of Ecohydrology (ECHO) of the Ecole Polytechnique Fédérale de Lausanne. The model is being developed for the spatially-explicit simulation of streamflow and transport processes at the catchment scale. The key concept of the model is the formulation of water transport by geomorphologic travel time distributions: the mobilization of water (and possibly dissolved solutes) is simulated at the subcatchment scale and the resulting responses are convolved with the travel paths distribution within the river network to obtain the hydrologic response at the catchment outlet. The Matlab source code of the current version for alpine streamflow simulation is already freely available. A truly free open source version using Python will become available in the future.

  17. Applications of a GIS-based geotechnical tool to assess spatial earthquake hazards in an urban area

    Microsoft Academic Search

    Chang-Guk Sun

    A geotechnical information system (GTIS) was constructed within a spatial geographic information system (GIS) framework to\\u000a reliably predict geotechnical information and accurately estimate site effects at Gyeongju, an urban area in South Korea.\\u000a The system was built based on both collected and performed site investigation data in addition to acquired geo-knowledge data.\\u000a Seismic zoning maps were constructed using the site

  18. Spatially selective flash sublimation of small organic molecules for organic light-emitting diodes and display applications

    Microsoft Academic Search

    E. Becker; T. Riedl; T. Dobbertin; D. Schneider; D. Heithecker; D. Metzdorf; H. H. Johannes; W. Kowalsky

    2003-01-01

    A flash-sublimation technique for the spatially selective deposition of small organic molecules is presented. Single-pulse electrically heated copper stripes (width 100 mum) serve as heating elements. The relevant time scale of our technique is on the order of milliseconds. Under high vacuum conditions, the heating elements are used to locally flash-sublimate small-molecule material from a previously coated polyimide foil onto

  19. How well do regional climate models simulate the spatial dependence of precipitation? An application of pair-copula constructions

    NASA Astrophysics Data System (ADS)

    Hobæk Haff, Ingrid; Frigessi, Arnoldo; Maraun, Douglas

    2015-04-01

    We investigate how well a suite of regional climate models (RCMs) from the ENSEMBLES project represents the residual spatial dependence of daily precipitation. The study area we consider is a 200 km × 200 km region in south central Norway, with RCMs driven by ERA-40 boundary conditions at a horizontal resolution of approximately 25 km × 25 km. We model the residual spatial dependence with pair-copula constructions, which allows us to assess both the overall and tail dependence in precipitation, including uncertainty estimates. The selected RCMs reproduce the overall dependence rather well, though the discrepancies compared to observations are substantial. All models overestimate the overall dependence in the west-east direction. They also overestimate the upper tail dependence in the north-south direction during winter, and in the west-east direction during summer, whereas they tend to underestimate this dependence in the north-south direction in summer. Moreover, many of the climate models do not simulate the small-scale dependence patterns caused by the pronounced orography well. However, the misrepresented residual spatial dependence does not seem to affect estimates of high quantiles of extreme precipitation aggregated over a few grid boxes. The underestimation of the area-aggregated extreme precipitation is due mainly to the well-known underestimation of the univariate margins for individual grid boxes, suggesting that the correction of RCM biases in precipitation might be feasible.

  20. Application of the artificial neural network for reconstructing the internal-structure image of a random medium by spatial characteristics of backscattered optical radiation

    SciTech Connect

    Veksler, B A [Cranfield Health, Cranfield University, Silsoe (United Kingdom); Meglinskii, I V [N. G. Chernyshevskii Saratov State University, Saratov (Russian Federation)

    2008-06-30

    The feasibility of using an artificial neural network (ANN), which is the standard Matlab tool, for non-invasive (based on the data of backscattering) diagnostics of macro-inhomogeneities, localised at subsurface layers of the turbid strongly scattering medium was shown. The spatial and angle distribution of the backscattered optical radiation was calculated by using the Monte-Carlo method combining the modelling of effective optical paths and the use of statistical weights. It was shown that application of the backscattering method together with the ANN allows solving inverse problems for determining the average radius of the scattering particles and for reconstructing the images of structural elements within the medium with a high accuracy. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

  1. A Novel Algorithm Quantifying Pollutant Spatial Variability Using Flow Direction; Remote Retrieval and Surface-Network Applications

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Esswein, R.; Follette-Cook, M. B.

    2010-12-01

    Mapped patterns of aerosol and gas-phase species with distinct sources typically show strong directionality. Concentration fields remain relatively constant downwind, but some species remain correlated longer than others. Anisotropy of this sort is not strictly geographic; it varies by region and weather event, as local wind directions change. We describe and evaluate a novel method of estimating both spatial autocorrelation and directionality referenced to wind data. We use wind, geographic position, and concentration information from aircraft measurements such as NASA’s INTEX-NA, the TEXAQS Houston studies and WRF-Chem model simulations. Separation and bearing between sampling points are used, and but the bearing information are referenced to an average downwind-angle. Trajectory calculations are not required. | Variograms that we estimated from the large-regional INTEX-NA data suggested cross-wind autocorrelations of ca. 10 km, but along-wind autocorrelations of 5 to 10 times greater; species with shorter lifetimes and more distributed sources had shorter scales. Ozone-associated species had along-wind spatial scales increasing in the order NOx, HCHO, ozone, and CO, while aerosol characteristics had varying scales. Urban areas like Houston should be more dominated by sources, and along-wind spatial are expected to be shorter. Analyses of several days of WRF-Chem model results informed this analysis with uniform sampling. | Ignoring such wind information gives only a distorted view of “best estimates” when we have scattered surface or remotely sensed observations. This technique should aid formulation of GEO-CAPE air pollution and coastal-ocean special events, especially when there is partial cloud cover.

  2. Application of group analysis to the spatially homogeneous and isotropic Boltzmann equation with source using its Fourier image

    NASA Astrophysics Data System (ADS)

    Grigoriev, Yurii N.; Meleshko, Sergey V.; Suriyawichitseranee, Amornrat

    2015-06-01

    Group analysis of the spatially homogeneous and molecular energy dependent Boltzmann equations with source term is carried out. The Fourier transform of the Boltzmann equation with respect to the molecular velocity variable is considered. The correspondent determining equation of the admitted Lie group is reduced to a partial differential equation for the admitted source. The latter equation is analyzed by an algebraic method. A complete group classification of the Fourier transform of the Boltzmann equation with respect to a source function is given. The representation of invariant solutions and corresponding reduced equations for all obtained source functions are also presented.

  3. [Spatial heterogeneity of wind forcing: application to artificial reef functioning influenced by the circulation in the Bay of Marseilles, France].

    PubMed

    Pradal, Marie-Aude; Millet, Bertrand

    2006-07-01

    In the frame of the largest French project of artificial production reefs, initiated by the city of Marseilles in 2001, the present study aimed at describing the hydrodynamic pattern of the coastal area considered, by the use of a 3D numerical modelling. Results were local wind statistics, bottom current fields and drifting particle maps. The knowledge of the hydrodynamic connexions between particle (such as larvae) sources or targeted areas linked to the reefs, allows us to explain the success or failure of the reefs' colonizing. Moreover, the study confirms the wind spatial variability and demonstrates the error resulting from the use of an average but locally absent wind direction. PMID:16797460

  4. Texture-based measurement of spatial frequency response using the dead leaves target: extensions, and application to real camera systems

    NASA Astrophysics Data System (ADS)

    McElvain, Jon; Campbell, Scott P.; Miller, Jonathan; Jin, Elaine W.

    2010-01-01

    The dead leaves model was recently introduced as a method for measuring the spatial frequency response (SFR) of camera systems. The target consists of a series of overlapping opaque circles with a uniform gray level distribution and radii distributed as r-3. Unlike the traditional knife-edge target, the SFR derived from the dead leaves target will be penalized for systems that employ aggressive noise reduction. Initial studies have shown that the dead leaves SFR correlates well with sharpness/texture blur preference, and thus the target can potentially be used as a surrogate for more expensive subjective image quality evaluations. In this paper, the dead leaves target is analyzed for measurement of camera system spatial frequency response. It was determined that the power spectral density (PSD) of the ideal dead leaves target does not exhibit simple power law dependence, and scale invariance is only loosely obeyed. An extension to the ideal dead leaves PSD model is proposed, including a correction term to account for system noise. With this extended model, the SFR of several camera systems with a variety of formats was measured, ranging from 3 to 10 megapixels; the effects of handshake motion blur are also analyzed via the dead leaves target.

  5. High-Field fMRI for Human Applications: An Overview of Spatial Resolution and Signal Specificity

    PubMed Central

    Olman, Cheryl A; Yacoub, Essa

    2011-01-01

    In the last decade, dozens of 7 Tesla scanners have been purchased or installed around the world, while 3 Tesla systems have become a standard. This increased interest in higher field strengths is driven by a demonstrated advantage of high fields for available signal-to-noise ratio (SNR) in the magnetic resonance signal. Functional imaging studies have additional advantages of increases in both the contrast and the spatial specificity of the susceptibility based BOLD signal. One use of this resultant increase in the contrast to noise ratio (CNR) for functional MRI studies at high field is increased image resolution. However, there are many factors to consider in predicting exactly what kind of resolution gains might be made at high fields, and what the opportunity costs might be. The first part of this article discusses both hardware and image quality considerations for higher resolution functional imaging. The second part draws distinctions between image resolution, spatial specificity, and functional specificity of the fMRI signals that can be acquired at high fields, suggesting practical limitations for attainable resolutions of fMRI experiments at a given field, given the current state of the art in imaging techniques. Finally, practical resolution limitations and pulse sequence options for studies in human subjects are considered. PMID:22216080

  6. Discovering fuzzy spatial association rules

    NASA Astrophysics Data System (ADS)

    Kacar, Esen; Cicekli, Nihan K.

    2002-03-01

    Discovering interesting, implicit knowledge and general relationships in geographic information databases is very important to understand and use these spatial data. One of the methods for discovering this implicit knowledge is mining spatial association rules. A spatial association rule is a rule indicating certain association relationships among a set of spatial and possibly non-spatial predicates. In the mining process, data is organized in a hierarchical manner. However, in real-world applications it may not be possible to construct a crisp structure for this data, instead some fuzzy structures should be used. Fuzziness, i.e. partial belonging of an item to more than one sub-item in the hierarchy, could be applied to the data itself, and also to the hierarchy of spatial relations. This paper shows that, strong association rules can be mined from large spatial databases using fuzzy concept and spatial relation hierarchies.

  7. Achievements of the DOT-NASA Joint Program on Remote Sensing and Spatial Information Technologies: Application to Multimodal Transportation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This report presents three-year accomplishments from the national program on Commercial Remote Sensing and Geospatial Technology (CRSGT) application to transportation, administered by the U.S. Department of Transportation (U.S. DOT) in collaboration with the National Aeronautics and Space Administration (NASA). The joint program was authorized under Section 5113 of the Transportation Equity Act for the 21st Century (TEA-21). This is the first national program of its type focusing on transportation applications of emerging commercial remote sensing technologies. U.S. DOT's Research and Special Programs Administration manages the program in coordination with NASA's Earth Science Enterprise's application programs. The program focuses on applications of CRSGT products and systems for providing smarter and more efficient transportation operations and services. The program is performed in partnership with four major National Consortia for Remote Sensing in Transportation (NCRST). Each consortium focuses on research and development of products in one of the four priority areas for transportation application, and includes technical application and demonstration projects carried out in partnership with industries and service providers in their respective areas. The report identifies products and accomplishments from each of the four consortia in meeting the goal of providing smarter and more efficient transportation services. The products and results emerging from the program are being implemented in transportation operations and services through state and local agencies. The Environmental Assessment and Application Consortium (NCRST-E) provides leadership for developing and deploying cost effective environmental and transportation planning services, and integrates CRSGT advances for achieving smarter and cost effective corridor planning. The Infrastructure Management Consortium (NCRST-I) provides leadership in technologies that achieve smarter and cheaper ways of managing transportation infrastructure assets, operation, and inspection, and integrates CRSGT advances for achieving infrastructure security. The Traffic Flow Consortium (NCRST-F) provides leadership to develop new tools for regional traffic flow management including heavy vehicles and intermodal flow of freight, and integrates CRSGT advances for complementing and extending the reach of ITS user services. The Safety, Hazards and Disasters (NCRST-H) provides leadership for deploying remote sensing technology to locate transportation hazards and improve disaster recovery, and integrates CRSGT advances for application to protect transportation systems from terrorism. The DOT-NASA team is proud to present this report of accomplishments on products and results emerging from the joint program for application to transportation practice.

  8. Spatial variability of soil total and DTPA-extractable cadmium caused by long-term application of phosphate fertilizers, crop rotation, and soil characteristics.

    PubMed

    Jafarnejadi, A R; Sayyad, Gh; Homaee, M; Davamei, A H

    2013-05-01

    Increasing cadmium (Cd) accumulation in agricultural soils is undesirable due to its hazardous influences on human health. Thus, having more information on spatial variability of Cd and factors effective to increase its content on the cultivated soils is very important. Phosphate fertilizers are main contamination source of cadmium (Cd) in cultivated soils. Also, crop rotation is a critical management practice which can alter soil Cd content. This study was conducted to evaluate the effects of long-term consumption of the phosphate fertilizers, crop rotations, and soil characteristics on spatial variability of two soil Cd species (i.e., total and diethylene triamine pentaacetic acid (DTPA) extractable) in agricultural soils. The study was conducted in wheat farms of Khuzestan Province, Iran. Long-term (27-year period (1980 to 2006)) data including the rate and the type of phosphate fertilizers application, the respective area, and the rotation type of different regions were used. Afterwards, soil Cd content (total or DTPA extractable) and its spatial variability in study area (400,000 ha) were determined by sampling from soils of 255 fields. The results showed that the consumption rate of di-ammonium phosphate fertilizer have been varied enormously in the period study. The application rate of phosphorus fertilizers was very high in some subregions with have extensive agricultural activities (more than 95 kg/ha). The average and maximum contents of total Cd in the study region were obtained as 1.47 and 2.19 mg/kg and DTPA-extractable Cd as 0.084 and 0.35 mg/kg, respectively. The spatial variability of Cd indicated that total and DTPA-extractable Cd contents were over 0.8 and 0.1 mg/kg in 95 and 25 % of samples, respectively. The spherical model enjoys the best fitting and lowest error rate to appraise the Cd content. Comparing the phosphate fertilizer consumption rate with spatial variability of the soil cadmium (both total and DTPA extractable) revealed the high correlation between the consumption rate of P fertilizers and soil Cd content. Rotation type was likely the main effective factor on variations of the soil DTPA-extractable Cd contents in some parts (eastern part of study region) and could explain some Cd variation. Total Cd concentrations had significant correlation with the total neutralizing value (p < 0.01), available P (p < 0.01), cation exchange capacity (p < 0.05), and organic carbon (p < 0.05) variables. The DTPA-extractable Cd had significant correlation with OC (p < 0.01), pH, and clay content (p < 0.05). Therefore, consumption rate of the phosphate fertilizers and crop rotation are important factors on solubility and hence spatial variability of Cd content in agricultural soils. PMID:22948289

  9. Approximate message-passing with spatially coupled structured operators, with applications to compressed sensing and sparse superposition codes

    NASA Astrophysics Data System (ADS)

    Barbier, Jean; Schülke, Christophe; Krzakala, Florent

    2015-05-01

    We study the behavior of approximate message-passing (AMP), a solver for linear sparse estimation problems such as compressed sensing, when the i.i.d matrices—for which it has been specifically designed—are replaced by structured operators, such as Fourier and Hadamard ones. We show empirically that after proper randomization, the structure of the operators does not significantly affect the performances of the solver. Furthermore, for some specially designed spatially coupled operators, this allows a computationally fast and memory efficient reconstruction in compressed sensing up to the information-theoretical limit. We also show how this approach can be applied to sparse superposition codes, allowing the AMP decoder to perform at large rates for moderate block length.

  10. Autonomous spatially adaptive sampling in experiments based on curvature, statistical error and sample spacing with applications in LDA measurements

    NASA Astrophysics Data System (ADS)

    Theunissen, Raf; Kadosh, Jesse S.; Allen, Christian B.

    2015-06-01

    Spatially varying signals are typically sampled by collecting uniformly spaced samples irrespective of the signal content. For signals with inhomogeneous information content, this leads to unnecessarily dense sampling in regions of low interest or insufficient sample density at important features, or both. A new adaptive sampling technique is presented directing sample collection in proportion to local information content, capturing adequately the short-period features while sparsely sampling less dynamic regions. The proposed method incorporates a data-adapted sampling strategy on the basis of signal curvature, sample space-filling, variable experimental uncertainty and iterative improvement. Numerical assessment has indicated a reduction in the number of samples required to achieve a predefined uncertainty level overall while improving local accuracy for important features. The potential of the proposed method has been further demonstrated on the basis of Laser Doppler Anemometry experiments examining the wake behind a NACA0012 airfoil and the boundary layer characterisation of a flat plate.

  11. The SAHGA model to calculate the Spatial Ammoniacal Heterogeneity at the soil surface after fertiliser Granule Application

    Microsoft Academic Search

    Edith Le Cadre; Sophie Génermont; Farooq Azam; Sylvie Recous

    2004-01-01

    After dissolution of fertiliser granules, a high nitrogen concentration is recovered in the immediate vicinity of granules, which may enhance damaging processes like nitrite accumulation or ammonia volatilisation. Based on the diffusion equations of Cranck, the granule-soil microsite was modelled to obtain the actual fertilised surface plot and the effective rate of N application on this surface. Parameterisation of the

  12. Spatial Displays and Spatial Instruments

    NASA Technical Reports Server (NTRS)

    Ellis, Stephen R. (editor); Kaiser, Mary K. (editor); Grunwald, Arthur J. (editor)

    1989-01-01

    The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles.

  13. Development of high-spatial and high-mass resolution mass spectrometric imaging (MSI) and its application to the study of small metabolites and endogenous molecules of plants

    SciTech Connect

    Jun, Ji Hyun

    2011-11-30

    High-spatial and high-mass resolution laser desorption ionization (LDI) mass spectrometric (MS) imaging technology was developed for the attainment of MS images of higher quality containing more information on the relevant cellular and molecular biology in unprecedented depth. The distribution of plant metabolites is asymmetric throughout the cells and tissues, and therefore the increase in the spatial resolution was pursued to reveal the localization of plant metabolites at the cellular level by MS imaging. For achieving high-spatial resolution, the laser beam size was reduced by utilizing an optical fiber with small core diameter (25 ?m) in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer. Matrix application was greatly improved using oscillating capillary nebulizer. As a result, single cell level spatial resolution of ~ 12 ?m was achieved. MS imaging at this high spatial resolution was directly applied to a whole Arabidopsis flower and the substructures of an anther and single pollen grains at the stigma and anther were successfully visualized. MS imaging of high spatial resolution was also demonstrated to the secondary roots of Arabidopsis thaliana and a high degree of localization of detected metabolites was successfully unveiled. This was the first MS imaging on the root for molecular species. MS imaging with high mass resolution was also achieved by utilizing the LTQ-Orbitrap mass spectrometer for the direct identification of the surface metabolites on the Arabidopsis stem and root and differentiation of isobaric ions having the same nominal mass with no need of tandem mass spectrometry (MS/MS). MS imaging at high-spatial and high-mass resolution was also applied to cer1 mutant of the model system Arabidopsis thaliana to demonstrate its usefulness in biological studies and reveal associated metabolite changes in terms of spatial distribution and/or abundances compared to those of wild-type. The spatial distribution of targeted metabolites, mainly waxes and flavonoids, was systematically explored on various organs, including flowers, leaves, stems, and roots at high spatial resolution of ~ 12-50 ?m and the changes in the abundance level of these metabolites were monitored on the cer1 mutant with respect to the wild-type. This study revealed the metabolic biology of CER1 gene on each individual organ level with very detailed high spatial resolution. The separate MS images of isobaric metabolites, i.e. C29 alkane vs. C28 aldehyde could be constructed on both genotypes from MS imaging at high mass resolution. This allows tracking of abundance changes for those compounds along with the genetic mutation, which is not achievable with low mass resolution mass spectrometry. This study supported previous hypothesis of molecular function of CER1 gene as aldehyde decarbonylase, especially by displaying hyper accumulation of aldehydes and C30 fatty acid and decrease in abundance of alkanes and ketones in several plant organs of cer1 mutant. The scope of analytes was further directed toward internal cell metabolites from the surface metabolites of the plant. MS profiling and imaging of internal cell metabolites were performed on the vibratome section of Arabidopsis leaf. Vibratome sectioning of the leaf was first conducted to remove the surface cuticle layer and it was followed by enzymatic treatment of the section to induce the digestion of primary cell walls, middle lamella, and expose the internal cells underneath to the surface for detection with the laser by LDI-MS. The subsequent MS imaging onto the enzymatically treated vibratome section allowed us to map the distribution of the metabolites in the internal cell layers, linolenic acid (C18:3 FA) and linoleic acid (C18:2 FA). The development of an assay for relative quantification of analytes at the single subcellular/organelle level by LDI-MS imaging was attempted and both plausibility and significant obstacles were seen. As a test system, native plant organelle, chloroplasts isolated from the spinach leaves were used

  14. Spatial distribution of the electrical conductivity in highly filled polymers: Experiment, modeling, and application to bipolar plates

    NASA Astrophysics Data System (ADS)

    Planes, E.; Gloaguen, F.; Albérola, N.; Flandin, L.

    2013-12-01

    A large variety of composites for electrical applications are developed worldwide on a daily basis. Most of these materials are made from carbonaceous fillers dispersed in polymers. The optimization of the formulations is complex and depends on parameters that are difficult to identify ab initio. The results might also be very sensitive to the processing conditions. There is therefore a need for a fast and accurate method to measure the electrical properties of samples with unfamiliar geometric features and without altering their shape. A four point probes method is incremented that fulfills all the above mentioned requirements. An analytical model is proposed that extends Uhlirs theory and permits to quickly determine the resistivity distribution. Experimental and theoretical approaches were performed to validate the method. An example is proposed with the measurement of samples initially designed for fuel cell-bipolar plates-application.

  15. Combining Conservation Value, Vulnerability, and Effectiveness of Mitigation Actions in Spatial Conservation Decisions: An Application to Coastal Oil Spill Combating

    NASA Astrophysics Data System (ADS)

    Ihaksi, Taina; Kokkonen, Teemu; Helle, Inari; Jolma, Ari; Lecklin, Tiina; Kuikka, Sakari

    2011-05-01

    Increasing oil transportation and severe oil accidents in the past have led to the development of various sensitivity maps in different countries all over the world. Often, however, the areas presented on the maps are far too large to be safeguarded with the available oil combating equipment and prioritization is required to decide which areas must be safeguarded. While oil booms can be applied to safeguard populations from a drifting oil slick, decision making on the spatial allocation of oil combating capacity is extremely difficult due to the lack of time, resources and knowledge. Since the operational decision makers usually are not ecologists, a useful decision support tool including ecological knowledge must be readily comprehensible and easy to use. We present an index-based method that can be used to make decisions concerning which populations of natural organisms should primarily be safeguarded from a floating oil slick with oil booms. The indices take into account the relative exposure, mortality and recovery potential of populations, the conservation value of species and populations, and the effectiveness of oil booms to safeguard different species. The method has been implemented in a mapping software that can be used in the Gulf of Finland (Baltic Sea) for operational oil combating. It could also be utilized in other similar conservation decisions where species with varying vulnerability, conservational value, and benefits received from the management actions need to be prioritized.

  16. Combining conservation value, vulnerability, and effectiveness of mitigation actions in spatial conservation decisions: an application to coastal oil spill combating.

    PubMed

    Ihaksi, Taina; Kokkonen, Teemu; Helle, Inari; Jolma, Ari; Lecklin, Tiina; Kuikka, Sakari

    2011-05-01

    Increasing oil transportation and severe oil accidents in the past have led to the development of various sensitivity maps in different countries all over the world. Often, however, the areas presented on the maps are far too large to be safeguarded with the available oil combating equipment and prioritization is required to decide which areas must be safeguarded. While oil booms can be applied to safeguard populations from a drifting oil slick, decision making on the spatial allocation of oil combating capacity is extremely difficult due to the lack of time, resources and knowledge. Since the operational decision makers usually are not ecologists, a useful decision support tool including ecological knowledge must be readily comprehensible and easy to use. We present an index-based method that can be used to make decisions concerning which populations of natural organisms should primarily be safeguarded from a floating oil slick with oil booms. The indices take into account the relative exposure, mortality and recovery potential of populations, the conservation value of species and populations, and the effectiveness of oil booms to safeguard different species. The method has been implemented in a mapping software that can be used in the Gulf of Finland (Baltic Sea) for operational oil combating. It could also be utilized in other similar conservation decisions where species with varying vulnerability, conservational value, and benefits received from the management actions need to be prioritized. PMID:21437741

  17. Spatial management of information

    Microsoft Academic Search

    William C. Donelson

    1978-01-01

    Methods of spatially managing data are currently under study at the Architecture Machine Group. Management concepts are drawn from everyday examples of paper and document handling. However, the work elaborates data types to include: animation, movies, and sound-sync computer graphics. Beyond the application of management information systems, the paper portrays a sophisticated surround of keyboardless, interactive, and large scale graphics.

  18. Effect of spatial confinement on magnetic hyperthermia via dipolar interactions in Fe?O? nanoparticles for biomedical applications.

    PubMed

    Sadat, M E; Patel, Ronak; Sookoor, Jason; Bud'ko, Sergey L; Ewing, Rodney C; Zhang, Jiaming; Xu, Hong; Wang, Yilong; Pauletti, Giovanni M; Mast, David B; Shi, Donglu

    2014-09-01

    In this work, the effect of nanoparticle confinement on the magnetic relaxation of iron oxide (Fe3O4) nanoparticles (NP) was investigated by measuring the hyperthermia heating behavior in high frequency alternating magnetic field. Three different Fe3O4 nanoparticle systems having distinct nanoparticle configurations were studied in terms of magnetic hyperthermia heating rate and DC magnetization. All magnetic nanoparticle (MNP) systems were constructed using equivalent ~10nm diameter NP that were structured differently in terms of configuration, physical confinement, and interparticle spacing. The spatial confinement was achieved by embedding the Fe3O4 nanoparticles in the matrices of the polystyrene spheres of 100 nm, while the unconfined was the free Fe3O4 nanoparticles well-dispersed in the liquid via PAA surface coating. Assuming the identical core MNPs in each system, the heating behavior was analyzed in terms of particle freedom (or confinement), interparticle spacing, and magnetic coupling (or dipole-dipole interaction). DC magnetization data were correlated to the heating behavior with different material properties. Analysis of DC magnetization measurements showed deviation from classical Langevin behavior near saturation due to dipole interaction modification of the MNPs resulting in a high magnetic anisotropy. It was found that the Specific Absorption Rate (SAR) of the unconfined nanoparticle systems were significantly higher than those of confined (the MNPs embedded in the polystyrene matrix). This increase of SAR was found to be attributable to high Néel relaxation rate and hysteresis loss of the unconfined MNPs. It was also found that the dipole-dipole interactions can significantly reduce the global magnetic response of the MNPs and thereby decrease the SAR of the nanoparticle systems. PMID:25063092

  19. Effect of spatial confinement on magnetic hyperthermia via dipolar interactions in Fe3O4 nanoparticles for biomedical applications

    SciTech Connect

    Sadat, M E [University of Cincinnati; Patel, Ronak [University of Cincinnati; Sookoor, Jason [University of Cincinnati; Bud'ko, Sergey L [Ames Laboratory; Ewing, Rodney C [Stanford University; Zhang, Jiaming [Stanford University; Xu, Hong [Shanghai Jiao Tong University; Wang, Yilong [Tongji University School of Medicine; Pauletti, Giovanni M [University of Cincinnati; Mast, David B [University of Cincinnati; Shi, Donglu [University of Cincinnati

    2014-09-01

    In this work, the effect of nanoparticle confinement on the magnetic relaxation of iron oxide (Fe3O4) nanoparticles (NP) was investigated by measuring the hyperthermia heating behavior in high frequency alternating magnetic field. Three different Fe3O4 nanoparticle systems having distinct nanoparticle configurations were studied in terms of magnetic hyperthermia heating rate and DC magnetization. All magnetic nanoparticle (MNP) systems were constructed using equivalent ~10nm diameter NP that were structured differently in terms of configuration, physical confinement, and interparticle spacing. The spatial confinement was achieved by embedding the Fe3O4 nanoparticles in the matrices of the polystyrene spheres of 100 nm, while the unconfined was the free Fe3O4 nanoparticles well-dispersed in the liquid via PAA surface coating. Assuming the identical core MNPs in each system, the heating behavior was analyzed in terms of particle freedom (or confinement), interparticle spacing, and magnetic coupling (or dipole-dipole interaction). DC magnetization data were correlated to the heating behavior with different material properties. Analysis of DC magnetization measurements showed deviation from classical Langevin behavior near saturation due to dipole interaction modification of the MNPs resulting in a high magnetic anisotropy. It was found that the Specific Absorption Rate (SAR) of the unconfined nanoparticle systems were significantly higher than those of confined (the MNPs embedded in the polystyrene matrix). This increase of SAR was found to be attributable to high Néel relaxation rate and hysteresis loss of the unconfined MNPs. It was also found that the dipole-dipole interactions can significantly reduce the global magnetic response of the MNPs and thereby decrease the SAR of the nanoparticle systems.

  20. Retrieval techniques for airborne imaging of methane concentrations using high spatial and moderate spectral resolution: application to AVIRIS

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Frankenberg, C.; Roberts, D. A.

    2013-09-01

    Two quantitative retrieval techniques were evaluated to estimate methane (CH4) enhancement in concentrated plumes using high spatial and moderate spectral resolution data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). An Iterative Maximum a Posteriori Differential Optical Absorption Spectroscopy (IMAP-DOAS) algorithm performed well for an ocean scene containing natural CH4 emissions from the Coal Oil Point (COP) seep field near Santa Barbara, California. IMAP-DOAS retrieval precision errors are expected to equal between 0.31 to 0.61 ppm CH4 over the lowest atmospheric layer (height up to 1.04 km), corresponding to about a 30 to 60 ppm error for a 10 m thick plume. However, IMAP-DOAS results for a terrestrial scene were adveresly influenced by the underlying landcover. A hybrid approach using Singular Value Decomposition (SVD) was particularly effective for terrestrial surfaces because it could better account for spectral variability in surface reflectance. Using this approach, a CH4 plume was observed immediately downwind of two hydrocarbon storage tanks at the Inglewood Oil Field in Los Angeles, California, with a maximum near surface enhancement of 8.45 ppm above background. At COP, the distinct plume had a maximum enhancement of 2.85 ppm CH4 above background and was consistent with known seep locations and local wind direction. A sensitivity analysis also indicates CH4 sensitivity should be more than doubled for the next generation AVIRIS sensor (AVIRISng) due to improved spectral resolution and sampling. AVIRIS-like sensors offer the potential to better constrain emissions on local and regional scales, including sources of increasing concern like industrial point source emissions and fugitive CH4 from the oil and gas industry.

  1. Retrieval techniques for airborne imaging of methane concentrations using high spatial and moderate spectral resolution: application to AVIRIS

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Frankenberg, C.; Roberts, D. A.

    2014-02-01

    Two quantitative retrieval techniques were evaluated to estimate methane (CH4) enhancement in concentrated plumes using high spatial and moderate spectral resolution data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). An iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS) algorithm performed well for an ocean scene containing natural CH4 emissions from the Coal Oil Point (COP) seep field near Santa Barbara, California. IMAP-DOAS retrieval precision errors are expected to equal between 0.31 to 0.61 ppm CH4 over the lowest atmospheric layer (height up to 1.04 km), corresponding to about a 30 to 60 ppm error for a 10 m thick plume. However, IMAP-DOAS results for a terrestrial scene were adversely influenced by the underlying land cover. A hybrid approach using singular value decomposition (SVD) was particularly effective for terrestrial surfaces because it could better account for spectral variability in surface reflectance. Using this approach, a CH4 plume was observed extending 0.1 km downwind of two hydrocarbon storage tanks at the Inglewood Oil Field in Los Angeles, California (USA) with a maximum near surface enhancement of 8.45 ppm above background. At COP, the distinct plume had a maximum enhancement of 2.85 ppm CH4 above background, and extended more than 1 km downwind of known seep locations. A sensitivity analysis also indicates CH4 sensitivity should be more than doubled for the next generation AVIRIS sensor (AVIRISng) due to improved spectral resolution and sampling. AVIRIS-like sensors offer the potential to better constrain emissions on local and regional scales, including sources of increasing concern like industrial point source emissions and fugitive CH4 from the oil and gas industry.

  2. Spatial Concepts and Spatial Reasoning in the Social Sciences

    E-print Network

    Fabrikant, Sara Irina

    to measure understanding, learning, & skill development spatial@ucsb Focus: · Geospatial concepts in social: · Identify fundamental geospatial concepts · Context dependent applications (re: disciplines, theory;Geospatial Concepts in the Social Sciences · Location ­ Understanding formal & informal methods of specifying

  3. Spatial data interoperability for multi-platform GIS based on Oracle Spatial

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Zhu, Xinyan

    2006-10-01

    Spatial data sharing among multiple GIS (Geographic Information System) platforms is a fundamental requirement of many GIS applications, yet conventional methods of spatial data interoperability don't adequately consider practical application circumstance, which now becomes a primary barrier to more efficient spatial data sharing among multiple GIS platforms. In this paper, after analyzing the disadvantages of conventional methods and the causation of the disadvantages, and analyzing the principle of spatial data access of ArcGIS, MapInfo and GeoStar based on Oracle Spatial storage, the authors propose a new spatial data interoperability method called Different meta information and Same spatial data Method. This method is based on Oracle Spatial, through which spatial data interoperability for multi-platform of GIS is available. The results of experiments demonstrate that this method is a new simple practical approach adapted for current application circumstance, and it provides us a new idea for spatial data interoperability.

  4. GEO-RBAC: a spatially aware RBAC

    Microsoft Academic Search

    Elisa Bertino; Barbara Catania; Maria Luisa Damiani; Paolo Perlasca

    2005-01-01

    Securing access to data in location-based services and mobile applications requires the definition of spatially aware access control systems. Even if some approaches have already been proposed either in the context of geographic database systems or context-aware applications, a comprehensive framework, general and flexible enough to cope with spatial aspects in real mobile applications, is still missing. In this paper,

  5. Development of a statistical model to identify spatial and meteorological drivers of elevated O3 in Nevada and its application to other rural mountainous regions.

    PubMed

    Fine, Rebekka; Miller, Matthieu B; Gustin, Mae Sexauer

    2015-10-15

    Measurements of O3 at relatively remote monitoring sites are useful for quantifying baseline O3, and subsequently the magnitude of O3 not controllable by local regulations. As the National Ambient Air Quality Standard (NAAQS) for O3 becomes more stringent, there is an increased need to quantify baseline O3 particularly in the Western US, where regional and global sources can significantly enhance O3 measured at surface sites, yielding baseline mixing ratios approaching or exceeding the NAAQS threshold. Past work has indicated that meteorological conditions as well as site specific spatial characteristics (e.g. elevation, basin size, gradient) are significantly correlated with O3 intercepted at rural monitoring sites. Here, we use 3years of measurements from sites throughout rural Nevada to develop a categorical tree model to identify spatial and meteorological characteristics that are associated with elevated baseline O3. Data from other sites in the Intermountain Western US are used to test the applicability of the model for sites throughout the region. Our analyses indicate that increased elevation and basin size were associated with increased frequency of elevated O3. On a daily time scale, relative humidity had the strongest association with observed MDA8 O3. Seventy-four percent of MDA8 O3 observations>60ppbv occurred when daily minimum relative humidity was <15%. Further, we found that including ancillary pollutant data did not improve the predictive accuracy for measurements >60ppbv whereas including upper air meteorological measurements improved the accuracy of predicting periods when O3 was >60ppbv. These findings indicate that transport, rather than local production, influences O3 measurements in Nevada, and that high elevation sites in rural Nevada, are representative of baseline conditions in the Intermountain Western US. PMID:25895623

  6. Application of GIS and logistic regression to fossil pollen data in modelling present and past spatial distribution of the Colombian savanna

    NASA Astrophysics Data System (ADS)

    Flantua, Suzette G. A.; van Boxel, John H.; Hooghiemstra, Henry; van Smaalen, John

    2007-12-01

    Climate changes affect the abundance, geographic extent, and floral composition of vegetation, which are reflected in the pollen rain. Sediment cores taken from lakes and peat bogs can be analysed for their pollen content. The fossil pollen records provide information on the temporal changes in climate and palaeo-environments. Although the complexity of the variables influencing vegetation distribution requires a multi-dimensional approach, only a few research projects have used GIS to analyse pollen data. This paper presents a new approach to palynological data analysis by combining GIS and spatial modelling. Eastern Colombia was chosen as a study area owing to the migration of the forest-savanna boundary since the last glacial maximum, and the availability of pollen records. Logistic regression has been used to identify the climatic variables that determine the distribution of savanna and forest in eastern Colombia. These variables were used to create a predictive land-cover model, which was subsequently implemented into a GIS to perform spatial analysis on the results. The palynological data from the study area were incorporated into the GIS. Reconstructed maps of past vegetation distribution by interpolation showed a new approach of regional multi-site data synthesis related to climatic parameters. The logistic regression model resulted in a map with 85.7% predictive accuracy, which is considered useful for the reconstruction of future and past land-cover distributions. The suitability of palynological GIS application depends on the number of pollen sites, the distribution of the pollen sites over the area of interest, and the degree of overlap of the age ranges of the pollen records.

  7. A spatial analysis of cultural ecosystem service valuation by regional stakeholders in Florida: a coastal application of the social values for ecosystem services (SolVES) tool

    USGS Publications Warehouse

    Coffin, Alisa W.; Swett, Robert A.; Cole, Zachary D.

    2012-01-01

    Livelihoods and lifestyles of people throughout the world depend on essential goods and services provided by marine and coastal ecosystems. However, as societal demand increases and available ocean and coastal space diminish, better methods are needed to spatially and temporally allocate ocean and coastal activities such as shipping, energy production, tourism, and fishing. While economic valuation is an important mechanism for doing so, cultural ecosystem services often do not lend themselves to this method. Researchers from the U.S. Geological Survey are working collaboratively with the Florida Sea Grant College Program to map nonmonetary values of cultural ecosystem services for a pilot area (Sarasota Bay) in the Gulf of Mexico. The research seeks to close knowledge gaps about the attitudes and perceptions, or nonmonetary values, held by coastal residents toward cultural ecosystem services, and to adapt related, terrestrial-based research methods to a coastal setting. A critical goal is to integrate research results with coastal and marine spatial planning applications, thus making them relevant to coastal planners and managers in their daily efforts to sustainably manage coastal resources. Using information about the attitudes and preferences of people toward places and uses in the landscape, collected from value and preference surveys, the USGS SolVES 2.0 tool will provide quantitative models to relate social values, or perceived nonmonetary values, assigned to locations by survey respondents with the underlying environmental characteristics of those same locations. Project results will increase scientific and geographic knowledge of how Sarasota Bay residents value their area’s cultural ecosystem services.

  8. SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations

    E-print Network

    Zacks, Jeffrey M.

    SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations Multiple Systems for Spatial Imagery: Transformations of Objects and Bodies Jeffrey M. Zacks* and Barbara Tversky * Washington COGNITION & COMPUTATION #12;SPATIAL TRANSFORMATIONS 2 Abstract Problem-solving often requires imagining

  9. Research on Spatial Data Emergency Coordinating and Sharing System Construction

    Microsoft Academic Search

    Cheng Dong; Jia Chang Chen

    2009-01-01

    The importance of spatial data application has been fully displayed in Wenchuan earthquake relief activities. Spatial data has been the basic factor of various relief activities. Wenchuan earthquake relief process also uncovered many problems on the spatial data emergency application of our country. The exertion of spatial data has been greatly controlled by the coordination capability of each department during

  10. Spatial Mass

    E-print Network

    Benjamin Nachman; Ariel Schwartzman

    2014-07-08

    In analogy to the transverse mass constructed from two objects, we define the spatial mass constructed from the input objects 3-vector momenta. This observable is insensitive to jet mass scale and resolution uncertainties when constructed from small-radius hadronic jets. Thus it improves the effective resolution on multijet masses for searches and measurements in hadronic final states. To illustrate the efficacy of the spatial mass, we consider a top quark mass measurement at the Large Hadron Collider (LHC) in the 3-jet final state. The reduction in uncertainty comes with a negligible cost in sensitivity.

  11. Oracle Spatial User's Guide and Reference

    E-print Network

    Shahabi, Cyrus

    Oracle® Spatial User's Guide and Reference 10g Release 1 (10.1) Part No. B10826-01 December 2003 applications using Oracle Spatial and Oracle Locator. #12;Oracle Spatial User's Guide and Reference, 10g Release 1 (10.1) Part No. B10826-01 Copyright © 1999, 2003 Oracle Corporation. All rights reserved

  12. Spatially resolved PMD measurements

    Microsoft Academic Search

    Andrea Galtarossa; Luca Palmieri

    2004-01-01

    Spatially resolved measurements of polarization properties of fiber optic link-such as birefringence, polarization-mode dispersion (PMD) and polarization dependent loss (PDL)-may be effectively performed using polarization sensitive reflectometric techniques. In particular, this paper focuses on polarization-OTDR and reviews its theory and applications. Special emphasis is given to the use of optical reflectometry as a tool to characterize fiber birefringence. This allows

  13. Spatial Regression for Marked Point Processes

    Microsoft Academic Search

    KATJA ICKSTADT; ROBERT L. WOLPERT

    1998-01-01

    SUMMARY In a wide range of applications, dependence on smoothly-varying covariates leads spatial point count intensities to feature positive correlation for nearby loc ations. In applications where the points are \\

  14. Temporal and spatial variability of groundwater–surface water fluxes: Development and application of an analytical method using temperature time series

    Microsoft Academic Search

    John Keery; Andrew Binley; Nigel Crook; Jonathan W. N. Smith

    2007-01-01

    Summary Significant spatial and temporal variability of water fluxes may exist at the river-groundwater interface and the assessment of such variability may be important for appreciation of the spatial and temporal dynamics of chemical loading to a river or aquifer. Measurement of such variability is limited due to difficulties of applying conven- tional Darcian flux based methods. Thermal parameters required

  15. 1360 IEEE Transactions on Power Systems, Vol. 12, No. 3, August 1997 Application of Fuzzy Logic Technology for Spatial Load Forecasting

    E-print Network

    Chow, Mo-Yuen

    Technology for Spatial Load Forecasting MO-yuen Chow Hahn Tram IEEE Senior Member Dept. of Electrical for anticipated future load growth under different possible scenarios. Their decisions and designs can affect logic to fuse the available information for spatial load forecasting. The proposed scheme can provide

  16. Clinical application of BASING and spectral/spatial water and lipid suppression pulses for prostate cancer staging and localization by in vivo 3D 1H magnetic resonance spectroscopic imaging.

    PubMed

    Males, R G; Vigneron, D B; Star-Lack, J; Falbo, S C; Nelson, S J; Hricak, H; Kurhanewicz, J

    2000-01-01

    In previous in situ point-resolved spectroscopy (PRESS) three-dimensional (3D) 1H magnetic resonance (MR) spectroscopic imaging studies, it has been demonstrated that the ratio of prostatic metabolites can noninvasively discriminate prostate cancer from surrounding normal tissue. However, in these studies, conventional chemical shift selective suppression (CHESS) and short-time inversion recovery (STIR) techniques often resulted in inadequate water and lipid suppression. To improve suppression and spatial coverage, the newly developed T1 insensitive dual band selective inversion with gradient dephasing (BASING) Bandstop Filter and dual phase-compensating spectral/spatial spin-echo pulses have been implemented in a clinical setting. In phantom studies, no change in metabolic profiles was observed with application of either BASING or spectral/spatial pulses. In a study of 17 prostate cancer patients, the use of either BASING or spectral/spatial pulses allowed for suppression of water (BASING 99.80 +/- 0.14% and spectral/spatial 99.73 +/- 0.47%) and lipid (BASING 98.56 +/- 1.03% and spectral/spatial 98.44 +/- 1.90%) without a significant difference in the prostatic metabolite ratios. Spectral/spatial suppression has the added advantage of reducing the chemical shift dependence of the PRESS volume, but optimal performance requires high-speed gradients with negligible eddy current effects. BASING suppression is less reliant on accurate pulse and gradient timings and can be implemented easily with no loss in performance on clinical MR scanners with conventional gradients. PMID:10642727

  17. Towards spatially distributed flood forecasts in flash flood prone areas: application to the supervision of a road network in the South of France

    NASA Astrophysics Data System (ADS)

    Naulin, Jean-Philippe; Payrastre, Olivier; Gaume, Eric; Delrieu, Guy

    2013-04-01

    Accurate flood forecasts are crucial for an efficient flood event management. Until now, hydro-meteorological forecasts have been mainly used for early-warnings in France (Meteorological and flood vigilance maps) or over the world (Flash-flood guidances). These forecasts are generally limited to the main streams covered by the flood forecasting services or to specific watersheds with particular assets like check dams which are in most cases well gauged river sections, leaving aside large parts of the territory. A distributed hydro-meteorological forecasting approach will be presented, able to take advantage of the high spatial and temporal resolution rainfall estimates that are now available to provide information at ungauged sites. The proposed system aiming at detecting road inundation risks had been initially developed and tested in areas of limited size. Its extension to a whole region (the Gard region in the South of France) will be presented, including over 2000 crossing points between rivers and roads and its validation against a large data set of actually reported road inundations observed during recent flash-flood events. These first validation results appear promising. Such a tool would provide the necessary information for flood event management services to identify the areas at risk and to take the appropriate safety and rescue measures: pre-positioning of rescue means, stopping of the traffic on exposed roads, determination of safe accesses or evacuation routes. Moreover, beyond the specific application to the supervision of a road network, this work provides also results concerning the performances of hydro-meteorological forecasts for ungauged headwaters.

  18. The Novel Application of a Spatial Frequency Domain Imaging System to Determine Signature Spectral Differences Between Infected and Non-Infected Burn Wounds

    PubMed Central

    Nguyen, Thu T.A.; Ramella-Roman, Jessica C.; Moffatt, Lauren T.; Ortiz, Rachel T.; Jordan, Marion H.; Shupp, Jeffrey W.

    2012-01-01

    Introduction Complications of infection can increase burn-related morbidity and mortality. Early detection of burn wound infection could lead to more precise and effective treatment, reducing systemic complications and the need for long term, broad-spectrum intravenous antibiotics. Quantitative cultures from biopsies are the gold standard to determine infection. However, this methodology can take days to yield results and is invasive. This investigation focuses on the use of non-invasive imaging to determine the infection status of burn wounds in a controlled in-vivo model. Methods Full-thickness burn wounds were created on the dorsum of adult male rats (n=6). Twenty-four hours after burn wound creation, wounds in the “Infected” group were inoculated with a vehicle containing 1 × 108 CFU Staphylococcus aureus. “Control” group animals received vehicle alone. Subsequently, the wounds were imaged daily for a total of 10 days and the differences of skin optical properties were assessed using a Spatial Frequency Domain Imaging (SFDI) at 16 different wavelengths from 500 nm to 700 nm. Regions of interest on the resulting images were selected and averaged at each time point. Results Statistically significant differences in average absorption and reduced scattering coefficients (?a and ?s’) at 620 and 700 nm were observed between the two groups (p<0.05). Differential optical properties were most evident by day 4 and persisted throughout the time course. Conclusions Differential signature changes in optical properties are evident in infected burn wounds. This novel application of SFDI may prove to be a valuable adjunct to burn wound assessment. Further work will be aimed at determining dose-response relationships and prokaryotic species differences. PMID:23292572

  19. Spatially resolved, laser-induced breakdown spectroscopy, development, and application for the analysis of Al and Si in nickel-based alloys.

    PubMed

    Tsai, Suh-Jen Jane; Chen, Shi-Yang; Chung, Yu-Sheng; Tseng, Pai-Chung

    2006-11-01

    Spatially resolved laser-induced breakdown spectroscopy (SRLIBS) was used for the characterization of aluminum and silicon in nickel-based alloys. The very low invasiveness of the technique was one of the figures of merit of LIBS; however, the relative complexity of the instrument often hindered the widely acceptance of LIBS. Spatially resolved LIBS could provide accuracy and precision comparable to those obtained with temporally resolved LIBS (TRLIBS). In the nongated spatially resolved LIBS, the maximum atomic emission could be obtained with relative low continuum background emission at optimum observation spatial position. The study was done with a Nd:YAG laser at 532 nm, 3.0 mJ laser energy, and 0.2 mbar in argon. The experimental results obtained under optimum conditions were compared to those obtained with TRLIBS. SRLIBS gave reliable results without the tedious optimization of the delay time and gate width. PMID:17073409

  20. Nonparametric regression estimation and prediction for continuous spatial processes

    Microsoft Academic Search

    Sophie Dabo-Niang; Anne-Francoise Yao

    2004-01-01

    The spatial regression estimation as well as prediction is an interesting and crucial problem in statistical inference for a number of applications, where the influence of a vector of covariates on some response variable is to be studied in a context of spatial dependence. Spatial data are modeled as finite realizations of random fields and are collected from dierent spatial

  1. GEO-RBAC: A spatially aware RBAC

    Microsoft Academic Search

    Maria Luisa Damiani; Elisa Bertino; Barbara Catania; Paolo Perlasca

    2007-01-01

    Securing access to data in location-based services and mobile applications requires the definition of spatially aware access-control systems. Even if some approaches have already been proposed either in the context of geographic database systems or context-aware applications, a comprehensive framework, general and flexible enough to deal with spatial aspects in real mobile applications, is still missing. In this paper, we

  2. Theoretical prediction of the source-detector separation distance suited to the application of the spatially resolved spectroscopy from the near-infrared attenuation data cube of tissues

    E-print Network

    Ri, Yong-Wu; Im, Song-Jin

    2014-01-01

    The modified Beer-Lambert law (MBL) and the spatially resolved spectroscopy are used to measure the tissue oxidation in muscles and brains by the continuous wave near-infrared spectroscopy. The spatially resolved spectroscopy predicts the change in the concentration of the absorber by measuring the slope of attenuation data according to the separation and calculating the absorption coefficients of tissue on the basis of the slop in attenuation at the separation distance satisfying the linearity of this slop. This study analyzed the appropriate source-detector separation distance by using the diffuse approximation resolution for photon migration when predicting the absorption coefficient by the spatially resolved spectroscopy on the basis of the reflective image of the tissue. We imagine the 3 dimensional attenuation image with the absorption coefficient, reduced scattering coefficient and separation distance as its axes and obtained the attenuation data cube by calculating the attenuation on a certain interva...

  3. SMART: a spatially explicit bio-economic model for assessing and managing demersal fisheries, with an application to italian trawlers in the strait of sicily.

    PubMed

    Russo, Tommaso; Parisi, Antonio; Garofalo, Germana; Gristina, Michele; Cataudella, Stefano; Fiorentino, Fabio

    2014-01-01

    Management of catches, effort and exploitation pattern are considered the most effective measures to control fishing mortality and ultimately ensure productivity and sustainability of fisheries. Despite the growing concerns about the spatial dimension of fisheries, the distribution of resources and fishing effort in space is seldom considered in assessment and management processes. Here we propose SMART (Spatial MAnagement of demersal Resources for Trawl fisheries), a tool for assessing bio-economic feedback in different management scenarios. SMART combines information from different tasks gathered within the European Data Collection Framework on fisheries and is composed of: 1) spatial models of fishing effort, environmental characteristics and distribution of demersal resources; 2) an Artificial Neural Network which captures the relationships among these aspects in a spatially explicit way and uses them to predict resources abundances; 3) a deterministic module which analyzes the size structure of catches and the associated revenues, according to different spatially-based management scenarios. SMART is applied to demersal fishery in the Strait of Sicily, one of the most productive fisheries of the Mediterranean Sea. Three of the main target species are used as proxies for the whole range exploited by trawlers. After training, SMART is used to evaluate different management scenarios, including spatial closures, using a simulation approach that mimics the recent exploitation patterns. Results evidence good model performance, with a noteworthy coherence and reliability of outputs for the different components. Among others, the main finding is that a partial improvement in resource conditions can be achieved by means of nursery closures, even if the overall fishing effort in the area remains stable. Accordingly, a series of strategically designed areas of trawling closures could significantly improve the resource conditions of demersal fisheries in the Strait of Sicily, also supporting sustainable economic returns for fishermen if not applied simultaneously for different species. PMID:24465971

  4. SMART: A Spatially Explicit Bio-Economic Model for Assessing and Managing Demersal Fisheries, with an Application to Italian Trawlers in the Strait of Sicily

    PubMed Central

    Russo, Tommaso; Parisi, Antonio; Garofalo, Germana; Gristina, Michele; Cataudella, Stefano; Fiorentino, Fabio

    2014-01-01

    Management of catches, effort and exploitation pattern are considered the most effective measures to control fishing mortality and ultimately ensure productivity and sustainability of fisheries. Despite the growing concerns about the spatial dimension of fisheries, the distribution of resources and fishing effort in space is seldom considered in assessment and management processes. Here we propose SMART (Spatial MAnagement of demersal Resources for Trawl fisheries), a tool for assessing bio-economic feedback in different management scenarios. SMART combines information from different tasks gathered within the European Data Collection Framework on fisheries and is composed of: 1) spatial models of fishing effort, environmental characteristics and distribution of demersal resources; 2) an Artificial Neural Network which captures the relationships among these aspects in a spatially explicit way and uses them to predict resources abundances; 3) a deterministic module which analyzes the size structure of catches and the associated revenues, according to different spatially-based management scenarios. SMART is applied to demersal fishery in the Strait of Sicily, one of the most productive fisheries of the Mediterranean Sea. Three of the main target species are used as proxies for the whole range exploited by trawlers. After training, SMART is used to evaluate different management scenarios, including spatial closures, using a simulation approach that mimics the recent exploitation patterns. Results evidence good model performance, with a noteworthy coherence and reliability of outputs for the different components. Among others, the main finding is that a partial improvement in resource conditions can be achieved by means of nursery closures, even if the overall fishing effort in the area remains stable. Accordingly, a series of strategically designed areas of trawling closures could significantly improve the resource conditions of demersal fisheries in the Strait of Sicily, also supporting sustainable economic returns for fishermen if not applied simultaneously for different species. PMID:24465971

  5. Mathematical Modeling of spatial disease variables by Spatial Fuzzy Logic for Spatial Decision Support Systems

    NASA Astrophysics Data System (ADS)

    Platz, M.; Rapp, J.; Groessler, M.; Niehaus, E.; Babu, A.; Soman, B.

    2014-11-01

    A Spatial Decision Support System (SDSS) provides support for decision makers and should not be viewed as replacing human intelligence with machines. Therefore it is reasonable that decision makers are able to use a feature to analyze the provided spatial decision support in detail to crosscheck the digital support of the SDSS with their own expertise. Spatial decision support is based on risk and resource maps in a Geographic Information System (GIS) with relevant layers e.g. environmental, health and socio-economic data. Spatial fuzzy logic allows the representation of spatial properties with a value of truth in the range between 0 and 1. Decision makers can refer to the visualization of the spatial truth of single risk variables of a disease. Spatial fuzzy logic rules that support the allocation of limited resources according to risk can be evaluated with measure theory on topological spaces, which allows to visualize the applicability of this rules as well in a map. Our paper is based on the concept of a spatial fuzzy logic on topological spaces that contributes to the development of an adaptive Early Warning And Response System (EWARS) providing decision support for the current or future spatial distribution of a disease. It supports the decision maker in testing interventions based on available resources and apply risk mitigation strategies and provide guidance tailored to the geo-location of the user via mobile devices. The software component of the system would be based on open source software and the software developed during this project will also be in the open source domain, so that an open community can build on the results and tailor further work to regional or international requirements and constraints. A freely available EWARS Spatial Fuzzy Logic Demo was developed wich enables a user to visualize risk and resource maps based on individual data in several data formats.

  6. A component-based, integrated spatially distributed hydrologic/water quality model: AgroEcoSystem-Watershed (AgES-W) overview and application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AgroEcoSystem-Watershed (AgES-W) is a modular, Java-based spatially distributed model which implements hydrologic/water quality simulation components. The AgES-W model was previously evaluated for streamflow and recently has been enhanced with the addition of nitrogen (N) and sediment modeling compo...

  7. Spatial analysis of bladder, kidney, and pancreatic cancer on upper Cape Cod: an application of generalized additive models to case-control data

    Microsoft Academic Search

    Verónica Vieira; Thomas Webster; Janice Weinberg; Ann Aschengrau

    2009-01-01

    BACKGROUND: In 1988, elevated cancer incidence in upper Cape Cod, Massachusetts prompted a large epidemiological study of nine cancers to investigate possible environmental risk factors. Positive associations were observed, but explained only a portion of the excess cancer incidence. This case-control study provided detailed information on individual-level covariates and residential history that can be spatially analyzed using generalized additive models

  8. Fungus-specific microsatellite primers of lichens: application for the assessment of genetic variation on different spatial scales in Lobaria pulmonaria

    Microsoft Academic Search

    Jean-Claude Walser; Christoph Sperisen; Marco Soliva; Christoph Scheidegger

    2003-01-01

    We isolated 12 microsatellite loci for the epiphytic lichen-forming ascomycete Lobaria pulmonaria and studied their patterns of variation within and among populations from Canada and Switzerland. Even though several microsatellites exhibited high levels of variability at different spatial scales, we did not find any evidence for intrathalline variation. Most of the genetic variation was attributed to differences among individuals within

  9. Geographic Information Systems and Libraries: Patrons, Maps, and Spatial Information. Papers presented at the Clinic on Library Applications of Data Processing (Champaign, Illinois, April 10-12, 1995).

    ERIC Educational Resources Information Center

    Smith, Linda C., Ed.; Gluck, Myke, Ed.

    This document assembles conference papers which focus on how electronic technologies are creating new ways of meeting user needs for spatial and cartographic information. Contents include: (1) "Mapping Technology in Transition" (Mark Monmonier); (2) "Cataloging Planetospatial Data in Digital Form: Old Wine, New Bottles--New Wine, Old Bottles"…

  10. Spatial distribution of Munida intermedia and M. sarsi (crustacea: Anomura) on the Galician continental shelf (NW Spain): Application of geostatistical analysis

    Microsoft Academic Search

    J. Freire; E. González-Gurriarán; I. Olaso

    1992-01-01

    Geostatistical methodology was used to analyse spatial structure and distribution of the epibenthic crustaceans Munida intermedia and M. sarsi within sets of data which had been collected during three survey cruises carried out on the Galician continental shelf (1983 and 1984). This study investigates the feasibility of using geostatistics for data collected according to traditional methods and of enhancing such

  11. Spatial Coverage of Radar Reflectors

    Microsoft Academic Search

    Daniel Levine; William H. Welch

    1964-01-01

    Passive reflectors may be employed to enhance the radar return of a space vehicle for some phases of tracking, as in orbital rendezvous. Contour charts prepared on a suitable base grid provide an objective means of evaluating the spatial coverage of different designs for this application. The superiority of a circular corner reflector over square or triangular designs is demonstrated

  12. Web-based Spatial Information Management Systems

    Microsoft Academic Search

    James Carswell; L. McGeown; J. McMahon

    2002-01-01

    In this paper we discuss the innovative software solutions offered by e-SpatialTM technology for the deployment of web-based and mobile spatial information management systems. This technology has been developed within the Oracle 9i Database environment and allows users to build and deploy spatially enabled Internet applications on any Oracle supported hardware platform and on any device running a Java Virtual

  13. Spatial-Operator Algebra For Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo; Kreutz, Kenneth K.; Milman, Mark H.

    1991-01-01

    Report discusses spatial-operator algebra developed in recent studies of mathematical modeling, control, and design of trajectories of robotic manipulators. Provides succinct representation of mathematically complicated interactions among multiple joints and links of manipulator, thereby relieving analyst of most of tedium of detailed algebraic manipulations. Presents analytical formulation of spatial-operator algebra, describes some specific applications, summarizes current research, and discusses implementation of spatial-operator algebra in the Ada programming language.

  14. Geostatistical modeling of the spatial distribution of soil dioxins in the vicinity of an incinerator. 1. Theory and application to Midland, Michigan.

    PubMed

    Goovaerts, Pierre; Trinh, Hoa T; Demond, Avery; Franzblau, Alfred; Garabrant, David; Gillespie, Brenda; Lepkowski, James; Adriaens, Peter

    2008-05-15

    Deposition of pollutants around point sources of contamination, such as incinerators, can display complex spatial patterns depending on prevailing weather conditions, the local topography, and the characteristics of the source. Deterministic dispersion models often fail to capture the complexity observed in the field, resulting in uncertain predictions that might hamper subsequent decision-making, such as delineation of areas targeted for additional sampling or remediation. This paper describes a geostatistical simulation-based methodology that combines the detailed process-based modeling of atmospheric deposition from an incinerator with the probabilistic modeling of residual variability of field samples. The approach is used to delineate areas with high levels of dioxin TEQ(DF)-WHO98 (toxic equivalents) around an incinerator, accounting for 53 field data and the output of the EPA Industrial Source Complex (ISC3) dispersion model. The dispersion model explains 43.7% of the variance in the soil TEQ data, whereas the regression residuals are spatially correlated with a range of 776 m. One hundred realizations of soil TEQ values are simulated on a grid with a 50 m spacing. The benefit of stochastic simulation over spatial interpolation is 2-fold: (1) maps of simulated point TEQ values can easily be aggregated to the geography that is the most relevant for decision making (e.g., census block, ZIP codes); and (2) the uncertainty at the larger scale is simply modeled by the empirical distribution of block-averaged simulated values. Incorporating the output of the atmospheric deposition model as a spatial trend yields a more realistic prediction of the spatial distribution of TEQ values than log-normal kriging using only the field data, in particular, in sparsely sampled areas away from the incinerator. The geostatistical model provided guidance for the study design (census block-based population sampling) of the University of Michigan Dioxin Exposure Study (UMDES), focused on quantifying exposure pathways to dioxins from industrial sources, relative to background exposures. PMID:18546703

  15. A Bayesian mixed shrinkage prior procedure for spatial-stochastic basis selection and evaluation of gPC expansions: Applications to elliptic SPDEs

    NASA Astrophysics Data System (ADS)

    Karagiannis, Georgios; Konomi, Bledar A.; Lin, Guang

    2015-03-01

    We propose a new fully Bayesian method to efficiently obtain the spectral representation of a spatial random field, which can conduct spatial-stochastic basis selection and evaluation of generalized Polynomial Chaos (gPC) expansions when the number of the available basis functions is significantly larger than the size of the training data-set. We develop a fully Bayesian stochastic procedure, called mixed shrinkage prior (MSP), which performs both basis selection and coefficient evaluation simultaneously. MSP involves assigning a prior probability to the gPC structure and assigning conjugate priors to the expansion coefficients that can be thought of as mixtures of Ridge-LASSO shrinkage priors, in augmented form. The method offers a number of advantages over existing compressive sensing methods in gPC literature, such that it recovers possible sparse structures in both stochastic and spatial domains while the resulting expansion can be re-used directly to economically obtain results at any spatial input values. Yet, it inherits all the advantages of Bayesian model uncertainty methods, e.g. accounts for uncertainty about basis significance and provides interval estimation through posterior distributions. A unique highlight of the MSP procedure is that it can address heterogeneous sparsity in the spatial domain for different random dimensions. Furthermore, it yields a compromise between Ridge and LASSO regressions, and hence combines a weak (l2-norm) and strong (l1-norm) shrinkage, in an adaptive, data-driven manner. We demonstrate the good performance of the proposed method, and compare it against other existing compressive sensing ones on elliptic stochastic partial differential equations.

  16. Spatial Encounters: Exercises in Spatial Awareness.

    ERIC Educational Resources Information Center

    New Mexico Univ., Albuquerque.

    This series of activities on spatial relationships was designed to help users acquire the skills of spatial visualization and orientation and to improve their effectiveness in applying those skills. The series contains an introduction to spatial orientation with several self-directed activities to help improve that skill. It also contains seven…

  17. Qualitative Spatial Reasoning for Topological Map Learning

    Microsoft Academic Search

    Jan Oliver Wallgrün

    2010-01-01

    In this paper we investigate the application of qualitative spatial reasoning methods for learning the topological map of an unknown environment. We develop a topological mapping framework that achieves robustness against ambiguity in the available information by tracking all possible graph hypotheses simultaneously. We then exploit spatial reasoning to reduce the space of possible hypotheses. The considered constraints are qualitative

  18. Building Analysis from a Spatial Cognition Perspective

    E-print Network

    Building Analysis from a Spatial Cognition Perspective Georg Vrachliotis 1 , Christoph Hölscher 2 on the application of concepts and methods of Spatial Cognition to building analysis. We investigate the close comments and behavioral data. Based on an empirical study in a complex multi-level-building two main aspect

  19. Combination of remote sensing data products to derive spatial climatologies of "degree days" and downscale meteorological reanalyses: application to the Upper Indus Basin

    NASA Astrophysics Data System (ADS)

    Forsythe, N. D.; Rutter, N.; Brock, B. W.; Fowler, H. J.; Blenkinsop, S.

    2014-12-01

    Lack of observations for the full range of required variables is a critical reason why many cryosphere-dominated hydrological modelling studies adopt a temperature index (degree day) approach to meltwater simulation rather than resolving the full surface energy balance. Thus spatial observations of "degree days" would be extremely useful in constraining model parameterisations. Even for models implementing a full energy balance, "degree day" observations provide a characterisation of the spatial distribution of climate inputs to the cryosphere-hydrological system. This study derives "degree days" for the Upper Indus Basin by merging remote sensing data products: snow cover duration (SCD), from MOD10A1 and land surface temperature (LST), from MOD11A1 and MYD11A1. Pixel-wise "degree days" are calculated, at imagery-dependent spatial resolution, by multiplying SCD by (above-freezing) daily LST. This is coherent with the snowpack-energy-to-runoff conversion used in temperature index algorithms. This allows assessment of the spatial variability of mass inputs (accumulated snowpack) because in nival regime areas - where complete ablation is regularly achieved - mass is the limiting constraint. The GLIMS Randolph Glacier Inventory is used to compare annual totals and seasonal timings of "degree days" over glaciated and nival zones. Terrain-classified statistics (by elevation and aspect) for the MODIS "degree-day" hybrid product are calculated to characterise of spatial precipitation distribution. While MODIS data products provide detailed spatial resolution relative to tributary catchment areas, the limited instrument record length is inadequate for assessing climatic trends and greatly limits use for hydrological model calibration and validation. While multi-decadal MODIS equivalent data products may be developed in the coming years, at present alternative methods are required for "degree day" trend analysis. This study thus investigates the use of the hybrid MODIS "degree day" product to downscale an ensemble of modern global meteorological reanalyses including ERA-Interim, NCEP CFSR, NASA MERRA and JRA-55 which overlap MODIS instrument record. This downscaling feasibility assessment is a prerequisite to applying the method to regional climate projections.

  20. Spatial Thinking Strategies

    NSDL National Science Digital Library

    Susan Everett

    2000-04-01

    While some people consider spatial thinking a "gift" that only some individuals have, many others view spatial thinking as a cognitive process that can be developed. Much research supports the developmental view of spatial thinking as a cognitive process,

  1. Large-Scale Polysilicon Surface Micro-Machined Spatial Light Modulator Clara Dimas

    E-print Network

    . Keywords : spatial light modulators, micro mirrors, actuator frequency response DESIGN ApplicationsLarge-Scale Polysilicon Surface Micro-Machined Spatial Light Modulator Clara Dimas , Julie, high resolution, phase-only microelectromechanical system (MEMS) spatial light modulator (SLM) has been

  2. Spatially modulated light detector in CMOS with sense-amplifier receiver operating at 180 Mb\\/s for optical data link applications and parallel optical interconnects between chips

    Microsoft Academic Search

    Maarten Kuijk; D. Coppee; R. Vounckx

    1998-01-01

    We present a first realization of a detector receiver combination based on the spatially modulated light detector (SML-detector). The SML-detector gives an output signal that has a shorter falling edge than that of a conventional CMOS detector. It is combined with a sense-amplifier in a standard 0.8-?m CMOS technology, allowing one to receive over 155-Mb\\/s of light pulses at 5.6-?W

  3. Multiscale comparison of spatial patterns using two-dimensional cross-spectral analysis: application to a semi-arid (gapped) landscape

    Microsoft Academic Search

    Nicolas Barbier; Pierre Couteron; Olivier Planchon; Abdoulaye Diouf

    2010-01-01

    Spectral analysis allows the characterization of temporal (1D) or spatial (2D) patterns in terms of their scale (frequency)\\u000a distribution. Cross-spectral analysis can also be used to conduct independent correlation analyses at different scales between\\u000a two variables, even in the presence of a complex superposition of structures, such as structures that are shifted, have different\\u000a scales or have different levels of

  4. Spatial analysis of lung, colorectal, and breast cancer on Cape Cod: An application of generalized additive models to case-control data

    Microsoft Academic Search

    Verónica Vieira; Thomas Webster; Janice Weinberg; Ann Aschengrau; David Ozonoff

    2005-01-01

    BACKGROUND: The availability of geographic information from cancer and birth defect registries has increased public demands for investigation of perceived disease clusters. Many neighborhood-level cluster investigations are methodologically problematic, while maps made from registry data often ignore latency and many known risk factors. Population-based case-control and cohort studies provide a stronger foundation for spatial epidemiology because potential confounders and disease

  5. A geostatistical framework for quantifying the reach-scale spatial structure of river morphology: 2. Application to restored and natural channels

    NASA Astrophysics Data System (ADS)

    Legleiter, Carl J.

    2014-01-01

    Alluvial rivers are shaped by interactions between the bed topography, the flow field, and the movement of sediment. To help refine our understanding of these connections between form and process, I developed a geostatistical framework for quantifying the reach-scale spatial structure of river morphology, described in a companion paper. In this study, I applied this approach to a restored channel and three disparate reaches of a dynamic, natural stream. Repeat topographic surveys of each site were used to examine relationships between channel change and the variability and organization of the topography. For the restored river, the development of point bars increased overall morphologic diversity, primarily because of greater cross-sectional asymmetry. The three natural reaches experienced a variety of adjustments ranging from 1) gradual bar growth and bank erosion to; 2) extensive deposition followed by channel abandonment; and 3) chute cutoff and incision of a new channel. In both the restored and natural streams, geostatistical analysis, which involved variogram modeling, calculation of integral metrics, and inspection of variogram maps, provided an effective, informative summary of the observed channel changes. The use of dimensionless variables accounted for channel size, highlighted differences in spatial structure, and enabled a comparison among sites — the restored reach had not yet achieved the same degree of heterogeneity as the more pristine channels. Emphasizing variability and spatial pattern via this geostatistical framework could yield insight on form-process interactions and help to quantify geomorphic complexity and habitat heterogeneity in the applied context of river restoration.

  6. State-constrained optimal spatial field control for controlled release in tissue engineering

    Microsoft Academic Search

    Masako Kishida; Daniel W. Pack; Richard D. Braatz

    2010-01-01

    Distributed parameter control problems involving manipulation within the spatial domain arise in a variety of applications including vibration control, active noise reduction, epidemiology, tissue engineering, and cancer treatment. A state-constrained spatial field control problem motivated by a biomedical application is solved in which the manipulation occurs over a spatial field and the state field is constrained both in spatial frequency

  7. Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrw B. (Inventor)

    2010-01-01

    The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image. or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image . Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer. SSO. Some embodiments include masking functions. window functions. special treatment for images lying on or near border and pre-processing of test images.

  8. Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B. (Inventor)

    2012-01-01

    The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image, or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image. Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer, SSO. Some embodiments include masking functions, window functions, special treatment for images lying on or near borders and pre-processing of test images.

  9. THE SPATIAL AND TEMPORAL DISTRIBUTION OF CHLORPYRIFOS IN THE U.S. EPA INDOOR AIR QUALITY (IAQ) TEST HOUSE FOLLOWING CRACK AND CREVICE TYPE APPLICATIONS

    EPA Science Inventory

    Pesticides found in homes may result from indoor applications to control household pests or by translocation from outdoor sources. Pesticides disperse according to their physical properties and other factors such as human activity, air exchange, temperature and humidity. Insect...

  10. Application of composite water quality identification index on the water quality evaluation in spatial and temporal variations: a case study in Honghu Lake, China.

    PubMed

    Ban, Xuan; Wu, Qiuzhen; Pan, Baozhu; Du, Yun; Feng, Qi

    2014-07-01

    Composite Water Quality Identification Index (CWQII) and multivariate statistical techniques were used to investigate the temporal and spatial variations of water quality in Honghu Lake. The aims are to explore the characteristics of water quality trends in annual, monthly, and site spatial distribution and to identify the main pollution factors. The results showed that the values of CWQII increased from 2.0 to 4.0 from the years 2001 to 2005, then decreased from 2006 and kept a balance between 2.0 and 3.0 from 2006 to 2011, indicating that the water quality of Honghu Lake deteriorated from 2001 to 2005 and has gradually improved since 2006, which were likely achieved after water protection measurements taken since 2004. The monthly change rules of water quality were influenced by a superposition of natural processes and human activities. In samples numbered 1-9 from upstream to downstream, the maximum values of CWQII often occurred in sample site 9 while the minimum ones often occurred in sample site 2, indicating that the water quality near the upstream tributary was the poorest and that in the core zone was the best. Incoming water from the trunk canal of the Sihu area upstream was the largest pollution source. The sensitive pollution nutrients were mainly caused by the total nitrogen, followed by the total phosphorus. PMID:24615690

  11. GIS technology and spatial analysis in coastal zone management

    Microsoft Academic Search

    Kurt Fedra; Enrico Feoli

    1998-01-01

    This paper reviews methods and tools of spatial analysis, their integration and application to coastal zone management. Following a definition of the coastal zone and a short description of its peculiarities and unique management problems, the paper first describes the major tools for spatial analysis, and in particular, GIS and remote sensing, spatially distributed simulation modeling and optimization, and expert

  12. Optimal spatial field control of distributed parameter systems

    Microsoft Academic Search

    Masako Kishida; Richard D. Braatz

    2009-01-01

    Optimal control problems are formulated and solved in which the manipulation is distributed over a three-dimensional (3D) spatial field with constraints on the spatial variation. These spatial field control problems that arise in applications in acoustics, structures, epidemiology, cancer treatment, and tissue engineering have much higher controllability than boundary control problems, but have vastly higher degrees of freedom. Efficient algorithms

  13. Policy applications of a highly resolved spatial and temporal onroad carbon dioxide emissions data product for the U.S.: Analyses and their implications for mitigation

    NASA Astrophysics Data System (ADS)

    Mendoza Lebrun, Daniel

    Onroad CO2 emissions were analyzed as part of overall GHG emissions, but those studies have suffered from one or more of these five shortcomings: 1) the spatial resolution was coarse, usually encompassing a region, or the entire U.S.; 2) the temporal resolution was coarse (annual or monthly); 3) the study region was limited, usually a metropolitan planning organization (MPO) or state; 4) fuel sales were used as a proxy to quantify fuel consumption instead of focusing on travel; 5) the spatial heterogeneity of fleet and road network composition was not considered and instead national averages are used. Normalized vehicle-type state-level spatial biases range from 2.6% to 8.1%, while the road type classification biases range from -6.3% to 16.8%. These biases are found to cause errors in reduction estimates as large as ±60%, corresponding to ±0.2 MtC, for a national-average emissions mitigation strategy focused on a 10% emissions reduction from a single vehicle class. Temporal analysis shows distinct emissions seasonality that is particularly visible in the northernmost latitudes, demonstrating peak-to-peak deviations from the annual mean of up to 50%. The hourly structure shows peak-to-peak deviation from a weekly average of up to 200% for heavy-duty (HD) vehicles and 140% for light-duty (LD) vehicles. The present study focuses on reduction of travel and fuel economy improvements by putting forth several mitigation scenarios aimed at reducing VMT and increasing vehicle fuel efficiency. It was found that the most effective independent reduction strategies are those that increase fuel efficiency by extending standards proposed by the corporate average fuel economy (CAFE) or reduction of fuel consumption due to price increases. These two strategies show cumulative emissions reductions of approximately 11% and 12%, respectively, from a business as usual (BAU) approach over the 2000-2050 period. The U.S. onroad transportation sector is long overdue a comprehensive study of CO2 emissions at a highly resolved level. Such a study would improve fossil fuel flux products by enhancing measurement accuracy and prompt location-specific mitigation policy. The carbon cycle science and policymaking communities are both poised to benefit greatly from the development of a highly resolved spatiotemporal emissions product.

  14. Delineating high-density areas in spatial Poisson fields from strip-transect sampling using indicator geostatistics: application to unexploded ordnance removal.

    PubMed

    Saito, Hirotaka; McKenna, Sean A

    2007-07-01

    An approach for delineating high anomaly density areas within a mixture of two or more spatial Poisson fields based on limited sample data collected along strip transects was developed. All sampled anomalies were transformed to anomaly count data and indicator kriging was used to estimate the probability of exceeding a threshold value derived from the cdf of the background homogeneous Poisson field. The threshold value was determined so that the delineation of high-density areas was optimized. Additionally, a low-pass filter was applied to the transect data to enhance such segmentation. Example calculations were completed using a controlled military model site, in which accurate delineation of clusters of unexploded ordnance (UXO) was required for site cleanup. PMID:16824672

  15. Fungus-specific microsatellite primers of lichens: application for the assessment of genetic variation on different spatial scales in Lobaria pulmonaria.

    PubMed

    Walser, Jean-Claude; Sperisen, Christoph; Soliva, Marco; Scheidegger, Christoph

    2003-10-01

    We isolated 12 microsatellite loci for the epiphytic lichen-forming ascomycete Lobaria pulmonaria and studied their patterns of variation within and among populations from Canada and Switzerland. Even though several microsatellites exhibited high levels of variability at different spatial scales, we did not find any evidence for intrathalline variation. Most of the genetic variation was attributed to differences among individuals within populations. High genetic variation was also detected among L. pulmonaria samples taken from individual trees, suggesting that either multiple colonization events had occurred or that local recombination is frequent. The geographically structured distribution of alleles from several microsatellites indicated that L. pulmonaria from Canada and Switzerland represent two distinct evolutionary lineages. The potential to identify multiple alleles, and their transferability to closely related species, make microsatellites an ideal tool to study dispersal, population differentiation, and microevolution in lichens. PMID:12948515

  16. Spatially correlated underwater acoustic multiple-input and multiple-output channel model and its application to estimation of channel capacity

    NASA Astrophysics Data System (ADS)

    Kim, Joonsuk; Koh, Il-Suek; Lee, Yongshik

    2015-07-01

    In this paper, we present a multiple-input and multiple-output (MIMO) channel signal model for underwater acoustic communication systems. This model uses the ray-tracing method to obtain the deterministic part of a channel signal, whereas the fluctuating part is obtained on the basis of the scattering coefficient of the time-varying ocean surface. For the accurate estimation of the channel capacity, spatial correlation is considered during channel signal generation. The validity of the proposed model is verified by comparing it with known ideal solutions. Moreover, results obtained from experimental data are provided to support the proposed model. MIMO channel signals generated by the model can be used to estimate the channel capacity in various communication scenarios.

  17. Application of global positioning system methods for the study of obesity and hypertension risk among low-income housing residents in New York City: a spatial feasibility study.

    PubMed

    Duncan, Dustin T; Regan, Seann D; Shelley, Donna; Day, Kristen; Ruff, Ryan R; Al-Bayan, Maliyhah; Elbel, Brian

    2014-11-01

    The purpose of this study was to evaluate the feasibility of using global positioning system (GPS) methods to understand the spatial context of obesity and hypertension risk among a sample of low-income housing residents in New York City (n = 120). GPS feasibility among participants was measured with a pre- and post-survey as well as adherence to a protocol which included returning the GPS device as well as objective data analysed from the GPS devices. We also conducted qualitative interviews with 21 of the participants. Most of the sample was overweight (26.7%) or obese (40.0%). Almost one-third (30.8%) was pre-hypertensive and 39.2% was hypertensive. Participants reported high ratings of GPS acceptability, ease of use and low levels of wear-related concerns in addition to few concerns related to safety, loss or appearance, which were maintained after the baseline GPS feasibility data collection. Results show that GPS feasibility increased over time. The overall GPS return rate was 95.6%. Out of the total of 114 participants with GPS, 112 (98.2%) delivered at least one hour of GPS data for one day and 84 (73.7%) delivered at least one hour on 7 or more days. The qualitative interviews indicated that overall, participants enjoyed wearing the GPS devices, that they were easy to use and charge and that they generally forgot about the GPS device when wearing it daily. Findings demonstrate that GPS devices may be used in spatial epidemiology research in low-income and potentially other key vulnerable populations to understand geospatial determinants of obesity, hypertension and other diseases that these populations disproportionately experience. PMID:25545926

  18. Part II: temporal and spatial distribution of multiclass pesticide residues in lake sediments of northern Greece: application of an optimized MAE-LC-MS/MS pretreatment and analytical method.

    PubMed

    Kalogridi, Eleni-Chrysoula; Christophoridis, Christophoros; Bizani, Erasmia; Drimaropoulou, Garyfallia; Fytianos, Konstantinos

    2014-06-01

    The development and application of an analytical methodology for the pretreatment and determination of 253 multiclass pesticides, in lake sediment samples, using liquid chromatography coupled with mass spectrometry (LC-MS/MS) are described in this work. Sediments of lakes Volvi, Doirani, and Kerkini, located in northern Greece, were collected in two-time periods (fall/winter 2010 and spring/summer 2011) and analyzed, applying the developed analytical methodology. Microwave-assisted extraction (MAE) was applied to extract the pesticide residues from lake sediment samples. Analytical results were stored, categorized, and visualized using geographical information systems, in order to assess and observe spatial and temporal variations of the pollution. Main pesticides that were detected included the following: amitrole, tebuconazole, phoxim, diniconazole, sethoxydim, temephos, tetrachlorvinphos, pendimethalin, boscalid, disulfoton sulfone, lenacil, propiconazole, cycloxydim, pyridaben, and terbuthylazine. Amitrole, diniconazole, and tebuconazole were found to be common in all three lakes. Lakes Kerkini and Doirani exhibited increased concentrations during the first sampling period (winter 2010) with predominant pesticide classes, triazines/triazoles and organophosphates. Pollution is mainly located near the populated villages of the lakes and the nearby cultivations. During the second sampling period, pesticide concentrations appear lower and located in sediments near the center of the lake. Lake Volvi exhibits increased pesticide concentrations during the second sampling period, temporal and spatial variations and different pesticide profile pattern. Increased pollution occurs near the center of the lake during the first sampling period, mainly comprised by triazines/triazoles and organophosphates. During the second sampling period, the majority of the sediment samples demonstrated a different pesticide profile dominated by unclassified pesticides and triazines/triazoles. Mineralogical analysis of the samples demonstrates that sediments are mainly composed of clay, mud, and sand particles, and they present spatial variations. Near the center of the lakes, sediments appear to be more fine-grained with higher clay content and are more likely to adsorb pesticides. PMID:24691934

  19. Oracle Spatial Data Option Spatial Cartridge Oracle8i SpatialIBM ESRI DB2 Spatial ExtenderInformix Informix Spatial

    E-print Network

    Li, Xiang

    ; ---- Oracle Spatial Data Option Spatial Cartridge Oracle8i SpatialIBM ESRI DB2 Spatial ExtenderInformix Informix Spatial Datablade Oracle Oracle8i Spatial Oracle Spatial ----SDO_GEOMETRY SDO_GEOMETRY Oracle/cdrom/papers/coors1997 Oracle Co.Oracle Spatial White Paper2001.5 MapInfo Co. Spatial Database Standards

  20. Spatial Solitons in Algaas Waveguides

    NASA Astrophysics Data System (ADS)

    Kang, Jin Ung

    In this work, by measuring the two-, three-photon absorption, and the nonlinear refractive index coefficients, a useful bandwidth for an all-optical switching applications in the AlGaAs below half the band gap is identified. Operating in this material system, several types of spatial solitons such as fundamental bright solitons, Vector solitons, and Manakov solitons are experimentally demonstrated. The propagation and the interaction behaviors of these solitons are studied experimentally and numerically. The distinct properties of each soliton are discussed along with some possible applications. Some applications, such as all -optical switching based on spatial soliton dragging and the efficient guiding of orthogonally polarized femtosecond pulses by a bright spatial soliton, are experimentally demonstrated. The signal gain due to an ultrafast polarization coupling, better known as Four Wave Mixing (FWM) is demonstrated in a channel waveguide. The effects of FWM are studied experimentally and numerically. This effect is also used to demonstrate polarization switching. The linear and nonlinear properties of AlGaAs/GaAs multiple quantum well waveguides are measured. Anisotropic two photon absorption and nonlinear refractive indices near half the band gap are measured along with the linear birefringence for several different quantum well structures. The usefulness of multiple quantum well structures for an all -optical switching because of anisotropic nature of this material system is discussed.

  1. Breeding habitat preferences of 15 bird species on south-western Finnish archipelago coast: Applicability of digital spatial data archives to habitat assessment

    Microsoft Academic Search

    Mia Rönkä; Harri Tolvanen; Esa Lehikoinen; Mikael von Numers; Mauri Rautkari

    2008-01-01

    Knowledge about the importance of physical habitat characteristics to the breeding site selection of birds is a prerequisite for understanding their breeding habitat ecology and distribution, as well as managing their habitats. Geographical information systems (GIS) and existing digital data archives provide new possibilities for the quantitative and cost-effective assessment of coastal breeding habitats of birds. We tested the applicability

  2. Improvement in spatial resolution of background-oriented schlieren technique by introducing a telecentric optical system and its application to supersonic flow

    NASA Astrophysics Data System (ADS)

    Ota, Masanori; Leopold, Friedrich; Noda, Ryusuke; Maeno, Kazuo

    2015-03-01

    A telecentric optical system is applied to the background-oriented schlieren (BOS) technique to improve accuracy, overcoming the drawbacks of conventional diverging light observation. This paper describes the optical arrangement and formula for telecentric BOS measurement and presents measurement results obtained by the colored-grid background-oriented schlieren technique to confirm the theoretical prediction. The application of the new approach for a large-scale supersonic wind tunnel test is reported.

  3. Assessment of the water self-purification capacity on a river affected by organic pollution: application of chemometrics in spatial and temporal variations.

    PubMed

    González, S Oliva; Almeida, C A; Calderón, M; Mallea, M A; González, P

    2014-09-01

    Water pollution caused by organic matter is a major global problem which requires continuous evaluation. Multivariate statistical analysis was applied to assess spatial and temporal changes caused by natural and anthropogenic phenomena along Potrero de los Funes River. Cluster analysis (CA), principal component analysis (PCA) and analysis of variance (ANOVA) were applied to a data set collected throughout a period of 3 years (2010-2012), which monitored 22 physical, chemical and biological parameters. Content of dissolved oxygen in water and biochemical oxygen demand in a watercourse are indicators of pollution caused by organic matter. For this reason, the Streeter-Phelps model was used to evaluate the water self-purification capacity. Hierarchical cluster analysis grouped the sampling sites based on the similarity of water quality characteristics. PCA resulted in two latent factors explaining 75.2 and 17.6 % of the total variance in water quality data sets. Multidimensional ANOVA suggested that organic pollution is mainly due to domestic wastewater run-offs and anthropogenic influence as a consequence of increasing urbanization and tourist influx over the last years. Besides, Streeter-Phelps parameters showed a low reaeration capacity before dam with low concentration of dissolved oxygen. Furthermore, self-purification capacity loss was correlated with the decrease of the Benthic Index. This measurement suggested that biological samplings complement the physical-chemical analysis of water quality. PMID:24888622

  4. Measurements of the temporal and spatial phase variations of a 33 GHz pulsed free electron laser amplifier and application to high gradient RF acceleration

    SciTech Connect

    Volfbeyn, P.; Bekefi, G. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-12-31

    We report the results of temporal and spatial measurements of phase of a pulsed free electron laser amplifier (FEL) operating in combined wiggler and axial guide magnetic fields. The 33 GHz FEL is driven by a mildly relativistic electron beam (750 kV, 90-300 A, 30 ns) and generates 61 MW of radiation with a high power magnetron as the input source. The phase is measured by an interferometric technique from which frequency shifting is determined. The results are simulated with a computer code. Experimental studies on a CERN-CLIC 32.98 GHz 26-cell high gradient accelerating section (HGA) were carried out for input powers from 0.1 MW to 35 MW. The FEL served as the r.f. power source for the HGA. The maximum power in the transmitted pulse was measured to be 15 MW for an input pulse of 35 MW. The theoretically calculated shunt impedance of 116 M{Omega}/m predicts a field gradient of 65 MeV/m inside the HGA. For power levels >3MW the pulse transmitted through the HGA was observed to be shorter than the input pulse and pulse shortening became more serious with increasing power input. At the highest power levels the output pulse length (about 5 nsec) was about one quarter of the input pulse length. Various tests suggest that these undesirable effects occur in the input coupler to the HGA. Light and X-ray production inside the HGA have been observed.

  5. Analysing urban resilience through alternative stormwater management options: application of the conceptual Spatial Decision Support System model at the neighbourhood scale.

    PubMed

    Balsells, M; Barroca, B; Amdal, J R; Diab, Y; Becue, V; Serre, D

    2013-01-01

    Recent changes in cities and their environments, caused by rapid urbanisation and climate change, have increased both flood probability and the severity of flooding. Consequently, there is a need for all cities to adapt to climate and socio-economic changes by developing new strategies for flood risk management. Following a risk paradigm shift from traditional to more integrated approaches, and considering the uncertainties of future urban development, one of the main emerging tasks for city managers becomes the development of resilient cities. However, the meaning of the resilience concept and its operability is still not clear. The goal of this research is to study how urban engineering and design disciplines can improve resilience to floods in urban neighbourhoods. This paper presents the conceptual Spatial Decision Support System (DS3) model which we consider a relevant tool to analyse and then implement resilience into neighbourhood design. Using this model, we analyse and discuss alternative stormwater management options at the neighbourhood scale in two specific areas: Rotterdam and New Orleans. The results obtained demonstrate that the DS3 model confirmed in its framework analysis that stormwater management systems can positively contribute to the improved flood resilience of a neighbourhood. PMID:24334895

  6. Modeling persistent organic pollutant (POP) partitioning between tree bark and air and its application to spatial monitoring of atmospheric POPs in mainland China.

    PubMed

    Zhao, Yuli; Yang, Limin; Wang, Qiuquan

    2008-08-15

    A mathematical model describing the bark/air partitioning of persistent organic pollutants (POPs) was established taking into consideration the accumulation processes of POPs from air into bark and compound-, species-, and site-specific air-to-bark accumulation factors. It allows the assessment of the concentrations of atmospheric POPs based on those recorded in tree bark. The spatial distribution of atmospheric POPs including 18 polycyclic aromatic hydrocarbons (Sigma18PAHs), 5 organic chlorinated pesticides (Sigma5OCPs), 10 polychlorinated biphenyls (Sigma10PCBs), and 17 brominated flame retardants (Sigma17BFRs) were investigated by analyzing 163 bark samples from 68 sites across mainland China. The atmospheric POPs were estimated to be 4.1-399 ng/m3 air, and 11.3-553, 4.5-130, and 0.9-624 pg/m3 air with geometric means of 71 ng/m3 air, and 99,26, and 25 pg/m3 airfor Sigma18PAHs, Sigma5OCPs, Sigma10PCBs, and Sigma17BFRs, respectively, based on those recorded in the tree barks of 5.1-1770, 0.05-12.9, 0.21-21.6, and 0.02-48.3 ng/g bark on dry weight basis, with geometric means of 295, 1.47, 3.12, and 2.79 ng/g bark. These results generally indicated that contamination by atmospheric POPs is more serious in eastern and mid China than that in western China. PMID:18767664

  7. Development and application of methods to quantify spatial and temporal hyperpolarized 3He MRI ventilation dynamics: preliminary results in chronic obstructive pulmonary disease

    NASA Astrophysics Data System (ADS)

    Kirby, Miranda; Wheatley, Andrew; McCormack, David G.; Parraga, Grace

    2010-03-01

    Hyperpolarized helium-3 (3He) magnetic resonance imaging (MRI) has emerged as a non-invasive research method for quantifying lung structural and functional changes, enabling direct visualization in vivo at high spatial and temporal resolution. Here we described the development of methods for quantifying ventilation dynamics in response to salbutamol in Chronic Obstructive Pulmonary Disease (COPD). Whole body 3.0 Tesla Excite 12.0 MRI system was used to obtain multi-slice coronal images acquired immediately after subjects inhaled hyperpolarized 3He gas. Ventilated volume (VV), ventilation defect volume (VDV) and thoracic cavity volume (TCV) were recorded following segmentation of 3He and 1H images respectively, and used to calculate percent ventilated volume (PVV) and ventilation defect percent (VDP). Manual segmentation and Otsu thresholding were significantly correlated for VV (r=.82, p=.001), VDV (r=.87 p=.0002), PVV (r=.85, p=.0005), and VDP (r=.85, p=.0005). The level of agreement between these segmentation methods was also evaluated using Bland-Altman analysis and this showed that manual segmentation was consistently higher for VV (Mean=.22 L, SD=.05) and consistently lower for VDV (Mean=-.13, SD=.05) measurements than Otsu thresholding. To automate the quantification of newly ventilated pixels (NVp) post-bronchodilator, we used translation, rotation, and scaling transformations to register pre-and post-salbutamol images. There was a significant correlation between NVp and VDV (r=-.94 p=.005) and between percent newly ventilated pixels (PNVp) and VDP (r=- .89, p=.02), but not for VV or PVV. Evaluation of 3He MRI ventilation dynamics using Otsu thresholding and landmark-based image registration provides a way to regionally quantify functional changes in COPD subjects after treatment with beta-agonist bronchodilators, a common COPD and asthma therapy.

  8. Application of a spatially distributed water balance model for assessing surface water and groundwater resources in the Geba basin, Tigray, Ethiopia

    NASA Astrophysics Data System (ADS)

    Gebreyohannes, Tesfamichael; De Smedt, Florimond; Walraevens, Kristine; Gebresilassie, Solomon; Hussien, Abdelwasie; Hagos, Miruts; Amare, Kasa; Deckers, Jozef; Gebrehiwot, Kindeya

    2013-08-01

    The Geba basin is one of the most water-stressed areas of Ethiopia, with only a short rainy period from mid-June to mid-September. Because rainfall in this region has been consistently erratic in the last decades, both in time and space, rain-fed agriculture has become problematic. Hence, in order to supplement rain-fed agriculture by irrigation, a detailed understanding of local and regional surface water and groundwater resources is important. The main objective of this study is to assess the available water resources in the Geba basin using a spatially distributed water balance model (WetSpass). Relevant input data for the model is prepared in the form of digital maps using remote sensing images, GIS tools, FAO and NASA databases, field reconnaissance and processing of meteorological and hydrological observations. The model produces digital maps of long-term average, seasonal and annual surface runoff, evapotranspiration and groundwater recharge. Results of the model show that 76% of the precipitation in the basin is lost through evapotranspiration, 18% becomes surface runoff and only 6% recharges the groundwater system. Model predictions are verified against river flow observations and are shown to be reliable. Additional maps are derived of accumulated surface runoff, safe yield for groundwater abstraction and water deficit for crop growth. Comparison of existing reservoirs with the accumulated runoff map shows that many reservoirs have failed because their design capacity is much higher than the actual inflow. Comparison of the safe yield map with the crop water deficit map shows that in most areas groundwater can be safely abstracted to supplement the water deficit for crop growth during the wet summer season. However, in the dry winter season the crop water deficit is too high to be supplemented by groundwater abstraction in a sustainable way.

  9. Qualitative vs. Fuzzy Represenations of Spatial Distance

    Microsoft Academic Search

    Daniel Hernández

    1997-01-01

    Fuzzy set theory is a well-established modeling tool with applications in many domains, one of them being spatial reasoning.\\u000a Qualitative approaches to the representation of spatial knowledge, by contrast, have become increasingly popular only in the\\u000a last five years. In this paper, we compare fuzzy and qualitative approaches to the representation of the distance between\\u000a two entities in physical space.

  10. High-spatial-resolution remote sensing

    Microsoft Academic Search

    Tomas Brandtberg; Timothy Warner

    Recent developments in high-spatial-resolution remote sensing have created a wide array of potential new forestry applications. High spatial resolution imagery allows a tree-scale of analysis, in which individual trees and their attributes are the focus of interest. This tree-scale remote sensing contrasts with the traditional community-scale remote sensing of medium resolution sensors such as Landsat. A variety of approaches have

  11. Solving Large-scale Spatial Optimization Problems in Water Resources Management through Spatial Evolutionary Algorithms

    NASA Astrophysics Data System (ADS)

    Wang, J.; Cai, X.

    2007-12-01

    A water resources system can be defined as a large-scale spatial system, within which distributed ecological system interacts with the stream network and ground water system. Water resources management, the causative factors and hence the solutions to be developed have a significant spatial dimension. This motivates a modeling analysis of water resources management within a spatial analytical framework, where data is usually geo- referenced and in the form of a map. One of the important functions of Geographic information systems (GIS) is to identify spatial patterns of environmental variables. The role of spatial patterns in water resources management has been well established in the literature particularly regarding how to design better spatial patterns for satisfying the designated objectives of water resources management. Evolutionary algorithms (EA) have been demonstrated to be successful in solving complex optimization models for water resources management due to its flexibility to incorporate complex simulation models in the optimal search procedure. The idea of combining GIS and EA motivates the development and application of spatial evolutionary algorithms (SEA). SEA assimilates spatial information into EA, and even changes the representation and operators of EA. In an EA used for water resources management, the mathematical optimization model should be modified to account the spatial patterns; however, spatial patterns are usually implicit, and it is difficult to impose appropriate patterns to spatial data. Also it is difficult to express complex spatial patterns by explicit constraints included in the EA. The GIS can help identify the spatial linkages and correlations based on the spatial knowledge of the problem. These linkages are incorporated in the fitness function for the preference of the compatible vegetation distribution. Unlike a regular GA for spatial models, the SEA employs a special hierarchical hyper-population and spatial genetic operators to represent spatial variables in a more efficient way. The hyper-population consists of a set of populations, which correspond to the spatial distributions of the individual agents (organisms). Furthermore spatial crossover and mutation operators are designed in accordance with the tree representation and then applied to both organisms and populations. This study applies the SEA to a specific problem of water resources management- maximizing the riparian vegetation coverage in accordance with the distributed groundwater system in an arid region. The vegetation coverage is impacted greatly by the nonlinear feedbacks and interactions between vegetation and groundwater and the spatial variability of groundwater. The SEA is applied to search for an optimal vegetation configuration compatible to the groundwater flow. The results from this example demonstrate the effectiveness of the SEA. Extension of the algorithm for other water resources management problems is discussed.

  12. Spatial profiling using a Time of Flight Diagnostic and applications of deuterim-deuterium fusion in Inertial Electrostatic Confinement fusion devices

    NASA Astrophysics Data System (ADS)

    Donovan, David C.

    2011-12-01

    The Inertial Electrostatic Confinement (IEC) Fusion Research Group at the University of Wisconsin-Madison utilizes IEC devices as small-scale neutron generators using D-D fusion to create 2.45 MeV neutrons for the purpose of detecting clandestine material. Detection of explosives in particular can be accomplished using thermal neutron capture methods to identify characteristic nitrogen signatures in explosive material. Research has been conducted to increase reliability of detection, decrease interrogation time, and increase the steady-state operational time. Efforts have also been made to increase the neutron production rate of the device. Optimization studies have varied the configuration and design of the electrodes and have resulted in system configurations with up to 50 percent higher neutron production rates than have previously been utilized. A new feedthrough design has been constructed that is intended to increase the maximum operating voltage from 175 kV with the previous feedthrough to 300 kV. Neutron production rates scale almost linearly with both current and voltage, so the IEC device will be capable of operation at higher neutron producing regimes than have ever before been achieved. The optimization efforts involve the use of several new diagnostic tools developed at UW, which are the Fusion Ion Doppler (FIDO) Diagnostic and the Time of Flight (TOF) Diagnostic. FIDO provides the energy spectra of the charged fusion products and reactants created in the IEC device. The FIDO Diagnostic was originally only capable of studying D-D fusion, but with recent advancements is now able to study both D-D and D-3He fusion. The TOF Diagnostic provides spatial information along with the energy resolution of where the fusion reactions are occurring in the IEC device. Development of the diagnostics has involved the implementation of timing electronics, alignment systems, data acquisition software, computational post-processing, and upgrades to the experimental facility. A significant rise in the concentration of fusion events was found outside of the anode, believed to be due in part from negative ions. The FIDO and TOF Diagnostics have proven to be valuable additions to the study of IEC devices and have greatly advanced IEC operation and theory.

  13. Application of thermal analysis to measure the spatial heterogeneity of organic matter degradation after wildfire: implications for post-fire rehabilitation treatments

    NASA Astrophysics Data System (ADS)

    Merino, Agustin; Fonturbel, M. Teresa; Vega, Jose A.

    2015-04-01

    Severe wildfires can cause drastic changes in SOM content and quality with important implications for soil conservation and global C balance. Soil heating usually leads to loss of the most labile SOM compounds (e.g. carbohydrates, lipids and peptides) and to generation of aromatic substances. However, these fire-related damages are not uniform over large areas, because of the spatial heterogeneity of different factors such as fire type and environmental conditions. Rapid diagnosis of soil burn severity is required to enable the design of emergency post-fire rehabilitation treatments. The study was conducted in soils from NW Spain, an Atlantic-climate zone that is particularly prone to wildfires. Intact soil cores (forest floor and uppermost mineral soil layer) were taken from a soil developed under granitic rock and subjected to experimental burning (in a bench positioned at the outlet of a wind tunnel). Soil temperature during fire was monitorised and five visual levels of soil burn severity (SBS) were recorded immediately after fire. Solid-state 13C CP-MAS NMR spectroscopy analyses were performed in an Agilent (Varian) VNMRS-500-WB spectrometer. The samples were analyzed by differential scanning calorimetry and thermogravimetry (TGA/DSC, Mettler-Toledo Intl. Inc.). The analyses were performed with 4 mg of samples placed in open aluminium pans under dry air (flow rate, 50 mL?1) and at a scanning rate of 10 °C min?1. The temperature ranged between 50 and 600 °C. In the organic layer, the temperature reached during fire influenced the formation and characteristics of charred material. These materials showed an increasing degree of carbonization/aromatization in relation to the increase of temperature during burning. Burning also led to compounds of higher thermal recalcitrance (increases in T50 values -the temperature at which 50% of the energy stored in SOM is released-). However, values recorded in some samples were lower than those measured in highly polycondensed aromatic compounds. In the mineral soil, large reductions in SOM content were found in both moderate and high SBS (up to 70 %), whereas important effects on SOM quality were only associated with high SBS. NMR analysis revealed these changes as losses of O-alkyl, alkyl and carboxylic structures and increases of the aromatic structures (up to 50 %). In both organic and mineral soils the DSC analysis revealed decreased combustion heat released up to 375 °C, and increased T50. Relationships between thermal properties and chemical-shift regions in the NMR helped provide a better understanding of SOM quality after wildfire. The results also show that thermal analysis can be used as a rapid tool to assess the different degrees of SOM degradation, in areas where the complex heterogeneity of the fire damage requires different emergency post-fire rehabilitation treatments.

  14. Application of Spatial Data Modeling and Geographical Information Systems (GIS) for Identification of Potential Siting Options for Various Electrical Generation Sources

    SciTech Connect

    Mays, Gary T [ORNL; Belles, Randy [ORNL; Blevins, Brandon R [ORNL; Hadley, Stanton W [ORNL; Harrison, Thomas J [ORNL; Jochem, Warren C [ORNL; Neish, Bradley S [ORNL; Omitaomu, Olufemi A [ORNL; Rose, Amy N [ORNL

    2012-05-01

    Oak Ridge National Laboratory (ORNL) initiated an internal National Electric Generation Siting Study, which is an ongoing multiphase study addressing several key questions related to our national electrical energy supply. This effort has led to the development of a tool, OR-SAGE (Oak Ridge Siting Analysis for power Generation Expansion), to support siting evaluations. The objective in developing OR-SAGE was to use industry-accepted approaches and/or develop appropriate criteria for screening sites and employ an array of Geographic Information Systems (GIS) data sources at ORNL to identify candidate areas for a power generation technology application. The initial phase of the study examined nuclear power generation. These early nuclear phase results were shared with staff from the Electric Power Research Institute (EPRI), which formed the genesis and support for an expansion of the work to several other power generation forms, including advanced coal with carbon capture and storage (CCS), solar, and compressed air energy storage (CAES). Wind generation was not included in this scope of work for EPRI. The OR-SAGE tool is essentially a dynamic visualization database. The results shown in this report represent a single static set of results using a specific set of input parameters. In this case, the GIS input parameters were optimized to support an economic study conducted by EPRI. A single set of individual results should not be construed as an ultimate energy solution, since US energy policy is very complex. However, the strength of the OR-SAGE tool is that numerous alternative scenarios can be quickly generated to provide additional insight into electrical generation or other GIS-based applications. The screening process divides the contiguous United States into 100 x 100 m (1-hectare) squares (cells), applying successive power generation-appropriate site selection and evaluation criteria (SSEC) to each cell. There are just under 700 million cells representing the contiguous United States. If a cell meets the requirements of each criterion, the cell is deemed a candidate area for siting a specific power generation form relative to a reference plant for that power type. Some SSEC parameters preclude siting a power plant because of an environmental, regulatory, or land-use constraint. Other SSEC assist in identifying less favorable areas, such as proximity to hazardous operations. All of the selected SSEC tend to recommend against sites. The focus of the ORNL electrical generation source siting study is on identifying candidate areas from which potential sites might be selected, stopping short of performing any detailed site evaluations or comparisons. This approach is designed to quickly screen for and characterize candidate areas. Critical assumptions supporting this work include the supply of cooling water to thermoelectric power generation; a methodology to provide an adequate siting footprint for typical power plant applications; a methodology to estimate thermoelectric plant capacity while accounting for available cooling water; and a methodology to account for future ({approx}2035) siting limitations as population increases and demands on freshwater sources change. OR-SAGE algorithms were built to account for these critical assumptions. Stream flow is the primary thermoelectric plant cooling source evaluated in this study. All cooling was assumed to be provided by a closed-cycle cooling (CCC) system requiring makeup water to account for evaporation and blowdown. Limited evaluations of shoreline cooling and the use of municipal processed water (gray) cooling were performed. Using a representative set of SSEC as input to the OR-SAGE tool and employing the accompanying critical assumptions, independent results for the various power generation sources studied were calculated.

  15. Parcellating connectivity in spatial maps

    PubMed Central

    Beck, Diane M.; Fei-Fei, Li

    2015-01-01

    A common goal in biological sciences is to model a complex web of connections using a small number of interacting units. We present a general approach for dividing up elements in a spatial map based on their connectivity properties, allowing for the discovery of local regions underlying large-scale connectivity matrices. Our method is specifically designed to respect spatial layout and identify locally-connected clusters, corresponding to plausible coherent units such as strings of adjacent DNA base pairs, subregions of the brain, animal communities, or geographic ecosystems. Instead of using approximate greedy clustering, our nonparametric Bayesian model infers a precise parcellation using collapsed Gibbs sampling. We utilize an infinite clustering prior that intrinsically incorporates spatial constraints, allowing the model to search directly in the space of spatially-coherent parcellations. After showing results on synthetic datasets, we apply our method to both functional and structural connectivity data from the human brain. We find that our parcellation is substantially more effective than previous approaches at summarizing the brain’s connectivity structure using a small number of clusters, produces better generalization to individual subject data, and reveals functional parcels related to known retinotopic maps in visual cortex. Additionally, we demonstrate the generality of our method by applying the same model to human migration data within the United States. This analysis reveals that migration behavior is generally influenced by state borders, but also identifies regional communities which cut across state lines. Our parcellation approach has a wide range of potential applications in understanding the spatial structure of complex biological networks. PMID:25737822

  16. Toward intelligent spatial information dissemination based on user profile model

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Zhu, Xinyan; Zhang, Chunlin; He, Jie

    2008-12-01

    Spatial information dissemination is a necessary step to make use of spatial information for which is a bridge between the acquirement and the application of spatial information. However, conventional methods of spatial information dissemination cannot cater to users in that not only users' personalized requirements cannot be satisfied, but initiative dissemination service cannot be provided. In this paper, the idea of intelligent spatial information dissemination (ISD) is proposed. Combining the ideas of personalized information retrieval, information filtering and recommender systems, the ISD system employs user profiles and query conditions to provide two implement ways of spatial information disseminations, namely "pull" and "push". Then, the three layers architecture of intelligent spatial information dissemination system based on user profile model is given, and the procedure of data in the ISD system is introduced. Also, the user profile is presented including user profile model and user profile management. Finally, the prototype system of intelligent spatial information dissemination is presented.

  17. Approach to spatial information security based on digital certificate

    NASA Astrophysics Data System (ADS)

    Cong, Shengri; Zhang, Kai; Chen, Baowen

    2005-11-01

    With the development of the online applications of geographic information systems (GIS) and the spatial information services, the spatial information security becomes more important. This work introduced digital certificates and authorization schemes into GIS to protect the crucial spatial information combining the techniques of the role-based access control (RBAC), the public key infrastructure (PKI) and the privilege management infrastructure (PMI). We investigated the spatial information granularity suited for sensitivity marking and digital certificate model that fits the need of GIS security based on the semantics analysis of spatial information. It implements a secure, flexible, fine-grained data access based on public technologies in GIS in the world.

  18. Spatial cointegration and heteroscedasticity

    NASA Astrophysics Data System (ADS)

    Lauridsen, Jørgen; Kosfeld, Reinhold

    2007-09-01

    A two-step Lagrange Multiplier test strategy has recently been suggested as a tool to reveal spatial cointegration. The present paper generalises the test procedure by incorporating control for unobserved heteroscedasticity. Using Monte Carlo simulation, the behaviour of several relevant tests for spatial cointegration and/or heteroscedasticity is investigated. The two-step test for spatial cointegration appears to be robust towards heteroscedasticity. While several tests for heteroscedasticity prove to be inconclusive under certain circumstances, a Lagrange Multiplier test for heteroscedasticity based on spatially differenced variables is shown to serve well as an indication of heteroscedasticity irrespective of cointegration status.

  19. Minimising Mortality in Endangered Raptors Due to Power Lines: The Importance of Spatial Aggregation to Optimize the Application of Mitigation Measures

    PubMed Central

    Guil, Francisco; Fernández-Olalla, Mariana; Moreno-Opo, Rubén; Mosqueda, Ignacio; Gómez, María Elena; Aranda, Antonio; Arredondo, Ángel; Guzmán, José; Oria, Javier; González, Luis Mariano; Margalida, Antoni

    2011-01-01

    Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators. PMID:22140549

  20. Minimising mortality in endangered raptors due to power lines: the importance of spatial aggregation to optimize the application of mitigation measures.

    PubMed

    Guil, Francisco; Fernández-Olalla, Mariana; Moreno-Opo, Rubén; Mosqueda, Ignacio; Gómez, María Elena; Aranda, Antonio; Arredondo, Angel; Guzmán, José; Oria, Javier; González, Luis Mariano; Margalida, Antoni

    2011-01-01

    Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators. PMID:22140549

  1. Individual Differences in Spatial Text Processing: High Spatial Ability Can Compensate for Spatial Working Memory Interference

    ERIC Educational Resources Information Center

    Meneghetti, Chiara; Gyselinck, Valerie; Pazzaglia, Francesca; De Beni, Rossana

    2009-01-01

    The present study investigates the relation between spatial ability and visuo-spatial and verbal working memory in spatial text processing. In two experiments, participants listened to a spatial text (Experiments 1 and 2) and a non-spatial text (Experiment 1), at the same time performing a spatial or a verbal concurrent task, or no secondary task.…

  2. Community Invasibility Spatial Heterogeneity, Spatial Scale,

    E-print Network

    Davies, Kendi

    . Davies, University of Colorado, Boulder IntroDuCtIon: Why Are Some CommunItIeS more InvASIble thAn other, serpentine systems are very spatially heterogeneous in soil chemistry, texture, rockiness, and toxicity empirical studies that detected negative relation- ships between native and exotic diversity at small

  3. Curriculum in Spatial Sciences

    E-print Network

    Curriculum in Spatial Sciences Catalog 12-13 University Core Curriculum Required Courses (Th-Pr) Cr.......................................................................................(3-0) 3 Mathematics electives (MATH prefix required) 1...............................................................................................................(3-2) 4 40 #12;Spatial Sciences Core Curriculum ESSM 444 Remote Sensing of the Environment

  4. SPATIAL ENCRYPTION A DISSERTATION

    E-print Network

    SPATIAL ENCRYPTION A DISSERTATION SUBMITTED TO THE DEPARTMENT OF COMPUTER SCIENCE AND THE COMMITTEE cryptography and guide my study of it, he also worked directly on spatial encryption. Finally, the credit and Generic Groups . . . . . . . . . . . . . . . . . . 9 2 Generalized Identity-Based Encryption 11 2

  5. SPATIAL INTERACTION DATA

    Microsoft Academic Search

    Derek Thompson

    1974-01-01

    The lack of good flow data is a handicap to spatial interaction researth, yet many published works provide little evaluation of such data. Good quality flow data should provide spatial coverage at a large scale with small sampling and other error components. Few generally available data series for interregional commodity flows, interregional population migration, and intercity person movement in the

  6. Architectural Implications for Spatial Object Association Algorithms*

    PubMed Central

    Kumar, Vijay S.; Kurc, Tahsin; Saltz, Joel; Abdulla, Ghaleb; Kohn, Scott R.; Matarazzo, Celeste

    2013-01-01

    Spatial object association, also referred to as crossmatch of spatial datasets, is the problem of identifying and comparing objects in two or more datasets based on their positions in a common spatial coordinate system. In this work, we evaluate two crossmatch algorithms that are used for astronomical sky surveys, on the following database system architecture configurations: (1) Netezza Performance Server®, a parallel database system with active disk style processing capabilities, (2) MySQL Cluster, a high-throughput network database system, and (3) a hybrid configuration consisting of a collection of independent database system instances with data replication support. Our evaluation provides insights about how architectural characteristics of these systems affect the performance of the spatial crossmatch algorithms. We conducted our study using real use-case scenarios borrowed from a large-scale astronomy application known as the Large Synoptic Survey Telescope (LSST). PMID:25692244

  7. A spatial light modulator for terahertz beams

    SciTech Connect

    Chen, Hou-tong [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory

    2009-01-01

    Spatial light modulators that control the spatial transmission of a terahertz beam either electrically or optically, have been difficult to build due to the lack of suitable materials. Here we propose the use of active terahertz metamaterials for the construction of a multi-pixel spatial modulator for terahertz beams. Our first-generation device consists of a 4 x 4 pixel array, where each pixel is an array of sub-wavelength-sized split-ring resonator elements fabricated on a semiconductor substrate, and is independently controlled by applying an external voltage. Through terahertz transmission experiments, we show that the spatial modulator has a uniform modulation depth of around 40 percent across all pixels at the resonant frequency. Around this operating frequency, the crosstalk between pixels is negligible. This device can operate under small voltage levels, at room temperature, with low power consumption and reasonably high switching speed, and can therefore benefit future applications in terahertz imaging and communications.

  8. Architectural Implications for Spatial Object Association Algorithms

    SciTech Connect

    Kumar, V S; Kurc, T; Saltz, J; Abdulla, G; Kohn, S R; Matarazzo, C

    2009-01-29

    Spatial object association, also referred to as cross-match of spatial datasets, is the problem of identifying and comparing objects in two or more datasets based on their positions in a common spatial coordinate system. In this work, we evaluate two crossmatch algorithms that are used for astronomical sky surveys, on the following database system architecture configurations: (1) Netezza Performance Server R, a parallel database system with active disk style processing capabilities, (2) MySQL Cluster, a high-throughput network database system, and (3) a hybrid configuration consisting of a collection of independent database system instances with data replication support. Our evaluation provides insights about how architectural characteristics of these systems affect the performance of the spatial crossmatch algorithms. We conducted our study using real use-case scenarios borrowed from a large-scale astronomy application known as the Large Synoptic Survey Telescope (LSST).

  9. Spatial filters for complex wavefront modulation.

    PubMed

    Sarkadi, Tamás; Kettinger, Ádám; Koppa, Pál

    2013-08-01

    In this paper we propose a method to generate independent and simultaneous phase and amplitude modulation by a phase-only spatial light modulator and Fourier filtering. The incident light is modulated by a suitable phase pattern containing high spatial frequencies. The modulated light is transmitted through a 4f optical system having an appropriate spatial filter in the Fourier plane in order to synthesize the expected complex modulated wavefront on the output of the system. We propose a simple method to generate spatial filters applicable for the phase-only to complex modulated wavefront conversion. We analyze the quality of the output image related to the ideal wavefront using the proposed filters. We show that more efficient complex modulation can be realized by the proposed method than by the earlier solutions. PMID:23913064

  10. Entropy, complexity, and spatial information.

    PubMed

    Batty, Michael; Morphet, Robin; Masucci, Paolo; Stanilov, Kiril

    2014-01-01

    We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon's (in Bell Syst Tech J 27:379-423, 623-656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events-more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems. PMID:25309123

  11. Children's Spatial Thinking: Does Talk about the Spatial World Matter?

    ERIC Educational Resources Information Center

    Pruden, Shannon M.; Levine, Susan C.; Huttenlocher, Janellen

    2011-01-01

    In this paper we examine the relations between parent spatial language input, children's own production of spatial language, and children's later spatial abilities. Using a longitudinal study design, we coded the use of spatial language (i.e. words describing the spatial features and properties of objects; e.g. big, tall, circle, curvy, edge) from…

  12. Crop growth and soil water spatial variability under a variable rate center pivot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture has mostly emphasized variable-rate nutrients, seeding, and pesticide applications. More recently, variable-rate irrigation equipment has been developed to explore the potential for managing irrigation spatially. Managing irrigation spatially can enhance water conservation and ...

  13. Spatial phase dislocations in femtosecond laser pulses

    E-print Network

    Dreischuh, Alexander

    -generated holograms, provided that they are built in a setup compensating for the intro- duced spatial dispersion with a screw-type phase distribution is associated with an optical vortex (OV). The characteristic helical14 and soliton algebra.15­19 All types of soliton application will benefit from ultrashort pulses

  14. Spatial Modelling of New Zealand Temperature Normals

    Microsoft Academic Search

    Xiaogu Zheng; Reid E. Basher

    1996-01-01

    Spatial modelling and prediction of normals of monthly temperatures in relation to geographical factors is examined for a data set of 100 New Zealand climate stations, most of which have 30-year records. Results are given for maximum and minimum temperature and for mean temperature and diurnal range. Latitude and altitude are well established as predictors of temperature. The application of

  15. Attribute uncertainty modelling in lunar spatial data

    Microsoft Academic Search

    P. Weiss; Wen-Zhong Shi; Kai-Leung Yung

    2010-01-01

    A novel methodology to evaluate uncertainties in lunar elemental abundances is presented. Contrary to most terrestrial applications, lunar geographic information system (GIS) data cannot be verified by in situ measurements because of the limited number of ground control points and their reduced spatial extent. This work reports on investigations to evaluate the uncertainty in lunar abundance measurements without the use of

  16. Spatial Computing in MGS Antoine Spicher1

    E-print Network

    are involved in computer aided design applications, geo- graphic databases, image processing. . . to cite a few-order effect that we have to make explicit in programs, to use, produce or optimize. 1.1 Spatial Computer developing cell's behavior is controlled only by its local chemical and physical environment

  17. Old movie restoration using rational spatial interpolators

    Microsoft Academic Search

    L. Khriji; M. Gabbouj; G. Ramponi; E. Decenciere Ferrandiere

    1999-01-01

    The restoration of old movies using the newly developed rational functions filters is considered. After localization of the stationary and random defects, a spatial rational interpolator scheme is proposed to reconstruct the missing data. The experimental results demonstrate the usefulness of the rational interpolator in an application involving the restoration of defects in old movies. The resulting edges obtained using

  18. Microscopic Origin of Spatial Coherence and Wolf Shifts

    E-print Network

    Girish S. Agarwal

    2003-11-13

    We show that the vacuum of electromagnetic field has intrinsic partial spatial coherence in frequency domain which effectively extends over regions of the order of wavelength $\\lambda$. This spatial coherence leads to a dynamical coupling between atoms and is the cause of source correlations and Wolf shifts. We show how the source spatial correlations can lead to tailor made coherent emissions. We discuss the universality of source correlation effects and presents several application.

  19. Robustness of spatial micronetworks.

    PubMed

    McAndrew, Thomas C; Danforth, Christopher M; Bagrow, James P

    2015-04-01

    Power lines, roadways, pipelines, and other physical infrastructure are critical to modern society. These structures may be viewed as spatial networks where geographic distances play a role in the functionality and construction cost of links. Traditionally, studies of network robustness have primarily considered the connectedness of large, random networks. Yet for spatial infrastructure, physical distances must also play a role in network robustness. Understanding the robustness of small spatial networks is particularly important with the increasing interest in microgrids, i.e., small-area distributed power grids that are well suited to using renewable energy resources. We study the random failures of links in small networks where functionality depends on both spatial distance and topological connectedness. By introducing a percolation model where the failure of each link is proportional to its spatial length, we find that when failures depend on spatial distances, networks are more fragile than expected. Accounting for spatial effects in both construction and robustness is important for designing efficient microgrids and other network infrastructure. PMID:25974553

  20. Robustness of spatial micronetworks

    NASA Astrophysics Data System (ADS)

    McAndrew, Thomas C.; Danforth, Christopher M.; Bagrow, James P.

    2015-04-01

    Power lines, roadways, pipelines, and other physical infrastructure are critical to modern society. These structures may be viewed as spatial networks where geographic distances play a role in the functionality and construction cost of links. Traditionally, studies of network robustness have primarily considered the connectedness of large, random networks. Yet for spatial infrastructure, physical distances must also play a role in network robustness. Understanding the robustness of small spatial networks is particularly important with the increasing interest in microgrids, i.e., small-area distributed power grids that are well suited to using renewable energy resources. We study the random failures of links in small networks where functionality depends on both spatial distance and topological connectedness. By introducing a percolation model where the failure of each link is proportional to its spatial length, we find that when failures depend on spatial distances, networks are more fragile than expected. Accounting for spatial effects in both construction and robustness is important for designing efficient microgrids and other network infrastructure.

  1. View-based access control mechanism for spatial database

    NASA Astrophysics Data System (ADS)

    Lin, Jiayuan; Fang, Yu; Chen, Bin; Wan, Lin

    2008-12-01

    The development and application of spatial database ultimately create the demand for spatial information security, and access control is our primary concern. The access control requirements for spatial database contain two special aspects: 1) fine-grained; 2) meeting certain conditions, including spatial and non-spatial. In this paper, we propose a view-based mechanism to implement access control functionalities. We firstly present the authorization model for spatial data. Then we thoroughly discuss the definition of various views and their authorization, and explain the advantages and disadvantages of this model. We also provide a reference framework for the view-based access control system, and the components and control flow are explained. Finally, we use a case study to demonstrate the feasibility and effectiveness of view-based authorization model for securing spatial database access.

  2. Spatial reconstruction of single-cell gene expression data.

    PubMed

    Satija, Rahul; Farrell, Jeffrey A; Gennert, David; Schier, Alexander F; Regev, Aviv

    2015-05-01

    Spatial localization is a key determinant of cellular fate and behavior, but methods for spatially resolved, transcriptome-wide gene expression profiling across complex tissues are lacking. RNA staining methods assay only a small number of transcripts, whereas single-cell RNA-seq, which measures global gene expression, separates cells from their native spatial context. Here we present Seurat, a computational strategy to infer cellular localization by integrating single-cell RNA-seq data with in situ RNA patterns. We applied Seurat to spatially map 851 single cells from dissociated zebrafish (Danio rerio) embryos and generated a transcriptome-wide map of spatial patterning. We confirmed Seurat's accuracy using several experimental approaches, then used the strategy to identify a set of archetypal expression patterns and spatial markers. Seurat correctly localizes rare subpopulations, accurately mapping both spatially restricted and scattered groups. Seurat will be applicable to mapping cellular localization within complex patterned tissues in diverse systems. PMID:25867923

  3. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  4. Spatial multiple instance learning for hyperspectral image analysis

    Microsoft Academic Search

    Jeremy Bolton; Paul Gader

    2010-01-01

    Standard multiple instance learning (MIL) techniques are capable of learning when there is a lack of target information (including size, shape, and even location); however, this is attained at the cost of the utility of spatial information. This is unfortunate because in many image analysis applications, there is a substantial amount of observable spatial information. The research presented in the

  5. Modeling and estimating the spatial distribution of healthcare workers

    Microsoft Academic Search

    Donald Ephraim Curtis; Christopher S. Hlady; Sriram V. Pemmaraju; Philip M. Polgreen; Alberto Maria Segre

    2010-01-01

    This paper describes a spatial model for healthcare workers' location in a large hospital facility. Such models have many applications in healthcare, such as supporting time-and- motion efficiency studies to improve healthcare delivery, or modeling the spread of hospital-acquired infections. We use our model to estimate spatial distributions for healthcare workers in The University of Iowa Hospitals and Clinics (UIHC),

  6. Single Snapshot Spatial Smoothing With Improved Effective Array Aperture

    Microsoft Academic Search

    Arpita Thakre; Martin Haardt; K. Giridhar

    2009-01-01

    Spatial smoothing is a widely used preprocessing scheme for direction-of-arrival (DOA) estimation of more than one source from a single snapshot, although the effective array aperture gets reduced by this process. In this paper we propose a preprocessing scheme applicable for DOA estimation algorithms that exploit the shift invariance property of the array steering matrix and call it spatial smoothing

  7. Spatial Frequency Response of Acrylamide Based Holographic Photopolymer

    Microsoft Academic Search

    Raghavendra Jallapuram; Izabela Naydenova; Vincent Toal; Suzanne Martin; Robert Howard

    2003-01-01

    It has been shown that photopolymers are useful in holographic optical elements [1] and holographic interferometry [2]. However, the list of potential applications increases greatly if reflection holography is possible. Reflection holography requires a material that has the potential to record high spatial frequencies. Here we studied the spatial frequency response of an acrylamide based dye sensitized holographic photopolymer. We

  8. Spatial Query Processing in Wireless Sensor Networks - A Survey

    Microsoft Academic Search

    Rone Ilídio da Silva; Daniel Fernandes Macedo; José Marcos S. Nogueira

    2012-01-01

    Wireless sensor networks (WSN) are particularly useful for obtaining data concerning events limited to a well-defined geographic region, such as a disaster site or a malfunctioning subsection of a factory plant. Such applications tipically use spatial queries, which are SQL-like queries where location constraints are imposed on the collected data. Further, spatial queries allow changing the set of nodes (the

  9. Covariance Tapering for Interpolation of Large Spatial Datasets

    E-print Network

    Genton, Marc G.

    Covariance Tapering for Interpolation of Large Spatial Datasets Reinhard FURRER, Marc G. GENTON results. An application to a large climatological precipitation dataset is presented as a concrete-based methods make it possible to analyze and fit large spatial datasets in a high level Reinhard Furrer

  10. Proximal soil sensing to parameterize spatial environmental modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatially explicit models are important tools to understand the effects of the interaction of management and landscape factors on water and soil quality. One challenge to application of such models is the need to know spatially-distributed values for input parameters. Some such data can come from av...

  11. Genetic K-Medoids Spatial Clustering with Obstacles Constraints

    Microsoft Academic Search

    Xueping Zhang; Jiayao Wang; Fang Wu; Zhongshan Fan; Wenbo Xu

    2006-01-01

    Spatial clustering is an important research topic in spatial data mining (SDM). It is not only an important effective method but also a prelude of other task for SDM. Grouping similar data in large 2-dimensional spaces to find hidden patterns or meaningful sub-groups has many applications such as satellite imagery, geographic information systems, medical image analysis, marketing, computer visions, etc.

  12. R-trees: a dynamic index structure for spatial searching

    Microsoft Academic Search

    Antonin Guttman

    1984-01-01

    In order to handle spatial data efficiently, as required in computer aided design and geo-data applications, a database system needs an mdex mechanism that ti help it retrieve data items quickly accordmg to their spatial locations However, traditional mdexmg methods are not well suited to data oblects of non-zero size located m multidimensional spaces In this paper we describe a

  13. QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL

    E-print Network

    Grunwald, Sabine

    QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL I. Chaubey, C. T. Haan OF RAINFALL1 1. Chaubey, C. T Haan, J. M. Salisbury, and S. Grunwald2 ABSTRACT: Traditionally in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous

  14. Grounding language in spatial routines

    E-print Network

    Tellex, Stefanie, 1980-

    2006-01-01

    This thesis describes a spatial language understanding system based on a lexicon of words defined in terms of spatial routines. A spatial routine is a script composed from a set of primitive operations on sensor data, ...

  15. ET Spatial Techniques

    NSDL National Science Digital Library

    ET Spatial Techniques

    This site from ET Spatial Techniques profiles reasonably priced, highly functional software for the ArcView/ArcGIS professionals. Links to information and free dowloads can also be found on this site.

  16. Spatially Distributed Cell Signalling

    PubMed Central

    Kholodenko, Boris N.

    2009-01-01

    Emerging evidence indicates that complex spatial gradients and (micro)domains of signalling activities arise from distinct cellular localization of opposing enzymes, such as a kinase and phosphatase, in signal transduction cascades. Often, an interacting, active form of a target protein has a lower diffusivity than an inactive form, and this leads to spatial gradients of the protein abundance in the cytoplasm. A spatially distributed signalling cascade can create step-like activation profiles, which decay at successive distances from the cell surface, assigning digital positional information to different regions in the cell. Feedback and feedforward network motifs control activity patterns, allowing signalling networks to serve as cellular devices for spatial computations. PMID:19800332

  17. Spatial Data Supply Chains

    NASA Astrophysics Data System (ADS)

    Varadharajulu, P.; Azeem Saqiq, M.; Yu, F.; McMeekin, D. A.; West, G.; Arnold, L.; Moncrieff, S.

    2015-06-01

    This paper describes current research into the supply of spatial data to the end user in as close to real time as possible via the World Wide Web. The Spatial Data Infrastructure paradigm has been discussed since the early 1990s. The concept has evolved significantly since then but has almost always examined data from the perspective of the supplier. It has been a supplier driven focus rather than a user driven focus. The current research being conducted is making a paradigm shift and looking at the supply of spatial data as a supply chain, similar to a manufacturing supply chain in which users play a significant part. A comprehensive consultation process took place within Australia and New Zealand incorporating a large number of stakeholders. Three research projects that have arisen from this consultation process are examining Spatial Data Supply Chains within Australia and New Zealand and are discussed within this paper.

  18. Mapping spatial relations

    E-print Network

    Kasturirangan, Rajesh, 1971-

    2004-01-01

    One of the fundamental issues in cognitive science is the problem of grounding concepts in the perceptual world. In this thesis, I present a computational theory for how spatial relations are grounded in the perceptual ...

  19. Geologic spatial analysis

    SciTech Connect

    Thiessen, R.L.; Eliason, J.R.

    1989-01-01

    This report describes the development of geologic spatial analysis research which focuses on conducting comprehensive three-dimensional analysis of regions using geologic data sets that can be referenced by latitude, longitude, and elevation/depth. (CBS)

  20. Advanced Review Applications of spatial statistical

    E-print Network

    ,7 Colin Sowder,8 E. Ashley Steel,9 Marie-Josee Fortin,10 Chris E. Jordan,11 Aaron S. Ruesch,12 Nicholas the status and trends of stream resources is vital for their effective conser- vation and management. Most

  1. Nonparametric Spatial Prediction

    Microsoft Academic Search

    Gérard Biau; Benoît Cadre

    2004-01-01

    Let (?*)\\u000a N\\u000a be the integer lattice points in the N-dimensional Euclidean space. We define a nonparametric spatial predictor for the values of a random field indexed by (?*)\\u000a N\\u000a using a kernel method. We first examine the general problem of the regression estimation for random fields. Then we show\\u000a the uniform consistency on compact sets of our spatial predictor

  2. Spatially branched hierarchical ZnO nanorod-TiO2 nanotube array heterostructures for versatile photocatalytic and photoelectrocatalytic applications: towards intimate integration of 1D-1D hybrid nanostructures

    NASA Astrophysics Data System (ADS)

    Xiao, Fang-Xing; Hung, Sung-Fu; Tao, Hua Bing; Miao, Jianwei; Yang, Hong Bin; Liu, Bin

    2014-11-01

    Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure-property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron-hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D-1D hybrid nanocomposites for extensive photocatalytic applications.Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure-property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron-hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D-1D hybrid nanocomposites for extensive photocatalytic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04886e

  3. The static gravitational field near spatial infinity I

    NASA Astrophysics Data System (ADS)

    Beig, R.

    1980-06-01

    A static solution to Einstein's equations, which is asymptotically flat near spatial infinity, is shown to be asymptotically Schwarzschildian. As an application of this result we prove a technical lemma on the existence of asymptotically flat harmonic coordinates near infinity.

  4. Understanding the Causes of Spatial Variation in Pesticide Sorption and

    E-print Network

    (bentazone, isoproturon, and glyphosate) in the cultivated soils of an agricultural catchment in Sweden and inorganic sorbents affected glyphosate sorption, but apparently not that of bentazone or isoproturon in large-scale model applications. Keywords: spatial variation, bentazone, isoproturon, glyphosate

  5. 1985 NAPAP EMISSIONS INVENTORY: DEVELOPMENT OF SPATIAL ALLOCATION FACTORS

    EPA Science Inventory

    The report documents the development and application of spatial allocation factors for the 1985 National Acid Precipitation Assessment program(NAPAP) Emissions Inventory (Version 2). The 1985 annual inventory and related modelers' inventory represent the most comprehensive and hi...

  6. Influence-Based Model Decomposition For Reasoning About Spatially Distributed

    E-print Network

    Bailey-Kellogg, Chris

    Influence-Based Model Decomposition For Reasoning About Spatially Distributed Physical Systems important science and engineering applications, such as regulating the tem- perature distribution over a semiconductor wafer and controlling the noise from a photocopy machine, require interpreting distributed data

  7. Reconstructing Spatial Distributions from Anonymized Locations

    SciTech Connect

    Horey, James L [ORNL] [ORNL; Forrest, Stephanie [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Groat, Michael [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque

    2012-01-01

    Devices such as mobile phones, tablets, and sensors are often equipped with GPS that accurately report a person's location. Combined with wireless communication, these devices enable a wide range of new social tools and applications. These same qualities, however, leave location-aware applications vulnerable to privacy violations. This paper introduces the Negative Quad Tree, a privacy protection method for location aware applications. The method is broadly applicable to applications that use spatial density information, such as social applications that measure the popularity of social venues. The method employs a simple anonymization algorithm running on mobile devices, and a more complex reconstruction algorithm on a central server. This strategy is well suited to low-powered mobile devices. The paper analyzes the accuracy of the reconstruction method in a variety of simulated and real-world settings and demonstrates that the method is accurate enough to be used in many real-world scenarios.

  8. Spatial strategies for managing visitor impacts in National Parks

    USGS Publications Warehouse

    Leung, Y.-F.; Marion, J.L.

    1999-01-01

    Resource and social impacts caused by recreationists and tourists have become a management concern in national parks and equivalent protected areas. The need to contain visitor impacts within acceptable limits has prompted park and protected area managers to implement a wide variety of strategies and actions, many of which are spatial in nature. This paper classifies and illustrates the basic spatial strategies for managing visitor impacts in parks and protected areas. A typology of four spatial strategies was proposed based on the recreation and park management literature. Spatial segregation is a common strategy for shielding sensitive resources from visitor impacts or for separating potentially conflicting types of use. Two forms of spatial segregation are zoning and closure. A spatial containment strategy is intended to minimize the aggregate extent of visitor impacts by confining use to limited designated or established Iocations. In contrast, a spatial dispersal strategy seeks to spread visitor use, reducing the frequency of use to levels that avoid or minimize permanent resource impacts or visitor crowding and conflict. Finally, a spatial configuration strategy minimizes impacting visitor behavior though the judicious spatial arrangement of facilities. These four spatial strategics can be implemented separately or in combination at varying spatial scales within a single park. A survey of national park managers provides an empirical example of the diversity of implemented spatial strategies in managing visitor impacts. Spatial segregation is frequently applied in the form of camping restrictions or closures to protect sensitive natural or cultural resources and to separate incompatible visitor activities. Spatial containment is the most widely applied strategy for minimizing the areal extent of resource impacts. Spatial dispersal is commonly applied to reduce visitor crowding or conflicts in popular destination areas but is less frequently applied or effective in minimizing resource impacts. Spatial configuration was only minimally evaluated, as it was not included in the survey. The proposed typology of spatial strategies offers a useful means of organizing and understanding the wide variety of management strategies and actions applied in managing visitor impacts in parks and protected areas. Examples from U.S. national parks demonstrate the diversity of these basic strategies and their flexibility in implementation at various spatial scales. Documentation of these examples helps illustrate their application and inform managers of the multitude of options. Further analysis from the spatial perspective is needed Io extend the applicability of this typology to other recreational activities and management issues.

  9. Making a Place for Space: Spatial Thinking in Social Science

    PubMed Central

    Logan, John R.

    2013-01-01

    New technologies and multilevel data sets that include geographic identifiers have heightened sociologists’ interest in spatial analysis. I review several of the key concepts, measures, and methods that are brought into play in this work, and offer examples of their application in a variety of substantive fields. I argue that the most effective use of the new tools requires greater emphasis on spatial thinking. A device as simple as an illustrative map requires some understanding of how people respond to visual cues; models as complex as HLM with spatial lags require thoughtful measurement decisions and raise questions about what a spatial effect represents. PMID:24273374

  10. Diffusion on spatial network

    NASA Astrophysics Data System (ADS)

    Hui, Zi; Tang, Xiaoyue; Li, Wei; Greneche, Jean-Marc; Wang, Qiuping A.

    2015-04-01

    In this work, we study the problem of diffusing a product (idea, opinion, disease etc.) among agents on spatial network. The network is constructed by random addition of nodes on the planar. The probability for a previous node to be connected to the new one is inversely proportional to their spatial distance to the power of ?. The diffusion rate between two connected nodes is inversely proportional to their spatial distance to the power of ? as well. Inspired from the Fick's first law, we introduce the diffusion coefficient to measure the diffusion ability of the spatial network. Using both theoretical analysis and Monte Carlo simulation, we get the fact that the diffusion coefficient always decreases with the increasing of parameter ? and ?, and the diffusion sub-coefficient follows the power-law of the spatial distance with exponent equals to -?-?+2. Since both short-range diffusion and long-range diffusion exist, we use anomalous diffusion method in diffusion process. We get the fact that the slope index ? in anomalous diffusion is always smaller that 1. The diffusion process in our model is sub-diffusion.

  11. RADSS: an integration of GIS, spatial statistics, and network service for regional data mining

    NASA Astrophysics Data System (ADS)

    Hu, Haitang; Bao, Shuming; Lin, Hui; Zhu, Qing

    2005-10-01

    Regional data mining, which aims at the discovery of knowledge about spatial patterns, clusters or association between regions, has widely applications nowadays in social science, such as sociology, economics, epidemiology, crime, and so on. Many applications in the regional or other social sciences are more concerned with the spatial relationship, rather than the precise geographical location. Based on the spatial continuity rule derived from Tobler's first law of geography: observations at two sites tend to be more similar to each other if the sites are close together than if far apart, spatial statistics, as an important means for spatial data mining, allow the users to extract the interesting and useful information like spatial pattern, spatial structure, spatial association, spatial outlier and spatial interaction, from the vast amount of spatial data or non-spatial data. Therefore, by integrating with the spatial statistical methods, the geographical information systems will become more powerful in gaining further insights into the nature of spatial structure of regional system, and help the researchers to be more careful when selecting appropriate models. However, the lack of such tools holds back the application of spatial data analysis techniques and development of new methods and models (e.g., spatio-temporal models). Herein, we make an attempt to develop such an integrated software and apply it into the complex system analysis for the Poyang Lake Basin. This paper presents a framework for integrating GIS, spatial statistics and network service in regional data mining, as well as their implementation. After discussing the spatial statistics methods involved in regional complex system analysis, we introduce RADSS (Regional Analysis and Decision Support System), our new regional data mining tool, by integrating GIS, spatial statistics and network service. RADSS includes the functions of spatial data visualization, exploratory spatial data analysis, and spatial statistics. The tool also includes some fundamental spatial and non-spatial database in regional population and environment, which can be updated by external database via CD or network. Utilizing this data mining and exploratory analytical tool, the users can easily and quickly analyse the huge mount of the interrelated regional data, and better understand the spatial patterns and trends of the regional development, so as to make a credible and scientific decision. Moreover, it can be used as an educational tool for spatial data analysis and environmental studies. In this paper, we also present a case study on Poyang Lake Basin as an application of the tool and spatial data mining in complex environmental studies. At last, several concluding remarks are discussed.

  12. High Spatial Resolution Remotely Sensed Data for Ecosystem Characterization

    NSDL National Science Digital Library

    MICHAEL A. WULDER, RONALD J. HALL, NICHOLAS C. COOPS, and STEVEN E. FRANKLIN (; )

    2004-06-01

    This peer-reviewed resource from Bioscience magazine presents technical aspects of remote sensing for images at high spatial resolution. Characterization of ecosystem structure, diversity, and function is increasingly desired at finer spatial and temporal scales than have been derived in the past. Many ecological applications require detailed data representing large spatial extents, but these data are often unavailable or are impractical to gather using field-based techniques. Remote sensing offers an option for collecting data that can represent broad spatial extents with detailed attribute characterizations. Remotely sensed data are also appropriate for use in studies across spatial scales, in conjunction with field-collected data. This article presents the pertinent technical aspects of remote sensing for images at high spatial resolution (i.e., with a pixel size of 16 square meters or less), existing and future options for the processing and analysis of remotely sensed data, and attributes that can be estimated with these data for forest ecosystems.

  13. Spatial symmetry breaking in rapidly rotating convective spherical shells

    NASA Technical Reports Server (NTRS)

    Zhang, Keke; Schubert, Gerald

    1995-01-01

    Many problems in geophysical and astrophysical convection systems are characterized by fast rotation and spherical shell geometry. The combined effects of Coriolis forces and spherical shell geometry produce a unique spatial symmetry for the convection pattern in a rapidly rotating spherical shell. In this paper, we first discuss the general spatial symmetries for rotating spherical shell convection. A special model, a spherical shell heated from below, is then used to illustrate how and when the spatial symmetries are broken. Symmetry breaking occurs via a sequence of spatial transitions from the primary conducting state to the complex multiple-layered columnar structure. It is argued that, because of the dominant effects of rotation, the sequence of spatial transitions identified from this particular model is likely to be generally valid. Applications of the spatial symmetry breaking to planetary convection problems are also discussed.

  14. Embodied spatial cognition.

    PubMed

    Trafton, J Gregory; Harrison, Anthony M

    2011-10-01

    We present a spatial system called Specialized Egocentrically Coordinated Spaces embedded in an embodied cognitive architecture (ACT-R Embodied). We show how the spatial system works by modeling two different developmental findings: gaze-following and Level 1 perspective taking. The gaze-following model is based on an experiment by Corkum and Moore (1998), whereas the Level 1 visual perspective-taking model is based on an experiment by Moll and Tomasello (2006). The models run on an embodied robotic system. PMID:25164505

  15. Spatial Data - the Fundament for the National Spatial Data Infrastructure of the Republic of Macedonia

    Microsoft Academic Search

    Dimo TODOROVSKI

    SUMMARY Countries that have sustainable development and application of the principles of 'good governance' in perspective, sooner or later start developing strategies for development and implementation of National spatial data infrastructure (NSDI). In the Republic of Macedonia (RM) the 'need' for development of NSDI should be accepted and observed from perspective of: how to accomplish the 'big picture' so called

  16. Improving Spatially Distributed Regional Recharge Estimation

    NASA Astrophysics Data System (ADS)

    Zomlot, Zainab; Batelaan, Okke

    2010-05-01

    Spatial and temporal variability of groundwater recharge are key factors that need to be quantified to determine the sustainability of groundwater resources. In response to the need for better estimates of groundwater recharge the WetSpass spatially distributed water balance model was developed and applied for Flanders. This model aims to simulate long-term average recharge depending on land cover, soil texture, topography and hydrometeorological parameters. The model simulates recharge iteratively connected to a groundwater model, such that the recharge estimate is also influenced by the groundwater depth and vice versa. The application of the model shows that the resulting recharge has a spatial complex pattern, depending to a large extend on the soil texture and land cover. Moreover, shallow groundwater levels in valleys cause negative recharge conditions as a result of evapotranspiration by abundant phreatophytic vegetation. For more dynamic recharge processes the WetSpa spatially distributed rainfall-runoff model can be applied. The aim of this contribution is to present WetSpass-WetSa recharge methodology and to evaluate the simulated spatially distributed recharge for Flanders on basis of baseflow time series of 67 river gauging stations distributed over Flanders.

  17. The Spatial Semantic Hierarchy

    Microsoft Academic Search

    Benjamin Kuipers

    2000-01-01

    The Spatial Semantic Hierarchy is a model of knowledge of large-scale space consisting of multiple interacting representations, both qualitative and quantitative. The SSH is inspired by the properties of the human cognitive map, and is intended to serve both as a model of the human cognitive map and as a method for robot exploration and map-building. The multiple levels of

  18. The Gridfit algorithm: an efficient and effective approach to visualizing large amounts of spatial data

    Microsoft Academic Search

    Daniel A. Keim; Annemarie Herrmann

    1998-01-01

    In a large number of applications, data is collected and referenced by their spatial locations. Visualizing large amounts of spatially referenced data on a limited-size screen display often results in poor visualizations due to the high degree of overplotting of neighboring datapoints. We introduce a new approach to visualizing large amounts of spatially referenced data. The basic idea is to

  19. The Gridfit algorithm: an efficient and effective approach to visualizing large amounts of spatial data

    Microsoft Academic Search

    Daniel A. Keim; Annemarie Herrmann

    1998-01-01

    In a large number of applications, data is collected and referenced by their spatial locations. Visualizing large amounts of spatially referenceddata on a limited-size screen display often results in poor visualizations due to the high degree of overplotting of neighboring datapoints. In this paper, we introduce a new approach to visualizing large amounts of spatially referenceddata. The basic idea is

  20. Fusion of fuzzy spatial relations Nadeem SALAMAT, El-hadi ZAHZAH

    E-print Network

    Boyer, Edmond

    Fusion of fuzzy spatial relations Nadeem SALAMAT, El-hadi ZAHZAH Université de La Rochelle, ezahzah}@univ-lr.fr Abstract. Spatial relations are essential for understanding the image configuration spatial relations are computed separately as they have separate application domains. Intro- duction

  1. Statistical Analysis of Spatial Crime Data

    Microsoft Academic Search

    Wim Bernasco; Henk Elffers

    \\u000a While the geography of crime has been a focal concern in criminology from the very start of the discipline, the development\\u000a and use of statistical methods specifically designed for spatially referenced data has evolved more recently. This chapter\\u000a gives an overview of the application of such methods in research on crime and criminal justice, and provides references to\\u000a the general

  2. Hierarchical Spatial Modeling of Additive and Dominance Genetic Variance for Large Spatial Trial Datasets

    PubMed Central

    Finley, Andrew O.; Banerjee, Sudipto; Waldmann, Patrik; Ericsson, Tore

    2009-01-01

    Summary This article expands upon recent interest in Bayesian hierarchical models in quantitative genetics by developing spatial process models for inference on additive and dominance genetic variance within the context of large spatially referenced trial datasets. Direct application of such models to large spatial datasets are, however, computationally infeasible because of cubic-order matrix algorithms involved in estimation. The situation is even worse in Markov chain Monte Carlo (MCMC) contexts where such computations are performed for several iterations. Here, we discuss approaches that help obviate these hurdles without sacrificing the richness in modeling. For genetic effects, we demonstrate how an initial spectral decomposition of the relationship matrices negate the expensive matrix inversions required in previously proposed MCMC methods. For spatial effects, we outline two approaches for circumventing the prohibitively expensive matrix decompositions: the first leverages analytical results from Ornstein–Uhlenbeck processes that yield computationally efficient tridiagonal structures, whereas the second derives a modified predictive process model from the original model by projecting its realizations to a lower-dimensional subspace, thereby reducing the computational burden. We illustrate the proposed methods using a synthetic dataset with additive, dominance, genetic effects and anisotropic spatial residuals, and a large dataset from a Scots pine (Pinus sylvestris L.) progeny study conducted in northern Sweden. Our approaches enable us to provide a comprehensive analysis of this large trial, which amply demonstrates that, in addition to violating basic assumptions of the linear model, ignoring spatial effects can result in downwardly biased measures of heritability. PMID:18759829

  3. GENERATING SOPHISTICATED SPATIAL SURROGATES USING THE MIMS SPATIAL ALLOCATOR

    EPA Science Inventory

    The Multimedia Integrated Modeling System (MIMS) Spatial Allocator is open-source software for generating spatial surrogates for emissions modeling, changing the map projection of Shapefiles, and performing other types of spatial allocation that does not require the use of a comm...

  4. Spatial Attention and the Apprehension of Spatial Relations

    Microsoft Academic Search

    Gordon D. Logan

    1994-01-01

    Seven experiments examined the role of spatial attention in apprehending spatial relations above, below, left, and right. In Experiment 1, visual search was difficult when targets differed from distractors only in the spatial relation between their elements. Reaction time increased linearly with display size with a slope greater than 60 ms\\/item. In Experiment 2, search was easy (the slope was

  5. The agent-based spatial information semantic grid

    NASA Astrophysics Data System (ADS)

    Cui, Wei; Zhu, YaQiong; Zhou, Yong; Li, Deren

    2006-10-01

    Analyzing the characteristic of multi-Agent and geographic Ontology, The concept of the Agent-based Spatial Information Semantic Grid (ASISG) is defined and the architecture of the ASISG is advanced. ASISG is composed with Multi-Agents and geographic Ontology. The Multi-Agent Systems are composed with User Agents, General Ontology Agent, Geo-Agents, Broker Agents, Resource Agents, Spatial Data Analysis Agents, Spatial Data Access Agents, Task Execution Agent and Monitor Agent. The architecture of ASISG have three layers, they are the fabric layer, the grid management layer and the application layer. The fabric layer what is composed with Data Access Agent, Resource Agent and Geo-Agent encapsulates the data of spatial information system so that exhibits a conceptual interface for the Grid management layer. The Grid management layer, which is composed with General Ontology Agent, Task Execution Agent and Monitor Agent and Data Analysis Agent, used a hybrid method to manage all resources that were registered in a General Ontology Agent that is described by a General Ontology System. The hybrid method is assembled by resource dissemination and resource discovery. The resource dissemination push resource from Local Ontology Agent to General Ontology Agent and the resource discovery pull resource from the General Ontology Agent to Local Ontology Agents. The Local Ontology Agent is derived from special domain and describes the semantic information of local GIS. The nature of the Local Ontology Agents can be filtrated to construct a virtual organization what could provides a global scheme. The virtual organization lightens the burdens of guests because they need not search information site by site manually. The application layer what is composed with User Agent, Geo-Agent and Task Execution Agent can apply a corresponding interface to a domain user. The functions that ASISG should provide are: 1) It integrates different spatial information systems on the semantic The Grid management layer establishes a virtual environment that integrates seamlessly all GIS notes. 2) When the resource management system searches data on different spatial information systems, it transfers the meaning of different Local Ontology Agents rather than access data directly. So the ability of search and query can be said to be on the semantic level. 3) The data access procedure is transparent to guests, that is, they could access the information from remote site as current disk because the General Ontology Agent could automatically link data by the Data Agents that link the Ontology concept to GIS data. 4) The capability of processing massive spatial data. Storing, accessing and managing massive spatial data from TB to PB; efficiently analyzing and processing spatial data to produce model, information and knowledge; and providing 3D and multimedia visualization services. 5) The capability of high performance computing and processing on spatial information. Solving spatial problems with high precision, high quality, and on a large scale; and process spatial information in real time or on time, with high-speed and high efficiency. 6) The capability of sharing spatial resources. The distributed heterogeneous spatial information resources are Shared and realizing integrated and inter-operated on semantic level, so as to make best use of spatial information resources,such as computing resources, storage devices, spatial data (integrating from GIS, RS and GPS), spatial applications and services, GIS platforms, 7) The capability of integrating legacy GIS system. A ASISG can not only be used to construct new advanced spatial application systems, but also integrate legacy GIS system, so as to keep extensibility and inheritance and guarantee investment of users. 8) The capability of collaboration. Large-scale spatial information applications and services always involve different departments in different geographic places, so remote and uniform services are needed. 9) The capability of supporting integration of heterogeneous systems. Large-scale spatial information

  6. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, V.

    1992-12-15

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

  7. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, Victor (Berkeley, CA)

    1992-01-01

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

  8. Vibrotactile spatial summation

    Microsoft Academic Search

    James C. Craig

    1968-01-01

    By means of a two-interval, forced-choice technique, absolute thresholds were obtained at several sites on the skin for short\\u000a bursts of mechanical vibration. The difference between the energy required for a single vibrator, in dB, to reach threshold\\u000a and the energy required for two vibrators presented successively to reach threshold was taken as the measure of probability\\u000a summation. Spatial summation

  9. Spatial Data Analysis

    NASA Astrophysics Data System (ADS)

    Haining, Robert

    2003-06-01

    Are there geographic clusters of disease cases, or hotspots of crime? Can the geography of air quality be matched to where people hospitalized for respiratory complaints actually live? Spatial data is data about the world where the attribute of interest and its location on the earth's surface are recorded. This comprehensive overview of the subject shows how the above questions can be tackled. It is written for students and researchers in geography, economics, social science, the environmental sciences and statistics.

  10. A time-domain inversion technique for the tempo-spatial distribution of slip on a finite fault plane with applications to recent large earthquakes in the Tibetan Plateau

    Microsoft Academic Search

    Y. T. Chen; L. S. Xu

    2000-01-01

    A time-domain inversion technique is proposed to invert for the tempo-spatial distribution of slip on an earthquake fault plane. This technique is based on the idea that a finite fault plane can be divided into several subfaults, each of which can be treated as a point source, and that the source time function (STF) of the finite fault is the

  11. ISPRS Workshop on Service and Application of Spatial Data Infrastructure, XXXVI (4/W6), Oct.14-16, Hangzhou, China CONSTRUCT 3D CITY MODEL BY MULTI-SENSOR DATA

    E-print Network

    Salvaggio, Carl

    the other hand, laser scanner (LIDAR) has high potential of automating 3D modelling because it directly measure 3D coordinates of objects. It is a advantageous to integrate laser scanner data and digital camera with laser scanner data to making 3D spatial information with higher resolution in a efficient method

  12. Spatial Premise Integration in Hindi

    ERIC Educational Resources Information Center

    Mishra, Ramesh Kumar

    2007-01-01

    Spatial reasoning or locating objects in a spatial space has long been an important area of research in cognitive science because analyzing space categorically and finding objects is a fundamental act of mental perception and cognition. Premise integration in tasks of spatial reasoning has recently received considerable research attention. This is…

  13. Shared Readings in Spatial Hypermedia

    Microsoft Academic Search

    Luis Francisco-Revilla; Frank Shipman

    Spatial hypermedia research is revising and integrating ideas previously explored in navigational hypermedia, such as adaptation, distribution, integration of new media, etc. A result of one such investigation is the support personal readings of distributed spatial hypertexts via transclusion links. WARP provides the required platform for a first exploration of the issues associated with reading distributed spatial hypertexts. However there

  14. 3, 21752208, 2006 Rainfall spatial

    E-print Network

    Paris-Sud XI, Université de

    HESSD 3, 2175­2208, 2006 Rainfall spatial variation and catchment response J. M. Schuurmans and M and Earth System Sciences Effect of spatial distribution of daily rainfall on interior catchment response.schuurmans@geo.uu.nl) 2175 #12;HESSD 3, 2175­2208, 2006 Rainfall spatial variation and catchment response J. M. Schuurmans

  15. Modeling structural change in spatial system dynamics: A Daisyworld example

    PubMed Central

    Neuwirth, C.; Peck, A.; Simonovi?, S.P.

    2015-01-01

    System dynamics (SD) is an effective approach for helping reveal the temporal behavior of complex systems. Although there have been recent developments in expanding SD to include systems’ spatial dependencies, most applications have been restricted to the simulation of diffusion processes; this is especially true for models on structural change (e.g. LULC modeling). To address this shortcoming, a Python program is proposed to tightly couple SD software to a Geographic Information System (GIS). The approach provides the required capacities for handling bidirectional and synchronized interactions of operations between SD and GIS. In order to illustrate the concept and the techniques proposed for simulating structural changes, a fictitious environment called Daisyworld has been recreated in a spatial system dynamics (SSD) environment. The comparison of spatial and non-spatial simulations emphasizes the importance of considering spatio-temporal feedbacks. Finally, practical applications of structural change models in agriculture and disaster management are proposed.

  16. Chemistry with spatial control using particles and streams†

    PubMed Central

    Kalinin, Yevgeniy V.; Murali, Adithya

    2012-01-01

    Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis. PMID:23145348

  17. APPLICATION APPLICATION

    E-print Network

    Jain, Raj

    in the network has three layers: physical layer, datalink layer (DLC) and application layer. Nodes in the network these entities communicate with one another, and will develop a DLC layer entity that performs error correction communicates through Protocol Data Units (PDU). The application layer PDU is called A_PDU, the DLC PDU

  18. APPLICATION APPLICATION

    E-print Network

    Jain, Raj

    that each node in the network has three layers: physical layer, datalink layer (DLC) and application layer will learn how these entities communicate with one another, and will develop a simple DLC layer entity (PDU). The application layer PDU is called A_PDU, the DLC PDU is called D_PDU, and the physical layer

  19. A General Model for Online Analytical Processing of Complex Data

    Microsoft Academic Search

    Jian Pei

    2003-01-01

    It has been well recognized that online analytical process- ing (OLAP) can provide important insights into huge archives of data. While the conventional OLAP model is capable of analyzing relational business data, it often cannot fit many kinds of complex data in emerging applications, such as bio-medical data, time series and semi-structured data. In this paper, we propose GOLAP, a

  20. Business Intelligence for Home Care Source Data and ETL Process

    E-print Network

    Kaiserslautern, Universität

    Business Intelligence for Home Care Source Data and ETL Process OLAP Cube and BI Application Future Work and Conclusion Business Intelligence in the Home Care Sector Peter Poulsen Lars Schunk Lasse Care Sector 1 / 32 #12;Business Intelligence for Home Care Source Data and ETL Process OLAP Cube and BI

  1. Abstract--Data mining aims at extraction of previously unidentified information from large databases. It can be

    E-print Network

    Fong, Chi Chiu "Simon"

    1 Abstract-- Data mining aims at extraction of previously unidentified information from large the last few years. Several works in the past emphasized the integration of OLAP and data mining. More recently, data mining techniques along with OLAP have been applied in decision support applications

  2. Audioworld: A Spatial Audio Tool for Acoustic and Cognitive Learning

    Microsoft Academic Search

    André Melzer; Martin Christof Kindsmüller; Michael Herczeg

    2010-01-01

    \\u000a The present paper introduces Audioworld, a novel game-like application for goal-oriented computer-supported learning (CSL). In Audioworld, participants localize sound emitting objects depending on their spatial position. Audioworld serves as a flexible low cost test bed for a broad range of human cognitive functions. This comprises the systematic training\\u000a of spatial navigation and localization skills, but also of verbal skills and

  3. EgoViz - A Mobile Based Spatial Interaction System

    Microsoft Academic Search

    Keith Gardiner; Junjun Yin; James D. Carswell

    2009-01-01

    This paper describes research carried out in the area of mobile spatial interaction and the development of a mobile (i.e. on-device) version of a simulated web-based 2D directional query processor. The TellMe application integrates location (from GPS, GSM, WiFi) and orientation (from digital compass\\/tilt sensors) sensing technologies into an enhanced spatial query processing module capable of exploiting a mobile device's

  4. On the Fast Construction of Spatial Hierarchies for Ray Tracing

    Microsoft Academic Search

    Vlastimil Havran; Robert Herzog; Hans-Peter Seidel

    2006-01-01

    In this paper we address the problem of fast construction of spatial hierarchies for ray tracing with applications in animated environments including non-rigid animations. We discuss the properties of currently used techniques with O(N log N) construction time for kd-trees and bounding volume hierarchies. Further, we propose a hybrid data structure blending a spatial kd-tree with bounding volume primitives. We

  5. USE OF THE SPATIAL KD-TREE IN COMPUTATIONAL PHYSICSAPPLICATIONS

    SciTech Connect

    Khamayseh, Ahmed K [ORNL; Hansen, Glen [Idaho National Laboratory (INL)

    2007-01-01

    The need to perform spatial queries and searches is commonly encountered within the field of computational physics. The development of applications ranging from scientific visualization to finite element analysis requires efficient methods of locating domain objects relative to general locations in space. Much of the time, it is possible to form and maintain spatial relationships between objects either explicitly or by using relative motion constraints as the application evolves in time. Occasionally, either due to unpredictable relative motion or the lack of state information, an application must perform a general search (or ordering) of geometric objects without any explicit spatial relationship information as a basis. If previous state information involving domain geometric objects is not available, it is typically an involved and time consuming process to create object adjacency information or to order the objects in space. Further, as the number of objects and the spatial dimension of the problem domain is increased, the time required to search increases greatly. This paper proposes an implementation of a spatial k-d tree (skD-tree) for use by various applications when a general domain search is required. The skD-tree proposed in this paper is a spatial access method where successive tree levels are split along different dimensions. Objects are indexed by their centroid, and the minimum bounding box of objects in a node are stored in the tree node. The paper focuses on a discussion of efficient and practical algorithms for multidimensional spatial data structures for fast spatial query processing. These functions include the construction of a skD-tree of geometric objects, intersection query, containment query, and nearest neighbor query operations.

  6. Spatial Modes of a Squeezed Vacuum Field

    NASA Astrophysics Data System (ADS)

    Zhang, Mi; Lanning, R. Nicholas; Xiao, Zhihao; Dowling, Jonathan P.; Novikova, Irina; Mikhailov, Eugeniy E.

    2015-03-01

    We prepared a quantum noise suppressed squeezed vacuum field by propagating a beam with a wavelength of 795nm through a hot Rb cell. Observation of the quadrature noise showed that we achieved a noise suppression of -2.0 dB below the quantum noise limit. When a spatial mask was applied to the beam after its interaction with atoms, we observed that the detected quantum noise suppression strongly depended on the shape of the mask. An exploration of the spatial distribution of noise in the squeezed field illustrated that the squeezed field was in a different spatial mode from the pump field used as a local oscillator. Our research showed that the squeezed field consisted of several spatial modes with various squeezing parameters. If a pure squeezed mode could be extracted, it would enhance the signal to noise ratio, which would impact precision metrology and quantum memory applications. This project is supported by AFOSR Grant FA9550-13-1-0098.

  7. Demonstration of polarization-insensitive spatial light modulation using a single polarization-sensitive spatial light modulator

    PubMed Central

    Liu, Jun; Wang, Jian

    2015-01-01

    We present a simple configuration incorporating a single polarization-sensitive phase-only liquid crystal spatial light modulator (LC-SLM) to facilitate polarization-insensitive spatial light modulation. The polarization-insensitive configuration is formed by a polarization beam splitter (PBS), a polarization-sensitive phase-only LC-SLM, a half-wave plate (HWP), and a mirror in a loop structure. We experimentally demonstrate polarization-insensitive spatial light modulations for incident linearly polarized beams with different polarization states and polarization-multiplexed beams. Polarization-insensitive spatial light modulations generating orbital angular momentum (OAM) beams are demonstrated in the experiment. The designed polarization-insensitive configuration may find promising applications in spatial light modulations accommodating diverse incident polarizations. PMID:26146032

  8. The spatial fluctuation theorem

    E-print Network

    Carlos Pérez-Espigares; Frank Redig; Cristian Giardinà

    2015-02-11

    For systems of interacting particles and for interacting diffusions in $d$ dimensions, driven out-of-equilibrium by an external field, a fluctuation relation for the generating function of the current is derived as a consequence of {\\em spatial symmetries}. Those symmetries are in turn associated to transformations on the physical space that leave invariant the path space measure of the system without driving. This shows that in dimension $d\\ge2$ new fluctuation relations arise beyond the Gallavotti-Cohen fluctuation theorem related to the time-reversal symmetry.

  9. Anatomical Global Spatial Normalization

    PubMed Central

    Cykowski, Matthew D.; McKay, David Reese; Kochunov, Peter V.; Fox, Peter T.; Rogers, William; Toga, Arthur W.; Zilles, Karl; Amunts, Katrin; Mazziotta, John

    2010-01-01

    Anatomical global spatial normalization (aGSN) is presented as a method to scale high-resolution brain images to control for variability in brain size without altering the mean size of other brain structures. Two types of mean preserving scaling methods were investigated, “shape preserving” and “shape standardizing”. aGSN was tested by examining 56 brain structures from an adult brain atlas of 40 individuals (LPBA40) before and after normalization, with detailed analyses of cerebral hemispheres, all gyri collectively, cerebellum, brainstem, and left and right caudate, putamen, and hippocampus. Mean sizes of brain structures as measured by volume, distance, and area were preserved and variance reduced for both types of scale factors. An interesting finding was that scale factors derived from each of the ten brain structures were also mean preserving. However, variance was best reduced using whole brain hemispheres as the reference structure, and this reduction was related to its high average correlation with other brain structures. The fractional reduction in variance of structure volumes was directly related to ?2, the square of the reference-to-structure correlation coefficient. The average reduction in variance in volumes by aGSN with whole brain hemispheres as the reference structure was approximately 32%. An analytical method was provided to directly convert between conventional and aGSN scale factors to support adaptation of aGSN to popular spatial normalization software packages. PMID:20582489

  10. Spatial uncertainty analysis: Propagation of interpolation errors in spatially distributed models

    USGS Publications Warehouse

    Phillips, D.L.; Marks, D.G.

    1996-01-01

    In simulation modelling, it is desirable to quantify model uncertainties and provide not only point estimates for output variables but confidence intervals as well. Spatially distributed physical and ecological process models are becoming widely used, with runs being made over a grid of points that represent the landscape. This requires input values at each grid point, which often have to be interpolated from irregularly scattered measurement sites, e.g., weather stations. Interpolation introduces spatially varying errors which propagate through the model We extended established uncertainty analysis methods to a spatial domain for quantifying spatial patterns of input variable interpolation errors and how they propagate through a model to affect the uncertainty of the model output. We applied this to a model of potential evapotranspiration (PET) as a demonstration. We modelled PET for three time periods in 1990 as a function of temperature, humidity, and wind on a 10-km grid across the U.S. portion of the Columbia River Basin. Temperature, humidity, and wind speed were interpolated using kriging from 700- 1000 supporting data points. Kriging standard deviations (SD) were used to quantify the spatially varying interpolation uncertainties. For each of 5693 grid points, 100 Monte Carlo simulations were done, using the kriged values of temperature, humidity, and wind, plus random error terms determined by the kriging SDs and the correlations of interpolation errors among the three variables. For the spring season example, kriging SDs averaged 2.6??C for temperature, 8.7% for relative humidity, and 0.38 m s-1 for wind. The resultant PET estimates had coefficients of variation (CVs) ranging from 14% to 27% for the 10-km grid cells. Maps of PET means and CVs showed the spatial patterns of PET with a measure of its uncertainty due to interpolation of the input variables. This methodology should be applicable to a variety of spatially distributed models using interpolated inputs.

  11. A performance evaluation framework for association mining in spatial data

    PubMed Central

    Wang, Qiang

    2010-01-01

    The evaluation of the process of mining associations is an important and challenging problem in database systems and especially those that store critical data and are used for making critical decisions. Within the context of spatial databases we present an evaluation framework in which we use probability distributions to model spatial regions, and Bayesian networks to model the joint probability distribution and the structural relationships among spatial and non-spatial predicates. We demonstrate the applicability of the proposed framework by evaluating representatives from two well-known approaches that are used for learning associations, i.e., dependency analysis (using statistical tests of independence) and Bayesian methods. By controlling the parameters of the framework we provide extensive comparative results of the performance of the two approaches. We obtain measures of recovery of known associations as a function of the number of samples used, the strength, number and type of associations in the model, the number of spatial predicates associated with a particular non-spatial predicate, the prior probabilities of spatial predicates, the conditional probabilities of the non-spatial predicates, the image registration error, and the parameters that control the sensitivity of the methods. In addition to performance we investigate the processing efficiency of the two approaches. PMID:21170170

  12. Lateral inhibition between spatially adjacent spatial-frequency channels?

    Microsoft Academic Search

    Dov Sagi; Shaul Hochstein

    1985-01-01

    A new lateral inhibitory phenomenon is suggested between spatially neighboring channels that detect similar spatial frequencies.\\u000a This mechanism tends to enhance the apparent contrast of gratings at their boundaries, and Mach-band-type effects are demonstrated\\u000a at the edge of a suprathreshold half-field grating. We studied the dependence of this effect on the grating parameters of\\u000a spatial frequency and contrast. The grating

  13. Diffusion-based spatial priors for imaging

    PubMed Central

    Harrison, L.M.; Penny, W.; Ashburner, J.; Trujillo-Barreto, N.; Friston, K.J.

    2007-01-01

    We describe a Bayesian scheme to analyze images, which uses spatial priors encoded by a diffusion kernel, based on a weighted graph Laplacian. This provides a general framework to formulate a spatial model, whose parameters can be optimized. The application we have in mind is a spatiotemporal model for imaging data. We illustrate the method on a random effects analysis of fMRI contrast images from multiple subjects; this simplifies exposition of the model and enables a clear description of its salient features. Typically, imaging data are smoothed using a fixed Gaussian kernel as a pre-processing step before applying a mass-univariate statistical model (e.g., a general linear model) to provide images of parameter estimates. An alternative is to include smoothness in a multivariate statistical model (Penny, W.D., Trujillo-Barreto, N.J., Friston, K.J., 2005. Bayesian fMRI time series analysis with spatial priors. Neuroimage 24, 350–362). The advantage of the latter is that each parameter field is smoothed automatically, according to a measure of uncertainty, given the data. In this work, we investigate the use of diffusion kernels to encode spatial correlations among parameter estimates. Nonlinear diffusion has a long history in image processing; in particular, flows that depend on local image geometry (Romeny, B.M.T., 1994. Geometry-driven Diffusion in Computer Vision. Kluwer Academic Publishers) can be used as adaptive filters. This can furnish a non-stationary smoothing process that preserves features, which would otherwise be lost with a fixed Gaussian kernel. We describe a Bayesian framework that incorporates non-stationary, adaptive smoothing into a generative model to extract spatial features in parameter estimates. Critically, this means adaptive smoothing becomes an integral part of estimation and inference. We illustrate the method using synthetic and real fMRI data. PMID:17869542

  14. Fractals and Spatial Methods for Mining Remote Sensing Imagery

    NASA Technical Reports Server (NTRS)

    Lam, Nina; Emerson, Charles; Quattrochi, Dale

    2003-01-01

    The rapid increase in digital remote sensing and GIS data raises a critical problem -- how can such an enormous amount of data be handled and analyzed so that useful information can be derived quickly? Efficient handling and analysis of large spatial data sets is central to environmental research, particularly in global change studies that employ time series. Advances in large-scale environmental monitoring and modeling require not only high-quality data, but also reliable tools to analyze the various types of data. A major difficulty facing geographers and environmental scientists in environmental assessment and monitoring is that spatial analytical tools are not easily accessible. Although many spatial techniques have been described recently in the literature, they are typically presented in an analytical form and are difficult to transform to a numerical algorithm. Moreover, these spatial techniques are not necessarily designed for remote sensing and GIS applications, and research must be conducted to examine their applicability and effectiveness in different types of environmental applications. This poses a chicken-and-egg problem: on one hand we need more research to examine the usability of the newer techniques and tools, yet on the other hand, this type of research is difficult to conduct if the tools to be explored are not accessible. Another problem that is fundamental to environmental research are issues related to spatial scale. The scale issue is especially acute in the context of global change studies because of the need to integrate remote-sensing and other spatial data that are collected at different scales and resolutions. Extrapolation of results across broad spatial scales remains the most difficult problem in global environmental research. There is a need for basic characterization of the effects of scale on image data, and the techniques used to measure these effects must be developed and implemented to allow for a multiple scale assessment of the data before any useful process-oriented modeling involving scale-dependent data can be conducted. Through the support of research grants from NASA, we have developed a software module called ICAMS (Image Characterization And Modeling System) to address the need to develop innovative spatial techniques and make them available to the broader scientific communities. ICAMS provides new spatial techniques, such as fractal analysis, geostatistical functions, and multiscale analysis that are not easily available in commercial GIS/image processing software. By bundling newer spatial methods in a user-friendly software module, researchers can begin to test and experiment with the new spatial analysis methods and they can gauge scale effects using a variety of remote sensing imagery. In the following, we describe briefly the development of ICAMS and present application examples.

  15. Wave optics simulation approach for partial spatially coherent beams.

    PubMed

    Xiao, Xifeng; Voelz, David

    2006-08-01

    A numerical wave optics approach for simulating a partial spatially coherent beam is presented. The approach involves the application of a sequence of random phase screens to an initial beam field and the summation of the intensity results after propagation. The relationship between the screen parameters and the spatial coherence function for the beam is developed and the approach is verified by comparing results with analytic formulations for a Gaussian Schell-model beam. The approach can be used for modeling applications such as free space optical laser links that utilize partially coherent beams. PMID:19529068

  16. Spatial pinning control.

    PubMed

    Frasca, Mattia; Buscarino, Arturo; Rizzo, Alessandro; Fortuna, Luigi

    2012-05-18

    In this Letter, we introduce the concept of spatial pinning control for a network of mobile chaotic agents. In a planar space, N agents move as random walkers and interact according to a time-varying r-disk proximity graph. A control input is applied only to those agents which enter a given area, called control region. The control is effective in driving all the agents to a reference evolution and has better performance than pinning control on a fixed set of agents. We derive analytical conditions on the relative size of the control region and the agent density for the global convergence of the system to the reference evolution and study the system under different regimes inherited by the velocity. PMID:23003148

  17. Spatial Query for Planetary Data

    NASA Technical Reports Server (NTRS)

    Shams, Khawaja S.; Crockett, Thomas M.; Powell, Mark W.; Joswig, Joseph C.; Fox, Jason M.

    2011-01-01

    Science investigators need to quickly and effectively assess past observations of specific locations on a planetary surface. This innovation involves a location-based search technology that was adapted and applied to planetary science data to support a spatial query capability for mission operations software. High-performance location-based searching requires the use of spatial data structures for database organization. Spatial data structures are designed to organize datasets based on their coordinates in a way that is optimized for location-based retrieval. The particular spatial data structure that was adapted for planetary data search is the R+ tree.

  18. ALGORITHM DEVELOPMENT FOR SPATIAL OPERATORS.

    USGS Publications Warehouse

    Claire, Robert W.

    1984-01-01

    An approach is given that develops spatial operators about the basic geometric elements common to spatial data structures. In this fashion, a single set of spatial operators may be accessed by any system that reduces its operands to such basic generic representations. Algorithms based on this premise have been formulated to perform operations such as separation, overlap, and intersection. Moreover, this generic approach is well suited for algorithms that exploit concurrent properties of spatial operators. The results may provide a framework for a geometry engine to support fundamental manipulations within a geographic information system.

  19. Spatio-Temporal Data Warehousing: a Survey Leticia Gmez

    E-print Network

    Libre de Bruxelles, Université

    or overlayed to obtain an integrated spatial view. On the other hand, OLAP (On Line Analytical Processing of the Coverage data model is also supported by the Reference Model proposed by the Open Geospatial Consortium2

  20. Synergy Between Ground Measurements and High Spatial Resolution Imagery to Validate Medium Spatial Resolution Land Surface Product

    NASA Astrophysics Data System (ADS)

    Garrigues, S.; Morisette, J.; Baret, F.; Privette, J.

    2005-12-01

    Currently, several biophysical variables such as the Leaf Area Index (LAI), the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) and the surface albedo are derived from remote sensing observations acquired with medium spatial resolution sensors (250m to 7km). Because of their high temporal frequency and their important spatial coverage, these products are very useful to describe the mass and energy fluxes between the earth surface and the atmosphere. Since these variables are required for an important range of investigations and applications, it is important to assess their accuracy. Validation activity consists in evaluating by independent means the quality of the land surface products estimated from coarse resolution sensors. Validation methods consist in generating a ground truth map of these products at high spatial resolution. These maps are produced by using ground measurements of the biophysical variable and radiometric data from a high spatial resolution sensor (10m-30m). The relationship between a biophysical variable and radiometric imagery, called the transfer function, allows extending the local ground measurements to the entire high spatial resolution image. The resulting biophysical variable map is aggregated to be compared with the medium spatial resolution satellite biophysical products. Several geometrical issues influence the validation results: - the registration accuracy of the local ground measurements relative to the high spatial resolution image - the difference of spatial support between the ground measurement support and the high spatial resolution pixel - the registration accuracy between the high and medium resolution images - the point spread function (PSF) associated to the medium spatial resolution image This work proposes a methodology to account for these sources of uncertainties within the validation process. First, these problems are investigated at the field measurement scale. The registration accuracy between ground measurement located by GPS and high spatial resolution pixel is modeled by a Gaussian random variable. For each possible relative position, the ground measurement is related to the radiometric data for the surrounding area weighted by the ground measurement spatial support area. A Monte Carlo simulation scheme accounting for the positional accuracy provides the probability distribution function of the parameters defining the transfer function. Second, registration error is investigated when aggregated high spatial resolution image is compared with coarse resolution image. The registration error is minimized by getting the best geometrical match between the two images using correlation techniques. Finally, the importance of the PSF associated to the medium spatial resolution biophysical products is evaluated using data from MODIS and VEGETATION sensors. This investigation is applied to several validation sites expressing a range of spatial heterogeneity.

  1. Spatial learning Hampton Court maze (London) Spatial learning: Small (1899)

    E-print Network

    Cooper, Brenton G.

    1899-01-01

    Spatial learning Hampton Court maze (London) #12;Goal Start Spatial learning: Small (1899) #12;Small (1899): recreation Small, 1899, Amer J Psychol, 12, 133-164. #12;Maze learning T-maze Radial-arm maze Morris water maze Barnes maze #12;Tolman's (1948) evidence for cognitive mapping (broad sense

  2. One Spatial Map or Many? Spatial Coding of Connected Environments

    ERIC Educational Resources Information Center

    Han, Xue; Becker, Suzanna

    2014-01-01

    We investigated how humans encode large-scale spatial environments using a virtual taxi game. We hypothesized that if 2 connected neighborhoods are explored jointly, people will form a single integrated spatial representation of the town. However, if the neighborhoods are first learned separately and later observed to be connected, people will…

  3. Constructing Spatial Meaning: Spatial Affordances in Museum Design

    ERIC Educational Resources Information Center

    Wineman, Jean D.; Peponis, John

    2010-01-01

    Informal education in museums is structured through movement in space. This article summarizes a range of research that examines the role of spatial layout in shaping the ways in which visitors explore, engage, and understand museums and museum exhibitions. It is demonstrated that behavior patterns are systematically linked to spatial

  4. DAMAGE REDUCTION BY CULTURE BASED METHOD SUPPORTED BY SPATIAL TEMPORAL GIS - COLLABORATIVE RESEARCH WITH DUZCE MUNICIPALITY TURKEY

    Microsoft Academic Search

    Shigeru KAKUMOTO; Michinori HATAYAMA; Yoshio KAJITANI

    Spatial temporal GIS named DiMSIS (Disaster Management Spatial Information System) have been developed mainly focused on applying local government applications after the great HANSHIN earthquake of 1995 in Japan. This spatial temporal GIS which has been enhanced to have multi language support would be common core system to support Risk Adaptive Regional Management Information System (RARMIS) concept proposed after the

  5. Quadratic spatial soliton interactions

    NASA Astrophysics Data System (ADS)

    Jankovic, Ladislav

    Quadratic spatial soliton interactions were investigated in this Dissertation. The first part deals with characterizing the principal features of multi-soliton generation and soliton self-reflection. The second deals with two beam processes leading to soliton interactions and collisions. These subjects were investigated both theoretically and experimentally. The experiments were performed by using potassium niobate (KNBO 3) and periodically poled potassium titanyl phosphate (KTP) crystals. These particular crystals were desirable for these experiments because of their large nonlinear coefficients and, more importantly, because the experiments could be performed under non-critical-phase-matching (NCPM) conditions. The single soliton generation measurements, performed on KNBO3 by launching the fundamental component only, showed a broad angular acceptance bandwidth which was important for the soliton collisions performed later. Furthermore, at high input intensities multi-soliton generation was observed for the first time. The influence on the multi-soliton patterns generated of the input intensity and beam symmetry was investigated. The combined experimental and theoretical efforts indicated that spatial and temporal noise on the input laser beam induced multi-soliton patterns. Another research direction pursued was intensity dependent soliton routing by using of a specially engineered quadratically nonlinear interface within a periodically poled KTP sample. This was the first time demonstration of the self-reflection phenomenon in a system with a quadratic nonlinearity. The feature investigated is believed to have a great potential for soliton routing and manipulation by engineered structures. A detailed investigation was conducted on two soliton interaction and collision processes. Birth of an additional soliton resulting from a two soliton collision was observed and characterized for the special case of a non-planar geometry. A small amount of spiraling, up to 30 degrees rotation, was measured in the experiments performed. The parameters relevant for characterizing soliton collision processes were also studied in detail. Measurements were performed for various collision angles (from 0.2 to 4 degrees), phase mismatch, relative phase between the solitons and the distance to the collision point within the sample (which affects soliton formation). Both the individual and combined effects of these collision variables were investigated. Based on the research conducted, several all-optical switching scenarios were proposed.

  6. Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

    NASA Astrophysics Data System (ADS)

    Song, Huihui

    Remote sensing provides good measurements for monitoring and further analyzing the climate change, dynamics of ecosystem, and human activities in global or regional scales. Over the past two decades, the number of launched satellite sensors has been increasing with the development of aerospace technologies and the growing requirements on remote sensing data in a vast amount of application fields. However, a key technological challenge confronting these sensors is that they tradeoff between spatial resolution and other properties, including temporal resolution, spectral resolution, swath width, etc., due to the limitations of hardware technology and budget constraints. To increase the spatial resolution of data with other good properties, one possible cost-effective solution is to explore data integration methods that can fuse multi-resolution data from multiple sensors, thereby enhancing the application capabilities of available remote sensing data. In this thesis, we propose to fuse the spatial resolution with temporal resolution and spectral resolution, respectively, based on sparse representation theory. Taking the study case of Landsat ETM+ (with spatial resolution of 30m and temporal resolution of 16 days) and MODIS (with spatial resolution of 250m ~ 1km and daily temporal resolution) reflectance, we propose two spatial-temporal fusion methods to combine the fine spatial information of Landsat image and the daily temporal resolution of MODIS image. Motivated by that the images from these two sensors are comparable on corresponding bands, we propose to link their spatial information on available Landsat- MODIS image pair (captured on prior date) and then predict the Landsat image from the MODIS counterpart on prediction date. To well-learn the spatial details from the prior images, we use a redundant dictionary to extract the basic representation atoms for both Landsat and MODIS images based on sparse representation. Under the scenario of two prior Landsat-MODIS image pairs, we build the corresponding relationship between the difference images of MODIS and ETM+ by training a low- and high-resolution dictionary pair from the given prior image pairs. In the second scenario, i.e., only one Landsat- MODIS image pair being available, we directly correlate MODIS and ETM+ data through an image degradation model. Then, the fusion stage is achieved by super-resolving the MODIS image combining the high-pass modulation in a two-layer fusion framework. Remarkably, the proposed spatial-temporal fusion methods form a unified framework for blending remote sensing images with phenology change or land-cover-type change. Based on the proposed spatial-temporal fusion models, we propose to monitor the land use/land cover changes in Shenzhen, China. As a fast-growing city, Shenzhen faces the problem of detecting the rapid changes for both rational city planning and sustainable development. However, the cloudy and rainy weather in region Shenzhen located makes the capturing circle of high-quality satellite images longer than their normal revisit periods. Spatial-temporal fusion methods are capable to tackle this problem by improving the spatial resolution of images with coarse spatial resolution but frequent temporal coverage, thereby making the detection of rapid changes possible. On two Landsat-MODIS datasets with annual and monthly changes, respectively, we apply the proposed spatial-temporal fusion methods to the task of multiple change detection. Afterward, we propose a novel spatial and spectral fusion method for satellite multispectral and hyperspectral (or high-spectral) images based on dictionary-pair learning and sparse non-negative matrix factorization. By combining the spectral information from hyperspectral image, which is characterized by low spatial resolution but high spectral resolution and abbreviated as LSHS, and the spatial information from multispectral image, which is featured by high spatial resolution but low spectral resolution and abbreviated as HSLS, this method aims to generate the fused data with both high spa

  7. Visualizations of Spatial Distribution Functions

    E-print Network

    Petta, Jason

    distribution - to study the SDF of water and hydronium around sulfonate group and side chain. SpatialVisualizations of Spatial Distribution Functions A.Z. Pangiotopoulos Kevin Daly Kareem Mehrabiani - operated in a hydrated state because adding water raises proton conductivity - causes this Microphase

  8. The Visual-Spatial Learner.

    ERIC Educational Resources Information Center

    Silverman, Linda Kreger

    1989-01-01

    Research with gifted children has identified certain clusters of traits which are directly related to a visual/spatial orientation in learning. This article presents common traits of visual/spatial learners, including introversion and behavior problems, and offers adaptive techniques that have been found effective in teaching "nonsequential"…

  9. MALARIA MODELS WITH SPATIAL EFFECTS

    E-print Network

    Ruan, Shigui

    CHAPTER 1 MALARIA MODELS WITH SPATIAL EFFECTS Daozhou Gao1 and Shigui Ruan2 1 Francis I. Proctor provide a brief review about some recent studies on mathematical modeling of malaria transmission and reaction-diffusion equations are used to investigate the spatial spread of malaria be- tween humans

  10. Spatial measures of software complexity

    Microsoft Academic Search

    C. R. Douce; P. J. Layzell; J. Buckley

    This paper introduces a set of simple software complexity metrics that has been in- spired by developments within cognitive psychology. Complexity measures are con- structed by analysing the distance between components of a program. The greater the distance between program fragments, the greater the resulting spatial complexity of a program. Suggestions are made as to how spatial complexity measures can

  11. Posttranscriptional Gene Regulation by Spatial

    E-print Network

    Bedwell, David M.

    Posttranscriptional Gene Regulation by Spatial Rearrangement of the 3 Untranslated Region Andrea B for Posttranscriptional Gene Regualtion by spatial Rearrangement of 3'UTR #12;A Competition between Stimulators Intron Enhances NMD PABC1 Antagonizes the interaction between eRF3 and hUpf1 in vitro #12;A Competition

  12. Spatial pattern and ecological analysis

    Microsoft Academic Search

    Pierre Legendre I; Marie-Josre Fortin

    1989-01-01

    The spatial heterogeneity of populations and communities plays a central role in many ecological theories, for instance the theories of succession, adaptation, maintenance of species diversity, community stability, competition, predator-prey interactions, parasitism, epidemics and other natural catastrophes, ergoclines, and so on. This paper will review how the spatial structure of biological populations and communities can be studied. We first demonstrate

  13. Wind Energy and Spatial Technology

    E-print Network

    Schweik, Charles M.

    2/3/2011 1 Wind Energy and Spatial Technology Lori Pelech Why Wind Energy? A clean, renewable 2,600 tons of carbon emissions annually ­ The economy · Approximately 85,000 wind energy workers to Construct a Wind Farm... Geo-Spatial Components of Wind Farm Development Process Selecting a Project Site

  14. Noise-induced spatial patterns

    Microsoft Academic Search

    Juan M. R. Parrondo; Christian van den Broeck; Javier Buceta; F. Javier de la Rubia

    1996-01-01

    By modifying the spatial coupling a la Swift-Hohenberg in the model introduced in Phys. Rev. Lett. 73 (1994) 3395, we obtain a system that displays noise-induced spatial patterns. We present a mean field theory of this phenomenon and verify some of its predictions by numerical simulations.

  15. SGPP: spatial Gaussian predictive process models for neuroimaging data.

    PubMed

    Hyun, Jung Won; Li, Yimei; Gilmore, John H; Lu, Zhaohua; Styner, Martin; Zhu, Hongtu

    2014-04-01

    The aim of this paper is to develop a spatial Gaussian predictive process (SGPP) framework for accurately predicting neuroimaging data by using a set of covariates of interest, such as age and diagnostic status, and an existing neuroimaging data set. To achieve a better prediction, we not only delineate spatial association between neuroimaging data and covariates, but also explicitly model spatial dependence in neuroimaging data. The SGPP model uses a functional principal component model to capture medium-to-long-range (or global) spatial dependence, while SGPP uses a multivariate simultaneous autoregressive model to capture short-range (or local) spatial dependence as well as cross-correlations of different imaging modalities. We propose a three-stage estimation procedure to simultaneously estimate varying regression coefficients across voxels and the global and local spatial dependence structures. Furthermore, we develop a predictive method to use the spatial correlations as well as the cross-correlations by employing a cokriging technique, which can be useful for the imputation of missing imaging data. Simulation studies and real data analysis are used to evaluate the prediction accuracy of SGPP and show that SGPP significantly outperforms several competing methods, such as voxel-wise linear model, in prediction. Although we focus on the morphometric variation of lateral ventricle surfaces in a clinical study of neurodevelopment, it is expected that SGPP is applicable to other imaging modalities and features. PMID:24269800

  16. Evaluation methods for association rules in spatial knowlegde base

    NASA Astrophysics Data System (ADS)

    Niu, X.; Ji, X.

    2014-04-01

    Association rule is an important model in data mining. It describes the relationship between predicates in transactions, makes the expression of knowledge hidden in data more specific and clear. While the developing and applying of remote sensing technology and automatic data collection tools in recent decades, tremendous amounts of spatial and non-spatial data have been collected and stored in large spatial database, so association rules mining from spatial database becomes a significant research area with extensive applications. How to find effective, reliable and interesting association rules from vast information for helping people analyze and make decision has become a significant issue. Evaluation methods measure spatial association rules with evaluation criteria. On the basis of analyzing the existing evaluation criteria, this paper improved the novelty evaluation method, built a spatial knowledge base, and proposed a new evaluation process based on the support-confidence evaluation system. Finally, the feasibility of the new evaluation process was validated by an experiment with real-world geographical spatial data.

  17. Femtosecond spatial pulse shaping at the focal plane.

    PubMed

    Martínez-Matos, Ó; Vaveliuk, P; Izquierdo, J G; Loriot, V

    2013-10-21

    Spatial shaping of ultrashort laser beams at the focal plane is theoretically analyzed. The description of the pulse is performed by its expansion in terms of Laguerre-Gaussian orthonormal modes. This procedure gives both a comprehensive interpretation of the propagation dynamics and the required signal to encode onto a spatial light modulator for spatial shaping, without using iterative algorithms. As an example, pulses with top-hat and annular spatial profiles are designed and their dynamics analyzed. The interference of top-hat pulses is also investigated finding potential applications in high precision pump-probe experiments (without using delay lines) and for the creation of subwavelength ablation patterns. In addition, a novel class of ultrashort pulses possessing non-stationary orbital angular momentum is also proposed. These exotic pulses provide additional degrees of freedom that open up new perspectives in fields such as laser-matter interaction and micro-machining. PMID:24150344

  18. Mechanisms for Human Spatial Competence

    NASA Astrophysics Data System (ADS)

    Gunzelmann, Glenn; Lyon, Don R.

    Research spanning decades has generated a long list of phenomena associated with human spatial information processing. Additionally, a number of theories have been proposed about the representation, organization and processing of spatial information by humans. This paper presents a broad account of human spatial competence, integrated with the ACT-R cognitive architecture. Using a cognitive architecture grounds the research in a validated theory of human cognition, enhancing the plausibility of the overall account. This work posits a close link of aspects of spatial information processing to vision and motor planning, and integrates theoretical perspectives that have been proposed over the history of research in this area. In addition, the account is supported by evidence from neuropsychological investigations of human spatial ability. The mechanisms provide a means of accounting for a broad range of phenomena described in the experimental literature.

  19. Hadoop-GIS: A High Performance Spatial Data Warehousing System over MapReduce.

    PubMed

    Aji, Ablimit; Wang, Fusheng; Vo, Hoang; Lee, Rubao; Liu, Qiaoling; Zhang, Xiaodong; Saltz, Joel

    2013-08-01

    Support of high performance queries on large volumes of spatial data becomes increasingly important in many application domains, including geospatial problems in numerous fields, location based services, and emerging scientific applications that are increasingly data- and compute-intensive. The emergence of massive scale spatial data is due to the proliferation of cost effective and ubiquitous positioning technologies, development of high resolution imaging technologies, and contribution from a large number of community users. There are two major challenges for managing and querying massive spatial data to support spatial queries: the explosion of spatial data, and the high computational complexity of spatial queries. In this paper, we present Hadoop-GIS - a scalable and high performance spatial data warehousing system for running large scale spatial queries on Hadoop. Hadoop-GIS supports multiple types of spatial queries on MapReduce through spatial partitioning, customizable spatial query engine RESQUE, implicit parallel spatial query execution on MapReduce, and effective methods for amending query results through handling boundary objects. Hadoop-GIS utilizes global partition indexing and customizable on demand local spatial indexing to achieve efficient query processing. Hadoop-GIS is integrated into Hive to support declarative spatial queries with an integrated architecture. Our experiments have demonstrated the high efficiency of Hadoop-GIS on query response and high scalability to run on commodity clusters. Our comparative experiments have showed that performance of Hadoop-GIS is on par with parallel SDBMS and outperforms SDBMS for compute-intensive queries. Hadoop-GIS is available as a set of library for processing spatial queries, and as an integrated software package in Hive. PMID:24187650

  20. A spatial operator algebra for manipulator modeling and control

    NASA Technical Reports Server (NTRS)

    Rodriguez, G.; Kreutz, K.; Milman, M.

    1988-01-01

    A powerful new spatial operator algebra for modeling, control, and trajectory design of manipulators is discussed along with its implementation in the Ada programming language. Applications of this algebra to robotics include an operator representation of the manipulator Jacobian matrix; the robot dynamical equations formulated in terms of the spatial algebra, showing the complete equivalence between the recursive Newton-Euler formulations to robot dynamics; the operator factorization and inversion of the manipulator mass matrix which immediately results in O(N) recursive forward dynamics algorithms; the joint accelerations of a manipulator due to a tip contact force; the recursive computation of the equivalent mass matrix as seen at the tip of a manipulator; and recursive forward dynamics of a closed chain system. Finally, additional applications and current research involving the use of the spatial operator algebra are discussed in general terms.

  1. Spatial Hyperschematia without Spatial Neglect after Insulo-Thalamic Disconnection

    PubMed Central

    Saj, Arnaud; Wilcke, Juliane C.; Gschwind, Markus; Emond, Héloïse; Assal, Frédéric

    2013-01-01

    Different spatial representations are not stored as a single multipurpose map in the brain. Right brain-damaged patients can show a distortion, a compression of peripersonal and extrapersonal space. Here we report the case of a patient with a right insulo-thalamic disconnection without spatial neglect. The patient, compared with 10 healthy control subjects, showed a constant and reliable increase of her peripersonal and extrapersonal egocentric space representations - that we named spatial hyperschematia - yet left her allocentric space representations intact. This striking dissociation shows that our interactions with the surrounding world are represented and processed modularly in the human brain, depending on their frame of reference. PMID:24302992

  2. Integrated Agricultural Pest Management Through Remote Sensing And Spatial Analyses

    Microsoft Academic Search

    Maggi Kelly; Qinghua Guo

    Modern agriculture is influenced by both the pressure for increased productivity and increased stresses caused by plant pests.\\u000a Geographical Information Systems and Global Positioning Systems are currently being used for variable rate application of\\u000a pesticides, herbicide and fertilizers in Precision Agriculture applications, but the comparatively lesser-used tools of Remote\\u000a Sensing and Spatial Analyses can be of additional value in integrated

  3. Spatial wave field characteristics in Arctic seas

    NASA Astrophysics Data System (ADS)

    Gemmrich, Johannes; Rogers, Erick; Lehner, Susanne; Pleskachevsky, Andrey; Thomson, Jim

    2015-04-01

    The reduction of the sea ice coverage during the boreal summer will lead to an increased importance of wind waves for the dynamic processes of the Arctic Seas. Larger ice free areas lead to longer fetch and thus longer and higher sea state. Wind waves will enhance upper-ocean mixing, may affect the breakup of ice sheets, and will likely lead to increased coastal erosion. Our long-term goal is a better understanding of the two-way interaction of waves and sea-ice, in order to improve wave models as well as ice models applicable to a changing Arctic wave- and ice climate. Wind, wave and ice information has been retrieved from space-borne SAR imagery (TerraSAR-X), collected during the period August-September 2014 in the Beaufort Sea. The SAR data were co-located with drifting wave-buoys and wave gliders. This information complements and validates model data (Wavewatch III) for the spatial and temporal evolution of sea state in the Arctic. We will present examples of wind and wave fields under different wind forcing and ice conditions, and discuss the advantages of each of the three observational/modelling approaches. These examples highlight the strong spatial heterogeneity of the wave field in arctic regions, and the need for high resolution spatial wave observations. Satellite-based wave field observations can bridge the gap between the single point buoy observation that provide high resolution time series of wave parameters, and the output of wave models which are of relatively coarse resolution and are inherently limited by the quality of the wind and ice input fields, but are unlimited in their spatial and temporal extent.

  4. Manakov spatial solitons

    NASA Astrophysics Data System (ADS)

    Kang, J. U.; Stegeman, G. I.; Aitchison, J. S.; Akhmediev, N.

    1996-12-01

    The Manakov soliton is a two-component soliton that was first considered by Manakov in the early 1970s.1 Based on the work of Zakharov and Shabat,2 Manakov found that the coupled nonlinear Schrodinger (CNSE) equations with special choice of the coefficients in front of nonlinear terms can be solved exactly. This system is integrable and solitons have therefore a number of special properties which might be useful in practice. In particular, for same total power, the soliton of a single nonlinear Schrodinger equation and the Manakov soliton behave similarly. There are certain conditions for the integrability of the CNSE. Namely, for the coupled set of equations with cubic nonlinearity, the ratio between the self-phase modulation (SPM) to the cross-phase modulation coefficients has to be equal to unity, and the SPM coefficients need to be equal for the two polarizations. Moreover, the energy exchange terms or four-wave mixing (FWM) terms must be zero. Physically, the Manakov soliton is a mutually trapped state of two orthogonally polarized beams where each component of the soliton experiences exactly the same index potential which is proportional to the total intensity of the beam. There are no crystal symmetries that a priori lead to a SPM/XPM ratio of unity. Thus, the Manakov soliton has not been observed experimentally prior to the work we reported.3 Based on our previous work, we found that in AlGaAs, for photon energies just below half the band gap, the conditions for integrability can be satisfied. This led to the first experimental observation of spatial Manakov solitons.

  5. Bearing-based selection in mobile spatial interaction

    Microsoft Academic Search

    Steven Strachan; Roderick Murray-smith

    2009-01-01

    We introduce a mobile spatial interactive application that uses a combination of a GPS, inertial sensing, gestural interaction, probabilistic models and Monte Carlo sampling, with vibration and audio feedback. This system allows the probing or querying of targets in a local area, based on a model of the local environment and specific context variables of interest, to enable a rich,

  6. Significant wave height prediction by using a spatial model

    Microsoft Academic Search

    Abdüsselam Altunkaynak

    2005-01-01

    Spatial assessment of variables in a considered region saves its significance for engineering applications. Branches in ocean engineering need the results of this assessment like radius of influence of stations that records the wave measurements and various meteorological variables values. Classical approaches like Kriging do not provide radius of influence for the concerned station. On the other hand, prediction of

  7. A Process Model of the Formation of Spatial Presence Experiences

    Microsoft Academic Search

    Werner Wirth; Tilo Hartmann; Saskia Böcking; Peter Vorderer; Christoph Klimmt; Holger Schramm; Timo Saari; Jari Laarni; Niklas Ravaja; Feliz Ribeiro Gouveia; Frank Biocca; Ana Sacau; Lutz Jäncke; Thomas Baumgartner; Petra Jäncke

    2007-01-01

    In order to bridge interdisciplinary differences in Presence research and to establish connections between Presence and “older” concepts of psychology and communication, a theoretical model of the formation of Spatial Presence is proposed. It is applicable to the exposure to different media and intended to unify the existing efforts to develop a theory of Presence. The model includes assumptions about

  8. On the probability and spatial distribution of ocean surface currents

    E-print Network

    Ashkenazy, Yossi "Yosef"

    On the probability and spatial distribution of ocean surface currents Yosef Ashkenazy Solar Energy into the probability distribution of ocean currents are important for various applications such as the chance the probability distribution of surface currents from the Gulf of Eilat/Aqaba measured by high-frequency radar

  9. Approximate methods in Bayesian point process spatial models

    Microsoft Academic Search

    Andrew B. Lawson

    2009-01-01

    A range of point process models which are commonly used in spatial epidemiology applications for the increased incidence of disease are compared. The models considered vary from approximate methods to an exact method. The approximate methods include the Poisson process model and methods that are based on discretization of the study window. The exact method includes a marked point process

  10. Spatial reasoning in a fuzzy region connection calculus

    Microsoft Academic Search

    Steven Schockaert; Martine De Cock; Etienne E. Kerre

    2009-01-01

    Although the region connection calculus (RCC) oers an appealing framework for modelling topological relations, its application in real-world scenarios is hampered when spatial phenomena are aected by vagueness. To cope with this, we present a generalization of the RCC based on fuzzy set theory, and discuss how reasoning tasks such as satisfiability and entailment checking can be cast into linear

  11. SPATIAL RESOLUTION AND QUANTIZATION NOISE TRADEOFFS FOR SCALABLE IMAGE COMPRESSION

    E-print Network

    Pappas, Thrasyvoulos N.

    SPATIAL RESOLUTION AND QUANTIZATION NOISE TRADEOFFS FOR SCALABLE IMAGE COMPRESSION Soo Hyun Bae to a distorted image at the same level of resolution assuming a fixed viewing distance. In video streaming as spatiotemporal resolution. For example, at low bitrate coding applications the compressed image may be too dis

  12. 1 INTRODUCTION Accurate knowledge of spatial and temporal varia-

    E-print Network

    Zreda, Marek

    prediction and flood forecasting (Entekhabi et al. 1996, Alemaw et al. 2006). Such data are essential moisture conditions in flood fore- casting models. The fundamental limitation is that spatial and temporal information is of critical importance to real-world applications such as agricul- ture, water resource

  13. A spatial user interface to the astronomical literature

    Microsoft Academic Search

    P. Poincot; S. Lesteven; F. Murtagh

    1998-01-01

    We recall the properties of the Kohonen self-organizing feature map (SOM or SOFM), and explain how such maps can be used for information retrieval. We present an application to a bibliographic database. Our neural net can contain more than one level when necessary, which allows users to modify its spatial configuration. It is available for interactive use on the World-Wide

  14. Simulating Spatial Reasoning Using ACT-R

    Microsoft Academic Search

    Jona Boeddinghaus; Marco Ragni; Bernhard Nebel

    We present an ACT-R model of spatial reasoning based on the SRM model (Spatial Reasoning by Models). This model maps spatial working memory to a two-dimensional array and uses a spatial focus to place objects in the array, manipulate the position of objects, and inspect the array to find spatial relations that are not given in the premises. Since the

  15. The Detection of Clusters with Spatial Heterogeneity

    ERIC Educational Resources Information Center

    Zhang, Zuoyi

    2011-01-01

    This thesis consists of two parts. In Chapter 2, we focus on the spatial scan statistics with overdispersion and Chapter 3 is devoted to the randomized permutation test for identifying local patterns of spatial association. The spatial scan statistic has been widely used in spatial disease surveillance and spatial cluster detection. To apply it, a…

  16. Using spatial principles to optimize distributed computing for enabling the physical science discoveries

    PubMed Central

    Yang, Chaowei; Wu, Huayi; Huang, Qunying; Li, Zhenlong; Li, Jing

    2011-01-01

    Contemporary physical science studies rely on the effective analyses of geographically dispersed spatial data and simulations of physical phenomena. Single computers and generic high-end computing are not sufficient to process the data for complex physical science analysis and simulations, which can be successfully supported only through distributed computing, best optimized through the application of spatial principles. Spatial computing, the computing aspect of a spatial cyberinfrastructure, refers to a computing paradigm that utilizes spatial principles to optimize distributed computers to catalyze advancements in the physical sciences. Spatial principles govern the interactions between scientific parameters across space and time by providing the spatial connections and constraints to drive the progression of the phenomena. Therefore, spatial computing studies could better position us to leverage spatial principles in simulating physical phenomena and, by extension, advance the physical sciences. Using geospatial science as an example, this paper illustrates through three research examples how spatial computing could (i) enable data intensive science with efficient data/services search, access, and utilization, (ii) facilitate physical science studies with enabling high-performance computing capabilities, and (iii) empower scientists with multidimensional visualization tools to understand observations and simulations. The research examples demonstrate that spatial computing is of critical importance to design computing methods to catalyze physical science studies with better data access, phenomena simulation, and analytical visualization. We envision that spatial computing will become a core technology that drives fundamental physical science advancements in the 21st century. PMID:21444779

  17. The emergence of spatial cyberinfrastructure

    PubMed Central

    Wright, Dawn J.; Wang, Shaowen

    2011-01-01

    Cyberinfrastructure integrates advanced computer, information, and communication technologies to empower computation-based and data-driven scientific practice and improve the synthesis and analysis of scientific data in a collaborative and shared fashion. As such, it now represents a paradigm shift in scientific research that has facilitated easy access to computational utilities and streamlined collaboration across distance and disciplines, thereby enabling scientific breakthroughs to be reached more quickly and efficiently. Spatial cyberinfrastructure seeks to resolve longstanding complex problems of handling and analyzing massive and heterogeneous spatial datasets as well as the necessity and benefits of sharing spatial data flexibly and securely. This article provides an overview and potential future directions of spatial cyberinfrastructure. The remaining four articles of the special feature are introduced and situated in the context of providing empirical examples of how spatial cyberinfrastructure is extending and enhancing scientific practice for improved synthesis and analysis of both physical and social science data. The primary focus of the articles is spatial analyses using distributed and high-performance computing, sensor networks, and other advanced information technology capabilities to transform massive spatial datasets into insights and knowledge. PMID:21467227

  18. Verbs, events and spatial representations.

    PubMed

    Chatterjee, A; Southwood, M H; Basilico, D

    1999-04-01

    Are concepts expressed in language also represented spatially? To pursue this question we investigated the structure of events. Events are defined as actions with spatial trajectories that can be perceived by our senses and described in language. Events are expressed linguistically in sentences containing verbs which determine the thematic roles of the arguments (e.g., who is doing what to whom, where). Because of previous observations we focused on whether events are represented spatially by location of thematic roles and direction of actions. Location and direction were dissociated by contrasting different kinds of verbs: 'push' vs 'pull' in which actions move toward or away from the agent. To control for spatial effects produced by the surface structure of a left to right written language, we kept the structure of sentences constant and sought for spatial biases produced by differences in the meaning of these sentences. From three experiments using drawing and sentence-picture matching reaction time tasks, we found that normal subjects located agents to the left of patients and represented actions with a left to right directionality. These results are not easily explained by features of the surface structure of language or properties of propositional representations. We suggest that events have spatial representations in addition to their propositional counterparts of verbs and thematic roles. The specific spatial properties observed may relate to functional properties of the left hemisphere. PMID:10215086

  19. SPATIAL STRUCTURE, SPATIAL INTERACTION, AND DISTANCE-DECAY PARAMETERS

    Microsoft Academic Search

    ALEXANDER STEWART FOTHERINGHAM

    1980-01-01

    One result of calibrating a spatial interaction model using interaction data specific to an origin i is to produce an estimate of the distance-decay parameter specific to that origin ((beta)(,i)). A correct interpretation of (beta)(,i) is important since it is frequently used as a descriptive statistic of the spatial system under investigation and as a parameter for predicting unknown interactions.^

  20. Rocketborne spatial radiometer -- SPIRIT II

    SciTech Connect

    Kemp, J.C.; Larsen, K.D. (Utah State Univ., Logan, UT (United States). Space Dynamics Lab.); Huppi, E.R. (Phillips Lab., Hanscom AFB, MA (United States))

    1994-01-01

    A 300-element spatial radiometer was recently flown as part of the second Spatial Spectral Rocketborne Interferometer Telescope experiment. This instrument, housed in a high-off-axis-rejection telescope cooled to liquid helium temperatures, measured the spatial structure within six long-wavelength infrared spectral bands of the earthlimb. The radiometer used hybrid multiplexed focal planes with blocked impurity band detectors. The use of this technology enabled several enhancements to system performance. New data collection and analysis tools contributed significantly to the development and enhancement of this radiometer. Postflight analysis shows that the radiometer performed well during its sounding rocket flight.

  1. The effect of spatial aggregation on performance when mapping a risk of disease

    PubMed Central

    2014-01-01

    Background Spatial data on cases are available either in point form (e.g. longitude/latitude), or aggregated by an administrative region (e.g. zip code or census tract). Statistical methods for spatial data may accommodate either form of data, however the spatial aggregation can affect their performance. Previous work has studied the effect of spatial aggregation on cluster detection methods. Here we consider geographic health data at different levels of spatial resolution, to study the effect of spatial aggregation on disease mapping performance in locating subregions of increased disease risk. Methods We implemented a non-parametric disease distance-based mapping (DBM) method to produce a smooth map from spatially aggregated childhood leukaemia data. We then simulated spatial data under controlled conditions to study the effect of spatial aggregation on its performance. We used an evaluation method based on ROC curves to compare performance of DBM across different geographic scales. Results Application of DBM to the leukaemia data illustrates the method as a useful visualization tool. Spatial aggregation produced expected degradation of disease mapping performance. Characteristics of this degradation, however, varied depending on the interaction between the geographic extent of the higher risk area and the level of aggregation. For example, higher risk areas dispersed across several units did not suffer as greatly from aggregation. The choice of centroids also had an impact on the resulting mapping. Conclusions DBM can be implemented for continuous and discrete spatial data, but the resulting mapping can lose accuracy in the second setting. Investigation of the simulations suggests a complex relationship between performance loss, geographic extent of spatial disturbances and centroid locations. Aggregation of spatial data destroys information and thus impedes efforts to monitor these data for spatial disturbances. The effect of spatial aggregation on cluster detection, disease mapping, and other useful methods in spatial epidemiology is complex and deserves further study. PMID:24625068

  2. A reliable spatially normalized template of the human spinal cord - Applications to automated white matter/gray matter segmentation and tensor-based morphometry (TBM) mapping of gray matter alterations occurring with age.

    PubMed

    Taso, Manuel; Le Troter, Arnaud; Sdika, Michaël; Cohen-Adad, Julien; Arnoux, Pierre-Jean; Guye, Maxime; Ranjeva, Jean-Philippe; Callot, Virginie

    2015-08-15

    Recently, a T2*-weighted template and probabilistic atlas of the white and gray matter (WM, GM) of the spinal cord (SC) have been reported. Such template can be used as tissue-priors for automated WM/GM segmentation but can also provide a common reference and normalized space for group studies. Here, a new template has been created (AMU40), and accuracy of automatic template-based WM/GM segmentation was quantified. The feasibility of tensor-based morphometry (TBM) for studying voxel-wise morphological differences of SC between young and elderly healthy volunteers was also investigated. Sixty-five healthy subjects were divided into young (n=40, age<40years old, mean age 28±5years old) and elderly (n=25, age>50years old, mean age 57±5years old) groups and scanned at 3T using an axial high-resolution T2*-weighted sequence. Inhomogeneity correction and affine intensity normalization of the SC and cerebrospinal fluid (CSF) signal intensities across slices were performed prior to both construction of the AMU40 template and WM/GM template-based segmentation. The segmentation was achieved using non-linear spatial normalization of T2*-w MR images to the AMU40 template. Validation of WM/GM segmentations was performed with a leave-one-out procedure by calculating DICE similarity coefficients between manual and automated WM/GM masks. SC morphological differences between young and elderly healthy volunteers were assessed using the same non-linear spatial normalization of the subjects' MRI to a common template, derivation of the Jacobian determinant maps from the warping fields, and a TBM analysis. Results demonstrated robust WM/GM automated segmentation, with mean DICE values greater than 0.8. Concerning the TBM analysis, an anterior GM atrophy was highlighted in elderly volunteers, demonstrating thereby, for the first time, the feasibility of studying local structural alterations in the SC using tensor-based morphometry. This holds great promise for studies of morphological impairment occurring in several central nervous system pathologies. PMID:26003856

  3. Modeling the spatial shape of nondiffracting beams: Experimental generation of Frozen Waves via holographic method

    NASA Astrophysics Data System (ADS)

    Vieira, Tárcio A.; Zamboni-Rached, Michel; Gesualdi, Marcos R. R.

    2014-03-01

    In this paper we experimentally implement the spatial shape modeling of nondiffracting optical beams via computer generated holograms reconstructed optically by spatial light modulators. The results reported here are an experimental confirmation of the so-called Frozen Wave method, developed a few years ago. Optical beams of this type have potential applications in optical tweezers, medicine, atom guiding, remote sensing, etc.

  4. Spatial Node Distribution of Manhattan Path Based Random Waypoint Mobility Models

    E-print Network

    Rossi, Gianluca

    Spatial Node Distribution of Manhattan Path Based Random Waypoint Mobility Models with Applications of Manhattan or (more realistically) Bezier paths. We provide analytical results for the spatial node stationary distribution for the two Manhattan based RWP mobility models and experimental evidence

  5. QUANTIFYING MICROSCOPIC MORPHOLOGY WITH FOURIER HOLOGRAPHIC SPATIALLY RESOLVED ANGULAR SCATTERING SPECTROSCOPY

    Microsoft Academic Search

    Sergey A. Alexandrov; Timothy R. Hillman; Thomas Gutzler; David D. Sampson

    2005-01-01

    Quantitative microscopy of large areas of samples is very important for many applications, especially in medicine and biology. In microscopy, the geometrical parameters of sample microstructure are measured directly with an accuracy that depends on the microscope's spatial resolution. The requirement for high spatial resolution often restricts the field of view to substantially less than the region of interest. As

  6. Functional convergence of tundra vegetation simplifies the interpretation of flux observations at larger spatial scales

    Microsoft Academic Search

    P. C. Stoy; M. Williams; J. G. Evans; C. R. Lloyd; A. Prieto-Blanco; M. Disney; G. R. Shaver

    2007-01-01

    A central challenge in terrestrial carbon cycle research is upscaling measurements of vegetation function to larger spatial and temporal scales. A solution is required to, for example, make chamber-based measurements relevant at larger spatial scales and to make eddy covariance measurements applicable to leaf or chamber- based studies. Here we demonstrate that a simple model for photosynthesis and ecosystem respiration

  7. NON-SPATIAL CALIBRATIONS OF A GENERAL UNIT MODEL FOR ECOSYSTEM SIMULATIONS. (R825792)

    EPA Science Inventory

    General Unit Models simulate system interactions aggregated within one spatial unit of resolution. For unit models to be applicable to spatial computer simulations, they must be formulated generally enough to simulate all habitat elements within the landscape. We present the d...

  8. NON-SPATIAL CALIBRATIONS OF A GENERAL UNIT MODEL FOR ECOSYSTEM SIMULATIONS. (R827169)

    EPA Science Inventory

    General Unit Models simulate system interactions aggregated within one spatial unit of resolution. For unit models to be applicable to spatial computer simulations, they must be formulated generally enough to simulate all habitat elements within the landscape. We present the d...

  9. Spatial frequency response of conventional and non-conventional SQUID gradiometers

    Microsoft Academic Search

    E. Andrade Lima; A. C. Bruno

    2003-01-01

    The gradiometer spatial frequency response is an important performance feature, mainly if one wants to tailor a gradiometer design to specific applications. Because many nonconventional planar gradiometers have been recently built, we extend a two-dimensional filtering model that predicts the spatial frequency response of ordinary planar gradiometers to incorporate those designs, such as directly coupled and flip-chip gradiometers. We also

  10. Image Segmentation Using Fuzzy Clustering with Spatial Constraints Based on Markov Random Field via Bayesian Theory

    Microsoft Academic Search

    Xiaohe Li; Taiyi Zhang; Zhan Qu

    2008-01-01

    Image segmentation is an essential processing step for many image analysis applications. In this paper, a novel image segmentation algorithm using fuzzy C-means clustering (FCM) with spatial constraints based on Markov random field (MRF) via Bayesian theory is proposed. Due to disregard of spatial constraint information, the FCM algorithm fails to segment images corrupted by noise. In order to improve

  11. Assessing the spatial dynamics of debris-flow activity on a forested cone using dendroecological methods

    E-print Network

    Butler, David R. - Department of Geography, Texas State University

    Assessing the spatial dynamics of debris-flow activity on a forested cone using dendroecological big events may eliminate entire forest stands and therefore render the application approaches ­ dendrogeomorphology and minimum age dating ­ so as to reconstruct the spatial dynamics of past

  12. Visualizing the non-visual: spatial analysis and interaction with information from text documents

    Microsoft Academic Search

    James A. Wise; James J. Thomas; Kelly Pennock; David Lantrip; Marc Pottier; Anne Schur; V. Crow

    1995-01-01

    The paper describes an approach to IV that involves spatializing text content for enhanced visual browsing and analysis. The application arena is large text document corpora such as digital libraries, regulations and procedures, archived reports, etc. The basic idea is that text content from these sources may be transformed to a spatial representation that preserves informational characteristics from the documents.

  13. A Three-Dimensional Spatially Filtered FDTD with Controllable Stability Beyond the Courant Limit

    E-print Network

    A Three-Dimensional Spatially Filtered FDTD with Controllable Stability Beyond the Courant Limit Abstract-- It has been recently shown that the stability limit of the Finite-Difference Time-Domain (FDTD of the spatially filtered FDTD to three-dimensional applications and further demonstrates a three-dimensional late

  14. A comparison of spatial feature extraction algorithms for land-use classification with SPOT HRV data

    Microsoft Academic Search

    P GONG; D MARCEAU; P HOWARTH

    1992-01-01

    A large number of spatial feature extraction methods were developed during the past 20 years. The effectiveness of each method has been assessed in different studies using different data. However, there have been few application-oriented studies made to evaluate the relative powers of these meth- ods in a particular environment. In this study, three spatial feature extraction methods have been

  15. Effect of gis learning on spatial ability 

    E-print Network

    Lee, Jong Won

    2006-08-16

    This research used a spatial skills test and cognitive-mapping test to examine the effect of GIS learning on the spatial ability and spatial problem solving of college students. A total of 80 participants, undergraduate students at Texas A...

  16. Spatial modulation: theory to practice 

    E-print Network

    Younis, Abdelhamid

    2014-06-30

    Spatial modulation (SM) is a transmission technique proposed for multiple–input multiple– output (MIMO) systems, where only one transmit antenna is active at a time, offering an increase in the spectral efficiency equal ...

  17. Spatial Processing using Oracle Table Functions

    Microsoft Academic Search

    Kothuri Venkata Ravi Kanth; Siva Ravada; Weisheng Xu

    2003-01-01

    Spatial joins and spatial index creation are two of the most expensive operations in Oracle Spatial. Since spatial indexing is implemented in extensible indexing framework where queries only return rows from a single table, spatial joins could not be effectively and efficiently implemented in Oracle8i and prior releases. On the other hand, spatial indexcreationinvolvesmuchcomputationorI\\/Othatcouldbe easily parallelized. In this paper, we

  18. OLAP Technology for Business Process Intelligence: Challenges and Solutions

    E-print Network

    Scholl, Marc H.

    of business process management systems by employing data warehousing and mining technologies. However errors. However, the prevailing business process management systems focus on the design support, from discovering the optimization poten- tial for instrument and device usage to verifying medical

  19. Sampling cube: a framework for statistical olap over sampling data

    Microsoft Academic Search

    Xiaolei Li; Jiawei Han; Zhijun Yin; Jae-gil Lee; Yizhou Sun

    2008-01-01

    Sampling is a popular method of data collection when it is impossible or too costly to reach the entire population. For example, television show ratings in the United States are gathered from a sample of roughly 5,000 households. To use the results effectively, the samples are further partitioned in a multidimensional space based on multiple attribute values. This naturally leads

  20. Interactive spatial analysis of lineaments

    NASA Astrophysics Data System (ADS)

    Chandrasiri Ekneligoda, Thushan; Henkel, Herbert

    2010-08-01

    An interactive software tool, here called Spatial Analysis of Lineaments (SAL), has been developed for calculating the spatial properties azimuth, length, spacing, and unidirectional frequency of lineaments which are defined by their start and end coordinates. In a series of steps the user is guided by displays of relevant statistical distributions, which can be user designed. Statistical outliers can be excluded and the total sample of lineaments can be subdivided into azimuth sets and, if required, into spatial clusters. Special attention is given to the removal of spatial outliers in an interactive way. Several rule-based decisions are made to determine the nearest lineament in the spacing calculation. As a default procedure, the program defines a window whose size depends on the mode value of the length distribution of the lineaments in the study area. The software can accept a large amount of lineaments and can analyze the spatial properties of each azimuth set avoiding the repetitive calling of the original database. A simple rule was developed to derive the unidirectional lineament frequency. The spatial properties are presented as histograms for each azimuth set together with the mode, mean, standard deviation, and number of involved lineaments.

  1. Optimization-based Tuning of Low-bandwidth Control in Spatially

    E-print Network

    diverse array control applications related to thermal processing, including Rapid Thermal Processing structure' control of lightweight space reflector shape. (A 1-D distributed reflector control problemOptimization-based Tuning of Low-bandwidth Control in Spatially Distributed Systems Dimitry

  2. Effect of Temporal and Spatial Rainfall Resolution on HSPF Predictive Performance and Parameter Estimation

    EPA Science Inventory

    Watershed scale rainfall-runoff models are used for environmental management and regulatory modeling applications, but their effectiveness are limited by predictive uncertainties associated with model input data. This study evaluated the effect of temporal and spatial rainfall re...

  3. SPATIAL AND TEMPORAL VARIABILITY OF FECAL COLIFORMS AT AND NEAR A MANURED FIELD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluating the effect of field manure application on bacterial concentrations in creeks requires developing microbial transport models. Testing such models against bacterial monitoring data requires estimating the uncertainty in the data caused by spatial and temporal variability of bacterial concen...

  4. CMOS CURRENT/VOLTAGE MODE WINNER-TAKE-ALL CIRCUIT WITH SPATIAL FILTERING

    E-print Network

    CMOS CURRENT/VOLTAGE MODE WINNER-TAKE-ALL CIRCUIT WITH SPATIAL FILTERING Alexander Fish and Orly of the brightest object is sought. This includes star tracking, laser communication and many other applications

  5. COMPARISON OF GEOSTATISTICAL PROCEDURES FOR SPATIAL ANALYSIS OF PRECIPITATION IN MOUTAINOUS TERRAIN

    EPA Science Inventory

    Application of simulation models to assessment of global climate change effects often requires spatially distributed estimates of precipitation, both under current and future climate scenarios. imple interpolation methods fail to consider the effects of topography on precipitatio...

  6. Spatial Statistical Data Fusion (SSDF)

    NASA Technical Reports Server (NTRS)

    Braverman, Amy J.; Nguyen, Hai M.; Cressie, Noel

    2013-01-01

    As remote sensing for scientific purposes has transitioned from an experimental technology to an operational one, the selection of instruments has become more coordinated, so that the scientific community can exploit complementary measurements. However, tech nological and scientific heterogeneity across devices means that the statistical characteristics of the data they collect are different. The challenge addressed here is how to combine heterogeneous remote sensing data sets in a way that yields optimal statistical estimates of the underlying geophysical field, and provides rigorous uncertainty measures for those estimates. Different remote sensing data sets may have different spatial resolutions, different measurement error biases and variances, and other disparate characteristics. A state-of-the-art spatial statistical model was used to relate the true, but not directly observed, geophysical field to noisy, spatial aggregates observed by remote sensing instruments. The spatial covariances of the true field and the covariances of the true field with the observations were modeled. The observations are spatial averages of the true field values, over pixels, with different measurement noise superimposed. A kriging framework is used to infer optimal (minimum mean squared error and unbiased) estimates of the true field at point locations from pixel-level, noisy observations. A key feature of the spatial statistical model is the spatial mixed effects model that underlies it. The approach models the spatial covariance function of the underlying field using linear combinations of basis functions of fixed size. Approaches based on kriging require the inversion of very large spatial covariance matrices, and this is usually done by making simplifying assumptions about spatial covariance structure that simply do not hold for geophysical variables. In contrast, this method does not require these assumptions, and is also computationally much faster. This method is fundamentally different than other approaches to data fusion for remote sensing data because it is inferential rather than merely descriptive. All approaches combine data in a way that minimizes some specified loss function. Most of these are more or less ad hoc criteria based on what looks good to the eye, or some criteria that relate only to the data at hand.

  7. Filtering losslessly a single spatial mode of bright squeezed vacuum

    E-print Network

    A. M. Pérez; P. R. Sharapova; S. S. Straupe; F. M. Miatto; O. V. Tikhonova; G. Leuchs; M. V. Chekhova

    2015-02-23

    Bright squeezed vacuum state generated via high-gain parametric down conversion is a valuable resource for quantum information. Its highly multiphoton and multimode structure offers a huge increase in the information capacity provided that each mode can be addressed separately. Here we demonstrate lossless filtering of a single spatial Schmidt mode by projecting the spatial spectrum of bright squeezed vacuum on the eigenmode of a single-mode fiber. Moreover, we show that the first Schmidt mode can be captured by simply maximizing the fiber-coupled intensity. Importantly, the projection operation does not affect the radiation and leaves it usable for further applications.

  8. Spatially: resolved heterogeneous dynamics in a strong colloidal gel

    NASA Astrophysics Data System (ADS)

    Buzzaccaro, Stefano; Alaimo, Matteo David; Secchi, Eleonora; Piazza, Roberto

    2015-05-01

    We re-examine the classical problem of irreversible colloid aggregation, showing that the application of Digital Fourier Imaging (DFI), a class of optical correlation methods that combine the power of light scattering and imaging, allows one to pick out novel useful evidence concerning the restructuring processes taking place in a strong colloidal gel. In particular, the spatially-resolved displacement fields provided by DFI strongly suggest that the temporally-intermittent local rearrangements taking place in the course of gel ageing are characterized by very long-ranged spatial correlations.

  9. Particle dynamics in a spatially varying electric field

    SciTech Connect

    Rothwell, P.L. [Hanscom Air Force Base, Bedford, MA (United States)] [Hanscom Air Force Base, Bedford, MA (United States); Silevitch, M.B. [Northeastern Univ., Boston, MA (United States)] [Northeastern Univ., Boston, MA (United States); Block, L.P.; Faelthammar, C.G. [Royal Institute of Technology, Stockhoms (Sweden)] [Royal Institute of Technology, Stockhoms (Sweden)

    1995-08-01

    The particle dynamics of a plasma with finite first and second spatial derivatives in the electric field is solved. Macroscopic MHD phenomena are invalid in an explanation of single ion dynamics in a spatially varying one-dimensional electric field perpendicular to a magnetic field. We show there is no drift current in single ion motion in a magnetic field. We determine the ion drift velocity. Exact solutions are found in terms of Jacobian elliptic functions. We illustrate these results by application to the Harang discontinuity. 15 refs., 8 figs.

  10. Diffuse optical imaging using spatially and temporally modulated light

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Thomas D.; Cerussi, Albert E.; Cuccia, David J.; Tromberg, Bruce J.

    2012-07-01

    The authors describe the development of diffuse optical imaging (DOI) technologies, specifically the use of spatial and temporal modulation to control near infrared light propagation in thick tissues. We present theory and methods of DOI focusing on model-based techniques for quantitative, in vivo measurements of endogenous tissue absorption and scattering properties. We specifically emphasize the common conceptual framework of the scalar photon density wave for both temporal and spatial frequency-domain approaches. After presenting the history, theoretical foundation, and instrumentation related to these methods, we provide a brief review of clinical and preclinical applications from our research as well as our outlook on the future of DOI technology.

  11. Spatial memory: are lizards really deficient?

    PubMed Central

    LaDage, L. D.; Roth, T. C.; Cerjanic, A. M.; Sinervo, B.; Pravosudov, V. V.

    2012-01-01

    In many animals, behaviours such as territoriality, mate guarding, navigation and food acquisition rely heavily on spatial memory abilities; this has been demonstrated in diverse taxa, from invertebrates to mammals. However, spatial memory ability in squamate reptiles has been seen as possible, at best, or non-existent, at worst. Of the few previous studies testing for spatial memory in squamates, some have found no evidence of spatial memory while two studies have found evidence of spatial memory in snakes, but have been criticized based on methodological issues. We used the Barnes maze, a common paradigm to test spatial memory abilities in mammals, to test for spatial memory abilities in the side-blotched lizard (Uta stansburiana). We found the existence of spatial memory in this species using this spatial task. Thus, our study supports the existence of spatial memory in this squamate reptile species and seeks to parsimoniously align this species with the diverse taxa that demonstrate spatial memory ability. PMID:22933038

  12. Monitoring Method of Cow Anthrax Based on Gis and Spatial Statistical Analysis

    NASA Astrophysics Data System (ADS)

    Li, Lin; Yang, Yong; Wang, Hongbin; Dong, Jing; Zhao, Yujun; He, Jianbin; Fan, Honggang

    Geographic information system (GIS) is a computer application system, which possesses the ability of manipulating spatial information and has been used in many fields related with the spatial information management. Many methods and models have been established for analyzing animal diseases distribution models and temporal-spatial transmission models. Great benefits have been gained from the application of GIS in animal disease epidemiology. GIS is now a very important tool in animal disease epidemiological research. Spatial analysis function of GIS can be widened and strengthened by using spatial statistical analysis, allowing for the deeper exploration, analysis, manipulation and interpretation of spatial pattern and spatial correlation of the animal disease. In this paper, we analyzed the cow anthrax spatial distribution characteristics in the target district A (due to the secret of epidemic data we call it district A) based on the established GIS of the cow anthrax in this district in combination of spatial statistical analysis and GIS. The Cow anthrax is biogeochemical disease, and its geographical distribution is related closely to the environmental factors of habitats and has some spatial characteristics, and therefore the correct analysis of the spatial distribution of anthrax cow for monitoring and the prevention and control of anthrax has a very important role. However, the application of classic statistical methods in some areas is very difficult because of the pastoral nomadic context. The high mobility of livestock and the lack of enough suitable sampling for the some of the difficulties in monitoring currently make it nearly impossible to apply rigorous random sampling methods. It is thus necessary to develop an alternative sampling method, which could overcome the lack of sampling and meet the requirements for randomness. The GIS computer application software ArcGIS9.1 was used to overcome the lack of data of sampling sites.Using ArcGIS 9.1 and GEODA to analyze the cow anthrax spatial distribution of district A. we gained some conclusions about cow anthrax' density: (1) there is a spatial clustering model. (2) there is an intensely spatial autocorrelation. We established a prediction model to estimate the anthrax distribution based on the spatial characteristic of the density of cow anthrax. Comparing with the true distribution, the prediction model has a well coincidence and is feasible to the application. The method using a GIS tool facilitates can be implemented significantly in the cow anthrax monitoring and investigation, and the space statistics - related prediction model provides a fundamental use for other study on space-related animal diseases.

  13. SPATIAL MISMATCH OR RACIAL MISMATCH?*

    PubMed Central

    Hellerstein, Judith K.; Neumark, David; McInerney, Melissa

    2008-01-01

    We contrast the spatial mismatch hypothesis with what we term the racial mismatch hypothesis – that the problem is not a lack of jobs, per se, where blacks live, but a lack of jobs where blacks live into which blacks are hired. We first report new evidence on the spatial mismatch hypothesis, using data from Census Long-Form respondents. We construct direct measures of the presence of jobs in detailed geographic areas, and find that these job density measures are related to employment of black male residents in ways that would be predicted by the spatial mismatch hypothesis – in particular that spatial mismatch is primarily an issue for low-skilled black male workers. We then look at mismatch along not only spatial lines but racial lines as well, by estimating the effects of job density measures that are disaggregated by race. We find that it is primarily black job density that influences black male employment, whereas white job density has little if any influence on their employment. The evidence implies that space alone plays a relatively minor role in low black male employment rates. PMID:19727422

  14. High spatial resolution equilibrium reconstruction

    NASA Astrophysics Data System (ADS)

    Ren, Q.; Chu, M. S.; Lao, L. L.; Srinivasan, R.

    2011-09-01

    The extension of the EFIT equilibrium reconstruction code to fine spatial-grid resolutions is discussed. The residue in the force-balance relation of the Grad-Shafranov (G-S) equation and the convergence property of these fine spatial-grid EFIT equilibria are studied in detail. The results suggest that fine spatial-grid equilibria generally better satisfy the force-balance constraint described by the G-S equation. Finer spatial-grid equilibria have typically smaller average error in satisfying the force-balance equation than coarse-grid equilibria and those extrapolated from coarse-grid results. Analysis of the equilibrium iteration algorithm employed in EFIT reveals that the iteration process is related to the spatial feedback stabilization of the plasma with flux control at various specified locations. Thus, for a converged equilibrium, axisymmetric stability is generally expected with feedback. The iteration error decreases self-similarly in the final stage of the iteration process and is related to the least stable axisymmetric mode in the feedback-stabilized equilibrium.

  15. Spatial uncertainty and ecological models

    SciTech Connect

    Jager, Yetta [ORNL; King, Anthony Wayne [ORNL

    2004-07-01

    Applied ecological models that are used to understand and manage natural systems often rely on spatial data as input. Spatial uncertainty in these data can propagate into model predictions. Uncertainty analysis, sensitivity analysis, error analysis, error budget analysis, spatial decision analysis, and hypothesis testing using neutral models are all techniques designed to explore the relationship between variation in model inputs and variation in model predictions. Although similar methods can be used to answer them, these approaches address different questions. These approaches differ in (a) whether the focus is forward or backward (forward to evaluate the magnitude of variation in model predictions propagated or backward to rank input parameters by their influence); (b) whether the question involves model robustness to large variations in spatial pattern or to small deviations from a reference map; and (c) whether processes that generate input uncertainty (for example, cartographic error) are of interest. In this commentary, we propose a taxonomy of approaches, all of which clarify the relationship between spatial uncertainty and the predictions of ecological models. We describe existing techniques and indicate a few areas where research is needed.

  16. Spatial filtering with photonic crystals

    NASA Astrophysics Data System (ADS)

    Maigyte, Lina; Staliunas, Kestutis

    2015-03-01

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  17. Assessing temporal and spatial variability of hypoxia over the inner Louisiana-upper Texas shelf: Application of an unstructured-grid three-dimensional coupled hydrodynamic-water quality model

    NASA Astrophysics Data System (ADS)

    Justi?, Dubravko; Wang, Lixia

    2014-01-01

    Patterns of temporal and spatial variability in hypoxia (<2 mg O2 l-1) on the inner Louisiana-upper Texas (LaTex) shelf were examined using FVCOM LaTex, an unstructured grid, three-dimensional, hydrodynamic-water quality model. Dynamics of dissolved oxygen were modeled using an expanded and revised version of the Water Analysis Simulation Program (WASP) that was fully coupled to a Finite Volume Coastal Ocean Model (FVCOM). The coupled model was driven by surface wind forcing, tidal forcing, offshore remote forcing, heat fluxes, oxygen exchanges at the air-sea interface, solar radiation, and freshwater and nutrient (nitrogen and phosphorus) fluxes from the Mississippi and Atchafalaya Rivers. The model simulations were carried out over a 9-month period, from January 1 to October 4, 2002, and the model skill was assessed using multiple sets of observational data that included time series of dissolved oxygen concentrations from a station within the core of the Gulf hypoxic zone (C6), dissolved oxygen measurements collected during the mid-summer shelfwide cruise, and vertical dissolved oxygen profiles through the year. The model results indicate that hypoxia originates in bottom waters on the mid-continental shelf, where isolated pockets of hypoxic water develop during early spring and later join into a larger continuous hypoxic zone. The model accurately described the seasonal cycle of hypoxia at station C6, including the episodes of intermittent hypoxia during May and June, persistent hypoxia during July and August, and dissipation of hypoxia during September. The onset of hypoxia coincided with high stability of the water column (i.e., Richardson number values>1) and the initial transition from normoxia (i.e., 6 mg O2 l-1) to hypoxia lasted about three weeks. The model results point to a significant short-term variability in the extent of hypoxic bottom waters, indicating that the size of the mid-summer hypoxic zone cannot be adequately captured by a single shelfwide cruise. The dynamics of bottom-water hypoxia is clearly influenced by the bathymetric features of the LaTex shelf, namely the presence of three shallow shoals (<5 m) in the Atchafalaya Bay region and several deeper shoals (<10 m) in the northwestern section of the study area. Lastly, the model results support the view that dynamics of hypoxia on the LaTex shelf is strongly modulated by the frequency and intensity of cold fronts and tropical storms. High winds associated with these events disturb stratification, causing partial or complete breakdown of hypoxia. However, cold fronts and tropical storms also cause significant sediment resuspension that fuels respiration in the lower water column, and in this manner promote redevelopment of hypoxia.

  18. TEACHING SPATIAL STATISTICAL TECHNIQUES AND CONCEPTS

    Microsoft Academic Search

    Richard Castle

    The last decade has seen a rapid increase in the use of Geographical Information Systems (GIS) and the analysis of spatial data is an important component of this development. Spatial statistics is a relatively young subject and, although there are useful textbooks on spatial statistics theory, there is virtually no literature on how to teach spatial statistical concepts and techniques.

  19. Simple diagnostic tests for spatial dependence

    Microsoft Academic Search

    Luc Anselin; Anil K. Bera; Raymond Florax; Mann J. Yoon

    1996-01-01

    In this paper we propose simple diagnostic tests, based on ordinary least-squares (OLS) residuals, for spatial error autocorrelation in the presence of a spatially lagged dependent variable and for spatial lag dependence in the presence of spatial error autocorrelation, applying the modified Lagrange multiplier (LM) test developed by Bera and Yoon (Econometric Theory, 1993, 9, 649–658). Our new tests may

  20. Spatial synchrony in host–parasitoid populations

    Microsoft Academic Search

    Meng Gao; Wenlong Li; Zizhen Li; Huawei Dai; Hongtao Liu

    2007-01-01

    The ubiquity of spatial synchrony and its influences and causes have attracted the interest of ecologists. Spatially correlated environmental noises, dispersal, and trophic interactions have been considered as the causes of spatial synchrony. In this study, we developed a spatially implicit host–parasitoid model. Beside the above three mechanisms, correlation of environmental noise on different trophic levels was also included. Patterns