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1

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

PubMed Central

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 commercial off-the-shelf Geographic Information Systems (GIS) and Database Management Systems with spatial extensions. It has been widely recognized that such OLTP (On-Line Transaction Processing) systems were not designed to support complex, multi-temporal and multi-scale analysis as required above. On-Line Analytical Processing (OLAP) is central to the field known as BI (Business Intelligence), a key field for such decision-support systems. In the last few years, we have seen a few projects that combine OLAP and GIS to improve spatio-temporal analysis and geographic knowledge discovery. This has given rise to SOLAP (Spatial OLAP) and a new research area. This paper presents how SOLAP and climate-related health vulnerability data were investigated and combined to facilitate surveillance. Results Based on recent spatial decision-support technologies, this paper presents a spatio-temporal web-based application that goes beyond GIS applications with regard to speed, ease of use, and interactive analysis capabilities. It supports the multi-scale exploration and analysis of integrated socio-economic, health and environmental geospatial data over several periods. This project was meant to validate the potential of recent technologies to contribute to a better understanding of the interactions between public health and climate change, and to facilitate future decision-making by public health agencies and municipalities in Canada and elsewhere. The project also aimed at integrating an initial collection of geo-referenced multi-scale indicators that were identified by Canadian specialists and end-users as relevant for the surveillance of the public health impacts of climate change. This system was developed in a multidisciplinary context involving researchers, policy makers and practitioners, using BI and web-mapping concepts (more particularly SOLAP technologies), while exploring new solutions for frequent automatic updating of data and for providing contextual warnings for users (to minimize the risk of data misinterpretation). According to the project participants, the final system succeeds in facilitating surveillance activities in a way not achievable with today's GIS. Regarding the experiments on frequent automatic updating and contextual user warnings, the results obtained indicate that these are meaningful and achievable goals but they still require research and development for their successful implementation in the context of surveillance and multiple organizations. Conclusion Surveillance of climate-related health vulnerabilities may be more efficiently supported using a combination of BI and GIS concepts, and more specifically, SOLAP technologies (in that it facilitates and accelerates multi-scale spatial and temporal analysis to a point where a user can maintain an uninterrupted train of thought by focussing on "what" she/he wants (not on "how" to get it) and always obtain instant answers, including to the most complex queries that take minutes or hours with OLTP systems (e.g., aggregated, temporal, comparative)). The developed system respects Newell's cognitive band of 10 seconds when performing knowledge discovery (exploring data, looking for hypotheses, validating models). The developed system provides new operators for easily and rapidly exploring multidimensional data at different levels of granularity, for different regions and epochs, and for visualizing the results in synchronized maps, tables and charts. It is naturally adapted to deal with multiscale indicators such as those used in the surveillance community, as confirmed by thi

Bernier, Eveline; Gosselin, Pierre; Badard, Thierry; Bédard, Yvan

2009-01-01

2

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

Microsoft Academic Search

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

Eveline Bernier; Pierre Gosselin; Thierry Badard; Yvan Bédard

2009-01-01

3

Applying UML and XML for designing and interchanging information for data warehouses and OLAP applications  

Microsoft Academic Search

Multidimensional (MD) modeling is the basis for Data warehouses (DW), multidimensional databases (MDB) and On-Line Analytical Processing (OLAP) applications. In this paper, we present how the Unified Modeling Language (UML) can be successfully used to represent both structural and dynamic properties of these systems at the conceptual level. The structure of the system is specified by means of a UML

Juan Trujillo; Sergio Luján-mora; Il-yeol Song

2004-01-01

4

A Data Mining-Based OLAP Aggregation Running head: A DATA MINING-BASED OLAP AGGREGATION  

E-print Network

A Data Mining-Based OLAP Aggregation 1 Running head: A DATA MINING-BASED OLAP AGGREGATION A Data Mining-Based OLAPAggregation of Complex Data: Application on XML Documents Riadh Ben Messaoud, Omar://eric.univ-lyon2.fr/ halshs-00476497,version1-26Apr2010 Author manuscript, published in "N/P" #12;A Data Mining

Paris-Sud XI, Université de

5

Modelling Data Warehouses and OLAP Applications by Means of Dialogue Objects  

Microsoft Academic Search

. The idea of data warehouses is to provide condensed informationin order to support the management in the analysis of businessfacts such as sales, costs, prots, etc. along various dimensions such asgeography, organization, time, etc. The analysis should allow fast switchesbetween dierent selected multiple dimensions at dierent granularity.The task itself is usually called on-line analytical processing (OLAP).We show in this

Jana Lewerenz; Klaus-dieter Schewe; Bernhard Thalheim

1999-01-01

6

Applying GRID Technologies to XML Based OLAP Cube Construction  

E-print Network

On-Line Analytical Processing (OLAP) is a powerful method for analysing large data warehouse data. Typically, the data for an OLAP database is collected from a set of data repositories such as e.g. operational databases. This data set is often huge, and it may not be known in advance what data is required and when to perform the desired data analysis tasks. Sometimes it may happen that some parts of the data are only needed occasionally. Therefore, storing all data to the OLAP database and keeping this database constantly up-to-date is not only a highly demanding task but it also may be overkill in practice. This suggests that in some applications it would be more feasible to form the OLAP cubes only when they are actually needed. However, the OLAP cube construction can be a slow process. Thus, we present a system that applies Grid technologies to distribute the computation. As the data sources may well be heterogeneous, we propose an XML language for data collection. The user's definition for a OLAP new cube...

Niemi, Tapio Petteri; Nummenmaa, J; Thanisch, P

2002-01-01

7

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

Microsoft Academic Search

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

Nebojsa Stefanovic; Jiawei Han; Krzysztof Koperski

2000-01-01

8

CAMS: OLAPing Multidimensional Data Streams Efficiently  

NASA Astrophysics Data System (ADS)

In the context of data stream research, taming the multidimensionality of real-life data streams in order to efficiently support OLAP analysis/mining tasks is a critical challenge. Inspired by this fundamental motivation, in this paper we introduce CAMS (C ube-based A cquisition model for M ultidimensional S treams), a model for efficiently OLAPing multidimensional data streams. CAMS combines a set of data stream processing methodologies, namely (i) the OLAP dimension flattening process, which allows us to obtain dimensionality reduction of multidimensional data streams, and (ii) the OLAP stream aggregation scheme, which aggregates data stream readings according to an OLAP-hierarchy-based membership approach. We complete our analytical contribution by means of experimental assessment and analysis of both the efficiency and the scalability of OLAPing capabilities of CAMS on synthetic multidimensional data streams. Both analytical and experimental results clearly connote CAMS as an enabling component for next-generation Data Stream Management Systems.

Cuzzocrea, Alfredo

9

The Composite OLAP-Object Data Model  

SciTech Connect

In this paper, we define an OLAP-Object model that combines the main characteristics of OLAP and Object data models in order to achieve their functionalities in a common framework. We classify three different object classes: primitive, regular and composite. Then, we define a query language which uses the path concept in order to facilitate data navigation and data manipulation. The main feature of the proposed language is an anchor. It allows us to fix dynamically an object class (primitive, regular or composite) along the paths over the OLAP-Object data model for expressing queries. The queries can be formulated on objects, composite objects and combination of both. The power of the proposed query language is investigated through multiple query examples. The semantic of different clauses and syntax of the proposed language are investigated.

Pourabbas, Elaheh; Shoshani, Arie

2005-12-07

10

Updating OLAP Dimensions Carlos A. Hurtado  

E-print Network

Updating OLAP Dimensions Carlos A. Hurtado chl@db.toronto.edu University of Toronto Alberto O. These updates can take place either at the structural level e.g. addition of categories or modi cation of primitive dimension updates in a more e cient way. We also for- mally de ne two mappings normalized

Song, Il-Yeol

11

Range Queries in OLAP Data Cubes  

Microsoft Academic Search

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

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

1997-01-01

12

Constructing an OLAP cube from distributed XML data  

Microsoft Academic Search

On-Line Analytical Processing (OLAP) is a powerful method for analysing large data warehouse data. Typically, the data for an OLAP database is collected from a set of data repositories such as e.g. operational databases. This data set is often huge, and it may not be known in advance what data is required and when to perform the desired data analysis

Tapio Niemi; Marko Niinimäki; Jyrki Nummenmaa; Peter Thanisch

2002-01-01

13

Applying Grid Technologies to XML Based OLAP Cube Construction  

Microsoft Academic Search

On-Line Analytical Processing (OLAP) is a powerful method for analysing large data warehouse data. Typically, the data for an OLAP database is collected from a set of data repositories such as e.g. operational databases. This data set is often huge, and it may not be known in advance what data is required and when to perform the desired data analysis

Tapio Niemi; Marko Niinimäki; Jyrki Nummenmaa; Peter Thanisch

2003-01-01

14

Integrated Performance and Visualization Enhancements of OLAP Using Growing Self  

E-print Network

Integrated Performance and Visualization Enhancements of OLAP Using Growing Self Organizing Neural [3] proposed a functionality-enhancement technique using self-organizing neural networks@umac.mo Abstract--OLAP performance and its data visualization can be improved using different types of enhancement

Fong, Chi Chiu "Simon"

15

InfoNetOLAP: OLAP and Mining of Information Networks  

Microsoft Academic Search

\\u000a Databases and data warehouse systems have been evolving from handling normalized spreadsheets stored in relational databases\\u000a to managing and analyzing diverse application-oriented data with complex interconnecting structures. Responding to this emerging\\u000a trend, information networks have been growing rapidly and showing their critical importance in many applications, such as\\u000a the analysis of XML, social networks, Web, biological data, multimedia data, and

Chen Chen; Feida Zhu; Xifeng Yan; Jiawei Han; Philip Yu; Raghu Ramakrishnan

2010-01-01

16

An ETL Process for OLAP Using RDF\\/OWL Ontologies  

Microsoft Academic Search

In this paper, we present an advanced method for on-demand construction of OLAP cubes for ROLAP systems. The method contains\\u000a the steps from cube design to ETL but focuses on ETL. Actual data analysis can then be done using the tools and methods of\\u000a the OLAP software at hand. The method is based on RDF\\/OWL ontologies and design tools. The

Marko Niinimäki; Tapio Niemi

2009-01-01

17

Discovery-Driven Exploration of OLAP Data Cubes  

Microsoft Academic Search

.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

Sunita Sarawagi; Rakesh Agrawal; Nimrod Megiddo

1998-01-01

18

Database, Spatial Spatial databases are the foundation for computer-based applications involving spatially  

E-print Network

Database, Spatial Spatial databases are the foundation for computer-based applications involving, an orientation and a size). Spatial databases can be implemented using various technologies, the most common now to their intended purpose. There are two categories of spatial databases: transactional and analytical

19

Examining the Impact of Culture and Human Elements on OLAP Tools Usefulness  

ERIC Educational Resources Information Center

The purpose of the present study was to examine the impact of culture and human-related elements on the On-line Analytical Processing (OLAP) usability in generating decision-making information. The use of OLAP technology has evolved rapidly and gained momentum, mainly due to the ability of OLAP tools to examine and query large amounts of data sets…

Sharoupim, Magdy S.

2010-01-01

20

Bipolar fuzzy cognitive mapping and bipolar visualization for OLAP\\/OLAM  

Microsoft Academic Search

Bipolar fuzzy sets and bipolar fuzzy cognitive maps (FCMs) are introduced for online analytical processing (OLAP) and online analytical mining (OLAM). As cognitive models CMs hold great potential for visualization in OLAP and OLAM. Due to the lack of formal mathematical basis, however, CM-based OLAP and OLAM have not become popular. Compared with existing approaches, bipolar fuzzy sets and CMs

Wen-Ran Zhang

2002-01-01

21

Spatial Disease Surveillance: Methods and Applications  

E-print Network

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

Zhang, Tonglin

22

Miniaturized spatial filtering velocimeter for industrial applications  

Microsoft Academic Search

In this paper a miniaturized, direction-sensitive spatial filtering velocimeter is presented. A common charge coupled device (CCD) has been used as spatial filter for one-component velocity measurements. The characteristics of this sensor are investigated and first application results presented

K. Michel; K. Christofori; S. Bergeler; A. Richter; J. Kumpart; H. Krambeer; O. Fiedler

1998-01-01

23

Characterization of Hierarchies and Some Operators in OLAP environment  

E-print Network

-dimensionality) of these datasets, and in particular, of aggregate data [RaR83, ShW85, FRR86], as well as the concepts of dimension a multidimensional #12;2 data model for OLAP, and developed an algebra query language called Grouping Algebra

Song, Il-Yeol

24

Selective Materialization: An Efficient Method for Spatial Data Cube Construction  

Microsoft Academic Search

. 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

Jiawei Han; Nebojsa Stefanovic; Krzysztof Koperski

1998-01-01

25

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

E-print Network

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

Pei, Jian

26

cgmOLAP: Efficient Parallel Generation and Querying of Terabyte Size ROLAP Data Cubes  

E-print Network

Dalhousie University Halifax, Canada ychen@cs.dal.ca Frank Dehne Griffith University Brisbane, Australia wwwOLAP server, developed as part of the PANDA project [1] at Dalhousie, Concordia, Carleton and Griffith

Rau-Chaplin, Andrew

27

OLAP Hierarchies: A Conceptual Perspective1 E. Malinowski2, E. Zimnyi  

E-print Network

of organizations. The structure of a DW is usually represented using the star/snowflake schema, also called. 1. Example of a star and a snowflake schemas. On-Line Analytical Processing (OLAP) tools allow

Libre de Bruxelles, Université

28

Bayesian multivariate spatial models and their applications  

E-print Network

were found in Chen et al. (2002), Hobert and Casella (1996), and Chen et al. (2003). Ghosh et al. (1998) provided sufficient conditions to gain a proper joint posterior with a univariate CAR prior for spatial random effect. Since vague flat prior... for the propriety of the posterior and prior. Ghosh et al. (1998) present the theorem to ensure posterior propriety in hierar- chical Bayes generalized linear mixed models with spatial random effect. Sun et al. (2001) examined necessary and sufficient conditions...

Song, Joon Jin

2004-11-15

29

APPLICATION OF SPATIAL INFORMATION TECHNOLOGY TO PETROLEUM RESOURCE ASSESSMENT ANALYSIS.  

USGS Publications Warehouse

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.

Miller, Betty M.; Domaratz, Michael A.

1984-01-01

30

Radiographic applications of spatial frequency multiplexing  

NASA Technical Reports Server (NTRS)

The application of spacial frequency encoding techniques which allow different regions of the X-ray spectrum to be encoded on conventional radiographs was studied. Clinical considerations were reviewed, as were experimental studies involving the encoding and decoding of X-ray images at different energies and the subsequent processing of the data to produce images of specific materials in the body.

Macovski, A.

1981-01-01

31

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

E-print Network

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

Pei, Jian

32

Design and implementation of GGEarth spatial data service application system  

NASA Astrophysics Data System (ADS)

The digital earth concept has aroused strong repercussions and been arousing researches boom both at home and abroad once it is proposed. Many digital earth prototype systems have been researched and distributed in worldwide, and the Google Earth is more typical. The booming development of digital earth's research and its prototype's development bring about G/S mode timely, a novel spatial information distributing access, and organization software architecture mode. Based on native GML spatial database system and Google Earth, with G/S mode as its architecture, and combination with GML/KML compressive transport and transformation, this paper proposed and designed the software architecture of GGEarth spatial data service application system, the research content and key implementation technologies were given. This system provides functions of data presentation, query, update and spatial analysis, which uses native GML spatial database (and GML, KML documents) as the standard data center, and the client based on Google Earth COM API as the front-end. This system can be applied in fields of digital city, digital tourism and traditional Web GIS. The authors developed the GGEarth experimental system and ran it with the data of '5.12' Wenchuan earthquake timing and the model data of digital Jiuzhaigou virtual tourism. Some running screenshots are also given.

Chen, Jianhua; Miao, Fang; Wang, Weihong; Wang, Huajun

2009-06-01

33

Spatial effects in real networks: measures, null models, and applications.  

PubMed

Spatially embedded networks are shaped by a combination of purely topological (space-independent) and space-dependent formation rules. While it is quite easy to artificially generate networks where the relative importance of these two factors can be varied arbitrarily, it is much more difficult to disentangle these two architectural effects in real networks. Here we propose a solution to this problem, by introducing global and local measures of spatial effects that, through a comparison with adequate null models, effectively filter out the spurious contribution of nonspatial constraints. Our filtering allows us to consistently compare different embedded networks or different historical snapshots of the same network. As a challenging application we analyze the World Trade Web, whose topology is known to depend on geographic distances but is also strongly determined by nonspatial constraints (degree sequence or gross domestic product). Remarkably, we are able to detect weak but significant spatial effects both locally and globally in the network, showing that our method succeeds in retrieving spatial information even when nonspatial factors dominate. We finally relate our results to the economic literature on gravity models and trade globalization. PMID:23368007

Ruzzenenti, Franco; Picciolo, Francesco; Basosi, Riccardo; Garlaschelli, Diego

2012-12-01

34

Spatial effects in real networks: Measures, null models, and applications  

NASA Astrophysics Data System (ADS)

Spatially embedded networks are shaped by a combination of purely topological (space-independent) and space-dependent formation rules. While it is quite easy to artificially generate networks where the relative importance of these two factors can be varied arbitrarily, it is much more difficult to disentangle these two architectural effects in real networks. Here we propose a solution to this problem, by introducing global and local measures of spatial effects that, through a comparison with adequate null models, effectively filter out the spurious contribution of nonspatial constraints. Our filtering allows us to consistently compare different embedded networks or different historical snapshots of the same network. As a challenging application we analyze the World Trade Web, whose topology is known to depend on geographic distances but is also strongly determined by nonspatial constraints (degree sequence or gross domestic product). Remarkably, we are able to detect weak but significant spatial effects both locally and globally in the network, showing that our method succeeds in retrieving spatial information even when nonspatial factors dominate. We finally relate our results to the economic literature on gravity models and trade globalization.

Ruzzenenti, Franco; Picciolo, Francesco; Basosi, Riccardo; Garlaschelli, Diego

2012-12-01

35

Random vectors and spatial analysis by geostatistics for geotechnical applications  

SciTech Connect

Geostatistics is extended to the spatial analysis of vector variables by defining the estimation variance and vector variogram in terms of the magnitude of difference vectors. Many random variables in geotechnology are in vectorial terms rather than scalars, and its structural analysis requires those sample variable interpolations to construct and characterize structural models. A better local estimator will result in greater quality of input models; geostatistics can provide such estimators; kriging estimators. The efficiency of geostatistics for vector variables is demonstrated in a case study of rock joint orientations in geological formations. The positive cross-validation encourages application of geostatistics to spatial analysis of random vectors in geoscience as well as various geotechnical fields including optimum site characterization, rock mechanics for mining and civil structures, cavability analysis of block cavings, petroleum engineering, and hydrologic and hydraulic modelings.

Young, D.S.

1987-08-01

36

Taming anomaly detection for industrial applications through spatial ponderation  

NASA Astrophysics Data System (ADS)

In recent years, an abundant number of applications have been developed for anomaly detection methods. Anomaly detection algorithms offer an easy and interpretable possibility to monitor the health state of virtually any technical system and industrial process that can be described by periodic measurements. But one major caveat remains: As all state-space methods, anomaly detection algorithms rely on measures of distance and these distances are distorted by any kind of irregularity in the data. The introduction of a spatial ponderation promises to cure this illness, but no mathematical foundation has been built to support this intuition. In this paper, first steps are introduced towards a stringent description of this approach.

Feller, Sebastian; Todorov, Yavor; Jaroszewski, Daniel; Chevalier, Roger

2013-10-01

37

WAX : A High Performance Spatial Auto-Correlation Application  

NASA Astrophysics Data System (ADS)

We describe the algorithms employed by WAX, a spatial auto-correlation application written in C and C++ which allows for both rapid grouping of multi-epoch apparitions as well as customizable statistical analysis of generated groups. The grouping algorithm, dubbed the swiss cheese algorithm, is designed to handle diverse input databases ranging from the 2MASS working point source database (an all sky database with relatively little coverage depth) to the 2MASS working calibration source database (a database with sparse but very deep coverage). WAX retrieves apparitions and stores groups directly from and to a DBMS, generating optimized C structures and ESQL/C code based on user defined retrieval and output columns. Furthermore, WAX allows generated groups to be spatially indexed via the HTM scheme and provides fast coverage queries for points and small circular areas on the sky. Finally, WAX operates on a declination based sky subdivision, allowing multiple instances to be run simultaneously and independently, further speeding the process of merging apparitions from very large databases. The Two Micron All Sky Survey will use WAX to create merged apparition catalogs from their working point and calibration source databases, linking generated groups to sources in the already publicly available all-sky catalogs. For a given 2MASS source, this will allow astronomers to examine the properties of many related (and as yet unpublished) 2MASS extractions, and further extends the scientific value of the 2MASS data sets.

Monkewitz, S.; Wheelock, S.

2005-12-01

38

Spatial and statistical GIS Applications for geological and environmental courses  

NASA Astrophysics Data System (ADS)

Building student's career through undergraduate and graduate courses integrated with modern statistical and GIS software foster a competitive curriculum for their future employment. We present examples that may be introduced in geological courses (e.g. mineralogy, geomorphology, geochronology, structural geology, tectonics, stratigraphy) and environmental courses (natural hazards, hydrology, atmospheric science). Univariate and multivariate statistical models can be used for the interpretation and mapping of the geological and environmental problems. Some of the main statistical univariate models such as the normal distribution as well as the multivariate methods such as the principal component analysis, cluster analysis and factor analysis are the basic methods for understanding the variables of the environmental and geological problems. Examples are presented describing the basic steps for the solution of the problems. Some of the geological problems in different scales are the interpretation of 3D structural data, identification of suitable outcrops for mapping shear sense kinematic indicators. categorical or cluster analysis on lineations depending on their origin, topology of mineral assemblages and spatial distribution of their c-axis, distinguishing paleo-elevations using cluster analysis in geomorphological structures using LiDAR intensity and elevation data for determination of meander evolution patterns and prediction of vulnerable sites for flooding or landsliding. Other applications in atmospheric and hydrology science are the prediction of ground level ozone and the decomposition of water use time series. Those fundamental statistical and spatial concepts may be used in the field or in the lab. In the lab, modern computers and friendly interface user software allow students to process data using advanced statistical methods and GIS techniques. Modern applications in tablets or smart phones may complement field work. Teaching those methods can facilitate advanced mapping, optimize sample collection distribution, field decisions, and later lab data processing.

Marsellos, A.; Tsakiri, K.

2012-12-01

39

OLAP Technology for Business Process Intelligence: Challenges and Solutions  

E-print Network

{Svetlana.Mansmann,Marc.Scholl}@uni-konstanz.de 2 University of Leipzig, Innovation Center Computer Assisted of business process management systems by employing data warehousing and mining technologies. However in the innovative application domain of Surgical Process Modeling. We describe the deficiencies of the conventional

Scholl, Marc H.

40

Unsupervised Spatial Event Detection in Targeted Domains with Applications to Civil Unrest Modeling  

E-print Network

Unsupervised Spatial Event Detection in Targeted Domains with Applications to Civil Unrest Modeling for monitoring and detecting events. Targeted domains such as crime, election, and social unrest require a novel unsupervised approach for detecting spatial events in targeted domains and illustrate

Ramakrishnan, Naren

41

Bayesian spatial transformation models with applications in neuroimaging data  

PubMed Central

Summary The aim of this paper is to develop a class of spatial transformation models (STM) to spatially model the varying association between imaging measures in a three-dimensional (3D) volume (or 2D surface) and a set of covariates. Our STMs include a varying Box-Cox transformation model for dealing with the issue of non-Gaussian distributed imaging data and a Gaussian Markov Random Field model for incorporating spatial smoothness of the imaging data. Posterior computation proceeds via an efficient Markov chain Monte Carlo algorithm. Simulations and real data analysis demonstrate that the STM significantly outperforms the voxel-wise linear model with Gaussian noise in recovering meaningful geometric patterns. Our STM is able to reveal important brain regions with morphological changes in children with attention deficit hyperactivity disorder. PMID:24128143

Miranda, Michelle F.; Zhu, Hongtu; Ibrahim, Joseph G.

2013-01-01

42

Spatial filtering efficiency of monostatic biaxial lidar: analysis and applications.  

PubMed

Results of lidar modeling based on spatial-angular filtering efficiency criteria are presented. Their analysis shows that the low spatial-angular filtering efficiency of traditional visible and near-infrared systems is an important cause of low signal/background-radiation ratio (SBR) at the photodetector input The low SBR may be responsible for considerable measurement errors and ensuing the low accuracy of the retrieval of atmospheric optical parameters. As shown, the most effective protection against sky background radiation for groundbased biaxial lidars is the modifying of their angular field according to a spatial-angular filtering efficiency criterion. Some effective approaches to achieve a high filtering efficiency for the receiving system optimization are discussed. PMID:12510915

Agishev, Ravil R; Comeron, Adolfo

2002-12-20

43

GIS application on spatial landslide analysis using statistical based models  

NASA Astrophysics Data System (ADS)

This paper presents the assessment results of spatially based probabilistic three models using Geoinformation Techniques (GIT) for landslide susceptibility analysis at Penang Island in Malaysia. Landslide locations within the study areas were identified by interpreting aerial photographs, satellite images and supported with field surveys. Maps of the topography, soil type, lineaments and land cover were constructed from the spatial data sets. There are ten landslide related factors were extracted from the spatial database and the frequency ratio, fuzzy logic, and bivariate logistic regression coefficients of each factor was computed. Finally, landslide susceptibility maps were drawn for study area using frequency ratios, fuzzy logic and bivariate logistic regression models. For verification, the results of the analyses were compared with actual landslide locations in study area. The verification results show that bivariate logistic regression model provides slightly higher prediction accuracy than the frequency ratio and fuzzy logic models.

Pradhan, Biswajeet; Lee, Saro; Buchroithner, Manfred F.

2009-09-01

44

Full Spatial Resolution Infrared Sounding Application in the Preconvection Environment  

NASA Astrophysics Data System (ADS)

Advanced infrared (IR) sounders such as the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) provide atmospheric temperature and moisture profiles with high vertical resolution and high accuracy in preconvection environments. The derived atmospheric stability indices such as convective available potential energy (CAPE) and lifted index (LI) from advanced IR soundings can provide critical information 1 ; 6 h before the development of severe convective storms. Three convective storms are selected for the evaluation of applying AIRS full spatial resolution soundings and the derived products on providing warning information in the preconvection environments. In the first case, the AIRS full spatial resolution soundings revealed local extremely high atmospheric instability 3 h ahead of the convection on the leading edge of a frontal system, while the second case demonstrates that the extremely high atmospheric instability is associated with the local development of severe thunderstorm in the following hours. The third case is a local severe storm that occurred on 7-8 August 2010 in Zhou Qu, China, which caused more than 1400 deaths and left another 300 or more people missing. The AIRS full spatial resolution LI product shows the atmospheric instability 3.5 h before the storm genesis. The CAPE and LI from AIRS full spatial resolution and operational AIRS/AMSU soundings along with Geostationary Operational Environmental Satellite (GOES) Sounder derived product image (DPI) products were analyzed and compared. Case studies show that full spatial resolution AIRS retrievals provide more useful warning information in the preconvection environments for determining favorable locations for convective initiation (CI) than do the coarser spatial resolution operational soundings and lower spectral resolution GOES Sounder retrievals. The retrieved soundings are also tested in a regional data assimilation WRF 3D-var system to evaluate the potential assist in the NWP model.

Liu, C.; Liu, G.; Lin, T.

2013-12-01

45

SPATIALLY VARIABLE INSECTICIDE APPLICATIONS FOR EARLY SEASON CONTROL OF COTTON INSECT PESTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Our research has shown that cotton insect pests, specifically tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae), can be controlled early season in commercial cotton fields in Mississippi, USA, using spatially variable insecticide applications. Technology was develo...

46

Relation Algebras and their Application in Temporal and Spatial Reasoning  

Microsoft Academic Search

Qualitative temporal and spatial reasoning is in many cases based on binary relations such as before, after, starts, contains, contact, part of, and others derived from these by relational operators. The calculus of relation algebras is an equational formalism; it tells us which relations must exist, given several basic operations, such as Boolean operations on relations, relational composition and converse.

Ivo Düntsch

2005-01-01

47

Nonparametric Spatial Models for Extremes: Application to Extreme Temperature Data*  

PubMed Central

Summary Estimating the probability of extreme temperature events is difficult because of limited records across time and the need to extrapolate the distributions of these events, as opposed to just the mean, to locations where observations are not available. Another related issue is the need to characterize the uncertainty in the estimated probability of extreme events at different locations. Although the tools for statistical modeling of univariate extremes are well-developed, extending these tools to model spatial extreme data is an active area of research. In this paper, in order to make inference about spatial extreme events, we introduce a new nonparametric model for extremes. We present a Dirichlet-based copula model that is a flexible alternative to parametric copula models such as the normal and t-copula. The proposed modelling approach is fitted using a Bayesian framework that allow us to take into account different sources of uncertainty in the data and models. We apply our methods to annual maximum temperature values in the east-south-central United States. PMID:24058280

Fuentes, Montserrat; Henry, John; Reich, Brian

2013-01-01

48

RADIO FREQUENCY INTERFERENCE REMOVAL THROUGH THE APPLICATION OF SPATIAL FILTERING TECHNIQUES ON THE PARKES MULTIBEAM RECEIVER  

SciTech Connect

This paper addresses the first practical application of spatial filtering techniques to data taken with a multibeam receiver. Spatial filters make use of the relative arrival times of a signal at multiple sensors to identify and separate signals from different directions. The method is a consequence of the Karhunen-Loeve theorem and relies on the eigen decomposition of the covariance matrix formed from the multiple signal paths. The effectiveness of the spatial filtering techniques is demonstrated on observations of the Vela pulsar taken with the Parkes 20 cm Multibeam receiver. The experiment was highly successful, and the results show spatial filtering methods provide powerful tools for interference mitigation with an array feed receiver. Extensions of the algorithm to reduce computational requirements and allow application on short (submillisecond) timescales are also explored.

Kocz, J.; Briggs, F. H. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT (Australia); Reynolds, J. [Commonwealth Scientific and Industrial Research Organisation, Epping, NSW (Australia)

2010-12-15

49

Distributed loss model: Application to a spatial turbopump inducer  

NASA Astrophysics Data System (ADS)

A three dimensional Euler flow computation in a spatial turbopump inducer with a distributed loss model at nominal flow rate is presented. The numerical results and the experimental ones are in good agreement. The loss model described uses a simple pitch averaged distribution of rotary stagnation pressure drop between hub and tip. A finely distributed loss model which can take into account global losses such as the effects of boundary layer on blades and the clearance gap ones is considered. Particular treatment of boundary conditions to simulate the rotation of the tip end wall is presented. One of the particularities of this method is to simulate back flow. The code CALECHE and the Clebsch-Hawthorne formulation are used. This code is also performed on a variety of isolate blade rows.

Elghazzani, E. M.; Bois, G.; Leboeuf, F.

50

Spatially explicit exposure models: application to military sites.  

PubMed

As a result of defense-related activities, large areas of valuable habitats can be physically disturbed and/or contaminated by hazardous pollutants. It is, however, important to understand that the military impact on such areas may not be wholly detrimental to the environment: their closure to the public can result in environmental conservation of large portions of habitat. Many former military ranges have been converted for civil usage; others are still actively operated for military purposes. In both cases, a major task for environmental policy- and decision-makers is to determine scientifically justified reuse and/or operation scenarios that would not result in deterioration of site habitats and that would in fact be favorable to further development of biodiversity within the areas' existing ecosystems. Ecological risk assessment is suggested as the key process to use in facilitating the assessment of the ecological value of contaminated and/or disturbed military sites and in the development of a reuse decision protocol. We are currently developing and integrating a number of risk and habitat assessment techniques into such a protocol. This paper presents our approach to one aspect of this system: the incorporation of spatial information into ecological risk assessment. We present a software prototype that calculates radionuclide accumulation by deer foraging in areas having specified contamination patterns. PMID:12539867

Linkov, I; Grebenkov, A; Baitchorov, V M

2001-06-01

51

Full-Stokes UV and visible spectropolarimeter for spatial application  

NASA Astrophysics Data System (ADS)

UVMag is a project of a space mission equipped with a high-resolution spectropolarimeter working in the UV and visible range. This M-size mission will be proposed to ESA. The main goal of UVMag is to measure the magnetic fields, winds and environment of all types of stars to reach a better understanding of stellar formation and evolution. The groundbreaking combination of a UV and visible observation will allow the scientists to study the star and its environment simultaneously. The baseline wavelength window for spectropolarimetry is between 117nm and 870nm, in order to observe the polarization state in many important spectral lines. We also aim at extending the window down to 90 nm at least in spectroscopy. The UV domain contains key atomic and molecular transitions, for example for hot stars, and is the best domain to study Sun-like stars or white dwarfs. The instrumental challenge for this mission is to design a high-resolution space spectropolarimeter measuring the full-Stokes vector of the observed star in a huge spectral range from FUV to the limit between visible and NIR. This spectral range is the main difficulty because of the lack of birefringent and transparent materials working at FUV and visible wavelengths at the same time. As the instrument will be launched into space, the polarimetry module has to be robust and therefore use if possible only static elements. I will present some concepts that we studied to build such a system, using spatial or temporal modulation or channeled polarimetry. The output of the full-Stokes robust polarimeter will correspond to the entrance slit of a high-resolution echelle spectrometer, which will disperse the echelle orders into several UV and visible detectors.

Pertenais, Martin; Neiner, Coralie; Petit, Pascal; Pares, Laurent

52

Research and Application on Network Update of Land Survey Spatial Data Based on Embedded GIS and GPS  

Microsoft Academic Search

This paper studies the methods and strategies of the network update of the land survey spatial data based on embedded terminal equipment and server and application of multi-level distributed heterogeneous land spatial database.Web services network model has been used to do the design and implementation work of embedded system of land survey data update. The main procedure of spatial data

Jian-Zhong Huang; Yao-Lin Liu; Yan-Fang Liu; Jian-Hua He; Dan Chen

2008-01-01

53

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

Microsoft Academic Search

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

Judo Yeo; R. Mittra

2002-01-01

54

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

PubMed

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

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

2014-03-01

55

A Spatial Econometric Approach to Measuring Pollution Externalities: An Application to Ozone Smog  

E-print Network

A Spatial Econometric Approach to Measuring Pollution Externalities: An Application to Ozone Smog C- ducing ozone smog. 1. Introduction In 1997, eight states in the northeastern United States filed Standard (NAAQS) for ozone smog. These petitions identified 31 states plus the District of Columbia

Lin, C.-Y. Cynthia

56

Progressive phase conjugation and its application in reconfigurable spatial-mode extraction and conversion  

NASA Astrophysics Data System (ADS)

We develop a new technology, which is referred to as progressive phase conjugation (PPC), in which phase conjugation is electrically performed without requiring a coherent reference beam by fusion using a reference-free spatial phase detection and spatial phase modulation. This method enables remote setting of a phase detector from the signal transmitter without an additional transmission line for the reference beam. It also enables realization of high-speed and dynamic wavefront compensation owing to its open-loop architecture using the single-shot phase detection method. Therefore, the PPC is applicable to a wide range of optical communication technologies, including the reconfigurable spatial-mode extraction and conversion of mode transmission in a multi-mode fiber (MMF). In our experiment, spatial modes are generated by directing a laser beam into a MMF with a 50-micron core diameter. At the output side of the optical fiber, the phase distributions of the spatial modes are detected using the reference-free phase detector constructed by combining a spatial filtering method with holographic diversity interferometry using two CCD imagers. Then, the phase conjugate distribution of the detected phase pattern is displayed on a LCOS-type SLM. We confirm that the PPC system can extract a specific mode pattern with a considerably low crosstalk of less than 1% by displaying the corresponding phase-conjugation pattern on the SLM. In addition, we demonstrated a reconfigurable spatial-mode conversion by the phase control technology using the SLM. By applying the spatial phase modulation to an optical beam incident on the SLM, the spatial mode of the output beam is flexibly changed.

Okamoto, Atsushi; Maeda, Tomohiro; Hirasaki, Yuki; Tomita, Akihisa; Sato, Kunihiro

2014-05-01

57

Hybrid modeling of spatial continuity for application to numerical inverse problems  

USGS Publications Warehouse

A novel two-step modeling approach is presented to obtain optimal starting values and geostatistical constraints for numerical inverse problems otherwise characterized by spatially-limited field data. First, a type of unsupervised neural network, called the self-organizing map (SOM), is trained to recognize nonlinear relations among environmental variables (covariates) occurring at various scales. The values of these variables are then estimated at random locations across the model domain by iterative minimization of SOM topographic error vectors. Cross-validation is used to ensure unbiasedness and compute prediction uncertainty for select subsets of the data. Second, analytical functions are fit to experimental variograms derived from original plus resampled SOM estimates producing model variograms. Sequential Gaussian simulation is used to evaluate spatial uncertainty associated with the analytical functions and probable range for constraining variables. The hybrid modeling of spatial continuity is demonstrated using spatially-limited hydrologic measurements at different scales in Brazil: (1) physical soil properties (sand, silt, clay, hydraulic conductivity) in the 42 km2 Vargem de Caldas basin; (2) well yield and electrical conductivity of groundwater in the 132 km2 fractured crystalline aquifer; and (3) specific capacity, hydraulic head, and major ions in a 100,000 km2 transboundary fractured-basalt aquifer. These results illustrate the benefits of exploiting nonlinear relations among sparse and disparate data sets for modeling spatial continuity, but the actual application of these spatial data to improve numerical inverse modeling requires testing.

Friedel, Michael J.; Iwashita, Fabio

2013-01-01

58

Spatial domain-based parallelism in large scale, participating-media, radiative transport applications  

SciTech Connect

Parallelism for gray participating media radiation heat transfer may be placed in two primary categories: spatial and angular domain-based parallelism. Angular, e.g., ray based, decomposition has received the greatest attention in the open literature for moderate sized applications where the entire geometry may be placed on processor. Angular based decomposition is limited, however, for large scale applications (O(10{sup 6}) to O(10{sup 8}) computational cells) given the memory required to store computational grids of this size on each processor. Therefore, the objective of this work is to examine the application of spatial domain-based parallelism to large scale, three-dimensional, participating-media radiation transport calculations using a massively parallel supercomputer architecture. Both scaled and fixed problem size efficiencies are presented for an application of the Discrete Ordinate method to a three dimensional, non-scattering radiative transport application with nonuniform absorptivity. The data presented shows that the spatial domain-based decomposition paradigm results in some degradation in the parallel efficiency but provides useful speedup for large computational grids.

Burns, S.P.; Christon, M.A.

1996-11-01

59

Assessing spatial resolution versus sensitivity from laser speckle contrast imaging: application to frequency analysis.  

PubMed

For blood perfusion monitoring, laser speckle contrast (LSC) imaging is a recent non-contact technique that has the characteristic of delivering noise-like speckled images. To exploit LSC images for quantitative physiological measurements, we developed an approach that implements controlled spatial averaging to reduce the detrimental impact of the noise and improve measurement sensitivity. By this approach, spatial resolution and measurement sensitivity can be traded-off in a flexible way depending on the quantitative prospect of the study. As an application, detectability of the cardiac activity from LSC images of forearm using power spectrum analysis is studied through the construction of spatial activity maps offering a window on the blood flow perfusion and its regional distribution. Comparisons with results obtained with signals of laser Doppler flowmetry probes are performed. PMID:22644256

Bricq, Stéphanie; Mahé, Guillaume; Rousseau, David; Humeau-Heurtier, Anne; Chapeau-Blondeau, François; Varela, Julio Rojas; Abraham, Pierre

2012-10-01

60

Existence and continuity of bi-spatial random attractors and application to stochastic semilinear Laplacian equations  

NASA Astrophysics Data System (ADS)

A concept of a bi-spatial random attractor for a random dynamical system is introduced. A unified result about existence and upper semi-continuity for a family of bi-spatial random attractors is obtained if a family of random systems is convergent, uniformly absorbing in an initial space and uniformly omega-compact in both initial and terminate spaces. The upper semi-continuity result improves all existing results even for single-spatial attractors. As an application of the abstract result, it is shown that every semilinear Laplacian equation on the entire space perturbed by a multiplicative and stochastic noise possesses an (L2 ,Lq)-random attractor with q > 2. Moreover, it is proved that the family of obtained attractors is upper semi-continuous at any density of noises and the family of attractors for the corresponding compact systems is both upper and lower semi-continuous at infinity under the topology of both spaces.

Li, Yangrong; Gu, Anhui; Li, Jia

2015-01-01

61

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

NASA Technical Reports Server (NTRS)

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.

Davis, Bruce E.; Elliot, Gregory

1989-01-01

62

Electro-optical properties of III-V compound semiconductors for spatial light modulation applications  

Microsoft Academic Search

The applicability of III-V compounds such as GaAs and InP and the related ternary and quaternary alloys to the fabrication of spatial light modulators (SLMs) for use in optical and hybrid computers is investigated, reviewing the results of recent experimental investigations. The fundamental principles of electroabsorption and electrorefraction in direct-bandgap semiconductors and multiple-quantum-well structures are explained; measurement results for several

William S. C. Chang; H. H. Wieder; T. E. van Eck; A. L. Kellner; P. Chu

1987-01-01

63

Spatial statistics and GIS application study in spatial variability analysis of house prices: a case study of Dongguan  

NASA Astrophysics Data System (ADS)

According as general houses' prices data, this paper, based on spatial analysis function of Geographic information system(GIS), using semi-variogram of spatial statistics, studies spatial heterogeneity of general houses' prices distribution in Dongguan quantitatively. The results from the analysis indicate: general houses' prices have both spatial autocorrelation and sometime local spatial heterogeneity, it can be found that the spatial distribution of general houses' prices takes on a zonal anisotropy by anisotropic variability analysis, which means that there are different structural characteristics in different directions for general houses' prices distribution; isotropic variability analysis reveals that: the semi-variogram of general houses' prices distribution in Dongguan is best described by spherical model, changes of general houses' prices distribution are affected by both structural and random factors; the ratio of random variance (nugget) to total variance(sill) is 37.5%, therefore the spatial correlation of general houses' prices is a kind of medium correlation with Nugget/Sill being between 25% - 75%, its spatial correlation range is 16.62 kilometres; the ratio of structure variance(partial sill) to total variance is higher than the ratio of random variance to total variance, this means that certain factors' contributions to the spatial variability of houses' prices is more than random factors' contributions.

Mei, Zhixiong; Ou, Yangjun; Hu, Weiping

2009-10-01

64

Application Composition based on WMS Layers for Supporting Spatial Data Infrastructure  

NASA Astrophysics Data System (ADS)

Web-based spatial data services are essential building blocks for Spatial Data Infrastructure (SDI). WMS, WFS and WCS are adopted increasingly to provide interoperable access to facilitate the integration of different web applications with a large number of data from various scientific domains. However, these services are widely dispersed and hard to be found, accessed, and utilized, this is especially true when we want to develop an application to mashing up multiple layers from multiple servers. To tackle this problem, we proposed a layer-based service oriented integration framework, focusing on the integration of distributed WMS resources, including 1) a Service Capabilities Clearing House (SCCH) to preprocess and store the services’ capability information of WMS, WFS and WCS. 2) a layer-based search engine with spatial, temporal and performance criteria to find more accurate records. 3) API and layer-based metadata to make the framework open and interoperable. 4) Customized 2-D, 3-D, and 4-D visualization interface for application integration. Acknowledgement: The research is supported by FGDC 2009 CAP program (project # G09AC00103, http://www.cisc.gmu.edu/projects/portal4gos.htm)

Li, Z.; Wu, H.; Yang, C.

2009-12-01

65

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

PubMed Central

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

2012-01-01

66

Application of spatial and angular domain based parallelism to a discrete ordinates formulation with unstructured spatial discretization  

Microsoft Academic Search

A parallel discrete ordinate formulation employing a general, unstructured finite element spatial discretization is presented for steady, gray, nonscattering radiative heat transport within a participating medium. The formulation is based on the first order form of the boltzmann transport equation and allows for any combination of spatial and angular domain based parallelism. The formulation is tested on a massively parallel,

1997-01-01

67

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

68

Applicability and efficiency of near-optimal spatial encoding for dynamically adaptive MRI.  

PubMed

Adaptive near-optimal MRI spatial encoding entails, for the acquisition of each image update in a dynamic series, the computation of encodes in the form of a linear algebra-derived orthogonal basis set determined from an image estimate. The origins of adaptive encoding relevant to MRI are reviewed. Sources of error of this approach are identified from the linear algebraic perspective where MRI data acquisition is viewed as the projection of information from the field-of-view onto the encoding basis set. The definitions of ideal and non-ideal encoding follow, with nonideal encoding characterized by the principal angles between two vector spaces. An analysis of the distribution of principal angles is introduced and applied in several example cases to quantitatively describe the suitability of a basis set derived from a specific image estimate for the spatial encoding of a given field-of-view. The robustness of adaptive near-optimal spatial encoding for dynamic MRI is favorably shown by results computed using singular value decomposition encoding that simulates specific instances of worst case data acquisition when all objects have changed or new objects have appeared in the field-of-view. The mathematical analysis and simulations presented clarify the applicability and efficiency of adaptively determined near-optimal spatial encoding throughout a range of circumstances as may typically occur during use of dynamic MRI. PMID:9469703

Zientara, G P; Panych, L P; Jolesz, F A

1998-02-01

69

New spatial localizer based on fiber optics with applications in 3D ultrasound imaging  

NASA Astrophysics Data System (ADS)

Spatial localizers provide a reference coordinate system and make the tracking of various objects in 3D space feasible. A number of different spatial localizers are currently available. Several factors that determine the suitability of a position sensor for a specific clinical application are accuracy, ease of use, and robustness of performance when used in a clinical environment. In this paper, we present a new and low-cost sensor with performance unaffected by a the materials present in the operating environment. This new spatial localizer consists of a flexible tape with a number of fiber optic sensor along its length. The main idea is that we can obtain the position and orientation of the end of the tape with respect to its base. The end and base of the tape are locations along its length determined by the physical location of the fiber optic sensors. Using this tape, we tracked an ultrasound probe and formed 3D US data sets. In order to validate the geometric accuracy of those 3D data sets, we measured known volumes of water-filled balloons. Our results indicate that we can measure volumes with accuracy between 2-16 percent. Given the fact that the sensor is under further development and refinement, we expect that this sensor could be an accurate, cost-effective and robust alternative in many medical applications, e.g., image-guided surgery and 3D ultrasound imaging.

Pagoulatos, Niko; Rohling, Robert N.; Edwards, Warren S.; Kim, Yongmin

2000-04-01

70

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

NASA Astrophysics Data System (ADS)

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.

Luo, Ji

2012-08-01

71

High dimensional spatial modeling of extremes with applications to United States Rainfalls  

NASA Astrophysics Data System (ADS)

Spatial statistical models are used to predict unobserved variables based on observed variables and to estimate unknown model parameters. Extreme value theory(EVT) is used to study large or small observations from a random phenomenon. Both spatial statistics and extreme value theory have been studied in a lot of areas such as agriculture, finance, industry and environmental science. This dissertation proposes two spatial statistical models which concentrate on non-Gaussian probability densities with general spatial covariance structures. The two models are also applied in analyzing United States Rainfalls and especially, rainfall extremes. When the data set is not too large, the first model is used. The model constructs a generalized linear mixed model(GLMM) which can be considered as an extension of Diggle's model-based geostatistical approach(Diggle et al. 1998). The approach improves conventional kriging with a form of generalized linear mixed structure. As for high dimensional problems, two different methods are established to improve the computational efficiency of Markov Chain Monte Carlo(MCMC) implementation. The first method is based on spectral representation of spatial dependence structures which provides good approximations on each MCMC iteration. The other method embeds high dimensional covariance matrices in matrices with block circulant structures. The eigenvalues and eigenvectors of block circulant matrices can be calculated exactly by Fast Fourier Transforms(FFT). The computational efficiency is gained by transforming the posterior matrices into lower dimensional matrices. This method gives us exact update on each MCMC iteration. Future predictions are also made by keeping spatial dependence structures fixed and using the relationship between present days and future days provided by some Global Climate Model(GCM). The predictions are refined by sampling techniques. Both ways of handling high dimensional covariance matrices are novel to analyze large data sets with extreme value distributions involved. One of the main outcomes of this model is for producing N-year return values and return years for a given value for precipitation at a single location given climate model projections based on a grid. This is very important, because in many applications, detailed precipitation information on pointwise locations is more important that predictions averaged over grids. The second model can be applied to those large data sets and is based on transformed Gaussian processes. These processes are thresholded due to the emphasis on rainfall extremes. Keywords. Block Circulant Matrix; Extreme value theory; Fast Fourier Transform; Generalized Linear Mixed Model; Kriging; Markov Chain Monte Carlo; Spectral Representation; Spatial statistics

Zhou, Jie

2007-12-01

72

Using Polarization to Control the Phase of Spatial Modes for Application in Quantum Information  

NASA Astrophysics Data System (ADS)

Exploiting spatial modes and polarization, we experimentally demonstrate the realization of a conditional ?-phase shift. Our approach is based on an optical circuit where the polarization and transverse degrees of freedom control the Gouy phase which is applied on Hermite-Gaussian beams. Our results show good wo-qubit states has beengood agreement with the simulation of the optical circuit. As an application, we propose the implementation of a two-qubit quantum phase gate, where the qubits are encoded on the Hermite-Gaussian modes and linear polarization states.

Balthazar, W. F.; Caetano, D. P.; Souza, C. E. R.; Huguenin, J. A. O.

2014-12-01

73

Application of Image Analysis for Characterization of Spatial Arrangements of Features in Microstructure  

NASA Technical Reports Server (NTRS)

A number of microstructural processes are sensitive to the spatial arrangements of features in microstructure. However, very little attention has been given in the past to the experimental measurements of the descriptors of microstructural distance distributions due to the lack of practically feasible methods. We present a digital image analysis procedure to estimate the micro-structural distance distributions. The application of the technique is demonstrated via estimation of K function, radial distribution function, and nearest-neighbor distribution function of hollow spherical carbon particulates in a polymer matrix composite, observed in a metallographic section.

Louis, Pascal; Gokhale, Arun M.

1995-01-01

74

Spatial and Temporal Simulation of Human Evolution. Methods, Frameworks and Applications  

PubMed Central

Analyses of human evolution are fundamental to understand the current gradients of human diversity. In this concern, genetic samples collected from current populations together with archaeological data are the most important resources to study human evolution. However, they are often insufficient to properly evaluate a variety of evolutionary scenarios, leading to continuous debates and discussions. A commonly applied strategy consists of the use of computer simulations based on, as realistic as possible, evolutionary models, to evaluate alternative evolutionary scenarios through statistical correlations with the real data. Computer simulations can also be applied to estimate evolutionary parameters or to study the role of each parameter on the evolutionary process. Here we review the mainly used methods and evolutionary frameworks to perform realistic spatially explicit computer simulations of human evolution. Although we focus on human evolution, most of the methods and software we describe can also be used to study other species. We also describe the importance of considering spatially explicit models to better mimic human evolutionary scenarios based on a variety of phenomena such as range expansions, range shifts, range contractions, sex-biased dispersal, long-distance dispersal or admixtures of populations. We finally discuss future implementations to improve current spatially explicit simulations and their derived applications in human evolution. PMID:25132795

Benguigui, Macarena; Arenas, Miguel

2014-01-01

75

A novel artificial immune algorithm for spatial clustering with obstacle constraint and its applications.  

PubMed

An important component of a spatial clustering algorithm is the distance measure between sample points in object space. In this paper, the traditional Euclidean distance measure is replaced with innovative obstacle distance measure for spatial clustering under obstacle constraints. Firstly, we present a path searching algorithm to approximate the obstacle distance between two points for dealing with obstacles and facilitators. Taking obstacle distance as similarity metric, we subsequently propose the artificial immune clustering with obstacle entity (AICOE) algorithm for clustering spatial point data in the presence of obstacles and facilitators. Finally, the paper presents a comparative analysis of AICOE algorithm and the classical clustering algorithms. Our clustering model based on artificial immune system is also applied to the case of public facility location problem in order to establish the practical applicability of our approach. By using the clone selection principle and updating the cluster centers based on the elite antibodies, the AICOE algorithm is able to achieve the global optimum and better clustering effect. PMID:25435862

Sun, Liping; Luo, Yonglong; Ding, Xintao; Zhang, Ji

2014-01-01

76

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

USGS Publications Warehouse

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.

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

2004-01-01

77

Generalized Taylor-Aris dispersion in discrete spatially periodic networks: Microfluidic applications  

NASA Astrophysics Data System (ADS)

A theory is presented for the lumped parameter, convective-diffusive transport of individual, noninteracting Brownian solute particles (``macromolecules'') moving within spatially periodic, solvent-filled networks-the latter representing models of chip-based microfluidic chromatographic separation devices, as well as porous media. Using graph-theoretical techniques, the composite medium is conceptually decomposed into a network of channels (the edges) through which the solute is transported by a combination of molecular diffusion and either ``piggyback'' entrainment within a flowing solvent or an externally applied force field acting upon the solute molecules. A probabilistic choice of egress channel for a solute particle exiting the intersection (vertex) of the channels is furnished by an imperfect mixing model. A spatially periodic, Taylor-Aris-like ``method-of-moments'' scheme is applied to this transport model, leading to discrete matrix equations for computing the network-scale particle velocity vector U¯* and dispersivity dyadic Dbar* in terms of the prescribed microscale transport parameters and network geometry characterizing the basic unit cell of which the spatially periodic device is comprised. The ensuing algebraic equations governing the vertex-based, discrete unit-cell ``fields'' P?0(i) and B(i) (i=1,2,...,n), whose paradigmatic summations yield U¯* and Dbar*, constitute discrete analogs of classical continuous macrotransport phenomenological parameters, P?0(r) and B(r), with r a continuous position vector defined within the unit cell. The ease with which these discrete calculations can be performed for complex networks renders feasible parametric studies of potential microfluidic chip designs, particularly those pertinent to biomolecular separation schemes. Application of this discrete theory to the dispersion analysis of pressure-driven flow in spatially periodic serpentine microchannels is shown to accord with existing results previously derived using classical continuous macrotransport theory.

Dorfman, Kevin D.; Brenner, Howard

2002-02-01

78

Development of spatial density maps based on geoprocessing web services: application to tuberculosis incidence in Barcelona, Spain  

PubMed Central

Background Health professionals and authorities strive to cope with heterogeneous data, services, and statistical models to support decision making on public health. Sophisticated analysis and distributed processing capabilities over geocoded epidemiological data are seen as driving factors to speed up control and decision making in these health risk situations. In this context, recent Web technologies and standards-based web services deployed on geospatial information infrastructures have rapidly become an efficient way to access, share, process, and visualize geocoded health-related information. Methods Data used on this study is based on Tuberculosis (TB) cases registered in Barcelona city during 2009. Residential addresses are geocoded and loaded into a spatial database that acts as a backend database. The web-based application architecture and geoprocessing web services are designed according to the Representational State Transfer (REST) principles. These web processing services produce spatial density maps against the backend database. Results The results are focused on the use of the proposed web-based application to the analysis of TB cases in Barcelona. The application produces spatial density maps to ease the monitoring and decision making process by health professionals. We also include a discussion of how spatial density maps may be useful for health practitioners in such contexts. Conclusions In this paper, we developed web-based client application and a set of geoprocessing web services to support specific health-spatial requirements. Spatial density maps of TB incidence were generated to help health professionals in analysis and decision-making tasks. The combined use of geographic information tools, map viewers, and geoprocessing services leads to interesting possibilities in handling health data in a spatial manner. In particular, the use of spatial density maps has been effective to identify the most affected areas and its spatial impact. This study is an attempt to demonstrate how web processing services together with web-based mapping capabilities suit the needs of health practitioners in epidemiological analysis scenarios. PMID:22126392

2011-01-01

79

Management and research applications of real-time and archival passive acoustic sensors over varying temporal and spatial scales  

Microsoft Academic Search

Defining the appropriate scale over which to conduct a study in the marine environment is critical to achieving appropriate scientific, management, mitigation and conservation objectives. This paper focuses on applications of passive acoustic technologies over a range of spatial and temporal scales. It is divided into sections dealing with archival and real-time passive acoustic sensor applications. Each section assesses the

Sofie M. Van Parijs; Chris W. Clark; Renata S. Sousa-Lima; Susan E. Parks; Shannon Rankin; Denise Risch; Ilse C. Van Opzeeland

2009-01-01

80

Application of spatial and angular domain based parallelism to a discrete ordinates formulation with unstructured spatial discretization  

SciTech Connect

A parallel discrete ordinate formulation employing a general, unstructured finite element spatial discretization is presented for steady, gray, nonscattering radiative heat transport within a participating medium. The formulation is based on the first order form of the boltzmann transport equation and allows for any combination of spatial and angular domain based parallelism. The formulation is tested on a massively parallel, distributed memory architecture using a standard three-dimensional benchmark calculation. The results show that the formulation presented provides better parallel performance and accuracy than the author`s previously published work. The ultimate objective of both the current and previous efforts is to develop a computationally efficient radiative transport model for use in large scale numerical fire simulations.

Burns, S.P. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center

1997-08-01

81

Application of Spatially Resolved High Resolution Crystal Spectrometry to ICF Plasmas  

SciTech Connect

High resolution (?/?#3;? ~ 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.

Kenneth W. Hill, et. al.

2012-09-15

82

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmasa)  

NASA Astrophysics Data System (ADS)

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 55Fe 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.

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

83

A spatial application of a vegetation productivity equation for neo-soil reconstruction  

SciTech Connect

Reclamation specialists are interested in the application of recently developed soil productivity equations for post-mining reclamation planning and design. This paper presents the application of one recently developed soil productivity equation to a surface coal mine site in Mercer County, North Dakota. Geographic information systems (GIS) technology (Map*Factory 1.1) was combined with a soil productivity equation developed by the author to generate a GIS script to calculate a site's pre-mining productivity per 10 meter grid cell and then summed to calculate the grand and the expected average soil productivity for the site, resulting in a pre-mining baseline numerical spatial scores. Several post-mining alternatives were evaluated to study various soil management strategies to restore post-mining soil productivity, including: an abandoned mine landscape treatment, a reconstructed topsoil treatment with graded gentile slopes, and a reconstructed topsoil treatment with soil improvements. The results indicated that the abandoned mine scenario was significantly different than the other three treatments (p{le}0.05), with the reconstructed topsoil treatment with soil amendments generating the greatest estimated productivity.

Burley, J.B.

1999-07-01

84

An efficient algorithm for spatially-correlated random fields generation and its applications on the two-phase material  

NASA Astrophysics Data System (ADS)

The properties of material strongly depend on the microstructure, and the development of microstructure is closely related to the phase transition with the temperature-dependent spatial correlation. To consider more realistic microstructures, we have proposed an efficient and simple algorithm for generating the spatially-correlated random field, which is obtained by the weighted average of random fields without spatial correlation according to the spatially-correlated length and anisotropy parameter. By using a mesoscale finite element model with the microstructures generated by our algorithm, an application study on the effective elastic behavior of Al2O3-NiAl composite materials is given. Our numerical results are in agreement with the experimental measurements. The proposed method is general and robust, which can be extended to the multi-phase materials.

Tang, Xin-Wei; Yang, Xiao-Bao; Zhou, Yuan-De

2014-03-01

85

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

86

Using Geo-Spatial Technologies for Field Applications in Higher Geography Education  

ERIC Educational Resources Information Center

Today's important geo-spatial technologies, GIS (Geographic Information Systems), GPS (Global Positioning Systems) and Google Earth have been widely used in geography education. Transferring spatially oriented data taken by GPS to the GIS and Google Earth has provided great benefits in terms of showing the usage of spatial technologies for field…

Karatepe, Akif

2012-01-01

87

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

NASA Astrophysics Data System (ADS)

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.

Nichols, Patricia

88

Estimation of Amino Acid Residue Substitution Rates at Local Spatial Regions and Application in Protein Function Inference: A Bayesian  

E-print Network

Estimation of Amino Acid Residue Substitution Rates at Local Spatial Regions and Application of Bioengineering, Science and Engineering Offices, MC-063, University of Illinois at Chicago The amino acid and for predicting protein functions. Estimating the rate matrix of residue substitutions from amino acid sequences

Dai, Yang

89

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...

90

A spatially distributed energy balance snowmelt model for application in mountain basins  

USGS Publications Warehouse

Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required for successful water and resource management. A coupled energy and mass-balance model ISNOBAL is used to simulate the development and melting of the seasonal snowcover in several mountain basins in California, Idaho, and Utah. Simulations are done over basins varying from 1 to 2500 km2, with simulation periods varying from a few days for the smallest basin, Emerald Lake watershed in California, to multiple snow seasons for the Park City area in Utah. The model is driven by topographically corrected estimates of radiation, temperature, humidity, wind, and precipitation. Simulation results in all basins closely match independently measured snow water equivalent, snow depth, or runoff during both the development and depletion of the snowcover. Spatially distributed estimates of snow deposition and melt allow us to better understand the interaction between topographic structure, climate, and moisture availability in mountain basins of the western US. Application of topographically distributed models such as this will lead to improved water resource and watershed management.Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required for successful water and resource management. A coupled energy and mass-balance model ISNOBAL is used to simulate the development and melting of the seasonal snowcover in several mountain basins in California, Idaho, and Utah. Simulations are done over basins varying from 1 to 2500 km2, with simulation periods varying from a few days for the smallest basin, Emerald Lake watershed in California, to multiple snow seasons for the Park City area in Utah. The model is driven by topographically corrected estimates of radiation, temperature, humidity, wind, and precipitation. Simulation results in all basins closely match independently measured snow water equivalent, snow depth, or runoff during both the development and depletion of the snowcover. Spatially distributed estimates of snow deposition and melt allow us to better understand the interaction between topographic structure, climate, and moisture availability in mountain basins of the western US. Application of topographically distributed models such as this will lead to improved water resource and watershed management.

Marks, D.; Domingo, J.; Susong, D.; Link, T.; Garen, D.

1999-01-01

91

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

NASA Astrophysics Data System (ADS)

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 an atmospheric link. It has been examined carefully with most analyses considering the Gaussian Schell-model (GSM) beam. However, practical PCBs may not follow GSM theory and are better examined through some numerical simulation approach such as a wave optics simulation. Consequently, an approach for modeling the spatially PCB in wave optics simulation is presented here. 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 (GSM) beam. A variety of simulation studies were performed for this dissertation. The propagation through turbulence of a coherent beam and a particular version of a PCB, a pseudo-partially coherent beam (PPCB), is analyzed. The beam is created with a sequence of several Gaussian random phase screens for each atmospheric realization. The average intensity profiles, the scintillation index and aperture averaging factor for a horizontal propagation scenario are examined. Comparisons between these results and their corresponding analytic results for the well-known GSM beam are also made. Cumulative probability density functions for the received irradiance are initially investigated. Following the general simulation investigations, a performance metric is proposed as a general measure for optimizing the transverse coherence length of a partial spatially coherent beam for a given communication scenario. The expression is essentially the mean intensity minus the standard deviation of the intensity and we seek to maximize this quantity. This measure is preliminarily verified through a comparison with the probability of fade assuming the log-normal distribution model under the weak turbulence condition. The measure is also examined as a function of coherence length using wave optics simulations and these results are compared with relationships predicted by analytic theory under weak to medium-strong turbulence conditions. These results indicate there exists a unique coherence length that can optimize the receiver beam quality. Moreover, by taking the derivative of this quantity with respect to the atmospheric transverse coherence length and setting the result to zero, a result is obtained that indicates the near-optimal partially coherent beam for a given lasercom system. Finally, the analytical theory of the probability density function of the received irradiance and the probability of fade for the log-normal and Gamma- Gamma distributions was extended for partially coherent beams propagating through arbitrary atmospheric turbulence. In addition, wave optics simulations were carried out for horizontal propagations of Gaussian Schell-model beams for a variety of typical link parameters. The simulated irradiance values at the center of the received beam are used to estimate the probability density of the irradiance. The probability of fade was examined using the accumulative probability density from zero to a threshold level. The results derived from the simulation compare favorably with the corresponding analytical theory. The comparisons reveal that the Gamma-Gamma and log-normal distributions of probability density functions provide a good fit to the wave optics simulation results under weak and moderate-to-strong turbulence regimes, respectively. Yet, for the probability of fade, the wave optics simulation results show a transition from the Gamma-Gamma to log-normal distribution under weak to strong turbu

Xiao, Xifeng

92

A spatially distributed energy balance snowmelt model for application in mountain basins  

NASA Astrophysics Data System (ADS)

Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required for successful water and resource management. A coupled energy and mass-balance model ISNOBAL is used to simulate the development and melting of the seasonal snowcover in several mountain basins in California, Idaho, and Utah. Simulations are done over basins varying from 1 to 2500 km2, with simulation periods varying from a few days for the smallest basin, Emerald Lake watershed in California, to multiple snow seasons for the Park City area in Utah. The model is driven by topographically corrected estimates of radiation, temperature, humidity, wind, and precipitation. Simulation results in all basins closely match independently measured snow water equivalent, snow depth, or runoff during both the development and depletion of the snowcover. Spatially distributed estimates of snow deposition and melt allow us to better understand the interaction between topographic structure, climate, and moisture availability in mountain basins of the western US. Application of topographically distributed models such as this will lead to improved water resource and watershed management.

Marks, Danny; Domingo, James; Susong, Dave; Link, Tim; Garen, David

1999-09-01

93

Design and Development of an Open Source Software Application for the Characterization of Spatially Variable Fields  

NASA Astrophysics Data System (ADS)

The characterization of the structural parameters of spatially variable fields (SVFs) is essential to understanding the variability of hydrological processes such as infiltration, evapotranspiration, groundwater contaminant transport, etc. SVFs can be characterized using a Bayesian inverse method called Method of Anchored Distributions (MAD). This method characterizes the structural parameters of SVFs using prior information of structural parameter fields, indirect measurements, and simulation models allowing the transfer of valuable information to a target variable field. An example SVF in hydrology is hydraulic conductivity, which may be characterized by head pressure measurements through a simulation model such as MODFLOW. This poster will present the design and development of a free and open source inverse modeling desktop software application and extension framework called MAD# for the characterization of the structural parameters of SVFs using MAD. The developed software is designed with a flexible architecture to support different simulation models and random field generators and includes geographic information system (GIS) interfaces for representing, analyzing, and understanding SVFs. This framework has also been made compatible with Mono, a cross-platform implementation of C#, for a wider usability.

Gunnell, D. K.; Osorio-Murillo, C. A.; Over, M. W.; Frystacky, H.; Ames, D. P.; Rubin, Y.

2013-12-01

94

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

PubMed

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

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

2014-01-01

95

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

PubMed Central

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

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

2014-01-01

96

Graph OLAP: a multi-dimensional framework for graph data analysis  

Microsoft Academic Search

Databases and data warehouse systems have been evolving from handling normalized spreadsheets stored in relational databases,\\u000a to managing and analyzing diverse application-oriented data with complex interconnecting structures. Responding to this emerging\\u000a trend, graphs have been growing rapidly and showing their critical importance in many applications, such as the analysis of\\u000a XML, social networks, Web, biological data, multimedia data and spatiotemporal

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

2009-01-01

97

A method for spatial–temporal forecasting with an application to real estate prices  

Microsoft Academic Search

Using 5243 housing price observations during 1984–92 from Baton Rouge, this manuscript demonstrates the substantial benefits obtained by modeling the spatial as well as the temporal dependence of the errors. Specifically, the spatial–temporal autoregression with 14 variables produced 46.9% less SSE than a 12-variable regression using simple indicator variables for time. More impressively, the spatial–temporal regression with 14 variables displayed

R. Kelley Pace; Ronald Barry; Otis W. Gilley; C. F. Sirmans

2000-01-01

98

Spatial modeling of survival and residency and application to the Monitoring Avian Productivity and Survivorship program  

Microsoft Academic Search

Broad-scale bird-ringing programs are a core component of national and international avian monitoring and research efforts.\\u000a Despite rich spatial structure in data from these programs, little attention has been paid to spatial modeling of demographic\\u000a rates. Here we implemented a Bayesian analysis of a hierarchical capture–recapture model to provide spatially explicit (2°\\u000a blocks) and year-specific estimates of adult apparent survival

James F. SaraccoJ; J. Andrew Royle; David F. DeSante; Beth Gardner

99

The application of high spatial resolution remote sensing image for vegetation type recognition in Dagou Valley  

Microsoft Academic Search

This paper present a detail processing procedure about SPOT5 image applied for vegetation type recognition, and determines the capacity of high spatial resolution satellite image data to discriminate vegetation type in a complex ecosystem. A high spatial resolution SPOT5 image, captured in April 2005, and coincident field data covering the Dagou valley, was used in this analysis. Image geometric rectification

Aqiang Yang; Chuang Liu; Jianrong Fan; Jinling Zhao; Jing Tan

2008-01-01

100

Spatial pattern of 2009 dengue distribution in Kuala Lumpur using GIS application  

Microsoft Academic Search

In the last few years in Malaysia, dengue fever has increased dramatically and has caused huge public health concerns. The present study aimed to establish a spatial distribution of dengue cases in the city of Kuala Lumpur using a combination of Geographic Information System (GIS) and spatial statistical tools. Collation of data from 1,618 dengue cases in 2009 was obtained

S. Aziz; R. Ngui; Y. A. L. Lim; I. Sholehah; J. N. Farhana; A. S. Azizan; W. W. S. Yusoff

2012-01-01

101

Spatially distributed assessment of solar resources for energy applications in Slovakia  

Microsoft Academic Search

Spatial and temporal distribution of available solar energy depends on several factors. Besides latitude and astronomical factors it is strongly influenced by climate factors (e.g. cloudiness, turbidity) and topography. This paper presents a solar database of Slovakia containing spatially-distributed solar energy resource data necessary for planning, sitting and forecasting of solar device installations. The database consists of several data sets

Jaroslav HOFIERKA

2008-01-01

102

Estimating Treatment Effects from Spatial Policy Experiments: An Application to Ugandan Microfinance  

Microsoft Academic Search

This paper demonstrates a method for estimating treatment effects in spatial tests, utilizing a second control group to measure unexplained spatial phenomena. The technique is implemented on two innovations in Ugandan microfinance, and we measure the ways in which concurrent shocks such as an Ebola outbreak and a contentious presidential election altered outcomes differentially across regions. By correcting for this

Craig McIntosh

2008-01-01

103

Towards the geometric optimization of potential field models - A new spatial operator tool and applications  

NASA Astrophysics Data System (ADS)

We present a new method for automated geometric modifications of potential field models. Computational developments and the increasing amount of available potential field data, especially gradient data from the satellite missions, lead to increasingly complex models and integrated modelling tools. Editing of these models becomes more difficult. Our approach presents an optimization tool that is designed to modify vertex-based model geometries (e.g. polygons, polyhedrons, triangulated surfaces) by applying spatial operators to the model that use an adaptive, on-the-fly model discretization. These operators deform the existing model via vertex-dragging, aiming at a minimized misfit between measured and modelled potential field anomaly. The parameters that define the operators are subject to an optimization process. This kind of parametrization provides a means for the reduction of unknowns (dimensionality of the search space), allows a variety of possible modifications and ensures that geometries are not destroyed by crossing polygon lines or punctured planes. We implemented a particle swarm optimization as a global searcher with restart option for the task of finding optimal operator parameters. This approach provides us with an ensemble of model solutions that allows a selection and geologically reasonable interpretations. The applicability of the tool is demonstrated in two 2D case studies that provide models of different extent and with different objectives. The first model is a synthetic salt structure in a horizontally layered background model. Expected geometry modifications are considerably small and localized and the initial models contain rather little information on the intended salt structure. A large scale example is given in the second study. Here, the optimization is applied to a sedimentary basin model that is based on seismic interpretation. With the aim to evaluate the seismically derived model, large scale operators are applied that mainly cause depth adjustments to the model horizons.

Haase, Claudia; Götze, Hans-Jürgen

2014-05-01

104

Application of spatial features to satellite land-use analysis. [spectral signature variations  

NASA Technical Reports Server (NTRS)

A Level I land-use analysis of selected training areas of the Colorado Front Range was carried out using digital ERTS-A satellite imagery. Level I land-use categories included urban, agriculture (irrigated and dryland farming), rangeland, and forests. The spatial variations in spectral response for these land-use classes were analyzed using discrete two-dimensional Fourier transforms to isolate and extract spatial features. Analysis was performed on ERTS frame 1352-17134 (July 10, 1973) and frame number 1388-17131 (August 15, 1973). On training sets, spatial features yielded 80 to 100 percent classification accuracies with commission errors ranging from 0 to 20 percent.

Smith, J.; Hornung, R.; Berry, J.

1975-01-01

105

Spatial pattern of 2009 dengue distribution in Kuala Lumpur using GIS application.  

PubMed

In the last few years in Malaysia, dengue fever has increased dramatically and has caused huge public health concerns. The present study aimed to establish a spatial distribution of dengue cases in the city of Kuala Lumpur using a combination of Geographic Information System (GIS) and spatial statistical tools. Collation of data from 1,618 dengue cases in 2009 was obtained from Kuala Lumpur City Hall (DBKL). These data were processed and then converted into GIS format. Information on the average monthly rainfall was also used to correlate with the distribution pattern of dengue cases. To asses the spatial distribution of dengue cases, Average Nearest Neighbor (ANN) Analysis was applied together with spatial analysis with the ESRI ArcGIS V9.3 programme. Results indicated that the distribution of dengue cases in Kuala Lumpur for the year 2009 was spatially clustered with R value less than 1 (R = 0.42; z-scores = - 4.47; p < 0.001). Nevertheless, when this pattern was further analyzed according to month by each zone within Kuala Lumpur, two distinct patterns were observed which include a clustered pattern (R value < 1) between April to June and a dispersed pattern (R value > 1) between August and November. In addition, the mean monthly rainfall has not influenced the distribution pattern of the dengue cases. Implementation of control measures is more difficult for dispersed pattern compared to clustered pattern. From this study, it was found that distribution pattern of dengue cases in Kuala Lumpur in 2009 was spatially distributed (dispersed or clustered) rather than cases occurring randomly. It was proven that by using GIS and spatial statistic tools, we can determine the spatial distribution between dengue and population. Utilization of GIS tools is vital in assisting health agencies, epidemiologist, public health officer, town planner and relevant authorities in developing efficient control measures and contingency programmes to effectively combat dengue fever. PMID:22543611

Aziz, S; Ngui, R; Lim, Y A L; Sholehah, I; Nur Farhana, J; Azizan, A S; Wan Yusoff, W S

2012-03-01

106

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

USGS Publications Warehouse

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).

Preston, Stephen D.; Brakebill, John W.

1999-01-01

107

A bayesian analysis for spatial processes with application to disease mapping.  

PubMed

In epidemiology, maps of disease rates and disease risk provide a spatial perspective for researching disease aetiology. For rare diseases or when the population base is small, the rate and risk estimates may be unstable. We propose using a Bayesian analysis based on the conditional autoregressive (CAR) process that will spatially smooth disease rates or risk estimates by allowing each site to 'borrow strength' from its neighbours. Covariates may be included in the model in such a way as to establish a possible association between risk factors and disease incidence. Bayesian inferences are implemented from a direct resampling scheme where large samples are generated from the various posterior distributions. The methodology is demonstrated with a simulation that assesses the effect of sample size and the model parameters on inferences for the parameters. Our approach is also used to spatially smooth district lip cancer rates in Scotland using the CAR model with a covariate that allows for exposure to sunlight. PMID:10750062

Bell, B S; Broemeling, L D

2000-04-15

108

Violent crime in San Antonio, Texas: an application of spatial epidemiological methods.  

PubMed

Violent crimes are rarely considered a public health problem or investigated using epidemiological methods. But patterns of violent crime and other health conditions are often affected by similar characteristics of the built environment. In this paper, methods and perspectives from spatial epidemiology are used in an analysis of violent crimes in San Antonio, TX. Bayesian statistical methods are used to examine the contextual influence of several aspects of the built environment. Additionally, spatial regression models using Bayesian model specifications are used to examine spatial patterns of violent crime risk. Results indicate that the determinants of violent crime depend on the model specification, but are primarily related to the built environment and neighborhood socioeconomic conditions. Results are discussed within the context of a rapidly growing urban area with a diverse population. PMID:22748228

Sparks, Corey S

2011-12-01

109

Modeling the environmental suitability of recreational trails in the Sam Houston National Forest: an application of spatial technologies and the universal soil loss equation  

E-print Network

MODELING THE ENVIRONMENTAL SUITABILITY OF RECREATIONAL TRAILS IN THE SAM HOUSTON NATIONAL FOREST: AN APPLICATION OF SPATIAL TECHNOLOGIES AND THE UNIVERSAL SOIL LOSS EQUATION A Thesis by DAMON MICHAEL HOLZER Submitted to the Office of Graduate... HOUSTON NATIONAL FOREST: AN APPLICATION OF SPATIAL TECHNOLOGIES AND THE UNIVERSAL SOIL LOSS EQUATION A Thesis by DAMON MICHAEL HOLZER Submitted to Texas ASSAM University in partial fulfillment of the requirements for the degree of MASTER...

Holzer, Damon Michael

1997-01-01

110

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

Microsoft Academic Search

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

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

2000-01-01

111

HOW TO SAMPLE TO CALIBRATE A SPATIAL MODEL: APPLICATION FOR MODELLING  

E-print Network

to the vineyard variability. The goal of this work is to calibrate a spatial model by coupling high quality, high management practices, and consequently to differentiate and improve grape and wine quality [2]. There is quality, high cost related attributes [3]. Between those high quality vine measurements, plant water

Paris-Sud XI, Université de

112

Development and application of a spatially-distributed Arctic hydrological and thermal process model (ARHYTHM)  

Microsoft Academic Search

A process-based, spatially distributed hydrological model was developed to quantitatively simulate the energy and mass transfer processes and their interactions within arctic regions (arctic hydrological and thermal model, ARHYTHM). The model first determines the flow direction in each element, the channel drainage network and the drainage area based upon the digital elevation data. Then it simulates various physical processes: including

Ziya Zhang; Douglas L. Kane; Larry D. Hinzman

2000-01-01

113

Analysis of nonintrinsic spatial variability by residual kriging with application to regional groundwater levels  

Microsoft Academic Search

A method for obtaining pointwise or spatially averaged estimates of a nonintrinsic function is introduced based on residual kriging. The method relies on a stepwise iterative regression process for simultaneously estimating the global drift and residual semivariogram. Estimates of the function are then obtained by solving a modified set of simple kriging equations written for the residuals. The modification consists

Shlomo P. Neuman; Elizabeth A. Jacobson

1984-01-01

114

Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling  

USGS Publications Warehouse

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.

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

2011-01-01

115

Application of spatial analysis to the examination of dengue fever in Guayaquil, Ecuador  

Microsoft Academic Search

Dengue is the main viral disease transmitted by arthropods worldwide with over 50 million people infected yearly, especially in tropical and subtropical regions. In Ecuador epidemics of dengue erupted since 2000 with the appearance of the hemorrhagic form. However, studies in urban areas to better understand the spatial distribution of the disease are lacking. The objective of this study was

Katty C. Castillo; Birthe Körbl; Anna Stewart; Javier F. Gonzalez; Facundo Ponce

2011-01-01

116

Transmissive spatial light modulators with high figure-of-merit liquid crystals for foveated imaging applications  

E-print Network

Transmissive spatial light modulators with high figure-of- merit liquid crystals for foveated for foveated imaging systems that provide wide field-of-view (FOV) coverage (±60° in azimuth and elevation-resolution SLMs. Transmissive SLM operation allows the foveated imaging configuration to be very compact using

Wu, Shin-Tson

117

Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling1  

PubMed Central

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

Brakebill, JW; Wolock, DM; Terziotti, SE

2011-01-01

118

VISUALIZING SPATIAL PROCESSES USING RIPLEY'S CORRECTION: AN APPLICATION TO BODILY-INJURY CAR  

E-print Network

and motivation In order to improve road safety and to reduce traffic accidents, public authorities have to understand when and where traffic accident occurred. Analysis of spatial pat- terns is then a crucial issue, since it is difficult to assume that occurrences of traffic accidents are purely random observations

Paris-Sud XI, Université de

119

VISUALIZING SPATIAL PROCESSES USING RIPLEY'S CORRECTION: AN APPLICATION TO BODILY-INJURY CAR  

E-print Network

road safety and to reduce traffic accidents, public authorities have to understand when and where traffic accident occurred. Analysis of spatial patterns is then a crucial issue, since it is difficult to assume that occurrences of traffic accidents are purely random observations, in space and time. In most

Paris-Sud XI, Université de

120

A Simulation Study to Investigate Spatial Representativeness Errors in Lognormal Fields: Application to Rainfall  

NASA Astrophysics Data System (ADS)

In the large majority of studies on the evaluation of radar-rainfall estimates, rain gauge measurements have been used to approximate the ground-level true rainfall. Nevertheless, as extensively documented in the literature, this approximation leads to an additional source of uncertainty due to the large sampling discrepancies between the two measuring devices: radar data are area-averaged estimates while rain gauges can be considered as point measurements. In this study, the sampling or representativeness error is defined as the ratio between areal and point estimates. By means of simulation of spatially correlated lognormally distributed fields, the authors provide additional insight into the error statistical distribution, spatial correlation and dependence on the field magnitude values. The results presented are based on spatial configuration of four actual rain gauge networks located in the United States (Iowa, Kansas and Oklahoma) and a fictitious random network with different gauge densities. This setup provides the flexibility to investigate the effects of different configurations and gauge densities. In addition, the authors apply a spatial averaging geostatistical tool, i.e. block kriging, to transform rain gauge measurements into areal estimates, and demonstrate how this results in a reduction of the representativeness error.

Villarini, G.; Mandapaka, P. V.; Krajewski, W. F.; Ciach, G. J.

2006-12-01

121

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...

122

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

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

123

Modulation Properties of a Twisted Nematic Liquid Crystal Spatial Light Modulator and its Applications in a Joint Transform Correlator  

NASA Astrophysics Data System (ADS)

The spatial light modulator is one of the key elements in a real time optical signal processing architecture. Within the past five or six years, a commercially available twisted nematic type liquid crystal television (LCTV) has emerged as a popular spatial light modulator. This inexpensive, electrical addressable device has been shown to be very effective in performing various optical signal processing applications. This thesis investigates the modulation properties of this device and its applications in a joint transform correlator (JTC). The twisted nematic liquid crystal cell is well known for its polarization property. However, the phase modulation property due to the birefringence of the nematic liquid crystal is equally important. Through extensive experimental studies, it is found that the liquid crystal television under investigation can indeed provide more than 2pi of phase modulation. Using the phase modulation property of an LCTV and a point diffraction interferometer, we propose and demonstrate an iterative technique for phase correction of an optical system. This technique is a fully programmable, active, and on-line process which has the capability of performing wavefront restoration in real time. Attention is then turned to the application of the LCTV in a JTC architecture. We discuss several real time joint transform correlation systems using various spatial light modulators. The final stage of our research study is to apply a JTC in a target tracking problem. The correlator is made adaptive to the environment by using the target images in the previous frame of a motion sequence as the reference images. The system is thus able to handle dynamic targets tracking under scale, rotation, and perspective distortions.

Tam, Eddy Chipoon

124

[Effects of wheat-oilseed rape intercropping and methyl salicylate application on the spatial distributions of Sitobion avenae and its main natural enemies].  

PubMed

A field investigation was conducted on the spatial distributions of Sitobion avenae and its main natural enemies under wheat-oilseed rape intercropping and methyl salicylate application. With the development of wheat plant, an alternation from aggregation to uniform was observed in the spatial distribution of S. avenae under the intercropping and methyl salicylate application, being more obvious under the interaction of the two practices. The spatial distribution of S. avenae natural enemies was in accordance with that of the aphid. These results could be used for the reference of sampling investigation and forecast of wheat aphid and its natural enemies in field. PMID:23173471

Dong, Jie; Liu, Ying-Jie; Wang, Guang; Liu, Yong

2012-07-01

125

High-fidelity spatially resolved multiphoton counting for quantum imaging applications  

E-print Network

We present a method for spatially resolved multiphoton counting based on an intensified camera with the retrieval of multimode photon statistics fully accounting for non-linearities in the detection process. The scheme relies on one-time quantum tomographic calibration of the detector. Faithful, high-fidelity reconstruction of single- and two-mode statistics of multiphoton states is demonstrated for coherent states and their statistical mixtures. The results consistently exhibit classical values of Mandel and Fano parameters in contrast to raw statistics of camera photo-events. Detector operation is reliable for illumination levels up to the average of one photon per an event area, substantially higher than in previous approaches to characterize quantum statistical properties of light with spatial resolution.

Radoslaw Chrapkiewicz; Wojciech Wasilewski; Konrad Banaszek

2014-05-17

126

Generalized Taylor-Aris dispersion in discrete spatially periodic networks: Microfluidic applications  

Microsoft Academic Search

A theory is presented for the lumped parameter, convective-diffusive transport of individual, noninteracting Brownian solute particles (``macromolecules'') moving within spatially periodic, solvent-filled networks-the latter representing models of chip-based microfluidic chromatographic separation devices, as well as porous media. Using graph-theoretical techniques, the composite medium is conceptually decomposed into a network of channels (the edges) through which the solute is transported by

Kevin D. Dorfman; Howard Brenner

2002-01-01

127

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

Microsoft Academic Search

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

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

2001-01-01

128

Characterizing Spatial Parameters of Forest Canopies Using Fisheye Photography: Applications in Photo Ecometrics  

Microsoft Academic Search

Five case studies are presented that demonstrate how metrics inferred from canopy photography can inform and validate the results from digital aerial photography and other remote sensing platforms. The forests measured include evergreen and deciduous canopies composed of both needle-leaved and broad-leaved tree species. Gap fractions of these forest canopies ranged from 3% to 22%. Significant fine-scale spatial autocorrelation of

John J. Battles

1999-01-01

129

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

Microsoft Academic Search

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

Zhipeng Xu; Jun Wei; Jianwei Li; Qianting Zhou

2010-01-01

130

Detection of spatial clusters: application to cancer survival as a continuous outcome.  

PubMed

In this article, we develop the first detailed illustration of the use of a cluster detection method using a spatial scan statistic based on an exponential survival model. We use this approach to study the spatial patterns of survival of patients with stage III or stage IV colorectal cancer or with stage I/II, stage III, or stage IV lung cancer in the State of California and the County of Los Angeles (LA) diagnosed during 1988 through 2002. We present the location of the detected clusters of short survival or long survival and compute nonparametric estimates of survival inside and outside of those detected clusters confirming the survival pattern detected by the spatial scan statistic in both areas. In LA County, we investigate the possible relationship between the cluster locations and race, sex, and histology using nonparametric methods, and we compare socioeconomic factors such as education, employment, income, and health insurance inside and outside of the detected clusters. Finally, we evaluate the effect of related covariates on statistically significant long and short survival clusters detected in LA County using logistic regression models. This article illustrates a new way to understand survival patterns that may point to health disparities in terms of diagnosis and treatment patterns. PMID:17179759

Huang, Lan; Pickle, Linda W; Stinchcomb, David; Feuer, Eric J

2007-01-01

131

MALDI Imaging Mass Spectrometry (MALDI-IMS)—Application of Spatial Proteomics for Ovarian Cancer Classification and Diagnosis  

PubMed Central

MALDI imaging mass spectrometry (MALDI-IMS) allows acquisition of mass data for metabolites, lipids, peptides and proteins directly from tissue sections. IMS is typically performed either as a multiple spot profiling experiment to generate tissue specific mass profiles, or a high resolution imaging experiment where relative spatial abundance for potentially hundreds of analytes across virtually any tissue section can be measured. Crucially, imaging can be achieved without prior knowledge of tissue composition and without the use of antibodies. In effect MALDI-IMS allows generation of molecular data which complement and expand upon the information provided by histology including immuno-histochemistry, making its application valuable to both cancer biomarker research and diagnostics. The current state of MALDI-IMS, key biological applications to ovarian cancer research and practical considerations for analysis of peptides and proteins on ovarian tissue are presented in this review. PMID:21340013

Gustafsson, Johan O. R.; Oehler, Martin K.; Ruszkiewicz, Andrew; McColl, Shaun R.; Hoffmann, Peter

2011-01-01

132

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

PubMed

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

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

133

Pattern classification of fMRI data: applications for analysis of spatially distributed cortical networks.  

PubMed

The field of fMRI data analysis is rapidly growing in sophistication, particularly in the domain of multivariate pattern classification. However, the interaction between the properties of the analytical model and the parameters of the BOLD signal (e.g. signal magnitude, temporal variance and functional connectivity) is still an open problem. We addressed this problem by evaluating a set of pattern classification algorithms on simulated and experimental block-design fMRI data. The set of classifiers consisted of linear and quadratic discriminants, linear support vector machine, and linear and nonlinear Gaussian naive Bayes classifiers. For linear discriminant, we used two methods of regularization: principal component analysis, and ridge regularization. The classifiers were used (1) to classify the volumes according to the behavioral task that was performed by the subject, and (2) to construct spatial maps that indicated the relative contribution of each voxel to classification. Our evaluation metrics were: (1) accuracy of out-of-sample classification and (2) reproducibility of spatial maps. In simulated data sets, we performed an additional evaluation of spatial maps with ROC analysis. We varied the magnitude, temporal variance and connectivity of simulated fMRI signal and identified the optimal classifier for each simulated environment. Overall, the best performers were linear and quadratic discriminants (operating on principal components of the data matrix) and, in some rare situations, a nonlinear Gaussian naïve Bayes classifier. The results from the simulated data were supported by within-subject analysis of experimental fMRI data, collected in a study of aging. This is the first study that systematically characterizes interactions between analysis model and signal parameters (such as magnitude, variance and correlation) on the performance of pattern classifiers for fMRI. PMID:24705202

Yourganov, Grigori; Schmah, Tanya; Churchill, Nathan W; Berman, Marc G; Grady, Cheryl L; Strother, Stephen C

2014-08-01

134

A new spatially constrained NMF with application to fMRI.  

PubMed

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

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

2011-01-01

135

Joint Variable Spatial Downscaling (JVSD): A New Downscaling Method with Application to the Southeast US  

NASA Astrophysics Data System (ADS)

Joint Variable Spatial Downscaling (JVSD) is a new downscaling method developed to produce high resolution gridded hydrological datasets suitable for regional watershed modeling and assessments. JVSD differs from other statistical downscaling methods in that multiple climatic variables are downscaled simultaneously to produce realistic and consistent climate fields. JVSD includes two major steps: bias correction and spatial downscaling. In the bias correction step, JVSD uses a differencing process to create stationary joint cumulative frequency statistics of the variables being downscaled. Bias correction is then based on quantile-to-quantile mapping of these stationary frequency distributions probability space. The functional relationship between these statistics and those of the historical observation period is subsequently used to remove GCM bias. The original variables are recovered through summation of bias corrected differenced sequences. In the spatial disaggregation step, JVSD uses a historical analogue approach, with historical analogues identified simultaneously for all atmospheric fields and over all areas of the basin under study. Analysis and comparisons with 20th Century Climate in Coupled Models (20C3M) data show that JVSD reproduces the sub-grid climatic features as well as their temporal/spatial variability in the historical periods. Comparisons are also performed for precipitation and temperature with the North American regional climate change assessment program (NARCCAP) and other statistical downscaling methods over the southeastern US. The results show that JVSD performs favorably. JVSD is applied for all A1B and A2 CMIP3 GCM scenarios in the Apalachicola-Chattahoochee-Flint River Basin (southeast US) with the following general findings: (i) Mean monthly temperature exhibits increasing trends over the ACF basin for all seasons and all A1B and A2 scenarios; Most significant are the A2 temperature increases in the 2050 - 2099 time periods; (ii) In the southern ACF watersheds, mean precipitation generally exhibits a mild decline in early spring and summer and increases in late winter; For the northern ACF watersheds, mean precipitation decreases in summer and increases mildly in winter (as in the south); (iii) In addition to mean trends, the precipitation distributions stretch on both ends with higher highs (floods) and lower lows (droughts). The downscaled temperature and precipitation scenarios are the basis of a comprehensive hydrologic and water resources assessment (reported elsewhere) assessing significant water, agricultural, energy, and environmental sector impacts and underscoring the need for mitigation and adaptation measures.

Zhang, F.; Georgakakos, A. P.

2011-12-01

136

Bayesian Models for Spatial Extremes Application to inferring high values of  

E-print Network

­ models block maxima · GPD ­ models threshold exceedances #12;Generalized Pareto Distribution [Pickands- son. · Build up the distribution of the FHDA. Naive Model · Straightforward application of kriging

Gilleland, Eric

137

Geo-spatial Service and Application based on National E-government Network Platform and Cloud  

NASA Astrophysics Data System (ADS)

With the acceleration of China's informatization process, our party and government take a substantive stride in advancing development and application of digital technology, which promotes the evolution of e-government and its informatization. Meanwhile, as a service mode based on innovative resources, cloud computing may connect huge pools together to provide a variety of IT services, and has become one relatively mature technical pattern with further studies and massive practical applications. Based on cloud computing technology and national e-government network platform, "National Natural Resources and Geospatial Database (NRGD)" project integrated and transformed natural resources and geospatial information dispersed in various sectors and regions, established logically unified and physically dispersed fundamental database and developed national integrated information database system supporting main e-government applications. Cross-sector e-government applications and services are realized to provide long-term, stable and standardized natural resources and geospatial fundamental information products and services for national egovernment and public users.

Meng, X.; Deng, Y.; Li, H.; Yao, L.; Shi, J.

2014-04-01

138

Development and application of a spatial hydrology model of Okefenokee Swamp, Georgia  

USGS Publications Warehouse

The model described herein was used to assess effects of the Suwannee River sill (a low earthen dam constructed to impound the Suwannee River within the Okefenokee National Wildlife Refuge to eliminate wildfires) on the hydrologic environment of Okefenokee Swamp, Georgia. Developed with Arc/Info Macro Language routines in the GRID environment, the model distributes water in the swamp landscape using precipitation, inflow, evapotranspiration, outflow, and standing water. Water movement direction and rate are determined by the neighborhood topographic gradient, determined using survey grade Global Positioning Systems technology. Model data include flow rates from USGS monitored gauges, precipitation volumes and water levels measured within the swamp, and estimated evapotranspiration volumes spatially modified by vegetation type. Model output in semi-monthly time steps includes water depth, water surface elevation above mean sea level, and movement direction and volume. Model simulations indicate the sill impoundment affects 18 percent of the swamp during high water conditions when wildfires are scarce and has minimal spatial effect (increasing hydroperiods in less than 5 percent of the swamp) during low water and drought conditions when fire occurrence is high but precipitation and inflow volumes are limited.

Loftin, C.S.; Kitchens, W.M.; Ansay, N.

2001-01-01

139

Temporal and spatial variation of surface reaction rates in porous media: Applications to silicate weathering  

NASA Astrophysics Data System (ADS)

Percolation theory provides a promising framework for modeling transport in heterogeneous porous media, including hydraulic and electrical conductivity, air permeability, gas diffusivity, and solute transport. Using percolation concepts (e.g., critical path analysis, fractal scaling of percolation clusters, and cluster statistics), we developed a physically-based model for predicting solute transport. Our model predicted spatial solute distributions as a function of time, and arrival time distributions as a function of system size. Our solute transport predictions gave good matches to a wide range of experiments. We now apply our solute transport model to silicate weathering. We assume that surface chemical reactions are at equilibrium at the scale of a single pore, but that at larger length scales, reactions are limited by transport of reactants or products. Using results from published field experiments, we find that the temporal and spatial dependence derived from solute velocity successfully predicts the measured time- and length-dependence of reaction rates and weathering of silicate minerals over a wide range of time and length scale. A similar analysis of lab experiments (uranium breakthrough curves measured in two short and long columns from the Hanford site) indicates that normalized reaction rate versus normalized time follow 2D invasion and 3D random percolation.

Ghanbarian, B.; Hunt, A. G.; Skinner, T. E.; Ewing, R. P.

2013-12-01

140

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

PubMed

We present a mobile device for the quantification of the small-scale (a few square meters) spatial variability in the surface energy balance components and several auxiliary variables of short-statured (<1 m) canopies. The key element of the mobile device is a handheld 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 (1) land use and (2) slope and aspect of the underlying surface, (3) controls on landscape-scale variability in soil temperature and albedo and (4) the estimation of evapotranspiration based exclusively on measurements with the mobile device. PMID:25063050

Wohlfahrt, Georg; Tasser, Erich

2014-07-26

141

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

NASA Astrophysics Data System (ADS)

This paper presents the Spatially Explicit Hydrologic Response (SEHR) model developed at the Laboratory of Ecohydrology of the Ecole Polytechnique Fédérale de Lausanne for the simulation of hydrological processes at the catchment scale. The key concept of the model is the formulation of water transport by geomorphologic travel time distributions through gravity-driven transitions among geomorphic states: 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 model thus breaks down the complexity of the hydrologic response into an explicit geomorphological combination of dominant spatial patterns of precipitation input and of hydrologic process controls. Nonstationarity and nonlinearity effects are tackled through soil moisture dynamics in the active soil layer. We present here the basic model set-up for precipitation-runoff simulation and a detailed discussion of its parameter estimation and of its performance for the Dischma River (Switzerland), a snow-dominated catchment with a small glacier cover.

Schaefli, B.; Nicótina, L.; Imfeld, C.; Da Ronco, P.; Bertuzzo, E.; Rinaldo, A.

2014-11-01

142

Application of Geo-Spatial Techniques for Precise Demarcation of Village/Panchayat Boundaries  

NASA Astrophysics Data System (ADS)

In order to achieve the overall progress of the country with active and effective participation of all sections of society, the 12th Five Year Plan (FYP) would bring Panchayats centre-stage and achieve the inclusive growth agenda through inclusive governance. The concept of 'democratic decentralization' in the form of a three-tier administration was introduced in the name of "Panchayat Raj". Horizontally, it is a network of village Panchayats. Vertically, it is an organic growth of Panchayats rising up to national level. The Ministry of Panchayati Raj has three broad agenda: Empowerment, Enablement and Accountability. Space based Information Support for Decentralized Planning (SIS-DP) is one of the initiatives taken by Govt. of India with ISRO/DOS for generation and dissemination of spatial information for planning at the grass root level. The boundary layer for villages across different states/district/block is available with line departments. Most of these data exist at a much generalized scale. These boundaries do not overlay exactly with that of ground realities and may not be suitable for accurate analysis in terms of area, shape, position, etc. To deal with this problem, a strategy is adopted, which makes use of High Resolution Satellite Imagery (HRSI) from Indian Remote sensing satellites and cadastral maps at 1:4000 scale integrated with GIS techniques to enhance the accuracy of geo-spatial depiction of Village/Panchayat boundaries. Cadastral maps are used to depict the boundaries of land parcels and other features at the village level. These maps are registered to ortho products of HRSI using Ground Control Points. The cadastral maps are precisely overlaid on ortho-rectified HRSI and each parcel vertex is tagged with the real-world geographical coordinates. Village boundaries are extracted from the geo-referenced village cadastral maps. These boundaries are fine-tuned by considering under lap and overlap of neighboring villages and a mosaic is generated at the subdistrict and district level. Each village is coded with a unique number based on Ministry of Panchayati Raj and Census department codes. Villages are mapped to their respective Panchayat(s) directory and are dissolved in GIS environment based on code/nomenclature to obtain the final Gram Panchayat Layer. The present study attempts to showcase the methodology for deriving precise Village/Panchayat Boundaries using geo-spatial techniques. The final output will immensely help the Ministry of Panchayati Raj and Rural Development for implementing the developmental programs in tune with 73th and 74th constitutional amendments.

Rao, S. S.; Banu, V.; Tiwari, A.; Bahuguna, S.; Uniyal, S.; Chavan, S. B.; Murthy, M. V. R.; Arya, V. S.; Nagaraja, R.; Sharma, J. R.

2014-11-01

143

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

USGS Publications Warehouse

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.

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

1994-01-01

144

Transmissive spatial light modulators with high figure-of-merit liquid crystals for foveated imaging applications  

NASA Astrophysics Data System (ADS)

Unique liquid crystal (LC) spatial light modulators (SLM) are being developed for foveated imaging systems that provide wide field-of-view (FOV) coverage (+/-60° in azimuth and elevation) without requiring gimbals or other mechanical scanners. Recently, a transmissive-SLM- based system operating in the visible (532 nm) has been demonstrated. The LC SLM development is addressing implementation issues through the development of high figure-of-merit (FoM) LC materials and transmissive high-resolution SLMs. Transmissive SLM operation allows the foveated imaging configuration to be very compact using a very simple lens system. The reduction in the size, weight and cost of the imaging optics and in data acquisition/processing hardware makes the foveated approach attractive for small platforms such as unmanned airborne vehicles (UAVs) or missile seekers.

Harriman, Jamie; Gauza, Sebastian; Wu, Shin-Tson; Wick, David; Bagwell, Brett; Martinez, Ty; Payne, Don; Serati, Steven

2006-02-01

145

Development and application of an instrument for spatially resolved Seebeck coefficient measurements  

NASA Astrophysics Data System (ADS)

The Seebeck coefficient is a key indicator of the majority carrier type (electrons or holes) in a material. The recent trend toward the development of combinatorial materials research methods has necessitated the development of a new high-throughput approach to measuring the Seebeck coefficient at spatially distinct points across any sample. The overall strategy of the high-throughput experiments is to quickly identify the region of interest on the sample at some expense of accuracy, and then study this region by more conventional techniques. The instrument for spatially resolved Seebeck coefficient measurements reported here relies on establishing a temperature difference across the entire compositionally graded thin-film and consecutive mapping of the resulting voltage as a function of position, which facilitates the temperature-dependent measurements up to 400 °C. The results of the designed instrument are verified at ambient temperature to be repeatable over 10 identical samples and accurate to within 10% versus conventional Seebeck coefficient measurements over the -100 to +150 ?V/K range using both n-type and p-type conductive oxides as test cases. The developed instrument was used to determine the sign of electrical carriers of compositionally graded Zn-Co-O and Ni-Co-O libraries prepared by combinatorial sputtering. As a result of this study, both cobalt-based materials were determined to have p-type conduction over a broad single-phase region of chemical compositions and small variation of the Seebeck coefficient over the entire investigated range of compositions and temperature.

Zakutayev, Andriy; Luciano, Frank J.; Bollinger, Vincent P.; Sigdel, Ajaya K.; Ndione, Paul F.; Perkins, John D.; Berry, Joseph J.; Parilla, Philip A.; Ginley, David S.

2013-05-01

146

Thermal Characterization of Defects in Aircraft Structures Via Spatially Controlled Heat Application  

NASA Technical Reports Server (NTRS)

Recent advances in thermal imaging technology have spawned a number of new thermal NDE techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a matter of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post-processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. The National Aeronautics and Space Administration's Langley Research Center has developed a thermal NDE technique designed to image a number of potential flaws in aircraft structures. The technique involves injecting a small, spatially controlled heat flux into the outer surface of an aircraft. Images of fatigue cracking, bond integrity and material loss due to corrosion are generated from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. Spatial tailoring of the heat coupled with the analysis techniques represent a significant improvement in the delectability of flaws over conventional thermal imaging. Results of laboratory experiments on fabricated crack, disbond and material loss samples will be presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling. The experimental results will be compared with these models to demonstrate the utility of such an approach.

Cramer, K. Elliott; Winfree, William P.

1997-01-01

147

Thermal characterization of defects in aircraft structures via spatially controlled heat application  

NASA Astrophysics Data System (ADS)

Recent advances in thermal imaging technology have spawned a number of new thermal NDE techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a matter of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post- processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. The National Aeronautics and Space Administrations's Langley Research Center has developed a thermal NDE technique designed to image a number of potential flaws in aircraft structures. The technique involves injecting a small, spatially controlled heat flux into the outer surface of an aircraft. Images of fatigue cracking, bond integrity and material loss due to corrosion are generated from measurements of the induced surface temperature variations. This paper presents a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. Spatial tailoring of the heat coupled with the analysis techniques represent a significant improvement in the detectability of flaws over conventional thermal imaging. Results of laboratory experiments on fabricated crack, disbond and material loss samples are presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling. The experimental results are compared with these models to demonstrate the utility of such an approach.

Cramer, K. Elliott; Winfree, William P.

1996-03-01

148

Classification and spatial mapping of riparian habitat with applications toward management of streams impacted by nonpoint source pollution  

NASA Astrophysics Data System (ADS)

Management of riparian habitats has been recognized for its importance in reducing instream effects of agricultural nonpoint source pollution. By serving as a buffer, well structured riparian habitats can reduce nonpoint source impacts by filtering surface runoff from field to stream. A system has been developed where key characteristics of riparian habitat, vegetation type, height, width, riparian and shoreline bank slope, and land use are classified as discrete categorical units. This classification system recognizes seven riparian vegetation types, which are determined by dominant plant type. Riparian and shoreline bank slope, in addition to riparian width and height, each consist of five categories. Classification by discrete units allows for ready digitizing of information for production of spatial maps using a geographic information system (GIS). The classification system was tested for field efficiency on Tom Beall Creek watershed, an agriculturally impacted third-order stream in the Clearwater River drainage, Nez Perce County, Idaho, USA. The classification system was simple to use during field applications and provided a good inventory of riparian habitat. After successful field tests, spatial maps were produced for each component using the Professional Map Analysis Package (pMAP), a GIS program. With pMAP, a map describing general riparian habitat condition was produced by combining the maps of components of riparian habitat, and the condition map was integrated with a map of soil erosion potential in order to determine areas along the stream that are susceptible to nonpoint source pollution inputs. Integration of spatial maps of riparian classification and watershed characteristics has great potential as a tool for aiding in making management decisions for mitigating off-site impacts of agricultural nonpoint source pollution.

Delong, Michael D.; Brusven, Merlyn A.

1991-07-01

149

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

PubMed Central

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

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

150

A novel capacitance sensor principle applicable for spatially resolving downhole measurements  

Microsoft Academic Search

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

Gert Holler; Thomas Thurner; Hubert Zangl; Georg Brasseur

2002-01-01

151

Improved coupling to integrated spatial heterodyne spectrometers with applications to space  

Microsoft Academic Search

Multiple Aperture Transform Chip Heterodyne (MATCH) spectrometers have been developed for targeted remote sensing applications in harsh environments. These waveguide-based Fourier Transform Spectrometers (FTS) offer significant improvements in resource efficiency over monolithic glass implementations, but are relatively limited in terms of input coupling efficiency and fill factor of the input facet. Integrated optics spectrometers have significant resource advantages for space

A. Scott; P. Bock; C. A. Ramos; B. Lamontagne; P. Cheben; M. Florjanczyk; I. M. Fernandez; S. Janz; A. Ortega-Monux; B. Solheim; D.-X. Xu

2011-01-01

152

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

NASA Astrophysics Data System (ADS)

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.

Gkatzoflias, Dimitrios; Mellios, Giorgos; Samaras, Zissis

2013-03-01

153

Application of the Brixton spatial anticipation test in stroke: ecological validity and performance characteristics.  

PubMed

Executive dysfunction predicts functional recovery post-stroke. However, traditional neuropsychological tests have limitations with this population due to required verbal response, complex motor response, and lengthy administration time. This study examined the ecological validity and performance characteristics of a relatively new measure of executive function, the Brixton Spatial Anticipation Test, which does not place the aforementioned demands on these patients. A total of 57 ischemic stroke patients with frontal lobe and subcortical lesions were administered the Brixton, on average 2 weeks post-stroke, during inpatient rehabilitation and assessed using the Functional Independence Measure (FIM) upon discharge. Brixton performance was significantly correlated with the FIM Total and FIM Cognitive Subtotal at discharge but unrelated to FIM Motor Subtotal. After controlling for global ability measured by the RBANS, Brixton performance accounted for additional variance in predicting FIM Total score at discharge. Interestingly, patients with subcortical strokes in the thalamus and basal ganglia performed significantly worse than patients with strokes in the frontal cortex on the Brixton, supporting the role of subcortical structures in the frontal lobe circuitry and executive function. Based on the present findings, the Brixton is a sensitive measure conducive to the stroke population and has strong ecological validity for identifying cognitive functional outcomes post-stroke. PMID:24528244

Vordenberg, Jessica A; Barrett, John J; Doninger, Nicholas A; Contardo, Christopher P; Ozoude, Kingsley A

2014-01-01

154

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

SciTech Connect

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.

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

155

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

PubMed Central

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

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

2010-01-01

156

Natural, Persistent Oscillations in a Spatial Multi-Strain Disease System with Application to Dengue  

PubMed Central

Many infectious diseases are not maintained in a state of equilibrium but exhibit significant fluctuations in prevalence over time. For pathogens that consist of multiple antigenic types or strains, such as influenza, malaria or dengue, these fluctuations often take on the form of regular or irregular epidemic outbreaks in addition to oscillatory prevalence levels of the constituent strains. To explain the observed temporal dynamics and structuring in pathogen populations, epidemiological multi-strain models have commonly evoked strong immune interactions between strains as the predominant driver. Here, with specific reference to dengue, we show how spatially explicit, multi-strain systems can exhibit all of the described epidemiological dynamics even in the absence of immune competition. Instead, amplification of natural stochastic differences in disease transmission, can give rise to persistent oscillations comprising semi-regular epidemic outbreaks and sequential dominance of dengue's four serotypes. Not only can this mechanism explain observed differences in serotype and disease distributions between neighbouring geographical areas, it also has important implications for inferring the nature and epidemiological consequences of immune mediated competition in multi-strain pathogen systems. PMID:24204241

Lourenço, José; Recker, Mario

2013-01-01

157

Application of speed-enhanced spatial domain correlation filters for real-time security monitoring  

NASA Astrophysics Data System (ADS)

A speed enhanced space variant correlation filer which has been designed to be invariant to change in orientation and scale of the target object but also to be spatially variant, i.e. the filter function becoming dependant on local clutter conditions within the image. The speed enhancement of the filter is due to the use of optimization techniques employing low-pass filtering to restrict kernel movement to be within regions of interest. The detection and subsequent identification capability of the two-stage process has been evaluated in highly cluttered backgrounds using both visible and thermal imagery acquired from civil and defense domains along with associated training data sets for target detection and classification. In this paper a series of tests have been conducted in multiple scenarios relating to situations that pose a security threat. Performance matrices comprised of peak-to-correlation energy (PCE) and peak-to-side lobe ratio (PSR) measurements of the correlation output have been calculated to allow the definition of a recognition criterion. The hardware implementation of the system has been discussed in terms of Field Programmable Gate Array (FPGA) chipsets with implementation bottle necks and their solution being considered.

Gardezi, Akber; Bangalore, Nagachetan; Al-Kandri, Ahmed; Birch, Philip; Young, Rupert; Chatwin, Chris

2011-11-01

158

Application of a computable model of human spatial vision to phase discrimination  

NASA Technical Reports Server (NTRS)

A computable model of human spatial vision is used to make predictions for phase-discrimination experiments. This model is being developed to deal with a broad range of problems in vision and was not specifically formulated to deal with phase discrimination. In the model, cross-correlation of the stimuli with an array of sensors produces feature vectors that are operated on by a position-uncertain ideal observer to simulate detection and discrimination experiments. In this report, the stimuli are compound sinusoidal gratings composed of a fundamental and a higher-frequency component added in various phases. Model predictions are compared with three key results from the literature: (1) the effect of the contrast of the fundamental on phase discrimination, (2) threshold phase difference as a function of the fundamental frequency, and (3) the contrast required for phase discrimination as a function of the frequency ratio of the two grating components. In the first two cases, the predictions capture the main features of the data, although quantitative discrepancies remain. In the third case, the model fails, and this failure suggests additional restrictions on the combination of information across sensors.

Nielsen, K. R. K.; Watson, A. B.; Ahumada, A. J., Jr.

1985-01-01

159

Daily canopy photosynthesis model through temporal and spatial scaling for remote sensing applications  

Microsoft Academic Search

Because Farquhar’s photosynthesis model is only directly applicable to individual leaves instantaneously, considerable skill is needed to use this model for regional plant growth and carbon budget estimations. In many published models, Farquhar’s equations were applied directly to plant canopies by assuming a plant canopy to function like a big-leaf. This big-leaf approximation is found to be acceptable for estimating

J. M. Chen; J. Liu; J. Cihlar; M. L. Goulden

1999-01-01

160

Assessing the applicability of terrestrial laser scanning for spatial snow depth measurements  

Microsoft Academic Search

Snow depth observation in potentially dangerous avalanche-starting zones is important for avalanche prediction and dimensioning of permanent protection measures. The possible danger of avalanches complicates measurements of snow depth in the field (e.g. by probing). Therefore, the applicability of terrestrial laser scanning to measure the depth of the snow cover was analysed. Different long-range laser profile measuring systems were used

Alexander Prokop

2008-01-01

161

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

SciTech Connect

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.

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

1999-03-15

162

Frequency assessment of spatially distributed generations of flood scenarios: an application on Italian territory  

NASA Astrophysics Data System (ADS)

The flooding risk impact on society cannot be understated: it influences land use and territorial planning and development at both physical and regulatory levels. To cope with it, a variety of actions can be put in place, involving multidisciplinary competences. Mitigation measures goes from the improvement of monitoring systems to the development of hydraulic structures, throughout land use restrictions, civil protection and insurance plans. All of those options present social and economic impacts, either positive or negative, whose proper estimate should rely on the assumption of appropriate - present and future - scenarios, i.e. quantitative event descriptions in terms of i) the flood hazard, with its probability of occurrence, extension, intensity, and duration, ii) the exposed values and iii) their vulnerability. At present, initial attention has been devoted to the design of flood scenarios, or ensembles of them, and to the evaluation of their frequency of occurrence. In the present work, a model for spatially distributed flood scenarios generation and frequency assessment is proposed and applied to the Italian territory. The study area has been divided into homogeneous regions according to their hydrologic, orographic and meteoclimatic characteristics. A statistical model for flood scenarios simulation has been implemented throughout a conditional approach based on MCMC simulations by using i) a historical flood events catalogue; ii) a homogeneous regions correlation matrix; and iii) an auxiliary variables data set. In this framework, the role of the information stored in the historical flood events catalogue "Aree Vulnerate Italiane" (AVI, http://avi.gndci.cnr.it/), produced by the Italian National Research Council, is of crucial importance.

Lomazzi, M.; Roth, G.; Rudari, R.; Taramasso, A. C.; Ghizzoni, T.; Benedetti, R.; Espa, G.; Terpessi, C.

2009-12-01

163

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

NASA Astrophysics Data System (ADS)

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.

Lin, Alexander Justin

164

Application of spatial and non-spatial data analysis in determination of the factors that impact municipal solid waste generation rates in Turkey  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Spatial autocorrelation exists in municipal solid waste generation rates for different provinces in Turkey. Black-Right-Pointing-Pointer Traditional non-spatial regression models may not provide sufficient information for better solid waste management. Black-Right-Pointing-Pointer Unemployment rate is a global variable that significantly impacts the waste generation rates in Turkey. Black-Right-Pointing-Pointer Significances of global parameters may diminish at local scale for some provinces. Black-Right-Pointing-Pointer GWR model can be used to create clusters of cities for solid waste management. - Abstract: In studies focusing on the factors that impact solid waste generation habits and rates, the potential spatial dependency in solid waste generation data is not considered in relating the waste generation rates to its determinants. In this study, spatial dependency is taken into account in determination of the significant socio-economic and climatic factors that may be of importance for the municipal solid waste (MSW) generation rates in different provinces of Turkey. Simultaneous spatial autoregression (SAR) and geographically weighted regression (GWR) models are used for the spatial data analyses. Similar to ordinary least squares regression (OLSR), regression coefficients are global in SAR model. In other words, the effect of a given independent variable on a dependent variable is valid for the whole country. Unlike OLSR or SAR, GWR reveals the local impact of a given factor (or independent variable) on the waste generation rates of different provinces. Results show that provinces within closer neighborhoods have similar MSW generation rates. On the other hand, this spatial autocorrelation is not very high for the exploratory variables considered in the study. OLSR and SAR models have similar regression coefficients. GWR is useful to indicate the local determinants of MSW generation rates. GWR model can be utilized to plan waste management activities at local scale including waste minimization, collection, treatment, and disposal. At global scale, the MSW generation rates in Turkey are significantly related to unemployment rate and asphalt-paved roads ratio. Yet, significances of these variables may diminish at local scale for some provinces. At local scale, different factors may be important in affecting MSW generation rates.

Keser, Saniye [Department of Environmental Engineering, Middle East Technical University, 06800 Ankara (Turkey); Duzgun, Sebnem [Department of Mining Engineering, Middle East Technical University, 06800 Ankara (Turkey); Department of Geodetic and Geographic Information Technologies, Middle East Technical University, 06800 Ankara (Turkey); Aksoy, Aysegul, E-mail: aaksoy@metu.edu.tr [Department of Environmental Engineering, Middle East Technical University, 06800 Ankara (Turkey)

2012-03-15

165

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 ...

166

Using hospitalization for ambulatory care sensitive conditions to measure access to primary health care: an application of spatial structural equation modeling  

Microsoft Academic Search

BACKGROUND: In data commonly used for health services research, a number of relevant variables are unobservable. These include population lifestyle and socio-economic status, physician practice behaviors, population tendency to use health care resources, and disease prevalence. These variables may be considered latent constructs of many observed variables. Using health care data from South Carolina, we show an application of spatial

James N Laditka

2009-01-01

167

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)

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.

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

2008-12-01

168

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

PubMed

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

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

2014-11-29

169

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

SciTech Connect

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.

De Sapio, Vincent

2010-09-01

170

A spatially-explicit approach for estimating carrying capacity: An application for the Atlantic menhaden ( Brevoortia tyrannus ) in Chesapeake Bay  

Microsoft Academic Search

A spatially-explicit methodology was developed for estimating system carrying capacities of fish stocks, and used to estimate\\u000a the seasonal and spatial patterns of carrying capacity of Chesapeake Bay for Atlantic menhaden (Brevoortia tyrannus). We used a spatially-explicit three-dimensional (3-D) model that divided the heterogeneous habitat of Chesapeake Bay into\\u000a over 4,000 cubes. Each cube represented a volume of water that

Jiangang Luo; Kyle J. Hartman; Stephen B. Brandt; Carl F. Cerco; Thomas H. Rippetoe

2001-01-01

171

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

ERIC Educational Resources Information Center

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…

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

2014-01-01

172

How Students Solve Problems in Spatial Geometry while Using a Software Application for Visualizing 3D Geometric Objects  

ERIC Educational Resources Information Center

In schools, learning spatial geometry is usually dependent upon a student's ability to visualize three dimensional geometric configurations from two dimensional drawings. Such a process, however, often creates visual obstacles which are unique to spatial geometry. Useful software programs which realistically depict three dimensional geometric…

Widder, Mirela; Gorsky, Paul

2013-01-01

173

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

Microsoft Academic Search

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

J. Hill; C. Diemer

1999-01-01

174

Developing an entropy-based model of spatial information estimation and its application in the design of precipitation gauge networks  

NASA Astrophysics Data System (ADS)

This study proposed a spatial information estimation model for the analysis of precipitation gauge networks, to improve on previous methods based on information theory. The proposed model employs a two-dimensional transinformation-distance (T-D) relationship in conjunction with multivariate information approximation to estimate transinformation to ungauged locations from existing stations, while taking into consideration the influence of multiple stations and anisotropy. The proposed model is used to evaluate the spatial distribution of precipitation data and the characteristics of information transfer, which are then applied in a spatial optimization algorithm for the selection of additional station locations. This framework was implemented to investigate temporal and spatial patterns in information content in the Shihmen Reservoir watershed. The results demonstrate obvious anisotropy associated with the delivery of information. By comparing different cases, it was determined that the efficiency of information delivery dominates the spatial distribution of the information content, such that eccentricity is merely supplemental. Efficiency in information delivery is also heavily influenced by temporal scale. For data covering long intervals (monthly and annual), efficiency in the delivery of information is relatively high, while the uncertainty or heterogeneity of hourly or daily time series produces low spatial correlations due to the inefficient delivery of information. The proposed spatial optimization algorithm confirmed that the optimal location for new stations lies close to the center of low information zones. Additional stations could improve information content considerably; however, the margin of improvement decreases with the number of stations.

Su, Ho-Ting; You, Gene Jiing-Yun

2014-11-01

175

The spatial Probit model-An application to the study of banking crises at the end of the 1990’s  

NASA Astrophysics Data System (ADS)

We use a spatial Probit model to study the effect of contagion between banking systems of different countries. Applied to the late 1990s banking crisis in Asia we show that the phenomena of contagion is better seized using a spatial than a traditional Probit model. Unlike the latter, the spatial Probit model allows one to consider the cascade of cross and feedback effects of contagion that result from the outbreak of one initial crisis in one country or system. These contagion effects may result either from business connections between institutions of different countries or from institutional similarities between banking systems.

Amaral, Andrea; Abreu, Margarida; Mendes, Victor

2014-12-01

176

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

E-print Network

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

Fortin, Marie Josee

177

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

E-print Network

Water quality models are applied to assess the various processes affecting the concentrations of contaminants in a watershed. SPAtially Referenced Regression On Watershed attributes (SPARROW) is a nonlinear regression based approach to predict...

, Deepti

2009-05-15

178

Detection of multimode spatial correlation in PDC and application to the absolute calibration of a CCD camera  

E-print Network

We propose and demonstrate experimentally a new method based on the spatial entanglement for the absolute calibration of analog detector. The idea consists on measuring the sub-shot-noise intensity correlation between two branches of parametric down conversion, containing many pairwise correlated spatial modes. We calibrate a scientific CCD camera and a preliminary evaluation of the statistical uncertainty indicates the metrological interest of the method.

Giorgio Brida; Ivo Pietro Degiovanni; Marco Genovese; Maria Luisa Rastello; Ivano Ruo-Berchera

2010-05-17

179

An algorithm based on spatial filter for infrared small target detection and its application to an all directional IRST system  

NASA Astrophysics Data System (ADS)

For the small targets detection in single frame infrared image, a spatial filter algorithm based on an adaptive smooth filter and the Robinson Guard spatial filter is proposed in the paper. The algorithm can detect the small targets in the undulant background effectively with little target information loss; it is implemented easily by digital processor ADSP-TS201S with high performance and successfully used in an all directional IRST system. The experiments show the effectiveness of the detection performance.

Luo, Jun-hui; Ji, Hong-bing; Liu, Jin

2007-01-01

180

A new multidimensional population health indicator for policy makers: absolute level, inequality and spatial clustering - an empirical application using global sub-national infant mortality data.  

PubMed

The need for a multidimensional measure of population health that accounts for its distribution remains a central problem to guide the allocation of limited resources. Absolute proxy measures, like the infant mortality rate (IMR), are limited because they ignore inequality and spatial clustering. We propose a novel, three-part, multidimensional mortality indicator that can be used as the first step to differentiate interventions in a region or country. The three-part indicator (MortalityABC index) combines absolute mortality rate, the Theil Index to calculate mortality inequality and the Getis-Ord G statistic to determine the degree of spatial clustering. The analysis utilises global sub-national IMR data to empirically illustrate the proposed indicator. The three-part indicator is mapped globally to display regional/country variation and further highlight its potential application. Developing countries (e.g. in sub-Saharan Africa) display high levels of absolute mortality as well as variable mortality inequality with evidence of spatial clustering within certain sub-national units ("hotspots"). Although greater inequality is observed outside developed regions, high mortality inequality and spatial clustering are common in both developed and developing countries. Significant positive correlation was observed between the degree of spatial clustering and absolute mortality. The proposed multidimensional indicator should prove useful for spatial allocation of healthcare resources within a country, because it can prompt a wide range of policy options and prioritise high-risk areas. The new indicator demonstrates the inadequacy of IMR as a single measure of population health, and it can also be adapted to lower administrative levels within a country and other population health measures. PMID:25545922

Sartorius, Benn K D; Sartorius, Kurt

2014-11-01

181

Spatially resolved emission using a geometry-dependent system function and its application to excitation temperature profile measurement  

NASA Astrophysics Data System (ADS)

As typical emission spectroscopy involves chord integration along the line of sight, a local measurement with high spatial resolution is attempted using simple lens optics in this work. In the experiment, chord integrated optical plasma emission profile was measured by moving a scanning lens located outside the plasma. The measured emission intensities were spatially reconstructed by employing a geometry-dependent system function, and the local (i.e., only from the lens focal point) emission intensities were obtained with all out-focused emissions subtracted. The 34 different Ar I emission lines spatially reconstructed in this way were used to determine excitation temperature ( Texc) of the argon plasma by the Boltzmann plot method. Being different from the plasma driven at 13.56 MHz where a rather uniform profile was obtained, the spatial profile of Texc from the plasma driven at 90 MHz showed a hollow profile, which is similar to that of the electron temperature ( Te) measured by a Langmuir probe. This hollow profile is attributed from the electromagnetic phenomena such as skin effect and standing wave effect. The similar spatial tendency of Texc and Te implies that Texc can be a representative of Te. This is particularly useful for the cases in which conventional Langmuir probe measurements are limited, such as in large size plasmas.

Park, Hoyong; Choe, Wonho; Yoo, S. J.

2010-12-01

182

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

,Northern Belgium 931 Hydrology and Earth System Sciences, 8(5), 931939 (2004) © EGU Analysis of the spatial.heuvelmans@agr.kuleuven.ac.be Abstract Operational applications of a hydrological model often require the prediction of stream flow of a large river basin. Keywords: hydrological model, regionalisation, parameterisation, spatial variability

Boyer, Edmond

183

Applicability of spectral and spatial information from IKONOS-2 imagery in retrieving leaf area index of forests in the urban area of Nanjing, China  

NASA Astrophysics Data System (ADS)

Remote sensing is currently an indispensable tool for retrieving the leaf area index (LAI) of forests. However, the applicability of remote sensing in retrieving LAI of forests in urban areas has not been thoroughly investigated. The ability of spectral and spatial information from IKONOS-2 imagery to retrieve LAI of forests was studied through analyzing the correlations of four commonly used vegetation indices (VIs) and four texture measures (TEXs) with LAI measured at different types of plots in the urban area of Nanjing, China and comparing the ability of models based on these parameters to estimate LAI of forests. The results show that VIs and TEXs calculated from the high-resolution remote sensing data are both applicable in retrieving LAI of forests in urban areas. The relative advantages of VIs and TEXs are related to the density and spatial regularity of forests. TEX exceeds VI for regularly planted low broad-leaf forests with low density owing to the deterioration of the linkage of VIs with canopy LAI caused by strong soil noise. For forests with moderate and high density, VI exceeds TEX in the retrieval of LAI. As to natural broad-leaf forests with high density and spatial complexity, combining VI and TEX can improve the accuracy of the retrieved LAI by 8.9% to 27.0%. VIs and TEXs are exclusive in retrieving LAI due to the intrinsic linkages of these parameters. The atmospherically resistant vegetation index over-perform other VIs in retrieving LAI of forests owing to its ability to constrain atmospheric disturbance on remote sensing data, which is serious and exhibits great spatial variability in the study area.

Gu, Zhujun; Ju, Weimin; Liu, Yibo; Li, Dengqiu; Fan, Weiliang

2012-01-01

184

Improving 3D Spatial Visualization of Stream Channel Morphology: A Geomorphic Application of ArcView 3D Analyst Extension.  

NSDL National Science Digital Library

This laboratory exercise helps student bridge the gap between fieldwork, data collection, visualization, and interpretation of the data. Using a combination of surveying techniques, spreadsheet modeling, and GIS , students further develop their spatial visualization skills and use these skills to predict geomorphic responses.

John Van Hoesen

185

Modeling the Spatial Distribution and Fruiting Pattern of a Key Tree Species in a Neotropical Forest: Methodology and Potential Applications  

Microsoft Academic Search

BackgroundThe movement patterns of wild animals depend crucially on the spatial and temporal availability of resources in their habitat. To date, most attempts to model this relationship were forced to rely on simplified assumptions about the spatiotemporal distribution of food resources. Here we demonstrate how advances in statistics permit the combination of sparse ground sampling with remote sensing imagery to

Damien Caillaud; Margaret C. Crofoot; Samuel V. Scarpino; Patrick A. Jansen; Carol X. Garzon-Lopez; Annemarie J. S. Winkelhagen; Stephanie A. Bohlman; Peter D. Walsh; Brock Fenton

2010-01-01

186

Non-destructive structural homogeneity of MOEMS arrays: applications of a through-transmissive-media interferometer on a digital mirror device-spatial light modulator  

NASA Astrophysics Data System (ADS)

Interrogation tools are the key to a thorough understanding of any technology. Texas Instruments' DLP® Products â€`` Digital Mirror Device is no exception to this rule. We will discuss the application of a non-destructive, through-glass interferometer system toward gaining insight to the degree of structural uniformity of a statistically significant sampling of micro-opto-electromechanical (MOEM) mirrors as used in our product line. In the course of providing this information, instrumentation details such as reliability and reproducibility of measurements obtained on this interferometer will be discussed. Additionally, the importance of this mechanical uniformity to displaying images with this spatial light modulator (SLM) will be discussed as well.

Heine, L. M.; Oden, P. I.

2006-08-01

187

Method and system for spatially variable rate application of agricultural chemicals based on remotely sensed vegetation data  

NASA Technical Reports Server (NTRS)

Remotely sensed spectral image data are used to develop a Vegetation Index file which represents spatial variations of actual crop vigor throughout a field that is under cultivation. The latter information is processed to place it in a format that can be used by farm personnel to correlate and calibrate it with actually observed crop conditions existing at control points within the field. Based on the results, farm personnel formulate a prescription request, which is forwarded via email or FTP to a central processing site, where the prescription is prepared. The latter is returned via email or FTP to on-side farm personnel, who can load it into a controller on a spray rig that directly applies inputs to the field at a spatially variable rate.

Hood, Kenneth Brown (Inventor); Seal, Michael R. (Inventor); Lewis, Mark David (Inventor); Johnson, James William (Inventor)

2007-01-01

188

A Novel Expression of Spatial Correlation by a Random Curved Surface Model and Its Application to LSI Design  

NASA Astrophysics Data System (ADS)

We have proposed a random curved surface model as a new mathematical concept which enables the expression of spatial correlation. The model gives us an appropriate methodology to deal with the systematic components of device variation in an LSI chip. The key idea of the model is the fitting of a polynomial to an array of Gaussian random numbers. The curved surface is expressed by a new extension from the Legendre polynomials to form two-dimensional formulas. The formulas were proven to be suitable to express the spatial correlation with reasonable computational complexity. In this paper, we show that this approach is useful in analyzing characteristics of device variation of actual chips by using experimental data.

Ohkawa, Shin-Ichi; Masuda, Hiroo; Inoue, Yasuaki

189

Enabling multi-disciplinary climate science through the application of GIS and high-resolution spatial data  

NASA Astrophysics Data System (ADS)

Multidisciplinary field studies in climate science require effective methods for communicating data needs across a broad range of spatial and temporal scales. The Next Generation Ecosystem Experiment-Arctic seeks to reduce uncertainty in climate prediction by investigating critical land-atmosphere interactions in terrestrial ecosystems of Alaska. Using high-resolution LiDAR imagery and GIS, we applied geographic visualization principles to synthesize spatial data and facilitate cross-discipline communication for field planning, instrument implementation and model data integration. We hypothesized that providing three-dimensional (3D) representation of arctic landscape features would enhance perception and provide an effective medium to better optimize further field studies and analyses. Results indicate that key landscape features, such as polygonal ground and drained thaw lake basins (DTLB), represented in 3D maps offered superior recognition and differentiation among these features than traditional 2D maps. When overlaying 3D landscape features with high-resolution spatial data, such as WorldView-2 panchromatic imagery, digital elevation models (DEM), remotely derived indexes such as NDVI, or site instrumentation, further recognition and quantification of landscape processes was attained. Conversely, we observed that data inclusion in excess resulted in poor cognition of key features and/or themes. At various scales, 3D visualization proved to be effective at characterizing both large-scale (1:50) site level characteristics (polygon/trough), as well as small-scale (1:500) regional features (high vs. low polygon terrain). We conclude that applying GIS and high-resolution spatial data to create 3D visualizations is highly effective in representing key arctic landscape features across a wide range of scales. When combining multiple data layers (in moderation), these visualizations prove to be a valuable tool for communicating data needs, refining field implementation plans, and facilitating more efficient model data integration.

Altmann, G.; Wilson, C. J.; Gangodagamage, C.; Wullschleger, S. D.

2013-12-01

190

Modeling the spatial pattern of land-use change with GEOMOD2: application and validation for Costa Rica  

Microsoft Academic Search

The objective of this paper is to simulate the location of land-use change, specifically forest disturbance, in Costa Rica over several decades. This paper presents a GIS-based model, GEOMOD2, which quantifies factors associated with land-use, and simulates the spatial pattern of land-use forward and backward in time. GEOMOD2 reads rasterized maps of land-use and other biogeophysical attributes to determine empirically

R. Gil Pontius Jr; Joseph D. Cornell; Charles A. S. Hall

2001-01-01

191

Statistical monitoring of spatial patterns of environmental indices for integrated ecosystem assessment: Application to the Bay of Biscay pelagic zone  

Microsoft Academic Search

Monitoring the environment of fish is a key component of the ecosystem approach to fisheries management. Here, we propose a methodology to statistically monitor time series of maps of environmental indices. These maps were derived from a 37-year hindcast of a coupled physical–biogeochemical model. The space–time variability in the maps was decomposed using empirical orthogonal functions into time-invariant spatial patterns

Mathieu Woillez; Pierre Petitgas; Martin Huret; Caroline Struski; Fabien Léger

2010-01-01

192

Regional Variation in the Severity of Pesticide Exposure Outcomes: Applications of Geographic Information Systems and Spatial Scan Statistics  

PubMed Central

Introduction In a previous study, Geographic Information Systems (GIS) and spatial scan statistics were utilized to assess regional clustering of symptomatic pesticide exposure incidents that were reported to a state Poison Control Center (PCC) during a single year. In the current study, we analyzed five subsequent years of PCC data to test whether there are significant geographic differences in pesticide exposure incidents resulting in serious (moderate, major, and fatal) medical outcomes. Methods A Poison Control Center provided data on unintentional pesticide exposure incidents for the time period 2001?2005. Data were abstracted to identify the geographic location of the caller, the location where the exposure occurred, the exposure route, and the medical outcome. Results The results yielded 273 incidents resulting in moderate (n=261), major effects (n=10), or fatalities (n=2). Analysis of these data using spatial scan statistics resulted in the identification of a geographic area consisting of 2 adjacent counties (one urban, one rural) where statistically significant clustering of serious outcomes was observed. The relative risk of moderate, major, and fatal outcomes was 2.0 in this spatial cluster (p=0.0005). Conclusions Poison Control Center data, GIS, and spatial scan statistics can be effectively utilized to identify clustering of serious incidents involving human exposure to pesticides. These analyses may be useful for public health officials to target preventive interventions. Further investigation is warranted to better understand the potential explanations for geographical clustering, and to assess whether preventive interventions have an impact on reducing pesticide exposure incidents resulting in serious medical outcomes. PMID:19306192

Sudakin, Daniel L.

2009-01-01

193

Modeling the Spatial Distribution and Fruiting Pattern of a Key Tree Species in a Neotropical Forest: Methodology and Potential Applications  

PubMed Central

Background The movement patterns of wild animals depend crucially on the spatial and temporal availability of resources in their habitat. To date, most attempts to model this relationship were forced to rely on simplified assumptions about the spatiotemporal distribution of food resources. Here we demonstrate how advances in statistics permit the combination of sparse ground sampling with remote sensing imagery to generate biological relevant, spatially and temporally explicit distributions of food resources. We illustrate our procedure by creating a detailed simulation model of fruit production patterns for Dipteryx oleifera, a keystone tree species, on Barro Colorado Island (BCI), Panama. Methodology and Principal Findings Aerial photographs providing GPS positions for large, canopy trees, the complete census of a 50-ha and 25-ha area, diameter at breast height data from haphazardly sampled trees and long-term phenology data from six trees were used to fit 1) a point process model of tree spatial distribution and 2) a generalized linear mixed-effect model of temporal variation of fruit production. The fitted parameters from these models are then used to create a stochastic simulation model which incorporates spatio-temporal variations of D. oleifera fruit availability on BCI. Conclusions and Significance We present a framework that can provide a statistical characterization of the habitat that can be included in agent-based models of animal movements. When environmental heterogeneity cannot be exhaustively mapped, this approach can be a powerful alternative. The results of our model on the spatio-temporal variation in D. oleifera fruit availability will be used to understand behavioral and movement patterns of several species on BCI. PMID:21124927

Scarpino, Samuel V.; Jansen, Patrick A.; Garzon-Lopez, Carol X.; Winkelhagen, Annemarie J. S.; Bohlman, Stephanie A.; Walsh, Peter D.

2010-01-01

194

Evaluating uncertainty in predicting spatially variable representative elementary scales in fractured aquifers, with application to Turkey Creek Basin, Colorado  

USGS Publications Warehouse

Computational limitations and sparse field data often mandate use of continuum representation for modeling hydrologic processes in large-scale fractured aquifers. Selecting appropriate element size is of primary importance because continuum approximation is not valid for all scales. The traditional approach is to select elements by identifying a single representative elementary scale (RES) for the region of interest. Recent advances indicate RES may be spatially variable, prompting unanswered questions regarding the ability of sparse data to spatially resolve continuum equivalents in fractured aquifers. We address this uncertainty of estimating RES using two techniques. In one technique we employ data-conditioned realizations generated by sequential Gaussian simulation. For the other we develop a new approach using conditioned random walks and nonparametric bootstrapping (CRWN)- We evaluate the effectiveness of each method under three fracture densities, three data sets, and two groups of RES analysis parameters. In sum, 18 separate RES analyses are evaluated, which indicate RES magnitudes may be reasonably bounded using uncertainty analysis, even for limited data sets and complex fracture structure. In addition, we conduct a field study to estimate RES magnitudes and resulting uncertainty for Turkey Creek Basin, a crystalline fractured rock aquifer located 30 km southwest of Denver, Colorado. Analyses indicate RES does not correlate to rock type or local relief in several instances but is generally lower within incised creek valleys and higher along mountain fronts. Results of this study suggest that (1) CRWN is an effective and computationally efficient method to estimate uncertainty, (2) RES predictions are well constrained using uncertainty analysis, and (3) for aquifers such as Turkey Creek Basin, spatial variability of RES is significant and complex. Copyright 2006 by the American Geophysical Union.

Wellman, T.P.; Poeter, E.P.

2006-01-01

195

Application of finite-element methods to dynamic analysis of flexible spatial and co-planar linkage systems, part 2  

NASA Technical Reports Server (NTRS)

An approach is described to modeling the flexibility effects in spatial mechanisms and manipulator systems. The method is based on finite element representations of the individual links in the system. However, it should be noted that conventional finite element methods and software packages will not handle the highly nonlinear dynamic behavior of these systems which results form their changing geometry. In order to design high-performance lightweight systems and their control systems, good models of their dynamic behavior which include the effects of flexibility are required.

Dubowsky, Steven

1989-01-01

196

A Comparison of the Spatial Linear Model to Nearest Neighbor (k-NN) Methods for Forestry Applications  

PubMed Central

Forest surveys provide critical information for many diverse interests. Data are often collected from samples, and from these samples, maps of resources and estimates of aerial totals or averages are required. In this paper, two approaches for mapping and estimating totals; the spatial linear model (SLM) and k-NN (k-Nearest Neighbor) are compared, theoretically, through simulations, and as applied to real forestry data. While both methods have desirable properties, a review shows that the SLM has prediction optimality properties, and can be quite robust. Simulations of artificial populations and resamplings of real forestry data show that the SLM has smaller empirical root-mean-squared prediction errors (RMSPE) for a wide variety of data types, with generally less bias and better interval coverage than k-NN. These patterns held for both point predictions and for population totals or averages, with the SLM reducing RMSPE from 9% to 67% over some popular k-NN methods, with SLM also more robust to spatially imbalanced sampling. Estimating prediction standard errors remains a problem for k-NN predictors, despite recent attempts using model-based methods. Our conclusions are that the SLM should generally be used rather than k-NN if the goal is accurate mapping or estimation of population totals or averages. PMID:23527110

Ver Hoef, Jay M.; Temesgen, Hailemariam

2013-01-01

197

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

NASA Astrophysics Data System (ADS)

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.

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

2010-01-01

198

Spatial cognition  

NASA Technical Reports Server (NTRS)

Spatial cognition is the ability to reason about geometric relationships in the real (or a metaphorical) world based on one or more internal representations of those relationships. The study of spatial cognition is concerned with the representation of spatial knowledge, and our ability to manipulate these representations to solve spatial problems. Spatial cognition is utilized most critically when direct perceptual cues are absent or impoverished. Examples are provided of how human spatial cognitive abilities impact on three areas of space station operator performance: orientation, path planning, and data base management. A videotape provides demonstrations of relevant phenomena (e.g., the importance of orientation for recognition of complex, configural forms). The presentation is represented by abstract and overhead visuals only.

Kaiser, Mary Kister; Remington, Roger

1988-01-01

199

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

NASA Technical Reports Server (NTRS)

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.

2002-01-01

200

New Developments and Applications of the MP2RAGE Sequence - Focusing the Contrast and High Spatial Resolution R1 Mapping  

PubMed Central

MR structural T1-weighted imaging using high field systems (>3T) is severely hampered by the existing large transmit field inhomogeneities. New sequences have been developed to better cope with such nuisances. In this work we show the potential of a recently proposed sequence, the MP2RAGE, to obtain improved grey white matter contrast with respect to conventional T1-w protocols, allowing for a better visualization of thalamic nuclei and different white matter bundles in the brain stem. Furthermore, the possibility to obtain high spatial resolution (0.65 mm isotropic) R1 maps fully independent of the transmit field inhomogeneities in clinical acceptable time is demonstrated. In this high resolution R1 maps it was possible to clearly observe varying properties of cortical grey matter throughout the cortex and observe different hippocampus fields with variations of intensity that correlate with known myelin concentration variations. PMID:23874936

Marques, José P.; Gruetter, Rolf

2013-01-01

201

Deposition and characterization of thin ferroelectric lead lanthanum zirconate titanate (PLZT) films on sapphire for spatial light modulators applications.  

PubMed

Ferroelectric lead lanthanum zirconate titanate (PLZT) films are deposited on R-plane sapphire using RF triode magnetron sputtering. Perovskite PLZT films with the desired composition (9/65/35) are obtained using compensated deposition techniques around 500 degrees C and postdeposition annealing at 650 degrees C. The deposited films exhibit good optical and electrooptical properties. The room temperature dielectric constant of the films was 1800 at 10 kHz. The refractive index of the films was in the range of 2.2-2.5. The films showed a quadratic electrooptic effect with R=0.6 x10(-16) m(2)/V(2). The development of PLZT on silicon-on-sapphire smart spatial light modulators using these films is also explored. PMID:18267622

Krishnakumar, S; Ozguz, V H; Fan, C; Cozzolino, C; Esener, S C; Lee, S H

1991-01-01

202

Application of multi-scale variography for inferring the spatial variability of the hydraulic conductivity of a sandy aquifer  

NASA Astrophysics Data System (ADS)

In the framework of the disposal of short-lived low- and intermediate-level radioactive waste in a near-surface disposal facility in Dessel (Belgium), extensive characterization of the hydraulic conductivity (K) in the shallow Neogene aquifer has been performed at a regional scale. In the last few years the small-scale heterogeneity has been additionally characterized by outcrop analogue, hydraulic direct push, and borehole core air permeameter studies. The gathered data now include a) more than 350 hydraulic conductivity measurements on samples from 8 cored boreholes, mostly reaching depths of ~50 m and data at 2 m intervals, b) more than 5000 air permeability measurements on the same borehole cores, c) more than 250 cone penetration tests (CPTs) with depths down to 40 m and data at 2 cm intervals, d) over 100 dissipation tests performed during the CPT campaigns, e) 17 direct push injections loggings, 6 hydraulic profiling tool logs, and 6 direct push slug tests, f) several hundreds of air permeability measurements on outcrop analogues of the aquifer sediments, and g) numerous grain size analyses. The current study aims to quantify the heterogeneity of K from the centimetre- to the kilometre-scale and to check the compatibility of the spatial variability revealed by the different datasets. This is achieved through gathering all K values (either direct measurements, calibrated relative K values, or K estimates from secondary data), and the use of variography to quantify spatial variability in terms of two-points geostatistics. The results are discussed, and the main differences between the different data sources are explained. In a final step, different multi-scale variogram models are proposed for capturing the main characteristics of multi-scale variability within the shallow Neogene aquifer in Belgium.

Rogiers, Bart; Vienken, Thomas; Gedeon, Matej; Batelaan, Okke; Mallants, Dirk; Huysmans, Marijke; Dassargues, Alain

2014-05-01

203

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

PubMed

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

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

2013-05-01

204

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

E-print Network

with application to an fMRI study of twins Joonkoo Park a, , Kerby Shedden b , Thad A. Polk a a Department 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

205

Spatial Displays and Spatial Instruments  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

206

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

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

Jun, Ji Hyun

2011-11-30

207

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

208

THE TWO-DIMENSIONAL PROJECTED SPATIAL DISTRIBUTION OF GLOBULAR CLUSTERS. I. METHOD AND APPLICATION TO NGC 4261  

SciTech Connect

We present a new method for the determination of the two-dimensional (2D) projected spatial distribution of globular clusters (GCs) in external galaxies. This method is based on the K-Nearest Neighbor density estimator of Dressler, complemented by Monte-Carlo simulations to establish the statistical significance of the results. We apply this method to NGC 4261, a ''test galaxy'' where significant 2D anisotropy in the GC distribution has been reported. We confirm that the 2D distribution of GC is not azimuthally isotropic. Moreover, we demonstrate that the 2D distribution departures from the average GC radial distribution results in highly significant spiral-like or broken shell features. Overall, the same perturbations are found in ''red'' and ''blue'' GCs, but with some differences. In particular, we observe a central feature, roughly aligned with the minor axis of NGC 4261, composed of red and most luminous GCs. Blue and fainter GCs are more frequent at large radial distances and follow the spiral-like features of the overall density structure. These results suggest a complex merging history for NGC 4261.

D'Abrusco, R.; Fabbiano, G.; Zezas, A.; Mineo, S.; Fragos, T.; Kim, D.-W. [Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Strader, J. [Department of Astronomy, Michigan State University, 567 Wilson Road, East Lansing, MI 48824-2320 (United States); Bonfini, P. [Physics Department and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion, Crete (Greece); Luo, B. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); King, A. [Department of Physics and Astronomy, University of Leicester, Leicester (United Kingdom)

2013-08-20

209

Application of an imputation method for geospatial inventory of forest structural attributes across multiple spatial scales in the Lake States, U.S.A  

NASA Astrophysics Data System (ADS)

Credible spatial information characterizing the structure and site quality of forests is critical to sustainable forest management and planning, especially given the increasing demands and threats to forest products and services. Forest managers and planners are required to evaluate forest conditions over a broad range of scales, contingent on operational or reporting requirements. Traditionally, forest inventory estimates are generated via a design-based approach that involves generalizing sample plot measurements to characterize an unknown population across a larger area of interest. However, field plot measurements are costly and as a consequence spatial coverage is limited. Remote sensing technologies have shown remarkable success in augmenting limited sample plot data to generate stand- and landscape-level spatial predictions of forest inventory attributes. Further enhancement of forest inventory approaches that couple field measurements with cutting edge remotely sensed and geospatial datasets are essential to sustainable forest management. We evaluated a novel Random Forest based k Nearest Neighbors (RF-kNN) imputation approach to couple remote sensing and geospatial data with field inventory collected by different sampling methods to generate forest inventory information across large spatial extents. The forest inventory data collected by the FIA program of US Forest Service was integrated with optical remote sensing and other geospatial datasets to produce biomass distribution maps for a part of the Lake States and species-specific site index maps for the entire Lake State. Targeting small-area application of the state-of-art remote sensing, LiDAR (light detection and ranging) data was integrated with the field data collected by an inexpensive method, called variable plot sampling, in the Ford Forest of Michigan Tech to derive standing volume map in a cost-effective way. The outputs of the RF-kNN imputation were compared with independent validation datasets and extant map products based on different sampling and modeling strategies. The RF-kNN modeling approach was found to be very effective, especially for large-area estimation, and produced results statistically equivalent to the field observations or the estimates derived from secondary data sources. The models are useful to resource managers for operational and strategic purposes.

Deo, Ram K.

210

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

SciTech Connect

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.

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

211

A high resolution spatial and temporal multiple Doppler analysis of a microburst and its application to aircraft flight simulation  

NASA Technical Reports Server (NTRS)

Multiple Doppler radar data collected during the Joint Airport Weather Studies (JAWS) Project is used to synthesize the three-dimensional wind in the region of a microburst. The particular microburst used in this study is the strongest one to date for which three-dimensional winds have been recovered. As a diagnostic tool, a six-DOF numerical aircraft model having characteristics similar to 727 series aircraft is used to investigate jet transport aircraft response to observed microburst winds during simulated approaches and departures. Simple pilot control laws are used to adjust thrust, pitch, roll, and yaw so as to maintain given approach or departure parameters. Generally, when horizontal wind shear along the approach or departure path is 0.01/s or greater, the model is unable to maintain the desired approach path and suffers a significant reduction in climb performance during a go-around or departure. Although the mean wind shear along a path gives a good qualitative measure of the wind shear threat to a jet transport, different paths with similar mean shears can yield markedly different results, as do the same paths through the microburst at different times. These findings are a direct consequence of the fine temporal and spatial scale of microburst winds. During any given modeled aircraft traverse through the region of highest horizontal shear, time variations in the microburst wind field are shown to have an insignificant effect on the modeled flight path. This is because the traverse period is short (30 s) compared to the lifetime of a microburst (300-600 s).

Elmore, K. L.; Mccarthy, J.; Frost, W.; Chang, H. P.

1986-01-01

212

Nova Spatial  

NSDL National Science Digital Library

Nova Spatial is a software firm which has developed GIS software for the Android (TM) mobile device platform. Products include pcMapper Lite and extensions that allow for creation of GIS shape files using just a standard smartphone.

Llc, Nova S.

213

Spatial agraphia.  

PubMed

Twenty-one patients with right hemisphere damage were studied (11 men, 10 women; average age = 41.33; age range 19-65). Subjects were divided into two groups: pre-Rolandic (6) and retro-Rolandic (15) right hemisphere damaged patients. A special writing test was given to each patient. The writing errors observed included literal substitutions, feature omissions and additions, letter omissions and additions, inability to maintain horizontal writing, inappropriate grouping and fragmentation of elements, and changes in handwriting style. Associated disorders included left-hemiparesis, visual field defects, spatial hemi-neglect, constructional apraxia, spatial alexia, and spatial acalculia. It is proposed that spatial agraphia is related to: (1) left hemi-neglect, (2) constructional deficits, (3) general spatial defects, and (4) some motor disautomatization and tendency to perseverate. In cases of right frontal damage, motor-associated deficits (iterations of features and letters) predominated, whereas in cases of posterior right hemisphere damage, spatial defects (inappropriate distribution of written material in the space, grouping of letters belonging to different words, and splitting of words) were more evident. Writing impairments are in general more noticeable in cases of retro-Rolandic damage. PMID:8373568

Ardila, A; Rosselli, M

1993-07-01

214

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

NASA Astrophysics Data System (ADS)

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.

Xia, Yu; Zhu, Xinyan

2006-10-01

215

Novel Solid-State Spatial Light Modulator on Integrated Circuits for High-Speed Applications with Electro-Optic Thin Film  

Microsoft Academic Search

Novel solid-state spatial light modulator (SLM) is developed. An electro-optic spatial ligNovel solid-state spatial light modulator (SLM) is developed. An electro-optic spatial light modulator (EOSLM) has advantages of high-speed operation, solid-state structure and easy integration with silicon LSIs in comparison with liquid crystal displays (LCD) and micro-electro-mechanical system (MEMS) displays. We propose a kind of Fabry-Perot type planer optical pixel

Y. Fujimori; T. Fujii; T. Suzuki; D. Nishinohara; H. Kimura; T. Fuchikami; M. Moriwake; H. Takasu

2007-01-01

216

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

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.

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

2012-01-01

217

An Automated Land Analysis System (ALAS) for applications at a range of spatial scales: Watershed to global  

SciTech Connect

Recent advances in Digital Elevation Model (DEM) data availability and topographic analysis have enabled us to develop an Automated Land Analysis System (ALAS). ALAS is based on a series of codes which determine topographic and hydrologic characteristics at each pixel, watershed, and each large scale cell. The input requirements are a DEM from any location in the world, it`s resolution, and array size. A Motif accessed script reads in these inputs and generates a series of data sets which further describe the watershed properties such as flow directions, hydrologic characteristic probability density functions, etc.). Postscript files and arrays indicating the fme river networks and each subcatchment, as well as numerous other properties, are produced and catalogued. The motivation behind the development of ALAS is a direct response to the conceptualization of convergent scales between hydrologic and atmospheric models as defined by the World Climate Research Programme. The remainder of this paper highlights ALAS components, capabilities, and provides some discussion on its applications.

Miller, N.L.

1995-08-01

218

Hydrological application of the INCA model with varying spatial resolution and nitrogen dynamics in a northern river basin Hydrology and Earth System Sciences, 6(3), 339350 (2002) EGS  

E-print Network

Hydrological application of the INCA model with varying spatial resolution and nitrogen dynamics in a northern river basin 339 Hydrology and Earth System Sciences, 6(3), 339­350 (2002) © EGS Hydrological ), this paper focuses on calibration of the hydrological part of the model and nitrogen (N) dynamics

Boyer, Edmond

219

Planetary Spatial Analyst  

NASA Technical Reports Server (NTRS)

This is a status report for the project entitled Planetary Spatial Analyst (PSA). This report covers activities from the project inception on October 1, 2007 to June 1, 2008. Originally a three year proposal, PSA was awarded funding for one year and required a revised work statement and budget. At the time of this writing the project is well on track both for completion of work as well as budget. The revised project focused on two objectives: build a solid connection with the target community and implement a prototype software application that provides 3D visualization and spatial analysis technologies for that community. Progress has been made for both of these objectives.

Keely, Leslie

2008-01-01

220

SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations  

E-print Network

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

Zacks, Jeffrey M.

221

Spatial networks  

NASA Astrophysics Data System (ADS)

Complex systems are very often organized under the form of networks where nodes and edges are embedded in space. Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, and neural networks, are all examples where space is relevant and where topology alone does not contain all the information. Characterizing and understanding the structure and the evolution of spatial networks is thus crucial for many different fields, ranging from urbanism to epidemiology. An important consequence of space on networks is that there is a cost associated with the length of edges which in turn has dramatic effects on the topological structure of these networks. We will thoroughly explain the current state of our understanding of how the spatial constraints affect the structure and properties of these networks. We will review the most recent empirical observations and the most important models of spatial networks. We will also discuss various processes which take place on these spatial networks, such as phase transitions, random walks, synchronization, navigation, resilience, and disease spread.

Barthélemy, Marc

2011-02-01

222

A model of spatial data interoperability on Oracle Spatial  

NASA Astrophysics Data System (ADS)

It has been acclaimed that the future vision for GIS data sharing might look like this: each of small counties or towns hosts its own online GIS; and each uses software and a data model selected to best meet its own needs. This paper gives a model based on Oracle Spatial, within a local government or enterprise the spatial data is in centralized storage, and with metadata interoperability, which enables the organizations to use the proper tool for the job while eliminating complicated data transfers and duplications throughout the enterprise or different departments. The MapInfo and ArcGIS software have been made to work together under the same oracle spatial database use trigger and storage process. On another hand, with the situation of between the departments or enterprises, a three-tier structure solution is given: spatial data server, application server and application client. The application server is a mediation system, this model uses oracle application server as the mediation system, and through the application server the application client sends WMS or WFS request and get the map server for background application. The three-tier structure model exposes a GIS portal which is an online GIS for external applications. Any client can request the server if it accords with WMS or WFS specification.

Zhao, Qiansheng; Huang, Quanyi; Guo, Jiming; Wen, Renqiang

2009-10-01

223

[Spatial neglect].  

PubMed

Unilateral spatial (hemi-)neglect or (hemi-)inattention are clinical terms used to describe a number of different clinical symptoms which have in common the patient's failure to attend to, respond adequately to, or orient voluntarily to people or objects in the contralesional space. Unilateral spatial neglect is most often observed following brain lesions affecting the right hemisphere, and in particular the right inferior parietal cortex (angular and supramarginal gyrus) and right temporoparietal junction. Importantly, the term hemineglect cannot be meaningfully used if the target behavior is explained by primary sensory or motor deficits only. Typically the patient's deficit is supramodal: patients with hemineglect fail to respond to novel or meaningful stimuli irrespective of whether they are presented in the visual, auditory, and somesthetic (somatosensory) domain. As adequate perception and spatial representation of both the body and the outside world are mandatory for almost all activities of daily living, hemineglect is known to limit the degree of active participation in rehabilitation programs and is thus commonly associated with poor functional recovery and less successful social reintegration. A number of new promising behavioral and pharmacological treatments may help to ameliorate neglect in the future. PMID:15048330

Fink, G R; Heide, W

2004-04-01

224

Thermodynamic Model of Spatial Memory  

NASA Astrophysics Data System (ADS)

We develop and test a thermodynamic model of spatial memory. Our model is an application of statistical thermodynamics to cognitive science. It is related to applications of the statistical mechanics framework in parallel distributed processes research. Our macroscopic model allows us to evaluate an entropy associated with spatial memory tasks. We find that older adults exhibit higher levels of entropy than younger adults. Thurstone's Law of Categorical Judgment, according to which the discriminal processes along the psychological continuum produced by presentations of a single stimulus are normally distributed, is explained by using a Hooke spring model of spatial memory. We have also analyzed a nonlinear modification of the ideal spring model of spatial memory. This work is supported by NIH/NIA grant AG09282-06.

Kaufman, Miron; Allen, P.

1998-03-01

225

A Bayesian nonparametric model for spatially distributed multivariate binary data with application to a multidrug-resistant tuberculosis (MDR-TB) study.  

PubMed

There has been an increasing interest in the analysis of spatially distributed multivariate binary data motivated by a wide range of research problems. Two types of correlations are usually involved: the correlation between the multiple outcomes at one location and the spatial correlation between the locations for one particular outcome. The commonly used regression models only consider one type of correlations while ignoring or modeling inappropriately the other one. To address this limitation, we adopt a Bayesian nonparametric approach to jointly modeling multivariate spatial binary data by integrating both types of correlations. A multivariate probit model is employed to link the binary outcomes to Gaussian latent variables; and Gaussian processes are applied to specify the spatially correlated random effects. We develop an efficient Markov chain Monte Carlo algorithm for the posterior computation. We illustrate the proposed model on simulation studies and a multidrug-resistant tuberculosis case study. PMID:24975716

Kang, Jian; Zhang, Nanhua; Shi, Ran

2014-12-01

226

Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration.  

PubMed

A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO(2)) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO(2)) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO(2) and HHb, total haemoglobin concentration and SO(2). The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of +/-3.8 g l(-1) (+/-58 microM) and +/-4.4 g l(-1) (+/-68 microM) for the HbO(2) and HHb concentrations respectively and +/-4% for SO(2) with an accuracy in the latter in the range -6%-+7%. PMID:17183133

Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

2007-01-01

227

Development of a spatially universal framework for classifying stream assemblages with application to conservation planning for Great Lakes lotic fish communities  

USGS Publications Warehouse

Classifications are typically specific to particular issues or areas, leading to patchworks of subjectively defined spatial units. Stream conservation is hindered by the lack of a universal habitat classification system and would benefit from an independent hydrology-guided spatial framework of units encompassing all aquatic habitats at multiple spatial scales within large regions. We present a system that explicitly separates the spatial framework from any particular classification developed from the framework. The framework was constructed from landscape variables that are hydrologically and biologically relevant, covered all space within the study area, and was nested hierarchically and spatially related at scales ranging from the stream reach to the entire region; classifications may be developed from any subset of the 9 basins, 107 watersheds, 459 subwatersheds, or 10,000s of valley segments or stream reaches. To illustrate the advantages of this approach, we developed a fish-guided classification generated from a framework for the Great Lakes region that produced a mosaic of habitat units which, when aggregated, formed larger patches of more general conditions at progressively broader spatial scales. We identified greater than 1,200 distinct fish habitat types at the valley segment scale, most of which were rare. Comparisons of biodiversity and species assemblages are easily examined at any scale. This system can identify and quantify habitat types, evaluate habitat quality for conservation and/or restoration, and assist managers and policymakers with prioritization of protection and restoration efforts. Similar spatial frameworks and habitat classifications can be developed for any organism in any riverine ecosystem.

McKenna, James E., Jr.; Schaeffer, Jeffrey S.; Stewart, Jana S.; Slattery, Michael T.

2014-01-01

228

Spatial scaling of net primary productivity using subpixel information  

Microsoft Academic Search

Spatial scaling is of particular importance in remote sensing applications to terrestrial ecosystems where spatial heterogeneity is the norm. Surface parameters derived at different resolutions can be considerably different even though they are derived using the same algorithms. This article addresses issues related to spatial scaling of net primary productivity (NPP). The main objective is to develop algorithms for spatial

Anita Simic; Jing M. Chen; Jane Liu; Ferko Csillag

2004-01-01

229

Dissertation High Performance Spatial Query Processing for Large Scale  

E-print Network

in numerous fields, location based services, geo-social networks, and emerging scientific applications to support high performance spatial queries for spatial big data on MapReduce and CPU-GPU hybrid platformsDissertation Defense High Performance Spatial Query Processing for Large Scale Spatial Data

Garibaldi, Skip

230

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

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...

Ri, Yong-Wu; Im, Song-Jin

2014-01-01

231

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

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

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

2014-01-01

232

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

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

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

2014-01-01

233

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Mutual influence of spatial and temporal fluctuations of a randomly modulated light pulse in a nonlinear medium  

NASA Astrophysics Data System (ADS)

An analytic method of decoupling of physical factors is used to investigate the relationship between the temporal and spatial coherence of a randomly modulated light pulse representing a superposition of a signal and noise in a medium with a local nonlinearity. An analysis is made of the factors that influence the transformation of the spatial and temporal characteristics of a diffracted and spreading light pulse in a nonlinear medium. The relationships governing the mutual influence of the signal and noise, resulting in changes in the regular envelopes and statistical characteristics, are determined.

Aleshkevich, Viktor A.; Kozhoridze, G. D.; Matveev, A. N.

1988-04-01

234

Demographic and Spatial Factors as Causes of an Epidemic Spread, the Copule Approach: Application to the Retro-prediction of the Black Death Epidemy of 1346  

Microsoft Academic Search

The classical models by Ross and McKendrick have to be revisited in order to incorporate dynamical elements coming from the demography and from the spatial aspects of epidemics. The classical approach is dealing with populations supposed to be constant during the epidemic wave, but the present pandemics show duration during years imposing now to take into account the population growth

Jean Gaudart; Mohamad Ghassani; Julie Mintsa; Jules Waku; Mustapha Rachdi; Ogobara K. Doumbo; Jacques Demongeot

2010-01-01

235

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

Microsoft Academic Search

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

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

2003-01-01

236

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

PubMed Central

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 (GAMs) and geographical information systems (GIS). Methods We investigated the association between residence and bladder, kidney, and pancreatic cancer on upper Cape Cod. We estimated adjusted odds ratios using GAMs, smoothing on location. A 40-year residential history allowed for latency restrictions. We mapped spatially continuous odds ratios using GIS and identified statistically significant clusters using permutation tests. Results Maps of bladder cancer are essentially flat ignoring latency, but show a statistically significant hot spot near known Massachusetts Military Reservation (MMR) groundwater plumes when 15 years latency is assumed. The kidney cancer map shows significantly increased ORs in the south of the study area and decreased ORs in the north. Conclusion Spatial epidemiology using individual level data from population-based studies addresses many methodological criticisms of cluster studies and generates new exposure hypotheses. Our results provide evidence for spatial clustering of bladder cancer near MMR plumes that suggest further investigation using detailed exposure modeling. PMID:19208254

2009-01-01

237

A spatially explicit model of runoff, evaporation, and lake extent: Application to modern and late Pleistocene lakes in the Great Basin region, western United States  

Microsoft Academic Search

A spatially explicit hydrological model was applied to the Great Basin in the western United States to predict runoff magnitude and lake distributions under modern and late Pleistocene conditions. The model iteratively routes runoff through depression to find a steady state solution and was calibrated with mean annual precipitation, pan evaporation, temperature, and stream runoff data. The predicted lake distribution

Yo Matsubara; Alan D. Howard

2009-01-01

238

Spatial Aspects of Census Districting  

NASA Astrophysics Data System (ADS)

Urban districting refers to partitioning of an urban area into smaller regions for a specific application in order to effectively facilitate and enhance the quality of municipal services. Among other considerations, which are imposed by the general problem or the application in hand, several factors in urban districting have spatial aspects, many of which have been disregarded in most of districting plans, and only descriptive measures have been considered. This paper explores the impact of spatial aspects on census districting, as an important urban districting. It proposes an approach that not only considers the workload, as the most effective criterion in census districting, but spatial criteria such as compactness, barriers and travers length are also involved. The implementation results of the proposed approach for a case study have been evaluated and discussed.

Dezyani, S.; Karimipour, F.

2014-10-01

239

Spatially extended atmospheric plasma arrays  

Microsoft Academic Search

This paper reports a systematic study of spatially extended atmospheric plasma (SEAP) arrays employing many parallel plasma jets packed densely and arranged in an honeycomb configuration. The work is motivated by the challenge of using inherently small atmospheric plasmas to address many large-scale processing applications including plasma medicine. The first part of the study considers a capillary-ring electrode configuration as

Z. Cao; Q. Nie; D. L. Bayliss; J. L. Walsh; C. S. Ren; D. Z. Wang; M. G. Kong

2010-01-01

240

Video Games and Spatial Cognition  

Microsoft Academic Search

Video game enthusiasts spend many hours at play, and this intense activity has the potential to alter both brain and behavior. We review studies that investigate the ability of video games to modify processes in spatial cognition. We outline the initial stages of research into the underlying mechanisms of learning, and we also consider possible applications of this new knowledge.

Ian Spence; Jing Feng

2010-01-01

241

A Rational Probabilistic Method for Spatially Distributed Landslide Hazard Assessment  

E-print Network

A Rational Probabilistic Method for Spatially Distributed Landslide Hazard Assessment WILLIAM C, Landslides, Probabi- listic, Computer Applications, West Virginia ABSTRACT First-order, second-moment (FOSM models to perform spatially distributed probabilistic landslide hazard analyses. This is most easily

Haneberg, William C.

242

Spatial-Operator Algebra For Robotic Manipulators  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

243

Block Kriging for Lognormal Spatial Processes  

Microsoft Academic Search

Lognormal spatial data are common in mining and soil-science applications. Modeling the underlying spatial process as normal\\u000a on the log scale is sensible; point kriging allows the whole region of interest to be mapped. However, mining and precision\\u000a agriculture is carried out selectively and is based on block averages of the process on the original scale. Finding spatial\\u000a predictions of

Noel Cressie

2006-01-01

244

Spatial Thinking Strategies  

NSDL National Science Digital Library

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,

Susan Everett

2000-04-01

245

Experimental demonstration of an intensity minimum at the focus of a laser beam created by spatial coherence: application to the optical trapping of dielectric particles.  

PubMed

In trying to manipulate the intensity distribution of a focused field, one typically uses amplitude or phase masks. Here we explore an approach, namely, varying the state of spatial coherence of the incident field. We experimentally demonstrate that the focusing of a Bessel-correlated beam produces an intensity minimum at the geometric focus rather than a maximum. By varying the spatial coherence width of the field, which can be achieved by merely changing the size of an iris, it is possible to change this minimum into a maximum in a continuous manner. This method can be used, for example, in novel optical trapping schemes, to selectively manipulate particles with either a low or high index of refraction. PMID:21165125

Raghunathan, Shreyas B; van Dijk, Thomas; Peterman, Erwin J G; Visser, Taco D

2010-12-15

246

Equilibrium relations and bipolar cognitive mapping for online analytical processing with applications in international relations and strategic decision support  

Microsoft Academic Search

Bipolar logic, bipolar sets, and equilibrium relations are proposed for bipolar cognitive mapping and visualization in online analytical processing (OLAP) and online analytical mining (OLAM). As cognitive models, cognitive maps (CMs) hold great potential for clustering and visualization. Due to the lack of a formal mathematical basis, however, CM-based OLAP and OLAM have not gained popularity. Compared with existing approaches,

Wen-ran Zhang

2003-01-01

247

CCS scenarios optimisation by spatial multi-criteria analysis: Application to multiple source-sink matching in the Bohai Basin (North China)  

Microsoft Academic Search

Methods, based on spatial analysis of the different criteria to be taken into consideration for building scenarios of CO2 Capture and Storage (CCS), have been developed and applied to real case studies in the Hebei Province (northeast China). The total CO2 emissions from point sources in the province amount to 220Mt\\/y, mainly from power plants, and from iron-steel, cement, ammonia

Wenying Chen; Fei Teng; Ruina Xu; Xing Xiang; Rongshu Zeng; Kim Domptail; Delphine Allier; Yves-Michel Le Nindrec

2009-01-01

248

Measuring boundary convexity at multiple spatial scales using a linear “moving window” analysis: an application to coastal river otter habitat selection  

Microsoft Academic Search

Landscape metrics have been used to quantify ecological patterns and to evaluate relationships between animal presence\\/abundance\\u000a and habitat at multiple spatial scales. However, many ecological flows occur in linear systems such as streams, or across\\u000a patch\\/landscape boundaries (ecotones). Some organisms and flows may depend on the boundary shape, but metrics for defining\\u000a linear boundary characteristics are scarce. While sinuosity and

Shannon E. AlbekeNathan; Nathan P. Nibbelink; Lan Mu; Daniel J. Ellsworth

2010-01-01

249

Application of spatial database in quantitative analysis of litho-paleogeography—A case study of a middle ordovician sequence interval in the Ordos Basin  

Microsoft Academic Search

In the study of sequence stratigraphy and litho-paleogeography, quantitative analysis, precise calculation and detailed comparison\\u000a of tremendous geological data, such as field profiles, logging records and seismic curves from different areas, are the basic\\u000a requirements. In order to obtain a more reliable and precise result, this paper presents a novel method that combines spatial\\u000a database analysis with the single-factor mapping

Bin Li; Feiyan Liao; Hao Meng; Yanchun Zhong

2011-01-01

250

GIS and spatial data analysis: Converging perspectives  

Microsoft Academic Search

This article identifies some of the important developments in GIS and spatial data analysis since the early 1950s. Although GIS and spatial data analysis started out as two more or less separate areas of research and application, they have grown closer together over time. We argue that the two areas meet in the field of geographic information science, with each

Michael F. Goodchild; Robert P. Haining

2003-01-01

251

Spatial analysis of soybean canopy response to soybean cyst nematodes (Heterodera glycines) in eastern Arkansas: An approach to future precision agriculture technology application  

NASA Astrophysics Data System (ADS)

Heterodera glycines Ichinohe, commonly known as soybean cyst nematode (SCN) is a serious widespread pathogen of soybean in the US. Present research primarily investigated feasibility of detecting SCN infestation in the field using aerial images and ground level spectrometric sensing. Non-spatial and spatial linear regression analyses were performed to correlate SCN population densities with Normalized Difference Vegetation Index (NDVI) and Green NDVI (GNDVI) derived from soybean canopy spectra. Field data were obtained from two fields; Field A and B under different nematode control strategies in 2003 and 2004. Analysis of aerial image data from July 18, 2004 from the Field A showed a significant relationship between SCN population at planting and the GNDVI (R2=0.17 at p=0.0006). Linear regression analysis revealed that SCN had a little effect on yield (R2 =0.14, at p=0.0001, RMSEP=1052.42 kg ha-1) and GNDVI (R 2=0.17 at p=0.0006, RMSEP=0.087) derived from the aerial imagery on a single date. However, the spatial regression analysis based on spherical semivariogram showed that the RMSEP was 0.037 for the GNDVI on July 18, 2004 and 427.32 kg ha-1 for yield on October 14, 2003 indicating better model performance. For July 18, 2004 data from Field B, a relationship between NDVI and the cyst counts at planting was significant (R2=0.5 at p=0.0468). Non-spatial analyses of the ground level spectrometric data for the first field showed that NDVI and GNDVI were correlated with cyst counts at planting (R 2=0.34 and 0.27 at p=0.0015 and 0.0127, respectively), and GNDVI was correlated with eggs count at planting (R2= 0.27 at p=0.0118). Both NDVI and GNDVI were correlated with egg counts at flowering (R 2=0.34 and 0.27 at p=0.0013 and 0.0018, respectively). However, paired T test to validate the above relationships showed that, predicted values of NDVI and GNDVI were significantly different. The statistical evidences suggested that variability in vegetation indices was caused by SCN infestation. Comparison of estimators such as -2 RLL, AIC, and BIC of non-spatial and spatial models affirmed that incorporating spatial covariance structure of observations improved model performances. These results demonstrated a limited potential of aerial imaging and ground level spectrometry for detecting nematode infestation in the field. However, it is strongly recommended that more multisite-multiyear trials must be performed to establish and validate empirical models to quantify SCN population densities and their impact on soybean canopy reflectance.

Kulkarni, Subodh

2008-10-01

252

Approximate spatial reasoning  

NASA Technical Reports Server (NTRS)

A model for approximate spatial reasoning using fuzzy logic to represent the uncertainty in the environment is presented. Algorithms are developed which can be used to reason about spatial information expressed in the form of approximate linguistic descriptions similar to the kind of spatial information processed by humans. Particular attention is given to static spatial reasoning.

Dutta, Soumitra

1988-01-01

253

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

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

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

2014-07-01

254

Spatial representation of soundscape  

NASA Astrophysics Data System (ADS)

For the last 30 years the concept of soundscape has been largely adopted in many scientific disciplines and by the urban experts for the benefit of a better comprehension and management of the sound environment. However, the spatial representation of the soundscape as a simple tool for the description, management or composition of sound environment is always needed. In this article a method is presented for the spatial sound representation with differentiated sources. The first results are shown. This method gives an account of the soundscape as close as possible to the way it can be perceived by the listener in each location. This method generates qualitative sound maps in a reduced urban scale, based on in situ measurements and on the implication of the measuring subject perception. The maps are sufficient enough to isolate many sound sources of the overall sound field. In this manner, sound quality refers to the sound attribute of a perceived object. It is neither an aesthetic judgment nor traditional psychoacoustics criteria. Concrete examples of application to squares in the city of Lisbon will be shown and discussed. The limits and the prospects of such a qualitative representation will also be presented and discussed.

Boubezari, Mohammed; Bento Coelho, Jos-Luis

2001-05-01

255

TeachSpatial Annotations  

NSDL National Science Digital Library

The TeachSpatial collection assembles digital teaching resources relevant to spatial cognition, spatial learning, and spatial literacy across multiple STEM disciplines for middle school, high school, and undergraduate learners. Common topics include physical geography, GIS (Geographic Information Systems), and map reading skills (population demographics, geographic coordinates, etc.). Resources are indexed by the core spatial concepts and principles found in the 1996 National Science Education Standards and contain comments and ratings from a community of users. TeachSpatial is a project of the Center for Spatial Studies at the University of California, Santa Barbara.

2012-01-17

256

SpatialNews  

NSDL National Science Digital Library

The applications of geographic information systems (GIS) grow with each passing day, and more people are interested in careers in this field. The SpatialNews site is a good way for students and professionals in the GIS field to stay on top of new developments via their feature articles, RSS feeds, and discussion boards. There is a great deal of information on the homepage, and first-time visitors should start by looking over the sections on "GIS Education", "Features", and "Business Bit & Bytes". Some of the more notable feature articles profile the history of GIS, the use of GIS in the military, and the use of GIS during hurricane evacuations. The site is rounded out by a listing of job opportunities and selected comments from the discussion boards.

257

Spatial Standard Observer  

NASA Technical Reports Server (NTRS)

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.

Watson, Andrw B. (Inventor)

2010-01-01

258

Spatial Standard Observer  

NASA Technical Reports Server (NTRS)

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.

Watson, Andrew B. (Inventor)

2012-01-01

259

[Bayesian statistics in spatial epidemiology].  

PubMed

Through the multi-stage hierarchical Bayesian model and Markov Chain Monte Carlo methods, Bayesian statistics can be used in dependent spatial data analysis, including disease mapping in small areas, disease clustering, and geographical correlation studies. Recently, Bayesian spatial models have been developed with many types, which have made considerable progress in data analysis. This paper introduces several approaches that have been fully developed and applied, such as BYM model,joint model, semi-parameter model, moving average model and so on. Recently,many studies focused on the comparison work through Deviance Information criterion. Those results show that BYM model and MIX model of semi-parameter model could obtain better results. As more research going on, Bayesian statistics will have more space in applications of spatial epidemiology. PMID:19084965

Zheng, Wei-jun; Li, Xiu-yang; Chen, Kun

2008-11-01

260

Center for Advanced Spatial Technologies  

NSDL National Science Digital Library

The Center for Advanced Spatial Technologies (CAST) at the University of Arkansas is dedicated to applications in Geographic Information Systems (GIS), remote sensing, digital photogrammetry and interoperability, and Global Positioning Systems (GPS). This enormous site contains a wide range of research activities in spatial technologies as applied to the disciplines of environmental studies, archaeology, historical preservation, landscape architecture, urban and rural planning, spatial statistics, and data development. Within the Reports and Publications section, the Arkansas Gap Analysis Program (GAP) final report is available (in HTML and .pdf formats) and, though the work itself was completed in 1998, the report provides excellent information on biodiversity assessment and land-cover mapping (For the national Gap Analysis Program Website, see the September 17, 1997 Scout Report for Science & Engineering). Each of the research areas of the site contains documentation of projects and links to related sites.

2005-12-07

261

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)

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.

Mendoza Lebrun, Daniel

262

Application of spatially distributed coupled glacio-hydrological model to predict the effect of glacier recession on the flow of the Upper Bow River, Alberta, Canada  

NASA Astrophysics Data System (ADS)

Several recent studies have suggested that observed decreases in summer flows in Canada's South Saskatchewan River are partly due to retreat of glaciers in the river's headwaters. Despite the risk posed by declining glaciers to water supply in the high mountain river systems, our ability to accurately predict runoff contribution from partially glacierized basins is limited. Modeling the effect of glacier changes on streamflow response in such basins is complicated due to limited availability of high resolution gridded meteorological data, lack of long term measurements of glaciological parameters and most importantly glacier dynamics are not linked to hydrological processes in many existing physically-based distributed hydrologic models. We investigate the effect of glacier recession on streamflow variations for the Upper Bow River basin, a tributary of the South Saskatchewan, near Lake Louise, Alberta, using the Distributed Hydrology Soil Vegetation Model (DHSVM) coupled with the spatially distributed glacier dynamics model. The coupled model is forced with the North American Regional Reanalysis (NARR) climate data for the period of 1979 - 2010 at a 3-hourly time step. The NARR data are adjusted for spatial variability in precipitation and temperature using the Parameter-elevation Regressions on Independent Slopes Model (PRISM) monthly data at 2.5 arcmin resolution made available through the Climate Western North America (ClimateWNA) database (Wang et al. 2006). Using known subglacial bed topography information, a multidecade spin-up run of the stand alone glacier model is first conducted until the beginning of the simulation period for the coupled model to accurately predict ice thickness confirmed through comparison of modeled ice margins with observed glacier extent. The integrated model initialized with already estimated glacier thickness and ice extent is then run to predict glacier evolution, including spatial extent in combination with other hydrologic processes such as glacier/snow melt, surface runoff, baseflow and evapotranspiration. We test the coupled glacio-hydrologic model performance through comparison of predicted variations in glacier extent, snow water equivalent and streamflow discharge with satellite estimates of glacier area and terminus position combined with stream discharge and observed snow data. Our initial results show the effects on the hydrology of the Bow River as related to retreat of the glacier and its replacement with seasonal snow cover, and the differences in melt and runoff generation associated with this transition.

Naz, B. S.; Frans, C. D.; Clarke, G. K.; Nolin, A. W.; Lettenmaier, D. P.; Istanbulluoglu, E.; Burns, P. J.

2011-12-01

263

Spatial and temporal heterogeneity explain disease dynamics in a spatially explicit network model.  

PubMed

There is an increasing recognition that individual-level spatial and temporal heterogeneity may play an important role in metapopulation dynamics and persistence. In particular, the patterns of contact within and between aggregates (e.g., demes) at different spatial and temporal scales may reveal important mechanisms governing metapopulation dynamics. Using 7 years of data on the interaction between the anther smut fungus (Microbotryum violaceum) and fire pink (Silene virginica), we show how the application of spatially explicit and implicit network models can be used to make accurate predictions of infection dynamics in spatially structured populations. Explicit consideration of both spatial and temporal organization reveals the role of each in spreading risk for both the host and the pathogen. This work suggests that the application of spatially explicit network models can yield important insights into how heterogeneous structure can promote the persistence of species in natural landscapes. PMID:18662121

Brooks, Christopher P; Antonovics, Janis; Keitt, Timothy H

2008-08-01

264

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

PubMed

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

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

2003-10-01

265

New developments and applications of the MP2RAGE sequence--focusing the contrast and high spatial resolution R1 mapping.  

PubMed

MR structural T1-weighted imaging using high field systems (>3T) is severely hampered by the existing large transmit field inhomogeneities. New sequences have been developed to better cope with such nuisances. In this work we show the potential of a recently proposed sequence, the MP2RAGE, to obtain improved grey white matter contrast with respect to conventional T1-w protocols, allowing for a better visualization of thalamic nuclei and different white matter bundles in the brain stem. Furthermore, the possibility to obtain high spatial resolution (0.65 mm isotropic) R1 maps fully independent of the transmit field inhomogeneities in clinical acceptable time is demonstrated. In this high resolution R1 maps it was possible to clearly observe varying properties of cortical grey matter throughout the cortex and observe different hippocampus fields with variations of intensity that correlate with known myelin concentration variations. PMID:23874936

Marques, José P; Gruetter, Rolf

2013-01-01

266

Automated three-dimensional detection and classification of living organisms using digital holographic microscopy with partial spatial coherent source: application to the monitoring of drinking water resources.  

PubMed

In this paper, we investigate the use of a digital holographic microscope working with partially coherent spatial illumination for an automated detection and classification of living organisms. A robust automatic method based on the computation of propagating matrices is proposed to detect the 3D position of organisms. We apply this procedure to the evaluation of drinking water resources by developing a classification process to identify parasitic protozoan Giardia lamblia cysts among two other similar organisms. By selecting textural features from the quantitative optical phase instead of morphological ones, a robust classifier is built to propose a new method for the unambiguous detection of Giardia lamblia cyst that present a critical contamination risk. PMID:23292424

El Mallahi, Ahmed; Minetti, Christophe; Dubois, Frank

2013-01-01

267

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

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

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

2014-11-01

268

SCALABLE PARALLEL APPROXIMATE FORMULATIONS OF MULTI DIMENSIONAL SPATIAL AUTOREGRESSION MODELS FOR SPATIAL DATA MINING 1  

Microsoft Academic Search

The spatial auto-regression (SAR) model is a popula r spatial data analysis technique which has been used in many applications with geo-spatial datasets. Howeve r, exact solutions for estimating SAR parameters are computationally expensive due to the need to compute all the eigen-values of a very large matrix . Therefore, serial solutions for the SAR model do not scale up

Shashi Shekhar; Baris M. Kazar; David J. Lilja

269

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

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

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

2014-06-01

270

Spatial Solitons in Algaas Waveguides  

NASA Astrophysics Data System (ADS)

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.

Kang, Jin Ung

271

Tempo-spatially resolved scattering correlation spectroscopy under dark-field illumination and its application to investigate dynamic behaviors of gold nanoparticles in live cells.  

PubMed

In this study, a new tempo-spatially resolved fluctuation spectroscopy under dark-field illumination is described, named dark-field illumination-based scattering correlation spectroscopy (DFSCS). DFSCS is a single-particle method, whose principle is similar to that of fluorescence correlation spectroscopy (FCS). DFSCS correlates the fluctuations of the scattered light from single nanoparticle under dark-field illumination. We developed a theoretical model for translational diffusion of nanoparticles in DFSCS system. The results of computer simulations documented that this model was able to well describe the diffusion behaviors of nanoparticles in uniformly illuminated field. The experimental setup of DFSCS was achieved by introducing a dark-field condenser to the frequently used bright-field microscope and an electron multiplying charge-coupled device (EMCCD) as the array detector. In the optimal condition, a stack of 500?000 frames were collected simultaneously on 64 detection channels for a single measurement with acquisition rate of 0.5 ms per frame. We systematically investigated the effect of certain factors such as particle concentration, viscosity of the solution, and heterogeneity of gold nanoparticles (GNPs) samples on DFSCS measurements. The experiment data confirmed theoretical model proposed. Furthermore, this new method was successfully used for investigating dynamic behaviors of GNPs in live cells. Our preliminary results demonstrate that DFSCS is a practical and affordable tool for ordinary laboratories to investigate the dynamic information of nanoparticles in vitro as well as in vivo. PMID:24460214

Liu, Heng; Dong, Chaoqing; Ren, Jicun

2014-02-19

272

A Software Tool to Model Genetic Regulatory Networks. Applications to the Modeling of Threshold Phenomena and of Spatial Patterning in Drosophila  

PubMed Central

We present a general methodology in order to build mathematical models of genetic regulatory networks. This approach is based on the mass action law and on the Jacob and Monod operon model. The mathematical models are built symbolically by the Mathematica software package GeneticNetworks. This package accepts as input the interaction graphs of the transcriptional activators and repressors of a biological process and, as output, gives the mathematical model in the form of a system of ordinary differential equations. All the relevant biological parameters are chosen automatically by the software. Within this framework, we show that concentration dependent threshold effects in biology emerge from the catalytic properties of genes and its associated conservation laws. We apply this methodology to the segment patterning in Drosophila early development and we calibrate the genetic transcriptional network responsible for the patterning of the gap gene proteins Hunchback and Knirps, along the antero-posterior axis of the Drosophila embryo. In this approach, the zygotically produced proteins Hunchback and Knirps do not diffuse along the antero-posterior axis of the embryo of Drosophila, developing a spatial pattern due to concentration dependent thresholds. This shows that patterning at the gap genes stage can be explained by the concentration gradients along the embryo of the transcriptional regulators. PMID:20523731

Dilão, Rui; Muraro, Daniele

2010-01-01

273

Multiband Multislice GE-EPI at 7 Tesla, With 16-Fold Acceleration Using Partial Parallel Imaging With Application to High Spatial and Temporal Whole-Brain FMRI  

PubMed Central

Parallel imaging in the form of multiband radiofrequency excitation, together with reduced k-space coverage in the phase-encode direction, was applied to human gradient echo functional MRI at 7 T for increased volumetric coverage and concurrent high spatial and temporal resolution. Echo planar imaging with simultaneous acquisition of four coronal slices separated by 44mm and simultaneous 4-fold phase-encoding undersampling, resulting in 16-fold acceleration and up to 16-fold maximal aliasing, was investigated. Task/stimulus-induced signal changes and temporal signal behavior under basal conditions were comparable for multiband and standard single-band excitation and longer pulse repetition times. Robust, whole-brain functional mapping at 7 T, with 2 × 2 × 2mm3 (pulse repetition time 1.25 sec) and 1 × 1 × 2mm3 (pulse repetition time 1.5 sec) resolutions, covering fields of view of 256 × 256 × 176mm3 and 192 × 172 × 176mm3, respectively, was demonstrated with current gradient performance. PMID:20432285

Moeller, Steen; Yacoub, Essa; Olman, Cheryl A.; Auerbach, Edward; Strupp, John; Harel, Noam; U?urbil, Kâmil

2010-01-01

274

An application of remotely derived climatological fields for risk assessment of vector-borne diseases : a spatial study of filariasis prevalence in the Nile Delta, Egypt.  

SciTech Connect

This paper applies a relatively straightforward remote sensing method that is commonly used to derive climatological variables. Measurements of surface reflectance and surface radiant temperature derived from Landsat Thematic Mapper data were used to create maps of fractional vegetation and surface soil moisture availability for the southern Nile delta in Egypt. These climatological variables were subsequently used to investigate the spatial distribution of the vector borne disease Bancroftian filariasis in the Nile delta where it is focally endemic and a growing problem. Averaged surface soil moisture values, computed for a 5-km border area around affected villages, were compared to filariasis prevalence rates. Prevalence rates were found to be negligible below a critical soil moisture value of 0.2, presumably because of a lack of appropriate breeding sites for the Culex Pipiens mosquito species. With appropriate modifications to account for local conditions and vector species, this approach should be useful as a means to map, predict, and control insect vector-borne diseases that critically depend on wet areas for propagation. This type of analysis may help governments and health agencies that are involved in filariasis control to better focus limited resources to identifiable high-risk areas.

Crombie, M. K.; Gillies, R. R.; Arvidson, R. E.; Brookmeyer, P.; Weil, G. J.; Sultan, M.; Harb, M.; Environmental Research; Washington Univ.; Utah State Univ.; Egyptian Ministry of Health

1999-12-01

275

Comparing the applicability of some geostatistical methods to predict the spatial distribution of topsoil Calcium Carbonate in part of farmland of Zanjan Province  

NASA Astrophysics Data System (ADS)

Most of soils in iran, were located in the arid and semi-arid regions and have high pH (more than 7) and high amount of calcium carbonate and this problem cause to their calcification.In calcareous soils, plant growing and production is difficult. Most part of this problem, in relation to high pH and high concentration of calcium ion that cause to fixation and unavailability of elements which were dependent to pH, especially Phosphorous and some micro nutrients such as Fe, Zn, Mn and Cu. Prediction of soil calcium carbonate in non-sampled areas and mapping the calcium carbonate variability in order to sustainable management of soil fertility is very important.So, this research was done with the aim of evaluation and analyzing spatial variability of topsoil calcium carbonate as an aspect of soil fertility and plant nutrition, comparing geostatistical methods such as kriging and co-kriging and mapping topsoil calcium carbonate. For geostatistical analyzing, sampling was done with stratified random method and soil samples from 0 to 15 cm depth were collected with auger within 23 locations.In co-kriging method, salinity data was used as auxiliary variable. For comparing and evaluation of geostatistical methods, cross validation were used by statistical parameters of RMSE. The results showed that co-kriging method has the highest correlation coefficient and less RMSE and has the higher accuracy than kriging method to prediction of calcium carbonate content in non-sampled areas.

Sarmadian, Fereydoon; Keshavarzi, Ali

2010-05-01

276

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

PubMed

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

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

2014-09-01

277

Application of a two-dimensional model to describe the CO2 exchange between a spatially non-uniform forest stand and the atmosphere  

NASA Astrophysics Data System (ADS)

Within the framework of the study a two dimensional hydrodynamic high-resolution model of the energy, H2O, CO2 turbulent exchange was developed and applied to describe effect of the horizontal and vertical heterogeneity of a forest canopy on CO2exchange between soil surface, forest stand and the atmosphere under different weather conditions. Most attention in the study was paid to analyze the influence of forest clearing, windthrow of different sizes, forest edges, etc. on turbulent exchange rate and CO2 flux partitioning between forest overstorey, understorey and soil surface. The modeling experiments were provided under different wind conditions, thermal stratification of the atmospheric boundary layer, incoming solar radiation, etc. To quantify effect of spatial heterogeneity on total ecosystem fluxes the modeling results were compared with CO2 fluxes modeled for a spatially uniform forest canopy under similar ambient conditions. The averaged system of hydrodynamic equations is used for calculating the components of the mean velocity ?V = {V1, V2}: ( ( ) ) ?Vi+ V ?Vi= - 1-??P- - -?- ? E - K ?Vi-+ ?Vj- + F, ?Vi = 0, ?t j?xj ?0 ?xi ?xj ij ?xj ?xi i ?xi where E is the turbulent kinetic energy (TKE), K is the turbulent diffusivity, ?P is the deviation of pressure from the hydrostatic distribution and ?0?F is the averaged force of air flow interaction with vegetation. F? was parameterized as ?F = -cd ·LAD ·| | ||V?||·?V, where cd is the drag coefficient and LAD is the leaf area density. The turbulent diffusivity K can be expressed by means of TKE and the velocity of TKE dissipation ? as follows: K = C?E2?-1, where C? is the proportionality coefficient. One of the ways to obtain E and ? is to solve the additional system of two differential equations of diffusion-transport type: ( ) ( ) ?E- -?E- -?- -K-?E- ?-? ??- -?- K-?? -? ( 1 2 ) ?t +Vj?xj = ?xi ?E ?xi +PE - ?, ?t +Vj ?xj = ?xi ???xi +E C ?PE - C?? - ? ?, where ?E and ?? are the Prandtl numbers, PE is the TKE production by shear, C?1 and C?2 are the model constants. The term ?? = ?- E(C ?1 - C?2) · 12C?1/2c dLAD||? || |V |E describes the increase of TKE dissipation due to the interaction with vegetation elements. The function ? can be any of the following variables: ?, ?/ E, or El, where l is the mixing length. Detailed analysis of these equations performed by Sogachev (Sogachev, Panferov, 2006) showed that for ? = ?/ E the model is less sensible to the errors of the input data. Transfer equation for CO2 within and above a plant canopy can be written as: ( ) ?C- -?C- -?- -K-?C- ?t + Vj?xj = ?xi ?C ?xi + FC, where C is CO2 concentration, ?C is the Prandtl number, and the term FC describes the sources/sinks of CO2 in the vegetation and soil. For parameterization of the photosynthesis rate in the forest canopy the Monsi and Saeki approach (Monsi M., Saeki T., 1953) was applied. Stem respiration was ignored in the study. The CO2 emission from the soil surface into the atmosphere was assumed to be constant for entire forest area. This study was supported by grants of the Russian Foundation for Basic Research (RFBR 14-04-01568-a).

Mukhartova, Yulia; Olchev, Alexander; Shapkina, Natalia

2014-05-01

278

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)

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.

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

2010-03-01

279

Temporal and spatial variability of tidal-fluvial dynamics in the St. Lawrence fluvial estuary: An application of nonstationary tidal harmonic analysis  

NASA Astrophysics Data System (ADS)

tides in upstream reaches of rivers is a challenge, because tides are highly nonlinear and nonstationary, and accurate short-time predictions of river flow are hard to obtain. In the St. Lawrence fluvial estuary, tide forecasts are produced using a one-dimensional model (ONE-D), forced downstream with harmonic constituents, and upstream with daily discharges using 30 day flow forecasts from Lake Ontario and the Ottawa River. Although this operational forecast system serves its purpose of predicting water levels, information about nonstationary tidal-fluvial processes that can be gained from it is limited, particularly the temporal changes in mean water level and tidal properties (i.e., constituent amplitudes and phases), which are function of river flow and ocean tidal range. In this paper, a harmonic model adapted to nonstationary tides, NS_TIDE, was applied to the St. Lawrence fluvial estuary, where the time-varying external forcing is directly built into the tidal basis functions. Model coefficients from 13 analysis stations were spatially interpolated to allow tide predictions at arbitrary locations as well as to provide insights into the spatiotemporal evolution of tides. Model hindcasts showed substantial improvements compared to classical harmonic analyses at upstream stations. The model was further validated by comparison with ONE-D predictions at a total of 32 stations. The slightly lower accuracy obtained with NS_TIDE is compensated by model simplicity, efficiency, and capacity to represent stage and tidal variations in a very compact way and thus represents a new means for understanding tidal rivers.

Matte, Pascal; Secretan, Yves; Morin, Jean

2014-09-01

280

Application  

Cancer.gov

Application To apply, either email, fax, or mail the following information postmarked by December 31, 2008 to the address below: Curriculum Vitae (that includes complete address, street address, telephone, fax and e-mail) or resume; Two (2) letters

281

Modularizing Spatial Ontologies for Assisted Living Systems  

NASA Astrophysics Data System (ADS)

Assisted living systems are intended to support daily-life activities in user homes by automatizing and monitoring behavior of the environment while interacting with the user in a non-intrusive way. The knowledge base of such systems therefore has to define thematically different aspects of the environment mostly related to space, such as basic spatial floor plan information, pieces of technical equipment in the environment and their functions and spatial ranges, activities users can perform, entities that occur in the environment, etc. In this paper, we present thematically different ontologies, each of which describing environmental aspects from a particular perspective. The resulting modular structure allows the selection of application-specific ontologies as necessary. This hides information and reduces complexity in terms of the represented spatial knowledge and reasoning practicability. We motivate and present the different spatial ontologies applied to an ambient assisted living application.

Hois, Joana

282

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)

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.

Donovan, David C.

2011-12-01

283

High-spatial-resolution remote sensing  

Microsoft Academic Search

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

Tomas Brandtberg; Timothy Warner

284

Spatial Latent Class Analysis Model for Spatially Distributed Multivariate Binary Data  

PubMed Central

A spatial latent class analysis model that extends the classic latent class analysis model by adding spatial structure to the latent class distribution through the use of the multinomial probit model is introduced. Linear combinations of independent Gaussian spatial processes are used to develop multivariate spatial processes that are underlying the categorical latent classes. This allows the latent class membership to be correlated across spatially distributed sites and it allows correlation between the probabilities of particular types of classes at any one site. The number of latent classes is assumed fixed but is chosen by model comparison via cross-validation. An application of the spatial latent class analysis model is shown using soil pollution samples where 8 heavy metals were measured to be above or below government pollution limits across a 25 square kilometer region. Estimation is performed within a Bayesian framework using MCMC and is implemented using the OpenBUGS software. PMID:20161235

Wall, Melanie M.; Liu, Xuan

2009-01-01

285

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

SciTech Connect

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.

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

286

Part I: temporal and spatial distribution of multiclass pesticide residues in lake waters of Northern Greece: application of an optimized SPE-UPLC-MS/MS pretreatment and analytical method.  

PubMed

The present work describes the application of an analytical procedure, utilizing ultra performance liquid chromatography (UPLC) coupled with mass spectrometry instrumentation, for the determination of 253 multiclass pesticides, classified in six different groups. Solid phase extraction was applied for the isolation and pre-concentration of target compounds in water samples. Surface waters of the lakes located in Northern Greece (Volvi, Doirani, and Kerkini), were collected in two time periods (fall/winter 2010 and spring/summer 2011) and analyzed, applying the developed analytical methods. Spatial distribution of detected pesticides was visualized using interpolation methods and geographical information systems (GIS). Pesticides with maximum concentrations were amitrole, propoxur, simazine, chlorpyrifos, carbendazim, triazophos, disulfoton-sulfone, pyridaben, sebuthylazine, terbuthylazine, atrazine, atrazine-desethyl, bensulfuron-methyl, metobromuron, metribuzin, rotenone, pyriproxyfen, and rimsulfuron. In Lake Kerkini, mainly carbamates and triazines were determined at elevated concentrations, near the coastal point of the NW side of the lake. Seasonal variations were strong among the applied pesticide classes and determined concentrations, indicating the contribution of pesticide application patterns and rainfall. Lake Doirani exhibited organophosphate pesticides at higher concentrations mainly at coastal points, while triazines emerged as the main pollutant during spring sampling. Lake Volvi exhibited the highest pesticide concentrations, mostly triazines and ureas at the central part of the lake. The occurrence of extreme values and nonconstant seasonal variations indicated that the concentrations were increased disproportionately during the second sampling, as a result of the varying contribution of pollution sources right after the application period. In all cases, the total concentration of pesticides increased during the second sampling period. PMID:24696214

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

2014-06-01

287

Qualitative spatial reasoning for direction relation  

NASA Astrophysics Data System (ADS)

In geographic space, there are there main spatial relations among spatial entities, which are topological relation, direction relation and distance relation. Because spatial relation theories and researches directly influence the design, develop and application of GIS system, it attaches greatly importance to international GIS and interrelated academe. Qualitative spatial reasoning forms an important part of the commonsense reasoning required for building intelligent GIS. Because of the complexity and uncertainty inherent in spatial issues, the description and reasoning of spatial relation often use qualitative method in accordance with spatial cognition. Because direction relation is one of the most frequent qualitative spatial reasoning factors used in everyday life, the qualitative direction relation reasoning is a kind of important qualitative spatial reasoning. In this paper, we focus our efforts on the problem of reasoning the direction relation between regions that are composed of sets of polygons. According to the number of direction relation elements, direction relation can be divided into monomial direction relation (including one direction relation element only) and multinomial direction relation (including more than one direction relation elements); and the reference frame of direction relation can be divided into one reference frame and two reference frames. Previous methods always abstract regions into points or approximately equal in their size under two reference frames. In order to have meticulously reasoning results, we proposed a method of qualitative spatial reasoning for direction relation based on one reference frame under four different kinds of situations, that is monomial and monomial direction relation reasoning, multinomial and monomial direction relation reasoning, monomial and multinomial direction relation reasoning, multinomial and multinomial direction relation reasoning. In addition, a prototype system and a case study are carried out, and the future research problems and directions about qualitative spatial reasoning for direction relation are also discussed.

Chen, Penggen; Wu, Jing; Li, Dajun; Liu, Xingquan

2007-06-01

288

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

PubMed

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

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

289

Cosmological backreaction and spatially averaged spatial curvature  

E-print Network

It has been suggested that the accelerated expansion of the Universe is due to backreaction of small scale density perturbations on the large scale spacetime geometry. While evidence against this suggestion has accumulated, it has not yet been definitively ruled out. Many investigations of this issue have focused on the Buchert formalism, which computes spatial averages of quantities in synchronous comoving gauge. We argue that, for the deceleration parameter of this formalism to agree with observations, the spatial average of the three dimensional Ricci scalar (spatial curvature) must be large today, with an $\\Omega_k$ in the range of $1 \\le \\Omega_k \\le 1.3$. We argue that this constraint is difficult to reconcile with observations of the location of the first Doppler peak of the CMBR. We illustrate the argument with a simple toy model for the effect of backreaction, which we show is generically incompatible with observations.

Eran Rosenthal; Éanna É. Flanagan

2008-09-11

290

Quantify spatial relations to discover handwritten graphical symbols  

NASA Astrophysics Data System (ADS)

To model a handwritten graphical language, spatial relations describe how the strokes are positioned in the 2-dimensional space. Most of existing handwriting recognition systems make use of some predefined spatial relations. However, considering a complex graphical language, it is hard to express manually all the spatial relations. Another possibility would be to use a clustering technique to discover the spatial relations. In this paper, we discuss how to create a relational graph between strokes (nodes) labeled with graphemes in a graphical language. Then we vectorize spatial relations (edges) for clustering and quantization. As the targeted application, we extract the repetitive sub-graphs (graphical symbols) composed of graphemes and learned spatial relations. On two handwriting databases, a simple mathematical expression database and a complex flowchart database, the unsupervised spatial relations outperform the predefined spatial relations. In addition, we visualize the frequent patterns on two text-lines containing Chinese characters.

Li, Jinpeng; Mouchère, Harold; Viard-Gaudin, Christian

2012-01-01

291

A spatial statistical operator applied to multidate satellite imagery for identification of coral reef stress  

Microsoft Academic Search

We examine the potential for a spatial operator to highlight the change in the spatial homogeneity of a coral reef over time from satellite imagery. The Getis statistic may be used to quantify the degree of spatial homogeneity or heterogeneity of a spatial data set. We test the application for sequential SPOT imagery that includes a coral reef in the

Ellsworth F LeDrew; Heather Holden; Michael A Wulder; Chris Derksen; Candace Newman

2004-01-01

292

Application  

Microsoft Academic Search

\\u000a This chapter serves two major purposes. First of all it outlines general usage domains for the enMedia framework that has\\u000a been presented in this book. The second purpose is to demonstrate in detail the application of the enMedia framework and its\\u000a prototype implementation, SilkRoad, through a sequence of electronic negotiation scenario cases. In these cases, specific emphasis is set on

Michael Ströbel

293

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

ERIC Educational Resources Information Center

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.…

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

2009-01-01

294

Spatially extended atmospheric plasma arrays  

Microsoft Academic Search

This paper reports a systematic study of spatially extended atmospheric\\u000a plasma (SEAP) arrays employing many parallel plasma jets packed densely\\u000a and arranged in an honeycomb configuration. The work is motivated by the\\u000a challenge of using inherently small atmospheric plasmas to address many\\u000a large-scale processing applications including plasma medicine. The first\\u000a part of the study considers a capillary-ring electrode configuration as

Z. Cao; Q. Nie; D. L. Bayliss; J. L. Walsh; C. S. Ren; D. Z. Wang; M. G. Kong

2010-01-01

295

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

PubMed

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. PMID:25363649

Xiao, Fang-Xing; Hung, Sung-Fu; Tao, Hua Bing; Miao, Jianwei; Yang, Hong Bin; Liu, Bin

2014-12-21

296

Entropy, complexity, and spatial information  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

297

Entropy, complexity, and spatial information  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

298

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

299

Bibliography of spatial interferometry in optical astronomy  

NASA Technical Reports Server (NTRS)

The Bibliography of Spatial Interferometry in Optical Astronomy is a guide to the published literature in applications of spatial interferometry techniques to astronomical observations, theory and instrumentation at visible and infrared wavelengths. The key words spatial and optical define the scope of this discipline, distinguishing it from spatial interferometry at radio wavelengths, interferometry in the frequency domain applied to spectroscopy, or more general electro-optics theoretical and laboratory research. The main bibliography is a listing of all technical articles published in the international scientific literature and presented at the major international meetings and workshops attended by the spatial interferometry community. Section B summarizes publications dealing with the basic theoretical concepts and algorithms proposed and applied to optical spatial interferometry and imaging through a turbulent atmosphere. The section on experimental techniques is divided into twelve categories, representing the most clearly identified major areas of experimental research work. Section D, Observations, identifies publications dealing specifically with observations of astronomical sources, in which optical spatial interferometry techniques have been applied.

Gezari, Daniel Y.; Roddier, Francois; Roddier, Claude

1990-01-01

300

Architectural Implications for Spatial Object Association Algorithms  

SciTech Connect

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).

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

2009-01-29

301

A spatial light modulator for terahertz beams  

SciTech Connect

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.

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

2009-01-01

302

Architectural Implications for Spatial Object Association Algorithms*  

PubMed Central

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).

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

2013-01-01

303

Spatial filters for complex wavefront modulation.  

PubMed

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

Sarkadi, Tamás; Kettinger, Ádám; Koppa, Pál

2013-08-01

304

Generalizing the spatial relative risk function.  

PubMed

The spatial relative risk function is defined as the ratio of densities describing respectively the spatial distribution of cases and controls. It has proven to be an effective tool for visualizing spatial variation in risk in many epidemiological applications over the past 20 years. We discuss the generalization of this function to spatio-temporal case-control data, and also to situations where there are covariates available that may affect the spatial patterns of disease. We examine estimation of the generalized relative risk functions using kernel smoothing, including asymptotic theory and data-driven bandwidth selection. We also consider construction of tolerance contours. Our methods are illustrated on spatio-temporal data describing the 2001 outbreak of foot-and-mouth disease in the United Kingdom, with farm size as a covariate. PMID:24606990

Sarojinie Fernando, W T P; Hazelton, Martin L

2014-04-01

305

Arbitrary manipulation of spatial amplitude and phase using phase-only spatial light modulators  

PubMed Central

Spatial structure of a light beam is an important degree of freedom to be extensively explored. By designing simple configurations with phase-only spatial light modulators (SLMs), we show the ability to arbitrarily manipulate the spatial full field information (i.e. amplitude and phase) of a light beam. Using this approach to facilitating arbitrary and independent control of spatial amplitude and phase, one can flexibly generate different special kinds of light beams for different specific applications. Multiple collinear orbital angular momentum (OAM) beams, Laguerre-Gaussian (LG) beams, and Bessel beams, having both spatial amplitude and phase distributions, are successfully generated in the experiments. Some arbitrary beams with odd-shaped intensity are also generated in the experiments. PMID:25501584

Zhu, Long; Wang, Jian

2014-01-01

306

Universit Libre de Bruxelles Facult de Sciencies Appliques  

E-print Network

de la Décision (CoDE) Conventional, Spatial, and Temporal Data Warehouses: Concepts and Design insight and control over costs Promotion are failing for unknown reasons There is high cost of inventory operational databases 90's: Data warehousing with integrated OLAP engine #12;5 Presentation plan OLAP concepts

Libre de Bruxelles, Université

307

Spatially confined assembly of nanoparticles.  

PubMed

The ability to assemble NPs into ordered structures that are expected to yield collective physical or chemical properties has afforded new and exciting opportunities in the field of nanotechnology. Among the various configurations of nanoparticle assemblies, two-dimensional (2D) NP patterns and one-dimensional (1D) NP arrays on surfaces are regarded as the ideal assembly configurations for many technological devices, for example, solar cells, magnetic memory, switching devices, and sensing devices, due to their unique transport phenomena and the cooperative properties of NPs in assemblies. To realize the potential applications of NP assemblies, especially in nanodevice-related applications, certain key issues must still be resolved, for example, ordering and alignment, manipulating and positioning in nanodevices, and multicomponent or hierarchical structures of NP assemblies for device integration. Additionally, the assembly of NPs with high precision and high levels of integration and uniformity for devices with scaled-down dimensions has become a key and challenging issue. Two-dimensional NP patterns and 1D NP arrays are obtained using traditional lithography techniques (top-down strategies) or interfacial assembly techniques (bottom-up strategies). However, a formidable challenge that persists is the controllable assembly of NPs in desired locations over large areas with high precision and high levels of integration. The difficulty of this assembly is due to the low efficiency of small features over large areas in lithography techniques or the inevitable structural defects that occur during the assembly process. The combination of self-assembly strategies with existing nanofabrication techniques could potentially provide effective and distinctive solutions for fabricating NPs with precise position control and high resolution. Furthermore, the synergistic combination of spatially mediated interactions between nanoparticles and prestructures on surfaces may play an increasingly important role in the controllable assembly of NPs. In this Account, we summarize our approaches and progress in fabricating spatially confined assemblies of NPs that allow for the positioning of NPs with high resolution and considerable throughput. The spatially selective assembly of NPs at the desired location can be achieved by various mechanisms, such as, a controlled dewetting process, electrostatically mediated assembly of particles, and confined deposition and growth of NPs. Three nanofabrication techniques used to produce prepatterns on a substrate are summarized: the Langmuir-Blodgett (LB) patterning technique, e-beam lithography (EBL), and nanoimprint lithography (NPL). The particle density, particle size, or interparticle distance in NP assemblies strongly depends on the geometric parameters of the template structure due to spatial confinement. In addition, with smart design template structures, multiplexed NPs can be assembled into a defined structure, thus demonstrating the structural and functional complexity required for highly integrated and multifunction applications. PMID:25244100

Jiang, Lin; Chen, Xiaodong; Lu, Nan; Chi, Lifeng

2014-10-21

308

A Spatial and Temporal Analysis of Dolphin  

E-print Network

1 A Spatial and Temporal Analysis of Dolphin Community Structure in Southeastern North Carolina Dr structure of Atlantic bottlenose dolphins · GIS applications to scientific studies: Bowyer 1995; Stone et al. 1997; Gerrard et al. 2001; Selkirk and Bishop 2002 3 Bottlenose Dolphins and Community Structure · Open

Wright, Dawn Jeannine

309

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 ...

310

MAPPING SPATIAL ACCURACY AND ESTIMATING LANDSCAPE INDICATORS FROM THEMATIC LAND COVER MAPS USING FUZZY SET THEORY  

EPA Science Inventory

The accuracy of thematic map products is not spatially homogenous, but instead variable across most landscapes. Properly analyzing and representing the spatial distribution (pattern) of thematic map accuracy would provide valuable user information for assessing appropriate applic...

311

2009 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics October 18-21, 2009, New Paltz, NY MULTIZONE 2D SOUNDFIELD REPRODUCTION VIA SPATIAL BAND STOP FILTERS  

E-print Network

, New Paltz, NY MULTIZONE 2D SOUNDFIELD REPRODUCTION VIA SPATIAL BAND STOP FILTERS Yan Jennifer Wu-zone soundfield. Index Terms-- soundfield reproduction, multizone, cylindri- cal harmonic expansions, spatial band stop filters. 1. INTRODUCTION Reproduction of multiple independent soundfields in separate zones over

Abhayapala, Thushara D.

312

Spatial Coherence of winds and waves over the Arabian Sea and Bay of Bengal and their evolution during SW Monsoon: a novel application of along-track Radar Altimeter measurements from Space  

NASA Astrophysics Data System (ADS)

We have examined, for the first time, the spatial coherence of oceanic parameters, namely, the ocean surface wind and significant wave height (SWH), using near-instantaneous along-track sampling over vast oceanic tracks provided by Poseidon-2 Radar Altimeter onboard Jason-1. The spatial coherence length scales over the Arabian Sea and the Bay of Bengal regions, derived using Auto correlation analysis, display interesting characteristics in relation to onset and evolution of SW Monsoon over India. The estimated spatial coherence scales are found to be of the order of 100-500 km. Generally, SWH coherence lengths over Arabian Sea are observed to increase from June to July during good monsoon year (2012). This trend is not followed for the poor monsoon year (2002). Similar trend is observed for spatial coherence scales for wind speed. The temporal evolution of analyzed spatial coherence scales of winds and waves over Arabian Sea clearly brings out the distinction between a "good" (2012) and a "poor" (2002) monsoon year. The spatial coherence lengths of these parameters over the Bay of Bengal are found to be shorter and do not show any systematic relation to onset and evolution of SW monsoon. Anisotropy in coherence lengths is also analyzed by treating ascending and descending tracks separately. Generally, the descending tracks measurements show higher spatial coherence lengths than the ascending ones. Like the spatial coherence scales, the anisotropy of the coherence scales over the Arabian Sea also mimics the behaviour of the strength of SW Monsoon.

Bhandari, S. M.; Hareef Baba Shaeb, K.

2014-11-01

313

Mapping spatial relations  

E-print Network

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 ...

Kasturirangan, Rajesh, 1971-

2004-01-01

314

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)

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

Xiao, Fang-Xing; Hung, Sung-Fu; Tao, Hua Bing; Miao, Jianwei; Yang, Hong Bin; Liu, Bin

2014-11-01

315

Modeling Topological Constraints in Spatial Part-Whole Relationships  

Microsoft Academic Search

Abstract To facilitate development of spatial applications, we investigate the problem of modeling topological constraints in part - whole relationships between spatial objects, where the related objects may themselves be composite An example would be countries that belong to a supranational organization, where the countries are themselves composed of states Current topological classification schemes are restricted to simple, bounded, regular,

Rosanne Price; Nectaria Tryfona; Christian S. Jensen

2001-01-01

316

AN INTEGRATED SPATIAL STATISTICS PACKAGE FOR MAP DATA ANALYSIS  

Microsoft Academic Search

In the analysis of geocoded statistical data, common practice has been to treat the data in isolation from its locational or spatial characteristics. This results in a potentially critical loss of the spatial information that is contained in the mapped representation of the statisti cal data but not in the application of aspatial statistical techniques such as cross-sectional regression. One

Barry J. Glick; Stephen A. Hirsch

317

R-trees: a dynamic index structure for spatial searching  

Microsoft Academic Search

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

Antonin Guttman

1984-01-01

318

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...

319

Virtual Reality Rehabilitation of Spatial Abilities after Brain Damage  

E-print Network

Virtual Reality Rehabilitation of Spatial Abilities after Brain Damage Sebastian T. KOENIGA and to quantify functional improvements, this project aims at developing a virtual reality (VR) application functionality and data acquisition are being implemented. Keywords: Virtual Reality, Neuropsychological

Hickman, Mark

320

Reconstructing Spatial Distributions from Anonymized Locations  

SciTech Connect

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.

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

321

Spatial Strategies and Spatial Training in the Collegiate Curriculum.  

ERIC Educational Resources Information Center

This paper discusses the results of two studies both dealing with spatial abilities and training. The first investigated the kinds of spatial strategies and personal experiences, both nonacademic and academic, that distinguish students preparing for high spatial careers from others. The second study focused on the effectiveness of spatial training…

Baker, Justine C.

322

Spatial Concepts and Spatial Reasoning in the Social Sciences  

E-print Network

to measure understanding, learning, & skill development spatial@ucsb Focus: · Geospatial concepts in socialSpatial Concepts and Spatial Reasoning in the Social Sciences (an agenda for undergraduate of spatial thinking into processes for learning and discovery in the natural, social, and behavioral

Fabrikant, Sara Irina

323

Dealing with spatial heterogeneity  

NASA Astrophysics Data System (ADS)

Heterogeneity can be dealt with by defining homogeneous equivalent properties, known as averaging, or by trying to describe the spatial variability of the rock properties from geologic observations and local measurements. The techniques available for these descriptions are mostly continuous Geostatistical models, or discontinuous facies models such as the Boolean, Indicator or Gaussian-Threshold models and the Markov chain model. These facies models are better suited to treating issues of rock strata connectivity, e.g. buried high permeability channels or low permeability barriers, which greatly affect flow and, above all, transport in aquifers. Genetic models provide new ways to incorporate more geology into the facies description, an approach that has been well developed in the oil industry, but not enough in hydrogeology. The conclusion is that future work should be focused on improving the facies models, comparing them, and designing new in situ testing procedures (including geophysics) that would help identify the facies geometry and properties. A world-wide catalog of aquifer facies geometry and properties, which could combine site genesis and description with methods used to assess the system, would be of great value for practical applications. On peut aborder le problème de l'hétérogénéité en s'efforçant de définir une perméabilité équivalente homogène, par prise de moyenne, ou au contraire en décrivant la variation dans l'espace des propriétés des roches à partir des observations géologiques et des mesures locales. Les techniques disponibles pour une telle description sont soit continues, comme l'approche Géostatistique, soit discontinues, comme les modèles de faciès, Booléens, ou bien par Indicatrices ou Gaussiennes Seuillées, ou enfin Markoviens. Ces modèles de faciès sont mieux capables de prendre en compte la connectivité des strates géologiques, telles que les chenaux enfouis à forte perméabilité, ou au contraire les faciès fins de barrières de perméabilité, qui ont une influence importante sur les écoulement, et, plus encore, sur le transport. Les modè les génétiques récemment apparus ont la capacité de mieux incorporer dans les modèles de faciès les observations géologiques, chose courante dans l'industrie pétrolière, mais insuffisamment développée en hydrogéologie. On conclut que les travaux de recherche ultérieurs devraient s'attacher à développer les modèles de faciès, à les comparer entre eux, et à mettre au point de nouvelles méthodes d'essais in situ, comprenant les méthodes géophysiques, capables de reconnaître la géométrie et les propriétés des faciès. La constitution d'un catalogue mondial de la géométrie et des propriétés des faciès aquifères, ainsi que des méthodes de reconnaissance utilisées pour arriver à la détermination de ces systèmes, serait d'une grande importance pratique pour les applications. La heterogeneidad se puede manejar por medio de la definición de características homogéneas equivalentes, conocidas como promediar o tratando de describir la variabilidad espacial de las características de las rocas a partir de observaciones geológicas y medidas locales. Las técnicas disponibles para estas descripciones son generalmente modelos geoestadísticos continuos o modelos de facies discontinuos como los modelos Boolean, de Indicador o de umbral de Gaussian y el modelo de cadena de Markow. Estos modelos de facies son mas adecuados para tratar la conectvidad de estratos geológicos (por ejemplo canales de alta permeabilidad enterrados o barreras de baja permeabilidad que tienen efectos importantes sobre el flujo y especialmente sobre el transporte en los acuíferos. Los modelos genéticos ofrecen nuevas formas de incorporar más geología en las descripciones de facies, un enfoque que está bien desarollado en la industria petrolera, pero insuficientemente en la hidrogeología. Se concluye que los trabajos futuros deberían estar más enfocados en mejorar los modelos de facies, en establecer comparaciones y en

Marsily, Gh.; Delay, F.; Gonçalvès, J.; Renard, Ph.; Teles, V.; Violette, S.

2005-03-01

324

Making a Place for Space: Spatial Thinking in Social Science  

PubMed Central

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

Logan, John R.

2013-01-01

325

Heredity Factors in Spatial Visualization.  

ERIC Educational Resources Information Center

Spatial visualization is not yet clearly understood. Some researchers have concluded that two factors or abilities are involved, spatial orientation and spatial visualization. Different definitions and different tests have been proposed for these two abilities. Several studies indicate that women generally perform more poorly on spatial tests than…

Vandenberg, S. G.

326

The Spatial Standard Observer  

NASA Technical Reports Server (NTRS)

The spatial standard observer is a computational model that provides a measure of the visibility of a target in a uniform background image or of the visual discriminability of two images. Standard observers have long been used in science and industry to quantify the discriminability of colors. Color standard observers address the spectral characteristics of visual stimuli, while the spatial standard observer (SSO), as its name indicates, addresses spatial characteristics. The SSO is based on a model of human vision. The SSO was developed in a process that included evaluation of a number of earlier mathematical models that address optical, physiological, and psychophysical aspects of spatial characteristics of human visual perception. Elements of the prior models are incorporated into the SSO, which is formulated as a compromise between accuracy and simplicity. The SSO operates on a digitized monochrome still image or on a pair of such images. The SSO consists of three submodels that operate sequentially on the input image(s): 1. A contrast model, which converts an input monochrome image to a luminance contrast image, wherein luminance values are expressed as excursions from, and normalized to, a mean; 2. A contrast-sensitivity-filter model that includes an oblique-effect filter (which accounts for the decline in contrast sensitivity at oblique viewing angles); and 3. A spatial summation model, in which responses are spatially pooled by raising each pixel to the power beta, adding the results, and raising the sum to the 1/b power. In this model, b=2.9 was found to be a suitable value. The net effect of the SSO is to compute a numerical measure of the perceptual strength of the single image, or of the visible difference (denoted the perceptual distance) between two images. The unit of a measure used in the SSO is the just noticeable difference (JND), which is a standard measure of perceptual discriminability. A target that is just visible has a measure of 1 JND.

Watson, Andrew B.; Ahumada, Albert J, Jr.

2006-01-01

327

Spatial pattern of diarrhea based on regional economic and environment by spatial autoregressive model  

NASA Astrophysics Data System (ADS)

The diarrhea case pattern information, especially for toddler, is very important. It is used to show the distribution of diarrhea in every region, relationship among that locations, and regional economic characteristic or environmental behavior. So, this research uses spatial pattern to perform them. This method includes: Moran's I, Spatial Autoregressive Models (SAR), and Local Indicator of Spatial Autocorrelation (LISA). It uses sample from 23 sub districts of Bekasi Regency, West Java, Indonesia. Diarrhea case, regional economic, and environmental behavior of households have a spatial relationship among sub district. SAR shows that the percentage of Regional Gross Domestic Product is significantly effect on diarrhea at ? = 10%. Therefore illiteracy and health center facilities are significant at ? = 5%. With LISA test, sub districts in southern Bekasi have high dependencies with Cikarang Selatan, Serang Baru, and Setu. This research also builds development application that is based on java and R to support data analysis.

Bekti, Rokhana Dwi; Nurhadiyanti, Gita; Irwansyah, Edy

2014-10-01

328

Spatial symmetry breaking in rapidly rotating convective spherical shells  

NASA Technical Reports Server (NTRS)

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.

Zhang, Keke; Schubert, Gerald

1995-01-01

329

High Spatial Resolution Remotely Sensed Data for Ecosystem Characterization  

NSDL National Science Digital Library

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.

MICHAEL A. WULDER, RONALD J. HALL, NICHOLAS C. COOPS, and STEVEN E. FRANKLIN (;)

2004-06-01

330

The Impact of Spatial Scales and Spatial Smoothing on the Outcome of Bayesian Spatial Model  

PubMed Central

Discretization of a geographical region is quite common in spatial analysis. There have been few studies into the impact of different geographical scales on the outcome of spatial models for different spatial patterns. This study aims to investigate the impact of spatial scales and spatial smoothing on the outcomes of modelling spatial point-based data. Given a spatial point-based dataset (such as occurrence of a disease), we study the geographical variation of residual disease risk using regular grid cells. The individual disease risk is modelled using a logistic model with the inclusion of spatially unstructured and/or spatially structured random effects. Three spatial smoothness priors for the spatially structured component are employed in modelling, namely an intrinsic Gaussian Markov random field, a second-order random walk on a lattice, and a Gaussian field with Matérn correlation function. We investigate how changes in grid cell size affect model outcomes under different spatial structures and different smoothness priors for the spatial component. A realistic example (the Humberside data) is analyzed and a simulation study is described. Bayesian computation is carried out using an integrated nested Laplace approximation. The results suggest that the performance and predictive capacity of the spatial models improve as the grid cell size decreases for certain spatial structures. It also appears that different spatial smoothness priors should be applied for different patterns of point data. PMID:24146799

Kang, Su Yun; McGree, James; Mengersen, Kerrie

2013-01-01

331

RADSS: an integration of GIS, spatial statistics, and network service for regional data mining  

NASA Astrophysics Data System (ADS)

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.

Hu, Haitang; Bao, Shuming; Lin, Hui; Zhu, Qing

2005-10-01

332

Visualization of large spatial data in networking environments  

NASA Astrophysics Data System (ADS)

Rendering and interacting with high-resolution geographical data sets and complex models have become integral parts in a 3D GIS, in particular, in a web-based 3D GIS. Due to large data sets and narrow network bandwidth, general-purpose GIS can no longer visualize and manipulate these spatial data over networks in real time. This paper explores a way for building a Web-based 3D GIS application. The application aims to visualize and analyze large spatial data sets. We propose a novel 3D data model for representing the features of the terrain surface and 3D objects. A server-client architecture including progressive transmission methods and multiresolution representations are presented to help create the application. Together with a spatial index, the application provides an effective way for powerful access and manipulation of large-scale data sets. Finally, an experiment is performed using the geo-data to verify that the application works appropriately.

Zhang, Liqiang; Yang, Chongjun; Tong, Xiaohua; Rui, Xiaoping

2007-09-01

333

Spatial Dynamics of Marketplaces  

Microsoft Academic Search

Marketplaces are a common topic in literature. However, the questions with their spatial theories have been often subject to the discussions at a level of more abstract concepts or socio-economic factors rather than their actual layouts. This common tendency seems to engender some considerable problems in our theoretical understanding of marketplaces and how they actually work. In fact, the false

I C Istek

334

Handbook of Spatial Cognition  

ERIC Educational Resources Information Center

Spatial cognition is a branch of cognitive psychology that studies how people acquire and use knowledge about their environment to determine where they are, how to obtain resources, and how to find their way home. Researchers from a wide range of disciplines, including neuroscience, cognition, and sociology, have discovered a great deal about how…

Waller, David, Ed.; Nadel, Lynn, Ed.

2012-01-01

335

Spatialized Transfer Functions  

Microsoft Academic Search

Multi-dimensional transfer functions are an efcient way to visualize features in scalar volume data produced by CT or MRI scanners. However, the optimal transfer function is difcult to nd in general. We present an automatic yet powerful method for the automatic setup of multi-dimensional transfer functions by adding spatial information to the histogram of a volume. Using this information we

Stefan Röttger; Michael Bauer; Marc Stamminger

2005-01-01

336

UPDATE SPATIAL ALLOCATION FILES  

EPA Science Inventory

SMOKE-ready and EMS-HAP-ready spatial allocation files that can be used to allocate 1999 emissions and their derivatives (e.g., 1999 NEI and 2001 modeling platform) from the county level to modeling grid cells (36, 12 and 4 kilometer) and to census tracts....

337

Cartography: LACIE's spatial processor  

NASA Technical Reports Server (NTRS)

The spatial processing needs of LACIE include the location of agricultural test sites, and the registration of ground truth to LANDSAT imagery. The technological aspects of LACIE cartographic support, the need for cartography in satellite crop surveys, and proposed improvements which would enhance support of future programs are discussed.

Rader, M. L.; Vela, R. R. (principal investigators)

1979-01-01

338

ECOREGION SPATIAL DATABASE  

EPA Science Inventory

This spatial database contains boundaries and attributes describing Level III ecoregions in EPA Region 8. The ecoregions shown here have been derived from Omernik (1987) and from refinements of Omernik's framework that have been made for other projects. These ongoing or re...

339

Optimization techniques for integrating spatial data  

USGS Publications Warehouse

Two optimization techniques ta predict a spatial variable from any number of related spatial variables are presented. The applicability of the two different methods for petroleum-resource assessment is tested in a mature oil province of the Midcontinent (USA). The information on petroleum productivity, usually not directly accessible, is related indirectly to geological, geophysical, petrographical, and other observable data. This paper presents two approaches based on construction of a multivariate spatial model from the available data to determine a relationship for prediction. In the first approach, the variables are combined into a spatial model by an algebraic map-comparison/integration technique. Optimal weights for the map comparison function are determined by the Nelder-Mead downhill simplex algorithm in multidimensions. Geologic knowledge is necessary to provide a first guess of weights to start the automatization, because the solution is not unique. In the second approach, active set optimization for linear prediction of the target under positivity constraints is applied. Here, the procedure seems to select one variable from each data type (structure, isopachous, and petrophysical) eliminating data redundancy. Automating the determination of optimum combinations of different variables by applying optimization techniques is a valuable extension of the algebraic map-comparison/integration approach to analyzing spatial data. Because of the capability of handling multivariate data sets and partial retention of geographical information, the approaches can be useful in mineral-resource exploration. ?? 1995 International Association for Mathematical Geology.

Herzfeld, U.C.; Merriam, D.F.

1995-01-01

340

Children's spatial thinking: does talk about the spatial world matter?  

PubMed

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 child age 14 to 46 months in a diverse sample of 52 parent-child dyads interacting in their home settings. These same children were given three non-verbal spatial tasks, items from a Spatial Transformation task (Levine et al., 1999), the Block Design subtest from the WPPSI-III (Wechsler, 2002), and items on the Spatial Analogies subtest from Primary Test of Cognitive Skills (Huttenlocher & Levine, 1990) at 54 months of age. We find that parents vary widely in the amount of spatial language they use with their children during everyday interactions. This variability in spatial language input, in turn, predicts the amount of spatial language children produce, controlling for overall parent language input. Furthermore, children who produce more spatial language are more likely to perform better on spatial problem solving tasks at a later age. PMID:22010900

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

2011-11-01

341

Algorithms for spatial scaling of net primary productivity using subpixel information  

Microsoft Academic Search

Spatial scaling is of particular importance in remote sensing applications to terrestrial ecosystems where spatial heterogeneity is the norm. Surface parameters derived at different resolutions can be considerably different even though they are derived using the same algorithms or models. This article addresses issues related to spatial scaling of net primary productivity (NPP). The main objective is to develop algorithms

Anita Zelic; Jing M. Chen; Jane Liu; Ferko Csillag

2002-01-01

342

Seasonal and interannual variations in spatial autocorrelation statistics of tropical precipitation  

Microsoft Academic Search

Spatial autocorrelation of tropical precipitation is examined by the application of Moran's I index to the 17- year CMAP data set. Global I indices, which express the overall spatial autocorrelation of precipitation for the entire tropics, have an annual cycle characterized by bimodalism. A higher degree of spatial organization of tropical precipitation occurs during both boreal and austral summers. While

Wai-Lok Siu

1997-01-01

343

Spatial localization in heterogeneous systems.  

PubMed

We study spatial localization in the generalized Swift-Hohenberg equation with either quadratic-cubic or cubic-quintic nonlinearity subject to spatially heterogeneous forcing. Different types of forcing (sinusoidal or Gaussian) with different spatial scales are considered and the corresponding localized snaking structures are computed. The results indicate that spatial heterogeneity exerts a significant influence on the location of spatially localized structures in both parameter space and physical space, and on their stability properties. The results are expected to assist in the interpretation of experiments on localized structures where departures from spatial homogeneity are generally unavoidable. PMID:24580293

Kao, Hsien-Ching; Beaume, Cédric; Knobloch, Edgar

2014-01-01

344

Spatial localization in heterogeneous systems  

NASA Astrophysics Data System (ADS)

We study spatial localization in the generalized Swift-Hohenberg equation with either quadratic-cubic or cubic-quintic nonlinearity subject to spatially heterogeneous forcing. Different types of forcing (sinusoidal or Gaussian) with different spatial scales are considered and the corresponding localized snaking structures are computed. The results indicate that spatial heterogeneity exerts a significant influence on the location of spatially localized structures in both parameter space and physical space, and on their stability properties. The results are expected to assist in the interpretation of experiments on localized structures where departures from spatial homogeneity are generally unavoidable.

Kao, Hsien-Ching; Beaume, Cédric; Knobloch, Edgar

2014-01-01

345

Business Intelligence for Home Care Source Data and ETL Process  

E-print Network

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

Kaiserslautern, Universität

346

Abstract--Data mining aims at extraction of previously unidentified information from large databases. It can be  

E-print Network

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

Fong, Chi Chiu "Simon"

347

Statistical Analysis of Spatial Crime Data  

Microsoft Academic Search

\\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

Wim Bernasco; Henk Elffers

348

Spatial Indexing for Location-Aware Systems  

Microsoft Academic Search

As location systems provide increasingly fine- grained locations for mobile entities, location-aware systems that react appropriately and autonomously to location events will be in demand. Although much research has been devoted to indexing schemes for very large scale GIS applications (where the systems are predominantly query-based), comparably little attention has been given to the use of spatial indexing within location-aware

Robert K. Harle

2007-01-01

349

Geometry and Spatial Relations: Sidewalk Capers  

NSDL National Science Digital Library

In this 28-minute professional development video, teachers focus on geometry and spatial relations by having students explore shapes that tessellate and have the same area. Teachers from different grade levels collaborate on what they want their students to be able to understand and accomplish. Viewers can watch how a 3rd-grade teacher guides his students in understanding area through the application of tessellations. Support Materials includes a Sidewalk Capers Lesson Plan.

Mathline; Portis, Chris

1997-01-01

350

Symbolic and spatial database for structural biology  

Microsoft Academic Search

This paper describes the development of a database to support three-dimensional image reconstruction of structural biology using objectoriented technology. The requirements of this system encompass many of the popular justifications for the application of object-oriented technology, such as non-standard data types and complex composite data, but we also find advantage in the increased functionality obtained for spatial relationship operations and

Dan Benson; Greg Zick

1991-01-01

351

Improving the quality of spatial quantum channels  

E-print Network

We show, for the non-Markovian or time-dependent Markovian process, by breaking up a spatial quantum channel (SQC) into a series of periodically arranged sub-components, that the quality of information transmission described by the purity, fidelity and concurrence of the output states can be improved. The relation to the quantum zero effect and possible applications of the idea have been discussed.

Ning Tang; Zi-Long Fan; Hao-Sheng Zeng

2013-06-04

352

Spatial Phase Imaging  

NASA Technical Reports Server (NTRS)

Frequently, scientists grow crystals by dissolving a protein in a specific liquid solution, and then allowing that solution to evaporate. The methods used next have been, variously, invasive (adding a dye that is absorbed by the protein), destructive (crushing protein/salt-crystal mixtures and observing differences between the crushing of salt and protein), or costly and time-consuming (X-ray crystallography). In contrast to these methods, a new technology for monitoring protein growth, developed in part through NASA Small Business Innovation Research (SBIR) funding from Marshall Space Flight Center, is noninvasive, nondestructive, rapid, and more cost effective than X-ray analysis. The partner for this SBIR, Photon-X, Inc., of Huntsville, Alabama, developed spatial phase imaging technology that can monitor crystal growth in real time and in an automated mode. Spatial phase imaging scans for flaws quickly and produces a 3-D structured image of a crystal, showing volumetric growth analysis for future automated growth.

2006-01-01

353

Particle detector spatial resolution  

DOEpatents

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.

Perez-Mendez, Victor (Berkeley, CA)

1992-01-01

354

Particle detector spatial resolution  

DOEpatents

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.

Perez-Mendez, V.

1992-12-15

355

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...

356

Spatial Data Analysis  

NASA Astrophysics Data System (ADS)

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.

Haining, Robert

2003-06-01

357

The agent-based spatial information semantic grid  

NASA Astrophysics Data System (ADS)

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

Cui, Wei; Zhu, YaQiong; Zhou, Yong; Li, Deren

2006-10-01

358

Spatial forms and mental imagery.  

PubMed

Four studies investigated how general mental imagery might be involved in mediating the phenomenon of 'synaesthetic' spatial forms - i.e., the experience that sequences such as months or numbers have spatial locations. In Study 1, people with spatial forms scored higher than controls on visual imagery self-report scales. This is consistent with the suggestion that strong general imagery is at least a necessary condition to experience spatial forms. However self-reported spatial imagery did not differ between groups, suggesting either that the spatial nature of forms is mediated by special synaesthetic mechanisms, or that forms are depictive visual images rather than explicit spatial models. A methodological implication of Study 1 was that a general tendency for people with spatial forms to use imagery strategies might account for some of their previously-reported behavioural differences with control groups. This concern was supported by Studies 2-4. Normal participants were encouraged to visually image the months in various spatial layouts, and spatial associations for months were tested using left/right key presses to classify month names as belonging to the first or second half of the year (Studies 2-3) or as odd/even (Study 4). Reaction times showed month-SNARC (Spatial Numerical Association of Response Codes) effects of similar magnitude to previously-reported data from spatial form participants (Price and Mentzoni, 2008). Additionally, reversing the spatial associations within instructed images was sufficient to reverse the direction of observed month-SNARC effects (i.e., positive vs negative slope), just as different spatial forms were previously shown to modulate the direction of effects (ibid.). Results challenge whether previously observed behavioural differences between spatial form and control groups need to be explained in terms of special synaesthetic mechanisms rather than intentional imagery strategies. It is argued that usually strong general imagery processes should complement synaesthetic mechanisms as possible explanations of spatial forms. PMID:19665116

Price, Mark C

2009-01-01

359

Bayesian semiparametric model with spatially-temporally varying coefficients selection  

PubMed Central

In spatio-temporal analysis, the effect of a covariate on the outcome usually varies across areas and time. The spatial configuration of the areas may potentially depend on not only the structured random intercept but also spatially varying coefficients of covariates. In addition, the normality assumption of the distribution of spatially varying coefficients could lead to potential biases of estimations. In this article, we propose a Bayesian semiparametric space-time model where the spatially-temporally varying coefficient is decomposed as fixed, spatially varying and temporally varying coefficients. The spatially varying coefficients of space-time covariates are modeled nonparametrically by using the area-specific Dirichlet process prior with weights transformed via a generalized transformation. Temporally varying coefficients of covariates are modeled through the dynamic model. Uncertainty of inclusion of the spatially-temporally varying coefficients is also taken into account by variable selection procedure through determining the probabilities of different effects for each covariate. The proposed semiparametric approach shows the improvement compared to the Bayesian spatial-temporal models with normality assumption on spatial random effects and the Bayesian model with the Dirichlet process prior on the random intercept. A simulation example is presented to evaluate the performance of the proposed approach with the competing models. An application to low birth weight data in South Carolina is used for an illustration. PMID:23526312

Cai, Bo; Lawson, Andrew B.; Hossain, Md. Monir; Choi, Jungsoon; Kirby, Russell S.; Liu, Jihong

2013-01-01

360

Spatial Premise Integration in Hindi  

ERIC Educational Resources Information Center

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…

Mishra, Ramesh Kumar

2007-01-01

361

Spatial data mining as an  

E-print Network

Institute for the Languages of Finland 10th October 2003 #12;Spatial data mining as an onomastic tool AnttiSpatial data mining as an onomastic tool Antti Leino UNGEGN Norden Division 10.10.2003 Introduction Back Full Screen Close Quit Spatial data mining as an onomastic tool http

Leino, Antti

362

Spatial Cognition An AI Perspective  

E-print Network

Spatial Cognition An AI Perspective Christian Freksa* * Cognitive Systems Research Group and SFB/TR 8 Spatial Cognition, Universität Bremen, Germany. Email: freksa@sfbtr8.uni-bremen.de Abstract. After and spatial cognition have moved into the focus of interest in concentrated research enterprises since the mid

Bremen, Universität

363

Spatial Econometrics and Political Science  

Microsoft Academic Search

Abstract Many theories in political science predict the spatial clustering of similar behaviors among,neighboring units of observation. This spatial autocorrelation poses implications for both inference and modeling that are distinct from the more familiar serial dependence in time series analysis. In this paper, I examine how political scientists can diagnose and model the spatial dependence that is predicted by our

David Darmofal

364

Polarimetric target detection in the presence of spatially fluctuating Mueller matrices  

E-print Network

applications, the statistics of Mueller matrix fluctuations have to be taken into account to optimize on simulated and real-world images that, in practical applications, the statistics of spatial Mueller matrix one pixel to the next, the Mueller matrix randomly fluctuates around its average value. This spatial

Paris-Sud XI, Université de

365

Spatially resolved emulsion droplet sizing using inverse Abel transforms  

NASA Astrophysics Data System (ADS)

Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) is well established as a tool for determining emulsion droplet-size distributions via measurement of restricted self-diffusion. Most measurements made to date have not been spatially resolved, but have measured an average size distribution for a certain volume of emulsion. This paper demonstrates a rapid method of performing spatially resolved, restricted diffusion measurements, which enables emulsion droplet sizing to be spatially resolved as a function of radius in cylindrical geometries or pipes. This is achieved by the use of an Abel transform. The technique is demonstrated in various annular systems containing two emulsions, with different droplet-size distributions, and/or a pure fluid. It is also shown that by modifying the pulse sequence by the inclusion of flow-compensating magnetic field gradients, the technique can measure spatially resolved droplet-size distributions in flowing emulsions, with potential applications in spatially resolved on-line droplet-size analysis.

Hollingsworth, K. G.; Johns, M. L.

2005-09-01

366

Reversing desertification as a spatial resonance problem  

NASA Astrophysics Data System (ADS)

An important environmental application of pattern control by periodic spatial forcing is the restoration of vegetation patterns in water-limited ecosystems that went through desertification. Vegetation restoration is often based on periodic landscape modulations that intercept overland water flow and form favorable conditions for vegetation growth. Viewing this method as a spatial resonance problem, we show that plain realizations of this method, assuming a complete vegetation response to the imposed modulation pattern, suffer from poor resilience to rainfall variability. By contrast, less intuitive realizations, based on the inherent spatial modes of vegetation growth and involving partial vegetation implantation, can be highly resilient and equally productive. We derive these results using two complementary models, a realistic vegetation model, and a simple pattern formation model that lends itself to mathematical analysis and highlights the universal aspects of the behaviors found with the vegetation model. We focus on reversing desertification as an outstanding environmental problem, but the main conclusions hold for any spatially forced system near the onset of a finite-wave-number instability that is subjected to noisy conditions.

Mau, Yair; Haim, Lev; Meron, Ehud

2015-01-01

367

Reversing desertification as a spatial resonance problem.  

PubMed

An important environmental application of pattern control by periodic spatial forcing is the restoration of vegetation patterns in water-limited ecosystems that went through desertification. Vegetation restoration is often based on periodic landscape modulations that intercept overland water flow and form favorable conditions for vegetation growth. Viewing this method as a spatial resonance problem, we show that plain realizations of this method, assuming a complete vegetation response to the imposed modulation pattern, suffer from poor resilience to rainfall variability. By contrast, less intuitive realizations, based on the inherent spatial modes of vegetation growth and involving partial vegetation implantation, can be highly resilient and equally productive. We derive these results using two complementary models, a realistic vegetation model, and a simple pattern formation model that lends itself to mathematical analysis and highlights the universal aspects of the behaviors found with the vegetation model. We focus on reversing desertification as an outstanding environmental problem, but the main conclusions hold for any spatially forced system near the onset of a finite-wave-number instability that is subjected to noisy conditions. PMID:25679678

Mau, Yair; Haim, Lev; Meron, Ehud

2015-01-01

368

Body-specific representations of spatial location.  

PubMed

The body specificity hypothesis (Casasanto, 2009) posits that the way in which people interact with the world affects their mental representation of information. For instance, right- versus left-handedness affects the mental representation of affective valence, with right-handers categorically associating good with rightward areas and bad with leftward areas, and left-handers doing the opposite. In two experiments we test whether this hypothesis can: extend to spatial memory, be measured in a continuous manner, be predicted by extent of handedness, and how the application of such a heuristic might vary as a function of informational specificity. Experiment 1 demonstrates systematic and continuous spatial location memory biases as a function of associated affective information; right-handed individuals misremembered positively- and negatively-valenced locations as further right and left, respectively, relative to their original locations. Left-handed individuals did the opposite, and in general those with stronger right- or left-handedness showed greater spatial memory biases. Experiment 2 tested whether participants would show similar effects when studying a map with high visual specificity (i.e., zoomed in); they did not. Overall we support the hypothesis that handedness affects the coding of affective information, and better specify the scope and nature of body-specific effects on spatial memory. PMID:22386635

Brunyé, Tad T; Gardony, Aaron; Mahoney, Caroline R; Taylor, Holly A

2012-05-01

369

Spatial statistical models that use flow and stream distance  

Microsoft Academic Search

We develop spatial statistical models for stream networks that can estimate relationships between a response variable and\\u000a other covariates, make predictions at unsampled locations, and predict an average or total for a stream or a stream segment.\\u000a There have been very few attempts to develop valid spatial covariance models that incorporate flow, stream distance, or both.\\u000a The application of typical

Jay M. Ver Hoef; Erin Peterson; David Theobald

2006-01-01

370

USE OF THE SPATIAL KD-TREE IN COMPUTATIONAL PHYSICSAPPLICATIONS  

SciTech Connect

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.

Khamayseh, Ahmed K [ORNL; Hansen, Glen [Idaho National Laboratory (INL)

2007-01-01

371

Spatial grid services for adaptive spatial query optimization  

NASA Astrophysics Data System (ADS)

Spatial information sharing and integration has now become an important issue of Geographical Information Science (GIS). Web Service technologies provide a easy and standard way to share spatial resources over network, and grid technologies which aim at sharing resources such as data, storage, and computational powers can help the sharing go deeper. However, the dynamic characteristic of grid brings complexity to spatial query optimization which is more stressed in GIS domain because spatial operations are both CPU intensive and data intensive. To address this problem, a new grid framework is employed to provide standard spatial services which can also manage and report their state information to the coordinator which is responsible for distributed spatial query optimization.

Gao, Bingbo; Xie, Chuanjie; Sheng, Wentao

2008-10-01

372

Bipolar Fuzzy Spatial Information: Geometry, Morphology, Spatial Reasoning  

Microsoft Academic Search

\\u000a Spatial information may be endowed with a bipolarity component. Typical examples concern possible vs forbidden places for\\u000a an object in space, or “opposite” spatial relations such as “possibly to the right of an object and certainly not to its left”.\\u000a However, bipolarity has not been much exploited in the spatial domain yet. Moreover, imprecision has often to be taken into

Isabelle Bloch

373

Automated Verification of Spatial Resolution in Remotely Sensed Imagery  

NASA Technical Reports Server (NTRS)

Image spatial resolution characteristics can vary widely among sources. In the case of aerial-based imaging systems, the image spatial resolution characteristics can even vary between acquisitions. In these systems, aircraft altitude, speed, and sensor look angle all affect image spatial resolution. Image spatial resolution needs to be verified with estimators that include the ground sample distance (GSD), the modulation transfer function (MTF), and the relative edge response (RER), all of which are key components of image quality, along with signal-to-noise ratio (SNR) and dynamic range. Knowledge of spatial resolution parameters is important to determine if features of interest are distinguishable in imagery or associated products, and to develop image restoration algorithms. An automated Spatial Resolution Verification Tool (SRVT) was developed to rapidly determine the spatial resolution characteristics of remotely sensed aerial and satellite imagery. Most current methods for assessing spatial resolution characteristics of imagery rely on pre-deployed engineered targets and are performed only at selected times within preselected scenes. The SRVT addresses these insufficiencies by finding uniform, high-contrast edges from urban scenes and then using these edges to determine standard estimators of spatial resolution, such as the MTF and the RER. The SRVT was developed using the MATLAB programming language and environment. This automated software algorithm assesses every image in an acquired data set, using edges found within each image, and in many cases eliminating the need for dedicated edge targets. The SRVT automatically identifies high-contrast, uniform edges and calculates the MTF and RER of each image, and when possible, within sections of an image, so that the variation of spatial resolution characteristics across the image can be analyzed. The automated algorithm is capable of quickly verifying the spatial resolution quality of all images within a data set, enabling the appropriate use of those images in a number of applications.

Davis, Bruce; Ryan, Robert; Holekamp, Kara; Vaughn, Ronald

2011-01-01

374

A performance evaluation framework for association mining in spatial data  

PubMed Central

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

Wang, Qiang

2010-01-01

375

Spatial cognition and navigation  

NASA Technical Reports Server (NTRS)

An experiment that provides data for the development of a cognitive model of pilot flight navigation is described. The experiment characterizes navigational awareness as the mental alignment of two frames of reference: (1) the ego centered reference frame that is established by the forward view out of the cockpit and (2) the world centered reference frame that is established by the aircraft's location on a map. The data support a model involving at least two components: (1) the perceptual encoding of the navigational landmarks and (2) the mental rotation of the map's world reference frame into alignment with the ego centered reference frame. The quantitative relationships of these two factors are provided as possible inputs for a computational model of spatial cognition during flight navigation.

Aretz, Anthony J.

1989-01-01

376

A preliminary study of spatial cloud computing  

Microsoft Academic Search

After analyzing the fundamental disadvantages of grid computing, we propose the concept of spatial cloud computing, which consists of domain spatial data set, spatial cloud service, and spatial cloud. The dynamic structure of spatial cloud computing uses the lifecycle of spatial cloud lifecycle as a clue. We then discuss solutions for global virtualization, dynamic deployment, resource migration and granularity service

Qunwei Xue; Xiaolei Zhou; Juan Ma

2010-01-01

377

SPATIAL NEGLECT AND ATTENTION NETWORKS  

PubMed Central

Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere injuries to ventral fronto-parietal cortex. We propose that neglect reflects deficits in the coding of saliency, control of spatial attention, and representation within an egocentric frame of reference, in conjunction with non-spatial deficits of reorienting, target detection, and arousal/vigilance. In contrast to theories that link spatial neglect to structural damage of specific brain regions, we argue that neglect is better explained by the physiological dysfunction of distributed cortical networks. The ventral lesions in right parietal, temporal, and frontal cortex that cause neglect directly impair non-spatial functions and hypoactivate the right hemisphere, inducing abnormalities in task-evoked activity and functional connectivity of a dorsal frontal-parietal network that controls spatial attention. The anatomy and right hemisphere dominance of neglect follows from the anatomy and laterality of the ventral regions that interact with the dorsal attention network. PMID:21692662

Corbetta, Maurizio; Shulman, Gordon L.

2013-01-01

378

Spatial Aspects of Interspecific Competition  

NASA Technical Reports Server (NTRS)

Using several variants of a stochastic spatial model introduced by Silvertown et al., we investigate the effect of spatial distribution of individuals on the outcome of competition. First, we prove rigorously that if one species has a competitive advantage over each of the others, then eventually it takes over all the sites in the system. Second, we examine tradeoffs between competition and dispersal distance in a two-species system. Third, we consider a cyclic competitive relationship between three types. In this case, a nonspatial treatment leads to densities that follow neutrally stable cycles or even unstable spiral solutions, while a spatial model yields a stationary distribution with an interesting spatial structure.

Durrett, Rick; Levin, Simon

1998-01-01

379

ALGORITHM DEVELOPMENT FOR SPATIAL OPERATORS.  

USGS Publications Warehouse

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.

Claire, Robert W.

1984-01-01

380

Spatial Query for Planetary Data  

NASA Technical Reports Server (NTRS)

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.

Shams, Khawaja S.; Crockett, Thomas M.; Powell, Mark W.; Joswig, Joseph C.; Fox, Jason M.

2011-01-01

381

Predicting brain activity using a Bayesian spatial model.  

PubMed

Increasing the clinical applicability of functional neuroimaging technology is an emerging objective, e.g. for diagnostic and treatment purposes. We propose a novel Bayesian spatial hierarchical framework for predicting follow-up neural activity based on an individual's baseline functional neuroimaging data. Our approach attempts to overcome some shortcomings of the modeling methods used in other neuroimaging settings, by borrowing strength from the spatial correlations present in the data. Our proposed methodology is applicable to data from various imaging modalities including functional magnetic resonance imaging and positron emission tomography, and we provide an illustration here using positron emission tomography data from a study of Alzheimer's disease to predict disease progression. PMID:22743280

Derado, Gordana; Bowman, F Dubois; Zhang, Lijun

2013-08-01

382

Low Voltage Spatial Light Modulator  

SciTech Connect

This project studied the feasibility of a Low-Voltage actuator technology that promises to reduce the switched voltage requirements and linearize the response of spatial light modulators. We created computer models that demonstrate substantial advantages offered by this technology, and fabricated and tested those devices. SLMs are electro-optic devices for modulating the phase, amplitude or angle of light beams, laser or other. Applications for arrays of SLMs include turbulence correction for high-speed optical communications, imaging through distorting media, input devices for holographic memories, optical manipulation of DNA molecules, and optical computers. Devices based on micro electro-mechanical systems (MEMS) technology have recently become of special interest because of their potential for greatly improved performance at a much lower cost than piezoelectric or liquid crystal based devices. The new MEMS-based SLM devices could have important applications in high-speed optical communication and remote optical sensing, in support of DoD and DOE missions. Virtually all previously demonstrated MEMS SLMs are based on parallel-plate capacitors where an applied voltage causes a mirror attached to a suspended electrode to move towards a fixed electrode. They require relatively high voltages, typically on the order of 100 V, resulting in (1) large transistor sizes, available only from specialized foundries at significant cost and limiting the amount/sophistication of electronics under each SLM pixel, and (2) large power dissipation/area, resulting in a heat removal issue because of the optical precision required ({approx} 1/50-th of a wavelength). The actuator described in this process uses an advanced geometry that was invented at LLNL and is currently still proprietary. The new geometry allows the application of a bias voltage. This applied bias voltage results in a reduction of the required switched voltage and a linearization of the response curve. When this advanced actuator is coupled with non-linear springs, the response curve becomes even more linear. The response curve of the springs is tailored to produce an actuator with extremely linear displacement vs. voltage characteristics.

Papavasiliou, A

2003-02-19

383

Extracting spatial information: grounding, classifying and linking spatial expressions  

Microsoft Academic Search

This paper is concerned with the tagging of spatial expres- sions in German newspaper articles, assigning a meaning to the expression and classifying the usages of the spatial expression and linking the derived referent to an event de- scription. In our system, we implemented the activation of concepts in a very simple fashion, a concept is activated once (with a

Frank Schilder; Christopher Habel

384

One spatial map or many? Spatial coding of connected environments.  

PubMed

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 form separate spatial representations; this should incur an accuracy cost when inferring directions from one neighborhood to the other. Interestingly, our data instead suggest that people have a very strong tendency to form local representations, regardless of whether the neighborhoods were learned together or separately. Only when all visible distinctions between neighborhoods were removed did people behave as if they formed one integrated spatial representation. These data are broadly consistent with evidence from rodent hippocampal place cell recordings in connected boxes, and with hierarchical models of spatial coding. PMID:24364723

Han, Xue; Becker, Suzanna

2014-03-01

385

Spatial resolution considerations for urban hydrological modelling  

NASA Astrophysics Data System (ADS)

Hydrological model simulations can be applied to evaluate the performance of low impact development (LID) tools in urban areas. However, the assessment for large-scale urban areas remains a challenge due to the required high spatial resolution and limited availability of field measurements for model calibration. This study proposes a methodology to parameterize a hydrological model (SWMM) with sufficiently high spatial resolution and direct accessibility of model parameters for LID performance simulation applicable to a large-scale ungauged urban area. Based on calibrated high-resolution models for three small-scale study catchments (6-12 ha), we evaluated how constraints implied by large-scale urban modelling, such as data limitations, affect the model results. The high-resolution surface representation, resulting in subcatchments of uniform surface types, reduced the number of calibration parameters. Calibration conducted independently for all catchments yielded similar parameter values for same surface types in each study catchment. These results suggest the applicability of the parameter values calibrated for high resolution models to be regionalized to larger, ungauged urban areas. The accessibility of surface specific model parameters for LID simulation is then also retained. Conducted perturbations in spatial resolution through sewer network truncation showed that while the runoff volume was mostly unaffected by resolution perturbations, lower resolutions resulted in over-simulation of peak flows due to excessively rapid catchment response to storm events. Our results suggest that a hydrological model where parameter values are adopted from high-resolution models and that is developed based on a minimum conduit diameter of 300 mm provides good simulation performance and is applicable to large-scale urban areas with reasonable effort.

Krebs, G.; Kokkonen, T.; Valtanen, M.; Setälä, H.; Koivusalo, H.

2014-05-01

386

Advances in liquid crystal spatial light modulators  

NASA Astrophysics Data System (ADS)

Recent advances in our high-speed analog liquid crystal spatial light modulators (SLMs) will be presented. These advancements include higher pixel density, smaller pixel pitch, greatly improved optical efficiency, and higher speed operation. The new VLSI SLMs can utilize ferroelectric liquid crystal (FLC) or nematic liquid crystal (NLC) to achieve phase-only, amplitude-only and phase-amplitude-coupled modulation. These devices have applications in optical processing, optical storage, holographic display and beamsteering. Design criteria and experimental data will be presented.

Bauchert, Kipp A.; Serati, Steven A.; Furman, Alex

2002-03-01

387

Spatial and symbolic queries for 3D image data  

NASA Astrophysics Data System (ADS)

We present a query system for an object-oriented biomedical imaging database containing 3-D anatomical structures and their corresponding 2-D images. The graphical interface facilitates the formation of spatial queries, nonspatial or symbolic queries, and combined spatial/symbolic queries. A query editor is used for the creation and manipulation of 3-D query objects as volumes, surfaces, lines, and points. Symbolic predicates are formulated through a combination of text fields and multiple choice selections. Query results, which may include images, image contents, composite objects, graphics, and alphanumeric data, are displayed in multiple views. Objects returned by the query may be selected directly within the views for further inspection or modification, or for use as query objects in subsequent queries. Our image database query system provides visual feedback and manipulation of spatial query objects, multiple views of volume data, and the ability to combine spatial and symbolic queries. The system allows for incremental enhancement of existing objects and the addition of new objects and spatial relationships. The query system is designed for databases containing symbolic and spatial data. This paper discuses its application to data acquired in biomedical 3- D image reconstruction, but it is applicable to other areas such as CAD/CAM, geographical information systems, and computer vision.

Benson, Daniel C.; Zick, Gregory L.

1992-04-01

388

Auditory Spatial Layout  

NASA Technical Reports Server (NTRS)

All auditory sensory information is packaged in a pair of acoustical pressure waveforms, one at each ear. While there is obvious structure in these waveforms, that structure (temporal and spectral patterns) bears no simple relationship to the structure of the environmental objects that produced them. The properties of auditory objects and their layout in space must be derived completely from higher level processing of the peripheral input. This chapter begins with a discussion of the peculiarities of acoustical stimuli and how they are received by the human auditory system. A distinction is made between the ambient sound field and the effective stimulus to differentiate the perceptual distinctions among various simple classes of sound sources (ambient field) from the known perceptual consequences of the linear transformations of the sound wave from source to receiver (effective stimulus). Next, the definition of an auditory object is dealt with, specifically the question of how the various components of a sound stream become segregated into distinct auditory objects. The remainder of the chapter focuses on issues related to the spatial layout of auditory objects, both stationary and moving.

Wightman, Frederic L.; Jenison, Rick

1995-01-01

389

Spatial queries in sensor networks  

Microsoft Academic Search

Recent advances in low-power sensing devices coupled with the widespread availability of wireless ad-hoc networks have fueled the development of sensor networks. These are typically deployed over wide areas to gather data in the environment and monitor events of interest. The ability to run spatial queries is extremely useful for sensor networks. Spatial query execution has been extensively studied in

Amir Soheili; Vana Kalogeraki; Dimitrios Gunopulos

2005-01-01

390

How to measure spatial distances?  

E-print Network

The use of time--like geodesics to measure temporal distances is better justified than the use of space--like geodesics for a measurement of spatial distances. We give examples where a ''spatial distance'' cannot be appropriately determined by the length of a space--like geodesic.

Hans - Juergen Schmidt

1995-11-29

391

Spatial scaling of microbial biodiversity  

Microsoft Academic Search

A central goal in ecology is to understand the spatial scaling of biodiversity. Patterns in the spatial distribu- tion of organisms provide important clues about the underlying mechanisms that structure ecological com- munities and are central to setting conservation priori- ties. Although microorganisms comprise much of Earth's biodiversity, little is known about their biodiver- sity scaling relationships relative to that

Jessica Green; Brendan J. M. Bohannan

2006-01-01

392

The Spatial Logic of Parks  

Microsoft Academic Search

Urban parks are usually studied as discrete, green public open spaces. Less studied is how parks are geographically distributed from a ‘spatial logic’ point of view, i.e. how they ought to be geographically distributed across the urban landscape. This paper evaluates the degree to which normative principles about park distribution are in evidence from the standpoint of three spatial goals:

Emily Talen

2010-01-01

393

Spatial solitons in photorefractive media  

Microsoft Academic Search

It is shown that photorefractive media can support a new type of spatial soliton, in which the diffraction is balanced by the self-scattering (two-wave mixing) of the beam spatial frequency components. This photorefractive soliton possesses some unique properties, such as independence of the absolute light intensity, and can experience absorption (or gain) with no change in its transverse structure.

Mordechai Segev; Bruno Crosignani; Amnon Yariv; Baruch Fischer

1992-01-01

394

Wind Energy and Spatial Technology  

E-print Network

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

Schweik, Charles M.

395

The Space in Spatial Language  

ERIC Educational Resources Information Center

Projective spatial terms such as ''below'' specify the location of one object by indicating its spatial relation with respect to a reference object. These relations are defined via a reference frame that consists of a number of parameters (orientation, direction, origin, and distance) whose settings configure the space surrounding the reference…

Carlson, Laura A.; Van Deman, Shannon R.

2004-01-01

396

Rehearsal in spatial working memory  

Microsoft Academic Search

This article reports 3 experiments that tested a hypothesis regarding the nature of rehearsal in spatial working memory, one in which discrete shifts of spatial selective attention mediate the maintenance of location-specific representations. Experiment 1 demonstrated increases in visual processing efficiency for locations held in working memory, which suggested that attention was oriented toward these locations. Experiment 2 eliminated key

Edward Awh; John Jonides; Patricia A. Reuter-Lorenz

1998-01-01

397

Estimation in semiparametric spatial regression  

Microsoft Academic Search

Nonparametric methods have been very popular in the last couple of decades in time series and regression, but no such development has taken place for spatial models. A rather obvious reason for this is the curse of dimensionality. For spatial data on a grid evaluating the conditional mean given its closest neighbors requires a four-dimensional nonparametric regression. In this paper

Jiti Gao; Zudi Lu; Dag Tjøstheim

2006-01-01

398

Teaching Spatial Autocorrelation by Simulation.  

ERIC Educational Resources Information Center

Describes a computer simulation game that helps teach spatial autocorrelation, a fundamental geographic concept referring to the degree and kind of spatial patterning to be found in geographic data. Experiences with this simulation exercise at the State University of New York Buffalo are briefly summarized. (Author/BSR)

Griffith, Daniel A.

1987-01-01

399

Temporal focusing with spatially modulated excitation.  

PubMed

Temporal focusing of ultrashort pulses has been shown to enable wide-field depth-resolved two-photon fluorescence microscopy. In this process, an entire plane in the sample is selectively excited by introduction of geometrical dispersion to an ultrashort pulse. Many applications, such as multiphoton lithography, uncaging or region-of-interest imaging, require, however, illumination patterns which significantly differ from homogeneous excitation of an entire plane in the sample. Here we consider the effects of such spatial modulation of a temporally focused excitation pattern on both the generated excitation pattern and on its axial confinement. The transition in the axial response between line illumination and wide-field illumination is characterized both theoretically and experimentally. For 2D patterning, we show that in the case of amplitude-only modulation the axial response is generally similar to that of wide-field illumination, while for phase-and-amplitude modulation the axial response slightly deteriorates when the phase variation is rapid, a regime which is shown to be relevant to excitation by beams shaped using spatial light modulators. Finally, general guidelines for the use of spatially modulated temporally focused excitation are presented. PMID:19333304

Papagiakoumou, Eirini; de Sars, Vincent; Emiliani, Valentina; Oron, Dan

2009-03-30

400

Early Warning Signals of Ecological Transitions: Methods for Spatial Patterns  

PubMed Central

A number of ecosystems can exhibit abrupt shifts between alternative stable states. Because of their important ecological and economic consequences, recent research has focused on devising early warning signals for anticipating such abrupt ecological transitions. In particular, theoretical studies show that changes in spatial characteristics of the system could provide early warnings of approaching transitions. However, the empirical validation of these indicators lag behind their theoretical developments. Here, we summarize a range of currently available spatial early warning signals, suggest potential null models to interpret their trends, and apply them to three simulated spatial data sets of systems undergoing an abrupt transition. In addition to providing a step-by-step methodology for applying these signals to spatial data sets, we propose a statistical toolbox that may be used to help detect approaching transitions in a wide range of spatial data. We hope that our methodology together with the computer codes will stimulate the application and testing of spatial early warning signals on real spatial data. PMID:24658137

Brock, William A.; Carpenter, Stephen R.; Ellison, Aaron M.; Livina, Valerie N.; Seekell, David A.; Scheffer, Marten; van Nes, Egbert H.; Dakos, Vasilis

2014-01-01

401

Spatially explicit population models: Current forms and future uses  

SciTech Connect

Spatially explicit population models are becoming increasingly useful tools for population ecologists, conservation biologists, and land managers. Models are spatially explicit when they combine a population simulator with a landscaped map that describes the spatial distribution of landscape features. With this map, the locations of habitat patches, individuals, and other items of interest are explicitly incorporated into the model, and the effect of changing landscape features on population dynamics can be studied. In this paper we describe the structure of some spatially explicit models under development and provide examples of current and future research using these models. Spatially explicit models are important tools for investigating scale-related questions in population ecology, especially the response of organisms to habitat change occurring at a variety of spatial and temporal scales. Simulation models that incorporate real-world landscapes, as portrayed by landscape maps created with geographic information systems, are also proving to be crucial in the development of management strategies in response to regional land-use and other global change processes. Spatially explicit population models will increase our ability to accurately model complex landscapes, and therefore should improve both basic ecological knowledge of landscape phenomena and applications of landscape ecology to conservation and management. 58 refs., 1 fig.

Dunning, J.B. Jr.; Stewart, D.J. [Univ. of Georgia, Athens, GA (United States); Danielson, B.J. [Iowa State Univ., Ames, IA (United States); Noon, B.R. [US Forest Service, Arcata, CA (United States); Root, T.L. [Univ. of Michigan, Ann Arbor, MI (United States); Lamberson, R.H. [Humboldt State Univ., Arcata, CA (United States); Stevens, E.E. [Clemson Univ., SC (United States)

1995-02-01

402

Evaluation methods for association rules in spatial knowlegde base  

NASA Astrophysics Data System (ADS)

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.

Niu, X.; Ji, X.

2014-04-01

403

Spatial Uncertainty Model for Visual Features Using a Kinect™ Sensor  

PubMed Central

This study proposes a mathematical uncertainty model for the spatial measurement of visual features using Kinect™ sensors. This model can provide qualitative and quantitative analysis for the utilization of Kinect™ sensors as 3D perception sensors. In order to achieve this objective, we derived the propagation relationship of the uncertainties between the disparity image space and the real Cartesian space with the mapping function between the two spaces. Using this propagation relationship, we obtained the mathematical model for the covariance matrix of the measurement error, which represents the uncertainty for spatial position of visual features from Kinect™ sensors. In order to derive the quantitative model of spatial uncertainty for visual features, we estimated the covariance matrix in the disparity image space using collected visual feature data. Further, we computed the spatial uncertainty information by applying the covariance matrix in the disparity image space and the calibrated sensor parameters to the proposed mathematical model. This spatial uncertainty model was verified by comparing the uncertainty ellipsoids for spatial covariance matrices and the distribution of scattered matching visual features. We expect that this spatial uncertainty model and its analyses will be useful in various Kinect™ sensor applications. PMID:23012509

Park, Jae-Han; Shin, Yong-Deuk; Bae, Ji-Hun; Baeg, Moon-Hong

2012-01-01

404

Establishment of spatial pattern.  

PubMed

An overview and perspective are presented of mechanisms for the development of spatial pattern in animal embryos. It is intended both for new entrants to developmental biology and for specialists in other fields, with only a basic knowledge of animal life cycles being required. The first event of pattern formation is normally the localization of a cytoplasmic determinant in the egg, either during oogenesis or post-fertilization. Following cleavage to a multicellular stage, some cells contain the determinant and others do not. The determinant confers a specific developmental pathway on the cells that contain it, often making them the source of the first extracellular signal, or inducing factor. Inducing factors often form concentration gradients to which cells respond by up or downregulating genes at various concentration thresholds. This enables an initial situation consisting of two cell states (with or without the determinant) to generate a multistate pattern. Multiple rounds of gradient signaling, interspersed with phases of morphogenetic movements, can generate a complex pattern using a small number of signals and responding genes. Development proceeds in a hierarchical manner, with broad body subdivisions being specified initially, and becoming successively subdivided to give individual organs and tissues composed of multiple cell types in a characteristic arrangement. Double gradient models can account for embryonic regulation, whereby a similarly proportioned body pattern is formed following removal of material. Processes that are involved at the later stages include the formation of repeating structures by the combination of an oscillator with a gradient, and the formation of tissues with one cell type scattered in a background of another through a process called lateral inhibition. This set of processes make up a 'developmental toolkit' which can be deployed in various sequences and combinations to generate a very wide variety of structures and cell types. PMID:25081639

Slack, Jonathan

2014-01-01

405

Manakov spatial solitons  

NASA Astrophysics Data System (ADS)

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.

Kang, J. U.; Stegeman, G. I.; Aitchison, J. S.; Akhmediev, N.

1996-12-01

406

Adaptive Spatial Resampling for Seismic Inverse Modeling  

NASA Astrophysics Data System (ADS)

Inverse modeling is an essential process to integrate geophysical information in reservoir characterization. We propose a Markov chain Monte Carlo (McMC) workflow for sampling posteriors consistent with geology, well-logs, seismic data and rock-physics information. The workflow uses Direct Sampling (DS) as a multiple-point geostatistical method for generating realizations from the prior distribution, Adaptive Spatial Resampling (ASR) for forming a Markov chain, and Metropolis sampler for sampling from the posterior distribution conditioned to the geophysical data. To produce samples from the posterior probability density is a key issue in any inversion problems posed in a Bayesian framework. Sampling is a more general approach than optimization as it can assess important uncertainties and not just the most likely model. Rejection sampling is the only way to represent perfect posterior pdf. However, since it requires a large number of evaluations of forward model, it is inefficient and not suitable for reservoir modeling. Metropolis sampling is able to perform a reasonably equivalent sampling by forming a Markov chain. The spatial resampling algorithm perturbs realizations of a spatially dependent variable while preserving its spatial structure by conditioning to randomly selected subset points at every iteration. The method is used as a transition kernel to produce a Markov chain of geostatistical realizations. These realizations are then used in a forward seismic model to compute the predicted data which are compared to the observed data. Through this comparison for likelihood calculation we obtain a spatial error map at every iteration and the information can be used for generating the next model. Instead of randomly sampling a subset of points to condition the next realization, we adaptively sample important points with a probability proportional to the inverse of the residual error in the spatial error map. Thus the ASR accelerates to reach the posterior distribution and to find an optimal model consistent with the given data. Depending on the acceptation/rejection criterion in the Markov process, it is possible to obtain a chain of realizations aimed either at characterizing the posterior distribution with Metropolis sampling or at calibrating a single realization until an optimum is reached. Thus the algorithm can be tuned to work either as an optimizer or as a sampler. The validity and applicability of the proposed method, and sensitivity to different parameters is demonstrated by results for seismic lithofacies inversion on the synthetic Stanford VI data set.

Jeong, C.; Mukerji, T.; Mariethoz, G.

2011-12-01

407

Hadoop-GIS: A High Performance Spatial Data Warehousing System over MapReduce  

PubMed Central

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

Aji, Ablimit; Wang, Fusheng; Vo, Hoang; Lee, Rubao; Liu, Qiaoling; Zhang, Xiaodong; Saltz, Joel

2013-01-01

408

Hadoop-GIS: A High Performance Spatial Data Warehousing System over MapReduce.  

PubMed

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

Aji, Ablimit; Wang, Fusheng; Vo, Hoang; Lee, Rubao; Liu, Qiaoling; Zhang, Xiaodong; Saltz, Joel

2013-08-01

409

A spatial operator algebra for manipulator modeling and control  

NASA Technical Reports Server (NTRS)

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.

Rodriguez, G.; Kreutz, K.; Milman, M.

1988-01-01

410

Spatial-multiblock procedure for radiation heat transfer  

SciTech Connect

A spatial-multiblock procedure for radiation heat transfer is presented in this article. The proposed procedure is applicable to isothermal or nonisothermal, absorbing, emitting and scattering of transparent media with black or reflecting walls. Although not shown in this article, the procedure is also applicable to nongray conditions. The proposed procedure can be used with the discrete ordinates method and the finite volume method. The heat transfer rate, net radiation power and other full-range and half-range moments are conserved between spatial blocks by the proposed procedure. The utilities of the proposed procedure are shown using four sample problems. The solutions indicate that the multiblock procedure can reproduce the results of a single-block procedure even when very coarse spatial grids are used in the multiblock procedure.

Chai, J.C. [Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Mechanical Engineering; Moder, J.P. [NASA Lewis Research Center, Cleveland, OH (United States)

1996-12-31

411

Extinction and the spatial dynamics of biodiversity  

PubMed Central

The fossil record amply shows that the spatial fabric of extinction has profoundly shaped the biosphere; this spatial dimension provides a powerful context for integration of paleontological and neontological approaches. Mass extinctions evidently alter extinction selectivity, with many factors losing effectiveness except for a positive relation between survivorship and geographic range at the clade level (confirmed in reanalyses of end-Cretaceous extinction data). This relation probably also holds during “normal” times, but changes both slope and intercept with increasing extinction. The strong geographical component to clade dynamics can obscure causation in the extinction of a feature or a clade, owing to hitchhiking effects on geographic range, so that multifactorial analyses are needed. Some extinctions are spatially complex, and regional extinctions might either reset a diversity ceiling or create a diversification debt open to further diversification or invasion. Evolutionary recoveries also exhibit spatial dynamics, including regional differences in invasibilty, and expansion of clades from the tropics fuels at least some recoveries, as well as biodiversity dynamics during normal times. Incumbency effects apparently correlate more closely with extinction intensities than with standing diversities, so that regions with higher local and global extinctions are more subject to invasion; the latest Cenozoic temperate zones evidently received more invaders than the tropics or poles, but this dynamic could shift dramatically if tropical diversity is strongly depleted. The fossil record can provide valuable insights, and their application to present-day issues will be enhanced by partitioning past and present-day extinctions by driving mechanism rather than emphasizing intensity. PMID:18695229

Jablonski, David

2008-01-01

412

The emergence of spatial cyberinfrastructure  

PubMed Central

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

Wright, Dawn J.; Wang, Shaowen

2011-01-01

413

Modelling Spatial Relations by Generalized Proximity Matrices  

Microsoft Academic Search

One of the main challenges for the development of spatial information theory is the formalization of the concepts of space and spatial relations. Currently, most spatial data structures and spatial analytical methods used in GIS embody the notion of space as a set of absolute locations in a Cartesian coordinate system, thus failing to incorporate spatial relations which are dependent

Ana Paula Dutra De Aguiar; Gilberto Câmara; Antônio Miguel Vieira Monteiro; Ricardo Cartaxo Modesto De Souza

2003-01-01

414

The Detection of Clusters with Spatial Heterogeneity  

ERIC Educational Resources Information Center

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…

Zhang, Zuoyi

2011-01-01

415

THINKING SPATIALLY: CURRICULA K-16 AND PROFESSIONAL DEVELOPMENT FOR EDUCATORS  

Microsoft Academic Search

The study of spatial distributions and relationships has expanded to almost every discipline over the past 25 years. Geographic Information Science (GISc) has itself emerged as a new discipline. At North Carolina State University, seven colleges currently offer coursework in Geographic Information Systems (GIS), the application sub-discipline of GISc. Both graduate and undergraduate programs are offered. In 1996, the College

Harriett S. Stubbs; Hugh Devine; Rita Hagevik

416

Transformation of spatial and perturbation derivatives of travel time  

E-print Network

Transformation of spatial and perturbation derivatives of travel time at a general interface and perturbation parameters. We derive the explicit equations for transforming these travel­time derivatives Hamiltonian function and are applicable to the transformation of travel­time derivatives in both isotropic

Cerveny, Vlastislav

417

A Grid-based Spatial Association Mining Method  

Microsoft Academic Search

The grid is a distributed computing infrastructure that supports the sharing and coordinated use of various resources in virtual organizations. The grid can be used for compute intensive tasks and data intensive applications. Data mining algorithms are intensive compute and data, and spatial data are heterogeneous, multidimensional and stored at various places. Therefore, the grid can provide a computing and

Xiaohui Zhao; Yu Fang

2007-01-01

418

Active inverted stripline circular patch antennas for spatial power combining  

Microsoft Academic Search

An active antenna configuration is proposed for spatial-power-combining applications. The active patch antenna uses an inverted stripline topology to take advantage of several features. These features include avoiding drilling through the circuit substrate to insert the diode and the use of air within the resonant cavity to reduce loss. The inverted substrate serves as a radome for hermetic sealing. The

Julio A. Navarro; Lu Fan; Kai Chang

1993-01-01

419

Estimation of Complex Anatomical Joint Motions Using a Spatial Goniometer  

E-print Network

of human joints has numerous applications. The screw axis can be determined using optical motion capture of the instantaneous screw axis in human anatomical joints from the data given by a spatial mechanical goniometer. 1 systems with cameras and optical markers, or medical imaging modalities to mea- sure the movement of bones

Hayward, Vincent

420

HIGH-RESOLUTION SPATIAL MODELING OF DAILY WEATHER ELEMENTS FOR A CATCHMENT IN THE OREGON CASCADE MOUNTAINS, UNITED STATES  

EPA Science Inventory

High-quality, daily meteorological data at high spatial resolution are essential for a variety of hydrologic and ecological modeling applications that support environmental risk assessments and decision making. This paper describes the development, application, and assessment of ...

421

Spatial computation with gamma oscillations  

PubMed Central

Gamma oscillations in cortex have been extensively studied with relation to behavior in both humans and animal models; however, their computational role in the processing of behaviorally relevant signals is still not clear. One oft-overlooked characteristic of gamma oscillations is their spatial distribution over the cortical space and the computational consequences of such an organization. Here, we advance the proposal that the spatial organization of gamma oscillations is of major importance for their function. The interaction of specific spatial distributions of oscillations with the functional topography of cortex enables select amplification of neuronal signals, which supports perceptual and cognitive processing. PMID:25249950

Engelhard, Ben; Vaadia, Eilon

2014-01-01

422

Spatially resolved transcriptomics and beyond.  

PubMed

Considerable progress in sequencing technologies makes it now possible to study the genomic and transcriptomic landscape of single cells. However, to better understand the complexity of multicellular organisms, we must devise ways to perform high-throughput measurements while preserving spatial information about the tissue context or subcellular localization of analysed nucleic acids. In this Innovation article, we summarize pioneering technologies that enable spatially resolved transcriptomics and discuss how these methods have the potential to extend beyond transcriptomics to encompass spatially resolved genomics, proteomics and possibly other omic disciplines. PMID:25446315

Crosetto, Nicola; Bienko, Magda; van Oudenaarden, Alexander

2015-01-01

423

Routing Algorithm Exploits Spatial Relations  

NASA Technical Reports Server (NTRS)

A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in addition to transmission power levels and distances between the nodes. In contrast, most prior algorithms for discovering routes through ad hoc networks rely heavily on transmission power levels and utilize limited graph-topology techniques that do not involve consideration of the aforesaid spatial relationships. The present algorithm extracts the relevant spatial-relationship information by use of a construct denoted the relative-neighborhood graph (RNG).

Okino, Clayton; Jennings, Esther

2004-01-01

424

Plastic color mismatch causes identification using OLAP and data mining  

Microsoft Academic Search

Most companies have their data stored electronically. The appropriate processing of this data can quickly identify issues leading to process improvement and cost reduction. However, the manipulation of the data stored in the companies' repositories is not trivial for decision support. In this paper we propose the use of Excel spreadsheets for the detection of parameters that may cause the

Farid Bourennani; Ghaus M. Rizvi; Daniel Ross

2010-01-01

425

Hybrid OLTP&OLAP High Performance Database Reference Number  

E-print Network

, database systems were mainly used for online transaction process- ing. Typical examples of such transaction Patentallianz HYPER Database System we manage innovations #12;The two areas of online transaction processing processing (order entry, payment, delivery) system of a merchandising company. The benchmark refers

426

Semiblind Spatial ICA of fMRI Using Spatial Constraints  

PubMed Central

Independent component analysis (ICA) utilizing prior information, also called semiblind ICA, has demonstrated considerable promise in the analysis of functional magnetic resonance imaging (fMRI). So far, temporal information about fMRI has been used in temporal ICA or spatial ICA as additional constraints to improve estimation of task-related components. Considering that prior information about spatial patterns is also available, a semiblind spatial ICA algorithm utilizing the spatial information was proposed within the framework of constrained ICA with fixed-point learning. The proposed approach was first tested with synthetic fMRI-like data, and then was applied to real fMRI data from 11 subjects performing a visuomotor task. Three components of interest including two task-related components and the “default mode” component were automatically extracted, and atlas-defined masks were used as the spatial constraints. The default mode network, a set of regions that appear correlated in particular in the absence of tasks or external stimuli and is of increasing interest in fMRI studies, was found to be greatly improved when incorporating spatial prior information. Results from simulation and real fMRI data demonstrate that the proposed algorithm can improve ICA performance compared to a different semiblind ICA algorithm and a standard blind ICA algorithm. PMID:20017117

Lin, Qiu-Hua; Liu, Jingyu; Zheng, Yong-Rui; Liang, Hualou; Calhoun, Vince D.

2009-01-01

427

Spatial features register: toward standardization of spatial features  

USGS Publications Warehouse

As the need to share spatial data increases, more than agreement on a common format is needed to ensure that the data is meaningful to both the importer and the exporter. Effective data transfer also requires common definitions of spatial features. To achieve this, part 2 of the Spatial Data Transfer Standard (SDTS) provides a model for a spatial features data content specification and a glossary of features and attributes that fit this model. The model provides a foundation for standardizing spatial features. The glossary now contains only a limited subset of hydrographic and topographic features. For it to be useful, terms and definitions must be included for other categories, such as base cartographic, bathymetric, cadastral, cultural and demographic, geodetic, geologic, ground transportation, international boundaries, soils, vegetation, water, and wetlands, and the set of hydrographic and topographic features must be expanded. This paper will review the philosophy of the SDTS part 2 and the current plans for creating a national spatial features register as one mechanism for maintaining part 2.

Cascio, Janette

1994-01-01

428

Using spatial principles to optimize distributed computing for enabling the physical science discoveries  

PubMed Central

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

Yang, Chaowei; Wu, Huayi; Huang, Qunying; Li, Zhenlong; Li, Jing

2011-01-01

429

Spontaneous Brillouin-based distributed temperature fiber sensor with 35-cm spatial resolution  

Microsoft Academic Search

Certain distributed sensing applications require sub-meter spatial resolution accuracy, and there is interest as to whether the Brillouin linewidth ultimately limits the spatial resolution that can be achieved. We present a single-ended, spontaneous Brillouin-based distributed temperature fiber sensor with measurements operating with a spatial accuracy of 35 cm. The sensor consists of two