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1

Spatial Hierarchy and OLAP-Favored Search in Spatial Data Warehouse  

E-print Network

is geo-spatial related, either explicitly or implicitly [6]. With the advent of mobile computing intelligent systems to provide in- sight into business from the geo-spatial point of view. For example, when,longzh,yuxl,lying,yingch}@cn.ibm.com ABSTRACT Data warehouse and Online Analytical Processing(OLAP) play a key role in business intelligent

Song, Il-Yeol

2

A Generic Data Model and Query Language for Spatiotemporal OLAP Cube Analysis  

E-print Network

, the notion of SOLAP (Spatial OLAP) arouse, aimed at exploring spatial data in the same way as OLAP operates copies of all or part of this work for personal or classroom use is granted without fee provided of dimensions and fact tables. Modern organizations need to use OLAP analytical capabilities together

Libre de Bruxelles, Université

3

Efficient OLAP with UDFs  

Microsoft Academic Search

Since the early 1990s, On-Line Analytical Processing (OLAP) has been a well studied research topic that has focused on implementation outside the database, either with OLAP servers or entirely within the client computers. Our approach involves the computation and storage of OLAP cubes using User-Defined Functions (UDF) with a database management system. UDFs offer users a chance to write their

Zhibo Chen; Carlos Ordonez

2008-01-01

4

An interoperable XML encoding for the exchange of Spatial OLAP data cubes in SOA environments  

E-print Network

to traditional client-server plat- forms but also ubiquitous mobile computing environments. I. INTRODUCTION]. Emerging SOLAP applications, especially in mobile computing environments, have prompted the need Industrial Research Chair on Geospatial databases for Decision Support Université Laval Québec, Canada Phone

5

Advanced Visualization for OLAP Andreas S. Maniatis  

E-print Network

and the applicability of advanced visualization techniques in the presence of recent technological developments-Line Analytical Processing, Visualization 1. INTRODUCTION In the last years, On-Line Analytical Processing (OLAPAdvanced Visualization for OLAP Andreas S. Maniatis 1 Tel. +30-210-7721436 andreas

Song, Il-Yeol

6

Fast and dynamic OLAP exploration using UDFs  

Microsoft Academic Search

OLAP is a set of database exploratory techniques to efficiently retrieve multiple sets of aggregations from a large dataset. Generally, these techniques have either involved the use of an external OLAP server or required the dataset to be exported to a specialized OLAP tool for more efficient processing. In this work, we show that OLAP techniques can be performed within

Zhibo Chen; Carlos Ordonez; Carlos Garcia-alvarado

2009-01-01

7

Visualizing Multilevel Agency Data Using OLAP Technology: An Illustration and Lessons Learned  

Microsoft Academic Search

Various technologies exist that allow the visualization of data. One major set of technological innovations known as OLAP (Online Analytic Processing) were tested in three-year, exploratory research project to improve the decision making of child protective service staff related to federal CFSR (Child and Family Services Review) standards. The OLAP application developed, called DEMOS (Data Enhanced Management Online Support) contained

Dick Schoech; John D. Fluke; Randy Basham; Donald J. Baumann; Gary Cochran

2004-01-01

8

Expressing OLAP operators with the TAX XML algebra  

E-print Network

With the rise of XML as a standard for representing business data, XML data warehouses appear as suitable solutions for Web-based decision-support applications. In this context, it is necessary to allow OLAP analyses over XML data cubes (XOLAP). Thus, XQuery extensions are needed. To help define a formal framework and allow much-needed performance optimizations on analytical queries expressed in XQuery, having an algebra at one's disposal is desirable. However, XOLAP approaches and algebras from the literature still largely rely on the relational model and/or only feature a small number of OLAP operators. In opposition, we propose in this paper to express a broad set of OLAP operators with the TAX XML algebra.

Hachicha, Marouane; Darmont, Jérôme

2008-01-01

9

Exploration and Visualization of OLAP Cubes with Statistical Tests  

E-print Network

application of exploratory database analysis that is complementary to such approaches. In an OLAP database users have a wide spectrum of options to analyze a data set going from simple queries to building in the middle between uni- variate statistical analysis and complex statistical models. Our tool shows

Ordonez, Carlos

10

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

E-print Network

on XML documents dealing with the breast cancer researches domain. Keywords: OLAP; data warehouse; data are still not capable to analyze such data. In this paper, we associate OLAP and data mining to cope

Paris-Sud XI, Université de

11

OLAP with UDFs in digital libraries  

Microsoft Academic Search

Queries on digital libraries generally involve the retrieval of specific documents, but most techniques lack the ability to efficiently explore these collections. The integration of OLAP techniques with digital libraries allows users to navigate throughout these collections on multiple levels. In order to accomplish this, we propose the creation of OLAP networks, a complex data structure that contains summarized representations

Carlos Garcia-alvarado; Zhibo Chen; Carlos Ordonez

2009-01-01

12

Extending Complex AdHoc OLAP Theodore Johnson Damianos Chatziantoniou  

E-print Network

Extending Complex Ad­Hoc OLAP Theodore Johnson Damianos Chatziantoniou Database Research Dept. Dept literature on modeling and conceptualizing OLAP [14, 2, 21], research has been mainly focused on expression, Business Objects, Hyperion (Essbase), and Oracle Express, provide multidimensional data analysis and OLAP

Chatziantoniou, Damianos

13

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

14

Usability-based caching of query results in OLAP systems  

Microsoft Academic Search

In this paper we propose a new cache management scheme for online analytical processing (OLAP) systems based on the us- ability of query results in rewriting and processing other queries. For effective admission and replacement of OLAP query results, we consider the benefit of query results not only for recently issued queries but for the expected future queries of a

Chang-sup Park; Myoung-ho Kim; Yoon-joon Lee

2003-01-01

15

Fast and Dynamic OLAP Exploration Using UDFs University of Houston  

E-print Network

Fast and Dynamic OLAP Exploration Using UDFs Zhibo Chen University of Houston Dept. of Computer or the exporting of datasets, using standard SQL queries and UDFs. The main challenge of such approach is that SQL and UDFs are not as flexible as the C language to explore the OLAP lattice and therefore it is more

Ordonez, Carlos

16

Spatial aggregation: Language and applications  

SciTech Connect

Spatial aggregation is a framework for organizing computations around image-like, analogue representations of physical processes in data interpretation and control tasks. It conceptualizes common computational structures in a class of implemented problem solvers for difficult scientific and engineering problems. It comprises a mechanism, a language, and a programming style. The spatial aggregation mechanism transforms a numerical input field to successively higher-level descriptions by applying a small, identical set of operators to each layer given a metric, neighborhood relation and equivalence relation. This paper describes the spatial aggregation language and its applications. The spatial aggregation language provides two abstract data types - neighborhood graph and field - and a set of interface operators for constructing the transformations of the field, together with a library of component implementations from which a user can mix-and-match and specialize for a particular application. The language allows users to isolate and express important computational ideas in different problem domains while hiding low-level details. We illustrate the use of the language with examples ranging from trajectory grouping in dynamics interpretation to region growing in image analysis. Programs for these different task domains can be written in a modular, concise fashion in the spatial aggregation language.

Bailey-Kellogg, C.; Zhao, F. [Ohio State Univ., Columbus, OH (United States); Yip, K. [MIT Artificial Intelligence Lab., Cambridge, MA (United States)

1996-12-31

17

An efficient communication strategy for mobile agent based distributed spatial data mining application  

NASA Astrophysics Data System (ADS)

An efficient communication strategy is proposed in this paper, which aims to improve the response time and availability of mobile agent based distributed spatial data mining applications. When dealing with decomposed complex data mining tasks or On-Line Analytical Processing (OLAP), mobile agents authorized by the specified user need to coordinate and cooperate with each other by employing given communication method to fulfill the subtasks delegated to them. Agent interactive behavior, e.g. messages passing, intermediate results exchanging and final results merging, must happen after the specified path is determined by executing given routing selection algorithm. Most of algorithms exploited currently run in time that grows approximately quadratic with the size of the input nodes where mobile agents migrate between. In order to gain enhanced communication performance by reducing the execution time of the decision algorithm, we propose an approach to reduce the number of nodes involved in the computation. In practice, hosts in the system are reorganized into groups in terms of the bandwidth between adjacent nodes. Then, we find an optimal node for each group with high bandwidth and powerful computing resources, which is managed by an agent dispatched by agent home node. With that, the communication pattern can be implemented at a higher level of abstraction and contribute to improving the overall performance of mobile agent based distributed spatial data mining applications.

Han, Guodong; Wang, Jiazhen

2005-11-01

18

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

19

Web services-oriented architectures for mobile SOLAP applications  

Microsoft Academic Search

With the growing popularity of mobile computing and the empowerment of mobile devices by high end-users and decision-makers, the development of architectures based on web services for the deployment of mobile Spatial OLAP (SOLAP) applications is being perceived as a powerful solution. This paper deals with geospatial (web) Services-Oriented Architectures (SOA) for mobile processing of geo-decisional information. The paper first

Thierry Badard; Yvan Bédard; Frederic Hubert; Eveline Bernier; Etienne Dube

2008-01-01

20

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

21

Achieving Scalability in OLAP Materialized View Selection Thomas P. Nadeau  

E-print Network

and Computer Science University of Michigan Ann Arbor, Michigan nadeau@engin.umich.edu Toby J. Teorey Electrical Engineering and Computer Science University of Michigan Ann Arbor, Michigan teorey queries from large amounts of data residing in a data warehouse. 1.1 OLAP: The beast of burden Data

Song, Il-Yeol

22

An overview of data warehousing and OLAP technology  

Microsoft Academic Search

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

Surajit Chaudhuri; Umeshwar Dayal

1997-01-01

23

An OLAP-Enabled Software Environment for Modeling Patient Flow  

Microsoft Academic Search

On-line analytical processing (OLAP) tools use multidimensional views to provide quick access to information. They have become the de facto standard in the business world for analytical databases. In health care, care givers and managers could benefit from being able to perform interactive data exploration, ad-hoc analysis and possibly discover hidden trends and patterns in health data. However, health data

Christos Vasilakis; E. El-Darzi; P. Chountas

2006-01-01

24

View discovery in OLAP databases through statistical combinatorial optimization  

SciTech Connect

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

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

2009-01-01

25

Supporting OLAP Operations over Imperfectly Integrated Arizona State Univ.  

E-print Network

operations in OLAP are also useful to understand data in more general cases such as shopping decisions in e-commerce. A typical e-commerce site provides a search result of items (e.g., auction) divided into hierarchical cate consider ways to minimize un-classification in the process. We introduce a cost model which captures

Candan, Selçuk

26

Hierarchical clustering for OLAP: the CUBE File approach  

Microsoft Academic Search

This paper deals with the problem of physical clustering of multidimensional data that are organized in hierarchies on disk\\u000a in a hierarchy-preserving manner. This is called hierarchical clustering. A typical case, where hierarchical clustering is necessary for reducing I\\/Os during query evaluation, is the most detailed\\u000a data of an OLAP cube. The presence of hierarchies in the multidimensional space results

Nikos Karayannidis; Timos K. Sellis

2008-01-01

27

Coarse Grained Parallel OnLine Analytical Processing (OLAP) For Data Mining  

E-print Network

Coarse Grained Parallel On­Line Analytical Processing (OLAP) For Data Mining Frank Dehne 1 , Todd­ puting model (CGM) to on­line analytical processing (OLAP) for data mining. We present a general been tremendous growth in the data warehous­ ing market. Despite the sophistication and maturity

Rau-Chaplin, Andrew

28

MINING FUZZY SPATIAL CONFIGURATION RULES: METHODS AND APPLICATIONS  

Microsoft Academic Search

In view of the related research results of GIS and spatial analysis and according to the requirement of fuzzy spatial queries, this paper presents a spatial configuration rule mining and feature extracting method based on spatial association rule mining and fuzzy spatial relation reasoning. We detailed introduce the principle and method as well as application examples. A six mining steps

Rongqin Lan; Wenzhong Shi; Xiaomei Yang; Guangyuan Lin

29

Adaptive Virtual Partitioning for OLAP Query Processing in a Database Cluster  

Microsoft Academic Search

OLAP queries are typically heavy-weight and ad-hoc th us requiring high storage capacity and processing power. In this paper, we address this problem using a database cluster which we see as a cost-effectiv e alternative to a tightly-coupled multiprocessor. We propose a solution to efficient OLAP query processin g using a simple data parallel processing technique c alled adaptive virtual

Alexandre A. B. Lima; Marta Mattoso; Patrick Valduriez

2004-01-01

30

Spatially Variant Morphological Image Processing: Theory and Applications  

E-print Network

Spatially Variant Morphological Image Processing: Theory and Applications N. Bouaynaya and D under Euclidean translations. An interest in the extension of mathematical morphology to spatially-variant (image) processing. This paper presents a general theory of spatially-variant mathematical morphology

Bouaynaya, Nidhal

31

Accounting for the spatial rainfall variability in urban modelling applications.  

PubMed

In hydrological and hydrodynamic modelling of urban catchments, the spatial variability of rainfall is often neglected. This spatial variability encloses two aspects: (1) the spatial variability of the statistical properties of rainfall, and (2) the non-uniform spatial distribution of rainfall over the modelled catchments. In an ongoing research project for the Ministry of the Flemish Community (Belgium), the influence of this spatial rainfall variability on the results of modelling applications is studied. At the same time, most efficient methods to reduce this influence are determined. The results of the research can be applied directly in Flanders. They consist of a combination of unified IDF-relationships, spatial correction factors (generally applicable formulas), a stochastic simulation model for spatial rainfall (software) and a methodology for improving the spatial correction factors in a case-specific way by performing simulations with the model. PMID:11888171

Willems, P; Berlamont, J

2002-01-01

32

Bayesian multivariate spatial models and their applications  

E-print Network

model is generalized for several multivariate cases. A general theorem for each case is provided to ensure that the posterior distribution is proper under improper and ?at prior. The performance of various multivariate spatial models is compared...

Song, Joon Jin

2004-11-15

33

Technological Applications to Support Children's Development of Spatial Awareness  

ERIC Educational Resources Information Center

This article presents methods and theory behind promoting children's spatial awareness through representing 3D reality in 2D cyberspace. Spatial awareness in children is an often neglected aspect in early education. However, applications such as GPS and 3D modeling programs can be used to offer children rich experiences that allow children to…

Matthews, David; Geist, Eugene A.

2002-01-01

34

Spatial Decision Tree-Application to Traffic Risk Analysis  

Microsoft Academic Search

Spatial data mining fulfills real needs of many geomatic applications. It allows taking advantage of the growing availability of geographically referenced data and their potential richness. This includes the risk analysis linked to a territory such as epidemic risk or traffic accident risk in the road network. This work deals with the method of decision tree for spatial data classification.

Karine Zeitouni; Nadjim Chelghoum

2001-01-01

35

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

NASA Astrophysics Data System (ADS)

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

Tsutsumi, Morito; Seya, Hajime

2009-12-01

36

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

37

Evaluating Statistical Tests on OLAP Cubes to Compare Degree of Disease  

E-print Network

1 Evaluating Statistical Tests on OLAP Cubes to Compare Degree of Disease Carlos Ordonez, Zhibo Chen University of Houston Houston, TX 77204, USA Abstract--Statistical tests represent an important. In this work, we propose to compute parametric statistical tests treating patient records as elements

Ordonez, Carlos

38

Technological Applications to Support Children's Development of Spatial Awareness  

Microsoft Academic Search

This article presents methods and theory behind promoting children's spatial awareness through representing 3D reality in 2D cyberspace. Spatial awareness in children is an often neglected aspect in early education. However, applications such as GPS and 3D modeling programs can be used to offer children rich experiences that allow children to interact and experience 2D and 3D space in a

David Matthews; Eugene A. Geist

2002-01-01

39

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

40

Construction and application of a spatial hurricane climatology  

NASA Astrophysics Data System (ADS)

The tracking of hurricanes, largely controlled by the organization of the presiding pressure systems, determines whether or not any given hurricane will strike a coastline. Some of the climatic influences, such as the North Atlantic Oscillation, show annual- or decadal-variability. This means that particular locations will have typical hurricane tracks that may vary with the climate. Therefore, it makes physical sense to summarize large sets of hurricane tracks by creating an average track. A hurricane climatology describes the typical hurricane to affect a location. This dissertation proposes expanding the hurricane climatology by adding a spatial dimension in the form of an average track. This is referred to as a spatial hurricane climatology. Since a hurricane track is a polyline, the construction of a spatial hurricane climatology requires averaging spatial polyline data. The technique introduced in this dissertation uses distance maps to average a set of polylines. Three applications of spatial hurricane climatologies are also detailed in this work. First they are used to construct historical hurricane chronologies. This has the possibility of providing an additional 150 years of hurricane data, providing a glimpse into hurricanes prior to the American industrial revolution. The second application is a risk analysis of local-scale hurricane winds. The technique uses statistics of past hurricanes and places them in a deterministic model. This can be performed for any coastal area, and provides wind gusts and economic loss estimations for a once-in-100-year event. Because the statistics are easy to manipulate, this allows for simple analysis of the affects of climate change. This is done as the final application of the technique. These are only a few examples of the uses of spatial hurricane climatologies, and the ideas presented in this research provide a basis for future studies on spatial hurricane patterns, as well as the analysis of spatial polyline data in general.

Scheitlin, Kelsey

41

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

42

Management model application at nested spatial levels in Mediterranean Basins  

NASA Astrophysics Data System (ADS)

In the EU Water Framework Directive (WFD) implementation processes, hydrological and water quality models can be powerful tools that allow to design and test alternative management strategies, as well as judging their general feasibility and acceptance. Although in recent decades several models have been developed, their use in Mediterranean basins, where rivers have a temporary character, is quite complex and there is limited information in literature which can facilitate model applications and result evaluations in this region. The high spatial variability which characterizes rainfall events, soil hydrological properties and land uses of Mediterranean basin makes more difficult to simulate hydrological and water quality in this region than in other Countries. This variability also has several implications in modeling simulations results especially when simulations at different spatial scale are needed for watershed management purpose. It is well known that environmental processes operating at different spatial scale determine diverse impacts on water quality status (hydrological, chemical, ecological). Hence, the development of management strategies have to include both large scale (watershed) and local spatial scales approaches (e.g. stream reach). This paper presents the results of a study which analyzes how the spatial scale affects the results of hydrologic process and water quality of model simulations in a Mediterranean watershed. Several aspects involved in modeling hydrological and water quality processes at different spatial scale for river basin management are investigated including model data requirements, data availability, model results and uncertainty. A hydrologic and water quality model (SWAT) was used to simulate hydrologic processes and water quality at different spatial scales in the Candelaro river basin (Puglia, S-E Italy) and to design management strategies to reach as possible WFD goals. When studying a basin to assess its current status and anthropogenic pressures acting on it to define management policies, three spatial levels must be taken into account: the basin, sub-basin and reach level. The common experience showed that different issues can be properly assessed and handled at these three levels. Furthermore different difficulties and problems affect modeling at the same spatial levels. The basin scale is the geographical unit (as required by the WFD) in which coherent management policy must be designed and a Program of Measures must be implemented. At this spatial level a comprehensive understanding of processes acting in the basin area is synthesized (i.e. nutrient loads delivered to the sea). In Mediterranean region land use is commonly very fragmented and also because of complex geomorphology the use of remote sensing can be not easy or sufficient to derive reliable land use maps of agricultural areas. The sub-basin level (<100 km2) is the most suited to gather information on land and water resources use, agricultural practices and pressures by using direct surveys and local knowledge. At this spatial resolution soil and rainfall variability are somehow "averaged" and the model simulation tend to attenuate the complex, local patterns of runoff generation. As a results, an acceptable flow modeling is possible, being this a common issue in the Mediterranean areas where intermittency of rivers is the rule. The reach level is the spatial unit in which physical and ecological processes can be assessed. It is sufficiently narrow to observe peculiarities of geomorphology and water works (i.e. check dams, water abstractions) that can greatly interact with natural flow. At this level modeling often fails in simulating actual streamflow. At local scale field observations can help also to overcome recorded flow measurements inconsistencies, due to the difficulties in metering low flows (i.e. rivulets can detour and skip flow meters) that often lead to underestimate extreme low flow. The modeling of Mediterranean river basins is then rather a challenge and the understanding of potenti

Lo Porto, Antonio; De Girolamo, Anna Maria; Froebrich, Jochen

2014-05-01

43

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.-Y. Cynthia Lin University of California at Davis ­ USA Abstract. This paper uses spatial econometrics

Lin, C.-Y. Cynthia

44

372 IEEE TRANSACTIONS ON MULTIMEDIA, VOL. 11, NO. 3, APRIL 2009 iOLAP: A Framework for Analyzing the Internet,  

E-print Network

showed that our framework is able to provide deep insights jointed obtained from various dimensions, personalization, textual and multimedia data, web mining. I. INTRODUCTION A. Internet OLAP THE advent of online, sentiments, wisdom of crowds, etc. Such information is more valuable for the purpose of business intel

Zhang, Yi

45

Photorefractive spatial solitons, induced waveguides, and their applications  

NASA Astrophysics Data System (ADS)

This thesis presents theoretical and experimental research on optical spatial solitons and their waveguides. Different applications are proposed and demonstrated. It is shown for the first time that, soliton-induced waveguides can be used to build optical directional couplers. By generating two mutually incoherent parallel solitons at close proximity, efficient energy transfer of a probe beam from one induced waveguide to another is observed, and the efficiency is studied as a function of the distance between the two solitons. Two important applications of soliton-induced waveguides in frequency conversion are proposed and demonstrated: second harmonic generation and optical parametric oscillation. It is shown that with soliton-induced waveguides, the conversion efficiency of second harmonic generation can be greatly improved, and the pump threshold of optical parametric oscillators can be noticeably reduced. In addition to enhanced efficiency conversion, soliton-induced waveguides offer more advantages, such as tunability. Angle tuning and electrical tuning methods are investigated. It is also proposed that optical gratings can be built by launching two coherent counter-propagating spatial solitons. The study of the mutual self-trapping of such two solitons leads to a new concept of vector solitons-counter-propagating solitons. The theories and experimental results of this new vector soliton are presented, and the reflection from the grating is observed. Two other topics of vector solitons are also investigated. (1) Theoretical and experimental results show that the collision between two vector solitons can offer a feather that is not existent with scalar solitons: energy exchange. (2) (2+1)D multimode solitons are demonstrated for the first time.

Lan, Song

46

Towards OLAP Security Design Survey and Research Issues  

E-print Network

, this data is usually very valuable and sensitive. The concept of secu- rity is very broad (covering ethical. Application A2 deals with the drinking water distribution and consumption in the Western Bohemian region close

Song, Il-Yeol

47

End User Development for OLAP - A Scenario from Food Industry  

Microsoft Academic Search

\\u000a Database applications allow the analysis of complex and large data sets. Such applications typically offer a lot of analysis\\u000a functions to reveal all kinds of relations inside the data. Nevertheless end-users quite often face situations where they\\u000a require viewing certain data or relations that is not easily provided by their existing analysis software. To overcome these\\u000a situations they need means

Mario Gleichmann; Thomas Hasart; Ilvio Bruder; Andreas Wolff

2010-01-01

48

Zero-inflated models with application to spatial count data  

Microsoft Academic Search

Count data arises in many contexts. Here our concern is with spatial count data which exhibit an excessive number of zeros. Using the class of zero-inflated count models provides a flexible way to address this problem. Available covariate information suggests formulation of such modeling within a regression framework. We employ zero-inflated Poisson regression models. Spatial association is introduced through suitable

Deepak K. Agarwal; Alan E. Gelfand; Steven Citron-Pousty

2002-01-01

49

Spatial point pattern analysis and its application in geographical epidemiology  

Microsoft Academic Search

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

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

1996-01-01

50

Connecting mobility services and spatial territory typology: an application to a former coal mining area in France  

E-print Network

Connecting mobility services and spatial territory typology: an application to a former coal mining 1 CONNECTING MOBILITY SERVICES AND SPATIAL TERRITORY TYPOLOGY: AN APPLICATION TO A FORMER COAL)" #12;Connecting mobility services and spatial territory typology: an application to a former coal

Boyer, Edmond

51

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

52

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

53

A method of qualitative spatial envisionment with applications to planar mechanism configuration modeling and planning  

Microsoft Academic Search

This paper describes a method for qualitatively representing and reasoning about spatial configurations ofplanar mechanisms. The method has direct relevance to, and implications for,computer-aided mechanism design androbotics. In particular, it can be used to solve spatial configuration problems where exact geometric knowledge is not available, and to provide guidance for the application of quantitative configuration modeling and planning methods. In

Jiming Liu

1996-01-01

54

Bayesian spatial transformation models with applications in neuroimaging data.  

PubMed

The aim of this article 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. The proposed STM 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

2013-12-01

55

Determining transit impact on Seoul office rent and land value: an application of spatial econometrics  

E-print Network

DETERMINING TRANSIT IMPACT ON SEOUL OFFICE RENT AND LAND VALUE: AN APPLICATION OF SPATIAL ECONOMETRICS A Dissertation by JIN KIM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2004 Major Subject: Urban and Regional Science DETERMINING TRANSIT IMPACT ON SEOUL OFFICE RENT AND LAND VALUE: AN APPLICATION OF SPATIAL ECONOMETRICS A Dissertation by JIN KIM...

Kim, Jin

2005-02-17

56

Opportunities to Develop an Interagency Spatial Hierarchy for ESD Applications  

E-print Network

Outline Brief history of ecological classification and mapping What is a spatial hierarchy ­ concepts types based on combinations of tree species and ground-flora communities. Brief Background of Ecosystem interactions of climate, vegetation, parent materials, relief, and time. In 1893, E.W. Hilgard extended

57

Bayesian spatial models: Applications for tropospheric ozone data  

NASA Astrophysics Data System (ADS)

This research addresses issues pertaining to trend estimation in tropospheric ozone data as well as estimation of the spatial correlation structure of these data collected at multiple monitoring sites. Assessing long-term trends in tropospheric ozone data is imperative because of its adverse effect on human health and on agricultural crops. Moreover, we also estimate the spatial correlation structure of such data, which is essential for spatial trend estimation, spatial prediction and for redesigning an existing network of stations. The U.S. Environmental Protection Agency's (EPA) National Ambient Air Quality Standard for ozone is stated in terms of exceedances of a specified threshold level. Therefore, the EPA is concerned with the long-term trend in the probability of an exceedance. In the first part of my dissertation we build a multivariate nonparametric probit regression model estimated within a hierarchical Bayes framework to model the probability of an exceedance after allowing for the effects of changing meteorological conditions. There are three advantages to using this model. First, the trends estimated at each site in a region can be separated into a city-wide component that is common to all sites, and a site-specific component that is unique to the individual site. Second, the hierarchical Bayes framework allows for the ``borrowing of strength'' from data collected at other monitoring sites to increase the information available regarding the trend at each individual site. Third, the nonparametric model does not require the a priori specification of the functional forms relating the probability of an exceedance to the meteorological variables. Ozone data from four Houston monitoring sites for the period 1981-1997 are analyzed. In the second part we provide a penalized likelihood approach to estimating the spatial correlation structure when the assumptions of stationarity and isotropy are violated. The spatial correlation structure under these circumstances is estimated by deforming the geographic space in which the monitoring sites exist into a space called the deformed space where the assumptions of stationarity and isotropy are valid. Using the locations of the monitoring sites in the deformed space the spatial correlation structure is then estimated. The methodology is very simple to implement and is illustrated using a simulation and a dataset consisting of tropospheric ozone measurements collected at 21 monitoring locations in the Chicago area.

Menezes, Kim Anne

1999-12-01

58

Spatial noise in microdisplays for near-to-eye applications  

NASA Astrophysics Data System (ADS)

Spatial noise in imaging systems has been characterized and its impact on image quality metrics has been addressed primarily with respect to the introduction of this noise at the sensor component. However, sensor fixed pattern noise is not the only source of fixed pattern noise in an imaging system. Display fixed pattern noise cannot be easily mitigated in processing and, therefore, must be addressed. In this paper, a thorough examination of the amount and the effect of display fixed pattern noise is presented. The specific manifestation of display fixed pattern noise is dependent upon the display technology. Utilizing a calibrated camera, US Army RDECOM CERDEC NVESD has developed a microdisplay (?display) spatial noise data collection capability. Noise and signal power spectra were used to characterize the display signal to noise ratio (SNR) as a function of spatial frequency analogous to the minimum resolvable temperature difference (MRTD) of a thermal sensor. The goal of this study is to establish a measurement technique to characterize ?display limiting performance to assist in proper imaging system specification.

Hastings, Arthur R., Jr.; Draper, Russell S.; Wood, Michael V.; Fellowes, David A.

2011-06-01

59

Optimizing spatial filters with kernel methods for BCI applications  

NASA Astrophysics Data System (ADS)

Brain Computer Interface (BCI) is a communication or control system in which the user's messages or commands do not depend on the brain's normal output channels. The key step of BCI technology is to find a reliable method to detect the particular brain signals, such as the alpha, beta and mu components in EEG/ECOG trials, and then translate it into usable control signals. In this paper, our objective is to introduce a novel approach that is able to extract the discriminative pattern from the non-stationary EEG signals based on the common spatial patterns(CSP) analysis combined with kernel methods. The basic idea of our Kernel CSP method is performing a nonlinear form of CSP by the use of kernel methods that can efficiently compute the common and distinct components in high dimensional feature spaces related to input space by some nonlinear map. The algorithm described here is tested off-line with dataset I from the BCI Competition 2005. Our experiments show that the spatial filters employed with kernel CSP can effectively extract discriminatory information from single-trial EGOG recorded during imagined movements. The high recognition of linear discriminative rates and computational simplicity of "Kernel Trick" make it a promising method for BCI systems.

Zhang, Jiacai; Tang, Jianjun; Yao, Li

2007-11-01

60

Yield response of potato to spatially patterned nitrogen application  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

61

Spatial Optimization of Fertilizer Application by Centrifugal Spreading  

Microsoft Academic Search

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

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

62

Modeling and querying uncertain spatial information for situational awareness applications  

Microsoft Academic Search

Situational awareness (SA) applications monitor the real world and the entities therein to support tasks such as rapid decision-making, reasoning, and analysis. Raw input about unfolding events may arrive from variety of sources in the form of sensor data, video streams, human observations, and so on, from which events of interest are extracted. Location is one of the most important

Dmitri V. Kalashnikov; Yiming Ma; Sharad Mehrotra; Ramaswamy Hariharan; Carter Butts

2006-01-01

63

Toward Managing Uncertain Spatial Information for Situational Awareness Applications  

Microsoft Academic Search

Situational awareness (SA) applications monitor the real world and the entities therein to support tasks such as rapid decision making, reasoning, and analysis. Raw input about unfolding events may arrive from variety of sources in the form of sensor data, video streams, human observations, and so on, from which events of interest are extracted. Location is one of the most

Yiming Ma; Dmitri V. Kalashnikov; Sharad Mehrotra

2008-01-01

64

SOIL PHOSPHOROUS SPATIAL DISTRIBUTION IN PASTURES RECEIVING POULTRY LITTER APPLICATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Environmentally-based P management strategies could be improved by delineating management zones incorporating the effects of landscape position on soil morphology, hydrology, and soil P distribution. Three farm pasture sites in SW Missouri receiving long-term poultry litter applications were sampled...

65

Connecting mobility services and spatial territory typology: an application to a former coal mining area in France  

E-print Network

Connecting mobility services and spatial territory typology: an application to a former coal mining 1 CONNECTING MOBILITY SERVICES AND SPATIAL TERRITORY TYPOLOGY: AN APPLICATION TO A FORMER COAL: an application to a former coal mining area in France MAHIEUX, Aurélie; HEDDEBAUT, Odile 13th WCTR, July 15

Boyer, Edmond

66

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

NASA Astrophysics Data System (ADS)

A spatially variable rate herbicide application system was developed and a site-specific evaluation of its field performance and accuracy was conducted. The system was capable of automatically changing on-the-go the application rate of active ingredients (AI) to meet the requirements of current sprayer field location. A 4.2 ha field was sampled on an 18.3 m grid for soil texture and percent organic matter (%OM). The soil texture ranged from sandy loam to clay, while the %OM ranged from 0.98 to 2.73 percent. For the preemergence herbicide selected, a herbicide management table was used to determine the appropriate AI application rate for each area of the field depending on spatial variation of field parameter data (soil texture and %OM). For the sampled field, the AI application rate ranged from 3510 mL/ha to 5260 mL/ha. A geographical information system (GIS) software was utilized to develop a georeferenced map (management map) of field application rates. A direct nozzle injection field sprayer was equipped with a real-time differentially corrected global positioning system (DGPS). A control program was developed to retrieve the desired application rate from the GIS map utilizing position data (latitude and longitude) supplied by the DGPS system. The retrieved application rate was sent, in a voltage format, to a 21X datalogger which was used to change on-the-go the AI flow rate to correspond with the desired application rate at a specific sprayer ground speed and field position. Results revealed that the DGPS system maintained, on the average, an accuracy of one meter. However, a distance error of location determination produced by the DGPS system reached 30.84 m with a correction message age of 98 seconds. For the four application rates used in the study, the highest average application rate error (average difference between desired and calculated application rates) and CV values were 2.0 percent and 0.07 percent, respectively for the analyzed samples. The maximum application rate error was 14 percent for 96 percent of the field data points (96 percent of the time). These results showed that the control system was accurate in producing the desired application rate. On the average, the greatest reaction time of the system was 2.2 seconds. The spatial analysis showed that most application rate errors occurred near transition zones. These analysis also revealed that the contour lines of the calculated application rate maps followed the same pattern and coincide with the management map contour lines. The developed spatially variable rate herbicide application system was found to accurately reproduce the application rate management map in a repeatable fashion.

Al-Gaadi, Khalid Ali

1998-12-01

67

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

PubMed

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

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

2015-04-01

68

Large sample properties of the matrix exponential spatial specification with an application to FDI  

E-print Network

Large sample properties of the matrix exponential spatial specification with an application to FDI,1) is applied to Belgium's outward FDI data and we observe that the dominant motivation of Belgium's outward FDI, Heteroskedasticity, Delta method, FDI JEL Classification: C12, C13, C21, F14, F21 Email addresses: nicolas

Paris-Sud XI, Université de

69

Design of Control Policies for Spatially Inhomogeneous Robot Swarms with Application to Commercial Pollination  

E-print Network

Design of Control Policies for Spatially Inhomogeneous Robot Swarms with Application to Commercial inhomogeneous robotic swarm that emulates a system of chemically reacting molecules. Our ap- proach is based blueberry pollination by a swarm of robotic bees and using the macroscopic model to select control policies

Napp, Nils

70

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

E-print Network

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

Sydney, University of

71

Micro/Macro-Economic and Spatial Individual Risk Models for Catastrophe Insurance Applications  

E-print Network

, earthquakes, winter storms, floods, etc. frequently produce thousands of correlated claims, sometimesMicro/Macro-Economic and Spatial Individual Risk Models for Catastrophe Insurance Applications H versions of the individual risk model that include the possibility of catastrophes. Even though the models

Duchesne, Thierry

72

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

73

OLAP on Search Logs: An Infrastructure Supporting Data-Driven Applications in Search Engines  

E-print Network

are not made or distributed for profit or commercial advantage and that copies bear this notice and the full profitable for the search engine. For example, by examining the queries frequently asked by users after the query "KDD 2009", a search engine can sug- gest queries such as "Paris hotel" which may improve users

Pei, Jian

74

Spatial data technologies for environmental management within the Department of Energy (DOE): Issues and applications  

SciTech Connect

The US Department of Energy (DOE) manages the Nuclear Weapons Complex, a national network of research laboratories and production facilities. For 45 years, the Complex has supplied the US with nuclear materials for weapons and fuel. However, with the collapse of the Soviet Union and an accumulated excess of nuclear materials, production has dramatically decreased and the DOE is faced with the challenge of processing wastes and remediating environmental contamination at Complex facilities. Spatial data technologies, particularly remote sensing systems, the Global Positioning System (GPS), and Geographic Information Systems (GIS), can aid in detecting, characterizing, and monitoring hazardous and radioactive wastes. This paper discusses the role of spatial data technologies in DOE`s environmental mission and gives examples of their current application within the Complex. Specific barriers inhibiting the use of the technologies within the DOE are identified and proactive measures to address them are recommended. A principal recommendation is the development of a spatially explicit model for environmental data.

Albers, B.J. [BDM Federal, Inc., Gaithersburg, MD (United States). Environmental Technologies Div.; Nalezny, C.L.; Purdy, C.B. [Dept. of Energy, Washington, DC (United States); Singhroy, V.H. [Canada Center for Remote Sensing, Ottawa, Ontario (Canada)

1996-12-31

75

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

76

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

77

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

78

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

79

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

Microsoft Academic Search

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

V. Herrera; J. Borcosque

80

Metropolitan Governance and ICT Applications: spatial planning and entrepreneurship policies in the Greater Area of Thessaloniki  

Microsoft Academic Search

The paper approaches e-Governance at the Thessaloniki metropolitan area by investigating both the existence and the utilization of technological applications available to the public and\\/or private agencies in the policy fields of spatial planning and entrepreneurship. The core hypothesis of this approach is that e-Governance can increase the synergy between policies at the metropolitan level. Especially in the Thessaloniki metropolitan

Anastasia Tasopoulou; Christina Kakderi

81

Spatially controlled electro-stimulated DNA adsorption and desorption for biochip applications.  

PubMed

The manipulation of biomolecules at solid/liquid interfaces is important for the enhanced performance of a number of biomedical devices, including biochips. This study focuses on the spatial control of surface interactions of DNA as well as the electro-stimulated adsorption and desorption of DNA by appropriate surface modification of highly doped p-type silicon. Surface modification by plasma polymerisation of allylamine resulted in a surface that supported DNA adsorption and sustained cell attachment. Subsequent high-density grafting of poly(ethylene oxide) formed a low fouling layer resistant to biomolecule adsorption and cell attachment. Spatially controlled excimer laser ablation of the surface produced patterns of re-exposed plasma polymer with high-resolution. On patterned surfaces, preferential electro-stimulated adsorption of DNA to the allylamine plasma polymer surface and subsequent desorption by the application of a negative bias was observed. Furthermore, the concept presented here was investigated for use in transfection chips. Cell culture experiments with human embryonic kidney cells, using the expression of green fluorescent protein as a reporter, demonstrated efficient and controlled transfection of cells. Electro-stimulated desorption of DNA was shown to yield significantly enhanced solid phase transfection efficiencies to values of up to 30%. The ability to spatially control DNA adsorption combined with the ability to control the binding and release of DNA by application of a controlled voltage enables an advanced level of control over DNA bioactivity on solid substrates and lends itself to biochip applications. PMID:16303297

Hook, Andrew L; Thissen, Helmut; Hayes, Jason P; Voelcker, Nicolas H

2006-05-15

82

High spatial resolution aerosol retrieval with MAIAC: Application to mountain regions  

NASA Astrophysics Data System (ADS)

Aerosol spatial distribution in populated mountain areas is very heterogeneous and often characterized by scales of variability of several kilometers. Satellites provide an effective tool to map aerosols on an operational basis, but most of the aerosol products intended for continental/global applications have a coarse spatial resolution (10-18 km). The Multiangle Implementation of Atmospheric Correction (MAIAC) is a recently developed algorithm for the Moderate Resolution Imaging Spectroradiometer (MODIS), which provides Aerosol Optical Depth (AOD) at a high resolution of 1 km. We analyze the quality and potential of MAIAC AOD in the Alpine region and we derive high resolution AOD maps for the years 2008 and 2009. Cloudiness and snow in mountain regions occasionally lead to an overestimation of AOD due to unresolved cloud and snow pixel contamination. Therefore, we developed a filter that almost preserves the spatial resolution of the product to ensure the good accuracy of MAIAC AOD for air-quality and climatological applications. The AOD is validated with AERONET measurements in the region and compared to the standard MODIS AOD product (MOD04). Similar accuracies are found for both products (RMSE = 0.05) but with MAIAC providing about 50% more observations at the examined locations, because of its higher spatial resolution and less restrictive filtering. Comparison with ground measurements of aerosol mass (PM10) shows that MAIAC AOD can be used to detect the fine scales of aerosol variability (2-3 km) in the mountains. Finally, AOD maps for the Alpine region demonstrate that topography is correlated with the average aerosol spatial distribution.

Emili, E.; Lyapustin, A.; Wang, Y.; Popp, C.; Korkin, S.; Zebisch, M.; Wunderle, S.; Petitta, M.

2011-12-01

83

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

84

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

PubMed Central

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

2014-01-01

85

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

PubMed

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

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

2014-12-01

86

AN INTEGRATED SPATIAL DATA MANAGEMENT APPROACH FOR THE DEVELOPMENT OF ARCHAEOLOGICAL SITES APPLICATION TO THE SITE OF MYCENAE  

Microsoft Academic Search

Digital and automated photogrammetric methods and procedures developed for the collection and management of spatial data have been well introduced on archaeological applications. Recently, special tools in Spatial Information Systems (SIS) and management systems of virtual world models (VR) have been developed. Their combination can provide relevant scientists and users with a variety of possibilities for the creation of integrated

C. Ioannidis; S. Soile

87

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

E-print Network

QUANTIFYING LANDSCAPE PATTERN IN THE OUACHITA NATIONAL FOREST: AN ECOLOGICAL APPLICATION OF GIS-BASED SPATIAL ANALYSIS AND MODELING A Thesis by DELAYNE MARIE MEYER Submitted to the Office of Graduate Studies of Texas A&M University... in partial fulfillment of the requtrements for the degree of MASTER OF SCIENCE August I998 Major Subject: Geography QUANTIFYING LANDSCAPE PATTERN IN THE OUACHITA NATIONAL FOREST: AN ECOLOGICAL APPLICATION OF GIS-BASED SPATIAL ANALYSIS AND MODELING A...

Meyer, Delayne Marie

1998-01-01

88

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

89

Scalable digital spatial light modulator-micromesh heterostructures for real time wave optical applications.  

PubMed

For large-scale real time wave optical applications, we propose and demonstrate scalable simple digital spatial light modulator (SLM)-micromesh (?M) heterostructures, which fully harness ubiquitous well developed consumer information displays for real time large-scale SLMs and advanced patterning technologies for promoting the wave optical properties of SLMs of any size. Weakly diffractive projection mode large-scale SLMs with poor demultiplexity are transformed to highly diffractive mode heterostructures with fine patterned micromeshes as efficient demultiplexers or wave optical promoters. As a result, diffraction efficiency, diffraction angle, demultiplexity, multiplexity, reconstructed image quality and numbers of visibly reconstructed images largely increase even though the pixel pitches of the employed SLMs are many orders of magnitude larger than the wavelength of the illuminating light. The approach shown in this study can be applicable even for any sized weakly diffractive SLMs, and can simultaneously increase the effective spatial bandwidth and the physical dimension required for their wave optical applications. This can't be achieved by presently available SLMs alone. PMID:25321757

Jeong, Hoon; Choi, Jaewu

2014-09-22

90

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

91

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

92

A Novel Artificial Immune Algorithm for Spatial Clustering with Obstacle Constraint and Its Applications  

PubMed Central

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

93

Applicability of Milne-Eddington inversions to high spatial resolution observations of the quiet Sun  

NASA Astrophysics Data System (ADS)

Context. The physical conditions of the solar photosphere change on very small spatial scales both horizontally and vertically. Such a complexity may pose a serious obstacle to the accurate determination of solar magnetic fields. Aims: We examine the applicability of Milne-Eddington (ME) inversions to high spatial resolution observations of the quiet Sun. Our aim is to understand the connection between the ME inferences and the actual stratifications of the atmospheric parameters. Methods: We use magnetoconvection simulations of the solar surface to synthesize asymmetric Stokes profiles such as those observed in the quiet Sun. We then invert the profiles with the ME approximation. We perform an empirical analysis of the heights of formation of ME measurements and analyze the uncertainties brought about by the ME approximation. We also investigate the quality of the fits and their relationship with the model stratifications. Results: The atmospheric parameters derived from ME inversions of high-spatial resolution profiles are reasonably accurate and can be used for statistical analyses of solar magnetic fields, even if the fit is not always good. We also show that the ME inferences cannot be assigned to a specific atmospheric layer: different parameters sample different ranges of optical depths, and even the same parameter may trace different layers depending on the physical conditions of the atmosphere. Despite this variability, ME inversions tend to probe deeper layers in granules than in intergranular lanes. Figure 10 and appendix are only available in electronic form at http://www.aanda.org

Orozco Suárez, D.; Bellot Rubio, L. R.; Vögler, A.; Del Toro Iniesta, J. C.

2010-07-01

94

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

USGS Publications Warehouse

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

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

1996-01-01

95

Spatial light modulation techniques for system application to multipath delay estimation.  

PubMed

Three electronically addressed spatial light modulators (SLM's) are tested for their utility in forming optical taps onto an acousto-optic delay line. The SLM's are characterized as devices within a specific optical signal-processing application rather than as independent components. The signal-processing architecture described here uses a programmable tapped delay line for estimating multipath delays. Overall system performance specifications necessitate the SLM requirements. These requirements are compared with the measured performance characteristics of a magneto-optic SLM, a liquid-crystal display, and an acousto-optic deflector used as an SLM. The magneto-optic SLM and the liquid-crystal display are found to provide insufficient contrast and system light efficiency. The acousto-optic-based SLM is found to provide the best overall SLM performance for this particular optical signal processing application. PMID:20725379

Ward, M J; Keefer, C W; Welstead, S T

1992-07-10

96

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

97

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

98

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

PubMed

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

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

2013-12-01

99

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

PubMed

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

Nathoo, Farouk S; Ghosh, Pulak

2013-01-30

100

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

101

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

102

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

103

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

SciTech Connect

High resolution ({lambda}/{Delta}{lambda}{approx} 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-{mu}m {sup 55}Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10{sup -8}-10{sup -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. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Beiersdorfer, P.; Schneider, M.; Widmann, K. [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Sanchez del Rio, M. [European Synchrotron Radiation Facility, BP 220, 38043-Grenoble Cedex (France); Zhang, L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2012-10-15

104

Detection of spatially extended sources in high energy astrophysics with special application to lunar occultation  

NASA Astrophysics Data System (ADS)

Occultation is a technique that enables image reconstruction and source identification with a non-imaging detector. Such an approach is well suited for a future survey mission in nuclear astrophysics. In particular, the Lunar Occultation Technique (LOT) utilizes the Moon as an occulting object and is the basis of a new gamma-ray survey mission concept, the Lunar OCcultation Observer (LOCO). Techniques utilizing the LOT to detect spatially extended emission, from the Galactic plane or Galactic Center region, have been developed. Given knowledge of detector position in lunar orbit, combined with lunar ephemeris and relevant coordinate transformations, occultation time series can be used to reconstruct skymaps of these extended Galactic emitters. Monte-Carlo Markov Chains (MCMC), incorporating the Metropolis-Hastings algorithm for parametric model testing, form the basis of the technique. Performance of the imaging methodology, and its application to nuclear astrophysics will be presented.

Jenke, Peter Alexander

2009-01-01

105

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

106

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

NASA Technical Reports Server (NTRS)

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

Efron, Uzi (editor)

1990-01-01

107

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

E-print Network

&M University Chair of Advisory Committee: Dr. Way Kuo This study uses the spatial features of defects on the wafers to examine the detection and control of process variation in semiconductor fabrication. It applies spatial stochastic process to semiconductor... yield modeling and the extrinsic reliabil- ity estimation model. New yield models of integrated circuits based on the spatial point process are established. The defect density which varies according to location on the wafer is modeled by the spatial...

Hwang, Jung Yoon

2005-02-17

108

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

109

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

110

Performance Tests and Application Strategies of Spatial Indexes in the Embedded-GIS Data Management  

Microsoft Academic Search

Spatial indexes arranged by some sequence, are related to the positions, shapes of geographic entities and relations among them, which describe the outline info of object identifier (OID), minimum bounding rectangle (MBR) and pointers to storage location. Usually, the index situated between the spatial operating algorithms and the entities, enhances the efficiency of spatial operations by filtering and erasing irrelevant

Ma Chang-jie; Wu Xin-cai; Xie-zhong

2006-01-01

111

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

112

The development of a colour liquid crystal display spatial light modulator and applications in polychromatic optical data processing  

Microsoft Academic Search

The development of a colour Spatial Light Modulator (SLM) and its application to optical information processing is described. Whilst monochrome technology has been established for many years, this is not the case for colour where commercial systems are unavailable. A main aspect of this study is therefore, how the use of colour can add an additional dimension to optical information

John Charles Aiken

2000-01-01

113

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

114

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...

115

A bottom up approach to on-road CO2 emissions estimates: improved spatial accuracy and applications for regional  

E-print Network

(GHG) emissions is CO2 generated by the combustion of motor gasoline and diesel fuel. CO2 emissionsA bottom up approach to on-road CO2 emissions estimates: improved spatial accuracy and applications Environment Environmental Science & Technology #12;1 A bottom up approach to on-road CO2 emissions estimates

Wing, Ian Sue

116

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

117

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

118

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

119

Spatial correlations of monthly rainfall: Applications in climatology and weather modification experiments  

Microsoft Academic Search

Spatial correlations based on monthly rainfall totals from northwest Georgia for the period 1949--77 are studied. This work, a part of the Meteorological Effects of Thermal Energy Releases (METER) Program, determines natural variability rainfall trends and assists the field studies of potential precipitation effects of the Bowen Electric Generating Plant near Cartersville, Georgia. The spatial correlations, based on the overall

A. A. N. Patrinos; N. C. J. Chen; R. L. Miller

1979-01-01

120

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

121

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

ERIC Educational Resources Information Center

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

Cepeda-Cuervo, Edilberto; Núñez-Antón, Vicente

2013-01-01

122

Application of Remote Sensing for Describing Spatial-Temporal Changes in Flood Characteristics  

Microsoft Academic Search

Land use changes captured by remote sensing over a period of 21 years (1976-1997) were used to study changes in flood peaks and travel times in the Yasu River basin Japan. The impacts of these changes were simulated by a spatially distributed watershed model (SOWM-YRB). The model generates spatially distributed infiltration excess runoff and integrates the flow in the downstream

Yasuto Tachikawa; Kaoru Takara

123

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

124

A spatial bivariate probit model for correlated binary data with application to adverse birth outcomes.  

PubMed

Motivated by a study examining geographic variation in birth outcomes, we develop a spatial bivariate probit model for the joint analysis of preterm birth and low birth weight. The model uses a hierarchical structure to incorporate individual and areal-level information, as well as spatially dependent random effects for each spatial unit. Because rates of preterm birth and low birth weight are likely to be correlated within geographic regions, we model the spatial random effects via a bivariate conditionally autoregressive prior, which induces regional dependence between the outcomes and provides spatial smoothing and sharing of information across neighboring areas. Under this general framework, one can obtain region-specific joint, conditional, and marginal inferences of interest. We adopt a Bayesian modeling approach and develop a practical Markov chain Monte Carlo computational algorithm that relies primarily on easily sampled Gibbs steps. We illustrate the model using data from the 2007-2008 North Carolina Detailed Birth Record. PMID:22599322

Neelon, Brian; Anthopolos, Rebecca; Miranda, Marie Lynn

2014-04-01

125

Design of data warehouse in teaching state based on OLAP and data mining  

NASA Astrophysics Data System (ADS)

The data warehouse and the data mining technology is one of information technology research hot topics. At present the data warehouse and the data mining technology in aspects and so on commercial, financial industry as well as enterprise's production, market marketing obtained the widespread application, but is relatively less in educational fields' application. Over the years, the teaching and management have been accumulating large amounts of data in colleges and universities, while the data can not be effectively used, in the light of social needs of the university development and the current status of data management, the establishment of data warehouse in university state, the better use of existing data, and on the basis dealing with a higher level of disposal --data mining are particularly important. In this paper, starting from the decision-making needs design data warehouse structure of university teaching state, and then through the design structure and data extraction, loading, conversion create a data warehouse model, finally make use of association rule mining algorithm for data mining, to get effective results applied in practice. Based on the data analysis and mining, get a lot of valuable information, which can be used to guide teaching management, thereby improving the quality of teaching and promoting teaching devotion in universities and enhancing teaching infrastructure. At the same time it can provide detailed, multi-dimensional information for universities assessment and higher education research.

Zhou, Lijuan; Wu, Minhua; Li, Shuang

2009-04-01

126

Rough Mereology: A Survey of New Developments with Applications to Granular Computing, Spatial Reasoning and Computing with Words  

Microsoft Academic Search

In this paper, we present a survey of new developments in rough mereology, i.e. approximate calculus of parts, an approach\\u000a to reasoning under uncertainty based on the notion of an approximate part (part to a degree) along with pointers to its main\\u000a applications. The paradigms of Granule Computing (GC), Computing with Words (CWW) and Spatial Reasoning (SR) are particularly\\u000a suited

Lech Polkowski

2003-01-01

127

Application of Data Fusion in the Production and Updating of Spatial Data  

NASA Astrophysics Data System (ADS)

The increasing spatial data provide abundant material for data fusion, and the purpose of the paper is to apply data fusion into the production and updating of spatial data. After outlining the general framework and workflow, the processing contents and methods are specified in sequence. Facing various spatial data from different sources, how to design proper data fusion scheme is the toppriority problem. The method of analyzing and assessing various spatial data is introduced referring to images, which is shown by concrete examples. Then the technical workflow of multi-source data integration is present to eliminate differences and relevant contents are also specified. After building the relationships of homologous entities through spatial data matching, the data fusion which is similar to cartographic generalization in essence can be implemented. Different ways of updating spatial data is introduced to keep the currency of existing data. At last, the spatial data with good quality can be obtained. The efficient and reliability of the methodology in this paper has been proved through practical production.

Chen, H.; Sun, Q.; Xu, L.; Xiong, Z.

2013-07-01

128

Comparing and classifying one-dimensional spatial patterns: an application to laser altimeter profiles  

E-print Network

components analysis (PCA) and hierarchical cluster analysis. We illustrate our approach by comparing in French Guiana over three main landscape units with distinct geomorphological and ecological, while four classes of spatial patterns were identified by cluster analysis. Each landscape unit

Thioulouse, Jean

129

A SPATIALLY EXPLICIT HIERARCHICAL APPROACH TO MODELING COMPLEX ECOLOGICAL SYSTEMS: THEORY AND APPLICATIONS. (R827676)  

EPA Science Inventory

Ecological systems are generally considered among the most complex because they are characterized by a large number of diverse components, nonlinear interactions, scale multiplicity, and spatial heterogeneity. Hierarchy theory, as well as empirical evidence, suggests that comp...

130

December 2006 Spatial Autocorrelation and Pseudoreplication 107 Practices and Applications in Fire Ecology  

E-print Network

Ecology SPATIAL AUTOCORRELATION AND PSEUDOREPLICATION IN FIRE ECOLOGY Amanda L. Bataineh1 , Brian P the traditional statistical assumption of observational independence. What, if anything, can the fire ecology fire ecology researchers. Key Words: nearness, experimental design, ecology, landscape

Hung, I-Kuai

131

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

E-print Network

on test scenes drawn from the same source as our training set. We have designed our system for future. A flowchart of our system's capa- bilities. The Spatial-Semantic Model enables numerous useful tasks. mand

Little, Jim

132

Frequency stabilization, tuning, and spatial mode control of terahertz quantum cascade lasers for coherent transceiver applications  

NASA Astrophysics Data System (ADS)

THz quantum cascade lasers (TQCLs) first demonstrated in 2002 are a promising source of THz coherent radiation for use as both transmitters and local oscillators in coherent heterodyne detection systems. However, present TQCLs have deficiencies which include lack of frequency tunability, as well as inadequate spatial and temporal coherence. In this thesis we have addressed these issues to demonstrate an improved 2.408 TQCL which operated as a transmitter in a coherent heterodyne detection imaging system. The 2.408 THz QCL used in this thesis was grown and fabricated by the Photonics Center (University of Massachusetts Lowell). First, we showed that a short hollow Pyrex tube can act as a dielectric waveguide and transform the multimode, highly diverging TQCL beam into the lowest order dielectric waveguide hybrid mode, EH11, which then couples efficiently to the free-space Gaussian mode, TEMo0. This simple approach should enable TQCLs to be employed in applications where a spatially coherent beam is required. Next, the tunability problem was addressed. A compact, tunable, narrowband terahertz source was demonstrated by mixing a single longitudinal mode, 2.408 THz, free running quantum cascade laser with a 2-20 GHz microwave sweeper in a corner-cube-mounted Schottky diode (SD). The sideband spectra were characterized with a Fourier transform spectrometer, and the radiation was tuned through several D2O rotational transitions to estimate the longer term (t ? several seconds) bandwidth of the source. A spectral resolution of 2 MHz in the CW mode was observed. The temporal coherence of the TQCL was improved by assembling a simple analog locking circuit, which stabilizes the beat signal between the TQCL and a 2.40976 THz CO2 optically pumped molecular laser (OPL) line to 4 kHz full width at half maximum (FWHM). This is approximately a tenth of the observed long-term (t ˜ sec) linewidth of the OPL showing that the feedback loop corrects for much of the mechanical and acoustic-induced frequency jitter of the gas laser. The achieved stability is sufficient to enable the use of the TQCL as a transmitter in a coherent transceiver. Finally, a coherent transceiver using the TQCL as a transmitter and an OPL as the local oscillator was used, with a pair of SD mixers in the receiver and reference channels, to acquire high-resolution inverse synthetic aperture radar (ISAR) images of fully illuminated targets, including scale models and concealed objects. Phase stability of the received signal was sufficient to allow coherent image processing of the rotating target (in azimuth and elevation). Several THz ISAR images with submillimeter resolution, obtained with the system, are presented. These images clearly illustrate the first use of a quantum cascade laser in a coherent detection system.

Danylov, Andriy

133

Bayesian spatial models with repeated measurements: with application to the herbaceous data analysis  

Microsoft Academic Search

This paper proposes a new statistical spatial model to analyze and predict the coverage percentage of the upland ground flora\\u000a in the Missouri Ozark Forest Ecosystem Project (MOFEP). The flora coverage percentages are collected from clustered locations,\\u000a which requires a new spatial model other than the traditional kriging method. The proposed model handles this special data\\u000a structure by treating the

Xiaoqian Sun; Zhuoqiong He; Jing Zhang; John Kabrick

2009-01-01

134

A permutation test of spatial randomness: application to nearest neighbour indices in forest stands  

Microsoft Academic Search

The ability to precisely describe forest spatial structures, and their modifications through timber harvesting, is of prime\\u000a importance for sustainable management of complex forest ecosystems, especially regarding uneven-aged, multi-species forests.\\u000a For this purpose, forest managers require statistical indices that are meaningful descriptors of the spatial structure of\\u000a a given forest ecosystem. This paper presents a new sensitive permutation test of

José Javier Corral-Rivas; Christian Wehenkel; Hermes Alejandro Castellanos-Bocaz; Benedicto Vargas-Larreta; Ulises Diéguez-Aranda

2010-01-01

135

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

136

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

PubMed Central

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

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

2015-01-01

137

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

NASA Astrophysics Data System (ADS)

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

Chen, Shanqin; Zhang, Yong-Tao

2011-05-01

138

Evaluation of and compensation for spatial noise of LCDs in medical applications.  

PubMed

Recent developments in liquid crystal display (LCD) technology suggest that this technology will replace the cathode ray tube (CRT) as the most popular softcopy display technology in the medical arena. However, LCDs are far from ideal for medical imaging. One of the principal problems they possess is spatial noise contamination, which requires accurate characterization and appropriate compensation before LCD images can be effectively utilized for reliable diagnosis. This paper presents some work we have conducted recently on characterization of spatial noise of high resolution LCDs. The primary purpose of this work is to explore the properties of spatial noise and propose a method to reduce it. A high quality CCD camera was used for physical evaluation. Spatial noise properties were analyzed and estimated from the camera images via signal modeling and processing. A noise compensation algorithm based on error diffusion was developed to process images before they were displayed. Results shown in this paper suggest that LCD spatial noise can be effectively reduced via appropriate processing. PMID:15789605

Fan, Jiahua; Roehrig, Hans; Sundareshan, Malur K; Krupinski, Elizabeth; Dallas, William J; Gandhi, Kunal

2005-02-01

139

Monitoring survival rates of landbirds at varying spatial scales: An application of the MAPS Program  

USGS Publications Warehouse

Survivorship is a primary demographic parameter affecting population dynamics, and thus trends in species abundance. The Monitoring Avian Productivity and Survivorship (MAPS) program is a cooperative effort designed to monitor landbird demographic parameters. A principle goal of MAPS is to estimate annual survivorship and identify spatial patterns and temporal trends in these rates. We evaluated hypotheses of spatial patterns in survival rates among a collection of neighboring sampling sites, such as within national forests, among biogeographic provinces, and between breeding populations that winter in either Central or South America, and compared these geographic-specific models to a model of a common survival rate among all sampling sites. We used data collected during 1992-1995 from Swainson's Thrush (Cathorus ustulatus) populations in the western region of the United States. We evaluated the ability to detect spatial and temporal patterns of survivorship with simulated data. We found weak evidence of spatial differences in survival rates at the local scale of 'location,' which typically contained 3 mist-netting stations. There was little evidence of differences in survival rates among biogeographic provinces or between populations that winter in either Central or South America. When data were pooled for a regional estimate of survivorship, the percent relative bias due to pooling 'locations' was 12 years of monitoring. Detection of spatial patterns and temporal trends in survival rates from local to regional scales will provide important information for management and future research directed toward conservation of landbirds.

Rosenberg, D.K.; DeSante, D.F.; Hines, J.E.

2000-01-01

140

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

PubMed Central

Twitter has become a popular data source as a surrogate for monitoring and detecting events. Targeted domains such as crime, election, and social unrest require the creation of algorithms capable of detecting events pertinent to these domains. Due to the unstructured language, short-length messages, dynamics, and heterogeneity typical of Twitter data streams, it is technically difficult and labor-intensive to develop and maintain supervised learning systems. We present a novel unsupervised approach for detecting spatial events in targeted domains and illustrate this approach using one specific domain, viz. civil unrest modeling. Given a targeted domain, we propose a dynamic query expansion algorithm to iteratively expand domain-related terms, and generate a tweet homogeneous graph. An anomaly identification method is utilized to detect spatial events over this graph by jointly maximizing local modularity and spatial scan statistics. Extensive experiments conducted in 10 Latin American countries demonstrate the effectiveness of the proposed approach. PMID:25350136

Zhao, Liang; Chen, Feng; Dai, Jing; Hua, Ting; Lu, Chang-Tien; Ramakrishnan, Naren

2014-01-01

141

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

142

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...

143

Spatial Lasso with Applications to GIS Model Selection Hsin-Cheng Huang  

E-print Network

to a modification of the Lasso procedure. The LARS algorithm, which can be used in a fast implementation of Lasso include information on geology, topography, weather and climate, ownership, political administration, land to a modification of the Lasso procedure that we call spatial Lasso. The model and the implementation of standard

144

Application of a spatial decision support system (SDSS) to reduce soil erosion in northern Ethiopia  

Microsoft Academic Search

A spatial decision support system (SDSS) based on multi-criteria and multi-objective decision analysis is applied in a case study in Ethiopia to reduce soil erosion on the basis of reallocation of crops according to their capacity to protect the soil. The case study is carried out in the Adwa district. The SDSS has been implemented using the widespread GIS software

Massimo Dragan; Enrico Feoli; Michele Fernetti; Woldu Zerihun

2003-01-01

145

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

146

Spatial division multiple access technology and its application to wireless communication systems  

Microsoft Academic Search

Space is one of the “final frontiers” when it comes to next generation wireless communication systems. Large-scale penetration of such such systems into our daily lives will require significant reductions in cost and increases in capacity, benefits proper exploitation of the spatial dimension can offer. That this is certainly the case is attested to by the significant number of companies

R. H. Roy

1997-01-01

147

Design of control policies for spatially inhomogeneous robot swarms with application to commercial pollination  

Microsoft Academic Search

We present an approach to designing scalable, decentralized control policies that produce a desired collective behavior in a spatially inhomogeneous robotic swarm that emulates a system of chemically reacting molecules. Our ap- proach is based on abstracting the swarm to an advection- diffusion-reaction partial differential equation model, which we solve numerically using smoothed particle hydrodynamics (SPH), a meshfree technique that

Spring Berman; Vijay Kumar; Radhika Nagpal

2011-01-01

148

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

149

APPLICATION OF THE DYNAMIC SPATIAL ORDERED PROBIT MODEL: PATTERNS OF OZONE CONCENTRATION IN AUSTIN, TEXAS  

Microsoft Academic Search

While a wide variety of transportation data sets involve discrete values scattered across space and time, few techniques presently exist to prope rly analyze such data. A new dynamic spatial ordered probit model (DSOP) is described here, a nd its use is demonstrated for a case of ozone concentration categories. Using outputs of phot ochemical models for the Austin, Texas

Kara M. Kockelman

150

High-resolution modeling of the spatial heterogeneity of soil moisture: Applications in network design  

NASA Astrophysics Data System (ADS)

The spatial heterogeneity of soil moisture remains a persistent challenge in the design of in situ measurement networks, spatial downscaling of coarse estimates (e.g., satellite retrievals), and hydrologic modeling. To address this challenge, we analyze high-resolution (˜9 m) simulated soil moisture fields over the Little River Experimental Watershed (LREW) in Georgia, USA, to assess the role and interaction of the spatial heterogeneity controls of soil moisture. We calibrate and validate the TOPLATS distributed hydrologic model with high to moderate resolution land and meteorological data sets to provide daily soil moisture fields between 2004 and 2008. The results suggest that topography and soils are the main drivers of spatial heterogeneity over the LREW. We use this analysis to introduce a novel network design method that uses land data sets as proxies of the main drivers of local heterogeneity (topography, land cover, and soil properties) to define unique and representative hydrologic similar units (subsurface, surface, and vegetation) for probe placement. The calibration of the hydrologic model and network design method illustrates how the use of hydrologic similar units in hydrologic modeling could minimize computation and guide efforts toward improved macroscale land surface modeling.

Chaney, Nathaniel W.; Roundy, Joshua K.; Herrera-Estrada, Julio E.; Wood, Eric F.

2015-01-01

151

Spatial CDF Estimation and Visualization with Applications to Forest Health Monitoring  

E-print Network

in an interactive environment. The environment supports computation and visualization of CDFs over several spatial of ecological resources is of vital importance to the nation. Changes in the environment of a long, large-scale, long-term monitoring programs can be found in the articles by Messer, Linthurst

Symanzik, Jürgen

152

Extending Data Mining for Spatial Applications: A Case Study in Predicting Nest Locations  

E-print Network

management, protection of critical habitat and endangered species. Since the underlying process governing a case for the need for a new measure of spa­ tial classification accuracy. 1.1 An Illustrative in the development of spatial model for the nesting locations of a marsh­nesting bird species [15, 16]. We will use

Shekhar, Shashi

153

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

154

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

Microsoft Academic Search

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

George L. W. Perry

2004-01-01

155

The Application of the Spectral and Spatial Characteristics of the Earth's Infrared Horizon to Horizon Scanners  

Microsoft Academic Search

The spectral and spatial characteristics of the Earth's infrared background are presented. It is shown that the vibration band of CO2 centered at 15 ¿ provides maximum discrimination against clouds at the tropopause. An optimum spectral bandwidth is defined and the radiance values computed as a function of scan angle for different latitudes. These data are used to produce the

James W. Burn

1963-01-01

156

Spatial prediction model and its application to chemistry of atmospheric precipitation in Jordan  

NASA Astrophysics Data System (ADS)

This study is concerned with the spatial variability of some wet atmospheric precipitation parameters such as; pH, conductivity (EC). The study also depicts the spatial variability of some ions (cations and anions) of atmospheric precipitation in Jordan such as, Ca 2+, Mg 2+, Na + and K +, HCO 3-, Cl -, NO 3- and SO 42-. The basis of the work is to establish a relationship through the cumulative semivariogram technique between the distance ratios and the spatial dependence structure of the chemical composition of atmospheric precipitation. All semivariogram models are constructed in this study in order to understand the behavior of the spatial distribution. The spatial distributions of rainwater parameters show differences from station to station which is expressed in terms of angle, where the larger the angle the weaker the correlation. The semivariogram (SV) models are constructed to show the variation of the rainfall chemistry in Jordan. The SV models show weak correlation between mountain and leeside mountain stations, i.e. mountain and desert stations. On the other hand, good correlations are observed when transferring from south to north of the country. The larger is the found angle, the weaker is the correlation. For most of the SV model the correlation is found to be very weak between desert and mountainous locality. The Standard Regional Dependence Factor (SRDF) is used for prediction of the distribution of rain fall parameters. It shows the relative error between observed and predicted values of rainwater parameters. The overall regional relative error between the observed and estimated concentrations remains less than 15%.

Al-Khashman, Omar Ali; Tarawneh, Qassem Y.

2007-06-01

157

Regional and Temporal Variation in Methamphetamine-Related Incidents: Applications of Spatial and Temporal Scan Statistics  

PubMed Central

Introduction This investigation utilized spatial scan statistics, geographic information systems and multiple data sources to assess spatial clustering of statewide methamphetamine-related incidents. Temporal and spatial associations with regulatory interventions to reduce access to precursor chemicals (pseudoephedrine) were also explored. Methods Four statewide data sources were utilized including regional poison control center statistics, fatality incidents, methamphetamine laboratory seizures, and hazardous substance releases involving methamphetamine laboratories. Spatial clustering of methamphetamine incidents was assessed using SaTScan™. SaTScan™ was also utilized to assess space-time clustering of methamphetamine laboratory incidents, in relation to the enactment of regulations to reduce access to pseudoephedrine. Results Five counties with a significantly higher relative risk of methamphetamine-related incidents were identified. The county identified as the most likely cluster had a significantly elevated relative risk of methamphetamine laboratories (RR=11.5), hazardous substance releases (RR=8.3), and fatalities relating to methamphetamine (RR=1.4). A significant increase in relative risk of methamphetamine laboratory incidents was apparent in this same geographic area (RR=20.7) during the time period when regulations were enacted in 2004 and 2005, restricting access to pseudoephedrine. Subsequent to the enactment of these regulations, a significantly lower rate of incidents (RR 0.111, p=0.0001) was observed over a large geographic area of the state, including regions that previously had significantly higher rates. Conclusions Spatial and temporal scan statistics can be effectively applied to multiple data sources to assess regional variation in methamphetamine-related incidents, and explore the impact of preventive regulatory interventions. PMID:19225949

Sudakin, Daniel L.

2009-01-01

158

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

E-print Network

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

Noam, Yair

2012-01-01

159

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

Microsoft Academic Search

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

Calvin Coopmans; YangQuan Chen

2008-01-01

160

An Application Based on Spatial-Relationship to Basketball Defensive Strategies  

Microsoft Academic Search

\\u000a This paper aims to develop a simulated system used for teaching and training basketball defensive strategies.  Respectively,\\u000a defensive strategies can be described within one method by editing video recorded from basketball games into desired clips\\u000a for analysis and storing them into the database. In this paper, we used Spatial-Temporal Relationships to describe the local\\u000a defensive movements by the basketball players

Su-li Chin; Chun-hong Huang; Chia-tong Tang; Jason C. Hung

2005-01-01

161

Spatial data mining application based on ant colony algorithm and FCM for region traffic network evaluation  

NASA Astrophysics Data System (ADS)

The spatial data in GIS-T database is huge and complicated, discovery knowledge from this database is very important, region traffic network evaluation is one of the important contents. In this paper the author referred to an integrated algorithm combined Ant colony algorithm with FCM to cluster the traffic data of 15 regions of Hubei Province, then used the method of maximizing deviation to arrange the clustering result. From the result we can evaluate the traffic conditions of the 15 regions.

Wang, Wei; Wang, Peng; Qi, Wei; Zhang, Bo; Wang, Quan

2008-12-01

162

Spatial Rule-Based Modeling: A Method and Its Application to the Human Mitotic Kinetochore  

PubMed Central

A common problem in the analysis of biological systems is the combinatorial explosion that emerges from the complexity of multi-protein assemblies. Conventional formalisms, like differential equations, Boolean networks and Bayesian networks, are unsuitable for dealing with the combinatorial explosion, because they are designed for a restricted state space with fixed dimensionality. To overcome this problem, the rule-based modeling language, BioNetGen, and the spatial extension, SRSim, have been developed. Here, we describe how to apply rule-based modeling to integrate experimental data from different sources into a single spatial simulation model and how to analyze the output of that model. The starting point for this approach can be a combination of molecular interaction data, reaction network data, proximities, binding and diffusion kinetics and molecular geometries at different levels of detail. We describe the technique and then use it to construct a model of the human mitotic inner and outer kinetochore, including the spindle assembly checkpoint signaling pathway. This allows us to demonstrate the utility of the procedure, show how a novel perspective for understanding such complex systems becomes accessible and elaborate on challenges that arise in the formulation, simulation and analysis of spatial rule-based models. PMID:24709796

Ibrahim, Bashar; Henze, Richard; Gruenert, Gerd; Egbert, Matthew; Huwald, Jan; Dittrich, Peter

2013-01-01

163

Application of spatial technology in malaria research & control: some new insights.  

PubMed

Geographical information System (GIS) has emerged as the core of the spatial technology which integrates wide range of dataset available from different sources including Remote Sensing (RS) and Global Positioning System (GPS). Literature published during the decade (1998-2007) has been compiled and grouped into six categories according to the usage of the technology in malaria epidemiology. Different GIS modules like spatial data sources, mapping and geo-processing tools, distance calculation, digital elevation model (DEM), buffer zone and geo-statistical analysis have been investigated in detail, illustrated with examples as per the derived results. These GIS tools have contributed immensely in understanding the epidemiological processes of malaria and examples drawn have shown that GIS is now widely used for research and decision making in malaria control. Statistical data analysis currently is the most consistent and established set of tools to analyze spatial datasets. The desired future development of GIS is in line with the utilization of geo-statistical tools which combined with high quality data has capability to provide new insight into malaria epidemiology and the complexity of its transmission potential in endemic areas. PMID:19797808

Saxena, Rekha; Nagpal, B N; Srivastava, Aruna; Gupta, S K; Dash, A P

2009-08-01

164

MAD: a new method for inverse modeling of spatial random fields with applications in hydrogeology  

NASA Astrophysics Data System (ADS)

We propose the Method of Anchored Distributions (MAD) for calibrating the model of a spatial random field using both local and non-local data. Using hydraulic conductivity as an example of the spatial variable of interest, local data refer to "point" measurements of conductivity or covariates that provide "point" conductivity, whereas non-local data refer to observations of a process that rely on the conductivity field. The proposed method is a general, Bayesian statistical framework. Main features include: (1) the parameterization of the spatial random field is versatile; (2) a systematic classification of all relevant data permits systematic treatment of individual datasets according to their category, making the framework very general; (3) no assumptions are made on the non-local process (a.k.a forward model), e.g. roughly linear, or small variance; (4) the result by construction provides conditional simulations of the field, i.e., by randomly sampling a distribution conditional on the data, as opposed to optimization in order to "match" the data. We will illustrate the method by synthetic examples.

Zhang, Z.; Rubin, Y.

2008-12-01

165

In Vivo Application of Short-Lag Spatial Coherence Imaging in Human Liver  

PubMed Central

We present the results of a patient study conducted to assess the performance of two novel imaging methods, namely Short-Lag Spatial Coherence (SLSC) and Harmonic Spatial Coherence Imaging (HSCI), in in vivo liver environment. Similar in appearance to the B-mode images, SLSC and HSCI images are based solely on the spatial coherence of fundamental and harmonic echo data, respectively, and do not depend on the echo magnitude. SLSC and HSCI suppress incoherent echo signals and thus tend to reduce clutter. The SLSC and HSCI images of 17 patients demonstrate sharper delineation of blood vessel walls, suppressed clutter inside the vessel lumen, and show reduced speckle in surrounding tissue compared to matched B-modes. Target contrast and contrast-to-noise ratio (CNR) show statistically significant improvements between fundamental B-mode and SLSC imaging and between harmonic B-mode and HSCI imaging (in all cases p < 0.01). The magnitude of improvement in contrast and CNR increases as the overall quality of B-mode images decreases. Poor quality fundamental B-mode images (where image quality classification is based on both contrast and CNR) exhibit the highest improvements in both contrast and CNR (288 % improvement in contrast and 533 % improvement in CNR). PMID:23347642

Jakovljevic, Marko; Trahey, Gregg E.; Nelson, Rendon C.; Dahl, Jeremy J.

2013-01-01

166

A Bayesian normal mixture accelerated failure time spatial model and its application to prostate cancer.  

PubMed

In the United States, prostate cancer is the third most common cause of death from cancer in males of all ages, and the most common cause of death from cancer in males over age 75. It has been recognized that the incidence of the prostate cancer is high in African Americans, and its occurrence and progression may be impacted by geographical factors. In order to investigate the spatial effects and racial disparities for prostate cancer in Louisiana, in this article we propose a normal mixture accelerated failure time spatial model, which does not require the proportional hazards assumption and allows the multi-model distribution to be modeled. The proposed model is estimated with a Bayesian approach and it can be easily implemented in WinBUGS. Extensive simulations show that the proposed model provides decent flexibility for a variety of parametric error distributions. The proposed method is applied to 2000-2007 Louisiana prostate cancer data set from the Surveillance, Epidemiology and End Results Program. The results reveal the possible spatial pattern and racial disparities for prostate cancer in Louisiana. PMID:23117407

Wang, Songfeng; Zhang, Jiajia; Lawson, Andrew B

2012-11-01

167

Spatial correlation analysis of isotropic microvessels: methodology and application to thyroid capillaries.  

PubMed

The study of relations between structural organization and functions of microcirculatory networks is a major aim of modern microangiology. Such a structural aspect of microvessels (MVs) as their spatial arrangement has substantial influence on their transport and other functional properties. This paper describes a methodology of spatial correlation analysis for isotropic blood and lymphatic MVs which is based on a stereological estimator of the pair correlation function [g3D(r)] created recently by the authors for systems of elongated objects. The following main features of the methodology are presented: (i) interpretation of the shape of g3D(r) curves, (ii) their quantitative description by numerical parameters, and (iii) limitations of the method arising from statistical requirements to MVs under investigation. The methodology is considered in the light of multilevel sampling designs, which are typical for biomedical morphology. The estimator with its methodological framework is applied to perifollicular blood capillaries in the adult rat thyroid. Related methods for studying the spatial arrangement of MVs are thoroughly discussed in the paper. PMID:16598655

Krasnoperov, Renat A; Stoyan, Dietrich

2006-05-01

168

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

169

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

170

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

171

Application of spatial EOF and multivariate time series model for evaluating agricultural drought vulnerability in Korea  

NASA Astrophysics Data System (ADS)

This study proposed a methodology using the empirical orthogonal function (EOF) and multivariate time series model for the analysis of drought both in time and space. The methodology proposed was then applied to evaluate the vulnerability of agricultural drought of major river basins in Korea. First, the three-month SPI data from 59 rain gauge stations over the Korean Peninsula were analyzed by deriving and spatially characterizing the EOFs. The shapes of major estimated EOFs were found to well reflect the observed spatial pattern of droughts. Second, the coefficient time series of estimated EOFs were then fitted by a multivariate time series model to generate the SPI data for 10,000 years, which were used to derive the annual maxima series of areal average drought severity over the Korean Peninsula. These annual maxima series were then analyzed to determine the mean drought severity for given return periods. Four typical spatial patterns of drought severity could also be selected for those return periods considered. This result shows that the southern part of the Korean Peninsula is most vulnerable to drought than the other parts. Finally, the agricultural drought vulnerability was evaluated by considering the potential water supply from dams. In an ideal case, when all the maximum dam storage was assumed to be assigned to agriculture, all river basins in Korea were found to have the potential to overcome a 30-year drought. However, under more realistic conditions considering average dam storage and water allocation priorities, most of the river basins could not overcome a 30-year drought.

Kim, Dae Ha; Yoo, Chulsang; Kim, Tae-Woong

2011-03-01

172

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

173

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

174

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

NASA Astrophysics Data System (ADS)

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.

Wohlfahrt, Georg; Tasser, Erich

2014-07-01

175

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

NASA Astrophysics Data System (ADS)

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

Tasser, Erich; Wohlfahrt, Georg

2014-05-01

176

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

177

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

178

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

179

Passive microwave derived snowmelt timing: significance, spatial and temporal variability, and potential applications  

NASA Astrophysics Data System (ADS)

Snow accumulation and melt are dynamic features of the cryosphere indicative of a changing climate. Spring melt and refreeze timing are of particular importance due to the influence on subsequent hydrological and ecological processes, including peak runoff and green-up. To investigate the spatial and temporal variability of melt timing across a sub-arctic region (the Yukon River Basin (YRB), Alaska/Canada) dominated by snow and lacking substantial ground instrumentation, passive microwave remote sensing was utilized to provide daily brightness temperatures (Tb) regardless of clouds and darkness. Algorithms to derive the timing of melt onset and the end of melt-refreeze, a critical transition period where the snowpack melts during the day and refreezes at night, were based on thresholds for Tb and diurnal amplitude variations (day and night difference). Tb data from the Special Sensor Microwave Imager (1988 to 2011) was used for analyzing YRB terrestrial snowmelt timing and for characterizing melt regime patterns for icefields in Alaska and Patagonia. Tb data from the Advanced Microwave Scanning Radiometer for EOS (2003 to 2010) was used for determining the occurrence of early melt events (before melt onset) associated with fog or rain on snow, for investigating the correlation between melt timing and forest fires, and for driving a flux-based snowmelt runoff model. From the SSM/I analysis: the melt-refreeze period lengthened for the majority of the YRB with later end of melt-refreeze and earlier melt onset; and positive Tb anomalies were found in recent years from glacier melt dynamics. From the AMSR-E analysis: early melt events throughout the YRB were most often associated with warm air intrusions and reflect a consistent spatial distribution; years and areas of earlier melt onset and refreeze had more forest fire occurrences suggesting melt timing's effects extend to later seasons; and satellite derived melt timing served as an effective input for model simulation of discharge in remote, ungauged snow-dominated basins. The melt detection methodology and results present a new perspective on the changing cryosphere, provide an understanding of melt's influence on other earth system processes, and develop a baseline from which to assess and evaluate future change. The temporal and spatial variability conveyed through the regional context of this research may be useful to communities in climate change adaptation planning.

Semmens, Kathryn Alese

180

Spatial three-dimensional landslide susceptibility mapping tool and its applications  

NASA Astrophysics Data System (ADS)

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

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

181

Optimal steering for kinematic vehicles with applications to spatially distributed agents  

NASA Astrophysics Data System (ADS)

While there is no universal method to address control problems involving networks of autonomous vehicles, there exist a few promising schemes that apply to different specific classes of problems, which have attracted the attention of many researchers from different fields. In particular, one way to extend techniques that address problems involving a single autonomous vehicle to those involving teams of autonomous vehicles is to use the concept of Voronoi diagram. The Voronoi diagram provides a spatial partition of the environment the team of vehicles operate in, where each element of this partition is associated with a unique vehicle from the team. The partition induces a graph abstraction of the operating space that is in an one-to-one correspondence with the network abstraction of the team of autonomous vehicles; a fact that can provide both conceptual and analytical advantages during mission planning and execution. In this dissertation, we propose the use of a new class of Voronoi-like partitioning schemes with respect to state-dependent proximity (pseudo-) metrics rather than the Euclidean distance or other generalized distance functions, which are typically used in the literature. An important nuance here is that, in contrast to the Euclidean distance, state-dependent metrics can succinctly capture system theoretic features of each vehicle from the team (e.g., vehicle kinematics), as well as the environment-vehicle interactions, which are induced, for example, by local winds/currents. We subsequently illustrate how the proposed concept of state-dependent Voronoi-like partition can induce local control schemes for problems involving networks of spatially distributed autonomous vehicles by examining a sequential pursuit problem of a maneuvering target by a group of pursuers distributed in the plane. The construction of generalized Voronoi diagrams with respect to state-dependent metrics poses some significant challenges. First, the generalized distance metric may be a function of the direction of motion of the vehicle (anisotropic pseudo-distance function) and/or may not be expressible in closed form. Second, such problems fall under the general class of partitioning problems for which the vehicles' dynamics must be taken into account. The topology of the vehicle's configuration space may be non-Euclidean, for example, it may be a manifold embedded in a Euclidean space. In other words, these problems may not be reducible to generalized Voronoi diagram problems for which efficient construction schemes, analytical and/or computational, exist in the literature. This research effort pursues three main objectives. First, we present the complete solution of different steering problems involving a single vehicle in the presence of motion constraints imposed by the maneuverability envelope of the vehicle and/or the presence of a drift field induced by winds/currents in its vicinity. The analysis of each steering problem involving a single vehicle provides us with a state-dependent generalized metric, such as the minimum time-to-go/come. We subsequently use these state-dependent generalized distance functions as the proximity metrics in the formulation of generalized Voronoi-like partitioning problems. The characterization of the solutions of these state-dependent Voronoi-like partitioning problems using either analytical or computational techniques constitutes the second main objective of this dissertation. The third objective of this research effort is to illustrate the use of the proposed concept of state-dependent Voronoi-like partition as a means for passing from control techniques that apply to problems involving a single vehicle to problems involving networks of spatially distributed autonomous vehicles. To this aim, we formulate the problem of sequential/relay pursuit of a maneuvering target by a group of spatially distributed pursuers and subsequently propose a distributed group pursuit strategy that directly derives from the solution of a state-dependent Voronoi-like partitioning problem. (Abstract shortened by UMI.)

Brown, Scott; Praeger, Cheryl E.; Giudici, Michael

182

Spatial and temporal evolution of microdischarges in Surface Dielectric Barrier Discharges for aeronautical applications plasmas  

NASA Astrophysics Data System (ADS)

Surface Dielectric Barrier Discharges have been proposed long ago as a tool to improve aerodynamics and flow performances. Such electrical discharges could be employed to energize the gas phase and to induce flows. The discharge itself consists of a large number of repetitions of single electric current pulses, with short duration and limited spatial extension filling the region near electrodes. The connection between such macroscopic effect and the properties of the single microdischarge events has been investigated. In particular we have measured the direction and the velocity of propagation of the ionization wave during the different phases of the voltage cycle. Light collected from different parts of the gap arrives at a photomultiplier tube with a delay proportional to the velocity of the ionization wave. The measured propagation velocity was estimated as about 220 km/s in the so called backward discharge phase.

Barni, R.; Biganzoli, I.; Riccardi, C.

2014-11-01

183

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

184

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

185

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

186

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

187

Cryogen spray cooling for spatially selective photocoagulation: a feasibility study with potential application for treatment of hemangiomas  

NASA Astrophysics Data System (ADS)

The clinical objective in laser treatment of hemangiomas is to photocoagulate the dilated cutaneous blood vessels, while at the same time minimizing nonspecific thermal injury to the overlying epidermis. We present an in-vivo experimental procedure, using a chicken comb animal model, and an infrared feedback system to deliver repetitive cryogen spurts during continuous Nd:YAG laser irradiation. Gross and histologic observations are consistent with calculated thicknesses of protected and damaged tissues, and demonstrate the feasibility of inducing spatially selective photocoagulation when using cryogen spray cooling in conjunction with laser irradiation. Experimental observation of epidermal protection in the chicken comb model suggests selective photocoagulation of subsurface targeted blood vessels for successful treatment of hemangiomas can be achieved by repetitive applications of a cryogen spurt during continuous Nd:YAG laser irradiation.

Anvari, Bahman; Tanenbaum, B. S.; Milner, Thomas E.; Hoffman, Wendy; Said, Samireh; Chang, Cheng-Jen; Liaw, Lih-Huei L.; Kimel, Sol; Nelson, J. Stuart

1996-12-01

188

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

Microsoft Academic Search

This paper describes the application of electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by a layer-by-layer (LbL) technique and mounted with electrodes along their boundaries. The response of the thin films to various stimuli is investigated by relying on electric current

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

2007-01-01

189

Spatial analysis based on GIS in the application of construction of urban underground rail  

Microsoft Academic Search

The monitoring of construction for metro is an important procedure of guaranteeing construction safety and engineering quality, but the current monitoring data processing, analysis and transfer methods are unable to meet the need of safety management. Based on requirement investigation in metro companies, This paper puts forward a method with application of GIS software ArcGIS9.3. The functions of which such

Jian-hua Jia; Cui Wang

2010-01-01

190

Spatial Variability and Application of Ratios between BTEX in Two Canadian Cities  

PubMed Central

Spatial monitoring campaigns of volatile organic compounds were carried out in two similarly sized urban industrial cities, Windsor and Sarnia, ON, Canada. For Windsor, data were obtained for all four seasons at approximately 50 sites in each season (winter, spring, summer, and fall) over a three-year period (2004, 2005, and 2006) for a total of 12 sampling sessions. Sampling in Sarnia took place at 37 monitoring sites in fall 2005. In both cities, passive sampling was done using 3M 3500 organic vapor samplers. This paper characterizes benzene, toluene, ethylbenzene, o, and (m + p)-xylene (BTEX) concentrations and relationships among BTEX species in the two cities during the fall sampling periods. BTEX concentration levels and rank order among the species were similar between the two cities. In Sarnia, the relationships between the BTEX species varied depending on location. Correlation analysis between land use and concentration ratios showed a strong influence from local industries. Use one of the ratios between the BTEX species to diagnose photochemical age may be biased due to point source emissions, for example, 53 tonnes of benzene and 86 tonnes of toluene in Sarnia. However, considering multiple ratios leads to better conclusions regarding photochemical aging. Ratios obtained in the sampling campaigns showed significant deviation from those obtained at central monitoring stations, with less difference in the (m + p)/E ratio but better overall agreement in Windsor than in Sarnia. PMID:22235184

Miller, Lindsay; Xu, Xiaohong; Wheeler, Amanda; Atari, Dominic Odwa; Grgicak-Mannion, Alice; Luginaah, Isaac

2011-01-01

191

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

192

Application of high spatial resolution airborne hyperspectral remote sensing data in thematic information extraction  

NASA Astrophysics Data System (ADS)

The airborne hyperspectral remote sensing data, such as PHI, OMIS, has the virtues of high spatial and spectral resolution. Hence, from the view of target classification we can consider that it can provide the ability of discriminating targets more detailedly than other data. So it's important to extract thematic information and update database using this kind of data. Whereas, the hyperspectral data has abundant bands and high between-band correlation, the traditional classification methods such as maximum likelihood classifier (MLC) and spectral angle mapper (SAM) have performed poorly in thematic information extraction. For this reason, we present a new method for thematic information extraction with hyperspectral remote sensing data. We perform classification by means of combining the self-organizing map (SOM) neural network which is considered as full-pixel technique with linear spectral mixture analysis (LSMA) which is considered as mixed-pixel technique. The SOM neural network is improved from some aspects to classify the pure data and find the mixed data. And then the mixed data are unmixed and classified by LSMA. The result of experiment shows that we can have the better performance in thematic information extraction with PHI by this means.

Xu, Hong-gen; Ma, Hong-chao; Li, De-ren; Song, Yan

2006-10-01

193

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

194

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

195

Slot Index Spatial Join  

Microsoft Academic Search

Efficient processing of spatial joins is very important due to their high cost and frequent application in spatial databases and other areas involving multidimensional data. This paper proposes slot index spatial join (SISJ), an algorithm that joins a nonindexed data set with one indexed by an R-tree. We explore two optimization techniques that reduce the space requirements and the computational

Nikos Mamoulis; Dimitris Papadias

2003-01-01

196

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

197

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

198

Closed-loop adaptive optics using a spatial light modulator for sensing and compensating of optical aberrations in ophthalmic applications.  

PubMed

Sensing and compensating of optical aberrations in closed-loop mode using a single spatial light modulator (SLM) for ophthalmic applications is demonstrated. Notwithstanding the disadvantages of the SLM, in certain cases, this multitasking capability of the device makes it advantageous over existing deformable mirrors (DMs), which are expensive and in general used for aberration compensation alone. A closed-loop adaptive optics (AO) system based on a single SLM was built. Beam resizing optics were used to utilize the large active area of the device and hence make it feasible to generate 137 active subapertures for wavefront sensing. While correcting Zernike aberrations up to fourth order introduced with the help of a DM (for testing purposes), diffraction-limited resolution was achieved. It is shown that matched filter and intensity-weighted centroiding techniques stand out among others. Closed-loop wavefront correction of aberrations in backscattered light from the eyes of three healthy human subjects was demonstrated after satisfactory results were obtained using an artificial eye, which was simulated with a short focal length lens and a sheet of white paper as diffuser. It is shown that the closed-loop AO system based on a single SLM is capable of diffraction-limited correction for ophthalmic applications. PMID:25253296

Akondi, Vyas; Jewel, Md Atikur Rahman; Vohnsen, Brian

2014-09-01

199

Closed-loop adaptive optics using a spatial light modulator for sensing and compensating of optical aberrations in ophthalmic applications  

NASA Astrophysics Data System (ADS)

Sensing and compensating of optical aberrations in closed-loop mode using a single spatial light modulator (SLM) for ophthalmic applications is demonstrated. Notwithstanding the disadvantages of the SLM, in certain cases, this multitasking capability of the device makes it advantageous over existing deformable mirrors (DMs), which are expensive and in general used for aberration compensation alone. A closed-loop adaptive optics (AO) system based on a single SLM was built. Beam resizing optics were used to utilize the large active area of the device and hence make it feasible to generate 137 active subapertures for wavefront sensing. While correcting Zernike aberrations up to fourth order introduced with the help of a DM (for testing purposes), diffraction-limited resolution was achieved. It is shown that matched filter and intensity-weighted centroiding techniques stand out among others. Closed-loop wavefront correction of aberrations in backscattered light from the eyes of three healthy human subjects was demonstrated after satisfactory results were obtained using an artificial eye, which was simulated with a short focal length lens and a sheet of white paper as diffuser. It is shown that the closed-loop AO system based on a single SLM is capable of diffraction-limited correction for ophthalmic applications.

Akondi, Vyas; Jewel, Md. Atikur Rahman; Vohnsen, Brian

2014-09-01

200

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

PubMed Central

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

Warburton, Bruce; Gormley, Andrew M.

2015-01-01

201

Application of geostatistics with Indicator Kriging for analyzing spatial variability of groundwater arsenic concentrations in Southwest Bangladesh  

Microsoft Academic Search

This article seeks to explore the spatial variability of groundwater arsenic (As) concentrations in Southwestern Bangladesh. Facts about spatial pattern of As are important to understand the complex processes of As concentrations and its spatial predictions in the unsampled areas of the study site. The relevant As data for this study were collected from Southwest Bangladesh and were analyzed with

M. Manzurul Hassan; Peter J. Atkins

2011-01-01

202

Testing for spatial correlation and semiparametric spatial modeling of binary outcomes with application to aberrant crypt foci in colon carcinogenesis experiments  

E-print Network

, and as such it is not merely testing for a nuisance parameter. One way to test for such spatial dependence is to build a spatial regression model that includes independence as a special case, and then to test for this special case. 5 0 1 2 3 4 5 6 6 7 8 9 10 11 12 Figure 3. A...Z00klog(?00k)+Z01klog(?01k)+Z10klog(?10k)+Z11klog(?11k)g: (2.4) Formal difierentiation of (2.4) and evaluated at the null hypothesis ? = 0 would yield the essential part of the score statistic. Let dk be the Euclidean distance between the members...

Apanasovich, Tatiyana Vladimirovna

2005-11-01

203

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 ...

204

An Application of Induced Seismicity Data Analysis for Detection of Spatial Structures and Temporal Regimes of Deformation Processes in Hydrocarbon Fields  

Microsoft Academic Search

- An application of induced seismicity data to detection of deformation processes is considered. Methodology of the data interpretation is based on the conception of rock mass as a block medium adopting energy from internal and external sources and forming dissipative structures. The ideas from the stability theory of nonlinear systems are used. A spatial and temporal distribution of seismicity

S. B. Turuntaev; O. A. Razumnaya

2002-01-01

205

An Application of Induced Seismicity Data Analysis for Detection of Spatial Structures and Temporal Regimes of Deformation Processes in Hydrocarbon Fields  

Microsoft Academic Search

v--vAn application of induced seismicity data to detection of deformation processes is considered. Methodology of the data interpretation is based on the conception of rock mass as a block medium adopting energy from internal and external sources and forming dissipative structures. The ideas from the stability theory of nonlinear systems are used. A spatial and temporal distribution of seismicity is

S. B. Turuntaev; O. A. Razumnaya

2002-01-01

206

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

207

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

208

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

209

A spatial panel ordered-response model with application to the analysis of urban land-use development intensity patterns  

NASA Astrophysics Data System (ADS)

This paper proposes and estimates a spatial panel ordered-response probit model with temporal autoregressive error terms to analyze changes in urban land development intensity levels over time. Such a model structure maintains a close linkage between the land owner's decision (unobserved to the analyst) and the land development intensity level (observed by the analyst) and accommodates spatial interactions between land owners that lead to spatial spillover effects. In addition, the model structure incorporates spatial heterogeneity as well as spatial heteroscedasticity. The resulting model is estimated using a composite marginal likelihood (CML) approach that does not require any simulation machinery and that can be applied to data sets of any size. A simulation exercise indicates that the CML approach recovers the model parameters very well, even in the presence of high spatial and temporal dependence. In addition, the simulation results demonstrate that ignoring spatial dependency and spatial heterogeneity when both are actually present will lead to bias in parameter estimation. A demonstration exercise applies the proposed model to examine urban land development intensity levels using parcel-level data from Austin, Texas.

Ferdous, Nazneen; Bhat, Chandra R.

2013-01-01

210

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

211

Modeling spatial price transmission in the grain markets of Ethiopia with an application of ARDL approach to white teff  

Microsoft Academic Search

Following the agricultural market liberalization policy, there is an emerging grain market structure in Ethiopia in which the central wholesale market exhibits concentration of power and spatial integration with the local markets. Due to this, it is hypothesized that the central wholesale market influences the long-run price movements in the local markets. The relationship can be modeled as spatial price

Kindie Getnet; Wim Verbeke; Jacques Viaene

2005-01-01

212

Efficient vibrational state coupling in an optical tilted-washboard potential via multiple spatial translations and application to pulse echo  

E-print Network

We measure the application of simple and compound pulses consisting of time-dependent spatial translations to coupling vibrational states of ultracold 85Rb atoms in a far-detuned 1D optical lattice. The lattice wells are so shallow as to support only two bound states, and we prepare the atoms in the ground state. The lattice is oriented vertically, leading to a tilted-washboard potential analogous to those encountered in condensed-matter systems. Experimentally, we find that a square pulse consisting of lattice displacements and a delay is more efficient than single-step and Gaussian pulses. This is described as an example of coherent control. It is striking that contrary to the intuition that soft pulses minimize loss, the Gaussian pulse is outperformed by the square pulse. Numerical calculations are in strong agreement with our experimental results and show the superiority of the square pulse to the single-step pulse for all lattice depths and to the Gaussian pulse for lattice depths greater than 7 lattice recoil energies. We also compare the effectiveness of these pulses for reviving oscillations of atoms in vibrational superposition states using the pulse-echo technique. We find that the square and Gaussian pulses result in higher echo amplitudes than the single-step pulse. These improved echo pulses allow us to probe coherence at longer times than in the past, measuring a plateau which has yet to be explained. In addition, we show numerically that the vibrational state coupling due to such lattice manipulations is more efficient in shallow lattices than in deep lattices.

Samansa Maneshi; Jalani F. Kanem; Chao Zhuang; Matt Partlow; Aephraim M. Steinberg

2007-12-04

213

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

214

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

215

Interconnect Lifetime Prediction with Temporal and Spatial Temperature Gradients for Reliability-Aware Design and Runtime Management: Modeling and Applications  

E-print Network

Interconnect Lifetime Prediction with Temporal and Spatial Temperature Gradients for Reliability temperature gradients, we give close bounds in terms of uniformly distributed temperatures to estimate, temperature gradients, dynamic thermal/reliability man- agement.lectromigration, reliability-aware design

Skadron, Kevin

216

Spatial application of a cotton growth model for analysis of site-specific irrigation in the Texas High Plains  

E-print Network

, was tested for its ability to spatially calibrate soil water parameters of Cotton2k. The algorithm found multiple parameter sets for the same objective function results. This result runs contrary to expectations for the simulated annealing algorithm...

Clouse, Randy Wayne

2007-09-17

217

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.

Brida, Giorgio; Genovese, Marco; Rastello, Maria Luisa; Ruo-Berchera, Ivano

2010-01-01

218

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

219

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

220

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

221

Application of Inverse Path Distance Weighting for high-density spatial mapping of coastal water quality patterns  

E-print Network

One of the primary goals of coastal water quality monitoring is to characterize spatial variation. Generally, this monitoring takes place at a limited number of fixed sampling points. The alternative sampling methodology explored in this paper involves high density sampling from an onboard flow-through water analysis system (Dataflow). Dataflow has the potential to provide better spatial resolution of water quality features because it generates many closely spaced (< 10 m) measurements. Regardless of the measurement technique, parameter values at unsampled locations must be interpolated from nearby measurement points in order to generate a comprehensive picture of spatial variations. Standard Euclidean interpolations in coastal settings tend to yield inaccurate results because they extend through barriers in the landscape such as peninsulas, islands, and submerged banks. We recently developed a method for non-Euclidean interpolation by inverse path distance weighting (IPDW) in order to account for these ba...

Stachelek, Joseph

2015-01-01

222

Study of a high spatial resolution 10B-based thermal neutron detector for application in neutron reflectometry: the Multi-Blade prototype  

NASA Astrophysics Data System (ADS)

Although for large area detectors it is crucial to find an alternative to detect thermal neutrons because of the 3He shortage, this is not the case for small area detectors. Neutron scattering science is still growing its instruments' power and the neutron flux a detector must tolerate is increasing. For small area detectors the main effort is to expand the detectors' performances. At Institut Laue-Langevin (ILL) we developed the Multi-Blade detector which wants to increase the spatial resolution of 3He-based detectors for high flux applications. We developed a high spatial resolution prototype suitable for neutron reflectometry instruments. It exploits solid 10B-films employed in a proportional gas chamber. Two prototypes have been constructed at ILL and the results obtained on our monochromatic test beam line are presented here.

Piscitelli, F.; Buffet, J. C.; Clergeau, J. F.; Cuccaro, S.; Guérard, B.; Khaplanov, A.; La Manna, Q.; Rigal, J. M.; Van Esch, P.

2014-03-01

223

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

E-print Network

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

Song, Jae Young

2012-08-29

224

Calculation of spatial distribution of optical escape factor and its application to He I collisional-radiative model  

NASA Astrophysics Data System (ADS)

An integral analytical formula for a spatial distribution of the optical escape factor (OEF) in an infinite cylindrical plasma is derived as a function of an arbitrary upper state spatial density profile, the temperature ratio of the upper state to the lower state, and the optical depth of the corresponding transition. Test calculations are carried out for three different upper state profiles, i.e., uniform (rectangular), parabolic, and Gaussian upper state profiles. The OEF takes on negative values at the periphery of the parabolic and Gaussian upper state profiles. These characteristics cannot be expressed by the conventional OEF formulas derived for the center of the plasma, even though the optical depth is increased. In addition to the analytical derivation of the formula, two practical formulas are proposed: an empirical formula of the spatial distribution of the OEF for the Gaussian upper state density profile and a linear formula of the OEF distribution for upper state profiles that are expressed as linear combinations. These formulas enable us to calculate the spatial distribution of the OEF for the multiple-Gaussian upper state profile without the need for time-consuming integral calculations.

Iida, Yohei; Kado, Shinichiro; Tanaka, Satoru

2010-12-01

225

Calculation of spatial distribution of optical escape factor and its application to He I collisional-radiative model  

SciTech Connect

An integral analytical formula for a spatial distribution of the optical escape factor (OEF) in an infinite cylindrical plasma is derived as a function of an arbitrary upper state spatial density profile, the temperature ratio of the upper state to the lower state, and the optical depth of the corresponding transition. Test calculations are carried out for three different upper state profiles, i.e., uniform (rectangular), parabolic, and Gaussian upper state profiles. The OEF takes on negative values at the periphery of the parabolic and Gaussian upper state profiles. These characteristics cannot be expressed by the conventional OEF formulas derived for the center of the plasma, even though the optical depth is increased. In addition to the analytical derivation of the formula, two practical formulas are proposed: an empirical formula of the spatial distribution of the OEF for the Gaussian upper state density profile and a linear formula of the OEF distribution for upper state profiles that are expressed as linear combinations. These formulas enable us to calculate the spatial distribution of the OEF for the multiple-Gaussian upper state profile without the need for time-consuming integral calculations.

Iida, Yohei; Kado, Shinichiro; Tanaka, Satoru [School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2010-12-15

226

Fusion of Fuzzy Spatial Relations  

NASA Astrophysics Data System (ADS)

Spatial relations are essential for understanding the image configuration and modeling common sense knowledge. In most of existing methods, topological, directional and distance spatial relations are computed separately as they have separate application domains. Introduction of Temporal Geographic Information System (TGIS), spatio-temporal reasoning and study of spatio-temporal relations required the computation of topological and metric spatial relations together.

Salamat, Nadeem; Zahzah, El-Hadi

227

Influence of topical application of capsaicin, menthol and local anesthetics on intraoral somatosensory sensitivity in healthy subjects: temporal and spatial aspects.  

PubMed

The aim of this study was to investigate temporal and spatial aspects of somatosensory changes after topical application of capsaicin, menthol and local anesthetics (LA) on the gingiva with the use of intraoral palpometers and thermal devices. Sixteen healthy volunteers (eight male, eight female) participated. Four topical preparations (capsaicin, menthol, LA and Vaseline as a control) were randomly applied to the gingiva around the first premolar in the upper jaw via individual oral templates, which allowed spatial mapping of somatosensory changes at and adjacent to the site of application. The topical drugs were applied for 15 min in a randomized and balanced sequence. The perceived preparation-evoked pain intensity was recorded with the use of 0-10 visual analog scales (VAS). Standardized mechanical and thermal stimuli were applied before, during and up to 30 min after the topical applications, and numerical rating scales (NRS) were used to score the perceived intensity of the stimuli. Peak VAS, area under the curve and mean VAS preparation-evoked pain scores for capsaicin, menthol, LA and control were compared with paired t tests. NRS scores for mechanical and thermal test stimuli were analyzed with four-way repeated measurements analyses of variance. Capsaicin evoked significantly higher VAS pain parameters as well as higher NRS scores to heat stimuli than control (P < 0.029). There were no significant differences in stimulus-evoked NRS scores between the menthol and control conditions (P = 0.518), but LA caused significantly lower stimulus-evoked NRS scores compared with control (P < 0.001). Post hoc tests showed that capsaicin caused sensitization to heat stimuli at and adjacent to the application area. In conclusion, this study for the first time demonstrates the time course of capsaicin-evoked heat hyperalgesia in and outside the site of application at the oral mucosa (primary and secondary hyperalgesia). PMID:25596697

Naganawa, Takuya; Baad-Hansen, Lene; Ando, Tomohiro; Svensson, Peter

2015-04-01

228

Method and apparatus 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)

2004-01-01

229

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

230

Spatial grain size sorting in eolian ripples and estimation of wind conditions on planetary surfaces: Application to Meridiani Planum, Mars  

Microsoft Academic Search

The landscape seen by the Mars Exploration Rover (MER) Opportunity at Meridiani Planum is dominated by eolian (wind-blown) ripples with concentrated surface lags of hematitic spherules and fragments. These ripples exhibit profound spatial grain size sorting, with well-sorted coarse-grained crests and poorly sorted, generally finer-grained troughs. These ripples were the most common bed form encountered by Opportunity in its traverse

Douglas J. Jerolmack; David Mohrig; John P. Grotzinger; David A. Fike; Wesley A. Watters

2006-01-01

231

Spatial grain size sorting in eolian ripples and estimation of wind conditions on planetary surfaces: Application to Meridiani Planum, Mars  

Microsoft Academic Search

(1) The landscape seen by the Mars Exploration Rover (MER) Opportunity at Meridiani Planum is dominated by eolian (wind-blown) ripples with concentrated surface lags of hematitic spherules and fragments. These ripples exhibit profound spatial grain size sorting, with well-sorted coarse-grained crests and poorly sorted, generally finer-grained troughs. These ripples were the most common bed form encountered by Opportunity in its

Douglas J. Jerolmack; David Mohrig; John P. Grotzinger; David A. Fike; Wesley A. Watters

2006-01-01

232

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

233

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

234

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

235

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

236

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

237

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

238

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

239

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

240

Service Web de constitution en temps réel de mini-cubes SOLAP pour clients mobiles Une architecture orientée services pour l'utilisation mobile des données géo-décisionnelles  

Microsoft Academic Search

Existing Spatial OLAP (SOLAP) applications are targeted towards desktop computer environments. In order to enable geospatial decision support in mobility contexts, SOLAP requires some modifications. This paper describes a solution, based on service- oriented architectures and Web services technologies, designed to adapt SOLAP data cubes to the requirements and constraints encountered in mobile computing environments and wireless networks.

Etienne Dubé; Thierry Badard; Yvan Bédard

241

Une architecture orientée service Web pour la constitution de mini-cubes SOLAP pour clients mobiles  

Microsoft Academic Search

Existing Spatial OLAP (SOLAP) applications are targeted towards desktop c omputer environments. In order to enable geospatial decision support in mobility c ontexts, SOLAP re- quires some modifications. This paper describes a solution, based on se rvice-oriented architec- tures and Web services technologies, designed to adapt SOLAP data cub es to the requirements and constraints encountered in mobile computing environments

Etienne Dubé; Thierry Badard; Yvan Bédard

2008-01-01

242

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

243

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

244

Spatial Autocorrelation  

Microsoft Academic Search

In this chapter we review the concept of spatial autocorrelation and its attributes. Our purpose is to outline the various\\u000a formulations and measures of spatial autocorrelation and to point out how the concept helps assess the spatial nature of georeferenced\\u000a data. For a fuller treatment of the subject, a number of texts, written at various junctures in the development of

Arthur Getis

245

ADOPTION OF SPATIAL INFORMATION GATHERING TECHNOLOGIES AND VARIABLE RATE INPUT APPLICATION TECHNOLOGIES BY COTTON FARMERS IN THE SOUTHEAST  

Microsoft Academic Search

Probit analysis identified factors influencing adoption of precision farming technologies by Southeastern cotton farmers. Younger, more educated farmers who operated larger farms and were optimistic about the future of precision farming were most likely to adopt site-specific information technology. The probability of adopting variable rate input application technology was higher for younger farmers who operated larger farms, owned more of

Steven W. Martin; Roland K. Roberts; Burton C. English; James A. Larson; Rebecca L. Cochran; W. Robert Goodman; Sherry L. Larkin; Michele C. Marra; W. Donald Shurley; Jeanne M. Reeves

2004-01-01

246

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

E-print Network

of the major approaches in studying the genetics of the brain. In a classical twin study, heritability. Then, genetic modeling is performed using the classical twin design at each voxel, which provides with application to an fMRI study of twins Joonkoo Park a, , Kerby Shedden b , Thad A. Polk a a Department

247

An Application of Induced Seismicity Data Analysis for Detection of Spatial Structures and Temporal Regimes of Deformation Processes in Hydrocarbon Fields  

NASA Astrophysics Data System (ADS)

- An application of induced seismicity data to detection of deformation processes is considered. Methodology of the data interpretation is based on the conception of rock mass as a block medium adopting energy from internal and external sources and forming dissipative structures. The ideas from the stability theory of nonlinear systems are used. A spatial and temporal distribution of seismicity is analyzed to discover a regular, predictable component of seismic regime. Various methods were used for the analysis of seismic events listed in the seismic catalog in the region of Romashkino oil-field (Russia). Quasi-harmonious oscillations of seismic activity were found. They were synchronized in time with change of injection effectiveness. Spatial structures of seismicity were detected, and it was shown that these structures are in good agreement with tectonic faults. Data analysis shows correlation between seismic activity and imbalance of injected and extracted fluids. The obtained results show that water-injection effectiveness decreases during periods of increased seismic activity and increases during periods of low seismic activity.

Turuntaev, S. B.; Razumnaya, O. A.

248

Chapter J: Issues and challenges in the application of geostatistics and spatial-data analysis to the characterization of sand-and-gravel resources  

USGS Publications Warehouse

Sand-and-gravel (aggregate) resources are a critical component of the Nation's infrastructure, yet aggregate-mining technologies lag far behind those of metalliferous mining and other sectors. Deposit-evaluation and site-characterization methodologies are antiquated, and few serious studies of the potential applications of spatial-data analysis and geostatistics have been published. However, because of commodity usage and the necessary proximity of a mine to end use, aggregate-resource exploration and evaluation differ fundamentally from comparable activities for metalliferous ores. Acceptable practices, therefore, can reflect this cruder scale. The increasing use of computer technologies is colliding with the need for sand-and-gravel mines to modernize and improve their overall efficiency of exploration, mine planning, scheduling, automation, and other operations. The emergence of megaquarries in the 21st century will also be a contributing factor. Preliminary research into the practical applications of exploratory-data analysis (EDA) have been promising. For example, EDA was used to develop a linear-regression equation to forecast freeze-thaw durability from absorption values for Lower Paleozoic carbonate rocks mined for crushed aggregate from quarries in Oklahoma. Applications of EDA within a spatial context, a method of spatial-data analysis, have also been promising, as with the investigation of undeveloped sand-and-gravel resources in the sedimentary deposits of Pleistocene Lake Bonneville, Utah. Formal geostatistical investigations of sand-and-gravel deposits are quite rare, and the primary focus of those studies that have been completed is on the spatial characterization of deposit thickness and its subsequent effect on ore reserves. A thorough investigation of a gravel deposit in an active aggregate-mining area in central Essex, U.K., emphasized the problems inherent in the geostatistical characterization of particle-size-analysis data. Beyond such factors as common drilling methods jeopardizing the accuracy of the size-distribution curve, the application of formal geostatistical principles has other limitations. Many of the variables used in evaluating gravel deposits, including such sedimentologic parameters as sorting and such United Soil Classification System parameters as gradation coefficient, are nonadditive. Also, uniform sampling methods, such as drilling, are relatively uncommon, and sampling is generally accomplished by a combination of boreholes, water-well logs, test pits, trenches, stratigraphic columns from exposures, and, possibly, some geophysical cross sections. When evaluated in consideration of the fact that uniform mining blocks are also uncommon in practice, subsequent complexities in establishment of the volume/variance relation are inevitable. Several approaches exist to confront the limitations of geostatistical methods in evaluating sand-and-gravel deposits. Initially, we must acknowledge the practical requirements of the aggregate industry, as well as the limitations of the data collected by that industry, as a function of what the industry requires at the practical level, and consider that broader acceptance of formal geostatistics may require modifications of typical exploration and sampling protocols. Future investigations should utilize data from the full spectrum of sand-and-gravel deposits (flood plain, glacial, catastrophic flood, and marine), integrate such other disci plines as sedimentology and geophysics into the research, develop commodity-specific approaches to nonadditive variables, and include the results of comparative drilling.

Hack, Daniel R.

2005-01-01

249

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

250

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

251

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

252

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

253

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.

254

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

255

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

256

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

PubMed

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

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

2014-09-01

257

Spatial management of information  

Microsoft Academic Search

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

William C. Donelson

1978-01-01

258

A Plea for Spatial Literacy  

NSDL National Science Digital Library

This report from Nora Newcombe, which originally appeared in the Chronicle of Higher Education, looks at the importance of spatial reasoning. The author makes the argument that education in the United States should focus more heavily on improving student spatial skills, as these skills are widely applicable, particularly in respect to the STEM disciplines. She also discusses sex and socioeconomic differences in respect to spatial reasoning ability. This document may be downloaded in PDF file format.

Newcombe, Nora

259

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.

Nova Spatial LLC

260

Application of knowledge-driven spatial modelling approaches and uncertainty management to a study of Rift Valley fever in Africa  

PubMed Central

Background There are few studies that have investigated uncertainties surrounding the scientific community's knowledge of the geographical distribution of major animal diseases. This is particularly relevant to Rift Valley fever (RVF), a zoonotic disease causing destructive outbreaks in livestock and man, as the geographical range of the disease is widening to involve previously unaffected regions. In the current study we investigate the application of methods developed in the decision sciences: multiple criteria decision making using weighted linear combination and ordered weighted averages, and Dempster-Shafer theory, implemented within the geographical information system IDRISI, to obtain a greater understanding of uncertainty related to the geographical distribution of RVF. The focus is on presenting alternate methods where extensive field data are not available and traditional, model-based approaches to disease mapping are impossible to conduct. Results Using a compensatory multiple criteria decision making model based on weighted linear combination, most of sub-Saharan Africa was suitable for endemic circulation of RVF. In contrast, areas where rivers and lakes traversed semi-arid regions, such as those bordering the Sahara, were highly suitable for RVF epidemics and wet, tropical areas of central Africa had low suitability. Using a moderately non-compensatory model based on ordered weighted averages, the areas considered suitable for endemic and epidemic RVF were more restricted. Varying the relative weights of the different factors in the models did not affect suitability estimates to a large degree, but variations in model structure had a large impact on our suitability estimates. Our Dempster-Shafer analysis supported the belief that a range of semi-arid areas were suitable for RVF epidemics and the plausibility that many other areas of the continent were suitable. Areas where high levels of uncertainty were highlighted included the Ethiopian Highlands, southwest Kenya and parts of West Africa. Conclusion We have demonstrated the potential of methods developed in the decision sciences to improve our understanding of uncertainties surrounding the geographical distribution of animal diseases, particularly where information is sparse, and encourage wider application of the decision science methodology in the field of animal health. PMID:17156467

Clements, Archie CA; Pfeiffer, Dirk U; Martin, Vincent

2006-01-01

261

Remote sensing of aerosol optical depth from high spatial resolution images of HJ-1 constellation CCD sensors and application in the monitoring of environmental PM2.5  

NASA Astrophysics Data System (ADS)

The high spatial and temporal resolution of HJ-1 (The China Environment and Disasters Monitoring Microsatellite Constellation) makes it suitable for environment monitoring. However, due to lack the mid-infrared wavelength near 2.1?m, it is difficult to use HJ-1/CCD images to retrieve aerosol optical depth (AOD) which is one of the important parameters in environmental monitoring. Many currently widely used AOD products are from MODIS and retrieved using dark object method, which has great restriction for its accuracy when applied in urban areas. In this paper, we present a new algorithm which makes use of HJ1-CCD blue and green bands to retrieve AOD without using other auxiliary data. This method is based on the assumption that aerosol optical properties change quickly with time but slowly with location, and based on "Multi-wavelength, Multi-sensor, Multi-day" (3M) to achieve the signal separation between the atmosphere and the earth. A LUT (look-up table) is constructed using 6S RT (Radiative Transfer) code, then the minimum of a cost function is used to determine the aerosol optical thickness. This paper describes the result of remote sensing of aerosol optical thickness based on this method in different regions (Beijing-Tianjin-Tangshan, Yangtze River Delta, Pearl River Delta, etc.) and different spatial resolutions (100m, 500m, 1000m, etc.) in China. The retrieved AOD results are then used to predict PM2.5 mass concentration in these regions. The AOD and PM2.5 results are in good agreement with the measured results from sun photometers and PM2.5 particulate samplers, respectively, which shows that the method has good accuracy and applicability.

Yuhuan, Z.; Zhengqiang, L.; Weizhen, H.; Yan, M.; Ying, Z.; Ling, W.; Yang, L.; Yan, W.; Donghui, L.; Kaitao, L.; Yisong, X.

2012-12-01

262

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

263

GEO-RBAC: a spatially aware RBAC  

Microsoft Academic Search

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

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

2005-01-01

264

Applicability of the single equivalent point dipole model to represent a spatially distributed bio-electrical source  

NASA Technical Reports Server (NTRS)

Although the single equivalent point dipole model has been used to represent well-localised bio-electrical sources, in realistic situations the source is distributed. Consequently, position estimates of point dipoles determined by inverse algorithms suffer from systematic error due to the non-exact applicability of the inverse model. In realistic situations, this systematic error cannot be avoided, a limitation that is independent of the complexity of the torso model used. This study quantitatively investigates the intrinsic limitations in the assignment of a location to the equivalent dipole due to distributed electrical source. To simulate arrhythmic activity in the heart, a model of a wave of depolarisation spreading from a focal source over the surface of a spherical shell is used. The activity is represented by a sequence of concentric belt sources (obtained by slicing the shell with a sequence of parallel plane pairs), with constant dipole moment per unit length (circumferentially) directed parallel to the propagation direction. The distributed source is represented by N dipoles at equal arc lengths along the belt. The sum of the dipole potentials is calculated at predefined electrode locations. The inverse problem involves finding a single equivalent point dipole that best reproduces the electrode potentials due to the distributed source. The inverse problem is implemented by minimising the chi2 per degree of freedom. It is found that the trajectory traced by the equivalent dipole is sensitive to the location of the spherical shell relative to the fixed electrodes. It is shown that this trajectory does not coincide with the sequence of geometrical centres of the consecutive belt sources. For distributed sources within a bounded spherical medium, displaced from the sphere's centre by 40% of the sphere's radius, it is found that the error in the equivalent dipole location varies from 3 to 20% for sources with size between 5 and 50% of the sphere's radius. Finally, a method is devised to obtain the size of the distributed source during the cardiac cycle.

Armoundas, A. A.; Feldman, A. B.; Sherman, D. A.; Cohen, R. J.

2001-01-01

265

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

266

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.

267

The research progress of spatial data mining technique  

Microsoft Academic Search

More and more spatial data are used with the application and development of modern science and technique; therefore, obtaining the spatial knowledge becomes more and more important and meaningful. The tremendous amounts of spatial and non-spatial data have been stored in large spatial database. These are far beyond the human ability to interpret and analysis of them, which is urgently

Hailiang Jin; Baoliang Miao

2010-01-01

268

Combining spatial transition probabilities for stochastic simulation of categorical fields  

Microsoft Academic Search

Categorical spatial data, such as land use classes and socioeconomic statistics data, are important data sources in geographical information science (GIS). The investigation of spatial patterns implied in these data can benefit many aspects of GIS research, such as classification of spatial data, spatial data mining, and spatial uncertainty modeling. However, the discrete nature of categorical data limits the application

Guofeng Cao; Phaedon C. Kyriakidis; Michael F. Goodchild

2011-01-01

269

SHADYS (‘simulateur halieutique de dynamiques spatiales’), a GIS based numerical model of fisheries. Example application: The study of a marine protected area  

Microsoft Academic Search

This paper presents the simulator SHADYS (‘simulateur halieutique de dynamiques spatiales’). SHADYS is a tool devoted to the representation of spatial processes involved in fisheries dynamics. It puts together three fundamental entities in an explicit spatio-temporal way: the environment, the fish populations under consideration and the fishing fleet. It is based on simple, realistic and well identified mechanisms (density-dependent habitat

Olivier Maury; Didier Gascuel

1999-01-01

270

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

PubMed

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

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

2000-01-01

271

Accumulation and spatial distribution of Cd, Cr, and Pb in mulberry from municipal solid waste compost following application of EDTA and (NH4)2SO4.  

PubMed

Municipal solid waste compost can be used to cropland as soil amendment to supply nutrients and improve soil physical properties. But long-term application of municipal solid waste (MSW) compost may result in accumulation of toxic metals in amended soil. Phytoremediation, especially phytoextraction, is a novel, cost-effective, and environmentally friendly approach that uses metal-accumulating plants to concentrate and remove metals from contaminated soils. Ethylenediaminetetraacetate (EDTA) was applied to metal-contaminated soil to increase the mobility and phytoavailability of metals in soil, thereby increasing the amount of toxic metals accumulated in the upper parts of phytoextracting plants. The objectives of this study were (1) to investigate the accumulation and spatial distribution of toxic metals (Cd, Cr, and Pb) in mulberry from MSW compost with the application of EDTA and (NH(4))(2)SO(4), (2) to examine the effectiveness of EDTA and (NH(4))(2)SO(4) applied together on toxic metals (Cd, Cr, and Pb) removal by mulberry under field conditions, and (3) to evaluate the potential of mulberry for phytoextraction of toxic metals from MSW compost. The tested plant-mulberry had been grown in MSW compost field for 4 years. EDTA solution at five rates (0, 50, 100, 50 mmol L(-1) + 1 g L(-1) (NH(4))(2)SO(4), and 100 mmol L(-1) + 1 g L(-1) (NH(4))(2)SO(4)) was added into mulberry root medium in September 2009. Twenty days later, the plants were harvested and separated into six parts according to plant height. Cd, Cr, and Pb contents in plant samples and MSW compost were analyzed using an atomic absorption spectrophotometer. In the same treatment, Cd, Cr, and Pb concentrations in mulberry shoot were all higher than those in root, and Cd and Pb concentrations in shoot increased from lower to upper parts, reaching the highest in leaves. Significant increases were found in toxic metal concentration in different parts of mulberry with increasing EDTA concentration, especially when combined with (NH(4))(2)SO(4). Mulberry exhibited high ability to accumulate Cd with bioconcentration factors (BCFs) higher than 1. EDTA application also significantly increased Cd BCFs. More than 30 % of metal uptake was concentrated in mulberry branches (stem of above 100 cm height) and leaves. Results presented here show that mulberry is a woody plant that has the potential of Cd phytoextraction from MSW compost by removing leaves and cutting branches. The application of EDTA combined with (NH(4))(2)SO(4) significantly enhanced the efficiency of mulberry in removing Cd from the compost medium. Adding (NH(4))(2)SO(4) into the compost will lower the risk of the exposure of environment to excessive non-biodegradable EDTA in a large-scale EDTA-assisted phytoextraction by reducing the dosage of EDTA. In China, the need for sod is increasing day by day. Sod is often produced on arable soil and sold together with soils. This would lead to the soil being infertile and the soil layer thin. After several times' production, the soil can no longer be used for cultivating crops and be destroyed. In order to fully utilize MSW compost resources and save valuable soil resources, MSW compost can be used to replace arable soil to produce sod after extraction of toxic metals in it. PMID:22661279

Zhao, Shulan; Shang, Xiaojuan; Duo, Lian

2013-02-01

272

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

273

Fusion of Fuzzy Spatial Relations  

Microsoft Academic Search

\\u000a Spatial relations are essential for understanding the image configuration and modeling common sense knowledge. In most of\\u000a existing methods, topological, directional and distance spatial relations are computed separately as they have separate application\\u000a domains. Introduction of Temporal Geographic Information System (TGIS), spatio-temporal reasoning and study of spatio-temporal\\u000a relations required the computation of topological and metric spatial relations together.\\u000a \\u000a \\u000a In this

Nadeem Salamat; El-Hadi Zahzah

2010-01-01

274

A Geo-Additive Bayesian Discrete-Time Survival Model and its Application to Spatial Analysis of Childhood Mortality in Malawi  

Microsoft Academic Search

We describe a flexible geo-additive Bayesian survival model that controls, simultaneously, for spatial dependence and possible\\u000a nonlinear or time-varying effects of other variables. Inference is fully Bayesian and is based on recently developed Markov\\u000a Chain Monte Carlo techniques. In illustrating the model we introduce a spatial dimension in modelling under-five mortality\\u000a among Malawian children using data from Malawi Demographic and

Ngianga-Bakwin Kandala; Gebrenegus Ghilagaber

2006-01-01

275

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

276

Spatial Manipulation with Microfluidics  

PubMed Central

Biochemical gradients convey information through space, time, and concentration, and are ultimately capable of spatially resolving distinct cellular phenotypes, such as differentiation, proliferation, and migration. How these gradients develop, evolve, and function during development, homeostasis, and various disease states is a subject of intense interest across a variety of disciplines. Microfluidic technologies have become essential tools for investigating gradient sensing in vitro due to their ability to precisely manipulate fluids on demand in well-controlled environments at cellular length scales. This review will highlight their utility for studying gradient sensing along with relevant applications to biology.

Lin, Benjamin; Levchenko, Andre

2015-01-01

277

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

278

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

279

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

280

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

ERIC Educational Resources Information Center

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

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

281

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

282

Application of the micro-genetic algorithm to the design of spatial filters with frequency-selective surfaces embedded in dielectric media  

Microsoft Academic Search

We present an efficient method of optimizing spatial filters comprising of single and multiple frequency-selective surface (FSS) screens embedded in multilayered dielectric media. Two such filter designs are optimized via the micro-genetic algorithm (MGA) and their frequency responses are validated by alternate methods

Sourav Chakravarty; Raj Mittra

2002-01-01

283

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

284

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

285

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

PubMed

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

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

2008-05-15

286

Distance Oracles for Spatial Networks  

Microsoft Academic Search

Abstractó The popularity of location-based services and the need to do real-time processing on them has led to an interest in performing queries on transportation networks, such as nding shortest paths and nding nearest neighbors. The challenge is that these operations involve the computation of distance along a spatial network rather than ìas the crow ies. î In many applications

Jagan Sankaranarayanan; Hanan Samet

2009-01-01

287

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

288

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.

289

Spatially weighted supervised classification for remote sensing  

Microsoft Academic Search

A simple approach for incorporating a spatial weighting into a supervised classifier for remote sensing applications is presented. The classifier modifies the feature-space distance-based metric with a spatial weighting. This is facilitated by the use of a non-parametric (k-nearest neighbour, k-NN) classifier in which the spatial location of each pixel in the training data set is known and available for

Peter M. Atkinson

2004-01-01

290

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

291

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

Microsoft Academic Search

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

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

2005-01-01

292

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

NASA Astrophysics Data System (ADS)

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

Legleiter, Carl J.

2014-01-01

293

A Scan Statistic for Binary Outcome Based on Hypergeometric Probability Model, with an Application to Detecting Spatial Clusters of Japanese Encephalitis  

PubMed Central

As a useful tool for geographical cluster detection of events, the spatial scan statistic is widely applied in many fields and plays an increasingly important role. The classic version of the spatial scan statistic for the binary outcome is developed by Kulldorff, based on the Bernoulli or the Poisson probability model. In this paper, we apply the Hypergeometric probability model to construct the likelihood function under the null hypothesis. Compared with existing methods, the likelihood function under the null hypothesis is an alternative and indirect method to identify the potential cluster, and the test statistic is the extreme value of the likelihood function. Similar with Kulldorff’s methods, we adopt Monte Carlo test for the test of significance. Both methods are applied for detecting spatial clusters of Japanese encephalitis in Sichuan province, China, in 2009, and the detected clusters are identical. Through a simulation to independent benchmark data, it is indicated that the test statistic based on the Hypergeometric model outweighs Kulldorff’s statistics for clusters of high population density or large size; otherwise Kulldorff’s statistics are superior. PMID:23785424

Zhao, Xing; Zhou, Xiao-Hua; Feng, Zijian; Guo, Pengfei; He, Hongyan; Zhang, Tao; Duan, Lei; Li, Xiaosong

2013-01-01

294

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

295

Building Analysis from a Spatial Cognition Perspective  

E-print Network

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

296

A spatially explicit risk approach to support marine spatial planning in the German EEZ.  

PubMed

An ecosystem approach to marine spatial planning (MSP) promotes sustainable development by organizing human activities in a geo-spatial and temporal context. (1) This study develops and tests a spatially explicit risk assessment to support MSP. Using the German exclusive economic zone (EEZ) of the North Sea as a case study area, current and future spatial management scenarios are assessed. (2) Different tools are linked in order to carry out a comprehensive spatial risk assessment of current and future spatial management scenarios for ecologic and economic ecosystem components, i.e. Pleuronectes platessa nursery grounds. With the identification of key inputs and outputs the suitability of each tool is tested. (3) Here, the procedure as well as the main findings of the spatially explicit risk approach are summarised to demonstrate the applicability of the framework and the need for an ecosystem approach to risk management techniques using geo-spatial tools. PMID:23535014

Gimpel, Antje; Stelzenmüller, Vanessa; Cormier, Roland; Floeter, Jens; Temming, Axel

2013-05-01

297

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

EPA Science Inventory

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

298

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

299

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

300

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.

301

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.

302

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

303

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

304

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

PubMed

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

Saito, Hirotaka; McKenna, Sean A

2007-07-01

305

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

306

Merging Hypermedia GIS with Spatial On-Line Analytical Processing: Towards Hypermedia SOLAP  

E-print Network

Systems (GIS) with those of On-Line Analytical Processing (OLAP), paving the way to a new technology(s)), Geographic Hypermedia: Concepts and Systems . accepté #12;information adheres to the way human brains think, charts or photographs), videos, sounds (music and oral narration) and animations (changing maps, objects a

307

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

308

Jackpine: A benchmark to evaluate spatial database performance  

Microsoft Academic Search

The volume of spatial data generated and consumed is rising exponentially and new applications are emerging as the costs of storage, processing power and network bandwidth continue to decline. Database support for spatial operations is fast becoming a necessity rather than a niche feature provided by a few products. However, the spatial functionality offered by current commercial and open-source relational

Suprio Ray; Bogdan Simion; Angela Demke Brown

2011-01-01

309

OPENGIS BASED WIRELESS SPATIAL DATA LOGGER FOR FLOOD MITIGATION  

Microsoft Academic Search

Database Management Systems (DBMS) plays an important role for decision-making and mitigating disaster events such as floods. With ever increasing challenges in spatially-related managing and decision making applications, wired GIS cannot meet the demands of users for easy access to spatial data and spatial analysis. For disaster mitigation, data needs to be uploaded and retrieved from the field to minimize

Nitin K. Tripathi; Vasan Choengsa-ard

2005-01-01

310

ACO based spatial data mining for traffic risk analysis  

Microsoft Academic Search

Many organizations have collected large amounts of spatially referenced data in various application areas such as geographic information systems (GIS), banking and retailing. These are valuable mines of knowledge vital for strategic decision making and motivate the highly demanding field of spatial data mining i.e., discovery of interesting, implicit knowledge from large amounts of spatial data. Most government local administrations

K. Ravikumar; A. Gnanabaskaran

2010-01-01

311

QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL  

E-print Network

QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL I. Chaubey, C. T. Haan in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous induced in model outputs solely due to rainfall spatial variability. The study was conducted using

Grunwald, Sabine

312

Investigating the spatial micro-epidemiology of diseases within a point-prevalence sample: a field applicable method for rapid mapping of households using low-cost GPS-dataloggers  

PubMed Central

Summary Point-prevalence recording of the distribution of tropical parasitic diseases at village level is usually sufficient for general monitoring and surveillance. Whilst within-village spatial patterning of diseases exists, and can be important, mapping infected cases in a household-by-household setting is arduous and time consuming. With the development of low-cost GPS-data loggers (< £40) and available GoogleEarthTM satellite imagery, we present a field-applicable method based on crowdsourcing for rapid identification of infected cases (intestinal schistosomiasis, malaria and hookworm) by household. A total of 126 mothers with their 247 preschool children from Bukoba village (Mayuge District, Uganda) were examined with half of these mothers given a GPS-data logger to walk home with, returning the unit the same day for data off-loading, after which, households were assigned GPS coordinates. A satellite image of Bukoba was annotated with households denoting the infection status of each mother and child. General prevalence of intestinal schistosomiasis, malaria and hookworm in mothers and children was: 27.2 vs 7.7%, 28.6 vs 87.0% and 60.0 vs 22.3%, respectively. Different spatial patterns of disease could be identified likely representing the intrinsic differences in parasite biology and interplay with human behaviour(s) across this local landscape providing a better insight into reasons for disease micro-patterning. PMID:21714979

Stothard, J. Russell; Sousa-Figueiredo, Jose C.; Betson, Martha; Seto, Edmund Y.W.; Kabatereine, Narcis B.

2011-01-01

313

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

314

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

315

Projecting land use transitions at forest fringes in the Philippines at two spatial scales  

Microsoft Academic Search

This paper presents two applications of a spatially explicit model of land use change at two spatial scales: a nation-wide application for the Philippines at relatively coarse resolution and an application with high spatial resolution for one island of the Philippines: Sibuyan island, Romblon province. The model is based on integrated analysis of socio-economic and biophysical factors that determine the

Peter H. Verburg; A. Veldkamp

2004-01-01

316

Cooperative Caching for Grid Based DataWarehouses  

Microsoft Academic Search

Abstract In this paper we propose a grid-based OLAP application which distributes query computation,across an enterprise grid. Our application follows a two-tiered process for answering queries based on sharing cached OLAP data between the users at the local grid site, and using grid scheduling approaches to execute the remaining parts of a query amongst,a distributed set of OLAP servers. A

Frank K. H. A. Dehne; Michael Lawrence; Andrew Rau-Chaplin

2007-01-01

317

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

318

Development of atomic radical monitoring probe and its application to spatial distribution measurements of H and O atomic radical densities in radical-based plasma processing  

SciTech Connect

Atomic radicals such as hydrogen (H) and oxygen (O) play important roles in process plasmas. In a previous study, we developed a system for measuring the absolute density of H, O, nitrogen, and carbon atoms in plasmas using vacuum ultraviolet absorption spectroscopy (VUVAS) with a compact light source using an atmospheric pressure microplasma [microdischarge hollow cathode lamp (MHCL)]. In this study, we developed a monitoring probe for atomic radicals employing the VUVAS with the MHCL. The probe size was 2.7 mm in diameter. Using this probe, only a single port needs to be accessed for radical density measurements. We successfully measured the spatial distribution of the absolute densities of H and O atomic radicals in a radical-based plasma processing system by moving the probe along the radial direction of the chamber. This probe allows convenient analysis of atomic radical densities to be carried out for any type of process plasma at any time. We refer to this probe as a ubiquitous monitoring probe for atomic radicals.

Takahashi, Shunji [Department of Electrical Engineering and Computer Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Katagiri Engineering Co., Ltd., 3-5-34 Shitte Tsurumi-ku, Yokohama 230-0003 (Japan); Takashima, Seigo [Plasma Center for Industrial Applications, Nagoya Urban Industries Promotion Corporation, 2268-1 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-0003 (Japan); Yamakawa, Koji; Den, Shoji [Katagiri Engineering Co., Ltd., 3-5-34 Shitte Tsurumi-ku, Yokohama 230-0003 (Japan); Kano, Hiroyuki [NU-EcoEngineering Co., Ltd., 1237-87 Aza Umazutsumi, Ooaza Kurozasa, Miyoshi-cho, Nishikamo-gun, Aichi 470-0201 (Japan); Takeda, Keigo [Department of Electrical Engineering and Computer Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Hori, Masaru [Department of Electrical Engineering and Computer Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Plasma Nanotechnology Research Center, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); JST, CREST, 4-1-8 Hon-chou, Kawaguchi, Saitama 332-0012 (Japan)

2009-09-01

319

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

320

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

321

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

322

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

323

Application of Multi-Criteria Decision Analysis to Geoelectric and Geologic Parameters for Spatial Prediction of Groundwater Resources Potential and Aquifer Evaluation  

NASA Astrophysics Data System (ADS)

Prediction of groundwater resources potential is a spatial decision problem that involves a set of multiple evaluation parameters. In order to produce a groundwater resources potential prediction model of higher reliability and precision in a given study area, the effects of all the important parameters that can contribute to the groundwater occurrence in the area must be integrated. However, the methodology of integrating these parameters such that the relative importance of each is reflected is still a challenge that has not been efficiently handled. In this study, the principle of multi-criteria decision analysis in the context of the analytical hierarchy process is proposed as a technique that can yield a prediction model of higher reliability and precision. The proposed technique was applied to geoelectric and geologic parameters, derived from the results of the interpretation of 2D resistivity imaging data acquired from the study area. The advantage of the proposed technique is that it reduces bias in decision making. The main objective of the study is to produce groundwater potential map for the area. Furthermore, an attempt was also made in the study to characterize the aquifer of the area by estimating the Dar-Zarrouk parameters, using the integration of borehole and 2D resistivity data. The success rate (accuracy) of the prediction was established to be 80 %. Furthermore, the regression line fitted to the aquifer transmissivity and transverse resistance data shows linear relationship with a high regression coefficient of 0.79. The prediction success rate obtained showed that the method proposed in this study is reliable, accurate, and an improved technique of integrating multiple parameters for holistic evaluation of groundwater resources.

Adiat, K. A. N.; Nawawi, M. N. M.; Abdullah, K.

2013-03-01

324

Detecting of transient vibration signatures using an improved fast spatial-spectral ensemble kurtosis kurtogram and its applications to mechanical signature analysis of short duration data from rotating machinery  

NASA Astrophysics Data System (ADS)

Detecting transient vibration signatures is of vital importance for vibration-based condition monitoring and fault detection of the rotating machinery. However, raw mechanical signals collected by vibration sensors are generally mixtures of physical vibrations of the multiple mechanical components installed in the examined machinery. Fault-generated incipient vibration signatures masked by interfering contents are difficult to be identified. The fast kurtogram (FK) is a concise and smart gadget for characterizing these vibration features. The multi-rate filter-bank (MRFB) and the spectral kurtosis (SK) indicator of the FK are less powerful when strong interfering vibration contents exist, especially when the FK are applied to vibration signals of short duration. It is encountered that the impulsive interfering contents not authentically induced by mechanical faults complicate the optimal analyzing process and lead to incorrect choosing of the optimal analysis subband, therefore the original FK may leave out the essential fault signatures. To enhance the analyzing performance of FK for industrial applications, an improved version of fast kurtogram, named as "fast spatial-spectral ensemble kurtosis kurtogram", is presented. In the proposed technique, discrete quasi-analytic wavelet tight frame (QAWTF) expansion methods are incorporated as the detection filters. The QAWTF, constructed based on dual tree complex wavelet transform, possesses better vibration transient signature extracting ability and enhanced time-frequency localizability compared with conventional wavelet packet transforms (WPTs). Moreover, in the constructed QAWTF, a non-dyadic ensemble wavelet subband generating strategy is put forward to produce extra wavelet subbands that are capable of identifying fault features located in transition-band of WPT. On the other hand, an enhanced signal impulsiveness evaluating indicator, named "spatial-spectral ensemble kurtosis" (SSEK), is put forward and utilized as the quantitative measure to select optimal analyzing parameters. The SSEK indicator is robuster in evaluating the impulsiveness intensity of vibration signals due to its better suppressing ability of Gaussian noise, harmonics and sporadic impulsive shocks. Numerical validations, an experimental test and two engineering applications were used to verify the effectiveness of the proposed technique. The analyzing results of the numerical validations, experimental tests and engineering applications demonstrate that the proposed technique possesses robuster transient vibration content detecting performance in comparison with the original FK and the WPT-based FK method, especially when they are applied to the processing of vibration signals of relative limited duration.

Chen, BinQiang; Zhang, ZhouSuo; Zi, YanYang; He, ZhengJia; Sun, Chuang

2013-10-01

325

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

NASA Astrophysics Data System (ADS)

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

Wang, J.; Cai, X.

2007-12-01

326

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

327

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

328

Swarm-Based Spatial Sorting  

E-print Network

Purpose: To present an algorithm for spatially sorting objects into an annular structure. Design/Methodology/Approach: A swarm-based model that requires only stochastic agent behaviour coupled with a pheromone-inspired "attraction-repulsion" mechanism. Findings: The algorithm consistently generates high-quality annular structures, and is particularly powerful in situations where the initial configuration of objects is similar to those observed in nature. Research limitations/implications: Experimental evidence supports previous theoretical arguments about the nature and mechanism of spatial sorting by insects. Practical implications: The algorithm may find applications in distributed robotics. Originality/value: The model offers a powerful minimal algorithmic framework, and also sheds further light on the nature of attraction-repulsion algorithms and underlying natural processes.

Amos, Martyn

2008-01-01

329

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

330

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

PubMed Central

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, Ángel; Guzmán, José; Oria, Javier; González, Luis Mariano; Margalida, Antoni

2011-01-01

331

Parcellating connectivity in spatial maps  

PubMed Central

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

Beck, Diane M.; Fei-Fei, Li

2015-01-01

332

Robustness of Spatial Micronetworks  

E-print Network

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

McAndrew, Thomas C; Bagrow, James P

2015-01-01

333

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

334

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

335

Individual differences in spatial text processing: High spatial ability can compensate for spatial working memory interference  

Microsoft Academic Search

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. To understand how individuals who differ

Chiara Meneghetti; Valérie Gyselinck; Francesca Pazzaglia; Rossana De Beni

2009-01-01

336

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

337

Ranking in Spatial Databases  

Microsoft Academic Search

. An algorithm for ranking spatial objects according to increasingdistance from a query object is introduced and analyzed. Thealgorithm makes use of a hierarchical spatial data structure. The intendedapplication area is a database environment, where the spatialdata structure serves as an index. The algorithm is incremental in thesense that objects are reported one by one, so that a query processor

Gísli R. Hjaltason; Hanan Samet

1995-01-01

338

Geography and Spatial Planning  

E-print Network

Master in Geography and Spatial Planning ­ Master académique #12;University of Luxembourg, Philosophy, Sociology, Geography, Language and Literature. The Faculty is composed of four interdisciplinary in Geography and Spatial Planning at the University of Luxembourg. Making room for geographical thinking is key

van der Torre, Leon

339

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

340

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

341

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

342

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

343

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

344

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

PubMed

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

345

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

NASA Astrophysics Data System (ADS)

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.

Zhu, Long; Wang, Jian

2014-12-01

346

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

347

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

348

Centre National d'Etudes Spatiales  

NASA Astrophysics Data System (ADS)

The Centre National d'Etudes Spatiales (CNES) draws up, proposes and conducts France's space policy. Its role is to develop the uses of space, to meet the civilian and military needs of public bodies and of the scientific community, and to foster the development and dissemination of new applications, designed to create wealth and jobs....

Murdin, P.

2000-11-01

349

Chapter 13 Geovisualization 179 Spatial Data Analysis  

E-print Network

;Chapter 13 Geovisualization 180 tolerance, Thiessen polygons, Inverse-distance weighting (IDW), Kriging constructed around the concepts of location, distance, and area LEARNING OBJECTIVES Definitions of spatial to examine distance effects, in the creation of clusters, hotspots, and anomalies. The applications

Wright, Dawn Jeannine

350

Spatial Outsourcing for Location-based Services  

Microsoft Academic Search

The embedding of positioning capabilities in mobile devices and the emergence of location-based applications have created novel opportunities for utilizing several types of multi- dimensional data through spatial outsourcing. In this setting, a data owner (DO) delegates its data management tasks to a location-based service (LBS) that processes queries originating from several clients\\/ subscribers. Because the LBS is not the

Yin Yang; Stavros Papadopoulos; Dimitris Papadias; George Kollios

2008-01-01

351

Visualizing spatial data uncertainty using animation  

Microsoft Academic Search

This paper examines methodologies for dynamically displaying information about uncertainty. Modeling uncertainty in elevation data results in the generation of dozens or hundreds of realizations of the elevation surface. Producing animations of these surfaces is an approach to exploratory data visualization that may assist the researcher in understanding the effect of uncertainty on spatial applications as well as in communicating

Charles R. Ehlschlaeger; Ashton M. Shortridge; Michael F. Goodchild

1997-01-01

352

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

353

Efficiently Matching Proximity Relationships in Spatial Databases  

E-print Network

of real applications, such as real-estate marketing, urban planning, weather fore- casting, medical image, weather pattern analysis, urban plan- ning, transportation management, etc. While processing of typicalEfficiently Matching Proximity Relationships in Spatial Databases Xuemin Lin1 , Xiaomei Zhou1

Lin, Xuemin

354

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 ...

355

Tailoring spatial reference in early warning systems to administrative units  

Microsoft Academic Search

This paper presents a novel approach for early warning systems to transform the spatial reference of dispersion models into\\u000a addressable administrative units enabling an intelligible warning message reception and spatial awareness. The spatial reference\\u000a along the entire information chain from sensor measurements via dispersion model to warning dissemination is discussed. Core\\u000a concept behind this approach is the application of the

Matthias Lendholt

2011-01-01

356

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.

357

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

358

ET Spatial Techniques  

NSDL National Science Digital Library

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

ET Spatial Techniques

359

Querying Spatial Databases via Topological Invariants Luc Segou n  

E-print Network

is on the translation of topological queries against the spatial database into queries against the topological invariant queries on topological invariants. 1 Introduction Spatial data is an increasingly important part databases, medical imaging, CAD-CAM, VLSI, robotics, etc. Di erent applications pose di erent requirements

Segoufin, Luc

360

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

361

Modeling and estimating the spatial distribution of healthcare workers  

Microsoft Academic Search

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

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

2010-01-01

362

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

363

Distance in spatial interpolation of daily rain gauge data  

Microsoft Academic Search

Spatial interpolation of rain gauge data is important in forcing of hydrological simulations or evaluation of weather predictions, for example. The spatial density of available data sites is often changing with time. This paper investigates the application of statistical distance, like one minus common variance of time series, between data sites instead of geographical distance in interpolation. Here, as a

B. Ahrens

2005-01-01

364

Spatially varying dynamical properties of turbid media probed with  

E-print Network

Spatially varying dynamical properties of turbid media probed with diffusing temporal light in turbid media and is accurately modeled by a correlation diffusion equation. We demonstrate ex of the spatially varying dynamical properties of turbid media. The biomedical applicability of this diffuse

365

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...

366

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

367

Site characterization: a spatial estimation approach  

SciTech Connect

In this report the application of spatial estimation techniques or kriging to groundwater aquifers and geological borehole data is considered. The adequacy of these techniques to reliably develop contour maps from various data sets is investigated. The estimator is developed theoretically in a simplified fashion using vector-matrix calculus. The practice of spatial estimation is discussed and the estimator is then applied to two groundwater aquifer systems and used also to investigate geological formations from borehole data. It is shown that the estimator can provide reasonable results when designed properly.

Candy, J.V.; Mao, N.

1980-10-01

368

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

369

Cooperative Caching for Grid Based Data Warehouses  

Microsoft Academic Search

In this paper we propose a grid-based OLAP applica- tion which distributes query computation across an enter- prise grid. Our application follows a two-tiered process for answering queries based on sharing cached OLAP data between the users at the local grid site, and using grid scheduling approaches to execute the remaining parts of a query amongst a distributed set of

Frank Dehne; Michael Lawrence; Andrew Rau-Chaplin

370

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

371

Adaptation to spatial offsets.  

PubMed

After prolonged viewing of a three-element target in which the middle element is spatially offset, subsequent viewing of the same three elements in alignment results in the middle element appearing to be offset in the opposite direction. This adaptational aftereffect to a spatial offset was investigated with elements which were spatial-frequency narrowband and equidetectable to ascertain (a) the properties of the mechanisms involved and (b) the nature of the underlying computation. Evidence is presented in favour of an orientational-grouping, rather than a purely positional computation, underlying this aftereffect. A dual site of adaptation is proposed: one which receives input from the orientation extracted from the output of linear filters, and another which receives input from the orientation derived from grouping processes working on the contrast-energy representation. These may correspond to the mechanisms which are thought to underlie the processing of real and subjective contours. PMID:8734541

Hess, R F; Doshi, S

1995-01-01

372

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.

373

Perceptual categories for spatial layout.  

PubMed

The central problems of vision are often divided into object identification and localization. Object identification, at least at fine levels of discrimination, may require the application of top-down knowledge to resolve ambiguous image information. Utilizing top-down knowledge, however, may require the initial rapid access of abstract object categories based on low-level image cues. Does object localization require a different set of operating principles than object identification or is category determination also part of the perception of depth and spatial layout? Three-dimensional graphics movies of objects and their cast shadows are used to argue that identifying perceptual categories is important for determining the relative depths of objects. Processes that can identify the causal class (e.g. the kind of material) that generates the image data can provide information to determine the spatial relationships between surfaces. Changes in the blurriness of an edge may be characteristically associated with shadows caused by relative motion between two surfaces. The early identification of abstract events such as moving object/shadow pairs may also be important for depth from shadows. Knowledge of how correlated motion in the image relates to an object and its shadow may provide a reliable cue to access such event categories. PMID:9304683

Kersten, D

1997-08-29

374

The importance of scale for spatial-confounding bias and precision of spatial regression estimators  

PubMed Central

Residuals in regression models are often spatially correlated. Prominent examples include studies in environmental epidemiology to understand the chronic health effects of pollutants. I consider the effects of residual spatial structure on the bias and precision of regression coefficients, developing a simple framework in which to understand the key issues and derive informative analytic results. When unmeasured confounding introduces spatial structure into the residuals, regression models with spatial random effects and closely-related models such as kriging and penalized splines are biased, even when the residual variance components are known. Analytic and simulation results show how the bias depends on the spatial scales of the covariate and the residual: one can reduce bias by fitting a spatial model only when there is variation in the covariate at a scale smaller than the scale of the unmeasured confounding. I also discuss how the scales of the residual and the covariate affect efficiency and uncertainty estimation when the residuals are independent of the covariate. In an application on the association between black carbon particulate matter air pollution and birth weight, controlling for large-scale spatial variation appears to reduce bias from unmeasured confounders, while increasing uncertainty in the estimated pollution effect. PMID:21528104

Paciorek, Christopher J

2010-01-01

375

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

376

Spatial filter issues  

SciTech Connect

Beamlet measurements show that cone pinholes outperform other types tested with regard to both closure and back reflections. A ±150 µrad stainless steel cone remained open for a 15.5 kJ, 10:1 contrast shaped pulse with ±7.5 µrad of SSD divergence, which more than meets the requirements for a NIF ignition pulse. Measurements also showed the maximum tolerable pressures in the NIF spatial filters to be a few milliTorr, leading to recommendations of 0.1 and 0.6 mTorr for the NIF transport and cavity spatial filters, respectively.

Boley, C. D.; Bonneau, F.; Estabrook, K. G.; Milam, D.; Murray, J. E.

1998-07-23

377

Hierarchical Modeling for Spatial Data Problems.  

PubMed

This short paper is centered on hierarchical modeling for problems in spatial and spatio-temporal statistics. It draws its motivation from the interdisciplinary research work of the author in terms of applications in the environmental sciences - ecological processes, environmental exposure, and weather modeling. The paper briefly reviews hierarchical modeling specification, adopting a Bayesian perspective with full inference and associated uncertainty within the specification, while achieving exact inference to avoid what may be uncomfortable asymptotics. It focuses on point-referenced (geo-statistical) and point pattern spatial settings. It looks in some detail at problems involving data fusion, species distributions, and large spatial datasets. It also briefly describes four further examples arising from the author's recent research projects. PMID:24010050

Gelfand, Alan E

2012-05-01

378

Spatial cluster detection using dynamic programming  

PubMed Central

Background The task of spatial cluster detection involves finding spatial regions where some property deviates from the norm or the expected value. In a probabilistic setting this task can be expressed as finding a region where some event is significantly more likely than usual. Spatial cluster detection is of interest in fields such as biosurveillance, mining of astronomical data, military surveillance, and analysis of fMRI images. In almost all such applications we are interested both in the question of whether a cluster exists in the data, and if it exists, we are interested in finding the most accurate characterization of the cluster. Methods We present a general dynamic programming algorithm for grid-based spatial cluster detection. The algorithm can be used for both Bayesian maximum a-posteriori (MAP) estimation of the most likely spatial distribution of clusters and Bayesian model averaging over a large space of spatial cluster distributions to compute the posterior probability of an unusual spatial clustering. The algorithm is explained and evaluated in the context of a biosurveillance application, specifically the detection and identification of Influenza outbreaks based on emergency department visits. A relatively simple underlying model is constructed for the purpose of evaluating the algorithm, and the algorithm is evaluated using the model and semi-synthetic test data. Results When compared to baseline methods, tests indicate that the new algorithm can improve MAP estimates under certain conditions: the greedy algorithm we compared our method to was found to be more sensitive to smaller outbreaks, while as the size of the outbreaks increases, in terms of area affected and proportion of individuals affected, our method overtakes the greedy algorithm in spatial precision and recall. The new algorithm performs on-par with baseline methods in the task of Bayesian model averaging. Conclusions We conclude that the dynamic programming algorithm performs on-par with other available methods for spatial cluster detection and point to its low computational cost and extendability as advantages in favor of further research and use of the algorithm. PMID:22443103

2012-01-01

379

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

380

Trellis Coded Spatial Modulation  

Microsoft Academic Search

Trellis coded modulation (TCM) is a well known scheme that reduces power requirements without any bandwidth expansion. In TCM, only certain sequences of successive constellation points are allowed (mapping by set partitioning). The novel idea in this paper is to apply the TCM concept to the antenna constellation points of spatial modulation (SM). The aim is to enhance SM performance

Raed Mesleh; Marco Di Renzo; Harald Haas; Peter M. Grant

2010-01-01

381

Spatial Terahertz Modulator  

NASA Astrophysics Data System (ADS)

Terahertz (THz) technology is a developing and promising candidate for biological imaging, security inspection and communications, due to the low photon energy, the high transparency and the broad band properties of the THz radiation. However, a major encountered bottleneck is lack of efficient devices to manipulate the THz wave, especially to modulate the THz wave front. A wave front modulator should allow the optical or electrical control of the spatial transmission (or reflection) of an input THz wave and hence the ability to encode the information in a wave front. Here we propose a spatial THz modulator (STM) to dynamically control the THz wave front with photo-generated carriers. A computer generated THz hologram is projected onto a silicon wafer by a conventional spatial light modulator (SLM). The corresponding photo-generated carrier spatial distribution will be induced, which forms an amplitude hologram to modulate the wave front of the input THz beam. Some special intensity patterns and vortex beams are generated by using this method. This all-optical controllable STM is structure free, high resolution and broadband. It is expected to be widely used in future THz imaging and communication systems.

Xie, Zhenwei; Wang, Xinke; Ye, Jiasheng; Feng, Shengfei; Sun, Wenfeng; Akalin, Tahsin; Zhang, Yan

2013-11-01

382

Chunking in Spatial Memory  

ERIC Educational Resources Information Center

In order to gain insight into the nature of human spatial representations, the current study examined how those representations are affected by blind rotation. Evidence was sought on the possibility that whereas certain environmental aspects may be updated independently of one another, other aspects may be grouped (or chunked) together and updated…

Sargent, Jesse; Dopkins, Stephen; Philbeck, John; Chichka, David

2010-01-01

383

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...

384

Diagonal spatial neglect  

PubMed Central

OBJECTIVE—To determine whether stroke patients with diagonal neglect on cancellation may show diagonal neglect on line bisection, and hence to indicate whether diagonal neglect may be related solely to the type of test used or whether instead it may reflect a fundamental spatial disorder.?METHODS—Nine patients with subacute right hemispheric stroke who neglected targets primarily in the near left direction on line cancellation bisected diagonal lines of two opposing orientations: near left to far right and far left to near right. The errors were assessed to determine whether line orientation significantly affected bisection error.?RESULTS—Eight patients had significant bisection errors. One of these showed no effect of line orientation on error, consistent with lateral neglect. The remaining seven patients had a line orientation effect, indicating a net diagonal spatial bias. For the group, cancellation errors were significantly correlated with the line orientation effect on bisection errors.?CONCLUSIONS—A significant diagonal bias on two tests of spatial attention may appear in stroke patients, although the directions of the biases may differ within individual patients. None the less, diagonal neglect may be a fundamental spatial attentional disturbance of right hemispheric stroke. Greater severity of stroke deficit as indicated by cancellation error score may be associated with a greater degree of diagonal neglect on line bisection.?? PMID:9728947

Mark, V.; Heilman, K.

1998-01-01

385

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

386

Grounded spatial belief revision.  

PubMed

Beliefs frequently undergo revisions, especially when new pieces of information are true but inconsistent with current beliefs. In previous studies, we showed that linguistic asymmetries provided by relational statements, play a crucial role in spatial belief revision. Located objects (LO) are preferably revised compared to reference objects (RO), known as the LO-principle. Here we establish a connection between spatial belief revision and grounded cognition. In three experiments, we explored whether imagined physical object properties influence which object is relocated and which remains at its initial position. Participants mentally revised beliefs about the arrangements of objects which could be envisaged as light and heavy (Experiment 1), small and large (Experiment 2), or movable and immovable (Experiment 3). The results show that intrinsic object properties are differently taken into account during spatial belief revision. Object weight did not alter the LO-principle (Experiment 1), whereas object size was found to influence which object was preferably relocated (Experiment 2). Object movability did not affect relocation preferences but had an effect on relocation durations (Experiment 3). The findings support the simulation hypothesis within the grounded cognition approach and create new connections between the spatial mental model theory of reasoning and the idea of grounded cognition. PMID:25796056

Nejasmic, Jelica; Bucher, Leandra; Knauff, Markus

2015-05-01

387

Infrared Spatial Interferometer  

Microsoft Academic Search

THe IR Spatial Interferometer (ISI) is an interferometer installed on Mt. Wilson and operating in the 10 micrometers wavelength region, using heterodyne detection and two movable 1.65 m telescopes. Its general technology and characteristics, recent changes, and observational results are broadly discussed. Some compensation for atmospheric path length fluctuations is demonstrated. Stellar observations show, among other characteristics, that many stars

Charles H. Townes; Manfred Bester; William C. Danchi; D. D. Hale; John D. Monnier; Everett A. Lipman; Peter G. Tuthill; Mark A. Johnson; Donald L. Walters

1998-01-01

388

Phil Taylor Spatial Scientist  

E-print Network

Phil Taylor Spatial Scientist Forest Research ESC Evidence For FC Scotland's Climate Change Risk Assessment Uses Conclusion Methodology Outputs #12;Climate Change Risk Assessments · The CCRA is a requirement under the Climate Change Act to be delivered to parliament in 2012. · UK Government asked

389

Modeling spatial variation in avian survival and residency probabilities.  

PubMed

The importance of understanding spatial variation in processes driving animal population dynamics is widely recognized. Yet little attention has been paid to spatial modeling of vital rates. Here we describe a hierarchical spatial autoregressive model to provide spatially explicit year-specific estimates of apparent survival (phi) and residency (pi) probabilities from capture-recapture data. We apply the model to data collected on a declining bird species, Wood Thrush (Hylocichla mustelina), as part of a broad-scale bird-banding network, the Monitoring Avian Productivity and Survivorship (MAPS) program. The Wood Thrush analysis showed variability in both phi and pi among years and across space. Spatial heterogeneity in residency probability was particularly striking, suggesting the importance of understanding the role of transients in local populations. We found broad-scale spatial patterning in Wood Thrush phi and pi that lend insight into population trends and can direct conservation and research. The spatial model developed here represents a significant advance over approaches to investigating spatial pattern in vital rates that aggregate data at coarse spatial scales and do not explicitly incorporate spatial information in the model. Further development and application of hierarchical capture-recapture models offers the opportunity to more fully investigate spatiotemporal variation in the processes that drive population changes. PMID:20715606

Saracco, James F; Royle, J Andrew; DeSante, David F; Gardner, Beth

2010-07-01

390

Spatial Modeling of Cell Signaling Networks  

PubMed Central

The shape of a cell, the sizes of subcellular compartments and the spatial distribution of molecules within the cytoplasm can all control how molecules interact to produce a cellular behavior. This chapter describes how these spatial features can be included in mechanistic mathematical models of cell signaling. The Virtual Cell computational modeling and simulation software is used to illustrate the considerations required to build a spatial model. An explanation of how to appropriately choose between physical formulations that implicitly or explicitly account for cell geometry and between deterministic vs, stochastic formulations for molecular dynamics is provided, along with a discussion of their respective strengths and weaknesses. As a first step toward constructing a spatial model, the geometry needs to be specified and associated with the molecules, reactions and membrane flux processes of the network. Initial conditions, diffusion coefficients, velocities and boundary conditions complete the specifications required to define the mathematics of the model. The numerical methods used to solve reaction-diffusion problems both deterministically and stochastically are then described and some guidance is provided in how to set up and run simulations. A study of cAMP signaling in neurons ends the chapter, providing an example of the insights that can be gained in interpreting experimental results through the application of spatial modeling. PMID:22482950

Cowan, Ann E.; Moraru, Ion I.; Schaff, James C.; Slepchenko, Boris M.; Loew, Leslie M.

2012-01-01

391

Detection Tracking and Recognition of Human Poses for a Real Time Spatial Game  

E-print Network

, Spatial Game, Real Time. 1 INTRODUCTION Nowadays video-based applications have become more and more. The position and pose information is connected to a spatial game system, and used as the control commandDetection Tracking and Recognition of Human Poses for a Real Time Spatial Game Feifei Huo, Emile A

Veltkamp, Remco

392

On the Qualitative Representation of Spatial Knowledge in 2D Space  

Microsoft Academic Search

Various relation-based systems, concerned with the qualitative representation and processing of spatial knowledge, have been developed in numerous application domains. In this paper we identify the common concepts underlying qualitative spatial knowledge representation, we c ompare the representational properties of the different systems and we outline the computational t asks involved in relation-based spatial i nformation processing. The paper also

Dimitris Papadias; Timos Sellis

1994-01-01

393

Indoor air: Spatial variations of chlorinated pesticides  

NASA Astrophysics Data System (ADS)

The concentrations of two classes of chlorinated pesticides were measured in various locations within four homes. The prevalent compounds were chlorinated derivatives of cyclopentadiene which had been used as termiticides. These compounds were found in basement areas at higher concentrations than in upstairs areas of the homes. Another class of chlorinated pesticide was represented by chlorpyrifos; its spatial profile was consistent with its application in upstairs areas.

Anderson, David J.; Hites, Ronald A.

394

Spatial and spectral light shaping with metamaterials.  

PubMed

Plasmonic metamaterials exhibit strong and tunable dispersion, as a result of their pronounced resonances. This dispersion is used to construct an ultrathin light-shaping element that produces different waves at two distinct wavelengths in the near IR range. The optical response of the pixelated element is adjusted by variations in the geometry of the metamaterial's unit cell. Applications requiring spatial and spectral control of light become feasible. PMID:23065927

Walther, Benny; Helgert, Christian; Rockstuhl, Carsten; Setzpfandt, Frank; Eilenberger, Falk; Kley, Ernst-Bernhard; Lederer, Falk; Tünnermann, Andreas; Pertsch, Thomas

2012-12-11

395

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

1997-01-01

396

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

397

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

398

Modality fusion for graphic design applications  

Microsoft Academic Search

Users must enter a complex mix of spatial and abstract information when operating a graphic design application. Speech \\/ language provides a fluid and natural method for specifying abstract information while a spatial input device is often most intuitive for the entry of spatial information. Thus, the combined speech \\/ gesture interface is ideally suited to this application domain. While

André D. Milota

2004-01-01

399

MobiSpatial : open source for mobile spatial interaction  

Microsoft Academic Search

This paper describes our Mobile Spatial Interaction (MSI) prototype MobiSpatial, which benefits from location and orientation aware smartphones and existing open source spatial data initiatives to facilitate user interaction with the geospatial query process. We utilize today's ubiquitous mobile device as the central computing platform to calculate a mobile user's visibility shape at his\\/her current location. MobiSpatial uses this shape

Junjun Yin; James D. Carswell

2012-01-01

400

Optimizing Online Spatial Data Analysis with Sequential Query Patterns  

E-print Network

of Computing and Information Sciences, Florida International University {czeng001, hli019, hwang033, yguan004 understand the spatial data due to the inherently complex and dynamic nature of GIS applications. To address the sequential query patterns from the user query logs of GIS applications. The sequential query patterns

Chen, Shu-Ching

401

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

402

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

403

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

404

Collimator spatial resolution  

Microsoft Academic Search

Pixellated detectors based on cadmium-zinc telluride (CZT) are a promising alternative to NaI-based SPECT cameras. The performance of either system is quantitatively described in terms of resolution and sensitivity. This investigation is based on an analytical model published earlier, describing SPECT collimators according to the NEMA definitions of planar sensitivity and system spatial resolution without scatter. We have extended the

H. Wieczorek; A. Goedicke; F. Edstrom; C. Degenhardt; H. Botterweck; R. Bippus

2005-01-01

405

Application of multi-stable isotope (?13C, ?15N, ?34S, ?37Cl) assays to assess spatial separation of fish (longnose sucker Catostomus catostomus) in an area receiving complex effluents  

Microsoft Academic Search

Incorporation of stable isotope analysis (SIA) into routine environmental effects monitoring programs of receiving waters may enable determination of the spatial extent of biotic exposure and discrimination among sources of complex effluents. To evaluate this hypothesis, longnose sucker (Catostomus catostomus) were collected from four sites along the Athabasca River, Alberta (upstream reference site, two sites downstream of effluents from two

M. G. Dube; Glenn A. Benoy; Sandra Blenkinsopp; Jenny-Marie Ferone; Robert B. Brua; Leonard I. Wassenaar

2005-01-01

406

4, 627654, 2007 A spatially  

E-print Network

HESSD 4, 627­654, 2007 A spatially distributed analysis of river sediment yield S. Grauso et al System Sciences A spatially distributed analysis of erosion susceptibility and sediment yield in a river. Grauso (grauso@casaccia.enea.it) 627 #12;HESSD 4, 627­654, 2007 A spatially distributed analysis of river

Boyer, Edmond

407

Spatial Statistics for Environmental Epidemiology  

E-print Network

of methods and techniques of spatial data analysis used in environmental epidemiology. Speci c topics includeSpatial Statistics for Environmental Epidemiology Peter Diggle (Medical Statistics Unit, Lancaster intensities 2.2 Poisson processes 2.3 Cox processes/cluster processes 3. Case-control methods 3.1 Spatial

Diggle, Peter J.

408

Real-time generalization of XML-encoded spatial data for the Web and mobile devices  

Microsoft Academic Search

The increased use of the Web and the Mobile Internet as a platform for geospatial applications necessitates development of improved interoperability between computing systems and underscores the need to apply standardized network technologies in processes dealing with spatial data. The generalization approach applicable in network?based spatial data services may be based on different technologies, compared with traditional cartographic generalization. Here,

Lassi Lehto; L. Tiina Sarjakoski

2005-01-01

409

MONITORING METHOD OF COW ANTHRAX BASED ON GIS AND SPATIAL STATISTICAL  

E-print Network

information system (GIS) is a computer application system, which possesses the ability of manipulating spatial for randomness. The GIS computer application software ArcGIS9.1 was used to overcome the lack of data of samplingMONITORING METHOD OF COW ANTHRAX BASED ON GIS AND SPATIAL STATISTICAL ANALYSIS Lin Li 1 , Yong Yang

Boyer, Edmond

410

Design and Optimization of Spatial Organizations For Context Exchange and Surveillance  

E-print Network

quantities of con- textual information that is mainly relevant/useful when a user/mobile is situated associated with each cell. The model uses random tessellations to generate spatial partitions of the space of applications' spatial content scaling. I. Introduction Context-awareness refers to the ability of applications

de Veciana, Gustavo

411

Chemistry with spatial control using particles and streams†  

PubMed Central

Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis. PMID:23145348

Kalinin, Yevgeniy V.; Murali, Adithya

2012-01-01

412

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

413

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

414

Beyond position - spatial context for mobile information retrieval systems  

Microsoft Academic Search

Within context-aware mobile applications, location information usually plays a major role for information selection and adaptivity. In this paper, we explore the geospatial dimension between simple position-aware and fully context-aware information systems by examining in-depth the features of spatial context beyond mere position. We describe how these features can be used to create spatial queries in a mobile information retrieval

Dirk Ahlers; Susanne Boll

2009-01-01

415

EgoViz - A Mobile Based Spatial Interaction System  

Microsoft Academic Search

This paper describes research carried out in the area of mobile spatial interaction and the development of a mobile (i.e. on-device) version of a simulated web-based 2D directional query processor. The TellMe application integrates location (from GPS, GSM, WiFi) and orientation (from digital compass\\/tilt sensors) sensing technologies into an enhanced spatial query processing module capable of exploiting a mobile device's

Keith Gardiner; Junjun Yin; James D. Carswell

2009-01-01

416

Two-stage spatial filtering for diffraction pattern analysis.  

PubMed

The use of optical power spectrum analysis for feature detection and classification is often restricted by the superposition of the aperture spectrum. A spatial frequency filtering technique using a circular aperture and filters has been previously proposed to separate the object and aperture spectra. An adaptation of this technique using square apertures and an opaque cross spatial filter offers improved performance for some applications. Numerical calculations and experimental results are given comparing the two techniques. PMID:20309258

Blodgett, J A; Easton, R L

1981-03-15

417

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

418

On the Fast Construction of Spatial Hierarchies for Ray Tracing  

Microsoft Academic Search

In this paper we address the problem of fast construction of spatial hierarchies for ray tracing with applications in animated environments including non-rigid animations. We discuss the properties of currently used techniques with O(N log N) construction time for kd-trees and bounding volume hierarchies. Further, we propose a hybrid data structure blending a spatial kd-tree with bounding volume primitives. We

Vlastimil Havran; Robert Herzog; Hans-Peter Seidel

2006-01-01

419

Spatial Database Modeling for Indoor Navigation Systems  

NASA Astrophysics Data System (ADS)

For many years, cartographers are involved in designing GIS and navigation systems. Most GIS applications use the outdoor data. Increasingly, similar applications are used inside buildings. Therefore it is important to find the proper model of indoor spatial database. The development of indoor navigation systems should utilize advanced teleinformation, geoinformatics, geodetic and cartographical knowledge. The authors present the fundamental requirements for the indoor data model for navigation purposes. Presenting some of the solutions adopted in the world they emphasize that navigation applications require specific data to present the navigation routes in the right way. There is presented original solution for indoor data model created by authors on the basis of BISDM model. Its purpose is to expand the opportunities for use in indoor navigation.

Gotlib, Dariusz; Gnat, Mi?osz

2013-12-01

420

Spatial uncertainty analysis: Propagation of interpolation errors in spatially distributed models  

USGS Publications Warehouse

In simulation modelling, it is desirable to quantify model uncertainties and provide not only point estimates for output variables but confidence intervals as well. Spatially distributed physical and ecological process models are becoming widely used, with runs being made over a grid of points that represent the landscape. This requires input values at each grid point, which often have to be interpolated from irregularly scattered measurement sites, e.g., weather stations. Interpolation introduces spatially varying errors which propagate through the model We extended established uncertainty analysis methods to a spatial domain for quantifying spatial patterns of input variable interpolation errors and how they propagate through a model to affect the uncertainty of the model output. We applied this to a model of potential evapotranspiration (PET) as a demonstration. We modelled PET for three time periods in 1990 as a function of temperature, humidity, and wind on a 10-km grid across the U.S. portion of the Columbia River Basin. Temperature, humidity, and wind speed were interpolated using kriging from 700- 1000 supporting data points. Kriging standard deviations (SD) were used to quantify the spatially varying interpolation uncertainties. For each of 5693 grid points, 100 Monte Carlo simulations were done, using the kriged values of temperature, humidity, and wind, plus random error terms determined by the kriging SDs and the correlations of interpolation errors among the three variables. For the spring season example, kriging SDs averaged 2.6??C for temperature, 8.7% for relative humidity, and 0.38 m s-1 for wind. The resultant PET estimates had coefficients of variation (CVs) ranging from 14% to 27% for the 10-km grid cells. Maps of PET means and CVs showed the spatial patterns of PET with a measure of its uncertainty due to interpolation of the input variables. This methodology should be applicable to a variety of spatially distributed models using interpolated inputs.

Phillips, D.L.; Marks, D.G.

1996-01-01

421

Visualized Spatial Data Classifying Based on Spatial Data Mining  

Microsoft Academic Search

A spatial data mining prototype system called Visual Geo-Classify System (VGCS) use to classify spatial data based on VC++6.0 is designed and developed. The authors used examples of data verified the effectiveness on system performance, algorithms and rules. The results indicate that this prototype system is a practical and extensible Visual Interactive Spatial Data Mining tool, it can achieve the

Zelu Jia; Yaolin Liu

2009-01-01

422

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

423

Enhanced spatial models for predicting the geographic distributions of tick-borne pathogens  

PubMed Central

Background Disease maps are used increasingly in the health sciences, with applications ranging from the diagnosis of individual cases to regional and global assessments of public health. However, data on the distributions of emerging infectious diseases are often available from only a limited number of samples. We compared several spatial modelling approaches for predicting the geographic distributions of two tick-borne pathogens: Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, and Anaplasma phagocytophilum, the causative agent of human granulocytotropic anaplasmosis. These approaches extended environmental modelling based on logistic regression by incorporating both spatial autocorrelation (the tendency for pathogen distributions to be clustered in space) and spatial heterogeneity (the potential for environmental relationships to vary spatially). Results Incorporating either spatial autocorrelation or spatial heterogeneity resulted in substantial improvements over the standard logistic regression model. For E. chaffeensis, which was common within the boundaries of its geographic range and had a highly clustered distribution, the model based only on spatial autocorrelation was most accurate. For A. phagocytophilum, which has a more complex zoonotic cycle and a comparatively weak spatial pattern, the model that incorporated both spatial autocorrelation and spatially heterogeneous relationships with environmental variables was most accurate. Conclusion Spatial autocorrelation can improve the accuracy of predictive disease risk models by incorporating spatial patterns as a proxy for unmeasured environmental variables and spatial processes. Spatial heterogeneity can also improve prediction accuracy by accounting for unique ecological conditions in different regions that affect the relative importance of environmental drivers on disease risk. PMID:18412972

Wimberly, Michael C; Baer, Adam D; Yabsley, Michael J

2008-01-01

424

Spatially heterogeneous strength in thrust fault zones  

NASA Astrophysics Data System (ADS)

Deformation in the hanging wall of the Lewis thrust fault at Marias Pass, northwest Montana, is heterogeneous in space, with regions dominated by either large-scale contraction or extension faults. The distribution of mesoscopic structures within the two regions also differs. The density of fractures is highest in the extensional region, whereas the density of solution seams is highest in the contractional regime. This spatial heterogeneity of structures at the base of the Lewis thrust sheet may result from spatially heterogeneous fault zone strength. In analytical models of an elastic thrust sheet overlying a fault represented by spatial heterogeneity in shear traction or displacement, stress magnitudes and principal directions vary with position within the model thrust sheet. With the application of a Mohr-Coulomb criterion, contraction and extension faults initiate within localized regions at the base of the model thrust sheet. Spatial variations in mean stress at the base of the thrust sheet predicted by the models may explain both the greater density of solution seams in the contractional region than in the extensional region and the greater density of mesoscopic faults and veins in the extensional region than in the contractional region of the Marias Pass exposure. The spatial heterogeneity of pressure solution and cataclasis in response to variable mean stress within a fault zone of heterogeneous strength may facilitate thrust sheet movement relative to movement over a fault zone of uniform strength, because a decrease in mean stress enhances cataclasis and an increase in mean stress maintains a constant shear stress during pressure solution.

Erickson, S. Gregg; Wiltschko, David V.

1991-05-01

425

Spatially heterogeneous strength in thrust faults zones  

NASA Astrophysics Data System (ADS)

Deformation in the hanging wall of the Lewis thrust at Marias Pass, northwest Montana, is heterogeneous in space, with regions dominanted by either large-scale contraction or extension faults. The distribution of mesoscopic structures within the two regions also differs. The density of fracture is highest in the extensional region, whereas the density of solution seams is highest in the contractional regime. This spatial heterogeneity of strutures at the base the Lewis thrust sheet may result from spatially heterogeneous fault zone strength. In analytical models of an elastic thrust sheet overlying a fault represented by spatial heterogeneity in shear traction or displacement, stress magnitude and principal directions vary with position within the model thrust sheet. With the application of a Mohr-Coulomb criterion, contraction and extension faults initiate within localized regions at the base of the model thrust sheet. Spatial variations in mean stress at the base of the thrust sheet predicted by the models may explain both the greater density of solution seams in the contractional region than in the extensional region and the greater density of mesoscopic faults and veins in the extensional region than in the contractional region of the mesoscopic faults and veins in the extensional region than int he contractional region of the Marias Pass exposure. The spatial heterogeneity of pressure solution and cataclasis in response to variable mean stress within a fault zone of heterogeneous strength may facilitate thrust sheet movement relative to movement over a fault zone of uniform strength, because a decrease in mean stress enhances cataclasis and an increase in mean stress maintains a constant shear stress during pressure solution.

Gregg Erickson, S.; Wiltschko, David V.

1991-05-01

426

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

427

Fractals and Spatial Methods for Mining Remote Sensing Imagery  

NASA Technical Reports Server (NTRS)

The rapid increase in digital remote sensing and GIS data raises a critical problem -- how can such an enormous amount of data be handled and analyzed so that useful information can be derived quickly? Efficient handling and analysis of large spatial data sets is central to environmental research, particularly in global change studies that employ time series. Advances in large-scale environmental monitoring and modeling require not only high-quality data, but also reliable tools to analyze the various types of data. A major difficulty facing geographers and environmental scientists in environmental assessment and monitoring is that spatial analytical tools are not easily accessible. Although many spatial techniques have been described recently in the literature, they are typically presented in an analytical form and are difficult to transform to a numerical algorithm. Moreover, these spatial techniques are not necessarily designed for remote sensing and GIS applications, and research must be conducted to examine their applicability and effectiveness in different types of environmental applications. This poses a chicken-and-egg problem: on one hand we need more research to examine the usability of the newer techniques and tools, yet on the other hand, this type of research is difficult to conduct if the tools to be explored are not accessible. Another problem that is fundamental to environmental research are issues related to spatial scale. The scale issue is especially acute in the context of global change studies because of the need to integrate remote-sensing and other spatial data that are collected at different scales and resolutions. Extrapolation of results across broad spatial scales remains the most difficult problem in global environmental research. There is a need for basic characterization of the effects of scale on image data, and the techniques used to measure these effects must be developed and implemented to allow for a multiple scale assessment of the data before any useful process-oriented modeling involving scale-dependent data can be conducted. Through the support of research grants from NASA, we have developed a software module called ICAMS (Image Characterization And Modeling System) to address the need to develop innovative spatial techniques and make them available to the broader scientific communities. ICAMS provides new spatial techniques, such as fractal analysis, geostatistical functions, and multiscale analysis that are not easily available in commercial GIS/image processing software. By bundling newer spatial methods in a user-friendly software module, researchers can begin to test and experiment with the new spatial analysis methods and they can gauge scale effects using a variety of remote sensing imagery. In the following, we describe briefly the development of ICAMS and present application examples.

Lam, Nina; Emerson, Charles; Quattrochi, Dale

2003-01-01

428

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

429

On losses and spatial mode characteristics of a wide-aperture Fabry - Perot resonator upon a periodic spatial perturbation of the field phase at one of the mirrors  

SciTech Connect

The losses and spatial mode characteristics of a wide-aperture Fabry - Perot resonator are studied upon a periodic spatial perturbation of the radiation-field phase in a thin layer adjacent to one of the resonator mirrors. It is shown that two regions with different perturbation scales, which affect the losses and distortions of the spatial characteristics of the first modes, are formed for a given perturbation amplitude in the general case. (laser applications and other topics in quantum electronics)

Elkin, N N [State Research Center of Russian Federation 'Troitsk Institute for Innovation and Fusion Research', Troitsk, Moscow Region (Russian Federation); Ledenev, V I [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

2002-07-31

430

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

431

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

432

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

433

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

434

Synergy Between Ground Measurements and High Spatial Resolution Imagery to Validate Medium Spatial Resolution Land Surface Product  

NASA Astrophysics Data System (ADS)

Currently, several biophysical variables such as the Leaf Area Index (LAI), the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) and the surface albedo are derived from remote sensing observations acquired with medium spatial resolution sensors (250m to 7km). Because of their high temporal frequency and their important spatial coverage, these products are very useful to describe the mass and energy fluxes between the earth surface and the atmosphere. Since these variables are required for an important range of investigations and applications, it is important to assess their accuracy. Validation activity consists in evaluating by independent means the quality of the land surface products estimated from coarse resolution sensors. Validation methods consist in generating a ground truth map of these products at high spatial resolution. These maps are produced by using ground measurements of the biophysical variable and radiometric data from a high spatial resolution sensor (10m-30m). The relationship between a biophysical variable and radiometric imagery, called the transfer function, allows extending the local ground measurements to the entire high spatial resolution image. The resulting biophysical variable map is aggregated to be compared with the medium spatial resolution satellite biophysical products. Several geometrical issues influence the validation results: - the registration accuracy of the local ground measurements relative to the high spatial resolution image - the difference of spatial support between the ground measurement support and the high spatial resolution pixel - the registration accuracy between the high and medium resolution images - the point spread function (PSF) associated to the medium spatial resolution image This work proposes a methodology to account for these sources of uncertainties within the validation process. First, these problems are investigated at the field measurement scale. The registration accuracy between ground measurement located by GPS and high spatial resolution pixel is modeled by a Gaussian random variable. For each possible relative position, the ground measurement is related to the radiometric data for the surrounding area weighted by the ground measurement spatial support area. A Monte Carlo simulation scheme accounting for the positional accuracy provides the probability distribution function of the parameters defining the transfer function. Second, registration error is investigated when aggregated high spatial resolution image is compared with coarse resolution image. The registration error is minimized by getting the best geometrical match between the two images using correlation techniques. Finally, the importance of the PSF associated to the medium spatial resolution biophysical products is evaluated using data from MODIS and VEGETATION sensors. This investigation is applied to several validation sites expressing a range of spatial heterogeneity.

Garrigues, S.; Morisette, J.; Baret, F.; Privette, J.

2005-12-01

435

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

436

Spatial Organization of Young Children.  

ERIC Educational Resources Information Center

This study was designed to consider effects of age, sex, intelligence, lateral usage, and lateral awareness on young children's performance of spatial organization tasks. The sample consisted of 79 Caucasian, middle socioeconomic status nursery school children (mean C.A. 57.80, S.D. 4.47 months), 44 boys and 35 girls. Spatial organization was…

Keogh, Barbara K.

437

MALARIA MODELS WITH SPATIAL EFFECTS  

E-print Network

CHAPTER 1 MALARIA MODELS WITH SPATIAL EFFECTS Daozhou Gao1 and Shigui Ruan2 1 Francis I. Proctor provide