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Optimization of mobile radioactivity monitoring networks / Gerard B.M. Heuvelink in International journal of geographical information science IJGIS, vol 24 n°3-4 (march 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°3-4 (march 2010) . - pp 365 - 382 Titre : Optimization of mobile radioactivity monitoring networks Type de document : Article/Communication Auteurs : Gerard B.M. Heuvelink, Auteur ; Zhiheng Jiang , Auteur ; S. De Bruin, Auteur ; C. Twenhöfel, Auteur Année de publication : 2010 Article en page(s) : pp 365 - 382 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] accident nucléaire [Termes IGN] algorithme du recuit simulé [Termes IGN] allocation [Termes IGN] appareil portable [Termes IGN] contamination [Termes IGN] distribution spatiale [Termes IGN] géostatistique [Termes IGN] lever mobile [Termes IGN] Pays-Bas [Termes IGN] risque technologique Résumé : (Auteur) In case of a nuclear accident, decision makers rely on high-resolution and accurate information about the spatial distribution of radioactive contamination surrounding the accident site. However, the static nuclear monitoring networks of many European countries are generally too coarse to provide the desired level of spatial accuracy. In the Netherlands, authorities are considering a strategy in which measurement density is increased during an emergency using complementary mobile measuring devices. This raises the question, where should these mobile devices be placed? This article proposes a geostatistical methodology to optimize the allocation of mobile measurement devices, such that the expected weighted sum of false-positive and false-negative areas (i.e. false classification into safe and unsafe zones) is minimized. Radioactivity concentration is modelled as the sum of a deterministic trend and a zero-mean spatially correlated stochastic residual. The trend is defined as the outcome of a physical atmospheric dispersion model, NPK-PUFF. The residual is characterized by a semivariogram of differences between the outputs of various NPK-PUFF model runs, designed to reflect the effect of uncertainty in NPK-PUFF meteorological inputs (e.g. wind speed, wind direction). Spatial simulated annealing is used to obtain the optimal monitoring design, in which accessibility of sampling sites (e.g. distance to roads) is also considered. Although the methodology is computationally demanding, results are promising and the computational load may be considerably reduced to compute optimal mobile monitoring designs in nearly real time. Copyright Taylor & Francis Numéro de notice : A2010-142 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802646687 En ligne : http://dx.doi.org/10.1080/13658810802646687 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30337 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010022	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Detecting negative spatial autocorrelation in georeferenced random variables / Daniel A. Griffith in International journal of geographical information science IJGIS, vol 24 n°3-4 (march 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°3-4 (march 2010) . - pp 417 - 437 Titre : Detecting negative spatial autocorrelation in georeferenced random variables Type de document : Article/Communication Auteurs : Daniel A. Griffith, Auteur ; Guiseppe Arbia, Auteur Année de publication : 2010 Article en page(s) : pp 417 - 437 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] agrégation spatiale [Termes IGN] autocorrélation spatiale [Termes IGN] distribution spatiale [Termes IGN] inférence statistique [Termes IGN] régression [Termes IGN] variable aléatoire [Termes IGN] variable régionalisée [Termes IGN] vecteur propre Résumé : (Auteur) Negative spatial autocorrelation refers to a geographic distribution of values, or a map pattern, in which the neighbors of locations with large values have small values, the neighbors of locations with intermediate values have intermediate values, and the neighbors of locations with small values have large values. Little is known about negative spatial autocorrelation and its consequences in statistical inference in general, and regression-based inference in particular, with spatial researchers to date concentrating mostly on understanding the much more frequently encountered case of positive spatial autocorrelation. What are the spatial contexts within which negative spatial autocorrelation should be readily found? What are its inferential consequences for regression models? This paper presents selected empirical examples of negative spatial autocorrelation, adding to the slowly growing literature about this phenomenon. Copyright Taylor & Francis Numéro de notice : A2010-143 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810902832591 En ligne : http://dx.doi.org/10.1080/13658810902832591 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30338 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010022	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Spatial data infrastructures as complex adaptative systems / Lucasz Grus in International journal of geographical information science IJGIS, vol 24 n°3-4 (march 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°3-4 (march 2010) . - pp 439 - 463 Titre : Spatial data infrastructures as complex adaptative systems Type de document : Article/Communication Auteurs : Lucasz Grus, Auteur ; Joep Crompvoets, Auteur ; Arnold K. Bregt, Auteur Année de publication : 2010 Article en page(s) : pp 439 - 463 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Infrastructure de données [Termes IGN] estimation statistique [Termes IGN] infrastructure nationale des données localisées [Termes IGN] intégration de données [Termes IGN] qualité des données [Termes IGN] système complexe Résumé : (Auteur) Many researchers throughout the world have been struggling to better understand and describe spatial data infrastructures (SDIs). Our knowledge of the real forces and mechanisms behind SDIs is still very limited. The reason for this difficulty might lie in the complex, dynamic and multifaceted nature of SDIs. To evaluate the functioning and effects of SDIs we must have a proper theory and understanding of their nature. This article describes a new approach to understanding SDIs by looking at them through the lens of complex adaptive systems (CASs). CASs are frequently described by the following features and behaviours: complexity, components, self-organization, openness, unpredictability, nonlinearity and adaptability, scale-independence, existence of feedback loop mechanism and sensitivity to initial conditions. In this article both CAS and SDI features are presented, examined and compared using three National SDI case studies from the Netherlands, Australia and Poland. These three National SDIs were carefully analysed to identify CAS features and behaviours. In addition, an Internet survey of SDI experts was carried out to gauge the degree to which they consider SDIs and CASs to be similar. This explorative study provides evidence that to a certain extent SDIs can be viewed as CASs because they have many features in common and behave in a similar way. Studying SDIs as CASs has significant implications for our understanding of SDIs. It will help us to identify and better understand the key factors and conditions for SDI functioning. Assuming that SDIs behave much like CASs, this also has implications for their assessment: assessment techniques typical for linear and predictable systems may not be valid for complex and adaptive systems. This implies that future studies on the development of an SDI assessment framework must consider the complex and adaptive nature of SDIs. Copyright Taylor & Francis Numéro de notice : A2010-144 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802687319 En ligne : http://dx.doi.org/10.1080/13658810802687319 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30339 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010022	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Development of an interoperable tool to facilitate spatial data integration in the contexte of SDI / H. Mohammadi in International journal of geographical information science IJGIS, vol 24 n°3-4 (march 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°3-4 (march 2010) . - pp 487 - 505 Titre : Development of an interoperable tool to facilitate spatial data integration in the contexte of SDI Type de document : Article/Communication Auteurs : H. Mohammadi, Auteur ; Abbas Rajabifard, Auteur ; I.P. Williamson, Auteur Année de publication : 2010 Article en page(s) : pp 487 - 505 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Infrastructure de données [Termes IGN] cohérence des données [Termes IGN] données multisources [Termes IGN] infrastructure nationale des données localisées [Termes IGN] intégration de données [Termes IGN] interopérabilité Résumé : (Auteur) The integration of multisource heterogeneous spatial data is one of the major challenges for many spatial data users. To facilitate multisource spatial data integration, many initiatives including federated databases, feature manipulation engines (FMEs), ontology-driven data integration and spatial mediators have been proposed. The major aim of these initiatives is to harmonize data sets and establish interoperability between different data sources. On the contrary, spatial data integration and interoperability is not a pure technical exercise, and there are other nontechnical issues including institutional, policy, legal and social issues involved. Spatial Data Infrastructure (SDI) framework aims to better address the technical and nontechnical issues and facilitate data integration. The SDIs aim to provide a holistic platform for users to interact with spatial data through technical and nontechnical tools. This article aims to discuss the complexity of the challenges associated with data integration and propose a tool that facilitates data harmonization through the assessment of multisource spatial data sets against many measures. The measures represent harmonization criteria and are defined based on the requirement of the respective jurisdiction. Information on technical and nontechnical characteristics of spatial data sets is extracted to form metadata and actual data. Then the tool evaluates the characteristics against measures and identifies the items of inconsistency. The tool also proposes available manipulation tools or guidelines to overcome inconsistencies among data sets. The tool can assist practitioners and organizations to avoid the time-consuming and costly process of validating data sets for effective data integration. Copyright Taylor & Francis Numéro de notice : A2010-145 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810902881903 En ligne : http://dx.doi.org/10.1080/13658810902881903 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30340 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010022	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A cell-based algorithm for evaluating directional distances in GIS / S. Yang in International journal of geographical information science IJGIS, vol 24 n°3-4 (march 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°3-4 (march 2010) . - pp 577 - 590 Titre : A cell-based algorithm for evaluating directional distances in GIS Type de document : Article/Communication Auteurs : S. Yang, Auteur ; J. Yong, Auteur ; J. Sun, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 577 - 590 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] distance [Termes IGN] système d'information géographique Résumé : (Auteur) Directional distance is commonly used in geographical information systems as a measure of openness. In previous works, the sweep line method and the interval tree method have been employed to evaluate the directional distances on vector maps. Both methods require rotating original maps and study points in every direction of interest. In this article, we propose a cell-based algorithm that pre-processes a map only once; that is, it subdivides the map into a group of uniform-sized cells and records each borderline of the map into the cells traversed by its corresponding line segment. Based on the pre-processing result, the neighbouring borderlines of a study point can be directly obtained through the neighbouring cells of the point, and the borderlines in a definite direction can be simply acquired through the cells traversed by the half line as well. As a result, the processing step does not need to enumerate all the borderlines of the map when determining whether a point is on a borderline or finding the nearest intersection between a half line and the borderlines. Furthermore, we implement the algorithm for determining fetch length in coastal environment. Once the pre-processing is done, the algorithm can work in a complex archipelago environment such as to calculate the fetch lengths in multiple directions, to determine the inclusion property of a point, and to deal with the singularity of a study point on a borderline. Copyright Taylor & Francis Numéro de notice : A2010-146 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810902988419 En ligne : http://dx.doi.org/10.1080/13658810902988419 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30341 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010022	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible