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The geometry of space-time prisms with uncertain anchors / Bart Kuijpers in International journal of geographical information science IJGIS, vol 31 n° 9-10 (September - October 2017)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 31 n° 9-10 (September - October 2017) . - pp 1722 - 1748 Titre : The geometry of space-time prisms with uncertain anchors Type de document : Article/Communication Auteurs : Bart Kuijpers, Auteur ; Walied Othman, Auteur Année de publication : 2017 Article en page(s) : pp 1722 - 1748 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatio-temporelle [Termes IGN] données spatiotemporelles [Termes IGN] erreur de mesure [Termes IGN] géométrie [Termes IGN] incertitude géométrique [Termes IGN] modèle conceptuel de données spatio-temporelles [Termes IGN] objet mobile [Termes IGN] prisme spatio-temporel [Termes IGN] Time-geography [Termes IGN] zone d'intérêt Résumé : (Auteur) Space-time prisms envelop all spatio-temporal locations that moving objects may have visited between two of their known spatio-temporal locations, given a bound on their travel speed. In this context, the known locations are often the result of observations or measurements, and they are called ‘anchor points’. The classic space-time prism, in isotropic two-dimensional space, as well as in transportation networks, assumes that the measurements of these anchor points are exact. Whereas, in many applications, we can assume that time can be measured fairly precisely, this assumption is unrealistic for the spatial components of measured locations (we think of Global Positioning System (GPS) errors, for instance). In this paper, we extend the classical prism from anchor points to circular ‘anchor regions’ that capture the uncertainty or error on their measurement. We define the notion of a space-time prism with uncertain anchor points, called uncertain prism, for short. We study the geometry of uncertain prisms in an arbitrary metric space to make this concept as widely applicable as possible. We also focus on the rims of uncertain space-time prisms, which demarcate the area that a moving object can have visited between two anchor regions (given some local speed limitations). Numéro de notice : A2017-504 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2017.1319950 En ligne : https://doi.org/10.1080/13658816.2017.1319950 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86449 [article]

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Anchor uncertainty and space-time prisms on road networks / Bart Kuijpers in International journal of geographical information science IJGIS, vol 24 n°7-8 (july 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°7-8 (july 2010) . - pp 1223 - 1248 Titre : Anchor uncertainty and space-time prisms on road networks Type de document : Article/Communication Auteurs : Bart Kuijpers, Auteur ; Harvey J. Miller, Auteur ; T. Neutens, Auteur ; Walied Othman, Auteur Année de publication : 2010 Article en page(s) : pp 1223 - 1248 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] incertitude géométrique [Termes IGN] logiciel de calcul scientifique [Termes IGN] objet mobile [Termes IGN] réseau routier Résumé : (Auteur) Space-time prisms capture all possible locations of a moving person or object between two known locations and times given the maximum travel velocities in the environment. These known locations or 'anchor points' can represent observed locations or mandatory locations because of scheduling constraints. The classic space-time prism as well as more recent analytical and computational versions in planar space and networks assume that these anchor points are perfectly known or fixed. In reality, observations of anchor points can have error, or the scheduling constraints may have some degree of pliability. This article generalizes the concept of anchor points to anchor regions: these are bounded, possibly disconnected, subsets of space-time containing all possible locations for the anchor points, with each location labelled with an anchor probability. We develop two algorithms for calculating network-based space-time prisms based on these probabilistic anchor regions. The first algorithm calculates the envelope of all space-time prisms having an anchor point within a particular anchor region. The second algorithm calculates, for any space-time point, the probability that a space-time prism with given anchor regions contains that particular point. Both algorithms are implemented in Mathematica to visualize travel possibilities in case the anchor points of a space-time prism are uncertain. We also discuss the complexity of the procedures, their use in analysing uncertainty or flexibility in network-based prisms and future research directions. Numéro de notice : A2010-327 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810903321339 En ligne : https://doi.org/10.1080/13658810903321339 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30521 [article]

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079-2010042	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Modeling uncertainty of moving objects on road networks via space- time prims / Bart Kuijpers in International journal of geographical information science IJGIS, vol 23 n°9-10 (september 2009)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 23 n°9-10 (september 2009) . - pp 1095 - 1117 Titre : Modeling uncertainty of moving objects on road networks via space- time prims Type de document : Article/Communication Auteurs : Bart Kuijpers, Auteur ; Walied Othman, Auteur Année de publication : 2009 Article en page(s) : pp 1095 - 1117 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatio-temporelle [Termes IGN] base de données d'objets mobiles [Termes IGN] incertitude de position [Termes IGN] logiciel de calcul scientifique [Termes IGN] Mathematica [Termes IGN] modélisation spatio-temporelle [Termes IGN] objet mobile [Termes IGN] réseau routier [Termes IGN] visualisation 3D Résumé : (Auteur) Moving objects produce trajectories, which are typically observed in a finite sample of time-stamped locations. Between sample points, we are uncertain about the moving objects's location. When we assume extra information about an object, for instance, a (possibly location-dependent) speed limit, we can use space-time prisms to model the uncertainty of an object's location. Until now, space-time prisms have been studied for unconstrained movement in the 2D plane. In this paper, we study space-time prisms for objects that are constrained to travel on a road network. Movement on a road network can be viewed as essentially one-dimensional. We describe the geometry of a space-time prism on a road network and give an algorithm to compute and visualize space-time prisms. For experiments and illustration, we have implemented this algorithm in MATHEMATICA. Furthermore, we study the alibi query, which asks whether two moving objects could have possibly met or not. This comes down to deciding if the chains of space-time prisms produced by these moving objects intersect. We give an efficient algorithm to answer the alibi query for moving objects on a road network. This algorithm also determines where and when two moving objects may have met. Copyright Taylor & Francis Numéro de notice : A2009-381 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802097485 En ligne : https://doi.org/10.1080/13658810802097485 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30011 [article]

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079-09061	RAB	Revue	Centre de documentation	En réserve L003	Disponible