References of "Hallot, Pierre"
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See detailCASTLE4D: An Archaeological Information System Based on 3D Point Clouds
Luczfalvy Jancsó, Andrea ULg; Billen, Roland ULg; Hoffsummer, Patrick ULg et al

in Lerma, José Luis (Ed.) Proceedings of the 8th International Congress on Archaeology, Computer Graphics, Cultural Heritage and Innovation : 'ARQUEOLÓGICA 2.0', Valence 5-7 septembre 2016 (in press)

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See detailEnhancing Spatio-Temporal Identity: States of Existence and Presence
Hallot, Pierre ULg; Billen, Roland ULg

in International Journal of Geo-Information (2016), 5(62),

This work presents a new approach that aims to characterize the spatio-temporal relationships that exist between geographical objects that are absent or non-existent at the moment of analysis. First, we ... [more ▼]

This work presents a new approach that aims to characterize the spatio-temporal relationships that exist between geographical objects that are absent or non-existent at the moment of analysis. First, we would like to propose a formal analysis of the spatio-temporal states of presence and existence of a geographical object. We will then use a combination of these states in order to define a set of life and motion configurations. The model developed then serves as a formal basis for the realization of a series of spatio-temporal queries based on an analysis of patterns in the succession of spatio-temporal states. The entire approach is then demonstrated by using the example of the organization of a scientific conference by defining the spatio-temporal relationships between the conference participants. The research methodology is finally compared with a real dataset taken from a geolocalized social network to show the efficiency of this type of management. [less ▲]

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See detailLe patrimoine en 3D : de l’acquisition aux nuages de points intelligents
Billen, Roland ULg; Poux, Florent ULg; Hallot, Pierre ULg et al

Scientific conference (2016, February 17)

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See detailSaint Paul 3D - Acquisition tridimensionnelle de la cathédrale via LaserScan
Hallot, Pierre ULg

in Journée d'étude organisée par l'Institut du Patrimoine Wallon et le Comité Patrimoine et Histoire de la FABI (2015, November 27)

Les nouvelles techniques LiDAR (Light Detection and Ranging) et photogrammétriques permettent d’acquérir rapidement un volume important de données 3D. Le terme LiDAR désigne tout instrument de mesure ... [more ▼]

Les nouvelles techniques LiDAR (Light Detection and Ranging) et photogrammétriques permettent d’acquérir rapidement un volume important de données 3D. Le terme LiDAR désigne tout instrument de mesure (terrestre, aéroporté) basé sur l’analyse des propriétés d’un faisceau renvoyé vers un émetteur (Poux et al. 2014). Conscient de l’énorme potentiel de ces techniques, l’Unité de Géomatique de l’Université de Liège a réalisé la numérisation de la Cathédrale Saint‐Paul de Liège. Ce projet a été initié via une collaboration avec le Matthieu Piavaux (FUNDP) et financée par le FNRS. Au‐delà des aspects de conservation et d’analyse du bâti, cette numérisation nous a permis de mettre en lumière les principes et limitations de la technique même d’acquisition de données 3D via LiDAR ainsi que ses limitations tant matérielles (sur terrain) que logicielles (traitement des données). Le jeu de donnée obtenu de la numérisation sert également de base fondamentale à un ensemble de projets de recherches (notamment via la réalisation de thèses de doctorats) visant à la segmentation automatique de nuages de points, de reconstruction d’objets tridimensionnelles, d’analyse de qualité d’ajustements. Par la suite, nous détaillons la méthodologie utilisée pour l’acquisition du nuage de points 3D ainsi que les différents principes de calage de nuages. Le chapitre suivant sera consacré à la présentation de résultats ainsi que de premiers développements en termes de segmentation automatique. Finalement, nous dresserons quelques perspectives de représentations. [less ▲]

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See detailWho are my Visitors and Where do They Come From? An Analysis Based on Foursquare Check-ins and Place-based Semantics.
Hallot, Pierre ULg; Stewart, Kathleen; Billen, Roland ULg

in Eurographics Workshop on Urban Data Modelling and Visualisation 2015 (2015, November 23)

Activity recommendation systems aims at providing relevant information depending on targeted users' groups. For instance in a city, it makes sense to differentiate local residents from tourists. This ... [more ▼]

Activity recommendation systems aims at providing relevant information depending on targeted users' groups. For instance in a city, it makes sense to differentiate local residents from tourists. This research investigates to what extent the anonymized data collected from social networks can be used as a basis for making activity recommendations associated with local residents versus tourists when visiting a public place, such as a museum or gallery. Using rules based on the spatial, temporal and semantics of visited places, we are able to infer if a user is likely to be local or a tourist, based on anonymous sample Foursquare data and place-based semantics retrieved using Google Places API. Using semantics of visited places, it becomes possible to infer additional information about a user based on their movements over space and time. Depending on the kind and frequency of visited places, inferences about the aim of a visit to a location are possible. This analysis could provide information to users in the form of recommendations based on their movements while travelling around an area. This study has been performed using Foursquare check-ins for visitors to the Art Institute of Chicago between March 2010 and January 2011. [less ▲]

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See detailLa temporalité dans les SIG
Hallot, Pierre ULg

Conference (2015, October 22)

La gestion de la temporalité dans les SIG (système d'information géographique). Applications actuelles, modélisation et vision future.

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See detailLes états spatio-temporels d'existence et de présence
Hallot, Pierre ULg; Stewart, Kathleen; Billen, Roland ULg

in Revue Internationale de Géomatique = International Journal of Geomatics and Spatial Analysis (2015), 25(2), 173-196

This paper addresses a new approach to formalize the spatiotemporal relationships between geographical objects that do not exist or that are not present at the time of the analysis. We propose first an ... [more ▼]

This paper addresses a new approach to formalize the spatiotemporal relationships between geographical objects that do not exist or that are not present at the time of the analysis. We propose first an analysis of the spatiotemporal states of existence and presence for a geographical object. Then, we combine the spatiotemporal states to define a comprehensive set of life and motion configuration. The proposed model serves as formal basis to perform spatiotemporal queries by retrieving selected patterns in the life and motion configurations. The research is applied to the organization of a scientific conference, in doing so we are able to define the relationships that exist between an event located in space and time and mobiles objects evolving within the space, i.e. the conference participants. [less ▲]

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See detailSegmentation semi-automatique pour le traitement de données 3D denses : application au patrimoine architectural
Poux, Florent ULg; Hallot, Pierre ULg; Jonlet, Benoît ULg et al

in XYZ : la Revue de l'Association Française de Topographie (2014), 141(36), 69-75

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See detailTowards an Archaeological Information System: improving the core data model
Van Ruymbeke, Muriel ULg; Carré, Cyril ULg; Delfosse, Vincent ULg et al

Conference (2014, April 25)

Grounded on archaeological information modeling works undertaken at the Geomatics Unit of the University of Liege, this paper goes a step further in handling time and function imperfection, interpretative ... [more ▼]

Grounded on archaeological information modeling works undertaken at the Geomatics Unit of the University of Liege, this paper goes a step further in handling time and function imperfection, interpretative sequences and people interacting with historical objects. Designed in 2011, the initial model already gathered both geometrical and historical information. It was partially based on the urban data standard City GML mainly for interoperability purposes. Its specificity, the version concept, allowed multiple geometries experiments. That property enabled us to handle geometrical ambiguity and incompleteness. To validate this model, and in a showcase purpose, a first prototype has been realized. One year later this prototype’s model has been improved to manage in a better way all objects’ versions and possible representations. Until now, this model integrates and manages imperfect archaeological data but only partially: the version concept being only dedicated to express geometric ambiguity or imprecision. Henceforth, with the version notion widening, we propose to encompass function and time imperfection as well. It is an important progress because on an archaeological point of view, time and function are quite generally incomplete, uncertain, imprecise or contradictory. Another enhancement must be highlighted: the agent enlistment. Historical characters, on one hand, and contemporaneous people (like authors, archaeologists etc.) on another hand are key elements of archaeological game pieces. Finally, we will describe the way of structuring versions into interpretative sequences. With those improvements, we wish to carry on feeding the scientific debate as much as drafting Archaeological Information Systems. [less ▲]

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See detailA Spatiotemporal Analysis of Membership: Formalizing the Space-Time Elements of Connection for Groups
Hallot, Pierre ULg; Stewart, Kathleen

in Proceedings of the AAG Annual Meeting (2014)

This research aims to formalize the spatiotemporal relationships of membership between individuals and the groups to which they belong. Specifically, we analyze how the membership to a community evolves ... [more ▼]

This research aims to formalize the spatiotemporal relationships of membership between individuals and the groups to which they belong. Specifically, we analyze how the membership to a community evolves over time considering past, present and future connections. The framework developed for this research is presented using an ontological approach. We demonstrate a specific domain ontology application for spatiotemporal membership using BFO2, an updated version of the Basic Formal Ontology. Key to this work is the representation of membership, modeled through different kinds of mereological relations possible with a group, for example, pre-member, active member, and alumni that capture how membership evolves and changes over time. The semantic web rule language (SWRL) is used to express the different spatiotemporal events that relate to membership and their consequences on membership such as subscription, graduation and reunion events. Mobility events are also included in the model. SWRL supports reasoning using the ontology and studying the evolution of membership between people and their various groups. We use the environment of a university community as an exemplar to develop and test the formalizations. However, the ideas are generalizable to a wide range of spatiotemporal domains, for example, these ideas hold for citizenship modeling or for consumers shopping at certain retail chains. The study of the evolution of membership connections between these entities and groups lends important insights for many different kinds of event planning. [less ▲]

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See detailVIRTUAL LEODIUM: FROM AN HISTORICAL 3D CITY SCALE MODEL TO AN ARCHAEOLOGICAL INFORMATION SYSTEM
Pfeiffer, Michelle ULg; Carré, Cyril ULg; Delfosse, Vincent ULg et al

in Grussenmeyer (Ed.) ISPRS Annals – Volume II-5/W1, 2013 (2013, September 03)

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See detailActes de la Conférence internationale de Géomatique et Analyse Spatiale 2012
Billen, Roland ULg; Binard, Marc ULg; Hallot, Pierre ULg et al

Book published by Unité de Géomatique (2012)

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See detailDeveloping an ontology of space: application to 3D city modeling
Billen, Roland ULg; Zaki, Chams Eddine; Servières, Myriam et al

in Leduc, Thomas; Moreau, Guillaume; Billen, Roland (Eds.) Usage, Usability, and Utility of 3D City models (2012)

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See detailMapping error due to image geometric correction.
Hallot, Eric ULg; Cornet, Yves ULg; Hallot, Pierre ULg

Poster (2012, April)

Nowadays, image processing and GIS tools are more accessible and available to all. Most of diachronical or historical studies use the image geometric correction with several documents like old maps, plans ... [more ▼]

Nowadays, image processing and GIS tools are more accessible and available to all. Most of diachronical or historical studies use the image geometric correction with several documents like old maps, plans or aerial photographs. They are usually based on low-order polynomial equation to perfom these kinds of simplistic uses. Most of commercial softwares provide us a total or by ground control points RMSE but they don’t offer a overview of the spatial error distribution. More this does not guarantee that its significance for the other points of the image. Do not consider these errors can lead to erroneous observations and misinterpretations like historical moving streams or bank erosion rate. Using a least square adjustment (LSA), allow to recalculate the transformation equation from the pairs of control points coordinates. Assuming that residuals are spatially auto-correlated, we can build error vectors whose direction and magnitude symbolize the error at each point of the image. By another way, LSA manage the precision during transformation process by using a stochastic model in addition of the mathematical model during the transformation. This gives us variance on parameters of the transformation. Knowing the precision of all elements and variance/covariance matrix on transformation parameters, we apply variance propagation on the model. As an output, we obtain confidence ellipses on each transformed points, thus a spatial distribution of error for the entire image. Moreover, this leads us to determine statistically if observed movement are significant or not. The represent error is a complex problem that cannot be solved with a quick fix. In this work, we present an interesting example of using well-known topographic methods to solve image processing problems. [less ▲]

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See detailL'identité à travers l'espace et le temps. Vers une définition de l’identité et des relations spatio-temporelles entre objets géographiques.
Hallot, Pierre ULg

Doctoral thesis (2012)

The principal goal of this research is to model object’s evolution in space and time; it implies questioning identity, space and time. First, we define the concept of object spatio-temporal state. This ... [more ▼]

The principal goal of this research is to model object’s evolution in space and time; it implies questioning identity, space and time. First, we define the concept of object spatio-temporal state. This concept allows modelling object identity evolution. Indeed, managing object identity must not be related to the object spatiality. In other words, we assume that the existence of an object is not dependant of its spatial extension. We show that there exist a lot of relationships associated to objects which does not yet exist or which does not exist anymore. We show also that when objects are not visible during an interval of time, it does not imply the lost of their identity. The model we propose aims at providing a framework for non-existent and non-visible objects Then, we study the spatio-temporal interactions between objects. The proposed solution is to define relationships between objects spatio-temporal states. It appears that the proposed set of relationships is a generalized vision of existing spatio-temporal reasoning models. Knowing that space-time continuity is not preserved in qualitative modelling, we apply the dominance theory which aims at retrieving continuous transitions between qualitative states. This development provides formal definitions of possible transition between spatio-temporal states relationships. Logically, the next step is to study the possible evolution of these spatio-temporal states relationships. This leads to the development of a formal model called “life and motion configurations”. This iconic representation gives a simplified view of the spatio-temporal evolution between two objects. It can be used to formalize the relationship between two spatio-temporal histories. In this work, we prove that this language is sufficient to provide spatio-temporal knowledge on moving objects. It determines also a framework in which others spatio-temporal reasoning models can be classified. Based on life and motion configurations, we propose two applications. Firstly, the life and motion configurations are generalised into a set of 25 relationships representing spatio-temporal information with a high level of abstraction. We believe that this set is close to people perception of spatio-temporal information. Secondly, two natural language interpretations of life and motion configurations are proposed; one applied to generalized spatio-temporal relationships, one applied to spatio-temporal predicates used in common French language. [less ▲]

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See detailAdvances in Conceptual Modeling
De Troyer, Olga; Bauzer Medeiros, Claudia; Billen, Roland ULg et al

Book published by Springer-Verlag - LNCS (2011)

ER 2011Workshops FP-UML, MoRE-BI, Onto-CoM, SeCoGIS, Variability@ER, WISM Brussels, Belgium, October 31 - November 3, 2011 Proceedings

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See detailMapping the error due to image geometric correction ?
Hallot, Eric ULg; Hallot, Pierre ULg; Cornet, Yves ULg

Conference (2011, October 14)

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See detailObject existence and presence a core issue in spatio-temporal modelling
Hallot, Pierre ULg

Conference (2010, January 14)

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See detailA pyramidal classification of ST relationship models
Hallot, Pierre ULg; Billen, Roland ULg

in Van de Weghe, Nico; Gottfried, Björn; De Maeyer, Philippe (Eds.) et al Proceedings of the 3th Workshop on Behaviour Monitoring and Interpretation (2009, November 03)

Although intensive works have been devoted to spatiotemporal modeling during the last two decades, there are only a few models dedicated to relationships between two (or more) moving objects. This paper ... [more ▼]

Although intensive works have been devoted to spatiotemporal modeling during the last two decades, there are only a few models dedicated to relationships between two (or more) moving objects. This paper proposes a classification framework of spatiotemporal relationship models based on the ways spatiotemporal histories are analyzed. First, we discuss model conditions of application. Then we propose a classification of spatiotemporal relationship models based on a pyramidal representation of the quantity of extracted information, i.e. the nature and the complexity of provided information, from spatiotemporal histories. This classification aims helping users to choose adequate models for their purposes. The proposed spatiotemporal histories analysis method could lead to the development of new spatiotemporal relationship models. [less ▲]

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