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Multi-method monitoring of rockfall activity along the classic route up Mont Blanc (4809 m a.s.l.) to encourage adaptation by mountaineers / Jacques Mourey in Natural Hazards and Earth System Sciences, vol 22 n° 2 (February 2022)  

Public [article]  inNatural Hazards and Earth System Sciences > vol 22 n° 2 (February 2022) . - pp 445 - 460 Titre : Multi-method monitoring of rockfall activity along the classic route up Mont Blanc (4809 m a.s.l.) to encourage adaptation by mountaineers Type de document : Article/Communication Auteurs : Jacques Mourey, Auteur ; Pascal Lacroix, Auteur ; Pierre-Allain Duvillard, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 445 - 460 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] capteur actif [Termes IGN] capteur non-imageur [Termes IGN] carte thématique [Termes IGN] détection de changement [Termes IGN] éboulement [Termes IGN] modèle numérique de terrain [Termes IGN] Mont-Blanc, massif du [Termes IGN] onde sismique [Termes IGN] pergélisol [Termes IGN] prévention des risques [Termes IGN] risque naturel [Termes IGN] saison [Termes IGN] sismologie [Termes IGN] surveillance géologique [Termes IGN] température de l'air Résumé : (auteur) There are on average 35 fatal mountaineering accidents per summer in France. On average, since 1990, 3.7 of them have occurred every summer in the Grand Couloir du Goûter, on the classic route up Mont Blanc (4809 m a.s.l.). Rockfall is one of the main factors that explain this high accident rate and contribute to making it one of the most accident-prone areas in the Alps for mountaineers. In this particular context, the objective of this study is to document the rockfall activity and its triggering factors in the Grand Couloir du Goûter in order to disseminate the results to mountaineers and favour their adaptation to the local rockfall hazard. Using a multi-method monitoring system (five seismic sensors, an automatic digital camera, three rock subsurface temperature sensors, a traffic sensor, a high-resolution topographical survey, two weather stations and a rain gauge), we acquired a continuous database on rockfalls during a period of 68 d in 2019 and some of their potential triggering factors (precipitation, ground and air temperatures, snow cover, frequentation by climbers). At the seasonal scale, our results confirm previous studies showing that rockfalls are most frequent during the snowmelt period in permafrost-affected rockwalls. Furthermore, the unprecedented time precision and completeness of our rockfall database at high elevation thanks to seismic sensors allowed us to investigate the factors triggering rockfalls. We found a clear correlation between rockfall frequency and air temperature, with a 2 h delay between peak air temperature and peak rockfall activity. A small number of rockfalls seem to be triggered by mountaineers. Our data set shows that climbers are not aware of the variations in rockfall frequency and/or cannot/will not adapt their behaviour to this hazard. These results should help to define an adaptation strategy for climbers. Therefore, we disseminated our results within the mountaineering community thanks to the full integration of our results into the management of the route by local actors. Knowledge built during this experiment has already been used for the definition and implementation of management measures for the attendance in summer 2020. Numéro de notice : A2022-181 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.5194/nhess-22-445-2022 En ligne : https://doi.org/10.5194/nhess-22-445-2022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99859 [article]

Everyday space–time geographies: using mobile phone-based sensor data to monitor urban activity in Harbin, Paris, and Tallinn / R. Ahas in International journal of geographical information science IJGIS, vol 29 n° 11 (November 2015)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 29 n° 11 (November 2015) . - pp 2017 - 2039 Titre : Everyday space–time geographies: using mobile phone-based sensor data to monitor urban activity in Harbin, Paris, and Tallinn Type de document : Article/Communication Auteurs : R. Ahas, Auteur ; Y. Yuan, Auteur ; Martin Raubal, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 2017 - 2039 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] capteur non-imageur [Termes IGN] données localisées des bénévoles [Termes IGN] surveillance de l'urbanisation [Termes IGN] téléphonie mobile Résumé : (Auteur) This paper proposes a methodology for using mobile telephone-based sensor data for detecting spatial and temporal differences in everyday activities in cities. Mobile telephone-based sensor data has great applicability in developing urban monitoring tools and smart city solutions. The paper outlines methods for delineating indicator points of temporal events referenced as ‘midnight’, ‘morning start’, ‘midday’, and ‘duration of day’, which represent the mobile telephone usage of residents (what we call social time) rather than solar or standard time. Density maps by time quartiles were also utilized to test the versatility of this methodology and to analyze the spatial differences in cities. The methodology was tested with data from cities of Harbin (China), Paris (France), and Tallinn (Estonia). Results show that the developed methods have potential for measuring the distribution of temporal activities in cities and monitoring urban changes with georeferenced mobile phone data. Numéro de notice : A2015-618 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1063151 En ligne : https://doi.org/10.1080/13658816.2015.1063151 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78087 [article]

#Earthquake: Twitter as a distributed sensor system / Andrew Crooks in Transactions in GIS, vol 17 n° 1 (February 2013)  

Public [article]  inTransactions in GIS > vol 17 n° 1 (February 2013) . - pp 124 - 147 Titre : #Earthquake: Twitter as a distributed sensor system Type de document : Article/Communication Auteurs : Andrew Crooks, Auteur ; Arie Croitoru, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 124 - 147 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] acquisition de données [Termes IGN] capteur non-imageur [Termes IGN] contenu généré par les utilisateurs [Termes IGN] diffusion de l'information [Termes IGN] épicentre [Termes IGN] Etats-Unis [Termes IGN] production participative [Termes IGN] séisme [Termes IGN] surveillance géologique [Termes IGN] Twitter Résumé : (Auteur) Social media feeds are rapidly emerging as a novel avenue for the contribution and dissemination of information that is often geographic. Their content often includes references to events occurring at, or affecting specific locations. Within this article, we analyze the spatial and temporal characteristics of the twitter feed activity responding to a 5.8 magnitude earthquake which occurred on the East Coast of the United States (US) on August 23, 2011. We argue that these feeds represent a hybrid form of a sensor system that allows for the identification and localization of the impact area of the event. By contrasting this with comparable content collected through the dedicated crowdsourcing ‘Did You Feel It?’ (DYFI) website of the U.S. Geological Survey we assess the potential of the use of harvested social media content for event monitoring. The experiments support the notion that people act as sensors to give us comparable results in a timely manner, and can complement other sources of data to enhance our situational awareness and improve our understanding and response to such events. Numéro de notice : A2013-044 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01359.x Date de publication en ligne : 09/10/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01359.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32182 [article]

Ten years of technology advancement in remote sensing and the research in the CRC-AGIP in GCE / Y. Zhang in Geomatica, vol 64 n° 2 (June 2010)  

Public [article]  inGeomatica > vol 64 n° 2 (June 2010) . - pp 173 - 189 Titre : Ten years of technology advancement in remote sensing and the research in the CRC-AGIP in GCE Type de document : Article/Communication Auteurs : Y. Zhang, Auteur Année de publication : 2010 Article en page(s) : pp 173 - 189 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection [Termes IGN] capteur imageur [Termes IGN] capteur non-imageur [Termes IGN] cartographie par internet [Termes IGN] extraction automatique [Termes IGN] instrument aéroporté [Termes IGN] télédétection aérienne [Termes IGN] télédétection spatiale [Termes IGN] traitement d'image Résumé : (Auteur) This paper briefly reviews the development of remote sensing technologies in the last ten years, including the development of optical, radar, and laser sensors and the trend of remote sensing software development. It also introduces some of the research activities and achievements of the Canada Research Chair Laboratory in Advanced Geomatics Image Processing (CRC-AGIP Lab) in the Department of Geodesy and Geomatics Engineering (GGE) at the University of New Brunswick (UNB). According to literature review and our research experience, we have concluded that the “bottle neck” of remote sensing is still the lack of software tools for effective information extraction from remote sensing data, especially after the rapid advancement of remote sensing sensor technologies in the last ten years and the increased demand for quickly updated, accurate geo-spatial information. Numéro de notice : A2010-386 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.5623/geomat-2010-0019 En ligne : https://cdnsciencepub.com/doi/abs/10.5623/geomat-2010-0019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30580 [article]

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035-2010021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

The Swiss trolley / Ralph Glaus (2006)  

Public Titre : The Swiss trolley : a modular system for track surveying Type de document : Rapport Auteurs : Ralph Glaus, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2006 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 70 Importance : 184 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-13-0 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] capteur imageur [Termes IGN] capteur non-imageur [Termes IGN] données localisées [Termes IGN] filtre de Kalman [Termes IGN] fonction spline [Termes IGN] fusion de données [Termes IGN] GPS en mode cinématique [Termes IGN] GPS en mode différentiel [Termes IGN] GPS-INS [Termes IGN] lissage de données [Termes IGN] navigation à l'estime [Termes IGN] odomètre [Termes IGN] positionnement absolu [Termes IGN] précision millimétrique [Termes IGN] prise de vue terrestre [Termes IGN] réseau ferroviaire [Termes IGN] surveillance d'ouvrage [Termes IGN] tachéomètre électronique [Termes IGN] transport ferroviaire Index. décimale : 30.70 Navigation et positionnement Résumé : (Auteur) Modern railway infrastructure requires accurate, absolute referenced spatial data for project planning, construction and maintenance. On the one hand, passenger safety and travel comfort depend to a large extent on accurate tracks. On the other hand, absolute referenced coordinates of railway assets facilitate data exchange between railway operators and third parties. In addition, time slots for maintenance are short, due to the high volumes of traffic on major railway lines. Thus, flexible surveying systems are required yielding accurate data within a short time. The multi-sensor platform Swiss Trolley, which offers such a flexible system, copes with absolute referenced spatial data. The platform is mounted on a track vehicle. This allows for a complete description of the track environment in kinematic mode with a minimum of interference time with regular traffic. The Swiss Trolley features a modular design. A basic module for assessing track key parameters such as chainage, cant, twist, gradients and track gauge covers monitoring tasks on construction sites. A positioning module integrating GPS or total stations allows for the determination of the track axis. A further scan module can be used to generate absolute referenced point clouds in the track environment. This work compiles the development steps of the Swiss Trolley. Relevant side conditions re-garding track surveying, coming from track geometry and the railway operators are summarised and state-of-the-art systems are reviewed. Based on these premises, a niche for Swiss Trolley applications is defined. Sensors providing geometric data in the track environment are evaluated in regard to their suitability and error behaviour. The key problem of the trolley positioning consists in determining the six degrees of freedom of the multi-sensor platform at any point in time. The chosen kinematic approach asks for a careful treatment of time constraints. Each data string coming from a specific sensor must own an accurate time tag. Kinematic surveys at walking speed with subcentimetric accuracy require time tags with millisecond accuracy. The incorporated sensors were investigated regarding their error behaviour. Calibration issues are addressed and approaches for the bias determination are presented. Models for correcting collimation errors and nuisance accelearations are given for the pendulum inclination sensors used. Moreover, emphasis was placed on biases emerging at kinematic surveys for the particular optical total station used. Reduction models for the laser scanner data are proposed and calibration procedures providing intrinsic orientation and latency parameters are given. A kinematic model for Swiss Trolley surveys based on the Frenet base system and its canonical representation was developed. Explicit formulae are given for runs on geometric elements dominating in the railway track environment. For the mutual data processing, a loosely coupled filter concept is proposed consisting of data pre-processing, synchronisation and filtering steps. The core of data processing is a Kalman filter, estimating vehicle and track states in an absolute or a relative reference frame. By means of the filter approach, the observations of the involved sensors can be integrated in a spatial model. Individual filter runs can be assembled by an additional merge step. Merged runs in up and down direction allow for a quality assessment and also allow for the monitoring of eventually remaining biases such as a boresight misalignment or inclination sensor zero point offsets. Positioning accuracies for the static and kinematic case were assessed on the one hand by the comparison of up and down runs. On the other hand, comparisons were carried out with independently measured reference data. The static error behaviour of the Swiss Trolley could be evaluated by using a slab track alignment. Submillimetric positioning accuracies were obtained in combination with high-precision total stations. Kinematic positioning accuracy mainly depends on the positioning sensor used. Optical total stations providing synchronised angle and distance data allow for subcentimetric positioning. High-precision DGPS position-ing yields subcentimetric accuracy for the horizontal component. The typical vertical accuracy is better than two centimetres. The integrated longitudinally mounted inclination sensor slightly augments the mere GPS solution. The attitude determination of the platform is a result of the combined data treatment. For GPS surveys, the typical pitch angle accuracy is two mrad. Yaw angles essentially correspond to the derivation of the trajectory with respect to the covered path and are determined with one mrad accuracy. Roll angle accuracy is dominated by the inclination sensor measurements across the track. The typical accuracy is 0.3 mrad. For the scan module, laser dots in the absolute reference frame are degraded by the uncertainty of the trajectory and the platform attitude amplified by a geometry-depending lever. The absolute accuracy of such a dot is three centimetres using a time-of-flight laser scanner. Relative accuracy between two adjacent dots amounts to five millimetres. The Swiss Trolley was successfully applied on numerous assignments. Adaptations for the multi-sensor platform exist for tunnel site locomotives and road-vehicles. Note de contenu : 1 Introduction 2 Track Geometry 2.1 Nominal Geometries 2.1.1 Introduction 2.1.2 Horizontal Layout 2.1.3 Vertical Layout 2.2 Rules and Standards of Different Countries 2.2.1 Horizontal Layout 2.2.2 Vertical Layout 2.2.3 Cant 2.3 Kinematic Model of Motion 2.3.1 Kinematics in the Frenet System 2.3.2 Canonical Representation of the Most Common Track Curves 2.4 Remarks on Track Accuracy 2.4.1 General Remarks 2.4.2 Relative and Absolute Accuracy of a Track 2.5 Methods for Track Surveying 2.5.1 Overview 2.5.2 Relative Track Surveying 2.5.3 Absolute Track Surveying 2.5.4 Selected Track-Surveying Systems 2.5.5 The Swiss Trolley - Finding the Niche 3 Potentials and Limitations of a Kinematic Track-Surveying System 3.1 Kinematic Surveying 3.2 Absolute Position Fixing 3.2.1 GNSS 3.2.2 Tracking Total Stations 3.3 Dead Reckoning 3.3.1 Inertial Navigation Systems (INS) 3.3.2 Yaw Rates by Chord Techniques 3.3.3 Odometers 3.3.4 Height Determination by an Inclination Sensor 3.4 Attitude Determination 3.5 Kinematic Surveys of the Railway Inventory 3.5.1 Track Gauge Measuring Systems 3.5.2 Laser Scanners 3.5.3 3D Cameras 3.5.4 Ground Penetration Radar (GPR) 3.6 Synchronisation 3.7 Modelling 3.8 Transformation 4 The Track-Surveying Trolley 4.1 Introduction 4.1.1 Development 4.1.2 Concept 4.2 Data Acquisition 4.2.1 Electronic Box 4.2.2 A/D Conversion 4.2.3 Data Synchronisation 4.3 Reconstruction 4.4 Inclination Sensors 4.4.1 Sensor Characteristics 4.4.2 Calibration of Characteristic Curve 4.4.3 Temperature Influences 4.4.4 Corrections for Non-Orthogonalities (Collimation Error) 4.4.5 Dynamic Behaviour of the Inclination Sensor 4.4.6 Transformation of the Inclination Angles into the Body-System 4.5 Track Gauge Measuring System 4.5.1 Characteristics and Measuring Principle of the Track Gauge Measuring System 4.5.2 Calibration 4.6 Odometers 4.6.1 Characteristics and Calibration 4.7 Integration of Tracking Total Stations 4.7.1 Characteristics 4.7.2 Common Total Station Biases 4.7.3 Deflections of the Vertical 4.7.4 Surveys in Canted Sections 4.7.5 Synchronisation of Distances and Angles 4.7.6 Internal Tacheometer and Radio Latencies 4.8 Integration of GPS 4.8.1 Characteristics 4.8.2 NMEA Data 4.9 Boresight Calibration of Prism and Antenna Phase Centre 4.10 Laser Scanners 4.10.1 Characteristics 4.10.2 Model 4.10.3 Yaw Angle Correction 4.10.4 Evaluation of the Laser Scanner Precision 4.10.5 Variance Propagation for a Given Scanner Arrangement 4.10.6 Kinematic Calibration of Rmb, xmb and the Latency 5 Data Processing 5.1 Introduction 5.2 Post-Processing Software Concept 5.3 Data Preprocessing 5.3.1 Blunder Labelling 5.3.2 Reduction, Model 5.3.3 Linear Filters 5.3.4 Synchronisation 5.3.5 Reduction to the Centre Line of the Track 5.4 Trajectory Smoothing by a Kalman Filter 5.4.1 Discrete Kalman Filter 5.4.2 Backward Filter and Smoother 5.4.3 Absolute Model 5.4.4 Relative Model 5.5 Smoothing Splines 5.5.1 Smoothing Splines with First Derivatives 5.5.2 Comparison between Kalman Filter and Smoothing Splines 5.6 Merging Trajectories 5.6.1 Strategies for Merging 5.6.2 Chaining the Pieces 5.6.3 Merging 5.6.4 Linking Scans to Merged Trajectories 6 Applications 6.1 Slab Track Alignment 6.2 Kinematic Track Axis Surveys 6.2.1 Comparison between Forward Filter, Backward Filter and Smoother 6.2.2 Filter Tuning 6.2.3 Comparison between Absolute and Relative Model 6.2.4 The Influence of Inclinometer Measurement on GPS Heights 6.2.5 The Smoother in Action - GPS Example 6.2.6 The Smoother in Action - Total Station Example 6.3 Kinematic Scanning 7 Conclusions Numéro de notice : 15261 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-70.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55115

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
15261-01	30.70	Livre	Centre de documentation	Géodésie	Disponible
15261-02	30.70	Livre	Centre de documentation	Géodésie	Disponible

Indexation multidimensionnelle de bases de données capteur temps-réel et spatiotemporelles / G. Noel in Ingénierie des systèmes d'information, ISI : Revue des sciences et technologies de l'information, RSTI, vol 10 n° 4 (juillet -août 2005)

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Manual of remote sensing, 1. Volume 1 Theory, instruments and techniques / Rob Reeves (1975)

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