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GBAS ionospheric threat model assessment for category I operation in the Korean region / Minchan Kim in GPS solutions, vol 19 n° 3 (July 2015)  

Public [article]  inGPS solutions > vol 19 n° 3 (July 2015) . - pp 443 - 456 Titre : GBAS ionospheric threat model assessment for category I operation in the Korean region Type de document : Article/Communication Auteurs : Minchan Kim, Auteur ; Yunjung Choi, Auteur ; Hyang-Sig Jun, Auteur ; Jiyun Lee, Auteur Année de publication : 2015 Article en page(s) : pp 443 - 456 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Corée du sud [Termes IGN] gradient ionosphèrique [Termes IGN] perturbation ionosphérique [Termes IGN] système d'extension au sol Résumé : (auteur) During extreme ionospheric storms, anomalous ionospheric gradients can become high enough to affect Global Navigation Satellite Systems (GNSS) Ground-Based Augmentation Systems (GBAS) and to threaten the safety of GBAS users. An ionospheric anomaly threat model for the Conterminous United States (CONUS) was developed based on extreme ionospheric gradients observed in CONUS during the last solar maximum period (2000–2004). However, in order to understand and mitigate ionosphere threats occurring in different geographical regions, ionospheric anomaly threat models have to be established for the relevant regions. To allow the certification of a GBAS ground facility in South Korea, a Korean ionospheric anomaly threat model must be determined. We describe the method of data analysis that was used to estimate ionospheric spatial gradients. Estimates of anomalous gradients in the Korean region were used to define and build an ionospheric anomaly threat model for this region. All gradient estimates obtained using Korean GNSS reference network data for potential ionospheric storm dates from 2000 to 2004 were included in this threat space. The maximum spatial gradient within this threat space is 160 mm of delay per km of user separation, which falls well within the bounds of the current ionospheric threat model for CONUS. We also provide a detailed examination of the two largest ionospheric spatial gradient events observed in this study, which occurred on November 10, 2004, and November 6, 2001, respectively. Numéro de notice : A2015-463 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0404-6 En ligne : https://doi.org/10.1007/s10291-014-0404-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77144 [article]

Multi-criteria evaluation and least-cost path analysis for optimal haulage routing of dump trucks in large scale open-pit mines / Yunjung Choi in International journal of geographical information science IJGIS, vol 23 n°11-12 (november 2009)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 23 n°11-12 (november 2009) . - pp 1541 - 1567 Titre : Multi-criteria evaluation and least-cost path analysis for optimal haulage routing of dump trucks in large scale open-pit mines Type de document : Article/Communication Auteurs : Yunjung Choi, Auteur ; H.D. Park, Auteur ; C. Sunwoo, Auteur ; K. Clarkes, Auteur Année de publication : 2009 Article en page(s) : pp 1541 - 1567 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse multicritère [Termes IGN] chemin le moins coûteux, algorithme du [Termes IGN] mine [Termes IGN] outil d'aide à la décision [Termes IGN] recherche du chemin optimal, algorithme de [Termes IGN] système d'information géographique [Termes IGN] transport routier [Termes IGN] véhicule automobile Résumé : (Auteur) A new raster-based GIS model that combines multi-criteria evaluation and least-cost path analysis was developed to determine the optimal haulage routes of dump trucks in large scale open-pit mines. The model logic can consider multiple criteria simultaneously (i.e. speed, water body, ore body, curve, visibility, haul road maintenance) and can rate the adverse factor scores of truck movement using fuzzy membership functions. After establishing the weights of five factors by pairwise comparisons, the average adverse score grid can be generated by the weighted linear combination of factor and constraint scores. New software, called Dump Traveler, was implemented to improve the availability of the developed model. An application to the Roto South pit in the Pasir open-pit coal mine, Indonesia, showed that the software can provide rational solutions to determine the optimal routes on truck haulage operations. Moreover, the layout of available haul roads can be evaluated to consider the trade-off between road maintenance costs and the potential for traffic jams. Variations of weights for factors were found to be sensitive to the optimal haulage routes determined by least-cost path analysis. The software provides both optimal routes on truck haulage operations and approximately estimated travel times along the routes, therefore it can support other truck dispatching software that mainly considers scheduling problems. Copyright Taylor & Francis Numéro de notice : A2009-520 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802385245 En ligne : https://doi.org/10.1080/13658810802385245 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30149 [article]

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