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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Δορυφορικές μέθοδοι προσδιορισμού θέσης (GPS) για την γεωμετρική διόρθωση δορυφορικών εικόνων

Μυλωνάκης, Μερκούριος 14 February 2012 (has links)
Σε αυτή την εργασία στόχος είναι να συντεθεί μία βάση φωτοσταθερών που θα μπορεί να χρησιμοποιηθεί για την γεωμετρική διόρθωση δορυφορικών εικόνων που έχουν ληφθεί από σαρωτές με παρόμοια χαρακτηριστικά σε διαφορετικές χρονικές στιγμές. Πιο συγκεκριμένα η βάση δεδομένων δημιουργήθηκε με φωτοσταθερά που προσδιορίσθηκαν από δορυφορική εικόνα Landsat–ETM (pixel=15m, παγχρωματικό) ενώ οι συντεταγμένες των φωτοσταθερών μετρήθηκαν στο έδαφος με GPS (φορητό, Garmin 12 ). Η περιοχή μελέτης είναι στο λεκανοπέδιο Αττικής. Τα φωτοσταθερά που χρησιμοποιήθηκαν κατά κανόνα αντιστοιχούσαν σε διασταυρώσεις κεντρικών οδών που αναγνωρίσθηκαν όχι μόνο στην εικόνα αλλά και σε τοπογραφικό χάρτη κλίμακας 1:10.000 προκειμένου να διευκολυνθεί η πρόσβαση στο ύπαιθρο. Η γεωμετρική διόρθωση υλοποιήθηκε με πολυώνυμο δευτέρου βαθμού (μη παραμετρικό μοντέλο στο λογισμικό επεξεργασίας εικόνας) ErMapper και το μέσο τετραγωνικό σφάλμα ήταν 7,01 μέτρα. Στην συνέχεια η πλειονότητα των φωτοσταθερών αναγνωρίσθηκαν και σε δορυφορική εικόνα (VNIR) με χωρική διακριτική ικανότητα 15μ, επιβεβαιώνοντας την δυνατότητα χρήσης της βάσης για την διόρθωση διαχρονικών (multi-temporal) δεδομένων. Προσδιορίσθηκαν οι κανόνες επιλογής φωτοσταθερών για την δημιουργία βάσεως δεδομένων και προσδιορίσθηκαν οικονομοτεχνικά στοιχεία που καθορίζουν το κόστος των εργασιών. / A database of Ground Control Points was established for the geometric correction of multi-temporal satellite imagery. More specifically the high resolution (15 meters ) panchromatic band of a Landsat image was used for the recognition of Ground Control Points, their coordinates were measured on the ground by a hand-held Garmin GPS. The GCPs selected corresponded to main streets intersections that were easily recognized in the 15th meter resolution image. A non parametric method (second order polynomial) was used for the geometric corrections of the images. The resulted RMS was equal to 7,01 meter. Then the majority GCPs were also recognized in an Aster (VNIR) image with resolution 15m.This fact indicated that a GCP database can be used for the corrections of multitemporal imagery (like Aster with revisit time 16 days) that covers Attiki Regions. The rules for the selection of GCPs in order to construct a database were determined as well as the cost of processing for GCP.
62

A Numerical Analysis of Mine Intersections and Support Systems for Stability

Abbasi, Behrooz 01 December 2010 (has links)
AN ABSTRACT OF THE THESIS OF Behrooz Abbasi, for the Master of Science Degree in Mining and Mineral Resources Engineering, at Southern Illinois University Carbondale TITLE: A NUMERICAL ANALYSIS OF MINE INTERSECTIONS AND SUPPORT SYSTEMS FOR STABILITY MAJOR PROFESSOR: Dr. Yoginder P. Chugh Back ground: Partial extraction room-and-pillar mining systems provide about 60 % of the underground coal mined in the USA. This mining system develops 3-way and 4-way intersections. Rock falls related to fatal and nonfatal injuries in the USA for the period 2002 to 2007 identified that about 70% of these falls occur at intersections even though they represent only about 20-25 % of the area mined. A recent study on 2004 to 2008 roof-falls data base (RFDB) for Illinois mines, found that over 80% of these falls occurred at intersections. Thus, there is a significant need to improve stability of coal mine intersections if fatal and nonfatal injuries are to be controlled. The overall goal of this research is to develop an improved scientific understanding of stress distribution and instability around a 4-way intersection. An additional goal is to evaluate primary and secondary support layouts for improved stability around 4-way intersections. The following specific tasks were established for this research. * Perform 3-D numerical analyses to develop a better understanding of stress, strain and displacement distributions and associated instabilities around a 4-way intersection to identify ground support requirements. * Identify primary and secondary supports systems that may be suited to meet ground support requirements in (1) above. * Perform numerical analyses with identified primary and secondary supports installed to assess improvements in stability around an intersection. Analyses results show that pillar ribs across an intersection fail first and lead to progressive failure of immediate roof layers. The failure of immediate roof layers extends about 1.8m. In detail, coal ribs around the intersection corners mostly fail due to tensile stress, while roof and floor strata fail due to shear stresses and rib center fail due to combination of shear and tension mechanism. Primary supports significantly improve stability, but they are not adequate to ensure stability of four-way intersections. Secondary supports are needed to further improve stability of intersections. Also, based on the failure analysis a new secondary support system plan was proposed and analyzed.
63

Orientação semi-automática de imagens CBERS usando rodovias como controle de campo

Scalco, Júlio Cesar [UNESP] 28 August 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-28Bitstream added on 2014-06-13T20:07:43Z : No. of bitstreams: 1 scalco_jc_me_prud.pdf: 6331050 bytes, checksum: 33a0f5c24d636bf10965beb1c69f28f3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nesta pesquisa é proposta uma metodologia para a orientação semi-automática de imagens CBERS usando rodovias como controle de campo. Baseia-se numa estratégia iterativa envolvendo três etapas. Na primeira etapa um operador identifica na imagem as rodovias de controle de campo e fornece alguns pontos sementes, distribuídos grosseira e esparsamente ao longo ou nas imediações das rodovias. Estes pontos sementes são utilizados pelo algoritmo de otimização de programação dinâmica para extrair as rodovias na imagem. Na segunda etapa são estabelecidas correspondências pontuais entre as rodovias de controle e as correspondentes rodovias extraídas na imagem. Na terceira etapa as correspondências pontuais são utilizadas para orientar a imagem usando a DLT (Direct Linear Transformation). As duas últimas etapas do processo são iteradas até que se verifique a estabilização do processo de orientação. Os resultados experimentais possibilitaram verificar que a metodologia proposta foi eficiente com várias imagens teste. Em todos os casos se verificou a convergência do processo de orientação. Além disso, os parâmetros estimados de orientação possibilitaram o registro de rodovias de verificação com acurácia no nível do pixel ou melhor. / In this research is proposed a methodology for semiautomatic CBERS image orientation using roads as ground control. It is based on an iterative strategy involving three steps. In the first step, an operator identifies on the image the ground control roads and supplies along them a few distributed seed points, which could be sparsely and coarsely distributed. These seed points are used by the dynamic programming algorithm for extracting the ground control roads from the image. In the second step, it is established the correspondences between points describing the ground control roads and the corresponding ones extracted from the image. In the last step, the corresponding points are used to orient the CBERS image by using the DLT (Direct Linear Transformation). The two last steps are iterated until the convergence of the orientation process is verified. Experimental results showed that the proposed methodology was efficient with several test images. In all cases the orientation process converged. Moreover, the estimated orientation parameters allowed the registration of check roads with pixel accuracy or better.
64

Design, analysis and manufacture of a Rocprop dome end

Bolton, Jason Charles 16 August 2012 (has links)
M.Ing. / Safety within the mining industry is a primary concern for everyone involved. More specifically, active below-ground stope support for South African Mines is becoming increasingly important due to a renewed emphasis on the safety and well-being of the people actually working underground. It is imperative that all stope support systems are rigorously tested, continuously, both under laboratory conditions and in-situ to prove their performance and manufacturing standards. The Rocprop was initially manufactured in 1995 with the first two hundred props being installed at East Driefontein Consolidated Gold Mine in the Carletonville area. In the three years since the first introduction over three hundred thousand Rocprops have been manufactured and sold to South African Mines with the number steadily increasing. The Rocprop is a tubular support consisting of two tubes — a Ø139mm 'inner' tube and a Ø152mm 'outer' tube. One end of each tube is sealed by dome ends which are welded onto the tube mouths. The two tubes, cut to identical lengths, fit inside one another and extend telescopically during installation. Once the desired height has been reached, leaving enough tube overlapping to ensure the support does not buckle, the wedge is hammered in locking the prop at that height. The water is then removed after which the prop will provide active support of the rock mass above it. One of the components responsible for the Rocprops success is a dome end. This is either a forging or a pressing welded onto each end of the support and allows continual concentric loading throughout the life of the Rocprop. At present the dome ends are pressings, manufactured into hemispheres from 10mm mild steel plate in one action. The reason for the Rocprop's success is its performance characteristics. It's all metal construction, ease of installation, reliability and predictability in both seismic and static conditions, fire resistance, blast resistant, economically viability and versatility have made the prop successful. Reasons for the research were to investigate the dome end forming process in general and to investigate current numerical analysis techniques ability to predict loads during manufacture, the final shape, spring-back and other local deformation areas. Also to investigate alternate manufacturing methods such as cold forming, which provides advantages such as better mechanical properties and higher structural capabilities. The use of alternate materials in the Rocprop manufacture has been an ongoing process for MSP, manufacturer and current licensee holder of the Rocprop. A substitute for the current dome end manufactured from mild steel was investigated. For the substitute to be viable the material should be stronger, weigh less and be cost effective. In depth knowledge about the forming of the dome end at various velocities was gathered, providing information for further optimisation of the component.
65

Validation of the Rock Quality Tunneling Index, Q-system, in underground mine tunneling on a South African platinum mine

Hartman, Wouter 05 March 2007 (has links)
Please read the abstract in the 00front part of this document / Dissertation (MSc (Mining Engineering))--University of Pretoria, 2007. / Mining Engineering / unrestricted
66

The effects of the pressure arch upon multiple seam mining

Hudock, S. D. January 1983 (has links)
The coal fields of Appalachia of many contiguously mineable coal seams. Common practice in mining multiple seams is to extract the seams in a descending order. However, the mining sequence may still be based on seam ownership, availability of the seam and the general economic situation, net on ground control considerations. One of the major ground control mechanisms that must be considered in the design of a mine is the arching of stresses around a previously mined lower seam. This investigation deals with the extent and magnitude of the stresses above an underground opening. The finite element approach was utilized to determine the extent and magnitude of stresses for various widths of mine opening, depths of cover and overburden material. This information can then be used as an approximation of the stresses that may be encountered in an actual mining situation. / Master of Science
67

Re-mining Johannesburg: urban redevelopment through the treatment of acid mine drainage

27 January 2014 (has links)
M.Tech. (Architectural Technology) / The architectural intervention proposes an urban redevelopment along the mining belt of the city of Johannesburg through the treatment of acid mine drainage. The design research includes a network of selected sites located along the Johannesburgmining belt to address the problem of acid mine drainage,as well as to provide solutions for future urban environments. The main solutions to eradicate the acid mine water problem are infrastructural, which in most cases is associatedwith inhumane environments. A design question addressing the marriage between harsh infrast ructure and humane environments is therefore dealt with ,in an attempt to create a self-sustaining architecture in which infrastructure can have an integrative urban function for the future . The dissertation aims to achive a design intervention that will thread the traces of a mining century into this contemporary African city, through an architecture that will grow into the future of the ever-changing and continuously emergent Johannesburg.
68

Osäkerhet vid fotogrammetrisk kartering med UAS och naturliga stödpunkter

Skoog, Elin, Axelsson, Mathilda January 2013 (has links)
En karta är en färskvara som är i ständigt behov av ajourhållning. Ajourhållning görs normalt med traditionella metoder: fotogrammetriska och/eller geodetiska. Men i och med att utvecklingen går framåt har intresset för en ny metod, UAS (Unmanned Aerial Systems), ökat. UAS är en relativt ny fotogrammetrisk metod där obemannade flygfarkoster används. Detta examensarbete har utvärderat vilken osäkerhet vanligt förekommande detaljer i en karta kan få i framställda "produkter" som genererats med hjälp av UAS-bilder som georefererats med naturliga stödpunkter. Produkterna som framställdes var en digital ytmodell och ett ortofoto och togs fram i datorprogrammet Agisoft Photoscan. Bilderna som bearbetades i denna studie erhölls från Swecos UAS-flygning och var tagna över deponiområdet Fågelmyra i Ornäs, Dalarnas län. I den digitala ytmodellen och i ortofotot mättes detaljer in för att sedan kontrolleras mot kontrollpunkter inmätta med nätverks-RTK (Real-Time Kinematic). Studien visade att detaljer inmätta i den digitala ytmodellen och ortofotot resulterade i en osäkerhet på 0,28 m respektive 0,08 m i plan. Varför osäkerheterna skiljer sig mellan den digitala ytmodellen och ortofotot kan ha att göra med att det är svårt att identifiera objekt i den digitala ytmodellen. Utifrån denna studie kan det konstateras att UAS och georeferering med naturliga stödpunkter lämpar sig för kartering av mindre områden. Dessutom kan det konstateras att UAS är effektiv och relativt enkel teknik. / A map is in constant need of being updated. Map updating is normally performed with traditional methods such as photogrammetric and/or geodetic. But by technical development the interest in new methods has increased, like in UAS (Unmanned Aerial Systems). UAS is a relatively new photogrammetric method using unmanned aerial vehicles (UAV). The purpose of this study is to evaluate what uncertainty common details in a map can get in "products" generated from UAS images georeferenced with natural ground control points. The products that were generated was a digital surface model and an orthophoto and was produced in the software Agisoft Photoscan. The images that were processed in this study were obtained from Sweco’s UAS flight and taken over landfill area Fågelmyra in Ornäs, Dalarna county. In the digital surface model and the orthophoto details were measured and controlled against check points surveyed with Network RTK (Real-Time Kinematic). The study has shown that the surveyed details in the digital surface model and ortohophoto resulted in a planimetric uncertainty of 0.28 m and 0.08 m, respectively. The reason for why the uncertainties for the digital surface model and orthophoto are different may be that it is difficult to identify objects in the digital surface model. Based on this study it can be concluded that UAS and georeferencing with natural ground control points is suitable for mapping of smaller areas. In addition, it can be concluded that UAS is efficient and relatively easy technique.
69

Zpracování snímků pořízených pomocí UAV / Processing of images taken from UAV

Ptáček, Ondřej January 2014 (has links)
This diploma thesis deals with the processing and evaluation of the pictures taken by unmanned aerial vehicles - UAV. The introductory part is devoted to the definition, use, applications and types of UAV especially for photogrammetric purposes. Also the software equipment is described, including a description and examples of several types of possible outcomes. Further the measurements, computational works and process of elaboration in used software programs are described. Achieved outcomes of elaboration are also presented. In conclusion, the overall evaluation and assessment of the results of measurement is done of set of points.
70

Exploring the Interface to Aid the Operator’s Situation Awareness in Supervisory Control of Multiple Drones / Utforska gränssnittet för att hjälpa operatörens situationsmedvetenhet vid övervakningskontroll av flera drönare

Sun, Sihan January 2022 (has links)
Unmanned Aerial Vehicles (UAVs), commonly called drones, have been applied in manifold fields recently. With the development of UAV autonomy, the next generation of drone applications is moving towards team-based, multi-drone operations. This also promotes the transition of the operator role to the supervisory control of multiple UAVs. Situation awareness (SA) is a significant concept in this aspect to evaluate human performance in complex systems. This thesis work proposes a human-system interface for monitoring multiple autonomous UAVs simultaneously by a single operator, and investigates how to decrease the impact of task switching among different UAVs on the operator’s SA. Tasks in the context of fleet mission control are defined to be of different levels of urgency. Several design strategies have been concluded to address the research question. In conclusion, the usage of similar interface layouts between different tasks is effective to generally decrease the impact of task switching. The alert system with appropriate design is a specific factor in mitigating the impact of task switching towards higher urgency tasks/interfaces. Moreover, the reasonable division of areas of the interface and proper presentation of information by their importance are significant, especially for task switching towards lower urgency tasks/interfaces. / Unmanned Aerial Vehicles (UAV), vanligtvis kallade drönare, har använts i många områden nyligen. Med utvecklingen av UAV-autonomi, går nästa generation av drönarapplikationer mot teambaserad, multi-drönarverksamhet. Detta främjar också övergången av operatörsrollen till övervakande kontroll av flera UAV. Situationsmedvetenhet (SA) är ett betydelsefullt koncept i denna aspekt för att utvärdera mänsklig prestation i komplexa system. Detta examensarbete föreslår ett gränssnitt mellan människa och system för att övervaka flera autonoma UAV:er samtidigt av en enda operatör, och undersöker hur man kan minska effekten av uppgiftsbyte mellan olika UAV:er på operatörens SA. Uppgifter i samband med kontroll av flottans uppdrag definieras till att vara av olika brådskande nivå. Flera designstrategier har tagits fram för att ta itu med forskningsfrågan. Sammanfattningsvis är användningen av liknande gränssnittslayouter mellan olika uppgifter effektivt för att generellt minska effekten av uppgiftsbyte. Varningssystemet med lämplig design är en specifik faktor för att mildra effekterna av uppgiftsbyte mot mer brådskande uppgifter/gränssnitt. Dessutom är den rimliga uppdelningen av områden i gränssnittet och korrekt presentation av information efter deras betydelse betydande, särskilt för uppgiftsbyte mot mindre brådskande uppgifter/gränssnitt.

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