Global ETD Search

51	Measurement of the energy spectrum of the BL Lac object PG1553+113 with the MAGIC telescope in 2005 and 2006 Hengstebeck, Thomas 01 June 2007 (has links) In dieser Doktorarbeit wurden im Rahmen des MAGIC Experimentes neue Datenanalysemethoden implementiert, die sich insbesondere fuer die Analyse von Ereignissen niedriger Gammastrahlungsenergie eignen. Die Methoden konnten erfolgreich in Monte Carlo Studien getestet und auf Beobachtungsdaten des Krebsnebels und der extragalaktischen Gammastrahlungsquelle PG1553+113 angewandt werden. Diese Methoden reichen von ''image cleaning'' Techniken und der Nutzung neuer Bildparameter bis zu fortgeschrittenen g/h-Separations- und Energieabschaetzungsverfahren. Zum ersten Mal wurden die Vorteile von Klassifikations- und Regressionsbaeumen in der Gamma-Astrophysik ausgenutzt, um existierende klassische Methoden zu verbessern. Die Analyse - getestet an Monte Carlo Daten - bewies ihre Zuverlaessigkeit bei der Untersuchung der Gammastrahlungsemission des Krebsnebels, wobei ein hochsignifikanter Exzess im Energiebereich unterhalb 100 GeV in nur 1.7 h nachgewiesen werden konnte. Die Analyse von Daten des BL Lac Objekts PG1553+113 ergab signifikante Exzesse fuer Beobachtungen in den Jahren 2005 und 2006. Das kombinierte alpha-Histogramm zeigt ein Signal mit einer Signifikanz, die 8 sigma ueberschreitet. Bei der weiteren Analyse konnte ein differentielles Energiespektrum fuer die kombinierten Daten aus den Jahren 2005 und 2006 erstellt werden. Der integrale Fluss oberhalb von 200 GeV wurde wie folgt bestimmt: F(> 200 GeV) = (1.7+-0.3) 10^(-12)/(cm^2 s), der spektrale Index betraegt Gamma = 3.6+-0.3. Dieses Spektrum konnte daraufhin verwendet werden, um die (unbekannte) Rotverschiebung von PG1553+113 auf z / In this thesis new data analysis methods for the MAGIC experiment were implemented, which are especially suited for the investigation of low energy gamma-ray events. They were successfully tested by means of Monte Carlo studies and applied to observational data of the Crab Nebula and of the extragalactic gamma-ray source PG1553+113. These methods extend from image cleaning techniques and the utilization of new image parameters to sophisticated g/h-separation and energy estimation approaches. For the first time in gamma-ray astrophysics the advantages of classification and regression trees were exploited in order to improve existing `classical'' methods. The analysis procedure - tested on Monte Carlo data - was demonstrated to be reliable in the investigation of the Crab Nebula gamma-ray emission yielding a significant excess in the energy range below 100 GeV in only 1.7 h observation time. The analysis of data taken on the BL Lac PG1553+113 yielded significant excesses for both years 2005 and 2006. The combined alpha histogram shows a signal in excess of 8 sigma. In the further analysis a spectrum could be derived for the combined data sets of 2005 and 2006. The integral flux above 200 GeV could be derived as F(> 200 GeV) = (1.7+-0.3) 10^(-12)/(cm^2 s), the power-law index was measured to be Gamma = 3.6+-0.3. This spectrum was used to constrain the redshift z of PG1553+113 with the result z Absorption Physik Cherenkov Astronomie Astrophysik Gammastrahlung Aktiver Galaktischer Kern AGN Blazar Rotverschiebung Photon-Photon Extragalaktisches Hintergrundlicht EBL g/h-Separation Random Forest Krebsnebel PG1553+113 Cherenkov physics astronomy astrophysics gamma radiation Active Galactic Nucleus AGN blazar redshift photon-photon absorption Extragalactic Background Light EBL g/h-separation Random Forest Crab Nebula PG1553+113 530 Physik 29 Physik, Astronomie ddc:530
52	乱流太陽系星雲でのダストの生長と微惑星の形成渡邊, 誠一郎 05 1900 (has links) 科学研究費補助金研究種目:一般研究(C) 課題番号:05833001 研究代表者:渡邊誠一郎研究期間:1993-1994年度原始惑星系円盤太陽系形成論惑星集積過程塵微粒子乱流原始太陽系星雲 Protoplanetary Disk Dust Grain Solar Nebula Planetary Accumulation 固体微粒子 Bipolar Outflow 微惑星 Formation of Solar System Turbulence 惑星形成論双極分子流
53	Implementation and Analysis of Co-Located Virtual Reality for Scientific Data Visualization Jordan M McGraw (8803076) 07 May 2020 (has links) <div>Advancements in virtual reality (VR) technologies have led to overwhelming critique and acclaim in recent years. Academic researchers have already begun to take advantage of these immersive technologies across all manner of settings. Using immersive technologies, educators are able to more easily interpret complex information with students and colleagues. Despite the advantages these technologies bring, some drawbacks still remain. One particular drawback is the difficulty of engaging in immersive environments with others in a shared physical space (i.e., with a shared virtual environment). A common strategy for improving collaborative data exploration has been to use technological substitutions to make distant users feel they are collaborating in the same space. This research, however, is focused on how virtual reality can be used to build upon real-world interactions which take place in the same physical space (i.e., collaborative, co-located, multi-user virtual reality).</div><div><br></div><div>In this study we address two primary dimensions of collaborative data visualization and analysis as follows: [1] we detail the implementation of a novel co-located VR hardware and software system, [2] we conduct a formal user experience study of the novel system using the NASA Task Load Index (Hart, 1986) and introduce the Modified User Experience Inventory, a new user study inventory based upon the Unified User Experience Inventory, (Tcha-Tokey, Christmann, Loup-Escande, Richir, 2016) to empirically observe the dependent measures of Workload, Presence, Engagement, Consequence, and Immersion. A total of 77 participants volunteered to join a demonstration of this technology at Purdue University. In groups ranging from two to four, participants shared a co-located virtual environment built to visualize point cloud measurements of exploded supernovae. This study is not experimental but observational. We found there to be moderately high levels of user experience and moderate levels of workload demand in our results. We describe the implementation of the software platform and present user reactions to the technology that was created. These are described in detail within this manuscript.</div> Software Engineering Computer Software Computer Graphics Simulation and Modelling Virtual Reality and Related Simulation Mobile Technologies Networking and Communications Computer-Human Interaction Collaborative Virtual Reality Virtual Reality Collaborative Virtual Reality Networking Networked VR Mulitplayer Multiplayer VR Data Visualization Data Exploration Head Mounted Display Cyberspace Augmented Reality Emerging Technologies Consumer Devices Virtual Environment Virtual Aesthetics Collaborative VR Simulation Training Simulation and Training Colocated Colocated Virtual Environment Immersive Media Immersive Technology Collaborative Tools Educational Virtual Environment Point Cloud Representations Isosurface Representations Mesh Smoothng Supernova Supernovae Supernova Remnant Modeling Astronomy and Astrophysics Cassiopeia N132D E0102 Crab Nebula CAVE CAVE Theater Mobile VR Virtual Classrooms STEM Workload Workload Assessment Tool Presence Engagement Immersion Experience Consequence Simulator sickness Simulator Sickness Questionnaire NASA TLX NASA Task Load Index Unified User Experience Quesionnaire Modified User Experience Questionnaire Oculus Oculus Go Oculus Quest Novel Solutions Optitrack Motive Motion Capture Mocap User Experience Unity3D Game Engine Lidgren Room Scale VR Hall Scale VR Co-location Colocation Virtual Training Collaborative Virtual Environments Shared Virtual Environments Collaboration Whiteboard Mobile Virtual Reality VR HMD LAN UX CSCL UXQ TLX AR VE CVE 3D UI EVE

Page generated in 0.0325 seconds