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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.
41

Virtual Reality sickness during immersion: An investigation ofpotential obstacles towards general accessibility of VR technology

Lu, Dongsheng January 2016 (has links)
People call the year of 2016 as the year of virtual reality. As the world leading tech giants are releasing their own Virtual Reality (VR) products, the technology of VR has been more available than ever for the mass market now. However, the fact that the technology becomes cheaper and by that reaches a mass-market, does not in itself imply that long-standing usability issues with VR have been addressed. Problems regarding motion sickness (MS) and motion control (MC) has been two of the most important obstacles for VR technology in the past. The main research question of this study is: “Are there persistent universal access issues with VR related to motion control and motion sickness?” In this study a mixed method approach has been utilized for finding more answers related to these two important aspects. A literature review in the area of VR, MS and MC was followed by a quantitative controlled study and a qualitative evaluation. 32 participants were carefully selected for this study, they were divided into different groups and the quantitative data collected from them were processed and analyzed by using statistical test. An interview was also carried out with all of the participants of this study in order to gather more details about the usability of the motion controllers used in this study. The results of this study has validated several existing frameworks for VR. And in conclusion, this study has also shown that both previous motion sickness experiences and gender factors weren’t significant in terms of general accessibility issues on PCVR platforms. There are hints showing that the VR technology on PC platform could be universal accessible, since both of the quantitative and qualitative results has provided some evidences supporting this finding. However, more similar studies need to be carried out in order to identify more possible factors that would give an impact on user experiences in VR. The results of this study has also given implications of that today’s VR technology is developing on the right track and it could slowly become adopted by the mainstream and mass-market in the future.
42

Communication tool in virtual reality – A telepresence alternative : An alternative to telepresence – bringing the shared space to a virtual environment in virtual reality

Ekström, Marcus January 2017 (has links)
Videoconferencing is one of the most common telepresence methods today and educational videos is rising in popularity among distance learners. Traditional videoconferencing is unable to convey gestures and mutual eye contact between participants. This study aim to propose a Virtual Reality telepresence solution using game engines. A literature study confirmed the effectiveness achieved in VR is comparable to the effectiveness in face-to-face meetings. The suggested solution implements whiteboard functionality from a real-life perspective, confirming it is possible to include new functionality and directly transfer old functionality to the VR system from the communication systems today. The system was evaluated based on the response time, packet loss, bandwidth, frame rate and through user tests. The evaluation shows it is possible to design a telepresence system with VR capable of passing the Turing Test for Telepresence. The participants of the user tests did not experience discomfort and they were positively inclined to the telepresence system. Though, discomfort may emerge if the VR character is used with a common office workstation. Future studies in this topic would involve modifications of the third person camera, making the head's rotation follow the direction of the camera view and implementing movable eye pupils on the VR character using the upcoming eye-tracking accessory.
43

Virtual Reality's Effect on Engagement in Educational Games

Rödström, Herman, Fredriksson, Pontus January 2017 (has links)
This thesis explores how virtual reality solutions affect children in their learning through educational games. The goal is to improve educational games in terms of how engaging they are. Therefore, a game was developed for both desktop monitors and VR, some children played both versions and were then interviewed. The collected data indicates that VR engages the pupils more, however it does not seem to necessarily make them learn more. This may be in part because of VR’s novelty, only gaining a mainstream status in the recent years. / Denna uppsats undersöker hur virtuell verklighet (VR) påverkar barns lärande genom utbildningsspel. Målet är att förbättra utbildningsspel för att öka elevernas engagemang. Därför utvecklades ett spel för både datorskärmar och VR-glasögon, några barn fick spela båda versionerna och blev därefter intervjuade. Resultatet av undersökningen indikerar att VR ökar elevernas engagemang, men inte nödvändigtvis att de lär sig mer. Detta kan delvis bero på att VR är relativt nytt och endast börjat bli allmänt förekommande under de senaste åren.
44

Algal Remediation on the HTC Process Liquid of Food Waste

Dilanyan, Shoghik 10 September 2021 (has links)
No description available.
45

Manipulating Control-Display Ratios in Room-Scale Virtual Reality

Andersson, Karl January 2017 (has links)
This study examined how reduced control-display ratios on motion-tracked handheld controllers in virtual reality affected user immersion and sense of control. 24 participants played a puzzle game in virtual reality using one of three control-display ratios: one normal, and two that were reduced using the “Go-Go” technique. Results indicate that the control-display ratio can be reduced drastically while retaining user immersion and sense of control, but that the effectiveness of this seems to differ between individuals and is heavily influenced by previous experiences. Even so, these results could be of use for future virtual reality interaction designers as well as researchers studying the senses of vision and proprioception. / Den här studien undersökte hur sänkta control-display-förhållanden på handhållna kontroller i virtual reality påverkade användares inlevelse och upplevda kontroll. 24 deltagare spelade ett pusselspel i virtual reality med en av tre control-display-förhållanden: en normal, och två som var sänkta med "Go-Go"-metoden. Resultaten indikerar att control-display-förhållandet kan sänkas markant utan att förlora användarens inlevelse eller upplevda kontroll, men till vilken grad detta sker tycks variera mellan individer och även påverkas av tidigare erfarenheter. Trots detta kan dessa resultat vara till nytta för framtida interaktionsdesigners i virtual reality samt för forskare som studerar sinnena syn och proprioception.
46

AN EXPERIMENTAL STUDY OF THE EFFECTS OF SURFACE ROUGHNESS AND SURFACTANT ON POOL BOILING OF NANOFLUIDS

Hamda, Mohamed 11 1900 (has links)
The use of nanofluids as heat transfer fluids has received a lot of attention from the heat transfer research community. Due to the increased thermal conductivity of nanofluids over their base fluids, the number of nanofluids scientific publications increased significantly in the past decade. The effects of the heated surface roughness, nanoparticles and surfactant concentrations on pool boiling of nanofluids have been thoroughly investigated. However, contradicting findings have been observed under what appeared to similar test conditions. In this experimental investigation, two boiling surfaces have been prepared with an average surface roughness of 6 and 60 nm using high precision machining. Alumina Oxide-Water based nanofluids have been used in this investigation. The initial nanoparticle size reported by the manufacturer is 10 nm. The nanoparticles concentration has been kept at 0.05 wt. %. A Sodium Dodecylbenzenesulfonate (SDBS) surfactant has been added to the nanofluids in order to improve its stability. Results showed that the nanofluids boiling performance depended on the boiling surface roughness. The heat transfer coefficient (HTC) obtained in the case of the smooth, mirror finished surface showed an enhancement of 205% with respect to pure water. This trend was reversed in the case of the rough surface which is believed to be due to significant nanoparticles deposition. The HTC obtained with the rough surface was 12% lower than that of pure water. The effect of the surfactant concentration on nanoparticles deposition has been investigated by changing the surfactant concentration from 0.1 to 1.0 wt. %. In the case of the rough surface, the increase of surfactant concentration was found to reduce the formation of the nanoparticles deposition layer. The HTC obtained with the higher surfactant concentration was increased by 46 %. The effect of nanoparticles concentration on the smooth surface shows an unexpected trend of 20 % reduction of the transfer rate of the nanofluids coupled with the increase of the nanoparticle concentration from 0.05 to 0.1 wt. %. However all concentrations showed heat transfer enhancement with respect to pure water. The minimum heat transfer coefficient ratio enhancement was 11 % using 0.1 wt. % nanofluids with respect to pure water. Since nanoparticles deposition has been observed and attributed to micro-layer evaporation, an investigation has been carried out to examine the nucleation process during the pure water and nanofluids pool boiling. The bubble growth rate in both cases was analyzed at different wall degrees of superheat ranging from 104.3 to 105.9 ºC. In addition, the bubble departure diameter and frequency have been measured and compared for both cases. The nanofluid bubble size was about 80 % smaller than that of pure water. The nanofluid bubble departure had almost constant frequency of 500 Hz over the range of wall superheats whereas the maximum bubble frequency in the case of pure water was 22.72 Hz. / Thesis / Master of Applied Science (MASc)
47

A new traversal method for virtual reality: overcoming the drawbacks of common methods

Smink, Karl A 01 May 2020 (has links)
One of the biggest issues facing VR as a platform is the limitation of the user’s physical space. Not everyone has a lab, empty warehouse, or open space in their home or office, and even if they do, the hardware also limits the physical space the user can take advantage of. Fitting the entirety of the environment within few square meters is a strict limitation for many applications. A method of moving the user within a larger space is needed, but current methods come with drawbacks. Developing a new movement method that avoids these drawbacks will help ensure a better experience for the user.
48

企業自創品牌歷程與影響因素解析-以法藍瓷與宏達電為例 / An analysis of enterprises on building self-owned brand innovation in Taiwan and its impacting factors ---cases on Franz and hTC

蔡佩純, Tsai, Pei Chun Unknown Date (has links)
本研究旨在研究台灣企業如何由製造代工(OEM)/設計委託(ODM)代工階段走上自創品牌,以本研究架構為分析基礎,探討不同產業下自創品牌成功企業之案例,進而發現或歸納影響其自創品牌成功之主要因素為何,提供給目前身處於OEM或ODM企業在有心轉往自有品牌發展時,在擬訂未來經營策略時,能有所依循方向。 本研究以定性方法進行個案研究分析,透過次級資料的整理與個案訪談完成撰寫內容,個案訪談公司共計兩家,依序為法藍瓷與宏達電。依據文獻探討與個案訪談結果,整理出四項研究分析構面,解構個案公司自創品牌成功之影響因素,此四構面為產業環境、營運範疇、事業網路與核心資源,透過四構面的整理分析,能有助於外界對於企業自創品牌決策背後之組織核心能耐,能有著更深入的瞭解。 本研究發現成功企業於自創品牌之歷程中,共同存在著某些影響因素,有心自創品牌之企業可參照下述要項進行衡量: 一、分析產業之特性並隨時衡量企業所處產業價值鏈之位置 二、描繪自身產業網路進而分析自身事業網路之優劣 三、與產業內關鍵事業夥伴結盟與合作,建構專屬核心資源 四、積極延伸企業價值活動組合之服務,如往上游研發設計或下游行銷通路 五、衡量企業代工產品於市場上競爭強度如何,例如藉由在指標性市場之銷售量分析 / The goal of this research is to study how corporations in Taiwan transform original equipment manufacturer (OEM) / original design manufacturer (ODM) into the development of their own brands. In this thesis, the research approach is to analyze and discuss successful cases in different industry sectors and evaluate the critical factors that contribute to the successes. The results can serve as a strategic guideline for companies that are seeking to develop new and innovative brands. In this research, qualitative approaches are applied to case examinations through secondary data analysis and case interviews. There are two companies in the case study: Franz and hTC. The results are organized into four categories corresponding to four major contributing factors for brand value development. These factors include industry environment, business scope, relationship network, and core resources. Through the analysis of these four categories, the logistics for success in brand development can be well understood. During the study, it is shown that there are common points which influence whether the corporations can overcome challenges involved in brand development. The intended managers can refer to the following points as guidelines: 1.Analyze the industry trait and evaluate the company’s positioning in the value chain constantly. 2.Describe its own industry network and analyze the strengths and weaknesses 3.Develop strategy alliances and cooperate with key players in the industry; build and acquire specific core resources 4.Progressively make decisions based on successes from other companies such as backward integration toward research& development, or forward integration toward marketing distribution 5.Evaluate the competitive strength of the contract manufacturing products on the market by analyzing the sales figures of the key-index markets.
49

Real-time previsualization on set / Real-tids previsualisering vid filminspelning

Strömgren, Aron January 2017 (has links)
The execution of this thesis was based on one primare question and threesecondary questions: Primary question at issue: Is it possible to develop a system to previsualize computer generatedgraphics in real-time on a film set with available equipment on theuniversity? Secondary questions at issue: Is it possible to sync the camera feed with the motions of the HTC Vive to getan acceptable result in the game engine with existing equipment? Will the result be able to be integrated with the Computer Graphicsprogramme at LTU? How much access to control and manipulate the previsualized computergenerated graphics, while filming can be achieved? The purpose of this report is to try a method with the available equipment, toproduce a prototype of a tool to previsualize computer generated graphics inreal-time. The equipment used for the method was a computer, web camera, HTC Vive anda green screen. All the equipment was linked together with the game engineUnity. This resulted in a prototype of a tool that in real-time can mimic themotions of the camera, replace colored background and has the feature of realtimescene editing, as the previsualization runs. / Utförandet av detta examensarbete baserades på en primär frågeställning, samttre ytterligare sekundära frågor: Primär frågeställning: Kan man med hjälp av befintlig utrustning på universitetet ta fram enmodell för att previsualisera datorgenererad grafik i real-tid vid en inspelning? Sekundära frågeställningar: Kommer det gå att synka bild från webcamera med fångade rörelser frånHTC Vive och få ett godtagbart resultat från spelmotorn med befintligutrustning? Kan man använda resultatet som ett verktyg för utbildningen Datorgrafikpå LTU? Hur mycket kontroll för den förhandsvisade grafiken går att uppnå i realtid? Syftet med rapporten är att framställa och bepröva en prototyp av en produkt föratt kunna förhandsvisa datorgenererad grafik i real-tid, med befintlig utrustning. Metoden utövades med en dator, web kamera, HTC Vive och en green screen.Genom att använda spelmotorn Unity knöts utrustningen samman för attresultera i en prototyp som i real-tid fångar kamerans rörelser, ersätter färgadbakgrund och kan manipuleras direkt vid inspelning.
50

Croissance de films de cuprates supraconducteurs par épitaxie par jets moléculaires

Beuran, Florin 11 February 2005 (has links) (PDF)
Ce travail concerne l'épitaxie par jets moléculaires de films de BiSrCaCuO. On y présente un dispositif de pilotage de la croissance grâce à la diffraction d'électrons rapides RHEED, comprenant également des logiciels d'analyse permettant de corréler l'évolution du diagramme RHEED, avec les propriétés physiques (composition, structure et morphologie, transport ...). Cette analyse, appliquée au cas de films appauvris en Bi, permet de les décrire comme une nanostructure d'intercroissance, en partie ordonnée suivant un modèle " mur de briques " où deux types de nanophases alternent en quinconce : Bi-2212 et Bi-2PRQ d'épaisseur double. Selon la composition moyenne des films, trois familles de nanophases 2PRQ sont identifiées, qui correspondent à des modèles structuraux spécifiques : stoechiométriques Bi-2267, riches en Sr Bi-2446, riches en Cu Bi-2429 comportant des plans Cu2O3 de type échelles. Les conditions physiques pour la synthèse de chaque famille nanostructurée sont décrites.

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