智慧型手機時代來臨後，華人手機品牌廠有如雨後春筍般的冒出。本篇論文以小米、華為、宏達電作為個案研究對象，研究目的在於了解三間個案企業是如何在競爭激烈的全球市場中生存下來。關於研究發現，詳述如下： 小米是一家軟體導向的企業，採用互聯網行銷的方式，將銷售對象集中在網路顧客群，避開了屬於一級戰場的實體通路。最初在網路上建立口碑，待產品推出後，運用高性價比的特點吸引顧客，接著採用「饑渴行銷」的策略，以限量的方式去刺激顧客的購買欲望。然而，小米不靠販賣硬體獲利，主要的收入來源在於內容服務、應用程式、遊戲。 華為是一家硬體導向的企業，以販賣電信設備為主要經營業務。2009年進入到智慧型手機業務後，以「機海戰術」為領導方針，在不同價格區間都可以看到華為品牌的手機款式。2013年，施展雙品牌策略，「華為」和「榮耀」分家，主打高階手機P系列、D系列、Mate系列為華為品牌；主打中低階及網路市場為榮耀品牌。此外，華為旗下子公司海思擁有晶片自製技術，垂直整合能力在未來將會是華為角逐通訊市場的最大優勢。 宏達電是一家硬體導向的企業，屬於早期投入到智慧型手機業務的華人品牌廠，在歐美國家中具有一定的知名度。2011年曾經高居全球前五大智慧型手機品牌，競爭優勢在於工業設計及軟硬體整合，不管是手機的立體音效、鏡頭、金屬機殼都有自己的風格。雖然，在2012年第四季退出全球前十大智慧型手機品牌廠，但卻是台灣少數能夠走出國際的品牌大廠之一。 三間個案公司的競爭策略及商業模式各不相同，但卻讓世界看到了華人不是只有代工，也有能力在品牌和市場行銷做出令人印象深刻的成績。

Virtual Reality consumer hardware is now available for the masses through the HTC Vive, Oculus Rift and PlayStation VR. Locomotion or virtual travel inside immersive experiences is an area which is yet to be fully solved due to space constraints, problems with retaining immersion and potential sickness. This thesis had the goal of evaluating user preferences for four locomotion methods in Virtual Reality with a first generation HTC Vive through the gaming platform Steam.  The theoretical framework provides an elementary understanding of the field of Virtual Reality and how humans interact and get affected by locomotion in that context. To contextualize the experience of evaluating the locomotion systems the Hedonic-Motivation System Adoption Model is used as it covers intrinsic motivation which is common in video games, social networking and virtual worlds.  An extensive process for games selection has been performed which has resulted in four locomotion methods with four games per method. Sixteen participants got to test one locomotion method each where their gameplay got recorded for later observation. After each game session answers were provided by the participants based on surveys and after completion of all games a questionnaire gauged their sickness level.  The conclusion proved inconclusive. While the results without interpretation showed the locomotion method Artificial as the overall winner a range of potential problems were found with the study in general. Some problems included observations which did not provide the expected results, introducing doubt into either how the study was conducted or the reliability of certain users. A larger sampler size along with a better study procedure could possibly have provided a more conclusive answer.

The goal of this thesis is to learn about virtual reality and the aspects of the development for this platform. The next goal is to find well suited development environment for the application and test the capabilities and limits of them both. The thesis will be completed by designing, implementing and then testing the aplication using knowledge learnt.

Mitt examensarbete är genomfört som en undersökande designprocess, vars syfte är att undersöka vilka krav en VR-upplevelse, med hög immersion, ställer på den fysiska miljön för att sedan omsätta dessa krav i ett färdigt koncept av ett fysiskt rum som ska fungera självgående. Med det fysiska rummet syftar jag till det verkliga rummet i vilket det virtuella rummet finns tillgängligt att uppleva via VR-utrustning. Det fysiska rummet är i detta fall också platsspecifikt då jag har jobbat med beställarna Länsmuseet Gävleborg samt Region Gävleborg, men konceptet går att anpassa till andra miljöer, utefter kraven som dessa ställer.  Detta rum kommer främst att användas för visning av olika världsarv i VR, och världsarvet som inviger rummet är Hälsingegården Bortom Åa, även kallad Fågelsjö Gammelgård. Det virtuella innehållet har delvis påverkat rummets utformning, främst i valen av grafisk utsmyckning.  Designprocessen har bestått av ett kontinuerligt researcharbete, problemanalys, användarobservationer, idégenerering som innefattar workshop, deltagarobservationer, prototypbygge, konceptutveckling och sammanställande samt visualiserande av färdigt koncept.  Jag har under processen arbetat med det fysiska rummet i dessa fem problemområden: planlösning, säkerhet, inbjudande och inkluderande, utrustning samt instruerande. Något som har präglat min process mycket är kravet om att rummet ska fungera självgående, det vill säga att ingen extra instruktör eller övervakare ska behövas för användning av rummet. Detta är ett krav från Länsmuseet Gävleborg och är av ekonomiska och praktiska skäl. En viktig poäng med mitt arbete har varit att tillgängliggöra kulturella upplevelser för de som inte har möjlighet att ta sig till den verkliga platsen. Av den anledningen har jag jobbat mot att rummet bör vara tillgängligt för så många som möjligt. Genom att presentera ett världsarv via en modern och spännande teknik kan det bidra till ökat intresse av historia och kultur bland unga samt generera fler besökare till museet och i förlängningen ekonomiskt gynna kulturutvecklingen i Gävle. Det kan även minska klimatpåverkan genom att resor till platser långt bort inte behöver genomföras, så som studiebesök.  Mitt examensarbete har resulterat i ett innovativt koncept av ett rum tillägnat offentliga utställningar i VR, med vissa plats- och situationsspecifika detaljer, så som storlek och val av vissa grafiska detaljer. Det fysiska rummet består i sin helhet av två mindre delrum. I de rummen finns både rent tekniska, visuella och sensoriska lösningar som behandlar de olika problemområdena.  Detta rum har presenterats med renderingar, illustrationer samt skalmodell. I skrivande stund har konceptet i sin helhet redan förverkligats på Länsmuseet Gävleborg och finns där att besöka, men det jag presenterar i denna uppsats är arbetet som ledde fram till konceptet.

The objective of this research was to investigate the performance of two-phase spray cooling with HFC-134a and HFO-1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next-generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal management of high heat flux power electronics (i.e., IGBTs) in electric-drive vehicles. Potential benefits of two-phase spray cooling include achieving more efficient and reliable operation, as well as compact and lightweight system design that would lead to cost reduction. The experimental work involved testing of four different enhanced boiling surfaces in comparison to a plain reference surface, using a commercial pressure-atomizing spray nozzle at a range of liquid flow rates for each refrigerant to determine the spray cooling performance with respect to heat transfer coefficient (HTC) and critical heat flux (CHF). The heater surfaces were prepared using dual-stage electroplating, brush coating, sanding, and particle blasting, all featuring "practical" room temperature processes that do not require specialized equipment. Based on the obtained results, HFC-134a provided a better heat transfer performance through higher HTC and CHF values compared to HFO-1234yf at all tested surfaces and flow rates. While majority of the tested surfaces provided comparable HTC and modestly higher CHF values compared to the reference surface, one of the enhanced surfaces offered significant heat transfer enhancement.

Virtuální realita je v současné době využívána nejen pro zábavu, ale i pro práci a sociální interakci, kde má soukromí a důvěrnost informací vysokou prioritu. Avšak bohužel, bezpečnostní opatření uplatňovaná dodavateli softwaru často nejsou dostačující. Tato práce přináší rozsáhlou bezpečnostní analýzu populární aplikace Bigscreen pro virtuální realitu, která má více než 500 000 uživatelů. Byly využity techniky analýzy síťového provozu, penetračního testování, reverzního inženýrství a dokonce i metody pro application crippling. Výzkum vedl k odhalení kritických zranitelností, které přímo narušovaly soukromí uživatelů a umožnily útočníkovi plně převzít kontrolu nad počítačem oběti. Nalezené bezpečnostní chyby umožnily distribuci škodlivého softwaru a vytvoření botnetu pomocí počítačového červa šířícího se ve virtuálních prostředích. Byl vytvořen nový kybernetický útok ve virtální realitě nazvaný Man-in-the-Room. Dále byla objevena bezpečnostní chyba v Unity engine. Zodpovědné nahlášení objevených chyb pomohlo zmírnit rizika pro více než půl milionu uživatelů aplikace Bigscreen a uživatele všech dotčených aplikací v Unity po celém světě.

this thesis complex inverse heat transfer problem, which is focused on optimal design of experiment, is studied. There are many fields and applications in technical practice, where inverse tasks are or can be applied. On first place main attention is focused on industrial metallurgical processes such as cooling of continues casting, hydraulic descaling or hot rolling. Inverse problems are in general used to calculate boundary conditions of differential equations and in this field are used to find out Heat Transfer Coefficient (HTC). Knowledge of numerical approximation of precise boundary conditions is nowadays essential. It allows for example design of optimized hot rolling mill cooling focused on material properties and final product quality. Sequential Beck’s approach and optimization method is used in this work to solve inverse heat transfer problems. Special experimental test bench measuring heat transfer intensity was developed and built to full fill specific requirements and required accuracy. There were four different types of thermal sensor applied and studied. Those sensors are in usage in Heat Transfer and Fluid Flow laboratory (Heatlab) at various experimental test benches. Each specific sensor was tailored in Heat Transfer and Fluid Flow Laboratory to specific metallurgical application. Fist type of sensor was designed to simulate cooling during continuous casting. Second sensor is used for experiments simulate hot rolling mill cooling, while third sensor is designated for experiments with fast moving hot rolled products. Last sensor is similar to sensor type one, but thermocouple is located parallel to cooled surface. Experimental part of this study covers series of measurements to investigate Heat Transfer Coefficient (HTC) for various types of coolant, cooling mixtures and spray parameters. Results discovered in this study were compared with published scientific articles, and widely extend the knowledge of cooling efficiency for commonly used

Ce travail rend compte du développement de substrats à texture biaxiale pour les supraconducteurs à hautes températures critiques de seconde génération dit "coated conductor". Le substrat a été obtenu par un procédé de laminage recuit. Les matériaux utilisés sont des alliages industriels Cu55Ni44Mn (Constantan) et le Cu70Ni30. Comparativement au NiW généralement utilisé, ces cupronickels sont non magnétiques à 77 K et permettent donc des applications en courant alternatif ; ils sont en outre moins onéreux.<br />Des essais sur des laminoirs différents, avec ou sans lubrification et en modifiant le taux d'écrouissage ont permis de mettre en évidence des effets de peau et d'optimiser le procédé de déformation.<br />Les températures de recuit ont été choisies à la suite de caractérisations de texture avant et après le recuit ainsi que de mesures in-situ par diffraction de rayons X durs durant la montée en température.<br />Des laminages supérieurs à 98% et des recuits entre 900°C et 950°C en atmosphère protectrice ont permis d'obtenir des rubans ayant une forte texture cubique : désorientations hors du plan (DT) de 5° et dans le plan de 8°. Une partie de la surface est cependant maclée (entre 8% et 10%). Celle-ci entraîne localement de fortes désorientations.<br />L'état de surface a été contrôlé et amélioré par l'utilisation de rouleaux polis miroirs, l'optimisation des conditions de recuit (atmosphère et durée du palier) ainsi que l'ajout d'une étape d'électropolissage.<br />Des essais mécaniques et magnétiques ainsi qu'une étude d'oxydation ont été pratiqués pour vérifier le comportement du ruban dans les conditions d'utilisation comme dans les conditions rencontrées pendant les différents étapes de la réalisation du câble.<br />Le dépôt d'une couche d'oxyde protectrice LZO, sur le substrat a été réalisé avec succès. Les conditions d'un prétraitement sous atmosphère sulfurée, nécessaire à une bonne épitaxie de la couche, ont été déterminées : 1 h à 600°C avec un flux à 0,2 ppm d'H2S.<br />Enfin des essais sur le développement d'un alliage à barrière de diffusion in situ Cu Ni Y permettant de s'affranchir de la première couche tampon ont été menés.

The high turbine inlet temperature of modern gas turbines poses a challenge to the material used in the turbine blading of the primary stages. Mechanical failure mechanisms are more pronounced at these high temperatures, setting the lifetime of the blade. It is therefore crucial to obtain accurate local metal temperature predictions of the turbine blade. Accurately predicting the external heat transfer coefficient (HTC) distribution of the blade is therefore of uttermost importance. At present time, Siemens Energy uses the boundary layer code TEXSTAN for this purpose. The limitations coupled to such codes however make them less applicable for the complex flow physics involved in the hot gas path of turbine blading. The thesis therefore aims at introducing CFD for calculating the external HTC. This includes conducting an extensive literature study to find and validate a suitable methodology. The literature study was centered around RANS modeling, reviewing how the calculation of the HTC has evolved and the performance of some common turbulence and transition models. From the literature study, the SST k − ω model in conjunction with the γ − Reθ transition model, the v2 − f model and the Lag EB k − ε model were chosen for the investigation of a suitable methodology. The validation of the methodology was based on the extensively studied LS89 vane linear cascade of the von Karman Institute. In total 13 test cases of the cascade were chosen to represent a wide range of flow conditions. Both a periodic model and a model of the entire LS89 cascade were tested but there were great uncertainties whether or not the correct flow conditions were achieved with the model of the entire cascade. It was therefore abandoned and a periodic model was used instead. The decay of turbulence intensity is not known in the LS89 cascade. This made the case difficult to model since the turbulence boundary conditions then were incomplete. Two approaches were attempted to handle this deficiency, where one was ultimately found invalid. It was recognized that the Steelant-Dick postulation could be used in order to find a turbulent length scale which when specified at the inlet, lead to fairly good agreement with data of the HTC. The validation showed that the SST γ − Reθ model performs relatively well on the suction side and in transition onset predictions but worse on the pressure side for certain flow conditions. The v2 − f model performed better on the pressure side and on a small portion of the suction side. Literature emphasized the importance of obtaining proper turbulence characteristics around the vane for accurate HTC-predictions. It was found that the results of the validation step could be closely coupled to this statement and that further work is needed regarding this. Further research must also be done on the Steelant-Dick postulation to validate it as a reliable method in prescribing the inlet length scale.

This thesis deals with the concept of virtual reality, its history, present-day possibilities and available devices and technologies for virtual reality and ways of creating assets such as models, textures and animations for virtual reality applications. The practical part of this work deals with design and creation of three-dimensional models, textures, animations and environment for use in interactive application in virtual reality and also with design and creation of such application to demonstrate their use.