Recent hand tracking systems have contributed to enhancing user experience in the virtual environment (VE) due to its natural and intuitive interaction. In addition, wearable haptic devices are another approach to provide engaging and immersive experiences. However, controllers are still prevalent in VR (Virtual Reality) games as a main interaction device. Also, haptic devices are rare and not widely accepted by users because they get bulky to implement sophisticated haptic sensation. To overcome this issue, I conducted experiments (Study 1 and Study 2 of this Thesis) to investigate the effect of interaction method (controller and whole-hand interaction using hand tracking) and vibrotactile feedback on user experience in the VR game. In Study 1 of this Thesis, I recruited 36 participants and compared the user's sense of presence, engagement, usability, and task performance under three different conditions: (1) VR controllers, (2) hand tracking without vibrotactile feedback, and (3) hand tracking with vibrotactile feedback at fingertips through the gloves I developed. The gloves deliver vibrotactile feedback at each fingertip by vibration motors. I observed that whole-hand interaction using hand tracking enhanced the user's sense of presence, engagement, usability, and task performance. Further vibrotactile feedback increased the presence and engagement more clearly. Based on the participants' feedback, I could further modify the form factor to make it more usable in the VR game and comfortable to wear on a regular basis. In this sense, in Study 2 of this Thesis, I developed a new thimble-shape device to deliver vibrotactile feedback only at one fingertip rather than ten fingertips. Further, social VR is an emerging VR platform where multiple users can interact with one another. However, most social VR applications have not provided a sense of touch. I recruited 24 participants and conducted an experiment that explored the effects of interaction method and fingertip vibrotactile feedback on the user's sense of social presence, presence, engagement, and task performance in a cooperative VR game under four different conditions: (1) VR controllers without vibrotactile feedback, (2) VR controllers with vibrotactile feedback, (3) hand tracking without vibrotactile feedback, and (4) hand tracking with vibrotactile feedback with the fingertip vibrotactile device. The results showed that whole-hand interaction using hand tracking increased the level of presence. In addition, multiple items in the presence questionnaire indicated that vibrotactile feedback enhanced the level of presence as well. However, I could not observe the significant difference in social presence due to the unique setting of this experiment. Unlike the previous studies, my task was sufficiently cooperative, and thus, the participants felt high level of social presence regardless the conditions, which led to the ceiling effect. I also observed that there was no significant difference in engagement. Controller conditions had higher performance than hand tracking due to the technological limitations in hand tracking. Results are discussed in terms of implications for the components of interaction in the VR with hands, a touch in social VR, cooperative VR game, and practical design guidelines. / Master of Science / Recent hand tracking systems have contributed to enhancing user experience in the virtual environment (VE) due to its natural and intuitive interaction. In addition, wearable haptic devices are another approach to provide engaging and immersive experiences. However, controllers are still prevalent in VR (Virtual Reality) games as a main interaction device. Also, haptic devices are rare and not widely accepted by users because they get bulky to implement sophisticated haptic sensation. To overcome this issue, I conducted experiments (Study 1 and Study 2 of this Thesis) to investigate the effect of interaction method (controller and whole-hand interaction using hand tracking) and vibrotactile feedback on user experience in the VR game. In Study 1 of this Thesis, I recruited 36 participants and compared the user's sense of presence, engagement, usability, and task performance under three different conditions: (1) VR controllers, (2) hand tracking without vibrotactile feedback, and (3) hand tracking with vibrotactile feedback at fingertips through the gloves I developed. The gloves deliver vibrotactile feedback at each fingertip by vibration motors. I observed that whole-hand interaction using hand tracking enhanced the user's sense of presence, engagement, usability, and task performance. Further vibrotactile feedback increased the presence and engagement more clearly. Based on the participants' feedback, I could further modify the form factor to make it more usable in the VR game and comfortable to wear on a regular basis. In this sense, in Study 2 of this Thesis, I developed a new thimble-shape device to deliver vibrotactile feedback only at one fingertip rather than ten fingertips. Further, social VR is an emerging VR platform where multiple users can interact with one another. However, most social VR applications have not provided a sense of touch. I recruited 24 participants and conducted an experiment that explored the effects of interaction method and fingertip vibrotactile feedback on the user's sense of social presence, presence, engagement, and task performance in a cooperative VR game under four different conditions: (1) VR controllers without vibrotactile feedback, (2) VR controllers with vibrotactile feedback, (3) hand tracking without vibrotactile feedback, and (4) hand tracking with vibrotactile feedback with the fingertip vibrotactile device. The results showed that whole-hand interaction using hand tracking increased the level of presence. In addition, multiple items in the presence questionnaire indicated that vibrotactile feedback enhanced the level of presence as well. However, I could not observe the significant difference in social presence due to the unique setting of this experiment. Unlike the previous studies, my task was sufficiently cooperative, and thus, the participants felt high level of social presence regardless the conditions, which led to the ceiling effect. I also observed that there was no significant difference in engagement. Controller conditions had higher performance than hand tracking due to the technological limitations in hand tracking. Results are discussed in terms of implications for the components of interaction in the VR with hands, a touch in social VR, cooperative VR game, and practical design guidelines.

A viscous/inviscid interaction method for predicting the effect of viscosity on the performance of wetted and cavitating propulsors is presented. The emphasis is placed on steady wetted and cavitating propulsor flows. A three-dimensional low order potential based boundary element method is strongly coupled with a two dimensional integral boundary layer analysis method based on the strip theory assumption. The influence of viscosity on the outer inviscid flow is modeled through the wall transpiration model by distributing “blowing” sources on the propulsor blade and trailing wake surfaces. The boundary layer edge velocities are expressed as the sum of the inviscid edge velocity and a correction which depends only on the boundary layer variables. The influence of outer potential flow on the inner boundary layer flow is considered through the edge velocities. In the case of sheet cavitation, a “thin” cavity approach is employed and the viscous/inviscid interaction method is applied on the blade surface underneath the cavity. On the cavity surface, the friction force coefficient is forced to be zero. Numerical predictions by the present viscous/inviscid interaction method are presented for open, ducted, and water-jet propulsors. For water-jet propulsors, the flow is solved in an iterative manner by solving the rotor and stator problems separately and by considering the time-averaged effects of one component on the other. Predicted forces, pressure distributions, and boundary layer variables are compared with those predicted by other numerical methods and experimental measurements. / text

För att undersöka interbedömarreliabiliteten i Emotional Interaction Style – assessment (EIS – assessment), vid bedömningar av Marschak Interaction Method (MIM), har tre inspelade MIM filmer skattats av sju bedömare. Reliabiliteten beräknades med intraklasskorrelationskoefficient (ICC). I bakgrunden har en teoretisk genomgång gjorts av aktuell forskning gällande barns utveckling och samspel mellan barn och föräldrar. Vidare har bakgrunden till MIM och EIS-assessment redovisats. För att ytterligare belysa användbarheten av skalan har bedömarna, i samband med skattningen av filmerna, reflekterat och förutsättningslöst skrivit ned tankegångar, frågor och erfarenheter vilka varit en del av diskussionerna i samband med att uppsatsgruppen träffats. Medelvärdet på intraklasskorrelationskoefficienten, på hela materialet, visar på en god samstämmighet mellan skattarna. Styrkan i överensstämmelsen i film A värderas som god, i film B mycket god och i film C hyfsad. I film A och B värderas den inre konsistensen (Cronbachs alfa) som mycket god. I film C värderas den inre konsistensen som god. Vår bedömning är att EIS – assessment är en användbar skala för att beskriva samspel mellan föräldrar och barn i kliniska sammanhang och att det vore värdefullt med fortsatt forskning.

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ABSTRACT EFFECT OF INITIAL SUPPORT OF EXCAVATION ON SEISMIC PERFORMANCE OF CUT AND COVER STRUCTURES Rezaei, Hamidreza M.Sc., Department of Civil Engineering Supervisor: Asst. Prof. Dr. Alp Caner MAY 2011, 66 pages The effect of the initial support and its embedment depth, on the seismic performance of cut and cover tunnels is investigated. Cut and cover construction is one of the fastest and cheapest methods for constructing rectangular shallow tunnels. Construction of cut and cover structure in soil usually starts with installation of the initial support of excavation system, which may consists of rigid type of initial supports such as tangent piles or secant piles. These systems usually remain in place after completion of the final structure. However, to simplify the design, it is a common practice to ignore the contribution of initial support. In this study the effect of initial support of excavation on the seismic performance of cut and cover tunnels is investigated by means of a detailed dynamic finite element analysis. Three different tunnel geometries, three soil types and three acceleration histories were considered Results of the study show that depending on the soil stiffness (soft, medium, or stiff soil), the dynamic response of the tunnel deformations are affected significantly by the initial support of excavation. The effect of the initial support diminishes as the quality of the soil improves. Therefore, dynamic analyses are recommended for the final design of this type of structures especially in soft soils.

Made available in DSpace on 2015-04-11T14:02:54Z (GMT). No. of bitstreams: 1 Mauro Ricardo da Silva Teofilo.pdf: 1416910 bytes, checksum: d4f41b9f784e48975a66441e08b837f1 (MD5) Previous issue date: 2007-09-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / With the intense use of applicative in mobile device, the question usability begins to invigorate strongly as a study object, it is being considered a determinant factor of the success of this segment of the mobile computation. This work proposes an improvement way in the usability of the embedded applicative in mobile devices, considering a new method of user interaction. The Mandos interaction method is based on task idea, which consists in a possible operation that could be executed in an applicative by the user and probabilities between task changes. The cited probabilities will be used for construction of the user interface to interact dynamically with the user. To validate the considered method was developed a framework, called Mandos, which propitiates functionalities to the applicative developer that uses Java technology. A case study will be presented where some prototypes of embedded applicative mobile was developed, using Mandos framework for the interaction method evaluation. The evaluation was established in order to identify any relation of usability gain or loss of applicatives, having like approvers the own users of the embedded applicative in mobile telephones. / Com o uso intenso de aplicativos em aparelho celulares a questão da usabilidade passa a vigorar fortemente como objeto de estudo, sendo considerado um fator determinante do sucesso deste segmento da computação móvel. Este trabalho propõe uma forma de aprimoramento da usabilidade dos aplicativos embarcados em aparelhos celulares, formulando um novo método de interação com o usuário. O método de interação Mandos foi baseado na idéia de tarefas, que consiste em uma operação de uma função de um aplicativo a ser executada pelo usuário, e nas probabilidades de transição entre tarefas. As probabilidades de transição entre tarefas serão utilizadas para construção da interface com o usuário, e tais probabilidades são alteradas no decorrer do uso do aplicativo, fazendo com que a interação seja dinâmica. Para validar o método proposto foi desenvolvido um framework, chamado de Mandos, que adiciona algumas funcionalidades já prontas para o desenvolvedor de aplicativos que utiliza a tecnologia Java. Será apresentado um estudo de caso onde alguns protótipos de aplicativos embarcados em telefone móveis foram desenvolvidos, usando o framework Mandos, para a avaliação do método de interação. A avaliação foi baseada de modo a identificar qualquer relação de ganho ou perda de usabilidade dos aplicativos, tendo com avaliador os próprios usuários dos aplicativos embarcados em telefones móveis.