Arthroscopic knee surgery can be challenging because there is no intuitive relationship between the arthroscopic image, shown on a screen above the patient, and the camera in the surgeon's hand. As a result, arthroscopic surgeons require extensive training and experience. This thesis describes a computer system to help improve target acquisition in arthroscopy by visualizing the location and alignment of an arthroscope using augmented virtuality. A 3D computer model of the patient's joint (from CT) is shown, along with a model of the tracked arthroscopic probe and the projection of the camera image onto the virtual joint. We performed a user study to determine the effectiveness of this navigated display; the study showed that for novice residents, the navigated display improved target acquisition. However, residents with at least two years of experience performed worse. For surgeons, no effect on performance was found. / Thesis (Master, Computing) -- Queen's University, 2010-11-25 23:29:46.526

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第20738号 / 情博第652号 / 新制||情||112(附属図書館) / 京都大学大学院情報学研究科社会情報学専攻 / (主査)教授 黒田 知宏, 教授 大手 信人, 教授 松田 哲也 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

This thesis addresses the subject of converging real and virtual environments to a combined entity that can facilitate physiologically complying interfaces for the purpose of training. Based on the mobility and physiological demands of dismounted soldiers, the base assumption is that greater immersion means better learning and potentially higher training transfer. As the user can interface with the system in a natural way, more focus and energy can be used for training rather than for control itself. Identified requirements on a simulator relating to physical and psychological user aspects are support for unobtrusive and wireless use, high field of view, high performance tracking, use of authentic tools, ability to see other trainees, unrestricted movement and physical feedback. Using only commercially available systems would be prohibitively expensive whilst not providing a solution that would be fully optimized for the target group for this simulator. For this reason, most of the systems that compose the simulator are custom made to facilitate physiological human aspects as well as to bring down costs. With the use of chroma keying, a cylindrical simulator room and parallax corrected high field of view video see-though head mounted displays, the real and virtual reality are mixed. This facilitates use of real tool as well as layering and manipulation of real and virtual objects. Furthermore, a novel omnidirectional floor and thereto interface scheme is developed to allow limitless physical walking to be used for virtual translation. A physically confined real space is thereby transformed into an infinite converged environment. The omnidirectional floor regulation algorithm can also provide physical feedback through adjustment of the velocity in order to synchronize virtual obstacles with the surrounding simulator walls. As an alternative simulator target use, an omnidirectional robotic platform has been developed that can match the user movements. This can be utilized to increase situation awareness in telepresence applications.

This thesis explores the use of virtual reality as a prototyping tool for designpractitioners to utilize when designing artifacts situated in physical places.Methods used in the study are qualitative and derive from the field ofinteraction design. The topic is explored through literature review on theattributes of virtual reality and sense of place, presented in the theorychapter, and is connected to the empirical research throughout the designprocess chapter. The theories presented strongly indicate that places affecthuman behavior, making them a substantial part of the user experience wheninteracting with designed artifacts in specific locations, which is echoedthough the target audience who voice the need to prototype design conceptsin the context of place. The study culminates in two kinds of virtual realityprototypes, dubbed contextual prototypes, that are suggested to havedifferent use cases depending on what the purpose for prototyping is.

<p dir="ltr">Construction workers often suffer from excessive stress from working in dynamic and complex hazard-rich environments. These workers are subject to experiencing diverse external stressors, which can increase their involvement in risk-taking behaviors by increasing human error, referring to individuals’ misperceptions and misjudgment. Task, social, and environmental stressors are the most common external stressors that can negatively impact workers’ safety performance. Task stressors mainly occur when the projects fall behind schedule which puts workers under productivity and mental demand. In addition, workers are exposed to social stressors due to the inherently social environment of construction job sites requiring collaborative efforts. Such workers also suffer from environmental stressors as they mainly need to perform construction tasks outdoors in extreme environments. There is a paucity of research to empirically examine how such external stressors may affect workers’ situational awareness and risk-taking behaviors. Therefore, the overall goal of this dissertation is to <i>examine the theoretical foundations and empirical evidence of changes in workers’ decision dynamic in the construction industry when exposed to task (e.g., productivity pressure and mental demand), social (e.g., peer pressure), and environmental (e.g., heat stress) stressors.</i></p><p dir="ltr">To accomplish this, a series of studies were conducted to investigate the effects of task, social, and environmental stressors on workers’ situational awareness and hazard identification skills. To do so, taking advantage of novel technologies, this study developed immersive mixed reality (MR) and augmented virtuality (AV) simulating high-risk construction tasks. Such environments were integrated with several wearable sensing technologies to measure individuals’ cognitive responses and decision dynamics while completing the tasks under different stressors. The findings demonstrated that external stressors reduce worker situational awareness, impair their cognitive processes, and negatively affect their safety performance.</p><p dir="ltr">Such findings were then utilized to develop an intelligent and comprehensive AI-based predictive system to identify at-risk workers imposed to external stressors. This system translates physiological, cognitive, and biomechanical metrics into AI-identified predictors of three types of external stressors; localizes workers, and assesses risks of being injured in real-time which will then dictate the urgency of providing any intervention. These analyses are then used to identify and propose tailored safety interventions.</p><p dir="ltr">This dissertation contributes to the existing body of knowledge by adopting innovative approaches to empirically study the extent to which external stressors may affect workers’ decision dynamics by examining the changes in their situational awareness, risk-taking, and safety performance measures. In addition, this work contributes to practice by raising awareness about the adverse effects of several cognitive biases due to such stressors, such as risk compensation, cognitive tunneling, and impaired attentional distribution, which can undermine the efficacy of safety interventions in the construction industry. It highlights the critical role of these cognitive biases in safety practices and the necessity of educating safety professionals and workers about how psychological factors can impact safety on the job site and potential ways to mitigate these potential negative impacts. Further, the developed AI-based predictive system breaks new ground by identifying at-risk workers, assessing potential risks, and recommending safety interventions.</p>

The thesis evaluates the current possibilities and problems of drone control and suggests possible solutions. The aim is to control drones more efficiently and easily. The final system is based on third person view and Augmented Virtuality technology where real data from the drone (video-stream, localization information) has been integrated into the virtual 3D model of the surroundings. The model of the surroundings has been created using free data. The application provides the pilot with the means to navigate in the surroundings and to navigate to destinations. It also offers the possibility to define areas with various potential security risks during mission planning, which will be used to navigate in the mission zones, and to visualize the overall situation in the virtual scene extended with online real data.

Three-dimensional literature is a virtually non-existent or in any case very rare and emergent digital art form, defined by the author as a unit of text, which is not confined to the two-dimensional layout of print literature, but instead mediated across all three axes of a virtual space. In collaboration with two artists the author explores through a bodystorming workshop how writers and readers could create and experience three-dimensional literature in mixed reality, by using mobile devices that are equipped with motion sensors, which enable users to perform embodied interactions as an integral part of the literary experience.For documenting the workshop, the author used body-mounted action cameras in order to record the point-of-view of the participants. This choice turned out to generate promising knowledge on using point-of-view footage as an integral part of the methodological approach. The author has found that by engaging creatively with such footage, the designer gains a profound understanding and vivid memory of complex design activities.As the outcome the various design activities, the author developed a concept for an app called TEXTILE. It enables users to build three-dimensional texts by positioning words in a virtual bubble of space around the user and to share them, either on an online platform or at site-specific places. A key finding of this thesis is that the creation of three-dimensional literature on a platform such as TEXTILE is not just an act of writing – it is an act of sculpture and an act of social performance.

This project is an examination of the possibility of using existing software to develop Virtual Reality (VR) software that includes key aspects of objects in a user’s surroundings into a virtual environment, producing Augmented Virtuality (AV). A defining limitation is the requirement that the software be consumer-accessible, meaning it needs run on a common smartphone with no additional equipment. Two related AV concepts were considered: shape reconstruction and positional tracking. Two categories of techniques were considered for taking the measurements of reality necessary to achieve those AV concepts using only a monocular RGB camera as sensor: monocular visual SLAM (mvSLAM) and Structure from Motion (SfM). Two lists of requirements were constructed, formalising the notions of AV and consumer-accessibility. A search process was then conducted, where existing software packages were evaluated for their suitability to be included in a piece of software fulfilling all requirements. The evaluations of SfM systems were made in combination with Multi-View Stereo (MVS) systems – a necessary complement for achieving visible shape reconstruction using a system that outputs point clouds. After thoroughly evaluating a variety of software, it was concluded that consumer-accessible AV can not currently be achieved by combining existing packages, due to several issues. While future hardware performance increases and new software implementations would solve complexity and availability issues, some inaccuracy and usability issues are inherent to the limitation of using a monocular camera. / Detta projekt är en undersökning av möjligheten att använda befintlig programvara till att utveckla Virtual Reality (VR)-programvara som infogar framstående aspekter av objekt från en användares omgivning in i en virtuell miljö och därmed skapar Augmented Virtuality (AV). En definierande begränsning är kravet på att programvaran skall vara konsumenttillgänglig, vilket innebär att den behöver kunna köras på en vanlig smartphone utan extra utrustning. Två besläktade AV-koncept beaktades: formrekonstruktion och positionsspårning. Två kategorier av tekniker togs i beaktande, vilka kunde användas för att göra de uppmätningar av verkligheten som var nödvändiga för att uppnå de tänkta AV-koncepten med hjälp av endast en monokulär RGB-kamera som sensor: monocular visual SLAM (mvSLAM) och Structure from Motion (SfM). Två listor med kriterier konstruerades, vilka formaliserade begreppen AV och konsumenttillgänglighet. En sökprocess utfördes sedan, där befintliga programvarupaket utvärderades för sin lämplighet att inkluderas i en programvara som uppfyllde alla kriterier. Utvärderingarna av SfM-system gjordes i kombination med Multi-View Stereo (MVS)-system – ett nödvändigt komplement för att uppnå synlig formrekonstruktion med ett system vars utdata är punktmoln. Efter att noggrant ha utvärderat en mängd programvara var slutsatsen att konsumenttillgänglig AV inte för närvarande kan uppnås genom att kombinera befintliga programvarupaket, på grund av ett antal olika problem. Medan framtida prestandaökningar hos maskinvara och nya programvarutillämpningar skulle lösa problem med komplexitet och tillgänglighet, är vissa problem med tillförlitlighet och användbarhet inneboende hos begränsningen till att använda en monokulär kamera.