This thesis presents the design of a tactile device that can be used to display varying magnitudes of roughness. The device is designed to be attached to an existing force feedback device in order to create a package that is able to display both macro-level (force feedback) and micro-level (tactile feedback) information to the users. This device allows the users to feel a simulated texture by placing an index finger on an aperture. The stimulus is created with a spiral brush made of nylon bristles. The brush is attached to a DC motor and the speed and direction of rotation of the brush are used to generate textures at the fingertip through the aperture. Three psychophysical experiments are conducted to study the effects of speed and direction on the roughness perception. The first experiment is designed to investigate the sensitivity to a change in the speed of the brush. This experiment is conducted for two levels of base speed and it is found that as the base speed increases, the just noticeable difference (JND) with respect to speed decreases. In the second experiment, it is found that this tactile device is able to represent textures of rough nature, such as sandpaper. It is also found that the human roughness perception cannot be described in a unique manner. Two opposite definitions of rough textures are identified in this experiment. While some users relate an increase in the speed of the brush to increasing roughness, others relate it to decreasing roughness. Further, the results show that the effects of direction are insignificant on the roughness perception for both groups of users. In the third experiment, the effects of direction are studied more closely by presenting the two directions successively with a time gap of $0.5s$. It is found that with this small time gap, the users are able to discriminate between directions, unlike in the previous experiment. The roughness perception is affected by the change in direction when the time gap is small. These findings open further areas that need to be investigated before a robust tactile device can be designed.

As a type of virtual learning community, multi-user virtual environments (MUVEs) are not only sources of entertainment but are also places where learning opportunities and community development can be created and fostered. Some multi-user virtual environments that have emerged have been designed to serve students and teachers in the K-12 sector. Although learning is a goal in these contexts, this study focused on some of the community building and social networking components. The purpose of this study was to examine whether, to what degree and how nine elementary aged students projected themselves socially through this medium. The results could provide insight into the integration of such environments into K-12 educational contexts and could serve as a launching point for further research into the learning and community aspects of MUVEs. A case study approach was used in this research study. The researcher chose a class of nine students who were enrolled in an educational MUVE as part of their regular studies. Although these students completed assignments in the MUVE, only their social interactions were analyzed. The data was collected from student communication logs in the educational MUVE Quest Atlantis and from interviews with participants. Document analysis was used to analyze transcripts of student communications in Quest Atlantis as well as transcripts from text-based interviews. The results obtained demonstrate the types of communication and tool selection patterns of elementary aged students when using text to communicate in a MUVE and provide insight that can be used by teachers to inform the integration of MUVEs in their unique learning contexts. Findings indicated that frequency of communication varied substantially between participants but message content was similar and content volume varied depending on the communication tool. Gender differences were pronounced. Results also revealed that all participants were comfortable and enjoyed their involvement in the MUVE.

It is defined in international charters that presentation is one of the main responsibilities of conservation policies. The consicousness on cultural heritages and their conservation leads to related disciplines to prepare efficient presentations. Traditional presentations cannot bear to constitute a medium where different types of information and mulitple techniques can be integrated in a single medium. This thesis considers Virtual Environment as a multi-layered medium for such a need and uses it on the presentation of a Architectural Cultural Heritage that has a very important place in the foundation of Turkish Republic. The study proposes a scheme for the process with respect to the author&amp / #8217 / s technical capabilities and literature surveys on the examples that are prepared in VE and searches the advantages or disadvantages, sufficiencies or insufficiencies. The system runs through a CD that is attached to back of the text, has an interactive virtual tour and internet pages that are all prepared by the author.

This report describes the development of an application which allows a user to program a robot in a virtual environment by the use of hand motions and gestures. The application is inspired by the use of robot lead-through programming which is an easy and hands-on approach for programming robots, but instead of performing it online which creates loss in productivity the strength from offline programming where the user operates in a virtual environment is used as well. Thus, this is a method which saves on the economy and prevents contamination of the environment. To convey hand gesture information into the application which will be implemented for RobotStudio, a Kinect sensor is used for entering the data into the virtual environment. Similar work has been performed before where, by using hand movements, a physical robot’s movement can be manipulated, but for virtual robots not so much. The results could simplify the process of programming robots and supports the work towards Human-Robot Collaboration as it allows people to interact and communicate with robots, a major focus of this work. The application was developed in the programming language C# and has two different functions that interact with each other, one for the Kinect and its tracking and the other for installing the application in RobotStudio and implementing the calculated data into the robot. The Kinect’s functionality is utilized through three simple hand gestures to jog and create targets for the robot: open, closed and “lasso”. A prototype of this application was completed which through motions allowed the user to teach a virtual robot desired tasks by moving it to different positions and saving them by doing hand gestures. The prototype could be applied to both one-armed robots as well as to a two-armed robot such as ABB’s YuMi. The robot's orientation while running was too complicated to be developed and implemented in time and became the application's main bottleneck, but remained as one of several other suggestions for further work in this project.

Η παρούσα διπλωματική εργασία ασχολείται με την κατασκευή ενός εικονικού περιβάλλοντος που αναπαριστά μια σχολική τάξη. Στην εικονική τάξη προστίθενται εικονικοί χαρακτήρες που αποτελούν τους μαθητές της τάξης καθώς επίσης και τη δασκάλα τους. Το σενάριο που ακολουθεί είναι η ενημέρωση των εικονικών μαθητών από τη διδάσκουσα για τους τρόπους αντίδρασης των μαθητών σε περίπτωση σεισμού. / -

Fixed-base driving simulators are commonplace in research and training. Simulators provide safe and controlled environments to train users on vehicle and device operation, to evaluate the safety of devices and controls, and to conduct research on driving and driving behaviours. One drawback to simulators is simulator sickness. As with motion sickness, simulator sickness can cause nausea, but additionally it has symptoms such as headache and eyestrain. Simulator sickness is a problem for multiple reasons: it can skew experimental results, it can waste participants’ and experimenter’s time, and it can limit testable populations. In addition, participants may modify their behaviour to avoid sickness, affecting experimental results or impeding learning. While sickness can reduce over multiple exposures, it is not known if any observable behaviours accompany these reductions. It is also not known why there are such marked individual differences in susceptibility. To test for behaviours that could be responsible for reducing sickness, I examined participants across two sessions in a fixed-base driving simulator. I found that gaze behaviour (eye and head movements) changed along with sickness. To determine the cause for this finding I instructed participants (pre-drive) to fixate their gaze during the curves of a simulated drive. This gaze modification was effective in reducing sickness during a first-time experience in the simulator, supporting a causal link. Next, I attempted to replace the missing vestibular input in a fixed-base simulator, so that the visual and vestibular perceptions of motion matched. This experiment showed that by providing vestibular stimulation appropriate or opposite of what would occur in the real world reduced sickness. This provided support for the theory that distracting stimulation (electrical in this case) could reduce attention to visual motion cues and therefore reduce conflict, a novel finding for simulator sickness research. Finally, I tested for any correlations between individual differences and sickness. I found that history of motion sickness and current illness both correlated with sickness, potentially useful as a pre-screening tool. In addition, driving behaviours such as speed, braking, and acceleration all correlated with sickness, showing that how a person behaves in a simulation could also contribute to sickness. / CFI, OGS, Auto21

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Computer-aided fixture planning (CAFP) is an essential part of Computer-aided design and manufacturing (CAD/CAM) integration. Proper fixture planning can dramatically reduce the manufacturing cost, the lead-time, and labor skill requirements in product manufacturing. However, fixture planning is a highly experience-based activity. Due to the extreme diversity and complexity of manufacturing workpieces and processes, there are not many fixture planning tools available for industry applications. Moreover, existing CAFP methods rarely consider integrating fixture environmental factors into fixture planning. Automatic fixture planning using VR can provide a viable way for industries. This thesis develops automated approaches to fixture planning in a virtual environment (VE). It intends to address two important issues: automatic algorithms for fixture planning, and the VE to support high fidelity evaluation of fixture planning. The system consists of three parts including fixture assembly planning, feasibility analysis of assembly tools, and motion planning for fixture loading and unloading. The virtual fixture planning system provides the fixture designer a tool for fixture planning and evaluation. Geometrical algorithms are developed to facilitate the automatic reasoning. A Web-based VE for fixture planning is implemented. The three-dimensional (3D) model visualization enables the fixture simulation and validation effectively to investigate existing problems. Approaches to construct desktop-based large VEs are also investigated. Cell segmentation methods and dynamic loading strategies are investigated to improve the rendering performance. Case studies of virtual building navigation and product assembly simulations are conducted. The developed algorithms can successfully generate the assembly plan, validate the assembly tools, and generate moving paths for fixture design and applications. The VE is intuitive and sufficient to support fixture planning, as well as other virtual design and manufacturing tasks.

In this thesis, we propose a new design of privacy and session control for improving a collaborative molecular modeling CVR system AMMP-VIS [1]. The design mainly addresses the issue of competing user interests and privacy protection coordination. Based on our investigation of AMMP-VIS, we propose a four-level access control structure for collaborative sessions and dynamic action priority specification for manipulations on shared molecular models. Our design allows a single user to participate in multiple simultaneous sessions. Moreover, a messaging system with text chatting and system broadcasting functionality is included. A 2D user interface [2] for easy command invocation is developed in Python. Two other key aspects of system implementation, the collaboration Central deployment and the 2D GUI for control are also discussed. Finally, we describe our system evaluation plan which is based on an improved cognitive walkthrough and heuristic evaluation as well as statistical usage data.

Computer-aided fixture planning (CAFP) is an essential part of Computer-aided design and manufacturing (CAD/CAM) integration. Proper fixture planning can dramatically reduce the manufacturing cost, the lead-time, and labor skill requirements in product manufacturing. However, fixture planning is a highly experience-based activity. Due to the extreme diversity and complexity of manufacturing workpieces and processes, there are not many fixture planning tools available for industry applications. Moreover, existing CAFP methods rarely consider integrating fixture environmental factors into fixture planning. Automatic fixture planning using VR can provide a viable way for industries. This thesis develops automated approaches to fixture planning in a virtual environment (VE). It intends to address two important issues: automatic algorithms for fixture planning, and the VE to support high fidelity evaluation of fixture planning. The system consists of three parts including fixture assembly planning, feasibility analysis of assembly tools, and motion planning for fixture loading and unloading. The virtual fixture planning system provides the fixture designer a tool for fixture planning and evaluation. Geometrical algorithms are developed to facilitate the automatic reasoning. A Web-based VE for fixture planning is implemented. The three-dimensional (3D) model visualization enables the fixture simulation and validation effectively to investigate existing problems. Approaches to construct desktop-based large VEs are also investigated. Cell segmentation methods and dynamic loading strategies are investigated to improve the rendering performance. Case studies of virtual building navigation and product assembly simulations are conducted. The developed algorithms can successfully generate the assembly plan, validate the assembly tools, and generate moving paths for fixture design and applications. The VE is intuitive and sufficient to support fixture planning, as well as other virtual design and manufacturing tasks.