• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 117
  • 110
  • 27
  • 6
  • 6
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 316
  • 316
  • 99
  • 95
  • 71
  • 60
  • 55
  • 49
  • 40
  • 35
  • 34
  • 33
  • 32
  • 31
  • 31
  • 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.
51

Design and Development of a Framework to Bridge the Gap Between Real and Virtual

Hossain, SK Alamgir 01 November 2011 (has links)
Several researchers have successfully developed realistic models of real world objects/ phenomena and then have simulated them in the virtual world. In this thesis, we propose the opposite: instantiating virtual world events in the real world. The interactive 3D virtual environment provides a useful, realistic 3D world that resembles objects/phenomena of a real world, but it has limited capability to communicate with the physical environment. We argue that new and intuitive 3D user interfaces, such as 3D virtual environment interfaces, may provide an alternative form of media for communicating with the real environment. We propose a 3D virtual world-based add-on architecture that achieves a synchronized virtual-real communication. In this framework, we explored the possibilities of integrating haptic and real world object interactions with Linden Lab's multiuser online 3D virtual world, Second Life. We enhanced the open source Second Life viewer client in order to facilitate communications between the real and virtual world. Moreover, we analyzed the suitability of such an approach in terms of user perception, intuition and other common parameters. Our experiments suggest that the proposed approach not only demonstrates a more intuitive mode of communication system, but also is appealing and useful to the user. Some of the potential applications of the proposed approach include remote child-care, communication between distant lovers, stress recovery, and home automation.
52

AMMP-EXTN: A User Privacy and Collaboration Control Framework for a Multi-User Collaboratory Virtual Reality System

Ma, Wenjun 01 October 2007 (has links)
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.
53

A case study of the manifestations and significance of social presence in a multi-user virtual environment

Cook, Ann D 22 September 2009
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.
54

Design and Development of a Framework to Bridge the Gap Between Real and Virtual

Hossain, SK Alamgir 01 November 2011 (has links)
Several researchers have successfully developed realistic models of real world objects/ phenomena and then have simulated them in the virtual world. In this thesis, we propose the opposite: instantiating virtual world events in the real world. The interactive 3D virtual environment provides a useful, realistic 3D world that resembles objects/phenomena of a real world, but it has limited capability to communicate with the physical environment. We argue that new and intuitive 3D user interfaces, such as 3D virtual environment interfaces, may provide an alternative form of media for communicating with the real environment. We propose a 3D virtual world-based add-on architecture that achieves a synchronized virtual-real communication. In this framework, we explored the possibilities of integrating haptic and real world object interactions with Linden Lab's multiuser online 3D virtual world, Second Life. We enhanced the open source Second Life viewer client in order to facilitate communications between the real and virtual world. Moreover, we analyzed the suitability of such an approach in terms of user perception, intuition and other common parameters. Our experiments suggest that the proposed approach not only demonstrates a more intuitive mode of communication system, but also is appealing and useful to the user. Some of the potential applications of the proposed approach include remote child-care, communication between distant lovers, stress recovery, and home automation.
55

Factors Affecting Human Force Perception and Performance in Haptic-Enabled Virtual Environments

Zadeh, Mehrdad Hosseini January 2009 (has links)
Haptic technology enables computer users to touch and/or manipulate virtual objects in virtual environments (VEs). Similar to other human-in-the-loop applications, haptic applications require interactions between humans and computers. Thus, human-factors studies are required to recognize the limitations and capabilities of the user. This thesis establishes human-factors criteria to improve various haptic applications such as perception-based haptic compression techniques and haptic-enabled computer-aided design (CAD). Today, data compression plays a significant role in the transmission of haptic information since the efficient use of the available bandwidth is a concern. Most lossy haptic compression techniques rely on the limitations of human force perception, and this is used in the design of perception-based haptic compression techniques. Researchers have studied force perception when a user is in static interaction with a stationary object. This thesis focuses on cases where the human user and the object are in relative motion. The limitations of force perception are quantified using psychophysical methods, and the effects of several factors, including user hand velocity and sensory adaptation, are investigated. The results indicate that fewer haptic details need to be calculated or transmitted when the user's hand is in motion. In traditional CAD systems, users usually design virtual prototypes using a mouse via their vision system only, and it is difficult to design curved surfaces due to the number, shape, and position of the curves. Adding haptics to CAD systems enables users to explore and manipulate virtual objects using the sense of touch. In addition, human performance is important in CAD environments. To maintain the accuracy, active haptic manipulation of the user response can be incorporated in CAD applications. This thesis investigates the effect of forces on the accuracy of movement in VEs. The results indicate that factors such as the base force intensity and force increment/decrement can be incorporated in the control of users' movements in VEs. In other words, we can pull/push the users' hands by increasing/decreasing the force without the users being aware of it.
56

Tactile Haptics: A Study of Roughness Perception in Virtual Environments

Samra, Roopkanwal January 2009 (has links)
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.
57

Hållbara projekteringsverktyg : Från byggnadsinformationsmodell till simulering – en utvärdering av Revit och Virtual Environment

Rydberg, Henrik January 2012 (has links)
This study examines the use of building modeling and energy simulations in the design process  of  a  building.  The  take-off  point  is  the  notion  of  energy  simulations  being needed early and throughout the building design process, and that the lack of energy simulations may be explained by the fact that they are time consuming and therefore often too expensive. A greater interoperability between software tools used by relevant disciplines,  such  as  the  architect  and  the  energy  specialist,  would  create  smoother workflows, which would reduce this cost and open up for more frequent and iterative energy  simulation  processes.  The  study  is  an  assessment  of  the  modeling  tool  Revit and  the  simulation  tool  Virtual  Environment  and  whether  they  can  create  smoother workflows, and make leeway for a more frequent use of energy simulations throughout the  design  process.  It  also  investigates  the  limitations  of  what  can  be  examined  by simulations in Virtual Environment. This will hopefully help clarify the future role of energy  simulations  in  design  processes.  The  method  is  a  trial  by  error  approach  of testing the two software tools by building and simulating a model. The results of these tests  show  that  the  workflow  is  not  optimal  (and  therefore  time  consuming)  for frequent  and  iterative simulations  throughout the  design  process,  but  it  also  reveals some  great  possibilities  of  what  can  be  performed  with  these  two  powerful  tools  at hand.  Further  development  with  regards  on  platform  independency  of  the  building information  model,  including  seamless  exporting  and  importing,  seems  necessary  to strengthen the future role of energy simulations.
58

Validation Study of a Virtual Laboratory for Research in Environmental Psychology

Larsson, Marie-France January 2010 (has links)
The aim of this study was to validate the use of a virtual environment (VE) for psychological research. A study made by Maslow and Mintz (1956) in which they found that a room’s aesthetic affects how participants estimate pictures of people was replicated using a VE. A picture of a beautiful room and a picture of an ugly room were projected on an angled screen measuring 185 cm in height and 405 cm in width as to attempt to replicate the effect found in the original study. A total of 31 participants were tested in either the beautiful or the ugly environment. A t-test revealed no significant difference between the groups on the total score given on the pictures. However, a mixed-model ANOVA revealed several significant differences and interaction effects. The results of this study suggest that VE’s could be valid for psychological research, in particular environmental psychological experiments, but that more investigations are needed in order to understand this instrument better.
59

Development tool for push-buttons inside truck cabin

Björertz, Mikael January 2005 (has links)
When developing the driver interface in their trucks, Scania is highly concerned with creating a certain feeling. When pressing a push-button this Scania feeling shall be perceived. It is not obvious what the Scania feeling really is and there is no predefined method to create it. This Master Thesis takes aim at providing the means to improve the process of creating this feeling. First, the Scania feeling was studied via the results of an already made survey at Scania. This survey focused on subjective properties of push-buttons, rotary knobs and levers and related the properties to whether these objects had a Scania feeling or not. This existing data was analyzed statistically. The main task of this Master Thesis, however, was to create an environment where the feeling of a push-button could be tried out and described. This environment was created with a tool from Reachin Technologies AB. The environment is a virtual representation of a push-button module, created with computer haptics and graphics. The environment lets the user interact with a three dimensional view collocated with a force feedback device. The force feedback device lets the user feel what is seen through a pen like interface. The “tip” of the pen is used to touch what is seen in the 3D view. The virtual push-buttons was built from blueprints of real push-buttons to be able to evaluate to what extent the virtual buttons resembled the real ones. The statistical analysis made in this project does not support the notion of describing the Scania feeling with a set of subjective values. The virtual environment created proved to be very life like. The real push-button feeling could be recreated with high precision. When evaluated, the majority of test persons argued that it could be used in the development process.
60

Factors Affecting Human Force Perception and Performance in Haptic-Enabled Virtual Environments

Zadeh, Mehrdad Hosseini January 2009 (has links)
Haptic technology enables computer users to touch and/or manipulate virtual objects in virtual environments (VEs). Similar to other human-in-the-loop applications, haptic applications require interactions between humans and computers. Thus, human-factors studies are required to recognize the limitations and capabilities of the user. This thesis establishes human-factors criteria to improve various haptic applications such as perception-based haptic compression techniques and haptic-enabled computer-aided design (CAD). Today, data compression plays a significant role in the transmission of haptic information since the efficient use of the available bandwidth is a concern. Most lossy haptic compression techniques rely on the limitations of human force perception, and this is used in the design of perception-based haptic compression techniques. Researchers have studied force perception when a user is in static interaction with a stationary object. This thesis focuses on cases where the human user and the object are in relative motion. The limitations of force perception are quantified using psychophysical methods, and the effects of several factors, including user hand velocity and sensory adaptation, are investigated. The results indicate that fewer haptic details need to be calculated or transmitted when the user's hand is in motion. In traditional CAD systems, users usually design virtual prototypes using a mouse via their vision system only, and it is difficult to design curved surfaces due to the number, shape, and position of the curves. Adding haptics to CAD systems enables users to explore and manipulate virtual objects using the sense of touch. In addition, human performance is important in CAD environments. To maintain the accuracy, active haptic manipulation of the user response can be incorporated in CAD applications. This thesis investigates the effect of forces on the accuracy of movement in VEs. The results indicate that factors such as the base force intensity and force increment/decrement can be incorporated in the control of users' movements in VEs. In other words, we can pull/push the users' hands by increasing/decreasing the force without the users being aware of it.

Page generated in 0.1051 seconds