This demonstration presents the current state of an on-going team project at Simon Fraser University in developing a virtual environment for helping to train surgeons in performing laparoscopic surgery. In collaboration with surgeons, an initial set of training procedures has been developed. Our goal has been to develop procedures in each of several general categories, such as basic hand-eye coordination, single-handed and bi-manual approaches and dexterous manipulation. The environment is based on an effective data structure that offers fast graphics and physically based modeling of both rigid and deformable objects. In addition, the environment supports both 3D and 5D input devices and devices generating haptic feedback. The demonstration allows users to interact with a scene using a haptic device.

An experiment was conducted to investigate how performance of a reach, grasp and place task was influenced by added auditory and graphical cues. The cues were presented at points in the task, specifically when making contact for grasping or placing the object, and were presented in single or in combined modalities. Haptic feedback was present always during physical interaction with the object. The auditory and graphical cues provided enhanced feedback about making contact between hand and object and between object and table. Also, the task was performed with or without vision of hand. Movements were slower without vision of hand. Providing auditory cues clearly facilitated performance, while graphical contact cues had no additional effect. Implications are discussed for various uses of auditory displays in virtual environments.

This work explores how the availability of visual and haptic feedback affects and kinematics of reaching performance in a tabletop virtual environment. Eight subjects performed reach-to-grasp movements toward target objects of various sites in conitions where visual and haptic feedback were either present or absent. It was found that movement time was slower when visual feedback of the moving limb was not available. Further MT varied systematically with target size when haptic feedback was available (i.e. augmented targets), and thus followed Fitts' law. However, movement times were constant regardless of target size when haptic feedback was removed. In depth analysis of the reaching kinematics revealed that subjects spent longer decelerating toward smaller targets in conditions where haptic feedback was available. In contrast, deceleration time was constant when haptic feedback was absent. These results suggest that visual feedback about the moving limb and veridical haptic feedback about object contract are extremely important for humans to effectively work in virtual environments.

An experiment was conducted to investigate the role of surrounding haptic and visual information on object manipulation in a virtual environment. The contextual haptic constraints were implemented with a physical table and the contextual visual constraints included a checkerboard background (“virtual table”). It was found that the contextual haptic constraints (the physical table surface) dramatically increased object manipulation speed, but slightly reduced spatial accuracy, compared to free space. The contextual visual constraints (presence of the checkerboard) actually showed detrimental effects on both object manipulation speed and accuracy. Implications of these findings for human-computer interaction design are discussed.

An experiment was conducted to systematically investigate combined effects of controller, cursor and target size on multidimensional object manipulation in a virtual environment. It was found that it was the relative size of controller, cursor and target that significantly affe&d object transportation and orientation processes. There were significant interactions between controller size and cursor size as well as between cursor size and target size on the total task completion time, transportation time, orientation time and spatial errors. The same size of controller and cursor improved object manipulation speed, and the same size of cursor and target generally facilitated object manipulation accuracy, regardless of their absolute sizes. Implications of these findings for human-computer interaction design are discussed.

The Virtual Hand Lab (VHL) is an an augmented reality envimnment for conducting experiments in human perception and motor performance that involve grasping, manipulation, and other 3D tasks that people perform with their hands.The hardware and software testbed supports both physical and virtual objects, and object behaviors that cm be specified in advance by experimenters.A testbed for conducting experiments must provide visual stimuli that depend on the configuration of the experimental apparatus, on the specific tasks that are being studied, and on the individual characteristics of each subject.Calibration is an important concern and is the subject of this paper.A proper design leads to independent calibration steps that modularize the subsystems that require calibration and explicitly recognize and order the dependencies among them.We describe how the architecture for the VHL was designed to support independent apparatus-specific, experiment-specific, and subject-specific calibrations.The architecture offers benefits for any augmented reality environment by reducing m-calibration times and identifying appropriate modularization in the software that can result in a more robust and efficient implementation.

An experiment was conducted to investigate the relationship between object transportation and object orientation by the human hand in the context of humancomputer interaction (HCI). This work merges two streams of research: the structure of interactive manipulation in HCI and the natural hand prehension in human motor control. It was found that object transportation and object orientation have a parallel, interdependent structure which is generally persistent over different visual feedback conditions. The notion of concurrency and interdependence of multidimensional visuomotor control structure can provide a new framework for human-computer interface evaluation and design. Keywords Direct manipulation, input device, multi-dimensional control, visuomotor control, visual conditions, information processing, interface design, virtual reality. INTRODUCTION Object manipulation is a basic operation in humancomputer interaction (HCI). Modern computer technology advances towards affording m...

The keystroke dynamics of a computer user's login string provide a characteristic pattern that can be used for identity verification. Timing vectors for several hundred login attempts were collected for ten "valid" users and ten "forgers", and classification analysis was applied to discriminate between them. Three different classifiers were applied, and in each case the key hold times were more effective features for discrimination than the interkey times. Best performance was achieved by an inductive learning classifier using both interkey and hold times. A high rate of typographical errors during login entry is reported. In practice, these are usually corrected errors-that is, they are strings which include backspaces to correct earlier errors-but their presence confounds the use of typing-style analysis as a practical means of securing access to computer systems.

Article Free Access Share on Physical versus virtual pointing Authors: Evan D. Graham School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada V5A 1S6 School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada V5A 1S6View Profile , Christine L. MacKenzie School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada V5A 1S6 School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada V5A 1S6View Profile Authors Info & Claims CHI '96: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1996 Pages 292–299https://doi.org/10.1145/238386.238532Published:13 April 1996Publication History 41citation1,159DownloadsMetricsTotal Citations41Total Downloads1,159Last 12 Months51Last 6 weeks7 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteView all FormatsPDF