In interventional radiology, physicians require high haptic sensitivity and fine motor skills development because of the limited real-time visual feedback of the surgical site. The transfer of this type of surgical skill to novices is a challenging issue. This paper presents a study on the design of a biopsy procedure learning system. Our methodology, based on a task-centered design approach, aims to bring out new design rules for virtual learning environments. A new collaborative haptic training paradigm is introduced to support human-haptic interaction in a virtual environment. The interaction paradigm supports haptic communication between two distant users to teach a surgical skill. In order to evaluate this paradigm, a user experiment was conducted. Sixty volunteer medical students participated in the study to assess the influence of the teaching method on their performance in a biopsy procedure task. The results show that to transfer the skills, the combination of haptic communication with verbal and visual communications improves the novices’ performance compared to conventional teaching methods. Furthermore, the results show that, depending on the teaching method, participants developed different needle insertion profiles. We conclude that our interaction paradigm facilitates expert-novice haptic communication and improves skills transfer; and new skills acquisition depends on the availability of different communication channels between experts and novices. Our findings indicate that the traditional fellowship methods in surgery should evolve to an off-patient collaborative environment that will continue to support visual and verbal communication, but also haptic communication, in order to achieve a better and more complete skills training.

a b s t r a c tWith the advent of new haptic feedback devices, researchers are giving serious consideration to the incorporation of haptic communication in collaborative virtual environments. For instance, haptic interactions based tools can be used for medical and related education whereby students can train in minimal invasive surgery using virtual reality before approaching human subjects. To design virtual environments that support haptic communication, a deeper understanding of humans 0 haptic interactions is required. In this paper, human 0 s haptic collaboration is investigated. A collaborative virtual environment was designed to support performing a shared manual task. To evaluate this system, 60 medical students participated to an experimental study. Participants were asked to perform in dyads a needle insertion task after a training period. Results show that compared to conventional training methods, a visual-haptic training improves user 0 s collaborative performance. In addition, we found that haptic interaction influences the partners 0 verbal communication when sharing haptic information. This indicates that the haptic communication training changes the nature of the users 0 mental representations. Finally, we found that haptic interactions increased the sense of copresence in the virtual environment: haptic communication facilitates users 0 collaboration in a shared manual task within a shared virtual environment. Design implications for including haptic communication in virtual environments are outlined.

Using a simple cylindrical model for the colon and reducing drift by registering band images allows for the generation of visibility maps. The current results also suggest that the provided feedback through the visibility map could enhance clinicians' awareness of uncovered areas, which in return could reduce the probability of missing polyps.

We present a new graphical three-dimensional user interface for synchronous cooperative work, called Spin, designed for multi-user real-time applications to be used in, for example, meetings and learning situations.We have designed an interface, for an office environment, which recreates the three-dimensional elements needed during a meeting and increases the user's scope of interaction in comparison to a real-life situation. In order to accomplish these objectives, animation and three-dimensional interaction in real time are used to enhance the feeling of collaboration within the three-dimensional workspace and keep visible a maximum of information. This workspace is created using artificial geometry -as opposed to true threedimensional geometry -and spatial distortion, a technique which allows all the documents and information to be displayed simultaneously while centering the user's focus of attention. Users interact with each other via their respective clone, a three-dimensional representation, displayed in each interlocutor interface, and animated with user action on shared documents. An appropriate object manipulation system is used to point out and manipulate 3D documents, through direct manipulation, using 3D device and some interaction metaphors. Keywords: Synchronous CSCW, three-dimensional interface, 3D interaction. IntroductionTechnological progress has given us access to fields which previously only existed in our imaginations. Progress made in computers and in communications networks has benefited computer-supported cooperative work (CSCW), an area where many technical and human obstacles have to be overcome if it is to be considered a valid tool. We need to bear in mind the difficulties inherent in cooperative work and in the user's ability to perceive a third dimension. The shortcomings of two-dimensional interfacesCurrent WIMP ( Windows Icon Mouse Pointer) office interfaces have considerable ergonomic limitations. Two-dimensional space is not effective when it comes to displaying massive amounts of data; this results in shortcomings such as window overlapping and the need for iconic representation of information. Window display systems, be they Xll or Windows, do not make the distinction between applications, and information is displayed in identical windows regardless of the user's task.Until recently, network technology only allowed for asynchronous sessions; and because the hardware being used was not powerful enough, interfaces could only use two-dimensional representations of the workspace. This created many problems: moving within the simulated three-dimensional space was limited, metaphors were not realistic, there were difficulties representing users and their relation to the interface. Moreover, because graphical interaction was low (proprioception was not exploited) users had difficulties to get themselves involved in the outstanding task. Interfaces: New ScopeWe are putting forward a new interface concept, based on computer animation in real time. Widespread use of 3D graphics...