Fabien Costantini

Collaborative learning with the distributed building site metaphor

The authors describe a new approach to interactive and collaborative learning in an industrial training environment. Users learn in the 3D world where multiple instructors can observe, advise, and correct in real time. Our distributed building site metaphor provides distribution services for sharing a virtual world and enables different collaboration styles.

Collaborative design using distributed virtual reality over the Internet

Efficient collaborative virtual environments are missing. First, current solutions do not support mobility to more easily from a disconnected work to a meeting. Second, they do not preserve the consistency or they limit the parallel working. Third, a client-server approach is inefficient in many ways. It introduces a bottleneck and a point of failure in the system. At last, requiring a specific Quality of Service (QoS) from the under laying network limits the ease of deployment. Paper answers these shortages. It enables to distribute a global scene tree among several private spaces. A worker carries out a disconnected work to improve his private space while satisfying protection rules. These different puzzle pieces assemble automatically into a global scene tree during a meeting work. Workers modify in real-time the shared scene. Real time awareness, parallel working and work persistency are provided. A consistency property guarantees the work progression. The solution is fully distributed. Full replication and multicasting improve the performances. A connection facility solves the connectivity problem. It switches automatically from multicast to point-to-point. At last, security is addressed. Standard and secure email enable authentication and distribution of a session key. A re-keying protocol assures confidentiality without requiring communication entities to process X509 certificates.

Collaborative Simulation by Reuse of COTS Simulators with a Reflexive XML Middleware1

Reuse of Commercial Off-The-Shelf simulators is a promising and new approach to support collaborative and distributed simulations. This paper presents ComRTI, a reflexive XML middleware that eases reuse and collaboration between various COTS simulators. It is a portable middleware that runs on Windows and Unix stations. ComRTI uses only widely available software such as TCP/IP and XML toolkits. Heterogeneous simulators cooperate by sharing a neutral XML model. ComRTI eases to manage meta-models and neutral models. It helps to project dynamically a neutral model onto a specific target simulator. ComRTI has proven efficiency to develop cooperation services between industrial designers. Thus, distributed designers cooperate easily by sharing meta-models and reusing their classical simulation interface. The designers can cooperate also by running a distributed simulation involving different meta-models.