Active Appearance Model (AAM) is an algorithm for fitting a generative model of object shape and appearance to an input image. AAM allows accurate, real-time tracking of human faces in 2D and can be extended to track faces in 3D by constraining its fitting with a linear 3D morphable model. Unfortunately, this AAM-based 3D tracking does not provide adequate accuracy and robustness, as we show in this paper. We introduce a new constraint into AAM fitting that uses depth data from a commodity RGBD camera (Kinect). This addition significantly reduces 3D tracking errors. We also describe how to initialize the 3D morphable face model used in our tracking algorithm by computing its face shape parameters of the user from a batch of tracked frames. The described face tracking algorithm is used in Microsoft's Kinect system.

Numerous mobility solutions have been proposed in the past, but none of them have been widely deployed today. To address the deployment difficulty in previous work, we propose an end-system-based mobility solution for IPv6 (EMIPv6). In our design, we adhere to the end-to-end principle (Saltzer et al., 1984) by directly performing connection maintenance and data packet delivery between the two communicating hosts. And we leverage distributed hash table-based peer-to-peer (P2P) systems to carry out self-organized, scalable, and robust name lookup for mobile hosts. When the mobility messages such as address updates cannot be delivered directly between the end hosts (e.g., due to firewalls, network address translators, or simultaneous movement), we propose a distributed subscription/notification (S/N) service on top of the previously introduced P2P overlay to deliver them. This leads to a complete end-system solution with small handoff latency and efficient packet delivery. Our simulation results showed that our scheme achieves small name resolution latency by considering host heterogeneity into the design. We have implemented EMIPv6-based end-systems. The experiments in our testbed demonstrated that a complete end-system-based mobility solution is technically feasible and is easy to deploy in the real world without the need of introducing new network components.

This paper describes the INRIA videoconferencing system (IVS), a low bandwidth tool for real-time video between workstations on the Internet using UDP datagrams and the IP multicast extension. The video coder-decoder (codec) is a software implementation of the ITU-T recommendation H.261 originally developed for the integrated services digital network (ISDN). Our focus is on adapting this codec for the Internet environment. We propose a packetization scheme, an error control scheme and an output rate control scheme that adapts the image coding process based on network conditions. This work shows that it is possible to maintain videoconferences with reasonable quality across packet-switched networks without requiring special support from the network such as resource reservation or admission control.

Isolated network are currently being integrated in order to create a universal and virtual inter-network. In this context, the existence of a common authentication infrastructure is extremely important. CCITT Recommendation X.509 defines a public key-based "Authentication Framework" in which the Directory Service can be used to provide key management facilities for open applications. We propose a new approach to X.509 comprising a modular reorganization of the overall system and mechanisms allowing the realization of a global infrastructure for the deployment of authentication-based secure services. These mechanisms aim to complete the X.509 framework so as to rectify some open issues of the approach in order to allow the support of a multitude of trust models while respecting each security domain's certificates validation criteria. We first discuss aspects related to authentication data retrieval and validation with respect to X.509. Then we give an overview of the overall approach, and emphasize its more relevant aspects and mechanisms while describing the applicability of our approach with respect to security architectures and current trust models. Finally, we conclude the paper describing the applicability of our approach in a open and heterogeneous environment.>

The design issues of a multimedia transport protocol, TP5, which achieves the multiplexing of both real time and normal data flows at the transport layer are discussed. The use of a single transport connection to carry both data flows is proposed. Two schemes for the support of the synchronization of these data flows are presented. The protocol TP5 implementing the above mechanisms is described. It is shown that with the use of the described synchronization schemes, the TP5 protocol minimizes the control of the real time traffic while still controlling the normal data flow.>

One of the first applications of satellite telecommunication systems being studied within the NADIR pilot project is high speed (several Mbits/s) file transfer. After a short description of the French “TELECOM 1” satellite communication system, the paper points out that usual protocols such as HDLC cannot be simply adapted to fit satellite transmission requirements (high bandwidth, long propagation delay and various error rates). Specific problems, such as choice of frame length, error correction procedure, numbering scheme, and flow control mechanism are discussed, and a set of feasible solutions to be experimented are proposed.