This paper presents the constraints involved by MPEG-4 to copyright protection systems based upon watermarking technology. It proposes also an assessment methodology in order to evaluate such systems in terms of robustness to compression and quality.
The ACTS project MOVE currently designs and develops a middleware architecture called Voice-Enabled Mobile Application Support Environment (VE-MASE). The VE-MASE enhances the middleware architecture, which was developed in the ACTS project OnThe-Move, by providing support for interactive real-time multimedia applications and integrated voice and data services. In preparation for future 3rd generation mobile networks, the aim is to enable a completely new class of interactive multimedia services targeted at, but not limited to, mobile devices that are equipped with the VE-MASE. This paper discusses the VE-MASE component called Audio Gateway, which is responsible for providing Internet Telephony services to mobile users.
The objectives of the CATI project (Charging and Accounting Technology for the Internet) include the design, implementation, and evaluation of charging and accounting mechanisms for Internet services and Virtual Private Networks (VPN). They include the enabling technology support for open, Internet-based Electronic Commerce platforms in terms of usage-based transport service charging as well as high-quality Internet transport services and its advanced and flexible configurations for VPNs. In addition, security-relevant and trust-related issues in charging, accounting, and billing processes are investigated. Important application scenarios, such as an Internet telephony application as well as an Electronic Commerce shopping network, demonstrate the applicability and efficiency of the developed approaches. This work is complemented by an appropriate cost model for Internet communication services, including investigations of suitable usage-sensitive pricing models.
In this paper, we propose a transport layer protocol for onetomany multicast that is designed to have good scalability properties in large receiver groups and provides reliable transmission. Reliability is achieved using forward error correction (FEC) in combination with selective repeat NAK-based ARQ. Using FEC can significantly reduce the necessity for retransmission requests or make them totally unnecessary, which is important in wireless and satellite communicaton environments, as well as for delay-sensitive multimedia applications. The protocol uses one multicast group address for the original transmission and a second group address for the handling of retransmissions, which helps in significantly reducing the network load on branches with low loss and facilitates usage in the context of satellite communications. We hope that our work will be useful and encouraging for the development of group communication applications.
This paper develops a methodology consisting of improved previously known methods and novel techniques for the model based coding of a human face. An image scene is analysed to locate the position of human faces and transform a generic three dimensional face model to reflect the characteristics extracted from the particular image. A set of feature points necessary to define the position and posture of the face is tracked through the image sequence and the three dimensional model is continuously adapted to the facial image of every subsequent frame. Results are shown for every individual module, while on going work aims to the integration of the component modules.
The MPEG-2 standard has allowed Digital Television to become a reality at reasonable costs. The introduction of MPEG-4 will allow content and service providers to enrich MPEG-2 content with new 2D and 3D scenes capable of a high degree of interactivity even in broadcast environments. While ensuring compatibility with existing terminals, the user of the new terminal will be provided with other applications, such as Electronic Program Guides, Advanced Teletext, but also a new non-intrusive kind of advertisements. For these reasons, a scalable device opened both to the consolidated past (MPEG-2) and to the incoming future (MPEG-4) is considered a key issue for the delivery of new services. The presence of a Java Virtual Machine and a set of standard APIs is foreseen in the current terminal architecture, to give extended programmatic capabilities to content creators. This paper covers the application areas, the design and the implementation of a prototype for this terminal, which has been developed in the context of the ACTS SOMMIT project.
The paper describes a methodology for performing quantitative risk analysis of multimedia projects, as developed in the ACTS projects OPTIMUM and TERA. A framework for risk analysis is presented, encompassing key elements such as choice of probability density functions, correlation between important variables, simulation performance, methodology for cost predictions, demand forecasts, tariff predictions and associated uncertainties. The TERA tool for techno-economic evaluation is presented and the important steps in network evaluation identified. The paper examines how much the most critical factors contribute to the overall risk profile of telecommunications operator projects and studies the dependencies between variables.
This paper describes the methodology and procedure of usability trials undertaken as part of the ACTS Teleshoppe project; it also details and analyses the results of the trials. The aim of the trials was to assess user attitudes to a collaborative shared-space shopping service. Usability data were obtained using a series of Likert-style questionnaires and through a ‘focus group’ discussion performed with a representative subset of the trial participants. The paper presents this data and draws conclusions relevant to the future direction of research and implementation for such shopping services. In particular, the results of the trials indicate a generally positive attitude towards the collaborative shopping service used. Furthermore, those aspects of the service viewed negatively by the users are for the most part aspects which can be easily rectified and not due to technological limitations.
This paper introduces the Terrestrial Digital Video Broadcasting DVB-T, stating its innovative aspects and its major advantages for data broadcasting, particularly TV broadcasting. It also presents the experimental DVB-T network built up by Retevisión in the framework of the Spanish VIDITER project (Terrestrial Digital Video) and the European ACTS VALIDATE (Verification and launch of Integrated Digital Advanced Television in Europe) and ACTS MOTIVATE projects (Mobile Television and Innovative Receivers). The experience and some of the results of the different tests carried out by Retevisión are afterwards discussed.
The provision of interactive multimedia services, such as video-on-demand, teleshoping and distance learning, to a large number of users, still remains a challenging issue in the multimedia area. Despite of recent technological advances in all levels of the distributed multimedia infrastructure (storage, network, compression, standardization etc..), there is a strong need for feedback from public trials. Trial descriptions and evaluations, by revealing potential system limitations and measuring end user reactions, will provide valuable input towards the large-scale deployment of such services. In this paper, we present the teleteaching trial that was held at the end of 1998, at Limburg University (Belgium), in the context of ACTS SICMA project. We describe in detail the overall architecture and present results/implementation experiences for the parts of the system, putting the main emphasis on the server. We present technical integration issues between DAVIC and Internet server protocols (RTSP, DSM-CC etc..), and discuss the overall trial results.
With the increasing number of MBone sessions the interest of home users to participate in multicast sessions is also increasing. Unfortunately the cost for the hardware necessary to participate in multicast sessions over a high speed link are still prohibitively high. This paper discusses technical problems and solutions for users who wish to participate in multicast sessions over dial-in lines and presents our approach, the Dial-In Multicast Gateway, which meets the requirements for an application layer multicast router with a restrictive broadcasting policy and a dynamic tunneling mechanism. The Dial-In Multicast Gateway allows the transmission of selected multicast sessions over dial-in connections such as modems, ISDN or even new network access technologies like ADSL by providing a mechanism to configure a multicast tunnel dynamically. For each selected media stream the desired quality of service parameters can be set interactively, e.g. a certain share of the available bandwidth can be reserved. In order to allow a graceful scaling of video we integrated a simple scaling mechanism for H.261 video streams that controls the temporal resolution of the video.
This document presents an architecture for native ATM videoconference based on H.323, which takes advantage of ATM QOS characteristics. The ATM addressing scheme is used, and the transport functions are performed by ATM related protocols. This architecture allows the definition of different QOS requirements for audio and video, using the RTP/RTCP mechanism to adapt media quality to the capabilities of the terminals. The audiovisual data distribution in a multipoint-to-multipoint videoconference is decentralised, and based on ATM point-to-multipoint connections without requiring an MCU. This architecture was the framework for the development of a prototype videoconference application, whose performance measurements are presented and discussed.
Multimedia-based interfaces to complex services are difficult to create and maintain. An architecture for multimedia presentation systems has been developed in the KIMSAC project, based on a sharp separation between the services and their associated multimedia interfaces. The architecture supports flexibility in designing the multimedia dialogues for individual services, ranging from dialogues that are designed in great detail, to dialogues that are specified only in intentional ways and for which their presentations can be generated or adapted to the context of their use. Specific attention has been given to the needs that characterize open service environments exposed to the public at large. In such environments potentially independent services are accessed in parallel, introducing problems in managing the interleaving of dialogues with several services. The resulting architecture is compared to existing models for UIMS, highlighting the needs to refine these models when applying them to open service environments.
Existing communications systems are rapidly converging into an ubiquitous information infrastructure that does not distinguish between computing and communications, but rather provides a set of distributed services to the user. The research community must be prepared to foresee these changes and to deal with them, enlarging the space of technical possibilities so as to make available to society's needs new valuable choices. In this scenario the capability of the network to provide the applications with end-to-end Quality of Service (QoS) becomes a central issue. An engineering approach is needed in this research field in order to incrementally build the next-generation network. This paper focuses on some of the hot topics related to end-to-end QoS provisioning over the Internet and aims at exploiting the current proposals of the research community, while looking at them from a critical point of view and providing actual implementation of some of the discussed ideas. Thus, we propose a QoS-capable architecture aiming at providing flexible and effective implementation of the Integrated Services model via a Weighted Fair Queueing scheduling mechanism, while defining a new service class capable of giving long-term rate guarantees to Internet flows.
Digital television services are now available in various countries in Europe and throughout the world featuring applications such as Electronic Program Guide and Digital Teletext. Future applications will combine television, real-time data broadcast and eventually Internet access to offer value-added services and Electronic Commerce applications for the residential use. This paper discusses possible approaches to implement and to manage applications for enhanced digital television services which exploit the broadcast technology by adding interactivity and multimedia. A production system is described, which provides means to address the specific characteristics of the broadcast environment. The ideas presented in this paper stem from the experience gained during the ACTS IMMP Project.
This document presents some new network operator services possible to deploy on an advanced Internet. These new services are placed in the context of current standardization activities under development in the IETF (Internet Engineering Task Force). In particular, both quality of service and PSTN (Public Switched Telephone Network) interoperation are discussed, and emphasis is placed on multimedia applications. Final comments present some operational and management issues in this new environment.
A chargeable session on the Internet may consist of more than one underlying chargeable service. Typically there will be two, one at the network layer and one at the session layer. Since different applications can have different demands from the Network, a generic charging scheme has to separate the service provided by the network from the service provided by an application/service provider. In this paper we propose a pricing model which is session based and we look at the impact of this on real-time multimedia conferencing over the Internet. In this model, we are trying to allow for the optional integration of charging at the network layer with charging at the session layer, while keeping the underlying technologies still cleanly apart. This paper also highlights the fact that the main problem of pricing application on the Internet is not just a simple case of analyzing the most technically feasible pricing mechanism but also making the solution acceptable to users. We take the position that session based pricing is easier for end users to accept and understand and show why this is the case in this paper.
One of the goals of the ACTS project MODEST is to build an automatic video-surveillance system from a sequence of digital images. The overall system can be divided into the following sub-tasks which are of great interest in the representation of images, namely the automatic segmentation of the video-surveillance sequences, and the extraction of descriptors (such as those in MPEG-7) to represent the objects in the scene and their behaviors.
This paper describes a 3D model-based unsupervised procedure for the segmentation of multiview image sequences using multiple sources of information. Using multiview information a 3D model representation of the scene is constructed. The articulation procedure is based on the homogeneity of parameters, such as rigid 3D motion, color and depth, estimated for each sub-object, which consists of a number of interconnected triangles of the 3D model. The rigid 3D motion of each sub-object for subsequent frames is estimated using a Kalman filtering algorithm taking into account the temporal correlation between consecutive frames. Information from all cameras is combined during the formation of the equations for the rigid 3D motion parameters. The parameter estimation for each sub-object and the 3D model segmentation procedures are interleaved and repeated iteratively until a satisfactory object segmentation emerges. The performance of the resulting segmentation method is evaluated experimentally.
