The design of services to support continuous media differs significantly from that of services to support only traditional textual data. The continuous media applications have an implied temporal dimension, i.e. they are presented at a particular rate for a particular length of time and if the required rate of presentation is not met the integrity of these media is destroyed. We present a set of language constructs suitable for the definition of the required QoS and the real-time dimension of the media that participate in a multimedia application. We study also new methods that provide low-level support to these language constructs and supply at runtime the required level of QoS requirements to a set of distributed multimedia applications.

In this paper, we present a new technique to capture and index computer-based activities, without hindering natural human-computer interactions. This technique is based on the Virtual Network Computing (VNC) technology, which is an ultra-thin-client/server computing model that separates the display interface from the application logic in windowing systems. The server executes all the applications and the client simply presents the frame buffer updates to the user and accepts user input. We record the frame buffer updates for work review, and store the user and system events as potential indices into the recording.

In this research, we propose a flexible subblock image retrieval algorithm which is robust to object translation, lighting change, object appearance or disappearance in an image which is divided into 9 non-overlapping subblocks. Furthermore, using Ohta-color moments and biorthogonal wavelet frames from each subblock, we can reduce the dimension of color space and improve the performance. Also, as the two features are applied to the multi-step k-nearest neighbor algorithm, this system clearly outperforms the global color histogram, RGB moments, and HSI moments using the same method. In addition, we provide another retrieval environment for the user which is a relative block location search as well as an absolute block location search. In the case of the block location search, the user selects a block the user wants to search.

This article focuses on the use of Virtual Reality in the creation of Information Visualization systems and applications aiming to generate more interactive and easy-friendly visualizations. The development of the InfoVis tool, created as part of a virtual environment, is described and discussed with emphasis on implementation aspects.

The HyTech Digital Library Project focuses on development of hypermedia technology for a special kind of digital library that provides support for scholarly work. This paper presents the requirements for HyTech, which were identified by analyzing a particular case study namely ACM SIGWEB's Digital Library Project.

This paper presents a model for describing the synchronization between several media delivered over a network in a Web-based environment. Synchronization concerns the download and the activation of coordinated media files according to the structure of the whole hypermedia document, the playback status of the media objects, and the user interaction. The model defines five synchronization primitives some of which can be automatically deducted from the document structure and the media-related events. The model is oriented to describe applications based on a main video or audio narration to which static or dynamic documents are attached. The model is suited for applications like distance education, professional training, Web advertising and selling, and news-on-demand.