Veronique Perret

Dynamic adaptation in an image transcoding proxy for mobile Web browsing

Transcoding proxies are used as intermediaries between generic World Wide Web servers and a variety of client devices in order to adapt to the greatly varying bandwidths of different client communication links and to handle the heterogeneity of possibly small-screened client devices. Such transcoding proxies can adaptively adjust the amount by which a data stream is reduced, using an aggressive lossy compression method (e.g., an image becomes less clear, text is summarized). We present an analytical framework for determining whether to transcode and how much to transcode an image for the two cases of store-and-forward transcoding as well as streamed transcoding. These methods require prediction of transcoding delay, prediction of transcoded image size (in bytes), and estimation of network bandwidth. We discuss methods of adaptation based on fixed quality as well as fixed delay (automated/dynamic transcoding). We conclude with a description of the practical adaptation policies that have been implemented in our adaptive image transcoding proxy.

WebSplitter: a unified XML framework for multi-device collaborative Web browsing

WebSplitter symbolizes the union of pervasive multi-device computing and collaborative multi-user computing. WebSplitter provides a unified XML framework that enables multi-device and multi-user Web browsing. WebSplitter splits a requested Web page and delivers the appropriate partial view of each page to each user, or more accurately to each users set of devices. Multiple users can participate in the same browsing session, as in traditional conferencing groupware. Depending on the access privileges of the user to the different components of content on each page, WebSplitter generates a personalized partial view. WebSplitter further splits the partial view among the devices available to each user, e.g. laptop, wireless PDA, projection display, stereo speakers, orchestrating a composite presentation across the devices. A wireless PDA can browse while remotely controlling the multimedia capabilities of nearby devices. The architecture consists of an XML metadata policy file defining access privileges to XML tags on a Web page, a middleware proxy that splits XML Web content to create partial views, and a client-side component, e.g. applet, enabling user login and reception of pushed browsing data. Service discovery finds and registers proxies, browsing sessions, and device capabilities. We demonstrate the feasibility of splitting the different tags in an XML Web page to different end users browsers, and of pushing updates from the browsing session to heterogeneous devices, including a laptop and a PDA.

Managed portal appliance: an experiment in extending the reach of Web applications

In the typical Web application, a client renders markup and the application or service is implemented as a set of tiered functions in the network. However, clients can contain resources useful for an application and network connections cannot always be assumed. In this paper, we consider extending the reach of a Web application to include: 1) access to and use of local client resources, and 2) operation while disconnected from the network. We, however, try to preserve desirable programming model and management characteristics of Web applications. We propose a system architecture and discuss an initial implementation using a portal as an example Web application.

Quests in a tetherless world

Wireless research activities span a wide range of disciplines: communications engineering, software engineering and computer sciences covering all aspects of communication and services including client platforms and server deployment, network protocols and infrastructure, service development and deployment and so on. Our research group at the IBM T. J. Watson Research Center has initiated a number of research activities covering several aspects of the wireless research. In this paper, we highlight our work on the Bluetooth™ wireless technology and the BlueDrekar™ software stack, the WebSplitter middleware for content distribution, and we will share our vision for interconnecting trillion devices. Copyright