CORBA is a commercial standard for distributed object computing which shows great promise in the development of distributed programs. Its interface description language (IDL) enables objects to be developed independently of the underlying programming language, operating system, or computer architecture on which they will execute. While this is sufficient in many environments, programs deployed in a wide-area distributed system encounter conditions which are much more hostile and varying than those operating in a single address space or within a single local area network. In this paper we discuss four major problems we have observed in our developing and deploying wide-area distributed object applications and middleware. First, most programs are developed ignoring the variable wide area conditions. Second, when application programmers do try to handle these conditions, they have great difficulty because these harsh conditions are different from those of the local objects they are used to dealing with. Third, IDL hides information about the tradeoffs any implementation of an object must make. Fourth, there is presently no way to systematically reuse current technology components which deal with these conditions, so code sharing becomes impractical. In this paper we also describe our architecture, Quality of Service for CORBA Objects (QuO), which we have developed to overcome these limitations and integrate their solution by providing QoS abstractions to CORBA objects. First, it makes these conditions first class entities and integrates knowledge of them over time, space, and source. Second, it reduces their variance by masking. Third, it exposes key design decisions of an object's implementation and how it will be used. Fourth, it supports reuse of various architectural components and automatically generates others. © 1997 John Wiley & Sons, Inc.

Architectural support for quality of service for CORBA objects

Recent years have seen a rapid increase in the availability and use of multimedia applications. These systems can generate large amounts of audio and video data which can be expensive to store and unwieldy to access. The Video Mail Retrieval (VMR) project at Cambridge University and Olivetti Research Limited (ORL), Cambridge, UK, is addressing these problems by developing systems to retrieve stored video material using the spoken audio soundtrack [1, 16]. Speci cally, the project focuses on the content-based location, retrieval, and playback of potentially relevant data. The primary goal of the VMR project is to develop a video mail retrieval application for the Medusa multimedia environment developed at ORL. Previous work on the VMR project demonstrated practical retrieval of audio messages using speech recognition for content identi cation [8, 4]. Because of the limited number of available audio messages, a much larger archive of television news broadcasts (along with accompanying subtitle transcriptions) is currently being collected. This will serve as a testbed for new methods of storing and accessing large amounts of audio/video data. The enormous potential size of the news broadcast archive dramatically illustrates the need for ways of automatically nding and retrieving information from the archive. Quantitative experiments demonstrate that Information Retrieval (IR) methods developed for searching text archives can accurately retrieve multimedia data, given suitable subtitle transcriptions. In addition, the same techniques can be used to rapidly locate interesting areas within an individual news broadcast. Although large multimedia archives will be more common in the future, today they require a specialised and highperformance hardware infrastructure. The work presented here relies on the the Medusa system developed at ORL, which includes distributed, high-capacity multimedia repositories. This paper begins with an overview of the ORL Medusa technology. Subsequent sections describe the collection and storage of a BBC television broadcast news archive, a retrieval methodology for location of potentially relevant sections in response to users' requests, and a graphical user interface for content-based retrieval and browsing of news f g

Automatic content-based retrieval of broadcast news

Experiencing flow with instant messaging and its facilitating role on creative behaviors

Synchronous chat reference services have emerged as viable alternatives to the traditional face-to-face (FtF) library reference encounter. Research in virtual reference service (VRS) and client–librarian behavior is just beginning with a primary focus on task issues of accuracy and efficiency. This study is among the first to apply communication theory to an exploration of relational (socioemotional) aspects of VRS. It reports results from a pilot study that analyzed 44 transcripts nominated for the LSSI Samuel Swett Green Award (Library Systems and Services, Germantown, MD) for Exemplary Virtual Reference followed by an analysis of 245 randomly selected anonymous transcripts from Maryland AskUsNow! statewide chat reference service. Transcripts underwent in-depth qualitative content analysis. Results revealed that interpersonal skills important to FtF reference success are present (although modified) in VRS. These include techniques for rapport building, compensation for lack of nonverbal cues, strategies for relationship development, evidence of deference and respect, facesaving tactics, greeting and closing rituals. Results also identified interpersonal communication dynamics present in the chat reference environment, differences in client versus librarian patterns, and compensation strategies for lack of nonverbal communication.

Encountering virtual users: A qualitative investigation of interpersonal communication in chat reference

This paper presents recent work on a multimedia retrieval project at Cambridge University and Olivetti Research Limited (ORL). We present novel techniques that allow extremely rapid audio indexing, at rates approaching several thousand times real time. Unlike other methods, these techniques do not depend on a fixed vocabulary recognition system or on keywords that must be known well in advance. Using statistical methods developed for text, these indexing techniques allow rapid and efficient retrieval and browsing of audio and video documents. This paper presents the project background, the indexing and retrieval techniques, and a video mail retrieval application incorporating content-based audio indexing, retrieval, and browsing.

Open-vocabulary speech indexing for voice and video mail retrieval

The use and deployment of asynchronous transfer mode (ATM) in a target of operating environments and administrative domains are discussed. The operating environments include wide area ATM, regional area ATM, local area ATM, desk area ATM, and local wireless ATM. The challenges of interdomain ATM are reviewed. >

D.L. Tennenhouse

Papers

ATM everywhere