Ontological indeterminacy (OI) involves incompatible conceptual systems being applicable to a domain with equal empirical adequacy; a phenomenon familiar in philosophy, but also present in the sciences and everyday life. This article presents arguments and a detailed use-case showing how OI causes problems for what seems to be a widespread, if implicit, understanding of how semantic Web (SW) terms refer or have meaning, namely: the referent/meaning of a SW term is established through precise definitions given in a formal ontology. We show that this account is incompatible with the key requirement that SW terms/statements be similar in meaning to corresponding natural language terms/statements. We present a new account, based on a “meaning as use” philosophy of language, that avoids these problems by formalizing the distinction between the intention to use a term in a customary manner and the decision to adopt a formal theory that explains or explicates that usage.

The world of computing is becoming a world in which people work, learn, and play together, rather than as single users. This change in people's perspective and expectations will be a major driver of the future of computing. In this paper the convergence of a virtual video club system and a virtual classroom is presented. A single framework for developing multiparty virtual environment applications is explored.

Two problems in the design and deployment of multimedia applications are the lack of design-time and run-time flexibility. In this paper we discuss a general methodology for tackling these issues. The work presented here is an extension of the AlphaOmega framework of [4]. In that framework we showed how the intuitive notion of an object representing its properties and capabilities to other objects differentially could be exploited to provide a powerful but easy way to change the behavior and interfaces of an application, dynamically if desired. In this paper, we develop a formal approach to the basic principles of the AlphaOmega framework. This leads to the definition of a formal system called the αω-calculus. The αω-calculus identifies a set of programming language abstractions that can be consistently added to any object-oriented language. While the calculus captures the intuitive notions underlying the AlphaOmega framework, it also goes beyond the original framework in power and flexibility. We demonstrate the generality of our approach by working with an example that shows how it provides unifying abstractions for such seemingly diverse domains as interactive distance learning and various issues in the area of multimedia documents.

Education and training are expected to change dramatically due to the combined impact of the Internet' and mukimedia technologies.In th~transitional era, we are faced with a di-Iemma: do we design distance learning systems with the present or the Mure in mind?Common sense teIls us that users are more likely to accept innovation if they perceive it as arisiig from within a familiar conte~and therefore we should look to the present for modeIs.But if we cIing to current modeIs, how WI we ever discover and Iearn to expIoit the unique possibilities that surely exist within this marriage?We can design with both the present and the future in mind by using a platform that utilizes a familiar model to start with, but alIows experimentation as users become more comfortable with the technology.The familiar 1 Unlessotherwisenoted we use the term 'Tntemet"in this paper to includeIntranetsas weIL Permission to make digital or hard copies of all orparr of lh~work for personal or classroom use is granted wirhout fee provided ~hat copies are nor made or distnbured for profh or mmmercial advamage, and that copies bear ~h~no~iceand the full citation on the firsI page.TOCOPY olherwise,to republii~to post on servers .. or 10 redisrribrne 10 lisrs, requires prior specific permission andlor a fee.AChi Multimedia'98, Bristol, UK (0 1998 ACM 1-58113-0368198{0008 S5.oo model is that of a course taught by a live instructor using a chzssroom, augmented by other environments.Designing with the future in mind means allowing course designers to experiment with any aspect of this environment they choose to alter.How a virtual room pkztj60rm can be used to achieve this degree of flexibility is a subject for a future paper.In this paper, we discuss an interactive multimedia system called PERSYST that provides the sort of famiIiar environment described above for on-line courses.PERSYST has been used in several distance learning trials; we close this paper with a discussion of the trials and what we have learned from them.1.1

This paper addresses the problem of how to automatically generate visual representations of recorded histories of distributed multimedia collaborations. The work reported here focuses mainly on what we consider to be an innovative approach to this problem, viz., the use of a temporal representation format that displays the generic meta-information associated with multimedia content in a way that lets users focus on and access the associated content of interest. As a concrete example of the use of meta-information, consider a user who would like to access any historical segments containing video of a particular collaborator. A meta-information-based approach can assist in this search by finding all the times at which the known video channel used by that person was in fact operative.

The ability to automatically capture and index multimedia information for later perusal and review is critical to the success of future multimedia services. In this paper, we describe how to automatically generate indexes of real-time streams without requiring deep content analysis. Our techniques involve segmenting continuous audio and video into natural units, and relating these to discrete events from the multimedia application, such as user interactions, control events, and data content. In addition, we describe how to search within multimedia streams using query-based retrieval and visual and auditory retrieval modes. This multimodal retrieval allows for quick browsing and visual comprehension of multimedia streams. Finally we show how our techniques apply to the area of multimedia conference recording.

Integrated circuits, as compared to discrete components, have greatly increased the amount of circuitry that can be mounted on a printed wiring card. Also, board assemblies can be mounted close together, 0.4 inch and less, by taking advantage of low profile flat packs. These packaging efficiencies result in high component densities and significantly smaller equipment, with unfortunately decreased wiring areas.