Multimedia Information Retrieval

With recent advances in screen and mass storage technology, together with the on-going advances in computer power, many users of personal computers and low end workstations are now regularly manipulating non-textual information. This information may be in the form of drawings, graphs, animations, sound, or video (for example). With the increased usage of these media on computer systems there has not, however, been much work in the provision of access methods to non-textual computer based information. An increasingly common method for accessing large document bases of textual information is free text retrieval. In such systems users typically enter natural language queries. These are then matched against the textual documents in the system. It is often possible for the user to re-formulate a query by providing relevance feedback, this usually takes the form of the user informing the system that certain documents are indeed relevant to the current search. This information, together with the original query, is then used by the retrieval engine to provide an improved list of matched documents. Although free text retrieval provides reasonably effective access to large document bases it does not provide easy access to non-textual information. Various query based access methods to nontextual document bases are presented, but these are all restricted to specific domains and cannot be used in mixed media systems. Hypermedia, on the other hand, is an access method for document bases which is based on the user browsing through the document base rather than issuing queries. A set of interconnected paths are constructed through the base which the user may follow. Although providing poorer access to large document bases the browsing approach does provide very natural access to non-textual information. The recent explosion in hypermedia systems and discussion has been partly due to the requirement for access to mixed media document bases. Some work is reported which presents an integration of free text retrieval based queries with hypermedia. This provides a solution to the scaling problem of browsing based systems, these systems provide access to textual nodes by query or by browsing. Non-textual nodes are, however, still only accessible by browsing - either from the starting point of the document base or from a textual document which matched the query. A model of retrieval for non-textual documents is developed, this model is based on document's context within the hypermedia document base, as opposed to the document's content. If a non-textual document is connected to several textual documents, by paths in the hypermedia, then it is likely that the non-textual document will match the query whenever a high enough proportion of the textual documents match. This model of retrieval uses clustering techniques to calculate a descriptor for non-textual nodes so that they may be retrieved directly in response to a query. To establish that this model of retrieval for non-textual documents is worthwhile an experiment was run which used the text only CACM collection. Each record within the collection was initially treated as if it were non-textual and had a cluster based description calculated based on citations, this cluster based descriptor was then compared with the actual descriptor (calculated from the record's content) to establish how accurate the cluster descriptor was. As a base case the experiment was repeated using randomly created links, as opposed to citations. The results showed that for citation based links the cluster based descriptions had a mean correlating of 0.230 with the content based description (on a range from 0 to 1, where 1 represents a perfect match) and performed approximately six times better than when random links were used (mean random correlation was 0.037). This shows that citation based cluster descriptions of documents are significantly closer to the actual descriptions than random based links, and although the correlation is quite low, the cluster approach provides a useful technique for describing documents. The model of retrieval presented for non-textual documents relies upon a hypermedia structure existing in the document base, since the model cannot work if the documents are not linked together. A user interface to a document base which gives access to a retrieval engine and to hypermedia links can be based around three main categories: browsing only access, use the retrieval engine to support link creation; query only access, use links to provide access to non-text; query and browsing access Although the last user interface may initially appear most suitable for a document base which can support queries and browsing it is also potentially the most complex interface, and may require a more complex model of retrieval for users to successfully search the document base. A set of user tests were carried out to establish user behaviour and to consider interface issues concerning easy access to documents which are held on such document bases. These tests showed that, overall, no access method was clearly better or poorer than any other method. (Abstract shortened by ProQuest.)

Applying digital content management to support localisation

The retrieval and presentation of digital content such as that on the World Wide Web (WWW) is a substantial area of research. While recent years have seen huge expansion in the size of web-based archives that can be searched efficiently by commercial search engines, the presentation of potentially relevant content is still limited to ranked document lists represented by simple text snippets or image keyframe surrogates. There is expanding interest in techniques to personalise the presentation of content to improve the richness and effectiveness of the user experience. One of the most significant challenges to achieving this is the increasingly multilingual nature of this data, and the need to provide suitably localised responses to users based on this content. The Digital Content Management (DCM) track of the Centre for Next Generation Localisation (CNGL) is seeking to develop technologies to support advanced personalised access and presentation of information by combining elements from the existing research areas of Adaptive Hypermedia and Information Retrieval. The combination of these technologies is intended to produce significant improvements in the way users access information. We review key features of these technologies and introduce early ideas for how these technologies can support localisation and localised content before concluding with some impressions of future directions in DCM

Image retrieval by hypertext links

This paper presents a model for retrieval of images from a large World Wide Web based collection. Rather than considering complex visual recognition algorithms, the model presented is based on combining evidence of the text content and hypertext structure of the Web. The paper shows that certain types of query are amply served by this form of representation. It also presents a novel means of gathering relevance judgements

What is the problem to which interactive multimedia is the solution?

This is something of an unusual paper. It serves as both the reason for and the result of a small number of leading academics in the field, coming together to focus on the question that serves as the title to this paper: What is the problem to which interactive multimedia is the solution? Each of the authors addresses this question from their own viewpoint, offering informed insights into the development, implementation and evaluation of multimedia. The result of their collective work was also the focus of a Western Australian Institute of Educational Research seminar, convened at Edith Cowan University on 18 October, 1994. The question posed is deliberately rhetorical - it is asked to allow those represented here to consider what they think are the significant issues in the fast-growing field of multimedia. More directly, the question is also asked here because nobody else has considered it worth asking: for many multimedia is done because it is technically possible, not because it offers anything that is of value or provides the solution to a particular problem. The question, then, is answered in various ways by each of the authors involved and each, in their own way, consider a range of fundamental issues concerning the nature, place and use of multimedia - both in education and in society generally. By way of an introduction, the following provides a unifying context for the various contributions made here

Reviews

The Hutchinson Electronic Encyclopedia, First Electronic Version, Oxford, Random Century and Attica Cybernetics, 1991. ISBN: 1–873472–00–5. Price £99

Capturing flight system test engineering expertise: Lessons learned

Within a few years, JPL will be challenged by the most active mission set in history. Concurrently, flight systems are increasingly more complex. Presently, the knowledge to conduct integration and test of spacecraft and large instruments is held by a few key people, each with many years of experience. JPL is in danger of losing a significant amount of this critical expertise, through retirement, during a period when demand for this expertise is rapidly increasing. The most critical issue at hand is to collect and retain this expertise and develop tools that would ensure the ability to successfully perform the integration and test of future spacecraft and large instruments. The proposed solution was to capture and codity a subset of existing knowledge, and to utilize this captured expertise in knowledge-based systems. First year results and activities planned for the second year of this on-going effort are described. Topics discussed include lessons learned in knowledge acquisition and elicitation techniques, life-cycle paradigms, and rapid prototyping of a knowledge-based advisor (Spacecraft Test Assistant) and a hypermedia browser (Test Engineering Browser). The prototype Spacecraft Test Assistant supports a subset of integration and test activities for flight systems. Browser is a hypermedia tool that allows users easy perusal of spacecraft test topics. A knowledge acquisition tool called ConceptFinder which was developed to search through large volumes of data for related concepts is also described and is modified to semi-automate the process of creating hypertext links

Agents for Distributed Multimedia Information Management

This paper discusses the role of agents in a distributed multimedia information system (DMIS) engineered according to the principles of open hypermedia. It is based on the new generation of Microcosm, an open hypermedia system developed by the Multimedia Research Group at the University of Southampton. Microcosm provides a framework for supporting the three major roles of agents within open information systems: resource discovery, information integrity and navigation assistance. We present Microcosm and its agents, and discuss our current research in applying agent technology in this framework

Bletchley Park text: using mobile and semantic web technologies to support the post-visit use of online museum resources

A number of technologies have been developed to support the museum visitor, with the aim of making their visit more educationally rewarding and/or entertaining. Examples include PDA-based personalized tour guides and virtual reality representations of cultural objects or scenes. Rather than supporting the actual visit, we decided to employ technology to support the post-visitor, that is, encourage follow-up activities among recent visitors to a museum. This allowed us to use the technology in a way that would not detract from the existing curated experience and allow the museum to provide access to additional heritage resources that cannot be presented during the physical visit. Within our application, called Bletchley Park Text, visitors express their interests by sending text (SMS) messages containing suggested keywords using their own mobile phone. The semantic description of the archive of resources is then used to retrieve and organize a collection of content into a personalized web site for use when they get home. Organization of the collection occurs both bottom-up from the semantic description of each item in the collection, and also top-down according to a formal representation of the overall museum story. In designing the interface we aimed to support exploration across the content archive rather than just the search and retrieval of specific resources. The service was developed for the Bletchley Park museum and has since been launched for use by all visitors