Artificial Intelligence Lab, Department of MIS, University of Arizona / In this paper we report an automatic and scalable concept space approach to enhancing the deep searching capability of the NCSA Mosaic. The research, which is based on the findings from a previous NSF National Collaboratory project and which will be expanded in a new Illinois NSF/ARPA/NASA Digital Library project, centers around semantic retrieval and user customization. Semantic retrieval supports a higher level of abstraction in user search, which can overcome the vocabulary problem for information retrieval. Rather than searching for words within the object space, the search is for terms within a concept space (graph of terms occurring within objects linked to each other by the frequency with which they occur together). Co-occurrence graphs seem to provide good suggestive power in specialized domains, such as biology. By providing a more understandable, system-generated, semantics-rich concept space as an abstraction of the enormously complex object space plus algorithms and interface to assist in object/concept spaces traversal, we believe we can greatly alleviate both information overload and the vocabulary problem of internet services. These techniques will also be used to provide a form of customized retrieval and automatic information routing. Results from past research, the specific algorithms and techniques, and the research plan for enhancing the NCSA Mosaic's search capability in the NSF/ARPA/NASA Digital Library project will be discussed.

Artificial Intelligence Lab, Department of MIS, University of Arizona / Information overload on the Web has created enormous challenges to customers selecting products for online purchases and to online businesses attempting to identify customersâ preferences efficiently. Various recommender systems employing different data representations and recommendation methods are currently used to address these challenges. In this research, we developed a graph model that provides a generic data representation and can support different recommendation methods. To demonstrate its usefulness and flexibility, we developed three recommendation methods: direct retrieval, association mining, and high-degree association retrieval. We used a data set from an online bookstore as our research test-bed. Evaluation results showed that combining product content information and historical customer transaction information achieved more accurate predictions and relevant recommendations than using only collaborative information. However, comparisons among different methods showed that high-degree association retrieval did not perform significantly better than the association mining method or the direct retrieval method in our test-bed.

Artificial Intelligence Lab, Department of MIS, University of Arizona / This research aims to provide a semantic, concept-based retrieval option that could supplement existing information retrieval options. Our proposed approach is based on textual analysis of a large corpus of domain-specific documents in order to generate a large set of subject vocabularies. By adopting cluster analysis techniques to analyze the co-occurrence probabilities of the subject vocabularies, a similarity matrix of vocabularies can be built to represent the important concepts and their weighted “relevance” relationships in the subject domain. To create a network of concepts, which we refer to as the “concept space” for the subject domain, we propose to develop general AI-based graph traversal algorithms and graph matching algorithms to automatically translate a searcher’ s preferred vocabularies into a set of the most semantically relevant terms in the database’s underlying subject domain. By providing a more understandable, system-generated, semantics-rich concept space plus algorithms to assist in concept/information spaces traversal, we believe we can greatly alleviate both information overload and the vocabulary problem. In this chapter, we first review our concept space approach and the associated algorithms in Section 2. In Section 3, we describe our experience in using such an approach. In Section 4, we summarize our research findings and our plan for building a semantics-rich Interspace for the Illinois Digital Library project.

Artificial Intelligence Lab, Department of MIS, University of Arizona / This article presents research on the design of knowledge-based document retrieval systems. We adopted a semantic network structure to represent subject knowledge and classification scheme knowledge and modeled experts' search strategies and user modeling capability as procedural knowledge. These functionalities were incorporated into a prototype knowledge-based retrieval system, Metacat. Our system, the design of which was based on the blackboard architecture, was able to create a user profile, identify task requirements, suggest heuristics-based search strategies, perform semantic-based search assistance, and assist online query refinement.

Artificial Intelligence Lab, Department of MIS, University of Arizona / As applications become more pervasive, pressing, and diverse, several well-known information retrieval (IR) problems have become even more urgent. Information overload, a result of the ease of information creation and transmission via the Internet and WWW, has become more troublesome (e.g., even stockbrokers and elementary school students, heavily exposed to various WWW search engines, are versed in such IR terminology as recall and precision). Significant variations in database formats and structures, the richness of information media (text, audio, and video), and an abundance of multilingual information content also have created severe information interoperability problems -- structural interoperability, media interoperability, and multilingual interoperability.

Artificial Intelligence Lab, Department of MIS, University of Arizona / Two studies were conducted to investigate the cognitive processes involved in online document-based information retrieval. These studies led to the development of five computational models of online document retrieval. These models were then incorporated into the design of an "intelligent" document-based retrieval system. Following a discussion of this system, we discuss the broader implications of our research for the design of information retrieval systems.

Artificial Intelligence Lab, Department of MIS, University of Arizona / This paper summarizes a prototype geographical image retrieval system that demonstrates how to integrate image processing and information analysis techniques to support large-scale content-based image retrieval. By using an image as its interface, the prototype system addresses a troublesome aspect of traditional retrieval models, which require users to have complete knowledge of the low-level features of an image. In addition we describe an experiment to validate the performance of this image retrieval system against that of human subjects in an effort to address the scarcity of research evaluating performance of an algorithm against that of human beings. The results of the experiment indicate that the system could do as well as human subjects in accomplishing the tasks of similarity analysis and image categorization. We also found that under some circumstances texture features of an image are insufficient to represent a geographic image. We believe, however, that our image retrieval system provides a promising approach to integrating image processing techniques and information retrieval algorithms.

Artificial Intelligence Lab, Department of MIS, University of Arizona / The basic problem in information retrieval is that large scale searches can only match terms specified by the user to terms appearing in documents in the digital library collection. Intermediate sources that support term suggestion can thus enhance retrieval by providing altentative search terms for the user. Term suggestion increases the recall, while interaction enables the user to attempt to not decrease the precision. We are building a prototype user interface that will become the Web interface for the University of Illinois Digital Library Initiative (DLI) testbed. It supports the principle of multiple views, wherc different kinds of term suggestors can be used to complement search and each other. This paper discusses its operation with two complementary term suggestors, subject thesauri and co-occurrence lists, and compares their utility. Thesauri are generatad by human indexers and place selected terms in a subject hierarchy. Co-occurrence lists are generated by computer and place all terms in frequency order of occurrence together. This paper concludes with a discussion of how multiple views can help provide good quality Search for the Net. This is a paper about the design of a retrieval system prototype that allows users to simultaneously combine terms offered by different suggestion techniques, not about comparing the merits of each in a systematic and controlled way. It offers no experimental results.

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