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A key driver for next generation web information retrieval systems is becoming the degree to which a user’s search and presentation experience is adapted to individual user properties and contexts of use. Over the past decades, two parallel threads of personalisation research have emerged, one originating in the document space in the area of Personalised Information Retrieval (PIR) and the other arising from the hypertext space in the field of Adaptive Hypermedia (AH). PIR typically aims to bias search results towards more personally relevant information by modifying traditional document ranking algorithms. Such techniques tend to represent users with simplified personas (often based on historic interests), enabling the efficient calculation of personalised ranked lists. On the other hand, the field of Adaptive Hypermedia (AH) has addressed the challenge of biasing content retrieval and presentation by adapting towards multiple characteristics. These characteristics, more typically called personalisation “dimensions”, include user goals or prior knowledge, enabling adaptive and personalised result compositions and navigations. The question arises as to whether it is possible to provide a comparison of PIR and AH, where the respective strengths and limitations can be exposed, but also where potential complementary affordances can be identified. This survey investigates the key techniques and impacts in the use of PIR and AH technology in order to identify such affordances and limitations. In particular, the techniques are analysed by examining key activities in the retrieval process, namely (i) query adaptation, (ii) adaptive retrieval and (iii) adaptive result composition and presentation. In each of these areas, the survey identifies individual strengths and limitations. Following this comparison of techniques, the paper also illustrates an example of a potential synergy in a hybridised approach, where adaptation can be tailored in different aspects of PIR and AH systems. Moreover, the concerns resulting from interdependencies and the respective tradeoffs of techniques are discussed, along with potential future directions and remaining challenges. Refereed/Peer-reviewed

We present three fundamental, interrelated approaches to support multiple access paths to each terminal object in information hierarchies: faceted classification, faceted search, and web directories with embedded symbolic links. This survey aims to demonstrate how each approach supports users who seek information from multiple perspectives. We achieve this by exploring each approach, the relationships between these approaches, including tradeoffs, and how they can be used in concert, while focusing on a core set of hypermedia elements common to all. This approach provides a foundation from which to study, understand, and synthesize applications which employ these techniques. This survey does not aim to be comprehensive, but rather focuses on thematic issues.

We present a study to develop an improved understanding of symbolic links in web directories. A symbolic link is a hyperlink which makes a directed connection from a webpage along one path through a directory to a page along another path. While symbolic links are ubiquitous in web directories such as Yahoo!, they are under-studied and, as a result, their uses are poorly understood. A cursory analysis of symbolic links reveals multiple uses: to provide navigational shortcuts deeper into a directory, backlinks to more general categories, and multiclassification. We investigated these uses in the Open Directory Project (ODP), the largest, most comprehensive, and most widely distributed human-compiled taxonomy of links to websites, which makes extensive use of symbolic links. The results reveal that while symbolic links in ODP are used primarily for multiclassification, only few multiclassification links actually span top- and second-level categories. This indicates that most symbolic links in ODP are used to create multiclassification between topics which are nested more than two levels deep and suggests that there may be multiple uses of multiclassification links. We also situate symbolic links vis a vis other semantic and structural link types from hypermedia. We anticipate that the results and relationships identified and discussed in this paper will provide a foundation for (1) users for understanding the usages of symbolic links in a directory, (2) designers to employ symbolic links more effectively when building and maintaining directories and for crafting user interfaces to them, and (3) information retrieval researchers for further study of symbolic links in web directories.

The Web is an enormous set of documents connected through hypertext links created by authors of Web pages. These links have been studied quantitatively, but little has been done so far in order to understand why these links are created. As a first step towards a better understanding, we propose a classification of link types in academic environments on the Web. The classification is multi-faceted and involves different aspects of the source and the target page, the link area and the relationship between the source and the target. Such classification provides an insight into the diverse uses of hypertext links on the Web, and has implications for browsing and ranking in IR systems by differentiating between different types of links. As a case study we classified a sample of links between sites of Israeli academic institutions.

Past research into text retrieval methods for the Web has been restricted by the lack of a test collection capable of supporting experiments which are both realistic and reproducible. The 1.69 million document WT10g collection is proposed as a multi-purpose testbed for experiments with these attributes, in distributed IR, hyperlink algorithms and conventional ad hoc retrieval.WT10g was constructed by selecting from a superset of documents in such a way that desirable corpus properties were preserved or optimised. These properties include: a high degree of inter-server connectivity, integrity of server holdings, inclusion of documents related to a very wide spread of likely queries, and a realistic distribution of server holding sizes. We confirm that WT10g contains exploitable link information using a site (homepage) finding experiment. Our results show that, on this task, Okapi BM25 works better on propagated link anchor text than on full text.WT10g was used in TREC-9 and TREC-2000 and both topic relevance and homepage finding queries and judgments are available.

The results from a series of three experiments that used Text Retrieval Conference (TREC) data and TREC search topics are compared. These experiments each involved three novel user interfaces (one per experiment). User interfaces that made it easier for users to view text were found to improve recall in all three experiments. A distinction was found between a cluster of subjects (a majority of whom were search experts) who tended to read fewer documents more carefully (readers, or exclusives) and subjects who skimmed through more documents without reading them as carefully (skimmers, or inclusives). Skimmers were found to have significantly better recall overall. A major outcome from our experiments at TREC and with the TREC data, is that hypertext interfaces to information retrieval (IR) tasks tend to increase recall. Our interpretation of this pattern of results across the three experiments is that increased interaction with the text (more pages viewed) generally improves recall. Findings from one of the experiments indicated that viewing a greater diversity of text on a single screen (i.e., not just more text per se, but more articles available at once) may also improve recall. In an experiment where a traditional (type-in) query interface was contrasted with a condition where queries were marked up on the text, the improvement in recall due to viewing more text was more pronounced with search novices. Our results demonstrate that markup and hypertext interfaces to text retrieval systems can benefit recall and can also benefit novices. The challenge now will be to find modified versions of hypertext interfaces that can improve precision, as well as recall and that can work with users who prefer to use different types of search strategy or have different types of training and experience.

There are numerous guides on Web design but for the most part, these are based on designers' intuition and common sense — with little theoretical or experimental validation. A major problem is that there is a general lack of cognitive guidelines for Web design. Of the few available theoretical guidelines for designing hypermedia documents, very little experimental research is available that tests the guidelines in a Web context. This study empirically addresses the issue: do home pages designed according to theoretical guidelines lead to better comprehension of information at a Web site? Comprehension was measured along three dimensions: comprehension accuracy, comprehension speed, and perceived comprehension. The results of this study suggest that cognitively designed home pages lead to better comprehension than non-cognitively designed home pages, regardless of whether the home page is primarily graphics-based or text-based. The implications of these results for researchers and practitioners are discussed.

This paper presents a method for solving the collection fusion problem in hypermedia digital libraries. The proposition which is explored and evaluated is that across document links between hypermedia documents residing in distributed hypermedia collections can supply sufficient useful information to allow effective collection fusion. In contrast to other collection fusion strategies, the link-based fusion strategy does not require a learning phase before it can be utilised and, also does not use any information from remote collections other than the returned list of documents. Because of these characteristics the proposed fusion strategy is suitable for very large and extremely dynamic environments in which other collection fusion strategies (e.g. learning collection fusion strategies) may be inapplicable. Evaluation of the link-based fusion strategy demonstrates that the proposed strategy is more effective and efficient than the uniform strategy which can be applied under the same conditions.

This paper describes the development and application of visualisation techniques for users to access and explore information in a digital library effectively and intuitively. Salient semantic structures and citation patterns are extracted from several collections of documents, including the ACM SIGCHI Conference Proceedings (1995–1997) and ACM Hypertext Conference Proceedings (1987–1998), using Latent Semantic Indexing and Pathfinder Network Scaling. The unique spatial metaphor leads to a natural combination of search and navigation within the same semantic space in a 3-dimensional virtual world. Author co-citation patterns are visualised through a number of author co-citation maps in attempts to reveal the structure of the hypertext, including an overall co-citation map of 367 authors and three periodical maps. These maps highlight predominant research areas in the field. This approach provides a means for transcending the boundaries of collections of documents and visualising more profound patterns in terms of semantic structures and co-citation networks.

This paper is an interim report on our efforts at NIST to construct an information discovery tool through the fusion of hypertext and information retrieval (IR) technologies. The tool works by parsing a contiguous document base into smaller documents and inserting semantic links between these documents using document–document similarity measures based on IR techniques. The focus of the paper is a case study in which domain experts evaluate the utility of the tool in the performance of information discovery tasks on a large, dynamic procedural manual. The results of the case study are discussed, and their implications for the design of large-scale automatic hypertext generation systems are described.

The purpose of this study is to carry out a direct comparison of a hypertext-based bibliographic retrieval system with a traditional Boolean-based retrieval system, each using the same database. Novice and experienced searchers were assigned to either a prototype hypertext system called HyperLynx or to a traditional Boolean system and were asked to perform a set of search tasks. The study revealed that the Boolean system performed better than the hypertext system for search tasks with a large number of relevant items. Searcher experience level did not play a significant role for either system. Findings of the study have implications for the design of future information retrieval systems that take advantage of the best features of both approaches for more effective and efficient retrieval of highly structured databases.

Recent advances in multimedia and hypertext have created new opportunities for providing information to business and consumers. Hypermedia has appeared as an important tool for accessing the Internet. Prior hypermedia research mainly has recommended design standards for the interface. The current research models the administrative and operating costs surrounding a hypermedia database, and determines seven conditions for the cost justification of hypermedia. These are (1) higher linking costs proportionately reduce the total number of links implemented; (2) increasing the benefits from using the database increases the total number of links proportionately; (3) increasing database size results in an increase in the total number of links implemented; (4) if the database user learns from the database slowly, then a larger number of links need to be provided; (5) the maximum size of database which is justified on cost will increase as the average cost of linking each node becomes smaller; (6) the total benefit from usage required in order to cost justify a database will decrease as the average cost of linking each node becomes smaller and (7) the maximum size of database which is cost justified will increase rapidly as the learning rate increases—large databases are more easily justified if the users can be assured of picking up useful information when traversing the nodes. The learning rate can be increased by careful construction of links and nodes so that they are maximally informative.

The OtaOnline project at the Helsinki University of Technology has been deploying the distribution of Finnish newspapers such as Iltalehti, Aamulehti and Kauppalehti on the Internet since 1994. The editors produce the electronic counterpart of these papers by a conversion process from QuarkXpress documents to HyperText Markup Language. The project is about to step into a new phase by introducing an approach which provides many new features not available in the old process. This paper describes an object-oriented approach which implements the logical model of a hypermedia newspaper. This model encapsulates the structure of the hypermedia documents as well as their capability for transforming into different presentation formats. It also provides a semantical rating mechanism to be used with intelligent agents. A distribution scheme which enables efficient use of this model is also presented.

The newspaper represents a mature information presentation medium that is well-suited to the display of relatively short, loosely related pieces of text. This work examines the implementation of the newspaper metaphor in an information exploration interface. Based on an analysis of differences between electronic books and electronic newspapers, we submit that the newspaper metaphor is an appropriate interface paradigm for large-scale full-text databases. Similarities between newspapers and hypertext databases lead us to suggest that this metaphor is appropriate for large automatically generated hypertexts, independent of the nature of their content. We describe VOIR, a software prototype that we have used as an electronic newspaper workbench. The program constructs newspaper pages interactively, and allows users to specify their information-seeking intent in a variety of ways, including graphical Boolean queries, hypertext links, and typed-in queries. We report some empirical evidence that indicates that users perform better when they are shown more articles simultaneously. These results suggest that the newspaper metaphor may be an effective organizing principle for a class of information exploration tasks. Finally, we discuss some implications that this work has for hypertext and information retrieval in general.

The first part of the paper briefly introduces what automatic authoring of a hypertext for information retrieval means. The most difficult part of the automatic construction of a hypertext is the creation of links connecting documents or document fragments that are simantically related. Because of this, to many researchers it seemed natural to use IR techniques for this purpose, since IR has always dealt with the construction of relationships between objects mutually relevant. The second part of the paper presents a survey of some of attempts toward the automatic construction of hypertexts for information retrieval. This part will identify and compare scope, advantages and limitations of different approaches. The aim of this survey is to point out the main and most successful current lines of research.

In recent years, information retrieval techniques have been used for automatic generation of semantic hypertext links. This study applies the ideas from the automatic link generation research to attack another important problem in text processing—automatic text summarization. An automatic “general purpose” text summarization tool would be of immense utility in this age of information overload. Using the techniques used (by most automatic hypertext link generation algorithms) for inter-document link generation, we generate intra-document links between passages of a document. Based on the intra-document linkage pattern of a text, we characterize the structure of the text. We apply the knowledge of text structure to do automatic text summarization by passage extraction. We evaluate a set of fifty summaries generated using our techniques by comparing them to paragraph extracts constructed by humans. The automatic summarization methods perform well, especially in view of the fact that the summaries generated by two humans for the same article are surprisingly dissimilar.

We present two methods for evaluating automatically generated hypertext links. The first method is based on correlations between shortest paths in the hypertext structure and a semantic similarity measure. Experimental results with the first method show the degree to which the hypertext conversion process approximates semantic similarity. The semantic measure is in turn only an approximation of a user's internal model of the corpus. Therefore we propose a second evaluation method based on measuring user's performance using hypertext. Finally, we discuss the advantages and disadvantages of computer versus human evaluation, respectively.

Relevance and economic feedback may be used to produce an ordering of documents that supports browsing in hypermedia and digital libraries. Document classification based on the Gray code provides paths through the entire collection, each path traversing each node in the set of documents exactly once. Systems organizing documents based on weighted and unweighted Gray codes are examined. Relevance feedback is used to conceptually organize the collection for an individual to browse, based on that individual's interests and information needs, as reflected by their relevance judgements and user supplied economic preferences. We apply Bayesian learning theory to estimating the characteristics of documents of interest to the user and supply an analytic model of browsing performance, based on minimizing the Expected Browsing Distance (EBD). Economic feedback may be used to change the ordering of documents to benefit the user. Using these techniques, a hypermedia or digital library may order any and all available documents, not just those examined, based on the information provided by the searcher or people with similar interests.

Notions of similarity underlie a wide variety of access methods in hypermedia and information retrieval. This paper describes a research project, in which similarity measures have been extended to include imprecise matching over different dimensions of structured classification schemes (subject, space, time). The semantic similarity of information units forms the basis for the automatic construction of links and is integrated into hypermedia navigation. A semantic hypermedia architecture is outlined, and a prototype museum social history application is described. Illustrative navigation scenarios are presented which make use of a navigation via similarity tool. Three different measures of semantic closeness underpin the similarity tool. The temporal measure takes account of periods as well as time points. The most general measure is based on a traversal of a semantic net, taking into account relationship type and level of specialization. It is based on a notion of closeness rather than absolute distance, and returns a set of semantically close terms. A method of calculating semantic similarity between sets of index terms, based on the maximal closeness values achieved by each term is discussed.

In a research group whose aims include increasing the output of high-quality papers, the keys to organizational success include the hypotheses being researched, collaborative awareness and synergy, and the papers that disseminate the research results. In this paper, we suggest a model for supporting the management of the research group's “production” of papers and implement it in part using information technology. According to the model, if management's information needs regarding the status and process of production are appropriately supported by information technologies, then management can be more focused and effective through gains in awareness and efficiency which are reflected in the group as a whole. As part of the model, a Hypotheses & Papers database was implemented using a collaborative hypertext system (MUCH) which supports alternate outlines and views, providing an information “picture”. The contribution of the database to the group's publishing was evaluated. The database was found to be successful to some extent in supporting management and, indirectly, in enhancing the group's publishing, although it was not considered to be useful by all group members.

The authors investigated how linkage environments in a hypertext-based bibliographic retrieval system affect retrieval performance for novice and experienced searchers. Two systems, one with inter-record linkages to authors and descriptors and one that also included title and abstract keywords, were tested. No significant differences in retrieval performance and system usage were found for most search tests. However, the enhanced system did provide better performance where title and abstract keywords provided the most direct access to relevant records. The findings have implications for the design of bibliographic information retrieval systems using hypertext linkages.