Maristella Agosti

Evaluation of digital libraries

Digital libraries (DLs) are new and innovative information systems, under constant development and change, and therefore evaluation is of critical importance to ensure not only their correct evolution but also their acceptance by the user and application communities. The Evaluation activity of the DELOS Network of Excellence has performed a large-scale survey of current DL evaluation activities. This study has resulted in a description of the state of the art in the field, which is presented in this paper. The paper also proposes a new framework for the evaluation of DLs, as well as for recording, describing and analyzing the related research field. The framework includes a methodology for the classification of current evaluation procedures. The objective is to provide a set of flexible and adaptable guidelines for DL evaluation.

A formal model of annotations of digital content

This article is a study of the themes and issues concerning the annotation of digital contents, such as textual documents, images, and multimedia documents in general. These digital contents are automatically managed by different kinds of digital library management systems and more generally by different kinds of information management systems. Even though this topic has already been partially studied by other researchers, the previous research work on annotations has left many open issues. These issues concern the lack of clarity about what an annotation is, what its features are, and how it is used. These issues are mainly due to the fact that models and systems for annotations have only been developed for specific purposes. As a result, there is only a fragmentary picture of the annotation and its management, and this is tied to specific contexts of use and lacks-general validity. The aim of the article is to provide a unified and integrated picture of the annotation, ranging from defining what an annotation is to providing a formal model. The key ideas of the model are: the distinction between the meaning and the sign of the annotation, which represent the semantics and the materialization of an annotation, respectively; the clear formalization of the temporal dimension involved with annotations; and the introduction of a distributed hypertext between digital contents and annotations. Therefore, the proposed formal model captures both syntactic and semantic aspects of the annotations. Furthermore, it is built on previously existing models and may be seen as an extension of them.

Lectures on information retrieval

Information Retrieval (IR) is concerned with the effective and efficient retrieval of information based on its semantic content. The central problem in IR is the quest to find the set of relevant documents, among a large collection containing the information sought, satisfying a users information need usually expressed in a natural language query. Documents may be objects or items in any medium: text, image, audio, or indeed a mixture of all three.

A two-level hypertext retrieval model for legal data

This paper introduces an associative information retrieval model based on the two-level architecture proposed in [Agosti et al, 1989a] and[Agostiet al, 1990], andan experimental prototype developed in order to validate the model in a personal computing environment. In the fiist part of the paper, related work and motivations are presented. In the second pert, the model, entitled EXPLICIT, is introduced. EXPLICIT is basedon a two-level architecture which holds the two main parts of the informative resource managed by an information retrieval tool: the collection of documents and the indexing term structure. Theterm structure is managed as a schema of concepts which can be used by the final user as a frame of reference in the query formulation process. llemodel supports theconcurrent use of different schemas of concepts to satisfy information needs of different categories of users. Inthethird part of the paper, the main characteristics of the experimental prototype, named HyperLaw, are presented. 1. ASSOCIATIVE INFORMATION RETRIEVAL AND MOTIVATIONS OF THE WORK Associative information retrieval methods are all those retrieval methods which have been proposed and experimented since 1975 [Doyle, 1975] in order to expand query formulation by adding to an initial query some new terms related to the Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republieh, requiree a fee and/or epecific permission. @ 1991 ACM O-89791 .448 -l/91 /0009 /0316 . ..

On the use of information retrieval techniques for the automatic construction of hypertext

5050 terms of the initial query, and similarly expanding the retrieved document set using terms related to the already used terms [Salton & Buckley, 1988]. [Salton & Buckley, 1988] contains an up-to-date situation in designing and usage of associative information retrieval methods and shows that the difficulty encountered in applying associative retrieval methods still resides in the identification of related terms and documents which would improve retrieval operations. Concerning the currently available information retrieval systems, the most common situation is that of the user who is unable to actively interact with the indexing term structure used by the system. That is, the user is able to see a single indexing term or a list of indexing terms used in a document informative content representation, but often he cannot, at the moment of formulation of the query, effectively grasp the structure of the different indexing terms related to an indexing term of interest. A facility of this kind, if available, can prove very useful, but it is not sufficient to really inform the user of the structural organisation of the indexing terms; in fact this facility is normally available only in a non-integrated fashion and the user needs to know an indexing term beforehand in order to begin wandering through the semantic structure. With the above-mentioned research and implementation considerations in mind, we started the work reported in this paper with the following underlying motivations: to give the final user the possibility to actively browse through the indexing term structure in order to acquire a proper understanding of the semantic context in which the _ of each term has been defined by the indexers, to allow the user to see those documents related to possibly

Annotations in Digital Libraries and Collaboratories – Facets, Models and Usage

Abstract 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.

A hypertext environment for interacting with large textual databases

This paper presents the results of our study regarding the different facets and ways of using annotations in both digital libraries and collaboratories. This study represents an innovative attempt at gathering methodological tools and synergies from both fields in order to effectively define a comprehensive model for annotations. Thus we propose a conceptual model for annotations in order to develop an annotation service that can be plugged into digital libraries and collaboratories. Finally, starting from our model, we introduce a search strategy for exploiting annotations in order to search and retrieve relevant documents for a user query.

Automatic authoring and construction of hypermedia for information retrieval

Abstract This paper presents a design and implementation project based on a two-level conceptual architecture for the construction of a hypertext environment for interacting with large textual databases. The conceptual architecture has been proposed to be used for a semantic representation of the informative content of a collection of documents and for the organisation of the document collection itself. The hypertext environment is based on a set of functions that permits one to exploit the potential capabilities of the two-level architecture. Those functions are presented in detail. The paper reports some results of a more general project whose final goal is the definition of a new model for information retrieval: a model with information retrieval capabilities embedded within a hypertext environment. Finally, an outline is presented of the characteristics of a prototype, named HYPERLINE, of the hypertext environment. This prototype has been developed by the Information Retrieval Service of the European Space Agency (ESA-IRS).

Design and implementation of a tool for the automatic construction of hypertexts for information retrieval

This paper describes the complete process and a tool for the automatic construction of a multimedia hypertext starting from a large collection of multimedia documents. Through the use of an authoring methodology, the document collection is automatically authored, and the result is a multimedia hypertext, also called a hypermedia, written in hypertext mark-up language (HTML), almost a standard among hypermedia mark-up languages. The resulting hypermedia can be browsed and queried with Mosaic, an interface developed in the framework of the World Wide Web Project. In particular, the set of methods and techniques used for the automatic construction of hypermedia is described in this paper, and their relevance in the context of multimedia information retrieval is highlighted.

Annotations as context for searching documents

Abstract The paper describes the design and implementation of TACHIR, a tool for the automatic construction of hypertexts for Information Retrieval. Through the use of an authoring methodology employing a set of well known Information Retrieval techniques, TACHIR automatically builds up a hypertext from a document collection. The structure of the hypertext reflects a three level conceptual model that has proved to be quite effective for Information Retrieval. Using this model it is possible to navigate among documents, index terms, and concepts using automatically determined links. The hypertext is implemented using the HTML hypertext mark up language, the mark up language of the World Wide Web project. It can be distributed on different sites and different machines over the Internet, and it can be navigated using any of the interfaces developed in the framework World Wide Web project, for example NetScape .