Roelof van Zwol

Multi-Dimensional Scattered Ranking Methods for Geographic Information Retrieval*

Geographic Information Retrieval is concerned with retrieving documents in response to a spatially related query. This paper addresses the ranking of documents by both textual and spatial relevance. To this end, we introduce multi-dimensional scattered ranking, where textually and spatially similar documents are ranked spread in the list, instead of consecutively. The effect of this is that documents close together in the ranked list have less redundant information. We present various ranking methods of this type, efficient algorithms to implement them, and experiments to show the outcome of the methods.

The webspace method: on the integration of database technology with multimedia retrieval

Large collections of documents containing various types of multimedia, are made available to theWWW. Unfortunately, due to the un-structuredness of Internet environments it is hard to find specific information when one is looking for it. Search engines available can only rely their results on information retrieval techniques and most of the time they lack the desired power in query formulation. Modelling data on the web, as if it was designed for use within databases, should provide us with the necessary basis for enhancing this query formulation. This of course requires special care for dealing with the included multimedia data and the semi-structured aspects of data on the web.Modelling the entire web would be too ambitious, therefore we focus on a more feasible environment, like the intranet, where one can find large collections of related data. With the webspace method we have already shown how to deal with the various aspects of semi-structured data in large collections of related documents. In this paper we focus on the integration of our webspace method for concept-based search with content -based multimedia information retrieval (IR). A webspace consists of two levels. At the document level, a webspace is considered to be a collection of related documents. At the semantical level, concepts are defined to be used in the documents at the document level. By modelling these concepts using a webspace schema a semantical level of abstraction is gained. This supplies the necessary platform for querying data available within a specific webspace. For the integration with content-based information retrieval an existing IR model is adopted. We will discuss how this is used in the context of Mirror, a Multimedia DBMS, and how this framework is used for the integration with the webspace method for concept-based search.

Bricks: the building blocks to tackle query formulation in structured document retrieval

Structured document retrieval focusses on the retrieval of relevant document fragments for a given information need that contains both structural and textual aspects. We focus here on the theory behind Bricks, a visual query formulation technique for structured document retrieval that aims at reducing the complexity of the query formulation process and required knowledge of the underlying document structure for the user, while maintaining full expression power, as offered by the NEXI query language for XML retrieval. In addition, we present the outcomes of a large scale usability experiment, which compared Bricks to a keyword-based and a NEXI-based interface. The results show that participants were more successful at completing a search assignments using Bricks. Furthermore, we observed that the participants were also able to successfully complete complex search assignments significantly faster, when using the Bricks interface.

INEX 2005 multimedia track

This paper reports on the activities of the INEX 2005 Multimedia track. The track was successful in realizing its objective to provide a pilot evaluation platform for the evaluation of retrieval strategies for XML-based multimedia documents. In this first exploratory year the focus of the evaluation experiment was to test approaches for the retrieval of XML fragments using a combination of content-based text and image retrieval techniques. The track is set to continue at INEX 2006.

Road collapse in Magnum

This paper describes the implementation of a triangulation based collapse algorithm in the general-purpose object oriented DBMS Magnum. The contribution of the paper is twofold. First, we show that true integration of complex spatial functionality in a DBMS can be achieved. Second, we worked out a collapse algorithm to be used in the complex area of map generalization.

Multimedia strategies for B 3 -SDR, based on principal component analysis

In this article an XML-driven approach for multimedia information retrieval is presented and evaluated, which uses principal component analysis to derive a composite ranking for a set of XML elements that have a multimedia character. The multimedia strategies that implement the PCA module on top of the B3-SDR system allow for the integration of image retrieval with the already present text retrieval modules. Three different strategies are defined. The first strategy implements annotation-based image retrieval, which uses the caption of an image to find related images using a keyword-based search. The second component enables content-based multimedia retrieval by using PCA to derive a composite ranking, which reflects the combined relevance for text and images that are present within an XML element. A simple content-based image retrieval system is build for this purpose, which uses ‘query by example’. The last strategy allows for a bidirectional combination of the first two strategies, where the content-based image retrieval component benefits from the additional images retrieved by the annotation-based search, and vice versa. The multimedia strategies are evaluated within the INEX 2005 multimedia track, where based on the Lonelyplanet Worldguide and a set of related topics the retrieval performance is measured in terms of recall and precision. The outcome of the experiment shows that the multimedia strategies have a positive influence on the retrieval performance when compared to the text-based XML retrieval system. However, the PCA component did not yet fully live up to its expectation, which is probably due to the poor performance of the ad hoc build image retrieval system that is used for the experiment.

B 3 -SDR and effective use of structural hints

The focus in this article is on the use of structural hints to increase the retrieval performance of models for structured document retrieval. Based on an effective model for structured document retrieval for ‘content only’ queries, two extensions are defined that allow the retrieval model to include structural hints provided by the user into the retrieval process. The underlying hypothesis states that if the user is capable of providing structural clues, besides the content-based criteria of his/her information need, the retrieval performance can be increased. To test this hypothesis the two extensions are evaluated using a selection of the retrieval tasks defined for the INEX 2005 Ad-hoc track.

Google’s “I’m Feeling Lucky”, Truly a Gamble?

With huge quantities of multimedia information becoming available on the Internet everyday, our foremost mechanisms to find information still rely on text-based retrieval systems with their keyword-based query interfaces. However little to nothing is known about the retrieval performance and/or the quality of the user interface of these search engines.

The utrecht blend : Basic ingredients for an XML retrieval system

Exploiting the structure of a document allows for more powerful information retrieval techniques. In this article a basic approach is discussed for the retrieval of XML document fragments. Based on a vector-space model for text retrieval we aim at investigating various strategies that influence the retrieval performance of an XML-based IR system.

Using Webspaces to Model Document Collections on the Web

Due to the unstructured character of data on the web it is hard to find specific information when surfing over the web. Search engines can only rely their results on IR techniques available, and most of the time they lack the desired power in query formulation. Modelling data on the web, as if it was designed for use within databases, provides us with the necessary basis for enhancing the query formulation. This requires special care for dealing with the included multimedia data and the semi-structured aspects of the data on the web. Modelling the entire web would be too ambitious, therefore we focus on a more feasible environment, like the intranet, where one can find large collections of related data. This article describes the webspace method for modelling the content of a collection of a domain specific documents, and offers a solution for the above mentioned problems.