Newsletter Issue 3

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Information Access and Personalization

The Information Access and Personalization cluster enters the second period of the project with a new, exciting research agenda. Georgia Koutrika outlines for us the new research activities envisaged in the new phase.
  

The New Research Agenda for IAP
  

Introduction
  

The Information Access and Personalization cluster enters the second period of the project with a new, exciting research agenda. This agenda has come as a product of the efforts of the cluster so far as well as a logical continuation of them. For this reason, it comprises a list of vital research topics with a fair distribution of interest and effort among the major areas of the cluster's interests. In addition, it provides a strong incentive for collaboration among researchers with different background and interests in order to solve new problems that require expertise from different fields.
   

IAP's Strategic Goals
  

This agenda represents the combined effect of the cluster's past efforts. These have been planned in line with the following strategic goals:

1. Construction of a common, comprehensive framework for information access and personalization approaches. Towards this end, a set of comprehensive surveys and reports have been generated. These provide a broad coverage of the general areas of interest to the cluster, and describe problems, existing models and approaches.
2. Promotion of knowledge about available practices in the fields of information access and personalization in digital libraries. To further this objective, several information-sharing and dissemination activities have taken place.
3. Initiation of research on new information access and personalization models and methodologies. This was made possible through the afore-mentioned activities and the researchers' exchange programme.

All these activities have led to the identification of major research trends and significant obstacles in the fields of information access and personalization as well as the establishment of cooperation between researchers and of several research proposals. In addition, they have provided the proper basis for the new objectives.
  

Phase Two
  

During the second phase, the Information Access and Personalization cluster will build on and continue the work performed during the first period and will pursue the following strategic goals:

1. Substantial support of cooperation between individual research groups initiated during the first phase of the project.
2. Research on new models and methodologies in order to eliminate inefficiencies in existing ones.
3. Development of toolkits and systems for purposes of re-use and demonstration of proposed methods and models.

IAP Research Agenda
  

For the second phase of DELOS Project, we have drawn three basic lines of research:

• Advanced Information Access Methods
• P2P resource-sharing for Digital Libraries
• User Context Modelling

Along these lines, five new activities have been planned overall. These, along with those activities continuing from the first period of the project’s lifetime, constitute the new research agenda of the IAP cluster. In what follows, I will try to give an overview of the aforementioned research directions.
  

1. Advanced Information Access Methods
  

The importance of this topic is justified by the ever-growing volume of multimedia objects in digital libraries. Added to this is the critical role multimedia plays in the improvement of a user's experience when accessing a Digital Library. Therefore, effective and efficient information access of multimedia content becomes increasingly more important. In particular, the main challenge here is as follows:

• Query processing for non-alphanumeric data (e.g. similarity search in large collections of media objects) is often conducted by means of some distance metric that computes a score quantifying the similarity of two objects. Unfortunately, distance metrics fail to answer queries efficiently as soon as the dimensions of the feature vectors exceed a certain "usability threshold".

The main issues to be investigated include the following:

• Development of novel indexing and query processing algorithms: The goal pursued is indexing and query processing approaches that :
  (i) efficiently support several types of queries over multimedia, such as nearest neighbour, range, and ranking queries,
  (ii) operate on any kind of multimedia data, and
  (iii) are generic.
• Design of distributed access methods for similarity search: The goal is to study new distributed storage structures for similarity search of data by exploiting the P2P paradigm.
• Similarity search approaches in digital library applications exploiting XML encoded metadata: Emerging metadata standards (e.g. MPEG-7) encode metadata (including audio/visual features) with XML. In this respect, the objective is to investigate techniques for efficient processing of combined exact and similarity match queries on XML-encoded metadata to support complex search capabilities in multimedia digital libraries.

2. P2P Resource-sharing for Digital Libraries
  

The peer-to-peer (P2P) paradigm is an intriguing approach for coping with dynamically evolving federations of loosely coupled digital libraries. The large scale and high dynamics of a P2P system poses very challenging issues as far as information access is concerned:

• A P2P network comprises Digital Library (DL) nodes, which should be autonomous, and, ideally, should have no restrictions on how to organize their data and what kind of query capabilities to offer.
• DL services should support decentralized sharing and management of data through a P2P network of DL nodes. In such a network, a DL node must be able to provide data to other DL nodes and, at the same time, to have access to data of other DL nodes, while retaining its own autonomy by making local decisions.
• In addition to the libraries, user agents with powerful personalized tools may participate as peers. User peers should also remain autonomous and participate in the P2P system and collaborate on behalf of user requests at their discretion. In a typical scenario, a user peer would utilize its local profile to compile an information demand and issue queries to the library peers that are most suitable for the given demand.

Such a P2P system promises unlimited scalability, robustness to failures, fluctuation, and load dynamics, and also much reduced vulnerability to attacks and information manipulation.
  

The main issues that will be investigated include:

• Query reformulation in P2P DLs: To answer a query in a P2P setting, queries are reformulated to match the schemas of the data sources. To perform this reformulation task the key issue is mapping rules. Ideally, the assumption of a single global schema should not have to be a prerequisite in a P2P Digital Library. The objective is to investigate the foundations of query reformulation using mappings in P2P DLs, where the query language will be either XML-based or RDF/S-based.
• Query roaming in P2P DLs: The 'roaming' facility allows a user to enjoy uninterrupted communication (through a mobile network or through the Internet) from anywhere in the entire network coverage space. During query roaming, planning and execution must be interleaved, since the precise evaluation steps of the computation and the participating peers cannot be foreseen in advance. Furthermore, plans may have to be revised at runtime and contingency choices made, e.g., when a peer involved in the computation suddenly leaves the system. The objective is to investigate routing, planning, and processing of declarative queries in order to support roaming in P2P DLs.
• Database selection: While an issue that has been intensively studied in the literature on distributed IR and meta-search engines, the large scale and high dynamics of a P2P system pose greater challenges, including issues such as the dissemination, maintenance, and effective use of statistical summary information about the peers' information content. The objective here is to investigate opportunities for advanced personalization of information selection and query execution based on users' access patterns, query logs, and further user-behaviour information kept in peers.

3. User Context Modelling
  

The interpretation and suitability of data increasingly depends on changing conditions, like for example the current position of the user or the media he is using (laptop, mobile, PDA, etc.), and on user characteristics, e.g. preferences. All these parameters constitute the user's context which should be taken into account during information access in order better to serve the user. Towards this direction, it is essential that information providers specify the context under which information becomes relevant. Conversely, information users can specify their (context-dependent or context-free) preferences as well as their current context when requesting for data.
  

Towards the enhancement of the personalization capabilities of DL systems, the following issues will be investigated:

• Foundations for a context-aware database system: It is important to investigate how the notion of context can be incorporated into data stored in DLs of relational form. The investigation will be done at two levels: an abstract and an applied one. Initially the focus will be on laying the foundations for a context-aware database management system, and then the task will attempt to define a uniform mechanism for personalized access to Digital Libraries.
• Management of user preferences: Towards the same end, enrichment of the DL information organization and retrieval services with preference capabilities for supporting personalized services will be studied. Such services include query personalization (i.e. enhancing a query by incorporating into it user-specific preferences), user notification (notifying a user when an 'event' of interest happens), and document customization (allowing the user to compose documents that will be created by the system).

Concluding Remarks
  

The outcomes from the efforts of the Information Access and Personalization cluster so far have served to underline the significance of the research directions selected. Furthermore, the research agenda of the IAP cluster retains two additional and unique features:

• It achieves a fair distribution of interest and work among the major dimensions of the cluster's work, namely Information Access (interaction with a single information provider), Information Integration (interaction with multiple information providers) and Personalization (customization of information and interaction to the user)
• It provides incentives for collaboration among researchers of differing backgrounds and interests so as to solve emerging problems which require expertise from different fields

With this research agenda before us, the second period of the project for the Information Access and Personalization cluster promises to be both challenging and exciting.
  

Author Details
  

Georgia Koutrika
University of Athens
Email:
Tel: +30 210 727 5242
Fax: +30 210 727 5214

  

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Publication date: June 2005
File last modified: Monday, 22-May-2006

The Delos Newsletter is published by the Delos Network of Excellence
and is edited by Richard Waller of UKOLN, University of Bath, UK.

   

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