Abstract
Multimedia databases are extending the scope of traditional databases to handle the complex structure of multimedia objects. Models for multimedia information must include representations for the structure and content of several media in a form that allows flexibility in retrieval. Content-based retrieval is the main motivation behind recent research in multimedia databases. The task of searching in video and audio content is made hard by the nature of audiovisual data where, unlike text, there is no direct syntactic channel between the object and its meaning [1]-[3]. We propose a model for multimedia content storage and retrieval accounting for both context and content information and taking advantage of their dependencies for effective retrieval. We then describe a prototype multimedia database with a retrieval interface. It has been used as a workbench for testing the representation model and integrating tools for feature extraction, information interchange and retrieval. The workbench allows an easy inclusion of new tools for content analysis and new methods for context- and content-based retrieval while offering storage and access for both the actual digital content and its metadata.

Abstract
Wikis are popular tools commonly used to support distributed collaborative work. Wikis can be seen as virtual scrap-books that anyone can edit without having any specific technical know-how. The Wikipedia is a flagship example of a real-word application of wikis. Due to the large scale of Wikipedia it's difficult to easily grasp much of the information that is stored in this wiki. We address one particular aspect of this issue by looking at the revision history of each article. Plotting the revision activity in a timeline we expose the complete article's history in a easily understandable format. We present WIKICHANGES, a web-based application designed to plot an article's revision timeline in real time. WIKICHANGES also includes a web browser extension that incorporates activity sparklines in the real Wikipedia. Finally, we introduce a revisions summarization task that addresses the need to understand what occurred during a given set of revisions. We present a first approach to this task using tag clouds to present the revisions made. © 2008 ACM.

Abstract
The INESC Porto group has participated in the search task (automatic and interactive). Our approach combines high-level features (the 39 con- cepts of the LSCOM-Lite set) with low-level features. We use a large set of low-level features with the intention of analysing as many facets as possible of each shot. The aggregation of large feature sets can be time consuming as it needs to be done at query time. We have developed the BitMatrix indexing method to speed up the search process. For each shot, binary signatures in the form of bit sequences are obtained in an on-line process. At query time, the query bit signature is compared to each of the shots signatures. The automatic run performs above the median, in spite of not using any classifier or any other knowledge sources except the translation of the query into LSCOM-Lite concepts.

Abstract
The paper presents a multimedia database model accounting for the representation of documents, collections and the associated metadata. Appropriate structures are provided for descriptive metadata and for metadata resulting from automatic content analysis. The model is based on the identification and unification of the main concepts in the archival standards and the audiovisual area. The main features of the model, designed to support multimedia database applications, axe the integration of descriptive and content analysis metadata, the association of metadata to collections as well as to items, the extensibility with respect to the inclusion of new descriptors and the support to several retrieval modes. The MetaMedia application development platform, based on the model, has been used to support the construction of a historic documentation collection where a common web interface provides collection administrators, metadata creators and visitors a multi-faceted view of the repository.

Abstract
The web is currently the information searching and browsing environment of choice for scholars and lay users alike. The goal of most cultural heritage applications is to interest a large audience, and therefore web interfaces are being developed even when part of their functionality is not offered to the general public. We present a web-based interface for managing, browsing and searching a repository of historic documents. The documents pertain to a region which has been an important regional power in medieval times and their originals are under the custody of the Portuguese national archives. The challenges of the project came from its requisites in three aspects: rigorous archival description, the incorporation of document analysis and a flexible search interface. The system is an instance of a multimedia database framework providing both browse and retrieval functionalities to end users and configuration and content management services to the collection administrators.

Abstract
Cultural heritage documents are often subject to digitization processes resulting in image material, even for textual contents. It is therefore common, in collections of valuable documents, to have descriptive information generated by the institutions, along with digitized images, transcriptions created by scholars, translations and even miscellaneous annotations. To offer a faceted access to the collection it is necessary to explore these diverse materials, integrate them according to a model that accounts for both metadata and the content and provide a comprehensive retrieval environment. In this work we have applied the MetaMedia multimedia database framework to a collection of ancient documents, processed the documents in their descriptive, textual, and image content and produced a browsing and searching system. The main challenges are the integrated management of metadata and content, the indexing of the image content, and the design of the browsing and searching interface where various views on the data are kept together. Copyright (C) 2009 Catalin Calistru et al.