Introduction to Special Issue on The Use of Contextin Multimedia Information Systems

K. SELCUK CANDAN

Arizona State University

AUGUSTO CELENTANO

Ca’ Foscari University of Venice

and

WOLFGANG KLAS

University of Vienna

This special issue contains extended versions of the three best papers presented at the 11th Interna-tional Workshop on Multimedia Information Systems (MIS) held between 19 and 21 September 2005in Sorrento, Italy.

The primary goal of the MIS workshops is to report on cutting edge research across all areas ofmultimedia systems so that researchers in different areas of multimedia information systems get toknow, and are influenced by, other research directions. MIS workshops bring together investigatorsfrom academia, industry, and government labs to address research problems in various areas relatedto multimedia information systems. The areas of focus of MIS include databases, knowledgebases, op-erating systems, and networking to support development of effective and efficient multimedia systems.Despite the diversity of technical challenges underlying multimedia system design and development,we note that a common requirement in any multimedia information system is to be able to select, direct,and focus its processing appropriately (i.e., as necessitated by the task and context) to transform rawmedia data into useful information.

Current information systems make significant use of multimedia data. A key issue with multimediainformation systems is that their behavior cannot be generic, but must be tailored to several parametersthat describe the user situation in its many facets, and that collectively represent what is called a con-text. To obtain a context-aware behavior, context-oriented design is required. Context has been studiedin application development and user computer interaction. Initially linked to the concepts of space andtime of action, then extended to include adaptation of the information presentation to a variety of de-vices, it has evolved to include any information about the environment in which a system acts that caninfluence its operation [Dey 2001; Schmidt et al. 1999]. In information systems the context is used tosupplement the user operations with implicit information about the user state. In multimedia infor-mation systems this role is even grater, due to the many facets of multimedia data, which require asystem to behave differently not only in the way the information is presented, but also in selecting theright information to deliver. Context is therefore a “hidden partner” of the user, silently feeding part ofinformation, or silently tuning some parameters that allow the user to receive the needed informationand service in the right place, in the right way, and with an adequate interaction effort [Dey 2001;Schmidt et al. 1999; Weiser and Brown 1997].

Contextual adaptation is necessary at multiple levels: first of all, at the lowest level, multimedia datacan be stored and transmitted at different precision scales depending on the available resources andapplication semantics. Secondly, multimedia data can be indexed and retrieved with varying accuracy

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levels depending on the time available for processing users’ queries and the precision required by theusers. Synchronization and presentation of the multimedia data can also reflect the context (includ-ing the hardware and software availabilities as well as the user preferences). At a higher level, themultimedia data presented to the user need to be consistent with the user’s potentially evolving objec-tives. Therefore, besides more traditional content management technologies, new challenges regardingthe gathering of media from sensing devices in the environmental context and the task, informedprocessing of media based on the current task and resources, and making the results available tothe user in the most suitable form based on the capabilities and preferences of the user, are emerg-ing. Thus, these challenges in mind, MIS 2005 concentrated on specific research issues related to thespecification, management, and interpretation of the contextual knowledge in multimedia informationsystems.

1. HOW CONTEXT IS LEVERAGED IN MULTIMEDIA INFORMATION SYSTEMS

The three articles included in this special issue exemplify three important dimensions (domain de-scription, adaptation of data to different tasks, and effective interface design) in which the knowledgeof context can be used in multimedia system design. They are, however, only a small sample of thecomplementary dimensions discussed for leveraging context in multimedia information systems. Inthis section, we use examples from MIS2005 to provide an overview of additional uses of context inmultimedia information systems.

The Use of Context in Media Annotation. Chin et al. [2005] highlight the difficulties in annotatingmultimedia data using only visual features. In particular, the authors point out that the current auto-matic annotation techniques result in too many irrelevant keywords. In this article, the authors showthat semantic contextual information, available in the form of ontologies (such as WordNet), can beused for improving the annotation accuracy.

The Use of Context in Query Disambiguation. In Albanese et al. [2005], the authors highlight thatimproving the effectiveness of information retrieval by disambiguating a given query requires a deeperunderstanding of the keywords, not immediately obtainable from the query itself. Thus, authors proposemechanisms for learning the context of a given query through explicit user feedback. They also proposemechanisms for leveraging the knowledge about the query topic for pruning the results presented tothe user.

The Use of Context in Assisted Navigation within Complex Data. Antonelli and Sapino [2005] point tothe importance of providing cues to the individuals who are blind, for assisting them while navigatingthrough complex web content. In particular, they show that one can effectively leverage knowledge abouta particular domain (e.g., educational web site) and the structure of the data (e.g., discussion boards)in developing rule-based systems for classifying and annotating content for navigational support.

The Use of Context for Enhanced Navigational Experience. The need for use of contextual informationin navigation is also highlighted in Pittarello [2005]. In this article, the author focuses on the challengesinvolved in designing 3D virtual environments, such as art exhibitions or e-learning systems, where itis important to understand the user’s experience for providing the most relevant data to the user duringnavigation. For this purpose, the author presents an architecture that considers the influence of context(including location, user profile, user history, time, device, and network) in selecting and presenting theappropriate media data.

The Use of Context in Adapting Multimedia Delivery to Presentation Devices. Muldoon et al. [2005]note that there are wide ranges of differences among the processing capabilities and screen resolutionof mobile devices for multimedia applications. Thus, with the goal of reducing the development costs ofmobile multimedia applications, authors develop a generic language for interface development (GLIDE).A set of specifications using the proposed language acts as a semantic model of the interface and provides

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an abstract framework that dynamically reconfigures itself to adapt to user interactions and remainsconsistent across a range of ubiquitous devices.

2. THE ARTICLES INCLUDED IN THIS SPECIAL ISSUE

The three articles presented here focus on the specific challenges associated with the retrieval andpresentation of media in diverse and heterogeneous contexts. They are selected to be included in thespecial issue for their technical contribution as well as for their coverage of the three main dimensionsof the use of context in multimedia information systems: (a) description of domain-specific context, (b)data adaptation based on context, and (c) use of context in developing effective visualization schemes.

2.1 Domain Specific Ontologies for Describing Context

The first article, “A Semantic Web Ontology for Context-based Classification and Retrieval of MusicResources” by Ferrara et al. focuses on the problem of classification of music resources with respect tothe notion of musical genre. The authors highlight that a major challenge in classification is the factthat there is no consensus about the genre taxonomy. To address this challenge, the authors define ananalytical context through four dimensions of the music resource context (melody, rhythm, harmony, andensemble) and they leverage this context in developing an ontology, MX-Onto, for genre classificationof music resources.

2.2 Providing Multiple Points of Views of the Data Based on Context

In “Handling Multiple Points of Views in a Multimedia Data Warehouse”, Anne-Muriel Arigon and hercolleagues focus on multimedia data representation for data warehousing and OLAP applications. Theauthors point to the fact that in different application domains it is essential to characterize data fromvarious points of views, depending for instance on the context described by user profiles, preferences,and level of expertise. Based on this observation, the authors introduce a new multidimensional model,which enables users to obtain different points of view on the available data, appropriate for differentdata analysis contexts.

2.3 The Use of Context in Perception and Visualization

In the last article included in this special issue, “Modeling Context in Haptic Perception, Rendering,and Visualization,” Kanav Kahol and his colleagues focus on the challenges associated with developinghaptic user interfaces, with the applications in diverse fields, including telesurgery and teleoperation aswell as assistive and rehabilitative technologies for individuals with sensory and cognitive impediments.The techniques presented in this article model and leverage contextual clues about material, shape,size, texture, and weight configurations of objects as well as the spatial context in which motor strategyof haptic exploration. Kanav and his colleagues show that such contextual cues provide significantimprovements in accuracy and efficiency in augmented reality environments.

ACKNOWLEDGMENTS

We would like to thank all the authors and reviewers for their contributions to the special issue. Wewould also like to thank the editors of ACM TOMCCAP for publishing this special issue.

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