Chapter 6: Concluding Remarks

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Users of future distributed Multimedia Database Management Systems (MMDBMSs) will be heavily mobile and require ubiquitous access to, and satisfactory presentation of, multimedia data, regardless of the actual connectivity and the specific presentation terminal they are currently using. Moreover, users will expect to find information and multimedia content faster and more easily (e.g., query by semantics), and will interact with the content much more intensively than they do today. Finally, users will expect to make avail of more sophisticated multimedia services, such as location-aware services, multimedia billing services, or advanced observation services, that go beyond the simple database searches (e.g., query by color similarity) of today.

This concluding chapter is organized as follows: Section 6.1 summarizes the major contributions of the book. We then focus on semantics in multimedia databases (Section 6.2). The challenge of mobility for MMDBMSs is discussed in Section 6.3. Finally, Section 6.4 draws on the idea of multimedia middleware to bridge the gap between multimedia applications and the network.

6.1 Summary of the Book

The book introduced distributed multimedia database technologies. Its contents were compiled from review of relevant literature, assessment of ongoing projects, and discussion with researchers in the field.

It has been shown in Chapter 4 that broadly used content-based indexing and retrieval methods based on primitive features (such as color, texture, and shape) that can be extracted from the data themselves are not sufficient to meet the requirements of widely used multimedia applications for semantic multimedia indexing and retrieval. However, with the newly emerging MPEG-7 standard, uniform description schemes have been proposed that allow one to build an integrated indexing and retrieval system both for primitive features and semantics. This is why a detailed description of MPEG-7, including a guide on how to build MPEG-7 documents, was given in Chapter 2. Building on the concepts and examples introduced in Chapter 2, we showed in Chapter 4 how a MPEG-7-supported MMDBMS can be realized.

The book was not limited to indexing but also discussed techniques for processing and optimizing queries and for storing, accessing, and finally delivering media data as well as their respective metadata. We introduced the new ISO/IEC SQL/MM standard for querying multimedia data in object-relational databases and compared the data models beyond SQL/MM with that of MPEG-7. A useful collaboration of SQL and MPEG-7 in a MMDBMS was presented that has been applied, for instance, in Kosch. ^[1]

The distributive aspect of an MMDBMS has so far been neglected, and the research was mostly conducted in isolation from other systems' issues. Therefore, one major contribution of this book was the linking of distributed processing issues to processing and modeling issues in MMDBMSs. We focused here on the effect of MPEG-21, the newly emerging multimedia framework standard, and gave a detailed introduction in Chapter 3. We discussed the effect of MPEG-21 on distributed MMDBMSs with respect to its integration capacity for related coding and metadata standards in Chapter 5. The cooperation of MPEG-21 and MMDBMSs naturally leads to a distributed multimedia system, which enables the augmented use (by rights, intellectual properties, etc.) of multimedia resources across a wide range of networks, devices, and communities.

^[1]Kosch, H., MPEG-7 and multimedia database systems, SIGMOD Rec., 31, June 2002.

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