Multimedia Software Engineering (MSE) is a new frontier for both Software Engineering (SE) and Visual Languages (VL). In fact multimedia software engineering can be considered as the discipline for systematic specification, design, substitution and verification of visual patterns. Visual Languages contribute to MSE such concepts as: Visual notation for software specification, design and verification flow charts, ER diagrams, Petri Nets, UML visualization, visual programming languages etc. Multimedia Software Engineering and Software Engineering are like two sides of the same coin. On the one hand we can apply software engineering principles to the design of multimedia systems. On the other hand we can apply multimedia technologies to the software engineering practice. In this paper we concentrate on the first of these possibilities. One of the promising application areas for Multimedia Software Engineering is Distance Learning. One aim of this paper is to demonstrate how it is possible to design and to implement complex multimedia software systems for Distance Learning using a Teleaction Object transformer based on XML technology applying a Component-Based Multimedia Software Engineering approach. The paper shows a complete process of dataflow transformation that represents TAO in different ways (text, TAOML, etc.) and at different levels of abstraction. A component-based tool architecture is also discussed.The use of an XML-based approach in the Distance Learning field has other advantages as well. It facilitates reuse of the teaching resources by using metadata. Standards for representing multimedia distance learning materials are currently evolving. Such standards are necessary in order to allow a representation which is independent of hardware and software platforms so that this material can be examined, for example, in a web browser or so that it may be reused.

Current distance learning is mostly based on Web technologies. However, course materials announced as Web documents do not have a normalized structure. It is difficult for students to realize where they are in a Web navigation graph. On the other hand, a text book has a fixed structure, such as the hierarchy of chapters and the index. A text book reader knows how to start searching for information with the common structure of books in his/her mind. If distance learning course materials are organized in one or two patterns, it would be easier for an individual student to follow. We investigate this approach, and propose a system for Web course designs with patterns. The system also serves as a front end module of a Web learning environment which provides automatic assessment of student performance.

Multimedia systems incorporating hyperlinks and user interaction can be prototyped using TAOML, an extension of HTML. TAOML is used to define a Teleaction Object (TAO) which is a multimedia object with associated hypergraph structure and knowledge structure The hypergraph structure supports the effective presentation and efficient communication of multimedia information. In this paper, a formal specification methodology for TAOs using Symbol Relation (SR) grammars is described. An attributed SR grammar is then introduced in order to associate knowledge with the TAO. The limitations to achieve an efficient parser are given. The grammatical formalism allows for validation and verification of the system specification. This methodology provides a principled approach to specify, verify, validate and prototype multimedia applications.

Data flow diagrams are an important design aid in system development. CASE tools allow data flow diagram construction and modification to be automated. Decomposition is the top-down development of a data flow diagram starting with the system inputs and the system outputs. Decomposition may also be automated, resulting in an interactive process for data flow diagram design. Adler (1988) described an algebra for the decomposition of data flow diagrams. A set of quality measures was also described. The authors show that these quality measures do not correspond to the intuitive notion of a good decomposition. A new set of criteria is proposed which does correspond to the intuitive notion of a good decomposition. The use Adler's algebra leads to an inefficient decomposition process, as well as one which is not guaranteed to find a good decomposition. The authors give an efficient algorithm which gives a good decomposition.>

Several iconic indexes for representing three-dimensional scenes are presented. The approach extends previous work in iconic indexing of two-dimensional scenes in a unified manner. Good characteristics for iconic indexes are also pointed out. OPP2 and OPP3, two-dimensional iconic indexes for three-dimensional scenes, are introduced. The problem of ambiguity in the OPP2 and OPP3 representations of three-dimensional scenes is studied in detail and a class of images for which they are unambiguous is identified. The Genstring, a linear iconic index which can be used to represent two-, three-, or higher-dimensional scenes, is introduced. It provides a compact, unambiguous representation of a three-dimensional scene. The Genstring takes advantage of previous work, thus providing fast pattern matching for higher-dimensional scenes. In fact, the pattern matching algorithm given for k-dimensional scenes is as fast as that previously given for two-dimensional scenes.>

A prototype intelligent image database system (IIDS) that is based on a novel pictorial data structure is presented. This prototype system supports spatial reasoning, flexible image information retrieval, visualization, and traditional image database operations. A pictorial data structure, based on 2-D strings, provides an efficient means for iconic indexing in image database systems and spatial reasoning. The modular design of IIDS facilitates its implementation. Further extensions of the prototype system are discussed.>