EG1993Barcelona, Spainhttps://diglib.eg.org:443/handle/10.2312/2012024-03-28T20:42:34Z2024-03-28T20:42:34ZAn Object Model for Multimedia ProgrammingArbab, F.Herman, I.Reynolds, G.J.https://diglib.eg.org:443/handle/10.2312/68702022-03-28T11:55:21Z1993-01-01T00:00:00ZAn Object Model for Multimedia Programming
Arbab, F.; Herman, I.; Reynolds, G.J.
The development of multimedia applications is a complex task. Much of this complexity stems from requirements associated with programming multiple media objects and the control of dependences and inter-relationships between these media objects and the user(s). It is clearly necessary to have a basic framework on which to build multimedia applications in the face of such complexities. Such a conceptual model is what we have called an object model and it is the main subject of this paper. The MADE object model represents a novel approach to multimedia application programming that is founded on the two principal concepts of active objects and delegation. Although these concepts are not novel in themselves, we believe that their combined use in a multimedia development environment represents a substantial enhancement to more traditional approaches to programming in this area.
1993-01-01T00:00:00ZStorage Support for Multidimensional Discrete Data in Multimedia DatabasesFurtado, PaulaTeixeira, Jose Carloshttps://diglib.eg.org:443/handle/10.2312/68692022-03-28T11:55:17Z1993-01-01T00:00:00ZStorage Support for Multidimensional Discrete Data in Multimedia Databases
Furtado, Paula; Teixeira, Jose Carlos
Multidimensional discrete data (MDD) is enormously important for multimedia applications since diverse types of such data are used simultaneously by any multimedia application. However, multidimensional discrete data is not adequately supported by most existing database systems.In this paper we discuss the major management requirements imposed by such data on multimedia database management systems both at the conceptual level and at the internal level. At the internal level, the spatial structure of the data must also be preserved and special emphasis must be given to the efficient spatial access to subrectangles of very large data of arbitrary dimensionality.Our major contribution is the presentation of a Storage Manager for this kind of data which preserves the spatial nature of the data at the internal level of the database management system and provides efficient spatial access. This Storage Manager is based on an innovative combination of the subdivision of data in multidimensional tiles and of a spatial index to access those tiles. Furthermore, it supports advanced registration data.The lower level modules of the Storage Manager are responsible for the access to the data stored in secondary storage. The implementation of these modules can rely on any secondary storage access system to access data on disk. The Storage Manager was implemented using the functionality of a relational database system. The implementation of this relational Storage Manager is presented.
1993-01-01T00:00:00ZUsing Multimedia to Support Cooperative EditingSantos, A.Tritsch, B.https://diglib.eg.org:443/handle/10.2312/68682022-03-28T11:55:17Z1993-01-01T00:00:00ZUsing Multimedia to Support Cooperative Editing
Santos, A.; Tritsch, B.
By Cooperative Editing we mean the coordinated manipulation of information by a group of authors. During the editing process the (co-)authors need to communicate their ideas, drafts and constraints (remotely or face-to-face) until a final version of the information is achieved. For the different phases of this process - discussion of ideas, editing, cross-checking - different media or media integration are adequate. Furthermore, analysing the transition from individual work to group work, within different human activities, two pitfalls are often detected if computer support is considered: a) technological communication difficulties, especially if the group is remotely located on heterogeneous hardware, associated with a fall in productivity and frequent social inadequacies of the group s computer support- b) the lack of integrated media processing tools available for group editing.In order to solve these problems, we suggest that Multimedia can be applied in two ways: to effectively support the necessary group communication links- and to enhance the expressiveness of the information edited. To test this statement we have been conceptualising and implementing a prototype system. Most of the techniques involved can be used in other tools that need multimedia capabilities or that support other specific types of group activities.The innovative aspects of the work are the use of multimedia techniques to support demanding applications, possibly on cross-platforms, and the integration of several concepts to support cooperation.
1993-01-01T00:00:00ZFast SpheresPatterson, John W.https://diglib.eg.org:443/handle/10.2312/68672022-03-28T11:55:16Z1993-01-01T00:00:00ZFast Spheres
Patterson, John W.
A new method for generating sphere-like images, using parabolic surfaces delimited by Bresenham s circle- generation algorithm, is presented. In many cases the resultant images are indistinguishable from spheres illuminated from a given single direction. The main form of the algorithm uses first and second integer differences to minimise computation and uses typically not more than one floating-point calculation per sphere. Two variants of the algorithm are given, one optimized for the special case of the light-source being behind the view-point, and one in which values are calculated for a z-buffer hidden-surface algorithm at the same time as the pixel values. The difference formulae can be exploited by differencing hardware or digital signal processors although very little arithmetic, typically five low-weight integer operations, including address calculation operations, is required per pixel on a conventional architecture.
1993-01-01T00:00:00Z