With the growing need for multimedia data management, security requirements are becoming very crucial. Composing multimedia documents involves bringing together media objects that exist in various formats. These objects may reside in a distributed environment and belong to different security domains. We propose a time-augmented colored Petri net model for multimedia document composition that allows the specification of multilevel security. The model also allows handling of multiple security policies and hierarchical and path based protection schemes.
In this paper we present the preliminary work we have done to secure an object oriented database. Faced with the difficulties to implement the existing models such as the SODA model [6], we suggest two different approaches which may be complementary. The central idea of our first approach is to provide the user with a single level virtual database which is derived from an object oriented database which supports multilevel entities. The second is based on the decomposition of a multilevel object oriented database into a collection of single level databases. We have not yet fully analyzed difficulties to implement these models, but we feel that they would probably considerably reduce the implementation effort in comparison with the SODA model.
This article presents a study of individual variation in computer-mediated communication. Different reduction processes, which reduce the formality and usually the orthographical form of an express ...