Sharif Digital Repository

Semantic technology provides an abstraction layer above existing computational environments, especially the Web, to give information a well-defined meaning. Moving toward semantic-aware environments imposes new security requirements. One of the most important requirement is the authorization and security policy inference based on the existing semantic relationships in the abstract (conceptual) layer. Most of the authorization models proposed for these environments so far are incomplete and their inference rules are not guaranteed to be consistent, sound, and complete. To have a sound and complete system for policy specification and inference, in this thesis, a family of modal logics, called... 

The emergence of semantic technology and its usage in different computational environments (especially the distributive environments) has increased the machine intelligence for more interoperability.This has resulted an abstraction (conceptual) layer above existing information and resources in these environments. Based on the unique characteristics of the semantic-aware environments, most of the proposed models for other environments are not applicable to this area, as they do not meet the security requirements of these environments. MA(DL)2-AM and SBAC are among the models that have satisfied a large portion of these requirements. Although documents are important assets of organizations... 

Fifth-generation mobile data networks are revolutionizing the way we communicate, work, and live. This generation of mobile data promises higher speeds, lower latency ,and greater capacity compared to previous generations. The technology is widely used to build private networks, and a variety of open-source and commercial implementations for its components have been developed. These implementations serve a broad spectrum of users, including academic, laboratory, and industrial environments. Despite its groundbreaking capabilities, service-based 5G networks face serious internal security threats such as identity spoofing and unauthorized access to network functions. Attackers who exploit...