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Coupling the adjacent zones for seepage analysis in porous media needs compatibility and equilibrium equations (equality of potential on coinciding nodes and conservation of flowing mass between zones, respectively). When stretched coordinate transformation is applied to the anisotropic zones, the Dirichlet boundary conditions remain unchanged, but the Neumann boundary condition should also be transformed. Similarly in a zoned problem, for the interface between zones, compatibility equations remain unchanged during the transformation while the equilibrium equations should be transformed. In this paper, transformed Neumann boundary conditions and equilibrium equations for the interface of... 

As semantic web grows, security concerns increase. One concern is controlling accesses to resources in this environment. In order to infer whether the access is allowed or not, different information of different entities including contextual information should be involved. From access control point of view, we divide the entities in semantic web into three categories: resources (objects), requesters (subjects), and environment (infrastructure, time, and location). In this paper, we present a semantic-based context-aware access control framework to be applied in semantic web, considered as a multi-domain environment. To handle context information in the framework, we propose a context... 

In order to overcome the shortcomings of the recent frameworks and mechanisms for semantic-based access control, this paper presents a semantic-based, context-aware, and multi-domain enabled framework implementing a semantic-based access control mechanism for Semantic Web. The access control framework is based on the MA(DL)2 model, which takes the semantic relationships among different entities into account. The framework handles the Semantic Web context by classifying and representing it through an ontology. Considering the MA(DL)2 model, the framework assumes SemanticWeb having some overlapped domains, which each contains an authority and a security agent. As a domain authority... 

In multi-domain environments, authorization policies for each administrative domain are determined by either one administrator or through cooperation of multiple administrators. Proposed logic-based models for multi-domain environments' authorization neither consider an administrator as the legislator of a policy in policies' representation nor specify the domain of a policy explicitly. Considering legislators in policy specification provides the possibility of presenting composite administration and utilizing administrators' characteristics in policy analysis such as conflict resolution. In this paper, we propose the syntax, proof theory, and semantics of a logic in which administrators are... 

A three-dimensio111nal boundary element solution for the seepage analysis in multi-domain general anisotropic media has been developed based on the transformation approach. Using analytical eigenvalues and eigenvectors of the hydraulic conductivity tensor, a closed-form coordinate transformation matrix has been provided to transform the quadratic form of governing equation of seepage for the general anisotropic media to the Laplace equation. This transformation allows the analysis to be carried out using any standard BEM codes for the potential theory on the transformed space by adding small pre- and post-processing routines. With this transformation, any physical quantity like the total...