Sharif Digital Repository

With the advent of semantic technology, access control cannot be done in a safe way unless the access decision takes into account the semantic relationships among the entities in a semantic-aware environment. SBAC model considers this issue in its decision making process. However, time plays a crucial role in new computing environments which is not supported in the model. In this paper we introduce the Temporal Semantic Based Access Control model (TSBAC), as an extension of SBAC, which enhances the specification of user-defined authorization rules by constraining time interval and temporal expression over users' history of accesses. A formal semantics for temporal authorizations is provided... 

With the advent of semantic technology, access control cannot be done in a safe way unless the access decision takes into account the semantic relationships between entities in a semantic-aware environment. SBAC model considers this issue in the decision making process. However, time plays a crucial role in new computing environments which is not supported in this model. In this paper we introduce temporal semantic based access control model (TSBAC), as an extension of SBAC model, which enhances the specification of user-defined authorization rules by constraining time interval and temporal expression over users' history of accesses. A formal semantics for temporal authorizations is provided... 

Time plays a crucial role in access control for new computing environments, which is not supported in traditional access control models. In this paper, we propose a Generalized Temporal History Based Access Control (GTHBAC) model, aimed at integrating history-based constraints along with a generic access control model. GTHBAC enhances the specification of user-defined authorization rules by constraining time interval and temporal expression over users' history of accesses. Due to different application needs, GTHBAC uses two different time schemes, i.e., real time and logical time, in its authorization rules. A formal semantics for temporal authorizations is provided, and conflicting... 

With the advent of semantic technology' access control cannot be done in a safe way unless the access decision takes into account the semantic relationships among the entities in a semantic-aware environment. The SBAC model (Semantic Based Access Control model) considers this issue in its decision making process. However' time plays a crucial role in new computing environments'which is not supported in SBAC. In this paper' we propose the Temporal Semantic Based Access Control (TSBAC) model' as an extension of SBAC' which enhances the specification of user-defined authorization rules by constraining time interval and temporal expression over users' history of accesses. TSBAC uses logical... 

Ground-source heat pumps, as the most environmentally friendly and energy-efficient air conditioning technology, suffer from a great required length of ground heat exchanger, partly arising from the low thermal conductivity of high-density polyethylene tubes commonly used in ground heat exchangers. In an attempt to find a replacement with an acceptable thermal conductivity for high-density polyethylene tubes, in this study, first, a comprehensive comparative study on fillers commonly used in thermally conductive polymer composites and resulting high-density polyethylene composites was conducted. Then, based on the advantages and disadvantages presented, an appropriate composite was selected... 

In this article, a novel microstrip antenna for the new industrial, scientific, and medical (ISM) band (24-25 GHz) with a flexible substrate is proposed. This antenna has a small dimension, high gain, and large bandwidth (BW) in the ISM band. Several tests such as bending tests and gas environment tests are performed to show the potential of the antenna in body area networks' (BANs) applications. The design procedure starts with a simple monopole antenna with a simple ground plane. Then, to change the effective permittivity of the substrate, an array of half circles is subtracted from the ground plane. To avoid increasing the dimension of the antenna, a triangular part and a shunt are added... 

There are limitations in current medications of articular cartilage injuries. Although injectable bioactive hydrogels are promising options, they have decreased biomechanical performance. Researchers should consider many factors when providing solutions to overcome these challenges. In this study, we created an injectable composite hydrogel from chitosan and human acellular cartilage extracellular matrix (ECM) particles. In order to enhance its mechanical properties, we reinforced this hydrogel with microporous microspheres composed of the same materials as the structural building blocks of the scaffold. Articular cartilage from human donors was decellularized by a combination of physical,... 

Introduction: One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin. Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare... 

Nanotechnology has begun to play a remarkable role in various fields of science and technology. In biomedical applications, nanoparticles have opened new horizons, especially for biosensing, targeted delivery of therapeutics, and so forth. Among drug delivery systems (DDSs), smart nanocarriers that respond to specific stimuli in their environment represent a growing field. Nanoplatforms that can be activated by an external application of light can be used for a wide variety of photoactivated therapies, especially light-triggered DDSs, relying on photoisomerization, photo-cross-linking/un-cross-linking, photoreduction, and so forth. In addition, light activation has potential in photodynamic... 

Estate administration involves managing and distributing a deceased individual’s assets to beneficiaries, as well as managing the liabilities. This process comprises legal, financial, and administrative tasks that ensure assets are transferred based on the deceased's wishes and in accordance with the law. In Southeast Asia countries such as Indonesia, Malaysia and Brunei where Muslims represents the majority of population, the Islamic law plays an integral part in the inheritance management as the process to be in line with the Islamic teachings and principle. The role of the syariah authority namely the syariah courts is prevalent and therefore, abidance to the rule under the syariah legal... 

A novel intelligent semi-active control system for an eleven degrees of freedom passenger car's suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network... 

Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the...