Sharif Digital Repository

ANSI RBAC is a standard for a consistent and uniform definition on Role Based Access Control features and their functional specifications ANSI (2004) [1]. We analyze both static and dynamic separation of duty constraints specifications in the ANSI RBAC standard and evaluate their reliabilities. We then suggest necessary improvements for making them completely reliable  

Various damage indexes have been introduced in recent years incorporating different parameters for estimating structural damage. Amongst these indexes, Plastic Ductility and Drift have been the center of attention of standards and building codes, like FEMA-356, because of their straightforward physical interpretation and ease of calculation. In this paper, several steel moment frames have been considered and their responses have been evaluated under a set of scaled earthquakes. A group of various damage indexes, which included cumulative and non cumulative, cyclic fatigue based, deformation based and modal parameter based, has been considered and the damage to structures has been evaluated... 

Access to potable water with standard quality is an inevitable component of human's lives. Freeze desalination, by consuming lower energy compared to other techniques, relies on the exertion of a cold source which is then accompanied by simultaneous rejection of impurities from water. Regarding this, a numerical study on freeze desalination in a hollow cylinder is carried out to determine the effects of the design variables such as heat flux, hydraulic diameter, initial salt concentration, and freezing time on the ice mass, ice salinity, ice generation speed, and Nusselt number on the cold surface of the inner tube. Results show that increasing the value of heat flux from −250 [Formula... 

The diagrid structural systems are mainly used for their structural capabilities and architectural aesthetic possibilities which are provided by the unique geometric configurations of these systems. However, the seismic performance factors of these structural systems are not yet explicitly recommended in the existing building codes. In this study, the seismic performance factors (SPFs) of 6- to 24-story steel diagrid structures are determined considering the post-buckling behavior of diagonal members in compression. Also, the effect of change in span length and the diagonal angles on the SPFs of diagrid structures is studied. The ATC-19 coefficient method is used for calculating the SPFs... 

(Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen)3- Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with XU7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as palladium, platinum and rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of... 

In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the... 

In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the...