Access control in a grid environment is a challenging issue because the heterogeneous nature and independent administration of geographically dispersed resources in grid require access control to use fine-grained policies. We established a task-and-role-based access-control model for computational grid (CG-TRBAC model), integrating the concepts of role-based access control (RBAC) and task-based...

A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high puri...

The latest researches on access control model are dramatically different from conventional ones. Nowadays, most attention is paid to accessing across organizational boundaries. So, how to identify the applicant and determine authorization with limited information; how to express and exchange control rules expediently; how to protect confidential information and enhance collaboration simultaneou...

Semiclathrate hydrate formers such as tetra-n-butylammonium bromide (TBAB), chloride (TBAC) and fluoride (TBAF) are promising compounds that mild the thermodynamic conditions of gas hydrates, considerably. The Clausius-Clapeyron equation is employed in this manuscript to calculate dissociation enthalpies methane/carbon dioxide/nitrogen + TBAF semiclathrate hydrates. A 460 cm3 stirred batch reac...

Nowadays interorganizational collaborations are evolving into large federated environments interconnecting organizations from all over the world. The relationships among these organizations are basically characterized by the need for competition and cooperation, essentially for sharing resources and services such as computing and storage capabilities. Enhanced autonomy and mobility are one of t...

Insider attack and espionage on computer-based information is a major problem for business organizations and governments. Knowledge Management Systems (KMSs) are not exempt from this threat. Prior research presented the Congenial Access Control Model (CAC), a relationship-based access control model, as a better access control method for KMS because it reduces the adverse effect of stringent sec...

A novel polyvinylidene fluoride (PVDF) tree-like nanofiber membrane (PVDF-TLNM) was fabricated by adding tetrabutylammonium chloride (TBAC) into a PVDF spinning solution via one-step electrospinning. The structure of the prepared membranes was characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and pore size analysis, and the hy...

In the present study, the speech-recognition performance of 50 subjects aged 63 to 83 years was measured for a wide range of materials (nonsense syllables, monosyllabic words, sentences) and listening conditions (presentation levels of 70 and 90 dB SPL, both in quiet and in a noise background). In addition to complete audiologic evaluations, measures of auditory processing (the Test of Basic Au...

Given that most of the gaseous constituents of industrial chimneys are usually carbon dioxide which is one of the most important greenhouse gases. It seems that the hydration process is one of the newest methods for the separation of this gas from gaseous mixtures. In the gas hydrate formation industry, in addition to disadvantages, there are some advantages such as gas separation, transmission...