Dynamic User Role Assignment in Remote Access Control

The Role-Based Access Control (RBAC) model has been widely applied to a single domain in which users are known to the administrative unit of that domain, beforehand. However, the application of the conventional RBAC model for remote access control scenarios is not straightforward. In such scenarios, the access requestor is outside of the provider domain and thus, the user population is heterogeneous and dynamic. Here, the main challenge is to automatically assign users to appropriate roles of the provider domain. Trust management has been proposed as a supporting technique to solve the problem of remote access control. The key idea is to establish a mutual trust between the requestor and provider based on credentials they exchange. However, a credential doesn't convey any information about the behavior of its holder during the time it is being used. Furthermore, in terms of privileges granted to the requestor, existing trust management systems are either too restrictive or not restrictive enough. In this paper, we propose a new dynamic user-role assignment approach for remote access control, where a stranger requests for access from a provider domain. Our approach has two advantages compared to the existing dynamic user-role assignment techniques. Firstly, it addresses the principle of least privilege without degrading the efficiency of the access control system. Secondly, it takes into account both credentials and the past behavior of the requestor in such a way that he cannot compensate for the lack of necessary credentials by having a good past behavior

Metaheuristic Algorithm for Solving Biobjective Possibility Planning Model of Location-Allocation in Disaster Relief Logistics

Thousands of victims and millions of affected people are hurt by natural disasters every year. Therefore, it is essential to prepare proper response programs that consider early activities of disaster management. In this paper, a multiobjective model for distribution centers which are located and allocated periodically to the damaged areas in order to distribute relief commodities is offered. The main objectives of this model are minimizing the total costs and maximizing the least rate of the satisfaction in the sense of being fair while distributing the items. The model simultaneously determines the location of relief distribution centers and the allocation of affected areas to relief distribution centers. Furthermore, an efficient solution approach based on genetic algorithm has been developed in order to solve the proposed mathematical model. The results of genetic algorithm are compared with the results provided by simulated annealing algorithm and LINGO software. The computational results show that the proposed genetic algorithm provides relatively good solutions in a reasonable time

A New Method for Fault Current Limiting and Voltage Compensating in Power Systems Using Active Superconducting Current Controller

In this paper, a new method for both fault current limiting and voltage compensating using Active Superconducting Current Controller (ASCC) is proposed. The main objective of this paper is to present an appropriate control strategy for ASCC to achieve both the fault current limiting and voltage compensation purposes. Three different operating modes are defined for ASCC including normal mode, fault current limiting mode, and voltage compensation mode and a proper control strategy is designed for each mode. For the fault current limiting, the model of a typical three-phase system with ASCC is simulated and different states for current limiting in different levels are defined. Also, for the voltage compensating mode, the PI model for the line is considered and the line transmission matrix is obtained when the ASCC is connected at the sending end and middle of the line. Finally, proper settings for ASCC are determined such that the magnitude of the receiving end and the sending end voltages become equal. Simulation results using MATLAB software confirm the proper performance of the proposed method

Entropy generation of pseudo-plastic non-Newtonian nanofluids in circular duct under constant wall temperature

In this paper the second law analysis of thermodynamic irreversibilities in pseudo-plastic non-Newtonian nanofluids through a circular duct under uniform wall temperature thermal boundary have been carried out for laminar flow condition. This nanofluid consists of sodium carboxymethyl cellulose (CMC)–water and two different types of nanoparticles; namely, CuO and Al2O3. Entropy generation is obtained for various Power law number, various volume concentration of nanoparticles, various dimensionless temperature and various Reynolds number. It is found that with the decreasing Power law number and duct length values, total entropy generation at fixed Reynolds number decreases and with increasing wall temperature values, total entropy generation increases, also entropy generation decreases with increasing volume concentration of nanoparticles

Owner-Based Role-Based Access Control OB-RBAC

Administration of an access control model deals with the question of who is authorized to update policies defined on the basis of that model. One of the models whose administration has absorbed relatively large research is the Role-Based Access Control (RBAC) model. All the existing role-based administrative models fall into the category of administrator based decentralized approach. In such an approach, a group of administrators are given firstly, the authority of updating authorizations for operative roles and secondly, the authority of delegating the previous right to other lower-level administrators. However, in organizations with informal and flexible structure, like academic and research-oriented organizations such a sharp distinction between administrative roles and operative roles might not exist. Here, each role may take part in both operative and administrative decisions such that more mission-oriented decisions are made by senior roles and more specialized-level decisions are made by junior roles. In this paper, we study a new class of access control model called Owner-Based Role-Based Access Control (OB-RBAC) which is suitable for such environments. The OB-RBAC model utilizes the advantages of both Discretionary Access Control (DAC)and RBAC. In particular, the OB-RBAC model builds a policy model which not only fulfills the organizational restrictions but enjoys the flexible administration of the DAC model

A Multi-period Multi-objective Location- routing Model for Relief Chain Management under Uncertainty

Natural disasters, accidents, and crises, that cause widespread destruction and inflict heavy casualties, accentuate the importance of a careful planning to deal with the aftermath and mitigate their impacts responsively. Thus, the logistics of disaster relief is one of the main activities in disaster management. In this paper, the response phase of the disaster management cycle is considered and a multi-objective model for location and routing of vehicles is presented. Uncertainties in transfer time, demands of regional warehouses in the damaged areas and inventories at supply centers in different periods are taken into account. Three objectives are considered in this model. Two objectives consist of minimizing total time required to reach the damaged areas and maximizing satisfaction of the damaged areas. The third objective, which is of secondary importance, attempts to minimize total costs, including startup costs, transfer costs, and shortage costs. In order to convert the proposed multi-objective formulation to a single objective one, Global Criterion approach is applied. Afterwards, the obtained single objective model is solved using an efficient genetic algorithm and simulated annealing. Finally, a case study in Southern Khorasan is conducted and the applicability of the proposed model is examined

A Robust Programming Approach to Bi-objective Optimization Model in the Disaster Relief Logistics Response Phase

Accidents and natural disasters and crises coming out of them indicate the importance of an integrated planning to reduce their effected. Therefore, disaster relief logistics is one of the main activities in disaster management. In this paper, we study the response phase of the disaster management cycle and a bi-objective model has been developed for relief chain logistic in uncertainty condition including uncertainty in traveling time an also amount of demand in damaged areas. The proposed mathematical model has two objective functions. The first one is to minimize the sum of arrival times to damaged area multiplying by amount of demand and the second objective function is to maximize the minimum ratio of satisfied demands in total period in order to fairness in the distribution of goods. In the proposed model, the problem has been considered periodically and in order to solve the mathematical model, Global Criterion method has been used and a case study has been done at South Khorasan