Sharif Digital Repository

Nowadays, security evaluation of software is a substantial matter in software world. Security level of software will be determined by wealth of data and operation which it provides for us. The security level is usually evaluated by a third party, named Software Security Certification Issuance Centers. It is important for software security evaluators to perform a sound and complete evaluation, which is a complicated process considering the increasing number of emerging threats. In this paper we propose a Threatened-based Software Security Evaluation method to improve the security evaluation process of software. In this method, we focus on existing threatened entities of software which in turn... 

Graphics Processing Units (GPUs) employ large register files to accommodate all active threads and accelerate context switching. Unfortunately, register files are a scalability bottleneck for future GPUs due to long access latency, high power consumption, and large silicon area provisioning. Prior work proposes hierarchical register file to reduce the register file power consumption by caching registers in a smaller register file cache. Unfortunately, this approach does not improve register access latency due to the low hit rate in the register file cache. In this article, we propose the Latency-Tolerant Register File (LTRF) architecture to achieve low latency in a two-level hierarchical... 

During the past decade, Electro-Hydraulic system has performed a significant role in industrial engineering as an actuator for high performance and precision positioning applications. In this case, many control methods have been developed for an electro-hydraulic actuated clutch. In this paper a Linear Quadratic Regulators (LQR) is proposed to trajectory control of a wet clutch actuated by a hydraulic servo valve mechanism. Simulation study was performed using linearized mathematical model of the system implemented in MATLAB software. Based on the simulation results performance of the proposed controller was evaluated and discussed  

By employing a few simple models of passive dynamic walking mechanism, we have shown the possibility of extending the boundaries of the maximum stable speed of these autonomous robots merely by changing their terrain. The replaced terrain consists of a series of parallel local slopes and is recognized as a general form of a ramp-stair surface. Although here, the mechanism of stabilization of the unstable locomotion patterns is not clearly known, the technique is quite simple and works effectively. The merit to the method over other strategies, could be described in two separate aspects: First, it is still completely passive; so we do not need any external energy to control the robot. Second,... 

This paper proposes a new technique called CFEDC to detect and correct control flow errors (CFEs) without program interruption. The proposed technique is based on the modification of application software and minor changes in the underlying hardware. To demonstrate the effectiveness of CFEDC, it has been implemented on an OpenRISC 1200 as a case study. Analytical results for three workload programs show that this technique detects all CFEs and corrects on average about 81.6% of CFEs. These figures are achieved with zero error detection /correction latency. According to the experimental results, the overheads are generally low as compared to other techniques; the performance overhead and the... 

Self-adaptive systems are systems that automatically adapt in response to environmental and internal changes, such as possible failures and variations in resource availability. Such systems are often realized by a MAPE-K feedback loop, where Monitor, Analyze, Plan and Execute components have access to a runtime model of the system and environment which is kept in the Knowledge component. In order to provide guarantees on the correctness of a self-adaptive system at runtime, the MAPE-K feedback loop needs to be extended with assurance techniques. To address this issue, we propose a coordinated actor-based approach to build a reusable and scalable model@runtime for self-adaptive systems in the...