Sharif Digital Repository

In this paper, a system wide scheme is proposed to arrest voltage instability. This scheme consists of two stabilizing and securing parts. For post- contingency situations, where there are no equilibrium solutions, first, the stabilizing scheme finds the closest solvable operating point, and then passes this point to the securing scheme. The securing scheme brings the solvable, but insecure operating point, back to a secure and stable one. Also, a voltage stability indicator is proposed to monitor the available margin to the collapse point. The proposed stabilizing and securing model are solved using the sequential quadratic programming technique. ©2009 IEEE  

A large number of Wireless Sensor Network (WSN) security schemes have been proposed in the literature, relying primarily on symmetric key cryptography. To enable those, Random Key pre-Distribution (RKD) systems have been widely accepted. However, WSN nodes are vulnerable to physical compromise. Capturing one or more nodes operating with RKD would give the adversary keys to compromise communication of other benign nodes. Thus the challenge is to enhance resilience of WSN to node capture, while maintaining the flexibility and low-cost features of RKD. We address this problem, without any special-purpose hardware, proposing a new and simple idea: key splitting. Our scheme does not increase... 

In the last decade, various types of RFID security schemes have been proposed which have tried to provide all security and privacy requirements of end-users. In this paper, we cryptanalyze two new-found key exchange and key agreement security schemes which are proposed by Zhang et al. and Kim in 2012 and 2013 respectively. We present the reveal secret parameter, tag impersonation and traceability attacks on Zhang et al's protocol with success probability '1', and also we show that an attacker can impersonate the tag and the reader of Kim's protocol both with success probabilities '1/4'. We also present some modifications on the structure of studied schemes and propose two modified schemes... 

Recently, Radio Frequency Identification (RFID) and Near Field Communication systems are found in various user-friendly services that all of us deal with in our daily lives. As these systems are ubiquitously deployed in different authentication and identification applications, inferring information about our behavior will be possible by monitoring our use of them. In order to provide privacy and security requirements of RFID users in novel authentication applications, lots of security schemes have been proposed which have tried to provide secure and untraceable communication for end-users. In this paper, we investigate the privacy of three RFID security schemes which have been proposed...