Efficient unimodality test in clustering by signature testing

This paper provides a new unimodality test with application in hierarchical clustering methods. The proposed method denoted by signature test (Sigtest), transforms the data based on its statistics. The transformed data has much smaller variation compared to the original data and can be evaluated in a simple proposed unimodality test. Compared with the existing unimodality tests, Sigtest is more accurate in detecting the overlapped clusters and has a much less computational complexity. Simulation results demonstrate the efficiency of this statistic test for both real and synthetic data sets

Cryptanalysis of an Efficient Signcryption Scheme with Forward Secrecy Based on Elliptic Curve

The signcryption is a relatively new cryptographic technique that is supposed to fulfill the functionalities of encryption and digital signature in a single logical step. Several signcryption schemes are proposed throughout the years, each of them having its own problems and limitations. In this paper, the security of a recent signcryption scheme, i.e. Hwang et al.'s scheme is analyzed, and it is proved that it involves several security flaws and shortcomings. Several devastating attacks are also introduced to the mentioned scheme whereby it fails all the desired and essential security attributes of a signcryption scheme.Comment: 5 Pages, 2 Figure

LPKI - A Lightweight Public Key Infrastructure for the Mobile Environments

The non-repudiation as an essential requirement of many applications can be provided by the asymmetric key model. With the evolution of new applications such as mobile commerce, it is essential to provide secure and efficient solutions for the mobile environments. The traditional public key cryptography involves huge computational costs and is not so suitable for the resource-constrained platforms. The elliptic curve-based approaches as the newer solutions require certain considerations that are not taken into account in the traditional public key infrastructures. The main contribution of this paper is to introduce a Lightweight Public Key Infrastructure (LPKI) for the constrained platforms such as mobile phones. It takes advantages of elliptic curve cryptography and signcryption to decrease the computational costs and communication overheads, and adapting to the constraints. All the computational costs of required validations can be eliminated from end-entities by introduction of a validation authority to the introduced infrastructure and delegating validations to such a component. LPKI is so suitable for mobile environments and for applications such as mobile commerce where the security is the great concern.Comment: 6 Pages, 6 Figure

Effect of vitamin C and quercetin treatment on the liver histopathologic profile in congenital lead exposed male rat pups

Introduction: Lead is one of the most important environmental pollutants due to its vast use in various industries. Lead accumulation in different organs, especially the brain, liver and kidneys can cause serious health problems. Lead exposure is more dangerous during fetal period and childhood. Materials and Methods: Timed pregnant female rats divided into 6 groups. Group 1served as control group and received tap water, group 2 received 500 mg/liter lead acetate in the drinking water from 5th day of gestation up to 25th day post-partum, group 3 received the same dose of lead acetate along with daily IP injection of 40mg/kg quercetin, Group 4 received the same dose of lead acetate along with 2g/liter vitamin C, groups 5 and 6 received vitamin C and quercetin respectively like groups 2 and 3 but without lead acetate. On the 25th day postpartum, 6 male pups in each group were deeply anesthetized by chloroform; livers were removed and processed for Hematoxyline- Eosin staining. The microscopic slides were photographed and liver tissue morphological characteristics were evaluated. Results: Lead exposure caused extensive histopathologic changes in liver tissue including hepatocyte degradation, cell nucleus bifurcation and inflammation around hepatic veins. Quercetin and vitamin C treatment could prevent these pathologic changes to a considerable extent. Conclusion: Vitamin C in drinking water and quercetin via IP injection could protect the liver tissue against lead hepatotoxic effects. © 2015, Iranian Society of Physiology and Pharmacology. All rights reserved