Algebraic Attack on the Alternating Step(r,s)Generator

The Alternating Step(r,s) Generator, ASG(r,s), is a clock-controlled sequence generator which is recently proposed by A. Kanso. It consists of three registers of length l, m and n bits. The first register controls the clocking of the two others. The two other registers are clocked r times (or not clocked) (resp. s times or not clocked) depending on the clock-control bit in the first register. The special case r=s=1 is the original and well known Alternating Step Generator. Kanso claims there is no efficient attack against the ASG(r,s) since r and s are kept secret. In this paper, we present an Alternating Step Generator, ASG, model for the ASG(r,s) and also we present a new and efficient algebraic attack on ASG(r,s) using 3(m+n) bits of the output sequence to find the secret key with O((m^2+n^2)*2^{l+1}+ (2^{m-1})*m^3 + (2^{n-1})*n^3) computational complexity. We show that this system is no more secure than the original ASG, in contrast to the claim of the ASG(r,s)'s constructor.Comment: 5 pages, 2 figures, 2 tables, 2010 IEEE International Symposium on Information Theory (ISIT2010),June 13-18, 2010, Austin, Texa

Evaluation of bacteriological and chemical quality of dialysis water and fluid in Isfahan, central Iran

Background: Chemical and microbial quality of water used in hemodialysis play key roles in a number of dialysisrelated complications. In order to avoid the complications and to guarantee safety and health of patients therefore, vigorous control of water quality is essential. The objective of present study was to investigate the chemical and bacteriological characteristics of water used in dialysis centers of five hospitals in Isfahan, central Iran. Methods: A total of 30 water samples from the input of dialysis purification system and dialysis water were analyzed for chemical parameters. Heterotrophic plate count and endotoxin concentration of drinking water, dialysis water and dialysis fluid of 40 machines were also monitored over a 5-month period in 2011-2012. Results: Concentration of the determined chemicals (copper, zinc, sulfate, fluoride, chloramines and free chlorine) did not exceed the recommended concentration by the Association for the Advancement of Medical Instrumentation (AAMI) exclude lead, nitrate, aluminum and calcium. Furthermore, the magnesium; cadmium and chromium concentration exceeded the maximum level in some centers. No contamination with heterotrophic bacteria was observed in all samples, while the AMMI standard for endotoxin level in dialysis fluid (<2 EU/ml) was achieved in 95 of samples. Conclusion: Dialysis water and fluid failed to meet the all chemical and bacteriological requirements for hemodialysis. To minimize the risk of contaminants for hemodialysis patients therefore, a water quality management program including monitoring, maintenance and development of water treatment system in hemodialysis centers is extremely important. In addition, an appropriate disinfection program is needed to guarantee better control of bacterial growth and biofilm formation. © 2016, Iranian Journal of Public Health. All rights reserved

Broadcast Caching Networks with Two Receivers and Multiple Correlated Sources

The correlation among the content distributed across a cache-aided broadcast network can be exploited to reduce the delivery load on the shared wireless link. This paper considers a two-user three-file network with correlated content, and studies its fundamental limits for the worst-case demand. A class of achievable schemes based on a two-step source coding approach is proposed. Library files are first compressed using Gray-Wyner source coding, and then cached and delivered using a combination of correlation-unaware cache-aided coded multicast schemes. The second step is interesting in its own right and considers a multiple-request caching problem, whose solution requires coding in the placement phase. A lower bound on the optimal peak rate-memory trade-off is derived, which is used to evaluate the performance of the proposed scheme. It is shown that for symmetric sources the two-step strategy achieves the lower bound for large cache capacities, and it is within half of the joint entropy of two of the sources conditioned on the third source for all other cache sizes.Comment: in Proceedings of Asilomar Conference on Signals, Systems and Computers, Pacific Grove, California, November 201

Teratogenic effects of gabapentin on the skeletal system of Balb/C mice fetuses

Objectives: To evaluate the effects of gabapentin )GBP( administration on mice fetuses. Methods: This study was carried out in Birjand University of Medical Sciences during 2008. Thirty Balb/c pregnant mice were divided randomly into 3 groups: 2 experimental groups that received 25 mg/kg )I( and 50 mg/kg )II( of GBP intraperitoneally for the first 15 days of pregnancy, and a control group that received normal saline. External observations of day 18 fetuses and skeleton double staining were performed. Results: Both experimental groups showed similar disorders that can be categorized as the following: 1( decrease of fetal body weight and increase of fetal resorption, 2( macroscopic malformations, and 3( skeletal malformations. Fetal body weights were significantly lower, and fetus resorptions were significantly higher in both treated groups compared to the control group. Macroscopic malformations included exencephaly, limbs defects, brachygnathia, vertebral column deformity, and fetuses with severe retarded growth. Skeletal malformations included delayed ossification, scoliosis, calvaria deformity, and mandibular hypoplasia. Conclusion: This study revealed that GBP can induce previously unreported severe malformations if it is used continuously during the implantation, neurulation, and organogenesis stages of pregnancy. Therefore, it is suggested that great caution should be exercised in using GBP during the early stages of pregnancy until further studies are performed to better understand these effects