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

NEW STATISTICAL BOX-TEST AND ITS POWER

In this paper, statistical testing of $N$ multinomial probabilities is studied and a new box-test, called \emph{Quadratic Box-Test}, is introduced. The statistics of the new test has $\chi^2_s$ limit distribution as $N$ and the number of trials $n$ tend to infinity, where $s$ is a parameter. The well-known empty-box test is a particular case for $s=1$. The proposal is quite different from Pearson\u27s goodness-of-fit test, which requires fixed $N$ while the number of trials is growing, and linear box-tests. We prove that under some conditions on tested distribution the new test\u27s power tends to $1$. That defines a wide region of non-uniform multinomial probabilities distinguishable from the uniform. For moderate $N$ an efficient algorithm to compute the exact values of the first kind error probability is devised

Applicability of universal Bacteroidales genetic marker for microbial monitoring of drinking water sources in comparison to conventional indicators

Water quality monitoring is essential for the provision of safe drinking water. In this study, we compared a selection of fecal indicators with universal Bacteroidales genetic marker to identify fecal pollution of a variety of drinking water sources. A total of 60 samples were collected from water sources. The microbiological parameters included total coliforms, fecal coliforms, Escherichia coli and fecal streptococci as the fecal indicator bacteria (FIB), Clostridium perfringens and H2S bacteria as alternative indicators, universal Bacteroidales genetic marker as a promising alternative fecal indicator, and Salmonella spp., Shigella spp., and E. coli O157 as pathogenic bacteria. From 60 samples analyzed, Bacteroidales was the most frequently detected indicator followed by total coliforms. However, the Bacteroidales assay failed to detect the marker in nine samples positive for FIB and other alternative indicators. The results of our study showed that the absence of Bacteroidales is not necessarily an evidence of fecal and pathogenic bacteria absence and may be unable to ensure the safety of the water. Further research, however, is required for a better understanding of the use of a Bacteroidales genetic marker as an indicator in water quality monitoring programs

An innovative configuration for new marine current turbine

Researchers have shown growing interest in the development of traditional Savonius turbine due to their numerous benefits such as structural simplicity, self-start ability, relatively low operating speed, bi-directional rotational ability and lower environmental impact. However, Savonius turbines exhibits lower efficiency as compared to other similar marine current turbines. This paper proposes a novel design concept for the Savonius turbine. In addition, this work investigates flow and pressure distribution around the buckets of novel rotor with a two-dimensional unsteady numerical model. The proposed marine current turbine with novel design is named as Reza Turbine. Numerical model employed the Dynamic Mesh Method (DMM) for modelling mesh movement around the blades of rotor for different position with respect to computational domain. Developed numerical model solves the unsteady Reynolds averaged Navier-Stokes equations by using SIMPLE algorithm. In addition, we conducted an experiment in a low speed wind tunnel to obtain important performance parameters namely torque, power and performance for the proposed turbine. A set of flow speed were used as inlet boundary condition for both numerical and experimental model. A comparison between numerical and experimental results shows that the SST k-ω turbulence model gives satisfactory results for the developed novel turbine. The developed ReT is showed 52% improvement in efficiency as compared conventional Savonious turbine. Since the peak of power coefficient obtained was 0.321 for ReT, while 0.21 was reported for conventional Savonius turbine

Experimental investigation of an innovative configuration for new marine current turbine

The numerous benefits of Savonius turbine including simplicity in structure, appropriateness of its self-start ability, operating in relatively low velocity, independency from flow direction and its low environmental burdening have caused the Savonious to gain momentum in recent Marine Current Turbine research. However, the turbine suffers from low efficiency as compared with other water turbines. This paper proposes a novel Savonius turbine configuration design for marine currents. The new model design was tested in the Universiti Teknologi Malaysia (UTM) in the low-speed wind tunnel at different speeds while measuring parameters such as pressure and performance. The experiment was conducted by measuring the pressure distribution on blade surfaces. Various angles of the new rotor were tested at different speeds in the low-speed wind tunnel. The comparison revealed substantial improvement in turbine efficiency for the new configuration in comparison with the conventional design

Impact of technology foresight on the policy-making process in Iran

Technology foresight as a policy intelligence tool, can offer vital inputs for policy-making in various domains. The relationship between foresight and policy-making has been presented in the literature by the policy-related functions of foresight, but the literature reflects a theoretical gap with the systematic evaluation of the impact of foresight on policy-making. So this study tries to bridge the existing gap by development an evaluation model. The data collection tool is a questionnaire and in order to test the proposed model; a sample of fifteen experts is included. In this article a case study is conducted to implement the confirmed model in the real word and Partial Least Squares (PLSs) path analysis is used to advance our understanding of the relationships and the structure of the proposed model. The results confirm the proposed dimensions of the model and provide insight for those who are concerned with this topic