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Secret Key Agreement Over Multipath Channels Exploiting a Variable-Directional Antenna
Valery Korzhik,Viktor Yakovlev,Yuri Kovajkin,Guillermo Morales-Luna
International Journal of Advanced Computer Sciences and Applications , 2012,
Abstract: We develop an approach of key distribution protocol(KDP) proposed recently by T.Aono et al., where the security of KDP is only partly estimated in terms of eavesdropper's key bit errors. Instead we calculate the Shannon's information leaking to a wire tapper and also we apply the privacy amplification procedure from the side of the legal users. A more general mathematical model based on the use of Variable-Directional Antenna (VDA) under the condition of multipath wave propagation is proposed. The new method can effectively be used even in noiseless interception channels providing thus a widened area with respect to practical applications. Statistical characteristics of the VDA are investigated by simulation, allowing to specify the model parameters. We prove that the proposed KDP provides both security and reliability of the shared keys even for very short distances between legal users and eavesdroppers. Antenna diversity is proposed as a mean to enhance the KDP security. In order to provide a better performance evaluation of the KDP, it is investigated the use of error correcting codes.
Valery Korzhik,,Anton Ushmotkin,,Artem Razumov,,Guillermo Morales-Luna
International Journal of Computer Science & Applications , 2010,
Secret Key Agreement Over Multipath Channels Exploiting a Variable-Directional Antenna
Valery Korzhik,Viktor Yakovlev,Guillermo Morales-Luna,Yuri Kovajkin
Mathematics , 2011,
Abstract: We develop an approach of key distribution protocol (KDP) proposed recently by T. Aono et al. A more general mathematical model based on the use of Variable-Directional Antenna (VDA) under the condition of multipath wave propagation is proposed. Statistical characteristics of VDA were investigated by simulation, that allows us to specify model parameters. The security of the considered KDP is estimated in terms of Shannon's information leaking to an eavesdropper depending on the mutual locations of the legal users and the eavesdropper. Antenna diversity is proposed as a mean to enhance the KDP security. In order to provide a better agreement of the shared keys it is investigated the use of error-correcting codes.
Wet Paper Coding for Watermarking of Binary Images
Michail Zubarev,Valery Korzhik,Guillermo Morales-Luna
Mathematics , 2008,
Abstract: We propose a new method to embed data in binary images, including scanned text, figures, and signatures. Our method relies on the concept of wet paper codes. The shuffling before embedding is used in order to equalize irregular embedding capacity from diverse areas in the image. The hidden data can be extracted without the original binary image. We illustrate some examples of watermarked binary images after wet paper coding.
Key Distribution Protocols Based on Extractors Under the Condition of Noisy Channels in the Presence of an Active Adversary
Viktor Yakovlev,Valery Korzhik,Guillermo Morales-Luna,Mihail Bakaev
Mathematics , 2010,
Abstract: We consider in this paper the information-theoretic secure key distribution problem over main and wire-tap noise channels with a public discussion in presence of an active adversary. In contrast to the solution proposed by ourselves for a similar problem using hashing for privacy amplification, in the current paper we use a technique of extractors. We propose modified key distribution protocols for which we prove explicit estimates of key rates without the use of estimates with uncertain coefficients in notations $O,\Omega,\Theta$. This leads in the new conclusion that the use of extractors is superior to the use of hash functions only with the very large key lengths $\ell$ (of order $\ell>10^5$ bits). We suggest hybrid key distribution protocols consisting from two consecutively executed stages. At the fist stage it is generated a short authentication key based on hash function, whereas at the second stage it is generated the final key with the use of extractors. We show that in fact the use of extraction procedure is effective only at the second stage. We get also some constructive estimates of the key rates for such protocols.
Minimal obstructions for 1-immersions and hardness of 1-planarity testing
Vladimir P. Korzhik,Bojan Mohar
Mathematics , 2011,
Abstract: A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by no more than one other edge (and any pair of crossing edges cross only once). A non-1-planar graph $G$ is minimal if the graph $G-e$ is 1-planar for every edge $e$ of $G$. We construct two infinite families of minimal non-1-planar graphs and show that for every integer $n > 62$, there are at least $2^{(n-54)/4}$ nonisomorphic minimal non-1-planar graphs of order $n$. It is also proved that testing 1-planarity is NP-complete.
New Trends in Non-Destructive Evaluation of Surface Hardened Layers and Coatings  [PDF]
Valery Vengrinovich
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2013, DOI: 10.4236/jsemat.2013.32020

This article should not be considered as a full review of current methods for non-destructive testing of surface layers. Rather, it is a subjective in this area. However, the article provides some review of the challenges posed by the current state of surface layers treatment techniques on the area of Non-Destructive materials evaluation: enhancement of the sensitivity to the type of defects, increasing resolution to submicron values, the requirement to diagnose the surface layers with depth resolution of properties, diagnosis of multilayer multicomponent surface layers and coatings, treated with concentrated energy.

Assessment of Changes in Ice Regime Characteristics of Russian Lakes and Rivers under Current Climate Conditions  [PDF]
Valery Vuglinsky
Natural Resources (NR) , 2017, DOI: 10.4236/nr.2017.86027
Abstract: This article deals with assessment of changes in ice cover duration and maximum ice cover thickness for the last three decades compared with the previous period by the example of observation data for 28 hydrometric stations on rivers and 10 hydrological stations on lakes. Estimations of homogeneity and trends of long term serious of above mentioned rivers and lakes ice regime characteristics for three time periods were carried out using Student and Fisher criteria. Assessment of changes in ice regime characteristics for the period 1980-2010 compared with the period of stationary climate (from the beginning of observations until 1979) using two methodological approaches was made. The results can be used for solving problems of economy branches adaptation in case of rivers and lakes used in winter conditions.
Photochemical Properties of Precipitated Solid Aerosol Produced by Burning of Titanium Microparticles under Ambient Air  [PDF]
Valery Zakharenko, Sophia Khromova
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.12017
Abstract: In order to neutralize a drastic pollution of the environment (technogenic catastrophe) it is suggested to use technogenic technologies of chemical compound decontamination. One in such technologies can be the technology using metal oxide solid aerosols which are active in removal of pollutant compounds and obtainable by combustion under ambient air of appropriate metal particles, for example, aluminum, magnesium, titanium and etc. It is shown that the titanium dioxide out of an solid aerosol, obtained by pyrotechnic mixture combustion containing titanium microparticles has optic, chemical and photocatalytic properties close to properties of titanium dioxide produced by a different way. The production of such aerosol in direct place of a technogenic catastrophe can be made for the cleaning of atmosphere near a pollution source.
Combined Algorithms of Optimal Resource Allocation  [PDF]
Valery I. Struchenkov
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.31013
Abstract: Under study is the problem of optimum allocation of a resource. The following is proposed: the algorithm of dynamic programming in which on each step we only use the set of Pareto-optimal points, from which unpromising points are in addition excluded. For this purpose, initial approximations and bilateral prognostic evaluations of optimum are used. These evaluations are obtained by the method of branch and bound. A new algorithm “descent-ascent” is proposed to find upper and lower limits of the optimum. It repeatedly allows to increase the efficiency of the algorithm in the comparison with the well known methods. The results of calculations are included.
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