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121.
This research paper aims to determine the genetic origin of the chemical elements in groundwater. It deals with the results of physicochemical parameters, to evaluate the hydro-geochemistry of groundwater in rural-urban fringe of district Bareilly, India. Pre- and post-monsoon sampling has been carried out, which reveals inter-seasonal variability effect on the hydro-geochemical processes. Geochemical modeling especially computation of saturation index was undertaken using the WATEQ4F model. Majority of samples fall in the category of undersaturation, which further suggests that groundwater still has potential to dissolve more minerals. Chemical categorizations of groundwater samples were performed with the help of the Aquachem model. Grouping of groundwater on the Piper diagram reveals a common composition and origin. In most of the area, water facies is of Ca(2+)-HCO(3)(-) type in both the seasons. It also indicates that in pre-monsoon, ion exchange is the dominant process, whereas in post-monsoon, both ion exchanges as well as reverse ion exchanges are reported in the groundwater of the study area. 相似文献
122.
123.
G.S. BadrinathAuthor Vitae Phalguni Gupta Author Vitae 《Future Generation Computer Systems》2012,28(1):287-305
This paper presents an efficient palmprint based human recognition system. Each palmprint is divided into several square overlapping blocks. Reconstruction error using principle component analysis (PCA) is used to classify these blocks into either a good block or a non-palmprint block. Features from each good block of a palmprint are obtained by binarising the phase-difference of vertical and horizontal phase. The Hamming distance is used to compute the matching score between the features of corresponding good blocks of enrolled and live palmprint. These matching scores are fused using weighted sum rule, where weights are based on the average discriminating level of a block relative to other blocks. The performance of the proposed system is analysed on different datasets of hand images and it has been observed that it achieves a Correct Recognition Rate of 100% with a low Equal Error Rate for all the datasets. The system is also evaluated for noisy and bad palmprint images. It is found to be robust as long as the noise density is less than 50% or the bad region is less than 64% of the images. 相似文献
124.
We address the problem of automated action selection policy synthesis for unmanned vehicles operating in adverse environments.
We introduce a new evolutionary computation-based approach using which an initial version of the policy is automatically generated
and then gradually refined by detecting and fixing its shortcomings. The synthesis technique consists of the automated extraction
of the vehicle’s exception states and Genetic Programming (GP) for automated composition and optimization of corrective sequences
of commands in the form of macro-actions to be applied locally. 相似文献
125.
This paper presents a new algorithm for extracting Free-Form Surface Features (FFSFs) from a surface model. The extraction algorithm is based on a modified taxonomy of FFSFs from that proposed in the literature. A new classification scheme has been proposed for FFSFs to enable their representation and extraction. The paper proposes a separating curve as a signature of FFSFs in a surface model. FFSFs are classified based on the characteristics of the separating curve (number and type) and the influence region (the region enclosed by the separating curve). A method to extract these entities is presented. The algorithm has been implemented and tested for various free-form surface features on different types of free-form surfaces (base surfaces) and is found to correctly identify and represent the features irrespective of the type of underlying surface. The representation and extraction algorithm are both based on topology and geometry. The algorithm is data-driven and does not use any pre-defined templates. The definition presented for a feature is unambiguous and application independent. The proposed classification of FFSFs can be used to develop an ontology to determine semantic equivalences for the feature to be exchanged, mapped and used across PLM applications. 相似文献
126.
G. Morell A. González-Berríos B. R. Weiner S. Gupta 《Journal of Materials Science: Materials in Electronics》2006,17(6):443-451
The synthesis and properties of sulfur-doped nanocrystalline diamond films were investigated. The films were deposited by
hot-filament chemical vapor deposition on Mo substrates using methane, hydrogen, and hydrogen disulfide. The nanocrystalline
nature of the material arises from the induction of continuous secondary nucleation in the chemical vapor deposition environment.
Complementary characterization tools were employed in order to obtain a comprehensive and coherent understanding of the correlations
between the structural and electronic properties. In particular, sulfur-doped nanocrystalline diamond films show n-type Hall
conductivity, enhanced field emission properties, and insensitivity to ion radiation. It was found that n-type doping of the
tetragonally-bonded carbon matrix together with a nano network of trigonally-bonded carbon are crucial elements for enhanced
field emission from nanocrystalline diamond. These conclusions and the corresponding supporting evidence are discussed. 相似文献
127.
L. J. Dhareshwar S. Chaurasia C. G. Murali N. K. Gupta B. K. Godwal 《Journal of Materials Science》2006,41(5):1623-1630
X-ray and ion emissions from high temperature plasmas from solid targets with different atomic numbers have been studied.
Plasma is generated using a high power Nd:Glass laser generating focused intensity in the range of 1012 to 1013 Watts/cm2 on targets. Plasma temperature is typically between 50 to 100 eV. X-ray emission scaling as a function of laser intensity
as well as ion velocity has been measured in these targets. Non-uniform plasma expansion and generation of fast ions are observed
for targets with higher atomic numbers. 相似文献
128.
Algebraic immunity for cryptographically significant Boolean functions: analysis and construction 总被引:13,自引:0,他引:13
Carlet C. Dalai D.K. Gupta K.C. Maitra S. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2006,52(7):3105-3121
Recently, algebraic attacks have received a lot of attention in the cryptographic literature. It has been observed that a Boolean function f used as a cryptographic primitive, and interpreted as a multivariate polynomial over F/sub 2/, should not have low degree multiples obtained by multiplication with low degree nonzero functions. In this paper, we show that a Boolean function having low nonlinearity is (also) weak against algebraic attacks, and we extend this result to higher order nonlinearities. Next, we present enumeration results on linearly independent annihilators. We also study certain classes of highly nonlinear resilient Boolean functions for their algebraic immunity. We identify that functions having low-degree subfunctions are weak in terms of algebraic immunity, and we analyze some existing constructions from this viewpoint. Further, we present a construction method to generate Boolean functions on n variables with highest possible algebraic immunity /spl lceil/n/2/spl rceil/ (this construction, first presented at the 2005 Workshop on Fast Software Encryption (FSE 2005), has been the first one producing such functions). These functions are obtained through a doubly indexed recursive relation. We calculate their Hamming weights and deduce their nonlinearities; we show that they have very high algebraic degrees. We express them as the sums of two functions which can be obtained from simple symmetric functions by a transformation which can be implemented with an algorithm whose complexity is linear in the number of variables. We deduce a very fast way of computing the output to these functions, given their input. 相似文献
129.
130.
Soil-cement blocks also known as compressed earth blocks or stabilised mud blocks are used for load bearing masonry. The paper focuses on the study of various characteristics of soil-cement blocks using highly sandy soils through an experimental investigation. Characteristics of soilcement blocks having three different cement contents (6%, 8% and 12%) have been examined. Paper reports results of influence of cement content on compressive strength, tensile strength, the initial rate of absorption (IRA), water absorption, rate of water absorption, surface porosity and pore size, stress-strain relationships and elastic properties of soil-cement blocks. The results indicate that there is 2.5 times increase in strength for doubling of cement content from 6%. IRA decreases drastically with the increase in cement content of the block. Saturated water content of the blocks is not sensitive to cement content, whereas rate of moisture absorption greatly depends on the cement content. Pore size decreases with increase in cement content of block, whereas surface porosity is independent of the cement content. Soil-cement block modulus varies between 2000 and 6000MPa. Elastic modulus increases by 2.5 times when the cement content is increased from 6 to 8%, whereas the increase in modulus is marginal when cement content goes from 8 to 12%. 相似文献