Conference Papers
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Item Severity of quenching and kinetics of wetting of nanofluids and vegetable oils(ASTM International, 2010) Jagannath, V.; Prabhu, K.N.In the present work, the suitability of vegetable oil blends with mineral oil and alumina based nanofluids as quench media for industrial heat treatment was investigated. Sunflower oil, palm oil, and mineral oil were used for preparing the blends. Alumina based nanofluids of varying concentrations ranging from 0.01-4 % were used. The size of alumina particles was about 50 nm. The severity of quenching and heat transfer coefficients were estimated during quenching of copper probes. Heat transfer coefficients were estimated using a lumped heat capacitance model. The static contact angle was measured on copper substrates having a surface texture similar to the probes used for estimation of heat transfer coefficients. A dynamic contact angle analyzer was used for this purpose. The measured contact angles of nanofluids on copper were high compared to oils, indicating poor wetting by quench media that are polar in nature. Wetting characteristics had a significant effect on heat transfer coefficients estimated during quenching. Copyright © 2009 by ASTM International.Item Computer controlled intrusion-detector and automatic firing-unit for border security(2010) Vittal, K.P.; Ajay, P.P.; Shenoy, S.B.; Srinivas Rao, C.H.S.This paper describes a novel computer-controlled intrusion-detector and automatic firing unit, which may be used for the surveillance of borders, either of a country, or of areas requiring high security, especially in regions of extreme climatic conditions, where it is difficult to deploy personnel. This system not only detects intrusion but also provides a video-coverage of the suspicious area, for remote vigilance, via a satellite based communication system. It is also provided with automatic firing mechanisms which can be used to automatically locate and fire at the target. Thus, several kilometres of the borders, which would have otherwise required several hundred personnel, can be effortlessly monitored with this system, with only a few personnel. Since, the actual firing occurs only after an authoritative personnel has doubly confirmed the presence of an intruder, chances of firing at innocent people are completely ruled out. As thermal cameras are used for imaging, this system is immune to changes in ambient conditions, and therefore, is equally suited for operation during the night. This paper also throws light on the prototype of this system, which has been successfully developed. © 2010 IEEE.Item Medical image segmentation using improved mountain clustering technique version-2(2010) Verma, N.K.; Roy, A.; Vasikarla, S.This paper proposes Improved Mountain Clustering version-2 (IMC-2) based medical image segmentation. The proposed technique is a more powerful approach for medical image based diagnosing diseases like brain tumor, tooth decay, lung cancer, tuberculosis etc. The IMC-2 based medical image segmentation approach has been applied on various categories of images including MRI images, dental X-rays, chest X-rays and compared with some widely used segmentation techniques such as K-means, FCM and EM as well as with IMC-1. The performance of all these segmentation approaches is compared on widely accepted validation measure, Global Silhouette Index. Also, the segments obtained from the above mentioned segmentation approaches have been visually evaluated. © 2010 IEEE.Item Multi-agent search strategy based on centroidal Voronoi configuration(2010) Guruprasad, K.R.; Ghose, D.We propose a combined deploy and search strategy for multi-agent systems using Voronoi partition. Agents such as mobile robots (AGVs, UAVs, or USVs) search the space to acquire knowledge about the space. Lack of information about the search space is modeled as an uncertainty density distribution, which is known a priori to all the agents at the beginning of search. It is shown that when the agents are located at the centroid of Voronoi cells, computed with the perceived uncertainty density, reduction in uncertainty density is maximized. While moving toward this optimal configuration, the agents simultaneously perform search acquiring the information about the search space, thereby reducing the uncertainty density. The proposed search strategy is guaranteed to reduce the average uncertainty density to any arbitrary level. Simulation experiments are carried out to validate the proposed search strategy and compare its performance with sequential deploy and search strategy proposed in the literature. The simulation results indicate that the proposed strategy performs better than sequential deploy and search in terms of faster search, and smoother and shorter robot trajectories. ©2010 IEEE.Item Performance analysis of energy efficient asymmetric coding and modulation schemes for wireless sensor networks(2010) Kamath, G.M.; Shekar, Y.; Abhijith, K.G.; Sripati, U.; Kulkarni, M.Wireless Sensor Networks generally operate under severe energy constraints. In many cases, the networks are star connected with battery-powered nodes sensing data and sending it to a centrally-powered base station, whose energy constraints are more fore-bearing than that of the nodes. In this paper, an approach for energy efficient communication by using different channel codes on the base-station to node link (downlink) and node to base-station link (uplink) is proposed and analysed for such a network topology. This is in effect shifting complexity from the node to the base station while continuing to have the same BER performance. Also the use of more energy efficient modulation schemes are explored. ©2010 IEEE.Item Exploring the effectiveness of social capabilities and goal alignment in computer supported collaborative learning(2010) Ai, H.; Kumar, R.; Nguyen, D.; Nagasunder, A.; Rosé, C.P.In this study, we describe a conversational agent designed to support collaborative learning interactions between pairs of students. We describe a study in which we independently manipulate the social capability and goal alignment of the agent in order to investigate the impact on student learning outcomes and student perceptions. Our results show a significant interaction effect between the two independent variables on student learning outcomes. While there are only a few perceived differences related to student satisfaction and tutor performance as evidenced in the questionnaire data, we observe significant differences in student conversational behavior, which offer tentative explanations for the learning outcomes we will investigate in subsequent work. © 2010 Springer-Verlag.Item Implementation of stream cipher system based on representation of integers in residue number system(2010) Aithal, G.; Bhat, K.N.H.; Sripathi, U.Residue Number Systems (RNS) based on Chinese Remainder Theorem (CRT) permits the representation of large integers in terms of combinations of smaller ones. The set of all integers from 0 to M-1 with RNS representation and component wise modular addition and multiplication constitutes direct sum of smaller commutative rings. Encryption and decryption algorithm based on the properties of direct sum of smaller rings offers distinct advantages over decimal or fixed radix arithmetic. In this paper representation of integer using RNS, is successfully utilized in additive, multiplicative and affine stream cipher systems. The property of the cipher system based on RNS number system allow speeding up the encryption / decryption algorithm, reduce the time complexity and provides immunity to side channel, algebraic, and known plain text attacks. In this paper, the characteristics of additive, multiplicative and affine stream cipher systems, the key generation, and encryption and decryption based on RNS number system representation are discussed. ©2010 IEEE.Item A phenomic approach to genetic algorithms for reconstruction of gene networks(2010) D'Souza, R.G.L.; Chandra Sekaran, K.C.; Kandasamy, A.Genetic algorithms require a fitness function to evaluate individuals in a population. The fitness function essentially captures the dependence of the phenotype on the genotype. In the Phenomic approach we represent the phenotype of each individual in a simulated environment where phenotypic interactions are enforced. In reconstruction type of problems, the model is reconstructed from the data that maps the input to the output. In the phenomic algorithm, we use this data to replace the fitness function. Thus we achieve survival-of-the- fittest without the need for a fitness function. Though limited to reconstruction type problems where such mapping data is available, this novel approach nonetheless overcomes the daunting task of providing the elusive fitness function, which has been a stumbling block so far to the widespread use of genetic algorithms. We present an algorithm called Integrated Pheneto-Genetic Algorithm (IPGA), wherein the genetic algorithm is used to process genotypic information and the phenomic algorithm is used to process phenotypic information, thereby providing a holistic approach which completes the evolutionary cycle. We apply this novel evolutionary algorithm to the problem of elucidation of gene networks from microarray data. The algorithm performs well and provides stable and accurate results when compared to some other existing algorithms. © 2010 Springer-Verlag Berlin Heidelberg.Item Fuzzy logic based coordinated voltage regulation method for distribution system with multiple synchronous generators(2010) Gaonkar, D.N.; Pillai, G.N.The continued interest in the distributed generation (DG) sources in recent years is leading to the growth of a number of generators connected to distribution networks. The steady-state voltage rise resulting from the connection of these generators can be a major obstacle at the lower voltage levels. Present network design practice is to limit the generator capacity to a level at which the upper voltage limit is not exceeded. This reduces the efficiency of DG system. This paper proposes a coordinated voltage control scheme using fuzzy logic based power factor controller, for distribution network with multiple Distributed generation systems. In the proposed scheme individual generators participate in voltage regulation of the distribution system, based on their participation factor determined using sensitivity analysis. The simulation results presented in the paper show the effectiveness of the method. © 2010 IEEE.Item Discovery of weighted association rules mining(2010) Kumar, P.; Ananthanarayana, V.S.Mining of association rules for basket databases, has been investigated by [1] [3] [4], [9], [12], etc. Most of these works focus on mining binary association rules, i.e, most of the association rules mining algorithms to discover frequent itemsets do not consider the quantity in which items have been purchased. This paper discusses an efficient method for discovering a weighted association rules from a large volumes of data in a single scan of the database. The data structure used here is called Weighted Tree. We found that this algorithm is more efficient than Cai's Algorithm. ©2010 IEEE.