(SoE) School of Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

The Location Based Services (LBS) seem to be the next revolution on small computing handheld devices in terms of location aware advertising, security alerts, news updates, disaster management, geo-fencing, buddy-findings, gaming, criminal investigations, turn-by-turn navigation and so on. In today's scenario there is an explosion of technologies to communicate with mobile, connected devices and sensors. In this paper we are presenting a literature survey of LBS that includes the architecture of the LBS ecosystem, the key market players, and the latest trends in LBS development. Finally, the broad research areas such as location determination techniques, geo-sensor networks, and location based natural queries, location privacy and authorization, geo-social networks, LBS QoS, and Location Based Recommender Systems (LBRS) have been studied and presented briefly. © 2011 Springer-Verlag Berlin Heidelberg.

World University root node

Computer Science and Engineering

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

A survey on LBS: System architecture, trends and broad research areas

The advent of e-commerce has brought about a radical change in the process of auctions. This has given bidders flexibility to try and get best possible deals by participating in multiple auctions which are happening for the same item in overlapping times. Such scenario will change the bidding strategies being used by humans or agents. One of the most important points for deciding the strategy of bidding in multiple auctions is to find out the expected end price of the auctions that is based on the market dynamics which changes on various dynamic parameters such as number of bidders, current price, and time left for closure of auction etc. In this paper, learning of market dynamics is proposed by using genetic algorithm. A function is evolved based on environmental parameters which will take these parameters along with current bid value as input and returns the expected end price. The performance analysis of the expected end price is done for the solution proposed. The required data is generated by simulating an electronic marketplace environment which consists of multiple overlapping auctions of the same item with multiple bidders participating in them. The total number of bidders are not constant but increase in the environment based on defined bidder rate. The performance of the proposed prediction method is measured by comparing predicted end price with the actual end price. This measurement takes place at predefined time intervals and at different behaviors of dynamic parameters. The results captured during the experiment are empirically evaluated through statistical models like multivariate ANOVA (Analysis of Variance) and Independent Samples t Test. © 2011 by IJAI.

International Journal of Artificial Intelligence

Bidding strategy based on market dynamics

The tilting phenomenon may lead to a catastrophic failure, such as an interturn fault in transformers, under the action of axial short-circuit electromagnetic forces. In this paper, first, a state-space approach has been used to determine the eigenvalues of various winding configurations used in practice by assuming a small value of tilt angle up to 10°. These eigenvalues decide the critical tilting forces and the natural frequencies of windings. The four cases involving disk, layer, helical windings (all these with strip conductor), and layer winding with continuously transposed cable conductor have been analyzed. Further, initial critical tilt angles are determined for various magnitudes of the axial force in a typical 5-MVA transformer. © 2011 IEEE.

Electrical Engineering

IEEE Transactions on Power Delivery

Eigenvalue analysis for investigation of tilting of transformer winding conductors under axial short-circuit forces

We report a systematic study of structural, optical, and magnetic measurements on Zn0.9Cd0.1S:yCo films in the concentration range of 0.005 ≤ y ≤ 0.05 M using pulsed laser deposition technique. Structure, composition analysis, and optical measurements revealed that Cobalt is incorporated into the lattice, as Co2+ substituting Zn 2+ ions, forming a solid solution with cubic structure instead of Cobalt precipitates. Low temperature magnetization measurements reveal a paramagnetic behavior. UV-vis measurements showed a red shift with respect to undoped sample in the energy band gap with increasing Cobalt concentration. Photoluminescence measurements shows ∼ 300 times increase in intensity by Cobalt doping in Zn0.9Cd0.1S matrix. © 2011 Elsevier B.V.

Thin Solid Films

Study of the physical properties of PLD grown cobalt doped nanocrystalline Zn0.9Cd0.1S thin films

We have examined the interactions of gaseous pollutants and primary aerosols that can produce secondary inorganic aerosols. The specific objective was to estimate degradation rates of precursor gases (NH3, NO2 and SO2) responsible for formation of secondary inorganic aerosols. A Teflon-based outdoor environmental chamber facility (volume 12.5m3) was built and checked for wall losses, leaks, solar transparency and ability to simulate photochemical reactions. The chamber was equipped with state-of-the-art instrumentation to monitor concentration-time profiles of precursor gases, ozone, and aerosol. A total of 14 experimental runs were carried out for estimating the degradation of precursor gases. The following initial conditions were maintained in the chamber: NO2=246±104ppb(v), NH3=548±83ppb(v), SO2=238±107ppb(v), O3=50±11ppb(v), PM2.5 aerosol=283438±60524 No./litre. The concentration-time profile of gases followed first-order decay and were used for estimating degradation rates (NO2=0.26±0.15h-1, SO2=0.31±0.17h-1, NH3=0.35±0.21h-1). We observed that degradation rates showed a statistical significant positive correlation (at 5% level of significance) with the initial PM2.5 levels in the chamber (coefficient of correlation: 0.63 for NO2; 0.62 for NH3 and 0.51 for SO2), suggesting that the existing surface of the aerosol could play a significant role in degradation of precursor gases. One or more gaseous species can be adsorbed on to the existing particles and these may undergo heterogeneous or homogeneous chemical transformation to produce secondary inorganic aerosols. Through correlation analysis, we have observed that degradation rates of precursor gases were dependent on initial molar ratio of (NH3)/(NO2+SO2), indicative of ammonia-rich and ammonia-poor situations for eventual production of ammonium salts. © 2011 Elsevier Ltd.

Civil Engineering

Atmospheric Environment

Degradation of SO2, NO2 and NH3 leading to formation of secondary inorganic aerosols: An environmental chamber study

In this paper, We extended our previous work of QR-RLS based MIMO(Multiple input Multiple output) channel estimation to Mobile Wimax 802.16m system. Mobile wimax system provides high data rate, also fulfills user's requirement like VOD(Video on demand)at very high vehicle speed and also provides better cell coverage area. Channel estimation is crucial part to achieve this goals especially in fast fading environment. Generally, Mobile Wimax systems uses Preamble and Pilots for channel estimation purpose. In the proposed method both preamble and pilots are jointly used for robust channel estimation. At First, QR-RLS Estimator uses Preamble for coarse channel estimation at start of every frame. Once the coarse channel is estimated, then pilots (scattered throughout time-frequency grid) are jointly used with the coarse channel component to derive the channel fading rate. This fading rate is then used to finely estimate the channel at pilot as well as data subcarrier. Thus robust estimation results without adding any overhead. Jointly estimated channel is then used with QR-LRL based data detection, where hard decision values are calculated. Simulation results are shown under various slow-fast channel fading conditions. Results are compared with pilot based channel estimation with LS(least square) interpolation, which shows that joint coarse-Fine estimation gives better performance. © 2011 IEEE.

GLOBECOM - IEEE Global Telecommunications Conference

A joint QR-LS based coarse-fine channel estimation and QR-LRL detection for mobile WiMAX 802.16m

We have proposed a hybrid SVM based decision tree to speedup SVMs in its testing phase for binary classification tasks. While most existing methods addressed towards this task aim at reducing the number of support vectors, we have focused on reducing the number of test datapoints that need SVM's help in getting classified. The central idea is to approximate the decision boundary of SVM using decision trees. The resulting tree is a hybrid tree in the sense that it has both univariate and multivariate (SVM) nodes. The hybrid tree takes SVM's help only in classifying crucial datapoints lying near decision boundary; remaining less crucial datapoints are classified by fast univariate nodes. The classification accuracy of the hybrid tree is guaranteed by tuning a threshold parameter. Extensive computational comparisons on 19 publicly available datasets indicate that the proposed method achieves significant speedup when compared to SVMs, without any compromise in classification accuracy. © 2010 Elsevier Ltd. ALL rights reserved.

Pattern Recognition

A hybrid SVM based decision tree

To investigate the potential role of ammonia in ion chemistry of PM2.5 aerosol, measurements of PM2.5 (particulate matter having aerodynamic diameter&lt;2.5μm) along with its ionic speciation and gaseous pollutants (sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3) and nitric acid (HNO3)) were undertaken in two seasons (summer and winter) of 2007-2008 at four sampling sites in Kanpur, an urban-industrial city in the Ganga basin, India. Mean concentrations of water-soluble ions were observed in the following order (i) summer: SO42- (26.3μgm-3)&gt;NO3- (16.8)&gt;NH4+ (15.1)&gt;Ca2+ (4.1)&gt;Na+ (2.4)&gt;K+ (2.1μgm-3) and (ii) winter: SO42- (28.9μgm-3)&gt;NO3- (23.0)&gt;NH4+ (16.4)&gt;Ca2+(3.4)&gt;K+(3.3)&gt;Na+ (3.2μgm-3). The mean molar ratio of NH4+ to SO42- was 2.8±0.6 (mostly &gt;2), indicated abundance of NH3 to neutralize H2SO4. The excess of NH4+ was inferred to be associated with NO3- and Cl-. Higher sulfur conversion ratio (Fs: 58%) than nitrogen conversion ratio (Fn: 39%) indicated that SO42- was the preferred secondary species to NO3-. The charge balance for the ion chemistry of PM2.5 revealed that compounds formed from ammonia as precursor are (NH4)2SO4, NH4NO3 and NH4Cl. This study conclusively established that while there are higher contributions of NH4+, SO42- to PM2.5 in summer but for nitrates (in particulate phase), it is the winter season, which is critical because of low temperatures that drives the reaction between ammonia and HNO3 in forward direction for enhanced nitrate formation. In summary, inorganic secondary aerosol formation accounted for 30% mass of PM2.5 and any particulate control strategy should include optimal control of primary precursor gases including ammonia. © 2010 Elsevier B.V.

Science of the Total Environment

Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment

We present a general approach for designing approximation algorithms for a fundamental class of geometric clustering problems in arbitrary dimensions. More specifically, our approach leads to simple randomized algorithms for the k-means, k-median and discrete k-means problems that yield (1+ε) approximations with probability ≥ 1/2 and running times of O(2(k/ε)O(1)dn). These are the first algorithms for these problems whose running times are linear in the size of the input (nd for n points in d dimensions) assuming k and ε are fixed. Our method is general enough to be applicable to clustering problems satisfying certain simple properties and is likely to have further applications. © 2010 ACM.

Fulltext

Journal of the ACM

Linear-time approximation schemes for clustering problems in any dimensions

Web services provide a promising solution to an age old need of fast and flexible information sharing among people and businesses. Selection of web service has become a tedious job because of the increasing number of service providers providing services with similar functionality. Service registries are becoming very large preventing users from discovering desired service. Sometimes service users may not be aware of services that can be most beneficial to them. Therefore, a framework for selection of web service that can meet the user's specific requirements is needed. In this work, we have proposed a personalized web service recommender system that will be very useful to the user in finding web service matching his/her needs. A recommender system helps product/service user to deal with information overload and provides personalized recommendation to them. There have been a few web service recommendation system in past, but most of them are either content based or collaborative filtering based recommendation. But all of these approaches have their own limitations. In our work we have proposed a web service recommender system based on hybrid technique which takes advantages of collaborative filtering based, content based and knowledge based approaches and minimize there individual limitations. ©2010 IEEE.