(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

In power systems the primary requirement is to find a rigorous approach to suppress the harmonics and ultimately extract the fundamental frequency component. The method presented enables the FIR filter design satisfying specific frequency characteristics with auxiliary constraints. The job of design is converted to an optimization problem with the constraint using standard mean square criterion. The strategy behind detection is to optimize the destined constraint function and to minimize the mean square error. The performance of the advised technique is compared with that of LMS and linear optimal filters. Experimental results both in ideal and noisy condition associated with the three methods are given.

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Electrical Engineering

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Constrained filter-based fundamental frequency tracking in power systems

In this paper, QR-RLS based adaptive channel TEQ(Time Domain Equalizer) to make the OFDM systems robust for delay spreads exceeding the CP(cyclic prefix) is presented. The performance of the proposed method is compared with standard LMS and exponentially weighted RLS based TEQ, in terms of computational complexity and BER. QR decomposition using Givens transformation results in better computational complexity compared to standard RLS and QRD based on gram schmidt orthogonalization process. The simulation results show that this method gives better results as compared to the aforementioned methods. © 2008 IEEE.

Proceedings of ICSCN 2008 - International Conference on Signal Processing Communications and Networking

QR-RLS based adaptive channel TEQ for OFDM Wireless LAN

The Parallel Disks Model (PDM) has been proposed to alleviate the I/O bottleneck that arises in the processing of massive data sets. Sorting has been extensively studied on the PDM model due to the fundamental nature of the problem - several asymptotically optimal algorithms are known for sorting. Although randomization has been frequently exploited, most of the prior algorithms suffer from complications in memory layouts, implementation, restrictions in range of parameters, and laborious analysis. In this paper, we present a randomized mergesort algorithm based on a simple idea that sorts using an asymptotically optimal number of I/O operations with high probability and has all of the desirable features for practical implementation. In the second part of the paper, we also present several novel algorithms for sorting on the PDM that take only a small number of passes through the data. Recently, considerable interest has been shown by researchers in developing algorithms for problem sizes of practical interest and we are able to obtain several improvements and simplification, in particular for random input. © 2008 IEEE.

Fulltext

IEEE Transactions on Computers

Optimal and practical algorithms for sorting on the PDM

Multiple memory models have been proposed to capture the effects of memory hierarchy culminating in the I-O model of Aggarwal and Vitter (Commun. ACM 31(9):1116-1127, [1988]). More than a decade of architectural advancements have led to new features that are not captured in the I-O model-most notably the prefetching capability. We propose a relatively simple Prefetch model that incorporates data prefetching in the traditional I-O models and show how to design optimal algorithms that can attain close to peak memory bandwidth. Unlike (the inverse of) memory latency, the memory bandwidth is much closer to the processing speed, thereby, intelligent use of prefetching can considerably mitigate the I-O bottleneck. For some fundamental problems, our algorithms attain running times approaching that of the idealized random access machines under reasonable assumptions. Our work also explains more precisely the significantly superior performance of the I-O efficient algorithms in systems that support prefetching compared to ones that do not. © 2008 Springer Science+Business Media, LLC.

Journal of Supercomputing

Combating I-O bottleneck using prefetching: Model, algorithms, and ramifications

Electromagnetic levitation system (EMLS) is inherently unstable and strongly nonlinear in nature. A cascade lead compensation control scheme utilizing inner current loop and outer position loop has been designed and implemented for stabilization of a single magnet based single axis levitation system. The prototype has been successfully tested and stable levitation has been demonstrated at the desired operating gap. The dynamic performance of the controller has been studied experimentally by applying different disturbance inputs (square wave, sinusoidal etc.) with increasing magnitudes and frequencies. The effect of different basic parameters of the levitation system on the performance of the designed controller has also been observed. ©2008 IEEE.

PECon 2008 - 2008 IEEE 2nd International Power and Energy Conference

A practical study on the dynamic performance of a controller for an electromagnetic levitation system

We present a detailed understanding of filamentation, through rigorous mixed-mode 3D simulation in a nano-meter scale drainextended NMOS (DE-NMOS). Localization is first triggered in the 2D plane due to regenerative turn-on of the parasitic bipolar. 3D Simulations performed by adding width along the Z-axis (i.e., W) show a very prominent localization effect, which leads to electro-thermal runaway in the DE-NMOS and causes an irreversible damage. © 2008 IEEE.

IEEE International Reliability Physics Symposium Proceedings

3D device modeling of damage due to filamentation under an ESD event in nanometer scale drain extended NMOS (DE-NMOS)

Using a two-color laser technique, we have measured the temperature dependence of the second- and third-order optical nonlinear susceptibilities, χ (2) and χ (3), at the Si/ SiO2 interface. A laser beam at 540 nm directed normal to the surface was used to pump electrons from the silicon valence band to trap states on the SiO2 surface leaving the holes at or near the interface thus creating a capacitance electric field. A second beam of wavelength 800 nm incident at 45° on the same spot resulted in a second-harmonic signal whose intensity was related to the varying interfacial electric field. We find that the photoinduced electric field is temperature independent since the charge distributions remain unchanged after pumping and both χ (2) and χ (3) increase as the temperature increases. © 2008 The American Physical Society.

Physical Review B - Condensed Matter and Materials Physics

Temperature-dependent second- and third-order optical nonlinear susceptibilities at the Si/ SiO2 interface

We propose algorithms to extract groups of meaningful image level lines using Helmholtz perception principle. In this paper, the meaningfulness refers to the segmentation of circular and rectangular shapes in an image. We propose an objective assessment of meaningfulness of an image level line when the level line takes the shape of circle or rectangular segment. We have shown that a logical threshold in the meaningfulness value segments images from a variety of applications. © 2008 IEEE.

Computer Science and Engineering

Proceedings - 6th Indian Conference on Computer Vision, Graphics and Image Processing, ICVGIP 2008

Segmentation of circular and rectangular shapes in an image using helmholtz principle

Tert-butyl peroxybenzoate (TBPB) is one of the sensitive and hazardous chemicals which have been popularly employed in petrifaction industries in the past. This study attempted to elucidate its unsafe characteristics and thermally sensitive structure so as to help prevent runaway reactions, fires or explosions in the process environment. We employed differential scanning calorimetry (DSC) to assess the kinetic parameters (such as exothermic onset temperature (T 0), heat of reaction (ΔH), frequency factor (A)), and the other safety parameters using four different scanning rates (1, 2, 4 and 10°C min-1) combined with curve-fitting method. The results indicated that TBPB becomes very dangerous during decomposition reactions; the onset temperature and reaction heat were about 100°C and 1300 J g-1, respectively. Through this study, TBPB accidents could be reduced to an accepted level with safety parameters under control. According to the findings in the study and the concept of inherent safety, TBPB runaway reactions could be thoroughly prevented in the relevant plants. © 2008 Springer Science+Business Media, LLC.

Chemical Engineering

Journal of Thermal Analysis and Calorimetry

Runaway reaction on tert-butyl peroxybenzoate by DSC tests

A simple scheme that allows fast control of induction motor torque has been presented. It is different from the conventional direct torque control (DTC) scheme in the sense that it does not use the popular DTC switching table. Also, it does not require use of any online fast computing device like a microprocessor, personal computer (PC) or digital signal processor (DSP). The proposed scheme uses only commonly used discrete hardware components for its implementation. The experimental results obtained from the hardware realization of the proposed scheme are found to be in close agreement with the simulation results. © 2007 Elsevier Ltd. All rights reserved.