(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

Mechanical Engineering

World University root node

Ocean Engineering

Erratum: A 3D fully coupled analysis of nonlinear sloshing and ship motion (Ocean Engineering (2012) 39 (1-13) DOI: 10.1016/j.oceaneng.2011.09.015)

In this paper, we study the important problems of message routing, sorting, and selection in a radio network. A radio network consists of stations where each station is a hand-held device. We consider a single-hop radio network where it is assumed that each station is within the transmission range of every other station. Let RN(p,k) stand for a single-hop network that has p stations and k communication channels. The best known prior algorithm for sorting takes 4nk+o(nk) broadcast rounds on a RN(p,k). In this paper, we present a randomized algorithm that takes only 3nk+o(nk) broadcast rounds with high probability. For the selection problem, we present a randomized selection algorithm that takes O(pk) rounds on a RN(p,k) with high probability. The best known prior algorithms for the np-relations routing problem take nearly 2nk time slots (i.e., broadcast rounds). An important open question has been if there exist algorithms that take only close to nk time slots. Note that a trivial lower bound for routing is nk. The existence of such algorithms will be highly relevant, especially in emergencies and time-critical situations. In this paper, we answer this question by presenting a randomized algorithm that takes nearly nk rounds on the average. We also present a deterministic algorithm that takes nearly nk rounds. These routing algorithms are also shown to be energy efficient. © 2012 Elsevier Inc. All rights reserved.

Computer Science and Engineering

Journal of Parallel and Distributed Computing

Communication and energy efficient routing protocols for single-hop radio networks

Mumbai city is the financial capital of India and is fifth most densely populated city in the world. Seismic soil liquefaction is evaluated for Mumbai city in terms of the factors of safety against liquefaction (FS) along the depths of soil profiles for different earthquakes with 2% probability of exceedance in 50 yr using standard penetration test (SPT)-based simplified empirical procedure. This liquefaction potential is evaluated at 142 representative sites in the city using the borehole records from standard penetration tests. Liquefaction potential index (LPI) is evaluated at each borehole location from the obtained factors of safety (FS) to predict the potential of liquefaction to cause damage at the surface level at the site of interest. Spatial distribution of soil liquefaction potential is presented in the form of contour maps of LPI values. As the majority of the sites in the city are of reclaimed land, the vulnerability of liquefaction is observed to be very high at many places. ©2012 Author(s).

Civil Engineering

Fulltext

Natural Hazards and Earth System Science

Assessment of liquefaction potential index for Mumbai city

<p>A plasma cathode electron (PCE) gun has capabilities for generating high-current, broad, and focused beams for plasma-assisted microwave sources. A pseudospark-based hollow cathode PCE gun has been designed and developed for microwave generation which is operated in argon atmosphere. An analysis of the electron beam profile inside the drift space at different operating conditions has been carried out. This has been performed at several axial and radial locations inside the drift space which shows coherent phases of beam profiles in radial direction. The focusing and defocusing points in axial direction are also obtained. The beam current at different axial location for different applied voltages has been estimated. The obtained beam current is in close agreement with the beam current estimated by the particle-in-cell simulation code for the same geometry.</p>

Electrical Engineering

Journal of Theoretical and Applied Physics

Development of low-pressure high-current plasma cathode electron gun and use of associated techniques

Electron beam analysis of pseudospark sourced electron gun

Pseudospark discharge based plasma cathode has capability to provide high current density electron beam during discharge process. In this paper an effort has been made to simulate the breakdown processes in the pseudospark discharge based plasma cathode electron gun. The two-dimensional plasma simulation codes VORPAL and OOPIC-Pro have been used and results are compared. The peak discharge current in the plasma cathode electron gun is found to be dependent on aperture size, hollow cathode dimensions, anode voltage and seed electrons energy. The effect of these design parameters on the peak anode current has been analysed by both the codes and results matches well within 10% variation. For the seed electron generation an electron beam trigger source is used to control the discharge process in the hollow cathode cavity. The time span of trigger source has been varied from 1-100 ns to analyze the effect on the peak anode current. © Published under licence by IOP Publishing Ltd.

Journal of Physics: Conference Series

Comparative simulation studies of plasma cathode electron (PCE) gun

This study investigates the coupling effects of six degrees of freedom in ship motion with fluid oscillation inside a three-dimensional rectangular container using a novel time domain simulation scheme. During the time marching, the tank-sloshing algorithm is coupled with the vessel-motion algorithm so that the influence of tank sloshing on vessel motions and vice versa can be assessed. Several factors influencing the dynamic behavior of tankliquid system due to moving ship are also investigated. These factors include container parameters, environmental settings such as the significant wave height, current velocity as well as the direction of wind, wave and flow current acting on the ship. The nonlinear sloshing is studied using a finite element model whereas nonlinear ship motion is simulated using a hybrid marine control system. Computed roll response is compared with the existing results, showing fair agreement. Although the two hull forms and the sea states are not identical, the numerical result shows the same trend of the roll motion when the anti-rolling tanks are considered. Thus, the numerical approach presented in this paper is expected to be very useful and realistic in evaluating the coupling effects of nonlinear sloshing and 6-DOF ship motion. © 2011 Elsevier Ltd All rights reserved.

A 3D fully coupled analysis of nonlinear sloshing and ship motion

The homogeneous boundary value problem arising in the propagation of electromagnetic waves guided by an open tape helix modelled to be of infinitesimal tape thickness and infinite tape-material conductivity is shown to be inherently ill posed. It is demonstrated how the ill posed problem may be regularised using the mollification method. The regularised boundary value problem is then solved to yield the approximate dispersion equation which takes the form of the solvability condition for an infinite system of linear homogeneous algebraic equations viz., the determinant of the infinite-order coefficient matrix is zero. For the numerical computation of the dispersion characteristic, all the entries of the symmetrically truncated version of the coefficient matrix are estimated by summing an adequate number of the rapidly converging (after regularisation) series for them. The tape-current distribution is estimated from the null-space vector of the truncated coefficient matrix corresponding to a specified root of the dispersion equation. A comparison of the numerical results with those for the anisotropically conducting model (that neglects the component of the tape-current density perpendicular to the winding direction) of the tape helix reveals that the propagation characteristic computed on the basis of the anisotropically conducting model could be substantially in error even for moderately wide tapes. © 2012 The Institution of Engineering and Technology.

IET Microwaves, Antennas and Propagation

Perfectly conducting tape-helix model for guided electromagnetic wave propagation

A method based on the application of Kötter's equation is proposed to evaluate active earth pressure on an inclined wall retaining horizontal cohesionless backfill with uniform surcharge. This method considers only the effect of surcharge for the analysis. It is successfully used to evaluate the magnitude and point of application of reaction on the failure surface. The coefficient of active earth pressure and point of application of the active thrust are computed for different combinations of soil and wall properties and the results are presented in dimensionless forms. A fairly good comparison is seen with the available solutions.

Electronic Journal of Geotechnical Engineering

Active earth pressure on an inclined wall with horizontal cohesionless backfill due to surcharge effect

In this paper we present a cache-oblivious framework for randomized divide and conquer algorithms on the multicore model with private cache. We first derive an O( p n log n + log n log log n) expected parallel depth algorithm for sorting n numbers with expected O( B n log M n) cache misses where p,M and B respectively denote the number of processors, the size of an individual cache memory and the block size respectively. Although similar results have been obtained recently for sorting [4], we feel that our approach is simpler and general and we apply it to obtain an algorithm for 3D convex hulls with similar bounds. We also present a simple randomized processor allocation technique without the explicit knowledge of the number of processors that is likely to find additional applications in resource oblivious environments. A longer version of this paper is available at [8]. Copyright is held by the author/owner(s).