(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

Let G(V, E) be an undirected weighted graph with |V| = n, and |E| = m. A t-spanner of the graph G(V, E) is a sub-graph G(V, Es) such that the distance between any pair of vertices in the spanner is at most t times the distance between the two in the given graph. A 1963 girth conjecture of Erdos implies that Ω(n1+1/k) edges are required in the worst case for any (2k - 1)-spanner, which has been proved for k = 1, 2, 3, 5. There exist polynomial time algorithms that can construct spanners with the size that matches this conjectured lower bound, and the best known algorithm takes O(mn1/k) expected running time. In this paper, we present an extremely simple linear time randomized algorithm that constructs (2k - 1)-spanner of size matching the conjectured lower bound. Our algorithm requires local information for computing a spanner, and thus can be adapted suitably to obtain efficient distributed and parallel algorithms. © Springer-Verlag Berlin Heidelberg 2003.

World University root node

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

A simple linear time algorithm for computing a (2k - 1)-spanner of O(n1+1/k) size in weighted graphs

In this paper a study on the references is performed. An algorithm has been developed to find the referent of implicit anaphora. A representation of noun storage in knowledgebase is devised. The algorithm is designed to identify the presence of implicit anaphora, and is implemented in C++. A prototype lexicon has been designed. The algorithm worked well for test inputs. The results are presented. © 2003 Taylor & Francis Group, LLC.

Computer Science and Engineering

IETE Journal of Research

Pronominal referent interpretation system for english text

Inherently safer design (ISD) concepts have been with us for over two decades since their elaboration by Kletz [Chem. Ind. 9 (1978) 124]. Interest has really taken off globally since the early nineties after several major mishaps occurred during the eighties (Bhopal, Mexico city, Piper-alfa, Philips Petroleum, to name a few). Academic and industrial research personnel have been actively involved into devising inherently safer ways of production. The regulatory bodies have also shown deep interest since ISD makes the production safer and hence their tasks easier. Research funding has also been forthcoming for new developments as well as for demonstration projects. A natural question that arises is as to how to measure ISD characteristics of a process? Several researchers have worked on this [Trans. IChemE, Process Safety Environ. Protect. B 71 (4) (1993) 252; Inherent safety in process plant design, Ph.D. Thesis, VTT Publication Number 384, Helsinki University of Technology, Espoo, Finland, 1999; Proceedings of the Mary Kay O'Connor Process Safety Center Symposium, 2001, p. 509]. Many of the proposed methods are very elegant, yet too involved for easy adoption by the industry which is scared of yet another safety analysis regime. In a recent survey [Trans. IChemE, Process Safety Environ. Prog. B 80 (2002) 115], companies desired a rather simple method to measure ISD. Simplification is also an important characteristic of ISD. It is therefore desirable to have a simple ISD measurement procedure. The ISD measurement procedure proposed in this paper can be used to differentiate between two or more processes for the same end product. The salient steps are: Consider each of the important parameters affecting the safety (e.g., temperature, pressure, toxicity, flammability, etc.) and the range of possible values these parameters can have for all the process routes under consideration for an end product. Plot these values for each step in each process route and compare. No addition of values for disparate hazards (temperature, pressure, inventory, toxicity, flammability, etc.) is being suggested to derive an overall ISD index value since that conceals the effects of different parameters. Further, addition of numbers with different units (°C for temperature, atm/bar for pressure, t for inventory, etc.) is inappropriate in scientific sense. The proposed approach has a major advantage of expanding consideration in future to incorporate economic, regulatory, pollution control and worker health aspects, as well as factors such as the experience one has or 'the comfort level' one feels with each of the processes under consideration. Additionally, it would also guide the designers and decision makers into affecting specific changes in the processes to reduce the unsafe features. We demonstrate our simple approach by using the example of six routes to make methyl methacrylate as documented by Edwards and Lawrence [Trans. IChemE, Process Safety Environ. Protect. B 71 (4) (1993) 252; Quantifying inherent safety of chemical process routes, Ph.D. Thesis, Loughborough University, Loughborough, UK, 1996] and show that the decision could well have been different if addition of disparate hazards had not been done. © 2003 Elsevier B.V. All rights reserved.

Chemical Engineering

Journal of Hazardous Materials

A simple graphical method for measuring inherent safety

The Dow Fire and Explosion Index (F&EI) is universally used in evaluating the hazard category of a process plant, area of exposure, expected losses in case of fire and explosion, etc. In the current procedure, the effects of the loss control measures (LCMs) on the F&EI value are not taken into account. This makes the plant look more hazardous, makes it more spread out, requires more elaborate emergency measures and alarms the public and the civil administration more than is necessary. It also affects the insurance premium. We suggest taking the effects of the LCMs into account in the F&EI value. We call this the 'Offset F&EI' value. It favorably affects all the above items, and other related ones. To do this, we have developed the relevant equations and have proved the efficacy of the Offset F&EI by means of an example. © 2003 Elsevier Science Ltd. All rights reserved.

Journal of Loss Prevention in the Process Industries

Calculation of Fire and Explosion Index (F and EI) value for the Dow Guide taking credit for the loss control measures

The recent publication by the US Chemical Safety Board (CSB) concerning its findings on the Concept Sciences Inc. (CSI) incident involving hydroxylamine (HA) has raised issues with regard to safe production of HA. This CSI incident was followed by another incident that destroyed the Nissin Chemical HA plant in Japan, and today BASF is the sole commercial producer of HA. HA is an important solvent in the pharmaceutical industry and is used as an etching agent in the semi-conductor industry. This paper discusses a Quantitative Risk Assessment of a generic HA production plant, which integrates the findings of the CSB report and the knowledge of potential HA reactivity hazards based on research at the Mary Kay O'Connor Process Safety Center. The intent is to highlight safety concerns and major risk factors in the production and handling of HA and to provide risk assessment guidelines for potential manufacturers. These guidelines are also applicable to the production strategies for other hazardous chemicals. © 2003 Elsevier Science Ltd. All rights reserved.

Reliability Engineering and System Safety

Hydroxylamine production: Will a QRA help you decide?

With ever-increasing applications of microelectromechanical systems (MEMS), techniques to measure their micro-movements have become important. This paper presents a new method for amplitude measurement of a vibrating silicon diaphragm using Talbot interferometry. A silicon wafer glued to a speaker diaphragm was initially used as a periodically vibrating test sample. A sinusoidal voltage was applied to the speaker to induce vibrations whose amplitude was measured as a function of frequency. The same technique has further been extended for amplitude measurement of vibration of mechanically excited silicon diaphragm, fabricated using well known "bulk micromachining technology".

Electrical Engineering

Proceedings of SPIE - The International Society for Optical Engineering

Amplitude measurement of vibrating silicon using talbot interferometry

We propose Fair Adaptive Bandwidth Allocation (FABA), a buffer management discipline that ensures a fair bandwidth allocation amongst competing flows even in the presence of non-adaptive traffic. FABA is a rate control based active queue management discipline that provides explicit fairness and can be used to partition bandwidth in proportion to pre-assigned weights. FABA is well-suited for allocation of bandwidth to aggregate flows as required in the differentiated services framework. We study and compare FABA with other well known queue management disciplines and show that FABA ensures fair allocation of bandwidth across a much wider range of buffer sizes at a bottleneck router. FABA uses randomization and has an O(1) average time complexity, and, is therefore scalable. The space complexity of the proposed algorithm is O(B) where B is the buffer size at the bottleneck router. We argue that though FABA maintains per active-flow state, through O(1) computation, reasonably scalable implementations can be deployed which is sufficient for network edges and ISPs. © Springer-Verlag Berlin Heidelberg 2002.

Fair adaptive bandwidth allocation: A rate control based active queue management discipline

We present a new scheme for storing a planar graph in external memory so that any online path can be traversed in an I-O efficient way. Our storage scheme significantly improves the previous results for planar graphs with bounded face size. We also prove an upper bound on I-O efficiency of any storage scheme for well-shaped triangulated meshes. For these meshes, our storage scheme achieves optimal performance.

Fulltext

Algorithmica (New York)

Planar graph blocking for external searching

The barrier to the industrial implementation of optical interconnects on an IC, center around the fabrication of optical elements on wafers through conventional Si processes. It has been shown previously that Si-based p+-n+ diodes operating in avalanche breakdown mode emit light in the 400-900 nm range. This paper focuses on demonstrating that these Si-based light emitters can operate in the GHz range and provide reliable operation. The modulation of the light emitter was verified using a Hamamatsu streak camera for operation up to 50 psec of pulse width signals. The reliability of these emitters was verified through accelerated AC, DC, and temperature stressing. None of the stressing methods altered the total junction light emission. Low current DC stressing, however, did cause reversible light coalescence. A model has been developed to explain this phenomena. © 2002 IEEE.

Proceedings of the IEEE 2002 International Interconnect Technology Conference, IITC 2002

High speed, high reliability Si-based light emitters for optical interconnects

We present improved reductions of the nearest neighbor searching problem to Point Location in Balls by constructing linear size Approximate Voronoi Diagrams while maintaining the logarithmic search time. We do this first by simplifying the construction of Har-Peled[9] that reduces the number of balls generated by a logarithmic factor to O(n log n). We further reduce the number of balls by a new hierarchical decomposition scheme and a generalization of PLEBs to achieve linear space decomposition for nearest neighbor searching. © Springer-Verlag Berlin Heidelberg 2002.