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2006 Annual India Conference, INDICON

作者： Sengar, Sujata Joshi, S.D. Prasad, S. Division of ECE Netaji Subhas Institute of Technology New Delhi-110075 India Department of Electrical Engineering IIT Delhi Hauz Khas New Delhi-110016 India

ISBN: (纸本)1424403707

Multi wavelet multiplexing is a signal transmission technique in which the message symbols are coded onto the multiplicity 'R' wavelet basis functions for transmission. The proposed transmission scheme comes under the class of orthogonally multiplexed communication. The use of multiplicity 'R' wavelet basis functions enhances the data transmission rate. On the other hand, the property of orthogonality enables the design of a simple correlation receiver. The use of 'L'scale multiplicity 'R' multi wavelet multiplexing along with matched filtering at the receiver effectively converts a frequency selective fading channel into 'RL' flat fading channels. We have examined the performance of this multiplexing scheme from a Rate-Diversity trade-off point of view. Further, a simple channel estimation technique for lower data rates has been proposed. © 2006 IEEE.

关键词： Frequency selective fading

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Characterization of Discrete-time Fractional Brownian motion

Characterization of Discrete-time Fractional Brownian motion

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IEEE India Conference (INDICON)

作者： Anubha Gupta ShivDutt Joshi Division of Computer Engineering Netaji Subhas Institute of Technology New Delhi India Electrical Engineering Department Indian Institute of Technology New Delhi India

In this paper, we present the characterization of the discrete-time fractional Brownian motion (dfBm). Since, these processes are non-stationary; the auto-covariance matrix is a function of time. It is observed that the eigenvalues of the auto-covariance matrix of a dfBm are dependent on the Hurst exponent characterizing this process. Only one eigenvalue of this auto-covariance matrix depends on time index n and it increases as the time index of the auto-covariance matrix increases. All other eigenvalues are observed to be invariant with time index n in an asymptotic sense. The eigenvectors associated with these eigenvalues also have a fixed structure and represent different frequency channels. The eigenvector associated with the time-varying eigenvalue is a low pass filter

关键词： Brownian motion Eigenvalues and eigenfunctions Random processes Frequency Fractals Gaussian noise Image texture analysis Signal processing Filters Adaptive signal processing

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A Novel Least Mean Squares Algorithm for tracking a Discrete-time fBm Process

A Novel Least Mean Squares Algorithm for tracking a Discrete...

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IEEE India Conference (INDICON)

This paper presents a novel variable step-size LMS (VSLMS) algorithm for tracking a discrete-time fractional Brownian motion that is inherently non-stationary. In the proposed work, one of the step-size values requires time-varying constraints for the algorithm to converge to the optimal weights whereas the constraints on the remaining step-size values are time-invariant in the decoupled weight vector space. It computes the step-size matrix by estimating the Hurst exponent required to characterize the statistical properties of the signal at the input of the adaptive filter. The experimental set-up of an adaptive channel equalizer is considered for equalization of these signals transmitted over stationary AWGN channel. The performance of the proposed variable step-size LMS algorithm is compared with the unsigned VSLMS algorithm and is observed to be better for the class of non-stationary signals considered

关键词： Least mean square algorithms Signal processing algorithms Least squares approximation Brownian motion Random processes Tracking Adaptive filters Adaptive equalizers AWGN channels Adaptive signal processing

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Directed Convergence Heuristic: A fast & novel approach to Steiner Tree Construction

Directed Convergence Heuristic: A fast & novel approach to S...

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IFIP International Conference on Very Large Scale Integration (VLSI-SoC)

作者： Shampa Chakraverty Arvind Batra Aman Rathi Department of Computer Engineering Netaji Subhas Institute of Technology University of Delhi New Delhi India

One of the fundamental problems encountered during the VLSI design flow is to find minimum length nets that connect specific nodes on the chip. The challenge lies in finding an efficient solution to the Steiner tree problem in graphs (SPG) that not only maximizes the routing efficiency but also lends itself well for fast implementation. In this paper, we propose a new and innovative approach for solving the Steiner tree problem, called the "directed convergence heuristic (DCH)". In essence, the DCH based algorithm places entities called pawns on nodes that need to be connected. These pawns move towards each other in a directed fashion and while doing so, leave trails for constructing a Steiner tree between the nodes. When all the pawns converge at a node, the trails merge to create a Steiner tree. Experimental results on benchmark Steiner trees show that DCH is robust and converges faster while yielding competitive near optimal solutions. The algorithm is amenable for implementation on parallel computing architectures

关键词： Convergence Routing Very large scale integration Algorithm design and analysis Machine learning algorithms Polynomials Robustness Parallel processing computer architecture Steiner trees

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A systematic approach for engineering inter model transformations

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International Journal of Information and Management Sciences 2006年第4期17卷 15-34页

作者： Prakash, Naveen Srivastava, Sangeeta Sabharwal, Sangeeta Jaypee University of Information Technology India Delhi University India Netaji Subhas Institute of Technology India Jaypee University of Information Technology Waknaghat Simla H.P. India Department of Computer Science BCAS Delhi University Dwarka New Delhi India Division of Computer Engineering Netaji Subhas Institute of Technology Dwarka New Delhi 110045 India

Rather than produce schema transformation methods for every different pair of model, we formulate a systematic, computer supported generic technique of performing transformation across models. We formalize the transformation technique by using the graph theoretic notion of isomorphism. Model concepts are organized in an is built of method graph. The generation technique is used to establish isomorphism between the concepts of the two graphs by generating nodes and edges. This technique produces feasible mappings, which can be presented to the method engineer for subsequent fine-tuning. The technique is illustrated for mapping between ER and Relational models. It is a soft approach as it allows the method engineer to accept or make modifications as per his requirement.

关键词： Systems engineering

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Power Aware Clustering Technique in Wireless Ad Hoc Networks

Power Aware Clustering Technique in Wireless Ad Hoc Networks

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International Symposium on Ad Hoc and Ubiquitous Computing (ISAUHC)

作者： Sanjay Kumar Dhurandher G. V. Singh Division of Computer Engineering Netaji Subhas Institute of Technology University of Delhi New Delhi India School of Computer & Systems Sciences Jawaharlal Nehru University New Delhi India

The concept of clustering has been proved to be very effective in managing the resources at the MAC level in a wireless multi hop network. In this paper we present a power aware clustering algorithm for mobile ad-hoc networks. The proposed algorithm takes into account, the transmission power, transmission rate, mobility, battery power, and the degree of a node for cluster head selection. The Lowest-ID algorithm finds the local minima of IDs and the Weighted Clustering Algorithm (WCA) finds the global minima of weights for selecting cluster heads. In contrast, the proposed power aware clustering algorithm finds only the local minima of weights for the clustering process. Through simulations, we investigated the performance of our algorithm with that of Lowest-ID and WCA in terms of the number of clusterhead changes, the number of reaffiliations, the control overhead and the throughput. The results have demonstrated the superior performance of the proposed algorithm in terms of energy consumption in the network.

关键词： Mobile ad hoc networks Clustering algorithms Energy consumption Network topology Routing computer networks Power engineering computing Energy management Resource management Ad hoc networks

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Observer Based Position and Speed Estimation of Interior Permanent Magnet Motor

Observer Based Position and Speed Estimation of Interior Per...

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International Conference on Power Electronic Drives and Energy Systems for Industrial Growth

作者： Bhim Singh Prerna Gaur A.P. Mittal Electrical Engineering department Indian Institute of Technology New Delhi India Instrumentation and control engineering Division Netaji Subhas Institute of Technology New Delhi India

This paper presents position sensorless interior permanent magnet synchronous motor drive using a discretized extended kalman filter algorithm (EKF). An observer based speed estimator which can be used for the state estimation of a non linear dynamic system in real time is presented here. Speed and position estimation of IPM is simulated using MATLAB and results of step variation in speed, load perturbation and flux weakening are presented to substantiate the proposed estimation of the speed.

关键词： Permanent magnet motors Rotors State estimation Magnetic sensors Mathematical model Sensorless control AC motors DC motors Torque Observers

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Game-theoretic-reinforcement-adaptive neural controller for nonlinear systems

Game-theoretic-reinforcement-adaptive neural controller for ...

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American Control Conference (ACC)

作者： S. Rajneesh G. Madan Faculty in ICE Division Netaji Subhas Institute of Technology New Delhi India Electrical Engineering Department Indian Institute of Technology New Delhi India

This paper is concerned with application of a game-theoretic formulation for direct adaptive optimal control of nonlinear systems affected by bounded noise/disturbances. Almost all of the reinforcement learning (RL) approaches employ a Markov decision process (MDP) setting, which is inadequate for handling noise/disturbances as it disallows an explicit representation of noise/disturbances. The work in this paper addresses this problem by showing how a game theoretic RL formulation can effectively cope with disturbances with no preliminary offline learning. The work demonstrates the application of neural networks (NN) in a Markov game setup. We provide empirical results of applying the approach on an inverted pendulum swing-up task and compare its performance against Q learning. The results bring out the superiority of the Markov game formulation for direct adaptive optimal control over the MDP setting. Further, the results demonstrate that NN could be used as an effective tool for speeding up learning in large Markov games and for extending the game theoretic direct adaptive optimal control to a continuous state space

关键词： Nonlinear control systems Control systems Nonlinear systems Programmable control Adaptive control Optimal control Game theory Neural networks Learning State-space methods

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An Application of Multi Wavelets in Wireless Communication In The Presence Of Frequency Selective Fading

An Application of Multi Wavelets in Wireless Communication I...

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IEEE India Conference (INDICON)

作者： Sujata Sengar S. D. Joshi S. Prasad Division of ECE Netaji Subhas Institute of Technology New Delhi India Department of Electrical Engineering IIT Delhi New Delhi India

Multi wavelet multiplexing is a signal transmission technique in which the message symbols are coded onto the multiplicity `R' wavelet basis functions for transmission. The proposed transmission scheme comes under the class of orthogonally multiplexed communication. The use of multiplicity `R' wavelet basis functions enhances the data transmission rate. On the other hand, the property of orthogonality enables the design of a simple correlation receiver. The use of `L' scale multiplicity `R' multi-wavelet multiplexing along with matched filtering at the receiver effectively converts a frequency selective fading channel into `RL' flat fading channels. We have examined the performance of this multiplexing scheme from a rate-diversity trade-off point of view. Further, a simple channel estimation technique for lower data rates has been proposed

关键词： Wireless communication Frequency Fading Matched filters Diversity reception Multiresolution analysis Filtering Channel estimation OFDM Data communication

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Offline Adaptive Forward Error Correction (AFEC) for Reliable Multicast

Offline Adaptive Forward Error Correction (AFEC) for Reliabl...

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IEEE International Conference on Networking, Sensing and Control

作者： R. Malik A. Munjal S. Chakraverty Kasenna Inc. Mountain View CA USA Computer Science and Engineering Department Netaji Subhas Institute of Technology University of Delhi Dwarka India

The use of FEC/AFEC (adaptive forward error correction) for reliable multicast is not new. However, they are still not widely accepted as the de facto standard for recovering lost data. The primary reason is the added CPU overhead involved in generating the parity data. In this paper, we propose a technique to move the generation of AFEC parity data offline, on the server side. Thus, avoiding any CPU overhead associated with parity data generation. The challenge on the server side would be to meet the expectations of all the clients for a particular multicast. Since different clients may experience different loss rates at the same time, the challenge is to satisfy their needs in an optimal way without causing network congestion

关键词： Forward error correction Multicast protocols Redundancy Encoding Automatic repeat request computer science Network servers Wireless networks Roads Data engineering

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