Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Low-complexity and flexible spectrum sensing is one of the challenging tasks in a cognitive radio (CR). Most of the work on energy-detection-based spectrum sensing presented in the literature employ a filter bank (FB) to split the wideband input signal into several subbands and detect the spectrum by computing the energy of subbands. However, for a mobile CR handset, a filter-bank-based spectrum sensing is not an area- and power-efficient scheme. In this paper, a novel spectrum-sensing scheme based on a reconfigurable digital downconverter (RDDC) and a reconfigurable filter based on coefficient decimation is proposed for mobile CR handsets, which has very low complexity and high flexibility compared to conventional FB approaches. The basic idea is to rotate the spectrum using an RDDC and filter the desired portion of the spectrum using the reconfigurable filter, which then results in very low complexity. The implementation results on Virtex-4 field-programmable gate array show that our method offers significant reductions in gate count, power consumption, and delay over conventional discrete Fourier transform FB-based spectrum sensing. © 2011 IEEE.

Department of Electrical Engineering

IEEE Transactions on Circuits and Systems II: Express Briefs

A low-complexity flexible spectrum-sensing scheme for mobile cognitive radio terminals

A new approach to implement computationally efficient reconfigurable filter banks (FBs) is presented. If the coefficients of a finite impulse response filter are decimated by M, that is, if every Mth coefficient of the filter is kept unchanged and remaining coefficients are replaced by zeros, a multi-band frequency response will be obtained. The frequency response of the decimated filter will have bands with centre frequencies at 2πk/M, where k is an integer ranging from 0 to M-1. If these multi-band frequency responses are subtracted from each other or selectively masked using inherently low complex wide transition-band masking filters, different low-pass, high-pass, band-pass and band-stop frequency bands are obtained. The resulting FB, whose bands' centre frequencies are located at integer multiples of 2π/M, is a low complexity alternative to the well-known uniform discrete Fourier transform FBs (DFTFBs). It is shown that the channeliser based on the proposed FB does not require any DFT for its implementation unlike a DFTFB. It is also shown that the proposed FB is more flexible and easily reconfigurable than the DFTFB. Furthermore, the proposed FB is able to receive channels of multiple standards simultaneously, whereas separate FBs would be required for simultaneous reception of multi-standard channels in a DFTFB-based receiver. This is achieved through a second stage of coefficient decimation. Implementation result shows that the proposed FB offers an area reduction of 41% and improvement in the speed of 50.8% over DFTFBs. © 2011 The Institution of Engineering and Technology.

IET Circuits, Devices and Systems

Low complexity flexible filter banks for uniform and non-uniform channelisation in software radios using coefficient decimation

The ability to support multiple channels of different communication standards, in the available bandwidth, is of importance in modern software defined radio (SDR) receivers. An SDR receiver typically employs a channelizer to extract multiple narrowband channels from the received wideband signal using digital filter banks. Since the filter bank channelizer is placed immediately after the analog-to-digital converter (ADC), it must operate at the highest sampling rate in the digital front-end of the receiver. Therefore, computationally efficient low complexity architectures are required for the implementation of the channelizer. The compatibility of the filter bank with different communication standards requires dynamic reconfigurability. The design and realization of dynamically reconfigurable, low complexity filter banks for SDR receivers is a challenging task. This paper reviews some of the existing digital filter bank designs and investigates the potential of these filter banks for channelization in multi-standard SDR receivers. We also review two low complexity, reconfigurable filter bank architectures for SDR channelizers based respectively on the frequency response masking technique and a novel coefficient decimation technique, proposed by us recently. These filter bank architectures outperform existing ones in terms of both dynamic reconfigurability and complexity. © 2008 Springer Science+Business Media, LLC.

World University root node

Journal of Signal Processing Systems

Filter bank channelizers for multi-standard software defined radio receivers

We consider the existence of multiple positive solutions to the steady state reaction diffusion equation with Dirichlet boundary conditions of the form:. Here δu=div(∇u) is the Laplacian of u, 1λ is the diffusion coefficient, K and c are positive constants and Ω⊂RN is a smooth bounded region with ∂. Ω in C2. This model describes the steady states of a logistic growth model with grazing in a spatially homogeneous ecosystem. It also describes the dynamics of the fish population with natural predation. In this paper we discuss the existence of multiple positive solutions leading to the occurrence of an S-shaped bifurcation curve. We prove our results by the method of sub-supersolutions. © 2011 Elsevier Inc.

Department of Mathematics

Journal of Mathematical Analysis and Applications

S-shaped bifurcation curves in ecosystems

Department of Mechanical Engineering

International Journal of Engineering Science and Technology

Studies on the effect of vibration on hot cracking and grain size in AA 7075 aluminum alloy welding

The nickel based Colmonoy 5 alloy powder was deposited on 316 L (N) austenitic stainless steel substrate. In order to examine the effects of aging treatment on the wear behavior of a nickel based hardfacing alloy, the as-deposited coating was aged at 580°C for 5000h in ambient atmosphere. Coating microstructures were characterised by scanning and transmission electron microscopy. Sliding tests were conducted under self mated condition at room temperature and 550°C using a pin-on disc type apparatus. The wear loss of the aged coating was found to be higher than that of the as deposited coating. The coarse grained structure with carbide (Cr23C6) precipitation in the aged coating would account for the higher sliding wear loss. However, the aged coating, with reduced hardness exhibits similar wear behavior of as deposited coating during sliding at 550°C. © (2011) Trans Tech Publications.

Advanced Materials Research

Effect of aging treatment on microstructure and wear behaviour of a nickel based hardfaced coating

In this paper we study the suitability of the Metropolis Algorithm and its generalization for solving the shortest lattice vector problem (SVP). SVP has numerous applications spanning from robotics to computational number theory, viz., polynomial factorization. At the same time, SVP is a notoriously hard problem. Not only it is NP-hard, there is not even any polynomial approximation known for the problem that runs in polynomial time. What one normally uses is the LLL algorithm which, although a polynomial time algorithm, may give solutions which are an exponential factor away from the optimum. In this paper, we have defined an appropriate search space for the problem which we use for implementation of the Metropolis algorithm. We have defined a suitable neighbourhood structure which makes the diameter of the space polynomially bounded, and we ensure that each search point has only polynomially many neighbours. We can use this search space formulation for some other classes of evolutionary algorithms, e.g., for genetic and go-with-the-winner algorithms. We have implemented the Metropolis algorithm and Hasting's generalization of Metropolis algorithm for the SVP. Our results are quite encouraging in all instances when compared with LLL algorithm. © 2011 IEEE.

Department of Computer Science and Engineering

Proceedings of the 2011 11th International Conference on Hybrid Intelligent Systems, HIS 2011

Metropolis algorithm for solving Shortest lattice Vector Problem (SVP)

Model based methods for fault identification in rotating systems are gaining importance for the last three decades due to their ability to identify both location and severity of the fault. Model based methods are of different types. Among them, equivalent loads minimization method is one method. In this method, fault is identified in a rotor bearing system by minimizing difference between equivalent loads estimated in the system due to the fault and theoretical fault model loads. This method has a limitation that the error in identified fault parameters increases with decrease in number of measured vibrations. Thus a comprehensive methodology for fault identification with minimum error even in case of fewer measured vibrations is attempted in the present work. Two different approaches: equivalent loads minimization and vibration minimization method are applied for the identification of unbalance fault in a rotor system. Unbalance fault is identified using proposed methods by measuring transverse vibrations at only one location. © 2010 Elsevier Ltd All rights reserved.

Journal of Sound and Vibration

Identification of unbalance in a rotor bearing system

We demonstrate injection, transport, and detection of spins in spin valve arrays patterned in both copper based chemical vapor deposition (Cu-CVD) synthesized wafer scale single layer and bilayer graphene. We observe spin relaxation times comparable to those reported for exfoliated graphene samples demonstrating that chemical vapor deposition specific structural differences such as nanoripples do not limit spin transport in the present samples. Our observations make Cu-CVD graphene a promising material of choice for large scale spintronic applications. © 2011 American Chemical Society.

Department of Physics

Fulltext

Nano Letters

Toward wafer scale fabrication of graphene based spin valve devices

Kuttanad region is the largest agricultural area in the state of Kerala, India. The soil in this region is dark brown colored highly compressible clay with high organic content. Few studies are reported in this clay even though a significant number of substructure and embankment failures have occurred in the past. This paper presents the details and results of an experimental investigation conducted to study the influence of organic content on the physical and engineering properties of the Kuttanad clay. The test results showed that the organic content has considerable adverse effect on the geotechnical properties of this clay. Plasticity and compressibility characteristics were increased with increase in organic content. The shear strength of the clay was greatly decreased with increase in organic content. However negligible variation in maximum dry density was observed with increase in organic content. © 2011, ejge.