Thiruvananthapuram, India

College of Engineering, Trivandrum
Thiruvananthapuram, India

The College of Engineering, TVM, commonly known as CET, is situated in Thiruvananthapuram, the capital city of Kerala, founded in 1939 during the reign of the Travancore King, Sree Chithira Thirunal Balarama Varma. The college was ranked 18th overall among 100 Top Engineering colleges of the country by Dataquest-CMR Top T-Schools Survey 2011. Wikipedia.

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Vidyadharan D.S.,College of Engineering, Trivandrum | Thampi S.M.,Indian Institute of Information Technology and Management Gwalior
Journal of Intelligent and Fuzzy Systems | Year: 2017

Detecting forged digital image has been an active research area in recent times. Tampering introduces artifacts within images that differentiate tampered images from authentic images. Forgery detection techniques try to identify these artifacts by analyzing differences in the texture properties of the image. In this paper, we propose a multi-texture description based method to detect tampering. Different texture descriptors considered are Local Binary Pattern, Local Phase Quantization, Binary Statistical Image Features and Binary Gabor Pattern. The method captures subtle texture variations at different scales and orientation using Steerable Pyramid Transform (SPT) decomposition of image. The different texture descriptors extracted from each subband image after SPT decomposition is combined to form the multi-texture representation. Then, ReliefF feature selection method is applied on this high dimensional multi-texture representation to generate a compact representation. This compact multi-texture representation is classified using Random Forest classifier. We have evaluated the performance of individual texture descriptors and multiple textures in detecting image forgery. Experimental results show that the compact multi-texture description has improved detection accuracy. © 2017-IOS Press and the authors. All rights reserved.

Soumya T.,College of Engineering, Trivandrum | Thampi S.M.,Indian Institute of Information Technology and Management Gwalior
Journal of Intelligent and Fuzzy Systems | Year: 2017

The night video fusion algorithms integrate the visuals captured by a security surveillance camera, which in turn improve the visual perception. The recent development in night fusion research focused on fusing both illuminated and non-illuminated areas simultaneously however, the natural color of the light area may be lost. Moreover, the contrast of the illuminated regions decreases because of the dark pixels surrounding those regions. Hence, the color and contrast should be improved to obtain the actual color of the illuminated regions. We propose a fuzzy inference system based wavelet fusion to enhance the light regions of a nonuniform illuminated night video surveillance system. To include spatial and temporal variations of the illuminated regions, a spatio-temporal illumination approach is used. A contribution index of the illuminated regions is generated using a fuzzy membership function. Subsequently, the stationary wavelets are used to decompose high-frequency and low-frequency coefficients of both night and day background frames for frame fusion. The contribution index selects the illuminated regions presented in these wavelet coefficients for fusion. Finally, the inverse wavelet transform is applied to reconstruct the illumination enhanced frame. The proposed approach effectively highlights the illuminated regions and provides a better visual perception. © 2017-IOS Press and the authors. All rights reserved.

Reddy M.L.P.,Indian National Institute for Interdisciplinary Science and Technology | Divya V.,Indian National Institute for Interdisciplinary Science and Technology | Pavithran R.,College of Engineering, Trivandrum
Dalton Transactions | Year: 2013

Visible-light sensitized luminescent europium(iii) molecular materials are of considerable importance because their outstanding photophysical properties make them well suited as labels in fluorescence-based bioassays and low-voltage driven pure red-emitters in optoelectronic technology. One challenge in this field is development of visible-light sensitizing ligands that can form highly emissive europium(iii) complexes with sufficient stability and aqueous solubility for practical applications. Indeed, some of the recent reports have demonstrated that the excitation-window can be shifted to longer-wavelengths in europium(iii)-β-diketonate complexes by appropriate molecular engineering and suitably expanded π-conjugation in the complex molecules. In this review, attention is focused on the latest innovations in the syntheses and photophysical properties of visible-light sensitized europium(iii)-β- diketonate complexes and their application as bioprobes for cellular imaging. Furthermore, luminescent nanomaterials derived from long-wavelength sensitized europium(iii)-β-diketonate complexes and their application in life sciences are also highlighted. © 2013 The Royal Society of Chemistry.

Rajeev T.,College of Engineering, Trivandrum | Ashok S.,National Institute of Technology Calicut
Applied Energy | Year: 2015

Demand-side management programs such as load shifting utilise the flexibility in the load consumption pattern of consumers to enable the effective capacity utilisation of renewable energy sources. The locational and temporal characteristics of renewable energy sources cause forecasting and operational challenges in the implementation of such a renewable energy program. In this paper, a dynamic load-shifting program using real-time data in a cloud computing framework is proposed to address the aforementioned issues. A new dynamic renewable factor is proposed to facilitate on-time incentive based load shifting program. The effectiveness of the dynamic load-shifting program was evaluated using simulated case studies. The case study indicates that PV energy utilisation at the consumer side is increased by 18% by the application of the proposed load-shifting program. The study result in Kerala, India, consisting of more than 7.5 million domestic consumers, indicates that demand reduction of 250-300. MW at times of peak demand can be achieved by using load shifting in the domestic sector. © 2015 Elsevier Ltd.

Pinto B.,College of Engineering, Trivandrum | Anurenjan P.R.,College of Engineering, Trivandrum
ICCSP 2011 - 2011 International Conference on Communications and Signal Processing | Year: 2011

Video stabilization is one of the most important enhancement techniques used to remove undesired motion in a video. Combination of global camera motion estimation along with motion separation determines the undesired motion, which is to be compensated to produce a stable video sequence. In this paper a novel method for robust video stabilization is proposed which uses Speeded Up Robust Features(SURF) as stable feature points to be tracked between frames for global motion estimation. Different measures are taken to select the most appropriate feature point trajectories. A discrete kalman filter is used to smoothen so estimated motion vectors and the resultant stabilized video is obtained by compensating the unstable motion. © 2011 IEEE.

Swarnalatha K.,College of Engineering, Trivandrum
Journal of environmental management | Year: 2013

Urbanisation has a profound influence on our environment, and its burden is often transferred to aquatic systems. The surface sediments of urban lake systems are severely threatened with major contamination on a daily basis. Empirical evidence gleaned from the study of Akkulam Veli, a tropical urban lake in Southern India, indicates the need to evaluate all factors defining the contamination status of lake systems, rather than the conventional procedure that use Al or Fe, and select normalisers to evaluate metal enrichment in contaminated lake systems. A two step correlation analysis was done using Fe, Al, Co, Mn, Ti and Si as normalisers for Cr, Co, Ni, Cu, Zn and Pb. However, Fe, Al, Co, Mn and Ti are found to be unsuitable as normalisers for various reasons, including the redox condition of the lake for Fe, the geological structure of the lake, with its laterite basin that is conducive to high concentrations of Al, the near-detectable range in many stations that can magnify the enrichment for Co, the escalation in EF values for Mn, and the probability of effluent entry from the nearby titanium-based industry for Ti. Si, which is highly refractory, stable, associated with clay minerals, and unaffected by environmental factors such as reduction/oxidation, adsorption/desorption and other diagenic processes, appears to be the most appropriate normaliser in AV lake sediments. The average EF values calculated using Si as a normaliser are Pb (3.88) > Cr (1.77) > Zn (1.71) > Co (1.34) > Cu (1.29) > Ni (0.94). The results of the study show that this alternate method is more accurate at estimating EF values, which in turn can be employed more precisely to evaluate the extent of anthropogenic contamination in urban lake systems with highly contaminated surface sediments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Jacob B.,College of Engineering, Trivandrum | Baiju M.R.,College of Engineering, Trivandrum
IET Power Electronics | Year: 2012

In this study, sigma-delta (ΣΔ) modulation-based random pulse width modulations (PWM) scheme with vector quantisation for three-level inverter is proposed. In the proposed scheme, the instantaneous reference space vector is mapped to an equivalent two-level inverter and the proposed space-vector-based ΣΔ modulation is applied on this mapped reference space vector. The scheme uses the principle of vector quantisation for quantising the mapped reference space vector in the ΣΔ modulator. The switching signals are generated directly from the amplitude of the three-phase reference signal without using lookup table and complex arithmetic calculations. The resultant vectors of the two-level inverter can be easily translated to the actual switching vectors, and this proposed method of working on the mapped reference space vector makes the proposed scheme suitable for any general n-level inverter. The switching vectors of the inverter are naturally selected ensuring optimum switching sequence under all conditions including the over-modulation region. The proposed scheme is implemented for three-level inverter driving a two-horse power (HP) three-phase induction motor. The performance of the proposed scheme is compared with space-vector PWM scheme and random PWM schemes with different modulation indices and experimental results are presented. © 2012 The Institution of Engineering and Technology.

Jacob B.,College of Engineering, Trivandrum | Baiju M.R.,College of Engineering, Trivandrum
IET Electric Power Applications | Year: 2011

A Space Vector based Pulse Density Modulation scheme for a two level Voltage Source Inverter is proposed in this paper. The proposed scheme employs a first order Sigma Delta Modulator. The principle of Vector Quantization is used for quantizing the reference voltage Space Vector in the Sigma Delta Modulator. For the spatial quantization, the inverter voltage vector space is divided into seven Voronoi regions. In this paper, a method is proposed to code these Voronoi regions using instantaneous reference phase amplitudes without using lookup table. The proposed scheme naturally selects the switching vectors in the over-modulation condition and hence results in a smooth transition from linear to over-modulation region. In Pulse Density Modulation scheme, the switching frequency varies randomly, resulting in the spreading of harmonic spectra. The minimum pulse width that can occur in the proposed scheme is equal to the sampling time period. Therefore, the occurrence of pulse width less than the trun on time of the switching devices is avoided. The proposed scheme is implemented for a 11.5 kVA two level inverter driving 2-HP three phase induction motor. Experimental results of proposed scheme are compared with s Space Vector PWM scheme and Random Space Vector PWM scheme. © 2011 The Institution of Engineering and Technology.

Jacob B.,College of Engineering, Trivandrum | Baiju M.R.,College of Engineering, Trivandrum
IEEE Transactions on Industrial Electronics | Year: 2013

A generalized space-vector-based spread spectrum modulation scheme for multilevel inverters is proposed in this paper. The proposed scheme uses the principle of sigma-delta modulation as applied to analog-to-digital converters (ADCs), based on the view that a multilevel converter could be interpreted as an oversampling ADC. The principle of vector quantization is utilized for quantizing the instantaneous reference voltage space vector in the proposed space-vector-based sigma-delta converter. The switching vectors of the inverter are naturally selected without sector identification, ensuring optimum switching sequence under all conditions including the overmodulation region. As the sigma-delta converter results in a randomly varying switching frequency, the proposed scheme has spread spectrum characteristics. To avoid fractional arithmetic, a 60 $\circ coordinate system is used to represent the space vector in this paper. The proposed scheme can be used for any general $n$-level inverter, and experimental results are presented for four-, five-, and six-level inverters, driving a 2-hp three-phase induction motor in an open-end winding configuration. The experimental results of the proposed scheme are compared with the space-vector pulsewidth modulation (PWM) scheme and random PWM scheme. © 1982-2012 IEEE.

Arun K.G.,Chennai Mathematical Institute | Pai A.,College of Engineering, Trivandrum
International Journal of Modern Physics D | Year: 2013

Gravitational wave (GW) observations of coalescing compact binaries will be unique probes of strong-field, dynamical aspects of relativistic gravity. We present a short review of various schemes proposed in the literature to test general relativity (GR) and alternative theories of gravity using inspiral waveforms. Broadly these schemes may be classified into two types: model dependent and model independent. In the model dependent category, GW observations are compared against a specific waveform model representative of a particular theory or a class of theories such as scalar-tensor theories, dynamical Chern-Simons theory and massive graviton theories. Model independent tests are attempts to write down a parametrized gravitational waveform where the free parameters take different values for different theories and (at least some of) which can be constrained by GW observations. We revisit some of the proposed bounds in the case of downscaled LISA configuration (eLISA) and compare them with the original LISA configuration. We also compare the expected bounds on alternative theories of gravity from ground-based and space-based detectors and find that space-based GW detectors can test GR and other theories of gravity with unprecedented accuracies. We then focus on a recent proposal to use singular value decomposition of the Fisher information matrix to improve the accuracies with which post-Newtonian theory can be tested. We extend those results to the case of space-based detector eLISA and discuss its implications. © 2013 World Scientific Publishing Company.

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