Model Engineering College
Recent publications
This paper presents the study of the impact of gate work function engineering on the performance of AlGaN channel high electron mobility transistor. The proposed devices with dual material and triple material gate structures result in improved electrical characteristics. The devices exhibit a peak transconductance of 11.86 mS, 11.80 mS respectively for triple and dual material gate structures. A comparative analysis on the performance of the proposed device structures with conventional AlGaN channel HEMT is presented. The devices are able to offer superior RF performance compared to the conventional device with fT values of 0.89 GHz, 0.889 GHz for triple material and dual material gate devices respectively. By incorporating gate field plates, field crowding at the gate edge can be reduced further. The field plated structure can cater to better high voltage operation with a slight penalty on the high frequency performance.
Deep neural network algorithms have shown promising results for music source signal separation. Most existing methods rely on deep networks, where billions of parameters need to be trained. In this paper, we propose a novel autoencoder framework with a reduced number of parameters to separate the drum signal component from a music signal mixture. A denoising autoencoder with a U-Net architecture and direct skip connections was employed. A dense block is included in the bottleneck of the autoencoder stage. This technique was tested on both demixing secret data (DSD) and the MUSDB database. The source-to-distortion ratio (SDR) for the proposed method was at par with that of other state-of-the-art methods, whereas the number of parameters required was quite low, making it computationally more efficient. The experiment performed using the proposed method to separate drum signal yielded an average SDR of 5.71 on DSD and 6.45 on MUSDB database while using only 0.32 million parameters.
In this paper, a dopingless DRAM based on work function engineered Tunnel field effect transistor is proposed. Gate metal workfunction engineering is done to enhance ON/OFF current ratio of drain current, thereby improving the sense margin and retention time. Drain electrode is made up of dual metal, so as to suppress ambipolar current. The analysis of dual material gate dual drain electrode DRAM (DMG DDE DRAM) and triple material gate dual drain electrode DRAM (TMG DDE DRAM) is done in terms of retention time and sense margin. The performance parameters with different device dimensions and bias conditions are analyzed. It is observed that the proposed DRAMs work well even when the dimensions are scaled down. In addition, the proposed DRAMs have comparable performance with the conventional DRAMs and provide better performance when compared with other dopingless DRAM. Retention times of 430 ms and 370 ms, sense margins of 130 nA and 101 nA are achieved with TMG DDE DRAM and DMG DDE DRAM respectively.
Tunnel Field Effect Transistor can be introduced as an emerging alternate to MOSFET which is energy efficient and can be used in low power applications. Due to the challenge involved in integration of band to band tunneling generation rate, the existing drain current models are inaccurate. A compact analytical model for simple tunnel FET and pnpn tunnel FET is proposed which is highly accurate. The numerical integration of tunneling generation rate in the tunneling region is performed using Simpson’s rule. Integration is done using both Simpson’s 1/3 rule and 3/8 rule and the models are validated against numerical device simulations. The models are compared with existing models and it is observed that the proposed models show excellent agreement with device simulations in the entire region of operation with Simpson’s 3/8 rule exhibiting the maximum accuracy.
Tunnel Field Effect Transistor can be introduced as an emerging alternate to MOSFET which is energy efficient and can be used in low power applications. Due to the challenge involved in integration of band to band tunneling generation rate, the existing drain current models are inaccurate. A compact analytical model for simple tunnel FET and pnpn tunnel FET is proposed which is highly accurate. The numerical integration of tunneling generation rate in the tunneling region is performed using Simpson’s rule. Integration is done using both Simpson’s 1/3 rule and 3/8 rule and the models are validated against numerical device simulations. The models are compared with existing models and it is observed that the proposed models show excellent agreement with device simulations in the entire region of operation with Simpson’s 3/8 rule exhibiting the maximum accuracy.
Image De-blurring and super-resolution (SR) are computer vision tasks aiming to restore image detail and spatial scale, respectively. Despite the significant improvement in image quality resulting from improvement in optical sensors and general electronics, camera shake blur significantly undermines the quality of hand-held photographs. We evaluated the state-of-the-art super-resolution convolution neural network(SR-CNN) architecture and proposed a new architecture for SR application inspired by SR-CNN combined with De-blurring. This paper focus super resolution of a de-focussed and motion blurred natural images. Unlike most de-blurring methods that attempt to solve an inverse problem through a variational formulation, deblurring method applied in this work directly estimates the blur kernel by modeling statistical irregularities in the power spectrum of blurred natural images. Extensive experiments indicate that the proposed method not only generates remarkably clear HR images, but also achieves compelling results in PSNR, MSE and SSIM quantitatively.
This paper deals with the existence of a compact stellar object, precisely strange (quark) star, in the framework of Einstein’s General Theory of Relativity with Tolman V metric potential, which is one of the simplest forms of potential among his proposals. The potential is given by eν=Kr2n, where K is the constant and n is a parameter [R.C. Tolman, Phys. Rev. 55, 364 (1939)]. Considering charged, static, spherically symmetric, isotropic fluid sphere we have studied different physical features of some strange star candidates namely EXO1785-248,LMCX-4,SMCX-1,SAXJ1808.4-3658,4U1538-52 and HerX-1. To represent the strange quark matter (SQM) distribution we have employed the simplest form of MIT Bag equation of state (EOS), which provides a linear relationship between pressure and density of the matter through Bag constant B. Several tests are done for the stability criteria and physical acceptability of the proposed model. The results show consistency with energy condition, TOV equation, adiabatic index, etc. We have also calculated different physical parameters of our model for the three different consecutive values of Bag constant B which are 83MeV/fm3,90MeV/fm3 and 100MeV/fm3. Among them with B=90MeV/fm3 we have analyzed different properties of the proposed strange star candidates.
There is growing interest in the use of video cameras to conduct aerial surveillance. Compared to conventional framing cameras, videos can monitor ongoing action within a scene, and adjust the camera automatically to track the action. Video documents dynamic events that are not available from aerial photos. This enables the feedback and control of dynamic event-based actions and delivers timely and important knowledge and interpretation that is not accessible elsewhere. Video recordings can be used to map and geo-locate dynamic objects or events in real-time. In this paper, we propose an innovative approach for aerial video surveillance using video content analysis and indexing, to monitor the violation of activities during the emergency lockdown period. Instead of continuously monitoring the video content, this method detects the free movement of persons and vehicles along with the location details from the geotagged videos sent by drone video cameras.
Dendritic nanostructure with the catalytic moiety covalently attached within the core domain and protected from the environment by a polymeric shell was synthesized successfully. This prospective will focus on the exclusive features observed for such a catalytic system with reactive sites present both at the core and the periphery and highlight its potential as enzyme mimics, by synthesizing different bisimidazoles following the MCR method, at room temperature. An unprecedented reaction rate and high yield of products were obtained within a short time, which is supposed to be its ability to form reverse micelle in the core, where the substrates are adequately concentrated. This is the first reported synthesis of bisimidazoles, using the homogeneous PAMAM dendrimer as a basic organocatalyst. The newly synthesized bisimidazoles obtained from bis(3‐aminopropyl)amine were subjected to molecular docking studies against anticancer protein receptor using AutoDock Vina software, to evaluate their activity against breast cancer cell line (3HB5). The research work comprises the synthesis of homogeneous dendritic polyamine with nanosize (figure below), and forms reverse micelle structure in the interior core part of the molecule in solution. The synthesized dendrimers act as a highly efficient organocatalyst for the synthesis of a variety of bisimidazoles. The synthesized bisimidazoles, obtained by using bis(3‐aminopropyl)amine having electron donating functional groups, by molecular docking studies against anticancer protein to evaluate their activity against breast cancer cell line (3HB5) and found that all compounds gave very good docking score.
Numerical simulation for calculation of losses of a new cascaded multilevel inverter (MLI) topology depending upon a bi-directional-blocking-bidirectional–conducting-switch is summarized in this paper. The numerical circuit simulation is performed in PSIM software by utilizing thermal models of power electronic switches. Calculation of conduction and switching losses of a 73 W inverter by relying on data sheet values has also been made. A comparison of efficiency of 73 W inverter using numerical simulation as well as analytical calculation has also been made. The new proposed inverter is a compound of both unidirectional as well as bidirectional power electronic switches challenging the attempt to reduce device count of the cascaded MLI.
This paper reports the synthesis of two new supramolecules, Phenyl (octacyanomethoxy)calix [4]resorcinarene (3a) and 4-Cyanomethoxyphenyl-(octacyanomethoxy)calix [4]resorcinarene (3b) by alkylating the hydroxyl groups present in Phenylcalix [4]resorcinarene and 4-Hydroxyphenylcalix [4]resorcinarene respectively. Full O-alkylation was done at room temperature by simple stirring. The X-ray diffraction studies, were done to get the crystal-packing arrangements of alkylated resorcinarene derivatives. Absorption and emission spectra of the compounds were recorded in different organic solvents and both exhibited negative solvatochromism with the polarity of solvents. Molecular geometry optimization, vibrational wave numbers and frontier molecular orbitals were calculated by dispersion corrected DFT-D method using hybrid density functional ꞷB97X-D and the split-valence double-zeta basis set 6-31G(d). DFT-D studies revealed that the synthesised supramolecules existed in two different conformers, chair (C2h) and Boat (C2V). Boat (C2v) conformer had more stability than the chair (C2h) conformer. HOMO-LUMO energies were calculated to explain the kinetic stability of the compounds, found that Phenyl (octacyanomethoxy)calix [4]resorcinarene has more kinetic stability.
In the current article, we study anisotropic spherically symmetric strange star under the background of f(R, T) gravity using the metric potentials of Tolman–Kuchowicz type (Tolman in Phys Rev 55:364, 1939; Kuchowicz in Acta Phys Pol 33:541, 1968) as \(\lambda (r)=\ln (1+ar^2+br^4)\) and \(\nu (r)=Br^2+2\ln C\) which are free from singularity, satisfy stability criteria and also well-behaved. We calculate the value of constants a, b, B and C using matching conditions and the observed values of the masses and radii of known samples. To describe the strange quark matter (SQM) distribution, here we have used the phenomenological MIT bag model equation of state (EOS) where the density profile (\(\rho \)) is related to the radial pressure (\(p_r\)) as \(p_r(r)=\frac{1}{3}(\rho -4B_g)\). Here quark pressure is responsible for generation of bag constant \(B_g\). Motivation behind this study lies in finding out a non-singular physically acceptable solution having various properties of strange stars. The model shows consistency with various energy conditions, TOV equation, Herrera’s cracking condition and also with Harrison–Zel\('\)dovich–Novikov’s static stability criteria. Numerical values of EOS parameter and the adiabatic index also enhance the acceptability of our model.
The recognition of blood disorder through the visual observation is the most challenging job. In the current technological era computer become the most important part of medical science. The haematological disorders of white blood cells (WBC) are really frequent in medical practices. The objective of this research is to design and development of automated identification of Leukemia using microscopic blood smear image database. This proposed scheme uses the most significant steps of image processing like, pre-processing, image segmentation, extraction of features and classification. The Leukemia smear image database is segmented using Otsu image segmentation. The feature extraction extracts the area, perimeter, solidity, orientation, eccentricity, centroid, entropy and energy features. The classification method applied using neural network, Support vector machine and QDA approach. In the neural network the 60% dataset has been passed for the training, 35% towards the testing and remaining 05% is used for the validation. The SVM and QDA classify the dataset for the two groups such as normal and leukaemia. The classification is done on the extracted 08 features of each image. The performance of the neural network is achieving 98.97% with 1.0246 error rate. The support vector machine is shows the 99.35% accuracy with 0.6500 error rate. The QDA classification reported the 99.70% accuracy with 0.300% error rate. From the reported accuracy the QDA and support vector machine proved as dominant as the neural network.
We report the transient effects in Erbium Doped Fiber Amplifier (EDFA) systems for pulsed signals with different duty-cycles. The work includes the analysis using three different duty-cycles, 10%, 20% and 50%. A curve fitting technique is also proposed to predict the transients of any lesser duty-cycled pulse, once the transients of a larger duty-cycled pulse is known. Mathematical evaluation confirms the double exponential shape of transient distorted signal. Further, EDFA transient effect is experimentally verified on a Wavelength Division Multiplexed (WDM) link by multiplexing high and low bitrate modulated optical signals. We conclude the paper by proposing a transient suppression technique for variable duty-cycle signals and analyzing its effectiveness with different wavelength spacing. Keywords: EDFA, Transients, WDM, Variable duty cycle, Suppression
Necessity has compelled man to improve upon the art of tapping wind energy for power generation: an apt reliever of strain exerted on the non-renewable fossil fuel. Even though wind power is the most accomplished green energy source, reliability and availability are still the primary issues for its successful generation. The components of the wind energy system (WES) have different characteristics which influence the system’s reliability at different levels. Accurate modeling of WES is very essential to study about the possible failure probability which reflects in the availability and economics of operation. This paper aims to present a suitable Markov model for a WES to incorporate the characteristics of condition monitoring (CM). In this work, the accuracy of the developed model is improved by considering failure and repair rates of all the components. A sensitivity analysis is performed using the developed model to learn the characteristics of turbine components that are likely to have an impact on the system’s reliability the most. Results reveal that the components with high failure rates and high mean down times are more critical to reliability. The paper also presents reliability allocation technique as a novel method to improve the availability of WES.
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200 members
Asha r s
  • Research center, CUSAT
Minimol Balakrishnan
  • Department of Biomedical Engineering
Sherly Parackal
  • Department of Applied Sciences
Jagadeesh Kumar
  • Department of Electronics Engineering
Jiby J Puthiyidam
  • Department of Computer Science and Engineering
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Address
Cochin, India
Head of institution
Prof. (Dr. ) V.P Devassia
Phone
+91-484-2577379