Browsing by Author "Singh, M."

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A New Kaiser-Bessel Constant Modulus Technique for Smart Antenna Beamforming
(Springer Science and Business Media Deutschland GmbH, 2022) Shashidhara, K.S.; Dakulagi, V.; Kaur, J.; Yeap, K.H.; Singh, M.; Ratnesh, R.K.
In this work, an improved constant modulus algorithm (CMA) blind beamformer exploiting the Kaiser-Bessel window which is dubbed as â€˜KB-CMAâ€™ for the smart antenna system is presented. In array signal processing, especially in beamforming technology, the CMA is one of the most popular methods due to its low complexity. However, this beamformer has a very slow convergence time and has a large side lobe level (SLL). This hinders the utility of the CMA method in dynamic circumstances where the speedy capture of the user signal is required. Also, this method is not suitable in the wireless applications where conditions of the channel are speedily varying. To circumvent this problem and to make the classical CMA suitable for practical applications, we propose an improved CMA. The major advantage of the new method is that its time of convergence is almost several times quicker than the classical CMA. Furthermore, we exploit the Kaiser-Bessel window to suppress the SLLs of the improved CMA. Experimental results demonstrate that the proposed method has fast convergence time and the reduced SLL. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
A Study on Depth Estimation from Single Image Using Neural Networks
(Institute of Electrical and Electronics Engineers Inc., 2022) Shree, R.; Madagaonkar, S.B.; Singh, M.; Chandra, M.T.A.; Rathnamma, M.V.; Venkataramana, V.; Chandrasekaran, K.
Depth estimation is fundamental in upcoming technology advancements like scene understanding, robot vision, intelligent driver assistance systems, and many new technologies. Estimating the depth of objects from a viewport can be achieved using various mathematical, geometrical, and stereo concepts, but the process is unaffordable and erroneous. Depth estimation from a single can be accurately done using neural networks. Although this is a challenging task, researchers around the globe have published various works. The works include different neural network standards like CNN, GANs, Encoder-Decoder. The paper analyses and examines famous works in this field of study. Later in the paper, a comparative survey of depth estimation approaches using neural networks is done. Â© 2022 IEEE.
Advancement and challenges in MOSFET scaling
(Elsevier Ltd, 2021) Ratnesh, R.K.; Goel, A.; Kaushik, G.; Garg, H.; Chandan, n.; Singh, M.; Prasad, B.
In this study, we enlighten about the field effect transistors (FET) and their technologies. As far as very large integration is concerned, researchers are continuously focusing on scaling the transistors in a way to improve the transistors efficiency. In today's era, electronics and semiconductor industries are developing in such a manner that different nano scaled transistors work with low power as well as low cost designs. However, scaling of metal oxide semiconductor field effect transistor (MOSFET) into nanometer scale induces some effects like short channel effects, tunneling effects, and threshold voltage effects etc., which degrade the performance as well as cause challenges to the fabrication process. This review article deals not only with the limitations of scaling and ways to resolve them but also contains detailed study of silicon nanowire and other distinctive nano FET. Moreover, these research finding are helpful in directing the current advancements in MOSFET technology and gave a brief sketch of possible future technologies. © 2021
Aperture-Coupled Plasmonic Ring Resonator-Based Temperature Sensor: 3-D FEM Modeling
(Institute of Electrical and Electronics Engineers Inc., 2024) Thayaba Nausheen, A.; Nakul Nayak, B.V.; Khanna, A.; Singh, M.
Nanophotonic ring resonators have emerged as promising candidates for sensing applications due to their high sensitivity and compact footprint. In this study, we investigated a 3-D aperture-coupled plasmonic microring resonator (AC-PMRR)-cum-plasmonic spectral shaper as a temperature sensor using finite-element method (FEM). The sensor operates based on the principle of the temperature-dependent refractive index change of the surrounding medium, which modulates the resonance characteristics of the microring. The aperture coupling technique enhances the sensitivity and allows efficient excitation of localized surface plasmon resonances. We analyzed the sensing performance of the proposed device through rigorous numerical simulations. The effects of various design parameters, such as ring radius, aperture size, and coupling distance, on the sensor's performance are systematically examined. Furthermore, we explore the influence of material properties and temperature range on the sensor's sensitivity and resolution. The proposed refractive index sensor demonstrates a high sensitivity of ~0.065 nm/K, the figure of merit of ~102 RIU1, and detection accuracy of ~0.32 nm1, making it suitable for various temperature sensing applications in fields such as environmental monitoring, biomedical diagnostics, and industrial process control. © 2024 IEEE.
Bed depth service time model for the biosorption of reactive red dye using the Portunus sanguinolentus shell
(2010) JagadeeshBabu, P.E.; Krishnan, R.; Singh, M.
Biosorption is an efficient and regenerative technique that often uses low-cost adsorbent materials, particularly for the treatment of wastewaters containing dyes and heavy metals. This study investigates the ability of crab shell (Portunus sanguinolentus) to remove reactive red dye in a packed bed up-flow column (internal diameter 2 cm; height 35 cm). Crab shell has high surface area (after proper size reduction) and high regenerative capacity. The experiments were performed with different bed heights (20 and 30 cm) and using different flow rates (12 and 17 ml/min) in order to obtain experimental breakthrough curves. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. The column regeneration studies were carried out for five different sorption-desorption cycles. The elutant used for the regeneration of the sorbent was 0.01 M EDTA (disodium) solution at pH 9.8 adjusted using NH4OH. This solution was found to have the best bed regeneration capacity and could be reused for several sorption-desorption cycles. The elution efficiency was greater than 99.1% in all seven cycles. Continuous use of the crab shell leads to a decrease in the adsorptive performance, as observed by the breakthrough curves becoming flatter and also because of a broader mass transfer zone. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Comparative Study of Millimeter-Wave-Over-Fiber Transmission Link with Different Photodiodes
(Institute of Electrical and Electronics Engineers Inc., 2024) Singh, A.; Mishra, S.K.; Dinesh Achalaram, C.; Singh, M.
In optical fiber communication, there is an expo- nential growth in data traffic demand. Hence, there is a need for advanced and efficient signal generation methods that offer a wider frequency range, higher tunability, and lower distortion. These optical fiber networks have long-distance capabilities and high data rates essential for intercontinental connections. This paper investigates the performance comparison of PIN photodetector and avalanche photodetector (APD) in optical fiber communication in terms of quality (Q) factor and eye patterns. The simulation model, utilizing microwave photonics (MWP) technology, implemented in OptiSystem software incorporates a Mach-Zehnder modulator (MZM) for optical signal modulation and a Bessel filter for spectral shaping. Photodetectors are susceptible to noise, which may occur due to thermal noise, shot noise, or dark current, and generate signals with increased bit error rate (BER) and degraded signal quality. To overcome these problems, photodetectors with suitable materials and designs are utilized to improve responsivity and reduce noise levels. A maximum Q factor of 7.6019 and minimum bit error rate of 1.4075 Ã— 10-14 at 10 Gbps over a 25 km single-mode optical fiber network is obtained in the mm-wave wavelength range. Theoretical analysis of the suggested system is also discussed. Â© 2024 IEEE.
Comparison of plastic collapse moment for different angled non-circular pipe bends under bending moments and internal pressure
(Springer Science and Business Media Deutschland GmbH, 2024) Kumar, M.; Singh, M.; Kumar, A.; kumar, A.; Kamble, D.L.
Pipe bends are a crucial component of the pipeline industry because they experience more stresses and deformations than straight pipes of the same dimensions and material properties under the same loading conditions. For a reliable and safe piping system, the plastic collapse moment of pipe bends must be estimated accurately. The current study aims to find which bending mode is critical to failure for pipe bends; for that, the collapse moment under in-plane closing (IPC), in-plane opening (IPO) and out-of-plane (OP) bending moments are compared using finite element (FE) analysis. The comparison accounts for various values of internal pressure, bend angle and initial geometric imperfection. The FE analysis considers elastic-perfectly plastic (EPP) and strain-hardening (SH) material models. Twice-elastic-slope (TES) method is implemented to evaluate plastic collapse moment for all considered cases. The comparison of collapse moment shows that under unpressurized conditions, pipe bends are critical to IPC bending moment. However, it is difficult to identify which bending mode is critical under pressurized conditions. Therefore, plastic collapse moment under all three bending modes should be known and for that plastic collapse moment equations under all bending modes should be proposed. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.
Complex Aware Transformer-CNN for Refractive Index Prediction in Plasmonic Waveguide
(Institute of Electrical and Electronics Engineers Inc., 2025) Chaurasia, A.R.; Marwade, V.; Singh, M.
Estimating the effective refractive index of a plasmonic waveguide with high precision is essential for various photonic applications. Traditional analytical and numerical methods often involve extensive computational methods. Deep learning-based approaches have shown promise in improving both accuracy and efficiency. This paper presents a deep learning-based approach for effective refractive index estimation using a hybrid Complex Aware Transformer-Convolutional Neural Network (CAT-CNN) model utilizing convolutional feature extraction, transformer-based attention mechanisms, and squeeze-and-excitation blocks to improve predictive accuracy. Trained on a dataset of plasmonic waveguide parameters at a fixed frequency of 193.2 THz, the model achieves a combined testing R2 score of 0.99978, demonstrating high precision in predicting the real and imaginary parts of the effective refractive index. Our results demonstrate that CAT-CNN achieves state-of-the-art performance in terms of prediction accuracy and computational efficiency. The proposed model has significant implications for the design of high-performance plasmonic sensors and integrated photonic devices. Â© 2025 IEEE.
Design and Simulation of a Terahertz Frequency Filter Based on Plasmonic SIS Waveguide Coupled with a Split Ring Resonator for Refractive Index Sensing Applications
(Springer, 2024) Thomas, S.; Singh, M.; Satyanarayan, M.N.
Terahertz waveguides and resonators have brought numerous applications from biomedical to modern communications. In this paper, we have demonstrated numerically a straight semiconductor-insulator-semiconductor(SIS) waveguide attached to a split ring resonator, which acts as a terahertz frequency filter and can be used for refractive index sensing. The device’s transmission properties have been studied using the finite element method. To fix the third dimension of the device, that is the depth of the waveguide the effective mode index and power density calculations are done for the propagating mode. The frequency tuning of the filter is achieved by changing the geometric parameters of the waveguide and resonator system such as ring radii and split width. Both the symmetric and antisymmetric modes of the split ring show almost the same rate of change of resonance frequency with the change in geometric parameters. To demonstrate the importance of the split position, the transmittance is studied by placing the split at different positions on the ring. We obtained the same transmittance for the split at left and right positions, whereas the split at the top and bottom shows different transmittance similar to the transmittance of a ring resonator. The symmetric and antisymmetric modes of the split ring are calculated for refractive index sensing and the highest sensitivity of 0.741 THz/ refractive index unit (RIU) for the symmetric mode as expected. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.
Development of low temperature stoichiometric solution combustion derived transparent conductive ternary zinc tin co-doped indium oxide electrodes
(Royal Society of Chemistry, 2017) Pujar, P.; Gandla, S.; Singh, M.; Gupta, B.; Tarafder, K.; Gupta, D.; Noh, Y.-Y.; Mandal, S.
Here, the development of transparent conductive zinc tin co-doped indium oxide (IZTO: In1.4Sn0.3Zn0.3O3) ternary electrodes is addressed through low temperature solution combustion processing. Optimization of fuel to oxidizer ratio offers low temperature (?130 °C) of combustion with balanced redox reaction. The thin films of IZTO annealed at different temperatures showed a decreasing trend in the resistivity with a fixed order of 10-2 ? cm and the film with a highest Hall mobility of 5.92 cm2 V-1 s-1 resulted at 400 °C. All the films with different temperatures of annealing were smooth (rms ? 2.42 nm) in nature and the IZTO film annealed at 200 °C is 83% transparent in the visible spectra. The effective band gap of 0.9 eV determined from first-principles density functional theory gives clear evidence for the conducting nature of IZTO. The thin film transistor fabricated with IZTO as a gate electrode with poly(methyl methacrylate) and pentacene as the dielectric and channel material, respectively, exhibited a saturation mobility of 0.44 cm2 V-1 s-1 and Ion/Ioff ratio of 103. Further, the printability of the IZTO combustible precursor is established which resulted in anti-edge deposition of the printed feature. © 2017 The Royal Society of Chemistry.
Efficient Coherent Direction-of-Arrival Estimation and Realization Using Digital Signal Processor
(Institute of Electrical and Electronics Engineers Inc., 2020) Dakulagi, V.; Alagirisamy, M.; Singh, M.
A novel efficient coherent direction-of-arrival (DOA) estimation method is devised in this article. First, a new cost function without the knowledge of source number is developed exploiting the Toeplitz matrices' joint diagonalization structure. Then, the revised steering vectors are used in the place of projection weights of the steering vectors to reconstruct the power spectrum in both noise and signal subspaces. The coherent DOAs are estimated using the 1-D search. Furthermore, the computational complexity of the proposed method is significantly reduced using the Nystrom approximation. Finally, the developed theoretical model is implemented on the TMS320C6678 digital signal processor (DSP) to exemplify the efficacy of the novel method. © 1963-2012 IEEE.
Engineering Porous Silicon-Based Plasmonic Microdisk Resonator for Highly Sensitive Methanol Sensing
(Institute of Electrical and Electronics Engineers Inc., 2024) Mehta, S.; Nakul Nayak, V.B.; Singh, M.
This study introduces a novel application of a plasmonic microdisk resonator as a highly sensitive sensor for detecting methanol vapor. Leveraging the inherent advantages of plasmonic nanostructures, the microdisk resonator demonstrates a remarkable capability to detect minute concentrations of methanol. In this work, we modeled a novel 3-D porous-silicon (p-Si)-based hybrid plasmonic aperture-coupled microdisk resonator (HPACMR) with specific dimensions and porosity to optimize the sensitivity toward methanol vapor detection. The resonator's design incorporates a thin layer of copper on a dielectric microdisk, creating a plasmonic cavity that supports localized surface plasmon resonances. Finite element method-based simulations predict strong interactions between the resonator's plasmonic field and methanol molecules, leading to detectable shifts in the resonant frequency. By tuning the layout dimensions and p-Si properties, we achieved an altitudinous sensitivity of 569.52 nm/RIU and a Q-factor of nearly 370. The sensors' miniature footprint and potential for integration into portable devices make it an attractive candidate for field-deployable applications. © 2001-2012 IEEE.
Enhanced pH Sensitivity of ISFET via TiO2 Gate Doping: A Novel Approach
(Institute of Electrical and Electronics Engineers Inc., 2025) Herur, S.M.; Sharath Balaji, T.; Singh, M.
This paper presents the simulation and analysis of an Ion-Sensitive Field-Effect Transistor (ISFET)-based pH sensor designed for accurate detection of ion concentrations through variations in gate voltage. The ISFET structure replaces the conventional gate of a MOSFET with an electrolyte and titanium dioxide (TiO2) doping, enabling the sensing of pH levels via ion-gate dielectric interactions. In this study, potassium chloride (KCl) is used as the electrolyte, and its influence on the ISFET's electrical behavior is systematically analyzed. The output characteristics, including the drain current (Id) versus drain-source voltage (Vds) under varying gate-source voltages (Vgs), are obtained using COMSOL simulation. The semiconductor and electrolyte models are meticulously coupled to ensure a realistic representation, capturing the ion-sensitive interface's behavior. A simplified global equation technique is employed to derive critical operating parameters efficiently, without explicitly modeling the feedback circuitry. The ISFET's performance is further evaluated by analyzing its sensitivity to pH variations and extracting relevant electrical characteristics for optimization. This work provides a comprehensive approach to simulating ISFET-based pH sensors, highlighting its potential for efficient and precise pH measurement in biochemical and industrial applications. Â© 2025 IEEE.
Exploring Hexagonal Boron Nitride (hBN) as a Gate Dielectric for Next-Generation MOSFETs
(Institute of Electrical and Electronics Engineers Inc., 2025) Billava, R.R.; Singh, M.
This study investigates the potential of hexagonal boron nitride (hBN) as a gate dielectric material for metal-oxide-semiconductor field-effect transistors (MOSFETs). Known for its excellent insulating properties, hBN was evaluated for its impact on device performance. A 2nm hBN layer was integrated over SiO2 in the MOSFET structure, and its output characteristics (ID-VDS) were measured across varying gate voltages (VGS). The device exhibited well-defined saturation regions, indicative of effective channel modulation, with the drain current (ID) increasing linearly with VDS in the linear region and achieving saturation, consistent with standard MOSFET behavior. The small terminal charge observed, on the order of 10-32 C, suggests a significant reduction in device capacitance due to the highly effective insulating properties of the hBN layer. This reduction in capacitance could lead to lower power consumption and faster switching speeds, making hBN an attractive candidate for next-generation transistor technologies. Â© 2025 IEEE.
Fuzzy string matching algorithm for spam detection in twitter
(2019) Kumar, A.; Singh, M.; Pais, A.R.
In recent times one of the most popular Internet activity around the world is visiting online social websites. The number of users and time spent by users on these social networks is increasing exponentially. Moreover, users tend to rely on the trustworthiness of data present on these networks. But in wrong hands this trustworthiness can easily be exploited and used to spread spams. Users can easily be harassed by spam messages which waste time and can fool users to click on malicious links. Spam effects many different type of electronic communications including instant messaging, email and social networks. But due to open nature, huge user base and reliance on users for data, social networks are worst hit because of spams. To detect spams from the social networks it is desirable to find new unsupervised techniques which can save the training cost which is required in supervised techniques. In this article we present an unsupervised, distributed and decentralized technique to detect and remove spams from social networks. We present a new technique which uses fuzzy based method to detect spams, which can detect spams even from a single message stream. To handle huge data in networks, we implement our technique to work on MapReduce platform. � Springer Nature Singapore Pte Ltd. 2019.
Fuzzy string matching algorithm for spam detection in twitter
(Springer Verlag service@springer.de, 2019) Kumar, A.; Singh, M.; Pais, A.R.
In recent times one of the most popular Internet activity around the world is visiting online social websites. The number of users and time spent by users on these social networks is increasing exponentially. Moreover, users tend to rely on the trustworthiness of data present on these networks. But in wrong hands this trustworthiness can easily be exploited and used to spread spams. Users can easily be harassed by spam messages which waste time and can fool users to click on malicious links. Spam effects many different type of electronic communications including instant messaging, email and social networks. But due to open nature, huge user base and reliance on users for data, social networks are worst hit because of spams. To detect spams from the social networks it is desirable to find new unsupervised techniques which can save the training cost which is required in supervised techniques. In this article we present an unsupervised, distributed and decentralized technique to detect and remove spams from social networks. We present a new technique which uses fuzzy based method to detect spams, which can detect spams even from a single message stream. To handle huge data in networks, we implement our technique to work on MapReduce platform. Â© Springer Nature Singapore Pte Ltd. 2019.
High sensitivity detection of chemicals based on sinusoidally apodized structured grating assisted liquid filled directional coupler
(Springer, 2021) Raghuwanshi, S.K.; Singh, Y.; Singh, M.; Chack, D.; Kumar, R.; Prakash, O.
The grating has a significant role in sensing applications. Similarly, the grating-assisted coupler has excellent potential in chemical sensing applications. The power coupling between two closely coupled waveguide couplers can be significantly tuned by incorporating grating between them. The grating has been taken of silica material with sinusoidal shape in variation. The grating layer is assumed to be embedded within the sensing layer while considering a changeable effective refractive index depending on the sensing layer substances. In the present paper, grating assisted directional coupler has been numerically analysed using its own developed MATLAB-based algorithm of finite difference method (FDM) scheme. FDM method has been applied to solve the Eigenvalue equation to obtain allowed Eigenvalues and corresponding Eigen vectors (TE and TM cases). In FDM, the analysis domain has been fine discretized into the mesh of 1-D equal spacing for reasonable accurate computation results. In experimental validation, Fibre Bragg grating (FBG) has been suspended between two high refractive index coupler regions, which act as a power coupling zone. Also, the coupling length has been changed from 5 to 20 ? m for tuning purposes and then optimized for grating parameters viz. length, period, etc. The whole structure is 2-Dimensional (x and y directions) with invariant in the y-direction. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
High Sensitivity Refractive Index Sensor Based on Indium Antimonide Terahertz Plasmonic Ring Resonator
(Institute of Electrical and Electronics Engineers Inc., 2022) Thomas, S.; Singh, M.; Satyanarayan, M.N.
A high sensitivity refractive index semiconductor-insulator-semiconductor (SIS) waveguide with a ring resonator sensor at THz frequency is proposed. The topological study of the proposed filter is numerically simulated using the finite element method. A maximum sensitivity of 0.509 THz/ Refractive index unit (RIU) is obtained by filling the air-filled ring resonator cavity with different refractive index materials. Besides that, the transmission characteristics are studied by varying the structural dimensions and observed that the system can be treated as a frequency selective device. The device gets modified by incorporating another concentric ring inside the single ring. From the transmission characteristics, the multiple modes of the concentric dual ring are studied, and concluded that the even TM1 mode shows a better response towards frequency tuning. © 2001-2012 IEEE.
High-Performance All-Optical Hybrid Plasmonic Switch Using Zn-Doped Cadmium Oxide
(Institute of Electrical and Electronics Engineers Inc., 2023) Sahu, S.K.; Singh, M.
In this article, a novel hybrid plasmonic waveguide (HPWG)-based all-optical switch (AOS) using zinc-doped cadmium oxide (ZnCdO) is reported and numerically investigated with the finite-element method. This oxide layer, which is a well-known transparent conductive oxide (TCO), can be switched from a dielectric to a metallic phase by electrical tuning the refractive index. The mobility of free-carrier concentration is highly magnified with a nonlinear optical effect induced by the epsilon-near-zero material near the telecommunication wavelength. We have simulated the plasmonic switch using the COMSOL Multiphysics simulator, predicting 13.75 dB extinction ratio (ER), 0.5 dB insertion loss (IL), and 27.5 figure-of-merit (FoM) at 1.55 \mu \text{m} wavelength. We also performed the reliability study by varying parameters, such as the width and height of the waveguide, which affect the performance of the on-chip switch design. In addition, the proposed AOS can be easily integrated with future silicon photonic circuits for ultrafast switching applications. © 1973-2012 IEEE.
High-Q Plasmonic Resonator for Volatile Organic Compound Detection
(Institute of Electrical and Electronics Engineers Inc., 2025) Mehta, S.; Shivaputra, S.; Ramesh, S.; Mandi, M.V.; Singh, M.
A hybrid plasmonic waveguide (HPWG)-based resonator designs are studied for on-chip detection of volatile organic compounds (VOCs). The HPWG, which combines dielectric and metallic layers, significantly enhances the confinement of electromagnetic field, leading to increased interaction between the guided light and the surrounding analytes. The system achieves high spectral sensitivity and narrow linewidth by integrating multiple microring resonators in a cascaded configuration. This is critical for distinguishing small changes in the refractive index (RI) associated with different VOCs. Finite element method (FEM) simulations demonstrate the superior sensing performance of a proposed device, showing a spectral sensitivity of 469.5 nm/RIU and a quality factor (QF) of 518.75. The compact design and high sensitivity make this sensor an excellent candidate for on-chip VOC monitoring in industrial safety, as well as portable breath sensors to detect VOC biomarkers for early disease diagnosis. © IEEE. 1973-2012 IEEE.