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3. Electronic structure and thermoelectric properties of epitaxial Sc1-xVxNy thin films grown on MgO(001)

Author

Chowdhury, Susmita, Singh, Niraj Kumar, Honnali, Sanath Kumar, Greczynski, Grzegorz, Eklund, Per, Febvrier, Arnaud le, and Magnuson, Martin

Subjects
Condensed Matter - Materials Science
Abstract

The electronic structure of Sc1-xVxNy epitaxial films with different alloying concentrations of V are investigated with respect to effects on thermoelectric properties. Band structure calculations on Sc0.75V0.25N indicate that V 3d states lie in the band gap of the parent ScN compound in the vicinity of the Fermi level. Thus, theoretically the presence of light (dispersive) bands at the {\Gamma}-point with band multiplicity is expected to lead to lower electrical resistivity while flat (heavy) bands at X-W-K symmetry points are associated with higher Seebeck coefficient than that of ScN. With this aim, epitaxial Sc1-xVxNy thin film samples were deposited on MgO(001) substrates. All the samples showed N substoichiometry and pseudocubic crystal structure. The N-vacancy-induced states were visible in the Sc 2p XAS spectra. The reference ScN and Sc1-xVxNy samples up to x = 0.12 were n type, exhibiting carrier concentration of 1021 cm-3, typical for degenerate semiconductors. For the highest V alloying of x = 0.15, holes became the majority charge carrier as indicated by the positive Seebeck coefficient. The underlying electronic structure and bonding mechanism in Sc1-xVxNy influence the electrical resistivity, Seebeck coefficient, and Hall effect. Thus, the work contributes to the fundamental understanding of the correlated defects and thermoelectric properties to the electronic structure in Sc-N system with V alloying., Comment: 29 pages, 8 figures, 4 tables

Published
2024

4. Effects of W alloying on the electronic structure, phase stability and thermoelectric power factor in epitaxial CrN thin films

Author

Singh, Niraj Kumar, Hjort, Victor, Honnali, Sanath Kumar, Gambino, Davide, Febvrier, Arnaud le, Ramanath, Ganpati, Alling, Björn, and Eklund, Per

Subjects
Condensed Matter - Materials Science
Abstract

CrN-based alloy thin films are of interest as thermoelectric materials for energy harvesting. Ab initio calculations show that dilute alloying of CrN with 3 at.% W substituting Cr, induce flat electronic bands and push the Fermi level EF into the conduction band, while retaining dispersive Cr 3d bands. These features are conducive for both high electrical conductivity \sigma and high Seebeck coefficient \alpha, and hence the thermoelectric power factor {\alpha}^2\sigma. To investigate this possibility, epitaxial CrWxNz films were grown on c-plane sapphire by dc-magnetron sputtering. However, even films with the lowest W concentration (x = 0.03) in our study contained metallic h-Cr2N, which is not conducive for a high \alpha. Nevertheless, the films exhibit a sizeable power factor of {\alpha}^2\sigma ~ 4.7 x 10-4 Wm-1K-2 due to high \sigma ~ 700 Scm-1, and a moderate \alpha ~ -25 ~{^^^^00b5}V/K. Increasing h-Cr2N fractions in the 0.03 < x \le 0.19 range monotonically increases \sigma, but severely diminishes \alpha leading to two orders of magnitude decrease in {\alpha}^2\sigma. This trend continues with x > 0.19 due to W precipitation. These findings indicate that dilute W additions below its solubility limit in CrN is important for realizing high thermoelectric power factor in CrWxNz alloy films.

Published
2023

7. Interaction of Acoustic and Optical Phonons in Soft Bonded Cu-Se Framework of Large Unit Cell Minerals with Anionic Disorders

Author

Rana, Kewal Singh, Gupta, Raveena, Sarkar, Debattam, Singh, Niraj Kumar, Acharya, Somnath, Vitta, Satish, Bera, Chandan, Biswas, Kanishka, and Soni, Ajay

Subjects
Condensed Matter - Materials Science, Condensed Matter - Other Condensed Matter
Abstract

Large unit cell copper-chalcogenide based minerals with high crystalline anharmonicity have a potential for thermoelectric applications owing to their inherent poor lattice thermal conductivity. Here, the softening of copper-selenium bonding and hence crystal framework plays an important role in superionic conduction and thermal conductivity. We have studied Cu26Nb2Sn6Se32, Cu26Nb2Sn6Se31.5 and Cu26Nb2Sn6Se30Te2 minerals with a strategically tailored anionic disorders. These compounds have p-type degenerate behavior with carrier concentration ranging between 1020 cm-3 at 300 K, high power factor and low lattice thermal conductivity at 640 K. The existence of two low frequency Raman active optical modes associated with soft Cu and Se atoms, three localized Einstein modes in specific heat, suggest high scattering between acoustic and optical branches with very short phonon lifetime less than 1 ps. The excess vibrational density of states at low energies with compressed and flat optical branches strongly hinders the heat transport in these crystalline mineral. Comparatively, Cu26Nb2Sn6Se30Te2 is a promising thermoelectric material because of high crystalline anharmonicity and softening of Cu-Se framework due to heavier tellurium atom., Comment: 20 Pages, 14 figures in main text and supporting information

Published
2023
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8. Anisotropic Light-Matter Interactions in Single Crystal Topological Insulator Bismuth Selenide

Author

Rawat, Divya, Singh, Aditya, Singh, Niraj Kumar, and Soni, Ajay

Subjects
Condensed Matter - Materials Science
Abstract

Anisotropy of light-matter interactions in materials give remarkable information about the phonons and their interactions with electrons. We report the angle-resolved polarized Raman spectroscopy of single-crystal of Bi2Se3 to obtain the elements of Raman tensor for understanding the strength of polarization along different crystallographic orientations. Intensity variation in the polar plots corresponding to E_g^1 ~ 37 cm-1, A_1g^1 ~71 cm-1, E_g^2 ~ 130 cm-1, and A_1g^2 ~ 173 cm-1 suggests the higher differential polarizability along cross-plane (bc-plane). The polar patterns and the differences in elements of the Raman tensor provides the evidence of the fundamental electron-phonon and anisotropic light matter interactions in Bi2Se3., Comment: 11 pages and 4 figures

Published
2023
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11. List of contributors

Author

Aizawa, Shin-Ichi, primary, Alberdi, Pilar, additional, Alexander, David C., additional, Alía, Alberto, additional, Allison, D.G., additional, Amyes, Sebastian G.B., additional, An, Haoran, additional, Andrade, María J., additional, Antelmann, Haike, additional, Arias, Cesar A., additional, Asensio, Miguel A., additional, Axell-House, Dierdre B., additional, Bae, Hee-Won, additional, Baena, Laura Muñoz, additional, Baig, Abdul Mannan, additional, Bailey, Spenser O., additional, Baize, Sylvain, additional, Baldi, Pablo C., additional, Barbosa, Angela Silva, additional, Barbuddhe, Sukhadeo B., additional, Bard, Emilie, additional, Barry, Eileen M., additional, Basarab, Gregory S., additional, Beloborodova, N.V, additional, Bermúdez, Elena, additional, Bidmos, Fadil A., additional, Bisgaard, Magne, additional, Blakely, Garry W., additional, Bloch, Evan, additional, Boesen, Thias Oberg, additional, Bose, Dipayan, additional, Botero, Javier Enrique, additional, Bouabe, Hicham, additional, Bouchard, Michael J., additional, Bozue, Joel A., additional, Bradbury, Richard S., additional, Brett Moreau, G., additional, Cabezas-Cruz, Alejandro, additional, Cai, Rong-Jun, additional, Calderón, Enrique J., additional, Cao, Boyang, additional, Carmena, David, additional, Carvalho, Eneas, additional, Caulfield, Amanda D., additional, Cen, Shan, additional, Chai, Jong-Yil, additional, Chamberland, Robin R., additional, Champredon, David, additional, Chan, Edward D., additional, Charbon, Godefroid, additional, Chato, Connor, additional, Chelomina, G.N., additional, Chen, Jingyu, additional, Chen, Min, additional, Chen, Shuyu, additional, Chen, Suilin, additional, Chen, Yanfei, additional, Chen, Zhaoyuan, additional, Cheng, Aimin, additional, Cheng, Keding, additional, Chiu, Charles Y., additional, Cho, You-Hee, additional, Christensen, Henrik, additional, Chrtdernevskaya, E.A., additional, Contreras, Adolfo, additional, Contreras, Marinela, additional, Córdoba, Juan J., additional, Córdoba, María G., additional, Costa, Rita, additional, Cote, Christopher K., additional, Cui, Xiangling, additional, Cui, Yujun, additional, Dacal, Elena, additional, Dammann, Allison N., additional, Das, Shubhagata, additional, Dashti, Alejandro, additional, de la Fuente, José, additional, de la Garza, Mireya, additional, Delgado, Josué, additional, Delgado-Cuesta, Juan, additional, Deng, Haiteng, additional, Deng, Li, additional, Dey, Debajit, additional, Dhama, Kuldeep, additional, Diego, Juan García-Bernalt, additional, Ding, Hao, additional, Doern, Christopher D., additional, Dorman, Charles J., additional, Du, Zongmin, additional, Dunbar, Sherry A., additional, Duthie, Malcolm, additional, Dybvig, Kevin F., additional, Eakin, Ann E., additional, Eallonardo, Samuel J., additional, Eberly, Allison R., additional, Echeverry, Adriana Jaramillo, additional, Egland, Paul G., additional, El Zowalaty, Mohamed E., additional, Endsley, Janice Jones, additional, Eom, Keeseon S., additional, Evans, Benjamin A., additional, Falkinham, Joseph O., additional, Feng, Siwei, additional, Feng, Yaoyu, additional, Feng, Zongdi, additional, Fernández-Soto, Pedro, additional, Ferreira, Roux-Cil, additional, Flores-Huerta, Nadia, additional, Foster, Timothy J., additional, Fox-Moon, Sandra M., additional, Fraga, Tatiana Rodrigues, additional, Fredricks, David N., additional, Freitag, Nancy E., additional, Frimodt-Møller, Jakob, additional, Fuller, Risa, additional, Ganesh, Balasubramanian, additional, Gao, Ning, additional, García-Carnero, Laura C., additional, Garzetti, Debora, additional, Geoghegan, Joan A., additional, Ghenim, Raed, additional, Giambartolomei, Guillermo H., additional, Gilbert, Nicole M., additional, Gillis, Thomas Phillip, additional, Gladstone, Camilla A., additional, Gómez-Gaviria, Manuela, additional, Gómez-Marín, Jorge E., additional, Gong, Tengfang, additional, González, Ramón A., additional, Gray-Owen, Scott D., additional, Gu, Bing, additional, Guzmán-Téllez, Paula, additional, Hajal, Caroline, additional, Han, Yanping, additional, Hao, Yi, additional, Harrington, Amanda T., additional, Harris, Jason B., additional, Harvill, Eric T., additional, Hasan, S. Saif, additional, He, Guang-Jun, additional, He, Yongqun, additional, Heffron, Jared D., additional, Hidalgo, Paloma, additional, Hindiyeh, Musa Y., additional, Hreha, Teri N., additional, Hu, Xiaoyu, additional, Huang, Guanghua, additional, Huang, Jiangqing, additional, Huang, Liang, additional, Huang, Shifeng, additional, Huang, Xingxu, additional, Huang, Xueting, additional, Huang, Yilun, additional, Huffman, Anthony, additional, Humphreys, Tricia L., additional, Hunstad, David A., additional, Inglis, Timothy J.J., additional, Isaac, Lourdes, additional, Jacobs, Samantha E., additional, Janowicz, Diane M., additional, Jeon, Hyeong-Kyu, additional, Ji, Quanjiang, additional, Jia, Qi, additional, Jia, Wei, additional, Jin, Shouguang, additional, Jneidi, Lama, additional, Jose, Shinsmon, additional, Jung, Bong-Kwang, additional, Kattan, Randa, additional, Kaushik, Rahul, additional, Khare, Reeti, additional, Kim, Eun Sook, additional, Kirn, Thomas J., additional, Koo, Hyun, additional, Köster, Pamela C., additional, Krause, Peter J., additional, Kumar, Sanjai, additional, Kupz, Andreas, additional, Lambert, P.A., additional, Lamont, Richard J., additional, Langford, Paul R., additional, Lebeaux, David, additional, Legname, Giuseppe, additional, Li, Bin, additional, Li, Chunhao, additional, Li, Fen, additional, Li, Jun, additional, Li, Lanjuan, additional, Li, Ruofan, additional, Li, Ruoyu, additional, Li, Ting, additional, Li, Yang-Yang, additional, Li, Yanhua, additional, Li, Zhuorong, additional, Liang, Xiaomeng, additional, Liao, Guojian, additional, Lin, Ping, additional, Ling, Yun, additional, Liu, Bo, additional, Liu, Dongyou, additional, Liu, Guohua, additional, Liu, Huidi, additional, Liu, Jiafeng, additional, Liu, Jintao, additional, Liu, Qi, additional, Liu, Shu-Lin, additional, Liu, Taiping, additional, Liu, Tongbao, additional, Liu, Wei, additional, Liu, Yan, additional, Liu, Yanni, additional, Liu, Yisong, additional, Liu, Yuan, additional, Løbner-Olesen, Anders, additional, Loeffelholz, Michael, additional, Lu, Hongzhou, additional, Luna, Brian, additional, Ma, Bingting, additional, Ma, Chengying, additional, Ma, Shuang, additional, Ma, TianLi, additional, Madan, Rajat, additional, Mahle, Rachael E., additional, Mahlen, Steven D., additional, Malik, Satya Veer Singh, additional, Malik, Yashpal Singh, additional, Malvy, Denis, additional, Mann, Barbara J., additional, Marasini, Daya, additional, Maris, Alexander S., additional, Marjomäki, Varpu, additional, Marjuki, Henju, additional, Martín, Alberto, additional, Martín, Irene, additional, Martínez-Castillo, Moisés, additional, Martínez-Pabón, María Cecilia, additional, Mathison, Blaine A., additional, Ma’ayeh, Showgy, additional, McDowell, Andrew, additional, McLaughlin, Stephanie E., additional, McSheffrey, Gordon G., additional, Medrano, Francisco J., additional, Meehan, Conor J., additional, Mehta, Dhwani, additional, Mejía-Oquendo, Manuela, additional, Melo-Cristino, José, additional, Mendoza-Barberá, Elena, additional, Meng, Xinan, additional, Merino, Susana, additional, Merritt, Adam J., additional, Miller, Steve, additional, Miller, William R., additional, Minamino, Tohru, additional, Mirzaei, Mohammadali Khan, additional, Mora-Montes, Héctor M., additional, Mortensen, Joel, additional, Mostafa, Heba H., additional, Muhsen, Khitam, additional, Mujahed, Ahlam, additional, Muro, Antonio, additional, Murphy, Olwen C., additional, Newton, Hayley J., additional, Nguyen, April H., additional, Nichols, Wright W., additional, Niu, Siqiang, additional, Núñez, Félix, additional, Obregon, Dasiel, additional, Okamoto, Akira, additional, Okutani, Akiko, additional, Olabode, Abayomi, additional, Omar, Muna, additional, Ong, Edison, additional, Ouyang, Zhiming, additional, Pacak, Christina A., additional, Pacheco-Yépez, Judith, additional, Palmer, John, additional, Pang, Xiaoli, additional, Paredes-Sabja, Daniel, additional, Peng, Zhong, additional, Peng, Zonggen, additional, Pérez-Nevado, Francisco, additional, Poon, Art, additional, Pospíšilová, Petra, additional, Potts, Caelin C., additional, Pu, Qinqin, additional, Pujic, Petar, additional, Qi, Rui, additional, Qian, Chenyun, additional, Qian, Liu, additional, Qin, Aiping, additional, Qu, Fen, additional, Rakin, Alexander, additional, Ramesh, Ashwin, additional, Ramirez, Mario, additional, Rao, Yu, additional, Ratner, Adam J., additional, Rawool, Deepak B., additional, Rehman, Asma, additional, Ren, Jie, additional, Ren, Ping, additional, Retchless, Adam C., additional, Robertson, Erle S., additional, Rodríguez, Alicia, additional, Rodriguez, Azucena, additional, Rodríguez-Medina, Carolina, additional, Rodriguez-Nava, Veronica, additional, Rohde, Manfred, additional, Romero-Rodríguez, Alba, additional, Rosales-Morgan, Gabriela, additional, Rosenkranz, Andrea L., additional, Ruiz-Moyano, Santiago, additional, Ruokolainen, Visa, additional, Sabateen, Ali, additional, Sahu, Radhakrishna, additional, Sails, Andrew, additional, Sang, Yu, additional, Santana, Clarissa H., additional, Santos, Jesus A., additional, Santos, Renato L., additional, Schmitz, Jonathan E., additional, Serrano-Luna, Jesús, additional, Shen, Jianzhong, additional, Shen, Zhangqi, additional, Shibayama, Mineko, additional, Shirtliff, Mark E., additional, Silva-Costa, Catarina, additional, Silva-Olivares, Angélica, additional, Singh, Niraj Kumar, additional, Šmajs, David, additional, Smith, Robert P., additional, Smith, Sophie, additional, Snyder, Lori A.S., additional, Song, Yinggai, additional, Soro, Aurea Simon, additional, Spearman, Paul, additional, Spellberg, Brad, additional, Sprague, Lisa D., additional, Stratton, Charles W., additional, Strenk, Susan M., additional, Strugnell, Richard A., additional, Sun, Keer, additional, Suo, Xun, additional, Suzuki-Hatano, Silveli, additional, Svärd, Staffan, additional, Talbot, Elizabeth A., additional, Tamez-Castrellón, Alma K., additional, Tan, Nie, additional, Tang, Cynthia Y., additional, Tang, Yi-Wei, additional, Tao, Jia, additional, Tao, Lili, additional, Terrero-Salcedo, David, additional, Tharmalingam, Jayaraman, additional, Thwe, Phyu M., additional, Tiamani, Kawtar, additional, Tomás, Juan M., additional, Topaz, Nadav, additional, Tsai, Ang-Chen, additional, Tsalik, Ephraim L., additional, Tuomanen, Elaine I., additional, Turenne, Christine Y., additional, Tyagi, Anuj, additional, Uprety, Priyanka, additional, Valour, Florent, additional, van Hensbergen, Vincent P., additional, Venkatesan, Arun, additional, Vergis, Jess, additional, Villar, Margarita, additional, Vollmer, Waldemar, additional, Waites, Ken B., additional, Wan, Xiu-Feng, additional, Wang, Guiqing, additional, Wang, Lijun, additional, Wang, Lin, additional, Wang, Linqi, additional, Wang, Xiangru, additional, Wang, Xin, additional, Wang, Xinjie, additional, Wang, Ya-Ting, additional, Wang, Yang, additional, Wang, Yating, additional, Weil, Ana A., additional, Welkos, Susan L., additional, Wengenack, Nancy L., additional, Westblade, Lars F., additional, Whitfield, Chris, additional, Wu, Hui, additional, Wu, Lijuan, additional, Wu, Min, additional, Wu, Yarong, additional, Wu, Zhaowei, additional, Xiang, Ye, additional, Xiao, Di, additional, Xiao, Li, additional, Xiao, Lihua, additional, Xu, Tao, additional, Xu, Wenyue, additional, Xu, Xinping, additional, Xue, Jinling, additional, Yadav, Jay Prakash, additional, Yan, Junxiang, additional, Yan, Yixin, additional, Yang, Changmei, additional, Yang, Ruifu, additional, Yang, Ying, additional, Yao, Kaihu, additional, Yao, Yu-Feng, additional, Yeakle, Kyle C., additional, Yu, Demin, additional, Yu, Hao, additional, Yu, Xue-Jie, additional, Yuan, Zhenghong, additional, Zai, Wenjing, additional, Zhang, Jianzhong, additional, Zhang, Jing-Ren, additional, Zhang, Lanyue, additional, Zhang, Lijie, additional, Zhang, Qiwei, additional, Zhang, Wenbao, additional, Zhang, Wenhong, additional, Zhang, Xinxin, additional, Zhao, Youbao, additional, Zhou, Chuanmin, additional, Zhu, Feng, additional, Zhu, Jingting, additional, and Zhu, Yongqun, additional

Published
2024
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12. COVID-19: etiology

Author

Singh, Niraj Kumar, primary, Tyagi, Anuj, additional, Ganesh, Balasubramanian, additional, Kaushik, Rahul, additional, El Zowalaty, Mohamed E., additional, Dhama, Kuldeep, additional, and Malik, Yashpal Singh, additional

Published
2024
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15. Ultralow Thermal Conductivity and Thermoelectric Properties of Bi4GeTe7 with an Intrinsic van der Waal Heterostructure

Author

Singh, Niraj Kumar, Kashyap, Ankit, and Soni, Ajay

Subjects
Condensed Matter - Materials Science
Abstract

Ternary chalcogenides, having large crystalline unit cell and van der Waal stacking of layers, are expected to be poor thermal conductors and good thermoelectric (TE) materials. We are reporting that layered Bi4GeTe7, with alternating quintuplet-septuplet layers of Bi2Te3 and Bi2GeTe4, has an ultralow thermal conductivity, \k{appa}total 0.42 Wm-1K-1 because of high degree of anharmonicity as estimated from large Gruneisen parameter ({\gamma} 4.07) and low Debye temperature ({\theta}d 135 K). The electron dominated charge transport has been realized from the Seebeck coefficient, S - 82 uV/K, at 380 K, and Hall carrier concentration of ne ~ 9.8 x 1019 cm-3 at 300 K. Observation of weak antilocalization (WAL), due to spin-orbit coupling (SOC) of heavy Bi and Te, advocate Bi4GeTe7 to be a topological quantum material also. The cross-sectional transmission electron microscopy images show the inherent stacking of hetero-layers, which are leading to a large anharmonicity for poor phonon propagation. Thus, being a poor thermal conductor with a TE figure of merit, ZT ~ 0.24, at 380 K, the Bi4GeTe7 is a good material for TE applications.

Published
2021
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16. Electron-Phonon Coupling and Quantum Correction to Topological Magnetoconductivity in Bi2GeTe4

Author

Singh, Niraj Kumar, Rawat, Divya, Dey, Dibyendu, Elsukova, Anna, Persson, Per O. Å., Eklund, Per, Taraphder, A., and Soni, Ajay

Subjects
Condensed Matter - Materials Science
Abstract

We report on structure, vibrational properties and weak-antilocalization-(WAL-) induced quantum correction to magnetoconductivity in single crystal Bi2GeTe4. Surface band structure calculations show a single Dirac cone corresponding to topological surface states in Bi2GeTe4. An estimated phase coherence length, l_{\phi} ~ 143 nm and prefactor {\alpha} ~ - 1.54 from Hikami-Larkin-Nagaoka fitting of magnetoconductivity describe the quantum correction to conductivity. An anomalous temperature dependence of A1g Raman modes confirms enhanced electron-phonon interactions. Our results establish the involvement of vibrations of Bi-Te with existence of topological surface states and WAL in Bi2GeTe4.

Published
2021
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17. Subcortical and Cortical Electrophysiological Measures in Children with Speech-in-Noise Deficits Associated with Auditory Processing Disorders

Author

Hussain, Reesha Oovattil, Kumar, Prawin, and Singh, Niraj Kumar

Abstract

Purpose: The aim of this study was to analyze the subcortical and cortical auditory evoked potentials for speech stimuli in children with speech-in-noise (SIN) deficits associated with auditory processing disorder (APD) without any reading or language deficits. Method: The study included 20 children in the age range of 9-13 years. Ten children were recruited to the APD group; they had below-normal scores on the speech-perception-in-noise test and were diagnosed as having APD. The remaining 10 were typically developing (TD) children and were recruited to the TD group. Speech-evoked subcortical (brainstem) and cortical (auditory late latency) responses were recorded and compared across both groups. Results: The results showed a statistically significant reduction in the amplitudes of the subcortical potentials (both for stimulus in quiet and in noise) and the magnitudes of the spectral components (fundamental frequency and the second formant) in children with SIN deficits in the APD group compared to the TD group. In addition, the APD group displayed enhanced amplitudes of the cortical potentials compared to the TD group. Conclusion: Children with SIN deficits associated with APD exhibited impaired coding/processing of the auditory information at the level of the brainstem and the auditory cortex.

Published
2022
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22. Subcortical and Cortical Electrophysiological Measures in Children With Speech-in-Noise Deficits Associated With Auditory Processing Disorders

Author

Hussain, Reesha Oovattil, Kumar, Prawin, and Singh, Niraj Kumar

Subjects
Speech perception -- Analysis, Neurophysiology -- Analysis, Health
Abstract

Purpose: The aim of this study was to analyze the subcortical and cortical auditory evoked potentials for speech stimuli in children with speech-in-noise (SIN) deficits associated with auditory processing disorder (APD) without any reading or language deficits. Method: The study included 20 children in the age range of 9-13 years. Ten children were recruited to the APD group; they had below-normal scores on the speech-perception-in-noise test and were diagnosed as having APD. The remaining 10 were typically developing (TD) children and were recruited to the TD group. Speech-evoked subcortical (brainstem) and cortical (auditory late latency) responses were recorded and compared across both groups. Results: The results showed a statistically significant reduction in the amplitudes of the subcortical potentials (both for stimulus in quiet and in noise) and the magnitudes of the spectral components (fundamental frequency and the second formant) in children with SIN deficits in the APD group compared to the TD group. In addition, the APD group displayed enhanced amplitudes of the cortical potentials compared to the TD group. Conclusion: Children with SIN deficits associated with APD exhibited impaired coding/processing of the auditory information at the level of the brainstem and the auditory cortex. Supplemental Material: https://doi.org/10.23641/asha.21357735, Speech perception in the presence of background noise is one of the key auditory processing skills individuals utilize in their everyday life. The underlying auditory process of the same is [...]

Published
2022
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34. An early assessment of subjective well-being in an undergraduate by using heterogeneous stacked ensemble.

Author

Upadhyay, Devesh Kumar, Mohapatra, Subrajeet, and Singh, Niraj Kumar

Subjects
SUBJECTIVE well-being (Psychology), MACHINE learning, LIFE satisfaction, UNDERGRADUATES, SOCIAL services, MACHINE theory
Abstract

Subjective Well-Being (SWB) is a significant indicator of undergraduate students' life satisfaction and social welfare. Machine learning is gaining increasing prominence as a valuable tool in various fields. However, limited studies have employed machine learning techniques to explore SWB. To predict Subjective Well-Being among undergraduate students, this paper introduces a Heterogeneous Stacked Ensemble classifier model, which combines XGBoost, SVM GridSearch, LR, LightGBM, Bayes Net, and CatBoost classifiers. Additionally, the feature importance index derived from tree models is utilized to uncover shifts in the key factors influencing SWB. The results indicate that the stacking model proposed in this study surpasses traditional models like LR and other standalone machine learning models regarding predictive accuracy. Furthermore, the findings shed light on common factors contributing to SWB over time. The methods employed in this research demonstrate effectiveness, and the outcomes endorse endeavours aimed at fostering a more harmonious society. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Design and Analysis of RS Sort

Author

Ranjan, Harsh, Agarwal, Sumit, and Singh, Niraj Kumar

Subjects
Computer Science - Data Structures and Algorithms, 68P10
Abstract

This paper introduces a new comparison base stable sorting algorithm, named RS sort. RS Sort involves only the comparison of pair of elements in an array which ultimately sorts the array and does not involve the comparison of each element with every other element. RS sort tries to build upon the relationship established between the elements in each pass. Suppose there is an array containing three elements a1, a2, a3 and if a relationship exist such that a1

Published
2014

49. A Statistical Peek into Average Case Complexity

Author

Singh, Niraj Kumar, Chakraborty, Soubhik, and Mallick, Dheeresh Kumar

Subjects
Computer Science - Data Structures and Algorithms, Statistics - Applications
Abstract

The present paper gives a statistical adventure towards exploring the average case complexity behavior of computer algorithms. Rather than following the traditional count based analytical (pen and paper) approach, we instead talk in terms of the weight based analysis that permits mixing of distinct operations into a conceptual bound called the statistical bound and its empirical estimate, the so called "empirical O". Based on careful analysis of the results obtained, we have introduced two new conjectures in the domain of algorithmic analysis. The analytical way of average case analysis falls flat when it comes to a data model for which the expectation does not exist (e.g. Cauchy distribution for continuous input data and certain discrete distribution inputs as those studied in the paper). The empirical side of our approach, with a thrust in computer experiments and applied statistics in its paradigm, lends a helping hand by complimenting and supplementing its theoretical counterpart. Computer science is or at least has aspects of an experimental science as well, and hence hopefully, our statistical findings will be equally recognized among theoretical scientists as well.

Published
2013

50. Contributors

Author

Adil, Laxmi Raman, primary, Afroz, Mohammad Adil, additional, Arunagirinathan, Rahul Narasimhan, additional, Baisnab, Dipak Kumar, additional, Baradaran, Maryam, additional, Barquinha, Pedro, additional, Basu, Soumen, additional, Bera, Santanu, additional, Betancur, Rafael, additional, Bhattacharya, Shantanu, additional, Blachowicz, Tomasz, additional, Błaszczyk, Alfred, additional, Branquinho, Rita, additional, Carlos, Emanuel, additional, Chakraborty, Indranil, additional, Chang, Chih-hung, additional, Choudhury, Anwesha, additional, Chourasia, Nitesh K., additional, Curto, Vincenzo F., additional, Das, Sachindranath, additional, Das, Soumen, additional, de Zea Bermudez, V., additional, Di Maria, Francesca, additional, Ehrmann, Andrea, additional, Fernandes, M., additional, Fortunato, Elvira, additional, Gao, Zhongwei, additional, Garai, Rabindranath, additional, Ghodsi, Farhad E., additional, Ghose, Srabantika, additional, Gupta, Ritesh Kant, additional, Hossain, Maimur, additional, Huang, Ho-Chun, additional, Iyer, Parameswar Krishnan, additional, Jaramillo, Franklin, additional, Kaminski Schierle, Gabriele S., additional, Kashyap, Ankit, additional, Laia, César A.T., additional, Maia, Marta, additional, Maji, Debashis, additional, Majumder, Deblina, additional, Malliaras, George G., additional, Mandal, Kalyan, additional, Mandal, Madhuri, additional, Martins, Rodrigo, additional, Middya, Sagnik, additional, Mondal, Subrata, additional, Montoya, Juan F., additional, Moreira, Tiago, additional, Mukherjee, Supratim, additional, Omar, Shobit, additional, Onna, D., additional, Pal, Bhola N., additional, Pal, Nila, additional, Pan, Changqing, additional, Panda, Subhendu K., additional, Pandey, Mohit, additional, Parola, António Jorge, additional, Ramirez, Daniel, additional, Rana, Dhiraj Kumar, additional, Rashiku, Mohammed, additional, Saha, Samik, additional, Shen, Ming-Huei, additional, Singh, Niraj Kumar, additional, Soler-Illia, G.J.A.A., additional, Soni, Ajay, additional, Soni, Mahesh, additional, Su, Yu-Wei, additional, Talukdar, Souvanik, additional, Tanwar, Arvin Sain, additional, Vásquez-Montoya, Manuel, additional, Vensaus, P., additional, Yang, Yu-Hsuan, additional, Yathirajula, Ramesh Babu, additional, Zangoli, Mattia, additional, and Zehra, Nehal, additional

Published
2021
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