Markov Chain Monte Carlo simulation based Bayesian updating of model parameters and their uncertainties

Partha Sengupta,Subrata Chakraborty 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.1

The prediction error variances for frequencies are usually considered as unknown in the Bayesian system identification process. However, the error variances for mode shapes are taken as known to reduce the dimension of an identification problem. The present study attempts to explore the effectiveness of Bayesian approach of model parameters updating using Markov Chain Monte Carlo (MCMC) technique considering the prediction error variances for both the frequencies and mode shapes. To remove the ergodicity of Markov Chain, the posterior distribution is obtained by Gaussian Random walk over the proposal distribution. The prior distributions of prediction error variances of modal evidences are implemented through inverse gamma distribution to assess the effectiveness of estimation of posterior values of model parameters. The issue of incomplete data that makes the problem ill-conditioned and the associated singularity problem is prudently dealt in by adopting a regularization technique. The proposed approach is demonstrated numerically by considering an eight-storey frame model with both complete and incomplete modal data sets. Further, to study the effectiveness of the proposed approach, a comparative study with regard to accuracy and computational efficacy of the proposed approach is made with the Sequential Monte Carlo approach of model parameter updating.

Reverse Bias Leakage Current Mechanism of AlGaN/InGaN/GaN Heterostructure

Apurba Chakraborty,Saptarsi Ghosh,Partha Mukhopadhyay,Sanjay K. Jana,Syed Mukulika Dinara,Ankush Bag,Mihir K. Mahata,Rahul Kumar,Subhashis Das,Palash Das,Dhrubes Biswas 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.2

The reverse bias leakage current mechanism of AlGaN/InGaN/GaNheterostructure is investigated by current-voltage measurement intemperature range from 298 K to 423 K. The Higher electric field acrossthe AlGaN barrier layer of AlGaN/InGaN/GaN double heterostructuredue to higher polarization charge is found to be responsible for strongFowler-Nordheim (FN) tunnelling in the electric field higher than3.66 MV/cm. For electric field less than 3.56 MV/cm, the reverse biasleakage current is also found to follow the trap assisted Frenkel-Poole(FP) emission in low negative bias region. Analysis of reverse FPemission yielded the barrier height of trap energy level of 0.34 eV withrespect to Fermi level.

Combining Ability for Morphological and Biochemical Characters in Mulberry (Morns spp.) under Salinity Stress

Vijayan, Kunjupillai,Chakraborti, Shyama Prasad,Doss, Subramaniam Gandhi,Ghosh, Partha Deb,Ercisli, Sezai Korean Society of Sericultural Science 2008 International Journal of Industrial Entomology Vol.16 No.2

A line x tester analysis was carried out in mulberry (Morns spp.) under different salinity levels to determine the changes in the genetic interaction of various morpho-biochemical characters. Five mulberry genotypes, 3 females and 2 males, differing in salt tolerance were selected for the study. Clones of these parents along with clones of the F1 hybrids were planted in earthen pots and subjected to different levels of salinity (0.0%, 0.25%, 0.50%, 0.75% and 1.00% NaCl). Data on morphological and biochemical characters were subjected to line x tester analysis. The result revealed significant variation among the parents studied. The prominence of non-additive gene effect under control condition suggests the need for well chalked out breeding program to exploit the non-fixable variance of components for improvement of plant height, leaf size and leaf yield, chlorophyll and photosynthesis in mulberry. However, under salinity stress a shift from non-additive gene effect to additive gene effect for the above said character further suggests the need for a change in breeding strategy. The general combining ability (GCA) analysis has identified English black as the best combiner among the parents and the specific combining ability analysis (SCA) found crosses of English black X C776 and Rotndiloba x Mandalaya were good for Plant height and leaf size and English black X C776 and Rotundiloba x C776 were good for biochemical proline and chlorophyll. From the performance of parents and their crosses under different salinity levels and also under normal cultural conditions it is concluded that in mulberry different approaches are required to develop varieties for the irrigated and saline conditions.

A modified Waldron test based on sliding skewness for determining asymmetric cycle in a turbidite section

Basab Mukhopadhyay,Partha Pratim Chakraborty,Tapan Majumder 한국지질과학협의회 2004 Geosciences Journal Vol.8 No.2

The non-parametric ‘sign-of-difference’ Waldron test, conventionally used for identifying asymmetric cyclicity (thinningor thickening-up) in turbidite successions, often fails to offer convincing results either when bed thickness distribution is lognormal or where positive and negative cycles are present in equal abundance. A modified Waldron test based on sliding skewness method (taking a number of bed thickness at a time) is proposed here for determining asymmetric cycles in turbidite successions, which appears to be random in their bed thickness distribution based on conventional Waldron test. The method has been tested on two turbidite sections, which belong to two different settings of a single submarine fan system (Andaman Flysch Fan) that is known to have a lognormal bed thickness distribution. Application of the sliding skewness methodology reveals thinning-upward asymmetric cycles in both of these sections, which corroborate with the field observations and paleoenvironmental interpretations. Statistical significance for the proposed methodology was determined on the studied sections both through the Z-value and appropriate two-tailed null hypothesis. It is proposed that the result (thickening or thinning upward) is invariant with the interval (number of bed thickness taken for calculation) chosen for the sliding skewness calculation. This new method can be used on bed thickness measurement data from any turbidite succession in addition to other tests for identifying asymmetric cyclicity where non-parametric Waldron Test fails.

Evolution and Analysis of Nitride Surface and Interfaces by Statistical Techniques: A Correlation with RHEED through Kinetic Roughening

Ankush Bag,Rahul Kumar,Partha Mukhopadhyay,Mihir K. Mahata,Apurba Chakraborty,Saptarsi Ghosh,Sanjay K. Jana,Dhrubes Biswas 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.4

In-situ RHEED and ex-situ AFM characterizations have been employed to investigate transformations of surface topography with the thickness of PAMBE grown AlGaN and InGaN on GaN. The ternary alloys have been grown with identical growth-front roughness as confirmed by XRR and RHEED observations. The spottier RHEED has been observed with increased thickness of the InGaN as opposed to streakier behavior of AlGaN. We have noticed incremental nature of RMS roughness, skewness and kurtosis of InGaN surface compared to GaN or AlGaN from AFM as evident by final spotty RHEED for InGaN. However, the analyzed fractal dimension is lower for InGaN as opposed to AlGaN ( ). From the kinetic roughening perspective of adatoms, the experimental evidences lead to the high correlation between binding energy of the cluster atoms ( ) and the modified DDA growth model with dissociation and evaporation to confirm the efficacy of the study. The initial streaky and spotty RHEED of InGaN and AlGaN, respectively, can be attributed to their Eb that causes smoothing and roughening of the GaN surface due to adatoms surface mobility behavior. Therefore, the fractal description reveals the fact during formation of nitride hetero-interface while other AFM results describe the top surface.

Research Articles : Combining Ability for Morphological and Biochemical Characters in Mulberry (Morus spp.) under Salinity Stress

( Kunjupillai Vijayan ),( Shyama Prasad Chakraborti ),( Subramaniam Gandhi Doss ),( Partha Deb Ghosh ),( Sezai Ercisli ) 한국잠사학회 2008 International Journal of Industrial Entomology Vol.16 No.2

A line x tester analysis was carried out in mulberry (Morus spp.) under different salinity levels to determine the changes in the genetic interaction of various morpho-biochemical characters. Five mulberry genotypes, 3 females and 2 males, differing in salt tolerance were selected for the study. Clones of these parents along with clones of the F1 hybrids were planted in earthen pots and subjected to different levels of salinity (0.0%, 0.25%, 0.50%, 0.75% and 1.00% NaCl). Data on morphological and biochemical characters were subjected to line x tester analysis. The result revealed significant variation among the parents studied. The prominence of non-additive gene effect under control condition suggests the need for well chalked out breeding program to exploit the non-fixable variance of components for improvement of plant height, leaf size and leaf yield, chlorophyll and photosynthesis in mulberry. However, under salinity stress a shift from non-additive gene effect to additive gene effect for the above said character further suggests the need for a change in breeding strategy. The general combining ability (GCA) analysis has identified English black as the best combiner among the parents and the specific combining ability analysis (SCA) found crosses of English black X C776 and Rotndiloba x Mandalaya were good for Plant height and leaf size and English black X C776 and Rotundiloba x C776 were good for biochemical proline and chlorophyll. From the performance of parents and their crosses under different salinity levels and also under normal cultural conditions it is concluded that in mulberry different approaches are required to develop varieties for the irrigated and saline conditions.

Unusual Uptake of Prostate Specific Tracer ⁶⁸Ga-PSMA-HBED-CC in a Benign Thyroid Nodule

Damle, Nishikant Avinash,Tripathi, Madhavi,Chakraborty, Partha Sarathi,Sahoo, Manas Kumar,Bal, Chandrasekhar,Aggarwal, Shipra,Arora, Geetanjali,Kumar, Praveen,Kumar, Rajeev,Gupta, Ravikant The Korea Society of Nuclear Medicine 2016 핵의학 분자영상 Vol.50 No.4

$^{68}Ga$-Prostate specific membrane antigen- N,N′-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N′-diacetic acid- positron emission tomography/computed tomography or 68 Ga- HBED-CC-PSMA PET/CT, popularly known as PSMA PET/CT, is able to detect a small volume of recurrent prostate carcinoma (PC) when there is a prostate specific antigen (PSA) rise on follow-up after prostatectomy or other definitive treatment for PC. The use of PSMA PET/CT in the initial staging in PC is uncertain at this time. Clinical studies are underway to define its exact role in the management of the disease. At the same time it is important to be aware of unexpected sites of uptake of this ligand. We present here the case of a 62-year-old male patient who underwent prostatectomy for adenocarcinoma prostate. He also had a long-standing left solitary thyroid nodule (STN). Four months after surgery, he had a rising trend in serum PSA levels on three occasions, but the absolute value was less than 4 at all times. He underwent a $^{68}Ga$-PSMA-HBED-CC PET/CT, but it did not reveal any recurrent/metastatic site of disease. However, there was increased tracer uptake in the left STN. Fine needle aspiration cytology revealed features of atypia of undetermined significance, Bethesda category III. The patient underwent a left hemithyroidectomy and the histopathology showed features of a follicular adenoma.

Ascertaining polarity of public opinions on Bangladesh cricket using machine learning techniques

Faruque M. Abdullah,Rahman Saifur,Chakraborty Partha,Choudhury Tanupriya,Um Jung-Sup,Singh Thipendra Pal 대한공간정보학회 2022 Spatial Information Research Vol.30 No.2

In the present world, we are not only the consumers of information but creators as well. The virtual world of social media, which is considered a free open forum for discussion; provides its participants a chance to shape or re-shape the digital information by expressing opinions. These opinions generally contain different types of sentiments. Sentiment analysis is a tool that performs the computational study of identifying and extracting sentiment content of textual data that can be used to classify those public opinions posted on various topics in social media. In this paper, a sentiment polarity detection approach is presented, that detects the polarity of textual Facebook posts in Bangla containing people’s point of views on Bangladesh Cricket using three popular supervised machine learning algorithms named Naive Bayes (NB), support vector machines (SVM), and logistic regression (LR). Comparative result analysis is also provided between classifiers, where LR performed slightly better than SVM and NB by considering n-gram as a feature with an accuracy of 83% in the present world, we are not only the consumers of information but creators as well. The virtual world of social media, which is considered a free open forum for discussion; provides its participants a chance to shape or re-shape the digital information by expressing opinions. These opinions generally contain different types of sentiments. Sentiment analysis is a tool that performs the computational study of identifying and extracting sentiment content of textual data that can be used to classify those public opinions posted on various topics in social media. In this paper, a sentiment polarity detection approach is presented, that detects the polarity of textual Facebook posts in Bangla containing people’s point of views on Bangladesh Cricket using three popular supervised machine learning algorithms named Naive Bayes (NB), support vector machines (SVM), and logistic regression (LR). Comparative result analysis is also provided between classifiers, where LR performed slightly better than SVM and NB by considering n-gram as a feature with an accuracy of 83%.

Ascertaining polarity of public opinions on Bangladesh cricket using machine learning techniques

Faruque M. Abdullah,Rahman Saifur,Chakraborty Partha,Choudhury Tanupriya,Um Jung-Sup,Singh Thipendra Pal 대한공간정보학회 2022 Spatial Information Research Vol.30 No.1

In the present world, we are not only the consumers of information but creators as well. The virtual world of social media, which is considered a free open forum for discussion; provides its participants a chance to shape or re-shape the digital information by expressing opinions. These opinions generally contain different types of sentiments. Sentiment analysis is a tool that performs the computational study of identifying and extracting sentiment content of textual data that can be used to classify those public opinions posted on various topics in social media. In this paper, a sentiment polarity detection approach is presented, that detects the polarity of textual Facebook posts in Bangla containing people’s point of views on Bangladesh Cricket using three popular supervised machine learning algorithms named Naive Bayes (NB), support vector machines (SVM), and logistic regression (LR). Comparative result analysis is also provided between classifiers, where LR performed slightly better than SVM and NB by considering n-gram as a feature with an accuracy of 83%.

Circulating Gut-Homing (α₄β₇⁺) Plasmablast Responses against <i>Shigella</i> Surface Protein Antigens among Hospitalized Patients with Diarrhea

Sinha, Anuradha,Dey, Ayan,Saletti, Giulietta,Samanta, Pradip,Chakraborty, Partha Sarathi,Bhattacharya, M. K.,Ghosh, Santanu,Ramamurthy, T.,Kim, Jae-Ouk,Yang, Jae Seung,Kim, Dong Wook,Czerkinsky, Cecil American Society for Microbiology 2016 CLINICAL AND VACCINE IMMUNOLOGY Vol.23 No.7

<P>Developing countries are burdened with Shigella diarrhea. Understanding mucosal immune responses associated with natural Shigella infection is important to identify potential correlates of protection and, as such, to design effective vaccines. We performed a comparative analysis of circulating mucosal plasmablasts producing specific antibodies against highly conserved invasive plasmid antigens (IpaC, IpaD20, and IpaD120) and two recently identified surface protein antigens, pan-Shigella surface protein antigen 1 (PSSP1) and PSSP2, common to all virulent Shigella strains. We examined blood and stool specimens from 37 diarrheal patients admitted to the Infectious Diseases & Beliaghata General Hospital, Kolkata, India. The etiological agent of diarrhea was investigated in stool specimens by microbiological methods and real-time PCR. Gut-homing (alpha(4)beta(+)(7)) antibody secreting cells (ASCs) were isolated from patient blood by means of combined magnetic cell sorting and two-color enzymelinked immunosorbent spot (ELISPOT) assay. Overall, 57% (21 of 37) and 65% (24 of 37) of the patients were positive for Shigella infection by microbiological and real-time PCR assays, respectively. The frequency of alpha(4)beta(+)(7) IgG ASC responders against Ipas was higher than that observed against PSSP1 or PSSP2, regardless of the Shigella serotype isolated from these patients. Thus, alpha(4)beta(+)(7) ASC responses to Ipas may be considered an indirect marker of Shigella infection. The apparent weakness of ASC responses to PSSP1 is consistent with the lack of cross-protection induced by natural Shigella infection. The finding that ASC responses to IpaD develop in patients with recent-onset shigellosis indicates that such responses may not be protective or may wane too rapidly and/or be of insufficient magnitude.</P>