Amitava Biswas - Academia.edu (original) (raw)

Papers by Amitava Biswas

Global Spine Journal, 2019

Study Design: Prospective matched cohort study Objective: To evaluate the sensitivity and specifi... more Study Design: Prospective matched cohort study Objective: To evaluate the sensitivity and specificity of Gene Xpert in the diagnosis of spinal tuberculosis. Methods: From January 2016 to August 2018, Gene Xpert results were prospectively studied in 68 patients of clinicoradiologically suspected spinal tuberculosis (STB) and a control group (CG) of 92 patients, all of whom underwent computed tomography–guided/C-arm-guided/open surgical biopsy. Sensitivity, specificity, positive predictive value, and negative predictive value are obtained using standard equations. Results: Out of 68 cases of STB, Gene Xpert was positive in 62 (true positive: 62/68) and negative in 6 (false negative: 6/68). Gene Xpert was negative for all 92 cases of CG (true negative: 92/92, false positive 0/92). Thus, in our series, sensitivity of Gene Xpert is 91.18%, specificity is 100%, positive predictive value is 100%, and negative predictive value is 93.88%. Out of all cases of STB, 62/68 (91.18%) were Gene Xpe...

Global Spine Journal, 2015

Introduction MRI plays an important role in the diagnosis of spinal tuberculosis with a high spec... more Introduction MRI plays an important role in the diagnosis of spinal tuberculosis with a high specificity and sensitivity. The role of MRI in predicting the healed status of caries spine to establish an end point of treatment is still not clear. In this study, we have proposed few MRI parameters of healed spinal tuberculosis and have attempted to formulate a scoring system to document healing. To find out the reliability of the proposed MRI parameters, we have statistically tested the scores given by three independent observers and assessed the interobserver reliability of the parameters. Material and Methods It is a prospective observational study. A total of 20 patients of spinal tuberculosis diagnosed clinico-radiologically and histopathologically after 1 year of ATD were enrolled. Patients younger than 20 years, with multifocal lesions, erratic tubercular treatment, and relapse and immunocompromised states were excluded. The pre and 1-year posttreatment MRIs were collected and a ...

Searching for textual information has become an important activity on the web. To satisfy the ris... more Searching for textual information has become an important activity on the web. To satisfy the rising demand and user expectations, search systems should be fast, scalable and deliver relevant results. To decide which objects should be retrieved, search systems should compare holistic meanings of queries and text document objects, as perceived by humans. Existing techniques do not enable correct comparison of composite holistic meanings like: “evidences on role of DR2 gene in development of diabetes in Caucasian population”, which is composed of multiple elementary meanings: “evidence”, “DR2 gene”, etc. Thus these techniques can not discern objects that have a common set of keywords but convey different meanings. Hence we need new methods to compare composite meanings for superior search quality. In distributed search engines, for scalability, speed and efficiency, index entries should be systematically distributed across multiple index-server nodes based on the meaning of the object...

Models, Methodologies and Applications

2011 IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum, 2011

Superior and fast semantic comparison improves the quality of web-search. Semantic comparison inv... more Superior and fast semantic comparison improves the quality of web-search. Semantic comparison involves dot product computation of large sparse tensors which is time consuming and expensive. In this paper we present a low power parallel architecture that consumes only 15.41 Watts and demonstrates a speed-up in the order of 10 5 compared to a contemporary hardware design, and in the order of 10 4 compared to a purely software approach. Such high performance low power architecture can be used in semantic routers to elegantly implement energy efficient distributed search engines.

2012 Annual IEEE India Conference (INDICON), 2012

This research paper interacts with a new method for reduction of model with higher order continuo... more This research paper interacts with a new method for reduction of model with higher order continuous time approach into lower order continuous time model. Reduction of the model is done with improvement using hybrid function Approximation method. By this method, the obtained low order model retains properties of the higher order system like stability and it reduces computational time also. This proposed method demonstrated with the model of numerical example considered.

Applied Mathematics and Computation, 2012

The present work proposes a new set of orthogonal hybrid functions (HF) which evolved from synthe... more The present work proposes a new set of orthogonal hybrid functions (HF) which evolved from synthesis of orthogonal sample-and-hold functions (SHF) and triangular functions (TF). The HF set is used to approximate a time function in a piecewise linear manner. For such approximation, the mean integral square error (MISE) is much less than block pulse function based approximation which always provides staircase solutions and it is found that HF based approximation is a strong contender of approximations based upon orthogonal polynomials like Legendre polynomials. The respective MISE's and elapsed times for MISE computations for these three kinds of approximations are also studied in detail. The one-shot operational matrices for integration of different orders in HF domain are also derived. These matrices are employed for more accurate multiple integration. An example is treated to determine efficiency of these matrices. Finally, these matrices are employed for solving third order non-homogeneous differential equations followed by a numerical example. The results, obtained via MATLAB, are compared with the exact solution as well as the results obtained via 4th order Runge-Kutta method.

Global Spine Journal, 2019

Study Design: Prospective matched cohort study Objective: To evaluate the sensitivity and specifi... more Study Design: Prospective matched cohort study Objective: To evaluate the sensitivity and specificity of Gene Xpert in the diagnosis of spinal tuberculosis. Methods: From January 2016 to August 2018, Gene Xpert results were prospectively studied in 68 patients of clinicoradiologically suspected spinal tuberculosis (STB) and a control group (CG) of 92 patients, all of whom underwent computed tomography–guided/C-arm-guided/open surgical biopsy. Sensitivity, specificity, positive predictive value, and negative predictive value are obtained using standard equations. Results: Out of 68 cases of STB, Gene Xpert was positive in 62 (true positive: 62/68) and negative in 6 (false negative: 6/68). Gene Xpert was negative for all 92 cases of CG (true negative: 92/92, false positive 0/92). Thus, in our series, sensitivity of Gene Xpert is 91.18%, specificity is 100%, positive predictive value is 100%, and negative predictive value is 93.88%. Out of all cases of STB, 62/68 (91.18%) were Gene Xpe...

Global Spine Journal, 2015

Introduction MRI plays an important role in the diagnosis of spinal tuberculosis with a high spec... more Introduction MRI plays an important role in the diagnosis of spinal tuberculosis with a high specificity and sensitivity. The role of MRI in predicting the healed status of caries spine to establish an end point of treatment is still not clear. In this study, we have proposed few MRI parameters of healed spinal tuberculosis and have attempted to formulate a scoring system to document healing. To find out the reliability of the proposed MRI parameters, we have statistically tested the scores given by three independent observers and assessed the interobserver reliability of the parameters. Material and Methods It is a prospective observational study. A total of 20 patients of spinal tuberculosis diagnosed clinico-radiologically and histopathologically after 1 year of ATD were enrolled. Patients younger than 20 years, with multifocal lesions, erratic tubercular treatment, and relapse and immunocompromised states were excluded. The pre and 1-year posttreatment MRIs were collected and a ...

Searching for textual information has become an important activity on the web. To satisfy the ris... more Searching for textual information has become an important activity on the web. To satisfy the rising demand and user expectations, search systems should be fast, scalable and deliver relevant results. To decide which objects should be retrieved, search systems should compare holistic meanings of queries and text document objects, as perceived by humans. Existing techniques do not enable correct comparison of composite holistic meanings like: “evidences on role of DR2 gene in development of diabetes in Caucasian population”, which is composed of multiple elementary meanings: “evidence”, “DR2 gene”, etc. Thus these techniques can not discern objects that have a common set of keywords but convey different meanings. Hence we need new methods to compare composite meanings for superior search quality. In distributed search engines, for scalability, speed and efficiency, index entries should be systematically distributed across multiple index-server nodes based on the meaning of the object...

Models, Methodologies and Applications

2011 IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum, 2011

Superior and fast semantic comparison improves the quality of web-search. Semantic comparison inv... more Superior and fast semantic comparison improves the quality of web-search. Semantic comparison involves dot product computation of large sparse tensors which is time consuming and expensive. In this paper we present a low power parallel architecture that consumes only 15.41 Watts and demonstrates a speed-up in the order of 10 5 compared to a contemporary hardware design, and in the order of 10 4 compared to a purely software approach. Such high performance low power architecture can be used in semantic routers to elegantly implement energy efficient distributed search engines.

2012 Annual IEEE India Conference (INDICON), 2012

This research paper interacts with a new method for reduction of model with higher order continuo... more This research paper interacts with a new method for reduction of model with higher order continuous time approach into lower order continuous time model. Reduction of the model is done with improvement using hybrid function Approximation method. By this method, the obtained low order model retains properties of the higher order system like stability and it reduces computational time also. This proposed method demonstrated with the model of numerical example considered.

Applied Mathematics and Computation, 2012

The present work proposes a new set of orthogonal hybrid functions (HF) which evolved from synthe... more The present work proposes a new set of orthogonal hybrid functions (HF) which evolved from synthesis of orthogonal sample-and-hold functions (SHF) and triangular functions (TF). The HF set is used to approximate a time function in a piecewise linear manner. For such approximation, the mean integral square error (MISE) is much less than block pulse function based approximation which always provides staircase solutions and it is found that HF based approximation is a strong contender of approximations based upon orthogonal polynomials like Legendre polynomials. The respective MISE's and elapsed times for MISE computations for these three kinds of approximations are also studied in detail. The one-shot operational matrices for integration of different orders in HF domain are also derived. These matrices are employed for more accurate multiple integration. An example is treated to determine efficiency of these matrices. Finally, these matrices are employed for solving third order non-homogeneous differential equations followed by a numerical example. The results, obtained via MATLAB, are compared with the exact solution as well as the results obtained via 4th order Runge-Kutta method.