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Now showing items 1 - 16 of 83

  • Dynamics of solar wind speed: Cycle 23

    Sarkar, Tushnik   Khondekar, Mofazzal H.   Banerjee, Subrata  

    A statistical signal processing approach has been made to study the dynamics of the speed of steady flow of hot plasma from the corona of sun known as solar wind generated in Solar Cycle 23. A long time series of solar wind speed of length 2492 days from 1st Jan, 1997 to 28th October, 2003 collected from Coordinated Heliospheric Observations (COHO) data base at NASA's National Space Science Data Center (NSSDC) is investigated for this purpose. Detection of nonlinearity and chaos in dynamics of solar wind speed is the prime objective of this work. In the present analysis delay vector variance (DVV) method is used to detect the existence of nonlinearity within the dynamics of solar wind speed. To explore the signature of the chaos in it multiple statistical methodologies like '0-1' test, the correlation dimension analysis, computation of Information Entropy of the time series and Largest Lyapunov Exponent method have been applied. It has been observed that though the coronal plasma i.e. solar wind flow rate has a nonlinear dynamics but without any chaos. The absence of chaos indicates a probable regular behaviour of the series. The unit magnitude of the Correlation dimension indicates the presence of the deterministic component of the series. Embedding Dimension obtained argues that the deterministic component has dimension of six. The nearly zero value of the Lyapunov exponent claims that the system is conservative and exhibits Lyapunov stability. These revelations establish that not only the solar wind speed alone but the solar wind-magnetosphere coupling is also contributing towards the complexity of the magnetospheric plasma dynamics. (C) 2017 COSPAR. Published by Elsevier Ltd. All rights reserved.
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  • Study on chaos and bifurcation in DC-DC flyback converter

    Ghosh, Arnab   Banerjee, Subrata  

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  • Disseminated Histoplasmosis with Oral Manifestation in an Immunocompetent Patient

    Chatterjee, Debopriya   Chatterjee, Aishwarya   Agarwal, Manoj   Mathur, Meetu   Mathur, Setu   Mallikarjun, R.   Banerjee, Subrata  

    A case of disseminated histoplasmosis (DH) in a 60-year-old female patient is reported from Jaipur, Rajasthan, India. The patient presented with multiple papules on the skin surrounding the lips, face, torso, trunk, and back. She also complained of growth in the palate. Histoplasmosis was confirmed by biopsy and histopathology of skin and palatal lesions. This case report highlights the presenting features and occurrence of histoplasmosis in nonendemic region in India.
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    Systems and methods are provided for receiving at a provider edge routing device capabilities data representative of capabilities of computing devices disposed in a data center, the capabilities data having been published by an associated local data center edge device, and advertising, by the provider edge routing device, the capabilities data to other provider edge routing devices in communication with one another in a network of provider edge routing devices. The provider edge routing device also receives respective capabilities data from each of the other provider edge routing devices, wherein each of the other provider edge routing devices is associated with a respective local data center via a corresponding data center edge device, and stores all the capabilities data in a directory of capabilities. Thereafter, a request for computing services is received at the provider edge network and the methodology provides for selecting, based on the directory of capabilities, one of the data centers to fulfill the request for computing services to obtain a selected data center, and for routing the request for computing services to the selected data center.
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  • Solving OPF Problems using Biogeography Based and Grey Wolf Optimization Techniques

    Majumdar, Kingsuk   Das, Puja   Roy, Provas Kumar   Banerjee, Subrata  

    This paper presents biogeography-based optimization (BBO) and grey wolf Optimization(GWO) for solving the multi-constrained optimal power flow (OPF) problems in the power system. In this paper, the proposed algorithms have been tested in 9-bus system under various conditions along with IEEE 30 bus test system. A comparison of simulation results reveals optimization efficacy of the proposed scheme over evolutionary programming (EP), genetic algorithm (GA), mixed-integer particle swarm optimization (MIPSO) for the global optimization of multi-constraint OPF problems. It is observed that GWO is far better in comparison to other listed optimization techniques and can be used for aforesaid problems with high efficiency.
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  • An Improved Interleaved Boost Converter With PSO-Based Optimal Type-III Controller

    Banerjee, Subrata   Ghosh, Arnab   Rana, Niraj  

    This paper presents an improved interleaved boost converter (IBC) with optimal Type-III controller by utilizing voltage mode control. Due to the presence of several power switches in parallel path, the degree of freedom has been increased in IBC. Also, the IBC produces lower output voltage ripples, so the size and losses of the output filter can significantly be reduced compared with conventional BC. But due to the nonminimum phase problem of IBC, closed-loop bandwidth is restricted that causes slower converter dynamics. It is difficult for the conventional proportional-integral-differential controller to exhibit good performance with line, load changes, and parametric uncertainty. So an optimal Type-III controller is designed and implemented for achieving better closed-loop dynamic performance and stability. Initially, controller parameters have been designed by using the classical "k-factor" method, and then particle swarm optimization-based optimal Type-III controller is developed for the proposed IBC. The comparative closedloop performances of BC and IBC with classical and optimal Type-III controllers have been presented. The proposed control scheme by utilizing the optimized Type-III controller in IBC is newly introduced in this paper and has not been reported earlier. The overall control circuit diagram using voltage-mode controlled two-phase IBC has been implemented by simple analog control circuit and the cost of complete experimental setup is very cheap. Simulation and experimental results have been produced to show the efficacy of the proposed converter control system.
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  • Load frequency control of interconnected power system using grey wolf optimization

    Guha, Dipayan   Roy, Provas Kumar   Banerjee, Subrata  

    In this article an attempt has been made to solve load frequency control (LFC) problem in an interconnected power system network equipped with classical PI/PID controller using grey wolf optimization (GWO) technique. Initially, proposed algorithm is used for two-area interconnected non-reheat thermal thermal power system and then the study is extended to three other realistic power systems, viz. (i) two area multi-units hydro-thermal, (ii) two-area multi-sources power system having thermal, hydro and gas power plants and (iii) three-unequal-area all thermal power system for better validation of the effectiveness of proposed algorithm. The generation rate constraint (GRC) of the steam turbine is included in the system modeling and dynamic stability of aforesaid systems is investigated in the presence of GRC. The controller gains are optimized by using GWO algorithm employing integral time multiplied absolute error (ITAE) based fitness function. Performance of the proposed GWO algorithm has been compared with comprehensive learning particle swarm optimization (CLPSO), ensemble of mutation and crossover strategies and parameters in differential evolution (EPSDE) and other similar meta-heuristic optimization techniques available in literature for similar test system. Moreover, to demonstrate the robustness of proposed GWO algorithm, sensitivity analysis is performed by varying the operating loading conditions and system parameters in the range of 50%. Simulation results show that GWO has better tuning capability than CLPSO, EPSDE and other similar population-based optimization techniques. (C) 2015 Elsevier B.V. All rights reserved.
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  • An Improved Interleaved Boost Converter with PSO Based Optimal Type-III Controller

    Banerjee, Subrata   Ghosh, Arnab   Rana, Niraj  

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  • Impact of an Oncology Palliative Care Clinic on Access to Home Care Services

    Jang, Raymond W.   Burman, Debika   Swami, Nadia   Kotler, Jennifer   Banerjee, Subrata   Ridley, Julia   Mak, Ernie   Bryson, John   Rodin, Gary   Le, Lisa W.   Zimmermann, Camilla  

    Home care (HC) is important for patients with cancer as performance status declines. Our study of 1224 patients at a Canadian cancer center examined the impact of an oncology palliative care clinic (OPCC) on HC referral. The HC referral frequency was calculated before and after the first OPCC consultation, in total and according to performance status (Palliative Performance Scale, PPS). Characteristics associated with HC referral were investigated. After the first OPCC consultation, there was an increase in HC referral from 39% (477 of 1224; 49% of those with PPS 60) to 69% (841 of 1224; 88% of those with PPS 60). Factors independently associated with HC referral were poor PPS (P < .001) and older age (P = .003). Thus OPCC involvement resulted in markedly increased HC referrals, particularly for older patients with poor performance status.
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  • Simple prognostic model for patients with advanced cancer based on performance status.

    Jang, Raymond W   Caraiscos, Valerie B   Swami, Nadia   Banerjee, Subrata   Mak, Ernie   Kaya, Ebru   Rodin, Gary   Bryson, John   Ridley, Julia Z   Le, Lisa W   Zimmermann, Camilla  

    PURPOSE: Providing survival estimates is important for decision making in oncology care. The purpose of this study was to provide survival estimates for outpatients with advanced cancer, using the Eastern Cooperative Oncology Group (ECOG), Palliative Performance Scale (PPS), and Karnofsky Performance Status (KPS) scales, and to compare their ability to predict survival.; METHODS: ECOG, PPS, and KPS were completed by physicians for each new patient attending the Princess Margaret Cancer Centre outpatient Oncology Palliative Care Clinic (OPCC) from April 2007 to February 2010. Survival analysis was performed using the Kaplan-Meier method. The log-rank test for trend was employed to test for differences in survival curves for each level of performance status (PS), and the concordance index (C-statistic) was used to test the predictive discriminatory ability of each PS measure.; RESULTS: Measures were completed for 1,655 patients. PS delineated survival well for all three scales according to the log-rank test for trend (P < .001). Survival was approximately halved for each worsening performance level. Median survival times, in days, for each ECOG level were: EGOG 0, 293; ECOG 1, 197; ECOG 2, 104; ECOG 3, 55; and ECOG 4, 25.5. Median survival times, in days, for PPS (and KPS) were: PPS/KPS 80-100, 221 (215); PPS/KPS 60 to 70, 115 (119); PPS/KPS 40 to 50, 51 (49); PPS/KPS 10 to 30, 22 (29). The C-statistic was similar for all three scales and ranged from 0.63 to 0.64.; CONCLUSION: We present a simple tool that uses PS alone to prognosticate in advanced cancer, and has similar discriminatory ability to more complex models. Copyright =C2=A9 2014 by American Society of Clinical Oncology.
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  • DNA binding domain of RFX5: Interactions with X-box DNA and RFXANK

    Chakraborty, Madhumita   Sengupta, Amitava   Bhattacharya, Dipankar   Banerjee, Subrata   Chakrabarti, Abhijit  

    Regulatory factor X (RFX) is a heterotrimeric protein complex having RFX5, RFXANK and RFXAP as its three subunits. It is involved in the regulation of the transcription of MHCII molecules in antigen presenting cells. The RFX complex binds to X-box DNA, using the DNA binding domain, present in RFX5. The DNA binding domain (DBD) of RFX5 (12 kD) and intact RFXANK (35 kD) were subcloned, expressed and purified. The associations of RFX5DBD with the X-box DNA and between RFX5DBD and RFXANK were measured in this study. The interaction of RFX5DBD and X-box DNA was studied using steady state fluorescence quenching and circular dichroism. The binding dissociation constant (K(d)) of the DNA-protein complex was determined from fluorescence measurements. The van't Hoff plot was linear over the temperature range 10-25 degrees C and the binding was found to be entropy-driven and enthalpy-favorable. The effect of electrolytes in RFX5DBD-DNA association was also studied. Molecular association between RFX5DBD and RFXANK has been observed by fluorescence resonance energy transfer (FRET) measurements, changes in the ratio of the two vibronic intensities of pyrene labeled RFX5DBD in presence of RFXANK and chemical cross-linking followed by tandem mass spectrometry. Results showed that the two proteins could interact in the absence of the third subunit RFXAP, in vitro with an apparent dissociation constant (K(d)) of 128 nM. (C) 2010 Elsevier B.V. All rights reserved.
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  • A Review Note on Different Components of Simple Electromagnetic Levitation Systems

    Banerjee, Subrata   Sarkar, MrinalKanti   Biswas, PabitraKumar   Bhaduri, Rupam   Sarkar, Prasanta  

    Electromagnetic levitation is an important area of research. There is lot of applications of maglev in industry. Extensive research is going on for the last two decades throughout the world to design the latest form of the maglev system. Due to interdisciplinary nature, many aspects are still open in maglev research. The major components in an electromagnetic suspension system are (i) actuator, (ii) sensor, (iii) controller, and (iv) power amplifier. For the successful implementation for any maglev-based project, the basic knowledge of these components is necessary. In this manuscript, an extensive review of different components of electromagnetic levitation systems has been presented.
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  • Interconversion of three measures of performance status: An empirical analysis

    Ma, Clement   Bandukwala, Shazeen   Burman, Debika   Bryson, John   Seccareccia, Dori   Banerjee, Subrata   Myers, Jeff   Rodin, Gary   Dudgeon, Deborah   Zimmermann, Camilla  

    Purpose: To construct empirically a conversion table to convert performance status scores among the Eastern Cooperative Oncology Group (ECOG), Karnofsky Performance Status (KPS) and Palliative Performance Scale (PPS) measures, using a large sample of patients with advanced cancer. Methods: Seven physicians completed assessments on 1385 consecutive patients attending an oncology palliative care clinic, or admitted to an acute cancer palliative care unit. The three measures were distributed as a questionnaire package; the order in which they were presented was randomly assigned for each week. Scales were compared using the hit rate and the weighted kappa coefficient (kappa(w)) The KPS and PPS were compared directly; for comparisons of either scale with the ECOG, all 70 possible categorisations of KPS and PPS were computed. An 'ideal' categorisation was selected based on maximisation of both statistical methods. Results: The KPS and PPS matched in 1209 out of 1385 assessments (hit rate 87%; kappa(w) 0.97). For both the KPS and the PPS, the categorisation of 100 (ECOG 0), 80-90 (1), 60-70(2), 40-50(3), 10-30 (4) had the highest hit rate (75%), and the second highest kappa(w) (0.84, p < 0.0001). One other combination had a slightly higher kappa(w) (0.85 for both KPS and PPS), but a lower hit rate (73% for KPS, 72% for PPS). Conclusions: We have derived empirically a conversion scale among the ECOG, KPS and PPS scales. The proposed scale provides a means of translating amongst these measures, which may improve accuracy of communication about performance status amongst oncology clinicians and researchers. (C) 2010 Elsevier Ltd. All rights reserved.
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  • System and Method for Obtaining Simultaneous Levitation and Rotation of a Ferromagnetic Object

    Banerjee, Subrata   Sarkar, Mrinal Kanti   Ghosh, Arnab  

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  • A Novel Interleaved Tri-State Boost Converter With Lower Ripple and Improved Dynamic Response

    Rana, Niraj   Kumar, Mukesh   Ghosh, Arnab   Banerjee, Subrata  

    In this paper, the design and development of a novel interleaved tri-state boost converter (ITBC), which produces lower ripple and exhibits better dynamic response, is discussed. Boost converters are frequently connected in parallel and operate in an interleaving mode for the reduction of ripple content in source current and in output voltage. In this way, interleaved boost converter (IBC) is conceived, which improves the power handling capabilities and increases the overall system rating. It also has the advantage of reduction of the ripple content in source current and output voltage, but when control-to-output transfer function of IBC is derived under continuous conduction mode of operation, then a right-half-plane (RHP) zero appears in the transfer function. Due to the presence of RHP zero, IBC has nonminimum phase problem, which deteriorates the dynamic performance. The tri-state boost converter (TBC) is the best choice for RHP zero elimination, but due to the extra freewheeling mode, ripple content will also be increased. The proposed converter is a parallel combination of two TBC and operates in an interleaving mode. Therefore, the proposed converter has both of the advantages of TBC and IBC. The performance analyses of ITBC, TBC, and IBC have been studied based on simulation and experimental results. From the comparative analysis, it is observed that ITBC is performed better than other two converters. The ripple comparisons between three converters have also been done. It is found that the ripple content in ITBC is slightly greater than IBC but is less than TBC.
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  • Some aspects of switching power amplifier used in electromagnetic levitation system

    Banerjee, Subrata   Bhaduri, Rupam   Prasad, Dinkar  

    Power amplifier is one of the important elements of any attraction type levitation system. Due to the advancement in power electronics and control technology it is now possible to develop power amplifier which will have the properties like fast dynamics, large bandwidth, ability to carry large payload, energy efficient, high reliability and cost effective. Both linear and switching mode power amplifiers have been used in the field of DC electromagnetic suspension system. In this paper different possible switched mode power circuits for both single as well as multi-magnet based electromagnetic levitation system have been discussed and a comparative study has been made of the different topologies of power amplifiers based on their structure, working principle and experimental results. In the actual work design, fabrication and testing of both single and multi-magnet based electromagnetic levitation scheme has been made as a complete project. But in this paper the main focus is on the power amplifier.
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