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A new protocol for concurrently allocating licensed spectrum to underlay cognitive users

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Digital Communications and Networks 2018年第3期4卷 200-208页

作者： Sabyasachi chatterjee Prabir Banerjee Mita Nasipuri Department of Electronics and Communication Engineering Heritage Institute of Technology Kolkata India Department of Computer Science Engineering Jadavpur university Kolkata India

Cognitive radio technology makes efficient use of the valuable radio frequency spectrum in a non-interfering manner to solve the problem of spectrum scarcity. This paper aims to design a scheme for the concurrent use of licensed frequencies by Underlay Cognitive Users （UCUs）. We develop a new receiver-initiated Medium Access Control （MAC） protocol to facilitate the selections of alternative reliable carrier frequencies. A circuit is designed to establish reliable carrier selections based on the Received Signal Strength Indicator （RSSI） at the receiving end. Based on both packet-level simulations and various performance parameters, a comparison is carried out among conventional techniques, including the Multiple Access with Collision Avoidance （MACA） and MACA by invitation（MACA-BI） techniques, and our scheme. The simulated results demonstrate that when conventional techniques are used, the system overhead time increases from 0.5 s on the first attempt to 16.5 s on the sixth attempt. In the proposed scheme under the same failure condition, overhead time varies from 0.5 s to 2 s. This improvement is due to the complete elimination of the exponential waiting time that occurs during failed transmissions. An average efficiency of 60% is achieved with our scheme while only 43% and 34% average efficiencies are achieved with the MACA and MACA-BI techniques, respectively. The throughput performance of our scheme on the fourth attempt is 7 Mbps, whereas for the MACA and MACA-BI protocols, it is 1.9 Mbps and 2.2 Mbps respectively.

关键词： Exponential back-off time Interference temperature limit Medium-access control protocol Received signal strength indicator Underlay cognitive user

Suspended sediment yield modeling in Mahanadi River, India by multi-objective optimization hybridizing artificial intelligence algorithms

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International Journal of Sediment Research 2021年第1期36卷 76-91页

作者： Arvind Yadav Snehamoy chatterjee Sk Md Equeenuddin Department of Electronics and Computer Engineering Koneru Lakshmaiah Education Foundation Department of Mining Engineering National Institute of Technology Department of Geological and Mining Engineering and Sciences Michigan Technological University Department of Earth & Atmospheric Sciences National Institute of Technology

River sediment produced through weathering is one of the principal landscape modification processes on *** are an integral part of the hydrologic cycle and are the major geologic agents that erode the continents and transport water and sediments to the *** of suspended sediment yield is always a key parameter for planning and management of any river *** is always challenging to model sediment yield using traditional mathematical models because they are incapable of handling the complex non-linearity and *** suspended sediment modeling of the river depends on the number of factors such as rock type,relief,rainfall,temperature,water discharge and catchment *** this study,we proposed a hybrid genetic algorithm-based multi-objective optimization with artificial neural network(GA-MOO-ANN) with automated parameter tuning model using these factors to estimate the suspended sediment yield in the entire Mahanadi River *** model was validated by comparing statistically with other models,and it appeared that the GA-MOO-ANN model has the lowest root mean squared error(0.009) and highest coefficient of correlation(0.885) values among all comparative models(traditional neural network,multiple linear regression,and sediment rating curve) for all *** was also observed that the proposed model is the least biased(0.001) ***,the proposed GA-MOOANN is the most capable model,compared to other studied models,for estimating the suspended sediment yield in the entire Mahanadi river basin,*** results also suggested that the proposed GA-MOO-ANN model is unable to estimate suspended sediment yield satisfactorily at gauge stations having very small catchment areas whereas performing satisfactorily on locations having moderate to the large catchment *** models provide the best result at Tikarapara,the gauge station location in the extreme downstream,having the largest catchment area.

关键词： Artificial neural network Genetic algorithm Multi-objective genetic algorithm Suspended sediment yield Mahanadi river

Inference on disk-jet connection of MAXI J1836–194 from spectral analysis with the TCAF solution

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Research in Astronomy and Astrophysics 2020年第3期20卷 28-41页

作者： Arghajit Jana Dipak Debnath Sandip KChakrabarti Debjit chatterjee Indian Centre for Space Physics 43 ChalantikaGaria St.Rd.Kolkata700084India

Galactic transient black hole candidate(BHC)MAXI J1836–194 was discovered on 2011 Aug30,by MAXI/GSC and Swift/*** source activity during this outburst continued for^3 months before entering into the quiescent *** again became active in March 2012 and continued for another^2 *** this paper,3-25 keV RXTE/PCA spectra from the 2011 outburst and 0.5-10.0 keV Swift/XRT data during its 2012 outburst are analyzed with the two-component advective flow(TCAF)model based fits files in *** calculate the X-ray contributions coming from jets/outflow using a newly developed method based on the deviation of the TCAF model *** also study the correlation between observed radio and estimated jet X-ray *** correlation indices(b)are found to be 1.79 and 0.61,when the 7.45 GHz Very Large Array(VLA)radio flux is correlated with the total X-ray and jet X-ray fluxes in 3-25 keV range *** has been found that the jet contributes in X-rays up to a maximum of 86%during its 2011 *** makes the BHC MAXI J1836–194 strongly jet dominated during the initial rising phase.

关键词： X-Rays:binaries stars individual:(MAXI J1836–194) stars:black holes accretion,accretion disks ISM:jets and outflows radiation:dynamics

Organic farming in India: a vision towards a healthy nation

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Food Quality and Safety 2020年第2期4卷 69-76页

作者： Suryatapa Das Annalakshmi chatterjee Tapan Kumar Pal Department of Food and Nutrition Maharani Kasiswari CollegeUniversity of CalcuttaKolkataIndia Department of Home Science University of CalcuttaKolkataIndia Department of Biotechnology Bengal Institute of TechnologyKolkataIndia

Food quality and safety are the two important factors that have gained ever-increasing attention in general *** grown foods have immense adverse health effects due to the presence of higher pesticide residue,more nitrate,heavy metals,hormones,antibiotic residue,and also genetically modified ***,conventionally grown foods are less nutritious and contain lesser amounts of protective *** the quest for safer food,the demand for organically grown foods has increased during the last decades due to their probable health benefits and food safety *** food production is defined as cultivation without the application of chemical fertilizers and synthetic pesticides or genetically modified organisms,growth hormones,and *** popularity of organically grown foods is increasing day by day owing to their nutritional and health *** farming also protects the environment and has a greater socio-economic impact on a *** is a country that is bestowed with indigenous skills and potentiality for growth in organic *** India was far behind in the adoption of organic farming due to several reasons,presently it has achieved rapid growth in organic agriculture and now becomes one of the largest organic producers in the ***,organic farming has a great impact on the health of a nation like India by ensuring sustainable development.

关键词： food safety organic food biodiversity sustainable farming conventional farming

Numerical analysis of non-isothermal viscous jet with peripheral heat transfer

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International Journal of Modeling, Simulation, and Scientific Computing 2016年第3期7卷 50-73页

作者： Sulagna chatterjee Trisha Sen Anindya Mitra Department of Chemical Engineering Heritage Institute of Technology Kolkata 700107India Department of Chemical Engineering IIT Bombay Mumbai 400076India Department of Chemical Engineering University of Waterloo ON N2L 3G1 Canada

A fluid jet ejected from micron size nozzle is a commonly occurring phenomenon in biomedical engineering,printing technology and micro-fluidic *** of a jet into drops occurs due to disturbances induced by external *** work explores the various sources of perturbation and their effect on jet disintegration through numerical simulation of a two-dimensional non-isothermal *** mathematical approach uses a novel technique to combine analytical solutions for the energy balance equation in the radial direction to solve the complete two dimensional *** two dimensional energy balance equation is simultaneously solved together with the axi-symmetric Navier–Stokes equations using the slender-jet approximation to predict jet *** energy balance takes into account of peripheral heat transfer to the environment through analytical expressions derived from radial *** model helps in understanding the factors in dynamic temperature variations that eventually render the jet *** distinguishing aspect of this work is the analysis of the effect of a periodic thermal perturbation applied at any point in the domain of a progressive jet,a situation typically encountered in thermal inkjet printers and not considered *** presented for non-isothermal jets which are both stationary and moving illustrate the effect of jet velocity in propagation of perturbation and subsequent drop *** major contribution of this numerical study is that it provides an insight on novel ways of controlling droplet formation in bubble jet *** study demonstrates that thermal disturbance propagating from periodic heating can be manipulated to shape the droplets and control their breakage point along the jet.

关键词： Nonlinear viscous microjets Bessel functions heat transfer Navier-Stokes slender jet approximation

Magnetic Phase Separation in Diluted Magnetic System:Zn1-xFexO

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Acta Metallurgica Sinica(English Letters) 2017年第6期30卷 521-527页

作者： Archita Mondal Sanchari Sarkar Neepamala Giri Souvik chatterjee Ruma Ray Department of Physics Jadavpur UniversityKolkata 700 032India UGC-DAE Consortium for Scientific Research Kolkata CentreSector IIILB-8Salt LakeKolkata 700098India

Single-phase diluted magnetic systems Zn1-xFexO have been prepared by chemical route. Structural and spectroscopic （UV-Vis and Mossbauer） studies indicate the incorporation of Fe^3＋ ions in the lattice sites. The UV-Vis results point to a systematic increase in the band gap with increasing Fe doping. The room temperature magnetization of Zni-xFexO indicates a paramagnetic behavior which is in accordance with the Mossbauer results, illustrating quadrupolar doublet. At low temperature, the zero-field-cooled （ZFC） magnetization shows a cusp and this temperature increases systematically with decreasing particle size. The weak exchange bias effect manifested by a M-H loop shift is observed for x = 0.03. This shift is accompanied by the enhancement of coercivity. The dc magnetization results suggest the coexis tence of ferromagnetic and antiferromagnetic exchange interactions for low doping of Fe, i.e., for x = 0.03.

关键词： Diluted magnetic system Optical band gap Moissbauer Exchange bias effect

Studies on the effects of moisture and ageing on charge de-trapping properties of oilimpregnated pressboard based on IRC measurement

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High Voltage 2019年第2期4卷 151-157页

作者： Nasirul Haque Sovan Dalai Biswendu chatterjee Sivaji Chakravorti Department of Electrical Engineering Jadavpur UniversityRaja S.C.Mullick RoadKolkataWest BengalIndia NIT Calicut CalicutKeralaIndia

The dielectric properties of oil-paper insulation degrade due to moisture ingression and *** degradation significantly impacts the space charge accumulation and charge trapping behaviour in the insulation,which are vital parameters for insulation health under the high-voltage direct current *** this work,an improved model based on the isothermal relaxation current(IRC)has been developed to study the charge trapping behaviour of an oil pressboard under the influence of moisture and *** conventional IRC model considers the total relaxation current because of charge de-trapping ***,in the case of a composite dielectric like oil pressboard,dipolar relaxation also affects the relaxation *** this work,a methodology has been proposed to investigate charge de-trapping behaviour of oil-pressboard insulation considering the dipole relaxation process from IRC *** this purpose,frequency domain spectroscopy measurements and IRC measurements have been performed on oil-impregnated pressboard specimens carefully prepared in the laboratory having different ageing conditions and moisture *** presented in this work depict that charge trapping parameters,*** trap depth and trapped charge distribution are highly affected both by ageing and *** was observed that ageing leads to the generation of deeper traps,while moisture mainly enhances the density of shallow traps.

关键词： moisture trapping charge

Contactins in the central nervous system: role in health and disease

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Neural Regeneration Research 2019年第2期14卷 206-216页

作者： Madhurima chatterjee Detlev Schild Charlotte E.Teunissen Amsterdam UMC VU University Medical Center Department of Clinical Chemistry Amsterdam Neuroscience Institute of Neurophysiology and Cellular Biophysics University of G?ttingen DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) University of G?ttingen DFG Excellence Cluster 171 University of G?ttingen

Contactins are a group of cell adhesion molecules that are mainly expressed in the brain and play pivotal roles in the organization of axonal domains, axonal guidance, neuritogenesis, neuronal development, synapse formation and plasticity, axo-glia interactions and neural regeneration. Contactins comprise a family of six members. Their absence leads to malformed axons and impaired nerve conduction. Contactin mediated protein complex formation is critical for the organization of the axon in early central nervous system development. Mutations and differential expression of contactins have been identified in neuro-developmental or neurological disorders. Taken together, contactins are extensively studied in the context of nervous system development. This review summarizes the physiological roles of all six members of the Contactin family in neurodevelopment as well as their involvement in neurological/neurodevelopmental disorders.

关键词： cell adhesion molecule Contactins axonal domain,neurogenesis synaptogenesis autism spectrum disorder neuro-developmental disorder neurological disease

Carbon Dioxide and Nitrous Oxide Emissions from Naturally Occurring Sulfate-Based Saline Soils at Different Moisture Contents

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Pedosphere 2017年第5期27卷 868-876页

作者： Resham THAPA Amitava chatterjee Abbey WICK Kirsten BUTCHER Department of Soil Sciences School of Natural Resources Management North Dakota State University

Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.

关键词： electric conductivity C and N mineralization salinity sulfate salts soil salinization soil water-filled pore space