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Chaos to order： Effect of random predation in a Holling type IV tri-trophic food chain system with closure terms

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International Journal of Biomathematics 2016年第5期9卷 153-170页

作者： Partha ghosh Pritha Dast Debasis Mukherjee Department of Mathematics Indian Institute of Engineering Science and Technology Shibpur Howrah 711103 India Department of Mathematics Vivekananda College Thakurpukur Kolkata 700063 India

Complex dynamics of modified Hastings-Powell （HP） model （phytoplankton-zoo- plankton-fish） with Holling type IV functional response and density-dependent morta- lity （closure terms） for top predator species is investigated in this paper. Closure terms describe the mortality of top predator in plankton food chain models. Modified HP model with Holling type IV functional response gives rise to similar type of chaotic dynamics （inverted ＂teacup attractor＂） as observed in original HP model with Holling type II functional response. It is observed that introduction of nonlinear closure terms eliminate chaos and system dynamics becomes stable. Observation of this paper support the ＂Steele-Henderson conjecture＂ that, nonlinear closure terms eliminate or reduces limit cycles and chaos in plankton food chain models. Chaotic or stable dynamics are numerically verified by Lyapunov exponents （LE） method and Sil＇nikov eigenvalue anal- ysis and also illustrated graphically by plotting bifurcation diagrams. It is assumed that mortality of fish population, caused by higher-order predators （which are not explicitly included in the model） is not constant, rather it exhibits random variation through- out the year. To incorporate the effect of random mortality of fish population, white noise term is introduced into the original deterministic model. It is observed that the corresponding stochastic model is stable in mean square when the intensity of noise is small. Keywords： Holling type IV; chaos; closure term; white noise; mean square stability

关键词：随机变化 HollingⅡ型功能性反应食物链系统封闭捕食效应 Lyapunov指数食物链模型均方稳定性

Improvement on the Multihop Shareholder Discovery for Threshold Secret Sharing in MANETs

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Journal of Computer Science & Technology 2011年第4期26卷 711-721页

作者： Seleviawati Tarmizi Prakash Veeraraghavan Somnath ghosh Department of Computer Science and Computer Engineering La Trobe University

The collaboration of at least a threshold number of secret shareholders in a threshold secret sharing scheme is a strict requirement to ensure its intended functionality. Due to its promising characteristics, such a scheme has been proposed to solve a range of security problems in mobile ad hoc networks. However, discovering a sufficient number of secret shareholders in such dynamic and unpredictable networks is not easy. In this paper, we propose a more efficient shareholder discovery mechanism compared to our previous work. The discovery process is performed in a multihop fashion to adapt to the mobile ad hoc network environment. We introduce batch extension that gradually extends the shareholders＇ collaboration boundary by more than one hop at a time around the service requestor, to find at least the threshold number of the unknown shareholders. Through the batch extension, reply aggregation is applicable, hence reducing the redundancy use of reply routes, decreasing the required packet transmission, and lessening the service delay, compared to the previously proposed mechanism. Our simulation results show that, with the appropriate batch size, the latest mechanism is more efficient with an insignificant increase of control overhead.

关键词： multihop shareholder discovery threshold secret sharing multihop secret sharing

Robust backstepping global integral terminal sliding mode controller to enhance dynamic stability of hybrid AC/DC microgrids

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Protection and Control of Modern Power Systems 2023年第1期8卷 139-151页

作者： Tushar Kanti Roy Subarto Kumar ghosh Sajeeb Saha Department of Electronics&Telecommunication Engineering Rajshahi University of Engineering and TechnologyRajshahi 6204Bangladesh Department of Electrical and Electronic Engineering Rajshahi University of Engineering and TechnologyRajshahi 6204Bangladesh School of Science Technology and EngineeringUniversity of the Sunshine CoastMoreton Bay CampusQueenslandAustralia

In this paper,a Backstepping Global Integral Terminal Sliding Mode Controller(BGITSMC)with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been *** proposed approach controls the switch-ing signals of the inverter,interlinking the DC-bus with the AC-bus in an AC/DC microgrid for a seamless interface and regulation of the output power of renewable energy sources(Solar Photovoltaic unit,PMSG-based wind farm),and Battery Energy Storage *** proposed control approach guarantees the dynamic stability of a hybrid AC/DC microgrid by regulating the associated states of the microgrid system to their intended *** dynamic stabil-ity of the microgrid system with the proposed control law has been proved using the Control Lyapunov Function.A simulation analysis was performed on a test hybrid AC/DC microgrid system to demonstrate the performance of the proposed control strategy in terms of maintaining power balance while the system’s operating point ***,the superiority of the proposed approach has been demonstrated by comparing its performance with the existing Sliding Mode Control(SMC)approach for a hybrid AC/DC microgrid.

关键词： Dynamic stability Hybrid AC/DC microgrids Power balance Robust backstepping controller Global integral terminal sliding mode controller Switching control signals

Decision fusion-based approach for content-based image classification

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International Journal of Intelligent Computing and Cybernetics 2017年第3期10卷 310-331页

作者： Sudeep Thepade Rik Das Saurav ghosh Department of Information Technology Pimpri Chinchwad College of EngineeringPuneIndia Department of Information Technology Xavier Institute of Social ServiceRanchiIndia A.K.Choudhury School of Information Technology University of CalcuttaKolkataIndia

Purpose–Current practices in data classification and retrieval have experienced a surge in the use of multimedia *** of desired information from the huge image databases has been facing increased complexities for designing an efficient feature extraction *** approaches of image classification with text-based image annotation have faced assorted limitations due to erroneous interpretation of vocabulary and huge time consumption involved due to manual ***-based image recognition has emerged as an alternative to combat the aforesaid ***,exploring rich feature content in an image with a single technique has lesser probability of extract meaningful signatures compared to multi-technique feature ***,the purpose of this paper is to explore the possibilities of enhanced content-based image recognition by fusion of classification decision obtained using diverse feature extraction ***/methodology/approach–Three novel techniques of feature extraction have been introduced in this paper and have been tested with four different classifiers *** four classifiers used for performance testing were K nearest neighbor(KNN)classifier,RIDOR classifier,artificial neural network classifier and support vector machine ***,classification decisions obtained using KNN classifier for different feature extraction techniques have been integrated by Z-score normalization and feature scaling to create fusion-based framework of image *** has been followed by the introduction of a fusion-based retrieval model to validate the retrieval performance with classified *** works on content-based image identification have adopted fusion-based ***,to the best of the authors’knowledge,fusion-based query classification has been addressed for the first time as a precursor of retrieval in this ***–The proposed fusion techniques have successfull

关键词： Classification Information fusion Content-based feature extraction Retrieval

Reliability and efficiency enhancement of a radial distribution system through value-based auto-recloser placement and network remodelling

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Protection and Control of Modern Power Systems 2023年第1期8卷 1-14页

作者： Bratati ghosh Ajoy Kumar Chakraborty Arup Ratan Bhowmik Department of Electrical Engineering National Institute of Technology AgartalaJiraniaTripura 799046India

The electric distribution system(EDS)is prone to faults leading to power *** present energy market demands that electricity utilities invest more in different measures to improve the performance of the *** approach proposed here details a composite dual-phased methodology to improve the reliability and efficiency of the power delivered by the *** the first phase,the optimal allocation of auto-reclosers(AR)is undertaken by employing a newly formulated *** determination of the total number and location for AR placement is based on the economic analysis of two factors,i.e.,AR investment-maintenance cost and total benefit earned in terms of reliability improvement due to AR *** analysis also takes into account the impact of power outages on different load types,the load growth rate,and the inflation ***,to enhance the efficiency of the AR-incorpo-rated EDS,the technique of Radial Distribution System Remodelling is employed in the second *** method searches for a radial configuration that delivers power at minimum line *** phases comprising complex combinatorial operations are aided by a fresh hybrid of the Sine Cosine Algorithm,Krill Herd Algorithm,and a genetic operator of Differential *** results obtained from its application on the IEEE 69-bus distribution test system prove the credibility of the suggested formulation.

关键词： Auto-recloser placement Load flow Metaheuristic optimization algorithm Power loss minimization Reconfiguration Reliability assessment

Temperature effect on hetero structure junctionless tunnel FET

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Journal of Semiconductors 2015年第3期36卷 55-59页

作者： Shiromani Balmukund Rahi Bahniman ghosh Bhupesh Bishnoi Department of Electrical Engineering Indian Institute of Technology Kanpur Microelectronics Research Center University of Texas at Austin

For the first time, we investigate the temperature effect on AIGaAs/Si based hetero-structure junction- less double gate tunnel field effect transistor. Since junctionless tunnel FET is an alternative substitute device for ultra scaled deep-submicron CMOS technology, having very good device characteristics such as an improved sub- threshold slope （〈 60 mV/decade at 300 K） and very small static leakage currents. The improved subthreshold slope and static leakage current confirms that it will be helpful for the development of future low power switching circuits. The 2-D computer based simulation results show that OFF-state leakage current is almost temperature independent for the proposed device structure.

关键词： TFET subthreshold slope (SS) temperature effect band-to-band tunneling

Effect of Cold Deformation on Phase Evolution and Mechanical Properties in an Austenitic Stainless Steel for Structural and Safety Applications

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Journal of Iron and Steel Research International 2012年第4期19卷 63-68页

作者： S K ghosh P Mallick P P Chattopadhyay Department of Metallurgy and Materials Engineering Bengal Engineering and Science UniversityShibpurHowrah 711 103India

The effects of cold deformation on the formation of strain induced α’ martensite and mechanical properties of an austenitic stainless steel have been examined.X-ray diffraction analysis has revealed that 30% and 40% cold rolling have resulted in the formation of 24% and 31.5% martensite *** investigation has demonstrated that the formation of martensite is enhanced with increase in the percent deformation at 0 ℃.Investigation of mechanical properties reveals that hardness,yield strength and tensile strength values increase where as percent elongation drops with increasing *** fractographic observation corroborates the tensile *** of sub-surface at the fractured end of the tensile sample manifests that void/microcrack nucleation occurs in the interfacial regions of the martensite phase as well as at the austenite-martensite interface

关键词： austenitic stainless steel cold deformation martensite mechanical property

Performance Assessment of Partially Pre-fused Synthetic Flux in Basic Oxygen Steel Making

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Journal of Iron and Steel Research International 2015年第10期22卷 916-923页

作者： Jagannath PAL Satadal GHORAI Debajyoti BANDYOPADHYAY Sukomal ghosh CSIR-National Metallurgical Laboratory

Lump lime as the most common flux and iron ore as a coolant are used in basic oxygen steel making. However, high melting point, poor dissolution property, fines generation tendency and hygroscopic nature of lump lime often create problems in operation. As the combination of both iron oxide （Fe2O3） and CaO shows eutectic at 1 230 ℃, a combined mass of iron oxide and lime melts at lower temperature and dissolves faster in a molten bath. A partially pre-fused synthetic flux （PSF） was prepared through an innovative way in combination of iron oxide fines viz. Linz Donawitz converter sludge and blast furnace flue dust and lime fines by micro-pelletization of the mix followed by coke breeze free sintering. The developed PSF shows good cold handling strength, low melting point （1 180 ℃）, good thermal shock resistance, etc. As a low melting synthetic flux, its performance was assessed through dissolution/melting study in hot metal bath and refining of hot metal in a simulated bottom blown converter using （i） PSF, （ii） only lump lime and （iii） lump lime with iron ore when keeping other conditions identical. Very fast dissolution （27 80 s for 1-3 g lumps）, enhanced removal of C and P （11-12 min）, controlled slag foaming, and reduced oxygen consumption was obtained for using PSF.

关键词： synthetic flux melting refining basic oxygen converter

Dynamical system analysis of Dirac-Born-Infeld scalar field cosmology in coincident f(Q)gravity

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Chinese Physics C 2024年第9期48卷 199-209页

作者： Sayantan ghosh Raja Solanki P.K.Sahoo Department of Mathematics Birla Institute of Technology and Science-PilaniHyderabad CampusHyderabad-500078India

In this article,we present a dynamical system analysis of a Dirac-Born-Infeld scalar field in a modified f(Q)gravity *** considered a polynomial form of modified gravity,used two different types of scalar potential,polynomial and exponential,and found a closed autonomous dynamical system of *** analyzed the fixed points of such a system and evaluated the conditions under which deceleration to late-time acceleration occurs in this *** note the similarity of the two models and show that our result is consistent with a previous study on Einstein s *** also investigated the phenomenological implications of our models by plotting EoS(ω),energy density(Ω),and deceleration parameter(q)*** e-fold time and comparing to the present *** conclude the paper by observing how the dynamical system analysis differs in the modified f(Q)gravity,and present the future scope of our research.

关键词： Dirac-Born-Infeld field f(Q)gravity dark energy dynamical system analysis