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An Efficient Approach for Simulation of Water Levels due to the Nonlinear Interaction of Tide and Surge Along the Coast of Bangladesh

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China Ocean Engineering 2020年第4期34卷 537-546页

作者： Gour Chandra Paul sukumar Senthilkumar Rana Pria Department of Mathematics University of RajshahiRajshahi-6205Bangladesh School of Mathematical Sciences Universiti Sains MalaysiaPulau Pinang-11800Malaysia Mathematics Discipline ScienceEngineering&Technology SchoolKhulna UniversityKhulna-9208.Bangladesh

The ultimate goal and highlight of this paper are to explore water levels along the coast of Bangladesh efficiently due to the nonlinear interaction of tide and surge by employing the method of lines(MOLs)with the aid of newly proposed RKAHeM(4,4)*** this regard,the spatial derivatives of shallow water equations(SWEs)were discretized by means of a finite difference method to obtain a system of ordinary differential equations(ODEs)of initial valued with time as an independent *** obtained system of ODEs was solved by the RKAHeM(4,4)***-way nested grid technique was exercised to incorporate coastal complexities closely with minimum computational cost.A stable tidal oscillation was produced over the region of interest by applying the most influential tidal constituent M2 along the southern open boundary of the outer *** newly developed model was applied to estimate water levels due to the non-linear interaction of tide and surge associated with the catastrophic cyclone April 1991 along the coast of *** approach employed in the study was found to perform well and ensure conformity with real-time observations.

关键词： method of lines RKAHeM(4 4)technique error estimation storm surge nested grid

Discrete Event System Framework for Fault Diagnosis with Measurement Inconsistency:Case Study of Rogue DHCP Attack

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 789-806页

作者： Mayank Agarwal Santosh Biswas sukumar Nandi IEEE the Department of Computer Science and Engineering Indian Institute of Technology Guwahati

Fault detection and diagnosis(FDD) facilitates reliable operation of systems. Various approaches have been proposed for FDD like Analytical redundancy(AR), Principal component analysis(PCA), Discrete event system(DES) model etc., in the literature. Performance of FDD schemes greatly depends on accuracy of the sensors which measure the system *** to various reasons like faults, communication errors etc.,sensors may occasionally miss or report erroneous values of some system parameters to FDD engine, resulting in measurement inconsistency of these parameters. Schemes like AR, PCA etc.,have mechanisms to handle measurement inconsistency, however,they are computationally heavy. DES based FDD techniques are widely used because of computational simplicity, but they cannot handle measurement inconsistency efficiently. Existing DES based schemes do not use Measurement inconsistent(MI)parameters for FDD. These parameters are not permanently unmeasurable or erroneous, so ignoring them may lead to weak diagnosis. To address this issue, we propose a Measurement inconsistent discrete event system(MIDES) framework, which uses MI parameters for FDD at the instances they are measured by the sensors. Otherwise, when they are unmeasurable or erroneously reported, the MIDES invokes an estimator diagnoser that predicts the state(s) the system is expected to be in, using the subsequent parameters measured by the other sensors. The efficacy of the proposed method is illustrated using a pumpvalve system. In addition, an MIDES based intrusion detection system has been developed for detection of rogue dynamic host configuration protocol(DHCP) server attack by mapping the attack to a fault in the DES framework.

关键词： Fault diagnosis instrasion detection system (IDS) measurement inconsistent discrete event system (DES) rogue dynamic host configuration protocol (DHCP) server

Intrusion Detection System for PS-Poll DoS Attack in 802.11 Networks Using Real Time Discrete Event System

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IEEE/CAA Journal of Automatica Sinica 2017年第4期4卷 792-808页

作者： Mayank Agarwal Sanketh Purwar Santosh Biswas sukumar Nandi IEEE Department of Computer Science and Engineering ⅡT Guwahati HP PPS R&D Lab in Bangalore

Wi-Fi devices have limited battery life because of which conserving battery life is imperative. The 802.11 Wi-Fi standard provides power management feature that allows stations(STAs) to enter into sleep state to preserve energy without any frame losses. After the STA wakes up, it sends a null data or PS-Poll frame to retrieve frame(s) buffered by the access point(AP), if any during its sleep period. An attacker can launch a power save denial of service(PS-DoS) attack on the sleeping STA(s) by transmitting a spoofed null data or PS-Poll frame(s) to retrieve the buffered frame(s) of the sleeping STA(s) from the AP causing frame losses for the targeted STA(s). Current approaches to prevent or detect the PS-DoS attack require encryption,change in protocol or installation of proprietary hardware. These solutions suffer from expensive setup, maintenance, scalability and deployment issues. The PS-DoS attack does not differ in semantics or statistics under normal and attack *** signature and anomaly based intrusion detection system(IDS) are unfit to detect the PS-DoS attack. In this paper we propose a timed IDS based on real time discrete event system(RTDES) for detecting PS-DoS attack. The proposed DES based IDS overcomes the drawbacks of existing systems and detects the PS-DoS attack with high accuracy and detection rate. The correctness of the RTDES based IDS is proved by experimenting all possible attack scenarios.

关键词： Fault detection and diagnosis intrusion detection system(IDS) null data frame power save attack PS-Poll frame real time discrete event system(DES)

Phenology of Ficus *** a tropical dry forest, Mudumalai, south India

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Journal of Forestry Research 2018年第4期29卷 1117-1126页

作者： H.S.Suresh R.sukumar Center for Ecological Sciences Indian Institute of Science

The phenology of figs （Ficus spp. Moraceae） is being monitored in the dry forests of Mudumalai, southern India and individuals belonging to the genus are marked with unique tag numbers and their vegetative and reproductive phenologies have been monitored since August 2000 on a monthly basis. The influence of abiotic factors on fig phenology and the differences between fig and non- fig phenologies are being examined. The seasonality of different phenophases of fig phenology is also being examined. The maximum intensity of leaf flush occurred in drier months. Fig and non-fig species showed significant differences with expansion and senescence phenophases of leafing. Flowering also occurred in drier months. There were significant differences between fig and non-fig species with reproductive phenophases. As with non-fig species, leafing was influenced by maximum temperatures. Both vegetative and reproductive phenophases were significantly seasonal.

关键词： Dry forests Figs Non-figs Multipleregression Phenology Seasonality

Storm surge simulation along the Meghna estuarine area:an alternative approach

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Acta Oceanologica Sinica 2018年第1期37卷 40-49页

作者： PAUL Gour Chandra SENTHILKUMAR sukumar PRIA Rana Department of Mathematics University of Rajshahi School of Mathematical Sciences Universiti Sains Malaysia Mathematics Discipline Khulna University

In this study, numerical prediction of surges associated with a storm was made through the method of lines（MOL） in coordination with the newly proposed RKARMS（4, 4） method for the meghna estuarine region, along the coast of Bangladesh. For this purpose, the vertically integrated shallow water equations（SWEs） in Cartesian coordinates were firstly transformed into ordinary differential equations（ODEs） of initial valued, which were then soloved using the new RKARMS（4, 4） method. Nested grid technique was employed for resolving the complexities of the region of interest with minimum cost. Fresh water discharge through the lower Meghna River was taken into account along the north east corner of the innermost child scheme. Numerical experiments were performed with the severe cyclone on April 1991 that crossed the coast over the study area. Simulated results by the study were found to be in good agreement with some reported data and were found to compare well with the results obtained by the MOL in addition with the classical 4th order Runge-Kutta（RK（4, 4）） method and the standard finite difference method（FDM）.

关键词： method of lines storm surge nested grid finite difference method RKARMS (4, 4) method truncation errors

A Standalone BLDC Based Solar Air Cooler with MPP Tracking for Improved Efficiency

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CSEE Journal of Power and Energy Systems 2019年第1期5卷 111-119页

作者： Sreedhar Madichetty Deepak Pullaguram sukumar Mishra Indian Institute of Technology DelhiNew DelhiIndia

This article proposes the idea of using Solar Energy(SE)as a source of power for designing and developing a standalone air-cooling *** type of application is particularly suited for rural areas that have a considerable amount of solar radiation and have no access to grid *** proposed system is comprised of a photovoltaic(PV)array,DC-DC boost converter and DC-DC buck *** Permanent Magnet Brushless Direct Current(PMBLDC)motors are employed to drive a centrifugal water pump and an air blower coupled to their individual *** air blower is connected with a DCDC boost converter that ensures a maximum power point(MPP)operation.A centrifugal water pump is connected with a DC-DC buck *** challenging task in an air cooling system is to maintain the constant speed of the blower under variable irradiance *** power provided by the solar PV array can be shared between the two DC-DC converters in such a way that the BLDC motor connected with the blower will maintain a constant speed by maintaining the constant voltage of the DCDC boost *** rest of the available PV power will be handled by the *** suitability of the proposed system for various perturbations is evaluated by simulating the proposed system using a MATLAB/Simulink and is validated by conducting *** studies have been performed with a variable PV irradiance and the results are explored.

关键词： BLDC air blower BLDC motor BLDC Pump PV System

Experimental and modeling study of kinetics for methane hydrate formation in a crude oil-in-water emulsion

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Petroleum Science 2016年第3期13卷 489-495页

作者： Shranish Kar Himangshu Kakati Ajay Mandal sukumar Laik Department of Petroleum Engineering Indian School of Mines

A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a *** differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate formation in flow channels,varying amount of crude oil in water emulsion without any other extraneous additives has undergone methane gas hydrate formation in an autoclave *** oil was able to thermodynamically inhibit the gas hydrate formation as observed from its hydrate stability *** normalized rate of hydrate formation in the emulsion has been calculated from an illustrative chemical affinity model,which showed a decrease in the methane consumption（decreased normalized rate constant） with an increase in the oil content in the *** transform infrared spectroscopy（FTIR） of the emulsion and characteristic properties of the crude oil have been used to find the chemical component that could be pivotal in selfinhibitory characteristic of the crude oil collected from Ankleshwar,India,against a situation of clogged flow due to formation of gas hydrate and establish flow assurance.

关键词： Methane gas hydrates Organic inhibitors Chemical affinity model Normalized rate constant Asphaltenes

Electrochemical Study of Diffusion Bonded Joints between Micro-duplex Stainless Steel and Ti6A14V Alloy

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Journal of Materials Science & Technology 2014年第2期30卷 163-171页

作者： Shaily M.Bhola sukumar Kundu Rahul Bhola Brajendra Mishra Subrata Chatterjee Department of Metallurgical and Materials Engineering Colorado School of Mines Department of Metallurgy and Materials Engineering Bengal Engineering and Science University

In the present study, corrosion behavior of diffusion bonded joints formed between micro-duplex stainless steel （MDSS） and Ti6AI4V alloy （TiA）（at 900 ~C for 60 min under 4 MPa uniaxial pressure in vacuum） was investigated in 1 mol/L HCI and 1 mol/L NaOH solutions using various electrochemical measurements such as open circuit potential （OCP）, electrochemical impedance spectroscopy （EIS） and potentiodynamic polarization （PD）. For comparison, corrosion behavior of base metals （MDSS and TiA） was also evaluated. Bonded joint was characterized by light optical microscopy and scanning electron microscopy using backscattered electron mode. The layer wise σ phase and λ ＋ FeTi phase mixture has been observed at the bond interface and the bond tensile strength and shear strength were - 556.4 MPa and -420.2 MPa, respectively.

关键词： Diffusion bonding Micro-duplex stainless steel Titanium ahoy Corrosion EIS

Methane hydrate formation and dissociation in synthetic seawater

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Journal of Natural Gas Chemistry 2012年第6期21卷 625-632页

作者： Vikash Kumar Saw Iqbal Ahmad Ajay Mandal G.Udayabhanu sukumar Laik Gas Hydrate Laboratory Department of Petroleum Engineering Department of Applied Chemistry Indian School of Mines

The formation and dissociation of methane gas hydrate at an interface between synthetic seawater （SSW） and methane gas have been experimentally investigated in the present work. The amount of gas consumed during hydrate formation has been calculated using the real gas equation. Induction time for the formation of hydrate is found to depend on the degree of subcooling. All the experiments were conducted in quiescent system with initial cell pressure of 11.14 MPa. Salinity effects on the onset pressure and temperature of hydrate formation are also observed. The dissociation enthalpies of methane hydrate in synthetic seawater were determined by Clausius-Clapeyron equation based on the measured phase equilibrium data. The dissociation data have been analyzed by existing models and compared with the reported data.

关键词： methane hydrate formation and dissociation total dissolved salt induction time subcooling