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Forty-year investigation of wave power in energetic region of Persian Gulf in Iranian territorial waters by using short-term and new long-term stability assessment parameters

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Acta Oceanologica Sinica 2023年第10期42卷 75-83页

作者： Fouad Salimi Cyrus Ershadi vahid chegini Department of Civil Engineering University of HormozganBandar Abbas *** P.OBOX:3995Iran Department of Coastal Engineering Islamic Azad University(Central Tehran Branch)Tehran ***Iran

The wave power in high potential area of the northern Persian Gulf(near to Iranian coastal areas)is assessed by taking into account the temporal and spatial distributions of wave power for a period of forty *** this purpose,assimilated wind data of European Centre for Medium-Range Weather Forecasting Interim Reanalysis(ERA-Interim),and hydrography data of General Bathymetric Chat of the oceans(GEBCO)are used as SWAN *** locations are investigated in the study area by considering the amount of coefficient of variation,the amount of average annual power,and the short-term and a new long-term(decadal variability index)power stability assessment *** results showed more stability in the eastern parts of the study area and concluded that a narrow line between the point which is in the middle and another point which is in the eastern middle part of the study area may be the best locations for more investigation and the feasibility study for energy converter ***,it is found that the middle part of the study region with about 2.5 kW/m power is the most energetic *** is concluded that the dominant direction of wave power distribution in all points is the northeast,and this dominant direction has not changed during the forty-year *** is observed that the mean annual energy increases with a slight slope in the total 40 a,and this increasing trend is more obvious in the fourth *** it is observed that the wave power of the second decade has the most stability and the least variation,the wave power in the fourth decade has the most ***,the results showed that the study region’s wave power increase by approximately a mean change rate of 0.027 kW/(m·a);and the maximum change rate of wave power was in the northwest part and the minimum change rate of wave power was in the southeast part which were about 0.036 kW/(m·a)and 0.014 kW/(m·a),respectively.

关键词： wave energy SWAN model wind assimilated data Persian Gulf numerical modeling decadal assessment

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Seasonal variation of the double diffusion processes at the Strait of Hormuz

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Acta Oceanologica Sinica 2017年第1期36卷 26-34页

作者： AZIZPOUR Jafar chegini vahid SIADATMOUSAVI Seyed Mostafa Iranian National Institute for Oceanography and Atmospheric Science Tehran ***Iran Iran University of Science and Technology Tehran ***Iran

Profiles of salinity and temperature were measured in the strait of Hormuz（SH） during the winter of 2012, spring and summer of 2013. To investigate the double diffusion（DD） processes, Turner（TU） angle values are calculated in all the stations in the SH. Different TU angle values correspond to salt fingering（SF）, diffusive convection（DC）and stable stratification. The distributions of the two forms of DD were plotted vertically along transects in the eastern, central and western part of the SH, and corresponding DD processes were described. The results show that both SF and DC occurred in most part of the study area. Two different water masses（the Indian Ocean surface water and the Persian Gulf water） were evident at the SH, and SF and DC were evident at the interface of two water masses. Due to evaporation, SF occurred in the surface layer of most Stations throughout the year. In the eastern part of the SH, occurrences of DC were more feasible in wintertime. SF was the main phenomenon at the end of hot season. For central part, SF occurred throughout the year in water column. In the western part,water column was stable in summer and DC happened in most part of water column in winter.

关键词： double diffusion diffusive convection salt fingering Turner angle Strait of Hormuz

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Spectral Wave Modeling in Very Shallow Water at Southern Coast of Caspian Sea

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Journal of Marine Science and Application 2018年第1期17卷 140-151页

作者： Seyed Masoud Mahmoudof Peyman Badiei Seyed Mostafa Siadatmousavi vahid chegini Iranian National Institute for Oceanography and Atmospheric Sciences(INIOAS) Tehran ***Islamic Republic of Iran School of Civil Engineering College of EngineeringUniversity of TehranP.O.Box 11155-4563TehranIran School of Civil Engineering Iran University of Science and TechnologyNarmakTehran ***Iran

This study evaluates the capability of the Simulating WAves Nearshore(SWAN)wave model(version 41.01)in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf zone during depth-induced wave breaking and *** model results were compared with field measurements at five nearshore *** results demonstrated that some breaker index formulations were successful for significant wave height prediction in surf ***,an incorrect shape of the energy spectrum and overestimated near spectral peak energy content at shallow water stations were obtained using all of the embedded depth-induced wave breaking formulations in *** dependent breaker index on relative depth(Kpd)formulation,which was successful in predicting near spectral peak energy content,resulted in an average error of 30%.Finally,this formulation was modified to enhance the model performance in reproducing the spectral peak energy content.

关键词： Caspian Sea Shallow water SWAN Spectral peak energy Coastal processes

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Modeling of the Changes in Flow Velocity on Seawalls under Different Conditions Using FLOW-3D Software

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Open Journal of Marine Science 2016年第2期6卷 317-322页

作者： Maryam Deilami-Tarifi Mehdi Behdarvandi-Askar vahid chegini Sadegh Haghighi-Pour Department of Coastal Engineering Khorramshahr University of Marine Science and Technology Khorramshahr Iran Department of Marine Structures Khorramshahr University of Marine Science and Technology Khorramshahr Iran Iran National Center for Oceanography and Atmospheric Sciences Tehran Iran Department of Civil Engineering Excellence in Education Center of Jihad University of Khuzestan Ahvaz Iran

Seawalls are among protective structures that are constructed for decreasing the level of wave force and/or protecting from other structures. In this regard, more accurate investigation of these structures takes great importance from different perspectives. This research investigates the change of the velocity on seawall crown by considering the obstacles in different layouts and slopes. FLOW-3D has been used in this research for modeling. The results of the modeling show that the existence of obstacles has a determinative role in decreasing flow rate in the crown of seawalls. Also, as it was expected, the slope factor on upstream seawalls is very determinative in decreasing this rate such that the lowest velocity on the wall occurs in D-state layout and the slope of 45°.

关键词： Flow Velocity Seawall Crown Modeling FLOW-3D

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A Stable Numerical Scheme Based on the Hybridized Discontinuous Galerkin Method for the Ito-Type Coupled KdV System

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Communications on Applied Mathematics and Computation 2022年第4期4卷 1351-1373页

作者： Shima Baharlouei Reza Mokhtari Nabi chegini Department of Mathematical Sciences Isfahan University of Technology84156-83111 IsfahanIran Department of Mathematics Tafresh University39518-79611 TafreshIran

The purpose of this paper is to develop a hybridized discontinuous Galerkin(HDG)method for solving the Ito-type coupled KdV *** fact,we use the HDG method for discre-tizing the space variable and the backward Euler explicit method for the time *** linearize the system,the time-lagging approach is also *** numerical stability of the method in the sense of the L2 norm is proved using the energy method under certain assumptions on the stabilization parameters for periodic or homogeneous Dirichlet bound-ary *** experiments confirm that the HDG method is capable of solving the system *** is observed that the best possible rate of convergence is achieved by the HDG ***,it is being illustrated numerically that the corresponding con-servation laws are satisfied for the approximate solutions of the Ito-type coupled KdV *** to the numerical experiments,it is verified that the HDG method could be more efficient than the LDG method for solving some Ito-type coupled KdV systems by comparing the corresponding computational costs and orders of convergence.

关键词： Hybridized discontinuous Galerkin(HDG)method Stability analysis Ito-type coupled KdV system Conservation laws

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Interactive visual labelling versus active learning:an experimental comparison

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Frontiers of Information Technology & Electronic Engineering 2020年第4期21卷 524-535页

作者： Mohammad chegini Jurgen BERNARD Jian CUI Fatemeh chegini Alexei SOURIN Keith ANDREWS Tobias SCHRECK Institute of Computer Graphics and Knowledge Visualisation Graz University of TechnologyGraz 8010Austria School of Computer Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore InfoVis Group University of British ColumbiaVancouver V6T1Z4Canada Max Planck Institute for Meteorology Hamburg 20146Germany Institute of Interactive Systems and Data Science Graz University of TechnologyGraz 8010Austria

Methods from supervised machine learning allow the classification of new data automatically and are tremendously helpful for data *** quality of supervised maching learning depends not only on the type of algorithm used,but also on the quality of the labelled dataset used to train the *** instances in a training dataset is often done manually relying on selections and annotations by expert analysts,and is often a tedious and time-consuming *** learning algorithms can automatically determine a subset of data instances for which labels would provide useful input to the learning *** visual labelling techniques are a promising alternative,providing effective visual overviews from which an analyst can simultaneously explore data records and select items to a *** putting the analyst in the loop,higher accuracy can be achieved in the resulting *** initial results of interactive visual labelling techniques are promising in the sense that user labelling can improve supervised learning,many aspects of these techniques are still largely *** paper presents a study conducted using the mVis tool to compare three interactive visualisations,similarity map,scatterplot matrix(SPLOM),and parallel coordinates,with each other and with active learning for the purpose of labelling a multivariate *** results show that all three interactive visual labelling techniques surpass active learning algorithms in terms of classifier accuracy,and that users subjectively prefer the similarity map over SPLOM and parallel coordinates for *** also employ different labelling strategies depending on the visualisation used.

关键词： Interactive visual labelling Active learning Visual analytics

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Automated measurement of moving grains on bed deposits

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International Journal of Sediment Research 2011年第3期26卷 304-317页

作者： Amir H.N.chegini Simon TAIT Lecturer of Civil Engineering Department Faculty of EngineeringUniversity of GuilanMain CampusI.R.of Iran School of Engineering Design and TechnologyUniversity of BradfordBradfordBD7 1DPUK.

The performance of gravel bedload predictor equations is particularly poor.A key reason for this situation is the current poor understanding of the physical mechanisms that are involved in the entrainment of grains from water-worked sediment *** has been caused,in part,by a lack of detailed data on the behaviour of moving sediment *** this study,observations of the entrainment, transport and deposition of many particles from a gravel bed has been collected and studied using an image-based *** system was used to measure the motion of hundreds of gravel particles moving as *** paper describes the development of the image-based system and the data processing methods used to provide the automated measurement of particle *** system was adapted from commercially available PIV equipment and was configured to obtain simultaneously data for the analysis of the moving grains and the near-bed flow *** techniques developed are relatively sensitive to sediment colour and shape by using related image processing algorithms and so could be applied to natural gravel *** results(image data)obtained from the techniques developed are amended in a program by using two functions(commands)of image processing called "Label2RGB",and "RegionProps" which distinguish the colour and shape of moving sediment grains *** data processing provided information that identified individual grain entrainments,*** accurately traced the motion of some,but not all,*** show that the system was able to estimate grain entrainment rates and indicate locations of preferential entrainment and deposition from data on hundreds of individual moving grains.

关键词： Uniform flow Bed load Sediment transport Measurement Image processing

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Numerical Simulation of Coupled Nonlinear Schrodinger Equations Using the Generalized Differential Quadrature Method

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Chinese Physics Letters 2011年第2期28卷 5-8页

作者： R.Mokhtari A.Samadi Toodar N.G.chegini Department of Mathematical Sciences Isfahan University of TechnologyIsfahan 84156-83111Iran Department of Mathematics Tafresh UniversityTafresh 39518-79611Iran

We the extend application of the generalized differential quadrature method(GDQM)to solve some coupled nonlinear Schr(o)dinger *** cosine-based GDQM is employed and the obtained system of ordinary differential equations is solved via the fourth order Runge-Kutta *** numerical solutions coincide with the exact solutions in desired machine precision and invariant quantities are conserved *** comparisons with the methods applied in the literature are carried out.

关键词： method invariant ordinary

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Application of the Generalized Differential Quadrature Method in Solving Burgers' Equations

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Communications in Theoretical Physics 2011年第12期56卷 1009-1015页

The aim of this paper is to obtain numerical solutions of the one-dimensional,two-dimensional and coupled Burgers' equations through the generalized differential quadrature method(GDQM).The polynomial-based differential quadrature(PDQ) method is employed and the obtained system of ordinary differential equations is solved via the total variation diminishing Runge-Kutta(TVD-RK) *** numerical solutions are satisfactorily coincident with the exact *** method can compete against the methods applied in the literature.

关键词： Burgers方程广义微分求积法应用常微分方程数值解 PDQ 多项式 TVD

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Sunflower petals:Some physical properties and modeling distribution of their number,dimensions,and mass

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Information Processing in Agriculture 2018年第2期5卷 185-198页

作者： Amir Hossein Mirzabe Golam Reza chegini Javad Khazaei Department of Mechanical Engineering of Biosystems Faculty of Agricultural Engineering and TechnologyCollege of Agriculture&Natural ResourcesUniversity of TehranTehranIran Department of Mechanical Engineering of Biosystems College of AboureihanUniversity of TehranTehranIran

Sunflower petal is one of the parts of the sunflower which has drawn attention and has several applications these *** applications justify getting information about physical properties,mechanical properties,drying trends,*** order to design new machines and use new methods to harvest or dry the sunflower *** three varieties of sunflower,picking force of petals was measured;number of petals of each head was counted;unit mass and 1000-unit mass of fresh petals were measured and length,width,and projected area of fresh petals were calculated based on image processing technique;frequency distributions of these parameters were modeled using statistical distribution models namely Gamma,Generalized Extreme Value(G.E.V),Lognormal,and *** of picking force showed that with increasing number of days after appearing the first petal on each head from 5 to 14 and decreasing loading rate from 150 gmin^-1 to 50 g min^-1 values of picking force were decreased for three varieties,but diameter of sunflower head had different effects on picking force for each ***,width,and number of petals of Dorsefid variety ranged from 38.52 to 95.44 mm,3.80 to 9.28mm and 29 to 89,*** corresponding values ranged from 34.19 to 88.18 mm,4.28 to 10.60 mm and 21 to 89,respectively for Shamshiri variety and ranged from 44.47 to 114.63 mm,7.03 to 20.31 mm and 29 to 89 for Sirena *** of frequency distribution modeling indicated that in most cases,G.E.V and Weibull distributions had better performance than other distributions.

关键词： Sunflower(Helianthus annus L.)petal Picking force Image processing Fibonacci sequence Lucas sequence

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