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Edge Detection of River in SAR Image Based on Contourlet Modulus Maxima and Improved Mathematical Morphology

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Transactions of Nanjing University of Aeronautics and Astronautics 2014年第5期31卷 478-483页

作者：吴一全朱丽郝亚冰李立卢文平 College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Engineering technology Research Center of Wuhan Intelligent Basin Changjiang River Scientific Research InstituteChangjiang Water Resources Commission of the Ministry of Water Resources Key Laboratory of the Yellow River Sediment of Ministry of Water Resource Yellow River Institute of Hydraulic Research Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research Institute State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology

To cope with the problems that edge detection operators are liable to make the detected edges too blurry for synthetic aperture radar(SAR)images,an edge detection method for detecting river in SAR images is proposed based on contourlet modulus maxima and improved mathematical *** SAR image is firstly transformed to a contourlet *** to the directional information and gradient information of directional subband of contourlet transform,the modulus maximum and the improved mathematical morphology are used to detect high frequency and low frequency sub-image edges,***,the edges of river in SAR image are obtained after fusing the high frequency sub-image and the low frequency *** results demonstrate that the proposed edge detection method can obtain more accurate edge location and reduce false edges,compared with the Canny method,the method based on wavelet and Canny,the method based on contourlet modulus maxima,and the method based on improved(ROEWA).The obtained river edges are complete and clear.

关键词： synthetic aperture radar(SAR) image river detection edge detection contourlet transform modulus maxima

Numerical Investigations on Harbor Oscillations Induced by Falling Objects

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China Ocean Engineering 2023年第3期37卷 458-470页

作者： GAO Jun-liang BI Wen-jing ZHANG Jian ZANG Jun School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources Guangzhou 510611China Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYUK

In this paper,the open-sourced computational fluid dynamics software,OpenFOAM~?,is used to study the fluctuation phenomenon of the water body inside a horizontally one-dimensional enclosed harbor basin with constant water depth triggered by falling wedges with various horizontal falling positions,initial falling velocities and *** on both Fourier transfo rm analysis and wavelet spectrum analysis for the time series of the free surface elevations inside the harbor basin,it is found for the first time that the wedge falling inside the harbor can directly trigger harbor *** influences of the three factors(including the horizontal falling position,the initial falling velocity,and the mass)on the response amplitudes of the lowest three resonant modes are also *** results show that when the wedge falls on one of the nodal points of a resonant mode,the mode would be remarkably ***,when the wedge falls on one of the anti-nodal points of a resonant mode,the mode would be evidently *** initial falling velocity of the wedge mainly has a remarkable effect on the response amplitude of the most significant mode,and the latter shows a gradual increase trend with the increase of the *** for the other two less significant modes,their response amplitudes fluctuate around certain constant values as the initial falling velocity *** general,the response amplitudes of all the lowest three modes are shown to gradually increase with the mass of the wedge.

关键词： harbor oscillations seiches falling objects resonant mode response amplitude

Influences of Floater Motion on Gap Resonance Triggered by Focused Wave Groups

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中国海洋工程:英文版 2023年第4期37卷 685-697页

作者： GAO Jun-liang LYU Jing ZHANG Jian ZANG Jun School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources Guangzhou 510611China Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYUK

The current study investigates the hydrodynamic characteristics of gap resonance within a narrow gap formed by two adjacent boxes subjected to incident focused transient wave groups.A two-dimensional(2D)numerical wave tank based on the OpenFOAM package is utilized for this *** weather-side box is fixed while the lee-side box is allowed to heave freely under wave *** effects of the focused wave amplitude and spectral peak period on the wave amplification within the gap,motion of the lee-side box,and wave forces(including horizontal and vertical wave forces)acting on each box are systematically *** comparison,another structural layout consisting of two fixed boxes is also *** results reveal that the release of the heave degree of freedom(DoF)of the lee-side box results in remarkably distinct resonance *** the heave-box system,both its fluid resonant period and the period corresponding to the maximum heave displacement of the lee-side box are significantly larger(i.e.,1.6-1.7 times)than the fluid resonant period of the fixed-box ***,the wave amplification factor inside the gap in the heave-box system is significantly lower than that in the fixed-box *** the variations of the maximum horizontal and vertical wave forces with the spectral peak period and their magnitudes are also significantly different between the two structural systems.

关键词： gap resonance focused waves wave amplification wave forces OpenFOAM

Experimental Study on the Influencing Factors of Motion Responses on an Air-Floating Caisson with Multiple Compartments

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Journal of Ocean University of China 2022年第1期21卷 39-48页

作者： LIU Xianqing ZHANG Puyang ZHAO Mingjie DING Hongyan LE Conghuan LV Nan LUO Sheng State Key Laboratory of Hydraulic Engineering simulation and Safety Tianjin UniversityTianjin 300072China National Engineering Research Center for Inland waterway Regulation Chongqing Jiaotong UniversityChongqing 400074China Department of Military Facilities Army Logistics University of PLAChongqing 401331China

The structure of an air-floating caisson is suitable for the major structure of caisson-type artificial ***,it has been rapidly developed and widely used in the exploration and development of oil and gas fields in shallow sea and intertidal ***-floating transportation technology is one of the key technologies employed in this *** this paper,the factors influencing the dynamic response characteristics of air-floating caisson with multi-compartments(AFCMC)were studied using model *** length and the height of each air-floating structure in the model were 1.0 and 0.1 m,*** addition,the 1:100 models with 6,8,and 10 compartments under regular waves were tested in the wave flume,*** the experiments,the respective water depths were set at 0.2,0.3,and 0.4 m,and the corresponding drafts were 0.05,0.06,and 0.07 *** show that with the increase of draft,the heave natural period increased and the maximum amplitude of the heave motion ***,the pitch motion decreased at 6 and 8 compartments and increased at 10 *** the water depth increased,the maximum amplitude and amplitude change of heave and pitch motions first increased and then ***,several amplitudes close to the maximum amplitude appeared in the measured period at shallower water depth,thereby indicating the vertical movements of the structure enhanced under shallow *** increase in the number of compartments reduced the vertical movements under 6.0 m draft,but it increased the vertical movements under 5.0 and 7.0 m ***,increasing the number of compartments has a limited capacity to improve the motion performance of the structure.

关键词： air-floating caisson structure response amplitude operator(RAO) draft water depth compartment

Study on Transient Gap Resonance with Consideration of the Motion of Floating Body

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China Ocean Engineering 2022年第6期36卷 994-1006页

作者： GAO Jun-liang LYU Jing WANG Jing-hua ZHANG Jian LIU Qian ZANG Jun ZOU Tao School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China Department of Civil and Environmental Engineering the Hong Kong Polytechnic UniversityHong KongChina Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYU.K Shandong Provincial Key Laboratory of Ocean Engineering Qingdao 266100China

In this paper, the transient fluid resonance phenomenon inside a narrow gap between two adjacent boxes excited by the incident focused waves with various spectral peak periods and focused wave amplitudes is simulated by utilizing the open-sourced computational fluid dynamics software, Open FOAM. The weather-side box is allowed to heave freely under the action of waves, and the lee-side box keeps fixed. This paper mainly focuses on how both the spectral peak period and the focused wave amplitude affect the free-surface amplification inside the gap, the motion of the weather-side box, and the wave loads(including the vertical and the horizontal wave forces) acting on both *** comparison, another two-box system with both boxes fixed is also considered as a control group. It is found that the motion of the weather-side box significantly changes the characteristics of the transient gap resonance, and it would cause that the fluid resonant period becomes 1.4-1.6 times that of the two-box system with both boxes *** the concerned physical quantities(i.e., the free-surface amplification in the gap, the motion of the weather-side box, the wave loads) are found to closely depend on both the spectral peak period and the focused wave amplitude.

关键词： transient gap resonance focused waves free-surface amplification wave loads heave motion OpenFOAM

Wash Waves Generated by High Speed Displacement Ships

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China Ocean Engineering 2015年第5期29卷 757-770页

作者：周利兰高高 R.H.M.Huijsmans Key Laboratory of High Performance Ship technology Ministry of Education Wuhan University of Technology School of Transportation Wuhan University of Technology Delft University of technology

It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible.

关键词： wash waves wave generation model wave spectrum method Boussinesq type equation wave model motions of moored ship

Stability and Influence Factors Analysis of Wharf Slope on Slippery Stratum

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International Journal of technology Management 2014年第7期 34-37页

作者： LI Peng-fei LIU Ming-wei DAI Ru-lin National Engineering Research Center for Inland waterway Regulation Chongqing Jiaotong University Chongqing 400074 China Key Laboratory of Hydraulic and waterway Engineering of Ministry of Education Chongqing Jiaotong University Chongqing 400074 China Chongqing Surveying and Design Institute of Water Electric Power and Architecture Chongqing 400020 China

With the growing tension of port shoreline resource in Three Gorges Reservoir area, many wharfs can only be constructed on slippery stratum with poor geological condition, which means buckling failure occurs easily. FEM strength reduction method is used in analyzing slope stability of a wharf in Chongqing, and its accuracy is verified by comparing the acquired results with the computation of traditional limit equilibrium method. On this basis, the influences of reservoir water level variation, overload and backfill material behind the retaining wall, and soil share strength of wharf slope on slippery stratum are analyzed. Analysis shows that, there＇ s a most adverse water level in wharf slope, and the engineering proposals with a certain practical significance such as improve the drainage behind retaining wall, controll overload and improve the strength of backfill soil and subsoil are suggested.

关键词： slippery stratum stability factors analysis strength reduction method

对船舶操纵性标准的急迫需求——休斯敦水道实船操纵性试航的经验

维普期刊数据库评论

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维普期刊数据库

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上海造船 2006年第2期 55-62页

作者： Alexander C.Landsburg Roderick A.Barr Larry Daggett Wei-Yuan Hwang Bent Jakobsen Mike Morris Lou Vest U.S.Mariti me Administration WashingtonDCUSA. Hydronautics Research Inc.GaithersburgMarylandUSA. waterway si mulation technology Inc.VicksburgMississippiUSA. U.S.Merchant Marine Academy Mariti me AdministrationKings PointNew YorkUSA. Computer Sciences Corporation Advanced Marine CenterWashing-tonDCUSA. Houston Pilots Association HoustonTexasUSA. Houston

我认为,造船师和轮机师考虑海上环境设计的船舶,它们99.9%的时间在海上渡过.但他们忘了,这些船舶还必须进入河道装卸货物.当某件引起公众高度关注的事故发生,船舶建造者或许会进入公众视线,发现他们犯有疏忽罪,要为建造了动力不足和操... 详细信息

我认为,造船师和轮机师考虑海上环境设计的船舶,它们99.9%的时间在海上渡过.但他们忘了,这些船舶还必须进入河道装卸货物.当某件引起公众高度关注的事故发生,船舶建造者或许会进入公众视线,发现他们犯有疏忽罪,要为建造了动力不足和操纵不良的船舶负责.

关键词：船舶操纵性上海市造船工程学会试航实船水道休斯需求标准双向交流论文

Performance simulation and optimization of new radiant floor heating based on micro heat pipe array

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Building simulation 2022年第7期15卷 1295-1308页

作者： Heran Jing Zhenhua Quan Ruixue Dong Limin Hao Yunhan Liu Yaohua Zhao Beijing Key Laboratory of Green Built Environment and Energy Efficient technology Beijing University of TechnologyBeijing 100124China

This paper proposes two new radiant floor heating structures based on micro heat pipe array(MHPA),namely cement-tile floor and keel-wood *** numerical models for these different floor structures are established and verified by *** temperature distribution and heat transfer process of each part are comprehensively obtained,and the structure is *** results show that the cement-tile floor has the better heat transfer performance of the *** under the same inlet water temperature and flow rate,the keel-wood floor's surface temperature distribution is about 2℃ lower than that of the cement-tile *** inlet water temperature of cement-tile floor is about 10℃ lower than that of keel-wood structure when the floor surface temperature is the *** a longitudinal heat transfer above MHPA,the floor surface temperature decreases by 0.5℃ for every 10 mm filling layer *** order to reduce the non-uniformity of the floor's surface temperature and improve the thermal comfort of the heated room,the optimal structure for a floor is given,with the maximum surface temperature difference reduced by 3.35℃.We used research focusing on new radiant floor heating,with advantages including high efficiency heat transfer,low water supply temperature,simple waterway structure,low resistance and leakage risk,to provide theory and data to support the application of an effective radiant floor heating based on MHPA.

关键词： radiant floor heating micro heat pipe array numerical simulation heat transfer