To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D mode...To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in theelds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling.展开更多
Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with a...Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions for the(3+1)-dimensional Virasoro integrable model,including the interaction solution between a kink and a soliton,the lump-type solution and periodic solutions,have been studied analytically and graphically.展开更多
In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent techno...In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent technology education and digital reform,the combination of virtual reality and campus management is the need for innovative thinking and economic and social development,and then better change our learning style and living environment.The construction of the digital campus is based on virtual reality technology,BIM,GIS,and three-dimensional modeling technology to provide an immersive platform for students,promote the integration of virtual reality technology and education,help teachers,students,and parents to understand all kinds of education information and resources,to achieve their interoperability.From the off-campus environment to the school teaching equipment,teachers to teaching quality certification,and learning,to extracurricular entertainment,opening ceremonies to graduation parties,to bring more efficient,convenient,and safe campus life for teachers,students,and staff in school,and break the traditional information restrictions.展开更多
With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to t...With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering.展开更多
The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its ma...The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data展开更多
With the coming of information age and the development of computer science, digitalization of whole garment is becoming more and more important. The surface of whole garment is sequent and glossy so that it is lack of...With the coming of information age and the development of computer science, digitalization of whole garment is becoming more and more important. The surface of whole garment is sequent and glossy so that it is lack of the texture characteristic which is the key of digital 3D modeling. According to this reason, the structure illumination is steered into a method of this paper. The paper proposes the method by which 3D model of whole garment is created from 2D image sequences directly but not by the common techniques using general CAD model. In the paper the structure illumination is generated by the slide projector and the modeling of whole garment is based on the strict theory of the digital photogrammetry, computer vision and image processing pattern recognition. Because whole garment is lack of the applicable texture for matching, the characteristic texture generated by the structure illumination is added onto the surface of whole garment. After the characteristic texture is extracted from images and is matched well, 3D coordinates of the characteristic texture can be calculated out by the space forward intersection. Then the whole garment model is acquired by connecting all neighhour space points in the TIN and rendering the real texture of whole garment automatically. The 3D modeling method is untouched so that it is nondestructive which is just suitable for the messaline and the clothing. The method of whole garment 3D modeling proposed in the paper is flexible, effective and practical, which is confirmed by the results of the reconstructing experiments.展开更多
The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and ...The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and air temperature field at the 1000 mb level from the European Centre for Medium-Range Weather Forecasts as inputs. The boundary conditions at Bashi Channel and Taiwan Strait are taken from the simulation results of the Kuroshio using the same numerical model with a grid size of 0.5°×0.5° and the results of Cai and Li (1996) as boundary conditions. The computational domain for the present paper is between 100°E and 123°E and between 4.5°N and 27°N. The horizontal resolution is 0.25°×0.25° and the vertical variations of the velocity components are resolved by 6 layers The computed steady flow, temperature and elevation fields are consistent with the corresponding fields observed. In particular, the temperature and elevation fields of the South China Sea Warm Current (SCSWC) have been successfully simulated. The paths of the branch of the Kuroshio entering the South China Sea (SCSBK) through Bashi Channel in winter and summer are discussed It is found that the SCSBK flows southward to the southern SCS from the coast of the Guangdong Province. A portion of the SCSBK returns to the Bashi Channel and subdivides again in deep waters in winter with a branch flows to the south along the coast of the Philippines instead of flowing back to the Pacific In addition, our results confirm the existence of a eastward current to the northeast of Dongsha in summer with the Kuroshio as its source as suggested by Huang et al. Since the value of the eddy viscosity adopted for the simulation of the Kuroshio is on the high side, resulting in a weaker west boundary current in the western Pacific as the boundary conditions for the present simulations, some deviations from the actual situations are expected although the results are in general consistent with observations.展开更多
The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional method...The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional methods for creating digital surface models are insufficient to reflect the details of earth’s features. These models only represent three-dimensional objects in a single texture and fail to offer a realistic depiction of the real world. Furthermore, the need for current and precise geographic information regarding urban areas has been increasing significantly. This study proposes a new technique to address this problem, which involves integrating remote sensing, Geographic Information Systems (GIS), and Architecture Environment software environments to generate a detailed three-dimensional model. The processing of this study starts with: 1) Downloading high-resolution satellite imagery; 2) Collecting ground truth datasets from fieldwork; 3) Imaging nose removing; 4) Generating a Two-dimensional Model to create a digital surface model in GIS using the extracted building outlines; 5) Converting the model into multi-patch layers to construct a 3D model for each object separately. The results show that the 3D model obtained through this method is highly detailed and effective for various applications, including environmental studies, urban development, expansion planning, and shape understanding tasks.展开更多
The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the abili...The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the ability of 3-D digital elevation models (DEMs) derived from high accurate data to assess and quantify beach morphodynamics in relation with wave forcing. The methodology and data acquisition are described and consist mainly in the production of interpolated DEMs from which a variety of representations can be made, including as elevation change maps, two-dimensional cross-sections of the beach, calculation of net volume. The results of the analysis highlight seasonal changes in beach morphology due to variations in wave energy. This behavior is characterized by beach erosion and bar decay under high-energy waves and net accretion and bar formation during relatively fair weather conditions. The sand budgets adjustments show that the loss of volume in the winter months is compensated for by accumulation to the beach during summer. This trend suggests that there is a mechanism which controls the beach evolution. The correlation between beach changes and wave energy variations highlights a net relation between them. The results from this in- vestigation state the value of DEMs utilized and demonstrate the efficiency of the 3-D approach employed here to assess the erosion and accretion patterns which would not be visualized using 2-D profiles.展开更多
The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturin...The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturing the details of Earth’s features. This is because they represent only three-dimensional objects in a single texture and do not provide a realistic representation of the real world. Additionally, there is a growing demand for up-to-date and accurate geo-information, particularly in urban areas. To address this challenge, a new technique is proposed in this study that involves integrating remote sensing, Geographic Information System, and Architecture Environment software to generate a highly-detailed three-dimensional model. The method described in this study includes several steps such as acquiring high-resolution satellite imagery, gathering ground truth data, performing radiometric and geometric corrections during image preprocessing, producing a 2D map of the region of interest, constructing a digital surface model by extending the building outlines, and transforming the model into multi-patch layers to create a 3D model for each object individually. The research findings indicate that the digital surface model obtained with comprehensive information is suitable for different purposes, such as environmental research, urban development and expansion planning, and shape recognition tasks.展开更多
In this article,the(1/G')-expansion method,the Bernoulli sub-ordinary differential equation method and the modified Kudryashov method are implemented to construct a variety of novel analytical solutions to the(3+1...In this article,the(1/G')-expansion method,the Bernoulli sub-ordinary differential equation method and the modified Kudryashov method are implemented to construct a variety of novel analytical solutions to the(3+1)-dimensional Boiti-Leon-Manna-Pempinelli model representing the wave propagation through incompressible fluids.The linearization of the wave structure in shallow water necessitates more critical wave capacity conditions than it does in deep water,and the strong nonlinear properties are perceptible.Some novel travelling wave solutions have been observed including solitons,kink,periodic and rational solutions with the aid of the latest computing tools such as Mathematica or Maple.The physical and analytical properties of several families of closed-form solutions or exact solutions and rational form function solutions to the(3+1)-dimensional Boiti-Leon-Manna-Pempinelli model problem are examined using Mathematica.展开更多
The 3D digitalization and documentation of ancient Chinese architecture is challenging because of architectural complexity and structural delicacy.To generate complete and detailed models of this architecture,it is be...The 3D digitalization and documentation of ancient Chinese architecture is challenging because of architectural complexity and structural delicacy.To generate complete and detailed models of this architecture,it is better to acquire,process,and fuse multi-source data instead of single-source data.In this paper,we describe our work on 3D digital preservation of ancient Chinese architecture based on multi source data.We first briefly introduce two surveyed ancient Chinese temples,Foguang Temple and Nanchan Temple.Then,we report the data acquisition equipment we used and the multi-source data we acquired.Finally,we provide an overview of several applications we conducted based on the acquired data,including ground and aerial image fusion,image and LiDAR(light detection and ranging)data fusion,and architectural scene surface reconstruction and semantic modeling.We believe that it is necessary to involve multi-source data for the 3D digital preservation of ancient Chinese architecture,and that the work in this paper will serve as a heuristic guideline for the related research communities.展开更多
With the development of the 3D GIS and the digital basin, it is important for us to deal with the rivers from the 3D space. Compared to traditional forms of 2D GIS, the 3D GIS system brings better user experience for ...With the development of the 3D GIS and the digital basin, it is important for us to deal with the rivers from the 3D space. Compared to traditional forms of 2D GIS, the 3D GIS system brings better user experience for us. After introducing the current development status of the 3D digital river, the paper proposes a novel method for constructing 3D digital river system. It explores the methods in 3D digital river modeling by SketchUp, driving 3D scene by ArcScene and secondary developing by ArcGIS Engine. It discusses the specific issues of 3D river modeling with a river in Nanjing, and sums up a complete 3D modeling of operational process. Finally, that proves the feasibility of the method.展开更多
Three- dimension (3-D) wind-driven currents in the Bohai Sea in both winter and summer are calculated by using a 3- D barotropic steady model, and the results are consistent with observed flow char -acteristics. Based...Three- dimension (3-D) wind-driven currents in the Bohai Sea in both winter and summer are calculated by using a 3- D barotropic steady model, and the results are consistent with observed flow char -acteristics. Based on the results, 3- D characteristics of flow, currents at different depths, compensated flow in the lower layer , long and narrow alongshore current, the area of upwelling and downwelling, main circulation in vertical profile, and the current in Bohai Strait are discussed.展开更多
The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surfac...The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surface based on improved 3D Lacunarity model.Lacunarity curve and its numerical integration are used in this model to improve traditional classification result that different morphological types may share the close value of indexes based on global statistical analysis.Experiments at four test areas with different landform types show that improved 3D Lacunarity model can effectively distinguish different morphological types per texture analysis.Higher sensitivity in distinguishing the tiny differences of texture characteristics of terrain surface shows that the quantification method by 3D Lacu-narity model and its numerical integration presented in this paper could contribute to improving the accuracy of land-form classifications and relative studies.展开更多
Gave a brief introduction to the origin,concepted and hierarchical structure of Digital Mine.As a huge complex system,Digital Mine took data base and model base to- gether as a mine data management system being its co...Gave a brief introduction to the origin,concepted and hierarchical structure of Digital Mine.As a huge complex system,Digital Mine took data base and model base to- gether as a mine data management system being its core,and Digital Mine was com- prised of five subsystems including data obtaining system,integral dispatching system, applied engineering system,data processing system,and data management system.Be- ing a digitally 3D visualized representation and a spatial information infrastructure of an actual mine,Digital Mine had three basic features such as data warehouse,information reference and digital platform.The present developments of Digital Mine in mining industry, research and education were also introduced.Examples were shown for present Digital Mine construction in China.The development trends,the key technologies and the recent construction procedures on Digital Mine were presented.展开更多
This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility...This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility of decreasing the exposure dose in digital breast tomosynthesis (DBT). These two existing algorithms were implemented using a DBT system and experimentally evaluated using contrast-detail (CD) phantom measurements, such as contrast-to-noise ratio (CNR), root mean square error (RMSE), intensity profile, and artifact spread function (ASF), and the results obtained with FBP and SIRT were compared. The potential dose reduction, contrast improvement, quantum noise reduction, and artifact reduction in DBT were evaluated using different exposures and the two reconstruction techniques. The effectiveness of each technique for enhancing the visibility of a CD phantom was quantified with respect to CNR and RMSE, and artifact reduction was quantified with respect to the intensity profile and ASF. SIRT produced reconstructed images with CNR values indicative of high-contrast detection. Image error was smaller in the in-focus plane SIRT images, and artifacts were decreased in these images according to the determined intensity profiles and ASF. These results suggest that when using SIRT, the exposure dose could possibly be decreased to half.展开更多
With the advent of the information age,all walks of life have paid more and more attention to the development and application of digital technology.At the same time,the construction industry,which is a traditionally i...With the advent of the information age,all walks of life have paid more and more attention to the development and application of digital technology.At the same time,the construction industry,which is a traditionally important industry,is not an exception.A series of high-tech digital technologies have been widely used in architectural design and construction,such as BIM technology,3D printing technology,and VR technology.In view of the teaching link of architectural talent training,it is necessary to keep up with the development trend of the digital age,integrate these three kinds of technology into architectural teaching,and impart knowledge to students from planar 2D textbooks to 3D visual digital models,and further transform it from 3D digital to physical perceive or virtual simulation level,and reform teaching methods in all dimensions and in all dimensions to improve teaching effect.In this paper,the feasibility and necessity of integration of the above three architectural digital techniques into the teaching process of"building construction"from the aspects of teaching content,teaching method and teaching evaluation were discussed,and a new teaching model under the background of digital technology was proposed,which has certain teaching reference significance.展开更多
Installation, detection, maintenance, mapping, and management of underground utility assets present challenges to owners, engineers and contractors. Industry-wide practices include the use of geophysical and similar t...Installation, detection, maintenance, mapping, and management of underground utility assets present challenges to owners, engineers and contractors. Industry-wide practices include the use of geophysical and similar technologies to determine depth and location, and 2D as-built plans integrated with GIS databases for information management. The feasibility of incorporating 3D BIM models of the subsurface to replace the 2D plans to improve visualization and data management is examined in this paper. Obtaining an accurate image of the underground infrastructure would help minimize excavation accidents due to equipment-utility collisions and prevent property damage. Further, the inclusion of automated data collection and sharing features realized through BIM technology can enhance operations of smart cities. The research methodology consists of a state-of-the-art review of the current underground utility management systems, combined with statistical analysis of survey responses received from utility providers and one-call centers in the U.S. Three categories of utility practices are identified based on the level of digital technology integration. It is found that a vast majority of utility firms have adopted GIS databases with 2D plans, depth and other asset information, while a smaller percentage of providers have achieved full GIS-BIM in<span style="font-family:Verdana;">tegration, incorporating a wide range of asset data. Future progress on</span><span style="font-family:Verdana;"> broader implementation appears to be constrained by the digital literacy of personnel </span><span style="font-family:Verdana;">and high costs of technology acquisition and application. A three-step frame</span><span style="font-family:Verdana;">work for converting 2D plans to 3D BIM models is also presented and discussed. The process model proposed for this purpose allows the utilization of commercially available software with minimal need for additional coding.</span>展开更多
文摘To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in theelds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling.
文摘Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions for the(3+1)-dimensional Virasoro integrable model,including the interaction solution between a kink and a soliton,the lump-type solution and periodic solutions,have been studied analytically and graphically.
文摘In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent technology education and digital reform,the combination of virtual reality and campus management is the need for innovative thinking and economic and social development,and then better change our learning style and living environment.The construction of the digital campus is based on virtual reality technology,BIM,GIS,and three-dimensional modeling technology to provide an immersive platform for students,promote the integration of virtual reality technology and education,help teachers,students,and parents to understand all kinds of education information and resources,to achieve their interoperability.From the off-campus environment to the school teaching equipment,teachers to teaching quality certification,and learning,to extracurricular entertainment,opening ceremonies to graduation parties,to bring more efficient,convenient,and safe campus life for teachers,students,and staff in school,and break the traditional information restrictions.
文摘With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering.
文摘The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data
文摘With the coming of information age and the development of computer science, digitalization of whole garment is becoming more and more important. The surface of whole garment is sequent and glossy so that it is lack of the texture characteristic which is the key of digital 3D modeling. According to this reason, the structure illumination is steered into a method of this paper. The paper proposes the method by which 3D model of whole garment is created from 2D image sequences directly but not by the common techniques using general CAD model. In the paper the structure illumination is generated by the slide projector and the modeling of whole garment is based on the strict theory of the digital photogrammetry, computer vision and image processing pattern recognition. Because whole garment is lack of the applicable texture for matching, the characteristic texture generated by the structure illumination is added onto the surface of whole garment. After the characteristic texture is extracted from images and is matched well, 3D coordinates of the characteristic texture can be calculated out by the space forward intersection. Then the whole garment model is acquired by connecting all neighhour space points in the TIN and rendering the real texture of whole garment automatically. The 3D modeling method is untouched so that it is nondestructive which is just suitable for the messaline and the clothing. The method of whole garment 3D modeling proposed in the paper is flexible, effective and practical, which is confirmed by the results of the reconstructing experiments.
文摘The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and air temperature field at the 1000 mb level from the European Centre for Medium-Range Weather Forecasts as inputs. The boundary conditions at Bashi Channel and Taiwan Strait are taken from the simulation results of the Kuroshio using the same numerical model with a grid size of 0.5°×0.5° and the results of Cai and Li (1996) as boundary conditions. The computational domain for the present paper is between 100°E and 123°E and between 4.5°N and 27°N. The horizontal resolution is 0.25°×0.25° and the vertical variations of the velocity components are resolved by 6 layers The computed steady flow, temperature and elevation fields are consistent with the corresponding fields observed. In particular, the temperature and elevation fields of the South China Sea Warm Current (SCSWC) have been successfully simulated. The paths of the branch of the Kuroshio entering the South China Sea (SCSBK) through Bashi Channel in winter and summer are discussed It is found that the SCSBK flows southward to the southern SCS from the coast of the Guangdong Province. A portion of the SCSBK returns to the Bashi Channel and subdivides again in deep waters in winter with a branch flows to the south along the coast of the Philippines instead of flowing back to the Pacific In addition, our results confirm the existence of a eastward current to the northeast of Dongsha in summer with the Kuroshio as its source as suggested by Huang et al. Since the value of the eddy viscosity adopted for the simulation of the Kuroshio is on the high side, resulting in a weaker west boundary current in the western Pacific as the boundary conditions for the present simulations, some deviations from the actual situations are expected although the results are in general consistent with observations.
文摘The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional methods for creating digital surface models are insufficient to reflect the details of earth’s features. These models only represent three-dimensional objects in a single texture and fail to offer a realistic depiction of the real world. Furthermore, the need for current and precise geographic information regarding urban areas has been increasing significantly. This study proposes a new technique to address this problem, which involves integrating remote sensing, Geographic Information Systems (GIS), and Architecture Environment software environments to generate a detailed three-dimensional model. The processing of this study starts with: 1) Downloading high-resolution satellite imagery; 2) Collecting ground truth datasets from fieldwork; 3) Imaging nose removing; 4) Generating a Two-dimensional Model to create a digital surface model in GIS using the extracted building outlines; 5) Converting the model into multi-patch layers to construct a 3D model for each object separately. The results show that the 3D model obtained through this method is highly detailed and effective for various applications, including environmental studies, urban development, expansion planning, and shape understanding tasks.
文摘The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the ability of 3-D digital elevation models (DEMs) derived from high accurate data to assess and quantify beach morphodynamics in relation with wave forcing. The methodology and data acquisition are described and consist mainly in the production of interpolated DEMs from which a variety of representations can be made, including as elevation change maps, two-dimensional cross-sections of the beach, calculation of net volume. The results of the analysis highlight seasonal changes in beach morphology due to variations in wave energy. This behavior is characterized by beach erosion and bar decay under high-energy waves and net accretion and bar formation during relatively fair weather conditions. The sand budgets adjustments show that the loss of volume in the winter months is compensated for by accumulation to the beach during summer. This trend suggests that there is a mechanism which controls the beach evolution. The correlation between beach changes and wave energy variations highlights a net relation between them. The results from this in- vestigation state the value of DEMs utilized and demonstrate the efficiency of the 3-D approach employed here to assess the erosion and accretion patterns which would not be visualized using 2-D profiles.
文摘The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturing the details of Earth’s features. This is because they represent only three-dimensional objects in a single texture and do not provide a realistic representation of the real world. Additionally, there is a growing demand for up-to-date and accurate geo-information, particularly in urban areas. To address this challenge, a new technique is proposed in this study that involves integrating remote sensing, Geographic Information System, and Architecture Environment software to generate a highly-detailed three-dimensional model. The method described in this study includes several steps such as acquiring high-resolution satellite imagery, gathering ground truth data, performing radiometric and geometric corrections during image preprocessing, producing a 2D map of the region of interest, constructing a digital surface model by extending the building outlines, and transforming the model into multi-patch layers to create a 3D model for each object individually. The research findings indicate that the digital surface model obtained with comprehensive information is suitable for different purposes, such as environmental research, urban development and expansion planning, and shape recognition tasks.
文摘In this article,the(1/G')-expansion method,the Bernoulli sub-ordinary differential equation method and the modified Kudryashov method are implemented to construct a variety of novel analytical solutions to the(3+1)-dimensional Boiti-Leon-Manna-Pempinelli model representing the wave propagation through incompressible fluids.The linearization of the wave structure in shallow water necessitates more critical wave capacity conditions than it does in deep water,and the strong nonlinear properties are perceptible.Some novel travelling wave solutions have been observed including solitons,kink,periodic and rational solutions with the aid of the latest computing tools such as Mathematica or Maple.The physical and analytical properties of several families of closed-form solutions or exact solutions and rational form function solutions to the(3+1)-dimensional Boiti-Leon-Manna-Pempinelli model problem are examined using Mathematica.
文摘The 3D digitalization and documentation of ancient Chinese architecture is challenging because of architectural complexity and structural delicacy.To generate complete and detailed models of this architecture,it is better to acquire,process,and fuse multi-source data instead of single-source data.In this paper,we describe our work on 3D digital preservation of ancient Chinese architecture based on multi source data.We first briefly introduce two surveyed ancient Chinese temples,Foguang Temple and Nanchan Temple.Then,we report the data acquisition equipment we used and the multi-source data we acquired.Finally,we provide an overview of several applications we conducted based on the acquired data,including ground and aerial image fusion,image and LiDAR(light detection and ranging)data fusion,and architectural scene surface reconstruction and semantic modeling.We believe that it is necessary to involve multi-source data for the 3D digital preservation of ancient Chinese architecture,and that the work in this paper will serve as a heuristic guideline for the related research communities.
基金This work is supported by (1) National Natural Science Foundation of China (61300122) (2) A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (3) Water Science and Technology Project of Jiangsu Province (2013025).
文摘With the development of the 3D GIS and the digital basin, it is important for us to deal with the rivers from the 3D space. Compared to traditional forms of 2D GIS, the 3D GIS system brings better user experience for us. After introducing the current development status of the 3D digital river, the paper proposes a novel method for constructing 3D digital river system. It explores the methods in 3D digital river modeling by SketchUp, driving 3D scene by ArcScene and secondary developing by ArcGIS Engine. It discusses the specific issues of 3D river modeling with a river in Nanjing, and sums up a complete 3D modeling of operational process. Finally, that proves the feasibility of the method.
基金Project supported by the National Natural science Foundation of China
文摘Three- dimension (3-D) wind-driven currents in the Bohai Sea in both winter and summer are calculated by using a 3- D barotropic steady model, and the results are consistent with observed flow char -acteristics. Based on the results, 3- D characteristics of flow, currents at different depths, compensated flow in the lower layer , long and narrow alongshore current, the area of upwelling and downwelling, main circulation in vertical profile, and the current in Bohai Strait are discussed.
基金Under the auspices of National Natural Science Foundation of China (No.40930531,41171320,41001301)
文摘The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surface based on improved 3D Lacunarity model.Lacunarity curve and its numerical integration are used in this model to improve traditional classification result that different morphological types may share the close value of indexes based on global statistical analysis.Experiments at four test areas with different landform types show that improved 3D Lacunarity model can effectively distinguish different morphological types per texture analysis.Higher sensitivity in distinguishing the tiny differences of texture characteristics of terrain surface shows that the quantification method by 3D Lacu-narity model and its numerical integration presented in this paper could contribute to improving the accuracy of land-form classifications and relative studies.
基金the National 863 High-Tech.Program of China(2006AA12Z2162007AA06Z108)the Natural Science Funds of China(50525414,40571137)
文摘Gave a brief introduction to the origin,concepted and hierarchical structure of Digital Mine.As a huge complex system,Digital Mine took data base and model base to- gether as a mine data management system being its core,and Digital Mine was com- prised of five subsystems including data obtaining system,integral dispatching system, applied engineering system,data processing system,and data management system.Be- ing a digitally 3D visualized representation and a spatial information infrastructure of an actual mine,Digital Mine had three basic features such as data warehouse,information reference and digital platform.The present developments of Digital Mine in mining industry, research and education were also introduced.Examples were shown for present Digital Mine construction in China.The development trends,the key technologies and the recent construction procedures on Digital Mine were presented.
文摘This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility of decreasing the exposure dose in digital breast tomosynthesis (DBT). These two existing algorithms were implemented using a DBT system and experimentally evaluated using contrast-detail (CD) phantom measurements, such as contrast-to-noise ratio (CNR), root mean square error (RMSE), intensity profile, and artifact spread function (ASF), and the results obtained with FBP and SIRT were compared. The potential dose reduction, contrast improvement, quantum noise reduction, and artifact reduction in DBT were evaluated using different exposures and the two reconstruction techniques. The effectiveness of each technique for enhancing the visibility of a CD phantom was quantified with respect to CNR and RMSE, and artifact reduction was quantified with respect to the intensity profile and ASF. SIRT produced reconstructed images with CNR values indicative of high-contrast detection. Image error was smaller in the in-focus plane SIRT images, and artifacts were decreased in these images according to the determined intensity profiles and ASF. These results suggest that when using SIRT, the exposure dose could possibly be decreased to half.
基金Supported by the Teaching Reform Project of Jiangxi Normal University(Exploration and Research on the Practical Teaching Reform of Building Construction Course)
文摘With the advent of the information age,all walks of life have paid more and more attention to the development and application of digital technology.At the same time,the construction industry,which is a traditionally important industry,is not an exception.A series of high-tech digital technologies have been widely used in architectural design and construction,such as BIM technology,3D printing technology,and VR technology.In view of the teaching link of architectural talent training,it is necessary to keep up with the development trend of the digital age,integrate these three kinds of technology into architectural teaching,and impart knowledge to students from planar 2D textbooks to 3D visual digital models,and further transform it from 3D digital to physical perceive or virtual simulation level,and reform teaching methods in all dimensions and in all dimensions to improve teaching effect.In this paper,the feasibility and necessity of integration of the above three architectural digital techniques into the teaching process of"building construction"from the aspects of teaching content,teaching method and teaching evaluation were discussed,and a new teaching model under the background of digital technology was proposed,which has certain teaching reference significance.
文摘Installation, detection, maintenance, mapping, and management of underground utility assets present challenges to owners, engineers and contractors. Industry-wide practices include the use of geophysical and similar technologies to determine depth and location, and 2D as-built plans integrated with GIS databases for information management. The feasibility of incorporating 3D BIM models of the subsurface to replace the 2D plans to improve visualization and data management is examined in this paper. Obtaining an accurate image of the underground infrastructure would help minimize excavation accidents due to equipment-utility collisions and prevent property damage. Further, the inclusion of automated data collection and sharing features realized through BIM technology can enhance operations of smart cities. The research methodology consists of a state-of-the-art review of the current underground utility management systems, combined with statistical analysis of survey responses received from utility providers and one-call centers in the U.S. Three categories of utility practices are identified based on the level of digital technology integration. It is found that a vast majority of utility firms have adopted GIS databases with 2D plans, depth and other asset information, while a smaller percentage of providers have achieved full GIS-BIM in<span style="font-family:Verdana;">tegration, incorporating a wide range of asset data. Future progress on</span><span style="font-family:Verdana;"> broader implementation appears to be constrained by the digital literacy of personnel </span><span style="font-family:Verdana;">and high costs of technology acquisition and application. A three-step frame</span><span style="font-family:Verdana;">work for converting 2D plans to 3D BIM models is also presented and discussed. The process model proposed for this purpose allows the utilization of commercially available software with minimal need for additional coding.</span>