期刊文献+
共找到11,819篇文章
< 1 2 250 >
每页显示 20 50 100
Evaluation of Maxillary Dental Arch Widths in Individuals Having Unilateral and Bilateral Cleft Lip and Palate Using Three-Dimensional Digital Models
1
作者 Ege Dogan Abdü +2 位作者 lkadir Iş ik Servet Dogan 《Open Journal of Stomatology》 2019年第7期159-167,共9页
Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had ... Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had been conducted on 80 individuals aged between 14 - 17 years having UCLP and BCLP. 40 of the individuals had UCLP, whereas 40 had BCLP. The maxillary dental models taken from patients before the treatment were scanned using Orthomodel Programme (v.1.01, Orthomodel Inc., Istanbul, Turkey) to obtain 3D imagery. Student’s t-test was used in order to assess the data obtained by using SPSS software version 22.0. Results: In BCLP, the average inter-canine distance was 17.44 ± 1.31 mm, the average inter-molar distance was 36.57 ± 1.12 mm, while inter-canine/inter-molar ratio was 0.47. Whereas in UCLP, it was 25.10 ± 0.63 mm, 42.20 ± 0.53 mm and 0.59. The inter-canine distance in UCLP was found to be large enough to be statistically significant (p 0.05), even though there were differences in inter-molar widths. Conclusion: For the stable orthodontic treatment results, one of the most important points is arch form and widths to be coherent with each other. In our study, the increase of inter-canine distance seen in UCLP indicates that in the cleft region, the maxillary arch is inclined over to the back, while the same situation in BCLP suggests that the maxillary segments are collapsed inside. The difference in the arch is highly affected by the primary surgical treatment. 展开更多
关键词 UNILATERAL CLEFT LIP and PALATE Bilateral CLEFT LIP and PALATE three-dimensional digital models
下载PDF
From Digital Human Modeling to Human Digital Twin: Framework and Perspectives in Human Factors
2
作者 Qiqi He Li Li +5 位作者 Dai Li Tao Peng Xiangying Zhang Yincheng Cai Xujun Zhang Renzhong Tang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第1期1-14,共14页
The human digital twin(HDT)emerges as a promising human-centric technology in Industry 5.0,but challenges remain in human modeling and simulation.Digital human modeling(DHM)provides solutions for modeling and simulati... The human digital twin(HDT)emerges as a promising human-centric technology in Industry 5.0,but challenges remain in human modeling and simulation.Digital human modeling(DHM)provides solutions for modeling and simulating human physical and cognitive aspects to support ergonomic analysis.However,it has limitations in real-time data usage,personalized services,and timely interaction.The emerging HDT concept offers new possibilities by integrating multi-source data and artificial intelligence for continuous monitoring and assessment.Hence,this paper reviews the evolution from DHM to HDT and proposes a unified HDT framework from a human factors perspective.The framework comprises the physical twin,the virtual twin,and the linkage between these two.The virtual twin integrates human modeling and AI engines to enable model-data-hybrid-enabled simulation.HDT can potentially upgrade traditional ergonomic methods to intelligent services through real-time analysis,timely feedback,and bidirectional interactions.Finally,the future perspectives of HDT for industrial applications as well as technical and social challenges are discussed.In general,this study outlines a human factors perspective on HDT for the first time,which is useful for cross-disciplinary research and human factors innovation to enhance the development of HDT in industry. 展开更多
关键词 Human digital twin digital human modeling Human factors Human-centric technology
下载PDF
Research on the Audio Publishing of Classical Books Based on the Theory of Business Model Canvas: Taking Romance of the Three Kingdoms in Digital Audio Platforms as an Example
3
作者 Ding Qin Liu Mengzhi 《Contemporary Social Sciences》 2024年第1期58-74,共17页
Visual media have dominated sensory communications for decades,and the resulting“visual hegemony”leads to the call for the“auditory return”in order to achieve a holistic balance in cultural acceptance.Romance of t... Visual media have dominated sensory communications for decades,and the resulting“visual hegemony”leads to the call for the“auditory return”in order to achieve a holistic balance in cultural acceptance.Romance of the Three Kingdoms,a classic literary work in China,has received significant attention and promotion from leading audio platforms.However,the commercialization of digital audio publishing faces unprecedented challenges due to the mismatch between the dissemination of long-form content on digital audio platforms and the current trend of short and fast information reception.Drawing on the Business Model Canvas Theory and taking Romance of the Three Kingdoms as the main focus of analysis,this paper argues that the construction of a business model for the audio publishing of classical books should start from three aspects:the user evaluation of digital audio platforms,the establishment of value propositions based on the“creative transformation and innovative development”principle,and the improvement of the audio publishing infrastructure to ensure the healthy operation and development of the digital audio platforms and consequently improve their current state of development and expand the boundaries of cultural heritage. 展开更多
关键词 Romance of the Three Kingdoms audio publishing Business model Canvas digital audio platforms
下载PDF
Three-Dimensional TIN Algorithm for Digital Terrain Modeling 被引量:6
4
作者 ZHU Qing ZHANG Yeting LI Fengchun 《Geo-Spatial Information Science》 2008年第2期79-85,共7页
The problem of taking an unorganized point cloud in 3D space and fitting a polyhedral surface to those points is both important and difficult. Aiming at increasing applications of full three dimensional digital terrai... The problem of taking an unorganized point cloud in 3D space and fitting a polyhedral surface to those points is both important and difficult. Aiming at increasing applications of full three dimensional digital terrain surface modeling, a new algorithm for the automatic generation of three dimensional triangulated irregular network from a point cloud is pro- posed. Based on the local topological consistency test, a combined algorithm of constrained 3D Delaunay triangulation and region-growing is extended to ensure topologically correct reconstruction. This paper also introduced an efficient neighbor- ing triangle location method by making full use of the surface normal information. Experimental results prove that this algo- rithm can efficiently obtain the most reasonable reconstructed mesh surface with arbitrary topology, wherein the automati- cally reconstructed surface has only small topological difference from the true surface. This algorithm has potential applica- tions to virtual environments, computer vision, and so on. 展开更多
关键词 三角形 三维网络 测绘数据库 地球科学
下载PDF
Comprehensive Survey of the Landscape of Digital Twin Technologies and Their Diverse Applications
5
作者 Haiyu Chen Haijian Shao +2 位作者 Xing Deng Lijuan Wang Xia Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期125-165,共41页
The concept of the digital twin,also known colloquially as the DT,is a fundamental principle within Industry 4.0 framework.In recent years,the concept of digital siblings has generated considerable academic and practi... The concept of the digital twin,also known colloquially as the DT,is a fundamental principle within Industry 4.0 framework.In recent years,the concept of digital siblings has generated considerable academic and practical interest.However,academia and industry have used a variety of interpretations,and the scientific literature lacks a unified and consistent definition of this term.The purpose of this study is to systematically examine the definitional landscape of the digital twin concept as outlined in scholarly literature,beginning with its origins in the aerospace domain and extending to its contemporary interpretations in the manufacturing industry.Notably,this investigationwill focus on the research conducted on Industry 4.0 and smartmanufacturing,elucidating the diverse applications of digital twins in fields including aerospace,intelligentmanufacturing,intelligent transportation,and intelligent cities,among others. 展开更多
关键词 digital twins Industry 4.0 smart manufacturing digital thread modeling simulation
下载PDF
A Dual Closed-Loop Digital Twin Construction Method for Optimizing the Copper Disc Casting Process
6
作者 Zhaohui Jiang Chuan Xu +3 位作者 Jinshi Liu Weichao Luo Zhiwen Chen Weihua Gui 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期581-594,共14页
The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casti... The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient production.However,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC optimization.To this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting process.Furthermore,a CPMC optimization model is proposed for the first time.On top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting process.Finally,a case study is carried out based on the proposed methods in the industrial field. 展开更多
关键词 Copper disc casting machine digital twin(DT) mechanism modeling SELF-OPTIMIZATION
下载PDF
Control Strategies for Digital Twin Systems
7
作者 Guo-Ping Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第1期170-180,共11页
With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies ... With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical applications.To make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples. 展开更多
关键词 digital twin control systems fault tolerant control model tracking performance prediction performance retention
下载PDF
Research on the Digital Economy's Impact on China's Economic Growth:Based on the Variations in Urbanization Levels Across China's Eastern,Central,and Western Regions and Sectoral Heterogeneity
8
作者 Qiu Jin Yan Hong 《Contemporary Social Sciences》 2024年第3期27-44,共18页
This paper uses inter-provincial panel data from 2011 to 2017,a linear regression model,and a threshold model to conduct empirical analyses of the impact of the digital economy on China's overall economic growth a... This paper uses inter-provincial panel data from 2011 to 2017,a linear regression model,and a threshold model to conduct empirical analyses of the impact of the digital economy on China's overall economic growth and the three main sectors of industry.The paper then investigates the impact and effects the digital economy has had on the economic growth of the three main sectors of industry in China's eastern,central,and western regions.Finally,the paper investigates the most significant differences among the various regions and the threshold effects of urbanization levels on the relationship between the digital economy and economic growth.The findings indicate a significantly positive correlation between the digital economy and regional economic growth.Moreover,geographical factors notably influence this correlation.The digital economy exerts a positive effect on all sectors of industry.It may not substantially impact industrial development in regions with highly developed infrastructure.Regarding the other regions,the digital economy exhibits varying degrees of impact due to the differences in the specific indicators.The conclusion drawn by the threshold model is that the magnitude of the threshold effect correlates with geographic factors.No threshold effect was observed in the eastern region,while the threshold effect occurred in the central region when the urbanization levels for the provinces were below 0.6645.Similarly,the threshold effect was noted in the western region when the urbanization level was below 0.3931.Considering all of this,the study also offers policy recommendations that will help balance the regional development of digital economies,accelerate the digital transformation of traditional industries,enhance digital infrastructure construction,refine the formulation and implementation of data policy,and establish relevant incentive mechanisms. 展开更多
关键词 digital economy economic growth regional differences urbanization level threshold models
下载PDF
How R&D investment promotes green technology innovation in the context of digitalization?-An empirical analysis based on provincial panel data
9
作者 LIU Jie LI Zhi-hui WEI Fang-xin 《Ecological Economy》 2024年第1期39-52,共14页
Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincia... Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincial panel data from 2016 to 2019 to study the impact mechanism of R&D investment on green technology innovation,and introduces the level of digitization,using the panel threshold model to discuss its role in the impact mechanism of R&D investment on green technology innovation.The study found that when the level of digitalization in a region is low,increasing R&D investment does not necessarily improve the ability of green technology innovation;when the level of digitalization is relatively high,R&D investment has a positive role in promoting green technology innovation.Therefore,it is necessary to improve policies to encourage enterprises to increase investment in research and development;at the same time,it is necessary to promote the coordinated development of digital foundation,digital investment,digital literacy,digital economy and digital application,and promote the deep integration of digitalization and green technology innovation. 展开更多
关键词 green technology innovation R&D investment digital level panel model
下载PDF
Generative Adversarial Networks Based Digital Twin Channel Modeling for Intelligent Communication Networks 被引量:1
10
作者 Yuxin Zhang Ruisi He +5 位作者 Bo Ai Mi Yang Ruifeng Chen Chenlong Wang Zhengyu Zhang Zhangdui Zhong 《China Communications》 SCIE CSCD 2023年第8期32-43,共12页
Integration of digital twin(DT)and wireless channel provides new solution of channel modeling and simulation,and can assist to design,optimize and evaluate intelligent wireless communication system and networks.With D... Integration of digital twin(DT)and wireless channel provides new solution of channel modeling and simulation,and can assist to design,optimize and evaluate intelligent wireless communication system and networks.With DT channel modeling,the generated channel data can be closer to realistic channel measurements without requiring a prior channel model,and amount of channel data can be significantly increased.Artificial intelligence(AI)based modeling approach shows outstanding performance to solve such problems.In this work,a channel modeling method based on generative adversarial networks is proposed for DT channel,which can generate identical statistical distribution with measured channel.Model validation is conducted by comparing DT channel characteristics with measurements,and results show that DT channel leads to fairly good agreement with measured channel.Finally,a link-layer simulation is implemented based on DT channel.It is found that the proposed DT channel model can be well used to conduct link-layer simulation and its performance is comparable to using measurement data.The observations and results can facilitate the development of DT channel modeling and provide new thoughts for DT channel applications,as well as improving the performance and reliability of intelligent communication networking. 展开更多
关键词 digital twin channel modeling generative adversarial networks intelligent communication networking
下载PDF
Construction of Intelligent Recommendation Retrieval Model of FuJian Intangible Cultural Heritage Digital Archives Resources 被引量:1
11
作者 Xueqing Liao 《Intelligent Automation & Soft Computing》 SCIE 2023年第7期677-690,共14页
In order to improve the consistency between the recommended retrieval results and user needs,improve the recommendation efficiency,and reduce the average absolute deviation of resource retrieval,a design method of int... In order to improve the consistency between the recommended retrieval results and user needs,improve the recommendation efficiency,and reduce the average absolute deviation of resource retrieval,a design method of intelligent recommendation retrieval model for Fujian intangible cultural heritage digital archive resources based on knowledge atlas is proposed.The TG-LDA(Tag-granularity LDA)model is proposed on the basis of the standard LDA(Linear Discriminant Analysis)model.The model is used to mine archive resource topics.The Pearson correlation coefficient is used to measure the relevance between topics.Based on the measurement results,the FastText deep learning model is used to achieve archive resource classification.According to the classification results,TF-IDF(term frequency–inverse document frequency)algorithm is used to calculate the weight of resource retrieval keywords to achieve resource retrieval,and a recommendation model of intangible cultural heritage digital archives resources is built through the knowledge map to achieve comprehensive and personalized recommendation of resources.The experimental results show that the recommendation and retrieval results of the proposed method are more in line with users’needs,can provide users with personalized digital archive resources,and the average absolute deviation of resource retrieval is low,the recommendation efficiency is high,and the utilization effect of archive resources is effectively improved. 展开更多
关键词 Knowledge map intangible cultural heritage digital archives intelligent recommendation SEARCH TG-LDA model fasttext model
下载PDF
A Study of the Impact of the Digital Economy on the Efficiency of Urban Green Economy--Based on the Yangtze River Delta City Cluster
12
作者 LU Yang MIN Tianwei 《Management Studies》 2024年第1期1-8,共8页
This paper adopts the non-expected output-super-efficiency SBM(Slacks-Based Model)model and principal component analysis to calculate the green economy efficiency and the digital economy level of 27 prefecture-level c... This paper adopts the non-expected output-super-efficiency SBM(Slacks-Based Model)model and principal component analysis to calculate the green economy efficiency and the digital economy level of 27 prefecture-level cities in China’s Yangtze River Delta urban agglomeration between 2011 and 2019,respectively,and examines the impact of the digital economy on the green economy efficiency by using benchmark regression and mechanism analysis.The findings show that,first,the digital economy has a significant contribution to the green economic efficiency of cities,and this conclusion still holds after robustness tests such as replacing explanatory and interpreted variables and introducing province-fixed effects.Second,through the mechanism test,it is found that the digital economy can indirectly promote urban green economic efficiency through the positive mechanism effect of promoting industrial structure upgrading. 展开更多
关键词 digital economy urban green economy efficiency undesired output-super-efficiency SBM model
下载PDF
Review of Digital Campus Construction Led by Virtual Reality Technology
13
作者 Jiaxuan Tang Yalin Lin Xinmin Hu 《Journal of Electronic Research and Application》 2024年第3期148-154,共7页
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
关键词 digital campus Virtual reality technology BIM GIS 3D modeling
下载PDF
Exploring Alternatives to Create Digital Twins from and for Process Simulation
14
作者 Jaime Barbero-Sánchez Alicia Megía-Ortega +1 位作者 Víctor R.Ferro Jose-Luis Valverde 《Journal of Computer Science Research》 2024年第1期16-30,共15页
In this work,Digital Twins based on Neural Networks for the steady state production of styrene were generated.Thus,both the Aspen Technology AI Model Builder(alternative 1)and a homemade MS Excel VBA code connected to... In this work,Digital Twins based on Neural Networks for the steady state production of styrene were generated.Thus,both the Aspen Technology AI Model Builder(alternative 1)and a homemade MS Excel VBA code connected to Aspen HYSYS and Aspen Plus(alternative 2)were used with this same aim.The raw data used for generating the Digital Twins were obtained from process simulations using Aspen HYSYS and/or Aspen Plus,which were connected through a recycle-like stream via automation for solving the entire simulation flowsheet.Aspen HYSYS was used for solving the pre-heating,reaction,and stabilization sections of the process whereas Aspen Plus ensured the computing of the separation and purification columns.Both alternatives led to an excellent prediction showing the capability of creating Digital Twins from and for process simulation. 展开更多
关键词 digital Twin Aspen Hybrid model Builder Aspen HYSYS Aspen Plus Automation MS Excel-VBA
下载PDF
Study of the geomagnetic field's regional gradients in Chinese continent using three-dimensional surface Spline model
15
作者 Yan Feng YiJun Li +3 位作者 JinYan Zhang Shuang Liu Abbas Nasir Ya Huang 《Earth and Planetary Physics》 EI CSCD 2023年第1期74-83,共10页
We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the p... We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the precision of the model,we considered the data gap between the ground and satellite data.We compared and analyzed the results of the Taylor polynomial,surface Spline,and CHAOS-6(the CHAMP,?rsted and SAC-C model of Earth’s magnetic field)gradient models.Results showed that the gradients in the south-north and east-west directions of the four models were consistent.The 3DSS model was able to express not only gradients at different altitudes,but also average gradients inside the research area.The two Spline models were able to capture more information on gradient anomalies than were the fitted models.Strong local anomalies were observed in northern Xinjiang,Beijing,and the junction area between Jiangsu and Zhejiang,and the total intensity F decreased whereas the altitude increased.The gradient decreased by 21.69%in the south-north direction and increased by 11.78%in the east-west direction.In addition,the altitude gradient turned from negative to positive while the altitude increased.The Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory. 展开更多
关键词 geomagnetic field main field gradients regional model three-dimensional modeling
下载PDF
Can preoperative planning using IRIS™three-dimensional anatomical virtual models predict operative findings during robot-assisted partial nephrectomy?
16
作者 Ahmed Ghazi Nitin Sharma +6 位作者 Ahmed Radwan Hani Rashid Thomas Osinski Thomas Frye William Tabayoyong Jonathan Bloom Jean Joseph 《Asian Journal of Urology》 CSCD 2023年第4期431-439,共9页
Objective To evaluate the predictive validity of IRIS™(Intuitive Surgical®,Sunnyvale,CA,USA)as a planning tool for robot-assisted partial nephrectomy(RAPN)by assessing the degree of overlap with intraoperative ex... Objective To evaluate the predictive validity of IRIS™(Intuitive Surgical®,Sunnyvale,CA,USA)as a planning tool for robot-assisted partial nephrectomy(RAPN)by assessing the degree of overlap with intraoperative execution.Methods Thirty-one patients scheduled for RAPN by four experienced urologists were enrolled in a prospective study.Prior to surgery,urologists reviewed the IRIS™three-dimensional model on an iphone Operating System(iOS)app and completed a questionnaire outlining their surgical plan including surgical approach,and ischemia technique as well as confidence in executing this plan.Postoperatively,questionnaires assessing the procedural approach,clinical utility,efficiency,and effectiveness of IRIS™were completed.The degree of overlap between the preoperative and intraoperative questionnaires and between the planned approach and actual execution of the procedure was analyzed.Questionnaires were answered on a 5-point Likert scale and scores of 4 or greater were considered positive.Results Mean age was 65.1 years with a mean tumor size of 27.7 mm(interquartile range 17.5-44.0 mm).Hilar tumors consisted of 32.3%;48.4%of patients had R.E.N.A.L.nephrometry scores of 7-9.On preoperative questionnaires,the surgeons reported that in 67.7%cases they were confident that they can perform the procedure successfully,and on intraoperative questionnaires,the surgeons reported that in 96.8%cases IRIS™helped achieve good spatial sensation of the anatomy.There was a high degree of overlap between preoperative and intraoperative questionnaires for the surgical approach,interpreting anatomical details and clinical utility.When comparing plans for selective or off-clamp,the preoperative plan was executed in 90.0%of cases intraoperatively.Conclusion A high degree of overlap between the preoperative surgical approach and intraoperative RAPN execution was found using IRIS™.This is the first study to evaluate the predictive accuracy of IRIS™during RAPN by comparing preoperative plan and intraoperative execution. 展开更多
关键词 Renal cancer PATIENT-SPECIFIC three-dimensional virtual model Imaging Partial nephrectomy Robotics
下载PDF
Modeling Methods of 3D Model in Digital Twins
17
作者 Ruijun Liu Haisheng Li Zhihan Lv 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第8期985-1022,共38页
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 the􀀀elds 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
关键词 digital twins 3D modeling smart manufacturing smart city smart buildings
下载PDF
Three-Dimensional Analytical Modeling of Axial-Flux Permanent Magnet Drivers
18
作者 Wenhui Li Dazhi Wang +3 位作者 Shuo Cao Deshan Kong Sihan Wang Zhong Hua 《Computers, Materials & Continua》 SCIE EI 2023年第4期259-276,共18页
In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare co... In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare comprehensively considered, and the governing equations are solved bysimplifying the boundary conditions. The axial magnetization of the sectorshapedpermanent magnets is accurately described in an algebraic form bythe parameters, which makes the physical meaning more explicit than thepurely mathematical expression in general series forms. The parameters of theBessel function are determined simply and the magnetic field distribution ofpermanent magnets and the air-gap is solved. Furthermore, the field solutionsare completely analytical, which provides convenience and satisfactoryaccuracy for modeling a series of electromagnetic performance parameters,such as the axial electromagnetic force density, axial electromagnetic force,and electromagnetic torque. The correctness and accuracy of the analyticalmodels are fully verified by three-dimensional finite element simulations and a15 kW prototype and the results of calculations, simulations, and experimentsunder three methods are highly consistent. The influence of several designparameters on magnetic field distribution and performance is studied and discussed.The results indicate that the modeling method proposed in this papercan calculate the magnetic field distribution and performance accurately andrapidly, which affords an important reference for the design and optimizationof axial-flux permanent magnet drivers. 展开更多
关键词 three-dimensional analytical modeling cylindrical coordinates magnetic field distribution parameter sensitivity analysis performance measurement
下载PDF
Impact of Digital Economy Development on Industrial Structure Upgrading-An Empirical Analysis Based on PVAR Model
19
作者 Junjie HU Yang LU 《Management Studies》 2023年第2期84-92,共9页
Based on the panel data of 248 prefecture-level cities in China from 2011-2021,a PVAR model is constructed to empirically compare and analyze the impact of national and regional digital economy development on industri... Based on the panel data of 248 prefecture-level cities in China from 2011-2021,a PVAR model is constructed to empirically compare and analyze the impact of national and regional digital economy development on industrial structure upgrading.The results show that:from the national level,the development of the digital economy can significantly promote the upgrading of industrial structure,the degree of influence rises and then decreases,and lasts longer;the upgrading of industrial structure also affects the development of the digital economy,and the influence changes from negative to positive;there is a long-term,continuous,and significant dynamic effect between the digital economy and the transformation and upgrading of industrial structure,and the two affect each other.From the perspective of each region,the impact of digital economy development on industrial structure upgrading is somewhat different.The industrial structure in the western region is the most sensitive to the digital economy changes,followed by the eastern region and the weakest in the central region.However,the industrial structure upgrading in all regions is significantly and positively influenced by the development of the digital economy. 展开更多
关键词 digital economy industrial structure upgrading PVAR model
下载PDF
Optical encryption of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography 被引量:2
20
作者 王莹 刘琦 +1 位作者 王君 王琼华 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期253-259,共7页
We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the ... We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance. 展开更多
关键词 multiple three-dimensional objects encryption single-pixel digital holography phase-shifting in- terference compressive sensing
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部