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Computational Quantification of Map Projection Distortion by Fractal Dimension of Coastlines
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作者 Franklin Lee 《Journal of Applied Mathematics and Physics》 2024年第5期1890-1903,共14页
Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short w... Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections. 展开更多
关键词 Map projection Distortion COASTLINE fractal Dimension CARTOGRAPHY Geographic Information Systems
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Projection Theory and Research of Ancient Chinese Graphics
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作者 LIU Ke-ming LIU Li-shi 《Computer Aided Drafting,Design and Manufacturing》 2015年第1期7-15,共9页
Demonstrating the approach to protract the figure of three-dimensional graphs with geometrical forms in two-dimensional planes, graphics is a basic technical discipline of examining protracting engineering drawings us... Demonstrating the approach to protract the figure of three-dimensional graphs with geometrical forms in two-dimensional planes, graphics is a basic technical discipline of examining protracting engineering drawings using the method of projection and addressing issues on space geometry as well as its theory and approach. Graphics is also a kind of semiotic system of writing. China boasts of rich tradition of graphics with amazing architectural drawings in Pre-Qin period, booming theories of graphics in Wei and Jin Dynasties, refined protracted drawings in Song and Yuan Dynasties, and graphics being regarded as important instruments in Ming and Qing Dynasties when thorough apprehension were pursued in order to seek the practice of administration. It not only forms the basis for modem and contemporary graphics in China, but also shapes the future development of graphics. 展开更多
关键词 ancient Chinese graphics projection theory focus perspective cavalier perspective
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Discriminating between photorealistic computer graphics and natural images using fractal geometry 被引量:6
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作者 PAN Feng CHEN JiongBin HUANG JiWu 《Science in China(Series F)》 2009年第2期329-337,共9页
Rendering technology in computer graphics (CG) is now capable of producing highly photorealistic images, giving rise to the problem of how to identify CG images from natural images. Some methods were proposed to sol... Rendering technology in computer graphics (CG) is now capable of producing highly photorealistic images, giving rise to the problem of how to identify CG images from natural images. Some methods were proposed to solve this problem. In this paper, we give a novel method from a new point of view of image perception. Although the photorealistic CG images are very similar to natural images, they are surrealistic and smoother than natural images, thus leading to the difference in perception. A pert of features are derived from fractal dimension to capture the difference in color perception between CG images and natural images, and several generalized dimensions are used as the rest features to capture difference in coarseness. The effect of these features is verified by experiments. The average accuracy is over 91.2%. 展开更多
关键词 image forensics computer graphics natural image fractal image authentication
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APPLICATION OF COMPUTER GRAPHICS IN MARTENSITIC TRANSFORMATION 被引量:3
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作者 Zhou JianqiSouthern Naval Unit of Institute of Naval Technical Equipment in Zhanjiang Manuscript received 18 April, 1994 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1994年第2期103-106,共4页
This paper discuss the stereographic method of martensitic transformation (MT)in the view of computer graphics (CG) and programs are programmed to realize this method. Habit plane resulting from the programs agrees wi... This paper discuss the stereographic method of martensitic transformation (MT)in the view of computer graphics (CG) and programs are programmed to realize this method. Habit plane resulting from the programs agrees with that of numerical analysis in terms of the lattice parameters of austenite and martensite and shear mechanism supposed in Fe-22%Ni-0.8%C alloy, so does orientation relationships. 展开更多
关键词 stereograpllic projection martensitic transformation computer graphics
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SELF-DEPENDENT LOCALITY PRESERVING PROJECTION WITH TRANSFORMED SPACE-ORIENTED NEIGHBORHOOD GRAPH
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作者 乔立山 张丽梅 孙忠贵 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第3期261-268,共8页
Locality preserving projection (LPP) is a typical and popular dimensionality reduction (DR) method,and it can potentially find discriminative projection directions by preserving the local geometric structure in da... Locality preserving projection (LPP) is a typical and popular dimensionality reduction (DR) method,and it can potentially find discriminative projection directions by preserving the local geometric structure in data. However,LPP is based on the neighborhood graph artificially constructed from the original data,and the performance of LPP relies on how well the nearest neighbor criterion work in the original space. To address this issue,a novel DR algorithm,called the self-dependent LPP (sdLPP) is proposed. And it is based on the fact that the nearest neighbor criterion usually achieves better performance in LPP transformed space than that in the original space. Firstly,LPP is performed based on the typical neighborhood graph; then,a new neighborhood graph is constructed in LPP transformed space and repeats LPP. Furthermore,a new criterion,called the improved Laplacian score,is developed as an empirical reference for the discriminative power and the iterative termination. Finally,the feasibility and the effectiveness of the method are verified by several publicly available UCI and face data sets with promising results. 展开更多
关键词 graphic methods Laplacian transforms unsupervised learning dimensionality reduction locality preserving projection
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Сomputational Experience Optimization of Colors in Complex Fractal Images in Carpet Design Using the Simplex Method
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作者 Fakhriddin Nuraliev Oybek Narzulloyev Saida Tastanova 《Journal of Computer Science Research》 2022年第4期7-14,共8页
This article proposes a new approach based on linear programming optimization to solve the problem of determining the color of a complex fractal carpet pattern.The principle is aimed at finding suitable dyes for mixin... This article proposes a new approach based on linear programming optimization to solve the problem of determining the color of a complex fractal carpet pattern.The principle is aimed at finding suitable dyes for mixing and their exact concentrations,which,when applied correctly,gives the desired color.The objective function and all constraints of the model are expressed linearly according to the solution variables.Carpet design has become an emerging technological field known for its creativity,science and technology.Many carpet design concepts have been analyzed in terms of color,contrast,brightness,as well as other mathematical concepts such as geometric changes and formulas.These concepts represent a common process in the carpet industry.This article discusses the use of complex fractal images in carpet design and simplex optimization in color selection. 展开更多
关键词 fractal Optimization methods Simplex-method Geometric transformations Computer graphics Pascal’s triangle
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Instantaneous solitons and fractal solitons for a (2+1)-dimensional nonlinear system 被引量:2
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作者 潘震环 马松华 方建平 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期34-39,共6页
By an improved projective equation approach and a linear variable separation approach, a new family of exact solutions of the (2+1)-dimensional Broek-Kaup system is derived. Based on the derived solitary wave solut... By an improved projective equation approach and a linear variable separation approach, a new family of exact solutions of the (2+1)-dimensional Broek-Kaup system is derived. Based on the derived solitary wave solution and by selecting appropriate functions, some novel localized excitations such as instantaneous solitons and fractal solitons are investigated. 展开更多
关键词 improved projective equation approach Broek-Kaup system exact solutions instanta-neous solitons and fractal solitons
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Vertical derivative conversion of irregular-range potential fi eld data based on improved projection onto convex sets method 被引量:1
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作者 Zeng Xiao-Niu Li Xi-Hai +2 位作者 Yu Xiao-Tong Liu Ji-Hao Liu Dai-Zhi 《Applied Geophysics》 SCIE CSCD 2021年第4期461-472,592,共13页
Gravity and magnetic exploration areas are usually irregular,and there is some data defi ciency.Missing data must be interpolated before the vertical derivative conversion in the wavenumber domain.Meanwhile,for improv... Gravity and magnetic exploration areas are usually irregular,and there is some data defi ciency.Missing data must be interpolated before the vertical derivative conversion in the wavenumber domain.Meanwhile,for improved processing precision,the data need to be edge-padded to the length required by the fast Fourier transform algorithm.For conventional vertical derivative conversion of potential fi eld data(PFD),only vertical derivative conversion is considered,or interpolation,border padding,and vertical derivative conversion are executed independently.In this paper,these three steps are considered uniformly,and a vertical derivative conversion method for irregular-range PFD based on an improved projection onto convex sets method is proposed.The cutoff wavenumber of the filter used in the proposed method is determined by fractal model fi tting of the radial average power spectrum(RAPS)of the potential fi eld.Theoretical gravity models and real aeromagnetic data show the following:(1)The fitting of the RAPS with a fractal model can separate useful signals and noise reasonably.(2)The proposed iterative method has a clear physical sense,and its interpolation,border padding error,and running time are much smaller than those of the conventional kriging and minimum curvature methods. 展开更多
关键词 Potential fi eld vertical derivative projection onto convex sets fractal model
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Mathematics and Computer Graphic Design Arts
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作者 Xu Yafei(徐亚非) 《Journal of Donghua University(English Edition)》 EI CAS 2001年第1期127-129,共3页
The relationship between arts and mathematics is very close, computer graphic design is based on digital methodology. The paper reveals the mathematical backgrounds behind graphic design by the example of computer-aid... The relationship between arts and mathematics is very close, computer graphic design is based on digital methodology. The paper reveals the mathematical backgrounds behind graphic design by the example of computer-aided cubic modeling and mathematical exchange methodology. Furthermore, one can get incredible artistic effects if computer graphic designers pay more attention to the probability and use probable numbers and fractal operation in their design activities.Finally, the author also discusses the bidirections between arts and mathematics. 展开更多
关键词 computer graphic design ARTS and mathematics cubic modeling MATHEMATICS operation fractal theory application design evaluation.
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Fractal Structures and Chaotic Behaviors in a (2+1)-Dimensional Nonlinear System
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作者 马松华 张龄月 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第6期1117-1121,共5页
With a new projective equation, a series of solutions of the (2-J-1)-dimensional dispersive long-water wave system (LWW) is derived. Based on the derived solitary wave solution, we obtain some special fractal loca... With a new projective equation, a series of solutions of the (2-J-1)-dimensional dispersive long-water wave system (LWW) is derived. Based on the derived solitary wave solution, we obtain some special fractal localized structures and chaotic patterns. 展开更多
关键词 new projective equation (2+1)-dimensional LWW system fractal structures chaotic behaviors
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FRACTAL图形生成系统
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作者 许道云 周沛 聂堂钊 《贵州大学学报(自然科学版)》 1994年第3期159-166,共8页
本文就自平方复函数z→z^2+c生成的Fractal在计算机上的处理进行了广泛讨论.形成了一个完整的Fractal图形生成系统.系统由Microsoft c 6.0编制而成,可对形如Z_(n+1)=f(z_n)的复变换进行作图分析.
关键词 PRACTAL 计算机图形学
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云南永胜古滑坡堰塞湖沉积物粒度多重分形特征及其指标适用研究
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作者 张宇 徐宗恒 +1 位作者 查玲珑 陈云英 《地理科学》 CSSCI CSCD 北大核心 2024年第9期1666-1675,共10页
本文以云南永胜县下院滑坡堰塞湖沉积物为研究对象,依据粒度测试结果采用传统粒度指标与分形理论相结合的方式对其沉积环境进行系统化研究,探讨各传统指标在堰塞湖沉积解析中的适用性,探索多重分形理论在沉积学中的应用价值。研究结果表... 本文以云南永胜县下院滑坡堰塞湖沉积物为研究对象,依据粒度测试结果采用传统粒度指标与分形理论相结合的方式对其沉积环境进行系统化研究,探讨各传统指标在堰塞湖沉积解析中的适用性,探索多重分形理论在沉积学中的应用价值。研究结果表明:①堰塞湖沉积物粒度统计参数明显不同于其他环境下的沉积物,具有河湖相沉积独特的分布曲线形式、分选状态和分形特征。优势粒级在分形计算中起主导地位,全局分形维数与分选系数有着良好的对应关系。不同的分形维数对应着不同的堰塞湖沉积条件,分形维数在堰塞湖粒度解析中有着很好的运用前景;②多重分形结果显示2种不同时期的堰塞湖沉积物均以高聚集度组分为主体,表明粒径分布集中,反映出堰塞湖沉积过程中水动力的稳定性,沉积来源的唯一性,进一步证明了该堰塞湖曾长期存在。细粒组沉积粒径分布范围较窄,分布相对集中,优势粒组多但单个含量低,尾端含量低,内部分异较大;粗粒组分布呈局部集中整体分散的趋势,高聚集度粒组数量少但含量高,低聚集度粒组数量多但单个含量低,呈现中间高,四周低的特点。③多重分形分析表明Δα、Δf在沉积物粒度分析中能够解析粒组内部分布特征,具有传统指标不可替代的作用,D_(0)和D_(1)两者结合可作为沉积环境解析的替代指标,与其他q阶多重分形联合可进一步作为堰塞湖解析指标,而D_(1)/D_(0)和D2则存在一定局限。 展开更多
关键词 堰塞湖沉积 粒度特征 图解法 分形维数 多重分形谱维数
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基于GPU和角正交投影视图的多视角投影全息图
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作者 曹雪梅 张春晓 +4 位作者 管明祥 夏林中 郭丽丽 苗玉虎 曹士平 《深圳大学学报(理工版)》 CAS CSCD 北大核心 2024年第5期536-541,共6页
针对多视角投影全息图生成速度慢的问题,提出一种基于计算机图形处理单元(graphics processing unit,GPU)的多视角投影计算全息图合成方法.获取多个角正交投影视图,充分利用GPU强大的并行计算能力,同时计算多幅投影视图对全息图的作用,... 针对多视角投影全息图生成速度慢的问题,提出一种基于计算机图形处理单元(graphics processing unit,GPU)的多视角投影计算全息图合成方法.获取多个角正交投影视图,充分利用GPU强大的并行计算能力,同时计算多幅投影视图对全息图的作用,即在计算过程中同时将沿着投影方向移位后的一系列角正交投影视图乘以其相应的常数相位因子.其中,每个投影图像的投影角决定了其移位的距离和常数相位因子.将所有并行计算结果累加,可以得到一个包含物体三维信息的二维复矩阵,即菲涅尔全息图.相较于使用计算机中央处理器(central processing unit,CPU)进行计算,本方法显著提升了计算速度,将计算效率提高了30~40倍,为多视角投影全息图的高效生成提供一种可行途径. 展开更多
关键词 信息处理技术 计算全息 全息显示 图形处理单元 角正交投影视图 多视角投影全息
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GPU加速下的三维快速分解后向投影SAS成像算法
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作者 陶鸿博 张东升 黄勇 《系统工程与电子技术》 EI CSCD 北大核心 2024年第10期3247-3256,共10页
后向投影(back projection,BP)算法是一种精确的时域成像算法,但BP算法的计算复杂度高,难以实现实时性成像,特别是在考虑三维成像时,BP算法的计算复杂度会进一步增加。提出一种应用在合成孔径声纳(synthetic aperture sonar,SAS)上的三... 后向投影(back projection,BP)算法是一种精确的时域成像算法,但BP算法的计算复杂度高,难以实现实时性成像,特别是在考虑三维成像时,BP算法的计算复杂度会进一步增加。提出一种应用在合成孔径声纳(synthetic aperture sonar,SAS)上的三维快速分解BP(fast factorized BP,FFBP)成像算法,并利用图形处理器(graphics processing unit,GPU)加速三维FFBP算法。经过对点目标的测试,计算时间从原本的263 s降低到了2.3 s,解决了SAS中的三维成像实时性问题。同时,验证了所提算法在非理想航迹下的成像效果。结果表明,在添加幅度不超过0.1 m(一个波长以内)的正弦扰动时,所提算法对点目标仍有良好的聚焦效果。 展开更多
关键词 快速分解后向投影 并行计算 图形处理器 合成孔径声纳 三维成像
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项目教学法在平面设计教学中的运用措施
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作者 何琦 《湖北开放职业学院学报》 2024年第17期187-188,191,共3页
项目教学法属于一种构建主义教学法,指的是教师在教学时通过设计一个项目,指导学生开展自主研究、合作学习,以加强学生的自主学习能力。高校平面设计教学中引入项目教学法,可以有效提高课堂教学质量,激发学生学习热情。基于此,本文介绍... 项目教学法属于一种构建主义教学法,指的是教师在教学时通过设计一个项目,指导学生开展自主研究、合作学习,以加强学生的自主学习能力。高校平面设计教学中引入项目教学法,可以有效提高课堂教学质量,激发学生学习热情。基于此,本文介绍了项目教学法的含义及其设计原则,同时分析项目教学应用于平面设计教学中的重要性及目前平面设计教学方面存在的问题,并从项目设计、项目实施等方面讨论项目教学法在平面设计中的具体应用方式,以期能为平面设计教学工作提供帮助与参考。 展开更多
关键词 项目教学法 平面设计 教学方法
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陶瓷艺术作品中分形手法的运用 被引量:1
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作者 蔚龙鑫 何芹 《陶瓷》 CAS 2024年第7期114-117,共4页
数千年以来,几何学的研究者一直认为能用几何来揭示自然的奥秘。随着社会的发展,科技与艺术创新日新月异,陶瓷艺术创作与科技创新密不可分。19世纪80年代,分形这一概念一经提出,标志着科学家对于自然科学的研究上升到了更高的高度。笔... 数千年以来,几何学的研究者一直认为能用几何来揭示自然的奥秘。随着社会的发展,科技与艺术创新日新月异,陶瓷艺术创作与科技创新密不可分。19世纪80年代,分形这一概念一经提出,标志着科学家对于自然科学的研究上升到了更高的高度。笔者说明了分形理论发展历程和基本概念,阐述了分形艺术图形的特点如自相似性、和谐性、动态平衡等等并且研究分形生成纹样的基本规律,并且将从陶瓷纹饰与造型2个方面探讨分形艺术在现代陶艺设计中的运用,从而进一步分析陶艺创作的新形式。 展开更多
关键词 陶瓷艺术 分形手法 艺术图形
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项目教学法在平面设计软件课程教学改革与探索——以视觉传达专业方向为例 被引量:1
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作者 陈心怡 《鞋类工艺与设计》 2024年第13期15-17,共3页
项目教学法在平面设计软件类课程教学改革与探索中的应用,以视觉传达专业方向为例。通过引入项目教学法的理念及方法,尝试分析项目教学法在《平面设计软件》课程中的教学创新性和可行性,旨在提高学生的实践能力与创新意识,培养学生综合... 项目教学法在平面设计软件类课程教学改革与探索中的应用,以视觉传达专业方向为例。通过引入项目教学法的理念及方法,尝试分析项目教学法在《平面设计软件》课程中的教学创新性和可行性,旨在提高学生的实践能力与创新意识,培养学生综合素质和团队合作精神。 展开更多
关键词 项目式 平面设计软件课程 教学
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基于粒子群优化BP神经网络的激光扫描投影系统畸变预测方法
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作者 张宏韬 唐芳 +2 位作者 吴坤 朱亦然 侯茂盛 《光子学报》 EI CAS CSCD 北大核心 2024年第6期275-286,共12页
为了精准、高效地预测和校正激光扫描投影系统的畸变误差,研究了基于粒子群优化BP神经网络的畸变预测方法。建立了BP神经网络结构,并融合粒子群优化算法对BP神经网络的权值和阈值进行优化,得出基于粒子群优化BP神经网络的激光扫描投影... 为了精准、高效地预测和校正激光扫描投影系统的畸变误差,研究了基于粒子群优化BP神经网络的畸变预测方法。建立了BP神经网络结构,并融合粒子群优化算法对BP神经网络的权值和阈值进行优化,得出基于粒子群优化BP神经网络的激光扫描投影系统投影畸变预测模型。选取距激光扫描投影仪器两米的待投影面上的理论坐标点及各点相应畸变值Δx作为粒子群优化BP神经网络的训练数据集,将待投影面上实际投影位置坐标代入训练好的粒子群优化BP神经网络进行预测得到预测畸变值输出,并与实际畸变值对比,最后,引入Elman神经网络预测模型的预测结果与所研究预测方法进行对比。结果表明:在±30°的全视场扫描投影范围内粒子群优化BP神经网络预测模型的均方根误差为0.0176 mm,解算时间仅需22.4 s,相较于Elman神经网络效率提升78.33%,预测精度及时间明显优于Elman神经网络,可以有效预测激光扫描投影系统的畸变误差。 展开更多
关键词 激光扫描投影 粒子群优化算法 BP神经网络 误差预测 二维振镜 图形畸变
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生态水利河道规划设计研究
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作者 刘凤喜 《江西建材》 2024年第1期141-143,共3页
文中以某生态水利工程为依托,提出河道规划设计在生态水利工程中的实践;根据传统河道规划设计存在的问题,从平面设计、河道河床设计、断面设计以及生态利用等方面深入分析河道规划设计在生态水利工程中的应用。
关键词 河道规划设计 生态水利工程 平面设计
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工程制图项目式课程改革探索与实践
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作者 周志凌 赖富明 胡砚强 《化工管理》 2024年第25期50-53,共4页
工程制图课程改革在新工科背景下显得尤为关键,其核心在于培养学生的实践与创新能力。当前工程制图教学面临内容同质化、与专业脱节等挑战,导致学生兴趣不浓,教学效果不理想。此次课程改革在化工类工程制图课程中引入了项目教学法,把课... 工程制图课程改革在新工科背景下显得尤为关键,其核心在于培养学生的实践与创新能力。当前工程制图教学面临内容同质化、与专业脱节等挑战,导致学生兴趣不浓,教学效果不理想。此次课程改革在化工类工程制图课程中引入了项目教学法,把课程内容分为四大模块,建立并优化了六大项目群,形成完整项目库。项目库融合了行业前沿、当地特色产业以及思政元素,增强了课程的实用性,有助于学生知识、能力、素质的综合培养。 展开更多
关键词 新工科 工程制图 化工类专业 项目式教学
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