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Survey on computational 3D visual optical art design
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作者 Kang Wu Xiao‑Ming Fu +1 位作者 Renjie Chen ligang liu 《Visual Computing for Industry,Biomedicine,and Art》 EI 2022年第1期378-408,共31页
Visual arts refer to art experienced primarily through vision.3D visual optical art is one of them.Artists use their rich imagination and experience to combine light and objects to give viewers an unforgettable visual... Visual arts refer to art experienced primarily through vision.3D visual optical art is one of them.Artists use their rich imagination and experience to combine light and objects to give viewers an unforgettable visual experience.How-ever,the design process involves much trial and error;therefore,it is often very time-consuming.This has prompted many researchers to focus on proposing various algorithms to simplify the complicated design processes and help artists quickly realize the arts in their minds.To help computer graphics researchers interested in creating 3D visual optical art,we first classify and review relevant studies,then extract a general framework for solving 3D visual optical art design problems,and finally propose possible directions for future research. 展开更多
关键词 Computational art 3D visual art Automatic art design Optical art
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Practical construction of globally injective parameterizations with positional constraints
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作者 Qi Wang Wen-Xiang Zhang +2 位作者 Yuan-Yuan Cheng ligang liu Xiao-Ming Fu 《Computational Visual Media》 SCIE EI CSCD 2023年第2期265-277,共13页
We propose a novel method to compute globally injective parameterizations with arbitrary positional constraints on disk topology meshes.Central to this method is the use of a scaffold mesh that reduces the globally in... We propose a novel method to compute globally injective parameterizations with arbitrary positional constraints on disk topology meshes.Central to this method is the use of a scaffold mesh that reduces the globally injective constraint to a locally flipfree condition.Hence,given an initial parameterized mesh containing flipped triangles and satisfying the positional constraints,we only need to remove the flips of a overall mesh consisting of the parameterized mesh and the scaffold mesh while always meeting positional constraints.To successfully apply this idea,we develop two key techniques.Firstly,an initialization method is used to generate a valid scaffold mesh and mitigate difficulties in eliminating flips.Secondly,edgebased remeshing is used to optimize the regularity of the scaffold mesh containing flips,thereby improving practical robustness.Compared to state-of-the-art methods,our method is much more robust.We demonstrate the capability and feasibility of our method on a large number of complex meshes. 展开更多
关键词 globally injective parameterization constrained parameterization BIJECTION flip-free scaffold mesh
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Pass-through Effects of Global Commodity Prices on China's Inflation:An Empirical Investigation 被引量:8
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作者 ligang liu Andrew Tsang 《China & World Economy》 SCIE 2008年第6期22-34,共13页
The present paper uses a two-step approach to estimate the pass-through effects of changes in international commodity prices and the RMB exchange rate on domestic consumer price inflation in China. We first estimate t... The present paper uses a two-step approach to estimate the pass-through effects of changes in international commodity prices and the RMB exchange rate on domestic consumer price inflation in China. We first estimate the pass-through effects of international commodity prices on producer prices and then estimate the pass-through effects of producer price inflation on consumer price inflation. We find that a l O-percent increase in international commodity prices would lead to China' s producer prices increasing by 1.2 percent 3 months later, which in turn would increase China' s domestic inflation by 0.24 percent over the same period. However, a 10-percent appreciation of the RMB exchange rate against the US dollar would help to reduce increases in producer prices by 4.4 percent over the following 3 months, which in turn would lead to a 0. 89-percent decline in consumer price inflation over the same period. Our findings suggest that appreciation of the RMB in an environment of rising global commodity prices and a weak US dollar could be an effective instrument to help contain inflation in China. 展开更多
关键词 China commodity price exchange rate PASS-THROUGH
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Impact of the Global Financial Crisis on China: Empirical Evidence and Policy Implications 被引量:6
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作者 ligang liu 《China & World Economy》 SCIE 2009年第6期1-23,共23页
This paper applies a structural vector autoregression analysis to quantify the impact of the global financial crisis on China. It is found that the impact is indeed sizeable: a 1-percent decline in economic growth in... This paper applies a structural vector autoregression analysis to quantify the impact of the global financial crisis on China. It is found that the impact is indeed sizeable: a 1-percent decline in economic growth in the USA, the EU and Japan is likely to lead to a0. 73-percent decline in growth in China. The article discusses whether the current measures of fiscal stimulus are adequate to offset the sharp decline in external demand Although there is little doubt that the massive fiscal stimulus will largely offset the significant shortfalls in external demand, the current growth pattern in China will be increasingly unsustainable in the long term. China "s reform cycles suggest that external shocks are often opportunities for structural reforms. Therefore, the crisis could also be a catulyst for rebalancing China 's economic structure so as to return the economy to a sustainable path. 展开更多
关键词 China global financial crisis structural vector autoregression analysis
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A survey of sketch based modeling systems 被引量:5
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作者 Chao DING ligang liu 《Frontiers of Computer Science》 SCIE EI CSCD 2016年第6期985-999,共15页
As 3D technology, including computer graphics, virtual reality and 3D printing, has been rapidly developed in the past years, 3D models are gaining an increasingly huge demand. Traditional 3D modeling platforms such a... As 3D technology, including computer graphics, virtual reality and 3D printing, has been rapidly developed in the past years, 3D models are gaining an increasingly huge demand. Traditional 3D modeling platforms such as Maya and ZBrush, utilize "windows, icons, menus, pointers" (WlMP) interface paradigms for fine-grained control to construct detailed models. However, the modeling progress can be tedious and frustrating and thus too hard for a novice user or even a well trained artist. Therefore, a more intuitive interface is needed. Sketch, an intuitive communication and modeling tool for human beings, becomes the first choice of modeling community. So far, various sketch-based modeling systems have been created and studied. In this paper, we at- tempt to show how these systems work and give a comprehensive survey. We review and categorize the systems in four aspects: the input, the knowledge they use, the modeling approach and the output. We also discuss about inherent challenges and open problems for researchers in the future. 展开更多
关键词 sketch-based modeling interactive design sketch comprehension
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Inversion-free geometric mapping construction: A survey 被引量:1
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作者 Xiao-Ming Fu Jian-Ping Su +3 位作者 Zheng-Yu Zhao Qing Fang Chunyang Ye ligang liu 《Computational Visual Media》 EI CSCD 2021年第3期289-318,共30页
A geometric mapping establishes a correspondence between two domains.Since no real object has zero or negative volume,such a mapping is required to be inversion-free.Computing inversion-free mappings is a fundamental ... A geometric mapping establishes a correspondence between two domains.Since no real object has zero or negative volume,such a mapping is required to be inversion-free.Computing inversion-free mappings is a fundamental task in numerous computer graphics and geometric processing applications,such as deformation,texture mapping,mesh generation,and others.This task is usually formulated as a non-convex,nonlinear,constrained optimization problem.Various methods have been developed to solve this optimization problem.As well as being inversion-free,different applications have various further requirements.We expand the discussion in two directions to(i)problems imposing specific constraints and(ii)combinatorial problems.This report provides a systematic overview of inversion-free mapping construction,a detailed discussion of the construction methods,including their strengths and weaknesses,and a description of open problems in this research field. 展开更多
关键词 inversion-free mapping Jacobian matrix DISTORTION first-order methods second-order methods
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Manifold Construction Over Polyhedral Mesh 被引量:1
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作者 Chun Zhang ligang liu 《Communications in Mathematics and Statistics》 SCIE 2017年第3期317-333,共17页
We present a smooth parametric surface construction method over polyhe-dral mesh with arbitrary topology based on manifold construction theory.The surface is automatically generated with any required smoothness,and it... We present a smooth parametric surface construction method over polyhe-dral mesh with arbitrary topology based on manifold construction theory.The surface is automatically generated with any required smoothness,and it has an explicit form.As prior methods that build manifolds from meshes need some preprocess to get poly-hedral meshes with specialtypes of connectivity,such as quad mesh and triangle mesh,the preprocess will result in more charts.By a skillful use of a kind of bivariate spline function which defines on arbitrary shape of 2D polygon,we introduce an approach that directly works on the input mesh without such preprocess.Fornon-closedpolyhe-dral mesh,we apply a global parameterization and directly divide it into several charts.As for closed polyhedral mesh,we propose to segment the mesh into a sequence of quadrilateral patches without any overlaps.As each patch is an non-closed polyhedral mesh,the non-closed surface construction method can be applied.And all the patches are smoothly stitched with a special process on the boundary charts which define on the boundary vertex of each patch.Thus,the final constructed surface can also achieve any required smoothness. 展开更多
关键词 Manifold construction SMOOTHNESS Polyhedral mesh Arbitrary connectivity
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Discretizing Laplace–Beltrami Operator from Differential Quantities 被引量:1
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作者 Ruimin Wang Zhouwang Yang +1 位作者 ligang liu Qing Chen 《Communications in Mathematics and Statistics》 SCIE 2013年第3期331-350,共20页
The Laplace–Beltrami operator(LBO)is the fundamental geometric object associated with manifold surfaces and has been widely used in various tasks in geometric processing.By understanding that the LBO can be computed ... The Laplace–Beltrami operator(LBO)is the fundamental geometric object associated with manifold surfaces and has been widely used in various tasks in geometric processing.By understanding that the LBO can be computed by differential quantities,we propose an approach for discretizing the LBO on manifolds by estimating differential quantities.For a point on the manifold,we first fit a quadratic surface to this point and its neighborhood by minimizing the least-square energy function.Then we compute the first-and second-order differential quantities by the approximated quadratic surface.Finally the discrete LBO at this point is computed from the estimated differential quantities and thus the Laplacian matrix over the discrete manifold is constructed.Our approach has several advantages:it is simple and efficient and insensitive to noise and boundaries.Experimental results have shown that our approach performs better than most of the current approaches.We also propose a feature-aware scheme for modifying the Laplacian matrix.The modified Laplacian matrix can be used in other feature preserving geometric processing applications. 展开更多
关键词 Laplace-Beltrami operator DISCRETIZATION Differential quantities
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A Revisit of Shape Editing Techniques:From the Geometric to the Neural Viewpoint
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作者 Yu-Jie Yuan Yu-Kun Lai +2 位作者 Tong Wu Lin Gao ligang liu 《Journal of Computer Science & Technology》 SCIE EI CSCD 2021年第3期520-554,共35页
3D shape editing is widely used in a range of applications such as movie production,computer games and computer aided design.It is also a popular research topic in computer graphics and computer vision.In past decades... 3D shape editing is widely used in a range of applications such as movie production,computer games and computer aided design.It is also a popular research topic in computer graphics and computer vision.In past decades,researchers have developed a series of editing methods to make the editing process faster,more robust,and more reliable.Traditionally,the deformed shape is determined by the optimal transformation and weights for an energy formulation.With increasing availability of 3D shapes on the Internet,data-driven methods were proposed to improve the editing results.More recently as the deep neural networks became popular,many deep learning based editing methods have been developed in this field,which are naturally data-driven.We mainly survey recent research studies from the geometric viewpoint to those emerging neural deformation techniques and categorize them into organic shape editing methods and man-made model editing methods.Both traditional methods and recent neural network based methods are reviewed. 展开更多
关键词 mesh deformation man-made model editing deformation representation optimization deep learning
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Has China Crowded out Foreign Direct Investment from Its Developing East Asian Neighbors?
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作者 ligang liu Kevin Chow Unias Li 《China & World Economy》 SCIE 2007年第3期70-88,共19页
This paper applies a gravity model to investigate the determinants of foreign direct investment (FDI) in East Asia. Economic fundamentals, such as market size, per capita income and country risk indicators, economic... This paper applies a gravity model to investigate the determinants of foreign direct investment (FDI) in East Asia. Economic fundamentals, such as market size, per capita income and country risk indicators, economic and cultural ties, exchange rate volatilities and information asymmetry are found to be important determinants for FDL Globally, the inward FDI among high-income OECD economies declined significantly on average over the period of 1990-2003, whereas the inward FDI of the high-income OECD economies in emerging market economies gained substantially. In the East Asian region, the ASEAN-4 (Indonesia, Malaysia, the Philippines and Thailand) received above-average inward FDI from the high-income OECD economies after controlling for their economic fundamentals. By contrast, China's FDl from the high-income OECD economies is below average relative to its economic fundamentals. Therefore, it is difficult to establish that China has crowded out FDI from its developing ASEAN neighbors. 展开更多
关键词 ASEAN China crowding out foreign direct investment
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