100 research outputs found
Contribution of factor structure change to China’s economic growth: evidence from the time-varying elastic production function model
The time-varying factor share runs through the entire process of
the Chinese economic miracle, unlike the ‘Kaldor Facts’ in developed
countries. Following the new structural economics theory,
we construct a time-varying elastic production function model
that characterises the structural changes of China’s economic
element, and decompose the driving force of economic growth
to measure the contribution of factor structure. We found that,
from 1978–2017, the average contribution of capital, labour,
technological progress, and factor structure change to the GDP
was 67.01%, 10.38%, 23.08%, and 0.47%, respectively. The measurement
results can aptly portray the impact of policy changes in
China’s unique gradual reform process, such as the economic
market reforms in 1992, the global financial crisis in 2008, and the
policy changes of the new economic normal in 2014. Meanwhile,
the results reveal that improving factor allocation can accelerate
the total factor productivity and promote high-quality development
of China’s economy
Numerical Modeling of Bank Erosion Processes and Its Field Application
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Erosion Control Plans for JiJi Weir Downstream Channel
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Modeling River Morphodynamic Process Using a Depth-Averaged Computational Model and an Application to a Mountain River
Bank erosion is a dominant river morphodynamic process resulting in encroaching valuable farming land and channel migration. Prediction of bank erosion and channel migration requires understanding of the morphodynamics of the entire river system. Numerical modeling is an ideal method for this task. However, models with full capabilities and applications on complex real-world problems are rare. In this study the finite element-based computational model, CCHE2D, and its flow, sediment transport, and bank erosion modules are introduced. The model is capable of simulating unsteady flows with nonuniform sediment transport and cohesive/non-cohesive material bank erosion. The effects of helical secondary current on sediment transport induced by flow curvatures are reflected in both bed load and suspended sediment formulations. This model is validated using multiple sets of experimental data and applied to bank erosion problems of the Chuoshui River, a real-world mountain river in Taiwan. Characterized by typhoon floods, steep channel slopes, and high sediment load and mobility, this river often exhibits a braided pattern consisting of multiple curved channels. Channel bed change and bank erosion caused by 10 years of typhoon floods in a selected reach have been simulated, and the computed bank erosion results agreed with the field observation
Towards Omni-generalizable Neural Methods for Vehicle Routing Problems
Learning heuristics for vehicle routing problems (VRPs) has gained much
attention due to the less reliance on hand-crafted rules. However, existing
methods are typically trained and tested on the same task with a fixed size and
distribution (of nodes), and hence suffer from limited generalization
performance. This paper studies a challenging yet realistic setting, which
considers generalization across both size and distribution in VRPs. We propose
a generic meta-learning framework, which enables effective training of an
initialized model with the capability of fast adaptation to new tasks during
inference. We further develop a simple yet efficient approximation method to
reduce the training overhead. Extensive experiments on both synthetic and
benchmark instances of the traveling salesman problem (TSP) and capacitated
vehicle routing problem (CVRP) demonstrate the effectiveness of our method. The
code is available at: https://github.com/RoyalSkye/Omni-VRP.Comment: Accepted at ICML 202
Techniques for mesh density control
Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732Mesh generation is crucial in computational fluids dynamic (CFD) analysis, which solves a set of partial differential equations (PDE) based on a computational mesh. To a large extent, the success of solving these equations depends on the mesh quality. In addition to the orthogonality and the smoothness, the mesh density distribution is the key to a desirable mesh. The objective of the current research is to develop methods which make the control of mesh density simple and effective. The resulting mesh is near-orthogonal but more desirable for the numerical simulation.
In this study, two new techniques for mesh density control are proposed. The first one is a three-parameter stretching function which stretches the nodes along a line in two directions and control their location of the distribution. The second method is a modified RL system (Ryskin and Leal, 1983) in which the distortion function is evaluated by the averaged scale factors and the scale factors which are formulated by weighting functions of desired mesh density distribution
Structured Mesh Generation along Louisiana-Mississippi Coastline for Simulation of Coastal Processes
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
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