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799 results on '"Du, Chunlei"'

2. An Efficient Smoothing Proximal Gradient Algorithm for Convex Clustering

Author

Zhou, Xin, Du, Chunlei, and Cai, Xiaodong

Subjects
Computer Science - Machine Learning, Statistics - Methodology, Statistics - Machine Learning
Abstract

Cluster analysis organizes data into sensible groupings and is one of fundamental modes of understanding and learning. The widely used K-means and hierarchical clustering methods can be dramatically suboptimal due to local minima. Recently introduced convex clustering approach formulates clustering as a convex optimization problem and ensures a globally optimal solution. However, the state-of-the-art convex clustering algorithms, based on the alternating direction method of multipliers (ADMM) or the alternating minimization algorithm (AMA), require large computation and memory space, which limits their applications. In this paper, we develop a very efficient smoothing proximal gradient algorithm (Sproga) for convex clustering. Our Sproga is faster than ADMM- or AMA-based convex clustering algorithms by one to two orders of magnitude. The memory space required by Sproga is less than that required by ADMM and AMA by at least one order of magnitude. Computer simulations and real data analysis show that Sproga outperforms several well known clustering algorithms including K-means and hierarchical clustering. The efficiency and superior performance of our algorithm will help convex clustering to find its wide application., Comment: 21 pages, 4 figures

Published
2020

9. How to Plan Urban Parks and the Surrounding Buildings to Maximize the Cooling Effect: A Case Study in Xi'an, China.

Author

Wu, Tianji, Wang, Xuhui, Xuan, Le, Yan, Zhaoyang, Wang, Chao, Du, Chunlei, Su, Yutong, Duan, Jingya, and Yu, Kanhua

Subjects
URBAN heat islands, LAND surface temperature, URBAN parks, THERMAL comfort, URBAN planning, HUMAN comfort
Abstract

Urban areas with parks tend to have the best outdoor thermal comfort in regions with high urban heat island effects during summer. This study analyzed the synergistic cooling effects of 94 urban parks and the adjacent built-up areas in six districts of Xi'an City using four cooling indicators: park cooling intensity (PCI), park cooling area (PCA), park cooling effect (PCE), and park cooling gradient (PCG). The results showed that 84 out of 94 parks exhibited significant cooling effects, with an average PCI of 1.98 °C, PCA of 51.7 ha, PCE of 6.6, and PCG of 8.2 °C/km. Correlation analyses indicated that the intrinsic park attributes, external buffer zone building height, and building density were the main factors affecting the cooling effect. The park landscape configuration, building height, and density significantly influenced the PCI and PCG, while the park shape and size were crucial for the PCA (positive) and PCE (negative). The optimal park areas for improving the thermal environment were identified as 26 ha (cooling area focus, building density <13%) and 15 ha (cooling intensity focus, building height <21 m, density >32%). This study provides theoretical guidance for planning urban parks and the surrounding areas based on cooling effects, offering insights for future climate resilience planning. [ABSTRACT FROM AUTHOR]

Published
2024
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19. New palaeopathology cases of Allosaurus fragilis (Dinosauria: Theropoda).

Author

Xing, Lida, Rothschild, Bruce M., Du, Chunlei, Wang, Donghao, Wen, Kexiang, and Su, Jiayin

Subjects
THORACIC vertebrae, SAURISCHIA, DINOSAURS
Abstract

Here, we describe a pathological sub-adult theropod dinosaur from the Late Jurassic Morrison Formation in Dana Quarry, Wyoming, U.S.A. It exhibits multiple pathologies, involving three dorsal vertebrae, the right scapula and coracoid, and apparent pathology of the left scapula. The fourth dorsal vertebra has four irregularly shaped growths on the vertebral arch. The eighth and ninth vertebrae are fused. The scapulocoracoid joint has an obvious deformity. The distal part of the right scapula is more rounded than normal. The left scapula has a depression on the lateral blade. These pathologies can be identified as follows: the fourth dorsal vertebra is possibly neoplastic or exhibiting compensatory hyperplasia; the eighth and ninth vertebral and the right scapular pathology are consistent with spondyloarthropathy. Diagnoses considered for the left scapula pathology are infections, trauma or unknown. The animal survived the pathologies, which are unlikely the cause of its death. This specimen represents the first known occurrence of spondyloarthropathy in a theropod. [ABSTRACT FROM AUTHOR]

Published
2024
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39. Characterization of tribenuron-methyl-induced male sterility in Brassica juncea L

Author

Guo, Yuan, Gao, Huhu, Ma, Huaiying, Du, Chunlei, Zhang, Dongsuo, Wang, Xiaoyue, and Hu, Shengwu

Subjects
AHAS, Brassica juncea L, cytological observation, food and beverages, tribenuron-methyl, urologic and male genital diseases, male sterility, Research Paper
Abstract

Significant heterosis has been documented in Brassica juncea L. that are grown as agriculturally important oilseeds, vegetables and condiments crops. Male sterility induced by chemical hybridizing agents is an important pollination control system in hybrid crop breeding. Herein, we show that tribenuron-methyl (TBM), a sulfonylurea herbicide, is an effective male gametocide in B. juncea when used at a very low dosage. In the present study, foliar application of various rates of TBM induced a significant increase in pollen sterility in B. juncea (90.57–100%). TBM-treated plants exhibited reductions in size of floral organ and yield components; however, lower dose of TBM (0.075 g a.i. ha–1) did not cause a significant reduction in seed yield per plant. Tapetum cells of TBM-treated plants were hypertrophied and degenerated earlier, and abnormal meiosis was observed at the meiotic stage. A significant decrease of acetohydroxyacid synthase (AHAS) activities was detected in buds of plants treated with 0.10 g a.i. ha–1 TBM, and RT-qPCR analysis showed that TBM exposure perturbed AHAS expression in small buds, which support that TBM induces male sterility in B. juncea by targeting AHAS expression. Our results suggest that TBM could be used as an efficient chemical hybridization agent in B. juncea, which has practical implications for the application of hybrid breeding in B. juncea.

Published
2021

41. Application of improved CART algorithm in prediction of water inrush from coal seam floor

Author

DU Chunlei, ZHANG Xueying, and LI Fenglia

Subjects
coal seam floor, water inrush prediction, cart algorithm, decision tree model, optimal threshold, Mining engineering. Metallurgy, TN1-997
Abstract

In view of disadvantages of long time-consuming and low prediction accuracy existed in prediction model of water inrush from coal seam floor based on traditional CART algorithm, a decision tree model based on improved CART algorithm was introduced, and the decision tree model was used to establish prediction model of water inrush from coal seam floor. The experiment results show that running time of the prediction model of water inrush from coal seam floor based on improved CART algorithm is reduced from 1.0411 s to 0.6125 s, and prediction accuracy rate is improved from 88.78% to 95.54%.

Published
2014
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