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128 results on '"Shi, Benwei"'

1. On Mergable Coresets for Polytope Distance

Author

Shi, Benwei, Bhaskara, Aditya, Tai, Wai Ming, and Phillips, Jeff M.

Subjects
Computer Science - Computational Geometry, Computer Science - Data Structures and Algorithms, Computer Science - Machine Learning, I.3.5
Abstract

We show that a constant-size constant-error coreset for polytope distance is simple to maintain under merges of coresets. However, increasing the size cannot improve the error bound significantly beyond that constant., Comment: Presented in SoCG'19 Young Researchers Forum (CG:YRF)

Published
2023

3. Pearl River Delta

Author

Xiong, Haixian, Ren, Jie, Liu, Huan, Deng, Junjie, Ye, Leiping, Shi, Benwei, Wu, Jiaxue, Zhang, Weiguo, editor, and Vriend, Huib de, editor

Published
2024
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11. A Deterministic Streaming Sketch for Ridge Regression

Author

Shi, Benwei and Phillips, Jeff M.

Subjects
Computer Science - Machine Learning, Computer Science - Data Structures and Algorithms, Statistics - Machine Learning
Abstract

We provide a deterministic space-efficient algorithm for estimating ridge regression. For $n$ data points with $d$ features and a large enough regularization parameter, we provide a solution within $\varepsilon$ L$_2$ error using only $O(d/\varepsilon)$ space. This is the first $o(d^2)$ space deterministic streaming algorithm with guaranteed solution error and risk bound for this classic problem. The algorithm sketches the covariance matrix by variants of Frequent Directions, which implies it can operate in insertion-only streams and a variety of distributed data settings. In comparisons to randomized sketching algorithms on synthetic and real-world datasets, our algorithm has less empirical error using less space and similar time., Comment: Fix a few typos. To be published in AISTATS 2021

Published
2020

24. Contributors

Author

Chen, Chao, primary, Chen, Hongzhe, additional, Chen, Keliang, additional, Du, Jiabi, additional, He, Zhiguo, additional, Jalón-Rojas, Isabel, additional, Li, Jiasheng, additional, Li, Lu, additional, Li, Li, additional, Liang, Shengkang, additional, Qiao, Lulu, additional, Qiu, Cheng, additional, Shao, Ming, additional, Shi, Benwei, additional, Song, Dehai, additional, Wang, Xiao Hua, additional, Wang, Ya Ping, additional, Wu, Wen, additional, Wu, Hui, additional, Xie, Senyang, additional, Ye, Taoyan, additional, You, Zai-Jin, additional, and Zhu, Jianrong, additional

Published
2019
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33. The Hummocky Patches and Associated Sediment Dynamics Over an Accretional Intertidal Flat

Author

Zhu, Shibing, Chen, Yining, Yan, Weibing, Xing, Fei, Li, Renzhi, Li, Mingliang, Shi, Benwei, and Wang, Ya Ping

Subjects
General Earth and Planetary Sciences
Abstract

Tidal flat system is composed of multiple sub-scale geomorphological units. We found a new mesoscale geomorphological unit on sand-mud mixed intertidal zone along China coast, which was defined as hummocky patches. Hummock patches are most developed in middle tidal flat, with horizontal magnitude of 10–20 m and vertical magnitude of ∼15 cm. Hummocky patches significantly influence local sediment transport, thus affect morphological evolution of tidal flats. In order to understand the formation and development mechanisms of hummocky patches, we collected hydrodynamics, topography, sediment properties, and substrate erosion thresholds data through an in-situ field observation covering a spring-neap tidal cycle over an accretional intertidal flat in Jiangsu, China. We found that sediment characteristics including sorting coefficient (σ: measuring the uniformity of sediment particles) and silt/clay/organic matter/water content are essentially different between hummocky patches and nearby seabed, which leads to spatially varied substrate erosion resistance. The measured erosion thresholds for patches are two times higher comparing to surrounding seabed sediment, which provides foundation for the formation of hummocky patches. Under the impact of periodical tidal currents and waves, surrounding seabed experiences considerably more erosion than patch area, which finally develops to hummocky patches. Therefore, hydrodynamic forces drive the formation and development of patches. The erosion resistance of patches decreases vertically from seabed surface to sublayer, causing initial erosion in the lower sublayer, followed by a mass collapse of the seabed surface layer. Hummocky patches are commonly found in middle tidal zone and their sizes decrease to the shore as tidal currents and waves attenuate with shoreward propagation. Hummocky patches have distinct seasonal variations, which only appear in summer and autumn when wind waves are comparatively lower than winter and spring. We infer the reason is that the strong hydrodynamics caused by winter storms cause larger bottom shear stress than the erosion threshold of hummocky patches, leading to destruction of hummocky patches and a smooth tidal flat surface. This study shed new insight on the knowledge of mesoscale geomorphological units and their formation and development in intertidal flats, which provides crucial information for developing more realistic tidal flat sediment transport and morphological models.

Published
2022

39. Effect of typhoon-induced intertidal-flat erosion on dominant macrobenthic species (Meretrix meretrix)

Author

Sub Inorganic Chemistry and Catalysis, Proceskunde, Section Geography and Education, Coastal dynamics, Fluvial systems and Global change, Shi, Benwei, Yang, Shi Lun, Temmerman, Stijn, Bouma, Tjeerd, Ysebaert, Tom, Wang, Sikai, Zhang, Yingxin, Wu, Jihua, Yang, Haifei, Zhang, Longhui, Zuo, Liqin, Wang, Ya Ping, Sub Inorganic Chemistry and Catalysis, Proceskunde, Section Geography and Education, Coastal dynamics, Fluvial systems and Global change, Shi, Benwei, Yang, Shi Lun, Temmerman, Stijn, Bouma, Tjeerd, Ysebaert, Tom, Wang, Sikai, Zhang, Yingxin, Wu, Jihua, Yang, Haifei, Zhang, Longhui, Zuo, Liqin, and Wang, Ya Ping

Published
2021

40. Role of delta-front erosion in sustaining salt marshes under sea-level rise and fluvial sediment decline

Author

Coastal dynamics, Fluvial systems and Global change, Proceskunde, Energy, Resources & Technological Change, Section Geography and Education, Dynamics of Innovation Systems, Yang, Shi Lun, Luo, Xiangxin, Temmerman, Stijn, Kirwan, Matthew, Bouma, Tjeerd, Xu, Kehui, Zhang, Saisai, Fan, Jiqing, Shi, Benwei, Yang, Haifei, Wang, Ya Ping, Shi, Xuefa, Gao, Shu, Coastal dynamics, Fluvial systems and Global change, Proceskunde, Energy, Resources & Technological Change, Section Geography and Education, Dynamics of Innovation Systems, Yang, Shi Lun, Luo, Xiangxin, Temmerman, Stijn, Kirwan, Matthew, Bouma, Tjeerd, Xu, Kehui, Zhang, Saisai, Fan, Jiqing, Shi, Benwei, Yang, Haifei, Wang, Ya Ping, Shi, Xuefa, and Gao, Shu

Published
2020

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