7 results on '"Wang, Degen"'
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2. A Clutter Suppression Algorithm via Enhanced Sparse Bayesian Learning for Airborne Radar
- Author
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Wang, Degen, Wang, Tong, Cui, Weichen, and Zhang, Xinying
- Abstract
The traditional space–time adaptive processing (STAP) method based on sparse Bayesian learning (SBL) has the problems of low computational efficiency and slow convergence speed. In this article, a novel SBL approach based on a statistical threshold is proposed to address these issues. To discriminate between the active and inactive atoms of the dictionary, we first develop an adaptive decision test. Next, the adaptive decision test is integrated into the SBL method, which increases its accuracy and convergence rate. In addition, the detection threshold has an important property that is independent of signal and noise power. Therefore, the adaptive decision test is robust to external changes. Numerous simulations demonstrate that the proposed algorithm has excellent clutter suppression performance and fast convergence rate.
- Published
- 2023
- Full Text
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3. Spatial differentiation and influence mechanism of the connection-distribution performance of urban high-speed railway hub in the Yangtze River Economic Belt
- Author
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Wang, Degen, Xu, Yinfeng, and Zhao, Meifeng
- Abstract
A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt, and is the basic factor responsible for the promotion of this belt. A high-speed railway hub has the “last kilometer of time-space compression” effect and is the key to building an efficient, convenient, modern, and comprehensive transportation system. This study constructed a model for measuring the connection-distribution performance of the high-speed railway hub, determined the connection-distribution performance of the urban high-speed railway hub in the Yangtze River Economic Belt, and analyzed its spatial differentiation characteristics, further revealed the influencing mechanism of the connection-distribution performance of the high-speed railway hub. The main results are as follows: (1) The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt presented an “olive-shaped pattern” grade structure with two small ends and a large middle section, that is, the number of high-speed railway stations with high performance and average performance was small, and the number of high-speed railway stations with good performance and medium performance was large. (2) The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt showed a regional differentiation pattern of “high in the east and low in the west” and “high in the north and low in the south”, and showed an urban agglomeration differentiation pattern of “high in the core areas but low in the marginal areas”; moreover, spatial differences were prominent in the distribution of nine evaluation indexes of the connection-distribution performance of the high-speed railway hub. (3) GDP, urbanization rate, city level, station passenger flow and frequency of shuttle bus were key driving factors affecting the connection-distribution performance of the high-speed railway hub. At the same time, there were significant differences in the key driving factors for the connection-distribution performance grades of high-quality, good, medium and average.
- Published
- 2022
- Full Text
- View/download PDF
4. A novel gridless space-time adaptive processing method based cyclic minimization.
- Author
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Wang, Degen, Wang, Tong, Cui, Weichen, and Zhang, Xinying
- Subjects
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SPACETIME - Abstract
Space-time adaptive processing (STAP) algorithm based on sparse recovery (SR) can effectively suppress clutter in limited sample scenarios. However, the clutter suppression performance will be reduced because of grid mismatch (off-grid), which happens when the clutter ridge fails to match the dictionary. To address this issue, a novel gridless STAP algorithm based on cyclic minimization is proposed in this paper. Compared with the STAP algorithm based on atomic norm minimization (ANM), the proposed algorithm avoids the approximate loss caused by relaxing the rank norm to the nuclear norm. In addition, in order to improve the computational efficiency, we derive a fast iterative structure based on the alternating direction method of multipliers (ADMM) framework. The proposed algorithm offers better clutter suppression performance and excellent computational efficiency, according to a vast collection of experiments based on simulation data and measured data. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Evolution and spatial characteristics of tourism field strength of cities linked by high-speed rail (HSR) network in China
- Author
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Wang, Degen, Niu, Yu, Sun, Feng, Wang, Kaiyong, Qian, Jia, and Li, Feng
- Abstract
Traffic is an indispensable prerequisite for a tourism system. The “four vertical and four horizontal” HSR network represents an important milestone of the “traffic revolution” in China. It will affect the spatial pattern of tourism accessibility in Chinese cities, thus substantially increasing their power to attract tourists and their radiation force. This paper examines the evolution and spatial characteristics of the power to attract tourism of cities linked by China’s HSR network by measuring the influence of accessibility of 338 HSR-linked cities using GIS analysis. The results show the following. (1) The accessibility of Chinese cities is optimized by the HSR network, whose spatial pattern of accessibility exhibits an obvious traffic direction and causes a high-speed rail-corridor effect. (2) The spatial pattern of tourism field strength in Chinese cities exhibits the dual characteristics of multi-center annular divergence and dendritic diffusion. Dendritic diffusion is particularly more obvious along the HSR line. The change rate of urban tourism field strength forms a high-value corridor along the HSR line and exhibits a spatial pattern of decreasing area from the center to the outer limit along the HSR line. (3) The influence of the higher and highest tourism field strength areas along the HSR line is most significant, and the number of cities that distribute into these two types of tourism field strengths significantly increases: their area expands by more than 100%. HSR enhances the tourism field strength value of regional central cities, and the radiation range of tourism attraction extends along the HSR line.
- Published
- 2017
- Full Text
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6. HSR mechanisms and effects on the spatial structure of regional tourism in China
- Author
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Wang, Degen, Wang, Li, Chen, Tian, Lu, Lin, Niu, Yu, and Alan, August
- Abstract
Chinese railway has entered the “HSR era”, while the structure of “four vertical and four horizontal” railways for transit passengers is almost completed. Taking the Beijing- Shanghai High-Speed Rail (hereinafter referred to as HSR) as an example, this paper first explores HSR’s effects on the spatial structure of regional tourist flows using the social network analysis. Next, it notes changes in the accessibility of regional transportation. After analyzing the factors including initial endowment of regional tourism resources, hospitality facilities, the density of the regional tourism transportation network, and locations, the paper discusses the mechanisms through which HSR affects regional tourist flows. The study shows the following: (1) HSR’s effects on the spatial structure of regional tourist flows are manifested through the Matthew effect, the filtering effect, the diffusion effect and the overlying effect, and (2) the Matthew effect of HSR is manifested under an obvious interaction of the location, the initial endowment of tourism resources, hospitality capacity, tourist transportation network density and “time-space compression”. The filtering effect of HSR is manifested for those tourism nodes without favorable location conditions, endowment of tourism resources, hospitality capacity, or tourist transportation network density and without obvious benefits from “time-space compression”. Those tourism nodes that boast advantages in terms of location condition, endowment of tourism resources, hospitality capacity, tourist transportation network density and obvious “time-space compression” will become sources for the diffusion effect. HSR will strengthen the aggregation effects of tourist flow in these diffusion sources, which will thereafter diffuse to peripheral tourist areas, manifesting “aggregation-diffusion”. HSR has overlapped tourists’ spatial traveling range over large-scale spaces. However, the overlying effect is only generated in those tourism nodes with a favorable location condition, an endowment of tourism resources, hospitality capacity, tourist transportation network density, and obvious “time-space compression”.
- Published
- 2016
- Full Text
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7. Temporal-spatial change and driving mechanism for regional difference of domestic tourism in China
- Author
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Wang, Degen and Chen, Tian
- Abstract
By using the variation coefficient, Gini coefficient and Theil coefficient, this paper makes preliminary exploration of temporal-spatial change features and driving mechanism for regional differences of domestic tourism in China from 1995 to 2009. According to the results, we drew the following conclusions: (1) The regional difference of domestic tourism in China tends to be narrowing generally, and is less than that of inbound tourism, playing an important role in narrowing the overall gap of regional tourism in China. (2) The regional internal difference features: inter-provincial difference in the eastern region and difference among the eastern, central and western regions are comparatively obvious and demonstrate a significantly shrinking tendency, the change tendency is consistent with the change tendency of overall difference and exercises a decisive role in overall difference, whereas the inter-provincial difference in the central and western regions is small and relatively stable, having less influence on the overall difference. (3) The temporal-spatial change in regional difference is featured by: low-level provinces occupy a majority and are concentrated in the central and western regions, showing a tendency of narrowing difference; high-level provinces are concentrated in the eastern region, showing a tendency of spreading to the central and western regions; spatial pattern of regional difference demonstrates 4 types, i.e. “proliferation type”, “polarization type”, “quiescence type” and “collapse type.” (4) The driving force for regional difference of domestic tourism in China comes down to 3 aspects: regional socio-economic attribute, regional transport accessibility level and regional development policy.
- Published
- 2013
- Full Text
- View/download PDF
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