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Model Selection for Support Vector Machines Based on kernel density Estimation

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Model Selection for Support Vector Machines Based on Kernel ...

Mapping the spatial and temporal patterns of fallow land in mountainous regions of China

2010 Chinese Control and Decision Conference

作者： Zhu Jin,Xiaoping Ma The School of Information and Electrical Engineering,China University of Mining & Technology,Xuzhou,Jiangsu 221116,China

＜正＞This paper,aiming at overcoming the obstacles in selection of optimal kernel and its parameters,proposes a model selection approach of kernel parameters for Support Vector Machine based on kernel density estimation.By investigating kernel density estimation theory,the kernel density function based on inner product relationship of data distribution in high dimensional feature space is constructed,at the same time an evaluation function on performance of kernel mapping is established.Experimental results on both synthetic dataset and practical dataset show that proposed method is able to effectively avoid such limitations as high computational cost and process complexity in traditional model selection,and capable of optimizing kernel parameters as well as keeping better classification accuracy.So,our approach is feasible and effective.

关键词： Support Vector Machine kernel density Model Selection

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International Journal of Digital Earth 2022年第1期15卷 2148-2167页

作者： Wen Song Alexander V.Prishchepov Wei Song Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China School of Geomatics and Urban Spatial Informatics Beijing University of Civil Engineering and ArchitectureBeijingPeople’s Republic of China Department of Geosciences and Natural Resource Management (IGN) University of CopenhagenKøbenhavn KDenmark Department of Theoretical Cybernetics and Applied Mathematics Altai State UniversityBarnaulRussia

The rapid growth of the global population has resulted in a continuous increase in cropland intensity and a shortening of the fallow period as part of the cropland rotation cycle.Yet,there is a lack of systematic knowledge on the extent of fallow lands,particularly in complex landscapes,such as the mountainous regions of China.To fill this knowledge gap,taking Yuanyang County(YYC),Yunnan Province,China,as a case study,we tested a method to identify the spatial-temporal distribution of fallow land by mapping cropland with Landsat data.The overall accuracy of land cover classification,including cropland,ranged between 90.1%and 95.8%from 1998 to 2019.The average accuracy of fallow plots was 75.7%from 2001 to 2019.The annual fallow rate varied between 8.3%and 54.3%,with an average of 20.7%.kernel density estimated with the probability density function showed that fallow varied between 5 and 13 blocks per km2,gradually decreasing from the central area to the periphery.Increasing elevation,the low value of regional domestic products,and the increased distance to rural settlements were closely related to the higher proportions of fallow land.The approach presented here can be applied to map fallow land in other regions.

关键词： Remote sensing fallow land kernel density time series China

Regional difference and dynamic evolution of development quality of power industry in China

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Chinese Journal of Population,Resources and Environment 2023年第1期21卷 1-12页

作者： Sha Yu Yongjian Pu Lefeng Shi Hao Yu Yixiang Huang School of Economics and Business Administration Chongqing UniversityChongqing 400044China National Center for Applied Mathematics in Chongqing Chongqing Normal UniversityChongqing 401331China College of Economics and Management Northwest A&F UniversityYangling 712100China

To achieve the goals of carbon peaking and carbon neutrality and maintain high-quality economic growth,China is currently striving to improve the quality of development of its power sector.In this regard,revealing the regional differences and evolutionary trends in the development quality of China’power sector has a high value to inspire the next improvement direction toward how to integrate regional power recourses to an overall optimization level.Motived by this purpose,this paper uses the entropy method to evaluate the com‐prehensive and subsystem indices of the development quality of the power industry,and reveals their re‐gional differences and evolutionary trends with the help of the Dagum Gini coefficient and kernel density es‐timation methods.The findings show that:There are obvious regional differences in the development quality of China’s power industry,and the differences are steadily declining in all regions except the West.Regional differences are mainly derived from inter-regional differences,with the largest inter-regional differences in the East-Northeast region.Intra-regional differences show a distribution pattern of East>West>North‐east>Center.

关键词： Development quality of power industry Regional difference The Dagum Gini Dynamic evolution kernel density

Spatial location differentiation and development decision optimization of characteristic villages and towns in China

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Geography and Sustainability 2022年第1期3卷 21-31页

作者： Jintao Li Yuling Gong Institute of Governance Shandong UniversityQingdao 266200China School of Politics and Public Administration Shandong UniversityQingdao 266200China Centre for Quality of Life and Public Policy Research Shandong UniversityQingdao 266237China School of Environmental Science and Engineering Shandong UniversityQingdao 266200China Institute of Eco-Environmental Forensics Shandong UniversityQingdao 266200China

Due to rapid urbanization and industrialization,the gap between urban and rural development has gradually increased.Rural development problems have been a significant topic of discussion,and are related to people’s livelihoods.This article built a point-axis-region location driving system to analyze the spatial location differentiation of characteristic villages and towns(CVTS)using the kernel density model,and explored the mechanism of location driving factors with a geographical detector model.The results show that vegetables and fruits are the main types of products in CVTS.They account for 27.60%and 34.68%of all types of products,and occur mainly in the east and central regions of China.Moreover,all point-axis-region driving factors have a significant influence on grain crops.The mean values of driving forces of vegetables and fruits are larger than other types of CVTS,and their values are 0.12 and 0.11.The average driving forces on all CVTS in the northeast are higher than those in other regions,especially the driving forces of vegetables and medicinal crops(0.24 and 0.18,respectively).Finally,we proposed that the Chinese government should employ engineering technology,invest on road networks,e-commerce and blockchain technology to optimize the point-axis-region location advantages,to promote the sustainable development of CVTS.The detection of driving mechanisms on spatial location differentiation of CVTS has important research value for location theory and rural region systems research.

关键词： Characteristic villages and towns Point-axis-region driving system Spatial driving factors Decision optimization kernel density

GPS tracking of non-breeding ravens reveals the importance of anthropogenic food sources during their dispersal in the Eastern Alps

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Current Zoology 2016年第4期62卷 337-344页

作者： Matthias-Claudio LORETTO Richard SCHUSTER Thomas BUGNYAR Department of Cognitive Biology University of Vienna Althanstrasse 14 A-1090 vienna Konrad Lorenz Forschungsstelle Core Facility for Behaviour and Cognition University of Vienna Fischerau 11 A-4645 GrLinau im Almtal Austria CDepartment of Forest and Conservation Sciences University of British Columbia Vancouver B.C. Canada V6T1Z4

In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens' behavior during dispersal in the Eastern Alps. We deployed Global Positioning System (GPS) loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify: 1) the dimension of the birds' space use (home range size with seasonal effects and daily/long-term travel distances), 2) how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3) their destination of movements. We recorded movements of up to 40 km per hour, more than 160 km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and combines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these "feeding hot spots" and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.

关键词： Corvus corax common raven dispersal kernel density non-breeder space use

Identifying the Geography and Determinants of O2O Online Retailers in Megacity in Central China:A Case Study of Zhengzhou City

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Chinese Geographical Science 2021年第5期31卷 931-950页

作者： QI Jinghui NIU Shuwen YE Chenxi WANG Luojia WEl Yongna WEN Yuzhao ZHAO Shuling College of Civil Engineering and ArchitecturelCollaborative Imnovation Center for Aviation Economy Development Zhengzhou University of AeronauticsZhengzhou 450046China College of Earth and Environmental Sciences Lanzhou UniversityLanzhou 730000China School of Business Zhengzhou University of AeronauticsZhengzhou 450046China School of Economics Lanzhou University of Finance and EconomicsLanzhou 730101China College of Environment and Planning Henan UniversityKaifeng 475004China College of Resource and Environment Henan University of Economics and LawZhengzhou 450046China

In recent years,O2O e-commerce,represented by online group-buying,has developed vigorously,which had significant impacts on urban commercial space.Zhengzhou City is a rising national central city in China,and its e-commerce development level is ahead,but relevant researches are rare.Therefore,the data of online retailers of *** was collected and combined with Baidu map and Baidu heat map data.Then,we adopted the methods such as spatial statistics and geodetector to explore the geography and determinants of O2O online retailers in Zhengzhou urban area.The main conclusions are 1)The spatial development of O2O online retailers is characterized by significant global high-value agglomeration.2)The agglomeration areas of different types of O2O online retailers are different.Most of them are concentrated in the old urban area within the Third Ring Road of Zhengzhou City,forming five comprehensive agglomeration areas.3)The areas with the high e-commerce development level are mainly concentrated in the northeast and southwest of the x-shaped region formed by the intersection of Lianyungang-Lanzhou and Beijing-Guangzhou railways.Erqi Square and Guomao 360 Plaza are at the highest development level,followed by Zhongyuan Wanda Plaza and Daxue Middle Road.The development level at other areas is relatively low.4)Zhengzhou’s O2O commercial pattern is highly dependent on physical business.The population distribution,especially the population distribution during the nightlife period,plays a vital role in its spatial development,followed by accessibility.The influences of physical distance are slightly larger than that of time cost,but the difference between them is little.In addition,travelling costs have the least impact.This paper could provide certain references for urban commercial planning.

关键词： O2O online retailers geodetector kernel density spatial development Zhengzhou City China

Risk Prevention and Control for Agricultural Non-Point Source Pollution Based on the Process of Pressure-Transformation-Absorption in Chongqing, China

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Chinese Geographical Science 2021年第4期31卷 735-750页

作者： ZHU Kangwen CHEN Yucheng ZHANG Sheng YANG Zhimin HUANG Lei LEI Bo XIONG Hailing WU Sheng LI Xixi College of Resources and Environment Southwest UniversityChongqing 400716China Chongqing Engineering Research Center of Rural Cleaning Chongqing 400716China Chongqing Academy of Ecology and Environmental Sciences Chongqing 401147China College of Computer&Information Science Southwest UniversityChongqing 400716China Chongqing Chemical Industry Vocational College^Chongqing 401220 China

According to China’s second national survey of pollution sources, the contribution of agricultural non-point sources(ANS) to water pollution is still high. Risk prevention and control are the main means to control costs and improve the efficiency of ANS, but most studies directly take pollution load as the risk standard, leading to a considerable misjudgment of the actual pollution risk. To objectively reflect the risk of agricultural non-point source pollution(ANSP) in Chongqing, China, we investigated the influences of initial source input, intermediate transformation, and terminal absorption of pollutants via literature research and the Delphi method and built a PTA(pressure kinetic energy, transformation kinetic energy, and absorption kinetic energy) model that covers 12 factors, with the support of geographical information system(GIS) technology. The terrain factor calculation results and the calculation results of other factors were optimized by Python tools to reduce human error and workload. Via centroid migration analysis and kernel density analysis, the risk level, spatial aggregation degree, and key prevention and control regions could be accurately determined. There was a positive correlation between the water quality of the rivers in Chongqing and the risk assessment results of different periods, indirectly reflecting the reliability of the assessment results by the proposed model. There was an obvious tendency for the low-risk regions transforming into high-risk regions. The proportion of high-risk regions and extremely high-risk regions increased from 17.82% and 16.63%in 2000 to 18.10% and 16.76% in 2015, respectively. And the risk level in the main urban areas was significantly higher than that in the southeastern and northeastern areas of Chongqing. The centroids of all grades of risky areas presented a successive distribution from west to east, and the centroids of high-risk and extremely high-risk regions shifted eastward. From 2000 to 2015, the centroids of highrisk and extremely high-risk reg

关键词： geographic information system(GIS) agricultural non-point source pollution(ANSP) risk assessment kernel density Chongqing China

Classification of Growth Clubs and Convergence: Evidence from Panel Data in China, 1981-2004

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China & World Economy 2007年第5期15卷 91-106页

作者： Wei Zou Hao Zhou Professor Institute for Advanced Study （IAS） the School of Economics and Management Wuhan University Wuhan China Assistant Professor Jinan University Guangzhou China

This paper uses provincial panel data to examine club convergence in China during 1981- 2004. We estimate the province-specific initial technology level, A（O）, and classify the Chinese economy into ＂developed club＂ and ＂underdeveloped club ＂ based on the economic characteristics of A（O）, instead of on geographical location. We find significant evidence of conditional convergence across provinces, and that the convergence speed in the developed club is faster than that in the underdeveloped club. We also find that.＂（i） human capital accumulation contributes more than physical capital does to club convergence,＂（ii） there is a positive correlation between infrastructure and growth convergence at the national level and within the developed club, while the spillover effect of infrastructure has not been developed in the developing club; and （iii） the effect of economic openness on convergence is tiny, and insignificant across and within clubs.

关键词： club convergence kernel density initial technology level

本地非农就业、外出务工与中国农村收入不平等

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农业经济研究