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Traditional agroecosystem transition in mountainous area of Three Gorges Reservoir Area

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Journal of Geographical Sciences 2020年第2期30卷 281-296页

作者： liang xinyuan LI Yangbing SHAO Jing’an RAN Caihong School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area Chongqing 401331China

The Three Gorges Reservoir Area(TGRA)is typical of an ecologically vulnerable area,comprised of rural and mountainous areas,and with high *** of its economic and ecologic importance,studying the traditional agroecosystem changes in the TGRA is key to rural development and *** this study,we apply a framework of theoretical analysis,empirical study,and trend prediction to the Caotangxi River watershed within the *** QuickBird high-resolution remote sensing images from 2012 to 2017 to evaluate natural resources and farmers’behavior,we analyze the transition and trends in the traditional agroecosystem in mountainous areas of the TGRA at spatial scale of the man-land *** find that the agroecosystem in the TGRA can be divided into four modes using 100 m interval buffer rings:high-low-low,high-low-high,low-high-low and low-low-high mode where the different modes represent the agricultural development stages in the ***,the traditional agroecosystem in TGRA,represented by system elements such as farmers and sloping farmland,is transforming to accommodate the diversification of farmer *** example,sloping farmland,which was dominated by a production function,now has equal emphasis on ecological and economic ***,the range of the agroecosystem transition has migrated beyond high mountain areas to flat valley ***,this study provides an overview of land use in rural areas,controls on soil and water loss in mountainous areas,and better rural living environments in the TGRA.

关键词： Three Gorges Reservoir Area ecologically fragile area mountainous area traditional agroecosystem transition empirical study spatial scale

Spatiotemporal features of farmland scaling and the mechanisms that underlie these changes within the Three Gorges Reservoir Area

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Journal of Geographical Sciences 2019年第4期29卷 563-580页

作者： liang xinyuan LI Yangbing School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area Chongqing 401331China

Discussions regarding the functional transformation of agricultural utilization and the mechanisms that underlie these changes within the Three Gorges Reservoir Area(TGRA)reflect variati ons in the relati on ship betwee n people and their environme nt in China's central and wester ns part,an area of mountains and reservoirs.A clear understa nding of these changes also provides the scientific basis for the development of multi-functional agriculture in typical mountainous *** counties were selected for analysis in this study from the hinterland of the TGRA;we analyzed changes in farmland scaling and corresponding under?lying mechanisms by defining the concepts of“Scaling Farmland”(SF)and by using the software packages ArcGIS10.2,SPSS,and Geographical *** results of this analysis show that sources of increased SF have mainly comprised cultivated and shrub *** deed,with the excepti on of some alpine off-season vegetables,SF growth has mainly occurred in low altitude areas and in places where the slope is less than 30°.We also show that spatial changes in various SF types have also been substantially different,but in all cases are closely related to road and township administrative *** factors at the patch level,including elevation and slope,have contributed significantly to SF,while at the township level,underlying socioeconomic and humanistic factors have tended to include road traffic and agricultural population *** contrast,at the region al level,underlying driving forces within each have tended to be more significant than overall study area *** show that while changes in,and the development of,SF have been driven by numerous factors,agri?cultural policies have always been amongst the most *** results clearly elucidate general land use transformation patter ns within the mountain regi ons of western China.

关键词： Three Gorges Reservoir Area functional transformation of agricultural land scaling farmland spatiotemporal features underlying driving forces

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正态模糊因果图的推理算子及归一化算法研究

仪器仪表学报 2008年第2期29卷 414-419页

作者：梁新元重庆工商大学废油资源化技术与装备教育部工程研究中心

因果图理论是一种基于概率论的推理方法。本文在分析因果图理论发展和存在问题的基础上,将模糊数学引入因果图理论,即模糊因果图,从而可以克服因果图分析中概率难以精确赋值的缺点,将因果图理论应用扩大到了模糊领域。本文主要对事件概... 详细信息

因果图理论是一种基于概率论的推理方法。本文在分析因果图理论发展和存在问题的基础上,将模糊数学引入因果图理论,即模糊因果图,从而可以克服因果图分析中概率难以精确赋值的缺点,将因果图理论应用扩大到了模糊领域。本文主要对事件概率为正态模糊数进行讨论,提出了因果图的模糊算子,得到了模糊条件概率的计算公式,提出了正态模糊数的归一化算法。最后,以核电站的一个子系统为例进行仿真实验,实验结果实际一致。研究表明:模糊因果图能有效地用于故障分析,比原来的因果图方法具有更大的灵活性和适应性。

关键词：因果图模糊事件概率正态归一化

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因果图理论用于煤矿机械设备故障分析的研究

计算机工程 2005年第5期31卷 204-206,209页

作者：梁新元重庆工商大学计算机科学与信息工程学院

因果图理论是一种基于概率论的图形化的知识表达推理方法,文中对因果图理论在故障分析和安全评估中的应用进行了研究。将这种新方法运用于煤矿机械设备的故障分析,并与故障树分析法进行了比较和分析。研究结果表明因果图方法比故障树分... 详细信息

因果图理论是一种基于概率论的图形化的知识表达推理方法,文中对因果图理论在故障分析和安全评估中的应用进行了研究。将这种新方法运用于煤矿机械设备的故障分析,并与故障树分析法进行了比较和分析。研究结果表明因果图方法比故障树分析法效果好。

关键词：因果图方法煤矿机械没备故障分析可靠性

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因果图在重大安全事故分析中的应用

计算机工程 2005年第13期31卷 174-175,197页

作者：梁新元重庆大学自动化学院

将最小割集和最小径集的概念引入了因果图理论,并用于重大安全事故的定性和定量分析中。以煤矿行业为应用背景,通过最小割集、最小径集和事件对顶事件的概率影响,分析了各事件对瓦斯爆炸的影响,并在此基础上提供了事故预防方案。研究表... 详细信息

将最小割集和最小径集的概念引入了因果图理论,并用于重大安全事故的定性和定量分析中。以煤矿行业为应用背景,通过最小割集、最小径集和事件对顶事件的概率影响,分析了各事件对瓦斯爆炸的影响,并在此基础上提供了事故预防方案。研究表明:因果图方法能有效地用于安全分析,是预测重大安全事故的定性和定量方法,并能为事故原因调查、事故预防措施提供有效的方案。采用因果图方法对煤矿瓦斯爆炸进行安全分析的结果与实际一致,在此基础上提出的预防措施比较有效。

关键词：因果图方法安全事故分析瓦斯爆炸最小割集最小径集

China's food security situation and key questions in the new era:A perspective of farmland protection

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Journal of Geographical Sciences 2022年第6期32卷 1001-1019页

作者： liang xinyuan JIN Xiaobin HAN Bo SUN Rui XU Weiyi LI Hanbing HE Jie LI Jin School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Key Laboratory of Coastal Zone Exploitation and Protection Ministry of Natural ResourcesNanjing 210023China Natural Resources Research Center Nanjing UniversityNanjing 210023China Wuhan Planning and Research Institute Wuhan 430014China Pinggang Middle School Shenzhen 518116GuangdongChina

As the world’s largest developing country,the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors(e.g.,transformed supply channels,tightening international situation and frequent emergencies)in recent years and has attracted extensive attention from the academic community subject to multiple *** study uses literature review,statistical analysis,and spatial analysis methods to systematically explore China’s food security situation in the context of farmland resource *** is found that the demand-side pressures such as demographic changes,social class differentiation,and dietary structure adjustments derived from economic growth and rapid urbanization have placed extremely high expectations on food ***,the quantitative restrictions,utilization ways,and health risks of farmland resources on the supply side constitute a huge hidden concern that affects the stability of food *** China’s farmland protection system is undergoing a transition from focusing on quantity management to sustainable use,the matching and coordinating demand pressure and supply capacity for food security is ***,facing uncertain future development scenarios,policymakers should focus on building a resilient space for China’s farmland protection to withstand the interference of major *** existing farmland protection space policy can be integrated by establishing a national farmland strategic reserve system(based on resilient space),and further development of targeted use control measures for zoning,grading,and classification will help realize sustainable China’s farmland resources use.

关键词： food security systematical analysis key questions farmland protection resilient space China

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三峡库区规模农地时空变化特征及其驱动机制

地理学报 2018年第9期73卷 1630-1646页

作者：梁鑫源李阳兵重庆师范大学地理与旅游学院重庆401331 三峡库区地表过程与环境遥感重庆市重点实验室重庆401331

探讨库区农地利用的转型及其机制,可反映中西部结合带、山区、库区的农村变化和人与环境关系的变化,为典型山区的农业多功能转型发展方向提供科学依据。选取三峡库区腹地5个区县为研究区,通过定义"规模农地"相关概念,利用Arc GIS 10.2... 详细信息

探讨库区农地利用的转型及其机制,可反映中西部结合带、山区、库区的农村变化和人与环境关系的变化,为典型山区的农业多功能转型发展方向提供科学依据。选取三峡库区腹地5个区县为研究区,通过定义"规模农地"相关概念,利用Arc GIS 10.2软件并结合SPSS、地理空间探测器等技术手段对规模农地的变化与机制进行分析。研究发现:规模农地的转移来源主要由耕地和灌木林地组成,除部分高山反季节蔬菜,规模农地的增长一般发生在低海拔地区,且在坡度30°范围内均有分布;不同类型的规模农地空间变化有所不同,但均与道路和乡镇级行政中心的关系明显。斑块水平上,高程、坡度等自然因素对规模农地的贡献相对较大;乡镇水平上以道路交通、农业人口密度等社会经济与人文因素驱动力为主;区域水平上,各区县的驱动因子影响力较研究区整体尺度更为显著。规模农地的变化与发展受多种因素驱动,但农业政策始终是各驱动因素的主导,不同水平的行为主体会促使规模农地发展趋向不同的方向,但原则上均受国家农业发展现状与政府政策导向影响。

关键词：三峡库区农地功能转型时空变化特征驱动机制

基于降阶模型的中子扩散特征值问题的不确定性分析研究

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原子能科学技术 2023年第8期57卷 1584-1591页

作者：梁鑫源王毅箴郝琛哈尔滨工程大学核安全与仿真技术国防重点学科实验室黑龙江哈尔滨150001 清华大学核能与新能源技术研究院先进反应堆工程与安全教育部重点实验室北京100084

为提高基于抽样统计的堆芯物理不确定性分析效率,将本征正交分解(POD)法与伽辽金(Galerkin)投影法相结合,研究了基于POD-Galerkin方法的降阶模型在堆芯物理不确定性分析中的应用可行性。以二维两群TWIGL基准题为研究对象,在各物质区群... 详细信息

为提高基于抽样统计的堆芯物理不确定性分析效率,将本征正交分解(POD)法与伽辽金(Galerkin)投影法相结合,研究了基于POD-Galerkin方法的降阶模型在堆芯物理不确定性分析中的应用可行性。以二维两群TWIGL基准题为研究对象,在各物质区群常数的有限次扰动下提取堆芯通量分布的关键变化特征,将全阶中子扩散问题在各变化特征上投影以建立降阶中子扩散模型,并以该降阶模型替代全阶模型开展物质区群常数的不确定性分析。结果表明:降阶与全阶模型计算的k eff数学期望偏差接近1 pcm,并且相比于全阶模型不确定性分析所需的计算时间,将降阶模型构造所需的全阶模型计算时间考虑在内,降阶模型的分析时间仅为其11.48%,极大地提高了不确定性分析的效率。基于拉丁超立方抽样和简单随机抽样的降阶与全阶模型计算的k eff数学期望偏差均小于8 pcm,相同样本量下拉丁超立方抽样结果的误差更小。从TWIGL基准题测试结果来看,在POD-Galerkin降阶建模中,相同样本量下,更建议采用拉丁超立方抽样方法。

关键词：降阶模型本征正交分解伽辽金投影不确定性分析

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复杂因果图并行推理算法研究

计算机科学与探索 2014年第4期8卷 483-493页

作者：梁新元重庆工商大学计算机科学与信息工程学院重庆400067 电子商务及供应链系统重庆市重点实验室重庆400067

因果图的精确推理算法是NP难的,因此寻找高效的推理方法是值得研究的问题。介绍了因果关系研究进展,对经典因果图推理过程作了进一步分析,在此基础上提出了复杂因果图的并行推理算法,并对算法的时间复杂度进行了分析,最后用一个实例验... 详细信息

因果图的精确推理算法是NP难的,因此寻找高效的推理方法是值得研究的问题。介绍了因果关系研究进展,对经典因果图推理过程作了进一步分析,在此基础上提出了复杂因果图的并行推理算法,并对算法的时间复杂度进行了分析,最后用一个实例验证了算法的推理效果。研究表明,该复杂因果图并行推理算法有效地降低了时间复杂度,特别是在有环且处理机数量足够的情况下和无环且处理机有限的情况下,算法的复杂度是一个多项式时间复杂度,这为因果图提供了一种可行的新的推理方法。

关键词：复杂因果图并行推理计算时间复杂度