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1.
焦炭价格预测研究具有重要的理论和实践意义,本文利用卡尔曼滤波算法对焦炭价格进行预测研究。建立状态空间模型时,选取焦炭价格作为唯一的状态变量,通过每一时刻变量观测值与预测值形成的新息,不断更新和迭代,以寻求最优估测值。实证分析表明,该算法对焦炭价格的跟踪和预测效果较好。  相似文献   

2.
基于支持向量回归机的耕地保有量组合预测   总被引:1,自引:0,他引:1  
为提高耕地保有量预测精度,将灰色预测GM(1,1)模型、动力预测模型、BP网络预测模型和加权支持向量回归机预测模型相结合,建立了基于支持向量回归机的耕地保有量组合预测模型,并将其用于温州市耕地保有量预测。结果表明,该模型比任一单一预测模型精度更高,可用于耕地保有量预测。  相似文献   

3.
藏波罗花Incarvillea younghusbandii是著名的藏药之一,极具开发和研究价值,但准确预测其潜在地理分布一直是目前尚未解决的关键问题。本文结合实地调查与现有研究数据,以气候和地表覆盖为环境变量,利用Maxent模型与GIS工具,对藏波罗花在西藏地区的潜在地理分布进行预测。研究结果表明:(1)Maxent模型对藏波罗花的潜在地理分布具有较高的预测精度,ROC曲线下面积(Area under the curve,AUC),训练AUC值可达0.994,测试AUC值可达0.996;(2)土壤类型、年降水量和生长繁育期降水量是影响藏波罗花生长分布的最重要环境因子;(3)藏波罗花在西藏有广泛的适生性,雅鲁藏布江与多雄藏布河间的山谷地带、喜马拉雅山脉中段地带河谷区和喜马拉雅山东段北侧与雅鲁藏布江中游南岸相间地带是目前主要的适生区,而喜马拉雅山脉东部部分地区可能会成为藏波罗花的扩散分布区。  相似文献   

4.
Geological disasters not only cause economic losses and ecological destruction, but also seriously threaten human survival. Selecting an appropriate method to evaluate susceptibility to geological disasters is an important part of geological disaster research. The aims of this study are to explore the accuracy and reliability of multi-regression methods for geological disaster susceptibility evaluation, including Logistic Regression(LR), Spatial Autoregression(SAR), Geographical Weighted Regression(GWR), and Support Vector Regression(SVR), all of which have been widely discussed in the literature. In this study, we selected Yunnan Province of China as the research site and collected data on typical geological disaster events and the associated hazards that occurred within the study area to construct a corresponding index system for geological disaster assessment. Four methods were used to model and evaluate geological disaster susceptibility. The predictive capabilities of the methods were verified using the receiver operating characteristic(ROC) curve and the success rate curve. Lastly, spatial accuracy validation was introduced to improve the results of the evaluation, which was demonstrated by the spatial receiver operating characteristic(SROC) curve and the spatial success rate(SSR) curve. The results suggest that: 1) these methods are all valid with respect to the SROC and SSR curves, and the spatial accuracy validation method improved their modelling results and accuracy, such that the area under the curve(AUC) values of the ROC curves increased by about 3%–13% and the AUC of the success rate curve values increased by 15%–20%; 2) the evaluation accuracies of LR, SAR, GWR, and SVR were 0.8325, 0.8393, 0.8370 and 0.8539, which proved the four statistical regression methods all have good evaluation capability for geological disaster susceptibility evaluation and the evaluation results of SVR are more reasonable than others; 3) according to the evaluation results of SVR, the central-southern Yunnan Province are the highest sus-ceptibility areas and the lowest susceptibility is mainly located in the central and northern parts of the study area.  相似文献   

5.
This paper analyses the features and dynamic changes of the spatial layout of air transportation utilization among different provinces in China. It makes use of data for the airport throughput and socio-economic development of every province throughout the country in the years 2006 and 2015, and employs airport passenger and cargo throughput per capita and per unit of GDP as measures of regional air transportation utilization, which is significant for refining indicators of regional air transportation scale and comparing against them. It also analyzes the spatial differences of coupling between the regional air transportation utilization indicators and the key influencing factors on regional air transportation demand and utilization, which include per capita GDP, urbanization rate, and population density. Based on these key influencing factors, it establishes a multiple linear regression model to conduct forecasting of each province's future airport passenger and cargo throughput as well as throughput growth rates. The findings of the study are as follows:(1) Between 2006 and 2015, every province throughout the country showed a trend of year on year growth in their airport passenger and cargo throughput per capita. Throughput per capita grew fastest in Hebei, with a rise of 780%, and slowest in Beijing, with a rise of 38%. Throughput per capita was relatively high in western and southeastern coastal regions, and relatively low in northern and central regions. Airport passenger and cargo throughput per unit of GDP showed growth in provinces with relatively slow economic development, and showed negative growth in provinces with relatively rapid economic development. Throughput per unit of GDP grew fastest in Hebei, rising 265% between 2006 and 2015, and Hunan had the fastest negative growth, with a fall of 44% in the same period. Southwestern regions had relatively high throughput per unit of GDP, while in central, northern, and northeastern regions it was relatively low.(2) Strong correlation exists between airport passenger and cargo throughput per capita and per capita GDP, urbanization rate, and population density. Throughput per capita has positive correlation with per capita GDP and urbanization rate in all regions, and positive correlation with population density in most regions. Meanwhile, there is weak correlation between airport passenger and cargo throughput per unit of GDP and per capita GDP, urbanization rate, and population density, with positive correlation in some regions and negative correlation in others.(3) Between 2015 and 2025, it is estimated that all provinces experience a trend of rapid growth in their airport passenger and cargo throughput. Inner Mongolia and Hebei will see the fastest growth, rising221% and 155%, respectively, while Yunnan, Sichuan, and Hubei will see the slowest growth, with increases of 62%, 63%, and 65%, respectively.  相似文献   

6.
近年来,海南省海口市、三亚市等地人口快速增长,引起了各界对海南省承载力的担忧,需要研究制定承载力约束和经济增长需求下的人口与资源环境政策。为此,本文选取粮食产量、农产品营养成分和水资源量指标,分别定量测算承载力;采用就业弹性系数法,设定就业弹性系数和地区生产总值增长率,估算经济增长所需人口总量;利用PADIS-INT人口预测软件,设定总生育率、净迁移率等参数,预测人口变化情况。通过研究认为,2050年前海南省人口总量不会超过水土资源的承载力上限,全省总体上不存在人口过多的问题,而是存在人口不足的风险。建议海南省采取鼓励人口增长的政策措施,提升自然资源管理和国土空间治理水平,引导人口在全省均衡发展。  相似文献   

7.
埃塞俄比亚咖啡价格波动很大,因此对国家经济发展的影响不容小视,对咖啡价格进行预测具有理论和实践意义。为了分析咖啡价格波动,我们采用来自埃塞俄比亚商品交易所(ECX)记录的2008年6月25日至2017年1月5日期间咖啡日收盘价数据。在这里,咖啡价格的性质是非平稳的,我们在单个线性状态空间模型上应用卡尔曼滤波算法来预测咖啡价格的最优值,主要通过使用均方根误差(RMSE)来评估用于预测咖啡价格的算法的性能。基于线性状态空间模型和卡尔曼滤波算法,均方根误差(RMSE)为0.000016375,说明该算法性能良好,研究结果可靠。  相似文献   

8.
该文构建了一种基于空间自回归的地理元胞自动机(CA)模型——SARCA模型,该模型能够较好融合地理系统模拟中的空间自相关特性,且获取的CA参数具有明确的物理意义。以1995-2015年上海城市土地利用为案例,验证了该模型的有效性。CA参数和城市土地转化概率表明,上海市外环线对于CA参数的贡献相比其他空间变量具有压倒性优势,到外环线距离越近则土地发展为城市的概率就越大。将基于Logistic回归的CA模型(LogCA)作为比较对象,模拟同期上海全域城市土地利用变化过程。CA规则表明,SAR在赤池信息量准则(AIC)、残差的描述性统计量和空间自相关指标等方面均优于Logistic回归。同时,SARCA模型在2005年和2015年的土地利用模拟结果总体精度分别为86.3%和82.0%,均优于LogCA模型的模拟结果(总体精度分别为79.8%和76.3%)。  相似文献   

9.
青藏高原是地球的"第三极",是全球海拔最高的生物地理单元。由于其高、寒、旱的生物环境特征,高寒生态系统对气候变化和人类活动非常敏感,为全球变化研究提供了天然的实验室,一直受到国内外专家重视,是生态学和全球变化研究的热点区域。青藏高原生态学研究经历了从朴素认识到机理研究的理论升华,从生物地理格局的科学考察到生态学机理定位研究的范式转变,从个体、群落到生态系统及多学科综合研究的尺度延伸,以及从理论研究到支撑资源有效利用与可持续发展的发展轨迹。今后青藏高原生态系统研究将更加聚焦于量化辨识气候变暖和人类活动对生态系统的影响,以及高原生态系统对气候变化的反馈作用研究。加强与自然地理、环境科学和遥感技术多学科、多技术、模型融合的交叉与集成研究,服务于气候变化的适应及生态-社会系统的可持续发展。  相似文献   

10.
生态系统的健康状况所体现的脆弱性特征,已成为阻碍生态环境可持续发展的关键因素。通过综述国内外学者的相关研究,从生态系统脆弱性的内生逻辑领域出发,整理测量模型、预测方法和风险评估等方面的文献,全面掌握生态系统脆弱性的研究范畴和科学框架,并分析其研究思路及发展趋势。本文得出了以下结论:(1)生态系统脆弱性的内涵既体现自然环境脆弱性的变化,又反映出由于过度开发、工业化生产活动对生态系统造成不可逆的破坏。(2)生态系统脆弱性指标设立应以全面反映其脆弱度的本质特征为目标,包含自然、社会、经济等相关因子的指标体系。(3)生态系统脆弱性测度方法、预测及风险评估的模型种类较多,侧重点及优势各有千秋,应依据研究对象及区域生态系统脆弱性的不同表征及演化机理,采用适宜的方法进行综合、系统性地评价与预测。(4)针对区域系统特点,提出相应的风险管理对策,以及具有针对性的促进生态脆弱区域生态安全和可持续发展的政策建议。  相似文献   

11.
Evolution of river systems under the background of human activities has been a heated topic among geographers and hydrologists. Spatial and temporal variations of river systems during the 1960s–2010s in the Yangtze River Delta(YRD) were investigated based on streams derived from the topographic maps in the 1960 s, 1980 s and 2010 s. A list of indices, drainage density(Dd), water surface ratio(WSR), ratio of area to length of main streams(R), evolution coefficient of tributaries(K) and box dimension(D), were classified into three types(quantitative, structural, and complex indices) and used to quantify the variations of stream structure. Results showed that:(1) quantitative indices(Dd, WSR) presented decreasing trend in the past 50 years, and Dd in Wuchengxiyu, Hangjiahu and Yindongnan have decreased most, about 20%. Structurally, the Qinhuai River basin was characterized by significant upward R, and K value in Hangjiahu went down dramatically by 46.8% during the 1960s–2010s. Decreasing tendency in D was found dominating across the YRD, and decreasing magnitude in Wuchengxiyu and Hangjiahu peaks for 7.8% and 6.5%, respectively in the YRD.(2) Urbanization affected the spatial pattern of river system, and areas with high level of urbanization exhibited least Dd(2.18 km/km2), WSR(6.52%), K(2.64) and D(1.42), compared to moderate and low levels of urbanization.(3) Urbanization also affected the evolution of stream system. In the past 50 years, areas with high level of urbanization showed compelling decreasing tendency in quantitative(27.2% and 19.3%) and complex indices(4.9%) and trend of enlarging of main rivers(4.5% and 7.9% in periods of the 1960s–1980s and the 1980s–2010s). In the recent 30 years, areas with low level of urbanization were detected with significant downward trend in Dd and K.(4) Expanding of urban land, construction of hydraulic engineering and irrigation and water conservancy activities were the main means which degraded the river system in the YRD.  相似文献   

12.
Geographical circumstances are the fundamental background for all kinds of geopolitical events. The geopolitical environment system(GES) refers to a system that combines both physical and anthropogenic subsystems. Research on the geopolitical environment system simulation is a key to understanding the international geopolitical phenomenon. The theory of GES arose from the integration of the traditional geopolitics and earth system sciences. As an interdisciplinary system composed of many different fields, integrated reviews and a metadata study of GES are urgently needed. This paper presents a comprehensive view into the origination and advance of the GES theory. The conceptual framework of the GES is described in detail. The methodology for simulating and forecasting geopolitical events is also provided. It is proposed that the core topics of the GES science may include, but are not limited to, issues as data acquisition technologies; principles on the interactions between multiple subsystems(or factors) at different scales; evaluating and mitigating the global geopolitical risks, including the political risks, economic risks, the social risks, the environmental risks and the technological risks; and forecasting the geopolitical events with machine learning and artificial intelligence techniques.  相似文献   

13.
Land surface is of spatial-temporal heterogeneity. Terrestrial system(TS) comprehensively studies on land surface and physical regionalization objectively describes geographical zonation of the system. China has a vast area with apparent spatial variations in resources and environmental conditions, which highly influence on socio-economic development. In this paper, progress of the TS studies in China is overviewed and research priorities in the near future are prospected. Since the 1950 s, China has paid great attention to the TS study as its socio-economic development, and conducted research on physical geographical regionalization, eco-geographical regionalization and comprehensive regionalization. Along with the deepening of global change research, dynamics of TS have been highly concerned. During the studies, methodology has been developed from qualitative research of integration of experts' brainpower gradually to quantitative research based on field observation and experiments of the natural processes, including physical, chemical and biological processes, as well as application of information technology and mathematical simulation. In the near future, TS would combine with the ideology, objectives and key researches of Future Earth program, to focus on the mechanism and regional effects of interaction among land surface elements, the response of TS to global change, the quantitative recognition on regional unit boundary, and the application to TS in sustainable socio-economic development.  相似文献   

14.
本文在界定生态技术概念和生态技术识别需求的基础上,梳理了现有的技术识别的方法。目前应用于技术辨识的方法主要有德尔菲法、技术路线图、层次分析法、专利计量法和文本挖掘法。其中"德尔菲法+层次分析法"把生态技术纳入到社会经济系统中进行系统化的识别,主要是构建生态技术识别的指标体系模型,分别从技术特性、技术水平和性能、经济、社会和生态效益视角进行识别;专利计量法从客观角度出发,依据生态技术自身的特点和发展规律,对其进行识别。本文认为"德尔菲法+层次分析法"和专利计量法这两种方法结合了定性和定量技术识别的优点,应该成为开展生态技术识别的首选。  相似文献   

15.
阿富汗是中国提出的"丝绸之路经济带"和"21世纪海上丝绸之路"("一带一路")的重要国家。由于多年的战乱,阿富汗经济发展相对落后,但其拥有较为丰富的矿产资源和独特的区位优势,对中国的经济战略发展具有深远的意义。为了研究阿富汗生态经济系统的可持续发展状况,本文基于能值分析方法,构建了可持续发展评价指标体系,对阿富汗2008-2015年的能值变化进行了定量评估。结果显示,2008-2015年,阿富汗总能值从5.65×10~(22) sej增长到9.75×10~(22) sej,但不可更新资源能值占总能值使用量之比一直较低,2008年只有1.72%,这表明阿富汗本地资源没有得到有效的开发利用,经济发展非常依赖于外部资源的输入;可持续发展指数(Emergy Sustainability Index,ESI)从3.00下降至0.72,环境负荷率(Environmental Loading Ratio,ELR)从0.77上升至2.06,能值产出率(Emergy Yield Ratio,EYR)从2.31下降至1.49。以上结果表明,阿富汗资源利用不平衡,经济发展水平较低,可持续发展潜力相对较大,急需开展基础建设和合理的资源开发。  相似文献   

16.
生态退化是当前世界共同面临的问题,深刻影响着人类的可持续发展。本文以拉市海流域为研究案例,利用Logistic逐步回归模型模拟该区域的潜在植被,并将其作为区域生态退化的参考系统,进而分析该区域的实际退化程度及其分布特征。结果表明:(1)拉市海流域强人类干扰集中在拉市海坝子内,影响因子主要是道路、居民点和耕地;(2)除湖泊外,拉市海存在8种潜在植被类型,其中常绿针叶林为绝对优势群落,其他7种分别是温性草甸、草丛、滩地、常绿阔叶灌木林、落叶阔叶灌木林、温性草原和高寒草原;(3)高程和土壤平均磷含量对多种植被的潜在分布影响显著,不同的植被类型,对于环境因子具有不同的敏感性;(4)整体上,流域生态退化程度较轻,其中未退化区域占比近半数,轻度退化面积约占1/4,中度退化区集中分布在强人类干扰区,占18.64%;重度退化较少发生,面积仅占全流域面积的3.17%。  相似文献   

17.
生态文明建设的目标是实现人与自然的和谐共生。国土是生态文明建设的空间载体。土地利用的方式或行为反映土地资源集约节约利用水平,导致不同的生态环境效应,从而影响区域生态文明建设水平。本专辑"土地利用与生态文明"通过优选14篇代表性论文,从土地利用效率、土地生态演化、土地多功能权衡、土地生态系统服务和土地生态风险等方面,探讨了生态文明视域下的土地利用管理理论和方法,为形成生态文明的土地利用方式、行为和制度体系提供了实践参考。本专辑研究层次多样,文献覆盖村庄、县域、省域等多级研究尺度,山地、平原和丘陵等多种地貌类型,以及华东、华中、西北、长江经济带和日本等国内外土地利用典型地区;研究方法前沿实用,包括文献研究法、分形理论、定性比较分析、VAR模型、计量经济学方法等多学科研究方法;研究主题鲜明,聚焦当前土地利用过程中的热点话题与突出问题,对土地生态效率、空间行为特征、土地利用结构优化、生态风险评价等土地利用热点问题进行了深入探讨,其中既有对耕地撂荒、土地利用风险等当前迫切的土地利用问题的文献梳理与述评,也尝试对农村景观和生态系统的多功能进行权衡与协同分析,为破解生态文明视域下的土地利用问题提供了理论与实证依据。本专辑从现实与理念等全方面、多层次地反映了以生态文明理念指导土地利用的现实迫切性,并从方法和研究框架等方面提供了理论指导与技术支撑。最后,提出了未来生态文明视域下土地利用研究领域需重点关注的五大热点方向:土地利用结构的生态化管理、土地利用过程的生态演化机理、土地生态利用模式、土地生态安全格局预警与调控、土地利用行为的生态化管控。  相似文献   

18.
绿色发展已经成为旅游产业可持续发展的重要理念和有效方式,开展旅游业绿色发展研究将有助于推进区域生态文明建设与旅游地绿色可持续发展。本文采用系统综述方法,通过回顾旅游业绿色发展历程,将我国旅游业的绿色发展划分为2个阶段:可持续发展理念下的萌芽探索阶段、绿色发展理念下的起步发展阶段。此外,文章从旅游业绿色发展的部分重要研究方法、绿色发展概念内涵辨析、绿色发展评价指标体系、绿色发展效率测度及其影响因素、绿色发展法规标准、绿色发展模式、企业绿色发展对策等方面对旅游业绿色发展进行较为系统地综述,指出我国旅游业绿色发展的积极探索对发展中国家的借鉴意义,并发现大多数研究主要以定性研究为主、定量分析为辅,相关理论体系尚未形成。因此,今后的研究应不断深化研究内容,丰富研究方法,从而构建理论体系。  相似文献   

19.
生态系统利用强度成倍的增加使得生态系统服务与居民需求间的矛盾日益严峻。"一带一路"倡议的提出对老挝生产生活带来了极大的影响,科学评估生态系统服务消耗是探究居民对生态系统影响程度的重要手段。本研究通过收获指数和料肉比等参数对老挝1961–2013年农产品、水果和畜产品消费数据进行转换,分析得到了以下结论:(1)老挝以农田、森林、草地生态系统服务消耗为主,其中农田生态系统服务消耗占比超过80%且有下降趋势,森林生态系统服务消耗占比高于10%且有上升趋势,草地生态系统服务消耗占比不足2%且基本不变,三类生态系统服务消耗量均呈现出先增加、后波动、再增加的变化趋势;(2)老挝生态系统服务消耗在1961–2008年期间形成了"农田生态系统服务消耗一家独大"模式,在2008–2013年期间形成了"农田、森林和草地生态系统服务消耗均衡发展"模式,并且有从前一个模式向后一个模式转变的趋势;(3)老挝生态系统服务消耗模式形成及变化受供给和贸易的影响,老挝在1961–2008年期间以发展农业为主,形成了"农田生态系统服务消耗一家独大"的模式;得益于农、林、畜产品进口种类的不断丰富、贸易额的增长、进口量的增加,2008年后老挝生态系统服务消耗从"农田生态系统服务消耗一家独大"模式转变为"农田、森林和草地生态系统服务消耗均衡发展"模式。本研究为生态系统服务消耗研究提供了实证参考。  相似文献   

20.
Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the "life quality theory". Based on the mechanisms governing the interactions between rural settlement space and life quality, this study examines how to optimize the spatial organization of rural settlements. Three aspects are evaluated – the integration of rural settlement spatial functions, optimization of spatial structure, and regulation of spatial scale – with the objective of building an optimization mode and framework for the spatial organization of rural settlements with high life quality. Our results suggest the following:(1) The settlement is the spatial carrier of life quality, which is an essential settlement component, and these two aspects influence and improve each other. Therefore, reasonable rural settlement space is an important precondition for higher life quality.(2) The spatial function types of rural settlements can be divided into those that maintain livelihoods, develop industry, and upgrade life quality. Optimizing spatial organization of rural settlements based on life quality requires promoting the maintenance of livelihood, integration of industrial development, and implantation in quality improvement.(3) There are two important components of optimizing the spatial organization of rural settlements. One is promoting the organic concentration of living, agricultural, and industrial spaces, the reasonable distribution of social intercourse, recreational, and services spaces, and the organic balance of living, production, and ecological spaces, so as to reasonably optimize the combination of internal spatial types in settlements. The other is forming a functional structure level of a "comprehensive village–featured village" and building spatial organization settlement modes connected by rural roads by relocating and adjusting the function of villages. These changes would require the destruction of underdeveloped villages, retaining normal villages, enlarging important villages, and constructing new villages.(4) As an ideal mode for optimizing rural settlements space based on life quality, the Rural Road-Oriented Development Model(RROD model) should be built at a rational scale for unit settlement and distance between settlements, leading to a fully functional RROD system with rational structure, auxiliary facility, and well-organized distribution.  相似文献   

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