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黑土型退化草地时空格局遥感监测 被引量:1
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作者 刘云峰 秦坤 +1 位作者 吕慧玲 陈思宇 《测绘通报》 CSCD 北大核心 2022年第11期57-61,共5页
准确及时地了解黑土型退化草地的时空分布特点,对祁连山地区草地退化修复治理具有重要意义。本文选取祁连县野牛沟乡西北部区域作为研究区,基于Landsat 8 OLI影像,结合地理国情监测成果,尝试利用分场景的决策树分类方法提取黑土型退化... 准确及时地了解黑土型退化草地的时空分布特点,对祁连山地区草地退化修复治理具有重要意义。本文选取祁连县野牛沟乡西北部区域作为研究区,基于Landsat 8 OLI影像,结合地理国情监测成果,尝试利用分场景的决策树分类方法提取黑土型退化草地范围,并对比分析2014—2019年黑土型退化草地的时空变化特征。结果表明,多场景的决策树分类方法对黑土型退化草地监测具有很好的适用性;2014—2019年,研究区北部部分区域缓坡地和中部滩地黑土型退化问题有所好转,西部和西北部缓坡地黑土型退化问题有进一步恶化的趋势;好转草地主要以人工干预为主,恶化草地可能是受水热空洞效应、鼠害等多种因素的影响。 展开更多
关键词 黑土型退化草地 Landsat 8 OLI影像 野牛沟乡 时空格局
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A Novel Integrated Measure for Energy Market Efficiency
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作者 TANG ling lühuiling +2 位作者 YANG Fengmei YU lean lI Jingjing 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2020年第4期1108-1125,共18页
This paper formulates a novel integrated measure for energy market efficiency,by investigating different aspects of the market performance.Different from most existing models focusing on one certain aspect,the novel m... This paper formulates a novel integrated measure for energy market efficiency,by investigating different aspects of the market performance.Different from most existing models focusing on one certain aspect,the novel measure especially takes into consideration the self-similarity(or system memo ability or long-term persistence)via fractality,the attractor properties in phase-space via chaos,and disorder state of data dynamics via entropy.In the proposed method,the most popular data analysis techniques of multi-fractal detrended fluctuation analysis,correlation dimension,and sample entropy are respectively conducted on the market returns to capture the corresponding features,and the entropy weight method is then used to generate the final integrated index.For illustration and verification,the proposed measure is applied to three typical energy markets analyses.The empirical results find that natural gas market and crude oil market are much more efficient than carbon market. 展开更多
关键词 FRACTAL ENTROPY ILLUSTRATION
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