Talking hypothetically: the Duhem–Quine thesis, multiple hypotheses and the demise of hypothetico-deductivism     

M. Morad 《Geoforum》2004,35(6):661-668

The positivism-inspired hypothetico-deductive method has dominated research practices in geographical sciences for several decades. Notwithstanding its significant contribution, as a widely employed protocol, there is a growing recognition that positivist methods of analysis have failed to accommodate the countless auxiliary assumptions that underlie any geographical research hypothesis, not only in human geography but also in physical geography and geographical information science. The Duhem–Quine thesis has received a significant amount of attention in recent years in scientific and logical theory circles, as a progressive alternative to the hypothetico-deductive method. The thesis’s main attraction to contemporary practitioners of science is that it allows methodologically rigorous ways of resolving inconsistencies between a theoretical system and experience. Under the Duhem–Quine thesis, the use of a multiple organisation of hypotheses in geographical research will militate against an over-dependence on the null-hypothesis which is inconsistent with the fact that conclusions in geographical research are subject to contingent factors such as human participation, measurement error, and ecological fallacies.  相似文献   

Study of the primary cosmic radiation mass composition near the “knee” from EAS data     

E.G. Boos  D.T. Madigozhin 《Astroparticle Physics》1998,9(4):311-324

A string-decay cascade phenomenological model that conservatively extrapolates accelerator data has been adapted to cosmic ray-air collisions. Monte Carlo simulations of extensive air showers (EAS) initiated by primary protons and nuclei have been performed. The best agreement between the predictions of this model and experimental data on spectra of electron sizes (N_e) for vertical incidence at different altitudes is found for a heavy mass composition of the cosmic rays (above the “knee” energy).  相似文献   

多层电流片中双撕裂模的耦合   总被引：2，自引：2，他引：0       下载免费PDF全文

王传兵  王水 《地球物理学报》1998,41(5):591-600

应用边界层理论研究了多层电流片中m≥2的双撕裂模的耦合发展行为．在一阶近似下,解析求得了环位形中撕裂模的外区匹配参数Δ,所得结论对撕裂模的线性和非线性发展均有意义．结果表明,两有理面模之间的耦合总是使双撕裂模更不稳定．耦合的强度不仅与两有理面之间的距离和平衡状态有关,而且与模在两有理面发展的相对强弱有关．两有理面相距愈远,耦合相对愈弱;发展强的有理面处的模对另一有理面处的模影响更大．本文用所得结论对双撕裂模的初始非统性发展行为进行了分析．多层电流片中撕裂模不稳定性引起的自发重朕,可能对太阳耀斑、日冕加热、太阳风和磁层耦合等有重要影响．  相似文献   

奇异值分解方法对降水的预测试验   总被引：5，自引：4，他引：5  

张万诚  解明恩 《高原气象》2002,21(1):102-107

SVD方法由于可以用来研究两个气象场的相互作用，本文将其与多元回归方法结合作短期气候预测试验，并用它对云南5月雨量与海温进行分解，客观地反映出海洋和大气的耦合关系，所选高相关区的预报因子物理意义清晰，并与多元回归模型进行了预测效果比较，从所作的6年预报试验和2年独立预报检验结果来看，效果较好，值得进一步研究应用。  相似文献   

Assessing environmental impacts of urban growth using remote sensing     

John Trinder  Qingxiang Liu 《地球空间信息科学学报》2020,23(1):20-39

ABSTRACT

This paper provides a study of the changes in land use in urban environments in two cities, Wuhan, China and western Sydney in Australia. Since mixed pixels are a characteristic of medium resolution images such as Landsat, when used for the classification of urban areas, due to changes in urban ground cover within a pixel, Multiple Endmember Spectral Mixture Analysis (MESMA) together with Super-Resolution Mapping (SRM) are employed to derive class fractions to generate classification maps at a higher spatial resolution using an Artificial Neural Network (ANN) predicted Wavelet method. Landsat images over the two cities for a 30-year period, are classified in terms of vegetation, buildings, soil and water. The classifications are then processed using Indifrag software to assess the levels of fragmentation caused by changes in the areas of buildings, vegetation, water and soil over the 30 years. The extents of fragmentation of vegetation, buildings, water and soil for the two cities are compared, while the percentages of vegetation are compared with recommended percentages of green space for urban areas for the benefit of health and well-being of inhabitants. Changes in Ecosystem Service Values (ESVs) resulting from the urbanization have been assessed for Wuhan and Sydney. The UN Sustainable Development Goals (SDG) for urban areas are being assessed by researchers to better understand how to achieve the sustainability of cities.  相似文献   

参数化的多次散射激光雷达方程和它的反演理论 Ⅰ:方程     

邱金桓  H.Quenzel  M.Wiegner 《大气科学》1992,(5)

本文提出了一个参数化的多次散射激光雷达方程,该方程基于本文引出的四个因子,即几何消光因子、消光分布因子、前向散射因子和后向散射因子.前两个因子表征多次散射成分对大气消光系数分布、激光的发散角和接收视场角以及接收孔径的依赖关系,后两个因子表征多次散射成分对散射相函数的依赖关系.这个参数化多次散射雷达方程在241个数值试验中得以检验,这些试验包含很宽的大气条件和雷达几何参数,包括14个大气散射相函数,均匀和不均匀的大气消光系数分布,0.5至1之间变化的一次散射反照率,地基和空间站激光雷达两种情形.数值试验表明,在小于4的光学厚度内参数化的解和Monte-Carlo解之间的标准偏差小于27％,而本模式的计算时间比Monte-Carlo方法偏小4个数量级左右.本模式不仅适合于研究多次散射对激光回波信号和激光大气遥感的效应,而且对于考虑多次散射的激光大气探测而言,是一个合适的应用模式.  相似文献   

南黄海北部5.3级地震前青岛地电的短临异常     

张昭栋  王晋生 《内陆地震》1993,7(4):344-349

多年来的观测表明,青岛地电的主要干扰因素是地下水位和温度。它们对地电的影响并不是简单的线性关系,而是带有滞后记忆效应的非线性关系。为了较好地消除地下水位和温度的影响,我们采用了非线性的褶积滤波方法,同时采用多元回归法。对地电资料进行综合处理。处理后的地电3个分向的资料都在震前11～12天开始出现明显的短临异常,3个分向的资料的一阶差分曲线也在震前11～12天出现明显的短临异常。  相似文献   

用褶积滤波及多元回归方法处理聊古—1井氮氦比观测资料   总被引：4，自引：0，他引：4  

张昭栋  高玉斌 《地震研究》1993,16(3):260-266

聊古-1井位于聊城——兰考断裂带北段。自1981年以来对该井氮氦比每日进行观测,其主要干扰因素为降雨和井水流量。其中降雨对氮氢比观测的影响不是简单的线性关系,而是带有滞后记忆效应的非线性关系。为此,我们采用了非线性的褶积滤波的方法,来处理降雨对氮氦比的影响。为了消除井水流量变化对氮氦比的影响,同时采用了多元回归的方法,对氮氦比观测值进行综合处理。在以上处理的基础上,分析了1981年宁晋地震和1983年菏泽地震前,氮氦比的变化特征。两次地震前的2个月左右,氮氦比值都出现了明显地高值异常,且均在异常转折、恢复的过程发震。所以这一规律可做为该井氮氦比地震短期前兆异常指标。  相似文献   

一个考虑地形影响的三维中尺度Monte-Carlo多源模式   总被引：3，自引：0，他引：3       下载免费PDF全文

邓玉珍  雷孝恩  田瑞明 《气象学报》1993,51(2):139-147

本文设计了一个考虑地形、湍流统计量垂直非均匀和非平稳过程影响的三维中尺度Monte-Carlo多源模式。模式模拟了珠海地区大气SO_2浓度时空分布,很好地揭示了由海陆风和山谷风控制下浓度的日变化规律,计算与实测浓度之间平均比值为0.94±0.2388,其结果是令人满意的。本模式具有概念清楚,没有作人为的特别假设和数值解平流扩散方程时出现的伪扩散问题,更能反映湍流扩散本身具有随机性这一本质的优点。  相似文献   

甚高频多普勒多气球跟踪系统          下载免费PDF全文

向明  任阵海  邹孝恒 《大气科学》1993,17(3):349-358

一个多路径传输误差小、造价低、重量轻的甚高频多普勒多气球跟踪系统已研制完成.本文对其原理、设计和性能作了概述.该系统在珠江三角洲观测实验中取得了40km双气球平飘轨迹和30km内水平扩散参数,为中距离低空大气污染物输送、扩散的拉氏轨迹和大气污染模式研究提供了一个新的探测手段.  相似文献