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101.
102.
Cellular automata (CA) have proven to be very effective for simulating and predicting the spatio-temporal evolution of complex geographical phenomena. Traditional methods generally pose problems in determining the structure and parameters of CA for a large, complex region or a long-term simulation. This study presents a self-adaptive CA model integrated with an artificial immune system to discover dynamic transition rules automatically. The model’s parameters are allowed to be self-modified with the application of multi-temporal remote sensing images: that is, the CA can adapt itself to the changed and complex environment. Therefore, urban dynamic evolution rules over time can be efficiently retrieved by using this integrated model. The proposed AIS-based CA model was then used to simulate the rural-urban land conversion of Guangzhou city, located in the core of China’s Pearl River Delta. The initial urban land was directly classified from TM satellite image in the year 1990. Urban land in the years 1995, 2000, 2005, 2009 and 2012 was correspondingly used as the observed data to calibrate the model’s parameters. With the quantitative index figure of merit (FoM) and pattern similarity, the comparison was further performed between the AIS-based model and a Logistic CA model. The results indicate that the AIS-based CA model can perform better and with higher precision in simulating urban evolution, and the simulated spatial pattern is closer to the actual development situation. 相似文献
103.
提出了一种利用多尺度几何特征向量的变化检测方法,其基本原理是基于多尺度影像分割将变化检测从传统的像素光谱空间转换到对象尺度空间,利用多尺度分割形成的几何特征向量进行变化检测。以陕西省渭南市为研究区域,使用本方法检测该区域2002~2009年的地表覆盖变化。从变化检测结果可以看出,本文方法的检测效果优于其他传统检测算法。 相似文献
104.
Antonio Pedrera Jesús Galindo‐Zaldívar Antonio Ruiz‐Bustos José Rodríguez‐Fernández Ana Ruiz‐Constán 《第四纪科学杂志》2009,24(6):581-592
The NW–SE shortening between the African and the Eurasian plates is accommodated in the eastern Betic Cordillera along a broad area that includes large N‐vergent folds and kilometric NE–SW sinistral faults with related seismicity. We have selected the best exposed small‐scale tectonic structures located in the western Huércal‐Overa Basin (Betic Cordillera) to discuss the seismotectonic implications of such structures usually developed in seismogenic zones. Subvertical ESE–WNW pure dextral faults and E–W to ENE–ESW dextral‐reverse faults and folds deform the Quaternary sediments. The La Molata structure is the most impressive example, including dextral ESE–WNW Neogene faults, active southward‐dipping reverse faults and associated ENE–WSW folds. A molar M1 assigned to Mimomys savini allows for precise dating of the folded sediments (0.95–0.83 Ma). Strain rates calculated across this structure give ~0.006 mm a?1 horizontal shortening from the Middle Pleistocene up until now. The widespread active deformations on small‐scale structures contribute to elastic energy dissipation around the large seismogenic zones of the eastern Betics, decreasing the seismic hazard of major fault zones. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
105.
本文就定点符号法表示点状分布事物数量特征的三种连续比率符号和非比率分级符号进行了较深刻的分析与比较,指出了它们各自的特点和适用条件,并结合实例提出了如何改进和正确运用的方法。文中对定点符号如何表示两种相关内容的数量特征也结合实际作了具体分析。 相似文献
106.
Estradiol treatment during early life stages of tiger puffer Takifugu rubripes induces feminization in genetic males.However,the ovaries in genetic males may revert to testes once estradiol treatment is halted.Therefore studies should investigate molecular mechanisms underlying ovary-to-testis recovery in genetic males after treatment.In the present study,tiger puffer were exposed to 10,and 100μg/L 17β-estradiol(E 2)from 15 to 100 days post-hatching(dph),then gonad phenotypes and expression profi les of six sex-related genes(cyp19a,foxl2,dmrt1,amh,sox9a,and sox9b)were characterized after the exposure.Results showed that both 10 and 100μg/L E2 induced ovarian development in genetic males at 100 dph.However,all ovaries induced by 10μg/L E2 first developed into intersexual gonads and subsequently reverted to testes after the exposure.As for treatment of 100μg/L E2,while the rest of the ovaries maintained morphological stability,percentages of intersexual gonads reached 38%-57%,and none were reverted to testes.Increased mRNA levels of cyp19a,foxl2 and sox9b and decreased mRNA levels of dmrt1,amh,and sox9a were observed during the ovarian development in genetic males.While contrary gene expression profiles were detected during ovary-to-testis transformation.The mRNA levels of all the six genes were increased during the development of intersexual gonads.These results indicated that up-regulation of dmrt1,amh and sox9a is associated with initial ovary-to-intersexual transformation,and suppression of foxl2,cyp19a and sox9b is essential for complete ovary-to-testis recovery in genetic males.This research will help to trace the molecular processes underlying gonadal transformation in teleosts. 相似文献
107.
����ǿ��ǰ���ϵ��������TEC�쳣�����о� 总被引:2,自引:0,他引:2
???????GPS??TEC???????VTEC???????????15?????????????????ο????????????????????VTEC???? 2006??12??26??????????????7.2???????2008??5??12????8????????????????????????????8???????????????????????????????????????????????????????????????????VTEC????????????????????????????????VTEC?????????????????????????????????????????????????????? 相似文献
108.
基于人工免疫算法的数据压缩技术在滑坡异常提取中的应用研究 总被引:1,自引:0,他引:1
滑坡异常信息提取对滑坡预测预报至关重要。以四川丹巴滑坡为例,应用人工免疫算法对滑坡镜2、镜6和镜9的位移监测数据进行压缩,分别获得最优压缩率为0.821,0.819,0.829,保真度为0.95。并在置信水平为0.95的条件下,对压缩后数据进行异常提取,分别获得了3个监测点的4个异常信息。这些异常信息所反映的滑坡变形发展演化规律与滑坡声发射等其他监测信息所反映的规律基本保持一致,说明应用人工免疫算法对滑坡位移监测数据进行压缩处理可以在保持原有数据的特性与规律的同时,有效除去监测数据中的冗余与不相关信息,增加有效数据密度,有利于准确提取滑坡异常信息。 相似文献
109.
模式时间关联误差对集合平方根滤波估算土壤湿度的影响 总被引:2,自引:1,他引:1
为了定量评估模式时间关联误差对NOAH陆面模式同化表层土壤湿度观测估算土壤湿度廓线的影响,采用集合平方根滤波(En SRF)与状态增广相结合的技术,开展同时更新状态变量和订正模式偏差的观测系统模拟试验,结果表明:同化时若不对存在较大系统性偏差的模式时间关联误差进行处理,En SRF就不能有效估算土壤湿度廓线,而采用状态增广和En SRF相结合的技术,可以在更新土壤湿度时同步订正模式偏差,土壤湿度估算精度明显提高。敏感性试验进一步表明:模式偏差大小、同化时间间隔和观测误差会以不同方式对同化结果造成影响。 相似文献
110.
自2001年中国加入世界贸易组织(WTO)后,产品多元化日益成为中国企业发展的重要策略。当前关于企业产品多元化的研究忽视了外部影响因素的作用。论文利用中国海关贸易数据库,探讨了地方出口产品结构对企业出口产品多元化的影响。研究发现:① 地方产品结构会影响企业的产品多元化模式。所处地方的产品不相关多元化程度越高,企业的产品不相关多元化程度越高;所处地方的产品相关多元化程度越高,企业的产品相关多元化程度也会越高。② 由于产品知识来源的差异,生产不同产品企业的产品多元化模式受地方产品结构的影响不同。例如,比起交通运输设备制造企业,鞋帽制造企业的产品(不)相关多元化受地方出口产品的(不)相关多元化的促进作用更强。③ 内、外资企业的产品多元化模式受地方产品结构的影响存在差异。这可能是因为内、外资企业联系程度不同,所以地方出口产品(不)相关多元化对内资企业产品(不)相关多元化的促进作用比对外资企业的作用更强。 相似文献