Alternative Fuzzy Cluster segmentation of remote sensing images based on Adaptive Genetic Algorithm

Remote sensing image segmentation is the basis of image understanding and analysis. However, the precision and the speed of segmentation can not meet the need of image analysis, due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm (AGA) and Alternative Fuzzy C-Means (AFCM). Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased, and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means (FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.     

Errors and correction of precipitation measurements in China

In order to discover the range of various errors in Chinese precipitation measurements and seek a correction method, 30 precipitation evaluation stations were set up countrywide before 1993. All the stations are reference stations in China. To seek a correction method for wind-induced error, a precipitation correction instrument called the ＂horizontal precipitation gauge＂ was devised beforehand. Field intercomparison observations regarding 29,000 precipitation events have been conducted using one pit gauge, two elevated operational gauges and one horizontal gauge at the above 30 stations. The range of precipitation measurement errors in China is obtained by analysis of intercomparison measurement results. The distribution of random errors and systematic errors in precipitation measurements are studied in this paper. A correction method, especially for wind-induced errors, is developed. The results prove that a correlation of power function exists between the precipitation amount caught by the horizontal gauge and the absolute difference of observations implemented by the operational gauge and pit gauge. The correlation coefficient is 0.99. For operational observations, precipitation correction can be carried out only by parallel observation with a horizontal precipitation gauge. The precipitation accuracy after correction approaches that of the pit gauge. The correction method developed is simple and feasible.     

中国地震台网震级的对比

采用线性回归和正交回归方法,利用中国地震台网1983-2004年的观测资料,对中国地震局地球物理研究所测定的地方性震级ML、面波震级MS与MS7、长周期体波震级mB、短周期体波震级mb进行对比,给出了它们之间的经验关系式.研究结果表明:①由于不同的震级标度反映了地震波在不同周期范围内辐射地震波能量的大小,因此对于不同大小的地震,使用不同的震级标度更能客观地描述地震的大小.当震中距小于1 000 km时,用地方性震级ML可以较好地测定近震的震级.当地震的震级M＜4.5时,各种震级标度之间相差不大.当4.5＜M＜6.0时,mB＞MS,MS标度低估了较小地震的震级,因此用mB可以较好地测定较小地震的震级.当M＞6.0时,MS＞mB＞mb,mB与mb标度均低估了较大地震的震级,用MS可以较好地测定出较大地震(6.0＜M＜8.5)的震级.当M＞8.5时,MS出现饱和现象,不能正确地反映大地震的大小;②在我国境内,当震中距＜1 000 km时,ML与区域面波震级MS基本一致,在实际应用中无需对它们进行震级的换算;③虽然MS与MS7同为面波震级,但由于所使用的仪器和计算公式不同,MS比MS7系统地偏高0.2～0.3级;④对于长周期体波震级mB和短周期体波震级mb,虽然使用的计算公式相同,但由于使用的地震波周期不同,对于mB=4.0左右的地震,mB与mb几乎相等,而对于mB≥4.5的地震,则mB＞mb.     

差分GPS方法在城市活断层探测中的应用探讨

使用差分GPS方法, 测量西宁盆地内部各级阶地参数, 对比野外阶地特征, 探讨区域新构造时期活动特征, 以及西宁城市周缘活断层的分布及活动特征。 通过这一区域的实践, 认为DGPS方法能够快速、 精确的获得区域内阶地面的坐标和高程, 是确定弱活动或隐伏断裂的可行方法。 南川河断裂错断T₃、 T₄、 T₅阶地, 断裂的活动时间为T₃阶地形成后, T₂级阶地形成前的0.10 Ma B.P.至0.05 Ma B.P.。 垂直断距15～20 m, 最小垂直活动速率约为0.30 mm/a。     

水分和养分供应对凹凸棒石复配苔藓结皮生长的影响

为了评价生物固沙材料在不同水分和养分供应条件下的应用效果,对沙漠苔藓结皮和含凹凸棒石固沙材料的叶绿素和生长进行了研究。结果表明：人工培养苔藓结皮与固沙材料的最佳配比为1∶1,由接种在沙面上的生物固沙材料的叶绿素a含量、强度和厚度决定。凹凸棒石显著提高了接种生物固沙材料的强度、叶绿素a含量和厚度。3种养分供应方式和3种模拟干旱区的间歇供水方式均能显著提高人工生物型结皮的厚度和强度。50%的养分处理是最佳的养分供应方式。接种生物固沙材料在隔天供水条件下具有较高的厚度和强度。较短的供水和养分供应间歇有利于沙漠生物结皮的生存和繁殖。     

鄂尔多斯盆地天环坳陷北段奥陶系烃源岩特征及成熟演化史

为研究天环坳陷北段下古生界天然气成藏规律,利用探井资料和有机地球化学方法,评价了天环坳陷北段奥陶系烃源岩特征并恢复其成熟演化史。天环坳陷北段奥陶系乌拉力克组和克里摩里组烃源岩有机碳含量和生烃潜量相对较高,烃源岩有机质丰度以中等—好为主,少部分为差烃源岩;三道坎组和桌子山组烃源岩以差为主。干酪根组分鉴定表明,天环坳陷北段奥陶系烃源岩主要为Ⅱ₁～Ⅰ型干酪根,热演化程度高,处于生干气阶段。成熟演化史模拟显示,古生代—中生代早期地温梯度低,地层埋藏浅,烃源岩成熟演化程度低。燕山期,由于构造热事件,地温梯度迅速升高,早白垩世烃源岩经历的最高温度超过200℃,达到生气高峰期,早白垩世是油气成藏的主要时期。早白垩世之后,鄂尔多斯盆地整体抬升,地温梯度减小,生烃作用停止。     

最近十年来中国地理科学的进展

最近十年来中国地理科学的最重要进展有:自然地理学与人文地理学的平衡发展,人口、资源、环境的研究,遥感的应用与地理信息系统的建立,自然地理定位观测,青藏高原隆起对自然环境的影响,城市与城市规划,中国历史地理研究等。最近,并已开始研究气候变化与海平面上升对中国的影响,使我国地理科学研究紧紧跟上世界发展的步伐。     

ON SOME KEY SEDIMENTATION PROBLEMS OF THREE GORGES PROJECT (TGP)

I. INTRODUCTIONThe Three Gorges Project (TGP) being planned is to be located on the Yangtze River at Sandouplug, 44 km upstream of Yichang (Fig. l). A scheme studied in the feasibility stage has the crest ofthe dam placed at 185 m with a maximums height o…     

山东招远—掖县地区金矿床的矿物分带

根据控矿构造与主矿化阶段的矿物共主组合及其在金矿床空间上的分布规律,可将招掖地区金矿床的矿物分带分为正向垂直分带和逆向分带。金矿床中的黄铁矿晶体特征具有明显的分带。     

Symmetric Stability of Rotation and Boussinesq Fluid in Bounded Domain by Using Normal Mode Method

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