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The similarity transformation model between different coordinate systems is not accurate enough to describe the discrepancy of them.Therefore,the coordinate transformation from the coordinate frame with poor accuracy to that with high accuracy caanot guarantee a high precision of transformation.In this paper,a combined method of similarity tranformation and regressive approximating is presented.The local error accumulation and distortion are taken into consideration and the precision of coordinate system is improved by using the recommended method. 相似文献
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尼尔基、丰满水库分别为松花江流域两源嫩江和第二松花江干流上的控制性工程,两水库的联合运用对松花江流域(哈尔滨以上)水资源调配意义重大。选取尼尔基和丰满入库年径流系列,采用Copula函数构建了尼尔基和丰满水库来水的联合概率分布模型,并对其丰枯同步和异步频率进行了分析。结果表明:两库丰枯异步频率(60.78%),明显大于丰枯同步频率(39.22%),说明来水条件总体有利于开展水库联合运用;同时,对水库联合运用作用不大的情况(丰丰、丰平、平丰、平平)发生频率为40.92%,有利于水库发挥联合运用效益的情况(丰枯、枯丰、平枯、枯平)发生频率为43.16%,不利情况(同枯)发生频率为15.92%,由于发生不利情况可能性不低,且发生后会对流域供水产生较大影响,因此在水库兴利联合调度方案制定中应认真考虑。 相似文献
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