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ABSTRACTThe wavelet analysis technique was combined in this study with the projection pursuit autoregression (PPAR) model, and a new mid- and long-term runoff forecasting model, the wavelet analysis-based PPAR (PPAR-WA) is proposed, which realizes runoff forecasting from the perspective of the internal mechanism of a sequence. The runoff forecasting of the leading hydropower station in the Li Xianjiang cascade reservoirs in China was carried out to test the performance of the proposed model, and the accuracy and stability of the forecasting results were evaluated and analysed. The results show that the average relative error of the forecasting period can reach 9.6%, and the best relative error is less than 5% in some years. In addition, compared with PPAR, a back-propagation neural network and autoregression moving average model through three evaluation indexes, the results of PPAR-WA have higher accuracy and stronger stability. So, it has a certain value of popularization and application. 相似文献
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ABSTRACTA new improved shuffled frog leaping algorithm (SFLA), the chaos catfish effect SFLA (CCESFLA), is proposed by coupling a local “refine search” mechanism and a “global incentive adjustment” mechanism. Chaotic technology is introduced in the local “refine search” mechanism to improve local search ability, by implementing more refined local search around the optimal individuals. The catfish effect mechanism is adopted in the “global incentive adjustment” mechanism to improve global convergence, by motivating the frogs to “jump out” of the local steady state. The operation optimization by the CCESFLA is carried out taking the Li Xianjiang cascade reservoirs in China as an example. Compared with SFLA, particle swarm optimization, immune SFLA and cloud SFLA, the average annual power generation using the CCESFLA can be increased by 6.7, 7.5, 3.0 and 0.8%, respectively. The convergence process of the CCESFLA is more stable, and its execution time is the least of the three improved SFLAs. 相似文献
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由于被动式超低频电磁探测仪具有便携易用、野外布线简单、受地形影响小并且对低阻体、高阻体均有反映的特点,因此在能源勘探、资源勘察和地质构造探测中展现出良好的性能与开发潜力,接收来自地下深部的天然源超低频电磁信号的勘探技术,已成为国内外近些年来的研究热点。文中首先介绍了被动式超低频电磁探测技术最近几年的野外试验情况及超低频磁场传感器的主要技术指标水平,认为目前BD-6型被动式超低频电磁探测仪无论在频谱分辨率、信噪比,还是在探测效率方面都得到了极大提高;其次,分析了场源效应、频深转换公式、分辨率因素对数据采集、处理过程的影响;提出场源效应导致的随机噪声可以通过多次采集数据叠加平均方法加以降低,利用已知地质和钻井资料修正后的频深转换公式更适用于某种勘探目标(煤层气、地下水等)和某个地区探测数据的解释;采用适当的线性(谱分析法)和非线性(分数维法)分析方法,可以为探测数据的处理与解释提供新的方法和技术途径。 相似文献
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利用陵县1962-2005年雷暴观测资料，分析了陵县雷暴天气的气候变化特征、雷暴天气的发生背景等。发现：陵县的雷暴日数年际变化大，存在减少的趋势；汛期6-8月为雷暴高发期。 相似文献
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Cen Jingyi Wang Jianyan Huang Lifen Ding Guangmao Qi Yuzao Cao Rongbo Cui Lei L&#; Songhui 《中国海洋湖沼学报》2020,38(3):722-732
Journal of Oceanology and Limnology - On May 24–29, 2019, a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish (Plectorhinchus cinctus and... 相似文献
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水文地质参数在含水层压密过程中不断变化,这是诸多地面沉降模型实际应用中的难点之一。就含水层压密对水文地质参数的影响开展了初步的实验,结果表明,压密前后含水层的渗透系数和给水度发生了较大的变化。其中：渗透系数随模拟含水层介质压密过程的变化几乎呈线性的减小趋势,线性拟合决定系数为0.959 2~0.997 1;给水度随着含水层的压实而表现出下降的趋势较为复杂,随介质类型的不同而有差异。渗透系数和给水度的下降速度在不同介质中也有一定的差异。在本研究的实验模型尺度下,给水度和渗透系数呈现一定的线性正相关关系,一次线性相关函数斜率为0.001 3~0.005 1,截距为0.011 6~0.038 1,基本相近且在相同数量级。 相似文献
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中海达HD5800G一体化蓝牙RTKGPS测量系统的诞生推动我国国产GPS行业整体水平向国际水平靠拢。阐述了本单位使用中海达GPS系列HD5800G一体化蓝牙RTK测量系统应用于国土系统测绘中的优点及注意的问题。 相似文献
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