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401.
Xingwen Wu Subhash Rakheja Huichao Wu Sheng Qu Pingbo Wu Huanyun Dai 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(6):914-934
High magnitude impact loads caused by polygonal wear of the wheels have been associated with in-service failures of structural components of high-speed railways, although the mechanisms leading to wheels’ polygonalisation is not yet fully understood. In this study, a long-term field test programme is undertaken and the data are analysed to gain better understanding of the growth in polygonal wear, and its characteristics and correlation with the axle box acceleration. The field measurements on a high-speed railway involved monitoring of wheels profiles between successive re-profiling of the wheels so as to identify the rate of growth of wear in addition to the axle box acceleration. The data suggested rapid growth in wheel wear, which could be characterised by polygonal wear of nearly 18th and 19th harmonic order. It is further shown that the magnitude of axle box acceleration increased considerably with increasing wear magnitude of the wheel. 相似文献
402.
船舶交通流预测的准确性和可靠性已成为制约港口经济科学发展的瓶颈因素。文章综合利用小波变换的局部化性质与神经网络的自学习能力,并引入灰色模型以反映船舶交通流的发展趋势,使得小波神经网络在灰色模型预测结果的基础上结合船舶交通流的影响因素再预测,构成基于灰色小波神经网络的船舶交通流组合预测模型。实验结果表明,灰色小波神经网络的预测精度高于BP神经网络与小波神经网络,提高了整个预测系统的精度及其鲁棒性。 相似文献
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In order to improve the security and reliability for autonomous underwater vehicle (AUV) navigation, an H∞ robust fault-tolerant controller was designed after analyzing variations in state-feedback gain. Operating conditions and
the design method were then analyzed so that the control problem could be expressed as a mathematical optimization problem.
This permitted the use of linear matrix inequalities (LMI) to solve for the H∞ controller for the system. When considering different actuator failures, these conditions were then also mathematically expressed,
allowing the H∞ robust controller to solve for these events and thus be fault-tolerant. Finally, simulation results showed that the H∞ robust fault-tolerant controller could provide precise AUV navigation control with strong robustness. 相似文献
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QU Zhi-ying ZHANG Xing-zhou 《船舶与海洋工程学报》2005,4(4):59-64
Joint power control has advantages of multi-user detection and power control;and it can combat the multi-access interference and the near-far problem. A novel adaptive joint power control algorithm with channel estimation in a CDMA cellular system was designed. Simulation results show that the algorithm can control the power not only quickly but also precisely with a time change. The method is useful for increasing system capacity. 相似文献
409.
随着航运业的不断发展,船用柴油机排放污染物也已成为日趋严重的污染源。本文综述了船用柴油机排气中NOx、SOx.颗粒物、HC和COx等的后处理方法和技术,重点介绍NOx和SOx的净化技术.最后展望了船用柴油机排气控制技术的发展方向。 相似文献
410.
Thebraintypecreatinekinaseisoenzyme(CK BB)incerebrospinalfluid(CSF)hadcloserelationswithheadinjury ,whichhadattractedpeople’satten tion[1] .However,therewerefewstudiesaboutthedi agnosisonheadinjuryvalueofCK BB ,andprogno sis .Inordertostudythediagnosisandprogn… 相似文献