卫星高度计应用研究现状分析

文章介绍了卫星高度计的历史沿革,应用领域及发展概况。     

基于非线性理论的海上平台空调机组振动预测与减振研究

基于非线性振动理论,建立振动预报方法.通过对空调机组振动的测试与分析,找出了该机组振动的主要激励源和有关影响因素.进而提出了具有针对性的改进措施和增加隔振器的方法,消除结构之间的半刚性连接,改变了海洋平台整体结构的固有频率,使之远离共振区域,取得了明显的减振效果.并通过现场勘探测量和计算,验证了振动分析方法.     

海上石油平台空调设备特点的探讨

从分析海上石油平台的特殊环境着手,探讨了平台空调设备的特点,提出了海上石油平台空调设备应具备的性能．     

里海远洋渔船无人机舱系统研究

针对我国远洋渔船装备落后、操纵性差、机舱环境恶劣、电站管理水平低、劳动强度大以及渔船机舱自动化水平低等问题,介绍里海远洋渔船无人机舱系统的设计与组成。通过采用主机遥控系统、电站功率管理系统、机舱监测报警系统以及网络通信等技术,将自动化、电气化、信息化和智能化控制技术等船舶前沿科技应用于实船,构建一个满足法国船级社(BV)机舱自动化最高等级AUT-UMS要求的无人机舱系统,以提高远洋渔船的操控性、安全性和可靠性,提升供电系统自动化管理水平,改善作业人员工作环境。对该自动化系统的效果和特点进行分析,结果可为我国远洋渔船自动化系统的研究提供策略和思路。     

改进的BP神经网络在船舶与海洋工程中的应用研究

人工神经网络作为一个具有高度非线性映射能力的计算模型,在工程中具有广泛的应用前景.在数值预测方面,它不需要预选确定样本的数学模型,仅通过学习样本数据即可以进行预测.文章介绍了BP神经网络,并针对实际应用中收敛速度慢,平台效应等问题对网络进行了改进并优化,详尽地给出了改进的三层BP神经网络数值预测算法.为测试该算法.选用了著名的XOR(异或)问题和和一个高度非线性的0-1矩阵预测问题对其进行了验证.计算结果表明文中算法能给出令人满意的精度.最后结合船舶与海洋工程的两个实际问题,探讨了利用改进的BP神经网络进行数值预测的方法和应该注意的问题,并给出了一些有益的建议.实践表明,文中给出的改进的BP神经网络数值预测算法值得在船舶与海洋工程中加以应用并推广.     

海洋平台锚泊定位系统特殊工况的发生条件及应对方法

特殊工况是锚泊定位系统由于锚索断裂或恶劣海况影响,导致定位精度漂移或位置失控的一种状态。这种状态是正常可控方式和非正常失控状态的时域渐变。文章对这种工况的演变过程断面提出了扩大偏差的弱稳定控制模式,延缓离散的不稳定控制模式,应急释放的设备保全控制模式。通过调整控制策略阻断恶化过程,或者延展这种不断恶化的时间过程,为人员和关键设备的安全保护争取更有效的时间。     

Altimeter assimilation in the OCCAM global model: Part I: A twin experiment

An altimeter data assimilation scheme has been tested in the OCCAM (Ocean Circulation and Climate Advanced Modelling) global 1/4°, 36-level model using a twin experiment format. The Cooper and Haines displacement scheme is used. The method works well in most regions and depths. Currents and densities in the top 1000 m generally improve by over 50–70% after 5 months of sea level assimilation every 15 days. Below 1000 m, an error reduction of up to 50% is achieved. The errors remain low during a further 60-day run without assimilation. Diagnostics for the North Atlantic, the Tropical Pacific and the Antarctic Circumpolar Current are shown alongside the global averages.The main problems encountered were in weakly stratified regions of the Antarctic and Arctic seas. A scale selective filter is developed to avoid assimilating scales much larger than the local deformation radius, and this avoids the adverse assimilation effects in the southern oceans. A companion paper uses this scheme to assimilate TOPEX and ERS-1 altimeter maps.     

基于BP神经网络的船舶水压场信号检测

船舶水压场信号总是淹没在大量的海浪杂波中,为了有效地从背景干扰中检测船舶水压场信号,文章籍海浪水压场近似服从正态分布的特性,在对接收到的海浪水压场信号进行AR建模的基础上,提取模型的自回归系数作为特征向量,采用BP神经网络进行信号检测。通过仿真数据对该检测方法进行验证,结果表明该方法简单而且易于实现,在低信噪比条件下,也能够达到较高的检测率。     

外置式液压蓄能鱼雷发射装置缩比模型假海试验方案仿真分析

为研究及探索外置式液压蓄能鱼雷发射装置关键技术,根据相似准则,按照1:3的比例设计了该装置的缩比模型假海试验方案,并做了仿真分析。仿真结果显示,该方案能较好地反映原型机的内弹道性能。在确定相似准则后,还可以根据具体实际需要,选择不同的比例系数进行缩比模型试验。本文为外置式液压蓄能鱼雷发射装置缩比模型假海试验提供了理论依据。     

Impact of phytoplankton community size on a linked global ocean optical and ecosystem model

We isolated the effect phytoplankton cell size has on varying remote sensing reflectance spectra (R_rs(λ)) in the presence of optically active constituents by using optical and radiative transfer models linked in an offline diagnostic calculation to a global biogeochemical/ecosystem/circulation model with explicit phytoplankton size classes. Two case studies were carried out, each with several scenarios to isolate the effects of chlorophyll concentration, phytoplankton cell size, and size-varying phytoplankton absorption on R_rs(λ). The goal of the study was to determine the relative contribution of phytoplankton cell size and chlorophyll to overall R_rs(λ) and to understand where a standard band ratio algorithm (OC4) may under/overestimate chlorophyll due to R_rs(λ) being significantly affected by phytoplankton size. Phytoplankton cell size was found to contribute secondarily to R_rs(λ) variability and to amplify or dampen the seasonal cycle in R_rs(λ), driven by chlorophyll. Size and chlorophyll were found to change in phase at low to mid-latitudes, but were anti-correlated or poorly correlated at high latitudes. Phytoplankton size effects increased model calculated R_rs(443) in the subtropical ocean during local spring through early fall months in both hemispheres and decreased R_rs(443) in the Northern Hemisphere high latitude regions during local summer to fall months. This study attempts to tease apart when/where variability about the OC4 relationship may be associated with cell size variability. The OC4 algorithm may underestimate [Chl] when the fraction of microplankton is elevated, which occurs in the model simulations during local spring/summer months at high latitudes in both hemispheres.