共查询到18条相似文献,搜索用时 171 毫秒
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SOTDMA在船载AIS中的应用 总被引:3,自引:0,他引:3
分析了自组织时分多址接续(SOTDMA)技术在船载自动识别系统(AIS)中的应用。通过硬件设计和软件编程,实现了SOTDMA的时隙划分、时隙同步和访问。 相似文献
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基于Winsock的AIS系统仿真研究 总被引:2,自引:0,他引:2
就如何应用Winsock对AIS系统进行仿真的具体实现进行了阐述,且对实现过程中如何解决时隙同步问题进行了分析。设计的这套仿真系统可以为今后AIS相关技术研究提供试验平台。 相似文献
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针对风机叶轮射流尾迹与蜗舌产生的动静干涉流场的特性,研究风机内部动静干涉流场的相互作用机制.以某离心风机为研究对象,通过对传统蜗舌的结构进行改进,在叶轮出口长度对应的蜗舌展向长度范围内开槽,采用数值计算的方法分析开槽结构的槽宽、槽深和间距等参数对离心风机的气动特性和风机内部流场分布的影响规律.计算结果表明:开槽蜗舌有助于改善风机的运行效率,减小尾迹对蜗舌前缘的冲击,延缓蜗舌下游边界层的流动分离,削弱叶轮与蜗舌之间的动静干涉作用,抑制蜗壳壁面的非定常压力脉动. 相似文献
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高效率、高转矩密度特性使得永磁电机已被广泛应用于舰船推进领域,然而永磁电机的齿槽转矩却降低了电机的性能。永磁电机齿槽转矩受多个电机参数的影响,这些参数与电机齿槽转矩之间存在非线性关系,通过参数优化来削弱齿槽转矩成为永磁电机齿槽转矩研究的重点。提出一种基于粒子群算法的永磁电机齿槽转矩优化方法,该方法选择对齿槽转矩影响较大的极弧系数、永磁体厚度和定子槽宽度3个参数为优化变量,以齿槽转矩峰值最小为优化目标,在对永磁电机齿槽转矩解析模型进行变形和简化的基础上,使用粒子群算法对解析模型进行参数优化,得到最优参数组合,并用有限元方法进行验证。结果表明,经该优化方法优化后,电机的齿槽转矩大幅降低。 相似文献
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集装箱船配载过程中的重要环节是合理的箱位分配,它对保证集装箱船装载后的航行性能及其码头装箱效率有重要的影响.随着集装箱船的大型化及待装船箱量的增加,该问题的求解较为困难.结合集装箱船配载中箱位分配的实际操作特点,提出了利用与禁忌算法相结合的混合蚁群算法来求解集装箱的箱位分配问题.仿真模拟试验表明该算法能够在不影响装箱难度的同时,大幅提高集装箱装船后船舶的航行性能. 相似文献
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为指导轮缘推进器(RDT)水动力学设计,借助CFD方法,对RDT各主要几何特征对其水动力性能影响开展研究。首先,验证CFD数值方法分析RDT水动力特性的有效性;然后,基于CFD研究RDT水动力性能的各主要影响因素,主要包括导管的长径比、扩散比、导管收缩比和桨叶梢径比。结果表明:RDT最佳长径比随载荷系数递增,并趋于一极限值,相比于导管扩散比和收缩比,导管长径比因素更能主导RDT的设计优化;RDT最佳扩散比随载荷系数递减,并趋于一极限值,最佳扩散比随长径比递减;RDT的收缩比对水动力性能影响不及扩散比和长径比显著,最佳收缩比随载荷系数呈线性递增,随长径比递减;RDT的最佳梢径比随载荷系数递增,无毂RDT比有毂RDT具有更小的最优梢径比。研究结果可为轮缘推进器的水动力学设计和优化提供参考。 相似文献
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Market concentration on the major container shipping routes has the potential to reduce contestability, impede effective competition and, as a consequence, inhibit the positive relationship between trade and economic growth. This development could also hamper the ability of economic regions to realize their respective competitive and comparative advantages. Within this context, the structure-conduct-performance (SCP) framework is used to analyse liner shipping dynamics in the transpacific, Europe-Far East and transatlantic trade routes. The analysis finds no conclusive evidence that either the increased concentration of slot capacity or the attempts by shipping lines to boost potential slot capacity (mainly through collaborative arrangements) lead to improved financial performance. The paper concludes that, despite high and increasing concentration among carriers on each of the trade routes analysed, these markets remain contestable. 相似文献
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Market concentration on the major container shipping routes has the potential to reduce contestability, impede effective competition and, as a consequence, inhibit the positive relationship between trade and economic growth. This development could also hamper the ability of economic regions to realize their respective competitive and comparative advantages. Within this context, the structure-conduct-performance (SCP) framework is used to analyse liner shipping dynamics in the transpacific, Europe–Far East and transatlantic trade routes. The analysis finds no conclusive evidence that either the increased concentration of slot capacity or the attempts by shipping lines to boost potential slot capacity (mainly through collaborative arrangements) lead to improved financial performance. The paper concludes that, despite high and increasing concentration among carriers on each of the trade routes analysed, these markets remain contestable. 相似文献