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71.
Denis H.?NomiyamaEmail author Tsugukiyo?Hirayama 《Journal of Marine Science and Technology》2003,8(2):88-98
The importance of ocean waves parameters (propagation direction, mean period, significant wave height, etc.) is related to several aspects of a ships safety, efficiency in operation, routing, design, and maintenance. However, some available methods for obtaining those parameters have data limitations and inconvenient aspects. In severe weather conditions, an ocean-wave-field detector is necessary. This can provide two-dimensional ocean-wave-field information directly. Among other conventional methods, ship-borne wave radar has the ability to function as such a detector, and some researchers have tried to develop practical systems. A numerical approach using plan position indicator (PPI) images from conventional marine radars is proposed to retrieve valuable information from the ocean waves. A three-dimensional Fourier transform is applied to a set of consecutive radar PPI images to perform spectrum analysis. The removal of undesired elements in the spectrum is achieved by applying a hi-pass filter to remove static components, and by comparing the data with the expected dispersion shell to correct for nonocean-wave power. Numerical experiments under controlled conditions using simulated PPI images were performed through numerical simulations based on theoretical ocean-wave equations. The results include a comparison between the original wave parameters used in the simulation and the values retrieved from the spectrum analysis. 相似文献
72.
Authors Index
Author Index Volume 30 2003 相似文献73.
Xinlian?XieEmail author Dong-Ling?Xu Jian-Bo?Yang Jin?Wang Jun?Ren Shijun?Yu 《Journal of Marine Science and Technology》2008,13(1):50-62
A method is presented for selecting a preferred ship from a group of candidates as a reference ship for a new design. The
method is based on a recently developed approach for multiple-criteria decision analysis under uncertainty, the evidential
reasoning approach. Using this method, both quantitative and qualitative attributes of a complicated nature can be considered
in the selection process. The method consists of three phases: identifying suitable candidate ships, evaluating them in terms
of both conventional techno-economical and qualitative attributes, and aggregating all the attributes using the evidential
reasoning approach. This three-phase procedure is illustrated by means of an oil tanker selection example. The results of
this study show that the evidential reasoning approach can support multiple-criteria ship selection processes when both qualitative
and quantitative information with or without uncertainties have to be taken into account. The outcomes generated by the method
include the ranking of the candidate ships and indications of their strengths and weaknesses in the format of performance
distributions over different assessment grades. Such information is vital in helping decision makers to make an informed selection
and be aware of any risk implication associated with the selection. 相似文献
74.
The application of social marginal cost pricing (SMCP) in PPP's in the railway sector faces several challenges. We examine in detail the practical applicability of SMCP in railway PPPs from the perspectives of cost accounting and effectiveness of SMCP towards the allocative efficiency goal, addressing the likely drawbacks in conciliating the welfare objectives of SMCP with the objectives of project financing (cost recovery) and value for money that justify the realization of PPP's. To this end, we combine theoretical analysis with the observation of empirical results of a case study. We split the analysis per type of private service provision, which can be for service operation or infrastructure management. For infrastructure management, we recommend splitting the operator remuneration and the track access charges. For service operation, we argue that the correct decision on source of funding of the service operator should depend on the characteristics of the contract. 相似文献
75.
Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for ... 相似文献
76.
正自适应AUTOSAR为实现车辆ECU软件的更大灵活性打下了坚实的基础。这些系统是可扩展的,是全自动和联网驾驶方向的重要一步。自适应AUTOSAR不是替代经典AUTOSAR,它的优势在于2种标准的巧妙结合。自动驾驶对车辆内部E/E架构提出了更高要求。自动驾驶功能需要越来越强大的控制单元,且越来越多地相互联网,并与基础设施(如云端系统)联网(图1)。通过使用来自各种车辆传感器以及外部(例如高精确地图资料)的数据,软件可创 相似文献
77.
Sloshing is relevant in several applications like ship tanks, space and automotive industry and seiching in harbours. Due to the relationship between ship and s... 相似文献
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79.
In this study, the coupled torsional-transverse vibration of a propeller shaft system owing to the misalignment caused by the shaft rotation was investigated. T... 相似文献
80.