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111.
综合考虑系统在输入阶跃扰动和负荷扰动两个工况时的超调量、稳定时间和ITAE指标,研究了PID控制器参数寻优的问题。采用多目标遗传算法求出Pareto最优解,使用信息熵法和逼近理想解的排序方法(TOPSIS)对Pareto最优解给出了排序。计算了一艘水面船舶柴油机调速器控制的数值算例,结果表明本文方法有效,所设计的PID性能优异,可以工程实际应用。 相似文献
112.
本研究根据相似准则和试验条件设计试验模型。在试验模拟的1节悬浮隧道管段上分别布置2组和3组锚索支撑,测试在不同流速条件下,悬浮隧道管体结构的环向应变、轴向应变及张力腿锚索的轴力。根据试验结果,初步分析悬浮隧道应力的空间分布特征和张力腿的轴力情况;给出在相同环境条件下,张力腿锚索数量对结构应力的影响、洋流速度对悬浮隧道管段结构变形和张力腿轴力的影响关系等。 相似文献
113.
在公路客运枢纽方案评价过程中,涉及大量不确定因素和模糊因素。为协调这些因素,并降低人为因素的影响,采用二元对比重要性排序采确定各因素的权重,将备选方案与理想方案的几何偏差作为选优依据,为科学合理地的选择公路客运枢纽提供一种定量的方法,最后给出实例说明方法的实用性。 相似文献
114.
针对关联项具有N×N个任意未知常时滞的线性连续大系统,采用线性矩阵不等式(LMIs)方法,提出了一种分散的无记忆状态反馈二次保性能控制器的存在条件和设计方法.最后用一个示例说明分散无记忆状态反馈二次保性能控制器的设计方法. 相似文献
115.
The alternatives to the oil based fuels for transportation are considered and analysed. These are the synthetic fuels, made from coal, the liquid petroleum gases of propane and butane, compressed natural gas and methanol. The problems associated with the use of electric vehicles are discussed; the main problem being that of range. The possible use of hydrogen as a fuel is analysed in some detail. Since its supply can be tied directly to nuclear energy sources, rather than hydrocarbon feed stocks, it could be an alternative in the long term. The main problems of the storage of hydrogen on the vehicle and of its propensity to “back‐fire” into the engine intake are discussed. The first can be ameliorated and the second eliminated by dual fuelling; with petrol. It is advocated that the on‐board storage of hydrogen be by the use of hydrides for private cars. However, it is expected that it may be as liquid hydrogen for some forms of transport and will certainly be in this form for aircraft. 相似文献
116.
This paper concerns the development of a new decision support framework for the appraisal of transport infrastructure projects. In such appraisals there will often be a need for including both conventional transport impacts as well as criteria of a more strategic and/or sustainable character. The proposed framework is based on the use of cost-benefit analysis featuring feasibility risk assessment in combination with multi-criteria decision analysis and is supported by the concept of decision conferencing. The framework is applied for a transport related case study dealing with the complex decision problem of determining the most attractive alternative for a new fixed link between Denmark and Sweden – the so-called HH-connection. Applying the framework to the case study made it possible to address the decision problem from an economic, a strategic, and a sustainable point of view simultaneously. The outcome of the case study demonstrates the decision making framework as a valuable decision support system (DSS), and it is concluded that appraisals of transport projects can be effectively supported by the use of the DSS. Finally, perspectives of the future modelling work are given. 相似文献
117.
Traditionally, the design of mooring lines and risers of floating production systems (FPS) has been performed separately, by different teams, employing uncoupled analysis tools that do not consider the nonlinear interaction between the platform hull and the mooring lines and risers. Design processes have been focused on fulfilling the design criteria of the respective component (mooring/riser) alone, with few or no consideration to the other component, and little interaction between the design teams. Nowadays the importance of employing analysis tools based on coupled formulations is widely recognized, and analysis strategies have been proposed to consider feedback between mooring lines and risers within their respective design processes.In this context, this work details a proposal of one single and fully integrated design methodology for mooring systems and risers for deep-water FPS. In this methodology, the design stages of both risers and mooring lines are incorporated in a single spiral, allowing the full interaction of different teams; mooring design implicitly considers the riser integrity, and vice-versa, leading to gains in efficiency and cost reduction.Different analysis strategies are employed, taking advantage of uncoupled and coupled numerical models. The models generated at the initial/intermediate design stages can be reused in subsequent stages: simpler models are used in the initial stages, and more refined models are gradually introduced, to reach an ideal balance between computational cost and accuracy of results. In the advanced stages, the exchange of information between mooring/riser also allows the definition of criteria for the selection of governing/critical loading cases to be revised and verified in detail. This leads to the reduction of the original loading case matrix, allowing a feasible use of time-consuming fully coupled analysis.Results of a case study illustrating the application of some of the main processes of the methodology are included. 相似文献
118.
阐述了船坞超高型管柱支撑的设计。提出了船坞区域搭载时管子支撑与外板3种连接形式下的支撑设计允许承载力的理论计算,并对目前船坞使用的φ426mm×14mm和φ500mm×18mm两种管子进行计算分析。改进了撑管的底部支撑,提高了超高型管子支撑的使用效果和安全性。 相似文献
119.
This paper investigates the performance of a policy decision tool proposed for multi-objective decision under different policy interventions. This tool deals with the trade-off between mobility and equity maximization under environmental capacity constraints. Two system objectives, maximization of mobility and equity, are formulated in terms of the sum of total car ownership and number of trips, and the differences in accessibility between zones. Environmental capacities are based on production efficiency theory in which the frontier emission under maximum system efficiency is taken as environmental capacity. To examine the performance of the proposed model, three types of hypothetical policies (network improvement, population increase and urban sprawl) are formulated. Effects are simulated using data pertaining to Dalian City, China. Results show that the proposed model is capable of representing the trade-offs between mobility and equity based on different policy interventions. Compared with two extreme cases with the single objective of mobility maximization or equity maximization, the Pareto-optimal solutions provide more interesting practical options for decision makers. Taking the solution based on the maximum equity as an example, the policy of urban sprawl yields the most significant improvement in both emission and accessibility of the three scenarios. 相似文献
120.