不确定性在动态船队规划模型研究中的应用

通过分析传统船队规划问题,提出了利用鲁棒优化来建立不确定条件船队规划模型,在验证模型有效性时将已知概率的情景结合描述需求的不确定性,最后通过与需求确定情况相比较,说明本文的设计使得船队规划具有模型和解双重鲁棒性。     

Strategic fleet size planning for maritime refrigerated containers

In the present economic climate, it is often the case that profits can only be improved, or for that matter maintained, by improving efficiency and cutting costs. This is particularly notorious in the shipping business, where it has been seen that the competition is getting tougher among carriers, thus alliances and partnerships are resulting for cost effective services in recent years. In this scenario, effective planning methods are important not only for strategic but also operating tasks, covering their entire transportation systems. Container fleet size planning is an important part of the strategy of any shipping line. This paper addresses the problem of fleet size planning for refrigerated containers, to achieve cost-effective services in a competitive maritime shipping market. An analytical model is first discussed to determine the optimal size of an own dry container fleet. Then, this is extended for an own refrigerated container fleet, which is the case when an extremely unbalanced trade represents one of the major investment decisions to be taken by liner operators. Next, a simulation model is developed for fleet sizing in a more practical situation and, by using this, various scenarios are analysed to determine the most convenient composition of refrigerated fleet between own and leased containers for the transpacific cargo trade.     

一种混合优化的全局路径规划算法

针对全局路径规划研究中遗传算法存在搜索范围广而导致收敛速度慢的问题,本文提出一种混合优化的全局路径规划方法,完成对图像读取、处理后使用A*算法预处理缩小可行区域从而提高收敛速度。所提出的混合优化规划方法主要优化遗传算法的初始种群,在不影响最终路线的情况下,缩小初始种群的搜索范围,提高算法进行全局路径规划的速度,快速有效的规划出全局路线。另外本文给出一种评价体系对规划结果进行定量的避障评价,评价结果能够以数值形式对规划结果进行综合评价,评价结果显示通过混合优化算法规划出的路径具有更佳的安全性。     

虚拟目标算法在舰队协作中的应用

在海上军事领域,对上空导弹的精确定位﹑跟踪及打击是舰船制导领域重要的研究方向。同时,由于定位跟踪的目标有多个,需要舰队间协作,进行航路规划对多弹协同的弹道进行预测,其本质是一个多目标规划非线性问题。虚拟目标算法采用二维建模,多弹的路径规划引入条件约束,是解决弹道路径定位跟踪的有效算法。本文在分析海上导弹飞行能力﹑路径约束条件的基础上,利用虚拟算法设计导弹多目标的跟踪算法,最后给出了仿真结果。     

Multi-period liner ship fleet planning with dependent uncertain container shipment demand

This paper deals with a realistic multi-period liner ship fleet planning problem by incorporating stochastic dependency of the random and period-dependent container shipment demand. This problem is formulated as a multi-period stochastic programming model with a sequence of interrelated two-stage stochastic programming (2SSP) problems characterized ship fleet planning in each single period. A solution method integrating dual decomposition and Lagrangian relaxation method is designed for solving the developed model. Numerical experiments are carried out to assess applicability and performance of the proposed model and solution algorithm. The results further demonstrate importance of stochastic dependence of the uncertain container shipment demand.     

水面舰艇编队对潜搜索效能评估模型

  目的  为提高搜索到目标潜艇的概率,更有效地开展水面舰艇编队搜潜行动,对舰艇应召搜潜路径规划问题进行研究。  方法  首先,构建基于隐式马尔科夫模型（HMM）框架的水面舰艇应召搜潜模型,设计两阶段启发式求解的方法,使搜潜命中概率期望值最大,利用进化算法（EA）,通过对种群内的个体进行交叉和变异操作,避免出现局部最优的问题,并与常规搜潜方法进行对比;然后,通过实验研究不同分割策略对路径优化的影响。  结果  单舰搜潜和多舰搜潜的仿真实验表明,采用所提方法能够获得最大化搜潜命中概率期望值以及最优搜潜路径。而分割次数的实验表明,合理的重新划分搜潜区域,有利于找到总体更优的搜潜路径。  结论  该模型能找到最优搜潜路径,有效提高水面舰艇编队搜潜效率。     

混合粒子群优化算法求解船队规划非线性模型研究

船队规划是非常复杂的决策,会受到很多因素的影响,客观、科学的得到优化结果非常重要。本文在线性模型的基础上,考虑船舶航速,并将船舶航行时间、成本等因素作为约束条件建立船队规划非线性模型,然后通过混合粒子群优化算法进行模型求解,最后进行仿真实验。实验结果表明,本文算法能够合理的规划船舶发展,并且船舶的限制率低。     

区域目标搜索中基于改进RRT的UAV实时航迹规划

  目的  为了解决无人艇编队在智能航行时全局路径规划与局部自主避碰问题,提出基于改进快速搜索随机树(RRT)算法的无人艇编队路径规划技术。  方法  针对无人艇编队形状稳定问题,在RRT算法扩展环节提出一种非严格保形修正向量与非严格保形控制圆区域,使搜索树有朝着严格保形坐标点生长的趋势;针对突发障碍物与非严格保形规划点碰撞问题,在RRT算法碰撞检测环节提出可调节避碰圆区域与障碍物修正向量,使无人艇安全避碰并最大程度地保持队形稳定。  结果  结果显示,无人艇编队在该算法作用下表现出了良好的保形性能,并能对突发障碍物进行有效的避碰。  结论  该算法效能高、稳定性强、路径规划质量高,在实际工程应用中具有重要的意义。     

舰载无人机自动着舰动力学建模及控制算法

无人机在各个领域的应用已经越来越广泛。相比起传统的飞机,无人机不仅制造成本低,而且能够完成一些传统飞机无法完成的任务,比如远程侦测和军事打击等。但是无人机的发展和更大规模的应用仍然受到起飞和着舰技术的限制。自主轮式是未来发展的主要方向,此种方式的关键是自动控制算法的先进性和精确性。本文将在自主轮式的基础上,建立无人机起飞和着舰的数学模型,然后充分研究其动力学特性和控制算法。     

A dynamic model for marginal cost pricing of port infrastructures

ABSTRACT

A dynamic model for marginal cost pricing of port infrastructures links costs to system performance by combining a power-law function with time-dependent queueing analysis. Additionally, the model incorporates the marginal cost of capacity, including the effects of economies of scale. This allows the calculation of the marginal cost price under a dynamic framework. The model accounts for nonlinear behaviour of port demand, which is sensitive to price and service levels. The effects over time of cost and service levels on the port’s operational performance are quantified. The proposed model allows determining the optimal timing for capacity investment. The model is a starting point for the application of marginal cost pricing to ports. However, for practical application of such pricing method it is necessary to apply a system’s approach, as productivity and costs must be assessed at the terminal’s component level. This should allow the derivation of a marginal cost function at the terminal’s component level.     

顶推船队安全过弯的引航模型研究

根据船队在弯曲航段的运动特征，分析了船队过弯曲航道的数学模型；结合实船试验对模型进行了论证，得出船队过弯曲航道的一般规律。     

基于雷达网的舰艇编队作战能力评估模型

舰艇编队雷达网的作战能力很大程度上影响了编队的作战效能.利用定性和定量分析相结合的方法分析了影响舰艇编队雷达网作战能力的因素,建立了基于雷达网作战能力的编队综合作战能力指数模型.仿真结果表明,所建立的指数模型能反映编队装备体系效能与编队雷达网之间的关系,通过仿真计算几种舰艇编队编成模式下的综合作战能力指数,选择最优的编成模式.该模型对于辅助指挥员进行科学预测,合理编成编队,选择较好的配置方案,具有较好的指导意义.     

A model for the biaxial dynamic bending of unbonded flexible pipes

An analytical model is given to investigate the behavior of unbonded flexible pipes under biaxial dynamic bending. The stick-slip conditions of each wire are studied in the framework of incremental analysis by an operator splitting of the time step into a stick-state prediction and a slip-state correction step. The tension gradient is calculated using the classical return-mapping algorithm and the obtained tension gradients are integrated numerically to find the axial tension by imposing appropriate boundary conditions. From the axial tension the bending moments with respect to the principal bending axes of the pipe are obtained. Poisson's effect, bending induced tension in the wire, shear deformations of the supporting plastic layer and the changes of the effective torsion and curvature increments of the wire after slip occurs are taken into account in the model. The results of bending moment–curvature relationship from this model are compared with the test data from simple bending and good correlations are found. The comparison of the biaxial bending moment results between this model and the available model also shows good agreement.     

基于改进A*GBNN算法的AUV路径规划研究

针对现有的离散生物启发神经网络(Glasius bioinspired neural networks, GBNN)算法在未知环境下,存在的路径规划时间长、易陷入局部最优等问题,提出一种结合A*与GBNN模型的改进算法。在GBNN活性值栅格网络中,算法将各栅格的活性值作为A*的代价函数进行运算并使用跳点搜索规则优化,实现未知环境下的实时路径规划。仿真实验结果表明,该算法有效改善了自主水下航行器在未知环境下的寻路效率,可以满足自主水下航行器实时路径规划需求。     

Model and algorithm for container ship stowage planning based on bin-packing problem

In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage planning problem increases due to its multi-ports nature. This problem is NP-hard problem. In order to reduce the computational complexity, the problem is decomposed into two sub-problems in this paper. First, container ship stowage problem （CSSP） is regarded as “packing problem”, ship-bays on the board of vessel are regarded as bins, the number of slots at each bay are taken as capacities of bins, and containers with different characteristics （homogeneous containers group） are treated as items packed. At this stage, there are two objective functions, one is to minimize the number of bays packed by containers and the other is to minimize the number of overstows. Secondly, containers assigned to each bays at first stage are allocate to special slot, the objective functions are to minimize the metacentric height, heel and overstows. The taboo search heuristics algorithm are used to solve the subproblem. The main focus of this paper is on the first subproblem. A case certifies the feasibility of the model and algorithm.     

打造世界级油运"旗舰"--中远发展VLCC船队纪略

2001年,九届全国人大四次会议首次正式提出实施国家石油战略.2003年,十届全国人大会议审议了"关于我国政府应加快石油战略储备加强国家石油安全的提案",与会代表一致认为,我国要在21世纪与世界石油大国形成"制人而不制于人"的战略格局,加快石油战略储备步伐,建立一支海上油运"国家队"已成当务之急.     

Sea-going labour and Greek owned fleet: a major aspect of fleet competitiveness

This analysis aims to examine the current picture of maritime manpower in the Greek registered and owned fleet, as it has been formed during the post-war years. This objective entails the analysis of the current supply and demand for seafarers, the estimation of any shortfalls and their confrontation. Moreover, this study further investigates the contributory factors of the present employment trends, which simultaneously constitute special problems of the sea manpower of the Greek owned fleet and attempt some recommendations. In the context of the above mentioned objective, this analysis emphasizes issues such as recruitment, marine education and wastage. Furthermore, special consideration is given to the significance of labour costs for the development of the Greek owned fleet, particularly to subjects such as the various ways of reducing manning costs and their repercussions on the employment of Greek seamen. Finally, this analysis examines the trends of the state shipping policy concerning labour issues and proceeds to some recommendations.     

中国油运船队的战略选择——访大连远洋运输公司副总经理李玉平

目前,中国已成为全球第二大石油消费国和第三大石油进口国。进口原油中,有50%来自中东,22%来自非洲,12%来自东南亚。而且中国从这三个地区进口石油,不仅路途遥远,而且全部依赖海运。那么,如何才能建立起一支担负国家使命的油运船队?"国油国运"与油轮船队的国际化之间究竟是一种什么关系?大连远洋运输公司副总经理李玉平在接受本刊专访时,对此作了详细的阐释。     

Sea-going labour and Greek owned fleet: a major aspect of fleet competitiveness

This analysis aims to examine the current picture of maritime manpower in the Greek registered and owned fleet, as it has been formed during the post-war years. This objective entails the analysis of the current supply and demand for seafarers, the estimation of any shortfalls and their confrontation. Moreover, this study further investigates the contributory factors of the present employment trends, which simultaneously constitute special problems of the sea manpower of the Greek owned fleet and attempt some recommendations. In the context of the above mentioned objective, this analysis emphasizes issues such as recruitment, marine education and wastage. Furthermore, special consideration is given to the significance of labour costs for the development of the Greek owned fleet, particularly to subjects such as the various ways of reducing manning costs and their repercussions on the employment of Greek seamen. Finally, this analysis examines the trends of the state shipping policy concerning labour issues and proceeds to some recommendations.