后行生产任务资源配套系统框架及其应用

根据目前船舶的生产特点,结合造船工艺流程,从资源与需求匹配上着手,通过数学模型的建立,开发后行生产任务资源配套系统。该系统具有成本低、适应公司生产、后续扩展方便等特点。通过此系统的应用,可实现资源的统一平衡、配送,提高数据处理的及时性、准确性,有利于公司日程管理,对实际生产具有指导意义。     

高速列车跟驰运行控制策略与安全车距的互动演化

为实现高速列车的安全、高效、平稳运行,利用Petri网描述与分析了给定跟驰状态下高速列车控制策略与安全车距的互动演化机理,探讨了高速列车复杂跟驰形势下的安全车距计算问题,建立了能够反映高速列车控制策略的停车减速运行数学模型,提出了基于控制策略的安全车距计算方法,以满足高速列车当前跟驰状态下行为调整的安全性、高效性和平稳（舒适）性和有助于动态安全车距和控制策略的实时标定。在前车速度分别为250、300、350 km·h-1,后车速度为300 km·h-1三种跟驰状态下,计算了前后车分别采取不同的控制策略时应保持的安全车距。计算结果表明：随着前后车控制策略的变化,安全车距是不同的,对列车行为调整的平稳（舒适）性与跟驰效率的影响也存在差异;综合考虑安全、效率和列车行为调整的平稳（舒适）性,宜针对高速列车不同跟驰状态重新标定不同跟驰控制策略下的安全车距,并建立相应的数据库,作为列车运行和控制的依据。     

不同运行方式下高速公路交通流特征对比

六车道及以上高速公路可实行混合行驶和分车型分车道行驶等不同的运行方式,为了掌握其效果并合理选用,需对比它们的交通流特征。选择年日均交通量（AAOT）较为接近但运行方式不同的两条六车道高速公路,统计分析在高峰期0.5 h 内的车型分布、交通量、速度和车头时距数据。结果表明,在分车型分车道行驶时,大量货车向车道3转移,使各车道的交通量更均匀,同时,车道1、2的平均速度提高,车头时距更加离散,而车道3的速度下降,车头时距更加紧密。这说明分车型分车道行驶实际上是对车道进行差异化管理,内、外侧车道分别以提高服务水平和通行能力为主要目标。但是,混行在同一车道上的不同车型,速度差异进一步增大,应严格禁止不按规定车道行驶的行为。     

Developing a Computer Program for Detailed Study of Planing Hull＇s Spray Based on Morabito＇s Approach

Recently, Morabito （2010） has studied the water spray phenomena in planing hulls and presented new analytical equations. However, these equations have not been used for detailed parametric studies of water spray around planing hulls. In this paper, a straight forward analysis is conducted to apply these analytical equations for finding the spray geometry profile by developing a computer program based on presented computational process. The obtained results of the developed computer program are compared against existing data in the literature and favorable accuracy is achieved. Parametric studies have been conducted for different physical parameters. Positions of spray apex are computed and three dimensional profiles of spray are examined. It is concluded that spray height increases by an increase in the speed coefficient or the deadrise angle. Ultimately, a computational process is added to Savitsky＇s method and variations of spray apex are computed for different velocities. It is shown that vertical, lateral, and longitudinal positions of spray increase as the craft speed increases. On the other hand, two new angles are defined in top view and it is concluded that they have direct relation with the trim angle. However, they show inverse relation with the deadrise angle.     

长江口航道规划整治参数及整治方案研究

综合采用案例和理论分析、河势分析以及潮流数学模型研究等手段,在确定航道整治水位、弯道形态和放宽率等参数的基础上,服务于现有航道规划目标和功能定位,研究确定了长江口阶段性航道整治方案和整治线,以指导规划期内的航道建设。研究成果对《长江口航道发展规划》的编制起到一定的支撑作用。     

不确定性航线配船数学模型建模方法

提出基于随机、模糊模拟的改进粒子群算法,避免了粒子群算法容易出现的早熟现象,加快了计算速度。实例计算表明该算法有效性。     

二维泥沙数学模型的改进——模型的建立

本文针对河道弯曲、狭长的特点,引进贴体坐标.将复杂的河道计算域转换成规则矩形域,使问题在规则域上求解.拟合坐标系下模型改进表现在以下两方面,一是引进紊动动能和紊动耗散率闭合雷诺方程,使模型能够回答整治工程局部水流结构,如回流现象,二是建立了一种新的悬沙输移模式,该泥沙模型能体现悬沙与床沙交换机理,既适用于水库上游淤积计算,也适用于水库下游冲刷计算.     

Modelling and optimisation of online container stacking with operational constraints

Container transportation plays a critical role in the global shipping network and container terminals need to improve their operations to increase efficiency. Storage yard of a container terminal is a temporary area where the containers stay until they are shipped to their next destination. We concentrate on increasing the efficiency of the storage yard by developing online stacking policies for each incoming container. An unproductive move of a container, performed to reach another container stored underneath, is called reshuffling. The objective in container stacking problem is to minimise the number of reshuffles, thereby increasing the efficiency of terminal operations. Additional weight-related operational constraints bring additional complexity to the online stacking decisions. We propose a mathematical model for the optimal online assignment of an incoming export, transit, import or empty container. We also propose an optimal online stacking policy and compare it with a random policy through simulation. Additionally, lower bounds for the performance measures are obtained through simulation by relaxing the operational constraints of the problem in a third stacking policy. We present and discuss the computational results in terms of four main performance measures.     

山区河流沙卵石浅滩整治线宽度确定

航道整治中整治线宽度的确定是整治成败的关键因素之一。在考虑山区河流挖槽稳定性以及船舶上滩能力基础上对整治线宽度计算公式进行改进,提出适合山区河流沙卵石浅滩整治线宽度的计算公式。并通过工程实例借助数学模型对计算的整治线宽度进行验证并提出优化。整治线宽度的确定是一个系统性工作,传统的整治线宽度计算公式与该公式的计算值仅可作为参考值。为达到良好的整治效果,需要通过数学模型以及河工物理模型试验对整治线宽度进一步修正。     

基于GIS城市体育场最佳选址问题的研究

选址问题种类繁多,实现的方法和技巧也是多种多样,造成这种多样性的原因主要在于对"最佳位置"的解释,即用什么标准来衡量一个位置的优劣.本文就体育场这一个特殊的设施为例,本着其能为民长远服务的原则,用城市居民到体育场的平均路径最短这一目标建立了体育场的最佳选址模型.与以往不同的是,本文在最短路径算法的基础上,考虑了道路的畅...