Ship-berth link performance evaluation: simulation and analytical approaches

In this paper we consider the performance evaluation of ship-berth link in port. The efficiency of operations and processes on the ship-berth link has been analysed through the basic operating parameters such as berth utilization, average number of ships in waiting line, average time that a ship spends in waiting line, average service time of a ship, average total time that a ship spends in port, average quay crane (QC) productivity and average number of QCs per ship. All the main performances of the ship-berth link are given. This is one of the problems faced by planners and terminal operators in ports. In this paper, we propose two models based on simulation and queuing theory, respectively, in order to determine the performance evaluation of ship-berth link in port. Numerical results and computational experiments are reported to evaluate the efficiency of the models for Pusan East Container Terminal (PECT).     

战术数据链抗干扰性能仿真技术

战术数据链抗干扰性能仿真可定量描述出干扰的影响,具有重要的研究意义。本文介绍了战术数据链及其仿真技术的发展现状,重点分析了Link 16终端设备联合战术信息分发系统(JTIDS)抗干扰的关键技术:信道编码技术、扩频技术与调制技术。在此基础上,采用Matlab提供的仿真平台Simulink建立了战术数据链的链路级仿真模型,实现了其抗干扰性能的仿真。相关研究成果可应用于射频干扰对数据链性能影响的定量评估,以及数据链抗干扰或者干扰策略优化设计中。     

Planning framework of analytical approaches applied to Zairean transportation

The purpose of the article is to provide an analytical planning framework which includes decision makers, organizations imposing operational and institutional constraints, direct customers and indirect beneficiaries. All these actors have differ-ent, only partially overlapping, interests; this increases the complexity of capital budgeting and imposes limitations on decision-making framework has important implica-tions for project selection, charging and depreciation policies. Although the illus-trations are limited to transport planning, the framework can be easily applied to any sector or country. For example, the English engineering students applied the framework to 18 industries in the U.K.: Auto-diesels, Bass, British Airways, British Gas, British Oxygen, British Petroleum, British Rail, British Steel, British Telecom, East Midland Electricity, Guinness, Imperial Chemical Industries (ICI), Inter-national Computers Limited (ICL), Marks & Spencer, Mercury Communications, National Westminster Bank, Rover and Thames Television (see A. Kelvin, 1993, Increasing student participation in the learning process. Higher Education, 26(4), December, 449-470).     

水下航行器水下障碍规避性能分析与仿真

水下航行器的障碍躲避是提高水下航行器生存能力的关键技术,针对信息融合跟踪算法避障容易误差偏差和局部收敛的问题,提出一种基于Kalman滤波量化融合规避的水下航行器水下避障算法。构建水下航行器的运动系统方程,采用方位信息的量化融合方法进行自适应路径规划,结合Kalman滤波进行障碍信息的干扰抑制,采用强跟踪滤波实现障碍参量信息量化融合规避,实现水下航行器水下障碍躲避。仿真结果表明,采用该方法进行水下航行器避障,能有效规避障碍目标,提高对障碍物的方位估计精度,有效规避的准确概率达到最优。     

螺旋桨敞水性能数值预报方法研究

针对E779A型螺旋桨和30.8万吨超级油轮(VLCC)螺旋桨进行敞水性能数值计算方法研究,考察了网格、计算域、压力离散格式等对数值计算的影响,并对收敛过程、结果进行了讨论、分析,使螺旋桨敞水性能计算流程进一步成熟,为进一步的螺旋桨水动力性能数值计算提供准备。     

虚拟仿真技术在溢油回收装置结构性能评估和轻量化设计中的应用

针对传统设计方法依靠经验开展设计的缺陷,提出了基于虚拟仿真技术的结构性能评估和优化设计方法.针对某溢油回收船溢油回收装置,利用虚拟仿真技术对其结构性能进行评估,并利用拓扑优化技术开展溢油回收装置结构的轻量化设计,实现以仿真来驱动设计,以期为虚拟仿真技术在船舶设计特别是溢油回收船溢油回收装置设计中的应用提供参考.     

虚拟仿真技术在溢油回收装置结构性能评估和轻量化设计中的应用

针对传统设计方法依靠经验开展设计的缺陷,提出了基于虚拟仿真技术的结构性能评估和优化设计方法。针对某溢油回收船溢油回收装置,利用虚拟仿真技术对其结构性能进行评估,并利用拓扑优化技术开展溢油回收装置结构的轻量化设计,实现以仿真来驱动设计,以期为虚拟仿真技术在船舶设计特别是溢油回收船溢油回收装置设计中的应用提供参考。     

LiCl溶液除湿器的数值模拟和性能分析

文中对LiCl溶液除湿器的传热传质过程进行热力学分析,根据除湿器结构、溶液与空气的流动方式建立了该除湿器的热质交换物理模型和数学模型,并进行了推导和求解;通过MATLAB仿真模拟,计算空气和溶液进口参数的变化对相关指标的影响,得到除湿器各入口参数对评价指标的影响曲线.模拟分析表明:除湿溶液进口质量浓度、温度、质量流量和空气进口质量流量对除湿器性能具有较大影响;同时也验证了湿阻与溶液除湿系统除湿性能之间的关系,为进一步研究提供参考.     

舰船任务成功模拟仿真评估技术

文章首先简单介绍了任务成功预测性评估模型和追溯性评估模型;其次运用模拟仿真评估技术,通过3个仿真机,对舰船一段时间内的使用——故障——修理——保障进行仿真,得到与真实情况相近的维修数据系统的数据记录,然后评估这个仿真期间舰船的任务成功和保障系统的保障能力。利用仿真系统不仅可以实现大型复杂离散系统的指标评价,通过调试还可以筛选出最优保障、修理和使用策略,并且可以对执行具体的复杂任务进行预测,具有一定的实际指导意义。     

Optimum throughput and performance evaluation of marine terminals

The performance of marine terminals has generally been evaluated by comparing their actual throughputs with their optimum throughputs. The engineering approach that generally has been used to determine optimum throughputs may be appropriate when terminals have natural hinterlands. In a deregulated (competitive) environment in which the natural hinterlands of marine terminals have become diffused, the economic approach for determining optimum throughputs should be condiered. In such an environment, marine terminals are not only concerned with whether they can handle a given amount of cargo but also whether they can compete for such cargo.     

螺旋桨水动力性能及流固耦合数值模拟

根据螺旋桨局部坐标转换成全局坐标的型值,建立螺旋桨的三维几何模型。基于商业软件,分别研究分区混合流体网格和结构网格的划分。使用Fluent软件分析螺旋桨的敞水性能,结合MRF转动模型和SST湍流模型研究螺旋桨在不同进速系数下的推力、转矩和敞水效率。与实验测量值比较,证实了该方法的工程可用性。基于Workbench平台,将CFD软件计算和有限元求解耦合起来,研究螺旋桨敞水时的单向流固耦合作用,对桨叶的结构强度进行校核计算,并分析螺旋桨应力,变形与进速系数的关系。     

数值拖曳水池与潜艇快速性CFD模拟研究

详细介绍了中国船舶科学研究中心所建立的数值拖曳水池中的潜艇快速性CFD模拟研究.明确了潜艇阻力、流场、自航(艇/桨干扰)水动力以及螺旋桨敞水水动力的计算方法.同时对潜艇快速性算例进行了系统分析,详细给出了数值预报精度.这些算例的计算模型包含15条系列回转体模型、10条系列全附体潜艇模型、SUBOFF潜艇模型、多条供计算验证所用的潜艇模型和螺旋桨模型.文中的研究结果是数值水池的重要组成部分,可资今后潜艇绕流数值计算借鉴与采用.     

Evaluating seaport policy alternatives: a simulation study of terminal leasing policy and system performance

The competitive characteristics of the North American seaport industry have, in theory, been causally linked to excess investment and low terminal throughput productivity. This paper empirically examines the link between seaport authority container terminal leasing policy and throughput productivity. Recent advances in inventory theory applied to service industries suggest the pooling of demand uncertainty can yield lower costs without sacrificing customer service. This concept is applied to a container seaport using simulation. The effort compares key output measures from a realistic base case model of the seaport to those generated by an alternative terminal leasing policy. It is shown that the pooling of demand in a common-user seaport reduces total vessel time in port by 17.1% with no reduction in TEU throughput. Throughput productivity is improved for the highest capacity terminals, while lower capacity terminals are made available for additional users or alternative uses.     

Evaluating seaport policy alternatives: a simulation study of terminal leasing policy and system performance

The competitive characteristics of the North American seaport industry have, in theory, been causally linked to excess investment and low terminal throughput productivity. This paper empirically examines the link between seaport authority container terminal leasing policy and throughput productivity. Recent advances in inventory theory applied to service industries suggest the pooling of demand uncertainty can yield lower costs without sacrificing customer service. This concept is applied to a container seaport using simulation. The effort compares key output measures from a realistic base case model of the seaport to those generated by an alternative terminal leasing policy. It is shown that the pooling of demand in a common-user seaport reduces total vessel time in port by 17.1% with no reduction in TEU throughput. Throughput productivity is improved for the highest capacity terminals, while lower capacity terminals are made available for additional users or alternative uses.     

基于层次分析法的动力系统技术状态评估方法

为了对船舶动力系统设计研究、维修保障工作提供指导和借鉴作用,文章分析船用动力系统技术状态的特点及其评估方法研究的必要性,讨论动力系统技术状态评估参数及指标。结合动力系统主要设备特点,运用层次分析法建立动力系统技术状态评估模型,并定性、定量的对评估中各指标权重进行分析,最终的分析结果与船舶实际情况相符,从而验证层次分析法对动力系统技术状态评估的科学性和价值。     

基于层次分析法的动力系统技术状态评估方法

为了对船舶动力系统设计研究、维修保障工作提供指导和借鉴作用,文章分析船用动力系统技术状态的特点及其评估方法研究的必要性,讨论动力系统技术状态评估参数及指标.结合动力系统主要设备特点,运用层次分析法建立动力系统技术状态评估模型,并定性、定量的对评估中各指标权重进行分析,最终的分析结果与船舶实际情况相符,从而验证层次分析法对动力系统技术状态评估的科学性和价值.     

The link between economic and environmental performance of the top 10 U.S. ports

Ports currently face increasing demands to address a variety of environmental issues and achieve sustainability objectives. Using insights from the resource-based view of firms, this study examines the link between economic performance (EP) and environmental performance (ENP) of the top 10 U.S. seaports. Geospatial modeling is used to capture pollution incidents that can be geographically dispersed; in addition, both a bootstrap data envelopment analysis (DEA) approach and an undesirable DEA model are used to measure port ENP and EP. Our findings are in general consistent with assertions that positive EP can be attained in conjunction with good environmental practices. Ports’ capabilities of strategic capital investment in physical assets, collaborative interorganizational processes, and performance monitoring are essential, while they pursue both economic and environmental goals simultaneously.     

Control system design and performance evaluation of anti-pitching fins

We have investigated the usefulness of active stabilizing fins to reduce ship pitching under varying forward speeds, and in varying wave lengths. A 4-m self-propelled model ship and an electrohydraulically driven stabilizing fin system were used in our experiment. Pitch angles, pitch rates, and ship forward speeds were measured and fed back to a controller to calculate the deflection angle of the stabilizing fin. The effects of fin nonlinearity on achievable pitch reduction performance are discussed. It is shown that the desired pitch response can only be achieved when the fin is operated in the linear region. The overall dynamic response of the ship approaches open-loop behavior when the degree of nonlinearity is high. This simple analysis of the pitch stablizing system provides basic information to ship designers. Experimental results validate these design guidelines. Received for publication on Feb. 12, 1998; accepted on Dec. 8, 1999     

喷水推进泵空化性能数值模拟与试验验证

为研究喷水推进泵空化性能,采用计算流体力学(CFD)方法对自行设计的喷水推进泵内部空化流场进行了数值计算与分析。用六面体结构化网格对喷水推进泵的进流管道、叶轮、导叶体和出流管道进行网格划分;通过求解由SST湍流模型封闭的RANS方程计算得到喷水推进泵内部流场,计算得到的扬程、功率和效率特性曲线与试验结果吻合较好。文中还对多个流量的空化性能进行了数值预报,计算结果与试验数据在趋势上具有一致性;小流量工况的临界净正吸头与试验值误差较小,而大流量工况的临界净正吸头与试验值误差较大。研究结果表明:采用CFD方法预报喷水推进泵内部空化流场和空化性能是可行的,可作为喷水推进泵优化设计的有效途径。     

柔性腕的力学性能仿真分析

RCC是针对轴孔装配作业中插轴人孔作业和类似的插拔作业而设计的一种适从装置。主要对非线性有限元方法在RCC柔性腕的力学性能仿真中的应用进行了探讨和研究，进而为新型高性能柔性腕的设计提供理论依据和基础。