全船有限元简化方法在总纵强度计算中的应用

采用全船有限元总强度计算的简化方法,阐述了具有长上层建筑、大开口、全通甲板的船舶在垂向弯矩作用下的总强度应力分布情况,提出了非常规结构船舶总强度计算方法,分析了上层建筑参与总强度的有效度。对有效避免波浪载荷及平衡力计算带来的总强度计算误差和庞大的计算工作量,缩短计算周期以及优化结构等提供指导。     

深水八角形FDPSO总体性能分析

从技术与经济性角度对比分析现有的FDPSO船型,最终选定八角形FPDSO为目标船型。根据FDPSO功能要求制定技术指标,进行总体设计、总体尺度规划和垂荡板尺寸优化,以及系泊系统设计,完成八角形FDPSO的概念设计,计算分析其运动性能、稳性和系泊系统能力,结果表明八角形FDPSO总体性能满足要求,系泊系统设计合理。     

Investor herding behaviour in globally listed shipping stocks

ABSTRACT

This study undertakes one of the first empirical attempts to investigate and contribute a set of innovative findings to investor herding behavior and herding spillover effects in globally listed shipping company stock returns. Distinguishing between OECD and Non-OECD markets, herding behavior is tested on a diversified set of shipping companies traded in international equity markets, over different business cycle phases, financial crises, and external shocks. A set of dynamic models, well established in the relevant behavioral finance literature, is implemented. Empirical evidence indicates investor herding behavior in shipping stock returns and herding spillover effects between different shipping sectors, albeit not robust in all cases. These challenging findings can have a material impact on efficient investment and financing decisions of shipping market players.     

Optimal toll locations and toll levels in congestion pricing schemes: a case study of Stockholm

As congestion pricing has moved from theoretical ideas in the literature to real-world implementation, the need for decision support when designing pricing schemes has become evident. This paper deals with the problem of finding optimal toll levels and locations in a road traffic network and presents a case study of Stockholm. The optimisation problem of finding optimal toll levels, given a predetermined cordon, and the problem of finding both optimal toll locations and levels are presented, and previously developed heuristics are used for solving these problems. For the Stockholm case study, the possible welfare gains of optimising toll levels in the current cordon and optimising both toll locations and their corresponding toll levels are evaluated. It is shown that by tuning the toll levels in the current congestion pricing cordon used in Stockholm, the welfare gain can be increased significantly, and furthermore improved by allowing a toll on a major bypass highway. It is also shown that, by optimising both toll locations and levels, a congestion pricing scheme with welfare gain close to what can be achieved by marginal social cost pricing can be designed with tolls being located on only a quarter of the tollable links.     

一类新的修正PRP共轭梯度法

提出一类带有新参数公式的的修正PRP共轭梯度法.该方法能自动保证参数公式的非负性.在适当条件下,证明了算法在广义Wolfe-Powell线搜索和Wolfe-Powell线搜索下全局收敛,初步的数值试验结果表明新方法有较好的应用前景.     

IIR数字滤波器设计的搜寻者优化算法

为进一步提高无限冲击响应(IIR)数字滤波器的性能,提出了一种基于搜寻者优化算法(SOA)的IIR数字滤波器设计方法.SOA基于模拟人的随机搜索行为,由利用位置变化评价得到的经验梯度确定搜索方向,由采用简单模糊规则的不确定性推理确定搜索步长,通过搜寻者在搜索空间的位置更新,实现对优化问题的求解.2个典型设计实例的仿真结果表明,与差分进化算法(DE)和3种改进的粒子群算法(PSO)相比,SOA具有较好的全局寻优能力和较快的收敛速度,能有效地应用于IIR数字滤波器的没计.     

具有周期投放、捕获及非线性扩散的最优化模型

考虑有资源保护区且保护区内外存在非线性扩散作用的资源种群开发模型,获得了周期扩散模型正周期解的存在性与全局渐近稳定性条件．以周期投放、周期捕获为控制策略,持续产量最大化、持续经济租金最大化为管理目标,利用Pontryagin最大值原理得出此周期投放、捕获最优化问题的最优投放hopt（t）、捕获策略Eopt（t）及相应资源种群的最优规模为xopt1（t）,xopt2（t）,并举例说明．     

基于解析解的GPS伪距量测定位趋近算法

用几何方法,给出了二维、三维测距定位问题解的解析表达式,在此解析解的基础上对GPS测码伪距定位问题提出一种趋近计算方法,并讨论了其收敛性,给出了其收敛的一个充分条件和解析求解中多解的裁决方法.     

MPI网络在船舶电站控制系统中的应用

S7-300CPU集成了MPI通信协议,可以通过MPI网络来实现全局数据通信,在PLC之间进行少量数据交换。通过在某船舶电站控制系统中的应用表明,采用MPI网络通信方式简单、有效而实用。     

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交通运输业能耗强度、碳排放强度的上升趋势,与其他行业稳步下降的趋势相悖,使得交通运输业逐步成为节能环保的短板之一.本文在考虑CO2排放约束的前提下,构建超效率非期望Min DS模型,评价1995—2013年中国30省份交通运输业能源效率,并利用Global Malmquist-Luenberger指数,动态分析效率的变化情况.研究表明,各地区交通运输业能源效率总体呈反N型波动下降;东部、西部地区各省表现出较大差异性;中部、东北地区内各省表现出一致性,但整体水平较低;超效率非期望Min DS模型有效克服了非期望SBM模型无法完全排序和低估效率结果的问题;造成交通运输业能源效率下降的主要因素是技术效率的下降,但这一状况将在未来得到改善.