车辆数目未知的带时间窗口的车辆路径混合遗传算法

研究带时间窗口的车辆路径问题(VRPTW),主要考虑车辆容量约束、时间窗口约束、最大距离等约束,且完成配送所需的车辆数目不确定,要求在车辆数目最少的条件下再使总的行驶路径最短.用基于邻域搜索的混合遗传算法求解该问题,该算法既具有遗传算法的全局搜索能力,又具有邻域搜索算法的局部搜索能力.在求解过程中,设计新的前置交叉算子进行遗传操作,然后进行互换和逆转等邻域操作.应用MATLAB语言编程进行模拟计算,结果表明该混合遗传算法明显增强了群体演化的质量,提高了算法收敛速度,较好地解决了早熟收敛问题.     

混合超启发式法求解大规模VRP的优化研究

车辆路径是一类NP(non-deteministic polynomial)完全问题,研究解决车辆路径问题的高质量启发式算法有着重要理论价值和现实意义.提出一种将最近邻搜索法和禁忌搜索法优势相结合的混合超启发式算法,用来解决带容量约束的车辆路径问题.先利用最近邻搜索法构建初步路线,再利用禁忌搜索法对内部线路和互跨线路进...     

如何有效发挥渔船在海上搜救中的积极作用

介绍了浙江洞头辖区海上搜救现状和存在的困难,分析了制约渔船积极参与海上搜救的主要因素,对如何有效发挥渔船在海上搜救中的积极作用提出了几点建议。     

直升机吊放声纳螺旋线形搜潜概率分析

利用概率论的方法建立了直升机吊放声纳螺旋线形搜潜概率模型,并采用蒙特卡洛仿真方法进行验证;利用概率模型由解析的方法求得最优的相邻吊放点间隔,并且拟合得到吊声的战术作用距离与最优相邻吊放点间隔系数的关系式,为反潜直升机使用吊放声纳进行螺旋线形搜潜的战术应用提供参考。     

舰船摇摆下探雷声纳工作参数优化设置研究

针对舰船摇摆下,探雷声纳工作参数难以确定的特点,建立了舰船摇摆模型和探雷声纳多波束照射海底模型,定义了探雷声纳有效搜索面积,给出了舰船摇摆下探雷声纳工作参数的最优化设置建议,该方法简便有效,为探雷声纳的作战使用提供了依据。     

Investigating UAVs applications and intention to use in the maritime shipping in Taiwan

ABSTRACT

This study empirically evaluated the effects of unmanned aerial vehicles (UAVs) applications and acceptable cost on intention to use UAVs in maritime shipping contexts. Factor analysis was employed to identify key UAVs applications (i.e. pollution forensics, supervision and service, search and rescue, humanitarian and emergency delivery, and safety and security), acceptable UAV cost, and intention to use UAVs. Survey data were collected from 201 respondents working for a maritime port corporation, shipping company, agency, and stevedoring company, and then hierarchical regression analysis was conducted to test research hypotheses and examine the effects of UAVs applications and acceptable cost dimensions on intention to use UAVs. The results suggested that the pollution forensics, supervision and service, search and rescue, humanitarian and emergency delivery, and safety and security dimensions positively affected intention to use UAVs. The study findings also revealed negative associations among seniority, turnover, and intention to use UAVs. Theoretical contributions and managerial implications are proposed to assist maritime port bureaus, corporations, and operating practice design in remaining competitive and efficient.     

论海上搜救任务协调员（SMC）资格与职责

海上搜救任务协调员是海上搜救的组织者、策划者、指挥者、总结评估人,主导着收集、评估信息,制定行动方案,组织搜救力量实施救助．责任重大。因此,有必要对其资格与职责进行探讨。     

Taxi services with search frictions and congestion externalities

Built upon the previous studies, this paper incorporates both bilateral taxi–customer search frictions and congestion externalities into the economic analyses of the equilibrium properties of taxi markets. We take account of congestion externalities by adopting a realistic distance‐based and delay‐based taxi fare structure. We first investigate comparative static effects of regulatory variables of taxi fare and fleet size on the market and then examine the properties of the Pareto‐efficient solutions for simultaneous maximization of social welfare and taxi profit in the congested market. Copyright © 2012 John Wiley & Sons, Ltd.     

多模式公共交通网络行程时间可靠性评价

随着城市经济的快速发展,以快速轨道交通与常规公共汽车交通为主体的多模式公交网络逐步成型,城市居民在多方式换乘条件下的行程时间可靠度越来越成为评价多模式公交网络服务水平的重要指标。以典型城市的多模式公交网络为研究对象,结合图论及状态增广方法描述,设计换乘次数约束下的任意OD对多路径搜索算法,建立行程时间可靠性评价模型,从而为评价和改善多模式公交网络服务水平提供有效的决策支持。     

应用改进和声搜索算法分析边坡的稳定性

为提高基本和声搜索算法的全局搜索能力,提出了基于未知解空间探索与已知解空间开发相平衡的改进和声搜索算法。在基本和声搜索算法迭代一段时间后,在当前最好解的周围进行开发,所得的改进解反馈给基本和声搜索算法,继续进行迭代,如此反复,直至没有更好解产生为止。将新算法用于求解边坡最小安全系数,算例分析表明其效率比基本和声算法有较大提高。