船舶管线隔振支座布局优化设计的规范法

国内关于船舶管道隔振支承布局优化设计的标准和方法目前还没有建立,有关优化模型及算法的研究有待开展。借鉴美国ASME B31规范和综合考虑强度、刚度、稳定性、固有频率及振级落差等约束条件,提出了管线系统支座布局优化设计模型及规范设计法。该方法根据ASME B31规范初步确定支座的数量,通过几何优化设计支座的间距。提出迭代优化算法求解这上述问题,获得较优的支座数目与支座间距。通过算例,研究了不同优化目标函数的选择,(如支座造价、管线最大下垂或结构应变能等),对优化结果的影响;证明了有关模型与算法的有效性和实用性。     

半潜式平台动力定位推力系统分配策略研究

为使动力定位推力分配系统在任何时刻均能产生定位所需的力和力矩,保证船舶处于预定位置或航向,在考虑推进器回转速度、额定功率、工作区限制和避免分配矩阵奇异值等约束条件下,采用基于序列的二次规划法在每个控制指令间隔内求解凸二次规划问题,实现了推力在不同推进器之间的最优分配,使系统的总功率消耗达到最小并有效的减少了推进器的损耗,计算实例结果验证了该方法的有效性。     

完善行政复议举证责任分配制度的法律思考

文中借鉴诉讼举证责任的分配原理,结合行政复议实践,从法理基础、关联因素、制度选择等方面对行政复议举证责任分配制度的建立进行了深入分析并提出了一些建议,可供立法部门建立和完善行政复议举证责任分配制度时参考。     

Global force potential of over-actuated vehicles

This paper formulates force constraints of over-actuated road vehicles. In particular, focus is put on different vehicle configurations provided with electrical drivelines. It is demonstrated that a number of vehicles possesses non-convex tyre and actuator constraints, which have an impact on the way in which the actuators are to be used. By mapping the actuator forces to a space on a global level, the potential of the vehicle motion is investigated for the vehicles studied. It is concluded that vehicles with individual drive, compared with individual brakes only, have a great potential to yaw motion even under strong lateral acceleration.     

共享停车泊位的分配-定价-收益分配机制

为科学管理共享停车资源,构建一种共享停车泊位的分配-定价-收益分配机制。首先,以存在多个地块的区域为对象,根据出行者对不同地块及停车时间模式的选择偏好构建停车许可证的最优分配-定价模型,其中,最优分配模型为组合拍卖竞胜标确定问题(NP困难问题)。其次,利用Benders分解原理、对偶理论及新型升价拍卖代理系统构建调优法对停车许可证进行拍卖。最后,为调动共享泊位提供者的积极性,利用沙普利值法构建基于对社会福利贡献程度的停车收益分配模型。由理论分析及数值试验可知,运用上述机制可精确实现社会福利最优状态,最小竞争均衡价格与公平的收益分配。结果表明:①相较VCG机制与Leonard机制,调优法不仅可精确求解停车许可证的最优分配-定价,而且在算法最坏时间复杂度方面拥有更高效率;②在调优法的每个步骤中,即使停车许可证的分配并非最优,通过机制所实现的收费定价依然具有防止策略性操作的重要性质;③调优法可在较少的步骤之内实现较高的社会福利;④新型升价拍卖代理系统拥有多项式型的最坏时间复杂度;⑤通过最优分配-定价机制可获得每位出行者的选择偏好,进而可计算不同泊位提供者组合条件下的社会福利,实现沙普利值法在现实应用中的可计算性。     

An application of centralized data envelopment analysis in resource allocation in container terminal operations

This paper presents an application of centralized data envelopment analysis (CDEA) to analyse the performance of a number of container terminals supervised by one liner shipping company. It provides a systematic and centralized perspective of resource reallocation based on one company’s perspective. The numerical results show that two of the five dedicated terminals are, by and large, efficient, but the other three need resources to be reallocated. Under the minor adjustment scenario, the liner shipping company should reduce the aggregated amount of the labour cost and the hauling equipment should be transferred to different terminals in America. Under the major adjustment scenario, both the labour and hauling equipment could be reduced.     

基于大偏差有效带宽的多业务带宽动态分割策略

提出了一种近似"无级"的带宽动态分割策略.它根据现有基于有效带宽的CAC策略得到的最大用户数和系统容量满足的关系式,在业务带宽最小配额与当前用户数相匹配的前提下,用搜索的方式获得使所有业务的有效带宽和最大时的各带宽配额.该策略可满足分组交换网络能对业务分配任意大小带宽的需求.     

Integration of vehicle yaw stabilisation and rollover prevention through nonlinear hierarchical control allocation

This work presents an approach to rollover prevention that takes advantage of the modular structure and optimisation properties of the control allocation paradigm. It eliminates the need for a stabilising roll controller by introducing rollover prevention as a constraint on the control allocation problem. The major advantage of this approach is the control authority margin that remains with a high-level controller even during interventions for rollover prevention. In this work, the high-level control is assigned to a yaw stabilising controller. It could be replaced by any other controller. The constraint for rollover prevention could be replaced by or extended to different control objectives. This work uses differential braking for actuation. The use of additional or different actuators is possible. The developed control algorithm is computationally efficient and suitable for low-cost automotive electronic control units. The predictive design of the rollover prevention constraint does not require any sensor equipment in addition to the yaw controller. The method is validated using an industrial multi-body vehicle simulation environment.     

Analysis of within-household effects and between-household differences in maintenance activity allocation

This paper investigates the allocation of household individuals to out-of-home maintenance activities using the rich activity-travel diary data from the San Francisco Bay Area. Two inter-related decisions are considered in this context: (i) whether the given activity episode is performed individually (solo) or jointly, and (ii) the person who participates in the activity, if it is a solo activity. To account for the conditional nature of the solo activity person selection, a nested mixed logit modeling framework is proposed and implemented to jointly analyze person allocation for all maintenance activities performed by a household on a given day. The model is used to investigate within-household effects and between-household differences. The proposed model relaxes some important restrictions in person allocation models by accounting for various sources of correlations and relaxing the assumption of constant variance across households. The proposed model is used to analyze the differences in person allocation between different types of households. The results indicate that life-cycle and household role, income, gender, employment status, and several types of constraints (activities including cost, time-availability, vehicle-availability, coordination constraints, and child-care obligations) affect person allocation decisions in the context of maintenance activities. The empirical results indicate the presence of various sources of correlations across persons, over activities, and within-household that are significant. In addition, the data also provides evidence that the unobserved variances in person selection utilities are not constant across households. A better understanding of these within-household interactions and between-household differences may be used in activity-based simulation models and to develop more effective and focused demand management measures.