The effect of location,mobility and socio-demographic factors on task and time allocation of households

This paper investigates the role of location factors in task and time allocation at the household level. It is hypothesized that, if time constraints are less binding as a result of living in an urban area or owning more cars, spouses engage more often and longer in out-of-home activities and schedule their activities more independently. The hypotheses are tested with logistic and Cox regression models of activity participation and time allocation on a data set collected in the Amsterdam–Utrecht region in the Netherlands. Results suggest that the hypotheses are supported with respect to specific household activity scheduling decisions.     

Decomposing travel times measured by probe-based traffic monitoring systems to individual road segments

In probe-based traffic monitoring systems, traffic conditions can be inferred based on the position data of a set of periodically polled probe vehicles. In such systems, the two consecutive polled positions do not necessarily correspond to the end points of individual links. Obtaining estimates of travel time at the individual link level requires the total traversal time (which is equal to the polling interval duration) be decomposed. This paper presents an algorithm for solving the problem of decomposing the traversal time to times taken to traverse individual road segments on the route. The proposed algorithm assumes minimal information about the network, namely network topography (i.e. links and nodes) and the free flow speed of each link. Unlike existing deterministic methods, the proposed solution algorithm defines a likelihood function that is maximized to solve for the most likely travel time for each road segment on the traversed route. The proposed scheme is evaluated using simulated data and compared to a benchmark deterministic method. The evaluation results suggest that the proposed method outperforms the bench mark method and on average improves the accuracy of the estimated link travel times by up to 90%.     

半潜平台推力器失效模式下的动力定位能力分析

动力定位能力分析对于推力器选型和推力器的配置选型,以及对于一条新设计的动力定位船舶的定位能力的初步检验具有重要意义。动力定位能力分析能够得到船舶在各个艏向角抵抗环境力的能力。文章通过自主开发的程序研究了半潜平台在推力器失效模式下的定位能力,对该程序中的推力分配方法进行了详细的阐述,并对某半潜平台的动力定位能力分析验证了该程序的可行性。研究推力器失效时船舶的动力定位能力,不但可以验证船舶定位时的安全性,而且还可以为推力系统的设计提供适当的建议。     

舰载无人机对低空目标预警配置方法研究

低空突防的飞机和反舰导弹是威胁水面舰艇编队生存的主要目标,针对目前水面舰艇编队对低空目标预警存在的问题,对舰载无人机对低空目标预警的特点进行了分析,提出了舰载无人机对低空目标预警的配置要求,给出了舰载无人机对低空目标预警的配置方法。     

城市公交线路运力配置合理性研究

在城市公交运力调控必要性分析的基础上,对公交线路运力资源合理配置的含义进行界定,并提出其目标和实现原则,可得到公交线路运力合理配置的理论框架,对于相关研究具有参考价值。     

基于喷水推进器的单手柄操纵系统推力分配策略

目前国内基于喷水推进器的单手柄操纵系统应用较少,通过人工控制2套推进装置的6个参数来实现船体的平移运动操纵复杂、难度大,由此,对基于喷水推进器的单手柄操纵系统推力分配策略进行研究。推力分配是单手柄操纵系统的关键技术之一,其任务是将手柄输出的合力指令分配给各推进器。根据喷水推进器的特性,提出级联广义逆结合组合偏置的控制策略。该推力分配策略基于能量最优、艏向优先的方法,能自适应地调整偏置量,并兼顾喷水推进器的操纵性。仿真结果表明,该策略能适应喷水推进器优异的操纵性。     

一个在船舶推力分配中避免奇异结构的简单方法

处在奇异结构的船舶可能会突然失位,因为无法及时提供船舶所需的推力.文章提出了一个在船舶推力分配中避免奇异结构的简单方法.为了验证这个简单方法的效果,进行了一个半潜平台的时域模拟.时域模拟中用到了两种避免奇异结构的方法,包括新提出的方法和文献中经常提到的典型方法.从结果中可以得出,这个新方法具有和典型方法同样好的推力分配效果.用这个简单方法,虽然消耗的能量有少量增加,但时域模拟所花的时间大大地缩减了.这个简单方法的高效率可以保证它在船舶动力定位的实时推力分配中得到更广的应用.     

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研究了不确定环境下物流中心的选址优化问题,在随机优化模型的基础上,采用遗憾模型的形式构建了相关问题的鲁棒优化模型。分析了鲁棒优化模型与确定性优化模型、随机优化模型的关系,并在此基础上给出了求解鲁棒优化模型的两种方法——枚举法和遗传算法。以Visual Studio6.0为平台,以Visual C++为开发语言编写了两种算法的代码,代码中通过调用Lingo9.0来求解确定性优化模型和两阶段随机优化模型。利用上述两种算法对若干算例进行了测试,结果表明,本文给出的算法能够满足问题求解需要,与随机优化模型最优解相比,鲁棒优化模型的最优解对各情景下参数扰动的现象敏感程度更低,因此具有更低的风险。     

Energy-Efficient Deterministic Fault-Tolerant Scheduling for Embedded Real-Time Systems

By combining fault-tolerance with power management, this paper developed a new method for aperiodic task set for the problem of task scheduling and voltage allocation in embedded real-time systems. The schedulability of the system was analyzed through checkpointing and the energy saving was considered via dynamic voltage and frequency scaling. Simulation results showed that the proposed algorithm had better performance compared with the existing voltage allocation techniques. The proposed technique saves 51.5% energy over FT-Only and 19.9% over FT+EC on average. Therefore, the proposed method was more appropriate for aperiodic tasks in embedded real-time systems.     

公路客运站场体系投资分配方法

为合理划分公路客运站场体系中不同建设主体的投资份额,对公路客运站场体系的层级结构及其地方性准公共产品特征进行分析,并根据“受益原则”将公路客运站场的受益群体分为全国性、区域性与地区性客流三个层次,由此可建立基于受益群体构成的公路客运站场投资分配模型。实例表明,基于受益群体构成的公路客运站投资分配方法可行,规划方案可操作性强。