一种单轴旋转的车载IMU/DTU组合导航方法

长时间机动工况时,某些复杂路况和车况环境下,捷联惯导组合导航系统方位角误差将增大.基于已有组合导航算法框架,提出了一种基于单轴旋转调制的组合导航方法.采用21维IMU/DTU(里程计)误差状态构造状态方程,以捷联惯导解算的位移增量与里程计解算的位移增量之差作为观测量,Kalman滤波器融合惯导与里程计信息,利用旋转调制...     

Fulfillment by Amazon versus fulfillment by seller: An interpretable risk-adjusted fulfillment model

With dual-channel choices, E-retailers fulfill their demands by either the inventory stored in third-party distribution centers, or by in-house inventory. In this article, using data from a wedding gown E-retailer in China, we analyze the differences between two fulfillment choices—fulfillment by Amazon (FBA) and fulfillment by seller (FBS). In particular, we want to understand the impact of FBA that will bring to sales and profit, compared to FBS, and how the impact is related to product features such as sizes and colors. We develop a risk-adjusted fulfillment model to address this problem, where the E-retailer's risk attitude to FBA is incorporated. We denote the profit gaps between FBA and FBS as the rewards for this E-retailer fulfilling products using FBA, our goal is to maximize the E-retailer's total rewards using predictive analytics. We adopt the generalized linear model to predict the expected rewards, while controlling for the variability of the reward distribution. We apply our model on a set of real data, and develop an explicit decision rule that can be easily implemented in practice. The numerical experiments show that our interpretable decision rule can improve the E-retailer's total rewards by more than 35%.     

Schedule design for liner services under vessel speed reduction incentive programs

Gas and particulate emissions from ship transportation have been increasing in recent years. In order to mitigate ship emissions near coastal areas, voluntary vessel speed reduction incentive programs (VSRIPs) were put in place by a number of ports. This paper studies a schedule design problem faced by liner shipping companies under VSRIPs. It proposes a mixed-integer nonlinear mathematical model for the minimization of the total cost, consisting of fuel cost, as well as operating cost, minus dockage refunds. The model balances three determinants, that is, the compliance of VSRIPs, the speed limit (the maximum physical speed of ships and the upper speed limit imposed by VSRIPs), and the limited number of ships. An enumerative algorithm and a piecewise-linear approximation algorithm are developed, based on some properties of the nonlinear model. The efficiency of the proposed algorithms is validated through extensive computational experiments.     

火炮射击冲击加速度信号提取方法研究

火炮结构在受到射击产生的冲击时易发生故障,最终影响火炮的寿命和性能。故障信号通常淹没在冲击加速度信号中,不易被识别。针对上述问题提出一种基于经验小波变换(EWT)和能量算子的信号提取方法,通过能量算子增强冲击响应特征,改进传统EWT的频谱分割方法,将火炮加速度信号分解为多个模态,有效地提取火炮的冲击特征。实验表明,改进后的EWT方法相对传统EWT对故障信号提取效果更好,时频图表现更清晰。     

互联网环境下隐私安全风险评估体系构建

针对当前互联网环境下隐私风险来源复杂、隐私界定模糊、隐私保护不均所造成的隐私安全风险评估困难问题,借助信息安全风险评估模型,提取隐私风险来源、隐私类别、隐私保护实施三方面风险评估要素,通过结合隐私应用场景、综合多种评估方法、模拟隐私保护实施来生成综合评估模型,最终构建包括前置层、评估层和管理层的隐私安全风险评估体系。体系的构建有利于科学、准确地评估当网络环境隐私安全风险情况,指导隐私保护多层次、有重点地实施。     

Impacts of sequential acquisition,market competition mode,and confidentiality on information flow

We investigate information flow in a setting in which 2 retailers order from a supplier and sell to a market with uncertain demand. Each retailer has access to a signal. The retailers can disclose signals to each other (horizontal information sharing), while the supplier can solicit signals by offering retailers differential payments as incentives for signal disclosure (vertical information acquisition). In the base setting, market competition is in quantity, and a retailer can fully infer the signal that the other retailer discloses to the supplier. We show that the supplier prefers to sequentialize the procedure for information acquisition. Moreover, vertical information acquisition by the supplier is a strategic complement to horizontal information sharing between the retailers to establish information flow. In the equilibrium, the retailers have no incentive to exchange signals, but system wide information transparency can be realized through a combination of information acquisition and inference. We further study the signaling effect, whereby the supplier utilizes wholesale pricing as an instrument to affect the retailers' inference of the shared signals, and price competition to explore their impacts on the supplier's preference for sequential acquisition and the sustainability of information flow.     

电磁发射的出口速度及负载质量变化对导轨热量的影响

为分析不同发射出口速度、不同发射负载质量对导轨积累热量的影响,建立了导轨温度场模型,计算了导轨各点温度变化过程,并和光纤光栅温度传感器测量结果对比,验证了模型及测量结果的正确性。在此基础上,设计并进行了三种类型实验,分析了在不同发射速度、不同发射负载质量以及相同发射能级不同发射速度下的导轨热量积累差异。该结论为确定连发间隔、导轨冷却设计提供了有效参考。     

基于灰色聚类的管道电伴热系统安全评价

虽然管道电伴热系统在国防工业领域有着十分广泛的应用,但在实际使用过程中也经常会出现各种问题.本文针对管道电伴热系统安全性的评价问题,在分析总结管道电伴热系统常见故障的基础上,从系统设计、安装施工、电气连接与操作使用4个方面,选取17个影响因素构建管道电伴热系统安全评价指标体系,通过改进层次分析法计算得到各方案层的权重值...