新型钢-混凝土组合板的力学性能研究

以加劲肋形式、组合板厚度和栓钉布置为参数,进行了9块新型组合板的力学性能试验.试验结果表明,组合板的正截面承载力可按基于修正平截面假定的极限状态计算;组合板的跨中挠度,可在按现行规范计算的基础上,加上考虑界面滑移影响的附加变形值予以修正.     

Capacity allocation with traditional and Internet channels

In this paper we study a capacity allocation problem for two firms, each of which has a local store and an online store. Customers may shift among the stores upon encountering a stockout. One question facing each firm is how to allocate its finite capacity (i.e., inventory) between its local and online stores. One firm's allocation affects the decision of the rival, thereby creating a strategic interaction. We consider two scenarios of a single‐product single‐period model and derive corresponding existence and stability conditions for a Nash equilibrium. We then conduct sensitivity analysis of the equilibrium solution with respect to price and cost parameters. We also prove the existence of a Nash equilibrium for a generalized model in which each firm has multiple local stores and a single online store. Finally, we extend the results to a multi‐period model in which each firm decides its total capacity and allocates this capacity between its local and online stores. A myopic solution is derived and shown to be a Nash equilibrium solution of a corresponding “sequential game.” © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

An EOQ model with multiple suppliers and random capacity

We consider an EOQ model with multiple suppliers that have random capacities, which leads to uncertain yield in orders. A given order is fully received from a supplier if the order quantity is less than the supplier's capacity; otherwise, the quantity received is equal to the available capacity. The optimal order quantities for the suppliers can be obtained as the unique solution of an implicit set of equations in which the expected unsatisfied order is the same for each supplier. Further characterizations and properties are obtained for the uniform and exponential capacity cases with discussions on the issues related to diversification among suppliers. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

遥测参数数据载荷状态判别集成学习方法

针对载荷单机设备遥测参数维度高、数据量大、存在类别不平衡、无法直观判别单机设备运行情况等问题,考虑到航天任务对可解释性的要求,提出一种基于信息增益参数特征选择和集成学习方法的载荷单机状态快速识别方法。采用统计量性质和信息增益子集搜索方法对遥测数据进行特征筛选降维,通过集成学习模型算法实现载荷单机设备状态的自适应识别分类。所提方法将信息增益的参数分类信息量评价准则和集成学习拟合能力强、类别不平衡下准确率高和抗噪能力强等优点相结合,兼顾模型特征和结果的可解释性,提供了重点参数发现功能。采用科学卫星任务真实载荷遥测参数数据对该方法进行了验证,整体识别准确率高于90%,少数样本亦可准确识别,整体效果可达到在轨任务要求,证明了所提方法的有效性和实用性。     

大规模 MIMO系统中用户分层变长时隙分配方法研究

大规模MIMO系统时分双工模式中分配的物理时隙长度是固定的,不能根据不同时长的信道相干时间灵活地调整长度,二者长度的不匹配导致部分时频资源的浪费,因此系统的总体容量不能达到最优。针对此问题本文提出一种用户分层变长时隙分配方法,即根据不同终端的移动性对终端进行分层,并为不同层中的移动终端灵活地分配不同时长的物理时隙,使物理时隙长度与移动终端所对应信道的相干时长相匹配,从而减少时频资源的浪费,提高了资源利用率。同时,避免了低速移动终端过频繁的信道估计,降低了信道训练序列开销,使系统的总体数据容量得到很大的提升。实验仿真结果验证了本文所提方法的有效性。     

舰载无人机光电载荷对岸射击观测与决策分析

基于舰载无人机光电载荷工作原理和岸上目标环境特点,提出了对岸射击观测的观测角、纵向坡度和横向坡度的概念,建立了纵、横向坡度和对岸收容面积计算模型;基于对光电载荷对岸收容面积的仿真,给出了对岸纵、横向收容畸变率的定义,构建了相应的计算模型;提炼出了影响对岸收容畸变率的四个因素,针对这四个因素之间的非线性关系,采用探索性分析方法,给出了针对不同的视场角、平均坡度和视轴俯角下对应的满足纵、横向畸变要求的观测角范围,供作战和训练时查用。     

A risk function for the stochastic modeling of electric capacity expansion

We present a stochastic optimization model for planning capacity expansion under capacity deterioration and demand uncertainty. The paper focuses on the electric sector, although the methodology can be used in other applications. The goals of the model are deciding which energy types must be installed, and when. Another goal is providing an initial generation plan for short periods of the planning horizon that might be adequately modified in real time assuming penalties in the operation cost. Uncertainty is modeled under the assumption that the demand is a random vector. The cost of the risk associated with decisions that may need some tuning in the future is included in the objective function. The proposed scheme to solve the nonlinear stochastic optimization model is Generalized Benders' decomposition. We also exploit the Benders' subproblem structure to solve it efficiently. Computational results for moderate‐size problems are presented along with comparison to a general‐purpose nonlinear optimization package. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:662–683, 2001     

多进制多维信号集信道容量分析及其计算

描述了信道容量的一般概念 ,具体就波形信道 ,连续信道及离散输入连续输出无记忆信道进行了分析 ,分别导出了它们的信道容量公式。结合几种常见的多进制多维调制技术MPSK、MQAM、L正交信号及其星座分析 ,给出了它们信道容量的Monte Carlo模拟以及数值积分模拟 ,同时分析了由于信号集扩展而带来的编码增益     

The value of information sharing in a two‐stage supply chain with production capacity constraints

We consider a simple two‐stage supply chain with a single retailer facing i.i.d. demand and a single manufacturer with finite production capacity. We analyze the value of information sharing between the retailer and the manufacturer over a finite time horizon. In our model, the manufacturer receives demand information from the retailer even during time periods in which the retailer does not order. To analyze the impact of information sharing, we consider the following three strategies: (1) the retailer does not share demand information with the manufacturer; (2) the retailer does share demand information with the manufacturer and the manufacturer uses the optimal policy to schedule production; (3) the retailer shares demand information with the manufacturer and the manufacturer uses a greedy policy to schedule production. These strategies allow us to study the impact of information sharing on the manufacturer as a function of the production capacity, and the frequency and timing in which demand information is shared. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

白炽灯对棉质材料的引燃性能研究

通过对不同功率白炽灯引燃100％棉质材料的研究,分析了白炽灯引燃棉质材料引发火灾的危险性。利用半导体点温计分别对不同功率白炽灯表面及棉布的温度进行记录,根据温度随时间的变化情况、可燃物被引燃情况,分析了不同功率白炽灯对棉布的引燃性能。