Value management of diagnostic equipment with cancelation,no‐show,and emergency patients

Magnetic resonance imaging and other multifunctional diagnostic facilities, which are considered as scarce resources of hospitals, typically provide services to patients with different medical needs. This article examines the admission policies during the appointment management of such facilities. We consider two categories of patients: regular patients who are scheduled in advance through an appointment system and emergency patients with randomly generated demands during the workday that must be served as soon as possible. According to the actual medical needs of patients, regular patients are segmented into multiple classes with different cancelation rates, no‐show probabilities, unit value contributions, and average service times. Management makes admission decisions on whether or not to accept a service request from a regular patient during the booking horizon to improve the overall value that could be generated during the workday. The decisions should be made by considering the cancelation and no‐show behavior of booked patients as well as the emergency patients that would have to be served because any overtime service would lead to higher costs. We studied the optimal admission decision using a continuous‐time discrete‐state dynamic programming model. Identifying an optimal policy for this discrete model is analytically intractable and numerically inefficient because the state is multidimensional and infinite. We propose to study a deterministic counterpart of the problem (i.e., the fluid control problem) and to develop a time‐based fluid policy that is shown to be asymptotically optimal for large‐scale problems. Furthermore, we propose to adopt a mixed fluid policy that is developed based on the information obtained from the fluid control problem. Numerical experiments demonstrate that this improved policy works effectively for small‐scale problems. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 287–304, 2016     

某加油车液压系统的温升控制

温升控制是液压系统设计的重要内容，其效果好坏直接影响着液压系统工作的可靠性。针对某加油车液压系统连续工作时间长、结构紧凑等特点，设计了一种新型的“油冷蛇形管”式液压油温控制系统，即将加油车自身输转的柴油导入液压油箱内的冷却管，对液压油实施强制冷却。经试验验证，取得了良好的温控效果。该方法取消了冷却水源，简化了结构，并达到了控制油温的目的，对类似系统的设计具有较好的借鉴意义。     

基于ARM的LED指挥控制终端的设计与实现

LED显示屏是现代社会发布信息的一种重要方式,通过LED显示屏可以播放视频、文字等不同形式的信息,为人们传达最直观的视觉信息。随着科学技术的不断发展,LED显示屏的应用也日渐广泛,尤其是军事上的应用,比如基于LED显示屏的各种级别指挥控制终端的设计和运用,具有更为深入的研究价值。而ARM处理器是实现LED显示屏控制系统有效运行的基础,主要针对基于ARM的LED显示屏指挥控制终端系统的设计与实现的相关问题进行了探讨。     

多级感应线圈发射器测控系统设计

将电枢加速到较高速度，通常需要多级感应线圈连续加速；而提高多级感应线圈发射器的发射效率，则要求在电枢处于驱动线圈最佳触发位置时，电容器组同步放电。同时，需要采集发射过程中电枢的速度、电源的放电电压和放电电流等数据。因此，研制合理的测控系统是多级感应线圈发射器的关键。     

基于线性模型跟随的重构飞行控制律设计

线性模型跟随控制是一种传统的控制方法，通过对增益的调整，使实际受控系统的输出跟随参考模型的输出，以达到理想的静态、动态特性。将线性模型跟随控制引入自修复飞行控制系统的重构控制中，针对发生舵面故障的飞行控制系统，设计模型跟随控制律，给出仿真实例。结果表明，该方法具有可行性和有效性。     

坦克火控系统自动跟踪功能关键技术

结合现代军事发展,分析了现代坦克火控系统发展自动跟踪技术的必要性;根据我军现装备的坦克火控系统所具有的自动跟踪功能,分析了自动跟踪的相关技术,电视跟踪技术的原理,图像匹配法的涵义;系统介绍了电视跟踪中图像匹配法识别和跟踪目标,介绍了目标自动跟踪系统对目标识别和判定的一种具体方法.     

空空导弹越肩发射初制导转弯控制与仿真

针对空空导弹越肩发射初制导俯仰平面180°转弯,提出了一种基于最优控制理论的最优转弯方法,该方法是确定一个最佳推力方向角,使转弯完成时导弹的末端速度最大。建立了简化的用于姿态控制的姿态动力学模型,采用反作用喷气控制系统(RCS)设计了导弹的姿态控制律。对空空导弹180°转弯的飞行过程进行了仿真并给出分析结果。     

Robustness of efficient server assignment policies to service time distributions in finite‐buffered lines

We study the assignment of flexible servers to stations in tandem lines with service times that are not necessarily exponentially distributed. Our goal is to achieve optimal or near‐optimal throughput. For systems with infinite buffers, it is already known that the effective assignment of flexible servers is robust to the service time distributions. We provide analytical results for small systems and numerical results for larger systems that support the same conclusion for tandem lines with finite buffers. In the process, we propose server assignment heuristics that perform well for systems with different service time distributions. Our research suggests that policies known to be optimal or near‐optimal for Markovian systems are also likely to be effective when used to assign servers to tasks in non‐Markovian systems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

The effects of model parameter deviations on the variance of a linearly filtered time series

We consider a general linear filtering operation on an autoregressive moving average (ARMA) time series. The variance of the filter output, which is an important quantity in many applications, is not known with certainty because it depends on the true ARMA parameters. We derive an expression for the sensitivity (i.e., the partial derivative) of the output variance with respect to deviations in the model parameters. The results provide insight into the robustness of many common statistical methods that are based on linear filtering and also yield approximate confidence intervals for the output variance. We discuss applications to time series forecasting, statistical process control, and automatic feedback control of industrial processes. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

基于模型跟踪变结构控制的飞行重构控制律设计

提出一种基于模型跟踪变结构控制的飞行重构控制律的设计方法.利用该方法能实现受控对象对理想模型较高精度的跟踪,使重构飞行控制系统具有较好的控制性能.首先设计了一个比例-积分滑模面以确保消除稳态误差,采用极点配置技术使滑模具有良好的动态品质,其次利用饱和控制技术来减少变结构控制引起的抖振现象,最后以某型飞机纵向飞行控制系统为例进行了相应的数字仿真.结果表明重构系统不仅实现了无抖振模型跟踪,而且还具有较强的鲁棒性.