Optimal selection with alternative information

This article examines the problem of optimally selecting from several unknown rewards when there are given alternative, costly sources of information. The optimal rule, indicating the information to be purchased and the reward to be selected, is specified as a function of the decision maker's prior probabilities regarding the value of each alternative. The rule is surprisingly complex, balancing prior beliefs, the “informativeness” of the relevant information system, and the cost of acquiring information.     

The asymptotic joint distribution of the state occupancy times in an alternating renewal process

An alternating renewal process starts at time zero and visits states 1,2,…,r, 1,2, …,r 1,2, …,r, … in sucession. The time spent in state i during any cycle has cumulative distribution function F_i, and the sojourn times in each state are mutually independent, positive and nondegenerate random variables. In the fixed time interval [0,T], let U_i(T) denote the total amount of time spent in state i. In this note, a central limit theorem is proved for the random vector (U_i(T), 1 ≤ i ≤ r) (properly normed and centered) as T → ∞.     

Optimal replacement for fault-tolerant systems

We consider the optimal replacement problem for a fault tolerant system comprised of N components. The components are distingushable, and the state of the system is given by knowing exactly which components are operationl and which have failed. The individual component failure rates depend on the state of the entire system. We assume that the rate at which the system produces income decreases as the system deteriorates and the system replacement cost rises. Individual components cannot be replaced. We give a greedy-type algorithm that produces the replacement policy that maximizes the long-run net system income per unit time.     

Multi-period airline overbooking with multiple fare classes

Consider a multi-period multi-fare class airline overbooking problem that relates to a single-leg flight. Passengers may cancel their reservations at any time, including being no-shows at flight-time. Canceling passengers receive a refund that depends on their fare class, e.g., supersaver, coach, etc. At flight-time, the airline bumps passengers in excess of flight capacity and pays a penalty for so doing. A continuous state-space dynamic programming model is developed in which the state is the numbers of reservations currently on hand in each fare class. In each period, reservation requests occur in only one fare class and the fraction of reservations canceling in each class is independent of the number of reservations therein. A booking-limit policy is optimal, i.e., in each period the airline accepts reservation requests up to a booking limit if the number of initial reservations in the fare class is less than the booking limit, and declines reservation requests otherwise. The booking limits for each class depend on the numbers of reservations in the other classes. When there are two fare classes the optimal booking limits in each class decrease with the number of reservations in the other class. © 1996 John Wiley & Sons, Inc.     

Heuristic modeling of supply availabilities in large networks

The objective of this article is to describe heuristic solutions to the problem of modeling inventories at each node of a large network in the context of a computer simulation model of that network. The heuristic solutions are compared with the mathematical solution which is too unwieldy for use in a simulation model. The Weibull cumulative distribution is used as an approximation for the heuristic models. We question whether the good performance of the Weibull is coincidence or perhaps mathematically justifiable.     

调频连续波ISAR目标微多普勒特征分析

分析了调频连续波逆合成孔径雷达(FMCW-ISAR)的回波信号特性,讨论了脉冲持续时间内目标连续运动引起的多普勒频移对成像的影响,推导出导致一维距离像主瓣展宽和走动的相位因子,并进一步研究了该相位因子对基于调频连续波逆合成孔径雷达的目标微多普勒特征的影响,在此基础上讨论了调频连续波逆合成孔径雷达目标微多普勒特征与脉冲式逆合成孔径雷达目标微多普勒特征的主要区别.最后的仿真试验验证了理论分析的正确性.     

对高校招生宣传工作的思考

本文根据我国西部高校招生宣传的实践,对招生宣传工作的规律和西部学校宣传工作的特色进行了阐述。