Browsing by Author "Guo, Wei"

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    Comparative analysis of markup and markdown pricing policies in revenue management problems
    (2014-04) Guo, Wei
    It is a common practice for many industries to bolster sales and revenue through dynamic pricing strategies. For instance, markup pricing is especially prevalent in the commercial airline industry. Meanwhile, for products sold on a seasonal basis, many stores generally decrease their prices toward the end of the season. In this thesis, we compare the expected revenue that can be generated from two representative pricing policies: markup only and markdown only, in a continuoustime single product revenue management model over a finite horizon. In our model, the initial inventory is fixed and there is no replenishment opportunity during the selling period. The demand follows a homogeneous Poisson process whose rate is controlled by price only. The decisions are to select a price from a set of predetermined prices at each time during the selling period. We show that the markdown policy is superior to the markup policy when the inventory level is low and the remaining time is ample; when the remaining time is short, the markup policy is superior. Our findings complement the previous studies in each of these policies and provide valuable insights for practitioners to choose among different pricing strategies. We verify our findings through numerical tests.
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    Optimal UAV flights for seeability and endurance in winds.
    (2010-12) Guo, Wei
    Video-equipped unmanned aerial vehicles (UAVs) are highly useful in missions of surveillance, monitoring, and sensing. In these flights, the UAVs must maintain the ability to see the targets as well as to save energy for prolonged endurance. This paper examines basic patterns of UAV flights that can maximize its ability to “see” targets or seeability and/or minimize power consumptions to assist UAV mission planning. In this paper, a point-mass model is used to describe UAV motions. A seeability model is established that peaks when the UAV is flying at a certain angle from the normal vector perpendicular to the surface of the target. UAV flights are formulated as nonlinear periodic optimal control problems. The performance indices are selected to maximize the average seeability, to minimize the average power consumption, or to achieve a balance of the two. Motion constraints due to UAV performance capabilities and safety are imposed. The effects of different levels of constant wind velocities are considered. These nonlinear optimal control problems are converted into parameter optimization for numerical solutions. Extensive numerical solutions are obtained for UAV level flights with constant airspeeds and variable airspeeds, as well as three-dimensional flights. Clear tradeoffs between maximum seeability and minimum power are established.