Optimal control of a revenue management system with dynamic pricing facing linear demand

This paper considers a dynamic pricing problem over a finite horizon where demand for a product is a time‐varying linear function of price. It is assumed that at the start of the horizon there is a fixed amount of the product available. The decision problem is to determine the optimal price at each time period in order to maximize the total revenue generated from the sale of the product. In order to obtain structural results we formulate the decision problem as an optimal control problem and solve it using Pontryagin's principle. For those problems which are not easily solvable when formulated as an optimal control problem, we present a simple convergent algorithm based on Pontryagin's principle that involves solving a sequence of very small quadratic programming (QP) problems. We also consider the case where the initial inventory of the product is a decision variable. We then analyse the two‐product version of the problem where the linear demand functions are defined in the sense of Bertrand and we again solve the problem using Pontryagin's principle. A special case of the optimal control problem is solved by transforming it into a linear complementarity problem. For the two‐product problem we again present a simple algorithm that involves solving a sequence of small QP problems and also consider the case where the initial inventory levels are decision variables. Copyright © 2006 John Wiley & Sons, Ltd.     

头皮冠状切口的并发症及其防治

目的：对采用头皮冠状切口所引发的并发症进行分析，探讨防治策略。方法：对我科2003-01～2006—07应用头皮冠状切口行颅颌面骨折修复重建、颌面部肿瘤切除与缺损修复、先天性颅颌面畸形矫正的221例中发生并发症的40例进行分析总结。结果：18例出现头皮麻木及感觉异常，9例有较宽切口瘢痕，6例出现脱发，4例发生颞窝凹陷，2例发生头皮下血肿，2例出现单侧面神经颞支损伤，1例发生鼻眶区肥厚。结论：头皮冠状切口具有切口隐蔽、面部疤痕不明显，显露充分的优点，但对其并发症也不容忽视。应根据具体情况选择合适的切口类型，术中精细的解剖、神经血管的良好保护以及正确的缝合方法可减少并发症的发生。     

61例流行性出血热患者临床各期血液流变学观察

通过血液流变学的检测,观察61例流行性出血热患者临床各期的改变。发现出血热患者临床各期,全血粘度的均数都高于正常对照的上限值。五期中少尿期升高不明显,发热期和多尿期明显升高。红细胞聚集指数各期均有显著性升高,提示出血热整个病程是DIC的形成过程。通过动态观察临床各期血液流变学的检测可及时正确地指导临床工作。     

Discrete time optimal control of linear time-delay systems

A discrete time optimal control for linear time-delay systems is developed to ensure that all closed-loop eigenvalues will lie inside a circular region centred at (β;, 0) with radius α. It is shown that by suitable manipulations the problem can be reduced to a standard discrete time quadratic regulator problem. An illustrative example is included to demonstrate the applicability of the proposed method.     

Dorsal and ventral dopaminergic innervation of the spinal cord: Functional implications

Several studies have demonstrated that a descending dopaminergic pathway innervates the dorsal and the intermediate gray matter of the spinal cord and have suggested that this pathway is involved in pain modulation and in the control of autonomie functions. Other studies have also demonstrated the presence of dopamine (DA) and DA metabolites as well as of DA receptors in the ventral cord. There is also evidence for the implication of DA in the control of motor functions at the spinal level. The occurrence of a dopaminergic innervation in the ventral horn has been, however, disputed until recently. But recent work has demonstrated that the motoneural cell groups in the ventral horn (lamina IX) are a target for descending dopaminergic fibers. In addition, the possibility that DA is a mediator of primary afferent fibers has also been postulated. Finally, the occurrence of dopaminergic cell bodies has been suggested in the spinal cord. This indicates that DA is probably implicated in a complex manner in spinal functions. In the present paper the possible involvement of DA in sensory and in motor functions at spinal level will be discussed in view of neurochemical observations made in polyarthritic rats, in which pain-related behavior and reduction of locomotor activity associated with a marked decrease in mobility, are observed.     

Evaluation of bedside blood glucose monitoring by the phlebotomy team in an acute general care hospital

A feasibility study was undertaken to evaluate laboratory phlebotomists performing bedside glucose monitoring (BGM) over a 3-month period on a medical and surgical floor. Specific questions included: feasibility of providing testing on a 24-h basis, accuracy, appropriate utilization, effect on patient care, and an analysis of cost. In all, 1975 tests were performed on 114 patients. BGM results were within 15% of the laboratory's result 97% of the time. Patient and physician satisfaction was high. Although the cost of BGM is slightly higher than a laboratory glucose test, its use appeared to reduce the length of hospital stay by 0.47 days. Practical information on initiating a highly successful BGM program is provided.     

Alcohol controls and Aboriginal society: The effects of the Northern Territory restricted areas legislation

The “restricted areas” provisions of the Northern Territory Liquor Act constitute a preventative policy aimed at reducing the effects of alcohol abuse, particularly on Aboriginal communities. Under the provisions, communities can apply to be declared “dry” or semi-restricted with respect to liquor. Since their inception in 1979, the provisions have given rise to continuing controversy. This paper addresses some of the issues associated with the controversy. Patterns of alcohol consumption on “dry”, semi-restricted and unrestricted communities are compared, and the incidence of apprehension for public drunkenness before and after restricted area declarations is examined. The paper also discusses the provisions under which vehicles implicated in acts of illicit “grog-running” are forfeited to the NT Government. It is concluded that the restricted area provisions are associated with reduced levels of alcohol consumption and apprehensions for drunkenness, and are therefore beneficial in outcome. However, it is also argued that at present the provisions are flawed in that, while some aspects serve to promote community control over alcohol consumption, other elements have the effect of undermining community control and responsibility.     

异搏定防治流行性出血热初期急性肾功能衰竭的疗效观察

在综合疗法的基础上加用异搏定3～5天治疗流行性出血热(EHF)发热后期病人41例,在尿蛋白转阴、越期率,特别是越少尿期平明显优于对照组,但对 BUN 水平的影响与对照组无异,异搏定对防治 EHF 急性肾衰具有一定疗效。     

调整给药时间减轻顺铂肾毒性的研究

目的　观察不同给药时间对顺铂肾毒性的影响。　方法　 1 6例癌症患者分为两组各 8例 ,分别在上午 1 0时或下午 8时静滴 6 0mg m2 顺铂 ,3～ 4周后作第 2周期化疗时交换给药时间 ,以尿 β2 微球蛋白浓度作为肾小管功能改变的指标。　结果　治疗前两组的尿 β2 微球蛋白浓度均在 2 0 0 μg L以下。治疗后 ,上午 1 0时给药组的尿β2 微球蛋白浓度在第 1周期为 4 96± 6 6 μg L ,第 2周期为 5 0 4± 74 μg L ,下午 8时给药组分别为 2 77± 4 3μg L(t=3.6 6 ,P <0 .0 1 )和 2 83± 39μg L(t=3.6 3,P <0 .0 1 )。 　结论　不同时间给药对顺铂的肾毒性有显著影响 ,下午 8时给药可明显减轻顺铂的肾毒性。