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411.
软体油罐罐体与罐内液体的相互作用为典型的流构耦合问题。采用有限元分析软件LS—DYNA,首先通过控制体积法得到了软体油罐充液后的有限元模型,然后采用任意拉格朗日欧拉算法分析了地面倾斜时软体油罐的形态表现,研究了储液体积恒定时,地面倾角与储液高度的关系。提出了倾斜地面上软体油罐体积计算的修正公式,模拟情况和实际情况比较接近,为软质储液容器的测量及误差修正提供了重要的参考依据。 相似文献
412.
In this article, we present a multistage model to optimize inventory control decisions under stochastic demand and continuous review. We first formulate the general problem for continuous stages and use a decomposition solution approach: since it is never optimal to let orders cross, the general problem can be broken into a set of single‐unit subproblems that can be solved in a sequential fashion. These subproblems are optimal control problems for which a differential equation must be solved. This can be done easily by recursively identifying coefficients and performing a line search. The methodology is then extended to a discrete number of stages and allows us to compute the optimal solution in an efficient manner, with a competitive complexity. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 32–46, 2016 相似文献
413.
This article investigates the impact of timing on sellers' information acquisition strategies in a duopoly setting. Market uncertainty is captured by a representative consumer who has a private taste for the product's horizontal attribute, and both sellers can acquire this information either before (ex‐ante acquisition) or after (ex‐post acquisition) observing their own product qualities. We identify several conflicting effects of information acquisition that vary significantly in its timing and market characteristics. In the monopoly scenario, information acquisition is unambiguously beneficial and ex‐ante acquisition is the dominant option, because it helps a seller not only design the proper product but also craft better pricing strategy. By contrast, when there is competition, information acquisition eliminates the buffer role of market uncertainty and leads to the fiercest production or pricing competition, which makes the subsequent effects of acquisition detrimental, and a seller's payoff is nonmonotonic in terms of its acquisition cost. Moreover, compared with the ex‐ante information acquisition, ex‐post information acquisition normally generates higher sellers' equilibrium payoffs by postponing the timing of acquisition and maintaining product differentiation. Nonetheless, ex‐post information acquisition also provides the seller with greater acquisition incentive and occasionally makes him worse off than that in the ex‐ante scenario. Thus, in a competitive environment, having the option of information acquisition and flexibility in its timing can be both detrimental and irresistible. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 3–22, 2016 相似文献
414.
In various scenarios, consumers may become satiated with products, and the degree of satiation is directly associated with their prior experiences. Confronted with consumer satiation, the seller is unable to either identify consumers who have a higher likelihood of being satiated ex ante or distinguish satiated from non‐satiated consumers ex post. Therefore, the seller should address dynamic selling, valuation uncertainty, and quantity decisions, all of which are important operational issues. We consider a two‐period problem in which consumer types are influenced by their prior consumption experiences. Faced with these consumers, the seller intends to optimize quantities and adjust the prices of the products in each period to maximize revenue. We find that the seller may reduce ex ante production quantity as some consumers become satiated. Moreover, the ex ante quantity is first decreasing and then increasing with regard to the satiation rate. Furthermore, two‐period information asymmetries may provide a rationale for upward distortion in quantity when consumer preferences are highly sensitive to first‐period consumption. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 386–400, 2016 相似文献
415.
管道检测机器人的测力定位法理论与方法 总被引:1,自引:1,他引:0
介绍并分析了管道检测机器人的定位现状,并针对它们的不足,根据牛顿力学和运动学定律提出了管道机器人的测力定位法.对测力定位法的性能进行了分析,发现误差有时间的累积性,并以时间的二次方递增.指出了它和光电码盘定位法的综合运用将是有效解决长距离输油管道机器人的高精度的独立定位问题的最佳切入点.最后,对测力定位法在整个管道检测机器人的检测、定位中的应用进行了分析,并给出了应用结构流程图. 相似文献
416.
基于小波变换和Feistel密码结构的图像置乱技术 总被引:1,自引:0,他引:1
由于图像信息在网络进行传输时,很容易被非法截取.而隐写术能起到保护机密信息免受攻击的作用,因而得到了广泛的研究和应用.置乱技术虽然是隐写术的预处理过程,但它在隐写术中起着非常重要的作用.提出了一种新的基于小波变换和Feistel密码结构的图像置乱方法,其置乱的对象是载体图像中的小波系数,置乱算法基于Feistel密码结构,密钥采用变形约瑟夫遍历产生,属于"一次一密"的密钥生成.将该方法用于油料信息图像隐藏实验取得了良好的效果. 相似文献
417.
为了解决拦截器导引头采用侧窗制导的问题,给出了拦截器的轨道拦截运动方程.针对需要保持侧窗视线角稳定的要求,根据以视线角和视线角速度为变量的状态方程,采用了自适应滑模变结构控制的制导律,并根据拦截器轨控发动机和拦截器运动学的数学模型进行了仿真,得到了较好的拦截效果,验证了制导律的正确性. 相似文献
418.
419.
易金务 《军队政工理论研究》2008,9(6)
目前,正在全军部队广泛开展的关爱独生子女、关爱计划生育家庭、关爱官兵生殖健康的"三关爱"活动,是人口和计划生育事业的又一重要里程碑。为提升"三关爱"活动的质量和水平,必须把促进人的全面发展作为根本目标,把发挥官兵的主体作用作为根本途径,把维护官兵的合法权益作为根本职责,坚持权利与义务的统一、激励与约束的统一、服务与管理的统一,始终把以人为本贯穿到"三关爱"活动的各个环节和全过程。 相似文献
420.