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421.
Mixed censoring is useful extension of Type I and Type II censoring and combines some advantages of both types of censoring. This paper proposes a general Bayesian framework for designing a variable acceptance sampling scheme with mixed censoring. A general loss function which includes the sampling cost, the time‐consuming cost, the salvage value, and the decision loss is employed to determine the Bayes risk and the corresponding optimal sampling plan. An explicit expression of the Bayes risk is derived. The new model can easily be adapted to create life testing models for different distributions. Specifically, two commonly used distributions including the exponential distribution and the Weibull distribution are considered with a special decision loss function. We demonstrate that the proposed model is superior to models with Type I or Type II censoring. Numerical examples are reported to illustrate the effectiveness of the method proposed. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 相似文献
422.
In the classical EPQ model with continuous and constant demand, holding and setup costs are minimized when the production rate is no larger than the demand rate. However, the situation may change when demand is lumpy. We consider a firm that produces multiple products, each having a unique lumpy demand pattern. The decision involves determining both the lot size for each product and the allocation of resources for production rate improvements among the products. We find that each product's optimal production policy will take on only one of two forms: either continuous production or lot‐for‐lot production. The problem is then formulated as a nonlinear nonsmooth knapsack problem among products determined to be candidates for resource allocation. A heuristic procedure is developed to determine allocation amounts. The procedure decomposes the problem into a mixed integer program and a nonlinear convex resource allocation problem. Numerical tests suggest that the heuristic performs very well on average compared to the optimal solution. Both the model and the heuristic procedure can be extended to allow the company to simultaneously alter both the production rates and the incoming demand lot sizes through quantity discounts. Extensions can also be made to address the case where a single investment increases the production rate of multiple products. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004. 相似文献
423.
为了解决部件阶段依赖性与共因失效给系统可靠性分析带来的复杂性,针对多阶段共因失效任务系统,结合GO法易于处理有时序、含共因失效系统可靠性分析的特点,首先,将前一阶段的输出信号作为后一阶段的输入信号,建模时首尾连接各阶段模型,建立整个任务系统的隐性GO模型;其次,在进行各信号流状态组合运算时,融入阶段代数处理部件的阶段依赖性;再次,用隐性共因失效分析,将共因失效对系统的影响在状态组合的定量分析中表达出来,得到所需系统可靠性指标;最后,与基于二元决策图的算法进行对比验证。结果表明:GO法可以简捷、准确地处理多阶段共因失效任务系统可靠性评估问题。 相似文献
424.
基于强迫换流原理的新型真空直流限流断路器 总被引:2,自引:0,他引:2
提出了一种基于现有强迫换流型真空直流断路器的改进方案,并通过在高速真空开关两端并联反向续流二极管,使真空开关在电弧电流强迫过零后由于二极管的续流作用得到零电压介质强度恢复时间,提高了真空灭弧室电流过零后的介质强度恢复速度,使真空开关得以在小间隙下分断高上升率的短路电流,提高了传统真空直流断路器的限流、分断能力。设计了限流断路器样机,进行了短路分断试验。试验结果表明:所设计的限流断路器能将最大上升率为20A/μs的短路电流限流至10kA以下,限流分断时间小于1.1ms,满足了现代舰船极限短路故障的保护要求。 相似文献
425.
提出一种面向多核处理器的并行PCA-SIFT算法,采用数据级并行方法实现并行的特征提取和特征点匹配,将计算任务分配到各个DSP核并行处理,充分开发多核处理器的多级并行性.实验结果表明,并行PCA-SIFT算法对各种不同图像形变的图像具有良好的适应性,具有接近串行PCA-SIFT算法的图像匹配能力,平均加速比达3.12. 相似文献
426.
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428.
晚清以来,中国社会经历了由传统封建社会向近代社会的全方位社会转型,军事变革与社会转型发生着千丝万缕的联系。解读晚清军事与近代社会转型的内在联系,有利于更好的理解那段历史。 相似文献
429.
在研究W eb服务技术的基础上,利用.NET开发平台设计了装备管理系统中的器材库存管理系统,证明了W eb服务技术的可行性和有效性。 相似文献
430.
Huan-huan Sun Yi-bo Ren Yang Feng Hao-qiang Ba Dong Chen Chun-juan Xia Hao-wei Wang 《防务技术》2021,17(3):1062-1070
Lightweight hybrid structures of Al MMCs and titanium alloy dissimilar materials have great prospect in the defence industry application. So, it is necessary to join Al MMCs with Ti metal to achieve this structural design. In this work, in-situ TiB2/7050 composite and TA2 were firstly attempted to join by TIG welding-brazing technique. The result was that the intact welding-brazing butt joint was successfully fabricated. The joint presents dual characteristics, being a brazing on TA2 side and a welding on TiB2/7050 side. At brazing joint side, ER4043 filler metal effectively wets on TA2 under TIG heating condition, and a continuous interfacial reaction layer with 1—3μm is formed at welded metal/TA2 interface. The whole interfacial reaction layers are composed of Ti(AlSi)3 intermetallic compounds (IMCs), but their morphologies at the different regions present obvious distinguishes. The microhardness of the reaction layers is as much as 141—190 HV. At welding joints side, the fusion zone appears the equixaed crystal structure, and the grain sizes are much smaller than those of welded metal, which is attributed to the effect of TiB2 particulates from the melted TiB2/7050 on acceleration formation and inhibiting growth for the new crystal nucleus. The tensile test results show that average tensile strength of the optimal welding-brazing joint is able to achieve 138 MPa. The failure of the tensile joint occurs by quasi-cleavage pattern, and the cracks initiate from the IMCs layer at the groove surface of TA2 and propagate into the welded metal. 相似文献