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271.
A novel gradient approach for optimal design and sensitivity analysis of EWMA control charts 下载免费PDF全文
Conventional control charts are often designed to optimize out‐of‐control average run length (ARL), while constraining in‐control ARL to a desired value. The widely employed grid search approach in statistical process control (SPC) is time‐consuming with unsatisfactory accuracy. Although the simulation‐based ARL gradient estimators proposed by Fu and Hu [Manag Sci 45 (1999), 395–413] can alleviate this issue, it still requires a large number of simulation runs to significantly reduce the variance of gradient estimators. This article proposes a novel ARL gradient estimation approach based on integral equation for efficient analysis and design of control charts. Although this article compares with the results of Fu and Hu [Manag Sci 45 (1999), 395–413] based on the exponentially weighted moving average (EWMA) control chart, the proposed approach has wide applicability as it can generally fit into any control chart with Markovian property under any distributions. It is shown that the proposed method is able to provide a fast, accurate, and easy‐to‐implement algorithm for the design and analysis of EWMA charts, as compared to the simulation‐based gradient estimation method. Moreover, the proposed gradient estimation method facilitates the computation of high‐order derivatives that are valuable in sensitivity analysis. The code is written in Matlab, which is available on request. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 223–237, 2014 相似文献
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273.
海拔对离心泵吸入性能影响较大,但对应关系不明确。为定量分析海拔与离心泵吸入性能的关系,需进行泵高原工作吸入性能实验。海拔与真空度关系密切,利用控制泵吸入口真空度的方法,开展泵高原工作吸入性能模拟实验,获取各工况下泵吸入口持液率数据,并绘制曲线图。实验结果表明:海拔每升高500 m,泵吸入口持液率下降2%~5%;随着海拔的提升,泵吸入性能下降速率加快,工作状态趋于不稳定。 相似文献
274.
氧气体积分数对油气爆炸特性的影响 总被引:1,自引:0,他引:1
作为燃烧和爆炸三要素之一,氧气体积分数的控制对于爆炸事故的防治具有重要意义。实验研究了氧气体积分数对汽油蒸气-空气混合物(简称油气)爆炸极限和爆炸压力的影响。结果表明:随着氧气体积分数的降低,油气爆炸下限呈一阶指数规律缓慢增大,油气爆炸上限呈线性规律迅速减小;爆炸极限范围由0.92%~3.76%缩小为1点,该爆炸极限临界点为1.22%,对应的临界氧气体积分数为11.4%;油气的最大爆炸压力和最大压力上升速率随着氧气体积分数的降低而减小,油气体积分数越大,氧气体积分数影响越显著。 相似文献
275.
棉花堆垛火灾扑救对策探讨——以临汾中储棉仓库火灾扑救为例 总被引:2,自引:0,他引:2
朱江 《中国人民武装警察部队学院学报》2014,30(12):27-29
棉花具有易燃、阴燃特性,其堆垛起火后火势蔓延迅速,容易在短时间内形成大面积、立体火灾,扑救困难。阐述了棉花堆垛火灾的特点,探讨了棉花堆垛火灾处置的对策,分析了扑救棉花火灾应注意的事项,并简要介绍了棉花仓库火灾防范措施。 相似文献
276.
本文总结了在实际工作中摸索的 BASIC 主程序与汇编语言子程序连接的新方法。它采用 DEBUG 的 W 命令直接将汇编子程序的机器代码存入磁盘的扇区。再在 BASIC 环境下调用 DOS 中断25H,将汇编子程序机器码装入内存,然后可由CALL 语句或由 USR 函数调用。该方法可以简化 BASIC 主程序和汇编语言子程序的调试和连接过程。 相似文献
277.
姜礼平 《海军工程大学学报》1990,(3)
本文利用四种时间序列模型,即自回归模型、组合模型、疏系数自回归模型、门限自回归模型,分别对时间序列分析中一组有名数据,即加拿大山猫数据,进行模型拟合,并对得到的四个模型及预报结果进行了分析和比较。 相似文献
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279.
In order to accurately describe the transverse relaxation characteristic and stress relaxation modulus of HTPB coating during pre-strain thermal aging process, a one month thermal aging test was carried out at 70 C with pre-strain of 0%, 3%, 6% and 9%, respectively. The low-field 1H NMR and stress relaxation modulus tests were carried out for HTPB coating at different aging stages. The stress relaxation model considering the molecular chains was proposed according to the changes of crosslinking chain and dangling chain of HTPB coating during pre-strain aging. The results showed that with the increase of aging time, the decay rate of transverse relaxation curve became faster, the transverse relaxation time decreased, the value of combined parameter qMrl increased, the proportion of crosslinking chain decreased, while the proportion of dangling chain increased. Moreover, the stress relaxation modulus increased, the crosslinking network structure of HTPB coating became denser and the degree of cross-linking increased. At the initial aging stage, the pre-strain will destroy the crosslinking network structure of HTPB coating to a certain extent. With the increase of aging time, the effect of pre-strain will gradually weaken and the influence of aging on materials will gradually increase. The correlations between the stress relaxation model considering the molecular chains and the test results were more than 0.9950, which can accurately describe the stress relaxation modulus of HTPB coating during the pre-strain thermal aging process. 相似文献
280.
The multi-armored target tracking (MATT) plays a crucial role in coordinated tracking and strike. The occlusion and insertion among targets and target scale variation is the key problems in MATT. Most state-of-the-art multi-object tracking (MOT) works adopt the tracking-by-detection strategy, which rely on compute-intensive sliding window or anchoring scheme in detection module and neglect the target scale variation in tracking module. In this work, we proposed a more efficient and effective spatial-temporal attention scheme to track multi-armored target in the ground battlefield. By simulating the structure of the retina, a novel visual-attention Gabor filter branch is proposed to enhance detection. By introducing temporal information, some online learned target-specific Convolutional Neural Networks (CNNs) are adopted to address occlusion. More importantly, we built a MOT dataset for armored targets, called Armored Target Tracking dataset (ATTD), based on which several comparable experiments with state-of-the-art methods are conducted. Experimental results show that the proposed method achieves outstanding tracking performance and meets the actual application requirements. 相似文献