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991.
992.
It is common for subsidiaries of a group company to use the same types of components for producing similar products. Different subsidiary companies may well procure such components from the same suppliers. This paper studies two sourcing management models. One is the Subsidiary-Autonomous Sourcing Management (SD-ASM) where subsidiaries manage their inventories and place purchasing orders independent of each other. The other is the Headquarter-centered Common Sourcing Management (HQ-CSM) where purchasing orders of subsidiaries are processed centrally through some kind of headquarter coordination. In the SD-ASM model, each subsidiary places replenishment orders at a time interval corresponding to their economic order quantity (EOQ). In the HQ-CSM model, two purchasing order management policies are examined. One is the Order Coordination policy in which common replenishment epochs or time periods are proposed by the headquarter and the subsidiaries are encouraged to coordinate the timing of their orders based on the common replenishment epochs. The other is the Order Consolidation policy in which the subsidiaries combine the quantity of their orders and the headquarter places a combined order with the supplier. In the Order Coordination policy, classic RAND heuristic is used to find the best common replenishment epoch and the best replenishment timing of each subsidiary. In the Order Consolidation policy, the optimal order quantity of the combined order is obtained from a mathematical model. The combined order is then allocated to the subsidiaries according to a proportional allocation rule. A series of numerical studies is conducted to compare the costs of the SD-ASM and HQ-CSM policies. The results show that HQ-CSM outperforms SD-ASM in terms of cost and robustness against demand uncertainties. This achievement is largely due to the economies of process (synergistic ordering process), the economies of scale (large order quantity with price discount) and risk pooling effect (transshipments). The results also reveal that the Order Consolidation policy with a combined order always performs better than the Order Coordination policy with common replenishment epochs especially in face of high demand uncertainties and high service level in the global market. 相似文献
993.
简要介绍了利用新型干涉仪测量微机械零件表面粗糙度的原理和方法,加载结构动摩擦系数测量,微系统器件残余应力分析和半导体器件表面电位测量。 相似文献
994.
从两摆间无弹簧连接的平行双倒立摆系统特定物理结构出发,结合控制目标进行合理建模与分析,验证所建模型可行性,讨论系统能控性和参数间的关系,并设计了滑模变结构控制律.该文的理论和方法对平行单级双倒立摆的进一步研究工作具有重要意义. 相似文献
995.
针对当前可靠性预测模型的预测精度问题,提出一种增强贝叶斯组合的短期软件可靠性预测模型。该模型以基于小波分解的单个可靠性预测模型作为基本预测模型, 根据当前相邻几个失效时间间隔的预测精度,更新组合模型中各个基本预测模型的权重,解决了贝叶斯组合模型权重计算采用全部历史数据而导致某个基本预测模型权值占主导地位的缺陷,提高了贝叶斯组合模型对软件可靠性的预测精度。实验结果表明,增强贝叶斯组合预测模型的预测精度不仅优于单一的预测方法,而且也优于传统的软件组合预测模型,能显著提高软件可靠性预测的精度和模型对数据的适应性。 相似文献
996.
Lei Wang Xiaoqing Gong Yongqin Zhang Pengfei Xu Xiaojiang Chen Dingyi Fang Xia Zheng Jun Guo 《Multimedia Tools and Applications》2018,77(3):2973-2990
Chinese calligraphy is a unique visual art, and and is one of the material basis of China’s traditional cultural heritage. However, time had caused the old calligraphy works to weathering and damages, so it is necessary to utilize advanced technologies to protect those works. One of those technologies is digital imaging, and the obtained images by digital imaging can preserve the visual information of calligraphy works better, furthermore, they can be used in further researches. While the basic works for those researches are to extract the artistic features which include two elements, i.e., form and spirit. However, most of the existing methods only extract the form and ignore the characters’ spirit, especially they are insensitive to the slight variation in complex ink strokes. To solve these problems, this paper proposes an extraction method based on regional guided flter (RGF) with reference images, which is generated by KNN matting and used as the input image for RGF. Since RGF is sensitive to the slight variation of ink, so the detailed information of the inside of strokes can be detected better. Besides, unlike the past works, which filter the whole strokes, RGF filters the inside of strokes and edges in different windows respectively, which results in that the edges are preserved accurately. Results from a deployment of several famous Chinese calligraphy works demonstrate that our method can extract more accurate and complete form and spirit with lower error rate. 相似文献
997.
A closed-loop system is developed to control the weld fusion, which Is specified by the top-side and back-side bead widths of the weld pool. Because in many applications only a top-side sensor is allowed, which is attached to and moves with the welding torch, an image processing algorithm and neurofuzzy model have been incorporated to measure and estimate the top-side and back-side bead widths based on an advanced top-side vision sensor. The welding current and speed are selected as the control variables. It is found that the correlation between any output and input depends on the value of another input. This cross coupling implies that a nonlinearity exists in the process being controlled. A neurofuzzy model is used to model this nonlinear dynamic process. Based on the dynamic fuzzy model, a predictive control system has been developed to control the welding process. Experiments confirmed that the developed control system is effective in achieving the desired fusion state despite the different disturbances 相似文献
998.
针对倒立摆系统,提出了在结构上可生长的神经网络控制方案。网络利用细胞生长结构算法,在工作域中实现对状态变量的模式分类,并通过新神经元的插入实现网络规模的生长演化。在输出域中针对倒立摆控制任务采用强化Hebb学习机制,实现不同的神经元以最佳方式响应不同性质的信号刺激。仿真表明,通过神经网络自身的发育,该方案有效控制了倒立摆系统。 相似文献
999.
在简要介绍多变量模糊系统的模糊穴-穴映射(FCM-I)模型的基础上,提出了一种对多变量模糊系统进行分解的方法。此法的核心在于认为任何复杂系统的动态都是由其隐含的稳定子动态和不稳定于动态聚合而成,而系统特性则主要取决于决定性子动态的性质。并介绍了确定系统决定性子动态和基于其上的多变量模糊系统渐近分析方法。 相似文献
1000.
Zhi-Gang Wang Yong Sun Zhi-Hua Zhang 《Computers & Mathematics with Applications》2009,58(7):1408-1417
In this paper, we introduce and investigate two new classes of meromorphic multivalent functions. Such results as subordination properties, coefficient inequalities, convolution properties and integral representations are proved. Several sufficient conditions for meromorphic multivalent starlikeness and convexity are also derived. 相似文献