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131.
根据美军标MIL-STD-188-141A的规定,8FSK信号的解调是短波自动链路建立(ALE)系统的一项关键技术。通过把图像分割和聚类分析方法应用于8FSK信号的频谱分析,提出了基于模式识别的解调算法。测试结果表明,该算法对白噪声不敏感。 相似文献
132.
Partitioned pricing is a tactic in which a seller presents multiple prices for a single product or service instead of one, all-inclusive price. This research investigates effects of partitioned prices containing a variable number of price components, under varying levels of seller trustworthiness, and with or without the presentation of the total price. The results indicate that partitioning into a large number of price components, relative to a small number of price components, negatively affects perceived fairness and purchase intentions for less trustworthy, but not more trustworthy, sellers when the total price is not presented. However, partitioning into a large number of price components positively affects fairness and purchase intentions, regardless of seller trustworthiness, when the total price is presented. The research also examines effects of partitioning on price estimation and recall. 相似文献
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介绍了锁相环频率合成器的的组成及工作原理,并基于Simulink平台对双环锁相4倍频频率合成器进行了模型设计,仿真结果表明了设计的正确性及可行性。 相似文献
136.
文章对河北津西钢铁集团股份有限公司轧钢厂2000KW粗轧机机前工作辊道在生产过程中出现的问题做了详细的分析,确定其改造方案,介绍具体的改造方法,经过实践证明,小改动带来大效益。 相似文献
137.
XX公司为了降低从车间1到车间2输送物料的运输成本,在车间1和车间2之间建设了一条总长650米的链条输送线,用于物料的连续输送。由于原控制系统存在诸多缺陷,并缺乏及时的售后服务,特组织公司内外技术力量对该输送系统进行了技术研究,制定了"变频器多段固定频率控制"方案。本文主要介绍了该输送系统的功能、系统改造方案的具体设计及改造后系统的运行调试,实践证明该方案大大降低了故障率,提高了系统的稳定性。 相似文献
138.
Despite the explosive growth of the Chinese aviation sector and the major industry reforms undertaken in recent decades, the Chinese domestic market remains highly concentrated with a significant element of regulation and governmental control in areas such as market entry and airline fleet planning. In this study, we investigate the frequency strategies and aircraft choices of airlines operating in this concentrated growth market. Our empirical investigation suggests that airlines mainly accommodate rapid traffic growth by flying more frequently, although increased aircraft size also contributes to market expansion. We also find a negative relationship between market concentration and flight frequency. Due to the more balanced market structure resulting from mergers among leading airlines since 2002, there has been a moderate reduction in market concentration at route level, contributing to a 3.7% increase in traffic volume from 2002 to 2008. The results of our study suggest that Chinese travelers have yet to fully enjoy the benefits of market liberalization, and airports should prioritize increasing capacity related to aircraft movements over the accommodation of larger aircraft. 相似文献
139.
商业企业中运用JIT理论的采购模式研究 总被引:4,自引:0,他引:4
JIT及时管理对商业企业的采购管理提出了新的挑战,企业需要改变"为库存采购"的传统管理模式,提高柔性和市场响应能力,加强与供应商的信息联系,建立与供应商的新的合作模式.目前商业企业运用JIT管理方法比较滞后,尤其是在商品采购运作上.JIT理论的采购模式在商业企业中的合理运用,有利于降低商业企业的采购成本,提高商业企业物流配送效率,加快信息化建设的进程,最终实现商业企业的高效益并走上良性发展的道路. 相似文献
140.
The endo–exo problem lies at the heart of statistical identification in many fields of science, and is often plagued by spurious strong-and-long memory due to improper treatment of trends, shocks and shifts in the data. A class of models that has shown to be useful in discerning exogenous and endogenous activity is the Hawkes process. This class of point processes has enjoyed great recent popularity and rapid development within the quantitative finance literature, with particular focus on the study of market microstructure and high frequency price fluctuations. We show that there are important lessons from older fields like time series and econometrics that should also be applied in financial point process modelling. In particular, we emphasize the importance of appropriately treating trends and shocks for the identification of the strength and length of memory in the system. We exploit the powerful Expectation Maximization algorithm and objective statistical criteria (BIC) to select the flexibility of the deterministic background intensity. With these methods, we strongly reject the hypothesis that the considered financial markets are critical at univariate and bivariate microstructural levels. 相似文献