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1.
The principal component regression (PCR) is often used to forecast macroeconomic variables when there are many predictors. In this letter, we argue that it makes sense to pre-whiten the predictors before including these in a PCR. With simulation experiments, we show that without such pre-whitening, spurious principal components can appear and that these can become spuriously significant in a PCR. With an illustration to annual inflation rates for five African countries, we show that non-spurious principal components can be genuinely relevant in empirical forecasting models. 相似文献
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在复杂电磁环境下,由于民航地空通信大频偏的要求,滤波器无法滤除波道内的干扰。针对此问题,提出了一种自适应抗干扰系统设计方法。对于落在波道内且与地空通信信号有效频带不重叠的干扰,首先对通信信号进行载波频率估计,然后使用自适应滤波方法进行干扰抑制;对于落在波道内且与地空通信信号有效频带重叠的恒包络干扰,首先重构载波信号,消除对恒包络信号估计的影响,然后根据恒包络信号的特性重构干扰信号并进行干扰分离。实验结果表明,该系统设计方法在不改变民航地空通信架构的前提下,抗有效频带外干扰的能力最大可以提升23.8 dB,抗恒包络干扰的能力最大可以提升39.4 dB,从而可以大幅提高航空飞行安全水平。 相似文献
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Charlotta Sirén Vivianna Fang He Henrik Wesemann Zoe Jonassen Dietmar Grichnik Georg von Krogh 《Journal of Management Studies》2020,57(5):931-961
This study advances a theory of how different aspects of emotion regulation influence individual leader emergence in the intensely emotional context of nascent venture teams. Despite the growing amount of research on the role of leadership in the entrepreneurial process, the emergence of leaders in nascent venture teams has rarely been explored. Drawing on theories and research on leadership emergence and emotion regulation, we argue that the two aspects of emotion regulation (i.e., reappraisal and suppression) exert opposite effects on the degree to which nascent venture team members come to perceive an individual as a leader. We also theorize that team emotions arising from affective events moderate the relationship between reappraisal and leader emergence in such teams. Data from 103 nascent venture teams without prior leaders show a negative relationship between individuals’ trait disposition to suppress emotions and their emergence as leaders, and a positive relationship between their trait disposition to reappraise emotions and their emergence as leaders. Moreover, we find that negative team emotions magnify the positive association between reappraisal and leader emergence, while positive team emotions mitigate it. We discuss the implications of our findings for the literature on entrepreneurial leadership, entrepreneurial emotions, and leadership in general. 相似文献
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本文在讨论机载雷达地面杂波回波的基础上,分析了AMTI和ADPCA系统的性能。对这两个系统从原理上,并利用计算机模拟结果及实验结果进行了比较。本文将有助于工程实现。 相似文献
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利用小波包理论提出了一种快速、准确地识别并且抑制多音干扰的有效方法。该方法利用小波包理论将多音干扰的各条谱线逐个定位,然后通过功率谱分析的方法来识别多音干扰的存在区间,最后将被干扰污染的区间逐个切除并反向重构接收到的信号。实验证明该方法的误比特率性能在强干扰时要优于以前的FFT域切割法。 相似文献
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本文依据行为和态度两个维度对顾客虚假忠诚的内涵进行了界定,并指出其与顾客真正忠诚的区别。通过对现有文献的梳理。将顾客虚假忠诚的前置因素划分为态度、行为驱动因素和外部、内部情景调节因素,通过深入分析,提出了顾客虚假忠诚的形成机理模型,并提出了维系现有顾客的策略建议。 相似文献
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固定镜头下视频序列中的运动汽车目标的检测、分割、跟踪及计数等底层视觉问题进行了研究,提出了计算交通流量的算法。仿真实现表明:此算法可以有效的去噪、检测目标并计数。 相似文献
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Statistical offices are concerned with problems of protecting confidential information when publishing data in statistical tables. One method to avoid disclosure is the method of cell suppression, in which the values of the sensitive cells in the table are suppressed from publication. To prevent the values of the sensitive cells from being calculated from the tables totals, additional suppressions are necessary. The problem of minimizing the loss of information caused by the additional suppressions is a difficult optimization problem. We present and compare the performance of some heuristics for cell suppression for general three-dimensional tables. 相似文献