研发要素具有自主性、 趋优性,高技术产业的研发投入要素往往有扭曲现象.利用2009—2018年中国省际面板数据,采用生产函数法测算研发人员和研发资本要素的市场扭曲指数,并运用动态广义矩估计法实证分析研发要素市场扭曲对高技术产业创新绩效的影响.结果表明:两种研发要素市场均存在不同程度的扭曲态势,且研发人员要素市场扭曲水平大于研发资本市场扭曲水平;研发要素市场扭曲对高技术产业创新绩效的影响具有拐点效应;研发要素市场扭曲有利于中西部地区高技术产业发展,对东部地区的高技术产业发展不利.

The classification recognition rate of motor imagery is a key factor to improve the performance of brain–computer interface (BCI). Thus, we propose a feature extraction method based on discrete wavelet transform (DWT), empirical mode decomposition (EMD), and approximate entropy. Firstly, the electroencephalogram (EEG) signal is decomposed into a series of narrow band signals with DWT, then the sub-band signal is decomposed with EMD to get a set of stationary time series, which are called intrinsic mode functions (IMFs). Secondly, the appropriate IMFs for signal reconstruction are selected. Thus, the approximate entropy of the reconstructed signal can be obtained as the corresponding feature vector. Finally, support vector machine (SVM) is used to perform the classification. The proposed method solves the problem of wide frequency band coverage during EMD and further improves the classification accuracy of EEG signal motion imaging.

随着生活水平的提高以及教育体制的改革,大学生旅游群体日益壮大,针对大学生这一细分市场开发旅游产品势在必行.以南京市在校大学生为研究对象,通过问卷调查发现,大学生旅游意愿强烈,单次旅游消费以1001～2000元为主,旅游消费行为较为理性,受家庭经济状况影响较大.针对大学生旅游消费现状,从准确定位需求、多渠道营销和合理定价三个方面为企业开发旅游市场提出建议.