The nonlinear time-series analysis method, based on the recurrence plot theory, has received great attention from researchers and has been successfully used in multiple fields. However, traditional recurrence plots that use Heaviside step functions to determine the recursive behavior of a point in the phase space have two problems: (1) Heaviside step functions produce a rigid boundary, resulting in information loss; and (2) the selection of the critical distance, ε, is crucial; if the selection is inappropriate, it will result in a low-dimensional dynamics error, and as of now, there exists no unified method for selecting this parameter. With regard to the problems described above, the novelty of this article lies in the following: (1) when determining the state-phase point recursiveness, a Gaussian function is used to replace the Heaviside function, thereby solving the rigidity and binary value problems of the recursive analysis results caused by the Heaviside step function; and (2) texture analysis is performed on a recurrence plot, new ways of studying complex system dynamics features are proposed, and a system of complex system dynamic-like measurement methods is built.
This paper selects China’s A-share listed companies from 2012 to 2021 as the research sample and explores the impact of digital transformation on corporate green technology innovation and the moderating role of corporate competitive position in this relationship. The research findings are as follows: Digital transformation plays a significant role in promoting corporate green technology innovation. The improvement of corporate competitive position weakens the promoting effect of digital transformation on corporate green technology innovation. The moderating effect of the corporate competition position is more pronounced in the enterprises of the eastern and western regions, as well as in the listed companies in the manufacturing industry. The promoting effect of digital transformation on utility model patent innovation is dramatically attenuated when the corporate competitive position is strengthened. However, the weakening effect on invention patent innovation is not statistically significant.
Automatic generation of test cases using heuristic methods is a hot research topic nowadays. Although its advantages are obvious, it is slightly insufficient in the selection of optimal individuals. Aiming at the existing problems in the evaluation and selection of the optimal individual, this paper proposes a test case evaluation algorithm based on the comprehensive analysis of the characteristics of layer proximity and branch distance function, which is a joint structure of “layer proximity and branch distance function”. The basic idea of this algorithm is that when selecting pilot individuals in the evolutionary process, we first select the individuals with high proximity between the actual execution path and the target path, and then select the individuals with the smallest branching distances among these individuals, so as to obtain the individuals with the optimal piloting ability. Experiments show that the proposed algorithm can quickly find the optimal test cases, especially for the test case generation of multi-layer nested programs.
传统的宏观生产研究存在两大问题,一是普遍采用地区(省际)视角,不能准确反映宏观生产的技术结构,二是基于总量生产函数框架无法单独考察价格因素对生产的影响.文章在利润函数的基础上,重新构建宏观生产分析框架,利用Hotelling引理和欧拉定理,推导出宏观有约束的利润函数,从行业视角估计了宏观生产的利润前沿,并采用Farrell-Debreu径向度量法测度各个行业的技术效率.结果表明:劳动价格、资本价格和劳动投入数量对利润富有弹性,其值为正且依次递减;资本投入数量对利润接近单位弹性,但其值为负,这说明我国单位资本产出率在逐年降低.从行业来看,房地产业、批发零售业等行业技术效率较低,制造业、服务业等行业技术效率较高,经济发展战略中应予以充分重视.
现行的老龄化社会标准是该地区65岁及以上的老年人口占该地区总人口的比重(老年人口比)达到或超过7%.这个标准将65岁及以上的人口不加区别地定义为老年人口,且老年人口比达到或超过7%则被视为进入老龄化社会.然而,人口老化的过程是渐进的,老年人的年龄界限也不应该泾渭分明,此外,不同年龄的老年人之间存在着较大的差异,老年人口比并不能测量人口"老"到什么程度.为此,文章应用模糊数学的理论与方法,引入了老龄隶属度的概念,以区别对待不同年龄的老年人,并定义了人口老龄化深度,从而对人口老龄化测量方法进行了改进.
