Analysis of the Influence Factors of Grain Supply-Demand Gap in China

Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates the correlation degree between the main grain varieties’ supply and demand gap and its influence factors. The results show that sown area and unit yield have the greatest impact on wheat supply and demand gap;per capita disposable income and unit yield have the greatest impact on corn supply and demand gap;per capita disposable income and agricultural mechanization level have the greatest impact on the supply and demand gap of soybean and rice. From the analysis results, we can obtain the difference between the factors affecting the grain supply and demand gap, and provide a certain theoretical basis and new ideas for the balance of grain supply and demand in China.

Spatiotemporal evolution and influencing factors of urban resilience in the Yellow River Basin,China

The Yellow River Basin of China is a key region that contains myriad interactions between human activities and natural environment.Industrialization and urbanization promote social-economic development,but they also have generated a series of environmental and ecological issues in this basin.Previous researches have evaluated urban resilience at the national,regional,urban agglomeration,city,and prefecture levels,but not at the watershed level.To address this research gap and elevate the Yellow River Basin’s urban resilience level,we constructed an urban resilience evaluation index system from five dimensions:industrial resilience,social resilience,environmental resilience,technological resilience,and organizational resilience.The entropy weight method was used to comprehensively evaluate urban resilience in the Yellow River Basin.The exploratory spatial data analysis method was employed to study the spatiotemporal differences in urban resilience in the Yellow River Basin in 2010,2015,and 2020.Furthermore,the grey correlation analysis method was utilized to explore the influencing factors of these differences.The results of this study are as follows:(1)the overall level of urban resilience in the Yellow River Basin was relatively low but showed an increasing trend during 2010–2015,and significant spatial distribution differences were observed,with a higher resilience level in the eastern region and a low-medium resilience level in the western region;(2)the differences in urban resilience were noticeable,with industrial resilience and social resilience being relatively highly developed,whereas organizational resilience and environmental resilience were relatively weak;and(3)the correlation ranking of resilience influencing factors was as follows:science and technology level>administrative power>openness>market forces.This research can provide a basis for improving the resilience level of cities in the Yellow River Basin and contribute to the high-quality development of the region.

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.

基于熵权法的含间隙和柔性的机构定量分析方法及应用

含间隙机构运动过程中呈现出非线性,为了更好的模拟含间隙机构实际工况,对局部构件做柔性化处理,在建立间隙机构动力学模型的基础上,利用ADAMS二次开发功能,通过Fortran语言自主编写接触力的求解子程序,加载到ADAMS函数求解库中,实现接触模式实时判别和接触力的求解,分析考虑间隙和局部构件柔性对机构的运动特性影响规律。采用Lyapunov指数验证其运动非线性,并在此基础上提出一种基于熵权法的非线性定量分析新方法,通过MATLAB编写熵权法程序并对仿真结果进行定量分析,评估间隙和构件柔性对机构非线性的影响程度,并将该方法应用于2-RR&2-PR并联机构运动特性研究。结果表明:在任何条件下,动平台X方向加速度熵权值最大,说明对非线性影响权重最高,通过分析不同因素对机构非线性影响程度的趋势,使得对机构非线性程度的描述更为准确,为未来含间隙机构非线性定量分析提供了理论参考。

基于灰熵并行分析优化算法的多目标流水车间调度

在供应链环境下构建一个多目标Flow Shop调度优化模型,采用灰熵并行分析(GEPA)法优化该多目标模型。在表征序列间相似程度的灰关联分析法基础上引入信息熵理论建立GEPA法,推导出的灰熵并行关联度衡量多目标Pareto解与理想解的相似程度,并将其作为适应度值引导算法进化,避免多目标优化问题中直接对目标权重赋值。在此基础上建立基于灰熵并行分析的遗传算法。实验结果表明,该算法可有效解决供应链环境下高维多目标Flow Shop调度问题,在多目标最优解、性能评价指标等方面均优于基于随机权重的遗传算法。

灰熵并行分析引导PSO求解多目标优化问题

提出采用灰熵并行分析法引导粒子群算法求解多目标优化问题。灰熵并行分析法综合灰色关联分析法与信息熵的特点,对数据序列计算灰关联系数,同时并行地对数据序列计算信息熵及熵值权重,将灰关联系数与熵值权重结合求得灰熵并行关联度。通过粒子群算法对优化问题的多个目标构建与粒子数相同数量的目标值序列,计算每个序列的灰熵并行关联度值,利用该值作为算法适应度值的分配策略引导粒子进化。以10个典型作业车间调度问题为例进行实验,结果与差分进化算法及遗传算法进行比较,表明灰熵并行分析法可以有效引导各算法进化,使算法在收敛性和分布均匀性方面表现良好,且粒子群算法的优化结果要好于其他两种算法的结果。

Measuring author influence in scientific collaboration networks

Purpose:The purpose of this paper is to measure author influence in scientific collaboration networks by considering the combined effects of multiple indexes.In the meanwhile,we intend to explore a method to avoid assigning subjective weights.Design/methodology/approach:We applied four centrality measures(degree centrality,betweenness centrality,closeness centrality and eigenvector centrality)and authors’published papers to the scientific collaboration network.The grey relational analysis(GRA)method based on information entropy was used to measure an author’s impact in the collaboration network.The weight of each evaluation index was determined based on information entropy.The ACM SIGKDD collaboration network was selected as an example to demonstrate the practicality and effectiveness of our method.Findings:Author influence was not always positively correlated with evaluation indexes such as degree centrality and betweenness centrality.This implies that combined effects of multiple indexes should be considered in author impact analysis.The introduction of the GRA method based on information entropy can reduce the interference of human factors in the evaluation process.Research limitations:We only analyzed author influence from the perspective of scientific collaboration,but the impact of citation on author influence was ignored.Practical implications:The proposed method can be also applied to detect influential authors in bibliographic co-citation network,author co-citation network,bibliographic coupling network or author coupling network.It would help facilitate scientific collaboration and enhance scholarly communication.Originality/value:This paper proposes an analytical method of evaluating author influence in scientific collaboration networks,in which combined effects of multiple indexes are considered and the interference of human factors is reduced in the evaluation process.