秦巴山区非农就业增长的时空格局与影响因素

作为全国脱贫攻坚的重要战场,秦巴山区在全国连片特困地区中极具代表性。在解决相对贫困问题的新阶段,从县域尺度入手,研究精准扶贫战略实施以来秦巴山区非农就业增长的时空格局,并运用空间计量模型探究非农就业增长的影响因素。研究表明:(1)秦巴山区非农就业的空间分布极不均衡。精准扶贫战略实施以来,片区总体就业增长明显快于全国平均水平,但县区间增长趋势差异较大,豫陕鄂交界区域为就业增量的热点区。(2)秦巴山区县域间存在较强的空间依赖关系,邻近县的非农就业增长对本县非农就业增长产生正向溢出效应。(3)初始就业规模、经济增长、社会发展、地理与区位因素共同影响秦巴山区的非农就业增长。初始非农就业规模抑制非农就业增长,地方政府财政支出、医疗卫生水平、到城市的可达性以及平坦的地形条件显著促进非农就业增长。最后,从促进贫困地区非农就业增长角度提出了相应政策建议。

中国连片特困地区非农就业增长的时空特征与驱动因素

中国的贫困治理已从消除绝对贫困转向解决相对贫困的新阶段。增加贫困地区的非农就业机会,保障贫困人口充分有效就业是解决相对贫困问题,促进贫困地区转型发展的根本举措。基于2013—2017年全国14个连片特困地区县域数据,采用空间计量模型方法,解析精准扶贫战略实施以来贫困地区非农就业的空间增长趋势及其驱动因素,并区分了不同人口规模条件下非农就业增长机制的差异性。结果表明:①中国连片特困地区非农就业在空间上表现出较强的非均衡性;②连片特困地区非农就业的增长趋势快于全国平均水平,存在明显的空间分异,并呈现出收敛趋势;③连片特困地区县域间非农就业增长存在较强的空间依赖性,地方性因素和地理结构因素共同影响了连片特困地区的非农就业增长。初始就业水平对非农就业增长具有抑制作用,而地区经济总量、金融资本可获得性、产业结构、基础教育水平、邻近省会或特大城市的市场区位条件、平坦湿润的地理环境等因素显著促进了就业增长;④不同规模县域非农就业增长的决定因素存在显著差异。研究可以为促进贫困地区非农就业增长,推动新时期贫困治理与地区转型发展提供科学参考。

Delay performance analysis and access strategy design for a multichannel cognitive radio network

For a hierarchical cognitive radio network(CRN),the secondary users(SUs) may access the licensed spectrum opportunistically,whenever it is not occupied by the primary users(PUs).An important issue for this kind of CRN is the achievable qualityof-service(QoS) performance,such as traffic transmission delay,which is critical to the SUs' traffic experience.In this paper,we focus on the delay performance analysis of the SU system and the design of the corresponding optimal access strategy for the case of SUs sharing multiple licensed channels.In our analysis,the transmission of PU and SU traffic is modeled as M/G/1 queues.By merging the PU and SU traffic,we propose the model of a priority virtual queue on the licensed channels.Based on this model,we obtain the expected system delay expression for SU traffic through M/G/1 preemptive repeat priority queuing analysis.For the case of multiple licensed channel access,the access strategy is further investigated with respect to the expected system delay for SU traffic.By minimizing the expected transmission delay,the optimal access strategy is modeled as a nonlinear programming problem,which can be resolved by means of the classic Genetic Algorithm(GA).Numerical results validate our analysis and design of an optimal access strategy.Meanwhile,by considering the time taken by the GA approach,we can also adopt the inverse proportional access strategy to obtain near-optimal results in practice.

Spatial heterogeneity of the economic growth pattern and influencing factors in formerly destitute areas of China

Accelerating economic growth in formerly destitute areas and narrowing the economic gap with other regions are essential tasks for poverty alleviation in China after 2020.In this study,the spatio-temporal characteristics of economic growth in 14 formerly destitute areas of China were identified.Moreover,the spatial heterogeneity of various influencing factors was analyzed using a geographically weighted regression model.The results were as follows:(1)The economic level of the formerly destitute areas was low,but their economies grew rapidly after 2011,with annual per capita GDP growth of 10.54%until 2018,higher than the national average of 9.14%.Western and southern counties grew faster economically than central and northern counties.(2)The impact of various factors on the economic growth of counties exhibited clear spatial heterogeneity.The influences of secondary industry growth and level of financial development on economic growth were mainly positive,whereas the effects of initial economic level and market location were mainly negative.(3)Six economic growth driving modes were identified for the 14 contiguous destitute areas,among which the secondary industry-driven mode was the most common.The study can serve as a scientific reference for differentiating regional policies.