农地发展权流出、资本回流与区域经济增长*——基于重庆市的实证研究

[目的]以重庆市为研究区域,以农地发展权资本化的地票指标为研究对象,从理论和实证层面探讨农地发展权交易与资本要素的城乡互动关系及其对区域经济增长的影响,为进一步优化农地发展权交易政策、促进区域均衡发展提供相关建议。[方法]基于2008—2017年城乡统筹改革试验区重庆市地票指标交易的面板数据,运用要素禀赋理论和差分GMM模型从理论和实证层面分析农地发展权流出区土地与资本要素的互动关系及其对区域经济增长的影响。[结果]基于区域间资源禀赋的差异及要素相对价格的分化,在市场机制作用下,农地发展权指标将以配置效率优化为导向在不同区域间自由流动。[结论]短期内,由于资本约束,流出农地发展权的区域其经济增长会受到抑制;而当农地发展权指标资本化后,流出区获得了较为稀缺的货币资本,农地发展权流出将显著促进地方经济增长;同时,在研究时期内,由于农地发展权市场交易机制的构建,重庆市地方经济增长存在显著的收敛效应,区域间经济发展差距将会逐步缩小。     

A Novel Compact Cat Swarm Optimization Based on Differential Method

ABSTRACT

A compact cat swarm optimization scheme (cCSO) is proposed in this paper, which is designed to solve application domains plagued with limited memory and less-computation power, as a member of cat swarm optimization algorithms (CSO), it composes of two sub-modes, i.e., tracing and seeking modes, so it keeps the same search logic of CSO. On the other hand, cCSO inherits the main feature of compact algorithms, a normal probabilistic model is used to represent the population of solutions instead of processing an actual population, which ensures the cCSO to have the modest memory requirement. The updating vector for the probabilistic model provides a clear moving direction for cats in next step. A cat without historical position and velocity is applied in the algorithm. When the cat is in seeking mode, it employs a differential operator to update the cat’s position, which makes it possible for the cat to have multiple searching directions. Experimental results show that cCSO has pretty performance compared with respect to some population-based testing benchmarks. And it also shows superior performance in convergence rate to some compact optimization algorithms. The case study of gray image segmentation proves that it suits for solving the optimization problem by limited hardware.     

Using paradata to collect better survey data: Evidence from a household survey in Tanzania

Data are a key component in the design, implementation, and evaluation of economic and social policies. Monitoring data quality is an essential part of any serious, large‐scale data collection process. The purpose of this article is to show how paradata should be used before, during, and after data collection to monitor and improve data quality. To do this we use timestamps, global positioning system (GPS) coordinates, and other paradata collected from an 800‐household survey conducted in Tanzania in 2016. We demonstrate how key paradata can be used during each phase of a research project to identify and prevent issues in the data and the methods used to collect it. Our results corroborate the importance of collecting and analyzing paradata to monitor fieldwork and ensuring data quality for micro data collection in developing countries. Based on these findings we also make recommendations as to how researchers can make better use of paradata in the future to manage and improve data quality. We argue for an expansion in the understanding and use of varied paradata among researchers, and a greater focus on its use for improving data quality.     

基于不同城市化发展阶段的山西省城镇建设用地适度集约利用研究

研究目的:针对城市化进程中的土地低效利用以及过度集约问题,探讨不同城市化发展阶段的土地集约利用状况及适度集约利用状态。研究方法:采用匹配度模型、曲线估计模型和多目标规划模型,对山西省的土地集约利用进行分区优化。研究结果:(1)1999—2012年山西省土地集约利用与城市化水平之间的匹配趋势逐渐由失调、磨合向协调转变,但不同地区之间的匹配水平差距却在逐渐扩大;(2)2018年山西省城市化水平处于低于30%、30%～70%和高于70%时,以单位城镇建设用地固定资产投资额为表征的土地适度集约利用值分别为249.93万元/km~2、367.57万元/km~2和692.72万元/km~2,两项指标叠加全省可划分为平稳发展区、重点挖潜区和优化拓展区,并提出了不同地区差别化的建设用地管控政策。研究结论:不同城市化发展阶段的土地适度集约利用研究能为制定区域差别化政策提供参考,以促进该地区的土地集约利用水平达到适度状态。     

非线性延迟系统Runge-Kutta方法的稳定性探讨

针对时间依赖型的非线性多变延迟系统,采用变步长的Runge-Kutta方法求解,证明了匹配一定插值方法的代数稳定的Runge-Kutta方法是VR稳定的。     

MULTIDIMENSIONAL DYNAMIC RISK MEASURE VIA CONDITIONAL g‐EXPECTATION

This paper deals with multidimensional dynamic risk measures induced by conditional g‐expectations. A notion of multidimensional g‐expectation is proposed to provide a multidimensional version of nonlinear expectations. By a technical result on explicit expressions for the comparison theorem, uniqueness theorem, and viability on a rectangle of solutions to multidimensional backward stochastic differential equations, some necessary and sufficient conditions are given for the constancy, monotonicity, positivity, and translatability properties of multidimensional conditional g‐expectations and multidimensional dynamic risk measures; we prove that a multidimensional dynamic g‐risk measure is nonincreasingly convex if and only if the generator g satisfies a quasi‐monotone increasingly convex condition. A general dual representation is given for the multidimensional dynamic convex g‐risk measure in which the penalty term is expressed more precisely. It is shown that model uncertainty leads to the convexity of risk measures. As to applications, we show how this multidimensional approach can be applied to measure the insolvency risk of a firm with interacting subsidiaries; optimal risk sharing for ‐tolerant g‐risk measures, and risk contribution for coherent g‐risk measures are investigated. Insurance g‐risk measure and other ways to induce g‐risk measures are also studied at the end of the paper.     

基于DSP的高动态接收机载波捕获跟踪技术

介绍了高动态GPS接收机的码捕获与载波跟踪的原理,设计了一种基于高速数字信号处理(DSP)技术的PLL FLL环混合全数字高动态载波跟踪技术方案,同时给出了一种在连续高动态下载波跟踪算法即基于交叠离散傅里叶变换的频率跟踪算法(ODAFC),并对此算法进行了仿真验证.仿真结果证明了该算法的正确性.     

PROPERTIES OF OPTION PRICES IN MODELS WITH JUMPS

We study convexity and monotonicity properties of option prices in a model with jumps using the fact that these prices satisfy certain parabolic integro–differential equations. Conditions are provided under which preservation of convexity holds, i.e., under which the value, calculated under a chosen martingale measure, of an option with a convex contract function is convex as a function of the underlying stock price. The preservation of convexity is then used to derive monotonicity properties of the option value with respect to the different parameters of the model, such as the volatility, the jump size, and the jump intensity.     

油田特种作业车辆燃油管理系统的研究

为解决油田特种作业车辆和台上设备在生产运行中个别操作者盗卖燃油的问题,我们利用高精度燃油测量装置,对特种作业车辆台上设备的燃油消耗进行准确计量,并通过车载GPS终端通讯信道实时上传到监控管理系统进行展现和统计分析,解决了特种车辆燃油消耗考核不能落实到单车的难题,经济效益和社会效益明显,有很好的推广应用前景。     

社会统筹养老金供给的两难困境与政策选择

在中国养老保险制度建立与完善过程中,其主要矛盾仍然是如何筹资和如何给付的问题。社会统筹主要通过提高缴费率和扩大覆盖面两条途径来增加基金供给,而现行制度却面临着养老金供给的两难困境。一是提高缴费率增加了基金收入,但不利于经济增长与扩大覆盖面;二是不同群体实行差别费率有利于扩大覆盖面,但加剧了养老金收支的失衡。经数理模型与实证分析,社会统筹缴费率应该保持适度水平,同时应该对不同群体实行差别费率的政策进行调整,以建立养老保障的长效机制。