Farmers of Jin county want fewer children

The economic reform practiced in the vast rural areas in China gives a great impetus to the vigorous development of rural economy and the the rapid improvement of living standard. Meanwhile, reform pounds at the traditional childbearing ideas. The striking change in the childbearing attitudes of the farmers of the Jin County is a good example. As the farmers of the country are getting well-off when the commodity economy develops rapidly with the rural economic reforms, their childbearing attitudes change. Profound changes have taken place in their mode of production and their life style. The young couples of the county begin to seek small families instead of traditional big ones. They are convinced that under the new situation of reforms, the farmers of an old generation are in no way competent as the head of the family to guide production and therefore want to build their own small families by freeing themselves from the binds of the traditional patriarchal system. The increase in the cost of bringing up children and the economic loss resulting from the absence from work for looking after children constitute another reason to prefer a small family. The son is no more the only economic guarantee for the aged. As a result of the rapid development of the rural economy, a retirement system has been established among the farmers of the Jin county. "It is unreliable to expect that the son will support his aged parents. Now it is better to earn more money and the collective can be depended upon by the aged."     

自由现金流量假说检验:审计收费视角

本研究在控制相关变量下,采用非金融上市公司面板数据,应用混合回归和固定效应回归实证检验自由现金流量和审计收费之间的关系,从审计收费角度检验自由现金流量假说。本研究提供的经验数据表明,自由现金流量和审计收费显著正相关,验证了自由现金流量假说。     

教育培训:林业人力资源开发的重要途径

我国林业正处在重大转折和变化的历史时期。实施新世纪林业跨越式发展战略的关键是要开发人力资源 ,而人力资源开发重要而有效的途径是开展林业教育培训。笔者认为林业教育培训需要在内容、方法、手段及机制上进行全面创新     

抗日战争与贵州近代化

贵州是西南地区一个十分落后的省份,社会发展各方面都相当滞后。抗日战争时期,贵州近代化的进程大大加快,在政治、经济、文化教育、交通邮电各方面都有了一定的发展,而且呈现出自身特点。     

数据包络分析方法的灵敏度分析

本文对数据包络分析方法的有效决策单元作了灵敏度分析。文中首先提出一种只考虑乎一投入量变化时的灵敏度分析方法,然后在此基础上研究几个报入量同时变化时的灵敏度分析。进而扩展到产出量变化投入产出量同时变化时的灵敏度分析,最后用数例进行了说明。     

股利政策的股东财富效应:来自中国股市的经验证据

国内现有文献关于上市公司股利政策的研究,主要集中在股利政策的信号传递理论、代理成本理论和影响因素三个方面,对上市公司通过股利分配实现股东高回报率的股东财富效应研究较少,而国外从税收政策变化和税负差异的角度研究股利政策财富效应并不适合中国的情况。为此,本文基于我国上市公司股权分置的特殊治理结构,以2003-2004年所有分配股利的上市公司为样本,实证检验了我国上市公司股利政策的股东财富效应。研究表明,分配现金股利使非流通股股东实现高回报率,流通股股东获得股票股利的较高短期收益率。     

油套管回收车辆路径问题及基于清除小生境差分演化求解算法研究

在现实的油田生产作业中,为了避免由于物资短缺造成油井工作无法继续等问题的发生,仓库往往会配送比计划需求量多的油管和套管（简称油套管）,未使用的油套管若不能有效回收,会造成极大的资源浪费。但是,若回收油套管发生的成本高于油套管本身的价值,油套管回收工作也变得徒劳。基于此,本文建立考虑油套管回收价值的车辆路径问题模型,并设计基于清除小生镜技术的差分演化算法,求解得到合理的油套管回收方案。然后以中石化华北分公司鄂尔多斯盆地南部油田的油套管回收问题为例,求解得到包括17条回收路径的94口油井的油套管回收方案,其中总运输费用为3.72万元,远低于待回收油套管的价值15.03万元,实现了资源的有效回收。最后对模型进行灵敏度分析以验证模型的鲁棒性。本文的求解结果不仅对油田行业具有节约资源、降低成本的现实意义,也拓展了逆向物流的理论研究。     

Minimizing the total cost of barrier coverage in a linear domain

Barrier coverage, as one of the most important applications of wireless sensor network (WSNs), is to provide coverage for the boundary of a target region. We study the barrier coverage problem by using a set of n sensors with adjustable coverage radii deployed along a line interval or circle. Our goal is to determine a range assignment \(\mathbf {R}=({r_{1}},{r_{2}}, \ldots , {r_{n}})\) of sensors such that the line interval or circle is fully covered and its total cost \(C(\mathbf {R})=\sum _{i=1}^n {r_{i}}^\alpha \) is minimized. For the line interval case, we formulate the barrier coverage problem of line-based offsets deployment, and present two approximation algorithms to solve it. One is an approximation algorithm of ratio 4 / 3 runs in \(O(n^{2})\) time, while the other is a fully polynomial time approximation scheme (FPTAS) of computational complexity \(O(\frac{n^{2}}{\epsilon })\). For the circle case, we optimally solve it when \(\alpha = 1\) and present a \(2(\frac{\pi }{2})^\alpha \)-approximation algorithm when \(\alpha > 1\). Besides, we propose an integer linear programming (ILP) to minimize the total cost of the barrier coverage problem such that each point of the line interval is covered by at least k sensors.     

财政分权体制对劳动力转移影响的实证分析

基于政府支出内生经济增长理论,探讨地级市政府财政自主程度对于服务行业分行业劳动力流动的影响,将行业劳动力变更细分为跨地区和跨行业两类指标,结合2004年至2011年中国城市统计年鉴构建的面板数据,在区分面板数据类型基础上分别采用固定效应模型或随机效应模型研究财政分权体制下这两类指标的变化。研究结果表明,在控制一系列影响因素后,地方财权的扩张只对交通、仓储及邮电、房地产和租赁商务以及服务行业劳动力流入产生正向影响,而批发零售、住宿餐饮、金融和信息行业在地方财权扩张时就业空间受到一定的挤压,导致本地劳动力流出。在跨行业的劳动力流动问题中,受地方财权扩张正向影响的行业为房地产、金融和租赁商务,其他行业则会由于地方政府财税自主权的提升造成就业萎缩;此外,地方政府财权自主程度提升会加剧地区及行业间劳动力的流动。     

中国风险企业内生核心竞争力构建及其实证研究

风险企业核心竞争力的培养和提升问题,是促进中国风险企业健康发展必须解决的一个现实问题。本文通过对风险企业特征的界定,选取41个中国成功风险企业企业家访谈录作为样本。首先采用文本信息挖掘方法,提炼出风险企业内生核心竞争力因子,从一个崭新的角度来研究风险企业核心竞争力,并对每个因子给出具体内涵解释;然后用聚类分析方法,将中国成功风险企业分成四大类,分别给出每一类企业内生核心关键因子构成;最后通过构建BP神经网络模型帮助相关企业合理定位,辅助其建立适合企业发展的内生核心因子,提升企业市场竞争力。