产业集聚是否促进了低碳发展——来自中国制造业的证据

产业集聚是否促进了低碳发展?基于1990—2010年中国制造业的有关数据构建制造业空间集聚指数(EG),构建产业集聚与碳排放强度的计量经济模型;基于协整理论、误差修正模型和Granger因果关系检验等方法的研究结果表明:产业集聚程度与碳排放强度具有长期稳定的均衡关系,产业集聚程度为碳排放强度的单向格兰杰原因。     

航空通信系统试飞过程中的电磁兼容性评估

电磁兼容性(EMC)是航空电子产品的主要性能,也是实现系统功能的重要保证。试飞试验是 按照预想实现一种思想而提供最终证据的在机载真实环境条件下进行飞行试验,并通过试飞 数据分析结果评估系统效能,所以,EMC预测是航空电子系统试飞评估主要内容之一。论述 了基于电磁拓扑（Electromagnetic Topology）理论分析的航空通信系统EMC评估方法,该 方法已在航空通信系统试飞中被采用。     

A local bicycle helmet ‘law’ in a Swedish municipality – the effects on helmet use

The municipality of Motala in Sweden introduced a local bicycle helmet ‘law’ on May 1, 1996. This is not a legally enacted ordinance, but instead a legislated recommendation backed up by information and education. Formally, the law applies to children (aged 6–12 years), although the intention is to increase helmet use by all cyclists. The objective of the present study was to quantitatively evaluate the impact of the Motala helmet law on observed use of helmets by children and adults. Bicycle helmet use was monitored in Motala (n = 2,458/year) and in control towns (n = 17,818/year) both before and after adoption of the helmet law (1995–1998). Chi-square tests showed that helmet wearing 1995–1998 increased in Motala among all bicyclists (from 6.1% to 10.5%) and adults biking on cycle paths (from 1.8% to 7.6%). Helmet use by school children aged 6–12 increased during the first 6 months after introduction of the law (from 65.0% to 75.7%) but then progressively decreased to the pre-law level. Considering children cycling on cycle paths and for recreation in housing areas, there was a tendency towards increased helmet use during the first post-law year, but this was followed by a reduction to a lower level in 1998 than in 1995. Logistic regression analysis taking into account data from the control towns indicated that the helmet law had a positive effect on children cycling to schools during the first 6 months, and a weak delayed but more long-term positive effect on adult cyclists on cycle paths. There were no positive effects on children in housing areas and on cycle paths. The Motala helmet law probably would have had greater and more lasting effects on helmet use by bicyclists, if certain problems had been avoided during the initiation phase. Moreover, although it did have a positive influence on both school children and adults, it is not legally binding, and hence no penalties can be imposed. Presumably, compulsory legislation would have a more substantial impact on helmet wearing than a non-mandatory helmet ‘law’ such as that introduced in Motala.     

Contract farming and smallholder incentives to produce high quality: experimental evidence from the Vietnamese dairy sector

In emerging markets for high‐value food products in developing countries, processing companies search for efficient ways to source raw material of high quality. One widely embraced approach is contract farming. But relatively little is known about the appropriate design of financial incentives in a small farm context. We use the example of the Vietnamese dairy sector to analyze the effectiveness of existing contracts between a processor and smallholder farmers in terms of incentivizing the production of high quality milk. A framed field experiment is conducted to evaluate the impact of two incentive instruments, a price penalty for low quality and a bonus for consistent high quality milk, on farmers’ investment in quality‐improving inputs. Statistical analysis suggests that the penalty drives farmers into higher input use, resulting in better output quality. The bonus payment generates even higher quality milk. We also find that input choice levels depend on farmers’ socio‐economic characteristics such as wealth, while individual risk preferences seem to be less important. Implications for the design of contracts with smallholders are discussed.     

基于 Granger 检验的能源消费与经济增长区域差异性研究

本文运用1993～2012年29省市的能源消费和经济增长数据,以能源消费弹性系数的变化规律为依据,将我国的能源———经济区划分为：经济发达区、平稳发展H区、平稳发展L区和飞速发展区四大发展区域。针对四大区域,利用Granger检验法对各区域能源消费与经济增长二者之间的关系进行了研究。研究结果表明,经济发达区的能源消费与经济增长不具有长期协整关系,平稳发展H区的能源消费与经济增长具有双向因果关系,平稳发展L区和飞速发展区能源消费与经济增长具有单向因果关系。最后针对以上结论提出了相关建议。     

Evolving United States stock market volatility: The role of conventional and unconventional monetary policies

Despite the econometric advances of the last 30 years, the effects of monetary policy stance during the boom and busts of the stock market are not clearly defined. In this paper, we use a structural heterogeneous vector autoregressive (SHVAR) model with identified structural breaks to analyse the impact of both conventional and unconventional monetary policies on U.S. stock market volatility. We find that contractionary monetary policy enhances stock market volatility, but the importance of monetary policy shocks in explaining volatility evolves across different regimes and is relative to supply shocks (and shocks to volatility itself). In comparison to business cycle fluctuations, monetary policy shocks explain a greater fraction of the variance of stock market volatility at shorter horizons, as in medium to longer horizons. Our basic findings of a positive impact of monetary policy on equity market volatility (being relatively stronger during calmer stock market periods) are also corroborated by analyses conducted at the daily frequency based on an augmented heterogeneous autoregressive model of realised volatility (HAR-RV) and a multivariate k-th order nonparametric causality-in-quantiles framework. Our results have important implications both for investors and policymakers.     

基于Plant Simulation的烟草柔性分拣系统仿真与优化

针对烟草物流配送中心场地限制和分拣效率低下等问题,根据柔性分拣系统的工作原理及流程,运用Plant Simulation仿真软件建立烟草柔性分拣系统模型,设计了条烟自动分拣的虚拟托盘算法。通过仿真分析得到限制其分拣效率的瓶颈工位,利用添加缓存区和增加码垛工位的优化方法对分拣系统进行初步优化,并且从Experiment Manager模块中的单因子多水平试验方法确定了最优缓存区容量。仿真结果表明该优化方法显著提高了分拣效率,使其达到8866.08条/h,是优化前的1.39倍,且缩短了配送时间,能够很好地满足烟草物流配送中心的分拣要求。     

基于Feed4JUnit架构的单元测试技术研究与应用

软件测试技术在软件质量控制过程中一直起着非常重要的作用。JUnit是被广泛应用的Java单元测试框架,主要测试基于java语言编写的程序代码,用于编写和运行可重复的测试。Feed4JUnit是开源的基于JUnit的扩展,通过使用Feed4JUnit提供的注释,用户可以很方便地把测试数据存放在文件或其他数据源。本文分析了应用Feed4JUnit进行单元测试的方法,并通过实际开发示例实现数据与代码分离的测试。     

浙江省区域物流与经济增长的实证研究

基于浙江省1990~2012年统计数据,运用ADL模型及格兰杰因果检验对浙江省区域物流与经济增长的相互关系进行了研究。结果表明:从长期来看,浙江省GDP、全社会货物周转量及港口货物吞吐量三者之间存在着单向的因果关系。港口货物吞吐量是全社会货物周转量增加的格兰杰原因,全社会货物周转量和港口货物吞吐量平均每增长1%,分别带动浙江省GDP增长0.8672%和0.9903%。     

土石坝砾质粘土的击实曲线研究

通过室内击实试验我们可以测定土的最大干密度和最优含水率,以此成为压实度检测的依据,以便控制好填筑土体的压实质量,更好地保障工程质量达到所规定的要求。不同土体,不同的操作方法,击实试验的结果是不同的,本文章结合苗尾水电站料场的土料的特性,通过对比颗粒含量与界限含水率的不同,分析击实曲线的变化规律。