基于场强模型的合肥、马鞍山、芜湖三市融入长三角的现状与对策

文章首先概述了引力模型相关理论,提出经济辐射场强模型,通过模型得出合肥、马鞍山、芜湖融入长三角的客观条件辐射场强和主观条件辐射力;再以长三角15市接受上海经济辐射的辐射阈值为标准,分别总结出属于前三个层次的长三角城市并将其作为安徽三市融入长三角的主导城市进行承接;最后,根据安徽三市各自产业特点给出它们融入长三角的对策,为实现安徽省全面融入长三角经济圈奠定基础。     

关于大量程超声波料位计的算法修正讨论

随着现代科学技术的不断提升,煤矿、铁矿、造纸、稀土等行业的自动化水平取得飞速发展,能否稳定、准确、智能地测量料位决定着这些行业是否能够向现代化、智能化发展。测量料位的方法有很多,其中超声波料位计采用非接触方式,能够有效避免光线、粉尘、烟雾和电磁干扰的影响。研究和设计精度高、稳定性好、性价比高的超声波料位计是充满挑战性和具有现实意义的课题。考虑到超声波的传播速度受温度的影响较大,推导出带有温度补偿的速度修正计算公式,并应用在软件算法中;为了进一步提高测量精度,本文还详细分析了超声波传播的实际路径并给出了计算公式。     

一种嵌入式软件无线电频谱监测系统

为了降低研发成本，提高频谱系统的灵活性和缩短研制周期，提出了一种基于软件无线电的嵌入式频谱监测系统。首先研究了系统硬件平台组成和特点，在此基础上设计了一种灵活的软件定义系统架构；然后考虑到硬件平台自身性能的限制，重点研究了频率偏移校正、频谱扫描策略等关键技术，分别提出了基于GSM信号和温度传感器的频偏校正方法和基于相关性的扫频策略；最后通过具体实验，对系统性能进行验证与评估，结果表明所提出的频偏校正方法能够将绝对平均频偏控制在1.749×10-6以内，所设计的基于相关性的扫频策略对时变信号的频谱监测效果最好。     

相关信噪比对天线组阵相位估计性能的影响

传统天线组阵理论为了简化分析，均假设反正切相位鉴别器是一种最大似然估计器，其估计方差能够达到克拉美-罗下界。然而当相关信噪比在中等值以下时，这一假设条件不再适用。为此，分析了相关信噪比对相位估计性能的影响。针对传统天线组阵合成性能分析方法在描述低相关信噪比条件下相位估计性能方面存在的问题，通过引入修正因子，得到了相位估计方差的理论公式，实现了对低相关信噪比条件下相位估计性能的准确描述。     

Does global liquidity drive commodity prices?

This paper tackles the question of whether a cross-sectional perspective on monetary policy is capable of explaining movements in global commodity prices. In this vein, we contribute to the rich literature on global liquidity in two different ways: on the one hand, to achieve a global series in terms of common monetary policy shocks, we propose a distinction between common and idiosyncratic factors across economies, as proposed by Bai and Ng (2004). Our second innovation stems from the consideration of a Markov-switching vector error correction model when analyzing time-varying short-run dynamics. Having identified the long-run structure which includes a proportional relationship between commodity prices and global liquidity in the first step, our results indeed show that the impact of a global liquidity measure on different commodity prices is significant and varies over time. One regime approximately accounts for times where commodity prices significantly adjust to disequilibria, while the second regime is characterized by either a weak or no commodity price adjustment. The fact that global liquidity also reacts to disequilibria in a specific regime demonstrates the two-way causality between monetary policy and commodity prices.     

冻结造孔防斜保直实践与应用

冻结造孔施工过程中,控制井斜靶域半径问题是冻结造孔的关键点。以陕西麟北煤业开发有限责任公司园子沟煤矿冻结造孔施工为例,本文着重分析冻结造孔施工中靶域半径控制及钻孔防斜保直、测斜、定向技术实践应用。     

Automatic leading indicators versus macroeconometric structural models: A comparison of inflation and GDP growth forecasting

This paper compares the forecast performance of automatic leading indicators (ALIs) and macroeconometric structural models (MESMs) commonly used by non-academic macroeconomists. Inflation and GDP growth form the forecast objects for comparison, using data from China, Indonesia and the Philippines. ALIs are found to outperform MESMs for one-period-ahead forecasts, but this superiority disappears as the forecast horizon increases. It is also found that ALIs involve greater uncertainty in choosing indicators, mixing data frequencies and utilizing unrestricted VARs. Two ways of reducing the uncertainty are explored: (i) give theory priority in choosing indicators, and include theory-based disequilibrium shocks in the indicator sets; and (ii) reduce the VARs by means of the general-to-specific modeling procedure.     

Bartlett correction to the likelihood ratio test for MCAR with two‐step monotone sample

Assuming that two‐step monotone missing data is drawn from a multivariate normal population, this paper derives the Bartlett‐type correction to the likelihood ratio test for missing completely at random (MCAR), which plays an important role in the statistical analysis of incomplete datasets. The advantages of our approach are confirmed in Monte Carlo simulations. Our correction drastically improved the accuracy of the type I error in Little's (1988, Journal of the American Statistical Association, 83 , 1198–1202) test for MCAR and performed well even on moderate sample sizes.     

Technology-based ventures and sustainable development: Cointegrating and causal relationships with a panel data approach

The aim of this article is to provide new empirical evidence on the causality between proxy variables of technology entrepreneurship and proxy variable of sustainable economic performance in a vector error correction model. It covers a sample of 13 countries participated to Global Entrepreneurship Monitor studies under the period 2002–2013. Building on a theoretical background that considers the adoption of new technologies through a dynamic process of creative destruction based on innovation as the most important factor for achieving long-term economic growth, the empirical investigation uses robust econometric techniques that are capable of estimating long-run cointegrating relationships in panel data.

Our results support the idea that total entrepreneurship activity related to the technology sector leads to improve the sustainability of a nation in the long run. More importantly, our paper helps understand the nature of liaison between the creation of innovative and high-technology business and the presence of favorable social and environmental conditions for the well-being of a population.