教育对经济发展贡献的计量模型与方法研究

本文首先对国内外计量教育对经济发展贡献的经典文献进行了梳理,接着根据教育促进经济发展的作用机制,提出了用投入产出法计算教育对经济发展直接贡献的方法,然后本文设定了一个新的模型,专门用来验证教育形成的人力资本与物质资本、技术进步之间的互补关系并确认人力资本是否具有外溢性,最后本文设定了一个计量教育对经济发展间接贡献模型并提出了相应的计量方法。

计量经济学模型方法的实践研究

随着计量经济学理论研究的不断深入,计量经济学模型方法应用实践研究也逐渐成为学术界探讨的主要内容。从许多相关研究资料都可发现,计量经济学应用领域处于不断扩展发展趋势,如管理学领域、社会学领域中都有所涉及。本文将从计量经济学模型检验与发现、归纳与演绎、证伪与证实等角度,对计量经学模型方法进行研究。

关于计量经济学模型方法的思考

关于讨论计量经济学模型方法的哲学问题的思考,目前有以下几个结论,较为完整的广义上的计量经济学模型方法不仅仅是通常认为的能检验、不能发现,而是完全能做出科学研究的过程.需要经济学模型检验过程的归纳和计量经济学模型设置过程的演绎二者相结合,才能构成辩证的和较为完整的计量经济学模型方法的认识论.

基于农户层面的退耕还林工程评价方法研究综述

梳理基于农户层面的退耕还林工程评价文献,系统地阐述了描述性统计分析方法,计量模型方法(逻辑回归分析、倍差法、收支函数模型、层次分析法、结构方程模型、博奕论)和参与式调查方法等退耕还林工程评价方法。展望未来研究趋势:深入进行量化研究,继续扩展研究方法。

再谈计量经济学模型方法论研究

本文对计量经济学模型方法论研究的论文进行了综述、补充和总结,包括关于计量经济学模型方法科学性的研究、关于计量经济学模型经济学基础的研究、关于计量经济学模型统计学基础的研究、关于计量经济学模型设定理论的研究和关于计量经济学课程内容体系的研究。

我国财政支出对经济增长的乘数效应分析

财政政策作为调控手段,在宏观经济发展中起着十分重要的作用。基于1985-2006年我国财政支出和GDP的时序数据,对国家财政支出对经济增长影响的路径、强度、乘数效应等进行了研究;同时利用2006年我国各地区相应的有关截面数据,通过空间计量建模,对各地区的财政支出与经济增长的现时乘数效应进行了分析。研究结论表明,现今我国财政支出对经济增长的乘数效应为4.26;它们之间存在倒U型关系。各级政府应逐步增加财政支出力度,并注重合理优化财政支出结构,以便有利于各地区和全国经济的进一步增长。

Verification and Improvement of the Ability of CFSv2 to Predict the Antarctic Oscillation in Boreal Spring

The boreal spring Antarctic Oscillation(AAO)has a significant impact on the spring and summer climate in China.This study evaluates the capability of the NCEP's Climate Forecast System,version 2(CFSv2),in predicting the boreal spring AAO for the period 1983-2015.The results indicate that CFSv2 has poor skill in predicting the spring AAO,failing to predict the zonally symmetric spatial pattern of the AAO,with an insignificant correlation of 0.02 between the predicted and observed AAO Index(AAOI).Considering the interannual increment approach can amplify the prediction signals,we firstly establish a dynamical-statistical model to improve the interannual increment of the AAOI(DY AAOI),with two predictors of CFSv2-forecasted concurrent spring sea surface temperatures and observed preceding autumn sea ice.This dynamical-statistical model demonstrates good capability in predicting DY AAOI,with a significant correlation coeffcient of 0.58 between the observation and prediction during 1983-2015 in the two-year-out cross-validation.Then,we obtain an improved AAOI by adding the improved DY AAOI to the preceding observed AAOI.The improved AAOI shows a significant correlation coeffcient of 0.45 with the observed AAOI during 1983-2015.Moreover,the unrealistic atmospheric response to March-April-May sea ice in CFSv2 may be the possible cause for the failure of CFSv2 to predict the AAO.This study gives new clues regarding AAO prediction and short-term climate prediction.

Variable Relation Parametric Model on Graphics Modelon for Collaboration Design

A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method for different graphic modelon based on variable constraint. At the same time, with the aim of engineering application in the collaboration design, the autonmous constraint in modelon and relative constraint between two modelons are given. Finally, with the tool of variable and relation dbase, the solving method of variable relating and variable-driven among different graphic modelon in a part, and double-acting variable relating parametric method among different parts for collaboration are given.

Development of a mass model in estimating weight-wise particle size distribution using digital image processing

Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumu- lative mass percent. But digital image processing generated size distribution of particles, while being fast and accurate, is often expressed in terms of area function or number of particles. In this paper, a mass model is developed which converts the image obtained size distribution to mass-wise distribution, mak- ing it readily comparable to mechanical sieving data. The concept of weight/particle ratio is introduced for mass reconstruction from 2D images of particle aggregates. Using this mass model, the effects of several particle shape parameters （such as major axis, minor axis, and equivalent diameter） on sieve-size of the particles is studied. It is shown that the sieve-size of a particle strongly depend upon the shape param- eters, 91% of its variation being explained by major axis, minor axis, bounding box length and equivalent diameter. Furthermore, minor axis gives an overall accurate estimate of particle sieve-size, error in mean size （D-50） being just 0.4%. However, sieve-size of smaller particles （〈20 ram） strongly depends upon the length of the smaller arm of the bounding box enclosing them and sieve-sizes of larger particles （〉20 mm） are highly correlated to their equivalent diameters. Multiple linear regression analysis has been used to generate overall mass-wise particle size distribution, considering the influences of all these shape parameters on particle sieve-size. Multiple linear regression generated overall mass-wise particle size distribution shows a strong correlation with sieve generated data. The adjusted R-square value of the regression analysis is found to be 99 percent （w.r,t cumulative frequency）. The method proposed in this paper provides a time-efficient way of producing accurate （up to 99%） mass-wise PSD using digital image processing and it can be used effectively to renlace the mechanical sieving.

Using Energy Conditions to Distinguish Brane Models and Study Brane Matter

Current universe （assumed here to be normal matter on the brahe） is pressureless from observations. In this case the energy condition is po ≥ 0 and po =O. By using this condition, brahe models can be distinguished. Then, assuming arbitrary component of matter in DGP model, we use four known energy conditions to study the matter on the brahe. If there is nonnormal matter or energy （for example dark energy with w 〈-1/3） on the brane, the universe is accelerated.

Space range estimate for battery-powered vertical take-off and landing aircraft

A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem models including required thrust, required power and battery discharge models are presented. The problem to be optimized is formulated, and then case study simulation is conducted using the established method for quantitative analysis. Simulation results show that the space range of battery-powered VTOL aircraft in a vertical plane is an oblate curve, which appears horizontally long but vertically short, and the peak point is not located on the vertical climb path. The method and results are confirmed by parameter analysis and validations.

Related factors and regional differences in energy consumption in China

This article used the Cluster analysis of statistical method to separate China＇s 30 provinces and municipalities into three categories according to their energy consumption discrepancies and characteristics from 1985 to 2007. The categories were high, moderate and low energy consumption areas and they had significant differences in energy consumption. Based on this classification, the authors analyzed the influencing factors of energy consumption in the three areas by means of panel data econometric model. The results showed that the influencing factors were obviously different. In order to support national goal of energy conservation and emission reduction, the energy measures and policies should be distinctly taken.

Adiabatic correction for the esterification of acetic anhydride by methanol via accurate kinetics

In the field of adiabatic correction for complex reactions,a simple one-stage kinetic model was used to estimate the real reaction kinetics.However,this assumption simplified the real process,inevitably generated inaccurate or even unsafe results.Therefore,it was necessary to find a new correction method for complex reactions.In this work,esterification of acetic anhydride by methanol was chosen as an object reaction of study.The reaction was studied under different conditions by Reaction Calorimeter(RC1).Then,Thermal Safety Software(TSS)was used to establish the kinetic model and estimate the parameters,where,activation energies for three stages were67.09,81.02,73.77 kJ?mol^(-1)respectively,and corresponding frequency factors in logarithmic form were 16.05,19.59,15.72 s^(-1).In addition,two adiabatic tests were performed by Vent Sizing Package2(VSP2).For accurate correction of VSP2 tests,a new correction method based on Enhanced Fisher method was proposed.Combined with kinetics,adiabatic correction of esterification reaction was achieved.Through this research,accurate kinetic parameters for a three-step kinetic model of the esterification reaction were acquired.Furthermore,the correlation coefficients between simulated curves and corrected curves were 0.976 and 0.968,which proved the accuracy of proposed new adiabatic correction method.Based on this new method,conservative corrected results were able to be acquired and be applied in safety assessment.

Calculation on model of weakening hydrogen bond of thick oil of petroleum

The process of use catalyst or functional material that contains iron ion to weaken -O-H-O- hydrogen bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge. covalent bond order, total energy and the average distance of Fe-O. is studied with density function theory and discrete variational method （DFT-DVM）, one of the first principle methods. With the decrease of the distance of Fe-O. the charge of Fe ion increases, the charge of hydrogen ion decreases, and hydrogen bond is weakened. There are obvious and more stable effects to use the catalyst that contains multiple metal ions or increase the catalyst amount in weakening hydrogen bond of the thick oil. This theoretic work is helpful to exploit and process the thick oil of petroleum and maybe overcome the crisis of petroleum energy is approaching to us.

Model-Based Integrated Methods for Quantitative Estimation of Soil Salinity from Hyperspectral Remote Sensing Data:A Case Study of Selected South African Soils

Soil salinization is a land degradation process that leads to reduced agricultural yields. This study investigated the method that can best predict electrical conductivity (EC) in dry soils using individual bands, a normalized difference salinity index (NDSI), partial least squares regression (PLSR), and bagging PLSR. Soil spectral reflectance of dried, ground, and sieved soil samples containing varying amounts of EC was measured using an ASD FieldSpec spectrometer in a darkroom. Predictive models were computed using a training dataset. An independent validation dataset was used to validate the models. The results showed that good predictions could be made based on bagging PLSR using first derivative reflectance (validation R2 = 0.85), PLSR using untransformed reflectance (validation R2 = 0.70), NDSI (validation R2 = 0.65), and the untransformed individual band at 2257 nm (validation R2 = 0.60) predictive models. These suggested the potential of mapping soil salinity using airborne and/or satellite hyperspectral data during dry seasons.

Progress on quantitative assessment of the impacts of climate change and human activities on cropland change

It is important to study the contributions of climate change and human activities to cropland changes in the fields of both climate change and land use change. Relationships between cropland changes and driving forces were qualitatively studied in most of the previous researches. However, the quantitative assessments of the contributions of climate change and human activities to cropland changes are needed to be explored for a better understanding of the dynamics of land use changes. We systematically reviewed the methods of identifying the contributions of climate change and human activities to cropland changes at quantitative aspects, including model analysis, mathematical statistical method, framework analysis, index assessment and difference comparison. Progress of the previous researches on quantitative evaluation of the contributions was introduced. Then we discussed four defects in the assessment of the contributions of climate change and human activities. For example, the methods were lack of comprehensiveness, and the data need to be more accurate and abundant. In addition, the scale was single and the explanations were biased. Moreover, we concluded a clue about quantitative approach to assess the contributions from synthetically aspect to specific driving forces. Finally, the solutions of the future researches on data, scale and explanation were proposed.