地区间投入产出模型分析

地区间投入产出模型是投入产出分析领域中非常重要又非常复杂的内容,它是研究地区间经济联系和物流关系的工具,它对研究如何发挥不同地区经济优势,确定生产力合理布局,优化资源配置,特别是对当前研究西部大开发与东部和中部之关系具有重要的意义.论文对世界上已有的地区间投入产出模型进行综述,简要介绍3个较为经典的模型,说明地区间投入产出模型的发展轨迹,分析各自特点、适用情况及其差别,希望对我国的地区间投入产出分析模型发展有所帮助.

西部地区间投入产出模型及应用研究

本文通过编制西部地区间投入产出表(包括资源占用部分),分析西部地区经济的协调发展,研究西部资源因素对经济发展的影响。文章着重介绍了列系数模型的结构和在西部经济分析中的应用;阐述了资源占用参数的计算方法及其在研究资源的制约作用中的应用。

PROGRESS OF GREY SYSTEM MODELS

The progress of grey system models is reviewed, and the general grey numbers, the grey sequence op- erators and several most commonly used grey system models are introduced, such as the absolute degree of grey incidence model, the grey cluster model based on endpoint triangular whitenization functions, the grey cluster model based on center-point triangular whitenization functions, the grey prediction model of the model GM （ 1,1）, and the weighted multi-attribute grey target decision model.

Direction of arrival estimation of coherent sources based on arbitrary plane arrays

A method of direction of arrival (DOA) estimation of coherent sources is proposed, which is based on arbitrary plane arrays. After constructing the mathematical model of coherent sources, virtual array transformation and MUSIC algorithm are used to realize the azimuth estimation of coherent sources, which improved the DOA estimation performance greatly. According to the computer simulation, its validity is confirmed.

Single Server Queueing Models and Birth-Death Process

A transition diagram is used to describe the behavior of systems. Birth-death equations were derived from transition diagram depicting the state of the birth-death processes. Queue models and characteristics of queue models are also derivable from birth-death processes. These queue models consist of mathematical formulas and relationships that can be used to determine the operating characteristics （performance measures） for a waiting line. Schematic and transition diagrams of different single server queue models were shown. Relationships between birth-death processes, waiting lines （queues） and transition diagrams were given. While M/M/I/K queue model states was limited by K customers and had （K＋I） states, M/M/1/1 queue model had only two states. M/G/1/∝/∝ and M/M/1/∝/∝ shared similar characteristics. Many ideal queuing situations employ M/M/1 queueing model.

TESTING SERIAL CORRELATION IN SEMIPARAMETRIC VARYING COEFFICIENT PARTIALLY LINEAR ERRORS-IN-VARIABLES MODEL

The authors propose a V_(N,p) test statistic for testing finite-order serial correlation in asemiparametric varying coefficient partially linear errors-in-variables model.The test statistic is shownto have asymptotic normal distribution under the null hypothesis of no serial correlation.Some MonteCarlo experiments are conducted to examine the finite sample performance of the proposed V_(N,p) teststatistic.Simulation results confirm that the proposed test performs satisfactorily in estimated sizeand power.

Modified series model for cross-plane thermal conductivity of short-period Si/Ge superlattices

Superlattices have great application potentials in thermo-electric materials and solid laser techniques.Their complicated heat transport mechanisms due to size effects,multi-interfaces and mini-band are very important issues for the prediction of thermal conductivity.In this paper,the short-period Si/Ge superlattices are investigated by a modified series model based on the Debye-Callaway description.The Lambert Law is used to describe the phonon emission within hemisphere space.In addition,the phonon interface transmission coefficients obtained from the phonon wave packet simulation are incorporated into boundary condition of the model,which removes the fitting parameters in the model.Better agreement with experiment is obtained.The effects of temperature,wavelength-dependent phonon transmission,superlattice periods,as well as the thickness of Ge layer are considered in this paper.

A method for detection and quantification of meshing characteristics of harmonic drive gears using computer vision

A lack of accurate description of the meshing characteristics and the corresponding frictional mechanism of the harmonic drive gear has limited progress toward modeling the hysteresis stiffness. This paper presents a method for detection and quantification of the meshing characteristics of the harmonic drive gear based on computer vision. First, an experimental set-up that integrates a high speed camera system with a lighting system is developed, and the image processing is adopted to extract and polish the tooth profiles of the meshed teeth pairs in each acquired video sequence. Next, a physical-mathematical model is established to determine the relative positions of the selected tooth pair in the process of the gear engagement, and the combined standard uncertainty is utilized to evaluate the accuracy of the calculated kinematics parameters. Last, the kinematics analysis of the gear engagement under the ultra-low speed condition is performed with our method and previous method, and the influence of the input rotational speed on the results is examined. The results validate the effectiveness of our method, and indicate that the conventional method is not available in the future friction analysis. It is also shown that the engaging-in phase is approximately a uniform motion process, the engaging-out phase is a variable motion process, and these characteristics remain unchanged with the variation of the input rotational speed. Our method affords the ability to understand the frictional mechanism on the meshed contact surfaces of the harmonic drive gear, and also allows for the dynamic monitoring of the meshing properties.