Consistency of Water Production Function Models of Two Crops

On basis of test information, the research performed analysis on water production function models of two crops, which indicated that water model of crops in whole growth stage and water model of crops indifferent growth stages have consistency as well as differences, providing references for optimization of irrigation water. Meanwhile, the research analyzed the deficiency of optimization on irrigation water for crops just by Jensen model.

Saline Water Irrigation Scheduling Through a Crop-Water-Salinity Production Function and a Soil-Water-Salinity Dynamic Model

Using a crop-water-salinity production function and a soil-water-salinity dynamic model, optimal irrigation scheduling was developed to maximize net return per irrigated area. Plot and field experiments were used to obtain the crop water sensitivity index, the salinity sensitivity index, and other parameters. Using data collected during 35 years to calculate the 10-day mean precipitation and evaporation, the variation in soil salinity concentrations and in the yields of winter wheat and cotton were simulated for 49 irrigation scheduling that were combined from 7 irrigation schemes over 3 irrigation dates and 7 salinity concentrations of saline irrigation water (fresh water and 6 levels of saline water). Comparison of predicted results with irrigation data obtained from a large area of the field showed that the model was valid and reliable. Based on the analysis of the investment cost of the irrigation that employed deep tube wells or shallow tube wells, a saline water irrigation schedule and a corresponding strategy for groundwater development and utilization were proposed. For wheat or cotton, if the salinity concentration was higher than 7.0 g L-1 in groundwater, irrigation was needed with only fresh water; if about 5.0 g L-1, irrigation was required twice with fresh water and once with saline water; and if not higher than 3.0 g L-1, irrigation could be solely with saline water.

基于三阶段DEA模型的安徽省农业生产效率探析

基于安徽省各市2021年农业生产的投入产出数据,构建农业生产效率评价指标体系,运用三阶段DEA模型测度安徽省2021年各市的农业生产效率状况,选取农村居民人均可支配收入、农林水事务支出和城镇化率作为环境变量,重点探讨调整前后安徽省各市的综合技术效率、纯技术效率和规模效率等变化趋势。结果表明:剔除环境因素和随机干扰的影响后,安徽省的综合技术效率和规模效率均有所提升,纯技术效率下降了0.1%,整体的农业生产效率虽然未达到高效水平,但与调整前相比已有所改善,多数城市调整后的纯技术效率水平不高,反映了农业生产缺乏专业的管理模式和先进的技术。从环境因素来看,农村居民人均可支配收入水平提高和增加农林水事务支出对农业生产效率起到显著的正向作用,而城镇化率则成为农业生产效率的不利因素。

基于DEA模型的山东省沿黄流域果业生产效率提升研究

沿黄流域果业高质量发展对落实黄河流域生态保护和高质量发展国家战略,推动果业振兴、乡村振兴意义重大。综述了果业生产效率相关研究,基于实际调研了山东省菏泽、滨州、东营市的果园情况和数据,构建了山东省沿黄流域果品投入产出指标体系,利用DEA模型进行果业生产效率测算,有针对性地提出发展规模经营、调整投入结构比例、强化现代栽培管理、发展智慧化生产等建议,以期推动沿黄流域果业高质量发展。

基于DEA-Malmquist模型的临沂市农业生产效率研究

选取2013—2021年临沂市各县区农业生产要素的投入、产出面板数据,基于投入导向的DEA-BCC模型对临沂市农业生产效率进行了测算与评价,使用Malmquist指数对临沂市农业全要素生产率进行了测算与分解,并从动态变化角度分析了农业生产效率的年际变化趋势。结果表明:临沂市各县区的农业生产效率差异较大、总体水平较低,且多数县区处于规模报酬递增趋势;临沂市农业全要素生产率提升的动力主要源于技术进步,且年均增长率呈上升趋势。鉴于此,提出了优化生产要素投入,提升规模效率;加强农业技术的研发与推广,促进农业技术进步;加大财政支出力度,提高农业生产效率等政策建议。

Model-Driven Derivation of Domain Functional Requirements from Use Cases

Domain analysis is essential to core assets development in software product line engineering. Most existing approaches, however, depend on domain experts’ experience to analyze the commonality and variability of systems in a domain, which remains a manual and intensive process. This paper addresses the issue by proposing a model-driven approach to automating the domain requirements derivation process. The paper focuses on the match between the use cases of existing individual products and the domain functional requirements of a product line. By introducing a set of linguistic description dimensions to differentiate the sub-variations in a use case, the use case template is extended to model variability. To this end, a transformation process is formulated to sustain and deduce the information in use cases, and to match it to domain functional requirements. This paper also presents a prototype which implements the derivation as a model transformation described in a graphical model transformation language MOLA. This approach complements existing domain analysis techniques with less manual operation cost and more efficiency by automating the domain functional requirements development.

我国农产品物流效率及影响因素——基于DEA-Malmquist和Tobit模型

应用DEA-Malmquist指数测算2015—2021年我国30个省市区的农产品物流效率,运用Tobit回归分析研究区农产品物流效率影响因素。实证结果表明:1)从静态来看,观测期内我国农产品物流综合效率较低,技术效率略低,投入要素配置尚未达到合理状态;2)从动态来看,我国农产品物流全要素率增长,技术进步作用较为关键;3)在多维影响因素中,信息化和物流发展程度是提升农产品物流效率的主要因素。因此,文章从政府、市场和行业等角度提出了提高我国农产品物流效率的建议。

基于DEA-Malmquist模型的大豆主产区成本效率测算与评价

大豆作为我国粮食作物中营养价值较高的作物,对于我国居民膳食的结构改善起重要作用。但目前,大豆作物存在依赖进口、自给率较低、生产成本较高等问题。从大豆生产过程中的经济成本角度出发,选取2013—2020年我国大豆主产区的大豆生产成本面板数据,基于投入导向,通过DEA模型和Malmquist指数对大豆生产的成本效率进行测算与指数分解,分析大豆在生产成本投入上存在的问题。研究发现,近8年来,各主产区全要素生产率多数处于边际报酬不变或递增的趋势,但年份增长率呈下降趋势,并且投入与产出要素存在不同程度的冗余现象;全要素生产率下降的主要因素源于技术进步不足。因此,在提升大豆成本效率的对策上可以采用着重提升科技水平、加大科研投入、优化投入要素规模和提高政府财政支持等措施。

Review of Carbon Emissions Trading Production Model and Research on Its Applications in China

With the Kyoto Protocol entering into effect in many countries one after another,carbon trading has come into being and developed quickly.China is the main supplier of carbon emissions rights in the world,but such transactions are still in the stage of Clean Development Mechanism (CDM) projects without its own trading system,which is not conducive for China to win the rights of carbon pricing in the international market.Low-carbon and emissions reduction is the international trend nowadays,and therefore,it is particularly necessary and urgent to investigate the issue of carbon trading in China.In this paper,the authors have reviewed Putty-Clay Vintage,which is a model of production function for carbon trading,revealing the main points,contributions and shortcomings of the model.Combined with China's national conditions,the authors have investigated the application of this model in China's carbon trading from four different angles,including enterprise production optimization,financial market development,national macro-economy,and the allocation of emission quota.This study aims to provide China's enterprises with an analytical framework when participating in carbon trading in the future and it is beneficial for them to make optimal production planning when considering the cost of carbon emissions reduction.

基于DEA-Tobit模型的生猪产业绿色发展效率研究

近年来,生猪产业绿色化取得长足进展。为了解生猪产业绿色发展效率变化情况及相关影响因素,研究首先通过DEA模型对生猪产业绿色发展效率进行测算,研判样本期内生猪产业绿色发展效率变化情况;再利用面板Tobit模型分析生猪产业绿色发展效率的影响因素。结果表明:从时间维度观察,生猪产业绿色发展效率在研究期间展现出波动上升的趋势,而在2019年之后,这一趋势则趋于稳定并持续上升。若从空间角度审视,内蒙古、黑龙江等9个省份在生猪产业绿色发展效率方面的提升最为显著。进一步分析动态效率,我们发现规模效率在推动生猪产业绿色发展效率提升中起到了关键作用。此外,资源禀赋、经济发展水平、环境规制、开放程度、交通通达度和规模化水平等要素,均对生猪产业绿色发展效率产生了显著的正向影响,为其提升提供了强大的驱动力。资源禀赋、经济发展水平、环境规制、开放程度、交通通达度和规模化水平均可显著正向提升生猪产业绿色发展效率。因此,应从释放区域资源禀赋、差异化落实环境规制和推动规模化养殖等方面提高生猪产业绿色发展效率。

On Enforcing Dyadic-type Homogeneous Binary Function Product Constraints in MatBase

Homogeneous binary function products are frequently encountered in the sub-universes modeled by databases,spanning from genealogical trees and sports to education and healthcare,etc.Their properties must be discovered and enforced by the software applications managing such data to guarantee plausibility.The(Elementary)Mathematical Data Model provides 17 types of dyadic-based homogeneous binary function product constraint categories.MatBase,an intelligent data and knowledge base management system prototype,allows database designers to simply declare them by only clicking corresponding checkboxes and automatically generates code for enforcing them.This paper describes the algorithms that MatBase uses for enforcing all 17 types of homogeneous binary function product constraint,which may also be employed by developers without access to MatBase.

基于PCA-DEA模型的福建省生鲜农产品冷链物流效率分析

随着居民可支配收入的提高以及国内生产总值的增长,人们的生活条件与过去相比有了一个质的飞跃。在这样的大背景之下,人们对生鲜农产品的需求不断地增加,不仅需要足量的生鲜农产品,更加考虑生鲜农产品的新鲜度以及安全性,由此期待能够提高冷链物流的效率。文章选取了福建省2012—2021年这10年的冷链物流相关数据,运用PCA模型从众多能够影响冷链物流效率的投入因素中找出主要的影响因素,并用DEA数据包络法算出冷链物流效率,并且对该省的效率进行分析,在此基础上提出相关建议。

基于两阶段Bootstrap-DEA模型的甘薯种植专业合作社生产效率及影响因素研究

采用2021年国家甘薯产业技术体系产业经济固定观察点调查数据,运用两阶段Bootstrap-DEA和单侧截断回归方法衡量甘薯种植专业合作社的甘薯生产效率。结果显示:(1)甘薯种植专业合作社的规模效率比较高,而技术效率和纯技术效率偏低,说明合作社带来的规模效应比较显著,但其在管理水平提升和生产技术改善方面存在较大约束;(2)合作社牵头人个人特征对生产效率有显著正面影响,合作社成员数量、享有政府优惠政策、按交易量返还比率对生产效率有一定促进作用,而重大事务决策主体为理事长对其有抑制作用。根据实证分析结果,提出促进甘薯合作社发展的对策建议。

Application of an Economy-Climate Model to Assess the Impact of Climate Change

An interdisciplinary investigation was conducted to assess the impact of climate change on grain yields using an economy-climate model （C-D-C）. The model was formulated by incorporating climate factors into the classic Cobb-Douglas （C-D） economic production function model. The economic meanings of the model output elasticities are described and elucidated. The C-D-C model was applied to the assessment of the impact of climate change on grain yields in China during the past 20 years, from 1983 through 2002. In the study, the land of China was divided into eight regions, and both the C-D-C and C-D models were applied to each individual region. The results suggest that the C-D-C model is superior to the classic C-D model, indicating the importance of climate factors. Prospective applications of the C-D-C model are discussed.

基于超效率三阶段DEA模型的安徽省智慧农业生产效率分析

智慧农业作为现代农业的重要载体,在促进传统农业生产方式变革、推动农民收入增长、提升农业生产效率以及实现农业高质量发展等方面都具有重要意义。本文采用超效率三阶段DEA模型测算安徽省智慧农业生产效率,并分析其时空特征。结果显示:安徽省智慧农业生产效率水平较为良好,各地市生产效率均值都在0.5以上;2015—2021年安徽省智慧农业生产效率整体均值呈上升趋势,并且由非DEA有效转变为DEA有效;安徽省智慧农业生产效率空间差异较大,整体来看,皖北地区智慧农业生产效率高于皖南地区。基于此,安徽省应建立健全智慧农业生产的投入和产出体系,调整智慧农业生产格局;加强智慧农业平台搭建,注重智慧农业技术创新。

Impact of Education on Productivity:A Model in China

Improving the quality of human resources through edu-cation and training is of great strategic significance.However, few people have done in depth and systematicstudies on the relationship between education and pro-ducttvity in China. This study developed an educationproductivity transform model and empirically tested themodel using data on the most districts of China. The ba-sic notion is that the effect depends both on the capabilityresulted from education, and on the environment inwhich this capability can be exercised, the effect is a re-sult of two factors combined.

Agricultural Production Efficiency of Chongqing Based on DEA

Literatures about agricultural production efficiency are reviewed.Concept of DEA Method,as well as the definition methods of effective DEA and scale efficiency increase are introduced.According to the relevant statistical data in the years 1997-2007 in Chongqing Municipality,efficiency of agricultural economy is calculated from the year 1997 to 2007 by DEA method and the scale efficiency is also analyzed by taking the total output of agriculture,forestry,animal husbandry and fishery industry as the output index.And the input index includes total workforce in agriculture,forestry,animal husbandry and fishery,the total sown area of crops,the total power of agricultural machinery,chemical fertilizer application,the draft animal,and the effective irrigation area.Result shows that Chongqing City became a municipality directly under the central government;its agricultural production efficiency is still low.And the sustainable development capacity of agricultural is weak in Chongqing,and the agricultural resources are not fully used.Based on this,related suggestions are put forward to improve the agricultural production efficiency of Chongqing,such as implementing an appropriate management scale of land,improving the organization degree of peasant households and the rate of industrialization management,enhancing the quality of the rural labor force,strengthening the agricultural science and technology input and extension,perfecting the construction of rural infrastructure,and improving the rate of resource utilization.

Energy Dependence of String Fragmentation Function and Ф Meson Production

The meson productions in Au+Au and/or Pb+Pb collisions at AGS, SPS, RHIC, and LHC energies have been studied systematically with a hadron and string cascade model LUCIAE. After considering the energy dependence of the model parameter α in string fragmentation function and adjusting it to the experimental data of charged multiplicity to a certain extent, the model predictions for meson yield, rapidity, and transverse mass distributions are compatible with the experimental data at AGS, SPS and RHIC energies. A calculation for Pb+Pb collisions at LHC energy is given as well. The obtained fractional variable in string fragmentation function shows a saturation in energy dependence. It is discussed that the saturation of fractional variable in string fragmentation function might be a qualitative representation of the energy dependence of nuclear transparency.

Empirical Analysis of Gross Domestic Product and Coal Import Based on VAR Model

The speed of China’s economic development is gradually accelerating, and the demand for energy is also constantly increasing, especially the demand for coal. In order to reveal whether the coal imports have an impact on China’s economic development, this paper constructs the VAR(6) model by selecting the quarterly data of coal imports (CIV) and gross domestic product (GDP) from 2002 to 2017, performing ADF (Augmented Dickey-Fuller) stationarity test and Johansen cointegration test. It shows that there is a long-term stable equilibrium relationship between coal imports and GDP. Then the impulse response function is used to obtain the relationship between coal imports and GDP. It is found that the impact of coal imports on GDP is greater than the impact of GDP on coal imports.

基于DEA的贵州省生鲜农产品物流效率评价

本文在对DEA效率评价及生鲜农产品物流效率相关研究的基础上,以2012—2021年贵州省生鲜农产品物流数据为样本,运用DEA模型对其进行分析。研究表明:贵州省各年生鲜农产品物流的综合技术效率、技术效率及规模效率有效性呈现不稳定的状态。本文结合物流效率评价分析结果,提出发展贵州省生鲜农产品物流效率的对策,分别为:加大政府扶持力度、培养冷链物流专业人才、加强生鲜农产品物流基础设施建设、发展第三方物流提升其管理水平等。