The Operation Mechanism of Agricultural Products Supply Chain and Profit Allocation Model in the Context of Asymmetric Information

The research performed analysis on causes of asymmetric information of agricultural product supply chain and made conclusion on operation mechanism and characteristics of supply chain based on asymmetric information. Finally, the research detailed profit sharing of agricultural product supply chain in the context of asymmetric information and proposed suggestions, providing references of pricing and profit sharing of supply chains of agricultural products.

Tea Production Response to Seasonal Rainfall Variability: Evidence from Rwanda

Tea is a very important cash crop in Rwanda, as it provides crucial income and employment for farmers in poor rural areas. From 2017 to 2020, this study was intended to determine the impact of seasonal rainfall on tea output in Rwanda while still considering temperature, plot size (land), and fertiliser for tea plantations in three of Rwanda’s western, southern, and northern provinces, western province with “Gisovu” and “Nyabihu”, southern with “Kitabi”, and northern with “Mulindi” tea company. The study tested the level of statistical significance of all considered variables in different formulation of panel data models to assess individual behaviour of independent variables that would affect tea production. According to this study, a positive change in rainfall of 1 mm will increase tea production by 0.215 percentage points of tons of fresh leaves. Rainfall is a statistically significant variable among all variables with a positive impact on tea output Qitin Rwanda’s Western, Southern, and Northern provinces. Rainfall availability favourably affects tea output and supports our claim. Therefore, there is a need for collaboration efforts towards developing sustainable adaptation and mitigation options against climate change, targeting tea farming and the government to ensure that tea policy reforms are targeted towards raising the competitiveness of Rwandan tea at local and global market.

Generation of input spectrum for electrolysis stack degradation test applied to wind power PEM hydrogen production

Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.

Structure of continuous matrix product operator for transverse field Ising model:An analytic and numerical study

We study the structure of the continuous matrix product operator(cMPO)^([1]) for the transverse field Ising model(TFIM).We prove TFIM’s cMPO is solvable and has the form T=e^(-1/2H_(F)).H_(F) is a non-local free fermionic Hamiltonian on a ring with circumferenceβ,whose ground state is gapped and non-degenerate even at the critical point.The full spectrum of H_(F) is determined analytically.At the critical point,our results verify the state–operator-correspondence^([2]) in the conformal field theory(CFT).We also design a numerical algorithm based on Bloch state ansatz to calculate the lowlying excited states of general(Hermitian)cMPO.Our numerical calculations coincide with the analytic results of TFIM.In the end,we give a short discussion about the entanglement entropy of cMPO’s ground state.

Optimal Aggregate Production Plans via a Constrained LQG Model

In this paper, a single product, multi-period, aggregate production planning problem is formulated as a linear-quadratic Gaussian (LQG) optimal control model with chance constraints on state and control variables. Such formulation is based on a classical production planning model developed in 1960 by Holt, Modigliani, Muth and Simon, and known, since then, as the HMMS model [1]. The proposed LQG model extends the HMMS model, taking into account both chance-constraints on the decision variables and data generating process, based on ARMA model, to represent the fluctuation of demand. Using the certainty-equivalence principle, the constrained LQG model can be transformed into an equivalent, but deterministic model, which is called here as Mean Value Problem (MVP). This problem preserves the main properties of the original model such as convexity and some statistical moments. Besides, it is easier to be implemented and solved numerically than its stochastic version. In addition, two very simple suboptimal procedures from stochastic control theory are briefly discussed. Finally, an illustrative example is introduced to show how the extended HMMS model can be used to develop plans and to generate production scenarios.

Assessment of Relationship of Some Causal Factors Associated with Productivity of Longwall Mining Using Structured Equation Modeling

Enhancement of productivity optimization is steadily gaining the priority in mining companies especially in the underground coal mining industry which faces a daunting task to balance marginal profit generation with a comparatively high cost of production, volatile market price and rapid grade variation. This paper is aimed to analyze some of the causal factors both technical and site specific which are directly or indirectly impacting the productivity of the longwall coal mining system such as downtime of equipment system in longwall panel, overloading of conveyors and bin, preventive maintenance, gas management practices and injury severity rate. Structured Equation Modelling (SEM) was used to study the causal relationships between the above-mentioned factors and mine productivity. The equipment considered for analysis included shearer, armored face conveyor, crusher, bridge stage loader, chock supports, main gate drive, gate conveyor, hydraulic pumps and crusher. SEM was applied to relate the correlations existing among these causal variables in order to assess their direct or indirect impact on mining productivity. Based on the data extracted over a period of 10 months which included the extraction of 2 longwall panels, the study revealed a significant negative causal relationship between injury severity rate (p < 0.01) and equipment downtime (p = 0.001), with mine productivity. However, preventive maintenance delay time, gas management delay time and conveyor overloading delay time were found to have an insignificant direct influence on mine productivity but indirectly modify it through a significant mediator relationship with equipment downtime. This information would assist mine management to take proper preventive measures.

A Multi-layer Information Integration Platform for Chemical Process Operation Systems

In the process industry, automation and process control systems are widely implemented, information integration is however far away from satisfactory. It remains a hard job for senior managers to make decisions based on the plant-wide real-time integrated information. This paper proposes a multi-layer information integration platform. In the data integration level, the standard for the exchange of product (STEP) and the extensible markup language (XML) are used to unify these data of the chemical process. In the model integration level, the models are integrated by using the neutral model repository and CAPE-OPEN. In the integration of process task, the common object request broker architecture (CORBA) is used as the communication mediator. The XML is taken as the data standard. A uniform information platform is thus constructed and realized. The proposed information integration platform is satisfactorily implemented to solve the Tennessee Eastman (TE) problem.

THE COMPREHENSION,SOME PROBLEMS AND SUGGES-TIONS TO SYMBOLIC VECTOR METHOD AND SOME DEFENSES FOR GIBBS'SYMBOL

The comprehension of Prof. Tai's symbolic vector method in vector analysis presented, some problems are found and some suggestions are provided to solve them. Some defenses for Gibbs' symbol have been made as well. Key words: symbolic vector(? ?; operator; vector product model

A Literature Review of the“Burning Money”Behavior of Internet Products

This article mainly studies the current status of the operation of the“burning money model”of Internet products,expounds and analyzes the disadvantages of this operating model,studies the practical effects brought by the“burning money model”,and explores the development direction of future Internet products.Domestic scholars have done a lot of research on the development of Internet products in the future and have achieved certain results.This article aims to discuss the development model of China’s Internet products,summarize the current“burning money”behavior in the operation process of Internet products,and combine the development situation of China’s Internet in the new era to make suggestions for the future development of Internet products.

面向波动可再生能源的质子交换膜电制氢系统最优压强运行

为提升质子交换膜电制氢系统在波动可再生能源输入下的制氢效率,提出面向最大效率的质子交换膜电制氢系统最优压强运行模式。介绍质子交换膜电制氢系统,提出基于压强控制的协调运行原理;对质子交换膜电制氢系统的压强特性和功率特性进行建模,从而建立面向最大效率的压强优化模型。在波动电流输入算例下检验最优压强运行模式的制氢效果,结果表明,相较于恒定压强模式,最优压强运行模式下的质子交换膜电制氢系统平均制氢能耗得到有效降低,系统性能得到明显提升。

中国茶叶生产格局变迁及其影响因素研究

基于1985—2021年中国茶叶生产面板数据,采用GIS空间分析、多尺度地理加权回归模型探究中国茶叶生产格局的时空演变特征及影响因素。结果表明:(1)1985—2021年,中国茶叶生产规模不断扩大,生产重心持续“西移”,空间集聚存在显著正向规模效应,江南、华南和西南茶区聚集特征以“高高”型和“低高”型聚集为主,江北茶区未出现集聚特征,空间极化现象突出。(2)不同时期影响中国茶叶生产格局变迁的主导因素存在显著差异。1995年以有效灌溉面积和化肥投入量为主,2010年降水量、日照时数、受灾面积的影响程度逐步凸显,2020年后交通运输水平成为显著驱动因素,但是有效灌溉始终是影响茶叶生产格局变迁的主要驱动力。

保障生态产品价值实现的生态积分体系研究

现有生态积分实践缺乏对应理论指导,存在分散性与自发性特征,未能充分实现其应有价值。基于生态积分现实基础与理论渊源的分析,从基础理论支撑体系、实践操作模型体系、基本制度规范体系视角对构建生态积分体系进行了研究,结果表明:生态积分体系是一个由基础理论支撑体系、实践操作模型体系和基本制度规范体系三者构成的有机体。其中,生态积分基础理论支撑体系是由本源理论、前置理论、运行理论与预测理论有机形成的内循环平面理论体系;生态积分实践操作模型体系是由生态积分规则、生态积分平台、生态积分兑换结合形成的三向联动体系;生态积分基本制度规范体系是由原则要求与基本维度两个方面构筑而成的制度规范体系。

耕地经营规模对农户水稻生产生态效率的影响——以常德市为例

提高水稻生产生态效率是协同实现保障粮食产量稳增长与减少粮食生产环境损耗双目标的关键路径,耕地作为农业生产活动最基本的生产资料之一,探索耕地经营规模对农户水稻生产生态效率的影响对促进农业适度规模化经营和耕地可持续利用具有重要意义。本文基于粮食生产微观主体——农户的视角,从理论上揭示耕地经营规模对农户水稻生产生态效率的影响,并利用常德市416份农户问卷调查数据,运用随机前沿分析法构建效率测算模型和影响模型进行实证检验。研究表明:农户耕地规模化水平和水稻生产生态效率均有待提升,样本农户中较小规模农户数量最多,占总样本的94.95%,较小规模农户仍是农业生产的主力;农户水稻生产生态效率均值为0.830,还存在0.170的提升空间。耕地经营规模对农户水稻生产生态效率有显著影响,二者并非简单线性关系而是呈“倒U型”关系,且拐点所在区间为1.2~1.4 hm2;农户水稻生产生态效率还受到户主受教育程度、抚养比、农业收入占比的显著正向影响和户主年龄的显著负向影响。因此,应在尊重较小规模农户将长期存在这一现实的基础上,进一步推进耕地适度规模经营并培育新型农户,以促进水稻生产生态效率提高。

A Nonlinear Grey Bernoulli Model with Conformable Fractional-Order Accumulation and Its Application to the Gross Regional Product in the Cheng-Yu Area

This study considers a nonlinear grey Bernoulli forecasting model with conformable fractionalorder accumulation,abbreviated as CFNGBM(1,1,λ),to study the gross regional product in the ChengYu area.The new model contains three nonlinear parameters,the power exponentγ,the conformable fractional-orderαand the background valueλ,which increase the adjustability and flexibility of the CFNGBM(1,1,λ)model.Nonlinear parameters are determined by the moth flame optimization algorithm,which minimizes the mean absolute prediction percentage error.The CFNGBM(1,1,λ)model is applied to the gross regional product of 16 cities in the Cheng-Yu area,which are Chongqing,Chengdu,Mianyang,Leshan,Zigong,Deyang,Meishan,Luzhou,Suining,Neijiang,Nanchong,Guang’an,Yibin,Ya’an,Dazhou and Ziyang.With data from 2013 to 2021,several grey models are established and results show that the new model has higher accuracy in most cases.

基于机器学习的成品油管道运行工况识别

为改善成品油管道系统生产运行监测过程中不能自动识别部分运行状态,以及异常工况识别准确率较低的问题,应用智能工况识别方法,构建具有实时监测能力的成品油管道运行工况识别模型。首先,采用逻辑规则判别方法,并根据成品油管道系统中的事件日志补充数据标签;其次,按照工况的起止时间对数据进行分段,并采用滑动窗口的方式提取不同工况的子序列及其特征;然后构建成品油管道运行工况识别模型,并与随机森林(RF)、自适应提升(AdaBoost)、支持向量机(SVM)、时间序列森林(TSF)、随机区间谱系森林(RISF)和序列学习器(SEQL)等6种机器学习分类模型进行对比,分析其识别效果;最后,以某真实成品油管道为例,进行模型验证。结果表明:TSF模型对阀门开关、阀门内漏、清管和甩泵4种工况的识别精确度最高,且更适合短期内运行工况的识别;而AdaBoost模型的识别精确度在95%的置信区间内所含真实值的概率更高。

农业生产者绿色生产要素投入行为的收入效应

以有机肥和生物农药两类绿色投入品为例,运用内生转换回归模型,实证分析农业生产者绿色生产要素投入行为的收入效应,并运用无条件分位数回归进行异质性分析。研究表明:(1)绿色生产要素投入行为受到内外部因素的影响,不同绿色生产要素的投入行为影响因素有所差异;(2)不同绿色生产要素投入决策条件下农业收入的影响因素有较大差异,新型农业经营类型能够显著提高农业收入;(3)绿色生产要素投入行为具有正向收入效应;(4)有机肥投入随着农业收入的提升,影响程度有逐渐递减趋势,生物农药投入对农业收入的影响程度呈现“倒U”型特征,不同主体类型和地理区域对不同农业收入水平的影响程度存在显著差异。

数字化背景下大宗贸易供应链金融运营模式和风险研究

数字化技术的快速发展,为大宗贸易供应链金融运营模式注入新活力。本文首先对大宗产品供应链金融模式进行分析,阐述应收账款模式、保兑仓模式、融通仓模式及其应用要点。其次,本文分析数字化背景下大宗贸易供应链金融运营模式面临的风险,并提出从产业园着手优化金融运营环境、从企业自身着手规避风险、加强内部管理、创新数字化供应链金融运营模式四点建议,旨在有效应对供应链金融风险,提高大宗产品贸易产业稳定性和竞争力。

短视频运营对农户特色农产品种植收入的影响

依据山东省和河北省836份果品和药材种植户样本数据,采用内生转换回归模型验证了短视频运营对农户特色农产品种植收入的影响。研究发现:(1)影响农户从事短视频运营的因素主要有受访者年龄、教育年限、是否专业种植、种植规模、是否参加合作组织、作物品种、村里是否接通有线网络和是否会使用视频剪辑软件等。(2)短视频运营对农户特色农产品种植收入的作用存在一定的规模效应,粉丝数达到5万以上对农户特色农产品种植收入才能发挥促进作用,随着粉丝数的增加促进作用更加强烈。(3)短视频运营主要通过增加特色农产品销售数量和提升特色农产品销售价格,进而增加农户种植收入。因此应鼓励特色农产品种植户利用短视频、直播等新型农村电商模式,提升农村互联网普及率和提升特色农产品质量。

产品服务系统视角下建筑能源管理系统的设计介入路径 与策略研究

在双碳目标与建筑运行走向电气化智慧化的背景下,推广和应用能源管理系统已成为一种实现节能降耗、降本增效的有效途径。现有建筑能源管理系统研究多以节能技术创新为主,缺乏以用户为中心、兼顾用户舒适度等价值的视角,同时也面临场景差异化应用的挑战。本研究针对能源管理系统这种典型的B端设计问题,借助设计学科的产品服务系统视角研究面向B/C端应用层、采集感知层的设计介入路径,据此提出涉及劝导式设计、服务体验流程和系统创新等设计介入策略。通过典型能源管理系统案例分析验证上述策略,并探讨其相关设计方法,以提升能源管理系统的用户体验和节能目标。

基于SGS模型的茶盘造型设计研究

为进一步拓展产品设计路径,基于管理学中的SGS(门径管理系统,Stage-Gate-System的简称)模型开发产品设计流程,面向用户需求展开SGS模型在产品设计中的应用。以茶盘造型的概念设计为例,结合SGS模型的产品开发方法,优化设计程序,从而解决茶具设计的适用性、美观性及安全性等问题,最终,通过导入SGS模型,提高了茶具设计的用户评价度,为同类产品的造型设计提供参考。