A Note on an Economic Lot-sizing Problem with Perishable Inventory and Economies of Scale Costs:Approximation Solutions and Worst Case Analysis

This paper presents an economic lot-sizing problem with perishable inventory and general economies of scale cost functions. For the case with backlogging allowed, a mathematical model is formulated, and several properties of the optimal solutions are explored. With the help of these optimality properties, a polynomial time approximation algorithm is developed by a new method. The new method adopts a shift technique to obtain a feasible solution of subproblem and takes the optimal solution of the subproblem as an approximation solution of our problem. The worst case performance for the approximation algorithm is proven to be （4√2 ＋ 5）/7. Finally, an instance illustrates that the bound is tight.

（Dis）Economies of Scale in Business Software Systems Development and Enhancement Projects

In the software engineering literature, it is commonly believed that economies of scale do not occur in case of software Development and Enhancement Projects （D＆EP）. Their per-unit cost does not decrease but increase with the growth of such projects product size. Thus this is diseconomies of scale that occur in them. The significance of this phenomenon results from the fact that it is commonly considered to be one of the fundamental objective causes of their low effectiveness. This is of particular significance with regard to Business Software Systems （BSS） D＆EP characterized by exceptionally low effectiveness comparing to other software D＆EP. Thus the paper aims at answering the following two questions： （1） Do economies of scale really not occur in BSS D＆EP？ （2） If economies of scale may occur in BSS D＆EP, what factors are then promoting them？ These issues classify into economics problems of software engineering research and practice.

Scale and scope economies in small household rice farming in Vietnam

The Vietnamese agricultural sector has experienced a dramatic structural change based on increased specialization in rice cultivation.However,small-scale rice-farmers have continued to grow multiple crops,especially in less developed provinces.While the literature advocates crop diversification for reasons of both economic and ecological sustainability,there lacks empirical evidence as to whether crop diversification brings efficiency and productivity gains to small farms.The present study is the first applications of the input-oriented stochastic distance function approach in estimating scale and scope economies using data of multi-crop farming households in Vietnam.We find strong evidence of product-specific economies of scale.Scope economies are also present for rice,vegetable,and other annual crop production.This suggests that crop diversification enhances efficiency and productivity.However,there still exists significant technical inefficiency in crop production,indicating opportunities to expand farm output at the existing level of inputs and technologies.More specifically,our empirical results indicate that it is desirable to expand vegetable and other annual crop production in mountainous areas while rice cultivation can be further expanded in delta and coastal regions.

China＇s Agricultural Modernization and Economies of Scale： Barriers and Solutions

This paper identifies three stages in China's agricultural development with reference to macroeconomic development and international experience.While the first two stages focused on ensuring food security and raising farmer's income,the current stage must give priority to modernizing agricultural production.The lack of progress in this area is due to the following reasons:diminishing return to capital as a result of small and scattered farming operation which has compromised agricultural competitiveness;agriculture is overdependent on subsidy and protection under the conventional wisdom of the uniqueness of agriculture.This paper attempts to reveal the barriers to China s agricultural modernization and proposes recommendations on reforming the land and household registration systems to increase the economies of scale and productivity.

Data Scale, Data Scope and Platform Enterprise Performance: Insights from Digital Platform M&As

Data is a key asset for digital platforms,and mergers and acquisitions(M&As)are an important way for platform enterprises to acquire it.The types of data obtained from intra-industry and cross-sector M&As differ,as does the extent to which they interact within or between platforms.The impact of such data on corporate market performance is an important question to consider when selecting strategies for digital platform M&As.Based on our research on advertising-driven platforms,we developed a two-stage Hotelling game model for comparing the market performance effects of intra-industry M&As and cross-sector M&As for digital platforms.We carried out an empirical test using relevant data from advertising-driven digital platforms between 2009 and 2021,as well as a case study on Baidu’s M&A activities.Our research discovered that intra-industry M&As driven by“data economies of scale”and cross-sector M&As driven by“data economies of scope”are both beneficial to the market performance of platform enterprises.Intra-industry M&As have a more significant positive effect on the market performance of platform enterprises because the same types of data are easier to integrate and develop the“network effect of data scale”.From a data factor perspective,this paper reveals the inherent economic logic by which different types of M&As influence the market performance of digital platforms,as well as policymaking recommendations for all digital platforms to select M&A strategies based on data scale,data scope,and the network effect of data.

The Research of Change Trend of Our Government's Public Expenditure Scale

It is obvious that the change trend of our government expenditure scale declined constantly .The expenditure proportion of science, education, culture and hygiene increased fast, reflected the situation that the finance of our country was transformed into “public finance” from “building type finance” gradually.The expenditure proportion of the local is higher than central authorities. This is disadvantageous for our country’s economy development and society stability.

The Scale Benefit Analysis of Sugar Clusters in Resource-rich Area of Southweatern Guangxi——A Case of Chongzuo City

Based on the scope economic theory of "resource curse" and industrial clusters,the scale of sugar cluster is calculated by the output of sugarcane and sugar while the scale benefit of sugar cluster is measured by the productivity(rate of sugar production),sales output ratio,industrial output value as well as profit margin.Positive analysis of the scale merit of sugar clusters in resource-rich area of southwestern Guangxi is conducted according to related statistics of Chongzuo City.And the primary problems of sugar clusters are pointed out.The profit created by sugar for the sugar industry in Chongzuo City has already been near capacity.The sugar industry is big but not strong.With much governmental interfernce,there is no effective connections and inadequte competitive forces among subjects of the clusters.The extention of industrial chain is limited.Therefore,measures for developing sugar clusters in resource-rich area of southwestern Guangxi are proposed.Industrial structure is to be adjusted to improve the sugarcane cultivation techniques.The industrial chain should be extended to increase the economic benefits of sugar industry.Industrial support is to be strengthened and capital output for sicence and technology increased.Price regualtion fund of grain sugar is to be established with coordination with the superior region.The transformation from savings to investment should be quickened to evade "resource curse".

Data envelopment analysis for scale elasticity measurement in the stochastic case:with an application to Indian banking

In the nonparametric data envelopment analysis literature,scale elasticity is evaluated in two alternative ways:using either the technical efficiency model or the cost efficiency model.This evaluation becomes problematic in several situations,for example(a)when input proportions change in the long run,(b)when inputs are heterogeneous,and(c)when firms face ex-ante price uncertainty in making their production decisions.To address these situations,a scale elasticity evaluation was performed using a value-based cost efficiency model.However,this alternative value-based scale elasticity evaluation is sensitive to the uncertainty and variability underlying input and output data.Therefore,in this study,we introduce a stochastic cost-efficiency model based on chance-constrained programming to develop a value-based measure of the scale elasticity of firms facing data uncertainty.An illustrative empirical application to the Indian banking industry comprising 71 banks for eight years(1998–2005)was made to compare inferences about their efficiency and scale properties.The key findings are as follows:First,both the deterministic model and our proposed stochastic model yield distinctly different results concerning the efficiency and scale elasticity scores at various tolerance levels of chance constraints.However,both models yield the same results at a tolerance level of 0.5,implying that the deterministic model is a special case of the stochastic model in that it reveals the same efficiency and returns to scale characterizations of banks.Second,the stochastic model generates higher efficiency scores for inefficient banks than its deterministic counterpart.Third,public banks exhibit higher efficiency than private and foreign banks.Finally,public and old private banks mostly exhibit either decreasing or constant returns to scale,whereas foreign and new private banks experience either increasing or decreasing returns to scale.Although the application of our proposed stochastic model is illustrative,it can be potentially applied to all firms in the information and distribution-intensive industry with high fixed costs,which have ample potential for reaping scale and scope benefits.

Techno-Economic Assessment of Non-Revenue Water: A Case Study at AER, GWCL

This study utilizes multiple regression analysis and the technique for computing economies of scale to evaluate the dynamics of NRW in the AER of GWCL. Data on monthly total production, billed consumption, total revenue, total production cost and the volume of NRW spanning the period January 2015 to June 2019, was obtained from the headquarters of AER and used for the analysis. The study showed that NRW averaged 59.3% for the period under consideration, which far exceeds the 25% threshold set by the World Bank for developing economies. It was also established that a fairly inelastic relationship exists between NRW and total revenue. Results further show that resources are not optimally used in the AER as proof of diseconomies of scale was observed.

Rational scale of urban rail transit network based on system dynamics

Urban rail transit(URT) has been playing an important role in urban sustainable development with its advantages of high speed,large capacity,high efficiency and low pollution.Estimating URT network scale is the key to ensure the scientificity and feasibility of its construction.The existing studies on rational scale of URT network have not dealt with the interaction of supply and demand.This paper describes the establishment of a system dynamics model of rational URT network scale determination,considering the interaction between URT construction and city social economic development as well as the dynamic equilibrium of capital supply and traffic demand,and the verification of the model validity by applying it to the case of Wuhan City's URT construction.

数字经济、创业与中等收入群体规模

利用马克思资本循环理论、蒂蒙斯创业理论阐释数字经济扩大中等收入群体规模的理论逻辑,并利用2012—2021年中国31个省份的面板数据检验了数字经济对中等收入群体规模的影响。研究发现:数字经济能显著扩大中等收入群体规模。机制研究表明:数字经济能通过促进创业而扩大中等收入群体规模。具体而言,数字经济有助于促进创业融资和优化创业企业的要素配置,从而有助于扩大中等收入群体规模。进一步研究发现:良好的营商环境能强化数字经济对创业的促进作用,从而能强化数字经济对中等收入群体规模的扩大作用。异质性检验结果表明:组织型创业与自我雇佣型创业都能使数字经济更好地发挥其对中等收入群体规模的扩大作用;在数字经济的支持下,无论是在制造业中创业,还是在服务业中创业,均能显著扩大中等收入群体规模。

Risk and Economic Development in the Provision of Public Infrastructure

A public water and sewer utility is created to develop safe, reliable and financially self-supporting potable water and sanitary sewage systems which will meet the water and sewerage needs of the areas served by the utility;to ensure that existing and future utility facilities are constructed, operated and managed at the least possible cost to the users without outside subsidies;and to develop a system that is compatible with the area’s future growth. To gain efficiencies in operation, these new facilities must be developed in accordance with the latest technical and professional standards to protect the health, safety, and welfare of the citizens served now or in the future. Hence a utility must construct new pipelines, pump stations and other infrastructure, whether that infrastructure is for growth, to improve existing service, or to replace infrastructure that has reached the end of its useful, economic, and/or physical life. In established or stable communities, the replacement of existing infrastructure, where it is no longer economical to operate, is deteriorated to a point where replacement is more cost effective than repairs due to wear, neglect or environmental conditions, or where the infrastructure no longer serves its intended purpose or meets regulatory standards, must be pursued. As a result, many established utilities have capital plans that contain many such replacement projects. The question is how much investment should be made. The intent of this paper is to evaluate investment in infrastructure made by public water and sewer utility systems. What was found among the utilities in Florida that were evaluated was that more than half are underinvesting in their infrastructure. Some are not investing at all although more research is needed because it appears that many utilities make large investments periodically as opposed to using pay-as-you-go methods. Large scale investments like bond issues impact rates. Economies-of-scale remain for large utilities. Smaller utilities compete with larger ones to control rates. The data gathered indicates that utilities are underfunded, and under-invested. To reduce potential health risks, this needs to change. At the same time, trends appear to be a key to assess the potential for at risk utilities. Hence a future project would review data for the past 15 - 20 years for trends, identify patterns of altered investments and denote how the 2008 financial crisis changed the utility finances. A road to recapture lost revenues and make the infrastructure more resilient can then be accomplished.

流通数字化赋能全国统一大市场建设的机理与效应研究

建设全国统一大市场是加快构建新发展格局的基础支撑和内在要求。本文聚焦流通数字化发展对全国统一大市场建设的影响,实证检验流通数字化赋能全国统一大市场建设的传导机制和异质特征。研究发现,流通数字化发展能够显著促进全国统一大市场建设,且该研究结论具有较强的稳健性。机制检验结果表明,流通数字化发展能够通过加快创新要素流动、扩大企业规模、释放消费潜力等途径促进全国统一大市场建设。异质性检验结果表明,在基础设施水平、城镇化率和人口集聚程度较高地区,流通数字化对全国统一大市场建设的促进作用较为明显。进一步研究发现,流通数字化与统一大市场之间存在基于基础设施、城镇化率和人口集聚水平的门槛效应。本文研究结论为我国进一步加快流通产业的数字化转型、破除区域间要素流动壁垒、推进统一大市场建设提供了经验证据。

中国平台经济规模核算及预测

平台经济是数字经济的重要组成部分,测度平台经济的规模具有十分重要的现实意义。为此,本文结合国内外相关研究,将平台经济从数字经济的概念中剥离出来,对平台经济的生产与产出统计范围进行界定,构造平台经济规模核算框架,对2005—2021年平台经济增加值规模及其占GDP的比重进行统计测度,并通过指数平滑法和灰色预测模型对我国平台经济发展规模进行预测。本文研究结果为了解我国平台经济的发展现状及趋势、理解平台经济产业结构特征提供数据支撑,为把平台经济核算纳入现行国民经济核算体系提供参考建议。

我国畜牧业发展现状、存在问题及对策

畜牧业是我国农业农村经济的重要组成部分,对保障国家粮食安全和提高居民生活水平具有重要意义。近年来,我国畜牧业发展的内外部环境正在发生深刻的变化。本文分析了我国肉牛、生猪、肉鸡、肉羊产业的发展现状,发现我国畜牧业目前存在养殖场动物疫病风险加大,畜禽行业养殖环境约束趋紧,畜禽良种繁育能力不足,科技创新及人才支撑不足的问题。针对这些问题提出了构建完善的公共服务监管体系,科学提高疫情防控能力;推进规模化养殖和标准化生产;强化科技支撑,加快推进科技育种工作;提升技术研发能力,健全产业发展支撑体系等发展对策,以期为我国畜牧业健康发展提供理论参考。

基于高维标度评价法的数字经济发展水平评价

文章构建多种形式的高维标度评价法(MDSEM),该系列方法从评价对象间距离矩阵出发,更适用于小样本。当采用欧氏距离时,MDSEM等价于第一主成分评价法,基于熵权Minkowski距离的MDSEM可提高评价结果的一致性。基于MDSEM对2013—2020年中国数字经济发展水平进行测度并分析其时空分布特征,结果表明:中国数字经济发展水平呈现空间集聚特征,上海、江苏、浙江、北京、天津等东部地区省份相互促进、高水平运转,而大多数中西部地区省份则处于低-低弱集聚状态;区域差异较大,总体Gini系数先下降后略有上升,区间Gini系数贡献率在高位震荡下降,主要取决于东-中部、东-西部差异;从省份排名来看,2013—2020年,贵州、湖南、河北、江西等进步较大,而宁夏、新疆、黑龙江、山西等退步较大;5种数字经济发展状态较为稳定,跃级转移几乎不可能发生,稳态分布呈现橄榄球形状,较为合理。

数字经济发展对种植业碳排放效率的影响研究——基于中介和门槛效应的实证检验

农业源温室气体排放量(碳排放)仅次于工业,种植业作为农业的基础,其碳排放量在农业中占据较大比重,种植业碳减排对于“双碳”目标的实现具有重要意义。在“碳达峰、碳中和”的碳排放格局下,数字经济已成为推动种植业绿色低碳高质量发展的新引擎。本文在理论探讨基础上,结合2011—2021年中国31个省(自治区、直辖市,不包括中国香港地区、澳门地区和台湾地区)面板数据,综合利用固定效应回归模型、工具变量模型、中介效应模型、门槛效应模型,实证考察了数字经济发展与种植业碳排放效率之间的内在关系。研究发现,数字经济发展对种植业碳排放效率具有显著的正向影响,且存在农业生产功能与区域异质性;数字经济发展通过促进技术创新和规模经营来抑制种植业碳排放,且“技术创新效应”的贡献份额大于“规模经营效应”;数字经济发展对种植业碳排放效率的促进作用还受经济发展水平的影响,当经济发展水平低于阈值时,数字经济发展对种植业碳排放效率的影响并不显著,当经济发展水平超过阈值后,数字经济发展能够对种植业碳排放效率产生显著的提升效应。

规模经济与国有文艺院团效率增进——来自山西省的证据

规模经济是制造业和服务业供给主体必须追求的目标,艺术表演业也不例外。本文利用1989—2021年山西省国有院团的统计数据,构造长期平均成本产出函数,发现山西省国有文艺院团存在规模经济效应,但是成本产出组合偏离最优组合;国有经营院团生产效率优化空间较大,集体经营院团更能促进规模经济效应的形成。在做强做大文艺表演产业,提升国有文艺院团质量的同时,应降低院团运营中的管理冗余,充分发挥规模经济效应。

在浴火中重生——续论中国古代历史道路模式

在秦至清的两千多年里,中国历史走上了一条独特的道路,形成了固定的模式,表现为重建式演变与周期性循环两种运行方式。重建式演变是王朝政权颠覆后再生及王朝灭亡后新生的王朝诞生的现象,由于其在历史的长河中不断重复地发生,因而构成了一种演变的过程。这主要包括平乱式重建、造反式重建、割据式重建、分立式重建和混一式重建五种形式。周期性循环指历史以重复的面貌出现,陷入同一社会形态内政权的治乱兴衰循环上演、在曲折中不断变化的运动状态。中原王朝的更替循环、少数民族政权兴亡的循环、历史时期的治乱循环,是周期性循环的几种表现形式。小农经济的存在是重建式演变、周期性循环运行方式得以发生的基础性原因。小农经济具有极易遭受损害,而又极易得到恢复的两重性,当它遭受损害时王朝就陷入危机,当它得到恢复时王朝则兴盛。宗法制在皇权继承上的遗留,以及权力的滥用所表现出的外戚专权、宦官干政、奸臣弄权等,则是重建式演变、周期性循环发生的直接原因。

集聚外部性提升了农户全要素生产率吗?

技术进步和技术效率改善是促进粮食产业高质量发展,保障粮食安全的重要路径。随着水稻种植规模和稻农密度的增加,要素空间集中形成的集聚外部性不仅能够有效提升行业技术水平,而且还可以改善稻农技术非效率。基于湖南省2014-2020年间1248份水稻种植户微观数据,采用超越对数随机前沿生产函数模型,将表征集聚经济效应的种植规模和稻农密度,同时纳入前沿函数和技术非效率项中,综合考察集聚外部性对稻农全要素生产率的影响。研究结果发现:无论是水稻种植规模还是稻农密度,都显著地促进了水稻生产技术进步,提升了农户技术效率;两种集聚变量的产出弹性均为正,共同推动水稻产出前沿面外移;分地形和分农户种植面积的异质性回归结果与基准回归结果一致,结论具有稳健性。据此提出,水稻种植区要完善基础设施,利用土地政策满足农户需求,提升农业生产效率;利用土地整治等农田建设手段改善细碎化问题,推动村组生产专业化和规模化;通过改革土地制度、强化支持政策,结合地方实际优化农业结构,发挥水稻种植的规模和密度经济效应,提高全要素生产率。