Fuzzy Inventory Model under Selling Price Dependent Demand and Variable Deterioration with Fully Backlogged Shortages

The objective is to develop a model considering demand dependent on selling price and deterioration occurs after a certain period of time, which follows two-parameter Weibull distribution. Shortages are allowed and fully backlogged. Fuzzy optimal solution is obtained by considering hexagonal fuzzy numbers and for defuzzification Graded Mean Integration Representation Method. A numerical example is provided for the illustration of crisp and fuzzy, both models. To observe the effect of changes in parameters, sensitivity analysis is carried out.

How did the price and income elasticities of natural gas demand in China evolve from 1999 to 2015? The role of natural gas price reform

As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mechanism.Employing a set of unbalanced panel data for China’s 30 provinces covering 1999-2015,this study aims to estimate the evolving price and income elasticities of natural gas demand and explore the effect of natural gas price reform in China.For this purpose,a series of econometric techniques allowing for cross-sectional dependence and slope homogeneity is utilized.The results suggest that although natural gas demand in China still lacks negative price elasticity,the phenomenon is improving.Moreover,the estimates suggest that natural gas demand in China is indeed becoming increasingly sensitive to income changes.Our estimates also provide strong evidence in favor of the effect of natural gas price reform on the change in price elasticity as the price elasticity decreases in five of the seven regions.In addition,the results indicate large variations in the change in price and income elasticities of natural gas demand across China’s regions.Natural gas demand is becoming more price inelastic in Southwest China and Northwest China,while such demand in North China and East China responds less sensitively to income changes.These findings offer several policy suggestions for the reform of China’s natural gas market at the national and regional levels.

Fuzzy Inventory Model with Variable Production and Selling Price Dependent Demand under Inflation for Deteriorating Items

The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum total average costs. The model is integrated production inventory model developed where;the Demand has a direct linear impact on production rate. The model can be divided into four stages. In the first two stages with original production rate and subsequent change in production rate, inventory level rises. Third stage is time after the accumulation of inventory and before the deterioration starts, where demand which selling price dependent is depreciating the inventory level, while in the fourth stage deterioration occurs, which is considered to follow two parameter Weibull distribution. The back-order is not considered. Hexagonal fuzzy numbers are used to derive optimum solution and defuzzification by graded mean integration representation method. A numerical example is given to demonstrate the applicability of the purposed model and sensitivity analysis is carried out to reveal the impact of change in parameter values.

The Impact of Price on Chemical Fertilizer Demand in China

Since 1998,the national policies on chemical fertilizer in China have been concentrated in limiting price plus subsidizing,abolishing agricultural tax,giving direct subsidies to farmers,and other aspects.In order to analyze the impact of national policies on the consumption of chemical fertilizer,this article selects the consumption of chemical fertilizer per unit,chemical fertilizer price index and farmers'net income in different provinces during the period 1998-2007 as variables,to conduct regression analysis of chemical fertilizer expenditure function,and calculate the price elasticity and income elasticity of chemical fertilizer demand in different provinces over the decade based on the regression results.The results show that at present the basic consumption of chemical fertilizer for agricultural development in China is 0.35 t/hm 2 ,and the consumption of chemical fertilizer is excessive in some provinces;the chemical fertilizer market has not been really established,and the price has little impact on demand.This indicates that the chemical fertilizer is essential for agricultural economic development,and it increases along with the increase of farmers'income; the intervention of the national policy in chemical fertilizer price is a fundamental reason for the rising demand for chemical fertilizer.This also to some extent indicates that the policy effect of merely using environmental taxes to change farmers'consumption of chemical fertilizer is limited;there is a need to transform the existing policies purely promoting agricultural economic development,toward giving different subsidies in accordance with whether the farmers'fertilization pattern is beneficial to the environment.

Demand and Tight Stocks Driving Prices Higher

World cotton production and consumption are forecast to roughly balance at 25.1 million tons in 2010/11,as a result of a 15% rebound in production and a 2% increase in mill use.World ending stocks

Double Pressure on Power Grids——The demand for electricity is dropping while the electricity price is not adjusted properly

Since October 2008,China's social consumption of electricity had,for the first time,grown negatively compared to the same period of the previous year,and in November the negative growth range further expanded. The major pressure faced by the electricity industry has now turned from the contradiction between coal and electricity to electricity quantity. This is undoubtedly a true and new test to electricity enterprises which get used to high growth but are now suffering great losses. The reform of electricity system has already been in great difficulties and now is getting into a more serious situation. In order to help readers improve their knowledge and understanding of the current tough situation faced by the electricity industry and discuss how to alleviate and get through the difficulty resulted from the economic crisis "encountered once every one hundred years" by joint efforts of all parties concerned,a Seminar on Crisis and Countermeasures for Electricity Industry was held on November 20,2008. Here are some extracts from the speeches of four experts.

Analysis of an Inventory System for Items with Price-Dependent Demand and Time Dependent Three-Parameter Weibull Deterioration Function

In this research work we propose a mathematical model of an inventory system with time dependent three-parameter Weibull deterioration and price-dependent demand rate. The model incorporates shortages and deteriorating items are considered in which inventory is depleted not only by demand but also by decay, such as, direct spoilage as in fruits, vegetables and food products, or deterioration as in obsolete electronic components. Furthermore, the rate of deterioration is taken to be time-proportional, and a power law form of the price dependence of demand is considered. This price-dependence of the demand function is nonlinear, and is such that when price of a commodity increases, demand decreases and when price of a commodity decreases, demand increases. The objective of the model is to minimize the total inventory costs. From the numerical example presented to illustrate the solution procedure of the model, we obtain meaningful results. We then proceed to perform sensitivity analysis of our model. The sensitivity analysis illustrates the extent to which the optimal solution of the model is affected by slight changes or errors in its input parameter values.

我国肉鸡饲料价格波动特征及影响因素分析

文章旨在分析肉鸡价格波动特征及影响因素,有利于推动禽类养殖业健康稳定发展。基于2002年1月-2022年12月我国252个肉鸡饲料企业样本数据,在通过平稳性检验后,采用VAR模型和方差分解法,从肉鸡饲料价格、供给和需求方面分析引起我国肉鸡饲料价格波动的主要因素。结果显示,在供给层面,肉鸡饲料价格波动的主要影响因素为玉米存量和豆粕存量,第7期玉米存量和豆粕存量对当月肉鸡饲料价格的影响占比分别是30.78%和20.39%。在需求层面,在第7期农村居民人均可支配收入和可繁殖母鸡存栏量对肉鸡饲料价格的影响占比较高,分别为9.06%和6.87%。研究表明,肉鸡饲料价格波动受肉鸡饲料自身价格影响程度最大,随后依次为玉米存量、豆粕存量、农村居民人均可支配收入、可繁殖母鸡存栏量、鱼虾肉价格、肉鸡存栏量、牛肉价格和城镇居民人均可支配收入。

政府补贴下考虑需求不确定的动力电池回收定价决策

在供应链的实际运行中,市场需求的不确定使新产品和再制造产品成本及价格不确定,将直接影响供应链节点企业的定价决策和最优利润。本文以动力电池为主要研究对象,基于政府补贴政策,构建由新能源汽车动力电池制造商、零售商、第三方回收商三者为参与主体的动力电池闭环供应链。在市场需求量不确定性和再制造竞争情景下,新产品和再制造品的市场需求量随机波动,分析批发、零售、回收价格、政府补贴及闭环供应链中各节点企业期望收益。运用算例仿真进行灵敏度分析,研究需求不确定下各要素的变化规律。研究表明,各节点企业之间应加强合作,信息共享、协商制定价格,规避因消费市场需求不确定带来的风险,为政府实施补贴激励措施提供理论支持。

2023年中国成品油行业运行特点与近期展望

2023年,中国炼油产能再创新高,炼厂开工率回升,成品油产量大幅增长;成品油消费恢复至疫情前水平,不同品种恢复节奏存在差异,航空煤油消费明显恢复;成品油消费结构变化明显,供需差量扩大;在国际原油价格高位宽幅震荡背景下,成品油批发价格小幅增长;成品油商业库存“汽跌柴涨”,油库建设需求旺盛;成品油进口大幅下降,俄罗斯成为中国成品油进口主要来源国,成品油出口量继续增加,主要出口至新加坡;多项市场专项整治方案出台,规范成品油市场运行,推动行业高质量发展。2024年,中国成品油市场监管仍将持续完善,炼油行业将继续扩能,成品油产量将继续增长,成品油消费将回归低速增长通道,国际原油价格将宽幅震荡加剧成品油市场价格波动风险。

供需评价异化视角下农业生产托管服务价格形成机制存在的问题——来自江汉平原的调查问卷

农业生产托管服务价格是影响托管服务供给和需求的重要因素。基于江汉平原农业生产托管服务供需双方对托管服务价格评价的调查结果,分析了农业生产托管服务价格形成机制的现状与存在的问题。结果表明,目前农业生产托管服务价格并不是供需双方一致达成的均衡价格,农业生产托管服务市场属于不完全市场,托管服务价格水平普遍偏高,供给方有让利给需求方的空间和动机,但存在供需错配问题,托管服务价格及补贴政策对供需的调节作用并没有得到充分发挥。为此,应完善供需沟通渠道,加强服务标准建设,大力发展新型农业经营方式,优化托管补贴对象,加强政策宣传和明确补贴指向,以促进农业生产托管服务价格形成机制的完善。

2024年我国无烟煤市场发展与展望

通过对宏观政策以及产业政策动态等多维度进行剖析,对无烟煤下游行业的消费现状和趋势进行详细分析和预测。介绍了我国无烟煤资源分布、生产和进口现状,对我国无烟煤生产和进口趋势进行了预测。综合分析供需、成本、政策等影响无烟煤价格的因素,特别是需求和供应关系,对2024年无烟煤价格走势进行了定性分析。整体认为,2024年,我国无烟煤将处于供需紧平衡状态,但较2023年略有宽松;价格中枢有望小幅下移,但仍将处于相对较高的位置。

含分布式新能源和需求响应负荷的虚拟电厂定价机制及优化调度

面对电网中分布式风电、光伏发电以及柔性负荷的广泛接入,将这些资源通过虚拟电厂(VPP)进行聚合,采用合理的电价机制来引导用户参与需求响应,可以有效提升新能源的消纳能力并降低整体运营成本。传统的分时电价机制往往难以实现需求响应负荷与新能源出力的良好匹配,可能会导致需求响应的不合理或过度反应。为此,针对包括分布式风电、分布式光伏发电和柔性负荷的VPP,提出了一种基于新能源出力的VPP内部定价机制,并设置电力交易优先级来引导VPP内部各资源优化运行,以VPP的整体运营成本最小化为目标,构建了一个VPP优化调度的混合整数线性规划模型。基于内蒙古某地区的实际数据进行仿真计算,结果表明,与基于传统分时电价的优化结果相比,该方法能显著提高新能源的利用率并降低VPP的运行费用。

考虑分时电价下需求响应的用户侧储能优化配置

针对用户侧储能在投资与运行方面经济性不足的问题,提出一种考虑分时电价下需求响应的用户侧储能规划与运行两阶段优化策略.第一阶段通过建立分时电价优化模型,采用粒子群(PSO)和序列二次规划(SQP)混合算法求解得出分时电价策略,第二阶段基于第一阶段得出的分时电价策略建立考虑两个时间尺度的储能双层优化模型,上层模型以最大化全寿命周期净收益为目标优化长时间尺度的储能配置,下层模型以最大化日运行收益为目标优化短时间尺度的储能运行,结合混合整数线性规划方法和KKT条件,调用CPLEX求解器进行求解,通过两阶段的联合优化,实现用户侧储能配置和运行收益综合最优.最后,结合实例进行仿真,结果表明所提方法可以有效提高用户侧储能系统的经济性.

随机需求下考虑竞争因素的众包快递平台定价策略研究

伴随着“共享经济”模式的高速发展,众包快递模式应运而生。在此背景下,文章针对众包快递平台需求呈现随机且波动变化的特点,考虑众包快递平台之间的竞争,基于古诺竞争博弈理论,建立了考虑市场需求和市场竞争的动态定价模型,并运用变分法求解最优的价格问题。由于市场需求的变动,众包快递平台的最优服务价格会发生动态的改变,同时也受到平台间竞争的影响,最优服务价格将随着平台之间竞争强度的变化而变化。

2023年中国石油焦市场分析及2024年预测

截至2023年年底,中国延迟焦化能力达到1.48亿吨/年。2023年中国石油焦产量达到3173万吨,主营炼厂产量占比为57%,地方炼厂占比43%;以高硫焦为主,占比80%以上。2023年,中国进口石油焦1602万吨,出口石油焦仅19万吨,净进口量1583万吨。2023年中国石油焦表观消费量达到4516万吨。虽然中国石油焦价格总体呈上升态势,但与上年相比,2023年中国石油焦价格暴跌。预计2024年中国石油焦市场的国内产量为3150万吨,净进口量为1400万吨,库存变化为下降200万吨,表观消费量为4750万吨。石油焦作为“减油增特”的特色炼油产品之一,对中国成品油市场调节能力非常有限,建议生产企业应该随着中国石油焦需求动能的变化,积极拓展负极材料相关客户,根据其数量、质量需求灵活调整石油焦生产和销售策略。

基于数字孪生的智能制造企业产品定价决策

为实现智能制造企业服务化转型下客户对产品需求实现和交付时间的更高要求,考虑数字孪生的技术成本、需求实现能力和交付时间等因素,分别建立生产型智能制造企业和基于数字孪生的服务型智能制造企业的竞争性定价决策模型,对模型均衡解及仿真结果进行对比分析。研究发现:当虚实一致程度带来的效用增益高于数字孪生技术成本时,服务型智造企业才有动力投入数字孪生,但长远看技术成本的增长会被更高的服务效用所抵消;在虚实一致程度边界内外客户对需求实现能力的敏感系数变化对两类智造企业产品定价、需求和利润会产生不同影响;随着客户对产品交付时间的敏感程度增加,数字孪生缩短产品交付时间能够改善服务型智造企业因时间而导致的定价劣势。

中国丙烯及下游产品发展回顾及展望

介绍了2023年中国丙烯及下游产品的供需情况,包括产能、产量、进口量、出口量、消费量及当量消费量,对2023年中国丙烯及下游产品价格及利润情况进行分析,并对2024年中国丙烯及下游产品发展进行展望。

基于动态电价机制的配网运营商与用户储能商双层协调多目标优化策略

为在电力市场和调度运用中发挥用户侧分布式储能的价值,充分利用电价的优化调节能力,提出考虑负荷需求响应的多目标双层动态电价模型。其中,上层以区域配网代理运营商运营成本和平均负荷波动率最小为目标,下层考虑储能商负荷需求响应,以各储能商运营成本最小为目标。此外,采用改进优劣解距离法对模型求得的Pareto最优解集进行多属性决策,以避免传统优劣解距离法中人为赋权的主观性。最后,决策出最优的内部电价、充放电计划和负荷安排。算例表明,该策略可以降低储能商的运行成本,提高区域配网运营商的收益与区域供电可靠性,同时有利于平滑负荷曲线。

考虑需求响应及不确定性的综合能源优化调度

如何在区域综合能源系统中建立有效的需求侧模型,对于需求响应政策的实施至关重要。为提高用户参与需求响应积极性,引入实时定价机制,同时考虑系统的经济低碳性和电气热用户的用能满意度,构建兼顾系统和用户利益的综合需求响应主从博弈模型。针对用户参与需求响应的不确定性,引入贝叶斯方法更新负荷曲线。算例分析表明,所提博弈模型及贝叶斯方法能够有效平衡系统和用户之间的利益,提高了综合需求响应的可靠性。