Multi-objective linear fractional inventory model with possibility and necessity constraints under generalised intuitionistic fuzzy set environment

This study presented a multi-objective linear fractional inventory (LFI) problem with generalised intuitionistic fuzzy numbers. In modelling, the authors have assumed the ambiances where generalised trapezoidal intuitionistic fuzzy numbers (GTIFNs) used to handle the uncertain information in the data. Then, the given multi-objective generalised intuitionistic fuzzy LFI model was transformed into its equivalent deterministic linear fractional programming problem by employing the possibility and necessity measures. Finally, the applicability of the model is demonstrated with a numerical example and the sensitivity analysis under several parameters is investigated to explore the study.

A Weighted Goal Programming Model for the DASH Diet Problem: Comparison with the Linear Programming DASH Diet Model

A Linear Programming DASH diet model for persons with hypertension has previously been formulated and daily minimum cost diet plans that satisfy the DASH diets’ tolerable intake level of the nutrients for 1500 mg a day Sodium level and different daily calorie levels were obtained using sample foods from the DASH diet eating plan chart. But the limitation in the use of linear programming model in selecting diet plans to meet specific nutritional requirements which normally results in the oversupply of certain nutrients was evident in the linear programming DASH diet plan obtained as the nutrient level of the diet plans obtained had wide deviations of from the DASH diets’ tolerable upper and lower intake level for the given calorie and sodium levels. Hence the need for a model that gives diet plans with minimized nutrients’ level deviations from the DASH diets’ tolerable intake level for different daily calorie and sodium level at desired cost. A weighted Goal Programming DASH diet model that minimizes the daily cost of the DASH eating plan as well as deviations of the diets’ nutrients content from the DASH diet’s tolerable intake levels is hereby presented in this work. The formulated weighted goal programming DASH diet model is further illustrated using chosen sample foods from the DASH food chart as used in the work on the linear programming DASH diet model for a 1500 mg sodium level and 2000 calories a day diet plan as well as for 1800, 2200, 2400, 2600, 2800 and 3000 daily calorie levels. A comparison of the DASH nutrients’ composition of the weighted Goal Programming DASH diet plans and those of the linear programming DASH diet plans were carried out at this sodium level and the different daily calorie levels. It was evident from the results of the comparison that the weighted goal programming DASH diet plans has minimized deviations from the DASH diet’s tolerable intake levels than those of the linear programming DASH diet plans.

Optimal design of modular dual-field modulated permanent magnet linear motors with thrust characteristics

To reduce thrust ripple and cost and improve the average thrust of permanent magnet linear motors,a modular dual-field modulation permanent magnet linear motor was studied,and the parameters were optimized.First,sensitive parameters were selected using the Taguchi method,and then the optimal variables were sampled using the optimal Latin hypercube experimental design method and an ensemble of surrogates model of optimization objectives,and its accuracy was verified.Next,a multi-objective particle swarm optimization algorithm was used to optimize the purpose of“maximum average thrust and minimum thrust ripple”,and the Pareto front of average thrust and thrust ripple was obtained.Finite element analysis showed that the optimized modular dual flux-modulation permanent magnet linear motor(MDFMPMLM)had a 29.5%reduction in thrust ripple and a 5%increase in average thrust compared to the original motor.This study provided an effective method for improving the performance of permanent magnet linear motors.

A Hybrid Inexact Optimization Model for Land-use Allocation of China

Land scarcity has become the prominent obstacle on the way to sustainable development for China. Under the constraints of land shortage, how to allocate the finite land resources to the multiple land users in China considering various political, environmental, ecological and economic conditions have become research topics with great significance. In this study, an interval fuzzy national-scale land-use model(IFNLM) was developed for optimizing land systems of China. IFNLM is based on an integration of existing interval linear programming(ILP), and fuzzy flexible programming(FFP) techniques. IFNLM allows uncertainties expressed as discrete interval values and fuzzy sets to be incorporated within a general optimization framework. It can also facilitate national-scale land-use planning under various environmental, ecological, social conditions within a multi-period and multi-option context. Then, IFNLM was applied to a real case study of land-use planning in China. The satisfaction degree of environmental constraints is between 0.69 and 0.97, the system benefit will between 198.25 × 1012 USD and 229.67 × 1012 USD. The results indicated that the hybrid model can help generate desired policies for land-use allocation with a maximized economic benefit and minimized environmental violation risk. Optimized land-use allocation patterns can be generated from the proposed IFNLM.

Optimization of train plan for urban rail transit in the multi-routing mode

The train plan of urban rail transit under multi-routing mode can be divided into three parts： train formation, train operation periods and corresponding train counts of each routing in each period. Based on the analysis of passen- ger＇s general travel expenses and operator＇s benefits, the constraints and objective functions are defined and the multiobjective optimization model for the train plan of urban rail transit is presented. Factors considered in the multi- objective optimization model include transport capacity, the requirements of traffic organization, corporation benefits, passenger demands, and passenger choice behavior under multi-train-routing mode. According to the characteristics of this model and practical planning experience, a three-phase solution was designed to gradually optimize the train formarion, train counts as well as operation periods. The instance of Changsha Metro Line 2 validates the feasibility and efficiency of this approach.

Application of PIMS Software in Monthly Planning of Refinery Production

This article describes the application of the PIMS software in formulating monthly refining production plan. Application of the PIMS software can help to solve a series of problems related with monthly plan of refining production such as optimized selection of crude and feedstocks, optimized selection of production scale and processing scheme, identification of bottlenecks and their mitigation,optimized selection of turnaround time and optimized selection of operating regime, which have increased the economic benefits of refining enterprises. With the further development and improvement of models the PIMS software will play an increasingly important role in formulating monthly plans of refining operations and production management at refineries. This article also explores the problems existing in refinery monthly planning, and has made recommendations on developing and improving models and reporting system, enhancement of basic data acquisition, model maintenance personnel and staff training.

Evaluation and advancement of the integrated circular economy model of farming and stock raising

The integrated circular economy model of farming and stock raising(ICEMFSR)has attracted increased attention as an effective model for solving the current irrational allocation of agricultural resources and realizing the agricultural value-added industrial chain.This study uses emergy analysis to comprehensively examine and evaluate the economic benefits,environmental pressures,and sustainable development levels of ICEMFSR in Shucheng County,China.The results show that the ICEMFSR possesses the value of popularization with optimally allocated resources in the studied region,in which the emergy yield ratio(EYR),emergy loading ratio(ELR),and emergy sustainable index(ESI)in this model accounted for 3.59,1.25,and 2.89,respectively.This result indicates a leading position in the national agricultural system.Hence,this study constructs a new model based on the coupling of emergy evaluation and multi-objective linear programming to study ICEMFSR.Consequently,the EYR,ELR,and ESI respectively varied by +24.23%,10.40%,and +38.06%after replanning of ICEMFSR.This variation implies a significant improvement in the sustainable development level of the model.In addition,the optimized scenario design for key substances is proposed based on traceability and the reduce-reuse-recycle principle,including biogasification of crop straw and enhancement of crop scientific planting capacity.

Analysis of Energy Storage Operation Configuration of Power System Based on Multi-Objective Optimization

Driven by the goal of“carbon neutrality,”the increase in use of renewable energy power systems will be inevitable in the future.Uncontrolled output power and random volatility make it difficult to balance power in real time during system operation.Therefore,energy storage is considered to be an effective way to ensure the real-time balance of system power.However,cost of energy storage is relatively expensive.As a solution,energy storage can be used to balance the system power in order to reduce system operating costs.Taking the high proportion of wind power systems as an example,the impact of the“supply side”low-carbon transformation on the economics and reliability of power system operation is explored.In order to solve the problem of power system operation configuration optimization under the background of“carbon neutrality,”this paper establishes a multi-objective programming model.

低轨星座传感器资源调度的自主任务规划建模方法

低轨星座传感器资源的优化调度是复杂多约束下的任务规划问题,为了满足多个运动目标全程跟踪与监视的资源实时优化调度需求,提出一种星上自主快速求解的规划模型.在对自主任务规划问题进行详细建模的基础上,考虑各项约束条件与优化因素,将原问题转化成简易的0-1线性整数规划模型,并构建多目标跟踪试验场景对所提方法进行了仿真验证.仿真结果表明,基于简易规划模型的资源调度可实现多目标的全程跟踪与监视.

线性规划的历史与发展

本文介绍了线性规划的起源与发展过程,对比了丹齐格与坎托罗维奇各自在线性规划方面的贡献.

一种基于Petri网的多机器人路径规划建模方法

月球基地建设是当前各国月球探测与开发计划的核心使能技术之一。然而,为消除高昂的运输成本和有限载人航天技术的约束,使用多机器人团队建造月球基地的新研究方案被提出,该方案的关键是如何实现多机器人针对复杂任务的路径规划。为此,以月球基地建设场景中的探测采集区域、采集月壤、搬运月壤等作为复杂的任务输入,研究了一种基于Petri网模型的多机器人路径规划建模方法。构建了多机器人运动的Petri网模型;使用线性时序逻辑(linear temporal logic,LTL)语言描述月球基地建设的相关任务;将Petri网模型和LTL公式结合求解得到多机器人路径;在Matlab软件中进行仿真验证,并与使用切换系统的建模方法进行对比。结果表明,使用Petri网模型所需的建模总时间比切换系统模型单个任务的建模时间减少2个数量级,说明建立的Petri网多机器人模型具有避免维度爆炸、计算高效等优势。

高速公路ETC门架和收费站车辆轨迹数据数学模型研究

采用蒙特卡洛法对高速公路车辆轨迹数据进行预处理,模拟得出车流量的时间分布特征和空间分布特征.采用二分法遍历车辆轨迹数据,得出各电子收费系统(ETC)门架的漏失记录率以及最易被漏失的车型.建立收费站车流量与所有收费站总车流量的多元线性回归模型,得出收费站车流量与所有收费站总车流量的关系.建立各收费站车道数量和应急收费系统数量的单目标规划模型,得出收费站通行顺畅且车道和应急收费系统建设费用最少时,各收费站车道数量以及应急收费系统数量.采用G(1,1)灰色模型预测出15个收费站间各路段未来24 h的车流量变化趋势,其与实际车流量变化趋势基本吻合,因此可将各路段预测车流量作为参考,为高速公路管理部门改进交通状况提供改进依据.

A novel framework of ecological risk management for urban development in ecologically fragile regions: A case study of Turpan City, China

Assessing and managing ecological risks in ecologically fragile areas remain challenging at present.To get to know the ecological risk situation in Turpan City,China,this study constructed an ecological risk evaluation system to obtain the ecological risk level(ERL)and ecological risk index(ERI)based on the multi-objective linear programming-patch generation land use simulation(MOP-PLUS)model,analyzed the changes in land use and ecological risk in Turpan City from 2000 to 2020,and predicted the land use and ecological risk in 2030 under four different scenarios(business as usual(BAU),rapid economic development(RED),ecological protection priority(EPP),and eco-economic equilibrium,(EEB)).The results showed that the conversion of land use from 2000 to 2030 was mainly between unused land and the other land use types.The ERL of unused land was the highest among all the land use types.The ecological risk increased sharply from 2000 to 2010 and then decreased from 2010 to 2020.According to the value of ERI,we divided the ecological risk into seven levels by natural breakpoint method;the higher the level,the higher the ecological risk.For the four scenarios in 2030,under the EPP scenario,the area at VII level was zero,while the area at VII level reached the largest under the RED scenario.Comparing with 2020,the areas at I and II levels increased under the BAU,EPP,and EEB scenarios,while decreased under the RED scenario.The spatial distributions of ecological risk of BAU and EEB scenarios were similar,but the areas at I and II levels were larger and the areas at V and VI levels were smaller under the EEB scenario than under the BAU scenario.Therefore,the EEB scenario was the optimal development route for Turpan City.In addition,the results of spatial autocorrelation showed that the large area of unused land was the main reason affecting the spatial pattern of ecological risk under different scenarios.According to Geodetector,the dominant driving factors of ecological risk were gross domestic product rating(GDPR),soil type,population,temperature,and distance from riverbed(DFRD).The interaction between driving factor pairs amplified their influence on ecological risk.This research would help explore the low ecological risk development path for urban construction in the future.

基于线性规划优化小精细化工企业的生产措施

由于小精细化工企业生产灵活、工艺复杂、对成本和利润控制严格,因此,对生产工艺的优化,就成为小精细化工企业生产措施改进的主要内容之一。文章结合小精细化工企业的生产状况以及在该状况条件下相应的约束因素等,采用运筹学线性规划法构建最优计划数学模型,利用计算软件就具体数据进行求解,得到生产计划的最优解。

基于城市历史景观的独库公路多元价值保护与韧性管理模式研究

独库公路文化景观廊道,作为天山中段国家公园潜力区的核心纽带,具有不可估量的自然—文化遗产保护价值,也是解决跨区域性核心区与缓冲区之间文化断裂问题的关键。城市历史景观是强调对于区域环境活态性、整体性、再生性的遗产管理范式,旨在促进发展中寻求保护的双重目标。线性遗产空间的复合属性正是韧性保护的核心要点,以独库公路遗产廊道为研究对象,基于沿线资源现状问题,对独库公路全段的景观特征认知及遗产要素进行定位识别,分段关联性分析不同时期演变层积出的文化多样性发展过程;从宏观格局到中观形态再到微观场域进行分级保护管理,通过联动路域的遗产地、自然保护地、特色景观节点、停车点等重要历史文化遗产,构建线性遗产空间网络,以便坚实城市历史景观方法的应用与落位;最后,以独库自然—文化遗产基因库的建设实践为基础,将遗产廊道的全要素价值载体分级厘清,利用“生态韧性—文化韧性—管理韧性—消费韧性”的动态管理策略,实现活化利用交旅基底、盘活区域文旅资源、赋能沿线产旅路径的多元协同保护模式。研究成果以期推进独库文化遗产系统性保护与韧性发展,并为同类研究提供借鉴。

我国计划生育政策调整能否改变生育意愿?

关于计划生育政策对生育意愿的影响,以往研究往往从主观猜测的角度进行阐述。文章基于量化研究推进了人口学领域中这一主题研究。将理想子女数作为衡量生育意愿的指标,采用均值分析、面板线性双重差分模型,基于样本所属生育政策对比分析了全面二孩政策出台前后同一人群的生育意愿。双重差分模型结果显示,受全面二孩政策调整影响,原属一孩半政策的女性生育意愿平均提高了0.164个孩子。这与一孩半政策女性对子女较多的需求效应有关,又与全面二孩政策相配套的政策措施降低了生育经济成本有关。全面二孩政策并没有提高其他人群的生育意愿。据此,建议重点支持原属于一孩半政策妇女的生育,促其将生育意愿转换成生育现实。

基于机理的蒸汽裂解模型在生产计划优化中的应用探索

以某炼化一体化企业的乙烯蒸汽裂解装置为例,生产计划优化模型实现与蒸汽裂解机理模型的无缝集成是非常有意义的探索。介绍了乙烯蒸汽裂解装置在生产计划优化模型中采用非线性建模技术,集成了裂解炉模拟机理模型,并采用回归工具得到适用于生产计划优化模型的外挂机理模型XLP文件,用于模型的优化计算,可优选乙烯原料选择、优化裂解操作参数,得到更加精确的装置收率计算结果,实现从原油到石脑油的性质传递和计算,提高了企业计划优化模型的精细化水平,为企业优化生产、降本增效提供了有力支撑。

湖羊圈养的空间利用率优化方案研究

为提升湖羊规模化圈养养殖场的空间利用率,结合湖羊繁殖和育肥的特征,以及标准羊栏的规格与使用要求,任选连续生产条件下母羊生产的一个完整周期(229天)进行分析,以每日安排自然交配的母羊羊栏数量(或组数、羊只数量)和公羊数量为决策变量,根据繁殖期、育肥期等假设条件,寻找羊栏使用量与决策变量间的关系,建立羊栏使用数量、公羊与基础母羊配置比例、交配期所需种公羊羊栏量等约束条件。构建整数线性规划数学模型,获得可行的种公羊和基础母羊数量及羊栏使用方案,并进一步分析、验证、比较,确定连续生产条件下年化出栏羊只数量最大的生产计划及羊栏使用方案。

计及源-荷不确定性及需求侧响应的多主体综合能源系统两阶段鲁棒优化配置

基于峰谷电价差的需求侧负荷参与调度,是实现源荷平衡和促进可再生能源消纳的重要策略。为应对源-荷不确定性对电源容量管理带来的挑战,该文提出了一种考虑源-荷不确定性及需求侧响应的多主体综合能源系统两阶段鲁棒优化配置策略。在第一阶段,优化计算风电、光伏和储能的容量配置;第二阶段,规划风电、光伏、储能和燃气轮机的实际出力。模型综合考虑了多类型多负荷需求响应约束,并通过引入不确定性调节参数来表征源-荷不确定性的波动程度;同时,采用整数变量将原模型转化为混合整数线性优化问题,并利用双层列生成循环算法。仿真结果表明,所提策略能够灵活计算微电网电源配置方案及出力工况,为多源微网的电源容量配置策略和激发需求侧与电网之间灵活互动提供了理论支撑。

基于多目标优化模型的扇叶最优分组与排列方案

衡量某种机械单片扇叶结构优劣的指标有“质量”与“转动频率”两种参数,为了合理地装配整个风扇,需要相邻组的扇叶质量差达到最小,同时相邻叶片的频率差达到最大。首先构建一个单目标优化的质量分组模型,其后引入递推型动态规划算法,使得相邻组的扇叶质量差达到最小。同时考虑转动频率的影响,再建立一个多目标优化的质量分组模型,采用动态权重线性加权法,通过对比不同权重下相邻扇叶组的最大质量差和相邻扇叶的最大频率差,发现当A目标和B目标的权重均为0.5时,该模型所给出的方案效果最佳。