Multi-Objective Optimization of Multi-Product Parallel Disassembly Line Balancing Problem Considering Multi-Skilled Workers Using a Discrete Chemical Reaction Optimization Algorithm

This work investigates a multi-product parallel disassembly line balancing problem considering multi-skilled workers.A mathematical model for the parallel disassembly line is established to achieve maximized disassembly profit and minimized workstation cycle time.Based on a product’s AND/OR graph,matrices for task-skill,worker-skill,precedence relationships,and disassembly correlations are developed.A multi-objective discrete chemical reaction optimization algorithm is designed.To enhance solution diversity,improvements are made to four reactions:decomposition,synthesis,intermolecular ineffective collision,and wall invalid collision reaction,completing the evolution of molecular individuals.The established model and improved algorithm are applied to ball pen,flashlight,washing machine,and radio combinations,respectively.Introducing a Collaborative Resource Allocation(CRA)strategy based on a Decomposition-Based Multi-Objective Evolutionary Algorithm,the experimental results are compared with four classical algorithms:MOEA/D,MOEAD-CRA,Non-dominated Sorting Genetic Algorithm Ⅱ(NSGA-Ⅱ),and Non-dominated Sorting Genetic Algorithm Ⅲ(NSGA-Ⅲ).This validates the feasibility and superiority of the proposed algorithm in parallel disassembly production lines.

Hydraulic model optimization of a multi-product pipeline

An optimization model is established for a multi-product pipeline which has a known delivery demand and operation plan for each off-take station.The aim of this optimization model is to minimize the total pumping operation cost,considering not only factors including the energy equilibrium constraint,the maximum and minimum suction and discharge pressures constraints of pump stations,and pressure constraint at special elevation points,but also the regional differences in electricity prices along the pipeline.The dynamic programming method is applied to solve the model and to find the optimal pump configuration.

Integrated Manufacturing Cell Formation Technology Orienting Multi-product Type and Variant Volume Production

What is pursued by multi-product type and variant volume（MPTVV） production is rapid response and quick switching,so that structure of transferring line in manufacturing system is no longer unalterable.Cell formation（CF） algorithm is the key technology of cellular manufacturing system（CMS）.Currently,CF methods are mainly extended on the idea of group technology（GT） that covers a lot on analysis of resource capability matching and its algorithm.Various constraints are considered,but seldom utilized comprehensively.Aimed to the problem of manufacturing cell（MC） formation under MPTVV production mode,integrated formation technologies for typical MC as group type of cell（GC）,flow type of cell（FC） and inherited cell（IC） are presented based on technical analysis of CF.Oriented to practical production constraints like delivery time,product batch,equipment ability,key machine,key part and machine sharing,etc,an integrated formation model is constructed and internal interrelations of these constraints are analyzed synthetically.Ulteriorly,formation goals of types of MCs and their formation procedures under joint effect of formation constraints and rules are spread.In case study,three highly balanced GC are formed first;then FC formation are implemented based on the same data which indicate good balancing effect of cell load and flow-style production for key tasks;When task is adjusted,a new scheme is constructed on the result of FC configuration by using IC formation method,and more optimal performance of flow-style production is manifested.The proposed comparative study of different type of cells strongly explains the validation of integrated MC formation in support of rapid manufacturing resource transformation under MPTVV production mode.

Information Flow Scheduling in Concurrent Multi-Product Development Based on DSM

Multi-product collaborative development is adopted widely in manufacturing enterprise, while the present multi-project planning models don＇t take techni- cal/data interactions of multiple products into account. To decrease the influence of technical/data interactions on project progresses, the information flow scheduling models based on the extended DSM is presented. Firstly, infor- mation dependencies are divided into four types： series, parallel, coupling and similar. Secondly, different types of dependencies are expressed as DSM units, and the exten- ded DSM model is brought forward, described as a block matrix. Furthermore, the information flow scheduling methods is proposed, which involves four types of opera- tions, where partitioning and clustering algorithm are modified from DSM for ensuring progress of high-priority project, merging and converting is the specific computation of the extended DSM. Finally, the information flow scheduling of two machine tools development is analyzed with example, and different project priorities correspond to different task sequences and total coordination cost. The proposed methodology provides a detailed instruction for information flow scheduling in multi-product development, with specially concerning technical/data interactions.

Rule-based scheduling of multi-stage multi-product batch plants with parallel units

A novel rule-based model for multi-stage multi-product scheduling problem(MMSP)in batch plants with parallel units is proposed.The scheduling problem is decomposed into two sub-problems of order assignment and order sequencing.Firstly,hierarchical scheduling strategy is presented for solving the former sub-problem,where the multi-stage multi-product batch process is divided into multiple sequentially connected single process stages,and then the production of orders are arranged in each single stage by using forward order assignment strategy and backward order assignment strategy respectively according to the feature of scheduling objective.Line-up competition algorithm(LCA)is presented to find out optimal order sequence and order assignment rule,which can minimize total flow time or maximize total weighted process time.Computational results show that the proposed approach can obtain better solutions than those of the literature for all scheduling problems with more than 10 orders.Moreover,with the problem size increasing,the solutions obtained by the proposed approach are improved remarkably.The proposed approach has the potential to solve large size MMSP.

The Budget Constrained Multi-product Newsboy Problem with Reactive Production:A Problem from Entrepreneurial Network Construction

This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be used to describe the status of entrepreneurial network construction. We use the Lagrange multiplier procedure to deal with our problem, but it is too complicated to get the exact solu-tion. So we introduce the homotopy method to deal with it. We give the flow chart to describe how to get the solution via the homotopy method. We also illustrate our model in both the classical procedure and the homotopy method. Comparing the two methods, we can see that the homotopy method is more exact and efficient.

The Reconstruction Technique of Multi-Product Production and MINLP Mathematical Modelling

Low efficiency, negative impacts on the environment and non-profitable operations are the main shortcomings of out-dated industrial processes. Such systems can be reconstructed and improved in the direction of multi-product operations. The study of this article focuses on the development of a method for multi-product operations by reconstructing out-dated industrial processes. This article contains the theory of a developed method that enables the updating of existing process units and integrated systems on the basis of reconstruction scenarios and pathways. The goals of the set out method are: 1) to maintain the existing process units and chemical plants to a greater extent, 2) to enable the potential for finding new process alternatives and technological solutions, 3) to provide a streamlined operation for all subsystems and total systems, 4) to promote environmental and social responsibilities, and 5) to apply the concept of the presented reconstruction method to non-profitable industrial processes. In regard to multi-product operations, a conceptual model is a suitable tool for the reconstruction of industrial processes. It connects several software tools and so enables quick decision-making between process alternatives. A reconstruction method provides foresight into the possible improvements to existing industrial processes. In comparison with the indirect synthesis of DME (simple reconstruction pathway), the lower operating costs from the direct synthesis of DME (complex reconstruction pathway) were confirmed.

重点产业政策与中国企业出口产品组合调整

本文利用中国工业企业数据和海关数据,考察了重点产业政策对多产品企业出口产品组合调整的影响。研究结果发现,重点产业政策促进了企业出口产品集中度的提高和出口产品范围的扩大。这种促进作用在民营企业、外资企业、一般贸易企业和东部地区企业中更为突出。重点产业政策通过缓解企业融资约束和激励企业技术创新等渠道影响企业出口行为的调整,同时,激烈的国内同业竞争和目的地市场竞争进一步强化了产业政策效应。除了影响受支持企业的出口行为,重点产业政策还能通过融资和创新的溢出效应带动相同二位码行业内非重点企业调整出口产品组合,培育其竞争优势。

基于多裂缝扩展形态的水平井压裂施工参数优化

为研究多簇压裂裂缝扩展的实际形态对水平井产能预测的影响,进而科学指导压裂施工设计,基于位移不连续法(DDM)研究了布缝间距和布缝数量2个因素对多裂缝扩展形态、流量分配的影响,并采用CMG数值模拟软件结合吉林油田H区块的实际地质参数,建立了单水平井压裂均质模型,基于产能最大化,优选出最佳的压裂施工参数。结果表明,随着簇数增加,进液量百分比极差和裂缝长度极差先增大,后略微减小;当进行4簇射孔压裂时,裂缝2、3的进液量百分比和缝宽都过小;簇间距对多裂缝扩展均匀程度有着重要影响。为了保证多裂缝扩展均匀程度更高,在实际压裂施工中应采用较大的簇间距。在H区块地层参数条件下,最优裂缝簇数为3簇,最佳簇间距为40 m,最优裂缝半长为120 m,最佳裂缝导流能力为10μm^(2)·cm。该区块适合使用黏度30 MPa·s、排量6 m^(3)/min的压裂液进行压裂。

多向加权Tsallis熵最大化导向的自动阈值分割方法

受噪声或随机细节、目标和背景的大小比例、成像时的点扩散等不同因素的影响,许多图像的灰度直方图呈现为无模态、单模态、双模态或者多模态样式.为了在统一框架内处理这4种不同模态情形下的自动阈值选择问题,本文提出了一种多向加权Tsallis熵最大化导向的自动阈值分割方法(Multi-directional Weighted Tsallis Entropy,MWTE).基于新设计的反正切方向性卷积核的多尺度乘积效应,该方法将不同模态的灰度直方图转化为统一的单模态右偏灰度直方图.在4个不同方向上提取出这种特殊的单模态右偏灰度直方图后,通过多向加权策略构建出与原始图像灰度值紧密相关的加权Tsallis熵目标函数,并以该目标函数取最大值时对应的灰度值作为最终分割阈值.本文将提出的方法和3个阈值分割方法、1个软分割方法、1个活动轮廓分割方法以及1个自动聚类分割方法进行了比较.在4种不同模态情形下的4幅合成图像和50幅真实世界图像上的实验结果表明,本文提出的方法虽然在计算效率方面不占有优势,但它对不同模态的测试图像具有更稳健的分割适应性,且在量化分割精度所用的马修斯相关系数方面优于其他6个分割方法.

区域贸易政策不确定性、策略选择与中国多产品企业出口产品种类——基于中国-东盟《框架协议》的准自然实验

多产品企业产品种类调整有助于实现企业内资源优化配置。文章匹配2001—2013年中国工业企业数据、海关进出口产品数据与WITS关税数据,以中国-东盟《框架协议》签署作为准自然实验,通过双重差分的方法探究区域贸易政策不确定性对中国多产品企业出口产品种类的影响。实证结果表明,《框架协议》签署带来的区域贸易政策不确定性下降促使中国多产品企业显著增加出口产品种类,与Bernard et al.(2011)基于美加自由贸易区的研究结果形成了鲜明对比,主要原因在于东盟市场与北美市场的规模、产品结构等方面存在显著差异。此外,区域贸易政策不确定性下降对采取不同竞争策略的多产品企业出口种类的影响存在显著差异,采取质量竞争策略的多产品企业比采取数量竞争策略的多产品企业在《框架协议》签署的外生冲击下,增加更多的出口产品种类。此外,《框架协议》签署对区域贸易政策不确定性下降幅度更大的多产品企业出口产品种类的促进作用更加明显。进一步,《框架协议》签署带来的区域贸易政策不确定性下降对多产品企业出口产品种类增加的影响主要通过创新效应发生作用,而学习效应没有显著的作用。以上结论在稳健性检验中仍然成立。该研究为中国实施FTA战略、评估RCEP政策,以及理解中国制造业企业的出口多样化和企业内产品组合决策提供了新的视角。

汽车整车多级生产线协同排序优化方法

为满足汽车整车生产线不同工艺车间对车身序列的不同需求,提高汽车生产线多工艺车间的协同生产能力并降低生产成本,提出一种面向汽车整车多级生产线的协同排序优化方法。分析了汽车生产过程中不同工艺车间对车身序列的不同需求,在考虑焊接车间车型更换次数、涂装车间颜色更换次数、总装车间总超载和空闲时间、总装车间物料消耗均衡等传统优化目标的基础上,搭建了缓冲区重排序成本的目标函数,并以此构建了汽车整车多级生产线协同排序多目标优化模型,然后采用基于启发式出入站规则的第三代非支配排序遗传算法对模型进行优化求解。最后通过某公司的实际生产案例,验证了所提模型和方法的有效性。

面向流程制造的数字孪生车间可视化监控系统研究

为了解决流程制造过程监控实时性差、准确性不足的问题,在数字孪生技术迅速发展且与制造业结合愈发紧密的背景下,提出基于生产要素数据、生产工艺流程与多工序设备实体对象的数字孪生车间可视化监控系统架构。从要素、状态、运行逻辑等多个维度对多工序耦合生产线实体对象进行孪生建模,基于OPC UA统一架构的数据采集传输,虚拟车间的实时驱动等关键技术,实现了流程制造设备状态、生产要素工艺全流程三维可视化监控。基于某流程制造企业制丝生产试验线开展了应用验证,为提升流程制造过程中全生产要素的预见性、联动性、自治性提供了方法和实现途径。

碳交易如何影响绿色低碳发展?——基于多期DID与连续DID的经验研究

碳交易如何影响以绿色全要素生产率为核心指标的绿色低碳发展,需进行实证检验。基于2005—2019年中国省际面板数据,运用多期DID模型评估碳交易对绿色低碳发展的影响及其作用机制。结果表明:碳交易促进了试点地区绿色低碳发展,在经过安慰剂、PSM-DID、剔除用能权交易试点样本等一系列稳健性检验后,结论仍成立;碳交易实施对能源结构优化、产业结构升级与技术进步具有正向影响,绿色能源消费占比增加、高技术产业结构提升与技术进步是碳交易提高试点地区绿色低碳发展水平的主要机制。构建连续DID模型,研究碳交易规模对绿色低碳发展的影响,发现碳交易规模扩大对绿色低碳发展水平具有正向影响。研究结论为碳交易助力绿色低碳发展提供了经验支持,也为区域碳市场及全国统一碳市场的进一步扩容提供了有价值的启示。

以产业需求为导向的产教融合研究生培养模式探索与实践

为顺应社会经济高速发展对人才的迫切需求,促进人才培养供给侧和产业需求侧结构要素全方位融合,进一步优化产教融合人才培养模式,解决现阶段存在的校企合作不稳定、产学相对脱节、多主体协同机制不完善的问题,湖南大学控制科学与工程学科提出以产业需求为导向的“两翼支撑-三维协同-四链贯通”深度产教融合人才培养模式,以构建校内校外双实践平台为两翼支撑,完善学校、企业、政府三维协同机制,贯通产业链、教育链、实践链及人才链,将产教融合贯通产学研全过程,全面提升研究生的专业实践能力,在新时代高层次应用型工科人才的培养上取得显著的成效,实现研究生培养模式改革和产业迭代双统筹发展,可供国内外高校借鉴。

光致变色纱线在多层织物设计中的应用

为了丰富织物的多样性,利用光致变色纱线,结合表里换层双层组织,设计与开发了“P”字图案表里换层光致变色面料;并进一步设计与开发了上、中层表里换层结构的“E”字图案三层组织光致变色面料,实现了织物在光线照射下单面变色,而反面不显变色的特殊效果。将光致变色纱线与表里换层结构的双层或多层织物相结合,可以形成新型光致变色功能面料,为此类产品的开发与设计提供了一种新思路。

“多材料”+“多工艺”协同天府特色的设计课程实践与探索

为适应新的经济结构带来新的人才需求,解决产品设计专业重艺轻技的现象。课程在教学中融入四川传统工艺实践,以“多材料”“多工艺”、在实践中学习、知识迁徙等途径,培养学生立足实践、融会贯通的设计思维。在多元化的项目实践中,学生较好地掌握了综合材料的成型方法、装饰技法和工艺技巧,并在反复实践、再实践中体悟工艺的“程式”法则和匠心文化。本次教学改革为寻找地方传统工艺与现代设计教育的衔接方式,彰显设计教育的地域特征提供了一些教学设想和研究案例。

融合设备状态和产品要求的电解铜箔制造工艺参数优化

针对当前电解铜箔制造工艺参数的优化仅考虑产品要求的问题,提出了一种融合设备状态和产品要求的电解铜箔制造工艺参数优化方法。首先,为辨识铜箔制造中工艺、设备与产品参数之间的非线性关系,建立了基于神经网络的“工艺-设备”与产品参数的映射模型,并通过构建当前生产模式与历史生产模式的相似性度量方法,确定当前工艺参数的优化初始点;然后,基于所建立的映射模型、设备状态和产品要求构建多目标约束函数,并利用遗传算法优化工艺参数,获得同时满足设备状态和产品要求的最佳工艺参数。企业的生产验证表明:相较于仅考虑产品要求的工艺优化方法,所提方法优化后的工艺参数能在相同的设备状态下获得质量更好的产品,在常温/高温抗拉强度、常温/高温延伸率和树脂剥离强度这5项关键指标上,分别提升了6.1 MPa、6.1 MPa、1.9%、0.7%和0.22 N/mm,生箔制备和表面处理的生产效率也提高了2.65%和7.5%,能够有效保证并提高铜箔的质量和生产效益。

为什么国家严控撤县设区:基于粮食安全的新解释

撤县设区是我国推进新型城镇化建设的重要行政区划调整政策。但2021年以来,国家多次表态要严控撤县设区。将撤县设区政策视为准自然实验,基于2000—2019年县域经济社会数据,运用多期DID、PSM-DID、CMP模型、中介效应模型等分析了撤县设区政策对粮食生产和粮食安全的影响及作用机制,从粮食安全视角对国家严控撤县设区的合理性进行了论证。研究发现:首先,撤县设区政策不利于粮食生产和粮食安全,这一结论在更换回归模型、更换被解释变量、调整样本量等检验后仍然稳健,而且这种负面影响存在长期性;其次,撤县设区政策通过农业生产要素重新配置和“政府注意力”转移两个方面对粮食安全产生负面影响;最后,这种负面影响还存在地区异质性,撤县设区对非粮食生产核心区的负面影响更加显著,导致粮食安全责任进一步失衡。建议谨慎推进撤县设区,平衡不同省份粮食安全责任,有序推进县域粮食综合生产能力提升。

中国蛋鸡饲养绿色全要素生产率实证研究

为提高蛋鸡生产效率的同时减少污染排放,在考虑负向产出以及规模异质性和地区异质性的前提下,对蛋鸡养殖绿色全要素生产率(LHBG)进行测度。构建3层次SBM-MML指数,并将其分解为规模结构效率、技术效率以及管理效率。结果表明,2004-2018年平均LHBG为0.9967;大中小规模LHBG分别为0.9949、1.0013、0.9938;东中西部地区LHBG分别为0.9930、0.9980、1.0040。我国蛋鸡饲养绿色全要素生产率总体下降0.33%;规模上中规模最高、大规模其次、小规模最低;区域上西部最高,中部其次,东部最低;其分解效率表现为规模结构效率和技术效率提高,管理效率下降。