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.

Study on Optimal Strategy of Grade Transition in Industrial Fluidized Bed Gas-Phase Polyethylene Production Process

A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables, such as polymerization temperature, the ratio of hydrogen to ethylene, the ratio of co-monomer to ethylene, feed rate of catalyst, and bed level. A new performance index, the ratio of melt flow (MFR), is included in the objective function, for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resin. It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product. This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system. The grade transition model is extended to a high space time yield (STY) process with the so-called condensed model operation. In the end, an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the basis of the optimal grade transition model. A sequential transition of six commercial polyethylene grades is illustrated for an optimal multi-product operation.

Efficient decomposition-based algorithm to solve long-term pipeline scheduling problem

This paper addresses the scheduling and inventory management of a straight pipeline system connecting a single refinery to multiple distribution centers.By increasing the number of batches and time periods,maintaining the model resolution by using linear programming-based methods and commercial solvers would be very time-consuming.In this paper,we make an attempt to utilize the problem structure and develop a decomposition-based algorithm capable of finding near-optimal solutions for large instances in a reasonable time.The algorithm starts with a relaxed version of the model and adds a family of cuts on the fly,so that a near-optimal solution is obtained within a few iterations.The idea behind the cut generation is based on the knowledge of the underlying problem structure.Computational experiments on a real-world data case and some randomly generated instances confirm the efficiency of the proposed algorithm in terms of the solution quality and time.

Improving Supply Chain Performance Through Supplier Selection and Order Allocation Problem

Suppliers play the vital role of ensuring the continuous supply of goods to themarket for businesses.If businesses do not maintain a strong bond with their suppliers,they may not be able to secure a steady supply of goods and products for their customers.As a result of failure to deliver products,the production and business activities of the business can be delayed which leads to the loss of customers.Normally,each trading enterprise will have a variety of commodity supply chains withmultiple suppliers.Suppliers play an important role and contribute to the value of the entire supply chain.Should any supplier encounters a problem,the whole supply chain of businesses will be affected and could lead to not guaranteeing the stable supply to the market.Thus,suppliers can be seen as a threat to businesses where they have the ability to increase input prices or decrease the quality of the required products and services they provide.The quantity of the business,and the supply lead time directly affect the operations and reduce the profitability of the business.The paper mainly focuses on the supplier selection problemunder a variety of price level and product families when using a two-phase fuzzy multi-objective linear programming.The objectives of the proposed model are to minimize the total purchasing and ordering cost in order to reduce the quantity of defective materials and the late-delivery components from suppliers.Moreover,the piecewise linear membership function is applied in themodel to determine an optimal solution which is based on the requirement of decision makers under their fuzzy environment.The results of this study can be applied in various business environment and provide a reliable decision tool for choosing potential suppliers relating to these objectives.Based on the results,the company canmake a good decision on supplier selection;therefore,the company can improve the quality and quantity of their final product.This is because,the best supplier can supply raw material using just-in-time application and reduce production risk on the manufacturing process.

Multi-Objective Production Planning Using Lexicographic Procedure

This paper presents a multi-objective production planning model for a factory operating under a multi-product, and multi-period environment using the lexicographic (pre-emptive) procedure. The model objectives are to maximize the profit, minimize the total cost, and maximize the Overall Service Level (OSL) of the customers. The system consists of three potential suppliers that serve the factory to serve three customers/distributors. The performance of the developed model is illustrated using a verification example. Discussion of the results proved the efficacy of the model. Also, the effect of the deviation percentages on the different objectives is discussed.

Is a Single Product Cost Function Appropriate for Institutions of Higher Education？ Empirical Evidence From China＇s Research Universities＊

Many studies exist in the literature of scale and scope economies in institutions of higher education employing multi-product cost functions of quadratic, constant elasticity substitution （CES）, or hybrid translog form. A single product cost function is normally considered inadequate and yield distorted results. Both quadratic and single product cost functions have been applied to university data from China＇s Ministry of Education （MOE）. This study compares those two methods and their statistical results and finds that ray economies of scale from these two cost functions are quite similar though the single product cost function which can not be used to calculate product-specific economies of scale or economies of scope.

Examining techno-economic interactions among fish species:A case of small-scale demersal fishery

Using the multi-product dual revenue function framework,this paper examines the nature and extent of technical and economic interactions among five demersal species of Al-Batinah demersal fishery,Oman during the 2010-2016 period.The parameters of the system of output supply functions are estimated using Zellner’s seemingly unrelated regressions(SUR)technique.The likelihood ratio test in relation to the structure of the multi-output production technology rejects the null-hypothesis of input-output separability and non-jointness in inputs.These results suggest that the underlying production technology is non-separable between the outputs and the quasi-fixed input,and the harvesting level of one species is likely to have spill-over economic effects on the harvesting levels of others.The own-price elasticities of output supply are found to be positive,inelastic,and statistically significant in four out of five cases suggesting that,other things being equal,fishers’supply decisions are influenced by the prevailing market prices of outputs.The estimated values of the cross-price elasticity of supply are negative,inelastic and statistically significant at the 5%level for eight output pairs.The calculated values of the Morishima elasticity of substitution(MES)indicate the presence of substitutability between ten output pairs.The cross-price elasticity estimates are in the range of0.001(between Emperor and Catfish)to0.275(between Seabream and Grouper)which is lower(in absolute value)than that of the MES estimates.The magnitudes of the cross-price elasticity and the MES estimates indicate the extent of spill-over effects of one species on the other and signal the extent of species targeting by fishers.A statistically significant spatial,seasonal,and inter-annual variability is observed in all species cases.Finally,the implications of the findings are discussed from the perspective of developing effective management approaches,achieving sustainability of fisheries resources and improving fishers’socio-economic conditions stipulated in the Five-Year development plans for the sector.

Foreign Demand,Competition Strategy,and Export Markups:Evidence from Chinese Multi-Product Exporters

Using Chinese microdata from 2000 to 2013,we document how demand shocks in export markets lead multi-product exporters to adjust markups across products.We find that,in response to positive demand shocks,quality-based competitive multi-product firms increase product markups significantly,particularly for core products,whereas cost-based competitive multi-product firms respond by reducing product markups.The reason for this is that positive foreign demand affects markups through two opposite channels:pro-innovative effects and pro-competitive ejfects.Pro-innovative effects are predominant among quality-based competitive multi-product firms,and these firms respond to positive foreign demand shocks by increasing product quality,prices,and markups.Pro-competitive ejfects are predominant among cost-based competitive multi-product firms,and these firms respond to positive foreign demand shocks by lowering product cost,prices,and markups.We demonstrate the presence of these mechanisms empirically.The results imply that firms with different competition strategies should adopt different measures in response to foreign demand shocks.

An integrated stochastic model and algorithm for multi-product newsvendor problems

In this paper,a multi-product newsvendor problem is formulated as a random nonlinear integrated optimization model by taking into consideration the selling price,the producing and outsourcing quantities,and the nonlinear budget constraint.Different from the existing models,the demands of products depend on the prices,as well as being timevarying due to random market fluctuation.In addition,outsourcing strategy is adopted to deal with possible shortage caused by the limited capacity.Consequently,the constructed model is involved with joint optimization of the producing and outsourcing quantities,and the selling prices of all the products.For this model with continuous random demands,we first transform it into a nonlinear programming problem by expectation method.Then,an efficient algorithm,called the feasible-direction-based spectral conjugate gradient algorithm,is developed to find a robust solution of the model.By case study and sensitivity analysis,some interesting conclusions are drawn as follows:(a)Budget is a critical constraint for optimizing the decision-making of the retailer,and there exist different threshold values of the budget for the substitute and complementarity scenarios.(b)The price sensitivity matrix seriously affects the maximal expected profit mainly through affecting the optimal outsourcing quantity.

Robot Application and Adjustment of Export Product Scope: Can We Have Both Efficiency and Quality?

Robot Application and Adjustment of Export Product Scope:Can We Have Both Efficiency and Quality?Jianhong Qi,Zhitong Zhang Based on the matching data of China Industrial Enterprise Database and China Customs Database from 2000 to 2015,this paper examines the infuence of robot application(RA)on the export product scope(EPS)of multi-product enterprises(MPEs),the influence channels,and the export competition strategies of these enterprises.The research results show that RA has promoted the expansion of EPS of MPEs,and this promotion effect is prominent especially for the export of laborintensive products,resource-intensive products and for non-state-owned enterprises(SOEs).The adjustment of EPS by RA not only enhances efficiency through productivity improvement effect and cost-saving effect,but also improves quality through emission-reduction effect and product quality effect,which is very obvious in long-quality-ladder enterprises.The RA-expanded product scope covers both old products and new products manufactured in the same industry.Facing fierce competition in the same industry,robot-using enterprises prefer quality competition strategy,which further promotes the expansion of EPS.

A study of the dynamical-fluctuation property inside jets in e^+e^-collisions

A study of the dynamical-fluctuation property of 2-jet events is carried out. It is found that the dynamical fluctuations of the hadronic system inside 2-jet events change with the variation of the cut parameter ycut. There is a transition point, where the dynamical fluctuations in these systems are circular in the transverse plane; and are elliptical in the longitudinal-transverse planes. It is shown that this transition point corresponds to the scale of visible jets. Meanwhile, the dynamical fluctuation properties inside a single-jet in 2-jet and 3-jet events are compared. The dynamical fluctuations inside quark- and gluon-jets are found to be qualitatively different. A scale for the 'visible gluon jet' production is thus obtained.

The Failure of Cooperative Farming Development Policies in Tōhoku,Japan

In the context of agricultural globalization, many national governments have instituted policies, such as cooperative farming, to help farmers improve their profitability, competitiveness, and the sustainability of their agricultural practices. This study focused on the Multi-Product Management Stabilization Plan developed in Japan in 2006, which aimed to adapt the agricultural practices in the country to globalization by focusing on cooperative farming, and assessed its effectiveness for developing and incorporating cooperative farming in the TShoku region in the 2000s. The results suggest that regional and prefectural agents experienced significant difficulties when attempting to develop cooperative farming. Although New Institutional Economics＇ theories suggest that these policies reflect the norms for developing agriculture more profitably and competitively, Japanese farmers did not regard the policies as relevant, practical, or sustainable, and they obstructed them.