| With the rapid development of social and economic,the problems of resource shortage and environmental pollution are getting worse,and remanufacturing has gradually become one of the most important ways to achieve the circular economy and implement the extend producer responsibility.Since the enhancement of consumer environmental awareness and formulation of many environmental policies(such as carbon emission policies and waste product recycling regulations,etc.),remanufacturing not only brings significant economic benefits,but also provides considerable environmental effects.Considering the driving factors of environmental policies,economic and environmental benefits,more and more manufacturers begin to carry on remanufacturing activities based on the original traditional production activities,thus the hybrid manufacturing/remanufacturing system is emerged.However,it is very difficult to apply traditional production planning tools to hybrid manufacturing/remanufacturing system directly because of two-way flow of the material and capital,more uncertainties or volatility factors,and close connection of material and capital flows between two subsystems,i.e.,manufacturing and remanufacturing,which are different from traditional manufacturing system.Therefore,based on integration and coordination of material and capital flows,it has a very important theoretical and practical value to study production decision problem of a hybrid manufacturing/remanufacturing system considering factors related to financial operations,which can improve resource utilization and overall production efficiency of manufacturing/remanufacturing enterprise;at the same time,it also has important academic and practical significances to study the effects of carbon emission constraint on manufacturing/remanufacturing decisions because carbon emission credit has become a significant factor in the production process of manufacturing enterprise.With operations research,financial analysis theory,non-linear optimization and uncertain optimization theories,this thesis first studies production planning in a hybrid manufacturing/remanufacturing system of a capital-constrained enterprise considering and not considering carbon emission constraint,and introduces the effect of the financing on total profit;then,based on integration of commercial credit,amortization strategy,capital cost and other factors related to financial operations,production decision problem of the hybrid manufacturing/remanufacturing system is studied in this paper.The main contents are as follows:Firstly,the research status of the following three aspects,i.e.,lot-sizing production planning of a hybrid manufacturing/remanufacturing system,manufacturing/remanufacturing decisions considering carbon emission constraints and related research on production operations integrated financial factors,are reviewed based on the research ideas and the framework of the whole paper;in order to provide a theoretical foundation for the following studies,the main processes and general characteristics of the hybrid manufacturing/remanufacturing system integrating or ignoring the capital flow are analyzed and the primary influence factors of production decisions in the hybrid system integrating financial operations are summarized.Secondly,considering the capital shortage problem that enterprises may encounter,especially for newly established or small and medium enterprises,the paper presents single-period stochastic models of manufacturing/remanufacturing planning issues in which a one-way substitution strategy is applied between new and remanufactured products,and synthesizes carbon emission constraint and financing planning to extend the original problem;then,the concavity of objective functions are proved,and some suitable methods(such as Kuhn-Tucker Conditions)are utilized to achieve optimal solutions based on different characteristics of each model;meantime,numerical examples are provided to explore the comparison results for the optimal manufacturing/remanufacturing decisions under different constraint conditions as well as to analyze the impacts of some parameters,such as the yield rate,recovery rate,initial capital,carbon cap and carbon price on production policies,total carbon emissions and expected profit,and to discuss the change trends of financing quantity and total profit of capital-constrained enterprise with the variance of recovery rate.The results of this study provide applicable suggestions to manufacturers and policy-makers.Thirdly,based on the consideration of commercial credits(including accounts receivable and accounts payable),short-term loan,current ratio and other factors related to financial operation,multi-period production decision optimization problem of a hybrid manufacturing/remanufacturing system is studied through combining a deterministic cash flow management model.First,two mixed integer programming models considering and not considering one-way substitution relationship between new and remanufactured products are formulated that maximize the terminal cash position equivalents and include the procurement cost and inventory cost of each input material,inventory cost of each product,manufacturing/remanufacturing cost and financing cost,etc.Then,the optimal solutions of the problem are obtained by using the standard branch and bound method and model solving software;in addition,we analyze the impacts of one-way substitution and different amortization plans on manufacturing/remanufacturing production decisions,satisfaction degree of product demands,corresponding short-term loan/amortization decisions and optimization objective,and discuss the effects of initial capital,credit terms(including accounts receivable and accounts payable)and other parameters on the strategies related to production and financial operations,cash flow balance,etc.Finally,both uncertainty and one-way substitution strategy of new and remanufactured products are considered,the mixed integer stochastic programming model based on scenario analysis is formulated integrating short-term loan,short-term investment,factoring of accounts receivable,prepayment of accounts payable,capital cost and other factors related to financial operations to study multi-period production decision optimization problem of a hybrid manufacturing/remanufacturing system that maximizes the economic value added.Then numerical examples are provided to analyze the effects of variance of the demands,minimum customer service level and other important parameters on total marginal profit and objective function,and to achieve the optimal working capital with the highest economic value added under different credit terms;at the same time,the results of this study show that the approach integrated financial operations proposed in this paper has obvious superiority in the decision-making processes and results than traditional approach.The innovations of this study are as follows:(1)With one-way substitution strategy between new and remanufactured products,on the one hand,single-period manufacturing/remanufacturing planning issues of a hybrid system are studied by introducing uncertain demand and carbon emission constraint;on the other hand,the paper extends comprehensive decisions of recycling/acquisition,and manufacturing/remanufacturing of a hybrid system to the multi-period and demand uncertainty case,which makes the research more realistic and more instructive to practical situation.(2)The capital condition is a key factor in whether the enterprise can achieve the optimal manufacturing/remanutacturing planning.Unlike the existing research,which assumes that the capital always sufficient,this paper takes into account the possible shortage of capital to study single-period manufacturing/remanufacturing planning issues of a hybrid system in which a one-way substitution strategy is applied between new and remanufactured products;in addition,considering the factors related to carbon emission,we further discuss the effects of the interaction between capital and carbon emission constraints on production quantities of two products,financing quantity and corresponding total profit,and the results of this paper are helpful for enterprises and policy makers to draw up reasonable strategies and policies.(3)The innovation is also embodied in studying the multi-period production decision problem of a hybrid manufacturing/remanufacturing system integrated considering the parameters,variables and constraint conditions related to financial operations from the overall optimization perspective.It is helpful to achieve the coordination of each process between manufacturing and remanufacturing systems,and the balance of material and capital flows in the whole hybrid system and so that improve the productivity of hybrid manufacturing enterprises. |
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