A Roman ${2}$-dominating function ($Rom2DF$) on a graph $G(V,E)$ is a function $g:V rightarrow {0,1,2}$ of $G$ such that for every vertex $xin V$ with $g(x)=0,$ either there exists a neighbor $y$ of $x$ with $g(y)=2$ or at least two neighbors, $u,v$ with $g(u)=g(v)=1$. The value $w(g)=sum_{xin V}g(x)$ is the weight of the Rom2DF. The minimum weight of a Rom2DF of $G$ is called the textit{Roman ${2}$-domination number} denoted by textit{$gamma_{{R2}}(G)$}. Since determining textit{$gamma_{{R2}}(G)$} of a graph $G$ is NP-hard and no metaheuristic algorithms have been proposed for the same, two procedures based on genetic algorithm are proposed as a solution for the Roman {2}-domination problem. One of the proposed methods employs a random initial population, while the other uses a population generated using heuristics. Experiments have been carried out on graphs generated using textit{Erdős–Rényi} model, a popular model for graph generation and $Harwell ;Boeing (HB)$ dataset. The experimental results demonstrate that both approaches provide a near optimal solution which is well within the known lower and upper bounds for the problem. The experimental results further show that the procedure based on random initial population has outperformed the heuristic based procedure.
{"title":"Metaheuristic Algorithms for Solving Roman {2}-Domination Problem","authors":"Alfred Raju M, Venkata Subba Reddy P","doi":"10.1051/ro/2024074","DOIUrl":"https://doi.org/10.1051/ro/2024074","url":null,"abstract":"A Roman ${2}$-dominating function ($Rom2DF$) on a graph $G(V,E)$ is a function $g:V rightarrow {0,1,2}$ of $G$ such that for every vertex $xin V$ with $g(x)=0,$ either there exists a neighbor $y$ of $x$ with $g(y)=2$ or at least two neighbors, $u,v$ with $g(u)=g(v)=1$. The value $w(g)=sum_{xin V}g(x)$ is the weight of the Rom2DF. The minimum weight of a Rom2DF of $G$ is called the textit{Roman ${2}$-domination number} denoted by textit{$gamma_{{R2}}(G)$}. Since determining textit{$gamma_{{R2}}(G)$} of a graph $G$ is NP-hard and no metaheuristic algorithms have been proposed for the same, two procedures based on genetic algorithm are proposed as a solution for the Roman {2}-domination problem. One of the proposed methods employs a random initial population, while the other uses a population generated using heuristics. Experiments have been carried out on graphs generated using textit{Erdős–Rényi} model, a popular model for graph generation and $Harwell ;Boeing (HB)$ dataset. The experimental results demonstrate that both approaches provide a near optimal solution which is well within the known lower and upper bounds for the problem. The experimental results further show that the procedure based on random initial population has outperformed the heuristic based procedure.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"119 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140380082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given a graph $G$, we consider the Italian domination number $gamma_I(G)$, the $2$-rainbow domination number $gamma_{r2}(G)$ and the Roman domination number $gamma_R(G)$. It is known that $gamma_I(G) leq gamma_{r2}(G) leq gamma_R(G)$ holds for any graph $G$. In this paper, we prove that $gamma_I(M(G)) =gamma_{r2}(M(G)) =gamma_R(M(G)) =n$ for the middle graph $M(G)$ of a graph $G$ of order $n$, which gives an answer for an open problem posed by Mustapha Chellali et al. [Discrete Applied Mathematics 204 (2016) 22--28]. Moreover, we give a complete characterization of Roman domination stable middle graphs, 2-rainbow domination stable middle graphs and Italian domination stable middle graphs.
{"title":"Italian, 2-rainbow and Roman domination numbers in middle graphs","authors":"Kijung Kim","doi":"10.1051/ro/2024072","DOIUrl":"https://doi.org/10.1051/ro/2024072","url":null,"abstract":"Given a graph $G$, we consider\u0000the Italian domination number $gamma_I(G)$,\u0000the $2$-rainbow domination number $gamma_{r2}(G)$ and\u0000the Roman domination number $gamma_R(G)$.\u0000It is known that $gamma_I(G) leq gamma_{r2}(G) leq gamma_R(G)$ holds for any graph $G$.\u0000In this paper, we prove that $gamma_I(M(G)) =gamma_{r2}(M(G)) =gamma_R(M(G)) =n$ for the middle graph $M(G)$ of a graph $G$ of order $n$, which gives an answer for an open problem posed by Mustapha Chellali et al. [Discrete Applied Mathematics 204 (2016) 22--28].\u0000Moreover, we give a complete characterization of Roman domination stable middle graphs, 2-rainbow domination stable middle graphs and Italian domination stable middle graphs.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140382173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improving logistics levels requires mobilizing more resources, resulting in more carbon emissions. We consider a manufacturer selling its products through an e-commerce platform that sells them to customers (reselling) or directly accessing customers via the platform by paying a proportional fee (agency selling). Under reselling, the manufacturer first sets a wholesale price and then the platform sets a retail price and a logistics level. Under agency selling, if using third-party logistics, the manufacturer sets the retail price and logistics level. When using the platform logistics, the manufacturer sets the retail price and the platform sets the logistics level; moreover, the manufacturer bears part of the logistics cost. This study examines the manufacturer's sales model and logistics selection and its impact on the platform's profit and consumer surplus. We find that if the logistics-improving efficiency is sufficiently high (low), the manufacturer should employ reselling (agency selling and third-party logistics) when the manufacturer bears a sufficient small or large part of the logistics cost. However, regardless of the size of the logistics-improving efficiency, the manufacturer should adopt agency selling and platform logistics when the logistics cost borne by the manufacturer is intermediate. If consumers become more sensitive to carbon emission levels, the manufacturer is less (more) likely to adopt the reselling model and platform logistics (agency selling model and platform logistics). Choosing reselling or agency selling and platform logistics, or agency selling and third-party logistics could benefit both the platform and consumers, generating a ``win-win-win" outcome.
{"title":"Sales model and logistics selections for a manufacturer considering carbon emission and logistics levels","authors":"Xiaojie Wu, Xin Liu, Xiaogang Lin","doi":"10.1051/ro/2024070","DOIUrl":"https://doi.org/10.1051/ro/2024070","url":null,"abstract":"Improving logistics levels requires mobilizing more resources, resulting in more carbon emissions. We consider a manufacturer selling its products through an e-commerce platform that sells them to customers (reselling) or directly accessing customers via the platform by paying a proportional fee (agency selling). Under reselling, the manufacturer first sets a wholesale price and then the platform sets a retail price and a logistics level. Under agency selling, if using third-party logistics, the manufacturer sets the retail price and logistics level. When using the platform logistics, the manufacturer sets the retail price and the platform sets the logistics level; moreover, the manufacturer bears part of the logistics cost. This study examines the manufacturer's sales model and logistics selection and its impact on the platform's profit and consumer surplus. We find that if the logistics-improving efficiency is sufficiently high (low), the manufacturer should employ reselling (agency selling and third-party logistics) when the manufacturer bears a sufficient small or large part of the logistics cost. However, regardless of the size of the logistics-improving efficiency, the manufacturer should adopt agency selling and platform logistics when the logistics cost borne by the manufacturer is intermediate. If consumers become more sensitive to carbon emission levels, the manufacturer is less (more) likely to adopt the reselling model and platform logistics (agency selling model and platform logistics). Choosing reselling or agency selling and platform logistics, or agency selling and third-party logistics could benefit both the platform and consumers, generating a ``win-win-win\" outcome.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140228987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bin Yue, Jie Yang, Junxu Ma, Jinfa Shi, Linjian Shangguan
The vehicle routing problem (VRP) is a well-researched problem in the operations research literature. This paper studies a vehicle routing problem with time windows. Based on Solomon’s re-search, an improved sequential initialization algorithm, Solomon i1 with DTWC (Solomon i1 with Dynamic Time Windows Compatibility), is proposed in this paper to construct feasible initial solutions with higher quality in less calculation time. A tabu search with VNS (Variable Neighborhood Search) and the Metropolis criterion is used to further optimize the solutions that the proposed initialization algorithm provides. We run computational experiments on cases of well-known problems. Results show that compared to the initialization method before the change, our improved initialization approach performs well in terms of providing a better feasible initialization solution in less time, with an average 10 % improvement in solution quality and an average 34 % computational time savings. The proposed initialization algorithm’s superiority is also demonstrated by the tabu search’s better performance on the initial solutions it produces.
{"title":"An improved sequential insertion initialization algorithm and Tabu search to vehicle routing problem with time windows","authors":"Bin Yue, Jie Yang, Junxu Ma, Jinfa Shi, Linjian Shangguan","doi":"10.1051/ro/2024069","DOIUrl":"https://doi.org/10.1051/ro/2024069","url":null,"abstract":"The vehicle routing problem (VRP) is a well-researched problem in the operations research literature. This paper studies a vehicle routing problem with time windows. Based on Solomon’s re-search, an improved sequential initialization algorithm, Solomon i1 with DTWC (Solomon i1 with Dynamic Time Windows Compatibility), is proposed in this paper to construct feasible initial solutions with higher quality in less calculation time. A tabu search with VNS (Variable Neighborhood Search) and the Metropolis criterion is used to further optimize the solutions that the proposed initialization algorithm provides. We run computational experiments on cases of well-known problems. Results show that compared to the initialization method before the change, our improved initialization approach performs well in terms of providing a better feasible initialization solution in less time, with an average 10 % improvement in solution quality and an average 34 % computational time savings. The proposed initialization algorithm’s superiority is also demonstrated by the tabu search’s better performance on the initial solutions it produces.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"31 5‐6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140228131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Zatesko, Renato Carmo, André L. P. Guedes, Raphael C. S. Machado, Celina M. H. Figueiredo
Abstract. An r-graph is an r-regular graph G on an even number of vertices where every odd set X ⊆V(G) is connected by at least r edges to its complement V(G) X. Every r-graph has a perfect matching and in a poorly matchable r-graph every pair of perfect matchings intersect, which implies that poorly matchable r-graphs are not r-edge-colourable. We prove, for each fixed r ≥ 3, that poorly matchable r-graph recognition is coNP-complete, an indication that, for each odd d ≥ 3, it may be a hard problem to recognise d-regular (d−1)-edge-connected non-d-edge-colourable graphs, referred to as d-snarks in this paper. We show how to construct, for every fixed odd d ≥ 5, an infinite family of d-snarks. These families provide a natural extension to the well-known Loupekine snarks. We also discuss how the hunting of the smallest d-snarks may help in strengthening and better understanding the major Overfull Conjecture on edge-colouring simple graphs.
摘要r图是偶数顶点上的r正则图G，其中每个奇数集X⊆V(G)至少有r条边与其补集V(G) X相连。每个r图都有一个完美匹配，而在一个差匹配r图中，每一对完美匹配都相交，这意味着差匹配r图不是r-edge-colourable。我们证明，对于每个固定的 r ≥ 3，可差匹配 r 图的识别是 coNP-complete，这表明对于每个奇数 d ≥ 3，识别 d-regular (d-1)-edge-connected non-d-edge-colourable graphs（本文中称为 d-snarks）可能是一个难题。我们展示了如何为每一个固定奇数 d ≥ 5 构建一个无穷的 d-snarks 族。这些族是对著名的卢佩金星形的自然扩展。我们还讨论了寻找最小 d-snarks 如何有助于加强和更好地理解关于边着色简单图的主要 Overfull 猜想。
{"title":"The hardness of recognising poorly matchable graphs and the hunting of the d-snark","authors":"L. Zatesko, Renato Carmo, André L. P. Guedes, Raphael C. S. Machado, Celina M. H. Figueiredo","doi":"10.1051/ro/2024068","DOIUrl":"https://doi.org/10.1051/ro/2024068","url":null,"abstract":"Abstract. An r-graph is an r-regular graph G on an even number of vertices where every odd set X ⊆V(G) is connected by at least r edges to its complement V(G) X. Every r-graph has a perfect matching and in a poorly matchable r-graph every pair of perfect matchings intersect, which implies that poorly matchable r-graphs are not r-edge-colourable. We prove, for each fixed r ≥ 3, that poorly matchable r-graph recognition is coNP-complete, an indication that, for each odd d ≥ 3, it may be a hard problem to recognise d-regular (d−1)-edge-connected non-d-edge-colourable graphs, referred to as d-snarks in this paper. We show how to construct, for every fixed odd d ≥ 5, an infinite family of d-snarks. These families provide a natural extension to the well-known Loupekine snarks. We also discuss how the hunting of the smallest d-snarks may help in strengthening and better understanding the major Overfull Conjecture on edge-colouring simple graphs.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"228 4‐6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140233429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A sustainable manufacturing-remanufacturing inventory model with two production phases is presented in this study. In this two phases model, the first phase is used for manufacturing whereas the second phase is used for both manufacturing and remanufacturing. Keeping in mind about environment and price of products, it is presumed that market demand rate is influenced by the greenness of item and unit selling price simultaneously. Remanufacturing is performed for non-serviceable items i.e., defective items which are produced from imperfect production and used items that are purchased from the market. But the products for which remanufacturing cost is more than manufacturing cost are scraped off. In the production process carbon releases from setting up, manufacture and holding of the perfect items. To mitigate the carbon emission carbon tax regulation is imposed. Next, concavity of the profit function is driven through the pseudo concavity. Profit is maximized by minimizing the economic, environmental, and social effect. The models are illustrated by a numerical example and a sensitivity analysis is also elaborated for fixed parameters. Special cases are provided to compare the result with previous literature. The results shows that manufacturer wishes to engage in remanufacturing as remanufacturing cost continuously increases with respect time. Another important finding is that the manufacturer can choose remanufacturing as the cost is lower than manufacturing for saving environment. Finally, mathematical findings are listed and managerial implications are recorded.
{"title":"A sustainable manufacturing-remanufacturing inventory model with price and green sensitive demand for defective and usable items","authors":"Rakibul Haque, Magfura Pervin, Sankar Prasad Mondal","doi":"10.1051/ro/2024067","DOIUrl":"https://doi.org/10.1051/ro/2024067","url":null,"abstract":"A sustainable manufacturing-remanufacturing inventory model with two production phases is presented in this study. In this two phases model, the first phase is used for manufacturing whereas the second phase is used for both manufacturing and remanufacturing. Keeping in mind about environment and price of products, it is presumed that market demand rate is influenced by the greenness of item and unit selling price simultaneously. Remanufacturing is performed for non-serviceable items i.e., defective items which are produced from imperfect production and used items that are purchased from the market. But the products for which remanufacturing cost is more than manufacturing cost are scraped off. In the production process carbon releases from setting up, manufacture and holding of the perfect items. To mitigate the carbon emission carbon tax regulation is imposed. Next, concavity of the profit function is driven through the pseudo concavity. Profit is maximized by minimizing the economic, environmental, and social effect. The models are illustrated by a numerical example and a sensitivity analysis is also elaborated for fixed parameters. Special cases are provided to compare the result with previous literature. The results shows that manufacturer wishes to engage in remanufacturing as remanufacturing cost continuously increases with respect time. Another important finding is that the manufacturer can choose remanufacturing as the cost is lower than manufacturing for saving environment. Finally, mathematical findings are listed and managerial implications are recorded.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"37 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140249905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, live streaming is becoming a popular channel to sell products all over the world. Compared to traditional e-commerce channel, live streaming channel may not only bring consumers more shopping convenience, but also pose consumers more privacy concern. This paper considers a supply chain consisting of a manufacturer and an e-tailer who sells through dual channels (i.e., live streaming and traditional e-commerce) to explore how shopping convenience and privacy concern affect the optimal decisions. We build game models of two pricing (exogenous and endogenous) and two incentive contracts (wholesale price and two-part tariff). We find that the optimal promotion efforts are decreasing in shopping convenience while increasing in privacy concerns under the wholesale price contract, and independent of them under the two-part tariff contract when pricing is not a decision (such as iPhone); the optimal promotion efforts are increasing in shopping convenience while decreasing in privacy concern when pricing is a decision (such as the seasonal products). Whether the retail pricing is a decision or not, supply chain coordination can be achieved by the two-part tariff contract, but not through the wholesale price contract. Further, the two-part tariff contract is more favorable to the manufacturer if the exogenously given retail price is low, and the wholesale price contract is more favorable to the manufacturer if the retail price is high; the two-part tariff contract is always more beneficial for the supply chain than the wholesale price contract. Finally, we extend our analysis to relax a more realistic form with a variable effort elasticity and verify the robustness of the theoretical results.
{"title":"Dual channel sales in supply chain: live streaming or traditional e-commerce","authors":"Xuejun Zhou, Zhibing Liu, Jie Liu, Chen Pan","doi":"10.1051/ro/2024066","DOIUrl":"https://doi.org/10.1051/ro/2024066","url":null,"abstract":"In recent years, live streaming is becoming a popular channel to sell products all over the world. Compared to traditional e-commerce channel, live streaming channel may not only bring consumers more shopping convenience, but also pose consumers more privacy concern. This paper considers a supply chain consisting of a manufacturer and an e-tailer who sells through dual channels (i.e., live streaming and traditional e-commerce) to explore how shopping convenience and privacy concern affect the optimal decisions. We build game models of two pricing (exogenous and endogenous) and two incentive contracts (wholesale price and two-part tariff).\u0000We find that the optimal promotion efforts are decreasing in shopping convenience while increasing in privacy concerns under the wholesale price contract, and independent of them under the two-part tariff contract when pricing is not a decision (such as iPhone); the optimal promotion efforts are increasing in shopping convenience while decreasing in privacy concern when pricing is a decision (such as the seasonal products). Whether the retail pricing is a decision or not, supply chain coordination can be achieved by the two-part tariff contract, but not through the wholesale price contract. Further, the two-part tariff contract is more favorable to the manufacturer if the exogenously given retail price is low, and the wholesale price contract is more favorable to the manufacturer if the retail price is high; the two-part tariff contract is always more beneficial for the supply chain than the wholesale price contract. Finally, we extend our analysis to relax a more realistic form with a variable effort elasticity and verify the robustness of the theoretical results.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"42 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140250156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given the problem of minimizing a possibly nonconvex and nonsmooth function in a real Hilbert space, we present a generalized $epsilon$-descent algorithm motivated from the abstract descent method introduced by Attouch et al.(2013} with two essential addition, we consider scalar errors on the sufficient descent condition, as well as, on the relative inexact optimality condition. Under general conditions on the function to be minimized, we obtain that all the accumulation points of the sequences generated by the algorithm, if they exist, are generalized critical limit points of the objective function.
{"title":"Abstract generalized epsilon-descent algorithm","authors":"Estéfany Castillo Ventura, Erik ALEX PAPA QUIROZ","doi":"10.1051/ro/2024060","DOIUrl":"https://doi.org/10.1051/ro/2024060","url":null,"abstract":"Given the problem of minimizing a possibly nonconvex and nonsmooth function in a real Hilbert space, we present a generalized $epsilon$-descent algorithm motivated from the abstract descent method introduced by Attouch et al.(2013} with two essential addition, we consider scalar errors on the sufficient descent condition, as well as, on the relative\u0000inexact optimality condition. Under general conditions on the function to be minimized, we obtain that all the accumulation points of the sequences generated by the algorithm, if they exist, are generalized critical limit points of the objective function.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"49 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140077145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The space industry is known as an important driver for many world economies. In Iran, the acquisition of satellite technology knowledge is one of the achievements of the country's scientific and technological indicators in the recent years, but the position and importance of optimal investment in this industry has been not considered, effectively. The optimal technology portfolio is one of the tools that can cover this gap and lead to better decision making by policy makers. In this paper, the optimum technology portfolio determination regarding its goals, attributes and challenges is addressed for Iran space industry with a hybrid quantitative-qualitative method in two short and medium term periods. We formulate a technology portfolio selection model with these multi-objectives functions: maximization of benefits in using different technologies comprising of both short and medium term portfolios, maximizing the total summation of all technology readiness levels (TRLs), maximizing the acquisition speed for the technologies, and minimizing the acquisition risk of technologies in each portfolio. In the proposed model, the usability, acquisition cost, and complexity of each technology are considered, meticulously. Also, the goal programming method is used to integrate the objective functions. Another novelty of this paper is formulation of two portfolios with two different time periods which their corresponding inputs and outputs affect each other’s. This research can significantly help in directing the country’s investment in the space industry, spatial ecosystem orientation, facilitating the creation of space-based businesses, improving economic growth, also provides guidelines to improve the related policies in this area. In addition, it can be considered as an inspiration for other developing countries in the space industry.
{"title":"Hybrid quantitative-qualitative method for technology portfolio selection: A case study of Iran space industry","authors":"Emad Chizari, Seyed Hassan Sedighy, Mirsaman Pishvaee, Adel Azar","doi":"10.1051/ro/2024055","DOIUrl":"https://doi.org/10.1051/ro/2024055","url":null,"abstract":"The space industry is known as an important driver for many world economies. In Iran, the acquisition of satellite technology knowledge is one of the achievements of the country's scientific and technological indicators in the recent years, but the position and importance of optimal investment in this industry has been not considered, effectively. The optimal technology portfolio is one of the tools that can cover this gap and lead to better decision making by policy makers. In this paper, the optimum technology portfolio determination regarding its goals, attributes and challenges is addressed for Iran space industry with a hybrid quantitative-qualitative method in two short and medium term periods. We formulate a technology portfolio selection model with these multi-objectives functions: maximization of benefits in using different technologies comprising of both short and medium term portfolios, maximizing the total summation of all technology readiness levels (TRLs), maximizing the acquisition speed for the technologies, and minimizing the acquisition risk of technologies in each portfolio. In the proposed model, the usability, acquisition cost, and complexity of each technology are considered, meticulously. Also, the goal programming method is used to integrate the objective functions. Another novelty of this paper is formulation of two portfolios with two different time periods which their corresponding inputs and outputs affect each other’s. This research can significantly help in directing the country’s investment in the space industry, spatial ecosystem orientation, facilitating the creation of space-based businesses, improving economic growth, also provides guidelines to improve the related policies in this area. In addition, it can be considered as an inspiration for other developing countries in the space industry.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"41 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140259155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have observed from practice that both the upstream and downstream firms in sustainable supply chain are motivated to invest in green design to create new economic and environmental values. Channel leadership as an important factor affecting the channel profit distribution will reshape the investment motivation of enterprises. In this paper, we construct six kinds of pricing and green design decision models to explore the optimal green design strategies for sustainable supply chain consisting of one manufacturer and one retailer under different channel leadership, and investigate the interaction between channel leadership and green design strategy, and their impact on sustainable supply chain performance, environment and consumer surplus. We find that regardless of the channel leadership, the wholesale and retail prices of products under different green design strategies are always affected by the cost effect of green design. In terms of boosting the green design level and market demand, increasing the consumer surplus and enterprises profits, only when the manufacturer is the channel leader and the green design cost effect is small, the retailer can implement green design better. Moreover, when the manufacturer implements green design, the better channel structure between the retailer-led and Nash equilibrium game depends on the green design cost effect, but both are better than the manufacturer-led. However, when the retailer implements green design, the channel structure of Nash equilibrium game is always better. We finally illustrate that under different channel leadership, which green design strategy is more conducive to reducing the total environment impact of products depends on the joint effect of green design cost effect and green design environment effect.
{"title":"Green design strategies for sustainable supply chain considering channel leadership","authors":"Fengmin Yao, Yingluo Yan, Likun Liu, Jiayi Sun","doi":"10.1051/ro/2024056","DOIUrl":"https://doi.org/10.1051/ro/2024056","url":null,"abstract":"We have observed from practice that both the upstream and downstream firms in sustainable supply chain are motivated to invest in green design to create new economic and environmental values. Channel leadership as an important factor affecting the channel profit distribution will reshape the investment motivation of enterprises. In this paper, we construct six kinds of pricing and green design decision models to explore the optimal green design strategies for sustainable supply chain consisting of one manufacturer and one retailer under different channel leadership, and investigate the interaction between channel leadership and green design strategy, and their impact on sustainable supply chain performance, environment and consumer surplus. We find that regardless of the channel leadership, the wholesale and retail prices of products under different green design strategies are always affected by the cost effect of green design. In terms of boosting the green design level and market demand, increasing the consumer surplus and enterprises profits, only when the manufacturer is the channel leader and the green design cost effect is small, the retailer can implement green design better. Moreover, when the manufacturer implements green design, the better channel structure between the retailer-led and Nash equilibrium game depends on the green design cost effect, but both are better than the manufacturer-led. However, when the retailer implements green design, the channel structure of Nash equilibrium game is always better. We finally illustrate that under different channel leadership, which green design strategy is more conducive to reducing the total environment impact of products depends on the joint effect of green design cost effect and green design environment effect.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140258405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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