| 1. |
- Cao, Cejun, et al.
(författare)
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A fuzzy bi-level optimization model for multi-period post-disaster relief distribution in sustainable humanitarian supply chains
- 2021
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Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 235
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Tidskriftsartikel (refereegranskat)abstract
- In the aftermath of large-scale natural disasters, supply shortage and inequitable distribution cause various losses, hindering humanitarian supply chains? performance. The optimal decisions are difficult due to the complexity arising from the multi-period post-disaster consideration, uncertainty of supplies, hierarchal decision levels and conflicting objectives in sustainable humanitarian supply chains (SHSCs). This paper formulates the problem as a fuzzy tri-objective bi-level integer programming model to minimize the unmet demand rate, potential environmental risks, emergency costs on the upper level of decision hierarchy and maximize survivors? perceived satisfaction on the lower level of decision hierarchy. A hybrid global criterion method is devised to incorporate a primal-dual algorithm, expected value and branch-and-bound approach in solving the model. A case study using data from the Wenchuan earthquake is presented to evaluate the proposed model. Study results indicate that the hybrid global criterion method guides an optimal strategy for such a complex problem within a reasonable computational time. More attention should be attached to the environmental and economic sustainability aspects in SHSCs after golden rescue stage. The proposed bi-level optimization model has the advantages of reducing the total unmet demand rate, total potential environmental risks and total emergency costs. If the decision-agents with higher authorities act as the leaders with dominant power in SHSCs, the optimal decisions, respectively taking hierarchical and horizontal relationships into account would result in equal performance.
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| 2. |
- Chen, Xi, et al.
(författare)
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Technician routing and scheduling with employees’ learning through implicit cross-training strategy
- 2024
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Ingår i: International Journal of Production Economics. - 0925-5273 .- 1873-7579. ; 271
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Tidskriftsartikel (refereegranskat)abstract
- With record high talent shortages and skill mismatches around the world, this paper investigates a variant of multi-period dynamic technician and routing problem that can be modeled as a Markov decision process. To deal with the double tradeoffs between the routing and service time costs, as well as the current and future costs, we propose an approximate dynamic programming (ADP)-based cost function approximation (CFA) algorithm — the implicit cross-training strategy (ICT). A two-phase routing and scheduling heuristic is developed to account for both employees’ learning and future information, and to facilitate an efficient implementation of CFA. Extensive computational results show that ICT can provide a better solution in the current decision with a global view in comparison with the myopic strategy. In depth analysis demonstrates that ICT trains the workforce with more balanced skillsets and workloads, which ensures the flexibility of the workforce and helps buffer against the future uncertainties with substantial routing cost savings. Additionally, ICT has much more advantages in large-scale problems with more diversified service requests and randomly distributed customers.
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| 3. |
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| 4. |
- Ekström, Thomas, et al.
(författare)
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Towards a purchasing portfolio model for defence procurement – A Delphi study of Swedish defence authorities
- 2021
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Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 233
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Tidskriftsartikel (refereegranskat)abstract
- This study explains the constructs of a purchasing portfolio model (PPM) that defence authorities can use in practice in defence procurement and designs a segmentation model. We identify open PPM design and application questions in the literature and conduct a Delphi study with twenty experts from Swedish defence authorities to design a segmentation model that is fit-for-purpose. The paper addresses the open design and application questions discussed in the literature and satisfies the operational requirements of the Swedish Armed Forces (SwAF). The proposed segmentation model builds on three dimensions: the operational requirements of the SwAF, the market's ability to deliver supplies on time, and limitations in the SwAF operational capability if the market does not deliver supplies on time. To reduce complexity, we propose a two-stage model in which we use one dimension as a precursor to a two-dimensional model. In the latter, we merge sixteen elements into one square along with three other segments which users should treat differently. The paper contributes to extant academic knowledge on PPMs by eliciting practitioners' views on open design and application questions. We develop the proposed segmentation model in cooperation with practitioners and believe that it will be of value in defence procurement practice.
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| 5. |
- Grubbström, Robert W
(författare)
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On the net present value distribution affected by a random walk process
- 2022
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Ingår i: International Journal of Production Economics. - : ELSEVIER. - 0925-5273 .- 1873-7579. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we attempt to derive properties of the distribution of the net present value NPV, when the un-derlying cash flow is affected by stochastic disturbances in the form of a random walk process, the disturbances thus jumping continuously between each of two values. A leverage is introduced, affecting the size of each jump in relation to time.A given time period is split into a number of sub-periods of equal length. During each sub-period, a fraction of altogether one monetary unit is transferred. This cash flow is subject to the random walk, and is discounted by a given constant discount rate. We study consequences on the distribution of the net present value as the number of sub-periods increases beyond all bounds.Two different processes are studied, which turn out to have rather different properties. In the first, Case A, the two levels between each jump, are chosen as each others negative, and in the second, Case B, except for a timing factor, as each others inverse. Among other consequences, it is shown that the probability distribution of the NPV in Case A is close to, but different from, a lognormal distribution, and that in Case B, the NPV indeed has a lognormal distribution, but lies stable at a constant value. Also is shown that in Case A, the leverage must be at least 1/2 for a limiting distribution to exist, and in Case B at least unity. For leverage values above these values, respectively, the random walk will not affect NPV, and the net present value becomes deterministic.
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| 6. |
- Grubbström, Robert W., 1941-
(författare)
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Production decisions based on absolute vs. relative risk aversion and their extensions
- 2021
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Ingår i: International Journal of Production Economics. - : ELSEVIER. - 0925-5273 .- 1873-7579. ; 234
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we compare the two basic risk preference measures suggested independently by John W. Pratt (1964) and Kenneth J. Arrow (1965) as to their impact on simple production decisions with uncertain economic outcomes. We develop a further related concept by introducing a risk aversion leverage measuring the dependence of absolute risk aversion on wealth. We also discover a remarkable approximate relation between risk aversion measures of different leverages making the corresponding risk preference functions similar and leading to a method for estimating different Certainty Monetary Equivalents using zero-leverage expressions. We concentrate on three simple cases of production decisions of the Newsboy type.
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| 7. |
- Hagspiel, V., et al.
(författare)
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Capacity optimization of an innovating firm
- 2021
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Ingår i: International Journal of Production Economics. - : Elsevier B.V.. - 0925-5273 .- 1873-7579. ; 233
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Tidskriftsartikel (refereegranskat)abstract
- This article considers an incumbent's product innovation decision within an uncertain framework, where the firm decides whether to continue selling the established product. The model being dynamic allows to analyze the trade-off between an early innovation where the new product only slightly improves the existing one, or innovating late with a much better new product. We find that the effect of uncertainty is that it raises the value of the strategy where the firm keeps on producing the old product after innovating. This results in earlier investment if the firm stays active on the established product market after adopting the new product, and that it keeps on producing the established product for a longer time after the product innovation. Limited uncertainty could lead to a non-monotonicity: with a better new product it is not optimal to innovate, whereas innovating is optimal with a worse one. © 2021 The Authors
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| 8. |
- Jafari, Hamid, et al.
(författare)
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Postponement and logistics flexibility in retailing : The moderating role of logistics integration and demand uncertainty
- 2022
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Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 243
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic capabilities such as flexibility are considered influential in achieving superior performance, especially under uncertain circumstances. Among others, postponement is a well-established concept in operations and supply chain management (OSCM) and has been regarded as a key concept in managing supply and demand while increasing flexibility. This study investigates the effect of postponement on logistics flexibility, and that of the latter on retail firm performance. In addition, the moderating roles of logistics integration and demand uncertainty on these relationships are investigated. The study utilizes a quantitative survey and draws on a sample of 261 retailers in Sweden. Logistics flexibility proves to have a mediating role in the postponement–performance relationship. Furthermore, we provide support for the direct effect that postponement can have on logistics flexibility, and the subsequent effect of logistics flexibility on retail firm performance. We contribute by simultaneously studying postponement and logistics flexibility in the retailing context. We find conditional support for the moderating roles of logistics integration and demand uncertainty. The results show that for medium levels of uncertainty, the positive relationship between postponement and logistics flexibility, as well as logistics flexibility and firm performance, are intensified. From a practical standpoint, the findings underline that in the presence of high or low demand uncertainty, applying postponement may not always be beneficial in achieving logistics flexibility, and subsequently better performance. Moreover, if retailers prioritize logistics integration, they should not always expect superior performance gains from the flexibility benefits of postponement.
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| 9. |
- Kalaiarasan, Ravi, et al.
(författare)
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The ABCDE of supply chain visibility : A systematic literature review and framework
- 2022
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Ingår i: International Journal of Production Economics. - : Elsevier BV. - 0925-5273 .- 1873-7579. ; 248
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Forskningsöversikt (refereegranskat)abstract
- Supply chain visibility is a concept that is gaining increasing attention. Increasing levels of visibility in the supply chain is considered beneficial in many respects. A systematic literature review identified 47 empirical research papers from international scientific journals. Two main findings emerged from the content analysis. First, the perspectives provided in the extant literature can be grouped into four categories: antecedents, barriers and challenges, drivers, and effects. The effects include both capabilities and operational performance. Second, the few models on supply chain visibility include only antecedents and effects, and do not capture the perspectives of barriers, challenges, or drivers. We present a framework for supply chain visibility driven by insights from the content analysis. The ABCDE framework includes antecedents (A), barriers and challenges (BC), drivers (D), and effects (E), and provides a holistic view of supply chain visibility. The framework can aid managers with per-spectives and factors to consider when discussing, implementing, and improving supply chain visibility and provides researchers with a state-of-the-art review of supply chain visibility. We also propose an agenda for further research.
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| 10. |
- Kohtamäki, Marko, et al.
(författare)
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Exploring servitization through the paradox lens : Coping practices in servitization
- 2020
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Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 226
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Tidskriftsartikel (refereegranskat)abstract
- The study analyzes the coping practices that emerge when a manufacturer of standardized products and add-on services expands to provide customized solutions. Based on a comparative case study methodology conducted across four case companies, and an analysis of extensive documentary data, the study challenges the dichotomous ‘either-or thinking’ in servitization research and highlights ‘both-and thinking’ by identifying both paradoxes and coping practices. The study extends the literature by identifying four paradoxes in servitization: 1) effectiveness in the customization of solutions vs. efficiency in product manufacturing, 2) building a customer orientation vs. maintaining an engineering mindset, 3) organizing product and service integration vs. separated services and product organizations, and 4) exploratory innovation in solutions vs. exploitative innovation in product manufacturing. Moreover, the study identifies nine practices that manufacturing companies apply when coping with the paradoxical challenges that emerge during servitization. The findings may help manufacturing companies understand, accept, and address paradoxical challenges and balance tensions, as not all tensions can be resolved. The identification of these paradoxes allows us to understand the difficulties that manufacturing companies face during the servitization process and may help explain the servitization-deservitization trend among some manufacturing companies that some recent studies have identified.
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