| 1. |
- Berling, Peter, et al.
(författare)
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Heuristic Coordination of Decentralized Inventory Systems Using Induced Backorder Costs
- 2006
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Ingår i: Production and operations management. - : Production and Operations Management Society, Baltimore, Md.. - 1059-1478 .- 1937-5956. ; 15:2, s. 294-311
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate a one-warehouse multiple-retailer system, where the inventory control decisions are coordinated using a near optimal induced backorder cost, β*. All installations use continuous review installation-stock (R, Q) policies. The analysis builds on an approximation model where the stochastic warehouse delays are replaced by their correct averages. The contributions include insights as to how β* is influenced by system parameters, and the determination of simple closed form β* estimates. The latter offering a practical means to achieve coordinated control of large size systems.
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| 2. |
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| 3. |
- Eliasson, Jonas, et al.
(författare)
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The Stockholm Congestion-Charging Trial 2006 : Overview of the effects
- 2009
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Ingår i: Transportation Research Part A. - Amsterdam : Elsevier BV. - 0965-8564 .- 1879-2375. ; 43:3, s. 240-250
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Tidskriftsartikel (refereegranskat)abstract
- The Stockholm congestion charging trial in 2006 demonstrated the effects of a full-scale time-differentiated urban road toll scheme. Improvements in travel times were large enough to be perceived by the general public. This was pivotal to the radical change of public attitudes that occurred during the trial and that resulted in a positive outcome of a subsequent referendum on a proposal for making the system permanent. This paper summarises the effects of the trial and analyses to what extent targets were met. Effects on congestion reduction were larger than anticipated, which also resulted in favourable economic and environmental effects. The trial showed that a single-cordon toll could affect traffic within a large area, i.e., not just close to the zone limits.
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| 4. |
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| 5. |
- Berling, Peter
(författare)
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Real options valuation principle in the multi-period base-stock problem
- 2008
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Ingår i: Omega. - : Elsevier BV. - 0305-0483 .- 1873-5274. ; 36:6, s. 1086-1095
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyzes the multi-period base-stock problem where there is a financial risk associated with a stochastic demand. For the single-period problem, it is known that the optimal inventory policy can be obtained with the Black and Scholes option pricing formula. This paper pushes the analysis further by applying the options valuation framework to the multi-period problem and presenting an algorithm for finding the optimal inventory policy. A computational study indicates that the effect of systematic risk is typically negligible (as for the single-period problem). Therefore, it can be concluded that systematic risk in demand is of little importance for optimal inventory control.
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| 6. |
- Hedenstierna, Philip, et al.
(författare)
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An Integrative Approach To Inventory Control
- 2009
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Ingår i: Rapid Modelling for Increasing Competitiveness. - London : Springer London. - 9781848827479 - 9781848827486 ; , s. 105-118
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Inventory control systems consist of three types of methods: forecasting, safety stock sizing and order timing and sizing. These are all part of the interpretation of a planning environment to generate replenishment orders, and may consequently affect the performance of a system. It is therefore essential to integrate these aspects into a complete inventory control process, to be able to evaluate different methods for certain environments as well as for predicting the overall performance of a system. In this research a framework of an integrated inventory control process has been developed, covering all relations from planning environment to performance measures. Based on this framework a simulation model has been constructed; the objective is to show how integrated inventory control systems perform in comparison to theoretical predictions as well as to show the benefits of using an integrated inventory control process when evaluating the appropriateness of inventory control solutions. Results indicate that only simple applications (for instance without forecasts or seasonality) correspond to theoretical cost and service level calculations, while more complex models (forecasts and changing demand patterns) show the need for tight synchronization between forecasts and reordering methods. As the framework describes all relations that affect performance, it simplifies the construction of simulation models and makes them accurate. Another benefit of the framework is that it may be used to transfer simulation models to real-world applications, or vice versa, without loss of functionality.
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| 7. |
- Hedenstierna, Philip, et al.
(författare)
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Design of a Framework for Inventory Control - Evaluation of Forecasting and Inventory Control Systems
- 2009
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Ingår i: Flexible Automation and Intelligent Manufacturing 2009 (FAIM 2009). - Middlesbrough, UK : Curran Associates, Inc.. - 9780956230331 - 9781615676279 ; , s. 573-580
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Konferensbidrag (refereegranskat)abstract
- Managing inventories so that overall costs are kept low, while service levels are maintained is the central issue of inventory control, which only regulates two things: the size and the timing of orders. This is typically executed through a planning method, such as the reorder point system or, less frequently, the periodic order quantity system. These take into account a forecast, supposed to gauge the average future demand, and a predetermined safety stock, buffering against forecast errors and demand uncertainty. Pure demand also influences the system, as transactions affect the inventory level. It is crucial to understand how a complete system of demand, forecasts, safety stock calculations and planning methods work together to measure service level and overall cost of the system. This paper outlines a framework for the unambiguous representation of the relations between methods that interpret environmental parameters to plan orders. A number of simulations based on the framework are run to show, how the integration of the inventory control functions may affect the overall performance of the system. The usefullness of the framework lies in its ability to make a system duplicable (i.e. to transfer an inventory control system to a simulation model, or vice versa). Not only is this property important for creating simulation models that exactly depict the system being analysed, it also enables the study of a complete system for order planning, as opposed to optimising individual methods. Studying an inclusive system allow the same metrics to be used to evaluate changes to any method in the system. Another benefit of this approach is that the system's metrics directly reflect changes in the environment. Simulations based on this framework are precise and substantially easier to evaluate than models not adhering to any standard.
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| 8. |
- Hilletofth, Per, et al.
(författare)
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Agent Based Decision Support in Manufacturing Supply Chain
- 2009
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Ingår i: Agent and Multi-Agent Systems: Technologies and Applications. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 3642016642 - 9783642016646 - 9783642016653 ; , s. 677-686
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Supply Chain Management (SCM) is becoming increasingly complex and an intensified competition in the end-markets has started to create a situation where co-operation requirements between companies in a Supply Chain (SC) are increasing. The old mechanistic operations management solutions are becoming obsolete and advanced decision support is increasingly needed to realize efficient and effective management of complex SCs. The objective of this research is to contribute to the understanding of how Agent Based Modeling (ABM) can advance decision making and to discuss why ABM should be regarded as method to realize Information Fusion (IF). In this research work an agent based model of SCM has been implemented in a simulation platform to provide an approach for evaluation of decision and management alternatives. Research shows that this kind of decision support system is based on IF, since it collects and fuses information from different sources into a situation image that provides effective support for human decision making
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| 9. |
- Hilletofth, Per, et al.
(författare)
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Demand chain management : a Swedish industrial case study
- 2009
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Ingår i: Industrial management & data systems. - : Emerald Group Publishing Limited. - 0263-5577 .- 1758-5783. ; 109:8-9, s. 1179-1196
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The purpose of this paper is to increase the understanding of demand chain management (DCM) by investigating how it has been structured and executed in an international manufacturing company. Design/methodology/approach - The main emphasis has been on producing descriptive results and the applied research strategy has been an embedded single case study. The case organization originates from Sweden, but it has significant international presence. Empirical data have been collected mainly from in-depth interviews with key persons representing senior management in the case company.Findings - This research shows that DCM is about developing synergies between the demand creation and the demand fulfillment processes. A completely implemented DCM approach should incorporate all the major demand creation and fulfillment processes. This kind of fully implemented approach probably does not exist in real life today but some companies have started to develop versions including some of the major processes, and this research provides an example of this. The ultimate goal of DCM is to gain competitive advantages by differentiating not only the products, but also the delivery process. This is necessary in markets characterized of intensive competition, high product variety, large amount of customer-adapted products, and short product life cycles. It can be concluded that DCM is not another name for demand driven supply chains (SCs) or a fad. It is rather a way to finally benefit from decade long marketing discussions on how to achieve customer focus. It highlights the interplay between marketing and supply chain management (SCM) as an enabler of value creation.Research limitations/implications - This research work is limited to one Swedish company; however the case company has large international presence and is in top three in their industry measured by sales, which provides some ground for the generalization of the research. Practical implications - This paper gives an insight for managers and practitioners to the value of coordinating marketing and SCM to develop a truly customer-driven organization and SC. Originality/value - Several studies have addressed the synergies between marketing and SCM but failed to address how to in some detail realize this in practice. This paper contributes by discussing how to realize this coordination in practice.
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| 10. |
- Hilletofth, Per, et al.
(författare)
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New Product Development in a Manufacturing Company - A Challenge for Supply Chain Management
- 2009
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Ingår i: Proceedings of the 19th International Conference on Flexible Automation and Intelligent Manufacturing. - : Teesside University. - 9780956230331 ; , s. 1169-1177
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Konferensbidrag (refereegranskat)abstract
- The last decades a new type of business environments has evolved characterized by rapid and volatile demand changes, short product life cycles, and high levels of customized products. The competitiveness of a business in these environments is mostly determined by its responsiveness. This is characterized by the ability to quickly scale up or down the production volume, the presence of an innovative and fast product development, and the quick incorporation of customer requirements into the product development. This paper employs a descriptive single case study approach to illustrate how product development is structured and executed in an international manufacturing company, seeking to realize an innovative, predictable, and efficient product development. The objective is to increase the understanding of how product development and product life-cycles are connected to Supply Chain Management (SCM). Case study findings reveal that the case company after implementing a strategic and structured Product Creation Process (PCP) has improved the efficiency and effectiveness of product development. Findings also reveal that the case company has not yet developed any linkages between product development and SCM. Still, the case company has become aware of this issue due to problems associated with the lack of integration between product development and SCM.
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