Rainer Kleber | Otto-von-Guericke-University Magdeburg (original) (raw)

Papers by Rainer Kleber

Research paper thumbnail of Optimal control of a one product recovery system with backlogging

... AND STEFAN MINNER AND RAINER KLEBER Faculty of Economics and Management, Otto-von-Guericke-Un... more ... AND STEFAN MINNER AND RAINER KLEBER Faculty of Economics and Management, Otto-von-Guericke-University Magdeburg, PO Box 4120, D-39016 Magdeburg, Germany In this paper a product recovery system for one product is investigated. ...

Research paper thumbnail of Modellgestützte Flexibilitätsanalyse von Strategien zur Ersatzteilversorgung in der Nachserienphase

Das Bestandsmanagement von Ersatzteilen stellt Hersteller langlebiger Industrie- und Konsumgüter ... more Das Bestandsmanagement von Ersatzteilen stellt Hersteller langlebiger Industrie- und Konsumgüter insbesondere in der Nachserienphase vor große Herausforderungen, da nach Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibilität nur noch in eingeschränktem Maße vorhanden ist. In diesem Beitrag werden Strategien, bestehend aus Kombinationen der am häufigsten genutzten Beschaffungsoptionen in Form von Abschlusslosbildung zu Serienbedingungen, Nachproduktion in kleineren Losen und

Research paper thumbnail of An Advanced Heuristic for Multiple-Option Spare Parts Procurement after End-of-Production

After-sales service is a major profit generator for more and more OEMs in industries with durable... more After-sales service is a major profit generator for more and more OEMs in industries with durable products. Successful engagement in after-sales service improves customer loyalty and allows for competitive differentiation through superior service like an extended service period after end of production during which customers are guaranteed to be provided with service parts. In order to fulfill the service guarantee

Research paper thumbnail of Reverse logistics in a pharmaceutical company: a case study

Schering spends considerable effort to undertake product recovery activities in pharmaceutical pr... more Schering spends considerable effort to undertake product recovery activities in pharmaceutical production. The two main recovery activities are by-product recycling and solvent reuse. The main driver for engaging in these activities is economical. Recovery leads to annual savings of approximately DM 25 million, which is about 8.5 % of the total production cost. This figure does not include additional savings

Research paper thumbnail of Simultane Maschinenbelegungs- und Personaleinsatzplanung in KMUs anhand eines Fallbeispiels aus der Druckereibranche

In dem vorliegenden Beitrag zur Produktionslogistik wird die auftragsorientierte Fertigung von Dr... more In dem vorliegenden Beitrag zur Produktionslogistik wird die auftragsorientierte Fertigung von Druckaufträgen in der maschinellen Werkstattproduktion klein- und mittelständischer Unternehmen (KMU) am Fallbeispiel einer Akzidenzdruckerei betrachtet. Wesentliche Planungsaufgaben stellen dabei die Maschinenbelegungs- und die Personaleinsatzplanung mit der Qualifikation der Mitarbeiter als verbindendem Element dar. In der Literatur und der praktischen Anwendung werden die Teilprobleme weitgehend getrennt voneinander betrachtet und häufig

Research paper thumbnail of On how the acquisition of recoverable parts influences the profitability of spare parts management for durables

In the management of spare parts for durables OEMs often face a sharp decline in sales of spare p... more In the management of spare parts for durables OEMs often face a sharp decline in sales of spare parts when the warranty period of their products ends. One reason for this effect is given by the high profitability of the after sales market which attracts competitors. If the competitors’ main sourcing option consists of repairing used or broken parts, an

Research paper thumbnail of On how buyback and remanufacturing strategies affect the profitability of spare parts supply chains

The purpose of this paper is to provide a case-based framework to offer insights on the opportuni... more The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage spare parts supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they themselves repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control over demand which might be obtained by offering buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is the provision of a simple deterministic framework for answering the question whether a buyback option should be offered by the OEM to the repair shops, and which buyback price should be paid for each returned core. We further highlight the impact of remanufacturing performed at the OEM on the profitability of buyback.

Research paper thumbnail of The Effect of Material Price and Product Demand Correlations on Combined Sourcing and Inventory Management

Both material sourcing and inventory management are important competitiveness factors, and it is ... more Both material sourcing and inventory management are important competitiveness factors, and it is a significant challenge to integrate the two areas. In sourcing, combined strategies using long-term contracts and the spot market received increasing attention recently, typically concentrating on the financial effects. However, there is limited research on the consequence of combined sourcing considering both purchasing and inventory effects from an operations point of view. In this paper, we analyze the effect of uncertainty on the combined sourcing decision under stochastic demand and random spot-market-price fluctuations and exploit the benefits of forward buying in periods with low spot-price realizations, but also of intended backordering in case of a high spot price. Since the decision on capacity reservation has to take into account the short-term utilization of each source which in turn depends on the available long-term contract capacity, decision making faces highly complex interactions between long-term and short-term decisions.

Research paper thumbnail of A Heuristic Approach for Integrating Product Recovery into Post PLC Spare Parts Procurement

ABSTRACT Product recovery gains increasing importance in spare parts acquisition, especially duri... more ABSTRACT Product recovery gains increasing importance in spare parts acquisition, especially during the post product-life-cycle (PLC) service period. Considering product recovery in addition to traditional procurement options (final order, extra production) makes the underlying stochastic dynamic planning problem highly complex. An efficient heuristic for solving the integrated procurement problem is developed, which can be used to exploit the exibility offered by product recovery.

Research paper thumbnail of Reverse logistics in a pharmaceutical company: the Schering case

Managing Closed-Loop Supply Chains, 2005

Research paper thumbnail of Managing Dynamic Product Recovery: An Optimal Control Perspective

Research paper thumbnail of Modellgestützte Flexibilitätsanalyse von Strategien zur Ersatzteilversorgung in der Nachserienphase

Zeitschrift für Betriebswirtschaft, 2009

Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibili... more Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibilität nur noch in eingeschränktem Maße vorhanden ist. In diesem Beitrag werden Strategien, bestehend aus Kombinationen der am häufigsten genutzten Beschaffungsoptionen in Form von Abschlusslosbildung zu Serienbedingungen, Nachproduktion in kleineren Losen und Aufarbeitung von Altprodukten anhand eines mathematischen Planungsmodells bezüglich ihrer Flexibilitätseigenschaften untersucht. Unter praxisnahen Rahmenbedingungen zeigt sich, dass sowohl Nachproduktion als auch Aufarbeitung als Versorgungsoption -insbesondere aufgrund der ihnen innewohnenden Zeitflexibilität -eine hohe Kostenersparnis gegenüber einer reinen Abschlusslosbevorratung gewährleisten können, selbst wenn deren Stückkosten weitüber denjenigen der Serienproduktion liegen. Weiter stellt sich heraus, dass die Nachproduktion das größte Flexibilitätspotenzial besitzt, soweit es nicht durch Vorgabe von Mindestproduktionsmengen zu stark eingeschränkt wird. Die aufgrund ihrer Abhängigkeit vom Altproduktrückfluss aus Flexibilitätssicht eigentlich weniger attraktive Aufarbeitung kann der Nachproduktion im Endeffekt jedochüberlegen sein, sofern ihr Stückkostenvorteil hinreichend hoch ist. Schließlich ergibt sich, dass eine kombinierte Nutzung beider Versorgungsoptionen in der Nachserienphase in der Regel nur noch einen vergleichsweise geringen zusätzlichen Erfolgsbeitrag liefert.

Research paper thumbnail of Optimal control of production and remanufacturing in a simple recovery model with linear cost functions

OR Spektrum, 2001

In this paper, a recovery system for perishable items is introduced and developed considering pro... more In this paper, a recovery system for perishable items is introduced and developed considering production and remanufacturing capacity constraints. The system consists of two inventories, one for serviceable items and the other for returned and recoverable items. Taking the production cost, remanufacturing cost, disposal cost, and the loss caused by deterioration into account, the optimal control model is established to minimise the total cost. The continuous-time dynamic optimal production, remanufacturing and disposal rates that minimise the total cost are obtained using Pontryagin's maximum principle. Additionally, to highlight the advantage of the dynamic optimal policy, the case of the static optimal policy that does not vary with time is investigated and compared with the dynamic policy. It is shown that the dynamic optimal policy is significantly better than the static optimal policy. A numerical example is provided to illustrate the proposed methods.

Research paper thumbnail of Dynamic buy-back for product recovery in end-of-life spare parts procurement

International Journal of Production Research, 2012

The efficient supply of spare parts is of prime concern for OEMs. Next to the traditional spare p... more The efficient supply of spare parts is of prime concern for OEMs. Next to the traditional spare parts sources in form of final order and remanufacturing, the option to buy back broken products prevents the OEM from fulfilling his spare parts availability obligation in the end-of-life phase and increases his ability to remanufacture. This contribution seeks to identify optimal buy-back strategies for different settings regarding information availability and buy-back flexibility.

Research paper thumbnail of On how buyback and remanufacturing strategies affect the profitability of spare parts supply chains

International Journal of Production Economics, 2011

The purpose of this paper is to provide a case-based framework to offer insights on the opportuni... more The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage spare parts supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they themselves repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control over demand which might be obtained by offering buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is the provision of a simple deterministic framework for answering the question whether a buyback option should be offered by the OEM to the repair shops, and which buyback price should be paid for each returned core. We further highlight the impact of remanufacturing performed at the OEM on the profitability of buyback.

Research paper thumbnail of A continuous time inventory model for a product recovery system with multiple options

International Journal of Production Economics, 2002

Most production and inventory management models for reverse logistics are restricted to stationar... more Most production and inventory management models for reverse logistics are restricted to stationary demands and returns and do not address seasonal effects and product life cycles. Therefore, we consider a deterministic model with dynamic demands and returns. Then ...

Research paper thumbnail of Dual sourcing using capacity reservation and spot market: Optimal procurement policy and heuristic parameter determination

European Journal of Operational Research, 2013

This contribution focuses on the cost-effective management of the combined use of two procurement... more This contribution focuses on the cost-effective management of the combined use of two procurement options: the short-term option is given by a spot market with random price, whereas the long-term alternative is characterized by a multi period capacity reservation contract with fixed purchase price and reservation level. A reservation cost, proportional with the reservation level, has to be paid for the option of receiving any amount per period up to the reservation level. A long-term decision has to be made regarding the reserved capacity level, and then it has to be decided -period by period -which quantities to procure from the two sources. Considering the multi-period problem with stochastic demand and spot price, the structure of the optimal combined purchasing policy is derived using stochastic dynamic programming. Furthermore, a simple heuristic procedure is developed to determine the respective policy parameters. Finally, we present a comprehensive numerical study showing that our heuristic policy performs very well.

Research paper thumbnail of Combined sourcing and inventory management using capacity reservation and spot market

Leading companies in several industries purchase materials with the combined use of capacity rese... more Leading companies in several industries purchase materials with the combined use of capacity reservation contracts and spot market. We analyse the optimal and a simplified policy for making long-term capacity reservation and periodic ordering/inventory decisions using the above two sources under stochastic demand and random spot market price fluctuations. In a numerical study we assess the effects of demand and spot market price uncertainties and of other parameters on both the optimal and simplified policy. We provide insights into the interaction of capacity reservation decision, demand uncertainty induced safety inventory, and inventory resulting from forward buying on the spot market.

Research paper thumbnail of Optimal control of a one product recovery system with backlogging

... AND STEFAN MINNER AND RAINER KLEBER Faculty of Economics and Management, Otto-von-Guericke-Un... more ... AND STEFAN MINNER AND RAINER KLEBER Faculty of Economics and Management, Otto-von-Guericke-University Magdeburg, PO Box 4120, D-39016 Magdeburg, Germany In this paper a product recovery system for one product is investigated. ...

Research paper thumbnail of Modellgestützte Flexibilitätsanalyse von Strategien zur Ersatzteilversorgung in der Nachserienphase

Das Bestandsmanagement von Ersatzteilen stellt Hersteller langlebiger Industrie- und Konsumgüter ... more Das Bestandsmanagement von Ersatzteilen stellt Hersteller langlebiger Industrie- und Konsumgüter insbesondere in der Nachserienphase vor große Herausforderungen, da nach Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibilität nur noch in eingeschränktem Maße vorhanden ist. In diesem Beitrag werden Strategien, bestehend aus Kombinationen der am häufigsten genutzten Beschaffungsoptionen in Form von Abschlusslosbildung zu Serienbedingungen, Nachproduktion in kleineren Losen und

Research paper thumbnail of An Advanced Heuristic for Multiple-Option Spare Parts Procurement after End-of-Production

After-sales service is a major profit generator for more and more OEMs in industries with durable... more After-sales service is a major profit generator for more and more OEMs in industries with durable products. Successful engagement in after-sales service improves customer loyalty and allows for competitive differentiation through superior service like an extended service period after end of production during which customers are guaranteed to be provided with service parts. In order to fulfill the service guarantee

Research paper thumbnail of Reverse logistics in a pharmaceutical company: a case study

Schering spends considerable effort to undertake product recovery activities in pharmaceutical pr... more Schering spends considerable effort to undertake product recovery activities in pharmaceutical production. The two main recovery activities are by-product recycling and solvent reuse. The main driver for engaging in these activities is economical. Recovery leads to annual savings of approximately DM 25 million, which is about 8.5 % of the total production cost. This figure does not include additional savings

Research paper thumbnail of Simultane Maschinenbelegungs- und Personaleinsatzplanung in KMUs anhand eines Fallbeispiels aus der Druckereibranche

In dem vorliegenden Beitrag zur Produktionslogistik wird die auftragsorientierte Fertigung von Dr... more In dem vorliegenden Beitrag zur Produktionslogistik wird die auftragsorientierte Fertigung von Druckaufträgen in der maschinellen Werkstattproduktion klein- und mittelständischer Unternehmen (KMU) am Fallbeispiel einer Akzidenzdruckerei betrachtet. Wesentliche Planungsaufgaben stellen dabei die Maschinenbelegungs- und die Personaleinsatzplanung mit der Qualifikation der Mitarbeiter als verbindendem Element dar. In der Literatur und der praktischen Anwendung werden die Teilprobleme weitgehend getrennt voneinander betrachtet und häufig

Research paper thumbnail of On how the acquisition of recoverable parts influences the profitability of spare parts management for durables

In the management of spare parts for durables OEMs often face a sharp decline in sales of spare p... more In the management of spare parts for durables OEMs often face a sharp decline in sales of spare parts when the warranty period of their products ends. One reason for this effect is given by the high profitability of the after sales market which attracts competitors. If the competitors’ main sourcing option consists of repairing used or broken parts, an

Research paper thumbnail of On how buyback and remanufacturing strategies affect the profitability of spare parts supply chains

The purpose of this paper is to provide a case-based framework to offer insights on the opportuni... more The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage spare parts supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they themselves repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control over demand which might be obtained by offering buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is the provision of a simple deterministic framework for answering the question whether a buyback option should be offered by the OEM to the repair shops, and which buyback price should be paid for each returned core. We further highlight the impact of remanufacturing performed at the OEM on the profitability of buyback.

Research paper thumbnail of The Effect of Material Price and Product Demand Correlations on Combined Sourcing and Inventory Management

Both material sourcing and inventory management are important competitiveness factors, and it is ... more Both material sourcing and inventory management are important competitiveness factors, and it is a significant challenge to integrate the two areas. In sourcing, combined strategies using long-term contracts and the spot market received increasing attention recently, typically concentrating on the financial effects. However, there is limited research on the consequence of combined sourcing considering both purchasing and inventory effects from an operations point of view. In this paper, we analyze the effect of uncertainty on the combined sourcing decision under stochastic demand and random spot-market-price fluctuations and exploit the benefits of forward buying in periods with low spot-price realizations, but also of intended backordering in case of a high spot price. Since the decision on capacity reservation has to take into account the short-term utilization of each source which in turn depends on the available long-term contract capacity, decision making faces highly complex interactions between long-term and short-term decisions.

Research paper thumbnail of A Heuristic Approach for Integrating Product Recovery into Post PLC Spare Parts Procurement

ABSTRACT Product recovery gains increasing importance in spare parts acquisition, especially duri... more ABSTRACT Product recovery gains increasing importance in spare parts acquisition, especially during the post product-life-cycle (PLC) service period. Considering product recovery in addition to traditional procurement options (final order, extra production) makes the underlying stochastic dynamic planning problem highly complex. An efficient heuristic for solving the integrated procurement problem is developed, which can be used to exploit the exibility offered by product recovery.

Research paper thumbnail of Reverse logistics in a pharmaceutical company: the Schering case

Managing Closed-Loop Supply Chains, 2005

Research paper thumbnail of Managing Dynamic Product Recovery: An Optimal Control Perspective

Research paper thumbnail of Modellgestützte Flexibilitätsanalyse von Strategien zur Ersatzteilversorgung in der Nachserienphase

Zeitschrift für Betriebswirtschaft, 2009

Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibili... more Abschluss der Serienproduktion die zur einer effizienten Bedarfsbefriedigung notwendige Flexibilität nur noch in eingeschränktem Maße vorhanden ist. In diesem Beitrag werden Strategien, bestehend aus Kombinationen der am häufigsten genutzten Beschaffungsoptionen in Form von Abschlusslosbildung zu Serienbedingungen, Nachproduktion in kleineren Losen und Aufarbeitung von Altprodukten anhand eines mathematischen Planungsmodells bezüglich ihrer Flexibilitätseigenschaften untersucht. Unter praxisnahen Rahmenbedingungen zeigt sich, dass sowohl Nachproduktion als auch Aufarbeitung als Versorgungsoption -insbesondere aufgrund der ihnen innewohnenden Zeitflexibilität -eine hohe Kostenersparnis gegenüber einer reinen Abschlusslosbevorratung gewährleisten können, selbst wenn deren Stückkosten weitüber denjenigen der Serienproduktion liegen. Weiter stellt sich heraus, dass die Nachproduktion das größte Flexibilitätspotenzial besitzt, soweit es nicht durch Vorgabe von Mindestproduktionsmengen zu stark eingeschränkt wird. Die aufgrund ihrer Abhängigkeit vom Altproduktrückfluss aus Flexibilitätssicht eigentlich weniger attraktive Aufarbeitung kann der Nachproduktion im Endeffekt jedochüberlegen sein, sofern ihr Stückkostenvorteil hinreichend hoch ist. Schließlich ergibt sich, dass eine kombinierte Nutzung beider Versorgungsoptionen in der Nachserienphase in der Regel nur noch einen vergleichsweise geringen zusätzlichen Erfolgsbeitrag liefert.

Research paper thumbnail of Optimal control of production and remanufacturing in a simple recovery model with linear cost functions

OR Spektrum, 2001

In this paper, a recovery system for perishable items is introduced and developed considering pro... more In this paper, a recovery system for perishable items is introduced and developed considering production and remanufacturing capacity constraints. The system consists of two inventories, one for serviceable items and the other for returned and recoverable items. Taking the production cost, remanufacturing cost, disposal cost, and the loss caused by deterioration into account, the optimal control model is established to minimise the total cost. The continuous-time dynamic optimal production, remanufacturing and disposal rates that minimise the total cost are obtained using Pontryagin's maximum principle. Additionally, to highlight the advantage of the dynamic optimal policy, the case of the static optimal policy that does not vary with time is investigated and compared with the dynamic policy. It is shown that the dynamic optimal policy is significantly better than the static optimal policy. A numerical example is provided to illustrate the proposed methods.

Research paper thumbnail of Dynamic buy-back for product recovery in end-of-life spare parts procurement

International Journal of Production Research, 2012

The efficient supply of spare parts is of prime concern for OEMs. Next to the traditional spare p... more The efficient supply of spare parts is of prime concern for OEMs. Next to the traditional spare parts sources in form of final order and remanufacturing, the option to buy back broken products prevents the OEM from fulfilling his spare parts availability obligation in the end-of-life phase and increases his ability to remanufacture. This contribution seeks to identify optimal buy-back strategies for different settings regarding information availability and buy-back flexibility.

Research paper thumbnail of On how buyback and remanufacturing strategies affect the profitability of spare parts supply chains

International Journal of Production Economics, 2011

The purpose of this paper is to provide a case-based framework to offer insights on the opportuni... more The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage spare parts supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they themselves repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control over demand which might be obtained by offering buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is the provision of a simple deterministic framework for answering the question whether a buyback option should be offered by the OEM to the repair shops, and which buyback price should be paid for each returned core. We further highlight the impact of remanufacturing performed at the OEM on the profitability of buyback.

Research paper thumbnail of A continuous time inventory model for a product recovery system with multiple options

International Journal of Production Economics, 2002

Most production and inventory management models for reverse logistics are restricted to stationar... more Most production and inventory management models for reverse logistics are restricted to stationary demands and returns and do not address seasonal effects and product life cycles. Therefore, we consider a deterministic model with dynamic demands and returns. Then ...

Research paper thumbnail of Dual sourcing using capacity reservation and spot market: Optimal procurement policy and heuristic parameter determination

European Journal of Operational Research, 2013

This contribution focuses on the cost-effective management of the combined use of two procurement... more This contribution focuses on the cost-effective management of the combined use of two procurement options: the short-term option is given by a spot market with random price, whereas the long-term alternative is characterized by a multi period capacity reservation contract with fixed purchase price and reservation level. A reservation cost, proportional with the reservation level, has to be paid for the option of receiving any amount per period up to the reservation level. A long-term decision has to be made regarding the reserved capacity level, and then it has to be decided -period by period -which quantities to procure from the two sources. Considering the multi-period problem with stochastic demand and spot price, the structure of the optimal combined purchasing policy is derived using stochastic dynamic programming. Furthermore, a simple heuristic procedure is developed to determine the respective policy parameters. Finally, we present a comprehensive numerical study showing that our heuristic policy performs very well.

Research paper thumbnail of Combined sourcing and inventory management using capacity reservation and spot market

Leading companies in several industries purchase materials with the combined use of capacity rese... more Leading companies in several industries purchase materials with the combined use of capacity reservation contracts and spot market. We analyse the optimal and a simplified policy for making long-term capacity reservation and periodic ordering/inventory decisions using the above two sources under stochastic demand and random spot market price fluctuations. In a numerical study we assess the effects of demand and spot market price uncertainties and of other parameters on both the optimal and simplified policy. We provide insights into the interaction of capacity reservation decision, demand uncertainty induced safety inventory, and inventory resulting from forward buying on the spot market.