Peter Kelle

Peter Kelle
Louisiana State University | LSU · Department of Information Systems & Decision Sciences (ISDS)

About

50
Publications
7,698
Reads
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1,786
Citations
Citations since 2016
1 Research Item
664 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Additional affiliations
August 1988 - present
Louisiana State University
Position
  • Professor (Full)

Publications

Publications (50)
Article
Full-text available
In this paper, we focus on the role of inventory management as a means for operational hedging by dual sourcing of commodities using a multi-period option contract and spot market. We consider a manufacturing company in a make-to-stock environment with uncertain product demand. We replace the common i.i.d. price assumption that is typical in operat...
Chapter
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 fluctu...
Technical Report
Full-text available
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 resear...
Article
Emergency supply chain management is often in the focal point of public scrutiny. Expected cost minimization may result in unacceptable high shortage for scenarios with small probabilities that is hardly tolerated by the public. To decrease the loss for the worst-case scenario, the min-max regret criterion could be applied for the pre-positioning d...
Technical Report
Full-text available
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 fluctu...
Article
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, proporti...
Article
Full-text available
Since highway improvement project selection requires screening thousands of road segments with respect to crashes for further analysis and final project selection, we provide a two-step project selection methodology and describe an application case to demonstrate its advantages. In the first step of the proposed methodology, we will use odds agains...
Article
Capacity reservation contracts and spot markets are two alternative purchasing practices. We focus on the cost-effective management of the combined use of these two procurement sources. Due to the variability of the spot market prices and demand uncertainty, the flexibility of combined sourcing can be advantageous. Spot market purchasing is a benef...
Article
The 2010 special issue of International Journal of Production Economics brings together an interdisciplinary group of scholars with a keen interest in the effective functioning of supply chains in the face of human disaster. A crisis or disaster can be the result from a wide variety of adversity. Only when effective response organizations work toge...
Chapter
Full-text available
The models discussed in the present paper are generalizations of the models introduced previously by A. Prékopa [6] and M. Ziermann [13]. In the mentioned papers the initial stock level of one basic commodity is determined provided that the delivery and demand process allow certain homogeneity (in time) assumptions if they are random. Here we are d...
Article
Random yield is still prevailing in several industries despite quality improvement efforts. In this case, the supply chain partners jointly must find the best way to cope with yield uncertainty. We focus on the inventory-related costs that can be influenced by adjusting the ordering, setup, and delivery policy to the random yield. The yield model o...
Article
We consider a two-echelon inventory system with one warehouse and several stores. The warehouse as well as the stores are controlled by periodic review (s, S) inventory policies. We study the interrelationship between the safety stocks at the warehouse and the stores. Stockouts at the warehouse will result in supply delays to the stores and cause t...
Article
The ability of local government agencies to effectively utilise technologies to share information constitutes a critical element in nationwide efforts to fight terrorism, combat crime, and protect citizen safety. Alarmingly, current practices have neither effectively transferred information that local government agencies need, nor adequately captur...
Article
This exploratory research examines the pharmaceutical inventory control practices of a local area hospital and demonstrates the utility of two alternative quantitative approaches. Pharmaceuticals represent a large cost factor for most hospitals due to the significant costs of these products and the storage and control requirements. The hospital sto...
Chapter
A recent visit to a local emergency room (ER) motivated one of the coauthors to literally investigate the crucial element of supply chain management (SCM) within the healthcare system. After experiencing eight hours of delays in the ER waiting room and witnessing incredible lags in the medication dispensing process and even further impediments to t...
Article
Full-text available
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, reservation level and capacity reservation cost. C...
Article
The deficiencies in previous quantitative models for buyer–supplier coordination in a just-in-time (JIT) environment are corrected. An expanded model incorporating additional factors is developed and the factors are ranked through a detailed numerical analysis. Factor ranks are then compared with results of a series of semi-formal interviews with s...
Chapter
Stochastic models are formulated for the optimal allocation of the safety stocks in raw material, in internal stocks on the different production levels and in finished goods. Simple approximate solutions are derived, too.
Article
Potential sulfate reduction and in situ hydrogen sulfide emission rates for three Louisiana marsh soils of varying salinities (salt, brackish, and freshwater) were used to evaluate the influence of soil physicochemical parameters on sulfur transformations in different seasons (summer, winter, and spring). Solid adsorbent preconcentration and emissi...
Article
The transaction based integrated Enterprise Resource Planning (ERP) software provides different tools that can support supply chain integration but at the same time it has several features that obstructs the integration with business partners. We concentrate on the inventory management aspects of supply chain coordination reviewing the recent quant...
Article
Several studies have focused on the qualitative aspects of establishing and negotiating buyer–supplier partnerships, including Just-In-Time (JIT) supply, but few quantitative models and investigations are available in this area. We explore the two typical cases: supplier's dominance, with large production lot sizes and shipment sizes and buyer's do...
Article
The importance of reliable supply is increasing with global sourcing and just-in-time (JIT) production. The transition to JIT purchasing implies single sourcing, which often involves problems with unreliable vendors. If a single, reliable supplier is not available, the order can be split among the vendors until a reliable supplier emerges. We addre...
Article
In many supply chains, the variability of orders may considerably increase relative to the variability of the buyers' demand. This variability increase is largely an effect of the ordering policy. This phenomenon, which has become known as the bullwhip effect, makes supply chain planning difficult. We consider the following three basic elements of...
Article
The transition from a traditional purchasing system to a JIT purchasing system can be a slow process or even unattainable, because of unreliable suppliers. The purchaser tries to co-operate with the vendor, with the goal of receiving smaller, more frequent deliveries, on time, with the quality and quantity required. Often the vendor is ready to co-...
Article
This paper discusses a condition based maintenance model with exponential failures, and fixed inspection intervals. A condition of the equipment, such as vibration, is monitored at equidistant time intervals. If the variable indicating the condition is above a threshold an instantaneous maintenance action is performed and the monitored condition ta...
Article
Two production/inventory control systems are compared for a chemical process line that produces several different products, one at a time. Because of the complexity of the distribution system, little or no feedback information on inventory levels is available. Thus, a fixed production cycle schedule, based on long-range forecast, is used. This push...
Article
Practitioners of maintenance scheduling sometimes use a simple analytic formula, derived based on inspection scheduling, as a heuristic to determine the length of the preventive maintenance period. The sensitivity of this heuristic solution is analyzed and the cost penalties are calculated compared to the exact solution that utilizes the lifetime d...
Article
An extension to the economic lot scheduling problem is given for a single-machine, multi-product line under random demands. The goal is to find the length of production cycles that minimizes the sum of setup and inventory holding costs per unit of time and satisfies the demand for each product at the required service level. First, the single-produc...
Article
Reliability-type inventory models are formulated to determine the minimal safety stock that will provide a prescribed service level for satisfying demand. We give an extension of such a model as an approximation for handling the specific features of Just-in-Time (JIT) production and service systems.
Article
In this article we consider an item for which a continuous review, reorder point, order quantity inventory control system is used. The amount of safety stock required depends upon, among other factors, the average value and variability of the length of the replenishment lead time. One way to reduce these quantities is to split orders among two or m...
Article
In this paper we consider the policy of splitting each replenishment order among two or more vendors. This action reduces the expected time until the first replenishment arrives, as well as its variance. Thus using the same safety stock, a higher service level can be achieved or the safety stock can be reduced without decreasing the service level....
Article
Full-text available
A number of organizations sell products in containers that can be reused. The time from issue to return of an individual container is usually not known with certainty and there is a chance that the container is never returned (because of loss or irrepairable damage). Consequently, even under a level demand pattern new containers must be acquired fr...
Article
In this paper we consider an item that is sold in a number of different prescribed sizes, an example being an item of clothing. We first deal with the situation where the total demand for a forthcoming period is known accurately but only historical or subjective estimates of the fractions of demand in each size are available. A procedure is develop...
Article
A number of organizations sell products in containers that can be reused. Illustrative cases include beverages (in kegs, plastic cartons, etc.) and liquid gases (in cylinders). The time from issue to return of an individual container is usually not known with certainty and there is a chance that the container is never returned (because of loss or i...
Article
A chance constrained model and a model for probability maximization is formulated for the investment planning problem of risky projects. A budget constraint is considered, too. A sequential stochastic decision making process is formulated and analyzed. Solution method is described for a special case.
Article
The safety stocks of internal stores are analysed in a production line. Production may often be disturbed by random factors such as machine failures, faulty products, breakdowns, etc. In this case both the demand and delivery process of each internal store have to be described by random processes, mostly by random step functions. If there is consid...
Article
Inventory models are considered in which the delivery of an order occurs not on one occasion but at random moments of a period in random parts. We give two extensions of the reliability type inventory model of A. Prékopa. In this model a known constant demand rate is assumed and a simple approximate formula is given for the initial stock of the ord...
Article
The objective of this paper is to describe the steps in and results of current research carried out within the framework of a special long-term project supervised and financed by the Hungarian Academy of Sciences. Since the research, which started in 1976, will go on for several more years — and so we are far from final results — this paper is most...
Article
The problem of material supply of an automatic asphalt mixing plant is considered in this paper. First a deterministic model for the optimal mixture rates is discussed, then stochastic inventory control models for the hot depots of mixture machines are presented. The main practical problem is to find the optimal hot depot capacities for which the p...

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Project (1)
Archived project
This project focuses on the cost-effective management of the combined use of two procurement options: a spot market with random price and a multi period capacity reservation contract with fixed purchase price and reservation level. The goal is to find structural properties of the optimal combined purchasing policy under different conditions. Exploiting these properties, advanced heuristic are developed to determine the respective policy parameters. Finally, insights into the system’s behavior under problem parameter variations are derived.