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Ioannis Ganas

Other affiliations: University of Ioannina
Bio: Ioannis Ganas is an academic researcher from American Hotel & Lodging Educational Institute. The author has contributed to research in topics: Inventory control & Time horizon. The author has an hindex of 5, co-authored 9 publications receiving 283 citations. Previous affiliations of Ioannis Ganas include University of Ioannina.

Papers
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Journal ArticleDOI
TL;DR: An inventory model with general ramp type demand rate, time dependent (Weibull) deterioration rate and partial backlogging of unsatisfied demand is considered and the optimal replenishment policy for the model is derived.

257 citations

Journal ArticleDOI
TL;DR: An explicit formula for the optimal total cost as a function of the model parameters and the number of cycles of the policy is presented, and stability regions for any solution considering simultaneous variations on all cost and demand parameters are found.
Abstract: We consider the single-product lot-sizing problem over a finite planning horizon. Demand at each period is constant, and excess demand is completely backlogged. Holding and backlogging costs are proportional to the amount of inventory stocked or backlogged, while ordering cost is fixed, independent of the quantity ordered. The optimal policy targets to minimize the total relevant costs over the planning horizon. The key results of this paper are: (1) an explicit formula for the optimal total cost as a function of the model parameters and the number of cycles of the policy; (2) a new, polynomial-time algorithm which determines the overall optimal policy; and (3) stability regions for any solution considering simultaneous variations on all cost and demand parameters. The proposed algorithm is easy to implement and therefore is suitable for practical use.

13 citations

Journal ArticleDOI
TL;DR: An economic model predictive control strategy for the inventory routing problem under demand uncertainty and it is shown that EMPC offers a useful tool for producing balanced decisions between transportation and inventory costs and tracking of the safety inventory levels.
Abstract: The paper proposes an economic model predictive control (EMPC) strategy for the inventory routing problem under demand uncertainty. The strategy is illustrated using an application on industrial gas distribution systems, where the product is transported to customers in small tanks and the inventory levels at the customers’ sites are monitored and controlled by the supplier following a vendor managed inventory approach. The objective is to produce balanced decisions for the joint routing and the inventory control problem over the planning horizon with respect to the decision maker’s perspective against stock-out risk. The proposed EMPC strategy makes use of a mixed integer mathematical programming optimization model that describes the deterministic inventory routing problem with simultaneous pickups and deliveries over a specific planning horizon. A time series decomposition forecasting model is used for predicting future demand and an exact linearization of the quadratic term of the objective function guarantees optimality of the solutions. The proposed methodology is illustrated using two examples featuring a single distribution centre, and three customers with simple and complex demand profiles. It is shown that EMPC offers a useful tool for producing balanced decisions between transportation and inventory costs and tracking of the safety inventory levels.

11 citations

Journal ArticleDOI
TL;DR: This paper presents rules concerning the optimal policy and stability regions for the single product periodic review inventory problem with stationary demands, over a finite horizon, using the Lot-Sizing Index (LSI).
Abstract: In this paper we present rules concerning the optimal policy and stability regions for the single product periodic review inventory problem with stationary demands, over a finite horizon. The key parameter to the whole study is the Lot-Sizing Index (LSI) introduced by Blackburn and Millen. Two algorithms are presented. The first one constructs stability regions which are expressed as intervals of the LSI parameter, covering the whole range of its values. The proposed algorithm is very simple to understand and implement, and most importantly, it provides a solution table which can be used by the decision maker to easily determine the optimal policy for any problem with a given horizon and any possible combination of its cost parameters, namely any LSI value. The second proposed algorithm determines the optimal policy for any given LSI value; it constitutes a completely different approach to that of the Wagner–Whitin algorithm and requires very little computational effort.

7 citations

Journal ArticleDOI
TL;DR: A two-warehouse inventory model for noninstantaneous deteriorating items with price and time-dependent demand is developed and a simple solution procedure to determine the optimal pricing and replenishment schedule is proposed.
Abstract: In this paper an inventory control system for deteriorating items with price and time-dependent demand is studied. The majority of the existing literature in inventory systems for deteriorating items, deals with items that are subject to deterioration as soon as they enter the warehouse. However, there are items that have a shelf-life and start deteriorating after a time lag (noninstantaneous deteriorating items). Under some special circumstances, i.e., attractive price discount, low storage cost, high demand, etc; the procurement of a large amount of such items at a time is decided. Because of the fixed capacity of the own warehouse (OW), a rented warehouse (RW) is used to store the excess quantity. In the present paper, a two-warehouse inventory model for noninstantaneous deteriorating items is developed. Shortages at OW are also allowed and partially backlogged at a rate, which is any nonincreasing function of the waiting time up to the next replenishment. For this model, we propose a simple solution procedure to determine the optimal pricing and replenishment schedule.

7 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors consider single-level lot sizing problems, their variants and solution approaches, together with exact and heuristic approaches for their solution, and conclude with some suggestions for future research.
Abstract: Lot sizing is one of the most important and also one of the most difficult problems in production planning. This subject has been studied extensively in the literature. In this article, we consider single-level lot sizing problems, their variants and solution approaches. After introducing factors affecting formulation and the complexity of production planning problems, and introducing different variants of lot sizing and scheduling problems, we discuss single-level lot sizing problems, together with exact and heuristic approaches for their solution. We conclude with some suggestions for future research.

670 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an up-to-date review of the advances made in the field of inventory control of perishable items (deteriorating inventory) and use the classification of Goyal and Giri based on shelf life characteristics and demand characteristics.

546 citations

Journal ArticleDOI
TL;DR: A literature review of the fresh produce supply chain management (FSCM) is presented in this article, where the main interest is towards consumer satisfaction and revenue maximization with post-harvest waste reduction being a secondary objective.
Abstract: Purpose – The purpose of this paper is to present a literature review of the fresh produce supply chain management (FSCM). FSCM includes the processes from the production to consumption of fresh produce (fruits, flowers and vegetables).Design/methodology/approach – Literature review is done by systematically collecting the existing literature over a period of 20 years (1989‐2009) and classifying it on the basis of structural attributes such as problem context, methodology and the product under consideration. The literature is also categorized according to the geographic region and year of publication.Findings – There is an increase in interest towards FSCM still there is an absence of a journal with the prime attention towards FSCM. The key finding of this review is that the main interest is towards consumer satisfaction and revenue maximization with post‐harvest waste reduction being a secondary objective. It is revealed from the review that most of the literature is fragmented and is in silos. Lack of d...

362 citations

Book
01 Jan 1976
TL;DR: In this paper, the authors describe how to use statistical modeling and analysis methods for forecasting and prediction problems, and provide a user-oriented second edition of the first edition of this book.
Abstract: This practical, user-oriented second edition describes how to use statistical modeling and analysis methods for forecasting and prediction problems. Statistical and mathematical terms are introduced only as they are needed, and every effort has been made to keep the mathematical and statistical prerequisites to a minimum. Every technique that is introduced is illustrated by fully worked numerical examples. Not only is the coverage of traditional forecasting methods greatly expanded in this new edition, but a number of new techniques and methods are covered as well.

323 citations

Journal ArticleDOI
TL;DR: The author develops an EOQ model for time varying deterioration rate where demand and deterioration rate are both time-dependent and the profit function of the model is maximized.

243 citations