A General Framework for Cooperation under Uncertainty

In this paper, we introduce a general framework for situations with decision making under uncertainty and cooperation possibilities. This framework is based upon a two stage stochastic programming approach. We show that under relatively mild assumptions the cooperative games associated with these situations are totally balanced and, hence, have non-empty cores. Finally, we consider several example situations, which can be studied using this general framework.Two-stage stochastic programming;cooperative game theory;core

On the Convexity of News Vendor Games

This study considers a simple newsvendor situation that consists of n retailers, all selling the same item with common purchasing costs and common selling prices.Groups of retailers might increase their expected joint profit by inventory centralization, which means that they make a joint order to satisfy total future demand.The resulting newsvendor games are shown to have non-empty cores in the literature.This study investigates convexity of newsvendor games.We focus our analysis on the class of newsvendor games with independent symmetric unimodal demand distributions after providing several examples outside this class that are not convex.Several interesting subclasses, containing convex games only, are identified.Additionally, we illustrate that these results can not be extended to all games in this class.game theory;inventory centralization;newsvendor;convexity

Cooperation between Multiple Newsvendors with Warehouses

This study considers a supply chain that consists of n retailers, each of them facing a newsvendor problem, m warehouses and a supplier.The retailers are supplied with a single product via some warehouses.In these warehouses, the ordered amounts of goods of these retailers become available after some lead time.At the time that the goods arrive at the warehouses, demand realizations are known by the retailers.The retailers can increase their expected joint profits by coordinating their orders and making allocations after demand realization.For this setting, we consider an associated cooperative game between the retailers.We show that this associated cooperative game has a nonempty core. Finally, we study a variant of this game, where the retailers are allowed to leave unsold goods at the warehouses.supply chain management;newsvendor;warehouse;game theory;balancedness

Stability and monotonicity in newsvendor situations

Cataloged from PDF version of article.This study considers a supply chain that consists of n retailers, each of them facing a newsvendor problem, and a supplier. Groups of retailers might increase their expected joint profit by joint ordering and inventory centralization. However, we assume that the retailers impose some level of stock that should be dedicated to them. In this situation, we show that the associated cooperative game has a non-empty core. Afterwards, we concentrate on a dynamic situation, where several model cost parameters and the retailers’ dedicated stock levels can change. We investigate how the profit division might be affected by these changes. We focus on four monotonicity properties. We identify several classes of games with retailers, where some of the monotonicity properties hold. Moreover, we show that pairs of cooperative games associated with newsvendor situations do not necessarily satisfy these properties in general, when changes in dedicated stock levels are in concern

A General Framework for Cooperation under Uncertainty

In this paper, we introduce a general framework for situations with decision making under uncertainty and cooperation possibilities. This framework is based upon a two stage stochastic programming approach. We show that under relatively mild assumptions the cooperative games associated with these situations are totally balanced and, hence, have non-empty cores. Finally, we consider several example situations, which can be studied using this general framework.

Cooperation between Multiple Newsvendors with Warehouses

This study considers a supply chain that consists of n retailers, each of them facing a newsvendor problem, m warehouses and a supplier.The retailers are supplied with a single product via some warehouses.In these warehouses, the ordered amounts of goods of these retailers become available after some lead time.At the time that the goods arrive at the warehouses, demand realizations are known by the retailers.The retailers can increase their expected joint profits by coordinating their orders and making allocations after demand realization.For this setting, we consider an associated cooperative game between the retailers.We show that this associated cooperative game has a nonempty core. Finally, we study a variant of this game, where the retailers are allowed to leave unsold goods at the warehouses.

Effect of twine thickness on selectivity of gillnets for bogue, Boops boops,in Turkish waters

To investigate the effect of twine thickness on the selectivity of multifilament gillnet targeting bogue,Boops boops L., four different stations were sampled between March and November 2008 in the northern Aegean Sea. Gillnets with 22, 23, and 25 mm nominal mesh size (bar length) each having two different twine thicknesses (approximately 0.45 mm and 0.54 mm ∅) were applied for this purpose. The deviances from the SELECT method revealed that lognormal models provided the best fits for both of the twine thicknesses. Results from the two-way ANOVA analyses revealed that the mean total lengths increased with the mesh size (F = 87.36; df = 2; P < 0.0001) and decreased with the twine thickness (F = 46.12; df = 1; P < 0.0001). The 22 mm mesh size net (0.45 mm ∅) captured significantly larger fish than the 23 mm mesh size net (0.54 mm ∅) probably due to the higher elasticity and flexibility of the thinner twine. Thus, fisheries managers should take into consideration the twine thickness while advising mesh size regulations in gillnet fisheries

A safe protocol for tuberculin test assessment in a country where BCG vaccination is mandatory

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