OPTIMAL OPERATIONAL DECISIONS WHEN A MANUFACTURER OFFERS TRADE CREDIT TO HIS RETAILER

In this paper, we develop models to determine operational and financial decisions of a supply chain under the condition that the retailer faces a financial constraint and the manufacturer can offer trade credit to assist the retailer. We first study the case where the retailer is risk-neutral, and derive the optimal ordering and financial decisions. Then, the case where the retailer is risk-averse （downside risk） is studied and-the effects of the risk on the retailer and manufacturer＇s operational and financial decisions are discussed. Finally, numerical examples are provided to conduct managerial analysis.

CAPACITY ALLOCATION AND COORDINATION ISSUES FOR THE TIMELY PROCESSING OF OUTSOURCED OPERATIONS

We consider dynamic capacity booking problems faced by multiple manufacturers each outsourcing certain operations to a common third-party firm. Each manufacturer, upon observing the current state of the third-party schedule, books capacity with the objective to jointly minimize holding costs that result from early deliveries, tardiness penalties due to late deliveries, and third-party capacity booking costs. When making a reservation, each manufacturer evaluates two alternative courses of action： （i） reserving capacity not yet utilized by other manufactures who booked earlier; or （ii） forming a coalition with a subset or all of other manufacturers to achieve a schedule minimizing coalition costs, i.e., a centralized schedule for that coalition. The latter practice surely benefits the coalition as a whole; however, some manufacturers may incur higher costs if their operations are either pushed back too much, or delivered too early. For this reason, a cost allocation scheme making each manufacturer no worse than they would be when acting differently （i.e., participating in a smaller coalition or acting on their own behalf,） must accompany centralized scheduling for the coalition. We model this relationship among the manufacturers as a cooperative game with transferable utility, and present optimal and/or heuristic algorithms to attain individually and eoalitionally optimal schedules as well as a linear program formulation to find a core allocation of the manufacturers＇ costs.

Cooperation and Contract Design in Project Management with Outsourcing

We study a project management problem where the prime contractor needs to outsource tasks to subcontractors with the required resources.Successful execution of the project requires proper coordination among the subcontractors,as well as contract design by the prime contractor to incentivize the subcontractors.By modeling the subcontractors’coordination problem as a cooperative game,we develop a profit sharing scheme to facilitate the subcontractors’cooperation.We consider two contract designs for the prime contractor:a uniform contract across all subcontractors,and a nonuniform one that customizes incentives for each subcontractor.We propose efficient algorithms to solve the implicit optimization problems for optimal contract parameters.Computational experiments show that the pooling effect of subcontractors’cooperation mitigates the negative impact of poor estimates about the crashing cost and resource availability.We observe three unexpected results through the randomized computation experiments:(i)the subcontractors’profits may decrease if they provide false information;(ii)it is safer for the prime contractor to overestimate subcontractors’crashing costs than underestimate them;and(iii)uniform contracts deliver more project profit for the subcontractors in the coalitions.

On the Quasi-Concavity of Equipment Sharing Games with Perishable Raw Materials

We study the equipment sharing problem where a group of food&beverage companies share the same equipment of a contractor and wish to have their processing tasks coordinated such that the total cost is minimized.The raw materials to be processed are perishable,which incur a decay cost as time goes.One key issue of this equipment sharing problem is how to allocate the total cost among the participants.We apply cooperative game theory to tackle this issue and formulate the problem as an equipment sharing game.First,we study the 1-equipment sharing game in which all participants share one equipment.We show that the 1-equipment sharing game is quasi-concave when the fixed operation cost is larger than a certain value.We then discuss the special case where the processing time for all participants is equal.For this case,we further investigate the properties of the 1-equipment sharing game and the multi-equipment sharing game.We identify the conditions under which the Shapely value and the T-value can be easily calculated for the 1-equipment and multi-equipment sharing games.

Chemical composition and antimicrobial activity of the essential oil of Cacalia tangutica (Maxim.) Hand.-Mazz

Essential oil of the subterranean part of Cacalia tangutica(Maxim.)Hand.-Mazz was analyzed by gas chromatography(GC)-mass spectrum(MS)technique in two different capillary columns of different polarities.Thirty-one components were identified in the oil and the main compounds were a-zingiberene(13.49%),germacrene D(10.76%),α-pinene(8.54%),caryophyllene(Z-)(6.36%),linalool(6.16%),β-myrcene(4.89%),β-ocimene(Z-)(4.40%)and ocimenone(Z-)(3.58%).The antimicrobial activity of the oil was evaluated against 2 fungi and 12 bacteria including 6 clinically isolated strains using the agar disc diffusion and broth microdilution methods.The results show that the oil presented a broad antimicrobial spectrum and had better antimicrobial activity against yeast and gram-positive bacteria.The minimum inhibitory concentration values were 0.16–5.00 g/L and minimum bactericidal concentration values were 0.16–5.00 g/L.