مقاله سال ۲۰۱۶

 مجله امگا – Omega

Consider a manufacturer or retailer who procures (or, ‘sources’) a certain product or service, to use directly or indirectly in meeting the stochastic demand that she faces. Considering the manufacturing environment as an example, the product that is to be procured (or, the ‘item’) can be supplied by a finite number of capacitated external suppliers, and the manufacturer must decide which of the sources to utilize and to what extent. One could prefix the procurement quantity based on inventory- and production-related costs, and then find the least costly solution from the available pool of suppliers with corresponding price structures and capacities. However, the optimal sourcing (procurement) decision under stochastic demand requires an integrated approach, using all of the cost parameters and capacity and price information of alternative suppliers simultaneously.

Supplier price and capacity information could be collected by making use of e-business infrastructure or organized industrial associations, or by contacting qualified suppliers, using a requestfor-quotations (RFQ). These sources may have different capacities and price structures, but we consider them to be identical in terms of their function, i.e. the item’s characteristics do not depend on the supplier. We do not restrict our analysis to a particular cost function for procurement, and we allow, for example, for a separate fixed cost for initiating the use of each source, for logistics costs that might depend on the geographical location of the suppliers, and for nonlinear unit variable costs. Progressive or all-units quantity discounts are special cases. Moreover, the “cost-of-doing business” with each supplier might incur non-linear cost factors [22]. The suppliers’ capacity utilization might result in re-evaluating the remaining available capacities, inducing quantity-dependent price quotations.

Purchasing is a common operation for all types of businesses. Kaplan and Sawhney [20] analyze business-to-business e-commerce marketplaces and classify the purchasing market as manufacturing inputs and operating inputs, in terms of what businesses buy and as systematic sourcing and spot sourcing, in terms of how they buy. Our approach applies to any type of manufacturing or operating inputs that face stochastic demand and that are purchased from the spot market: the ‘exchanges’ and ‘yield managers’, respectively [20]. There are numerous web-based platforms on the market that can materialize the sourcing methodologies prescribed in this study. There are general purpose B2B e-commerce platforms such as Ariba [5], Fiatech [13], and 1 Point Commerce [1] and specific platforms operated by companies for their operations such as the ones by Ford [14], Foster Wheeler [15], and Hilton [18].