management (CRM) Requirements chain management (RCM) Dynamic Capabilities Theory Dynamic Management Theory Available-to-promise (ATP) Supply Chain Roadmap Optimal Positioning of the Delivery Window (OPDW) However, the unit of analysis of most of these theories is not the supply chain but rather another system, such as the firm or the supplier-buyer relationship. Among the few exceptions is the relational view, which outlines a theory for considering dyads and networks of firms as a key unit of analysis for explaining superior individual firm performance (Dyer and Singh, 1998). Organization and governance The management of supply chains involve a number of specific challenges regarding the organization of relationships among the different partners along the value chain. Formal and informal governance mechanisms are central elements in the management of supply chain. Particular combinations of governance mechanisms may impact the relational dynamics within the supply chain. The need for interdisciplinarity in SCM research has been pointed out by academics in the field. Supply chain centroids In the study of supply-chain management, the concept of centroids has become a useful economic consideration. In mathematics and physics, a centroid is the arithmetic mean position of all the points in a plane figure. For supply chain management, a centroid is a location with a high proportion of a country's population and a high proportion of its manufacturing, generally within . In the US, two major supply chain centroids have been defined, one near Dayton, Ohio, and a second near Riverside, California. The centroid near Dayton is particularly important because it is closest to the population center of the US and Canada. Dayton is within 500 miles of 60% of the US population and manufacturing capacity, as well as 60% of Canada's population. The region includes the interchange between I-70 and I-75, one of the busiest in the nation, with 154,000 vehicles passing through per day, of which 30–35% are trucks hauling goods. In addition, the I-75 corridor is home to the busiest north–south rail route east of the Mississippi River. A supply chain is the network of all the individuals, organizations, resources, activities and technology involved in the creation and sale of a product. A supply chain encompasses everything from the delivery of source materials from the supplier to the manufacturer through to its eventual delivery to the end user. The supply chain segment involved with getting the finished product from the manufacturer to the consumer is known