## 2 Smart Supply Chain with Additive Manufacturing  
### The Concept of Smart Supply Chains  
As customized products increase, companies require the ability to produce a variety of products and form an integrated network in order to efficiently utilize geographically distributed resources. A network providing customized products according to customer needs was proposed as the smart supply chain concept [13]. Later, [PERSON] and [PERSON] [14] focused on the role of small- and medium-sized enterprises (SMEs) in competing with big companies. Geographically spread but electronically linked SMEs could form a dynamic and adaptive network without obligatory egalitarian responsibility, which is different from traditional collaborative networks. The dynamic and adaptive network is referred to as a dispersed manufacturing network. Similar concepts of connecting companies to generate collaborative and competitive organizations include collaborative networks [15; 16], responsive supply chains [17], and distributed manufacturing [18].  
The concept of the smart supply chain is not new and has been discussed by many researchers and practitioners; however, recent research emphasizes the role of advanced ICT. [PERSON] et al. [19] is one of the earlier works that proposes a smart supply chain using wireless sensors. As an example, they developed a prototype application to handle Sears' customized orders. [PERSON] and [PERSON] [20] suggest that the next step in the development of wireless sensors is the higher-level integration of inter-organizations, and e-commerce within a self-managed smart supply chain. In subsequent research, [PERSON] and [PERSON] [21] show how radio-frequency identification (RFID) could be adopted to implement smart supply chain models to deal with their dynamic nature. [PERSON] and [PERSON] [22] consider the next generation supply chain as a cyber-physical system (CPS)--an advanced network using a physical system and cloud service. They emphasize that a pre-determined supply chain structure will evolve into a dynamic and temporary network. The customer-centered new supply chain is more flexible, adaptable, and intelligent, so that it could operate without human involvement.  
[PERSON] [23] claims that a smarter supply chain has three properties: (1) instrumented--more data in a supply chain would be generated by various devices such as sensors, RFID, and actuators;(2) interconnected--more objects in a supply chain would be extensively connected and lead to massive collation among them; and (3) intelligent--more intelligent systems would help people by making real-time decisions and predicting future events. Recently, [PERSON] et al. [24] added three additional characteristics, including automated, integrated, and innovative.  
This paper focuses on the flexibility and dynamics required to make customized products, which could be achieved by employing new ICT such as sensors, 3D-printers, CPS, and IoT. It considers a set of geographically dispersed smart factories sharing their machines and collaborating to make customized products through a cloud system--called connected smart factories. They are able to share machines through entire processes, or partially share some processes to make a customized product. Then, smart supply chains could be dynamically organized to fulfill a customer order and dissolve after order fulfillment, using the advanced ICT mentioned above.