# BIM-Based Management System for Off-Site Construction Projects
## 4 System Implementation
### System Functions and Implementation Detail
#### 4.3.4 Logistics Management  
The system enables logistics management to ensure that the inventory stored after production in the factory is shipped and delivered to the site on the scheduled date. The shipping process begins when the installation manager requests delivery of the component (Figure 6).  
Onsite installers can request the import of products on schedule through the management system. When the user clicks \"Add Component\" in the import request window and selects the target models in the 3D view, they are added to the request list. The components in the delivery request status are automatically matched with the appropriate vehicle from the system DB, considering the transport schedule and physical characteristics such as the shape, size, weight, and quantity. Subsequently, the management system sends shipping notifications to the driver with the automatically generated invoice. The inventory manager identifies the location and status of the components to be shipped out using the system and completes the final finishing of the product. When the vehicle arrives at the factory, the product is loaded onto it, and the vehicle departs to the site. Installers can share this status in the system in real time. The component delivery is complete when the vehicle arrives at the site and passes through the gate. Product and vehicle information is collected through readers attached to both sides of the gate and then transmitted to the management system. The installer receives the information of the imported products in real time through the system, and the delivery process is completed with the inspection and unloading of the product.  
In the logistics stage, in which the location of the products changes dramatically, management from the JIT perspective is vital. Requests and approvals for transporting components (e.g., production log, receipt request, invoice, and receipt confirmation) must be promptly made. A BIM-based system can effectively implement such request-granting procedures. Because all the information related to a component is managed as a CDM, other information related to one of the properties can be retrieved at any time. In addition, a documentation function is included in the management system to maintain continuity with the existing workflow. In practice, document exchange between business partners through e-mail, fax, and postal mail has different document formats. Using DevExpress's extensive UI control functions optimized for C# and.NET-based environments, a digital form design is established between various customers in the management system. Additionally, the system can retrieve and output only the required information from the model DB, allowing  
Figure 6: UI for shipping request.  
automatic creation of the document. To enable the JIT management of the logistics phase, the proposed management system uses the global positioning system (GPS) technology. Using RFID alone, location tracking can be realized through reception with GPS. Unlike in the factory and onsite environments, in which precise resolution is required because the components are placed close to one another, the positions during transport have a reasonable margin of error. Consequently, the system receives location data from a GPS attached to the vehicle when the component is being transported. These data are stored as sub-attributes for each component.