Smart lock services span a wide range of technical fields, including IoT devices, the cloud, and smartphone apps. When developing a derivative of such a system, it is important to request changes in each area, requests for additional functions, and cooperation between areas in order to realize the service vision. Therefore, we used the concept of XDDP to communicate in each area using modified USDM and a traceability matrix. As a result, we were able to complete development in half a year and begin actual operation in eight months. In this lecture, we will introduce the usefulness of USDM in derivative development in a wide range of technical areas, and examples of ultra-short-term service development and operation that were realized through planning management and communication innovations.