Masato Yamaji

Wireless sensor network for industrial automation

We have been developing wireless communication technologies for industrial applications. In industrial plants, there are many radio obstacles such as metal pipes and walls. Even in the severe environment, wireless communication has to be reliable and time has to be scheduled to maintain plant stability. For easy-to-use management, features of ad-hoc construction and low power management are also required. Our research is to develop architecture and technologies that satisfy these features. In this demonstration, we will explain core technologies and industrial applications that we developed.

Identifying and verifying clock synchronization protocol parameters

The Internet of Things(IoT) is a novel paradigm, where things are in the majority position of producers and consumers of traffic. IoT is expected to have a strong impact on our everyday life, i.e., the physical space around us. In the physical space, the notion of time is so universal that the information there is often combined with timestamps. To make them consistent among IoT nodes, applications need a clock synchronization mechanism, which has been an important topic in the research community. Whereas earlier studies focused mainly on improving synchronization accuracy, we focus on improving efficiency to achieve a given synchronization accuracy in a given environment. This viewpoint is important because applications do not always require the best synchronization accuracy and only limited resources are available for IoT nodes. We propose methods to identify and verify appropriate parameters for clock synchronization protocols. Because our methods are not limited to a specific protocol, we introduce a clock synchronization protocol model that generalizes a class of clock synchronization protocols and discuss our methods based on it. Our methods are demonstrated on a trace of time information collected in our testbed.