Source: Proceedings of International Conference on Advances and New Challenges in Earthquake Engineering Research (ICANCEER02), Hong Kong, China, August 19-20, 2002. EMBEDDING ALGORITHMS IN A WIRELESS STRUCTURAL MONITORING SYSTEM Jerome Peter Lynch 1 , Arvind Sundararajan 2 , Kincho H. Law 1 , and Anne S. Kiremidjian 1 1 Department of Civil and Environmental Engineering, Stanford University Stanford, CA, USA 2 Department of Electrical Engineering, Stanford University Stanford, CA, USA ABSTRACT A complex wireless sensing unit is designed for application in structural monitoring systems. Fabricated from advanced embedded system technologies, the prototype unit employs a spread- spectrum wireless modem for peer-to-peer communication between sensing units and a complex 32-bit computational core for local data interrogation. Utilizing the computational capabilities of the sensing unit design, a collection of structural health monitoring software applications can be implemented for execution by the units. Fast Fourier transforms and methods for fitting auto-regressive time-series models are employed as illustrative algorithms embedded in the wireless sensing unit. The research goal is a wireless sensing network supporting the collaborative processing of real-time measurement data for the identification of potential damage in a structural system. INTRODUCTION The field of structural engineering has historically derived tremendous benefit from the installation of structural monitoring systems. Data generated by structural monitoring systems provide insight to the performance of a structure over its operational life and during large external disturbances such as earthquakes. The current state-of-technology is characterized by centralized systems that employ sensors (such as accelerometers) wired to a centralized data acquisition system. The use of wires as the sole medium for data transfer from system sensors to data servers cause systems to have high installation and maintenance costs. As a result, the adoption of the technology is defined as sluggish. With installation and maintenance costs high for tethered systems, Straser (1998) proposed employing wireless communication technology to serve as a cost effective and reliable alternative for current cabled structural monitoring systems. The past decade has witnessed the explosive growth of wireless communications along with major advancements of integrated circuit and embedded system technologies. For wireless communication and embedded system technologies, the cost of hardware components continues to decrease while their functional capabilities broaden. As a result, a wireless sensing unit is designed and constructed from off-the-shelf hardware components to serve as the fundamental building block of wireless modular