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SUMMARYThis paper presents the "rst application of a semi-active damper system to an actual building. The Semi-active Hydraulic Damper (SHD) can produce a maximum damping force of 1000 kN with an electric power of 70 W. It is compact, so a large number of them can be installed in a single building. It is thus possible to control the building's response during a severe earthquake, because a large control force is obtained in comparison with a conventional active control system. This paper outlines the building, the control system con"guration, the SHD, the control method using a Linear Quadratic Regulator, the response analysis results of the controlled building, and the dynamic loading test results of the actual SHD. The simulation analysis shows that damage to building can be prevented in a severe earthquake by SHD control. The dynamic loading test results of the SHD are reported, which show that the speci"ed design values were obtained in the basic characteristic test. The control performance test using simulated response time histories, also shows that the damping force agrees well with the command. Finally, it is con"rmed that the semi-active damper system applied to an actual building e!ectively controls its response in severe earthquakes.

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Ubiquitous structural monitoring (USM) of several decades. In this point of view, a risk monitoring of buildings using wireless sensor networks is one of the most buildings with wireless sensor networks was proposed [2], [3], promising emerging technologies for mitigation of seismic hazard. [4]. The risks for the buildings include not only structural This technology has the potential to change fundamentally the damages, material degradation, fatigue and corrosion of metals, traditional monitoring systems. This paper provides an but also invasion, gas leaks, fires, and others. By using introduction of wireless sensor network technology for USM, and wireless sensor networks, high density distributed sensing for identifies some of opportunities and associated challenges.all of the risks in the building could be realized and the

In this paper we present a high-density earthquake monitoring system using wireless sensor networks. For highprecision monitoring, we developed Pavenet OS, which is a hard-realtime operating system for sensor nodes, and acceleration sensor board. Sensor nodes of the system sample acceleration with less than 0.3 us jitter with Pavenet OS. The system provides earthquake engineering researchers the ability to measure vibrations of structures during earthquakes at less cost and higher node density than previous systems.