Land is an essential resource for economic and social development. Land resources investigation is important yet quite challenging. Geospatial technologies such as remote sensing (RS), global positioning system (GPS), and geographic information systems (GIS) have been utilized to support the second national land resources survey initiated by the Chinese central government since 2007. In this paper, we analyze the feasibility of using the remote sensing technology to support the second land resources survey and discuss the method of processing and interpreting remotely sensed data.
We conclude that the remote sensing technology is critical to the completion of the second national land resources survey.
The essence of AMD controller based on the fixed-base structure to control SSI system is interpreted, firstly. Then the
applicability of AMD controller based on fixed-base structure to control SSI system is studied through simulation
analysis using LQR algorithm. The results show that the AMD controller designed based on the fixed-base structure can
control SSI system effectively when the ratio of the frequencies of the SSI system and the fixed-base structure ωs / ωr is
larger than 0.9. However, when s ωs / ωr is smaller than 0.4 this kind controller is not suitable to control SSI system.
Finally, the shaking table tests about AMD control SSI system built on three kinds of soil parameters are carried out
using four kinds AMD controllers. Tests result that while the soil foundation is stiff enough the controllers work very
effectively, while the soil foundation is soft the controllers can't control the response of SSI system even make larger
deformation and acceleration of the structure. The test results further validate the conclusion of simulation analysis.
In this paper, a LQG controller based on the finite element model of SSI system is established to optimally control the
responses of SSI system. Substructuring analysis is used to reduce the system into a smaller set of DOFs system to
design the active controller, which includes the complete informations of SSI system. Furthermore, the influence of the
boundary condition and the depth of soil layer on control effectiveness are investigated using the proposed method. The
results show that different boundary conditions can get almost same control effectiveness, but depth of soil layer will
influence the control effectiveness. Finally, the standard two-floor shear structure with SSI effects used as the model, and
AMD controller strategy designed based on the proposed method is validated through a serial of shaking table tests,
which further verify the proposed method, results show that the proposed method can more effectively control the
responses of SSI system than that designed based on the lump-parameter model does.
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