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We used high-pass filtering and the Fourier transform to analyze tidal gravity data prior to five earthquakes from four superconducting gravity stations around the world. A stable gravitational perturbation signal is received within a few days before the earthquakes. The gravitational perturbation signal before the Wenchuan earthquake on May 12, 2008 has main frequency of 0.1–0.3 Hz, and the other four have frequency bands of 0.12−0.17 Hz and 0.06−0.085 Hz. For earthquakes in continental and oceanic plate fault zones, gravity anomalies often appear on the superconducting gravimeters away from the epicenter, whereas the stations near the epicenter record small or no anomalies. The results suggest that this kind of gravitational perturbation signals correlate with earthquake occurrence, making them potentially useful earthquake predictors. The far-field effect of the gravitational perturbation signals may reveal the interaction mechanisms of the Earth’s tectonic plates. However, owing to the uneven distribution of gravity tide stations, the results need to be further confirmed in the future.

An adaptive inverse optimal attitude controller for flexible spacecraft with fault-free actuator is designed based on adaptive control Lyapunov function and inverse optimal methodology subjected to unknown parameter uncertainties, external disturbances and input saturation. The partial loss of actuator effectiveness and the additive faults are considered simultaneously to deal with actuator faults, and the prior knowledge of bounds on the effectiveness factors of the actuators is assumed to be unknown. A fault-tolerant control version is designed to handle the system with actuator fault by introducing a parameter update law to estimate the lower bound of the partial loss of actuator effectiveness faults. The proposed fault-tolerant attitude controller ensures robustness and stabilization, and it achieves H∞ optimality with respect to a family of cost functionals. The usefulness of the proposed algorithms is assessed and compared with the conventional approaches through numerical simulations.

The Geological Database Management System is a foundation and an uniform and standard resource platform for tasks of researching, prospecting and mining, which makes those works finished more quickly and efficiently. Unified Modeling Language (UML) is a standard language in software analysis design, which is characterized by strong expression capability and can be used in the whole process of software analysis, design and realization. Taking Web Geological Database Management System as an example, it discusses the relative technologies of UML and the normal frame in system development and application. It also describes the process of modeling of Web Geological Database Management System and the steps to analysis and design in detail based on UML. According those works, the material analysis and design model is created. And finally, it discusses the deficiency of system model and further study aspect.