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In this paper, we propose a modified Lipschitz optimization (LO) method and apply it to maximum power point tracking (MPPT) control for photovoltaic (PV) systems. The standard LO can find a global maximum of a Lipschitz continuous function over a closed interval in a deterministic way. However, the standard LO tends to evaluate low objective function values, and this feature leads to low MPPT efficiency in its application to MPPT control. The proposed method skips the evaluation of low objective function values (i.e., low power points) by using prior information on the output characteristics of a PV array. Moreover, we show theoretically that the proposed method guarantees convergence to a global optimal solution. We compare the proposed method with some of well‐known MPPT methods and verify its effectiveness through simulations. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This article investigates the path‐following control problem of an unmanned surface vessel in the presence of uncertainties with only two inputs available (surge force and yaw moment). The problem consists of steering a vessel to follow a scheduled path with the desired velocity assignment. The backstepping technique and Lyapunov's direct method are employed as the main framework to design a controller. To ensure the design requirements, an improved integral line‐of‐sight guidance law is utilized first to calculate the desired yaw angle and to make compensation for the ocean currents based on the reduced‐order linear extended state observer. Then, a controller based on the radial basis function neural network is used to accomplish the yaw angle and velocity tracking, which alleviates the effects of model uncertainties and external disturbances. All the tracking error signals of the closed‐loop system are proved to be uniformly ultimately bounded. It demonstrates that the proposed path‐following control approach can deal well with time‐varying ocean currents, model uncertainties, and time‐varying disturbances. Results of the simulations validate the effectiveness and robustness of the proposed approach. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Series of earthquakes including three M > 6 earthquakes occurred in Kumamoto prefecture in the middle of the Kyushu island, Japan. In order to reveal the associated crustal deformation signals, we applied offset tracking technique to ALOS-2/PALSAR-2 data covering three M > 6 earthquakes and derived the 3D displacements around the epicenters. We could identify three NE-SW trending displacement discontinuities in the 3D displacements that were consistent with the surface location of Futagawa and Hinagu fault system. We set three-segment fault model whose positions matched the displacement discontinuities, and estimated the slip distributions on each segment from the observed pixel-offset data. Whereas right-lateral slip was dominant in the shallower depth of the larger segments, normal fault slip was more significant at a greater depth of the other segment. The inferred configuration and slip distribution of each segment suggest that slip partitioning under oblique extension stress regime took place during the 2016 Kumamoto earthquake sequence. Moreover, given the consistent focal mechanisms derived from both the slip distribution model and seismology, the significant non-double couple components in the focal mechanism of the main shock are due to simultaneous ruptures of both strike-slip and normal faulting at the distinct segments. [ABSTRACT FROM AUTHOR]