Search

The interconnection of multiple microgrids can effectively improve the operating efficiency of the system and reduce the cost of power generation. First, establish an economic environment optimal dispatch model based on the regional interconnected multi‐microgrids system, and formulate a dispatch strategy based on the time‐of‐use electricity price and the supply‐demand relationship between microgrids; Secondly, in order to solve this constrained optimization problem, a whale algorithm improved with five strategies including adaptive inertial weights, dynamic spiral search and generalized opposition‐based learning is proposed to obtain higher solution accuracy and anti‐premature convergence ability; Finally, combined 12 test functions to test the effectiveness of the improved algorithm, and use the improved algorithm to solve the example model containing two microgrids, and analyze it in two states of interconnection operation and non‐interconnection operation. The simulation results show that the regional interconnection operation of the microgrid under the established dispatching strategy can effectively reduce the overall operating cost of the system, and at the same time show the effectiveness of the improved algorithm to solve the optimal dispatching problem. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The reproducibility of precipitation in the early stages of forecasts, often called a spindown or spinup problem, has been a significant issue in numerical weather prediction. This problem is caused by moisture imbalance in the analysis data, and in the case of the Japan Meteorological Agency's (JMA's) mesoscale data assimilation system, JNoVA, we found that the imbalance stems from the existence of unrealistic supersaturated states in the minimal solution of the cost function in JNoVA. Based on the theory of constrained optimization problems, we implemented an exterior penalty function method for the mixing ratio within JNoVA to suppress unrealistic supersaturated states. The advantage of this method is the simplicity of its theory and implementation. The results of twin data assimilation cycle experiments conducted for the heavy rain event of July 2018 over Japan show that—with the new method—unrealistic supersaturated states are reduced successfully, negative temperature bias to the observations is alleviated, and a sharper distribution of the mixing ratio is obtained. These changes help to initiate the development of convection at the proper location and improve the fractions skill score (FSS) of precipitation in the early stages of the forecast. From these results, we conclude that the initial shock caused by moisture imbalance is mitigated by implementing the penalty function method, and the new moisture balance has a positive impact on the reproducibility of precipitation in the early stages of forecasts. [ABSTRACT FROM AUTHOR]

We determine an updated model of P - and S- wave attenuation (Qp, Qs) tomography of the Japan subduction zone using an improved inversion scheme, and derive the first Qp / Qs model of the study region. We establish a system of observation t * equations by taking 1/ Q values at 3-D grid nodes arranged in the study volume as unknown parameters. This scheme can eliminate model errors caused by ignoring high-order terms of the Taylor expansion in the Q -format scheme adopted by previous studies. The inversion problem is considered as a quadratic programming problem with bound constraints for best fitting the observed t * data in a least-squares sense. The 3-D attenuation model is obtained by using a limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm for bound constrained optimization. Because this inversion scheme uses bound constraints to avoid negative Q values, damping regularization is not needed, hence the ranges of Qp and Qs values obtained are less affected by human subjectivity. The subducting Pacific and Philippine Sea slabs exhibit high- Q and high Qp / Qs , whereas the mantle wedge beneath the volcanic front and back-arc area shows low- Q and low Qp / Qs. Both Qp and Qs vary in a range of 10–2000, and the Q p/ Q s ratio changes from 0.4 to 1.4. Our results reveal a narrow high- Qp / Qs belt that is coincident with the distribution of volcanic and non-volcanic low-frequency micro-earthquakes (M 0.0–2.5), which may reflect high water-saturation anomalies that are probably associated with slab-derived fluids and responsible for the generation of low-frequency micro-earthquakes. [ABSTRACT FROM AUTHOR]

The article considers optimization of mixed constraints for a controlled system that describes countrylevel economic growth driven by technological progress. An algorithm is proposed, reducing this problem to an equivalent general optimization problem in a normed space, which in turn is solved by an iterative method based on N. N. Krasovskii's extremal shift method. Calculation results are reported for the economy of Japan in the second half of the twentieth century. [ABSTRACT FROM AUTHOR]