Unsteady flow fields over a circular cylinder are trained and predicted using four different deep learning networks: generative adversarial networks with and without consideration of conservation laws and convolutional neural networks with and without consideration of conservation laws. Flow fields at future occasions are predicted based on information of flow fields at previous occasions. Predictions of deep learning networks are conducted on flow fields at Reynolds numbers that were not informed during training. Physical loss functions are proposed to explicitly impose information of conservation of mass and momentum to deep learning networks. An adversarial training is applied to extract features of flow dynamics in an unsupervised manner. Effects of the proposed physical loss functions and adversarial training on predicted results are analyzed. Captured and missed flow physics from predictions are also analyzed. Predicted flow fields using deep learning networks are in favorable agreement with flow fields computed by numerical simulations.

Tracks of typhoons are predicted using a generative adversarial network (GAN) with satellite images as inputs. Time series of satellite images of typhoons which occurred in the Korea Peninsula in the past are used to train the neural network. The trained GAN is employed to produce a 6-hour-advance track of a typhoon for which the GAN was not trained. The predicted track image of a typhoon favorably identifies the future location of the typhoon center as well as the deformed cloud structures. Errors between predicted and real typhoon centers are measured quantitatively in kilometers. An averaged error of 95.6 km is achieved for tested 10 typhoons. Predicting sudden changes of the track in westward or northward directions is identified as a challenging task, while the prediction is significantly improved, when velocity fields are employed along with satellite images.

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This paper presents a decentralized adaptive backstepping controller to dampen oscillations and improve the transient stability to parametric uncertainties in multimachine power systems. The proposed design on the i th synchronous generator uses only local information and operates without the need for remote signals from the other generators. The design of the nonlinear controller is based on a modified fourth-order nonlinear model of a synchronous generator, and the automatic voltage regulator model is considered so as to decrease the steady state voltage error. The construction of both the control law and the associated Lyapunov function is systematically designed within the design methodology. A 3-machine power system is used to demonstrate the effectiveness of the proposed controller over two other controllers, namely a conventional damping controller (power system stabilizer) and one designed using the feedback linearization techniques.

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SUMMARYA reliable electricity supply infrastructure is fundamental to modern living. An interruption to electricity services has such far reaching impact to our everyday lives to various industries compared to other service interruptions, thus to build in significant redundancy and various preventive measures to electric power system operation and planning is needed. Just as important as to incorporate redundancy and preventive measures however, an effective restoration plan needs to be in place since the possibility of electricity service interruption cannot be eliminated completely.In this paper, a novel power system restoration plan that utilizes the characteristic of so-called scale-free networks is proposed. For a scale-free network, the importance of each node is determined based on the number of connections made to other nodes in that the nodes with many connections, thus important, are called ''hubs.'' A scale-free network is a special complex network which follows a power law distribution, that is few hubs and many nodes with few connections at various system sizes. In the proposed plan the hubs are restored before other insignificant nodes in the system. It is shown that by doing so, the total restoration time can be reduced considerably, and notable improvements can be achieved with respect to the objective function in the mathematical formulation of electric power system restoration problem with a few constraints introduced in this paper. The effectiveness of proposed plan is tested with one of the planning problems such as valuation of black-start capable generators using IEEE-30 bus system.

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