• Journal of Communications and Networks
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• 제14권6호
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• pp.614-618
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• 2012

Smart grid is widely considered to be a next generation power grid, which will be integrated with information feedback communications.However, smart grid communication technologies are subject to inefficient spectrum allocation problems. Cognitive radio networks can solve the problemof spectrumscarcity by opening the under-utilized licensed bands to secondary users. In this paper, adaptive cognitive radio spectrum sensing and sharing algorithms are developed for smart grid environments. Simulation results are presented to demonstrate the effectiveness of the proposed scheme in comparison with other existing schemes.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.425-434
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• 2020

Practical non-synoptic fluctuating wind often exhibits nonstationary features and should be modeled as nonstationary random processes. Generally, the coherence function of the fluctuating wind field has time-varying characteristics. Some studies have shown that there is a big difference between the fluctuating wind field of the coherent function model with and without time variability. Therefore, it is of significance to simulate nonstationary fluctuating wind field with time-varying coherent function. However, current studies on the numerical simulation of nonstationary fluctuating wind field with time-varying coherence are very limited, and the proposed approaches are usually based on the traditional spectral representation method with low simulation efficiency. Especially, for the simulation of multi-variable wind field of large span structures such as transmission tower-line, not only the simulation is inefficient but also the matrix decomposition may have singularity problem. In this paper, it is proposed to conduct the numerical simulation of nonstationary fluctuating wind field in one-spatial dimension with time-varying coherence based on the wavenumber-frequency spectrum. The simulated multivariable nonstationary wind field with time-varying coherence is transformed into one-dimensional nonstationary random waves in the simulated spatial domain, and the simulation by wavenumber frequency spectrum is derived. So, the proposed simulation method can avoid the complicated Cholesky decomposition. Then, the proper orthogonal decomposition is employed to decompose the time-space dependent evolutionary power spectral density and the Fourier transform of time-varying coherent function, simultaneously, so that the two-dimensional Fast Fourier transform can be applied to further improve the simulation efficiency. Finally, the proposed method is applied to simulate the longitudinal nonstationary fluctuating wind velocity field along the transmission line to illustrate its performances.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제34권2호
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• pp.93-111
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• 2023

The authors investigated the artistic characteristics of autistic savant artists, hypotheses on the proximate and ultimate causes of their emergence, recent psychological and other studies about them, and psychological and neuroaesthetic studies about non-savant autistic individuals. The artistic features of autistic savant artists were significantly similar to those of outsider artists. Furthermore, the authors investigated the explanatory power of the paradoxical functional facilitation theory, the superior visual perception hypothesis, the "Hmmmmm" hypothesis, and the Neanderthal theory of autism regarding the emergence of autistic savant artists. In addition, we investigated whether an increase in savant characteristics was related to a decrease in the ability for social communication. The authors suggested that in studies on the aesthetic experience of non-savant autistic individuals, their aesthetic experience ability is never lower than that of neurotypical individuals and that some non-savant autistic individuals may potentially have artistic talent. Finally, the authors reviewed the effectiveness of the "autism savant spectrum syndromic disorder" proposed by some researchers. More scientific and systematic studies on autistic savant artists from a multidisciplinary perspective are warranted.