• Journal of Communications and Networks
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• 제14권1호
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• pp.27-33
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• 2012

In this paper, a new blind signal processing scheme for equalization in fading and impulsive-noise channel environments is introduced based on probability density functionmatching method and a set of Dirac-delta functions. Gaussian kernel of the proposed blind algorithm has the effect of cutting out the outliers on the difference between the desired level values and impulse-infected outputs. And also the proposed algorithm has relatively less sensitivity to channel eigenvalue ratio and has reduced computational complexity compared to the recently introduced correntropy algorithm. According to these characteristics, simulation results show that the proposed blind algorithm produces superior performance in multi-path communication channels corrupted with impulsive noise.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.387-394
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• 2005

This paper deals with the grid-interactive small battery energy storage system, which aims at the integration o( power quality improvement and demand side management. The main purpose of the proposed system is to achieve the peak power cutting and to compensate the current harmonics and reactive power at the point of installation on power distribution for residential homes. paper deals with the grid-interactive small battery energy storage system, In this paper, the basic principle and control algorithm is analyzed, theoretically and the design methodology of the system is discussed. To verify the proposed system, a comprehensive evaluation with theoretical analysis, simulation and experimental results for 1 KVA load capacity is presented.

• 전기학회논문지
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• 제58권10호
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• pp.1895-1901
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• 2009

This paper describes the conductor temperature and tensile load analysis of invar by flame exposure on STACIR(Super Thermal-resistance Aluminium-alloy Conductors Reinforced) overhead transmission line based on real fault phenomena. Firstly, short-circuit fault by flame exposure is analysed by EMTP/ATP simulation, then the cutting causes of Al layer are also discussed. And then, the conductor temperature is calculated based on IEC 60949 according to 3 kinds of materials including invar, Al conductor and ACSR when same load current respectively flows in 3 kinds of material, they are compared each other. Finally, the tensile load tests are performed with various samples including new invar, used invar for a long time and invar exposed flame.

• 전기학회논문지
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• 제66권6호
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• pp.923-926
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• 2017

In this study, a novel wideband conformal thin antenna is presented for endoscopic capsule application at the 915 MHz Industrial, Scientific and Medical (ISM) band. The thickness of the antenna is only 0.2 mm which can be wrapped inside a capsule's inner wall. By cutting meandered slots on patch, open end slots on ground and utilizing long arm, the proposed antenna can obtain significant size reduction. The net volume of the proposed antenna including substrate and superstrate is only $37.4mm^3$ ($187mm^2$ surface area). This conformal antenna has shown good performance through simulation and measurement with maximum gain of -23 dBi and wide bandwidth from 137 MHz - 205 MHz depending on different environment. In addition, the effect of internal materials specially metallic battery is discussed briefly.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.973-976
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• 2009

디지털 신호처리 기술은 통신을 비롯한 다양한 분야에서 이용되고 있으며, 이러한 신호처리를 위해 사용되는 대표적인 필터에는 FIR 디지털 필터가 있다. 그리고 FIR 디지털 필터를 설계함에 있어서, 이상적인 필터에 대한 계수 절단 과정에서 발생하는 깁스현상(Gibbs phenomenon)을 감소시키기 위해, 창함수를 사용한다. 따라서, 본 논문에서는 디지털 필터의 성능을 향상시키기 위해, 고차의 창함수를 적용하였으며, 시뮬레이션에서 최대부엽의 크기와 천이 특성을 이용하여 기존의 창함수와 비교하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.66-71
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• 2008

Two cases with circumferential grooves were designed for a transonic compressor, and 3-D numerical simulations were conducted for stall mechanism at three representative speeds. A conclusion can be drawn from the comparison between compressors with or without casing treatment that: with the rising of rotation speed, stall margin increases dramatically under the help of casing treatments, and the case with middle grooves has reasonable compromise between stall margin increment and efficiency cutting. At lower speed, the increment reduces, and grooves at the back of blade tip have more influence on stall margin. Further investigation shows there is a transition in mechanism of compressor stall with the decline of rotational speed: at high rotation speed, the expansion of stall margin mainly results from the suppression of tip leakage vortex by casing treatments, yet it benefits more from the depression of boundary layer separation from suction surface of blade tip.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.1-13
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• 1995

Vortex shedding from a circular cylinder is simulated by means of the discrete vortex method. The shear layer emanating from the separation point is approximated as a sheet vortex which is in turn represented by a sequence of discrete vortices. The strength of these vortices is calculated from the vorticity shedding rate and introduced at a small distance off the side ($\Theta=\pm\pi/2$) of the cylinder surface in regular time step. Sheet vortex cutting, rediscretization and replacement of vortex by vortex segment are put to use to enhance stability of the sheet vortex evolution. The simulated vortex distribution pattern very well reproduces structure like the Karman vortex street. However, as for the force coefficients, the qualitative properties are correctly predicted but some more improvements are needed for the quantitative accuracy.

• ETRI Journal
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• 제41권2호
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• pp.160-166
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• 2019

A novel analytical method based on the cavity mode theory to design a metasurface (MS) is proposed in this study. We carefully analyzed the phase and amplitude characteristics of the incident wave and transmitted wave, and successfully designed a circular polarization conversion MS by introducing a cutting structure with wider operation bandwidth and higher radiation direction gain compared with that of the original MS. For the measurements, a microstrip antenna operating at 2.4 GHz was used as the source antenna to verify the designed MS. The simulation and measurement results agree well with each other.

• International journal of advanced smart convergence
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• 제13권2호
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• pp.7-15
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• 2024

6G network technology represents the next generation of communications, supporting high-speed connectivity, ultra-low latency, and integration with cutting-edge technologies, such as the Internet of Things (IoT), virtual reality, and autonomous vehicles. These advancements promise to drive transformative changes in digital society. However, as technology progresses, the demand for efficient data transmission and energy management between smart devices and network equipment also intensifies. A significant challenge within 6G networks is the optimization of interactions between satellites and smart devices. This study addresses this issue by introducing a new game theory-based technique aimed at minimizing system-wide energy consumption and latency. The proposed technique reduces the processing load on smart devices and optimizes the offloading decision ratio to effectively utilize the resources of Low-Earth Orbit (LEO) satellites. Simulation results demonstrate that the proposed technique achieves a 30% reduction in energy consumption and a 40% improvement in latency compared to existing methods, thereby significantly enhancing performance.

• Coupled systems mechanics
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• 제13권3호
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• pp.219-229
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• 2024

By introducing optimization algorithms into the machining process, product quality can be improved, time saved, and costs reduced. The cutting speed and feed can be handled by the turning machine. The approach of optimizing is used to manage pyrotechnics, Lawler's, greedy, bacterial colony, elephant herding, ant lion, spiral, auction, and pattern search for these ten odd ways. Ten artificial optimization methodologies were used to investigate the time and cost of a turning machine. It has been discovered how to create the optimal turning machine procedure. The best solution approach for the turning machine process problem is found, and the results are verified using ANSYS.