• 디지털산업정보학회논문지
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• 제4권1호
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• pp.17-24
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• 2008

This paper describes the measurements that provide a characterization of the code-domain channels of a CDMA base station transmitter. One of the measurements, called code-domain power(CDP), provides the distribution of power in the code domain channels. This measurement can be used to verify that the various channels are at expected power levels and to determine when one code channel is leaking energy into the other code channels. We develop module of CDP measurement in the CDMA system.

• 대한수학회보
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• 제55권4호
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• pp.1007-1012
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• 2018

Let R be an integral domain. We prove that the power series ring R[[X]] is a Krull domain if and only if R[[X]] is a generalized Krull domain and t-dim $R{\leq}1$, which improves a well-known result of Paran and Temkin. As a consequence we show that one of the following statements holds: (1) the concepts "Krull domain" and "generalized Krull domain" are the same in power series rings, (2) there exists a non-t-SFT domain R with t-dim R > 1 such that t-dim R[[X]] = 1.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.208-220
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• 2017

This paper proposes an experimental optimization method for a wireless power transfer (WPT) system. The power transfer characteristics of a WPT system with arbitrary loads and various types of coupling and compensation networks can be extracted by frequency domain measurements. The various performance parameters of the WPT system, such as input real/imaginary/apparent power, power factor, efficiency, output power and voltage gain, can be accurately extracted in a frequency domain by a single passive measurement. Subsequently, the design parameters can be efficiently tuned by separating the overall design steps into two parts. The extracted performance parameters of the WPT system were validated with time-domain experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.489-493
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• 2007

Mmulti-domain noise analysis method using Power Flow Boundary Element Method(PFBEM) has been developed successfully. Some applications are introduced. several examples. PFBEM is a numerical analysis method formulated by applying Boundary Element Method(BEM) to Power Flow Analysis(PFA). PFBEM is very powerful in predicting noise level in medium-to-high frequency ranges. However there are restrictions in analyzing the coupled structures and multi-media. In this paper, an analysis method for multi-domain acoustic problems in the diverse acoustic fields is suggested. And the developed method is applied to the car interior and exterior multi-domain noise analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.469-470
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• 2007

There are many power system simulation software tools for time-domain performance in power system. This paper reports the results of time-domain simulation for the Jeju Power system with a secondary voltage regulation (SVR) model, developed with both TSAT and PSCAD/EMTDC and evaluates them, which are commercial software tools used for digital simulation of power system. TSAT has not been yet verified because of deficient modelling of components in the time domain performance of KEPCO power system. But PSCAD/EMTDC has been enough verified in our system. So, we need to compare and evaluate TSAT with PSCAD/EMTDC in small power system like Jeju. This paper showed that the results simulated by both TSAT and PSCAD/EMTDC is very similar to each other, so TSAT is able to apply for our KEPCO large power system.

• 전기학회논문지P
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• 제66권4호
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• pp.247-251
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• 2017

This paper proposes a low power transmission technique for single-carrier modulation with frequency domain equalization. As time domain signals and frequency domain signals have unique corresponding functions, inserting zeros after each symbol causes a repetition in other domain, so maximal ratio combining technique using repetitive transmission can be applied in the frequency domain. In this paper, we configure transmit signals to insert zeros after each symbols for single-carrier modulation with frequency domain equalization and maximal ratio receive combining block in the receiver structures, propose a structure for transmitter and receiver and show that its performance is better than the traditional algorithm by simulations.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.209-212
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• 2002

본 논문은 W-CDMA 무선 채널의 특성 중 Code domain을 분석을 하기 위한 시스템구현이다. 시스템 구성은 크게 RF부와 FPGA부, DSP부로 구성이 된다. FPGA는 RF부를 통한 신호를 I/Q분리 및 scambling code를 계산한다. DSP는 scambling code에 의한 역 확산된 신호는 OVSF코드를 이용하여 코드 영역의 전력을 계산을 한다. 실험 및 성능 테스트로는 W-CDMA발생기에 의한 실험 결과 Code domain power 측정 정확도가 $\pm$1dB 이내의 분석이 가능하였다.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.12-18
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• 2001

Frequency domain has been used to detect chatter vibration and to decide commencing point of chatter for the milling processes. For this, power spectrum of accelerations signal is analyzed in the frequency domain. Also, the power spectrum and surface roughness are measured, compared, and evaluated according to the depth of cut by experimental works. As a results, it is known that the commencing point of chatter can be decided the behavior of the maximum amplitude of the power spectrum of acceleration signal and there is a correlation between the power spectrum of acceleration signal and the surface roughness. In conclusion, the power spectrum of acceleration signal can be used as a useful information for detec-tion and estimation of chatter vibration in machining.

• 전력전자학회논문지
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• 제24권3호
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• pp.207-214
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• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.266-268
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• 2006

Power tracking은 발전기가 생산하는 전력의 흐름을 추적함으로써 특정 발전기가 특정 부하에 공급하는 전력의 양, 측정 송전선 점유율, 계통손실에 기여량 등을 결정할 수 있게 해준다. 본 논문에서는 loop화되어 있는 실계통을 여러 domain으로 나누고 하나의 domain 또는 중첩된 domain 간의 교류송전선의 대체 안으로 FACTS나 HVDC과 같은 active 소자의 설치위치를 선정하기 위해 power tracking을 이용하였으며 이를 효과적으로 시각화 하기위한 프로그램을 개발하였다.