• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.257-261
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• 2008

The Digital Radio Mondiale (DRM) system is a digital broadcasting standard designed for use in the LF, MF and HF bands of the broadcasting bands below 30 MHz. The system provides both superior audio quality and improved user services / operability compared with existing AM transmissions. In this paper, we propose a variable point Prime Factor FFT design method for Digital Radio Mondiale (DRM) system. Proposed method processes a various size IFFT/FFT of Robustness Mode on DRM standard efficiently by composing Radix-Prime Factor FFT Processing Unit of form similar to Radix-4 by insertion of a variable Prime Factor Twiddle Factor and Garbage data. So, we improved limitation that cannot process 112/176/256/288 FFT of each mode of DRM system with a existent Radix Processor and increase memory size and memory access time for IFFT/FFT processing by software processing in case of implementation with a existent high speed DSP.

• 대한간호학회지
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• 제43권5호
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• pp.587-594
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• 2013

Purpose: The purpose of this study is to provide researchers with a simplified approach to undertaking exploratory factor analysis for the assessment of construct validity. Methods: All articles published in 2010, 2011, and 2012 in Journal of Korean Academy of Nursing were reviewed and other relevant books and articles were chosen for the review. Results: In this paper, the following were discussed: preliminary analysis process of exploratory factor analysis to examine the sample size, distribution of measured variables, correlation coefficient, and results of KMO measure and Bartlett's test of sphericity. In addition, other areas to be considered in using factor analysis are discussed, including determination of the number of factors, the choice of rotation method or extraction method of the factor structure, and the interpretation of the factor loadings and explained variance. Conclusion: Content validity is the degree to which elements of an assessment instrument are relevant to and representative of the targeted construct for a particular assessment purpose. This measurement is difficult and challenging and takes a lot of time. Factor analysis is considered one of the strongest approaches to establishing construct validity and is the most commonly used method for establishing construct validity measured by an instrument.

• 한국도로학회논문집
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• 제15권3호
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• pp.103-115
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• 2013

PURPOSES: The purpose of this study is to develop a method for distribution between superelevation and side friction factor by increasing design speed. METHODS: First of all, a method for distribution between superelevation and side friction factor and a theory for the functional formula of side friction factor in compliance with horizontal radius applied in South Korea and the United States are considered. Especially, design speed of 140km/h and numerical value of design elements are applied to the theory for the functional formula of side friction factor in AASHTO's methods. Also, the anxiety EEG upon running speed is measured to reflect ergonomic characteristics through field experiments at seven curve sections of the West Coast Freeway, and this data is applied to graph for the functional formula of side friction factor. RESULTS : Matching side friction factor against the anxiety EEG, the results that a critical points of driver's anxiety EEG sharply increase locate under existing parabola are figured out. CONCLUSIONS : Therefore, we could get a new type of the functional formula that driver's driving comfortability is guaranteed if the existing the functional formula of side friction factor goes down under boundary of the critical points of the anxiety EEG.

• 한국지구과학회지
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• 제37권5호
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• pp.277-285
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• 2016

We introduce a depth scaling strategy to improve the accuracy of frequency-domain elastic full waveform inversion (FWI) using the new pseudo-Hessian matrix for seismic data without low-frequency components. The depth scaling strategy is based on the fact that the damping factor in the Levenberg-Marquardt method controls the energy concentration in the gradient. In other words, a large damping factor makes the Levenberg-Marquardt method similar to the steepest-descent method, by which shallow structures are mainly recovered. With a small damping factor, the Levenberg-Marquardt method becomes similar to the Gauss-Newton methods by which we can resolve deep structures as well as shallow structures. In our depth scaling strategy, a large damping factor is used in the early stage and then decreases automatically with the trend of error as the iteration goes on. With the depth scaling strategy, we can gradually move the parameter-searching region from shallow to deep parts. This flexible damping factor plays a role in retarding the model parameter update for shallow parts and mainly inverting deeper parts in the later stage of inversion. By doing so, we can improve deep parts in inversion results. The depth scaling strategy is applied to synthetic data without lowfrequency components for a modified version of the SEG/EAGE overthrust model. Numerical examples show that the flexible damping factor yields better results than the constant damping factor when reliable low-frequency components are missing.

• 대한공간정보학회지
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• 제19권4호
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• pp.139-144
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• 2011

본 연구는 지상라이다 자료에서 얻어진 색상정보(R, G, B)와 반사강도정보(I)를 동시에 이용하여 이를 통계학적 분류기법으로 서로의 연관성을 분석하여 라이다 자료에 대한 분류방법을 제시하였다. 이를 위하여 우선 변수 R,G,B 및 I를 사용하여 분산 을 극대화하는 요인을 추출하여 주요인과 각 변수들 간의 요인행렬을 산출하였다. 그러나 요인행렬은 기초자료를 축소시켜 보여주기는 하지만, 이로부터 어떤 변수들이 어떤 요인에 의해 높게 관계되는지 명확하게 알기 어렵기 때문에 직각회전방식 중에서 Varimax방법을 이용하여 회전된 요인행렬을 구하여 요인점수를 산출하였다. 그리고 비 계층적 군집화 방법인 K-평균법을 이용하여 요인분석으로 산출된 요인점수에 대하여 군집분석을 실시한 후, 지상라이다 자료의 분류 정확도를 평가하였다.

• 전자공학회논문지
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• 제53권7호
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• pp.121-127
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• 2016

본 논문에서는 고조파로 전압과 전류가 왜곡된 상황에서 정확하게 기본파의 역률을 측정할 수 있는 방법을 제안한다. 제안한 역률 계측 방법에서는 전압과 전류를 DQ회전좌표계로 변환한 후 유효전력과 무효전력을 계산하여 역률값을 구하게 된다. 기존의 역률 계측방법과 제안한 방법을 수식적으로 비교하여 제시하고, 제안한 방법은 전압과 전류 모두 고조파 왜곡된 상황에서도 기본파의 역률을 정확하게 계측할 수 있는 것을 MATLAB을 이용한 모의실험에서 확인한다. 제안한 역률 계측방법을 자동역률제어장치에 적용할 경우 고조파 왜곡 환경에서 역률 보상 성능을 최대화 할 수 있다. 그 결과 수용가에서는 역률 개선을 통한 전기료 감소, 선로손실 감소, 부하 용량 증대 효과가 기대된다. 특히 발전 사업가 측에서는 역률 보상 성능의 향상으로 송전 여유 용량 확보와 발전량 절감이 가능하다.

• 한국초등과학교육학회지:초등과학교육
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• 제37권1호
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• pp.1-11
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• 2018

Factors and causal structures of pre-service elementary teachers about the critical thinking and the scientific literacy competency were investigated in this study. The third grade university students and the first grade university students in the metropolitan city participated in this study. The factor analysis method and the structural equation modeling method were used for the data analysis, and the following results were obtained. First, the third grade university students and the first grade university students recognized 'inquisitive thinking' factor and 'reflective thinking' factor as factors of the critical thinking, and 'scientific explanation' factor and 'evidence-based conclusion' factor as factors of the scientific literacy competency respectively. Second, the third grade university students showed more the influence from 'reflective thinking' factor to 'scientific explanation' factor and from 'reflective thinking' factor to 'evidence-based conclusion' factor than the first grade university students.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.237-240
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• 2000

A new control method using average comparison strategy have been proposed in this paper. This control method realizes sinusoidal input and output current. unity input displacement factor regardless of load power factor. Moreover compensation of the asymmetrical and harmonic containing input voltage is sautomatically realized and calculation time of control function is reduced.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.67-79
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• 1998

Inthe study, a method to evaluate the door closing sound has been developed. Based on the factor analysis, various adjective pairs which describe meaning of the door impact sound have been differentiated. This approach, called Semantic difference(SD) method, was originally developed in linguistics research on order to compare diverse mother tongue. This paper introduces at first how the door sound os generated and transmitted. After that, a factor analysis which is a tool of SD method is implemented to door closing sound for 12 domestic and 1 foreign car models. During investigation, the examined models are categorized into small, medium and luxurious size automobiles. The adjective pairs which attritbute to the door quality have been factorized into three group : expensive/ smooth, powerful/ heavy, and modern/dull. It turns out that the first factor : expensive/ smooth plays the most important role in door closing sound quality.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2359-2364
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• 2017

This paper proposes a scale factor based range estimation method using a sum of squares (SOS) method. Many previous studies measured distance by using a camera, which usually required two cameras and a long computation time for image processing. To overcome these disadvantages, we propose a range estimation method for an object using a single moving camera. A SOS-based Luenberger observer is proposed to estimate the range on the basis of the Euclidean geometry of the object. By using a scale factor, the proposed method can realize a faster operation speed compared with the previous methods. The validity of the proposed method is verified through simulation results.