• 대한인간공학회지
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• 제32권5호
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• pp.449-457
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• 2013

Objective: The aim of this study is to investigate the effect of Hangul font on reading speed when texts are displayed on the computer screen. Background: Reading performance is influenced by fonts. However, there are few studies of Hangul font from a cognitive perspective. Fonts could affect reading performance directly and indirectly, interacting with other visual-perceptual factors such as size, word spacing, and line spacing. Method: In experiment 1, two variables were manipulated; a frame condition(square frame non-square frame) and a stroke condition(serif sans-serif). According to each condition, one of the four fonts was applied to the texts. The height of the four fonts was controlled. The participants were asked to read aloud the presented texts. In experiment 2, the non-square frame fonts were adjusted to have approximately the same size, width, letter spacing, and word spacing as the square frame fonts. The experimental design and task used in experiment 2 were identical with experiment 1. Results: In general, reading speed was faster in the square frame fonts than in the non-square frame fonts. The reading speed was not significantly different across stroke conditions. Conclusion: The frame of Hangul font significantly influenced reading speed. These results suggest that the type of Hangul font is a factor to affect reading performance. Application: The frame of fonts should be considered in designing of new fonts. The square frame fonts should be the preferred choice to enhance legibility.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2200-2206
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• 2008

This paper describes the results of experiments on the bending behavior of welded square tube structures for drive shaft sub frame of BIMODAL Tram. The used specimens to test were two different type made of ATOS60 and ST52-3. The square tube made of ST52-3 is the non-welded structure, while the square tube made of ATOS60 is the welded structure. The welded square tube made of ATOS60 will be applied for drive shaft sub frame of BIMODAL Tram. This welded square tube could reduce the manufacturing cost in comparison of non-welded square tube. The results showed that the bending performance of welded square tube made of ATOS60 was proven, and the bending behavior was in an good agreement with that of nonlinear finite element analysis.

• 한국전기전자재료학회논문지
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• 제24권9호
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• pp.733-738
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• 2011

A novel design of a simple square-frame USM (ultrasonic motor) was proposed. The stator of the motor consists of a square-frame shape elastic body and four rectangular plate ceramics. The four ceramics were attached to inner surfaces of the square frame elastic body. The same phase voltages were applied to the ceramics on horizontal surfaces, and 90 degree phase difference voltage were applied to the ceramics on vertical surfaces. To find a model that generates elliptical motion at outside of the stator, the finite element analysis program ATILA was used. The analyzed results were compared to the experimental results. As result, the model EL10EH3ET0.5CL4 which generates the maximum elliptical displacement was chosen by analyzing the resonance mode according to changes in frequency.

• 디지털융복합연구
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• 제11권7호
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• pp.135-140
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• 2013

잡음 추정과 검출 알고리즘에서는 LMS Filter를 이용하여 변화하는 잡음 환경에 빠르게 적응할 수 있도록 한다. 하지만 LMS Filter는 잡음 추정을 위한 일정 시간 동안 적응 시간이 필요하며 신호의 변화가 일어날 경우 더 많은 적응 시간이 소요되는 단점을 가지고 있다. 따라서 이를 보완하기 위하여 프레임 단위의 AELMS Filter를 이용한 잡음 제거 방법을 제안한다. 본 논문은 잡음 환경에서 입력되는 신호를 프레임 단위로 분할하고 평균과 분산을 이용한 예측 LMS Filter를 구성하여 잡음을 제거하므로 잡음 환경이 변화하더라도 빠른 적응 시간으로 잡음을 제거한다. 또한 환경 잡음과 음성 신호가 혼합되어 입력될 때 잡음을 제거하여 음성의 고유 특성을 유지하고 음성 정보 손상을 줄이기 위한 방법이다. 프레임 단위의 AELMS Filter를 이용한 잡음 제거 방법으로 잡음 제거 성능을 평가하였다. 실험 결과 변화하는 환경 잡음을 제거하여 얻은 감쇠도가 평균 6.8dB 향상되었다.

• 전력전자학회논문지
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• 제21권3호
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• pp.215-223
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• 2016

In this study, a novel rotor position sensorless estimation method of an interior permanent-magnet synchronous motor is proposed. A square-wave pulsating voltage signal is injected in the estimated synchronous reference frame. This signal is interpreted in the stationary reference frame regardless of the estimated rotor position. Thus, assuming that the position error is nearly zero is unnecessary because the variables in the estimated synchronous reference frame are not used. The rotor position can be exactly calculated from two voltage references and three sampled current feedbacks in the stationary reference frame. The proposed method is easy to implement and helps enhance the bandwidth of the current controller. The validity of the proposed method is verified by simulations and experiments.

• International Journal of Automotive Technology
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• 제8권1호
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• pp.93-102
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• 2007

The frontal crash optimization of an engine room member using the response surface method was studied. The engine room member is composed of the front side member and the sub-frame. The thicknesses of the panels on the front side member and the sub-frame were selected as the design variables. The purpose of the optimization was to reduce the weight of the structure, under the constraint that the objective quantity of crash energy is absorbed. The response surface method was used to approximate the crash behavior in mathematical form for optimization procedure. To research the effect of the regression method, two different methodologies were used in constructing the response surface model, the least square method and the moving least square method. The optimum with the two methods was verified by the simulation result. The precision of the surrogate model affected the optimal design. The moving least square method showed better approximation than the least square method. In addition to the deterministic optimization, the reliability-based design optimization using the response surface method was executed to examine the effect of uncertainties in design variables. The requirement for reliability made the optimal structure be heavier than the result of the deterministic optimization. Compared with the deterministic optimum, the optimal design using the reliability-based design optimization showed higher crash energy absorption and little probability of failure in achieving the objective.

• 한국전자통신학회논문지
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• 제12권6호
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• pp.1115-1120
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• 2017

본 논문에서는 다중경로 페이딩의 무인기 채널환경에서 무인기 속도에 따른 도플러 영향을 극복하기 위해 LMMSE(: Linear Minimum Mean Square Error) 알고리즘을 적용하였고, 파일럿 배치 및 패턴에 따른 영향성을 분석하였다. 모의 실험결과 파일럿 배치 및 패턴에 따라 성능 차이를 확인할 수 있었고, 본 논문에서 제시한 프레임 구조를 통해 실제 운용 환경에서도 고속의 무인기에 대해 안정적인 보조링크를 제공할 수 있음을 확인하였다.

• 대한인간공학회지
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• 제33권6호
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• pp.499-513
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• 2014

Objective: The objective of this study was to examine frame ratio of text information and font size in the circle smartwatch. Background: Recently, electronic manufacturers try to develop the original metaphor of traditional wrist watch (circle) in terms of smartwatch. They endeavor to break the square display in order to improve emotional customer satisfaction. Method: The experiments examined twenty level of text information design, combinations of four frame ratios (1:1, 4:3, 16:9, 21:9) and five font sizes (6pt, 7pt, 8pt, 9pt, 10pt). Nineteen participants volunteered for the experiment. Dependent variables were WPM (Words per Minute), reading preference, design preference and total preference. Furthermore, small circle display was made by using circle display data (1.3inch), which was exhibited in IFA (International Funkausstellung) 2014. Results: As a result, ANOVA (Analysis of Variance) revealed that WPM, and task time preference affect the specific frame ratio and font size. Results of ANOVA for reading preference, design preference, total preference were grouped by post-analysis LSD (Least Significant Difference). Among users, display ratio (16:9, 21:9), and font size (9pt) were preferred. In conclusion, 16:9 display ratio and 9pt are adaptable for text information in 1.3inch circle display. Conclusion: From the study, it is shown that 16:9 display ratio and 9pt size are more adaptable for text information in 1.3inch circle display than others. It is mainly due to the fact that the order of frame ratio and font size may affect the usability of reading long text information in a small circle display. Therefore, when developers design a circle display, the square frame ratio and font size are required to be considered according to circle size. Application: The 16:9 display ratio and 9pt font size may be utilized as a text information frame in the circle display design guideline for smartwatch.

• 감성과학
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• 제24권4호
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• pp.29-38
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• 2021

한글 글꼴의 눈에 띄는 특성에는 세리프 및 네모틀 여부가 있다. 꺾임 또는 삐침으로 장식된 글꼴은 세리프(serif)로 분류되며, 이러한 장식이 없는 글꼴은 산세리프(san-serif)로 분류된다. 반면 네모틀은 알파벳 글꼴에는 없는 특징 범주이며, 가상의 사각형 안에 자, 모음, 그리고 받침이 조화를 이루는 특징을 의미한다. 본 연구는 오랫동안 광범위하게 사용되어 온 세리프와 네모틀 글꼴 특성을 보유한 글꼴이 그렇지 않은 글꼴보다 친숙성과 선호도가 높을 것을 가정했다. 이 가설을 검증하기 위해 한글 팬그램을 사용한 네모틀 및 탈네모틀 글꼴 그리고 세리프 및 산세리프 글꼴을 제시해 해당 네모틀 및 세리프 유무에 따른 친숙성과 선호도를 조사했다. 그 결과 참가자들은 탈네모틀 글꼴에 비해 네모틀 글꼴에 대해 친숙성과 선호도를 모두 높게 평가했으나 세리프와 산세리프 사이에 이러한 차이는 발견되지 않았다. 더 나아가 친숙성과 선호도 사이의 정적 상관은 탈네모틀 세리프 글꼴에 대해서만 관찰되었다. 이 결과는 네모틀의 특징을 보유한 한글 글꼴이 그렇지 않은 글꼴에 비해 더 친숙하고 선호될 가능성을 의미한다. 특히 본 연구는 한글 글꼴 사용자들에 있어서 익숙하고 편안한 글꼴로 네모틀 글꼴이 권장되며, 더 나아가 세리프를 동반한 네모틀 글꼴이 사용될 경우 이러한 긍정적 감성이 향상될 가능성을 시사한다.

• 조명전기설비학회논문지
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• 제28권11호
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• pp.68-76
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• 2014

This paper presents an offset error compensation algorithm for the accurate phase angle of the grid voltage in single-phase grid-connected inverters. The offset error generated from the grid voltage measurement process cause the fundamental harmonic component with grid frequency in the synchronous reference frame phase lock loop (PLL). As a result, the grid angle is distorted and the power quality in power systems is degraded. In addition, the dq-axis currents in the synchronous reference frame and phase current have the dc component, first and second order ripples compared with the grid frequency under the distorted grid angle. In this paper, the effects of the offset and scaling errors are analyzed based on the synchronous reference frame PLL. Particularly, the offset error can be estimated from the integrator output of the synchronous reference frame PLL and compensated by using proportional-integral controller. Moreover, the RMS (Root Mean Square) function is proposed to detect the offset error component. The effectiveness of the proposed algorithm is verified through simulation and experiment results.