• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1033-1036
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to equip 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added tilting mechanism to 2-axis moving magnet actuator which is designed in previous research. Addition of the tilting mechanism cuts down the focusing sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.

• Journal of Astronomy and Space Sciences
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• 제31권3호
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• pp.241-246
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• 2014

The Amon-Ra instrument is the main optical payload of the proposed EARTHSHINE satellite. It consists of a visible wavelength instrument and an IR energy channel instrument to measure a global Earth albedo. We report a new sensitivity technique for efficient alignment of the visible channel instrument. Whilst the sensitivity table method has been widely used in the alignment process, the straightforward application of the method tends to produce slow process convergence because of shop floor alignment practice uncertainties. We investigated the error sources commonly associated with alignment practices and used them when estimating the Zernike polynomial coefficients. Aided with single center field wavefront error (WFE) measurements and their corresponding Zernike polynomial coefficients, the method involves the construction and use of an experimental, instead of simulated, sensitivity table to be used for alignment state estimations. A trial alignment experiment for the Amon Ra optical system was performed and the results show that 71.28 nm in rms WFE was achieved only after two alignment iterations. This tends to demonstrate its superior performance to the conventional method.

• 정보저장시스템학회논문집
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• 제3권4호
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• pp.191-195
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to be equipped with 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added a tilt mechanism to the 2-axis moving magnet actuator which is designed in previous research. Addition of the tilt mechanism cuts down the focus sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.

• Structural Engineering and Mechanics
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• 제74권6호
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• pp.771-787
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• 2020

The paper provides an inside look into experimental measurements, followed by numerical simulations and their related uncertainties. The goal of the paper is to present findings related to blast loading and the handling of defects that are inherent in experiments. Very often it might seem that experiments are simplified reflections of real-life conditions. In most cases this is true, but there is a good reason for that. The more complex an experiment is, the larger the amount of uncertainties that can be expected. This especially applies when the blast loading of concrete is the subject of research. When simulations fail to reproduce the results of experimental measurements, it does not necessarily mean there is something wrong with the numerical model. The problem could be missing information. Put differently, the numerical simulation may lack information that seemed irrelevant with regard to the experiment. In the presented case, a reference simulation with a proven material model unexpectedly failed to replicate the results of an experiment where concrete slabs were exposed to blast loading. This resulted in a search for possible unknowns. When all of the uncertainties were examined, the missing information turned out to be the orientation of the charge to the concrete slab. Since the experiment was burdened with error, a sensitivity study had to take place so the influence of this factor could be better understood. The findings point to the fact that even the smallest defect during experiments must somehow be taken into account when designing numerical simulations. Otherwise, the simulations are not correlated to the experiments, but merely to some expectations.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.120-128
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• 2000

At the initial design stage of a new vehicle, the chassis layout has the most important influence on the overall vehicle performance. Most chassis designers have achieved the target performances by trial and error method as well as individual knowhow. Accordingly, a general procedure for determining the optimum location of suspension hard points with respect to the kinematic characteristics needs to be developed. In this paper, a method to optimize the toe angle in the double wishbone type front suspension of the four-wheel-drive vehicle is presented using the design of experiment, multibody dynamic simulation, and optimum design program. The handling performances of two full vehicle models having the initial and optimized toe angle are compared through the single lane change simulation. The sensitive design variables with respect to the kinematic characteristics are selected through the experimental design sensitivity analysis using the perturbation method. An object function is defined in terms of the toe angle among those kinematic characteristics. By the design of experiment and regression analysis, the regression model function of toe angle is obtained. The design variables which make the toe angle optimized ae extracted using the optimum design program DOT. The single lane change simulation and test of the full vehicle model are carried out to survey the handling performances of vehicle with toe angle optimized. The results of the single lane change simulation show that the optimized vehicle has the more improved understeer tendency than the initial vehicle.

• 대한건축학회논문집:계획계
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• 제34권9호
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• pp.55-66
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• 2018

This study aims to propose color affective model of indoor space by evaluating subjects' physiological responses according to the types of behavioral and affective system. 99 subjects(44 females, 55 males) in their 20s, who had no disorders in visual perception, participated in the experiment. To categorize the subjects based on behavioral and affective system, BAS/BIS scale and Affective scale were used. Color stimuli were composed of five basic colors and three tones: vivid, pale and dull tone of R, Y, G, B, P. For physiological experiment, right and left prefrontal alpha activity was measured to analyze prefrontal EEG asymmetry. Participants were exposed to fifteen color stimuli for 20 seconds each other under the positive and negative emotional condition in a research room with the natural light blocked. The results and conclusion of this study are as follows. Along with factors of behavioral and affective system, cluster analysis was carried out and four types were classified. Type A had high BAS sensitivity, especially high 'drive' trait, and showed high levels of 'anxiety' and 'anger'. Type B had low BAS sensitivity, especially low 'fun seeking' and low 'drive' trait, and showed low levels of 'anxiety' as well as low levels of 'happiness'. Type C had low BIS sensitivity and showed high levels of 'happiness' and low levels of 'sadness'. Type D had high BIS sensitivity and showed high levels of 'lethargy' and 'sadness'. As a result of EEG signal analysis of color stimuli, Type B, Type C, and Type D showed significant differences in prefrontal alpha asymmetry under the negative emotional stimuli. Type B showed more left prefrontal activation in the spaces with pale R and dull G. Type C showed more left prefrontal activation in the spaces with vivid Y and B, pale R, and dull R, G, P. Type D showed more left prefrontal activation in the spaces with vivid Y and P, pale R, Y, P, and dull R, Y, G, B, P. The group of high BAS sensitivity was not influenced by color stimuli under the emotional conditions, whereas the group of high BIS sensitivity was affected by color stimuli under the negative emotional conditions. They showed left prefrontal activation when they were exposed the spaces with vivid, pale, dull tones of Y and P wall.

• 방재기술
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• 통권18호
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• pp.5-16
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• 1995

The capacity commonly required sensors includes capability of quickly and properly catching the conditions of a fire and discriminating other factors such as noise, interference, etc. IR flame detector which react to the infra-red rays emitted from the flame. This study is aimed to know the characteristic repond to the specified fire plate. Experiment is acted by manufacture's technical data that is explained relation of detective range and sensitivity.

• 한국실내디자인학회논문집
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• 제23권6호
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• pp.42-50
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• 2014

The purpose of this study is to analyze the change of perception and to measure the degree of interaction between the lighting and the finishing materials according to preference types and the impacted factors to the spatial sensitivity of users. To do that, the this change was grasped through the experiment with Likert Scale and ANOVA of SPSS program to the simulated images. The result of this study is as following. Firstly, the personal difference in the perception of space comes from 'attention' in information processing process. The degree of the perception of users change strongly by lighting in the space expressed the 'modern natural'. Secondly, the atmosphere and the degree of perception are different in the preference of users to the spatial sensitivity and in impacted factors which are thought by users in the space sensitives. The users who prefer the 'decoration' feel the mood more strongly in the space. But the users who prefer the 'active' and 'intimacy' are opposite to that. The difference to the degree of perception is greater in the 'classic natural' than the others under the lighting turns on. Thirdly, an in-depth research which is considered of the interaction among the various factors is needed for finding the design methods for inducing the sensitivity of users in the space. And the ranking of the impacted factors should be understanded and applied to the research regarding the changes of perception in the space. Finally, this study has the limitation to be adapted to all of the situation for the space design methods. But this will be a basic data to study the design methods for users's sensitivity in the space.

• 한국항행학회논문지
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• 제23권5호
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• pp.415-423
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• 2019

본 논문에서는 유전율 측정을 위한 구부러진 슬롯이 추가된 고감도 마이크로스트립 패치 센서 안테나의 설계 방법에 대하여 연구하였다. 유전율에 대한 감도를 향상시키기 위해 단일 링 CSRR 구조와 유사한 구부러진 슬롯이 패치의 한쪽 방사면에 추가되었다. 제안된 마이크로스트립 패치 센서 안테나의 감도를 기존의 직사각형 마이크로스트립 패치 센서 안테나와 얇은 직사각형 슬롯이 추가된 마이크로스트립 패치 센서 안테나와 비교하였다. 세 마이크로스트립 패치 센서 안테나는 피 시험 상판이 없는 상태에서 전송 계수가 2.5 GHz에서 공진하도록 0.76 mm 두께의 RF-35 기판 상에 설계하고 제작하였다. 피 시험 상판으로 비유전율이 2.17에서 10.2 범위에 있는 타코닉 기판 5종을 사용하여 실험한 결과, 입력 반사계수의 공진 주파수의 이동으로 측정된 제안된 마이크로스트립 센서 안테나의 감도는 기존의 직사각형 마이크로스트립 패치 센서 안테나와 비교할 때 4.1배에서 6.1배 증가하는 것을 확인하였다.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.142-147
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• 2014

Finite element analysis along with DOE scheme has been performed to obtain robust design of connecting rod assembly. An analysis was conducted with five loading steps. Fatigue analysis was done using commercial software FEMFAT and fatigue safety factors at the interested regions such as shank area of small end and big end were calculated. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Each case is simulated to find the most influential factors. Response for this study, maximum Von-Mises stress, has been used to determine main factors of connecting rod assembly. Among the 3 factors, compression load affected the response greatly. However, bolt assembly load and width of shank flat area showed a little influence to the response. Interaction effects among factors considered did not occur. Connecting rod assembly considered in this study showed its sensitivity to the noise factor such as compression load rather than design factor such as width of flat shank area.