• 제목/요약/키워드: Front to back ratio

검색결과 138건 처리시간 0.024초

(-) 구면 렌즈 면의 반사상에 의한 굴절력 측정 (Measurement of Refractive Power by Reflective image on the Negative Spherical Lens)

  • 최운상;김대현
    • 한국안광학회지
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    • 제9권2호
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    • pp.417-421
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    • 2004
  • 안경렌즈 면 위에 반사되는 상을 관찰하연 한 물체에 대해 두 개의 상이 나타나 있다. 이것은 렌즈 전면에서 반사되는 상과 렌즈 후면에서 반사되는 상이다. 이 상들은 렌즈 전, 후면의 굴절력에 의해 렌즈 면에서 반사되는 상이며, 렌즈 전체의 굴절력은 렌즈 전, 후면의 굴절력을 이용하면 얻을 수가 있다. 그러므로 렌즈 면 위에서 나타나는 상 크기 측정은 렌즈의 굴절력을 측정하는 기기의 도움 없이 렌즈의 굴절력을 측정하는 방법이 될 수 있다. 렌즈 면 위에서 측정된 두 개 반사상의 비와 굴절력을 측정하여 계산한 값과 비교하였다.

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위성 DMB 중계기용 Cavity-Backed슬롯 배열 안테나 (Cavity-Backed Slot Array Antenna for a Repeater System of a Satellite Digital Multimedia Broadcasting)

  • 정희철;이학용;정병운;강기조;박면주;이병제
    • 한국전자파학회논문지
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    • 제16권4호
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    • pp.366-372
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    • 2005
  • 본 논문에서는 $2,630\;\cal{MHz}\~2,655\;\cal{MHz\$의 위성 DMB(Digital Multimedia Broadcasting)의 지상 중계기 시스템에 적합한 낮은 부엽레벨과 높은 전후방 비를 갖는 슬롯배열 안테나를 제안하였다. 중계기용 안테나는 시스템의 특성상 고이득과 시스템간의 신호 간섭을 줄이기 위해 충분한 격리도가 확보되어야 하며, 이를 위해서는 안테나의 부엽레벨을 억제시키고, 전후방 비는 증대시켜야 한다. 제안된 안테나는 도파관 구조의 직접급전이 가능한 CBSA(Cavity-Backed Slot Array) 안테나이다. 일반적인 마이크로 스트립 급전라인을 이용한 구조와는 달리 유전체 손실이나 급전라인의 손실이 없는 공기를 매질로 하므로, 고출력에 적합하며, 고효율을 가진다. 또한 tapered 배열 방식과 최적화된 수직 반사판을 이용하여 부엽레벨 및 전후방 비를 개선하고 이득을 증대시켰다. 제작 및 측정을 통하여 부엽레벨은 수평 및 수직면에서 각각 $-33.24\;\cal{dB}$ 이하, $-35.78\;\cal{dB}$ 이하를 얻었고 전후방비는 $37.84\;\cal{dB}$ 이상, 이득은 전 대역에서 $17\;\cal{dBi}$ 이상을 얻었다.

부인복 길원형 제도법에 관한 비교연구 (A Comparative Research on the Drafting Method of the Basic Basuc Bodice Patterns for Women)

  • 구미지
    • 대한가정학회지
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    • 제32권2호
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    • pp.219-230
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    • 1994
  • The purpose of this comparative research is to investigate the change of the drafting method of the basic patterns for women in Korea. Followings were the findings of this research: 1) The concept of the basic pattern could be found after the first of the 1950s and there was introduction of the many basic patterns. At first measurement couldn't be found. Gradually the personal body type could be expressed in the basic pattern through the practical measurements such as the width of highest bust level and the length of neck to bust. 2) Through the ages the changes of the basic patterns were between 1950,60s and 1980,90s distinctively at the back width back shoulder angle front and back shoulder height from biceps line back neck ratio(height/width) BP position at the biceps line the amounts of underarm dart underarm dart position from the biceps lines and front ease angle at BP line. 3) 4 Grouping the types of the basic pattern followings are their characters; 1st Munwha or Doreme style 2nd waist dart group 3rd underarm dart and rectangular front ease 4th the usage of many measurements like as front length upper bust girth etc.

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흡음형 방음벽의 성능향상에 관한 연구 (A Study on Performance Improvement of Sound Absorbing Noise Barrier)

  • 김현실;김재승;강현주;김봉기;김상렬
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 추계학술대회논문집 II
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    • pp.849-854
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    • 2001
  • A study on performance of the sound absorbing noise barrier is presented. Noise barrier of sound absorbing type is composed of the front panel, sound absorbing material, and back panel. For allowing sound path, front panel is usually perforated. The performance of the noise barrier is governed by the opening ratio of the perforated panel, sound absorption coefficient of the sound absorbing material. In this study, the effects of the opening ratio, diameter of the hole, thickness of the sound absorbing material are investigated. It is found that the thickness of the sound absorbing material must be at least 50 mm to ensure the required minimum NRC value 0.70, and the opening ratio is greater than 0.2. It is shown that the thickness of the back panel is crucial in providing required STL (Sound Transmission Loss) value. The performance of the developed noise barrier is measured, where its sound absorbing coefficient and sound transmission loss satisfy the criteria.

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머리전달함수의 심리음향적 특성을 이용한 전/후 음상정위 특성 개선 (Improvement of front/back Sound Localization Characteristics using Psychoacoustics of Head Related Transfer Function)

  • 구교식;차형태
    • 방송공학회논문지
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    • 제11권4호
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    • pp.448-457
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    • 2006
  • 일반적으로 3D 입체음향을 생성하기 위해서는 소리가 음원으로부터 청자의 두 귀에 이르는 정보를 포함하고 있는 머리전달함수를 사용한다. 그러나 HRTF의 비개인화적인 특성 때문에 양쪽 귀까지의 거리가 같아지는 혼돈원추상에서는 앞/뒤 방향지각에 대한 혼돈을 주게 됨으로써 입체감을 저하시키게 된다. 이에 본 논문에서는 인간의 청각특성에 따른 여기에너지를 이용하여 앞/뒤 음상정위의 특성을 개선하는 방법을 제안하고자 한다. 서로 대칭되는 각 HRTF의 여기 에너지를 계산하고 각 bark 대역에 따른 에너지의 비율을 추출하는 방식으로써 각 HRTF의 스펙트럼 특성을 부각시키는 방법을 제안하였으며 청감테스트를 통해서 제안한 방식이 기존 방법보다 방향감을 개선시킴을 확인할 수 있었다.

$\gamma$선(線)(Ir-192)이 연박(鉛箔)두께의 증감(增減)에 따른 필름감도(感度) 효과(效果) (A Study on Film Sensitive Effect Influenced by ${\gamma}-ray$(Ir-192) Depending on Thickness of Lead Foil)

  • 주광태
    • 대한방사선기술학회지:방사선기술과학
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    • 제2권1호
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    • pp.95-99
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    • 1979
  • When the ${\gamma}-ray$ of average energy 375KeV emitted by Ir-192 is exposed to each film through lead foil with various thickness, the film sensitivity will be different according to the thickness of lead foil and film type. The results on the study, different density and sensitive ratio appeared depending on exposed time and film type, but was made on the following common points. 1. The effect of film sensitivity by the front lead foil showed rapid increase up to the thickness of more or less 0.03mm, and the thicker lead foil was decreased more in the thickness of about $0.05{\sim}0.09mm$. 2. The effect of film sensitivity by the back lead foil was increased up to around of $0.03{\sim}0.08mm$ thickness, the maximum sensitivity was obtained in the thickness of more than $0.03{\sim}0.08mm$ without any change in the above effect. 3. The sensitivity of front lead foil was higher than that of back lead foil in thin lead foil with about 0.127mm thickness, but the sensitivity of back lead foil was higher than that of front lead foil when thickness became thicker.

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재단각도 변화에 따른 오그림에 관한 연구 (제 2보) -소매산높이에 따른 각도변화를 중심으로- (A Study on Easing contraction made by different angles(Part II) -About variations of sleeve cap curve lines-)

  • 이명희
    • 한국의류학회지
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    • 제23권3호
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    • pp.353-360
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    • 1999
  • An investigation made of the variations of angle of bias on the top of the sleeve cap curve line and calculated easing contraction ratio by capheights(A ; a,h$\times$5,/6) B: A, H/4 +4cm C:A.H/3 D: A.H/ 4+3cm E:AH/4+2cm, F: A,H/4+1cm, G: A,H/4, H:A,H/6, I:A,H/8) and the efects of easing contraction on the cap curve lines of sleeve A, D, G by easing stitch density with the gathering foot: sewing condition-lockstitch industrial machine stitch density(N1.0 ; 38stitches/3cm N1.5: 26stitches/3cm, N2.0 ; 19stitches/3cm, N2.5 ; 14stitches/ 3cm) The results obtained were as follows; 1) The variations of the angle of bias on the top of the sleeve cap curve line by cap heights can be done according to the angle balance (front; $\alpha$-$\beta$ back ; $\alpha$'- $\beta$') between the angle (front ;$\alpha$, $\beta$, back ; $\alpha$'- $\beta$') of bias of the two base-lines. 2) The higher cap height the more higher the calculated easing contraction ratio. 3) The lower the stitch density the higher easing contraction ratio. 4) The effects of easing contraction was that sleeve G was more than sleeve A, D.

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가상착의 시뮬레이션을 이용한 소매 오그림량 배분에 따른 외관평가 (The Evaluation of Sleeve Appearance on Sleeve Easing Contraction Using Virtual Garment Simulation)

  • 오영순;김여숙
    • 한국지역사회생활과학회지
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    • 제24권4호
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    • pp.457-469
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    • 2013
  • The purpose of this study is to quantitatively analyze the impacts of the distribution of easing contraction of the sleeve on the external appearance of bodice and sleeve through virtual clothing simulation. Virtual clothing is conducted by differentiating the sleeve easing in accordance with the experimental condition of bodice and sleeve that are followed by draping. And then the evaluation is carried out. As a result of an analysis of the similarity between the virtual garment and the actual clothing, the whole external appearance of the bodice and sleeve was expressed similarly. The external appearance according to the distribution of easing contraction got better as the easing contraction of sleeve was concentrated on sleeve cap in front while the appearance was better at the back as it was more gently distributed than in the front. In a comparison of armhole form, the clothing of which the top of it was most similar to S0 was S4 in which the gap between the armhole and the arm was the least and the front and rear silhouette fell relatively well. In a comparison between the position of bust circumference line and that of the sleeve base line, the front of the sleeve matched the bust circumference line as the easing contraction was distributed close to the center of the sleeve cap while in the back, the sleeve base line and the bust circumference line matched when some easing contraction ratio was added close to the armpit point. The cross section figures of garment space of the shoulder, the margin was evenly distributed in S4 or S5 with differing distributions of easing contraction in the front and the back. This study is significant in that it supplies the objective baseline data which makes a novice more able to make a good external appearance of the sleeve.

현실적인 3D 입체음향 구현을 위한 HRTF의 앞/뒤 음상정위 특성 개선 (Improvement of sound localization for real 3D Sound)

  • 구교식;한상일;서보국;차형태
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2007년도 하계종합학술대회 논문집
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    • pp.415-416
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    • 2007
  • HRTF DB, including the information of the sounds which is arrived to our ears, is generally used to make a 3D sound. But it can decline some three-dimensional effects by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that reduces the confusion of sound image localization. And we make use of an excitation energy by the sense of hearing. This method is brought HRTF spectrum characteristics into relief to draw out the energy ratio about the bark band and control low frequency band. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than the conventional methods.

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팔 동작에 따른 소매유무별 블라우스의 착의 공극량 변화 (A Change of the Gap in Dressed Blouses with Above-elbow Sleeves and Sleeveless According to Arm Movements)

  • 이명희
    • 한국의류학회지
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    • 제34권11호
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    • pp.1779-1785
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    • 2010
  • The experiment is designed to create some useful data on the dressed shapes that contribute to simulating the adaptability of clothes. We studied the dressed shapes of blouse with above-elbow sleeves and sleeveless according to five types of arm movement (basic posture, reach forward 45, 90, and reach lateral 45, 90) in the stand-posture. Experiments were conducted to understand the dressed shape through 3-D measurement Vivid 910 and to investigate the width, depth, area distribution and gap of the shape of blouses on the section map with a software program for 3-D shape analysis, Rapid Form 2004. The Data were analyzed by factor analysis. The results of this study are as follows: The ratio of depth per width in the stand-posture was lower than other arm movements and the reach lateral was higher than the reach forward. The gap of the upper body was a briefed 4 factor; front, front-side, back, and back-side. It was higher than the sleeveless with a change of the gap in the dressed blouse with above-elbow sleeves by arm movements per stand-posture. The divisional gap shows the adaptability of clothes according to the types of blouse and arm movements in the change of the ratio.