• Title/Summary/Keyword: 근시화

Search Result 20, Processing Time 0.029 seconds

Structural Behavior Characteristics and Efficiency Evaluation of Outrigger System using Stiffness-Based Optimal Design Technique (강성최적설계법을 이용한 아웃리거 시스템의 거동특성 및 효율성 평가)

  • Kim, Ho-Soo;Lee, Han-Joo
    • Journal of Korean Association for Spatial Structures
    • /
    • v.5 no.3 s.17
    • /
    • pp.123-130
    • /
    • 2005
  • This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift and evaluate the structural behavior characteristics and efficiency for tall outrigger system subject to lateral loads. To this end, displacement sensitivity depending on behavior characteristics of outrigger system is established and approximation concept that preserves the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Specifically, under the 'constant-shape' assumption, resizing technique of member is developed. Four types of 50 story frameworks are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

  • PDF

A Study of Myopia Progression Status for a Elementary School Student Group in Daegu Dalseogu Region (대구 달서구 지역 초등학생들의 근시진행 정도에 대한 연구)

  • Lee, Byung-Hwa
    • Journal of Korean Clinical Health Science
    • /
    • v.1 no.3
    • /
    • pp.33-37
    • /
    • 2013
  • Purpose. In this study, we divided elementary school students into two investigated groups. The A group is the lower graders(boys 9, girls 18), and the B group is the higher graders(boys 10, girls 13). The myopia progression has been compared with to each group and it has been investigated for variable terms. Methods. We have analyzed the refraction inspection record of 50 students(boys 19, girls 31) who visited optical shops and more than two times in one year. Results. The subject of study were 50 students(boys 19, girls 31). 1. The distribution of spherical equivalent power with ages : boys A group -2.42D, girls A group -2.53D, boys B group -2.63D, girls B group -2.78D. boys B group -2.63D, girls B group -2.78D. 2. The monthly variation of spherical equivalent power : -0.055D(A), -0.04D(B) in boys, and -0.065D(A), -0.07D(B) in girls. Conclusions. Considering monthly variations and Supposing that the time of changing spectacles degrees were the time of refracting inspection. The result : 3.8 month for A group, 4.5 month for B group in boys, and 3.5 month for A group, 5.2 month for B group in girls.

  • PDF

Design and Implementation of the Quantity Surveying and Shop Drawing System for Structures (BIM 기반 골조 물량산출 및 도면생성 모듈의 설계와 구현)

  • Lee, Byung-Kwon;Kim, Chee-Kyeong
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2011.04a
    • /
    • pp.132-135
    • /
    • 2011
  • 최근 설계 단계에서 설계품질 향상과 시공 단계에서 비용 절감을 효과를 기대하며 3차원 BIM 관련 기술에 대한 관심이 높아가고 있으며, 또한 부분적으로 기술 도입 효과가 나타나고 있다. BIM 기술은 크게 BIM 도구를 활용하여 설계정보를 디지털화하는 모델링 단계 기술과 BIM 모델로부터 설계 정보를 추출하여 업무 진행에 필요한 형태로 가공, 변환하는 정보 활용 기술로 구분하여 생각할 수 있다. BIM 기술에 대한 근자의 높은 관심에도 불구하고 실제 현장에 적용되어 가시적인 성과를 내는 데에 한계를 보이고 있는 이유 중 하나로 후자의 정보 추출 및 활용 기술의 범위와 완성도의 한계를 들 수 있다. 즉 많은 노력을 통하여 BIM 모델을 구축하더라도 이를 기반으로 물량산출, 도면 생성 등 가장 기본적인 업무조차도 현장에서 바로 사용할 수 있는 수준의 기능이 제공되고 있지 않다. 본 연구에서는 건축 골조를 대상으로 3차원 골조 모델을 이용하여 골조 물량, 특히 정확한 물량산출이 상대적으로 어려운 철근에 대하여 철근의 이음, 정착 등이 고려된 실행물량을 산출할 수 있는 시스템을 설계하고 구현하였다. 또한 3차원 모델을 기반으로 철근 배근시공도와 가공일람표를 관련 기준에 따라 정확히 자동 작성함으로써 골조공사가 효율적으로 수행되고, 특히 정확한 이음 및 정착과 가공 계획을 통하여 철근 손실율을 최소화함이 기대된다. 본 논문에서는 이러한 BIM 기반 골조 물량산출 및 도면생성 시스템과 관련하여 주요 시스템 설계 내용과 구현 결과에 대하여 기술한다.

  • PDF

The Investigation of the Changes of Visual Problems in VDT Workers (VDT 작업 전·후 시기능 변화)

  • Gang, Myoung Jin;Choe, Oh Mok
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.7 no.2
    • /
    • pp.33-39
    • /
    • 2002
  • The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal). Therefore, we examined visual fatigue by a questionnaire and measured frequency of blinking, tear film break-up time(BUT), height of palpebral fissure, visual acuity, refraction with retinoscopy and accommodation before and after two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 34%. In the visual symptoms, blurred vision was the highest rate of 83% and in case of systemic symptoms, shoulder pain was 38% marked top ranking but other symptoms were also distributed similar rate. The frequency of blinking during VDT work decreased significantly comparing with the one at rest. The average frequency of blinking is 8/min during VDT work and 22/min at rest. The BUT measured immediately after VDT work decreased much more than in the resting state. The average BUT was 7sec immediately after VDT work and 12sec at rest. The height of palpebral fissure during VDT work increased significantly comparing with the value at rest. The average height of palpebral fissure was 7.69mm at rest and 9.04mm during VDT work. The average visual acuity decreased almost 9.5% from 0.63 to 0.57, but refraction with retinoscopy increased about 0.28D to the direction of myopic shift. The amplitude of accommodation decreased approximately 1.49D from 7.98D to 6.49D and this resulted from the prolongation of near point of accommodation. Near point of convergence also was prolongated from 9.45cm to 10.30cm after VDT work.

  • PDF

"온병조변"(溫病條辨)의 온병학설(溫病學說)에 관(關)한 연구(硏究) -關于(관우) "온병조변"(溫病條辨)적온병학설연구(的溫病學說硏究)-

  • Park, Hyeon-Guk;Kim, Gi-Uk
    • Journal of Korean Medical classics
    • /
    • v.18 no.1 s.28
    • /
    • pp.7-32
    • /
    • 2005
  • 청대적명의오국통(淸代的名醫吳摘通), 불근시'온병'제가(不僅是'溫病'諸家), 우시관어림상각과논치적명가(又是關於臨床各科論治的名家). 관어(關於)${\ulcorner}$온병조변${\lrcorner}$(溫病條辨)상온병학(上溫病學)술리논적특정(術理論的特征), 정리여하(整理如下). 대온병병인(對溫病病因), 파융합제가문학설(把融合諸家們學說), 규명시종일관(糾明始終一貫), 제시료정상화비정상적'복기'(提示了正常和非正常的'伏氣'), '사천시영현행지기'('司天時令現行之氣'), '려기'인기온병적삼도인치온'지학설('戾氣'引起溫病的三圖因致溫'之學說). 吸收諸家們的長處(흡수제가문적장처), 創案'三焦辨證'濃體系(창안'삼초변증'농체계). 수선(首先), 타이'삼초'위강영구분병위적상하(他以'三焦'爲綱領區分病位的上下), 천채(淺採), 기차이'륙경'위구별설명장역부화경락적불동(其次以'六經'爲區別說明?驛腑和經絡的不同), 재일차이'위기영혈'(在一次以'衛氣營血') 구별료표리적선후(區別了表裏的先後). 우용횡향급종향논술료온사적전변규률(又用橫向及縱向論述了溫邪的傳變規律), 최후제시료'치상초여우(最後提示了'治上焦如羽), 비경불거(非輕不擧). 치중초여형(治中焦如衡), 비평불안(非平不安). 치하초여권(治下焦如權), 비중불침(非重不沈).'적약물치료원칙(的藥物治療原則). 재질병적변별구분'온열'화'습열'(在疾病的辨別區分'溫熱'和'濕熱'), 재약물적사용상구별'강조'화'유윤'(在藥物的使用上區別'剛燥'和'柔潤'), 저우시오씨적온병학술특징지일(這又是吳氏的溫病學術特徵之一). 재치법(在治法), 방제(方劑), 약양(藥量), 전법(煎法), 복법(服法), 음식(飮食), 조양등적온병치료방면(調養等的溫病治療方面), 제시료광범위적'금기'학설(提示了廣範圍的'禁忌'學說). 타심각적감각도료오치온병적결과(他深刻的感覺到了誤治溫病的結果), 위료방지오치(爲了防止誤治), 관전치료'금기'(灌展治療'禁忌'), 현재야필요준수적충분적가치(現在也必要遵守的充分的價値).

  • PDF

Survey on the eye health state of institutional care children in Taejon (대전지역 시설아동의 안보건 실태 조사)

  • Hwang, Jeong Hee;Park, Joon Chul
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.5 no.2
    • /
    • pp.73-78
    • /
    • 2000
  • The purpose of our study was investigation for the status of eye health in Taejon area. I chose the age of eight to under eighteen 61 institutional care children, and I examed the first visual acuity examination ophthalmoscopy and non-criterion interview. Among 61 institutional care children (primary school student 40.98%, secondary school student 59.01%), 56.74% children were emmetropia, 44.46% were ametropia. Unaided visual acuity 0.7, 0.8 were 37.03% of these children. As refractive errors, 31.14% were myopia. 26.23% were compound myopic astigmatism and only 1.64% institutional care children wearing the glasses. In children, early eye examination is essential for their eye health. Therefore attention to early eye examination and wearing correct glasses seem to be very important especially for institutional care children. I propose that we have to concerned about eye health and concrete plan for institutional care children.

  • PDF

A Study on the Certification System for eVTOL Aircraft (전기추진 수직이착륙 항공기 인증제도에 대한 고찰)

  • Lim, Daejin;Yee, Kwanjung
    • Journal of Aerospace System Engineering
    • /
    • v.15 no.3
    • /
    • pp.20-29
    • /
    • 2021
  • As the feasibility of urban air mobility (UAM) service using electric vertical take-off and landing (eVTOL) aircraft increases due to aircraft electrification, distributed propulsion, and artificial intelligence technologies, the U.S. and European aeronautical societies have been improving their certification system and regulations for the type certification of eVTOL. The improved certification system is expected to be ready in the near future, after the European Union Aviation Safety Agency (EASA) proposed the VTOL Special Condition, SC-VTOL in 2019. However, the current domestic certification system is still insufficient to properly respond to eVTOL. This study investigated the development trends of foreign eVTOL and certification systems, identified considerations to improve the domestic certification system, and proposed the measures for type certificates and type certificates validation of eVTOL based on the comparison between SC-VTOL and Korea airworthiness standards (KAS).

Desing of VR Contents for Visual Function Enhancement (VR 기반 시기능 강화 콘텐츠 설계 및 제작)

  • Yong-Ju Kim;Sang-Joong Jung
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.23 no.2
    • /
    • pp.70-75
    • /
    • 2022
  • With the spread of various digital devices, devices have become commonplace in modern society. Moreover, due to the increase in device usage and online learning while staying indoors during the COVID-19 pandemic, symptoms such as an increase in myopia in children due to eye fatigue, an increase in young presbyopia, and dry eye syndrome are increasing, and now people are paying attention to eye health. This is different from before. There are various prescriptions for eye health, but in this paper, we would like to propose a training method for enhancing visual function using VR contents. The analog methods of the existing teaching aids for visual function reinforcement training were planned and produced as digital contents, and VR-based training contents were selected from among the various methods carried out with teaching aids at the visual function training center, which can be made into contents. was developed with In the training process for each content, it was proposed to apply eye tracking to the VR device in order to give the user feedback on their participation in the training so that the management and concentration of the training process could be analyzed.

Comparison of Photosynthetic Rates among Panax Species and Cultivars (인삼의 종 및 품종간 광합성 특성비교)

  • 이성식;천선용;이종화
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.32 no.2
    • /
    • pp.157-162
    • /
    • 1987
  • The study was carried out to investigate the effects of light intensity, temperature and seasonal trends on the photosynthesis as well as the physiological characteristics of Panax species and cultivars. Four-year-old plant of Violet-stem variant, Yellow-berry variant, Mimaki and Russian ginseng of Panax ginseng C. A. Meyer and American ginseng of Panax quiquefolium L. were used for study. These Panax species and cultivars were cultivated under the straw shading. The light saturation point of leaves in Violet-stem variant, Yellow-berry variant, Mimaki and American ginseng were 15,000 lux, but that of Russian ginseng was 10,000 lux. The optimum air temperature on the phtosynthesis of Violet-stem variant, Yellow-berry variant, Mimaki and American ginseng were 20$^{\circ}C$ but that of Russian ginseng was 15$^{\circ}C$ under 15,000 lux. The photosynthetic rates were increased in order of Russian ginseng, Mimaki, Yellow-berry variant, Violet-stem variant and American ginseng. The respiration rates of ginseng leaves were increased according to the increasing of temperature, but it was not different among Panax species and cultivars. Stomata frequency of American ginseng was highest, that of Russian ginseng lowest, while the length of stomata was reverse. The total chlorophyll content of American ginseng and specific leaf weight of Mimaki were higher than other ginseng cultivars. The root weight of American ginseng was heavier than others, but that of Russian ginseng was lighter. The num ber of leaflets per plant of 2-year-old plant and the root weight of 6-year-old plant were increased in order of Russian ginseng, American ginseng, Mimaki, Yellow-berry variant and Violet-stem variant.

  • PDF