• 제목/요약/키워드: retro

검색결과 320건 처리시간 0.025초

실내용 자유 공간 광 통신을 위한 수신단의 위치 탐색 및 자동 링크 정렬 방법 (Searching and Autoalignment Method for Indoor Free-space Optical Communication)

  • 이관용;조승래;이창희
    • 한국광학회지
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    • 제30권6호
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    • pp.230-236
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    • 2019
  • 저렴한 retro-반사지와 미소 전자 기계 시스템(micro electro-mechanical system, MEMS) 거울을 이용한 실내용 무선 광 통신용 위치 탐색 및 자동 링크 정렬 방법을 제안하고 실험하였다. 직접적인 가시선(line of sight, LOS) 확보를 위하여 retro-반사지에서 돌아온 빛으로부터 수신단 위치를 파악하고 MEMS 거울을 통한 빔 조종으로 통신 링크를 자동 정렬하였다. 자동 정렬된 광 링크를 통하여 7 m 전송 거리에서 2.5 Gb/s NRZ 신호를 전송하여 비트 에러율 10-12에서 수신 감도 -31.87 dBm의 성능을 가졌다.

시판 야간 안전복의 기능성 및 가시성 평가 (Evaluation of the Functionality and Visibility of Commercial High-Visibility Clothing for Nighttime Usage)

  • 이현영
    • 한국생활과학회지
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    • 제19권6호
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    • pp.1053-1062
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    • 2010
  • To assist the further development of hight-visibility clothing this study compared the visibility and subjective wear sensation of commercial protective vests with retro-reflecting materials or LEDs. Nine subjects compared high-visibility vests to evaluate how easy they were to see when exposed to the headlight of a car at night, and the subjects assessed the wear sensation of the vests also. The intensity and visibility of five different colored LEDs assembled on the five substrates separately were also evaluated to select the suitable LED color for night protective clothing. The intensity of illumination was measured by an illuminometer, and the visibility was evaluated by 11 participants both in a dark room and in front of a car outdoors at night. Results showed, the most effective LEDs were high intensity LEDs which shift blinking red and white were most effective. However, excessively high intensity of illumination could decrease the working efficiency. In subjective wear evaluation, the most favorable vest had a front opening, were adjustable at the sides, and had an electric power switch on the front of the vest.

현대패션의 로맨틱 이미지에 관한 연구 (A Study on the Romantic Image in Modern Fashion)

  • 김영현;양취경
    • 복식
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    • 제55권1호
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    • pp.1-12
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    • 2005
  • The modern society which is going through the big turbulence of civilization experiences the lost of humanity and the phenomenon that the standard of our thoughts, like those for good and evil, truth and false is not clear anymore as the technology is being improved. This makes us miss the past when everything is simple and the standards are very clear and being attracted by the metaphorical culture symbolizing something from the past, like memories of youth, fantasies, fairy tales or myths and we are now having a great interest in the joy of life and the affluent life. Influenced by this kind of tendency in modern society, the minimalism, which had the great influence in the nineties, went out of fashion and at last the romantic susceptibility seems to be the trend forming the major mood of the late 20th century - the early 21st century. This study focus is: (1) the theoretical aspects of romantic images such as the concept, the historical tendency and the character are considered. (2) the variety and multiplicity of the romantic images is discussed after the romantic image is classified into four types of retro character, natural character, ethnic character, erotic character according to major trends in our modern. The purpose of this study is to understand the romantic images in modern fashion, by analyzing the fashion trends together with the various features of romantic images.

분자궤도론에 의한 반응성 결정 (제32보). 3-부테노산의 기체상 탈탄산반응에 미치는 치환기 효과의 분자궤도론적 연구 (Determination of Reactivity by MO Theory (Part 32). MO Studies of Substituent Effects on the Gas-Phase Decarboxylation of But-3-enoic Acid)

  • 조정기;이익춘;오혁근;조인호
    • 대한화학회지
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    • 제28권5호
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    • pp.279-283
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    • 1984
  • but-3-enoic acid의 retro-ene 탈탄산 반응에 있어서 그 반응성에 대한 ${\beta}$-치환기 효과를 이론적으로 연구하였다. 그 결과 전하 효과에서, 실험에서의 치환체에 의한 ${\pi}$-전자 전달만이 관여되는 것이 아니라, $CH_3$-치환같은 경우는 편극 효과도 상당히 관여됨을 알 수 있었다. 그러나 이들 반응성을 전하 효과로만 결정지을 수 없으며, HOMO와 LUMO간의 에너지 간격이 또한 반응성에 크게 영향을 미친다. 결과적으로, 일반적으로 논하는 치환체의 ${\pi}$-전자 주게 능력이 클수록 반응이 빨라진다는 사실에는 변함이 없었다.

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SLR을 이용한 GPS-36 위성의 정밀 궤도 결정 (PRECISE OR81T DETERMINATION OF GPS-36 SATELLITE USING SATELLITE LASER RANGING)

  • 임형철;박관동;박필호;박종욱;조정호
    • Journal of Astronomy and Space Sciences
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    • 제19권4호
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    • pp.385-394
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    • 2002
  • SLR(Satellite Laser Ranging)은 위성과 관측소간 거리를 가장 정밀하게 측정할 수 있는 시스템이다. 1964년 발사된 Beacon-B 위성의 궤도결정을 위해 SLR 기술이 처음 사용되었는데 거리측정 정밀도가 m 수준이었다. 현재 single shot 정밀도는 cm, NP(Normal Point)는 mm수준으로 발전하였다. 이 연구에서는 SLR을 이용한 궤도결정 알고리즘을 개발하여 GPS(Global Positioning System)-36위성의 정밀 궤도를 결정하였다. 알고리즘의 정밀도를 검증하기 위해 산출한 정밀 궤도를 IGS(International GPS Service)에서 제공하는 정밀 궤도력과 비교하였는데 74cm의 RMS(Root Mean Square)를 얻었다. 또한, SLR 시스템의 관측잔차 RMS는 55mm 미만으로 알려져 있지만 이 연구에서는 44mm 결과를 얻을 수 있었다.

Effects of calcium silicate cements on neuronal conductivity

  • Derya Deniz-Sungur;Mehmet Ali Onur;Esin Akbay;Gamze Tan;Fugen Dagli-Comert;Taner Cem Sayin
    • Restorative Dentistry and Endodontics
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    • 제47권2호
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    • pp.18.1-18.9
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    • 2022
  • Objectives: This study evaluated alterations in neuronal conductivity related to calcium silicate cements (CSCs) by investigating compound action potentials (cAPs) in rat sciatic nerves. Materials and Methods: Sciatic nerves were placed in a Tyrode bath and cAPs were recorded before, during, and after the application of test materials for 60-minute control, application, and recovery measurements, respectively. Freshly prepared ProRoot MTA, MTA Angelus, Biodentine, Endosequence RRM-Putty, BioAggregate, and RetroMTA were directly applied onto the nerves. Biopac LabPro version 3.7 was used to record and analyze cAPs. The data were statistically analyzed. Results: None of the CSCs totally blocked cAPs. RetroMTA, Biodentine, and MTA Angelus caused no significant alteration in cAPs (p > 0.05). Significantly lower cAPs were observed in recovery measurements for BioAggregate than in the control condition (p < 0.05). ProRoot MTA significantly but transiently reduced cAPs in the application period compared to the control period (p < 0.05). Endosequence RRM-Putty significantly reduced cAPs. Conclusions: Various CSCs may alter cAPs to some extent, but none of the CSCs irreversibly blocked them. The usage of fast-setting CSCs during apexification or regeneration of immature teeth seems safer than slow-setting CSCs due to their more favorable neuronal effects.

재귀반사체를 이용한 지하시설물 위치측정 타깃의 정확도 분석에 관한 연구 (A Study on the Accuracy Analysis of Position Measurement Target for Underground Facilities by Retro-reflection)

  • 민관식;김재명;최윤수
    • Spatial Information Research
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    • 제21권1호
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    • pp.45-52
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    • 2013
  • 최근 도심기반 지하시설물 정보에 대한 체계적인 관리를 위해 현장시공 시 되메우기 전에 시설물에 대한 3차원 측량을 권장하고 있다. 시설물에 대한 정확한 위치측정 요구 증가와 함께 보다 신속하고 정확하게 각종 지하시설물의 DB 구축을 위해서는 타깃을 포함한 측량방법의 간소화로 비용의 절감 및 데이터 구축의 일관성을 유지할 필요성이 있다. 본 연구에서는 지하시설물 DB 구축을 위한 시설물 위치측정 방법으로 현재 측량에 이용되는 광학프리즘의 재귀반사 원리를 이용하여 최적의 반사체 타깃을 제작(삼각형, 사각형 및 반구형)하여 현장에서 측량자에 의해 되메우기 전에 위치측정을 수행할 수 있는 새로운 유형의 측량타깃을 개발하는데 목적이 있다. 새로운 측량타깃은 지하시설물 측량이 가능하고 데이터의 신뢰성 및 정확도 확보를 위해 유형별로 토털스테이션 측량좌표와의 정량적 비교를 통하여 위치 측정의 정확도를 비교하여 보았다. 연구결과 시설물 위치측정을 위한 반사체 타깃의 유용성을 입증 하였으며 새로운 타깃의 사용으로 보다 신속하고 정확하게 측량자에 의해 지하시설물 DB 구축을 위한 3차원 위치를 획득할 수 있는 기반을 마련하였다.

패션에 있어서 시간성이 반영된 룩에 관한 고찰 (A Consideration of Look Reflecting Time in Fashion)

  • 주미영;김영인
    • 복식
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    • 제56권6호
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    • pp.1-15
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    • 2006
  • The purpose of this study is to present a new viewpoint in look by closely examining fashion and look through the past, present, and future. Specifically, the concept of time is studied and fashion is considered based upon the concept of time, finally, looks in fashion related to time are analysed. For this study, the literature of retro, modern, contemporary, futuristic looks that express the past, present, and future, and the classic look, the popularity of which transcends the concept of time was considered focusing on 20th century women's fashion. Design characteristics of these looks were analyzed utilizing photographs of collection images. The results of the study are as follows: first, although the retro look of different periods regularly rotate and appear, they change and develop in new and various ways depending on the Periodic background of the time they appear in, and thus show simultaneously the cyclical and straight nature of time. Second, the modern look includes not only the moaning of time concept of the present, but also of interpreting anew the formal significance of modernism in the present. In other words, because it cyclically repeats the times of past modern periods, the look can be said to focus on the cyclical nature of time. Third, the contemporary look is a style that expresses current time most exactly as it exists, and it can be said to be the look in which current time is most vividly expressed. Fourth, the time concept in futuristic look is a subjective time that selectively accommodates and expresses the objective time of the future which has not yet come, and that can be the look's most important point. Last, the classic look possesses an objective value that transcends the concept of time, and it keeps returning, showing the cyclical nature of time. The closer this study came to the present, it could be seen that a look communicated more complex meanings, Influenced by periodic phases such as diversification, individualization, and eclecticism, and that while it could not be defined as any one look, various elements were expressed eclectically by being mixed and matched with each other, and it could utilize more natural forms, colors, and materials.

눈둘레근뒤 지방과 앞사이막 지방 단위의 재배치술을 통한 눈썹하 절제술 (Sub-brow Resection via Relocation of Retro-orbicularis Oculi Fat and Preseptal Fat Unit)

  • 차정호;우상민;김진우;정재학;김영환;선욱
    • Archives of Plastic Surgery
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    • 제38권4호
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    • pp.477-484
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    • 2011
  • Purpose: Retro-orbicularis oculi fat (ROOF) and preseptal fat pad (PSF) are deep fat structures of frontal and supraorbital area, that encounter galeal fat pad (GFP). If galeal wall is weakened by aging process, GFP loses its anchoring structure, moved downward pushing ROOF and PSF. This especially occur in lateral brow area. As a result of drooping, eyebrow affects the eyelid covering PSF as a sac descended to a lateral hooding and ptotic eyelid simultaneously. Consequently, in the case of lateral hooding and brow ptosis, besides the skin, deep fat structures (ROOF and PSF) should be corrected as well. Methods: ROOF-PSF repositioning technique in subbrow resection were performed. 21 cases of patients from April, 2007 to January, 2008. Before surgery, all patients were examined carefully to evaluate the degrees of dermatochalasia, drooping of the eyebrow, marginal reflex distance 1 (MRD1), eyelid crease height. Surgery was performed under local anesthesia, then excised the drooped eyelid skin by lateral subbrow resection, removed proper amount of ROOF, repositioned ROOF-PSF at the supraorbital rim, and fix it on periosteum. During follow up periods, the patients were surveyed of the satisfaction of surgery, and postoperative MRD1 was evaluated. Results: One patient had a hematoma on left eyebrow, and another one patient had a numbness on left forehead for two months. Except for these two patients, all patients had good results without any significant complications. The mean follow up period was about 5 months, and the position of lateral eyebrow maintained above the supraorbital rim in all cases. Postoperatively, MRD1 increased by 0.8 mm in 5-months mean follow up period. Conclusion: In patient with lateral brow ptosis and lateral hooding, the ROOF-PSF repositioning technique in sub-brow resection could be a good operative option.

Four Species of Jumping Spiders (Areaneae: Salticidae) from China

  • Xian-Jin Peng;Joo-Pil Kim
    • Animal cells and systems
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    • 제2권4호
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    • pp.411-414
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    • 1998
  • One novel species, Phaeacius yunnanensis n. sp. and three species new to China, Brettus albolimbattus, Hyllus lacertosus and Ptocasius kinhi of the jumping spider.belonging to the family Salticidae, are described based on the materials collected from Yunnan Province, China. The new species is similar to Phaecius lancerarius, but can be distinguished by secondary conductor covers on the emblus. That of the latter below the emblous, retro1aterial tibial apophysis, is much more slender and with an abdominal pattern.

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