• 한국전자파학회논문지
• /
• 제26권6호
• /
• pp.555-563
• /
• 2015

본 논문에서는 주파수 변조 연속파(FMCW) 전파고도계의 신호처리 알고리즘 및 실용적인 평가방안을 제안한다. 전파 고도계는 초기에 탐색모드로 동작하여 고도를 탐색하고, 유효한 고도가 탐색되면 추적모드로 전환되어 측정된 고도를 표시한다. 고도 탐색/추적 시 기준고도 또는 추적고도에 따라 변조대역폭을 제어함으로써 비트 주파수 대역폭을 제한하며, 송신출력과 수신이득의 제어를 통해 고도 변화에 따라 늘어난 수신 전력의 동적 범위를 보상하도록 설계하였다. 개발된 전파고도계의 성능은 더욱 실제적인 환경에서의 크레인 시험을 통해 신호처리 알고리즘의 동작과 낮은 측정오차를 성공적으로 검증하였다.

• 디지털콘텐츠학회 논문지
• /
• 제8권3호
• /
• pp.355-363
• /
• 2007

학습자의 성격유형에 따른 학습 선호도는 학습 성취의 주요 인자 중의 하나이다. 따라서 학습자는 자신의 성격 유형과 다른 콘텐츠로 학습을 하게 되면 스트레스가 증가하여 혈압이나 심박동수에 변화가 나타나게 된다. 본 연구에서는 학습자의 비선호도를 측정하기 위해서 스트레스 량 측정에 사용되는 주파수 영역 정보를 이용하였다. 먼저, 13명의 유치원 아동들을 MBTI 성격유형의 감각/직관의 두 유형으로 파악하고 이들에게 동일한 학습 콘텐츠를 10분간 제시한 후, 이를 학습하는 동안 측정된 심전도 신호를 심박변동신호(heart rate variability: HRV) 신호로 재구성하였다. 이 HRV 신호를 주파수로 변환한 후에 저주파(LF: low frequency), 중간 주파(MF: middle frequency), 그리고 고주파(HF: high frequency) 영역으로 분할하고, 각 주파수 영역비를 비교하여 학습자의 성격 유형에 따라 학습 콘텐츠에 대한 선호도가 달라지는 지 여부를 알아보았다. 실험 결과는 아동들은 자신의 성격 유형에 따라 각기 다른 학습 콘텐츠를 선호한다는 사실을 보여준다.

• 인문언어
• /
• 제5권
• /
• pp.167-192
• /
• 2003

When Hart Crane′s poem cycle The Bridge was published in 1930, a group of influential reviewers accused Crane of immaturity, sentimentality, and lack of focus. They condemned crane′s wayward, fuzzy mysticism as backwards-looking and self-defeating. Even sympathetic critics, such as Harold Bloom, have consistently portrayed Crane′s poetry as the pyrotechnic final fizzle of late romanticism. These persistent, public reservations, however, have not prevented an impressive proliferation in secondary literature concerning Crane since the late 1960s. His promiscuity, alcoholism, erratic behavior, relative poverty, tragic death, and total commitment to art have since earned him the labels of New World Rimbaud and proto-Beat. His colorful career thus explains in part his retrospective fame. Nevertheless, living hard and dying young do not guarantee artistic immortality. This article poses questions as to why Crane has mattered so much to subsequent generations of U.S. readers and what these readers find so compelling in his poetry. The answer, I would argue, lies in Crane′s idiosyncratic use of language. Far from striving for transparency, he writes in an inimitably obstructive, artificial manner. There is something seductive and absurd in his wild use of words here, I would further argue, we discover the reason behind both Crane′s enduring appeal and his supposed inadequacy as a writer. Crane did "torture" syntax, semantics, and conventional associations, not because he saw his unusual language as an eccentric mannerism but because he saw it as a tool in the service of constructing a "myth of America" and reintegrating the human and divine. Understanding thy he considered this to be the case clarifies Crane′s achievement and illuminates why his work still seems so relevant today.

• 한국광학회지
• /
• 제13권6호
• /
• pp.543-547
• /
• 2002

9.2GHz 주파수 차이로 위상잠금(phase-locking)된 레이저 시스템을 제작하여 그 특성을 조사하였다. 외부공진기 다이오드 레이저 2대를 제작하고, 두 레이저가 9.2GHz 주파수 차이를갖도록 디지털 회로를 이용하여 위상잠금 하였다. 위상잠금된 두 레이저의 맥놀이 신호의 스펙트럼을 측정하였으며, 이로부터 신호의 반송률이 약 93%임을 알 수 있었다. 위상잠금된 두 레이서의 상대 선폭은 2Hz 이하였다. 위상잠금된 두 레이저의 맥놀이 신호의 위상잡음을 측정하였으며, 측정된 위상잡음 스펙트럼으로부터 적분시간 1s 이하에서 상대적인 주파수 안정도를 계산하였다. 적분시간 1s 이상에서는 주파수 측정방법으로 상대적인 주파수 안정도를 측정하였는데, 적분시간 20s 에서 알란편차는 $2.7{\times}10^{-19}$였다.

• 디지털융복합연구
• /
• 제15권1호
• /
• pp.381-391
• /
• 2017

바이오인식 기술은 개인의 고유한 특성인 신체적 또는 행동적 특징을 이용해 사용자를 인증하는 기술이다. 현재 금융, 보안, 출입관리, 의료복지, 공공, 검역, 엔터테인먼트 등 광범위하게 그 필요성 및 효용성으로 서비스 범위가 확대되고 있는 추세이다. 지문, 얼굴과 같은 생체정보를 이용한 바이오인식은 위조, 변장 위협에 노출되어 사회적 문제가 되었다. 최근 신체 외부의 생체정보가 아닌 신체 내부의 생체신호를 이용한 연구가 진행되고 있다. 이에 따라 본 논문에서는 생체신호인 심전도, 심장음, 뇌전도, 근전도를 이용한 바이오인식 시스템의 최근 연구 및 기술들을 분석하고 발전 방향을 위해 필요한 기술들을 제시하고자 한다. 향후에는 개개인의 복합적 상태에서 생체신호 기반 빅 데이터를 관리하는 데이터베이스 구축, 빅 데이터를 분석하는 딥러닝을 이용하여 실시간 환경에 적합한 바이오인식 시스템 기술들이 연구될 것으로 예상된다.

• Nuclear Engineering and Technology
• /
• 제16권1호
• /
• pp.11-17
• /
• 1984

매우 작은 규모의 냉각재 상실 사고후($\leq$0.05ft$^2$) 어떤 일이 일어나는 가를 더 잘 이해하기 위해 고리 1호기에 대한 샘플 계산을 수행하였다 깨진 크기가 0.006 ft$^2$ 보다 큰 사고에 대해서는 냉각재 상실이 보충되는 양을 초과한다. 0.008 ft$^2$ 보다 큰 깨진 크기에 대해서는 잔열은 깨진 곳을 통해 완전히 제거된다. 이와 같은 결과에 비추어 고리 1호기는 매우 작은 규모의 냉각재 상실 사고의 전 영역에 걸쳐 비교적 안전하다고 결론지었다. 하지만, 900MWe 나 1200MWe 를 가진 원자로에 있어서, 어떤 깨진 크기에 대해서는 이 사고가 주의깊게 고려되어야 한다. 자연 순환에서 pool boiling 으로 또는 pool boiling에서 자연 순환으로 천이할때, 특별히 운전자와 안전 분석에 문제점을 남긴다. Primary pump shutoff, HPI pump shutoff, break isolation, opening relief valve의 운전자 간섭에 대해서도 논의 되었다. Shutoff 후 HPI pump의 연속적인 운전은 primary system의 건전성을 위협하지 않는다는 것이 증명되었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.394-394
• /
• 2013

The spin-orbit interaction has received great attention in the field of spintronics, because of its property and applicability. For instance, the spin-orbit interaction induces spin precession which is the key element of spin transistor proposed by Datta and Das, since frequency of precession can be controlled by electric field. The spin-orbit interaction is classified according to its origin, Dresselhaus and Rashba spin-orbit interaction. In particular, the Rashba spin-orbit interaction is induced by inversion asymmetry of quantum well structure and the slope of conduction band represents the strength of Rashba spin-orbit interaction. The strength of spin-orbit interaction is experimentally obtained from the Shubnikov de Hass (SdH) oscillation. The SdH oscillation is resistance change of channel for perpendicular magnetic field as a result of Zeeman spin splitting of Landau level, quantization of cyclotron motion by applied magnetic field. The frequency of oscillation is different for spin up and down due to the Rashba spin-orbit interaction. Consequently, the SdH oscillation shows the beat patterns. In many research studies, the spin-orbit interaction was treated as a tool for electrical manipulation of spin. On the other hands, it can be considered that the Rashba field, effective magnetic field induced by Rashba effect, may interact with external magnetic field. In order to investigate this issue, we utilized InAs quantum well layer, sandwiched by InGaAs/InAlAs as cladding layer. Then, the SdH oscillation was observed with tilted magnetic field in y-z plane. The y-component (longitudinal term) of applied magnetic field will interact with the Rashba field and the z-component (perpendicular term) will induce the Zeeman effect. As a result, the strength of spin-orbit interaction was increased (decreased), when applied magnetic field is parallel (anti-parallel) to the Rashba field. We found a possibility to control the spin precession with magnetic field.

• 한국근적외분광분석학회:학술대회논문집
• /
• 한국근적외분광분석학회 2002년도 강연요지집
• /
• pp.59-62
• /
• 2002

Wavelength selection and prediction algorithm for determining hematocrit are investigated. A model based on the difference in optical density induced by the pulsation of heart beat is developed by taking approximation of Twersky's theory on the assumption that the variation of blood vessel size is small during arterial pulsing[1]. A device is constructed with a five-wavelength LED array as light source. The selected wavelengths are two isobestic points and three in compensation for tissue scattering. Data are collected from 549 out-patients who are randomly grouped as calibration and prediction sets. The range of percent hematocrit was 19.3∼51.8. The ratio of the variations of optical density between systole and diastole at two different wavelengths is used as a variable. We selected several such variables that show high reproducibility among all variables. Multiple linear regression analysis is made. The relative percent error is 8% and the standard deviation is 3.67 for the calibration set. The relative % error and standard deviation of the prediction set are 8.2% and 3.69 respectively. We successfully demonstrate the possibility of non-invasive hematocrit measurement, particularly, using the wavelengths below 1000nm.

• 대한물리치료과학회지
• /
• 제3권1호
• /
• pp.835-841
• /
• 1996

The purpose of this study is to investigate the relationship between the development of laterality and bilateral motor abilities measured with respect to various rhythm movements in upper extremity of mentally retared children. The development of laterality was measured by a survey of dominace-hand. The bilateral motor abilities were assessed by means of a tentative rhythm beat test of hands. One hundred sixty eighty subjects with special education needs shose age ranged from 7 to 18 years old were used for an experimental group. Fity nine normal children whose age ranged from 3 to 6 years old were also chosen as a control group. The major findings were a follows: 1. The development of lateral dominace-hand in mentally retared children differed from that of normal subjects with as increase in chronological age; the degree of the attainment of lateral dominance - hand was 75 percest of the mean level of the normal children. Though normal children establish a dominance - hand by ths age of years old, meatally retarded children are likely to show 57 percent of normal development at the age of 7 through 9 years old and 65 percent of normal development at the age of 16 through 18 years old. 2. A greater delay in mentally retarded was found through a rhythm test which was development to assess bilateral motor abilities in upper extremity. A closser relationship betwin chronological age and the development of bilateral motor abilities in mentally retared children was found. 3. In view of these findings, it was indicated that bilateral motor abilities of the retarded and non-retarded children were significantly correlated to the acqusition of dominance-hand.

• 동아시아식생활학회지
• /
• 제10권6호
• /
• pp.548-559
• /
• 2000

This study was carried out through questionnaire in order to investigate the self-recognized monosodium glutamate (MSG) symptom complex in the eating out of housewives. The subjects were 503 housewives in Inchon and the results are summarized as follows. As for age, 51.9% of subjects were over 40 years old. Also 60.0% of the subjects received a high school education. As for occupation, full-time housewives accounted for 63.7%. Monthly household income of most subjects were 1 million won or more, and monthly food expenses for most subjects were over 300 thousand won or more. Also 71.0% of the subjects lived in apartments. As for frequency of eating out, 69.5% of subjects ate out I~2 times a month, 21.6% did 3~4 times a month, 4.5% did 7 times or more/month and 3.6% did 5~6 times a month. The higher education level, family income or food expense of subjects were, the more they ate out. Most subjects selected the menu of eating out according to preference of family. Also 63.6% of the subjects considered the amount of MSG in eating out. As for menus containing high amount of MSG, 55.8% of subject answered Korean dishes, 31.1% did Chinese dishes. After eating out, 25.1% of subjects perceived MSG symptom complex, such as thirst, tiredness and rapid heart beat, etc. Therefore, it may be necessary to reduce the amount of MSG in eating out and to develop safe and delicious menus of eating out using various natural foods.