• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.533-537
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• 2013

Space telescope optics is one of the major parts of any space mission used to observe astronomical targets or the Earth. This kind of space mission typically involves bulky and complex opto-mechanics with a long optical tube, but attempts have been made to observe a target with a small satellite. In this paper, we describe the optical design of a reflecting telescope for use in a CubeSat mission. For this design we adopt the off-axis segmented method for astronomical observation techniques based on a Ritchey-Chr$\acute{e}$tien type telescope. The primary mirror shape is a rectangle with dimensions of $8cm{\times}8cm$, and the secondary mirror has dimensions of $2.4cm{\times}4.1cm$. The focal ratio is 3 which can yield a 0.383 degree diagonal angle in a $1280{\times}800$ CMOS color image sensor with a pixel size of $3{\mu}m{\times}3{\mu}m$. This optical design can capture a ${\sim}4km{\times}{\sim}2.3km$ area of the earth's surface at 700 km altitude operation.

• 한국항공우주학회지
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• 제42권1호
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• pp.90-97
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• 2014

본 논문에서는 Ka대역에서 무궁화 5호와 통신이 가능한 지상 단말 안테나를 설계하였다. 선정한 안테나는 반사판 형상으로 주요 구성품은 높은 이득과 효율을 갖는 이중 옵셋 그레고리안 타입의 반사판과 낮은 부엽을 갖는 코러게이트 혼, 원형편파 생성을 위한 주름형 편파기와 송수신 신호 분리를 위한 직교 모드 변환기로 구성된다. 설계 안테나는 위성과의 통신을 위하여 Ka대역에서 송신 LHCP 이득 45.7dBi 이상, 수신 RHCP 이득 42.0dBi 이상으로 구현하였고, 주편파와 교차편파의 부엽준위는 국제통신연합에서 고정 위성 업무에 대해 권고하는 ITU-R S. 580-6와 731-1을 만족하도록 설계하였다. 마지막으로 축비 성능은 MIL-STD-188-164A에서 권고하는 송신 1.0dB, 수신 1.5dB 이하로 설계하였다.

• Journal of Korean Biological Nursing Science
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• 제19권1호
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• pp.38-47
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• 2017

Purpose: This study was undertaken to examine the relationship between airflow obstruction and subjective health status reported by stable patients with chronic obstructive pulmonary disease (COPD) residing in the community. Methods: A cross-sectional descriptive study was conducted with 78 stable COPD patients aged 69.7 years old on average and selected by a convenient sampling from an outpatient department of pulmonology in tertiary hospitals. They completed a constructed questionnaire including general characteristics, smoking history, dyspnea by modified medical research council (mMRC) scale, and health status by COPD assessment test (CAT). Anthropometric measurements were performed for body mass index (BMI) and pulse oxymetry for $O_2$ saturation (Sat $O_2$). Medical records were reviewed to obtain disease-related characteristics including duration of the disease, cardiovascular comorbidity, and forced expiratory volume in 1 second ($FEV_1$). Data were analyzed using PASW statistics 20.0. Results: Mean $FEV_1%$ and CAT scores were 55.11% and 17.73, respectively. Those in the lower stage of mMRC showed significantly higher $FEV_1$ and lower CAT. $FEV_1$ and CAT showed significant negative correlations; age and BMI with $FEV_1$, and Sat $O_2$ with CAT. Conclusion: The findings suggest that the less airway obstruction was, the better health status was, and provide the support for using subjective measures in clinical practices for COPD patients.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.244-247
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• 1999

In this paper, a low voltage CMOS analog four-quadrant multiplier is presented. The proposed multiplier is composed of a pair of transconductor and lowers supply voltage down to $V_{T}$+2 $V_{Ds,sat}$+ $V_{DS,triode}$. The designed analog four-quadrant multiplier have simulated by HSPICE using 0.25${\mu}{\textrm}{m}$ n-well CMOS process with a 1.2V supply voltage. Simulation results show that the THD can be 1.28% at maximum differential input of 0.7 $V_{p-p}$././.

• 대한임상독성학회지
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• 제9권1호
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• pp.8-13
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• 2011

Purpose: Although glyphosate-surfactant herbicide intoxication is relatively mild toxic in humans, we encountered an atypical clinical presentation. We performed this study to understand the atypical clinical course and factors associated with severe intoxication after glyphosate ingestion. Methods: We conducted a retrospective study of 61 patients (male 43, mean age $54{\pm}18.8$ years) who were presented with glyphosate ingestion between March 1997 and March 2011. The severe intoxication group was defined as patients with systolic blood pressure less than 90 mmHg, respiratory distress needing intubation, or altered mental state. Results: Of the 61 patients, 22 patients (36.1%) had a severe clinical course, 1 patient (1.6%) had died and 1 patient (1.6%) had moribund discharge. The most common symptoms were nausea with or without vomiting which occurred in 30 patients (49.2%). Twenty-seven patients had metabolic acidosis that was the second most common medical complication. Advanced age, pH, base excess, $HCO_3$, Sat, creatinine, X-ray abnormalities and ECG abnormalities were significant factors. Hemoglobin, platelet, $pO_2$, $pCO_2$, BUN, sodium, potassium and AST levels were not different comparing the laboratory characteristics between the severe and mild intoxication groups. Conclusion: The results of this study showed that severe intoxication occurred in 22 patients (36.1%) after glyphosate intoxication. Advanced age, pH, base excess, $HCO_3$, Sat, creatinine, X-ray abnormality and ECG abnormalities were significant predictive factors for severe intoxication in patients with glyphosate surfactant herbicide poisoning.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.28-29
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• 2006

The magnetic properties of a series of both annealed and as-rolled Ni-$W_y$ alloy tapes with compositions y = 0, 1, 3, and 5 at.%, were studied. To compare with Ni-W alloys, the magnetic properties of a series of both annealed and as-rolled $[Ni_{97at.%}W_{3at.%}]_{100-x}Cu_x$ alloy tapes with compositions x = 0, 1, 3, 5 and 7 at.%, were studied, as well. Both the isothermal mass magnetization M(H) of a series of samples, such as both Ni-W and [Ni-W]-Cu alloy tapes, at different fixed temperatures and M(T) in fixed field, were measured using a PPMS-9 (Quantum Design). The degree of ferromagnetism of Ni-$W_y$ alloys have reduced as W-content y increases. Both the saturation magnetization $M_{sat}$ and Curie temperature $T_c$ decrease linearly with W-content y, and both $M_{sat}$ and $T_c$ go to zero at critical concentration of $y_c$ ~ 9.50 at.% W. The effect of Cu addition on both the saturation magnetization $M_sat$ and Curie temperature $T_c$ decrease linearly with Cu-content x in $[Ni_{97at.%}W_{3at.%}]_{100-x}Cu_x$ alloy tapes with compositions x = 0, 1, 3, 5, and 7 at.%. The results confirm that [Ni-W]-Cu alloy tapes can have much reduced ferromagnetism as Cu-content x increases.

• Journal of Radiation Protection and Research
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• 제38권1호
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• pp.1-9
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• 2013

교육훈련은 안전문화를 증진하고, 방사선작업종사자의 방사선방호 역량을 강화하는 주요한 수단이다. 기존의 단기 원자력 국제교육은 고위급 대상의 강의실 교육을 중심으로 수행되고 있으나, 이제 원전을 수출하는 기술공여국으로서 우리의 위상은 개도국으로부터 자국의 실무 전문가 양성을 위한 지원을 요청받고 있다. 본 연구는 국내의 우수한 방사선 시설과 교육훈련 인프라를 활용하여 실습과 현장방문을 강화한 국제 방사선방호 실무 전문가 양성 과정을 개발하고, 평가 및 피드백 절차를 완성하여 운영한 결과를 요약한다. 교육과정의 개발 및 운영 과정에서는 SAT 방법론을 도입함으로써 교수-학습 효과를 극대화하고, 교수목적, 방법, 평가의 일관성을 유지하고자 하였다. 교육과정의 개시전 또는 종료 후에 수행된 비교평가와 최종평가에서 평균 점수가 약 2점 상승하고, 설문조사에서는 대부분의 항목에서 4.0 이상의 높은 만족도를 나타내었다. 이는 본 교육과정에 적용된 교수학습 방법이 효과적이었음을 시사한다. 이러한 교수학습 방법론은 국제교육에서 실무 전문가 양성을 위한 맞춤형 교육과정을 개발하고, 이론중심에서 현장 실무중심으로 국제교육의 패러다임을 전환하는 단초가 될 것이다.

• Journal of applied mathematics & informatics
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• 제31권1_2호
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• pp.155-164
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• 2013

In this paper, we have established some common fixed point theorems for two pairs of occasionally weakly compatible hybrid maps sat-isfying a strict contractive condition in a non-archimedean fuzzy metric space. Our result extend, generalized and fuzzify several fixed point theo-rems on metric space.

• 정보와 통신
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• 제29권6호
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• pp.34-40
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• 2012

본고에서는 최근 전세계적으로 이슈가 되고 있는 그린 네트워크 연구를 주도하고 있는 국제 산학연 콘소시움인 그린터치를 소개한다. 그린터치는 2015년까지 현재 네트워크의 에너지 효율성을 1,000배 향상시킨다는 목표 아래 전체 네트워크에 대한 연구를 진행 중이고, 2개의 핵심 기술에 대한 데모를 성공적으로 시연하였다. 본고에서는 SAT 위원회와 네트워크 위원회 산하 Core Optical Networking & Transmission, Core Switching & Routing, Mobile Communications, Wireline Access 워킹 그룹별로 현재 진행 중인 프로젝트를 살펴본다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권1호
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• pp.61.2-61.2
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• 2009