• 한국전자파학회논문지
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• 제20권8호
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• pp.721-728
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• 2009

본 논문에서는 기판 집적 도파관(Substrate Integrated Waveguide: SIW) 기술을 이용한 위성통신용 전력 분배기를 제안하였다. 출력 구형 도파관의 크기를 변화시키지 않고, 가이딩 포스트의 위치를 조절하여 등분 비등분의 전력 분배 비율을 조절하였다. 또한, 방사형 도파관의 기본적인 특성과 입력부, 전력 분배의 과정을 자세히 설명하였다. 방사형 도파관의 신호 여기 방법으로 전류 프로브를 사용하여 동축 케이블로 구현하였으며, 출력부는 마이크로스트립 선로를 천이 구조를 이용하여 SMA 커넥터를 이용하였다. 설계된 4분기 전력 분배기는 등분/비등분으로 동작할 수 있으며, 설계 결과를 시뮬레이션과 제작으로 검증하였다. 등분/비등분 전력 분배기의 측정된 결과는 VSWR 2:1을 기준 대역특이 약 2.1 GHz와 3 GHz이다.

• 한국전자통신학회논문지
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• 제10권4호
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• pp.441-448
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• 2015

본 논문에서는 WLAN 시스템에 적용 가능한 이중 대역을 갖는 안테나를 설계, 제작 및 측정 하였다. 제안된 안테나는 CPW 급전 구조를 바탕으로 두 개의 선로로 구성되어 있으며 두 개 분기 선로의 길이 조정을 통해 이중 대역 특성을 갖도록 설계하였다. 최적화된 수치를 얻기 위해 상용 툴인 HFSS을 사용하여 $L_5$, $L_8$, $W_3$, $W_5$, $W_9$ 파라미터에 대한 시뮬레이션을 수행하였다. 제안된 안테나를 얻어진 최적화된 수치를 사용하여 FR-4 기판위에 제작하였다. -10dB 임피던스 대역폭을 기준으로 반사손실에 대한 측정결과, 2.4 GHz 대역에서 1,095 MHz (1.57~2.665 GHz) 그리고 5 GHz 대역에서 1,680 MHz (4.99~6.67 GHz)의 대역을 얻었으며 WLAN에서 요구하는 대역폭을 만족시켰다. 또한 WLAN 대역에서 이득과 방사패턴의 특성을 얻었다.

• 한국전자파학회논문지
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• 제17권5호
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• pp.416-422
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• 2006

본 논문에서는 IEEE 802.11a를 대역을 포함하는 고이득, 광대역 마이크로 스트립 안테나를 설계 및 제작하였다. 마이크로스트립 안테나의 대역폭을 넓히기 위해, 첫째 마이크로스트립 라인-동축 프로브 급전 방법을 사용하였고, 직사각형 패치에 U-Slot을 삽입하였다. 다음으로 안테나의 이득을 향상시키기 위해 $2{\times}2$ 배열 구조를 이용하였다. 측정 결과 입력 반사 손실 VSWR 2:1인 범위가 약 1 GHz($5.110{\sim}6.142$ GHz)의 광대역 특성을 나타내었으며, 측정 이득은 E-plane과 H-plane의 5.15 GHz, 5.35 GHz, 5.50 GHz 그리고 5.85 GHz 모두에서 13 dBi 이상 특성을 나타내었다.

• 대한전자공학회논문지TC
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• 제47권11호
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• pp.84-90
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• 2010

본 논문은 평행결합 선로의 구조를 갖는 크기가 작아진 광대역 대역통과 필터로서 커플링 계수의 양에 따라 협대역에서 광대역 까지 자유롭게 조절이 가능하도록 제안 하였다. 기존의 필터는 구조의 특성상 협대역으로만 동작이 가능한데, 만일 그 이상의 대역폭을 요구하게 된다면 급전선로와 공진기 사이의 커플링 양으로 인해 실제의 구현이 어렵다는 단점을 갖게 된다. 이러한 단점을 극복하고 새로운 방법을 도입했을 때 제안한 필터는 SIR 구조와 복층 형으로 구성되어 있어 기존의 필터 보다 크기가 작아짐은 물론 커플링 계수의 양에 따라 대역폭을 자유롭게 조절이 가능하다는 특징을 갖게 된다. 본 논문에서 최종 제시한 필터는 광대역 필터의 결과로서 중심 주파수 5.8 GHz에서 대역폭 60 %, 그리고 삽입손실과 반사손실은 각각 0.42 dB 및 20.9 dB의 결과 값들을 얻었다.

• 한국생활과학회지
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• 제12권4호
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• pp.463-495
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• 2003

The purpose of this study was to obtain a fundamental data for developing a policy concerning women and child rearing and a parent education program for young parents who are around their childbirth, a period crucially important both for the parents in terms of the role adjustment, career management, and family finance, and for the infants in terms of its physical and psychological well-being. The subjects were 509 mothers before and after childbirth currently living in the Metropolitan City of Daejeon. Data were obtained through questionnaires and interviews in two major areas of pregnancy-delivery-childcare and parent education. Data were analyzed using SAS, mostly through frequency analysis, percentiles, t-tests, and F-tests. Results of descriptive analyses were organized along the following areas and issues: Pregnancy(family planning, regular check-ups, difficulties, prenatal education, costs, etc.); delivery(type of delivery, delivery related experience, costs, clinic/medical institute of choice, worries/problems, help/supports, etc.); postpartum care(place, kinds of help and helper, costs, postpartum care facilities, etc.); childcare circumstances(place, carer, time schedules, childcare centers or facilities feeding and weaning, etc.); husband's attitudes and involvement in the overall process; working mothers(maternity leave, temporary retirement for child rearing, etc.); and, parent education(family planning, pregnancy, delivery, postpartum care, child rearing, areas or issues needing parent education, facilitative and hindering factors to ideal parenting, etc.). Differences between groups of pregnant mothers and postpartum mothers, working- and non-working mothers, groups of different income levels, mothers and fathers of different educational levels, mothers of first pregnancy(or childbirth) and experienced mothers were also analyzed. Several conclusions with suggestions were drawn in relation to the need for strong implementation as well as developing of policies on women and childcare and for developing a new parent education program for parents before and after childbirth.

• 한국수산과학회지
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• 제46권4호
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• pp.445-453
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• 2013

Walleye pollock Theragra chalcogramma fisheries in Korean waters have changed dramatically during the last three decades: the highest catches occurred in 1981, followed by continuous decreases through the 1990s, ending with a complete collapse of the population in the 2000s. The major spawning ground of walleye pollock is located in North Korean waters, and some juveniles (called nogari in Korean, <300 mm) migrate to the south for feeding and growth. Since the 1960s, Korean fishermen have often caught juveniles, and the weight (metric tons) of juvenile catch was recorded from 1975-1997. However, because the walleye pollock were not aged, the population age structure was not delineated. We developed a model to estimate the number of walleye pollock of each size class based on catch statistics of adults and juveniles, the catch proportion of each size class, and length and weight information on specimens collected by Danish-seine and drift-gill-net fisheries. The model results demonstrated that the recruitment size of walleye pollock was consistently within the 200-250mm size class, and the highest number of this size class occurred in 1981, although values greatly fluctuated interannually. The number of juvenile pollock was 10.4 times higher than that of adult pollock during 1975-1997. The total yield of juvenile pollock was 0.95 million tons, which was equivalent to about 68.2% of total pollock production. The number of juvenile pollock caught during the same period, however, was 16 billion, comprising about 91.2% of the total number caught. Such high fishing pressure on juvenile pollock is considered one of the main factors causing the collapse of the pollock population.

• Journal of Nutrition and Health
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• 제39권8호
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• pp.795-800
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• 2006

In order to examine nutritional and behavioral risk factors of atopic dermatitis (AD) in Korean preschoolers, we analyzed data on 144 children aged 3-6 years with AD and their 434 healthy counterparts. The data included breast-feeding history, current weight, food behaviors assessed by the Mini Dietary Assessment (MDA), food intake by a semi-quantitative food frequency questionnaire, and behavior problems by the Preschool and Kindergarten Behavior Scale (PKBS). Multivariate logistic regression analyses were performed after controlling for preschool location and child's age, gender and total energy intake, as appropriate. There was no group difference of child and household characteristics. Breastfeeding history was related to lower AD risk (OR = 0.63, 95% Cl = 0.40-0.99), yet no statistically significant association was found with overweight status. Regarding food behaviors, AD risk was lower in children who drank milk at least one cup per day (OR = 0.52, 95% Cl = 0.35-0.78) and had regular meals (OR = 0.62, 95% Cl =0.42-0.92). Moreover, there were lower risks of AD in the second (OR =0.48, 95% Cl = 0.28-0.82) and the highest (OR = 0.55, 95% Cl = 0.32-0.94) intake quartiles as compared with the lowest quartile of kimchi intake. Similarly, AD risk was lower in the highest quartile of rice (OR = 0.51 Cl = 0.28-0.93) and the second quartile of fruit (OR =0.45, 95% Cl = 0.25-0.82) intakes. AD children had more problems in social interaction (OR = 1.97,95% Cl = 1.26-3.07) and independence (OR = 1.60, 95% Cl = 1.01 -2.54) measures than the healthy controls. Likewise, AD children tended to show more problem behaviors such as anxiety (OR = 1.63, 95% Cl = 0.99-2.69). Our results suggest that nutritional and behavioral dimensions are related to AD risk, yet the case control study design may preclude generalization of these results.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.61-62
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• 2018

본 논문은 동작하는 3.5 GHz 대역(WiMAX)의 광대역 양면 다이폴 안테나에 대해 연구하였다. 다이폴은 유전체 기판의 양면에 인쇄함으로써 쉽게 구현될 수 있고 능동회로와의 접속에 적합하다. 광대역 특성을 얻기 위해 다이폴 안테나의 모양은 두꺼운 직사각형 모양으로 하였다. $50{\Omega}$ 마이크로스트립 급전 선로에 정합 되도록 배열 급전회로와 밸런을 설계하였다. 시뮬레이션을 통해 3.4~3.7 GHz 대역의 안테나를 설계하고 반사손실, 이득, 방사패턴 등의 안테나 특성을 확인하였다. 시뮬레이션 결과 3.5GHz 대역의 최대이득은 5.5 dBi이고 VSWR이 2 미만인 대역폭은 약 1GHz이다.

• 한국임상수의학회지
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• 제16권2호
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• pp.439-442
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• 1999

An animal health monitoring system in Gyeongnam area (near-Chinju) was studied to evaluate the environmental risk factors, physical examinations and 4 disease entities(abomasal displacement, traumatic reticulopericarditis ＆ -peritonitis, milk fever and lameness) in 40(34 in second year)dairy herds (total 1253 dairy cattle). In feeding environments, we examined housing system, forage percentage in ration, stall types, playground, cleanness of stall. In housing system, most of herds (60%) have tie-stall types and 36 herds are open-type housing. The forage ratio of ration was less than 50% in most of herds (67%). 39 herds had their own playgrounds and the frequency of playground cleanness was irregular, Physical examinations included the T(temperature), P (pulse), R (respiration), abnormalities of superficial lymph nodes, claw examination and total CBC with blood from tail veins. T, P, R are within normal limits (T : 38.1$\pm$0.6$^{\circ}C$, P : 84.6$\pm$12.9/min., R : 24.0$\pm$7.6/min. ,respectively), the swelling of lymph nodes were shown in 13 cattle and overall claw trimming was required in 3 herds. In blood examination, 23 cattle showed leuko-cytosis and 7 cattle showed low RBC and hemoglobin level, the other cattle were within normal limits (WBC : 8.90$\pm$2.06 10$^3$/ul., RBC : 6.36$\pm$1.02 10$^{6}$ ul, Hb : 9.83$\pm$ 1.20 g/dl PCV : 27.43$\pm$5.67 %, respectively). In 4 disease entities, we found some metallic foreign bodies in men of 13 cattle, which had predisposing factors of traumatic reticulopericarditis and reticuloperitonitis, 13 abomasal displacement, 51 milk fever and lameness in 39 cattle.

• 대한치과교정학회지
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• 제23권1호
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• pp.17-35
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• 1993

We tried to evaluate frequencies and severities of malocclusion of various socioeconomic areas according to growth and development. To obtain objective validity, we used Handicapping Labiolingual Deviation (HLD) suggested by Draker, Treatment Priority Index (TPI) by Grainger, Handicapped Malocclusion Assessing Record (HMAR) by American Dental Association and American Association of Orthodontist. Seoul and Kwangju were selected as an urban group, Ahnyang as an middle socioeconomic group and Hwasun near the Kwangju area as an rural group. 140 (male 63, female 73) of 5th grade in 'E' elementary school students in Seoul, 202 (male 101, female 101) of 'S' elementary school students in Kwangju, 207(male 105, female 102) of 'H' elementary school students in Hwasun, and 100(male 49, female 51) of 'M' elementary school students of in Ahnyang of all the same grade were analyzed and we obtained the results as follows; 1. TPI, HLD, and HMAR showed high coincidence and reproducibility between different observer. (p<0.01) 2. In comparison of TPI, HLD, and HMAR according to clinical decision, there was statistically difference between each other. (p<0.01) 3. As the severity of malocclusion increases there was high correlation between TPI and HLD, and between HLD and HMAR (p<0.05) 4. With respect to differences between areas in TPI and HLD, there was statistically difference between Ahnyang and other areas. 5. In Seoul as an urban group there was a high incidence of periodic checkup and history of orthodontic treatment than other area. 6. Mode of feeding and posture during sleeping did not affect the severity of malocclusion. As a conclusion, TPI, HLD and HMAR are so reproducible and coincident that they can be used as a guide on evaluating the frequency and severity of malocclusion and determining the priority of orthodontic treatment to determine the need and supply of orthodontic treatment. Furthermore these indices can provide objectively valid data for establishing public health problem solution.