• Journal of Nutrition and Health
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• 제34권8호
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• pp.946-955
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• 2001

This study was performed to investigate the dietary supplement use and related factors by college students attending in web class. One thousand four hundred college students(male: 632, female: 768) were participated in this study. The questionnaire about dietary supplements use, demographic characteristics, eating behavior, health-related lifestyles, nutrient intake was self-administered and the data were obtained via internet or mail. Dietary supplements were taken by 63.6%(male : 62.2%, female : 64.2%) of subjects. The higher concern about nutrition and health, the higher the incidence of dietary supplements taking was(p < 0.05). Dietary supplement users were satisfied more than non-users about meal served(p < 0.05). Supplements used by most male students were lactic acid beverage, Chinese medicine, geigogi geisoju and multivitamin, Chinese medicine, fiber-processed flood for female students. Most of dietary supplement users answered that the sources of information on supplements were 'friend, family or relatives' and 'TV or radio'. Dietary supplement users were taking significantly more nutrients compared to non-use. Therefore, it may be necessary to provide nutrition information and education which show that balanced diet is the best nutritional strategy for health promotion and diet supplements can be helpful in deficient state nutrients.

• 동아시아식생활학회지
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• 제12권4호
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• pp.299-306
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• 2002

This study was undertaken to compare the obesity related dietary factors among rural middle school students living in the Daegu.Kyungbuk area. Anthropometric data showed that mean height and weight were 162.7$\pm$8.6cm and 53.9$\pm$9.8kg in 220 male students and 158.4$\pm$6.2cm and 51.0$\pm$7.6kg in 210 female student. Mean BMIs for boys and girls were 19.00$\pm$2.35 and 19.30$\pm$2.45, respectively. 71.36% of male students and 71.9% of female students were underweight by the BMI index. Students who skipped the breakfast were up to 66.8%. The reasons for skipping a meal for both sexes were significantly different. Compared to males, more female respondents felt guilty and depressed related to eating. Furthermore, females were more significantly concerned about body image, diet and body weight (p<0.001), and they were not satisfied with their weight. The sources of information on obesity and diet were radio and TV in males, while females gathered information from magazines and friends. The ideal body weight of male students was heavier than the actual body weight while female students desired a thinner body shape. In conclusion, a different approach for nutrition education based on sex should be developed, and implemented fur adolescents.

• 한국가정과교육학회지
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• 제11권1호
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• pp.1-11
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• 1999

The purpose of this study were to analyze high school girls’sex role identity and underwear purchasing behaviors, and to provide the educational guidelines for high school girls as a underwear comsumer and the fundamental data necessary for the products planning of underwear manufacturing companies. The questionnaire was composed of questions about the types of sex role identity, pursuit factors and purchasing behaviors of underwear. The respondents were girls from 6 high schools in cities in Chonbuk Province. The questionnaires were collected from April 6th to May 12th in 1998. 510 questionnaires were used for data analysis. Frequency, percent, average, standard deviation, F-test, $$\chi$^2$-test, and Duncan’s multiple range test were followed. The results of this study were as follows：1. Among the sex role identity groups, the androgynous group was the largest, and the masculine group was the smallest among high school girls. 2. High school girls sought after practicality most when purchasing underwears, but sought after the brand least. The androgynous group recognized practicality, aesthetics, and sexual attraction most, but the undifferentiated group recognized them least. 3. The high school girls bought underwears objectively when they were worn out, made use of TV, newspaper, and radio advertisements as the information sources, and considered the size, comfort, and style. They recognized the prices of underwears as moderate. They depended on their mother most when purchasing underwears and reflected their dependents opinion on selecting underwears partially. They purchased at the underwear specialty store.

• 한국통신학회논문지
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• 제31권1A호
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• pp.48-57
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• 2006

진행파관 증폭기는 입력되는 RF(radio-frequency)신호를 일정한 크기로 증폭하여 안테나로 출력하는 기능을 수행한다. 본 논문에서는 위성통신용 고출력 SHF(Super High Frequency) 대역 진행파관 증폭기의 캐소드 리플 개선방안을 제안한다. 600W급 SHF대역 진행파관 증폭기의 구현 및 실험을 통하여 제안한 방안이 설계규격을 만족시키는 결과를 얻었다. 또한 RF부로 공급되는 보조전원의 잡음을 저감하여 예측치 못한 잡음성분들을 제거함으로서 RF 성능이 개선되었다. 따라서 본 논문에서 제안한 방안은 매우 효과적이며, 차후 유사장비 개발 시 적용가능 할 것으로 판단된다.

• IEIE Transactions on Smart Processing and Computing
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• 제6권4호
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• pp.299-304
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• 2017

A wireless passive sensor network is a network consisting of sink nodes, sensor nodes, and radio frequency (RF) sources, where an RF source transfers energy to sensor nodes by radiating RF waves, and a sensor node transmits data by consuming the received energy. Against theoretical expectations, a wireless passive sensor network suffers from many practical difficulties: scarcity of energy, non-simultaneity of energy reception and data transmission, and inefficiency in allocating time resources. Perceiving such difficulties, we propose a simple contending-type medium access control (MAC) scheme for many sensor nodes to deliver packets to a sink node. Then, we derive an approximate expression for the network-wide throughput attained by the proposed MAC scheme. Also, we present an approximate expression for the optimal partition, which maximizes the saturated network-wide throughput. Numerical examples confirm that each of the approximate expressions yields a highly precise value for network-wide throughput and finds an exactly optimal partition.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.9-12
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• 1999

This paper presents the development of a control architecture for the autonomous underwater vehicle (AUV) with VARIVEC (variable vector) propeller. Moreover this paper also describes the new technique of controlling the servomotors using the Field Programmable Gate Array (FPGA). The AUVs are being currently used fur various work assignments. For the daily measuring task, conventional AUV are too large and too heavy. A small AUV will be necessary for efficient exploration and investigation of a wide range of a sea. AUVs are in the phase of research and development at present and there are still many problems to be solved such as power resources and underwater data transmission. Further, another important task is to make them smaller and lighter for excellent maneuverability and low power. Our goal is to develop a compact and light AUV having the intelligent capabilities. We employed the VARIVEC propeller system utilizing the radio control helicopter elements, which are swash plate and DC servomotors. The VARIVEC propeller can generate six components including thrust, lateral force and moment by changing periodically the blade angle of the propeller during one revolution. It is possible to reduce the number of propellers, mechanism and hence power sources. Our control tests were carried out in an anechoic tank which suppress the reflecting effects of the wall surface. We tested the developed AUV with required performance. Experimental results indicate the effectiveness of our approach. Control of VARIVEC propeller was realized without any difficulty.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1361-1364
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• 1990

In order to tackle global environmental problems such as destruction of the ozone layer or climatic changes due to atmospheric temperature increase, the acquisition of plentiful and precise data is necessary. Therefore, a means of conducting long-lasting high-resolution measurements over broad areas is required. A feasibility study has been made on a high altitude (20km), super-pressured helium-filled PLTA (Powered Ligher-than-Air) vehicle as an ideal platform for environmental observation. It has a long service life and carries a larger payload than an artificial satellite. This PLTA platform uses an electric propulsion system to maintain position in space against wind currents. The thruster is driven by solar power acquired from solar cells. For night use, solar energy is stored in regenerative fuel cells. This study focuses on energy balance and structural analysis of the hull and platform. The platform is capable of conducting high resolution remote sensing as well as having the capability to serve as a telecommunications relay. The platform could replace a number of ground-based telecommunications relay facilities, guaranteeing sufficient radio frequency intensity to secure good quality telecommunication transmittal. The altitude at which the platform resides has the lowest wind flow in the lower stratosphere, and permits viewing from the ground within a 1,000km range. Because this altitude is much lower than that required of an artificial satellite, the measuring resolution is a couple of thousand times higher than with artificial satellites. The platform can also be used to chase typhoons and observe them from their sources in tropical regions.

• 천문학회지
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• 제40권4호
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• pp.123-125
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• 2007

NGC 1333 is a nearby star forming region, and IRAS 4A and IRAS 4BI are low-mass Class 0 protostars. IRAS 4A is a protobinary system. The NGC 1333 IRAS 4 region was observed in the 22 GHz water maser with a high resolution (0.08") using the Very Large Array. Two groups of masers were detected: one near A2 and the other near BI. Most of the masers associated with A2 are located very close (< 100 AU) to the radio continuum source. They may be associated with the circumstellar disk. Since no maser was detected near AI, the A2 disk is relatively more active than the Al disk. Most of the masers in the BI region are distributed along a straight line, and they are probably related with the outflow. As in many other water maser sources, the IRAS 4 water masers seem to trace selectively either the disk or the outflow. Considering the outflow lifetimes, the disk-outflow dichotomy is probably unrelated with the evolutionary stage of protostars. A possible explanation may be that both the outflow-maser and the disk-maser are rare phenomena and that detecting both kinds of maser around a single protostar may be even rarer.

• 천문학회보
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• 제35권2호
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• pp.59.1-59.1
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• 2010

We have carried out VLBI test observations of the Korean VLBI Network (KVN) at 22/43-GHz in collaboration with Japanese VLBI Exploration of Radio Astrometry (VERA). In order to evaluate the VLBI system of KVN, we have observed several sources using KVN+VERA. They consist of Active Galactic Nuclei (AGNs), which are expected to be compact and to have very well-known structures at spatial resolutions of 50-250 Mega-wavelengths, and Galactic star-forming regions and late-type stars, which have bright H2O and SiO maser emission regions. We have investigated baseline and imaging sensitivities of KVN+VERA. In this talk we report the preliminary results.

• 천문학회보
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• 제35권2호
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• pp.59.2-59.2
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• 2010

We have carried out VLBI test observations of the Korean VLBI Network (KVN) at 22/43-GHz in collaboration with Japanese VLBI Exploration of Radio Astrometry (VERA). In order to evaluate the VLBI system of KVN, we have observed several sources using KVN+VERA. They consist of Active Galactic Nuclei (AGNs), which are expected to be compact and to have very well-known structures at spatial resolutions of 50-250 Mega-wavelengths, and Galactic star-forming regions and late-type stars, which have bright H2O and SiO maser emission regions. We have investigated baseline and imaging sensitivities of KVN+VERA. In this talk we report the preliminary results.