• 대한물리의학회지
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• 제10권2호
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• pp.95-98
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• 2015

PURPOSE: This study was conducted to devise a method of preventing water infiltration into the surface electrodes during EMG measurements underwater and on the ground and to check the reliability of Electromyography (EMG) measurements when underwater. METHODS: Six healthy adults were selected as subjects in this study. The measurements in this study were conducted in pool dedicated to underwater exercise and physical therapy room in the hospital building. An MP150 (Biopac Systems, US, 2010) and a BioNomadix 2-channel wireless EMG transmitter (Biopac Systems, US, 2012) was used to examine the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius of dominant side. The subjects repeated circulation tasks on the ground for more than 10 min for enough surface electrode attachment movement. After a 15-min break, subjects performed the circulation task underwater(water depth 1.1m, water temperature $33.5^{\circ}C$, air temperature $27^{\circ}C$), as on the ground, for more than 10 min, and the MVIC of each muscle was measured again. SPSS v20.0 was used for all statistical computations. RESULTS: The maximum voluntary isometric contraction (MVIC) values between the underwater and on the ground measurements showed no significant differences in all four muscles and showed a high intraclass correlation coefficient (ICC) of >0.80. CONCLUSION: We determined that EMG measurements obtained underwater could be used with high reliability, comparable to ground measurements.

• 한국HCI학회논문지
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• 제12권4호
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• pp.27-35
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• 2017

본 연구는 증강현실 게임의 참여와 몰입 사이에 영향을 미치는 매개변인을 규명하는 데 목적이 있다. 참여로부터 형성되는 정서적 애착과 주의집중이 현존감에 대해 나타내는 매개효과와, 현존감이 몰입에 대해 나타내는 매개효과를 통해 참여와 몰입의 관계를 알아보았다. 연구가설의 검증을 위해 포켓몬 고 게임이용자를 대상으로 온라인 설문을 실시하였다. 증강현실몰입(Augmented Reality Immersion) 설문척도를 번역한 설문조사를 통해 총 200부의 설문응답을 수집하여 분석에 사용하였다. 분석에는 SPSS 23.0과 Mplus 7.0 프로그램을 사용하여 문항내적합치도 (Cronbach's ${\alpha}$) 계수를 통해 척도의 신뢰도를 확인하고 정규분포 충족 여부에 의해 모형 적합도를 확인한 후, 경로분석을 실시하여 각 변인 간 인과관계와 매개효과를 확인하였다. 연구결과, 참여와 몰입의 관계에서는 직접적 인과관계를 보이지 않았으나 증강현실 게임 참여가 현존감과 몰입에 도달하는 과정에서 정서적 애착과 주의집중이 매개가 되었을 때 인과관계가 뚜렷하게 나타났다. 결론적으로, 증강현실 게임의 참여에서 몰입으로 향하는 과정에 참여자의 정서적 애착과 주의 집중 상태가 주요한 요인으로 작용함을 체계적으로 설명함으로써 인간과 상호작용하는 증강현실 기술의 발전에 있어서 고려해야 할 요소를 밝혀낸 점에 본 연구의 의의가 있다.

• 지역사회간호학회지
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• 제21권4호
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• pp.458-467
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• 2010

Purpose: This study was conducted in order to identify factors related to the health behavior in elementary school children at a late school age and to provide basic data to develop more concrete and practical applications for health promotion and disease prevention. Methods: The participants were 2,775 4th, 5th and 6th graders sampled from 10 elementary schools in Busan Metropolitan City and data were collected from 15th May to 30th June, 2010. The collected data were analyzed by mean, percentile, t-test, ANOVA, Pearson s correlation coefficient, and stepwise multiple regression using the SPSS/WIN 17.0 program. Results: The average percentiles for self-rated health, body satisfaction, stress, parent attachment, self-esteem, and health behavior were 82.8, 69.5, 40.9 79.3, 75.9 and 75.9, respectively. There was significant relationship among the levels of self-rated health, body satisfaction, stress, parent attachment, self-esteem, and health behavior. Body satisfaction was the most powerful factor to the health behavior of elementary school children at a late school age, and was followed by parent attachment, self-rated health, self-esteem, and grade in order. These variables explained 26.6% of the total variance in health behavior. Conclusion: Health promotion behavior programs including body satisfaction and self-esteem elevation programs should be applied to children at home and in school and community. To achieve this, institutional and economic support should be continued.

• 한국해양학회지:바다
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• 제3권4호
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• pp.249-260
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• 1998

해수에 잠긴 인공기질 표면에서 미세조류의 부착과 후속적으로 나타나는 성장과정을 이해하기 위해 규조류의 부착과 주변수의 종 급원(species pool)과의 관계를 조사하였다. 1995년 7월부터 1997년 2월까지 인천항 내에서 아크릴 슬라이드를 이용하여 규조류의 부착에 관해 연구하였고, 주변 해수를 조사하였다. 또한 생물막 초기형성 과정에서 노출시간의 증가에 따라 나타나는 부착미세조류 군집의 종조성과 수도의 변화를 유리, 아크릴, 티타늄, 구리 및 생물오손방지 페인트로 도포된 슬라이드 등 다양한 인공기질 표면을 이용하여 조사하였다. 아크릴 슬라이드에서 규조류의 이입률은 주변수의 저서규조류의 수도변화와 유의성 있는 상관관계를 나타냈으며 ($r^2$=0.78, p<0.01, n=42), 이는 주변수의 저서규조류의 수도에 의해 영향을 받는 것을 지시한다. 아크릴 슬라이드에서 봄철에 단배선 형태 규조류의 부착능력(이입계수)이 복배선 형태에 비해 5 배 높게 나타났다. 그러나 부착점유율은 단배선 형태가 복배선 형태에 비해 3 배 낮게 나타났다. 겨울철에는 중심형 규조류의 부착능력이 다른 형태들에 비해 높게 나타났고 부착점유율도 높게 나타났다. 이는 규조류의 부착이 주변해수에 출현한 저서 규조류의 수도 및 부착능력에 의한 결과임을 지시한다. 우상형 규조류가 연구기간동안 모든 인공기질 표면에 대부분 부착 출현하였고, 겨울철에는 중심형 규조류가 모든 인공기질 표면에 우정 부착하였다. 생물오손방지 페인트로 처리된 표면에서는 독성에 대한 내성이 강한 것으로 판단되는 Hantzschia virgata, Licmophora abbreviata, Melosira nummuloides가 우점하여 부착하였다. 노출시간이 증가함에 따라 부착규조류의 수도는 유리, 티타늄, 아크릴 슬라이드에서 지수적으로 증가하였고, 최대수도는 유리 ${\geq}$ 아크릴 > 티타늄 > 구리 ${\geq}$ 페인트처리 슬라이드의 순으로 높게 나타났다. 모든 인공기질 표면에서 부착규조류의 성장률은 $2{\sim}3^{\circ}C$에서 보다 $24{\sim}25^{\circ}C$의 수온에서 높게 나타났고, 유리 슬라이드에서 다른 표면에 비해 전반적으로 높은 값을 보였다. 해수 중에서 노출시간의 증가에 따라 관찰된 우점종은 납작한 형태인 Amphora coffeaeformis, 부채꼴 형태인 Synedra tabulata, stalk 형태인 Licmophora paradoxa 그리고 사슬형태인 M. nummuloides로 나타났고, 부착미세조류 군집에서 미소천이(micro-succession)가 관찰되었다. 이러한 우점종 조성은 미세조류 생물막이 발달하여 서식공간이 제한됨에 따라 나타난 종 적응의 결과로 보인다.

• 문화기술의 융합
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• 제6권2호
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• pp.223-230
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• 2020

본 연구는 간호대학생을 대상으로 자아탄력성, 성인애착, 대인관계유능성이 학업스트레스에 미치는 영향을 확인하여 학업스트레스를 조절하기 위한 기초자료를 제공하고자 시도되었다. 연구참여자는 B와 Y시의 간호대학생 287명을 대상으로 하였다. 자료분석은 SPSS 22.0 프로그램을 이용하여 실수, 백분율, 평균, 표준편차, t-test, ANOVA, 피어슨 상관계수, 다중회귀분석으로 분석하였다. 대상자의 학업스트레스는 2.28±.46점이었고, 일반적 특성에 따른 학업스트레스의 차이를 분석한 결과 학년(F=16.342, p<.001), 경제상태(F=3.331, p=.037), 음주 횟수(F=3.393, p=.035), 학과만족도(F=40.539, p<.001), 대학생활만족도(F=67.304, p<.001)에서 유의한 차이를 나타냈다. 연구대상자의 학업스트레스는 성인애착(r=.557, p<.001)과는 정적상관관계, 자아탄력성(r=-.379, p<.001), 대인관계유능성(r=-.423, p<.001)과는 부적상관관계를 나타냈다. 학업스트레스에 영향을 미치는 요인은 자아탄력성, 성인애착으로 나타났고, 설명력은 34%로 확인되었다. 본 연구결과를 통하여 간호대학생을 대상으로 학업스트레스에 영향을 미치는 요인을 확인하기 위한 반복연구가 필요하다.

• 한국생산제조학회지
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• 제21권4호
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• pp.601-607
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• 2012

The magnetic abrasive polishing (MAP), for online monitoring with AE sensor attachment, was performed in this study. To predict the surface roughness after the magnetic abrasive polishing of NAK80, the signal data acquired from the AE sensor were analyzed. A dimensionless coefficient, which consisted of average of AErms and standard deviation of AE signal, was defined as a characteristic of the MAP and a prediction model was obtained using least square method. A neural network, which had multiple input parameters from AE signals and polishing conditions, was applied for predicting the surface roughness. As a result of this study, it was seen that there was very close correlation between the AE signal and the surface roughness in the MAP. And then on-line prediction of the surface roughness after the MAP of the NAK80 was possible by the developed prediction model.

• 대한조선학회논문집
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• 제51권2호
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• pp.154-161
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• 2014

Naval ships have hull appendages which are more exposed to the outside because of its small block coefficient compared with commercial ships. These exposed hull appendages like skeg, strut and shaft line affect the maneuverability of a ship. The effect of hull appendages has considered at initial design stage to estimate more accurate maneuverability. In this paper, sensitivity analysis is used to analyze the effect on maneuverability by hull appendages. 3 DOF maneuvering equations based on Mathematical Modelling Group (MMG) model are used and propeller & rudder model are modified to reflect the characteristics of twin propeller & twin rudder. Numerical maneuvering simulations (Turning test, Zig-zag test) for benchmark naval vessel, David Taylor Model Basin (DTMB) 5415 are performed. In every simulation, it is calculated that stability indices and maneuverability characteristics (Tactical Dia., Advance, 1st Overshoot, Time of complete cycle) with respect to the parameters (area times lift coefficient slope, attachment location) of hull appendages. As a result, two regression formulas are established. One is the relation of maneuverability characteristics and stability indices and the other is the relation of stability indices and hull appendages.

• 전기학회논문지P
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• 제56권1호
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• pp.1-5
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• 2007

Study on the electron transport coefficient in mixtures of CF4 and Ar, have been analyzed over a range of the reduced electric field strength between 0.1 and 350[Td] by the two-term approximation of the Boltzmann equation (BEq.) method and the Monte Carlo simulation (MCS). The calculations of electron swarm parameters require the knowledge of several collision cross-sections of electron beam. Thus, published momentum transfer, ionization, vibration, attachment, electronic excitation, and dissociation cross-sections of electrons for $CF_4$ and Ar, were used. The differences of the transport coefficients of electrons in $CF_4$ mixtures of Ar, have been explained by the deduced energy distribution functions for electrons and the complete collision cross-sections for electrons. The results of the Boltzmann equation and the Monte Carlo simulation have been compared with the data presented by several workers. The deduced transport coefficients for electrons agree reasonably well with the experimental and simulation data obtained by Nakamura and Hayashi. The energy distribution function of electrons in $CF_4-Ar$ mixtures shows the Maxwellian distribution for energy. That is, $f({\varepsilon})$ has the symmetrical shape whose axis of symmetry is a most probably energy. The proposed theoretical simulation techniques in this work will be useful to predict the fundamental process of charged particles and the breakdown properties of gas mixtures. A two-term approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 학술대회 논문집 전문대학교육위원
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• pp.159-162
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• 2006

In this paper energy distribution function in $SiH_4$ has been analysed over the E/N range 0.5${\sim}$300Td and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with theoretical for a rang of E/N values.

• 설비공학논문집
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• 제8권2호
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• pp.230-239
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• 1996

A multi-faceted experimental investigation has been carried out to study the cooling performance for stacked modules in arrays of heat generating rectangular modules deployed along PCB's in the enclosed cabinet. The main parameters which have an important effect on cooling characteristics are flow velocity, channel spacing, installation of fan unit, attachment of heat sink, and acoustic noise. The results of individual effect are very helpful for the electronic packaging designer. In order to improve the cooling performance, it is certain that the enlargement of channel space is obviously effective, while this id disadvantageous in high density electronic packaging. Each of the paameters is quantitatively examined as cooling performance and the correlation of Reynolds number to Nusselt number is compared with previous study.