• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• 공학교육연구
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• 제24권2호
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• pp.20-28
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• 2021

In 2020, the COVID-19 pandemic has brought dramatic changes in the field of engineering education. Contrary to the traditional engineering education emphasis on content-oriented, design-based, hands-on, experimental, and field experience, most of engineering classes in 2020 had to be undertaken remotely online. However, it has not been explored how professors and students perceive about such a shift in engineering education. The aim of the current study was to investigate the perceptions of professors and students on online classes in engineering colleges during spring Semester 2020. Questionnaire data were collected from 100 professors and 4,152 students in the college of engineering. The results of this study were as following: Students were less satisfied with the online classes than professors. The online lecture method that students were most satisfied with was the recorded lecture. This is likely due to the fact that the recorded lectures can be repeated multiple times anytime, anywhere. Moreover, the experimental classes, which conventionally has more of an emphasis on the hands-on experience, also had to be conducted remotely, showing even lower satisfaction among students. Most of professors reported that the average hours they spent on preparing for online lecture increased compared to face-to-face class. Both professors and students preferred in-person exam as a desirable method of end-of-semester assessment for grading. The results of the current study have important implications for the improvement of online course environments. It is important for professors to design a structured class suitable for online education and understand the challenges students encounter during online classes. Also, professors should communicate more openly about their expectations and rubrics for class goals and assignments. Schools also needs to make effort to provide the support for the internet environment of students.

• Composites Research
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• 제21권3호
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• pp.24-30
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• 2008

건설분야에서 사용하고 있는 건설재료인 콘크리트는 대부분 외기에 직접 노출되어 있기 때문에 유해환경으로부터 열화되어 내구성이 저하될 수 있다. 특히, 교량의 교각 및 말뚝과 같은 부재들은 수분의 침투, 동결융해 등의 영향으로 내구성의 감소정도가 심각할 수 있다. 최근 이러한 문제점을 보완하고 효율적인 부재를 제작하기 위해 토목분야에서는 CFFT(Concrete Filled FRP Tube)가 제안되어 연구되고 있다. CFFT는 효율적으로 콘크리트를 구속하여 압축성능을 향상시키고, 화학적 저항성이 우수한 FRP가 외부에 노출되어 반영구적으로 사용될 수 있으며, 연성, 에너지 흡수능력 등을 향상시키는 것으로 평가되고 있다. 그러나 CFFT에 대한 설계규준이 마련되어 있지 않고, FRP-콘크리트 합성부재에 대한 구조거동이 불확실하여 현장에 적용하기 위해서는 다양한 연구가 선행되어야 한다. 이 연구에서는 CFFT에 대한 압축실험을 통해 구조적 거동을 조사하였으며, 실험결과와 기존 연구결과를 비교 분석하여 극한압축강도 및 변형률을 예측할 수 있는 식을 제안하였다. 또한, CFFT의 압축실험에서 고려되어야 할 사항들에 대해 간략히 설명하였다.

• 한국간호교육학회지
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• 제20권2호
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• pp.266-275
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• 2014

Purpose: The purpose of this study was to identify the effects of the education program to promote self care for elderly patients with percutaneous coronary intervention. Method: The research was a quasi-experimental study using a nonequivalent control group non-synchronized design. The participants was 56 patients, 28 in the experimental group and 28 in the control group. A pretest and a posttest were conducted to measure main variables. The self care education program, consisting of flash animation, leaflet and telephone counseling, was given for the experimental group. Data were analyzed using ${\chi}^2$, Fisher's exact test, and independent t-test with SAS statistics program. Results: There were statistically significant increase in knowledge and self care behavior, and decrease in anxiety by difference between a pretest and a posttest in the experimental group compared to that in the control group. Conclusion: The result of this study indicate that the self care education program is effective in increasing knowledge and self care behavior, and in decreasing anxiety for elderly patients with percutaneous coronary intervention. Therefore, it can be usefully utilized in the field of nursing for elderly patients with percutaneous coronary intervention.

• 한국의류학회지
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• 제28권11호
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• pp.1384-1394
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• 2004

The purposes of this study were to investigate the current performance of 119 rescue uniforms and to improve them in terms of fitness, mobility, functionality, and convenience. This study was conducted a questionnaire survey on rescuers in 22 rescue squads in Seoul through direct. observations and face-to-face interviews to investigate the dissatisfaction of their uniforms. According to the results of this survey, respondents were highly dissatisfied with the fitness of uniforms, design, and functionality. liking into consideration of the problems found through this survey, an experimental uniform was developed as follows. The girth and width of the experimental uniform were designed to be more ample than the current uniforms and the jacket could be worn over pants. And the size and the number of pockets were increased in both the Jacket and trousers. In addition, the hems of the sleeves and trousers as well as the fly front of the jacket were improved. Furthermore, darts were added to the front and back of the knees to improve knee movement. Then an experimental uniform was evaluated through three sequences of wearing tests to compare it with the current uniforms: the evaluation of the appearance, mobility. and performance at field activity. According to these tests, the experimental uniform was found to be more satisfactory than former one.

• 대한간호학회지
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• 제42권2호
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• pp.258-268
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• 2012

Purpose: The purpose of this study was to identify the effects of the program to promote self management for patients with chronic hepatitis B. Methods: The research was a quasi-experimental design using a non-equivalent control group pre-post test. The participants were 61 patients, 29 in the experimental group and 32 in the control group. A pretest and 2 posttests were conducted to measure main variables. For the experimental group, the self-management program, consisting of counseling- centered activities in small groups, was given for 6 weeks. Data were analyzed using $X^2$, t-test, and repeated measures ANOVA with PASW statistics program. Results: There were statistically significant increases in knowledge, self-efficacy, active ways of coping, and self-management compliance but not in passive ways of coping in the experimental group compared to the control group over two different times. Conclusion: The results of this study indicate that the self-management program is effective in increasing knowledge, self-efficacy, active ways of coping, and self-management compliance among patients with chronic hepatitis B. Therefore, it can be usefully utilized in the field of nursing for patients with chronic disease as a nursing intervention for people with chronic hepatitis B.

• 대한간호학회지
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• 제39권1호
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• pp.10-20
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• 2009

Purpose: The purpose of this study was to identify the effects of hand acupuncture therapy on pain, ROM, ADL, and depression among older people with low back pain and knee joint pain. Methods: The research was a quasi-experimental design using a non-equivalent control group pre-post test. The participants were 40 patients, 18 in the experimental group and 22 in the control group. A pretest and 2 posttest were conducted to measure the main variables. For the experimental group, hand acupuncture therapy, consisting of hand acupuncture and press-pellets based on corresponding points, was given. Results: There were statistically significant differences in pain, ROM in knee joint, and ADL in the experimental group but not in depression compared to the control group over two different times. Conclusion: The hand acupuncture therapy was effective for low back pain, knee joint pain, ROM in knee joint and ADL among the elders in this study. Therefore, the hand acupuncture therapy can be utilized in the field of geriatric nursing as a nursing intervention for older people with low back pain and knee joint pain.

• Tribology and Lubricants
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• 제31권4호
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• pp.141-147
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• 2015

Gas foil thrust bearings (GFTBs) have attractive advantages over rolling element bearings and oil film thrust bearings, such as oil-free operation, high speed stability, and high-temperature operation. However, GFTBs have lower load carrying capacity than the other two types of bearings owing to the inherent low gas viscosity. The load carrying capacity of GFTBs depends mainly on the compliance of the foil structure and the formed hydrodynamic wedge, where the gas pressure field is generated between the top foil and the thrust runner. The load carrying capacity of the GFTBs is very important for the suitable design of oil-free turbomachinery with high performance. The aim of the present study is to identify the characteristics of the load carrying performance of GFTBs. A new test rig for the experimental measurements is designed to provide static loads up to 800 N using a pneumatic cylinder. The maximum operating speed of the driving motor is 30,000 rpm. A series of experimental tests—lift-off test, static load performance test, and maximum load capacity test—estimate the performance of a six-pad GFTB, in terms of the static load, driving torque, and temperature. The maximum load capacity is determined by increasing the static load until the driving torque rises suddenly with a sharp peak. The test results show that the torque and temperature increase linearly with the static load. The estimated maximum load capacity per unit area is approximately 80.5 kPa at a rotor speed of 25,000 rpm. The test results can be used as a design guideline for GFTBs for realizing oil-free turbomachinery.

• 한국가시화정보학회지
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• 제9권4호
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• pp.54-62
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• 2011

KAERI has developed a KALIMER-600 which is a pool-type sodium-cooled fast reactor with a 600MWe electric generation capacity. For a SFR development, one of the main topics is an enhancement of the reactor system safety. Therefore, we have a long-term plan to design the large sodium experimental facility to evaluate the reactor safety and component performance. In order to extrapolate a thermal hydraulic phenomena in a large sodium reactor, the thermal hydraulics phenomena is under investigation in a 1/$10^{th}$ water-simulant facility for the KALIMER-600. In this paper, we shortly described the experimental facility setup and the measurement of the isothermal global flow behavior. For the flow field measurement, the PIV method was used in a transparent Plexiglas reactor vessel model at around $20^{\circ}C$ water condition.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.29-36
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• 2004

The paper describes recent experimental results on the development of Digital Magnetic Compass (DMC), which can provide smart automatic correction functions to the magnetic interferences. The design methodology of magnetic sensing circuit with ring-core fluxgate sensor is represented. The performance results of the sensing circuits are discussed with error analysis by polynomial regressions. As test results, the sensing circuit filtered only the second harmonic signal that is proportional to the direction of earth's magnetic field, and it leads to the obtainment of bearing information. In addition, the total residual errors of DMC can be analyzed by the adoption of polynomial regressions. It shown that the possibility of high precise DMC, in the future.