• 대한소아치과학회지
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• 제47권3호
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• pp.293-302
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• 2020

이 연구의 목적은 가상현실 시뮬레이션을 이용한 소아환자 치아우식 진단 경험에 대한 설문조사를 통하여, 임상 실습 전 단계의 치의학 전공 학생들을 대상으로 소아치과적 교육에서의 활용 가능성을 평가하는 것이다. 소아 환자 모델로 유치열기의 5세 여아를 개발하였고, 가상현실 속 진단을 위한 치아 우식 모델을 제작하였다. 치의학 전공 학생들은 15분에 걸친 치아 우식 진단 시뮬레이션을 경험한 뒤, 설문지를 통하여 프로그램 사용 경험을 통한 실재감 및 응용 가능성을 평가하였다. 그 결과, 가상실재감과 외양 평가에서 높은 점수를 얻었다. 또한, 가상현실을 통한 치아 우식 진단 시뮬레이션은 임상 실습 전, 후의 학년, 성별, 가상현실 체험 경험의 유무에 따른 유의미한 차이가 없다는 설문 결과를 얻었다. 이 프로그램을 지속적으로 발전시킨다면, 치의학 교육 분야에 응용 가능성이 높아질 것이다.

• 한국간호교육학회지
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• 제17권2호
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• pp.257-266
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• 2011

Purpose: The aim of this study was to elucidate the themes involved in a nursing experience of caring for extremely low birth weight infants (ELBWIs) in a neonatal intensive care unit (NICU). Methods: Interviews with 6 nurses in various positions and observations in a level III NICU were conducted. The transcribed interview contents and observational notes were reviewed to analyze the data and conceptualize major themes. Results: Three major themes were identified: the fears expressed by the nurses regarding taking care of ELBWIs, reasons for persistent fears, and overcoming fears and gaining intuition. Nurses were afraid of the following factors: the physical fragility of the infants; the possibility of developing disabilities in the future; and the rapid changes in infants' physical condition. These fears were reduced when nurses had developed intuition and confidence in taking care of ELBWIs through various situational experiences. Conclusion: NICU nurses may benefit from obtaining more opportunities to participate in various learning experiences with simulated nursing situations in a variety of patient groups. Applying knowledge and skills into various nursing situations in an integrative way may contribute to enhancing nurses' confidence in nursing practice.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.122-125
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• 2008

Generally, in shipbuilding, large curved block components which have large curvature radius along various directions are used for huge ships such as LPG-vessel and oil tanker ships. Lots of the blocks are manufactured by line heating method which uses a heat source to bend the thick plate materials. The conventional forming process is entirely dependent on the experience of experts because it is done by manual method thus the curvatures and qualities are not uniform even for same part. However, it is hard to adopt the press forming process using die tool sets fur the manufacturing because of the characteristics of the industry that based on the small quantity and variety in the products. In this study, flexible forming technology using numbers of punches is investigated based on the simulation to substitute for the conventional forming method. Thick plate material model was applied to the proposed process to verify the feasibility for hull structure block forming process. The press forming processes were simulated by adopting the explicit-to-implicit sequential solution. Moreover, experiment of the flexible forming process was also conducted and its results were compared with that of simulation.

• Structural Engineering and Mechanics
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• 제30권3호
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• pp.369-382
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• 2008

An oscillator of two lumped masses linked through a vertical spring moves forward in the horizontal direction, initially at a certain height, over a horizontal Euler beam and descends on it due to its own weight. Vibration of the beam and the oscillator is excited at the onset of the ensuing impact. The impact produced by the descending oscillator is assumed to be either perfectly elastic or perfectly plastic. If the impact is perfectly elastic, the oscillator bounces off and hits the beam a number of times as it moves forward in the longitudinal direction of the beam, exchanging its dynamics with that of the beam. If the impact is perfectly plastic, the oscillator (initially) sticks to the beam after its first impact and then may separate and reattach to the beam as it moves along the beam. Further events of separation and reattachment may follow. This interesting and seemingly simple dynamic problem actually displays rather complicated dynamic behaviour and has never been studied in the past. It is found through simulated numerical examples that multiple events of separation and impact can take place for both perfectly elastic impact and perfectly plastic impact (though more of these in the case of perfectly elastic impact) and the dynamic response of the oscillator and the beam looks noisy when there is an event of impact because impact excites higher-frequency components. For the perfectly plastic impact, the oscillator can experience multiple events of consecutive separation from the beam and subsequent reattachment to it.

• 항공우주시스템공학회지
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• 제13권6호
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• pp.36-42
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• 2019

본 논문은 유/무인 항공기 복합운용체계 검증을 위한 시뮬레이션 환경 구축 및 통합 시험에 대하여 다룬다. 유/무인 항공기 지상 시뮬레이션 환경 구축을 위해서 유인기용 시뮬레이터인 X-Plane과 무인기용 시뮬레이터 HILS를 연동하여 상호 복합운영이 가능한지 시뮬레이션으로 검증하였다. 실제 비행시험 전 유/무인 항공기 및 지상통제실 간 C Band 및 UHF 채널을 이용한 통신 가능성을 확인하기 위하여 통신장비를 제작하고 유인 항공기를 이용한 검증을 수행하였다.

• Steel and Composite Structures
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• 제20권4호
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• pp.913-930
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• 2016

It is common practice to use Reduced Web Beam Sections (RWBS) in steel moment resisting frames. Perforation of beam web in these members may cause stress and strain concentration around the opening area and facilitate ductile fracture under cyclic loading. This paper presents a numerical study on the cyclic fracture of these structural components. The considered connections are configured as T-shaped assemblies with beams of elongated circular perforations. The failure of specimens under Ultra Low Cycle Fatigue (ULCF) condition is simulated using Cyclic Void Growth Model (CVGM) which is a micromechanics based fracture model. In each model, CVGM fracture index is calculated based on the stress and strain time histories and then models with different opening configurations are compared based on the calculated fracture index. In addition to the global models, sub-models with refined mesh are used to evaluate fracture index around the beam to column weldment. Modeling techniques are validated using data from previous experiments. Results show that as the perforation size increases, opening corners experience greater fracture index. This is while as the opening size increases the maximum observed fracture index at the connection welds decreases. However, the initiation of fracture at connection welds occurs at lower drift angles compared to opening corners. Finally, a probabilistic framework is applied to CVGM in order to account for the uncertainties existing in the prediction of ductile fracture and results are discussed.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.147-151
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• 2002

Cross flow fan system is widely used for various applications, especially for the air-moving device of heaters, air-conditioners, and air-curtains. Although there are efforts for the optimization of cross-flow fan flow path with different methods of approach, it is still being investigated by many researchers through experimentally and/or theoretically, because the flow pattern of the cross flow fan is not stereotyped. This paper presents some results from numerical experiments for the optimization of the flow path through a cross-flow fan to be applied to indoor wall-mounted room heater. Two dimensional analysis has been applied to a specific fan system including inlet and diffuser outlet. Flow characteristics art presented and discussed for two different flow path at three different operating conditions represented by rotational speed(800, 1,000, 1,200 rpm) of the In. According to the simulated results for the specific fan system under consideration, it could be found that the flow pattern resembles each other at different rotational speed (to say from 800 rpm to 1,200 rpm) for a fixed flow path, while the secondary flows mostly absorbs the speed effects. By changing the flow path significant increase in volume flow rate is estimated upto 2.65 at the same rotational speed. According to the present experience, fan flow path design can be performed more efficiently by incorporating this type of numerical experiments combined with the model tests.

• 한국의류학회지
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• 제39권5호
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• pp.703-713
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• 2015

Consumers' psychological demands for e-tail shopping have increased as websites have become one of the most dominant retail outlets for various fashion products. The lack of realistic social stimuli in virtual contexts (websites) has been a major limitation for many online shoppers. Prior research has focused on the viable role of technology to improve positive social factors in e-tailing; however, this study tests the role of tone in text in fashion e-tail sites on consumers' trust and choice confidence. We conducted a self-administered online survey with 309 individuals from the U.S.. The results indicated positive effects of casual tone in text-based content of a fashion e-tail site on trust and confidence. Trust also has a significant positive effect on confidence. Both trust and confidence improved purchase intention. Given the high price of employing an avatar or simulated salesperson online, using tone in text to increase positive social effect on shoppers can be a positive alternative when managers plan e-tail strategies contributing to consumers' positive shopping experience online. Discussions and study limitations are provided.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.331-336
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• 2005

A lot of manufacturing knowledge and method have applied to increase manufacturing efficiency in industry field. DES(Discrete Event Simulation) is one of solution to deal with manufacturing problems in factory. Beginning of research, old maintenance system of KNR ( Korea National Railroad) and its technical problems are basically investigated. KNR has maintained railway vehicle with their own solution based on experience. Very advanced railway vehicles such as KTX (Korea Train Express) and TTX(Tilting Train Express) will be difficult to maintain with their old maintenance method. In order to apply knowledge of DES, maintenance field of railway must be considered. Imaginary maintenance machine are selected to variable of DES. Maintenance capability of each machine will be evaluated base on imaginary data from imaginary machine. The machine could be very expensive as well as difficult to replace. Target of research is minimization of number of machine in railway workshop. So basic knowledge of discrete event simulation is introduced. Then five essential stages of discrete event simulation are provided. Each maintenance case defined as event. Each event is discrete and simulated base on different case such as one maintenance line with one machine and one maintenance line with two machines in railway workshop. simple maintenance method, discrete event simulation, will be come out very powerful in complicate maintenance system and will be helpful to reduce maintenance cost as well as maintenance labor.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.1-6
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• 2014

PID(Proportional, Integral, Derivative) controller is one of the most used process controllers in nuclear power plants. The optimized parameter setting of process controller contributes to the stable operation and efficiency in the operating nuclear power plants. PID parameter setting is tuned when new process control system is established or process control system is changed. It is a burdensome work for I&C(Instrument and Control) engineers to tune the PID controller because it requires a lot of experience and knowledge. When the plant is in operation, inadequate PID parameter setting can be the cause of the unstable process of the plant. Therefore the results of PID parameter setting should be compared, simulated, verified and finally optimized. The practical PID tuning methods used in process controller are tuning operation calculation(Ziegler-Nicholes, Minimum TIAE, Lambda, IMC), exclusive tuning program based on computer and Matlab application. This paper introduces the various tuning methods and suggests an optimized PID tuning process in the operating nuclear power plants.