• 해양환경안전학회지
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• 제20권3호
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• pp.296-303
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• 2014

The Axiom propeller is a unique 3 bladed propeller and it enables to generate the same amount of thrust going ahead as it does going astern because of its 's' type skew-symmetric blade section. A earlier variant of the design (Axiom I propeller) performed a low propeller efficiency, maximum 35 % efficiency, and further blade outline design was carried out to achieve a higher efficiency. The optimized new blade outline (Axiom II propeller) has more conventional Kaplan geometry shape than Axiom I propeller. Model tests of open water performance and propeller cavitation for both propellers were conducted at Emerson Cavitation Tunnel in order to compare their performances. Experiment results revealed that Axiom II propeller provides a maximum 53 % efficiency and provides better efficiency and cavitation performance over the Axiom I propeller under similar conditions.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2012년 춘계학술대회
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• pp.579-583
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• 2012

The Design of Experiment (DOE) is a most practical technique when establishing an optimal condition for production technology in Six Sigma innovation project. This research proposes the assessment of properties of error terms, such as normality, equal variance, unbiasedness and independence. The properties of six nonparametric ranking techniques for checking normality assumption are discussed as well as run test which is used to identify the randomness, and to check unbiased assumption. Furthermore, Durbin-Watson (DW) statistics and ARIMA (p,d,q) process are discussed to identify the serial correlation.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.203-209
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• 2004

Virtual Reality(VR) is a new technology which makes humans communicate with computer. It allows the user to see, hear, feel and interact in a three-dimensional virtual world created graphically. In this paper, we introduced VR into psychotherapy area and developed VR system for the exposure therapy of acrophobia. Acrophobia is an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used as a treatment. Lately the virtual reality technology has been applied to that kind of anxiety disorders. A virtual environment provides patient with stimuli which arouses phobia, and exposing to that environment makes him having ability to over come the fear. In this study, the elevator stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a feel of phobia and without phobia, heart rate was measured during experiment. And also measured a person's HR after the virtual reality training. In this study, we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.110-111
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• 2013

This research studies in the field of domestic fires are an issue in many scientific fire research as a research method to validate the domestic environment and ISO-9705 housing on the basis of experiments in virtual space by making a single fire compartment space for conducting experiments and Appearance of a fire occurring within each flammable Heat Release Rate analysis was carried out mainly. Placed within the space of one flammable HRR calculated as the sum of the number of single-room fire experiments conducted and the results compared with the value in comparing the conduct of fire locations and fire load within the building area of the future, the HRR value represents the change in domestic a consideration of the safety of the building is to propose matters.

• 한국안전학회지
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• 제12권2호
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• pp.37-44
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• 1997

Composite materials have various complicated characteristics depending on the ply materials, ply orientations, ply stacking sequences and boundary conditions. Therefore, it is difficult to analyze composite materials. For efficient use of composite materials in engineering applications, the dynamic behavior such as natural frequencies and nodal patterns should be identified. This study presents FEM results for the free vibration of symmetrically and antisymmetrically laminated composite and hybrid composite rectangular plates. The natural frequencies of laminated composite rectangular plates having the various boundary conditions (completely clamped, 2-edge clamped, cantilevered) are experimentally obtained. In order to demonstrate the validity of the experiment, FEM analysis using ANSYS was performed and natural frequencies experimentally obtained is compared with that calculated by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.

• 한국안전학회지
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• 제15권3호
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• pp.45-51
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• 2000

This paper studies the effect of vibrational characteristics of the various tubes analyzed though experiment. By an experiment analysis we found out that the factor of system vibration is fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through three experiments. Three experiments are modal test on each tube, FRF in continuous system, and vibrating tests when the system is driving on. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than wave induced vibrations. and according to the variation of configuration, the frequencies are different each other. And we found that though fluid passed away through the tube, the tendency of system vibration level was similar with the mode shape at the simple system.

• 대한안전경영과학회지
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• 제18권4호
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• pp.131-137
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• 2016

In unlimited competition era changed rapidly, productivity improvement and raw cost reduction by working improvement are very important for the survival of middle and small-sized companies. At this moment, middle and small-sized companies are cleary important in domestic industry. Therefore, this researcher applied TPS(Toyota production system) 7 wastes by experiment planning method for wastes of lots of working processes at the manufacturing site of automobile assembly manufacturing company, D company, analyzed current system of D company applied so as to verify if value creation works and factors were minimized during the production and drew results by analyzing experimental planning for analyzing waste elimination.

• 대한안전경영과학회지
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• 제23권4호
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• pp.43-48
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• 2021

In this study, the experiment was conducted on a fire door(W × H = 0.98 m × 2.19 m) installed on the vestibule. The effective leakage area for each opening angles and closing forces derived from the impulse-momentum equation was compared and analyzed with the experimental results. As a result of the experiment, the major factors affecting the door closing forces were the pressure difference and the area of the door. The difference of door closing forces between measured and calculated values by the impulse-momentum equation showed a deviation of less than ±15% at the opening angles of 5°to 10°. At the door opening angle of 2.5°, the dynamic pressure was much higher than the measured static pressure, and this pressure difference is estimated to be air resistance acting to prevent the door from being completely closed.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1555-1562
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• 2023

Natural circulation phenomena have been nowadays largely revisited aiming to investigate the performances of passive safety systems in carrying-out heat removal under accidental conditions. For this purpose, assessment studies using CFD (Computational Fluid Dynamics) and also 3D thermal-hydraulic system codes are considered at different levels of the design and safety demonstration issues. However, these tools have not being extensively validated for specific natural circulation flow regimes involving flow mixing, temperature stratification, flow recirculation and instabilities. In the present study, an experimental test case based on a small-scale pool test rig experiment performed by Korea Atomic Energy Research Institute, is considered for code-to-code and code-to-experimental data comparison. The test simulation is carried out using the FLUENT and the 3D thermal-hydraulic system CATHARE-2 codes. The objective is to evaluate and compare their prediction capabilities with respect to the test conditions of the experiment. It was observed that, notwithstanding their numerical and modelling differences, similar agreement results are obtained. Nevertheless, additional investigations efforts are still needed for a better representation of the considered phenomena.

• 한국안전학회지
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• 제32권6호
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• pp.9-15
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• 2017

Recently many researches were conducted on the interlaminar fracture that is a delamination between laminates by using ASTM standardized methods. However the experiment of the intralaminar a fracture is difficulty. In this study, four types of CFRP/GFRP composites with different layer structures were compared to evaluate an intralaminar fracture toughness under the mode I. Also the CNTs were added to the layer for the examination of the fracture toughness improvement. And the characteristics of the crack propagation behaviour was observed using a microscope. The obtained results can be useful for the evaluation of the intralaminar fracture toughness of the CNT reinforced CFRP/GFRP composites.