• 한국안전학회지
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• 제15권2호
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• pp.46-50
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• 2000

A theoretical model for the evaluation of small surface fatigue crack initiated from a pit-type surface flaw is presented. The low frequency scattering model is developed based on the reciprocity principle for the elastic wave scattering. The effect of the flaw on the surface wave reflection from the crack is taken into account approximately by means of the stress intensity factor of cracks on a through thickness hole. The reflection coefficient of surface wave is derived for the prediction of small surface crack depth. Calculated results for pits with different sizes are illustrated.

• 한국안전학회지
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• 제26권2호
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• pp.20-25
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments. The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a multi-core cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the characteristic of cable fire is investigated and the heat-flux evaluation for cable fire is studied. Moreover, a diagnostic methodology for degraded cable in nuclear power plants is presented.

• 수산해양기술연구
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• 제39권1호
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• pp.1-7
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• 2003

When a ship is course-keeping in the open seas, autopilot system is adapted. The design of autopilot system is very important for improvement of ship′s element research. Automatic steering system consists of autopilot device, power unit, steering gear, magnetic or gyro compass and ship dynamics. In order to evaluate automatic steering system of ships in open seas. we need to know the characteristics of each component of the system, and also to know the characteristics of disturbance to ship dynamics. In this paper, I provide evaluation method of autopilot navigation system of the fishing ship. Prediction method based on the principle of linear superposition is introduced for irregular disturbance. For the evaluation of automatic steering system of a ship, "performance index" is introduced from the viewpoint of energy saving and calculation method is frequency response analysis. Finally, I carried out calculation of sensitivity of control constants of autopilot with various conditions of ocean environments.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.324-327
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• 2005

We propose a novel technique for evaluating the azimuthal anchoring strength of the alignment film on the nematic liquid crystal (LC). In our evaluation, a unique cell, which has two domain in one cell, was used; one is hybrid aligned nematic (HAN) region, the other is twsited nematic (TN) region (viz. HAN/TN two domain cell). From the comparison of director angles on the front substrate with each region, we are able to determine the angle between easy axis and real director axis on the front substrate. From this evaluation, the azimuthal anchoring strength was obtained accurately.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2079-2081
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• 2005

Electrical treeing occurrence is caused by some defect in solid insulator. Those are accompany the PD(partial discharge) occurrence. And lifetime of the insulator is affected by PD. So, detection of electrical treeing is important thing as this view. Especially, detection of the end treeing is more important and have meaning for industrial engineering because concerned with maintenance and replacement of equipment. In this paper, evaluation of treeing process were studied and PCA(principle component analysis)-LDA(linear discriminant analysis) as classification method were used. The result is present the good recognition.

• Journal of Magnetics
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• 제17권3호
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• pp.206-209
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• 2012

Peak interval for reversible permeability is presented for nondestructively evaluating the remanent life of 1Cr-0.5Mo steel. The method to measure the peak interval of reversible permeability is based on the value of reversible permeability is the same as the differential value of the hysteresis loop. The measurement principle is based on the first harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to a frequency of the exciting voltage. Results obtained for the peak interval of reversible permeability and Rockwell hardness on the aged samples decrease as aging time and the Larson-Miller parameter increase. We could estimate the remanent life of 1Cr-0.5Mo steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, nondestructively.

• 한국실내디자인학회논문집
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• 제20권1호
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• pp.208-219
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• 2011

This study is intended to formulate the issues through the status analysis and image evaluation for each street on the basis of colors for the outdoor advertisements for part of street side in the oldest downtown for its construction year. Analysing the business type of the street side, it displays the identity of the fashion business area and the color status shown on the outdoor advertisement did not consider the harmony on the other business type and building improvements that it displays chaotic street views in overall. Status of color for the outdoor advertisement compared and analyzed for each street-side to be analyzed with high color contrast with the building structure and outdoor advertisements than the Street B side where there are many businesses of fashion sundries and fashion clothes to form more complicated street scenery visually for the Street A side. The color combination principle of building structure and outdoor advertisement was shown to be the factor for the contrasting unity and diversity. In order not to stimulate this visual confusion, the colors of outdoor advertisement has to be applied on the basis of the color guideline based on the color combination principle of outdoor advertisement and building structure to have the aesthetic harmony overall. As a result of analysis using the KJ method, the present image of the old downtown area was shown with the adjective vocabularies of "complicated", "out-dated", "chaotic", "disorganized", "dirty", "suffocating", and "unilateral", and its image to strive for would be in a total of 6 adjective vocabularies of "well-arranged", "young", "dynamic", "sophisticated", "personable" and "neat", and it has presented the basic foundation of color guideline of outdoor advertisement fit for its image.

• 한국융합학회논문지
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• 제13권4호
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• pp.643-651
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• 2022

메타버스의 급부상에 따라 모바일 증강현실 시장이 빠르게 성장하고 있다. 하지만, 모바일 증강현실 환경에서의 사용자 경험 향상을 위한 연구가 부족한 실정이다. 본 연구는 증강현실 기반의 스마트폰 애플리케이션 사용성 원칙 개발을 목표로 한다. 연구 방법으로 1)모바일 증강현실의 특성을 파악하여 증강현실 애플리케이션의 사용성 요인을 파악했다. 2)증강현실의 사용성 사례 연구 분석을 통해 사용성 원칙을 수집 및 선별하고, 전문가 심층 인터뷰를 통해 사용성 원칙을 재범주화하여 14개의 사용성 원칙으로 개발했다. 3)개발된 사용성 원칙을 검증하기 위해 사용성 원칙을 바탕으로 평가 문항을 구성하여 사용성 평가 설문을 진행했다. 결과적으로 몰입성, 현존감, 효율성, 만족감, 유희성에서 유의미한 차이를 발견하였으며, 증강현실 기반 스마트폰 애플리케이션 개발에 유용한 사용성 원칙임을 검증했다. 본 연구는 증강현실 기반 모바일 사용성 원칙에 관한 기초연구라는 점에서 의의가 있다.

• 한국초등과학교육학회지:초등과학교육
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• 제38권4호
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• pp.439-452
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• 2019

This study aims to compare self- and peer-assessments of science-gifted elementary students' scientific creativity. A science-gifted program on the Pascal's principle was implemented to 40 fifth-graders in the Science-Gifted Education Center for two weeks. After that, students presented their results from a scientific creativity task using the principle in class. The task was to devise a new and useful tool using the principle, and it included the students' self-assessment about their idea. During presentation, students were asked to assess the works of peers and write down the reasons that they gave the scores they gave. Shortly, student self- and peer-assessments about students' scientific creativity outcomes were compared. Based on two essential components of creativity, ideas that satisfy both originality and usefulness can be counted as scientifically creative. The main results of this study are as follows: First, the average scores of student self- and peer-assessments were 71.5 and 61.9. Second, the standard deviations of student self- and peer-assessments were 14.47 and 5.79. Third, among scientific creativity, originality, usefulness scores, only originality had a significant correlation between student self- and peer-assessment (r=.42). Fourth, the students were categorized into four groups according to the levels of their scores by student self- and peer-assessment. And the frequencies of peer-assessment group had a significant difference at p<0.05 level, according to self-assessment group (Chi Square=4.0000, df=1, p=0.0455). Fifth, through a case study by group, the results suggesting that self-assessment could be affected by the students' self-efficacy and perfectionism and such effect could also influence peer-assessment have been found. The result showed that how the student self- and peer-assessment of scientific creativity are different and what the students' thoughts on the evaluation of scientific creativity are. The findings suggested that there are several things to consider for the educators to make efforts to construct consistent assessment methods for scientific creativity.

• 한국항만학회지
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• 제14권1호
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• pp.57-64
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• 2000

For composing the structure model of national maritime power system by system structural modeling, in this study, the 50 basic factors are selected by survey of the extensive and through literatures on maritime, sea, maritime power and sea power. And the basic factors are classified into 36 component factors by cluster method. The 9 attributes are extracted by the application of the principle component analysis method, one of the factor analysis method in system engineering, to component factors. In this study, we define the attributes composing the national maritime power system by integrating the result of this study and existed our studies relating to this topic. Which are showed in Table 2. and we show the structure model of national maritime power system in Fig. 3. In Table 2, the 9 attributes are as follows : the fundamental power of maritime, shipping and port power, naval power, fishing power, shipbuilding power, the power of ocean research and development, dependency on seaborne trade, the protection power of ocean environment and the will and inclination of govemment. Also, in the case of evaluating this system, we conform the importance of considering the interactions among the attributes which have strong interactions in structure model of national maritime power system.