• 콘크리트학회논문집
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• 제28권5호
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• pp.545-553
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• 2016

이 논문에는 교량바닥판의 지간장이 짧은 단지간용 프리캐스트 콘크리트패널에 대해 수행한 정적하중 재하실험 결과들을 나타내었다. 단지간용 콘크리트패널은 콘크리트패널 하면에 콘크리트리브가 부착되어 있으며, 기존 LB-DECK과 달리 콘크리트패널 상면에 Top bar가 없는 단면이다. 콘크리트패널에 부착되는 콘크리트리브의 개수와 단면 상세는 교량바닥판의 지간장과 철근콘크리트바닥판 두께 변화에 따른 설계하중에 대해 변수해석 결과를 토대로 결정하였다. 콘크리트패널 상면에는 현장타설되는 콘크리트와 합성거동을 위해 전단철근을 배치하였다. 변수해석을 통해 산정된 콘크리트패널이 설계하중에 대해 사용성과 안전성을 만족하는 가를 확인하기 위해 정적하중 재하실험을 수행하였다. 지간장 1.6 m인 단지간 콘크리트패널 실험체 3개 제작한 후 정적하중 재하하면서 각 실험체의 처짐, 균열, 그리고 최종 파괴양상을 살펴보았다. 설계하중이 작용할 때 각 실험체의 처짐, 균열하중, 그리고 균열폭을 토대로 사용성을 평가하였다. 또한 각 실험체의 최종 파괴양상과 극한강도를 토대로 계수설계하중에 대한 안전성을 평가하였다. 실험 결과 단지간용 콘크리트패널이 사용성과 안전성을 만족하는 것을 확인할 수 있었다. 추가적으로 단지간용 콘크리트패널을 적용할 수 있는 교량바닥판의 지간장 범위를 검토하였다.

• 한국안전학회지
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• 제33권3호
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• pp.15-20
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• 2018

There have been a number of major fatal fire accidents in Korea recently. The number of fires in 2017 were 44,178, which is not only increasing number of fires but also increasing in casualties. Particularly, the fire at Jecheon Sports Center, which suffered many casualties, is expected to have a huge impact. The cause of the fire has not been determined yet, but heat waves on the ceiling have also been pointed out. As such, the copper heating waves, which are used as a preventive measure against damage of pipes due to freezing of pipes, etc., always have a fire hazard. To determine the possibility of a flame-resistant heated fire, a positive electric cable product was used to artificially ignite and analyze the results. In case of a short circuit, the external covering of the positive electric cable is damaged, but not short circuit unless the heating material surrounding the wire is damaged. Due to the characteristics of heating cable for preventing copper waves, the chances of insulation becoming more severe due to moisture and temperature changes are higher than normal wires. If the internal heating system is carbonized by insulating deterioration without damage to the outer coating, it is likely to cause trekking, to form a winding loop in the heating materials, and to cause short circuit in the heated materials. For the positive temperature line, if the middle is shorted, the current continues to flow to the short circuit unless the breaker disconnects. Consequently, a heated fire that does not cut off the power immediately may leave multiple marks or cuts.

• 비파괴검사학회지
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• 제23권3호
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• pp.246-253
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• 2003

항공기 구조를 모사하여 일련의 리벳 구멍을 갖는 AA2024-T3 박판 구조를 대상으로 피로하중에 의한 단균열(short crack)의 발생시점과 성장거동을 음향방출(AE)을 위주로 한 측정으로 평가하였다. AE 위치표정에 의해 단균열의 좌표를 정확하게 결정하였으며, 이동식 현미경으로 균열의 크기를 측정하였다. 누적 AE 발생수 곡선은 단균열의 발생과 성장에 따라 일정한 간격을 두고 급격히 증가하는 양상을 보임으로써 여러 차례의 계단식 곡선을 형성하였다. AE 위치표정에서는 리벳 구멍을 중심으로 파괴역학에 근거한 관심영역(ROI)을 설정하였으며, 웨이블릿변환 잡음제거 방법을 사용하여 위치표정의 정확도를 향상할 수 있었다. 실제로 탐지된 신호의 대부분이 단 균열의 발생 및 성장과 관계없는 외부 잡음신호로 나타났으며, ROI 내에서 발생한 AE 발생원의 위치도 구조의 기하학적 특징이나 신호대잡음비의 영향에 의해 왜곡될 수 있음을 알 수 있었다.

• International Journal of Contents
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• 제17권1호
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• pp.37-53
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• 2021

With the advent of the 5G era, smart phones and communications network technology have progressed, and mobile short video of people's life can be made, Of the new tools of communication, at present, China's social short video industry has shown rapid development, and the most representative of the short video app is Douyin (international version: Tiktok). Under the background of Uses and Gratifications Theory, this study discusse the relationship between Douyin users' preference degree, use motivation, use satisfaction and attention intention. This study divides the content of Douyin video into 10 categories, selects the form of an online questionnaire survey, uses SPSS software to conduct quantitative analysis of 202 questionnaires after screening, and finally draws the following conclusions: (1) The content preference degree of Douyin short video (the high group and low group) is different in users' use motivation, users' satisfaction degree and users' attention intention. ALL results are within the range of statistical significance.(2) Douyin users' video content preference degree has a positive impact on users' use motivation, users' satisfaction degree, and users' attention intention. (3) Douyin users' motivation has a positive impact on users' satisfaction and user' attention intention. (4) Douyin users' satisfaction degree has a positive impact on users' attention intention. Based on the research results, we suggest that Douyin platform pushes videos according to users' preferences. In addition, as the preference degree has an impact on users' motivation, satisfaction degree and attention intention of using the platform, it is important that the platform's focus should to pay attention to the preference degree of users. Collecting users' preferences at the early stage of users' entering the platform is a good way to learn from, and doing a good job of big data collection and management in the later operation.

• Computers and Concrete
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• 제32권5호
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• pp.455-464
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• 2023

Seismologists now suggest that the earth has entered an active seismic period; many earthquake-related events are occurring globally. Consequently, numerous casualties, as well as economic losses due to earthquakes, have been reported in recent years. Primarily, significant and colossal damage occurs in reinforced concrete (RC) buildings with masonry infill wall systems, and the construction of these types of structures have increased worldwide. According to a report from the Ministry of Education in the Republic of Korea, many buildings were built with RC frames with masonry infill walls in the Republic of Korea during the 1980s. For years, most structures of this type have been school buildings, and since the Pohang earthquake in 2017, the government of the Republic of Korea has paid close attention to this social event and focused on damage from earthquakes. From a long-term research perspective, damage from structural collapse due to the short column effect has been a major concern, specifically because the RC frame with a masonry infill wall system is the typical form of structure for school buildings. Therefore, the short column effect has recently been a major topic for research. This study compares one RC frame with four different types of RC frames with masonry infill wall systems. Structural damage due to the short column effect is clearly analyzed, as the result of this research is giving in a higher infill wall system produces a greater shear force on the connecting point between the infill wall system and the column. The study is expected to be a useful reference for research on the short column effect in RC frames with masonry infill wall systems.

• 패션비즈니스
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• 제13권6호
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• pp.137-146
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• 2009

This study analyzed hierarchy of image for visual evaluation of flare skirt. This study analyzed expression words about flare skirt with frequency data of image expression words with different length and volume of flare. Stimuli for the study were set to be 4 different volume of flare ($90^{\circ}$, $180^{\circ}$, $270^{\circ}$, $360^{\circ}$) and 3 different length of skirt(48cm, 58cm, 68cm). Stimuli were made by using I-Designer which is Virtual Sewing System. From simulation of flare skirt, the subjects were asked to write down suggested adjective freely and selected 210 adjectives. With this, we chose total 38 adjectives considering frequencies in the pre-study. And we analyzed the combination process of expression words according to construction factor of flare skirt and hierarchy of image from dendrogram which was resulted by hierarchical cluster analysis. 'Feminine' got high score in all 12 flare skirt. When the skirt was short, it was vivid, and as the skirt got longer, ordinary and pure image showed. Also, as the volume of flare got larger, the average of visual effect was higher than visual image. Visual hierarchy construction according to construction factors of flare skirt could be divided into visual image and visual effect, and visual image was shown to be form 'A type - large volume of flare and short skirt length', 'H type-small volume of flare and short skirt length' and 'X type - large volume of flare and long skirt length'.

• Journal of Welding and Joining
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• 제8권1호
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• pp.31-42
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• 1990

Arc must be stable during welding first of all other factors for obtaining sound weldment, especially in the automation of welding process. Arc stability is somewhat sophisticated phenomenon which is not clearly defined yet. In consumable electrode welding, the voltage and current variation due to metal transfer enables to assess arc stability. Recently, statistical analyses of the voltage and current waveform factors are performed to assess the degress of arc stability which is assessed and controlled by operator's own experience by now. But, considering the increasing need and the trend of automation of welding process, it is necessary to monitor arc stability in real-time. In this sutdy, the modified stability index composed of two voltage and current wvaeform factors (arc time and short circuit time) reduced from four factors (arc time, short circuit time, average arc current and average short circuit current) in Mita's index by the welding electrical circuit modeling is proposed and verified by experiments to be well estimating arc stability in the static sense. Also, the recursive calculation form estimating present arc stability in the dynamic sense is developed for real-time estimation. The results of applying the recursive index during welding show good estimation of arc stability in real-time. Therefore, the results of this study offers the mean for real-time control arc stability.

• 수산경영론집
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• 제28권1호
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• pp.85-117
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• 1997

This paper is focused on management control system. From a management control perspective, strategies should be viewed as useful, but not absolutely necessary, guides to the proper design of an MCS. When strategies are formulated more clearly, more control alternatives become feasible and it becomes easier to implement each form of management control effectively. The common and important category of controls are action controls, personnel and cultural controls, and results controls. Action controls involves ensuring that employees perform(or do not perform) certain actions that are known to be beneficial(or harmful) to the organization. Personnel and cultural controls take steps to ensure that employees will control each others' behaviors. Results controls involve rewarding individuals(and sometimes groups of individuals) for generating good outcomes or punishing them for poor outcomes. The results controls of ROI-type measure cause to make managers excessively short- term oriented, or myopic. When managers' orientations to the short - term become excessive -when the management are more concerned with short-term profit than entity value-the managers are said to be myopic. We car, solve myopic problem by introducing AR(abnormal return), near-perfect indicators of value creation. The results - control ideal would be to hold all employees accountable for the wealth they individually create(or destroy) for the owners of the entities in which they work. This ideal is approachable for top management of publicly traded corporations because for these organizations, the wealth created(returns to shareholders) can be measured directly for any period(such as a year, a quarter, or a month) as the measurement period pin(or minus) the change in the market value of the stock.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권6호
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• pp.585-593
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• 2015

In the nanoscale regime, many multigate devices are explored to reduce their size further and to enhance their performance. In this paper, design of a novel device called, Triple Material Surrounding Gate Tunnel Field effect transistor (TMSGTFET) has been developed and proposed. The advantages of surrounding gate and tunnel FET are combined to form a new structure. The gate material surrounding the device is replaced by three gate materials of different work functions in order to curb the short channel effects. A 2-D analytical modeling of the surface potential, lateral electric field, vertical electric field and drain current of the device is done, and the results are discussed. A step up potential profile is obtained which screens the drain potential, thus reducing the drain control over the channel. This results in appreciable diminishing of short channel effects and hot carrier effects. The proposed model also shows improved ON current. The excellent device characteristics predicted by the model are validated using TCAD simulation, thus ensuring the accuracy of our model.

• 대한방사선기술학회지:방사선기술과학
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• 제43권5호
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• pp.389-395
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• 2020

The evaluation of radioactivated components of heavy-ion accelerator facilities affects the safety of radiation management and the exposure dose for workers. and this is an important issue when predicting the disposal cost of waste during maintenance and dismantling of accelerator facilities. In this study, the FLUKA code was used to simulate the proton treatment device nozzle and classify the radio-nuclides and total radioactivity generated by each component over a short period of time. The source term was evaluated using NIST reference beam data, and the neutron flux generated for each component was calculated using the evaluated beam data. Radioactive isotopes caused by generated neutrons were compared and evaluated using nuclide information from the International Radiation Protection Association and the Korea Radioisotope association. Most of the nuclides produced form of beta rays and electron capture, and short-lived nuclides dominated. However, In the case of ⁵⁴Mn, which is a radioactive product of iron, the effect of gamma rays should be considered. In the case of tritium generated from a material with a low atomic number, it is considered that handling care should be taken due to its long half-life.