• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.40-48
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• 2018

This paper presents a simulation-based design reliability estimation method of a low-energy exploding foil initiator (LEEFI) using a meta-model and describes the design reliability estimation results. The flyer velocity of the LEEFI is critical to initiate the explosive. Evaluation of the flyer velocity from mechanistic models in open literature requires a long computation time due to the multi-physical phenomena that generate the velocity. Moreover, the higher levels of confidence required for an initiator with high reliability incur higher computation costs. Thus, a meta-model of the flyer velocity over time was constructed in order to increase the computational efficiency for a reliable estimation. For different distributions and sigma levels of the design variables, the design reliability estimation results using the meta-model are provided. Additionally, the computational efficiency and accuracy of the estimation method are analyzed.

• Explosives and Blasting
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• v.39 no.1
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• pp.1-9
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• 2021

As the national economic growth and the rapid increase in industrial structures are aging, the demand for removing steel structures is increasing, and research on improving the penetration performance of the linear shape charge explosives. In the study, numerical analyses were performed on the effect of the type of explosive used in the self-made shape charging container and the initiation method on the cutting performance of the steel plate and the effect on the shaped explosive installed close to it. ANSYS LS-DYNA, which can analyze the large deformation problem of materials due to explosion, was used, and an ALE(Arbitrary-Lagrange-Eulerian) model was applied that enables interlocking analysis of gases, liquids, and solid.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.5
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• pp.359-365
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• 2022

Air-to-ground missile(AGM), which can be operated by being mounted on the outside of the aircraft, is capable of precision strikes, ensuring high survivability. Helicopter, which is one of the AGM operating platforms, is reported to experience a lightning strike once between 1000 and 20000 flight hours in average. When the lightning strikes the helicopter fuselage, lightning transient signal can be induced to internal and external electronic equipment cables through the skin of the helicopter. If the transient signal exceeding the criteria to electrically initiated device(EID) related to the explosive in the AGM can affect the safety of the helicopter by a warhead explosion, etc. In this paper, we suggest an indirect lightning test method to prove the safety of AGM on helicopter, and present the indirect lightning test results.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.237-245
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• 2019

Entry of women into the higher positions or professions in the fields of entertainment and performing arts has been expanding gradually. Especially, women working in these fields in New York show a dynamic growth and development. As a result, women surviving in a male-dominated world have raised their voices for their human rights to live free from violence, sexuality, slavery, discrimination, etc.. In the entertainment and performing arts, women have been shouting their voices for a long time through the theme, performance process, and the shows. Their voices influenced politics, society, and culture as a whole. The 'MeToo' movement is the result of condensation from their voices. In other words, it is the result of women's voices against sexual harassment or assault in these fields. Starting in Hollywood, the 'MeToo' movement was rapidly spread out online and strongly supported by female leaders and activists in the world. It had a strong influence on the fields of theater and entertainment industry in Korea as well. By recognizing this phenomenon, the contents of this study suggest how and what to continuously increase the value of the 'MeToo' movement in Korea's entertainment industry.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.665-675
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• 2008

The objective of this paper is to provide an approximate cost estimating model for tunnel that can be utilized both in quick construction cost estimating for design alternatives, and in evaluating efficiently the cost effects according to the environmental changes during design and construction stage. To meet this requirement, this study analyzes critical cost factors influencing tunnel construction costs. The cost factors include 7 elements such as rock drilling method, advancing method, type of detonator, loader capacity, unit weight and soil volume change factor, length of tunnel. This paper investigates the cost variance according to the change of the cost factors. The result is expected to be used in formulating approximate tunnel cost estimating model.

• Explosives and Blasting
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• v.30 no.2
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• pp.29-42
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• 2012

Variables influencing the free face movement due to rock blasting include the physical and mechanical properties, in particular the discontinuity characteristics, explosive type, charge weight, burden, blast-hole spacing, delay time between blast-holes or rows, stemming conditions. These variables also affects the blast vibration, air blast and size of fragmentation. For the design of surface blasting, the priority is given to the safety of nearby buildings. Therefore, blast vibration has to be controlled by analyzing the free face movement at the surface blasting sites and also blasting operation needs to be optimized to improve the fragmentation size. High-speed digital image analysis enables the analyses of the initial movement of free face of rock, stemming optimality, fragment trajectory, face movement direction and velocity as well as the optimal detonator initiation system. Even though The high-speed image analysis technique has been widely used in foreign countries, its applications can hardly be found in Korea. This thesis aims at carrying out a fundamental study for optimizing the blast design and evaluation using the high-speed digital image analysis. A series of experimentation were performed at two large surface blasting sites with the rock type of shale and granite, respectively. Emulsion and ANFO were the explosives used for the study. Based on the digital images analysis, displacement and velocity of the free face were scrutinized along with the analysis fragment size distribution. In addition, AUTODYN, 2-D FEM model, was applied to simulate detonation pressure, detonation velocity, response time for the initiation of the free face movement and face movement shape. The result show that regardless of the rock type, due to the displacement and the movement velocity have the maximum near the center of charged section the free face becomes curved like a bow. Compared with ANFO, the cases with Emulsion result in larger detonation pressure and velocity and faster reaction for the displacement initiation.

• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.41-50
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• 2018

The present article focuses on the cultural arts, the role and functions of people as intermediate to carry out the revitalization of memory. Most of the basic cultural activities and events sparked from the cardinal point of the democratization of Gwangju and the interwoven relationships this created. In other words, the events leading to Gwangju democratization movement have derived from democratic culture and art and they contributed to change and influence South Korea's revolutionary movements. As far as clarifying the concept of culture is concerned, the idea of culture is too wide to encompass it so we aim to narrow it down to the special events of 5.18 democratization movements which launched the national transformation of the cultural stage and the development of democracy in South Korea. Through this, the movement of popular culture and popular arts fostered the revolution of society. Moreover, the value of the 5.18 movement for democratization stems from democracy, human rights, the universal value of peace and so many efforts were made by popular artists until it became upgraded as a national commemoration day. Raising the people's awareness that culture could change the course of history is still necessary so that popular art and culture play a central role in people's lives. In order to fulfill the people's inherent hope it is necessary to promote aesthetic values and a continuous revolution in societal practices.

• Culinary science and hospitality research
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• v.16 no.2
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• pp.136-154
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• 2010

This study aims to suggest theoretical models to examine the composition factors of recognition, image, attitude toward Korean food and its globalization and investigate their relationships, which was analyzed based on the results of a survey. To achieve this research purpose, frequency analysis, exploratory factor analysis and the analysis of Cronbach a values were performed using the SPSS 13.0 program, and multiple regression analysis and simple regression analysis were also performed to analyze their relationships. The results of this study are as follows. First, the recognition of Korean food influenced its image and attitude toward it. Second, image of Korean food had an effect on attitude toward it. Third, both image and attitude regarding Korean food influenced globalization of Korean food. Accordingly, what this study can contribute to in the development of Korean food culture are as follows. First, this study will contribute to making a good image of Korean food and its globalization by changing people's recognition, image, and attitude toward Korean food and making them interested in Korean food suitable for globalization. Second, this study will help to make detailed marketing strategies to globalize Korean products and culture through Korean food. Third, this study will be helpful for improving the image of Korean food and creating economic benefits by attracting Korean food tourism. Moreover, it will help to give Korean people hope and pride of their lives. Fourth, this study will help to promote activation of Korean food tourist resources by connecting Korean food recognized to be LOHAS and well-being foods with Korean cultural tourist resorts. Fifth, this study will make people have right recognition and attitude by developing nature-friendly and healthy Korean food culture. Sixth, this study will be a detonator for more active studies by encouraging researchers to be concerned about and participate in globalization and commercialization of Korean food continually.

• Tunnel and Underground Space
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• v.13 no.3
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• pp.187-195
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• 2003

This case study which is to make 2-Dimension earth's crust structures clearly is about the great boring-hole blasting to provide ground vibration source of the reflected wave research on the Korean Peninsula earth's crust structures research. For this study we've done blasting twice-500 ㎏/charge per delay, 1,000 ㎏/charge per delay, and the specifications of blasting are the following - dia.: 300 ㎜, boring-depth : 100m, besides, we used the explosives and electric detonators which have sufficient detonating velocity and very excellent safety, capacity of detonating, accurate delay time. We charged explosives into steel pipe with bulk type to avoid dead pressure by ground water. And then we tested about pipe airtight and blasting to certificate which has no problem by using on this study. In the results, we succeeded each blasting in Seosan, Youngdong. For the Peak Sum Vector(PSV) around the blasting at the main points, its real measured PSV is higher 180 % than estimated PSV with USBM. In this study we can't to be analysis of vibration velocity, but to be key providing vibration source.

• Explosives and Blasting
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• v.34 no.4
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• pp.19-27
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• 2016

Much care should be taken when electric caps are used in blast site than when non-electric initiation systems are used. This is because electric caps can cause premature firing or misfires if stray currents of high magnitude flow into the blasting circuit. If the rock has higher electrical conductivity or lower electrical resistivity, such risks will be increased because the rock will provide more passages for the stray currents to flow into the blasting circuit. In this study, several rock samples obtained at a blast site were tested for electrical resistivity to decide whether electric caps could be used or not in the site. The measured electrical resistivity was $39{\sim}47{\Omega}{\cdot}m$ for the rock samples that had a higher content of metal sulfides. Contrary, the resistivity was $15000{\sim}21000{\Omega}{\cdot}m$ for ordinary rocks. Especially, in the case of the rock of electric resistivity of $39{\Omega}{\cdot}m$, only 2-V electric potential enables a stray current to flow through the rock of 1-m length, which can cause the premature firing of a detonator whose initiation current is 0.4 A. This result shows that electric initiation system should not be used in the site because rocks containing much amount of metal sulfides are widely distributed there.