• Journal of the Korea Convergence Society
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• v.4 no.3
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• pp.1-5
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• 2013

This study deals with simplified load calculation and structural testing for scale down model of small wind turbine blade. First, the blade was designed and produced scale down to 0.2 ratio of initial blade. And moments were acquired by simplified load calculation equations according to IEC 61400-2 standard. Also, structural test using weight was conducted to obtain the maximum moment. Therefore maximum moments were compared at calculation and test.

• Convergence Security Journal
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• v.14 no.3_1
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• pp.55-63
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• 2014

The history of mankind has been at war with the war now going on in this moment. To prepare for this war, war history has been studied and its importance can be summarized in three main points. First, to understand the predictions of war and, second, to develop doctrines to fit changing circumstances, and to hone tactics through indirect war experiences. The curriculum of war history education for noncommissioned officer's department(two-year program) must include war lessons and skills to prepare the war. By indirect experiences through training they will have the ability to perform their duties in the field. This paper focuses to review the contents and methods of war history education which is being taught and to propose the new model for war history education for the students who are commissioned as officers after graduation.

• Journal of the Korean Society of Costume
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• v.59 no.3
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• pp.27-41
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• 2009

Interpreting the phenomenon of Fast fashion that is prevalent these days, this research is meaningful in that it prepares the frame which suggests the vision to read the trend of 2000s and analyzes the property of phenomenon of Fast Fashion in the connection with society and culture. The so[io-cultural property can be largely characterized by consumption orientation, change orientation, efficiency, moment and multiculturism. Analyzing the phenomenon of fast fashion that emerged after 2000 on the basis of such sociocultural background, it is largely classified into imitation, fashionability, disposability, portability, transformation and convergence. Due to the hi-polarization of consumption, people tend to select imitated goods, and people accustomed to speed get interested in the fashionability of all Phenomena. Further, society that is transient and changing rapidly makes the habit of purchasing in disposability. The property of nomad society encourages to keep the habit of portability. Such change-oriented society and rapidly changing life pattern make them adapt in diverse transformation modes of Fast Fashion. Further, multi-cultural world integrates enterprises through combination of all cultures and the convergence of all factors.

• Structural Engineering and Mechanics
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• v.20 no.3
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• pp.293-312
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• 2005

In this paper, free vibration of rotating beam with random properties is studied. The cross-sectional area, elasticity modulus, moment of inertia, shear modulus and density are modeled as random fields and the rotational speed as a random variable. To study uncertainty, stochastic finite element method based on second order perturbation method is applied. To discretize random fields, the three methods of midpoint, interpolation and local average are applied and compared. The effects of rotational speed, setting angle, random property variances, discretization scheme, number of elements, correlation of random fields, correlation function form and correlation length on "Coefficient of Variation" (C.O.V.) of first mode eigenvalue are investigated completely. To determine the significant random properties on the variation of first mode eigenvalue the sensitivity analysis is performed. The results are studied for both Timoshenko and Bernoulli-Euler rotating beam. It is shown that the C.O.V. of first mode eigenvalue of Timoshenko and Bernoulli-Euler rotating beams are approximately identical. Also, compared to uncorrelated random fields, the correlated case has larger C.O.V. value. Another important result is, where correlation length is small, the convergence rate is lower and more number of elements are necessary for convergence of final response.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.3
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• pp.161-168
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• 2010

Recently, bridges have been momenttous as not only regarding function but also concerning aesthetics. However, when beauty is considered in the bridge, it is also essential that stability and economics be considered. Besides, when considering stability, an arch bridge is one of the most stable structures. The most important element is a rise ratio when regarding beauty and economics of arch bridges. The effect of dead load and DB24 load have been considered to decide proper rise ratio. Therefore, in this study, examined the value of moment, displacement and member forces, in the variation of the rise ratio of arch bridges. The most optimum shape of Nielsen arch bridges has determined by analyzing member forces, moments and displacement with parameters of rise ratio and angle of vertical members. By comparison between values, the hanger types have been also considered to derive the optimum shape of Nielsen arch bridge.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.53-59
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• 2021

The purpose of this study is to develop a damper that protects against the dangers of tidal waves since there's no function to block the inflow of large amounts of water into the inside When natural disasters such as tidal waves occur. Therefore, it intended to derive the design data by simulating through flow analysis in order to predict the pressure that a damper configured to open and close manually or automatically receives. It examined the preceding researches first and conducted the flow analysis, to predict the force of the damper installed on the bottom of the building's outside to prevent the inflow of seawater into the inside when natural disaster occurring. As a result, it showed that, in the event of a tsunami, it moved about 170m and the time impacting the damper occurred within about eight seconds, and, at the moment, the damper door was pressured about 17bar. Also, it could identify that the load was approximately 900kN and the force by the fluid was applied to the damper door.

• Convergence Security Journal
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• v.20 no.5
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• pp.75-80
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• 2020

Damage caused by ransomware has continued to increase since last year, but cyber operations are managed without any separate classification of ransomware types in the military's guidelines for carrying out cyber operations. However, unlike other malware, ransomware is a threat that could paralyze all defense operations in one moment, and the military should reevaluate ransomware and take countermeasures. Accordingly, this paper aims to analyze the assets, vulnerabilities, and threats related to defense information service based on information security risk management, and propose alternatives to ensure continuity of defense work from ransomware threats.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.839-847
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• 2020

The purpose of this study was to analyze the effects of ankle flexibility, gender, and Q-angle on the ankle joint injury factors during one leg drop landing. For this study, 16 males(age: 20.19±1.78 years, mass: 69.54±10.12 kg, height: 173.22±4.43 cm) and 16 females(age: 21.05±1.53 years, mass: 61.75±6.97 kg, height: 159.34±4.56 cm) in their 20's majoring in physical education using the right foot as their dominant feet were selected as subjects. First, an independent t-test of joint motion and joint moment according to the experience of ankle injury was conducted to determine the effect of physical characteristics on ankle joint injury during one leg drop landing(α = .05). Second, the variable that showed a significant difference through t-test was set as the dependent variable, and the ankle flexibility, gender difference, and Q-angle were designated as independent variables to use Multiple Linear Regression(α =. 05). As a result of this study, it was found that the group that experienced an ankle joint injury was found to use a landing strategy and technique through adduction of the ankle joint and internal rotation of the knee joint, unlike the group without an injury. It was also confirmed that this movement increases the extension moment of the ankle joint and decreases the extension moment of the hip joint. In particular, it was found that the dorsi flexion flexibility of the ankle affects the ankle and knee landing strategy, and the gender difference affects the ankle extension moment. Therefore, it was confirmed that physical characteristics factors affecting ankle joint injuries during one leg drop landing.

• Journal of the Korea Convergence Society
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• v.11 no.4
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• pp.49-54
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• 2020

The purpose of this study was to investigate the correlation between sports incidence and heart rate variability in nationa lfemale judo athletes. Participants measured heart rate variability using the Autonomic Nervous System(SA-6000). Based on the average incidence of injury, sports injury incidence was classified into upper and lower groups. In addition, Pearson's Product Moment Correlation was performed to examine the correlation between the independent T-test, the number of sports injuries, and the heart rate variability. Heart rate variability was significantly different in total power and low frequency, and there was also significant difference in otal power and low frequency in the correlation analysis of heart rate variability according to the number of sports injuries. These data are expected to be useful as basic data for developing prevention injury programs.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.239-247
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• 2020

This study is about design and verification of stress reduction of bearings for wind turbines. In a slewing bearing having a typical four-contact structure, the contact point moves to the end of the raceway due to a large moment load, resulting in a stress concentration. A bearing was designed to reduce such contact point movement. The deformation behavior of typical ball bearings and newly designed bearings was calculated through finite element analysis under ultimate load by replacing the ball with a spring element. The contact stress between the ball and the raceway was calculated by finite element analysis by inputting the deformation behavior analysis result as a boundary condition. The effectiveness of the bearing stress analysis method using spring elements was verified through comparison of the contact stress according to the bearing structure.