• Journal of Digital Contents Society
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• v.18 no.5
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• pp.803-810
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• 2017

Currently, every person possesses a smart phone due to the development of the IT industry. There is an improper situation in which a smart phone is not set in silent mode, such as a lecture room, a library, and a theatre hall. The proposed system automatically automates the function of smart phones where they are designated as a public place or etiquette area and automatically return the function of the smartphone if they deviate from the location of the site. It is also equipped with a combination of autonomous devices and services, based on Bluetooth communications, which are applied to ultra-light low-power IoT(Internet of Things) devices, and has features that allow diverse types of features and services to be added without requiring deformation of the hardware.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.421-427
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• 2013

Disk Cache Manager(DCM), a functional server of microkernel based, to improve the I/O power of shared disks is designed and implemented in this work. DCM interfaces other different servers with message passing through ports by serving as a system actor the multi-thread mode on the Minix3 micro-kernel. DCM proposed in this paper uses the shared disk logically as a Seven Disk and Sodd Disk to enable parallel I/O. DCM enables the efficient placement of disk data because it raises disk cache hit-ratio by increasing the cache size when the utilization of the particular disk is high. Through experimental results, we show that DCM is quite efficient for a shared disk with higher utilization.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.203-210
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• 2019

Most cars today use electronic control to control the state of the engine to achieve optimum performance. This study developed a device for maintaining fault diagnosis and optimal vehicle status by displaying the engine information of a car on the screen in real time using can communication. This system displays information generated from the engine to the driver in real time such as engine intake and exhaust temperature, current battery voltage, tire pressure, RPM, DPF collection amount, torque, and horsepower through the OBD2 socket. You can check immediately. It can help you to drive safely by measuring tire pressure and displaying it on the screen, and it provides a mode to set the shift timing to suit your taste. In particular, in the case of diesel engine cars, the problems caused by smoke can adversely affect the performance and environmental pollution. Therefore, the system was developed to display the DPF collection amount on the system screen to prevent environmental pollution and to manage the vehicle efficiently.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.339-346
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• 2012

In this paper, equivalent models for active control devices are proposed so that building structures with such devices are analyzed using commercial structural analysis programs for the assessment of the structural members under active vibration control. Equivalent link models represent active control device with a virtual linear spring and dashpot, and equivalent force models are control force history acting at the installation point in structural models. Active controllers are designed based on the reduced-order models for a vertical cantilever model and a high-rise building model and corresponding equivalent models are determined from control gain matrices. Based on acceleration, displacement and member force responses, the effectiveness of the equivalent models is verified. As a result, proposed equivalent models, of which equivalent link model showed better performance, appear to enable detailed investigation of structural behavior to the extent of member force level.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.67-74
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• 2013

IGCC(Integrated Gasification Combined Cycle) system is candidates which can solve the environmental problems including global warming, since it can be easily combined with CCS(Carbon Capture System). In this research, combustion instability characteristics were studied at various fuel which are composed of $H_2/CH_4/CO$ mixture. Mode analysis for instabilities observed experimentally was conducted and the linearly increasing tendency of frequency was observed as the hydrogen content in fuel increases.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.213-220
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• 2005

Carbon fiber reinforced polymer (CFRP) sheets are becoming increasingly popular for strengthening deteriorated concrete bridges due to their excellent strength and stiffness-to-weight ratio, corrosion resistance, and convenience of construction work. The purpose of this study is to compare the performance of CFRP-strengthened reinforced concrete (RC) beams and to develop a new design formula. Simple beams with 3 m span length were tested to investigate the effect of reinforcing steel ratio and CFRP-reinforcing ratio on the flexural behavior of strengthened RC beams. The test results were analyzed with the special emphasis on the failure mode, the maximum load, and the strain distribution in the section. It is shown that the strain of the strengthened beams is not linearly distributed in the section. A new design formula based on the non-linear distribution of the strain has been derived and showed that it has a good agreement with the various domestic and foreign test results.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.501-501
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• 2015

댐과 같은 수공구조물의 치수능력부족은 구조물의 파손이나 붕괴로 직결되며, 대규모 재산피해와 인명피해가 불가피하다. 또한 최근 기후변화 현상에 의해 발생되고 있는 예상치 못한 큰 강우와 홍수는 댐 안전을 저하하는 요소로 간주되며, 복합적으로 발생시 댐의 치수능력이 크게 저하되어 댐 파괴에 영향을 미칠 가능성이 크다. 또한 ICOLD, 세계대댐회 등의 조사 결과 댐 파괴에 큰 영향을 미치고 있는 수문학적 요소로서 예상치 못한 강우, 홍수 및 월류로 조사되었다. 이러한 이유로 수문학적 위험인자를 효과적으로 고려하기 위해 2000년도 이후 선진국에서는 위험도 해석 기법을 기반으로 파괴모드, 다양한 하중조건 등을 조합하여 위험도 해석을 통해 댐의 안전도 검토를 실시하고 있다. 따라서 최근 증가하는 기상변동성을 능동적으로 고려하기 위해서는 위험도 해석기반의 수공구조물 안정성 평가기법을 기반으로 하는 종합적인 위험도 해석 방안수립이 요구된다. 이러한 이유로 본 연구에서는 BN 모형 기반의 댐 위험도 적용에 앞서 실증댐을 대상으로 분석을 수행하였으며, 분석 절차는 다음과 같다. 첫째, ICOLD 및 세계대댐회 등 다양한 논문, 보고서 등을 조사하여 댐 붕괴에 가장 큰 영향을 미치는 수문학적 파괴인자를 도출하였다. 둘째, BN 모형 구축시 각 노드는 앞서 도출된 수문학적 파괴인자를 이용하였으며, 각 파괴인자에 적합한 확률분포형을 부여하였다. 마지막으로, 노드별 임계값을 부여하여 상황별 파괴인자의 변화 양상을 도출하였다. 본 연구의 결과로 인해 연구대상댐의 가장 취약한 수문학적 파괴인자 도출이 가능하며, 댐의 보수 보강시 우선순위 의사결정의 지원이 가능 할 것으로 판단된다.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.157-164
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• 2021

This study was conducted to investigate students' perception of the integration of Chinese ethnic minority culture into the college EFL teaching which was carried out in the fall and spring semesters with different presentation topics. One and the same questionnaire was distributed to 61 participants, involving Han Chinese and Chinese ethnic minority students, at a university in ethnic minority area in China at the end of each semester, and SPSS 20.0 was used for t-test to analyze the data. The research results showed that Chinese undergraduates have got more significant improvements in cultural cognition, emotions, attitudes, and multi-cultural values in the spring semester than those in the fall semester. All participants benefit a lot from multi-cultural activities without significant differences between Han Chinese and ethnic minority students in both semesters. It is suggested that ethnic minority culture be integrated into the college EFL teaching, along with English culture and Chinese mainstream culture, which be administered as a practical teaching mode to develop students' intercultural competence.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.617-625
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• 2022

This study attempted to compare and analyze metaverse platforms according to their functions. The five metaverse platform was selected and comparatively analyzed through in-depth interviews with experts. As a result of the research, first, Roblox allows you to create and customize your own avatar, provides studio functions for free, and allows you to enjoy private games with friends. Second, Zepeto can create an avatar with one selfie and provides a creative studio function. Third, in Fortnite, it is possible to create in-game characters, purchase and wear items provided in the game, and play games with friends in Creative Mode. Fourth, in Gather Town, networking with users in virtual space is possible, and your own avatar customization and desired virtual space template are provided. Finally, Facebook Horizon participates in the virtual world Horizon with its own avatar that you decorate yourself, and it can function as a world builder, and you can set up a billboard in virtual reality or a virtual store. The value of this study provided a theoretical basis that can be applied to the future industry through the characteristics of the metaverse platform.

• Transactions of Materials Processing
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• v.31 no.1
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• pp.29-38
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• 2022

Recently, the composite material market is gradually growing. Various composite forming processes have been developed in order to reduce the production cost of the composite material. Unlike the conventional forming process, the microwave composite forming process has the advantage of reducing the processing time because the composite material is heated directly or indirectly at the same time. Due to this advantage, in this study, a double cantilever beam test was conducted with specimens manufactured by the microwave composite forming process. The purpose of this study was to compare mode-I energy release rate for specimens manufactured by prepreg compression forming and microwave composite forming processes. First, a microwave oven was proposed to conduct the microwave composite forming process. Double cantilever beam specimens were manufactured. After that, the double cantilever beam test was conducted to obtain the mode-I energy release rate. Mode-I energy release rates of specimens manufactured by the microwave composite forming and prepreg compression forming processes were then compared. As a result, mode-I energy release rates of specimens fabricated by the microwave composite forming process were similar to those fabricated with the prepreg compression forming process with a relatively reduced process time.