• 소성∙가공
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• 제15권4호
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• pp.333-339
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• 2006

Hot deformation behavior of a carbon steel (A350 LF2) was characterized by compression tests in the temperature range of $800-1250^{\circ}C$ and the strain rate range of $0.001-10s^{-1}$, The microstructural evolution during hot compression was investigated and deformation mechanisms were analyzed by constructing a deformation processing map. Processing maps were generated using the combination of dynamic material model (DMM) and flow instability theories based on the flow stability criteria and Ziegler's instability criterion. In order to evaluate the reliability of the map, the mirostructural characteristics of the hot compressed specimens were correlated with test conditions in the stable and unstable regime. The combined microstructural and processing map of A350 LF2 was applied to predict an optimum condition and unstable regions for hot forming.

• Korea-Australia Rheology Journal
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• 제14권2호
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• pp.57-62
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• 2002

The sensitivity of the final filament to the ongoing sinusoidal disturbances has been Investigated in the viscoelastic spinning using frequency response method. Amplification ratios or gains of the spinline cross-sectional area at the take-up to any disturbances show resonant peaks along the frequency regime, where the frequencies at theme points directly correspond to the imaginary parts of the successive leading eigenvalues from the linear stability analysis. As shown in Jung et al. (1999) and Lee et al (2001), the sensitivity results on the effect of various process conditions such as spinline cooling and fluid viscoelasticity, obtained by dynamic transient simulation have been corroborated in this study. That is, increasing spinline cooling makes the system less sensitive to disturbances, thus stabilizes the spinning. Also, an increasing viscoelasticity for extension-thickening fluids decreases the sensitivity of the spinning. i.e., stabilizing the system, where, as it increases the sensitivity of the spinning of extension-thinning fluids. Furthermore, it has been found in the present study that the inertia force as one of secondary forces causes the system to be more stabile or less sensitive to process disturbances.

• 인터넷정보학회지
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• 제14권3호
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• pp.35-51
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• 2013

The Digital Cold War argument has become one of the heatedly discussed foreign policy agendas in the U.S. Considering the authority and power of the U.S. government and Internet companies in the cyberspace, this shift is not negligible in understanding not only the changes in the U.S. foreign and military policies but also that in the operations of the global Internet governance. Given these circumstances, I seek to explain the origins of and test the theoretical validity of the Digital Cold War argument. In particular, I analyze how the political concerns of the Chinese authorities shaped the characteristics of their control of the domestic Internet and their approach to the global Internet governance. The findings indicate that the Chinese way of the Internet governance is more concerned of their domestic political stability than overthrowing the current Internet governance regime, which many supporters of the Digital Cold War argument cited as the key evidence of such political contentions. Though the Digital Cold War argument is theoretically unwarranted, its growing popularity and the historical lessons of the Cold War have broad implications to the understanding of the impacts of the great power rivalries on the future Internet governance.

• 트랜스-
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• 제2권
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• pp.39-58
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• 2017

본 소논문은 자크 데리다의 법과 윤리에 대한 철학들을 바탕으로 정부 검열 시스템에 담긴 한국 영화 정책을 연구하는 데에 목적이 있다. 군사독재 시대 이후 우리나라의 영화 정책은 독재 정권의 프로파간디를 널리 알리고, 사회 통합과 안정을 내세우며 국가적 목표에 부합한 작품을 보호하는 데에 중점을 맞춰왔다. 그리하여 모든 영화 관련 정책은 정부의 엄격한 통제와 감시 안에 존재했다. 그러한 정책은 단순히 영화 선택의 자유만을 제한하는 것이 아니라 창작의 영역까지 침범한다. 자크 데리다는 정의와 폭력과 법에 대한 여러 가지 문제제기를 해왔다. 데리다의 주장들은 윤리적 고찰과 연결되어 있다. 이 소노문은 데리다의 관점에서 한국 정부의 영화 검열 정책에 담긴 폭력성을 짚어보고 윤리적 검열정책의 가능성에 대해 고찰해보고자 한다.

• Structural Engineering and Mechanics
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• 제40권6호
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• pp.847-866
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• 2011

The objective of this study was to experimentally investigate the bond-related tension stiffening behavior of flexural reinforced concrete (RC) beams made with lightweight aggregate concrete (LWAC) under various high-cycle fatigue loading conditions. Based on strain measurements of tensile steel in the RC beams, fatigue-induced degradation of tension stiffening effects was evaluated and was, compared to reinforced normal weight concrete (NWC) beams with equal concrete compressive strengths (40 MPa). According to applied load-mean steel strain relationships, the mean steel strain that developed under loading cycles was divided into elastic and plastic strain components. The experimental results showed that, in the high-cycle fatigue regime, the tension stiffening behavior of LWAC beams was different from that of NWC beams; LWAC beams had a lesser reduction in tension stiffening due to a better bond between steel and concrete. This was reflected in the stability of the elastic mean steel strains and in the higher degree of local plasticity that developed at the primary flexural cracks.

• 한국환경복원기술학회지
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• 제12권3호
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• pp.83-97
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• 2009

The objects of study is to propose criteria for physical river disturbance assessment and as case study to show the application results for river improvement. For this purpose, the river disturbance assessment method for past disturbance process and the present-day potential natural state of stream is proposed. To assess the disturbance of the Youngcheon River caused by river improvement, One ares of Nam River was selected for the reference reach and two areas of Youngcheon River were selected for the comparison reach. And these reaches were surveyed and analyzed according to applying criteria of the river disturbances assessment. The assessment indices were physical factors as like epifaunal (bottom), embededness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection and riparian zone etc. The results showed that physical river environment in Youngcheon River area was disturbed by artificial revetment and bed excavation, consequently this disturbance give rise to impact of ecosystem in river. Hereafter, the criteria for river disturbance assessment are needed to consider various river characters as bed materials and bed slop etc.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.45-46
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• 2013

Stabilization characteristics of highly $N_2$-diluted $CH_4-O_2$ flame in an axially two-section porous inert medium were experimentally investigated for its application to the waste gas scrubber in semiconductor manufacturing processes. The flame behaviors were observed with respect to the fuel and $N_2$ flow rates and the equivalence ratios. As a result, four kinds of flame behaviors such as stable, flashback crossing the interface, blowout and sudden extinction were observed. It was also found that there exists two flame regime divided by a critical fuel flow rate. In addition, the flame stability was discussed based on the $N_2$ index which means the abatement capacity of our combustor in scrubbing the waste gas from the semiconductor processes.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1231-1240
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• 2019

Unlike land-based nuclear power plants, a marine or floating reactor is affected by external forces due to ocean conditions. These external forces can cause additional accelerations and affect each system and equipment of the marine reactor. Therefore, in designing a marine reactor and evaluating its performance and stability, a thermal hydraulic safety analysis code is necessary to consider the thermal hydrodynamic effects of ship motion. MARS, which is a reactor system analysis code, includes a dynamic motion model that can simulate the thermal-hydraulic phenomena under three-dimensional motion by calculating the body force term included in the momentum equation. In this study, it was verified that the dynamic motion model can simulate fluid motion with reasonable accuracy using conceptual problems. In addition, two modifications were made to the dynamic motion model; first, a user-supplied table to simulate a realistic ship motion was implemented, and second, the flow regime map determination algorithm was improved by calculating the volume inclination information at every time step if the dynamic motion model was activated. With these modifications, MARS could simulate the thermal-hydraulic phenomena under ocean motion more realistically.

• The Journal of Asian Finance, Economics and Business
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• 제9권8호
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• pp.7-17
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• 2022

The article discusses the problems caused by inflation in the developing Asia-Pacific region during the time of the worldwide pandemic and suggests innovative solutions to the problem. The reality is that some of the commodity groups from the consumer basket (e.g., non-seasonal fruits, electronics, furniture, hotel, and restaurant services, etc.) fail to reflect the needs of the low-income earners, which make the majority in developing countries. At the same time, the inflation targeting regime has become outdated and not reliable, because of uncontrolled exogenic factors (imported inflation, fluctuation in oil prices, supply chain disruption, Russia-Ukraine war, etc.) prevailing on endogenic factors and thus making it impossible to control the price stability, especially in developing countries. Since, the old-fashioned inflation index and inflation targeting mechanisms regrettably fail to fully reflect both the society and governmental/central banks' expectations, based on which we first should have better care and second create better policies; we propose to use a combination of already well-known indexes and policies, with the new statistical indicators, which reflects price fluctuations on the medication, utilities, and nutrition.

• 방사성폐기물학회지
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• 제20권4호
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• pp.429-453
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• 2022

Numerical modeling and scenario composition are needed to characterize the geological environment of the disposal site and analyze the long-term evolution of natural barriers. In this study, processes and features of the hydro-mechanical behavior of natural barriers were categorized and represented using the interrelation matrix proposed by SKB and Posiva. A hydro-mechanical coupled model was evaluated for analyzing stress field changes and fracture zone re-activation. The processes corresponding to long-term evolution and the hydro-mechanical mechanisms that may accompany critical processes were identified. Consequently, practical numerical methods could be considered for these geological engineering issues. A case study using a numerical method for the stability analysis of an underground disposal system was performed. Critical stress distribution regime problems were analyzed numerically by considering the strata's movement. Another case focused on the equivalent continuum domain composition under the upscaling process in fractured rocks. Numerical methods and case studies were reviewed, confirming that an appropriate and optimized modeling technique is essential for studying the stress state and geological history of the Korean Peninsula. Considering the environments of potential disposal sites in Korea, selecting the optimal application method that effectively simulates fractured rocks should be prioritized.