• Tribology and Lubricants
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• v.6 no.1
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• pp.89-98
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• 1990

시일의 접촉면이 경사지고, 정현파형이 존재하며 코닝이 있는 경우에 대한 해석을 하였다. 또한 시일링 간극에 존재하는 유체는 비압축성 점성유체이다. 이러한 요소들을 고려한 레이놀즈 방정식의 일반해를 구하기 위하여 멱급수 근사이론을 이용하여 압력분포를 구하였고, 이 결과를 이용하여 시일의 누설 유동량 및 마찰 토오크를 해석하였다. 계산 결과에 의하면 시일 접촉면의 표면파형이나 코닝에 비하여 경사정도가 시일의 성능에 커다란 영향을 주고 있음을 보여주고 있다.

• Annual Conference on Human and Language Technology
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• 1990.11a
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• pp.199-199
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• 1990

입력된 문서 영상으로부터 분리 추출된 문자 영상을 올바르게 인식하는 것은 문서 인식에서 가장 핵심적인 부분이다. 스캐너를 통해 입력되고 분리된 실제의 문자 영상은 많은 문제점들을 가지고 있다. 한글의 경우 이 중 개별 문자 영상내의 각 자소간의 접촉은 올바른 인식을 저해하는 주요한 원인이다. 이런 접촉의 문제를 효율적으로 해결하기 위해 한글의 구조적 특성을 지닌 "방향 필터"를 정의하고, 이것을 이용하여 세선화된 문자 영상을 추적하면서 선소들을 뽑아낸다. 이렇게 하여 얻은 선소들과 선소들간의 지식을 조합하여 한글자소 획을 추출케 되고 결국에는 이런 획의 조합을 통해 문자 영상을 인식하는 방법을 제안한다.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1976-1977
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• 2003

3차원 영상저장과 복원에 이용되어왔던 변형 삼각간섭계를 이용하여 비접촉진단에의 응용가능성을 연구한다. 변형 삼각간섭계를 이용하여 측정대상물체의 간섭패턴을 3-5개 구하고 이로부터 위상지도를 얻고 이로부터 변형량을 계산할 수 있다는 것을 이론적으로 제시한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.249-263
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• 2017

The expansion behavior of inflatable steel pipe rockbolt shows geometric nonlinearity due to its ${\Omega}-shaped$ section. Previous studies on the anchoring behavior of inflatable steel pipe rockbolt were mainly performed using theoretical method. However, those studies oversimplified the actual behavior by assuming isotropic expansion of inflatable steel pipe rockbolt. In this study, the anchoring behavior of the inflatable steel pipe rockbolt were investigated by the numerical method considering the irregularity of pipe expansion and other influencing factors. The expansion of inflatable steel pipe rockbolt, the contact stress distribution and the change of the average contact stress and the contact area during installation were analyzed. The contact stresses were developed differently depending on the constitutive behavior of rocks. Small contact stresses occurred in steel pipes installed in elasto-plastic rock compared to steel pipes installed in elastic rock. Also, the anchoring behaviors of the inflatable steel pipe rockbolt were different according to the stiffness of the rock. The steel pipe was completely unfolded in the case of the stiffness smaller than 0.5 GPa, but it was not fully unfolded in the case of the stiffness larger than 0.5 GPa for the given analysis condition. When the steel pipe is completely unfolded, the contact stress increases as the rock stiffness increases. However, the contact stress decreases as the rock stiffness increases when the steel pipe is not fully expanded.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.44-56
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• 1993

The purpose of this paper is to analyze the impact response behaviors of glass/epoxy laminated composite plates subjected to the transversely impact of a steel ball. For this purpose, dynamic finite element analysis based on the higher-order shear defomation plate theory is used to compute the contact forces, rebound velocity of a steel ball, and dynamic strain response histories. And low-velocity and high-velocity impact experiments were conducted to compare the results and compute the wave propagation velocities. The results obtained from impact experiments are in good agreement with those of dynamic finite element analysis. Also the wave propagation velocities obtained from high-velocity impact experiments and wave propagation theory agree well, and wave velocities were higher in the smaller radius of steel ball.

• Membrane Journal
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• v.21 no.3
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• pp.236-246
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• 2011

In this study, we used prepared a cylindrical module consisting 100 hollow fibers of commercialized (hydrophobic) polyethylene membrane of $0.4{\mu}m$ pore size and systematically studied performance of direct contact membrane distillation (DCMD) and sweep gas membrane distillation (SGMD) in terms of variation of permeate flux and salt rejection with respect to temperature drop across the membrane, salt concentrations in feed, and flow rates of cooling water and sweep gas. SGMD was regarded as DCMD with a sweep gas layer between permeate-side membrane surface and cooling water. Sweep gas flow decreases the permeate flux from that of DCMD by providing an additional gas-layer resistance. We compared DCMD and SGMD performance by using mass balance with a fitting parameter (${\omega}$), indicating fraction of permeate flow rate.

• Bulletin of the Society of Naval Architects of Korea
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• v.11 no.1
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• pp.35-44
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• 1974

열박음(shrink fitting)으로 인(因)한 동심형(同心形) 구멍을 가진 복합(複合)실린더의 과도적(過渡的) 온도분포(溫度分布), 열응력(熱應力) 및 열변형도(熱變形度)를 이론해석(理論解析)하였다. 온도분포해석(溫度分布解析)에서 외부(外部) 실린더는 균일온도(均一溫度)로 가열(加熱)되어, 실온(室溫)의 내부(內部) 실린더와 접촉면(接觸面)에서 일어나는 열전도(熱傳導)에 의(依)하여 냉각(冷却)되고, 외부(外部) 표면(表面)은 대기중(大氣中)에 노출(露出)된 상태(狀態)로 취급(取扱)하였다. 열응력(熱應力)은 평면변형도조건(平面變形度條件)을 만족(滿足)하는 것으로 생각하였으며, 물성(物性)은 온도(溫度)에 무관(無關)한 상수(常數)로 취급(取扱)하였다. 온도분포(溫度分布)는 열전도문제(熱傳導問題)만을 고려(考慮)함으로서도 유효(有效)한 해(解)를 얻을 수 있으며 열응력(熱應力)은 접촉면(接觸面)에서부터 형성(形成)되며, 반경방향응력(半徑方向應力)은 시간(時間)이 경과(經過)함에 따라 압축응력(壓縮應力)이 증가(增加)하여 접촉면(接觸面)에서 최대치(最大値)를 갖고, 원주방향응력(圓周方向應力)은 접촉면(接觸面)에서 초기(初期)부터 거의 최종상태(最終狀態)와 같은 크기를 갖음을 알 수 있다. 균일온도분포(均一溫度分布)가 이루어지면 열응력(熱應力)의 형성(形成)은 완료(完了)되게 되며, 이때의 열응력(熱應力)의 크기와 분포경향(分布傾向)은 평면응력조건(平面應力條件)을 사용(使用)하였다는 사실(事實)을 고려(考慮)하면 $Lam\acute{e}$의 이론해(理論解)와 일치(一致)함을 알 수 있었다.

• Informatization Policy
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• v.22 no.4
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• pp.91-104
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• 2015

This study tests the effects of differential association, definitions, differential reinforcement and imitation from social learning theory in the explanation of university students' crimes in social network services. In addition, this study tests the interaction effects between social learning factors and other factors such as low self-control, subcultural environment, and crime opportunity for the integrated approach. Using data from 486 university students in Seoul, results show that both definition and imitation have significant influences on crimes, even though differential association and differential reinforcement factors have no significant influences on crimes in social network services. Results also reveal that there are significant interaction effects between definition and subcultural environment, which meana that definition has a strong effect on crimes in high subcultural environment. In addition, it is found that reinforcement has also a strong effect on crimes in high crime opportunity and that interaction effect between imitation and low self-control is significant, which means that imitation has a strong effect on crimes in low self-control students.

• Korean Journal of Materials Research
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• v.3 no.1
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• pp.58-64
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• 1993

The degree of work hardening in the subsurface zones varied with the experimental conditions under the rolling contact fatigue wear test of high carbon Cr-Ti alloy steel was evaluated by the distribution of residual stresses. Surface residual stresses before the test did not affect the wear property. Surface residual stresses after the test decreased by the increase of contact stress and running. velocity. but the maximum compressive residual stress and its depth of saturation in the subsurface zone increased. The relationship between these experimental results and the distribution of the theoritical shear stress was also discussed.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.163-172
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• 2000

The EB type contact binaries show large temperature difference $(\mid\bigtriangleup T\mid\geq1,000K)$ between two components. Thus we have modified the mode 3 of the WD program to adjust albedos, limb darkening coefficients and gravity darkening exponents for both components of such binaries, while the values for those parameters should be same for both components in the original WD program. Both of the modified and the original versions have been applied to the EB type contact binaries such as DO Cas, GO Cyg, and FS Lup. The computed light curves with modified version fit better to the observations.