• Title/Summary/Keyword: University Section

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A Study on Development of Sway Velocity Reference Model During Auto-berthing/Unberthing Through Analysis of Ship's Berthing/Unberthing Data (선박의 이/접안 데이터 분석을 통한 자동 이/접안 시 횡방향속도 참조모형 개발에 관한 연구)

  • Kim, Jung-Hyeon;Jo, Hyun-Jae;Kim, Su-Rim;Lee, Jun-Ho;Park, Jong-Yong
    • Journal of the Society of Naval Architects of Korea
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    • v.58 no.6
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    • pp.358-365
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    • 2021
  • Crabbing motion is a pure sway motion with only sway velocity. The ship's crabbing motion is essential for an ideal berthing/unberthing process. The unberthing situation proceeds in sequential order such as crabbing motion section, pivoting section, and outer port section. For the berthing situation, the sequence has a reverse order: the inner port section, pivoting section, and crabbing motion section. In this paper, the berthing/unberthing data of the reference ship, Pukyong National University research ship "NARA", was analyzed to develop a sway velocity reference model. Several constraints were defined to derive the crabbing motion section during berthing/unberthing. The sway velocity reference model for the auto-berthing/unberthing was developed using the estimated sway velocity. A reproduction simulation of the ship was performed to compare the designed reference model and the reference ship data.

An Experimental Study on the Axial Collapse Characteristics of Hat and Double Hat Shaped Section Members at Various Velocities

  • Cha, Cheon-Seok;Chung, Jin-Oh;Yang, In-Young
    • Journal of Mechanical Science and Technology
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    • v.18 no.6
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    • pp.924-932
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    • 2004
  • In this study, the axial collapse tests were performed under either static (or quasi-static) or impact loads with several collapse velocities based on the expectation that para-closed sections of the front-end side members (spot welded hat and double hat shaped section members) would show quite different collapse characteristics from those for seamless section. The test results showed that both of the hat and double hat shaped section members failed in the stable sequential collapse mode in the static or quasi-static collapse tests, while the double hat shaped section members underwent the unstable collapse mode especially when the impact velocity is high. The mean collapse loads in the hat shaped section members increase with collapse velocity for all the cases of the static, quasi-static, and impact collapse tests. In the double hat shaped section members, however, the mean collapse loads decrease with increase in collapse velocity in the impact tests.

응력-침투 연계 해석에 의한 필 댐의 최적 설계

  • Park, Chun-Sik;Lee, Jun-Suk;Kim, Jong-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.862-870
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    • 2010
  • This thesis has been researched on optimized design method for the total cross section of embankment considering the fact that the size of embankment cross section is directly related with economic efficiency when dam designing. In general, embankment cross section of fill dam is either determined by cohesion and angle of internal friction, a strength parameter of embankment materials or by permeability of embankment. Therefore the size of embankment cross section depending on strength parameter of embankment materials was determined by using MIDAS-GTS program through stress-seepage coupled analysis at the time of fill dam design. As a result, determination of embankment cross section was more affected by the size of central core and permeability rather than by slope stability by shear strength and it was revealed that in case of embankment height being over 20m, stability against infiltration and slope action could be secured only when embankment slope is at least over 1:2.5. In addition, it was also revealed that in case of making the size of central core exceeding specification standard, total cross section of embankment could be reduced considerably and at the time of embankment design, adequate size and appropriateness of embankment cross section could be determined with referring the table suggested by this study.

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Mach-Zehnder Type $Ti:LiNbO_3$ Traveling-Wave Optical Modulator with m-Section Phase Reversal (m-section의 위상반전이 있는 Mach-Zehnder형 진행파 $Ti:LiNbO_3$ 광변조기)

  • Lee, Woo-Jin;Kim, Kyoung-Am;Kim, Woo-Kyung;Kim, Chang-Min
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.39 no.7
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    • pp.26-36
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    • 2002
  • Mach-Zehnder type traveling-wave optical modulators with 3-section and 5-section phase reversal were designed and fabricated on z-cut $LiNbO_3$ substrates. Optical waveguides were designed by means of the FDM(Finite Difference Method). Design of CPW traveling-wave electrodes were performed by the SOR(Successive Over Relaxation) in the active region and by the CMM(Conformal Mapping) in the input/output section. The optical response R(${\omega}$ calculated based on the measured S-parameters showed the bandwidth of 15GHz centered at 25GHz for the 3-section, and the bandwidth of 22GHz at 45GHz for the 5-section.

Analysis of Self-Pulsation Characteristics in Multi-Section Complex-Coupled DFB Lasers With Amplifying Optical Feedback (증폭된 광 귀환을 가자는 다중 전극 복소 결합 DFB 레이저에서 발생되는 self-pulsation 특성 해석)

  • Kim, Sang-Taek;Kim, Tae-Young;Kim, Boo-Gyoun;Leem, Young-Ahn;Park, Kyung-Hyun
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.527-534
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    • 2005
  • We investigate the pulsation characteristics in a multi-section DFB laser which is composed of one DFB section, phase tuning section, and gain section. Multi-section DFB lasers with anti-phase (AP) complex-coupled (CC) DFB structure show wide current ranges of gain and phase tuning sections fer stable pulsations compared to those with in-phase CC DFB structure or index-coupled DFB structure. For multi-section DFB lasers with AP CC DFB structure, the current range of a gain section for stable pulsations increases and the tuning range of the pulsation frequency increases as a coupling strength or a gain coupling coefficient increases Also, the tuning range using the phase variation in a phase tuning section increases. For a fixed coupling strength, the current ranges of gain and phase tuning sections for stable pulsations increase and the tuning range of the pulsation frequency increases as the length of a DFB section increases.

Prediction of the Rupture of Circular Sections of Reinforced Concrete and Fiber Reinforced Concrete

  • Adjrad, A.;Bouafia, Y.;Kachi, M.S.;Ghazi, F.
    • International Journal of Concrete Structures and Materials
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    • v.10 no.3
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    • pp.373-381
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    • 2016
  • As part of this study, has been developed a numerical method which allows to establish abacuses connecting the normal force with bending moment for a circular section and therefore to predict the rupture of this type of section. This may be for reinforced concrete (traditional steel) or concrete reinforced with steel fibers. The numerical simulation was performed in nonlinear elasticity up to exhaustion of the bearing capacity of the section. The rupture modes considered occur by plasticization of the steel or rupture of the concrete (under compressive stresses or tensile stresses). Regarding the fiber-reinforced concrete, the rupture occurs, usually, by tearing of the fibers. The behavior laws of the different materials (concrete and steel) correspond to the real behavior. The influence of several parameters was investigated, namely; diameter of the section, concrete strength, type of steel, percentage of reinforcement and contribution of concrete in tension between two successive cracks of bending. A comparison was made with the behavior of a section considering the conventional diagrams of materials; provided by the BAEL rules. A second comparative study was performed for fibers reinforced section.