• Geomechanics and Engineering
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• v.35 no.1
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• pp.55-65
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• 2023

Soft clay is widely spread in nature and encountered in geotechnical engineering applications. The creep property of soft clay greatly affects the long-term performance of its upper structures. Therefore, it is vital to establish a reasonable and practical creep constitutive model. In the study, two updated hyperbolic equations based on the volumetric creep and deviatoric creep are respectively proposed. Subsequently, three creep constitutive models based on different creep behavior, i.e., V-model (use volumetric creep equation), D-model (use deviatoric creep equation) and VD-model (use both volumetric and deviatoric creep equations) are developed and compared. From the aspect of prediction accuracy, both V-model and D-model show good agreements with experimental results, while the predictions of the VD-model are smaller than the experimental results. In terms of the parametric sensitivity, D-model and VD-model are lower sensitive to parameter M (the slope of the critical state line) than V-model. Therefore, the D-model which is developed by incorporating the updated deviatoric creep equation is suggested in engineering applications.

• Journal of the Korean Society for Railway
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• v.11 no.1
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• pp.7-12
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• 2008

An experimental study has been conducted to investigate the effect of tunnel slope on critical velocity by using the model funnel of the 1/20 reduced-scale applying the Floods scaling law. the square liquid pool burners were used for methanol, acetone and n-heptane fires. tunnel. Tunnel slopes varied as five different degrees $0^{\circ}$, $2^{\circ}$, $4^{\circ}$, $6^{\circ}$ and $8^{\circ}$. The mass loss rate and the temperatures are measured by a load celt and K-type thermocouples for tunnel slope. Present study results in bigger the critical velocity than the research of Atikinson and Wu using the propane burner. Therefore, when estimating the critical velocity in slope tunnel, the variations of the heat release rate is an important factor. The reason is the ventilation velocity directly affects variation of heat release rate when slope tunnel fire occurred.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.36-40
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• 2003

The considered satellite is supposed to operate in the earth-point mode and sun-point mode in accordance with the mission requirements. The magnetic field correction is based on the orbit geometry using a set of measured magnetic field data from the three-axis-magnetometer and its algorithm excludes the earth’s magnetic field model. Moreover, the usefulness of the proposed method is investigated throughout the simulation of KOMPSAT-1.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.677-678
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• 2005

• The Korean Journal of Financial Studies
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• v.14 no.1
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• pp.1-14
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• 2008

본 논문은 외환시장의 효율성과 노이즈 트레이더 모델에 관해 고찰하며, 별도의 실증분석을 수행하지는 않지만 비효율적인 외환시장에서 통화의 가격결정 메커니즘에 대해 노이즈 트레이더 모형의 적용가능성을 분석함으로써 향후 연구방향을 제시하고자 한다. 본 논문과 관련해 의미 있는 또 하나의 연구방향으로는 외환시장에서 정부의 역할이 있다. 정부가 특정한 수준으로 통화를 유지하거나, 정책 목적을 위해 통화를 특정한 수준으로 변경시키기 위한 노력의 일환으로 외환시장에 자주 개입하는 것은 분명하다. 이러한 정부의 역할은 그 자체로는 분명히 노이즈 트레이딩이 아니지만, 외환시장에 대한 영향으로 보면 노이즈 트레이딩과 크게 다르지 않을 것이다. 합리적인 차익거래자, 노이즈 트레이더 및 중앙은행을 통합하는 모델을 개발하고 검증하는 것은 외환시장의 메커니즘을 이해하는데 많은 도움이 될 것이다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1003_1004
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• 2009

본 논문에서는, Matlab/Simulink를 사용하여 영구자석 동기전동기(PMSM)의 벡터제어 및 제어기설계에 대하여 기술하겠다. dq모델의 수학적 해석을 바탕으로 PMSM드라이브의 전류제어와 속도제어기에 Lag- controller를 사용하였다. Black block models과는 다른 시뮬레이션으로 모든 매개변수에 대해서 제어와 증명을 쉽게 할 수 있다. Matlab/Simulink로 로드 토크가 있는 PMSM을 증명하고 그 결과 값을 알아보았다.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.611-623
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• 2010

Excessive stay cable vibrations can cause severe problems for cable-stayed bridges. In this paper a semiactive Magnetorheological (MR) damper is investigated to reduce cable vibrations. The control-oriented cable-damper model is first established; a computer simulation for the cable-damper system is carried out; and finally a MR damper is experimentally used to reduce the cable vibration in a laboratory environment using a semiactive control algorithm. Both the simulation and experimental results show that the semiactive MR damper achieves better control results than the corresponding passive damper.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.157.2-157.2
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• 2008

• Bulletin of the Korean Mathematical Society
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• v.56 no.5
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• pp.1355-1376
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• 2019

We investigate the valuation of participating life insurance policies with default risk under a geometric regime-switching jump-diffusion process. We derive explicit formula for the Laplace transform of the price of participating contracts by solving integro-differential system and then price them by inverting Laplace transforms.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.2-3
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• 2015

This paper probes into safety leadership in construction and its impacts on site safety performance. A safety leadership model for construction is proposed. It contains two impacting paths of safety leadership, namely safety management and safety culture. By action research, safety improvement is achieved through leadership fulfillment on construction sites.