• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.34-43
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• 1993

In this paper, the characteristics of cable logging operations are discussed from a standpoint of mechanics. An example of standing skyline operations is used to illustrate the mechanical principles. Using force and moment boundary conditions, the maximum allowable payload was formulated as a function of slope profile, system geometry and operation options. This formulation includes fundamental equations for log drag and single segment mechanics. The catenary link model is the basic assumption in simulating cable segment stretches. In order to demonstrate the solution procedures of the formulation, a computer model was developed. The model uses Secant algorithm to determine the solution of the complex nonlinear equation set. Finally, the computer model was demonstrated using a hypothetical data set.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.315-318
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• 2011

본 논문에서는 구조물 연결부의 실시간 손상 검색을 통해 이상이 감지되었을 경우 자가치유까지 가능한 지능형 볼트접합부 시스템에 관한 실험적 연구결과가 제시되었다. 지능형 센서인 PZT센서의 전기-역학적 커플링 특성을 이용한 전기역학적 임피던스 기반의 구조물 건전성 평가 방법이 사용되었다. 전기역학적 임피던스의 측정을 통한 계측값을 베이스라인 값과 비교하는 손상 평가를 통해 구조물 볼트접합부의 볼트풀림 손상을 진단하고, 손상은 손상지수 RMSD를 통하여 정량화되었다. 볼트접합부의 손상이 감지되었을 경우 형상기억합금(SMA) 와셔에 부착되어있는 히팅 필름에 전원을 가함으로써 형상기억합금에 열을 가하고, 가열된 형상기억합금 와셔는 축방향으로 팽창을 함으로써 잃었던 볼트의 토크력을 회복시켜주었다. 실험 결과, 제안된 전기역학적 임피던스 기반의 구조물 건전성 평가기법과 형상기억합금 와셔 기반의 볼트접합부 자가치유 시스템의 성능 평가와 검증이 이루어졌다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.281-294
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• 2012

The current status of the computer codes for the analysis of coupled thermal-hydrological-mechanical behavior occurred in a high-level waste repository was investigated. Based on the reported results on the comparison between the predictions using the computer codes and the experimental data from the in-situ tests, the reliability of the existing computer codes was analyzed. The presented codes simulated considerably well the coupled thermal-hydrological-mechanical behavior in the near-field rock of the repository without buffer, but the predictions for the engineered barrier system of the repository located at saturated hard rock were not satisfactory. To apply the current thermal-hydrological-mechanical models to the assessment of the performance of engineered barrier system, a major improvement on the mathematical models which analyze the distribution of water content and total pressure in the buffer is required.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.184-193
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• 1998

In order to dispose radioactive wastes safely, it is needed to understand the mechanical, thermal, fluid behavior of rockmass and physico-chemical interactions between rockmass and water. Also, the knowledge about mechanical and hydraulic properties of rocks is required to predict and to model many conditions of geological structure, underground in-situ stress, folding, hot water interaction, intrusion of magma, plate tectonics etc. This study is based on researches about rock mechanics issues associated with a waste disposal in deep rockmass. This paper includes the mechanical and hydraulic behavior of rocks in varying temperature conditions, thermo-hydro-mechanical coupling analysis in rock mass and deformation behavior of discontinuous rocks. The mechanical properties were measured with Interaken rock mechanics testing systems and hydraulic properties were measured with transient pulse permeability measuring systems. In all results, rock properties were sensitive to temperature variation.

• Journal of the KSME
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• v.51 no.11
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• pp.28-31
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• 2011

고압 수소 시스템의 설계나 건전성 평가를 하려면 그 재료에 대한 수고의 환경에서의 역학적 특성을 알고 있어야 한다. 이글에서는 고압 수소 환경에서 재료의 역학적 특성 방법에 대해 소개하고자 한다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.197-207
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• 2006

The engineering performance of a high level waste repository is significantly dependent upon the T-H-M behavior in the engineered barrier system. An engineering-scale test facility (KENTEX) was set up to validate the T-H-M behaviors in the buffer of a reference disposal system developed in the 2002. The validation tests started on May 31, 2005 and is now in progress. The KENTEX facility and validation test programme are introduced, and pre-operation calculations are also presented to give information on the sensitive location of sensors and operational conditions. This test will provide information (e.g., large-scale apparatus, sensors, monitoring system etc.) needed for 'in-situ' tests, make the validation of a T-H-M model for the T-H-M performance assessment of the reference disposal system, and demonstrate the engineering feasibility of fabricating and emplacing the buffer of a repository.

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.133-142
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• 2019

In physics-based character animation, trajectory optimization has been widely adopted for automatic motion synthesis, through the prediction of an optimal sequence of future states of the character based on its system dynamics model. In general, the system dynamics model is neither in a closed form nor differentiable when it handles the contact dynamics between a character and the environment with rigid body collisions. Employing smoothed contact dynamics, researchers have suggested efficient trajectory optimization techniques based on numerical differentiation of the resulting system dynamics. However, the numerical derivative of the system dynamics model could be inaccurate unlike its analytical counterpart, which may affect the stability of trajectory optimization. In this paper, we propose a novel method to derive the closed-form derivative for the system dynamics by properly approximating the contact model. Based on the resulting derivatives of the system dynamics model, we also present a model predictive control (MPC)-based motion synthesis framework to robustly control the motion of a biped character according to on-line user input without any example motion data.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.05a
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• pp.18-29
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• 1999

다양한 환경의 변화에 따라 스포츠가 매스미디어에 의해 그 범위가 확산되면서 광고와 마케팅에 커다란 영향력을 발휘하는 현상을 보이고 있으며 스포츠마케팅과 매스미디어는 불가분의 관계에 놓여있다. 그러나 스포츠 마케팅에 있어서 매스미디어가 중요한 역할을 하고 있다고들 하나 그 역학관계에 대한 연구는 매우 저조한 상황이다. 따라서 본 연구는 스포츠 마케팅과 매스미디어와의 역학구조를 단계적으로 살펴보고 시스템 다이내믹스 개념을 이용하여 역학구조 내에서 영향을 연구하여 향후의 스포츠마케팅 연구 및 실행에 있어 매스미디어와의 관계연구에 방향을 제시하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.235-235
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• 2010

풍력발전기의 공기역학적 비선형성은 풍력발전기 전체 시스템의 동적특성에 영향을 미친다. 풍력발전기의 드라이버-트레인의 감쇠가 매우 작으므로 풍력발전기를 제어함에 있어 드라이버-트레인의 동적특성은 중요하게 고려되어야 한다. 본 논문에서는 풍속에 따른 공기역학적 비선형성이 드라이버-트레인의 동적특성에 미치는 영향을 해석적으로 살펴보고자 한다.

• Nuclear industry
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• v.27 no.3 s.289
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• pp.62-68
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• 2007