• Structural Engineering and Mechanics
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• 제87권4호
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• pp.363-373
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• 2023

Since the first family of structure-dependent methods can simultaneously integrate unconditional stability and explicit formulation in addition to second order accuracy, it is very computationally efficient for solving inertial problems except for adopting auto time-stepping techniques due to no nonlinear iterations. However, an unusual stability property is first found herein since its unconditional stability interval is drastically different for zero and nonzero damping. In fact, instability might occur for solving a damped stiffness hardening system while an accurate result can be obtained for the corresponding undamped stiffness hardening system. A technique of using a stability factor is applied to overcome this difficulty. It can be applied to magnify an unconditional stability interval. After introducing this stability factor, the formulation of this family of structure-dependent methods is changed accordingly and thus its numerical properties must be re-evaluated. In summary, a large stability factor can result in a large unconditional stability interval but also lead to a large relative period error. As a consequence, a stability factor must be appropriately chosen to have a desired unconditional stability interval in addition to an acceptable period distortion.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1324-1329
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• 2004

In this article we have tested stability of classifier based on fuzzy similarity in generalized Lukasiewicz structure. Two different tests for stability was made:In on test stability was checked respect to weight parameters and other test was carried out for idealvectors. Tests have made with three different classification problems.

• 제어로봇시스템학회논문지
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• 제11권6호
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• pp.492-495
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• 2005

This paper deals with the problem of estimating the asymptotic stability region(ASR) of uncertain variable structure systems with bounded control. Using linear matrix inequalities(LMIs) we estimate the ASR and we show the exponential stability of the closed-loop control system in the estimated ASR. We show that our estimate is always better than the estimate of [3].

• 한국안전학회지
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• 제14권1호
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• pp.33-40
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• 1999

In this paper, a damaged example of hanging guide frame used in the lifting of shore protection caisson was investigated. An examination of the stress and stability of members was carried out by structural analysis and the causes of damages was investigated. The stability analysis considering local and global stress buckling was performed. As a result of stability analysis. the first structure was unstable structure. Therefore improved structure was examined and the best effective methodology was the reassignment of wire.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.132-136
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• 2003

A Multi-Spectral Camera (MSC) is the payload of KOMPSAT-2 which is designed for earth imaging in visible and near-Infrared region on a sun-synchronous orbit. The telescope in the MSC is a Ritchey-Chretien type with large aperture. The telescope structure should be well stabilized and the optical alignment should be kept steady so that best images can be achieved. However, the MSC is exposed to adverse thermal environment on the orbit which can give impacts on optical performance. Metering structure which is exposed to adverse space environment should have tight requirement of low thermal expansion and hygroscopic stability. In order to meet those stability requirements in addition to fundamental structural ones telescope structure was designed with newly developed graphite-cyanate composite which has high tensile modulus, high thermal conductivity and low moisture absorption compared with conventional graphite-epoxy composite. In this paper, space-borne telescope structure with new composite material will be presented and fulfillment of stability requirements will be verified with designed structure.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1149-1155
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• 2004

In this paper, novel methods for improvement of thermal stability of Ni-germano Silicide were proposed for nano CMOS applications. It was shown that there happened agglomeration and abnormal oxidation in case of Ni-germano Silicide using Ni only structure. Therefore, 4 kinds of tri-layer structure, such as, Ti/Ni/TiN, Ni/Ti/TiN, Co/Ni/TiN and Ni/Co/TiN were proposed utilizing Co and Ti interlayer to improve thermal stability of Ni-germano Silicide. Ti/Ni/TiN structure showed the best improvement of thermal stability and suppression of abnormal oxidation although all kinds of structures showed improvement of sheet resistance. That is, Ti/Ni/TiN structure showed only 11 ohm/sq. in spite of 600 $^{\circ}C$, 30 min post silicidation annealing while Ni-only structure show 42 ohm/sq. Therefore, Ti/Ni/TiN structure is highly promising for nano-scale CMOS technology.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1987-1992
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• 2004

A Variable Structure Model Reference Adaptive Controller (VS-MRAC) using state Variables is proposed for single input multi output systems. . The structure of the switching functions is designed based on stability requirements, and global exponential stability is proved. Transient behavior is analyzed using sliding mode control and shows perfect model following at a finite time. The effect of input disturbances on stability and transients is investigated and shows preference to the conventional MRAC schemes with integral adaptation law. Sliding surfaces are independent of system parameters and therefore VS-MRAC is insensitive to system parameter variations. Simulation is presented to clear the theoretical results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1425-1429
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• 2003

In this study, when structure which is combined by welding is receiving internal pressure, finite element analysis to confirm stability of structure and reliability of welding part is achieved. And we analyze the results. Also, if stability of the structure and reliability of the welding part are not defined, research that look for method to change design to receive stability and reliability is achieved.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.94-102
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• 1999

The retaining wall is a structure which was made for changing land form in many construction. The first role of the retaining wall is to maintain the slope stability. But recently, the amount of retaining wall have been increasing because of the expansion of construction works and the amenity of urban environment have been decreasing because of environmental destruction and the scenic heterogeneity. So we should consider the slope stability and ecological stability at the same time. The purpose of this study is to develop the retaining wall revegetation technology using the Eco-Stone, the structure of co-satisfying which included the slope stability and the revegetation effect. Eco-Stone is a structure which has high stability for earth pressure, settlement and drainage. And cost and term of construction works also have been decreased. Eco-Stone structure is one of factors composing the ecological network which is harmonize with surrounding environment. In this way, it is expected that the ecological habitats of various species would be restored.

• 대한토목학회논문집
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• 제41권3호
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• pp.327-330
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• 2021

수처리 콘크리트 구조물과 건축 구조물 설계시 일반적으로 부력의 안정성 검토는 행해지고 있으나, 고정하중의 중심과 부력의 중심 사이의 편심으로 인한 부력모멘트에 대한 안정성 검토는 행해지지 않고 있다. 본 검토에서는 부력이 커짐에 따라 고정하중(W)과 부력(B)의 합력의 작용점과 반력분포를 고찰하여 부력모멘트 회전지점의 형성을 규명함으로써 수처리콘크리트구조물과 건축 구조물의 부력모멘트에 의한 회전부상 안전율식을 도출하여 부력모멘트에 대한 안정성 검토방법을 제시하였다.