• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.381-385
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• 1996

본 연구에서는 자동화 제조 시스템 (Automatic Manufacturing System :AMS)의 설계및 구현에 있어서 물리적인 검증 (Physical Validation)을 위한 소프트웨어 시스템의 구조를 제안하고 구현하였다. 제안된 소프트웨어 시스템은 설비들과 물류 흐름에 있어서 간섭 검증과 운영 가능성을 검증하는 기능을 제공하며 크게 4개의 모듈로 나누어져 있다. : 1) 기본 형상들을 이용하여 원하는 형상을 정의하는 "Shape Modeling Module", 2) 실제 설비의 Kinematics와 기능을 모델링하는 "Facility Modeling Module", 3) AMS의 물리적인 배치를 구성하는 "Layout Design Module", 4) 모델링된 AMS를 실행시켜 볼 수 있는 "Factory Emulation Module". 이와 같은 소프트웨어 시스템을 구현하기 위해 수행된 주된 연구는 다음과 같다. : 1) AMS를 구성하는 설비들을 모델링하는 방법을 제시, 2) 표준 설비들의 Instancing Parameter 제시, 3) C++과 GL을 이용하여 소프트웨어로의 구현, 4) Flexible Manufacturing System (FMS)에의 응용.lexible Manufacturing System (FMS)에의 응용.

• Coupled systems mechanics
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• v.5 no.1
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• pp.59-86
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• 2016

This paper deals with the free vibration analysis of a dynamical coupled system: flexible gravity dam- compressible rectangular reservoir. The finite element method is used to compute the natural frequencies and modal shapes of the system. Firstly, the reservoir and subsequently the dam is modeled by classical 8-node elements and the natural frequencies plus modal shapes are calculated. Afterwards, a new 21-node element is introduced and the same procedure is conducted in which an efficient method is employed to carry out the integration operations. Finally, the coupled dam-reservoir system is modeled by solely one 21-node element and the free vibration of dam-reservoir interaction system is investigated. As an important result, it is clearly concluded that the one high-order element treats more precisely than the eight-node elements, since the first one utilizes fifth-degree polynomials to construct the shape functions and the second implements polynomials of degree two.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.109-109
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• 2006

Flexible polymers with densely grafted side chains adopt the shape of cylindrical brushes, because the steric repulsion of the side chains overcomes the entropic restoring force of the main chain. Combined light-and neutron scattering measurements elucidate the extend of main chain and side chain stretching as function of side chain length. The application of cylindrical brushes as molecular actuators in response to external stimuli which is discussed.

• Steel and Composite Structures
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• v.2 no.5
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• pp.315-330
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• 2002

This paper proposes a model for analysing the non-linear behaviour of steel concrete composite beams prestressed by external slipping cables, taking into account the deformability of the interface shear connection. By assuming a suitable admissible displacement field for the composite beam, the balance condition is obtained by the virtual work principle. The solution is numerically achieved by approximating the unknown displacement functions as series of shape functions according to the Ritz method. The model is applied to real cases by showing the consequences of different connection levels between the concrete slab and the steel beam. Particular attention is focused on the limited ductility of the shear connection that may be the cause of premature failure of the composite girder.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.118-124
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• 1998

The die wear is one of the main factors affecting die accuracy and tool lifetime. It is desired to reduce die wear by developing simulation method to predict wear based on process variables, and then optimizing the process. Therefore, this paper describes methodology of preform design for minimizing wear of finisher die in multi-stage cold forging processes. The finite element method is combined with the routine of wear prediction. The cold forging process is analyzed using developed simulation method. In order to obtain preform to minimize die wear, the Flexible Polyhedron Search(FPS) algorithm is used. The optimal preform shape is found from iterative deformation analysis and wear calculation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.224-229
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• 1997

This paper compares the control techniques for position control experiments of a fixible robot moving in a vertical plane. The flexible manipulator is modeled as an Euler-beroulli beam. Elastic deformantion is representedusing the assumed model method. A comparison function which satisfies all geometric and natural boundary conditions of a cantilever beam with an end mass is used as an assumed mode shape. Lagrange's equation is utilized for the development of a discretized model. Control schemes are developed using PID control,pole placement control and discrete Linear Quadratic Regulater(LQQ). The effectiveness of the developed control schems are compared using computer simulation in view of practical experiment. The simulation results show that PID control is very effective in practical implementation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.77-80
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• 2001

The element-free Galerkin (EFG) method is one of meshless methods, which is an efficient method of modeling problems of fluid or solid mechanics with complex boundary shapes and large changes in boundary conditions. This paper discusses the theory of the EFG method and its applications to modeling of groundwater flow. In the EFG method, shape functions are constructed based on the moving least square (MLS) approximation, which requires only set of nodes. The EFG method can eliminate time-consuming mesh generation procedure with irregular shaped boundaries because it does not require any elements. The coupled EFG-FEM technique was introduced to treat Dirichlet boundary conditions. A computer code EFGG was developed and tested for the problems of steady-state and transient groundwater flow in homogeneous or heterogeneous aquifers. The accuracy of solutions by the EFG method was similar to that by the FEM. The EFG method has the advantages in convenient node generation and flexible boundary condition implementation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.17-20
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• 2008

This study investigated the fundamental properties and cracking shapes of mortar for the floor after Mock-up test with FRP as wastes of crafts. For the flowability of fresh mortar without FRP, it was favorable compared with fresh mortar using FRP, and the drop time at O-Lot was similar to the flowability. For the compressive strength of fresh mortar with FRP, it was increased about 10% compared with plain. The flexible strength was also increased on fresh mortar with FRP. On the cracking shape, there was many penetrated crack in all directions on plain. In the case that FRP was used, it seemed to have excellent resistance to the crack occurrence because there was no directive crack at a limited part.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.68-69
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• 2014

Production of freeform concrete segments use various molds because of the unique shape of it unlike common concrete segments. As a result, the mold for freeform concrete segments cannot be reused. Therefor, cost overrun is occurred by needs of more time and manpower to produce the freeform concrete segments compared with common concrete segments. To prevent the cost overrun, a new production method for the freeform concrete segments is needed to develop and the requirements for it should be analyzed before. Therefor, the aim of this study is requirements analysis for production of freeform concrete segment. The requirements of production of freeform concrete segments and form for it is analyzed in this study. The result of this study would be used to suggest the new production method of freeform concrete segments.

• 전기의세계
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• v.44 no.6
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• pp.27-36
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• 1995

인구증가와 경제성장 및 문화발전에 수반하여 전력수요는 증가되고 사용시간과 장소가 집중되는 경향이다. 따라서 계절별, 일형별, 시간별, 지역별로 부하차이가 심해지고 부하율이 저하한다. 종래와 같이 예측되는 전력수요 곡선을 왜곡(distortion)시키지 않고 그대로 충족시킬 수 있는 설비를 계획하고 건설하여 운용하는 공급관리(SSM:Supply Side Management)에 의존할 때는 설비증설과 투자비가 증가하고 설비이용율이 저하하며 운전유지비가 증가하여 전력단가가 높아진다. 뿐만 아니라 지구환경을 해롭게 하는 CO$_{2}$ 배출량이 증가한다. 이러한 실저에서 설비투자비와 운전유지비를 절감하고 환경보전을 하기 위하여 수요곡선의 모양을 개선하도록 유도할 필요가 있다. 최근 세계적 추세는 부하관리와 효율향상 등으로 수요곡선 모양을 개선하는 수요관리(DSM:Demand-Side Management)에 치중하고 있다. 여기서는 전력수요고나리의 효과적 방법으로서 이른바 원격부하제어(RLC: Remote Load Control), 일명 직접부하제어(Direct Load Control)시스템으 개발기술을 검토한다. 개발코자 하는 RLC시스템은 일시정지시켜도 지장이 적은 수용가의 부하를 주기적으로 공급자가 제어할 수 있도록 하여 가변부하조성(Flexible Load Shape)을 하는 것이다. 가변부하조성은 필요시 운전예비율을 공급자와 수요자가 분담함으로서 전력수급의 안정을 도모하고 사회적 공급 지장비용을 경감시킬 수 있다.