• Journal of Ocean Engineering and Technology
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• v.13 no.2 s.32
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• pp.11-17
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• 1999

The objective of this paper is to introduce very fast but still stable solution using finite element procedures, and it has been used in an iterative mode for product design applications. A lot of numerical techniques have been developed to deal with the material, geometric and boundary condition non-linearities occurred in the stamping process. One of them, the One-Step FEM is very efficient and useful tool for a design and trouble-shooting in various stamping processes. In this method, the mathod, the material is assumed to deform directly from the initial flat blank to the final configuration without any intermediate steps. The formulation is based on the deformation theory of plasticity and the upper bound theorem. As a result of the calculations, the initial blank shape is obtained, together with the material flow, strains and thickness distribution in the part.

• Advances in nano research
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• v.8 no.2
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• pp.103-114
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• 2020

In this research, buckling and free vibration of rectangular polymeric laminate reinforced by graphene sheets are investigated. Various patterns are considered for augmentation of each laminate. Critical buckling load is evaluated for different parameters, including boundary conditions, reinforcement pattern, loading regime, and laminate geometric states. Furthermore, vibration analysis is investigated for square laminate. Elastic properties of the composite are calculated using a combination of both molecular dynamics (MD) and the rule of mixture (MR). Kinematics of the plate is approximated based on the first shear deformation theory (FSDT). The current analysis is performed based on the energy method. For the numerical investigation, Ritz method is applied, and for shape functions, Chebyshev polynomials are utilized. It is found that the number of layers is effective on the buckling load and natural frequency of laminates which made from non-uniform layers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1125-1133
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• 2001

Since the surface temperature of the evaporating tube in an ammonia unit cooled is lower than the dew point of atmosphere, the moisture in the atmosphere condenses and the frost grows on the tube. The frost of liquid film decreases the heat transfer rate. The reliable analysis of the heat transfer is required for the prediction of the optimal design of the ammonia unit cooler. For the specific commercial model, the performance was numerical1y estimated for the variation of operating condition and geometric configuration. It is found that there exists an optimum range for the parameters such as mass flow rate of air and refrigerant, humidity, refrigerant quality, fin pitch, the number of step, the number of rows and the pattern of refrigerant path.

• International Journal of CAD/CAM
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• v.2 no.1
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• pp.45-54
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• 2002

Given a set of three generator circles in a plane, we want to find a circumcircle of these generators. This problem is a part of well-known Apollonius' $10^{th}$ Problem and is frequently encountered in various geometric computations such as the Voronoi diagram for circles. It turns out that this seemingly trivial problem is not at all easy to solve in a general setting. In addition, there can be several degenerate configurations of the generators. For example, there may not exist any circumcircle, or there could be one or two circumcircle(s) depending on the generator configuration. Sometimes, a circumcircle itself may degenerate to a line. We show that the problem can be reduced to a point location problem among the regions bounded by two lines and two transformed circles via $M{\ddot{o}}bius$ transformations in a complex space. The presented algorithm is simple and the required computation is negligible. In addition, several degenerate cases are all incorporated into a unified framework.

• Journal of the Korean housing association
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• v.10 no.3
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• pp.103-117
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• 1999

Little research has been done regarding the explicit and objective analysis and explanation of the spatial logic of traditional Korean settlement patterns, in spite of many archeological and socio-historical studies. In this paper we present research into spatial mechanisms and their social meanings in three traditional villages in the southern province of Korea. Conventional space-syntax analysis of spatial configuration has been used to analysis and investigate the morphological forms and functions of the traditional villages. The research results show that the traditional Korean villages are spatially deeper and syntactically less connected than other comparable urban forms, such as old European cities. Configurational analysis of the three villages reveals that their spatial structures are configured to have their own spatial logic, not a geometric order but a spatial structure. What is however noteworthy is the way they embrace their own environmental context and factors and implement them into the process of urban growth or spatial construction.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2426-2428
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• 2003

본 논문은 IEEE 1394 통신을 기반으로 하는 센서보드를 개발하고 센서보드의 초음파 센서만을 이용하는 이동 로봇의 지도 생성 및 위치 추정을 위한 과정에서 효과적인 초음파 센서 구성과 그에 따른 주변 환경 인식 방법을 소개한다. 일반적으로 이동 로봇의 주행을 위해서 시각센서, 초음파 센서, 레이저 센서 등과 같은 많은 센서들을 사용한다. 시각 센서나 레이저 센서를 이용하면 정확한 정보를 얻을 수 있으나 가격이 비싸다는 단점이 있다. 초음파 센서는 저렴하고, 데이터 처리와 사용이 쉽지만 반사각 민감성 같은 초음파의 특성상 일반적으로 자애물의 판별 여무에만 사용되는 경우가 많다. 따라서 본 문에서는 다중 초음파 센서만을 이용한 로봇의 위치 인식 문제를 보완하여 주변 환경 인식 방법을 소개한다.

• Nuclear Engineering and Technology
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• v.36 no.2
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• pp.127-141
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• 2004

Various types of integrated steam generators, which integrate IHTS and a steam generator into a single unit of equipment for an LMR, were analyzed using an analytic solution with some simplification. The analysis showed that the undesirable reversed heat transfer, of which occurrence was previously observed only in an integrated single-region bundle type, can also occur in an integrated double-region bundle type. The mechanism of the reversed heat transfer occurrence in the double-region type is explained and it is shown the mechanism in the double-region type is completely different from that in the single-region type. Based on this finding, a method for preventing the aforementioned heat transfer is suggested. The performance of the four types of the integrated steam generators is assessed. For this assessment, a SG is actually designed for each type and the optimization in the geometric parameters and flow rate are optimized.

• Journal of Institute of Convergence Technology
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• v.7 no.2
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• pp.1-5
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• 2017

The rotating electrodynamic wheel over a conductive plate produces thrust force as well as normal force. Specially, separating the conductive plate and spacing apart each part, the lateral stability of the rotating wheel is guaranteed due to the restoring force into neutral position. In this paper, the force characteristics of the electrodynamic wheel rotating over the conductive plate is analyzed using the finite element tool. First, the dominant parameters are identified considering the geometric configuration and the operating condition. And the sensitivity for the parameter deviation is quantified for the high force density. The above topology can be applied as an actuating principle for inter-city train as well as contact-free transfer device.

• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.135-138
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• 1985

A new flexible $N_2O_2$-type tetradentate ligand, ethylene-diamine-N,N'-di-${\alpha}$-butyric acid (eddb), has been synthesized, and a series of cobalt (III) complexes of eddb, $[Co(edda)(L)]^{n+}$ (L = $Cl_2$, $(H_2O)_2$, $Cl\;H_2O$, and $Co^2_3$), have been prepared. Only s-cis isomers have been yielded during the preparation of complexes. Ring strain is cited as the primary cause for the preference for the s-cis geometric configuration.

• Structural Engineering and Mechanics
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• v.41 no.6
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• pp.775-789
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• 2012

This paper focuses on post-buckling analysis of functionally graded Timoshenko beam subjected to thermal loading by using the total Lagrangian Timoshenko beam element approximation. Material properties of the beam change in the thickness direction according to a power-law function. The beam is clamped at both ends. The considered highly non-linear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. As far as the authors know, there is no study on the post-buckling analysis of functionally graded Timoshenko beams under thermal loading considering full geometric non-linearity investigated by using finite element method. The convergence studies are made and the obtained results are compared with the published results. In the study, with the effects of material gradient property and thermal load, the relationships between deflections, end constraint forces, thermal buckling configuration and stress distributions through the thickness of the beams are illustrated in detail in post-buckling case.