• 대한기계학회논문집A
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• 제29권3호
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• pp.395-402
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• 2005

Recently Multidisciplinary Design Optimization Based on Independent Subspaces (MDOIS), an MDO (multidisciplinary design optimization) algorithm, has been proposed. In this research, an MDO problem is defined for design of a belt integrated seat considering crashworthiness, and MDOIS is applied to solve the problem. The crash model consists of an airbag, a belt integrated seat (BIS), an energy absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural nonlin- ear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified and is addressed in the system analysis step in MDOIS. Interdisciplinary variables are belt load and stiffness of the seat, which are determined in system analysis step. The belt load is passed to the structural analysis subspace and stiffness of the seat back frame to the occupant analysis subspace. Determined design vari- ables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and Head Injury Crite- rion (HIC) of an occupant are reduced with specified constraints satisfied at the same time. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formu - lated to solve the system analysis. The results from MDOIS are discussed.

• Advances in Computational Design
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• 제3권1호
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• pp.49-69
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• 2018

This paper shows an optimal design for reinforced concrete rectangular combined footings based on a criterion of minimum cost. The classical design method for reinforced concrete rectangular combined footings is: First, a dimension is proposed that should comply with the allowable stresses (Minimum stress should be equal or greater than zero, and maximum stress must be equal or less than the allowable capacity withstand by the soil); subsequently, the effective depth is obtained due to the maximum moment and this effective depth is checked against the bending shear and the punching shear until, it complies with these conditions, and then the steel reinforcement is obtained, but this is not guaranteed that obtained cost is a minimum cost. A numerical experimentation shows the model capability to estimate the minimum cost design of the materials used for a rectangular combined footing that supports two columns under an axial load and moments in two directions at each column in accordance to the building code requirements for structural concrete and commentary (ACI 318S-14). Numerical experimentation is developed by modifying the values of the rectangular combined footing to from "d" (Effective depth), "b" (Short dimension), "a" (Greater dimension), "${\rho}_{P1}$" (Ratio of reinforcement steel under column 1), "${\rho}_{P2}$" (Ratio of reinforcement steel under column 2), "${\rho}_{yLB}$" (Ratio of longitudinal reinforcement steel in the bottom), "${\rho}_{yLT}$" (Ratio of longitudinal reinforcement steel at the top). Results show that the optimal design is more economical and more precise with respect to the classical design. Therefore, the optimal design presented in this paper should be used to obtain the minimum cost design for reinforced concrete rectangular combined footings.

• 대한족부족관절학회지
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• 제17권1호
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• pp.52-59
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• 2013

Purpose: The purpose of this study is to evaluate treatment results of multidisciplinary approach of critical ischemic limb with diabetic foot. Materials and Methods: From March 2005 to March 2012, 674 diabetic foot patients were analyzed. Among them, 85 patients were neuroarthropathic type, 383 patients were infectious type, and 206 patients were ischemic type. The subjects were 206 patients who had critical ischemic limbs and major or minor amputations were done. Various single or combined treatment method before amputation was performed. We investigated their ABI, HbA1c, main occlusion lesion, limb salvage and hospitalization period by various treatment method. Results: Major amputation was 27 cases, minor amputation was 179 cases. Mean HbA1c was 8.2%, and mean ABI was 0.66. Main occlusion lesion was 6 cases at common iliac artery, 13 cases at external iliac artery, 9 cases at internal iliac artery, 11 cases at common femoral artery, 23 cases at deep femoral artery, 52 cases at superficial femoral artery, 35 cases at popliteal artery, 40 cases at posterior tibia artery, 35 cases at anterior tibial artery, 28 cases at peroneal artery, and 13 cases at dorsalis pedis artery. Major amputations were decreased, minor amputations were increased, and hospitalization period was reduced by treatment of multidisciplinary approach. Conclusion: Treatment of multidisciplinary approach, which include preoperation percutaneus transluminal angioplasty, vascular surgery, and amputation, of critical ischemic limb with diabetic foot had advantages of limb salvage and hospitalization period reduction.

• 한국결정성장학회지
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• 제14권6호
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• pp.233-235
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• 2004

Shaped single crystals of Bi : $Y_3Ga_5O_{12}$(Bi = 0.041, 0.047 and 0.061 mol%) were grown by the micro-pulling-down method. Optical absorption spectra show an absorption band at 288 nm ascribed to the lowest energy $6s^2$ \longrightarrow 6s6p transition of $Bi^{3+}$ , while luminescence spectra demonstrate the band at 314 nm ascribed to the reverse radiative transition of the excited $Bi^{3+}$ centres. At room temperature, dominant decay time component was found to be about 440 ns with a minor slower component 580 ns.

• 대한치과교정학회지
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• 제47권6호
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• pp.384-393
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• 2017

Fusion of teeth is a developmental anomaly. It occurs at the stage of tooth formation, which determines the shape and size of the tooth crown, when one or more teeth fuse at the dentin level during the morphodifferentiation of the dental germs. Such teeth show macrodontia and may cause crowding, as well as esthetic and endodontic problems. In this article, we report a rare case of a maxillary central incisor fused to a supernumerary tooth showing labial and palatal talon cusps, which was orthodontically moved across the midpalatal suture. A 13-year-old Caucasian boy sought treatment for the unesthetic appearance of his maxillary central incisor and anterior crowding. He was rehabilitated successfully via a multidisciplinary approach involving orthodontic, nonsurgical endodontic, periodontal, and prosthodontic treatments. After a 26-month treatment period, the patient's macroesthetics and microesthetics were improved. The overall improvement of this macrodontic tooth and its surrounding tissues through multidisciplinary treatment was documented using cone-beam computed tomography.

• 대한기계학회논문집A
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• 제31권12호
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• pp.1150-1156
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• 2007

Multidisciplinary design optimization methodologies play an essential role in modern engineering design which involves many inter-related disciplines. These methodologies usually require very long computing time and design tasks are hard to finish within a specified design cycle time. Parallel processing can be effectively utilized to reduce the computing time. The research on the parallel computing performance of MDO methodologies has been just begun and developing. This study investigates performances of MDF, IDF, SAND and CO among MDO methodologies in view of parallel computing. Finally, the best out of four methodologies is suggested for parallel processing purpose.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.380-385
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• 2001

The paper presents a new multidisciplinary design optimization architecture using optimal sensitivity and coordination of interdisciplinary design variables. Original design problem is decomposed into a number of sub-problems that represent individual engineering analysis. The coupled effects between sub-problems are computed by interdisciplinary design variables. System level coordination is determined by optimal parameter sensitivity calculated by finite difference method. The proposed. MDO strategy is applied to a simplified model of rotorcraft blade design associated with structures and aerodynamic disciplines.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.209-217
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• 2002

This gaper discusses a multidisciplinary design optimization of the engine mounting system to improve the ride quality of a vehicle and to remove the possibility of the resonance between the powertrain system and vehicle systems. The driveline model attempts to support engine mount development by providing sufficient detail for design modification assessment in a modeling environment. Design variables used in this study are the locations, the angles and the stiffness of an engine mount system. The goal of the optimization is both decoupling the roll mode ova powertrain and minimizing the vibration transmitted to the vehicle including the powertrain, simultaneously. By applying forced vibration analysis for vehicle systems and mode decouple analysis for the engine mount system, it is shown that improved optimization result is obtained.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.85-86
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• 2011

In this paper, the virtual power grid of Jeju in 2020 is modelled including not only VSC HVDC(Voltage Source Current-High Voltage Direct Current) but also wind power generators as 200MW for onshore and 500MW for offshore by PSCAD/EMTDC. Each active power and reactive power are able to controlled by the VSC HVDC. In addition, to verify the characteristic of the modeling VSC HVDC, those wind power generators are cut off from the grid. The result show that the modeling power grid of Jeju become stabilized after 0.1second from failure.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.1-10
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• 2005

A new approach, Multi-Objective Design Exploration (MODE), is presented to address Multidisciplinary Design Optimization (MDO) problems by CFD-CSD coupling. MODE reveals the structure of the design space from the trade-off information and visualizes it as a panorama for Decision Maker. The present form of MODE consists of Kriging Model, Adaptive Range Multi Objective Genetic Algorithms, Analysis of Variance and Self-Organizing Map. The main emphasis of this approach is visual data mining. An MDO system using high fidelity simulation codes, Navier-Stokes solver and NASTRAN, has been developed and applied to a regional-jet wing design. Because the optimization system becomes very computationally expensive, only brief exploration of the design space has been performed. However, data mining result demonstrates that design knowledge can produce a good design even from the brief design exploration.