• 한국멀티미디어학회논문지
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• 제19권11호
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• pp.1900-1908
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• 2016

Recent times have seen the introduction of modeling technologies using implicit surface and marching cubes algorithm in the field of computer graphics. Implicit surface modeling is used to express characters or fluid. This study presents a calculation method for the density of curve skeletal primitives using parametric curve and implements an implicit surface modeling tool by utilizing Maya API. Skeletal primitives can be assembled and utilized in character modeling using the implemented modeling tool. Results could be obtained more effectively compared to existing particle-based methods.

• 한국CDE학회논문집
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• 제3권3호
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• pp.168-176
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• 1998

This paper deals with an application on the mould machining of air intake hose product by using 3-dimensional parametric modeling techniques. The detailed domain is the 3-dimensional product with similar shapes and different sizes which needs too much working time for preparation of modeling or machining due to making a trial and errors repeatedly. Decision making rules for selection of modeling order and technique, and for calculation of cutting conditions, and for determination of sequence and method concerning machining operations are required by interview of expert engineers in the field. The developed expert system of modeling and machining is programmed by using a user programming language under the CAD/CAM software of the Personal Designer. The developed system that aids a mould engineer who is working in the modeling and machining section which deal with air intake hose product provides strong and useful capabilities.

• 한국항공우주학회지
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• 제47권8호
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• pp.566-573
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• 2019

항공 SAR에서 고품질의 영상을 얻기 위해서는 영상 획득 구간에서 항공기의 요동을 정확히 측정하여야 한다. 특히 요동측정을 할 때 상대적 위치오차 및 불연속성 오차를 줄여야 한다. 이를 해결하기 위해 본 논문에서는 합성 개구 레이더(SAR)에서 실시간으로 요동측정을 하는 매개변수 사전 오차 모델링 방법(P-PEM, Pre-Parametric Error Modeling)을 제안한다. P-PEM은 기존에 본 연구진에서 제안한 항법오차를 다항식으로 모델링하여 추정하는 매개변수 오차 모델링 기법(PEM, Parametric Error Modeling)에서 확장된 기법이다. PEM은 IMU에 의한 INS 오차를 짧은 시간 동안 다항식이라 가정하여 모델링하는 요동측정기법이다. 반면, P-PEM은 다항식 오차 모델의 계수를 미리 추정하고 영상촬영단계에서 사용한다. 시뮬레이션 결과, P-PEM을 적용하면 실시간으로 불연속성 오차를 제거한 요동측정이 가능함을 확인하였다.

• 한국실내디자인학회논문집
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• 제25권6호
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• pp.70-78
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• 2016

This paper aims to describe a case study of parametric interior design based on BIM (Building Information Modeling). As the practical use of BIM-based design grows, its influence expands into the field of interior architecture design. BIM makes possible to check various design plan, reach decision making in an effective way, and change design plan in an efficient method. Therefore, BIM is also promising field in interior architecture design. However, compared to other fields in architecture, engineering, and construction (AEC) industry, there have been less research and projects on BIM in the field of interior architecture. For increasing the feasibility of adapting BIM in interior architecture design, this paper describes a case study-projecting images for designing interior panels using parametric modeling. This process needs elaborate, delicate, and precise steps for harmonious output. For continuous use of building, users look forward to the design which variable and changeable according to user's preference and environment. Therefore, demand for parametric design in the interior design part such as panel pattern design for various decoration is growing. Treated process in this paper deals with an advanced phase which much effective in decreasing time consumption and useless part of process. Finally, this paper suggests the possibility of using BIM in the interior design process and field where BIM can be applied.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6751-6755
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• 2013

Background: Research on cancers with a high rate of mortality such as those occurring in the stomach requires using models which can provide a closer examination of disease processes and provide researchers with more accurate data. Various models have been designed based on this issue and the present study aimed at evaluating such models. Materials and Methods: Data from 330 patients with gastric cancer undergoing surgery at Iran Cancer Institute from 1995 to 1999 were analyzed. Cox-Snell Residuals and Akaike Information Criterion were used to compare parametric and semi-parametric Cox models in modeling transition rates among different states of a multi-state model. R 2.15.1 software was used for all data analyses. Results: Analysis of Cox-Snell Residuals and Akaike Information Criterion for all probable transitions among different states revealed that parametric models represented a better fitness. Log-logistic, Gompertz and Log-normal models were good choices for modeling transition rate for relapse hazard (state $1{\rightarrow}state$ 2), death hazard without a relapse (state $1{\rightarrow}state$ 3) and death hazard with a relapse (state $2{\rightarrow}state$ 3), respectively. Conclusions: Although the semi-parametric Cox model is often used by most cancer researchers in modeling transition rates of multistate models, parametric models in similar situations- as they do not need proportional hazards assumption and consider a specific statistical distribution for time to occurrence of next state in case this assumption is not made - are more credible alternatives.

• 한국BIM학회 논문집
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• 제2권2호
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• pp.37-45
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• 2012

부재를 표준화하여 설계 및 제작 생산성을 높이고 기계화 시공을 가능하게 하는 모듈러 교량이 건설 산업에서 중요하게 대두되고 있다. 반복성이 높고 설계, 제작 시공 과정에서의 정보의 원활한 전달이 필요하기 때문에 BIM(Building Information Modeling) 기술에 기반한 변수 모델링 정의를 제시하였다. 모듈러 교량이 갖는 변수 범위를 고려하여 고정변수, 변동변수, 연관변수로 구분하여 정의하고 이를 설계, 해석, 제작에 활용할 수 있도록 하였다. 구조시스템 개발과정의 지식을 정보화하여 3차원 모델의 정확성과 활용성을 높였다.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.370-379
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• 2015

Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.727-731
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• 2000

This paper presents a new practical autopilot design approach to acceleration control for tail-controlled STT(Skid-to-Turn) missiles. The approach is novel in that the proposed parametric affine missile model adopts acceleration as th controlled output and considers the couplings between the forces as well as the moments and control fin deflections. The aerodynamic coefficients in the proposed model are expressed in a closed form with fittable parameters over the whole operating range. The parameters are fitted from aerodynamic coefficient look-up tables by the function approximation technique which is based on the combination of local parametric models through curve fitting using the corresponding influence functions. In this paper in order to employ the results of parametric affine modeling in the autopilot controller design we derived a parametric affine missile model and designed a feedback linearizing controller for the obtained model. Stability analysis for the overall closed loop sys-tem is provided considering the uncertainties arising from approximation errors. the validity of the proposed modeling and control approach is demonstrated through simulations for an STT missile.

• 한국전산구조공학회논문집
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• 제23권4호
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• pp.417-424
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• 2010

변단면을 갖는 FCM(Free Cantilever Method) 교량의 초기 설계단계에서 설계변경에 따른 반복적 작업에 대한 효율성 향상을 위하여 박스거더의 종방향 형상을 자동조정할 수 있도록 하는 파라메트릭 모델링 방법을 연구하였다. FCM 교량의 종방향 형상을 표현하기 위한 매개변수를 정의하였으며, 기존 FCM 교량의 설계 시 적용된 매개변수의 통계치 적용을 통해 매개변수들 간의 내재적, 외재적 구속조건 및 함수관계를 정의하였다. 정의한 구속조건 및 관계를 적용한 파라메트릭 모델링 구현을 통해 그 적용 가능성을 검증하였으며, 기존 설계된 교량을 대상으로 파라메트릭 모델링을 수행한 결과로 생성된 3차원 교량 모델의 콘크리트 물량과 대상교량의 설계문서 상의 물량 비교를 통해 모델의 정확성을 확인하였다.

• 산업경영시스템학회지
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• 제23권57호
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• pp.87-92
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• 2000

This paper describes a three dimensional parametric modeling system for transmission gears of tractor. In conventional design and manufacturing, information about three dimensional shapes has been described in engineering drawings. However drawing based design presents several problems; 1) communication errors between the designer and the modeller or manufacturer. 2) time taken and costs incurred in the design process. To solve these problems the system of parametric design based modeling has been proposed. Developed system in this paper consists of four steps; 1) parametric design of transmission gears with a solid modeler. 2) evaluation of gear geometry and strength. 3) dynamic simulation for gear interference check. 4) gear stress analysis with a CAE software. The proposed system has been tested in the fields and found to be a useful system.