• 한국정밀공학회지
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• 제14권12호
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• pp.143-152
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• 1997

The deflection of an end mill is very important in machining process and cutting simulation because it affects directly workpiece accuracy, cutting force, and chattering. In this study, the deflection of the end mill was studied both experimentally and by using finite element analysis. And the moment of inertia of cross sections of the helical end mill is calculated for the determination of the relation between geometry of radial cross section and rigidity of the tools. Using the Bernoulli-Euler beam theory and the concept of equivalent diameter, a deflection model is established, which includes most influences from tool geomety parameters. It was found that helix angle attenuates the rigidity of the end mill by the finite element analysis. As a result, the equivalent diameter is determined by tooth number, inscribed diameter ratio, cross sectional geometry and helix angle. Because the relation betweem equivalent diameter and each factor is nonlinear, neural network is used to decide the equivalent diameter. Input patterns and desired outputs for the neural network are obtained by FEM analysis in several case of end milling operations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.896-902
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• 2005

An orthopedic surgeon normally gets the operational parameters of total knee arthroplasty from medical images(CT, MRI). Anatomical axis, mechanical axis, the width and height of femur, or tibia are the most important parameters related with accomplishment of TKA. This paper presents a methodology of simulation that virtually operates TKA according to 2D medical images. Using this simulator, some important parameters for operation can be achieved before hand. The simulator provides the 3D computational model of a knee joint and then derives the proper size of implant corresponding to the joint. The whole process of TKA can be simulated such as clipping a knee joint, assembling the joint and its implants, visualizing all the operation steps, deriving some crucial parameters such as anatomical axis and cutting thickness, and predicting the result of TKA. Some examples are given and discussed to validate the methodology.

• 한국정밀공학회지
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• 제32권5호
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• pp.405-413
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• 2015

This paper presents the motion accuracy simulation considering loads such as workpiece weight, cutting force, cogging force of a linear motor, and force caused by misalignment and runout error of a ballscrew in linear motion units. The transfer function method is basically utilized to estimate 5-DOF motion errors, together with the equilibrium equations of force and moment on the table. The transfer function method is modified in order to consider clearance changed according to the loads in the double sided hydrostatic/aerostatic bearings. Then, the analytic model for predicting the 5-DOF motion errors is proposed with the modified transfer function method. Motion errors were simulated under different loading conditions in the linear motion units using hydrostatic, aerostatic, and linear motion bearings, respectively. And the proposed analytic model was verified by comparing the estimated and measured motion errors.

• Journal of the Korean Wood Science and Technology
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• 제24권2호
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• pp.71-80
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• 1996

Handling the manufacured goods is the most cost-consuming task in material handling system in wooden furniture industries. Fully automated warehouse for cartoned goods of a furniture manufacturing company was analized to provide plant engineers and managers with some important informations on the utility and profitability of the automated storage and retrieval system(AS/RS). Process-oriented simulation modeling tech-niques were used to describe the system and to propose some alternatives to promote the efficiency of AS/RS. Simulation report could be inter-preted as follows: 1. Warehouse for the furniture goods must be designed in accordance with reliable material handling program and constructed with suitable equipments depending on the specification of packed products. 2. An excess of palletized products induced the indigestion and the inefficiency of AS/RS of the furniture industry and put this high-costly system into the shade. 3. Overcrowded AS/RS of the furniture factories could regain its material handling function by cutting down the deposit of products into the automated warehouse. For this purpose, reducing the regular output and direct delivering the outside products to the destination should be considered as the definite counterplan. And additional operation of conventional handy warehouse was also expected to improve the efficiency of main AS/RS.

• 한국멀티미디어학회논문지
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• 제22권7호
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• pp.790-803
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• 2019

The effects of different heat treatments on the sensory characteristics of abalones are studied in this study. In this paper, the sensory evaluation of abalone samples under different heat treatment conditions is carried out, and the evaluation results are analyzed. The three-dimensional (3D) scanning and reverse engineering are used in tooth modeling of the sensory evaluation of abalone samples under different heat treatment conditions. Besides, the chewing movement models are simplified into three modes, including the cutting mode, compressing mode and grinding mode, which are simulated using finite element simulation. The elastic modulus of the abalone samples is obtained through the compression testing using a texture analyzer to distinguish their material properties under different heat treatments and to obtain simulated mechanical parameters. Finally, taking the mechanical parameters of the finite element simulation of abalone chewing as input and sensory evaluation parameters as the output, BP neural network is established in which the sensory texture evaluation model of abalone samples is obtained. Through verification, the neural network prediction model can meet the requirements of food texture evaluation, with an average error of 9.12%.

• Earthquakes and Structures
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• 제25권2호
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• pp.113-123
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• 2023

A novel type of buckling restrained brace with built-up angle steel was developed. The core segment was formed by welding angle steel, and the middle section was reduced by cutting technology to solve the problem that the end of BRB was easy to buckle. The experimental program has been undertaken to study the performance of BRBs with different unbonded materials (silica gel, kraft paper) and different filler materials (ordinary concrete, full light-weight concrete). Four specimens were designed and fabricated for low cycle reciprocating load tests to simulate horizontal seismic action. The failure mode, hysteretic curves, tension-compression unbalance coefficient and other mechanical parameters were compared and analyzed. The finite element software ABAQUS was used to conduct numerical simulation, and the simulation results were compared with the experimental phenomena. The test results indicated that the hysteretic curve of each specimen was plump. Sustaining cumulative strains of each specimen was greater than the minimum value of 200 required by the code, which indicated the ductility of BRB was relatively good. The energy dissipation coefficient of the specimen with silica gel as unbonded material was about 13% higher than that with kraft paper. The experimental results were in good agreement with the simulation results.

• 한국시뮬레이션학회논문지
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• 제22권1호
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• pp.31-40
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• 2013

과학기술의 발전으로 대한민국 해군의 함정 등의 무기체계는 첨단화, 과학화 되면서, 무기체계를 도입 및 운영, 유지하는 비용도 크게 증가한 반면, 이를 위한 국방비는 한정되어 있다. 따라서, 최적화된 예산을 사용하면서 적절한 가용도를 유지하기 위해 함정 가동에 영향을 주는 수리부속에 대한 효율적이고 과학적인 관리가 필요하다. 이를 위해 본 연구에서는 복구성 수리부속의 재고수준에 따른 가용도를 산출하는 시물레이션 재고관리 모형을 제시하였다. 제시된 모델은 기존의 복구성 수리부속의 다단계 재고관리모형인 METRIC 모형을 바탕으로 계획정비, 재생율, 전환보급, 동류전용 등의 현실적인 개념을 순차적으로 반영한 5개의 모델로 구성되어 있다. 실험은 각 모델에 같은 재고수준량을 입력하여 가용도의 결과값을 산출하도록 진행하였으며, 추가적인 민감도 분석을 실시하였다. 실험결과 각 모델별 가용도의 차이가 있었으며, 따라서, 해군의 운영특성을 반영한 재고관리 모델의 개발이 필요함을 확인하였다.

• 한국터널지하공간학회 논문집
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• 제23권1호
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• pp.1-12
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• 2021

Tunnel boring machine (TBM)의 설계에 있어서 지반과 직접적으로 맞닿아 절삭을 담당하는 커터헤드의 설계에 따라서 장비의 굴진효율이 달라지게 된다. 디스크커터는 배치되는 위치에 따라 센터 커터 존, 이너 커터 존, 트렌지션 커터 존으로 구분된다. 기존에도 페이스커터의 최적 절삭조건을 규명하기 위한 연구는 많이 진행되어 왔으나, 트렌지션 커터의 최적 절삭조건을 규명하기 위한 연구는 상대적으로 미진하였다. 본 연구에서는 트렌지션 커터의 최적의 절삭조건을 규명하기 위해 개별요소법 수치해석을 수행하고 트렌지션 커터 사이의 각도에 따른 비에너지 곡선을 작도하여 최적 절삭조건을 알아보고자 하였다. 수치해석 결과 전이영역에서 최소 비에너지를 보이는 트렌지션 커터 사이의 각도 9°인 것으로 확인되었다. 이를 트렌지션 커터의 경사각에 따라 3가지 영역으로 구분하고 영역별 디스크커터 사이의 각도와 비에너지를 정리한 결과 트렌지션 커터의 경사각이 커질수록 최적 비에너지를 보이는 트렌지션 커터 사이의 각도는 10°에서 8°까지 점차 감소하는 경향을 보였다. 이러한 결과는 기존에 사용되고 있는 트렌지션 커터의 설계 결과와 유사한 경향으로써, 본 연구의 결과를 밑받침한다.

• 대한구순구개열학회지
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• 제6권2호
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• pp.91-105
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• 2003

There are significant limitations in the precision of mandibular distraction in setting a desired occlusal and facial esthetic outcome. The purpose of this study is to present the simulation method for the distraction osteogenesis treatment planning. 3-D surgery simulation software programs V-works and V-Surgery(Cybermed, Seoul, Korea) were used from the 3D CT data in addition to the conventional data facial photography, panorama and cephalogram, dental cast model. We have utilized already for the various surgical procedures to get information preoperatively for the maxillofacial surgery like cancer localization and reconstructive surgery, orthognathic surgery and implant surgery in the department of Oral and Maxillofacial surgery, Seoul National University Hospital. On the software, bone cutting can be done at any place and any direction. Separated bone segment can be mobilized in all 3 dimensional direction. After the 3D simulation on the software program, mock surgery on the RP model can be performed. This planning method was applied to two hemifacial microsomia patients. With this protocol, we could simulate the movement of bony segment after maxillofacial distraction osteogenesis

• 산업경영시스템학회지
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• 제42권1호
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• pp.64-73
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• 2019

The manufacturing companies under Make-To-Order (MTO) production environment face highly variable requirements of the customers. It makes them difficult to establish preemptive production strategy through inventory management and demand forecasting. Therefore, the ability to establish an optimal production schedule that incorporates the various requirements of the customers is emphasized as the key success factor. In this study, we suggest a process of designing the simulation model for establishing production schedule and apply this model to the case of a flat glass processing company. The flat glass manufacturing industry is under MTO production environment. Academic research of flat glass industry is focused on minimizing the waste in the cutting process. In addition, in the practical view, the flat glass manufacturing companies tend to establish the production schedule based on the intuition of production manager and it results in failure of meeting the due date. Based on these findings, the case study aims to present the process of drawing up a production schedule through simulation modeling. The actual data of Korean flat glass processing company were used to make a monthly production schedule. To do this, five scenarios based on dispatching rules are considered and each scenario is evaluated by three key performance indicators for delivery compliance. We used B2MML (Business To Manufacturing Markup Language) schema for integrating manufacturing systems and simulations are carried out by using SIMIO simulation software. The results provide the basis for determining a suitable production schedule from the production manager's perspective.