• 한국CDE학회논문집
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• 제6권4호
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• pp.236-243
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• 2001

A key factor far realizing the internet-based virtual manufacturing system(VMS) and virtual enter-prise(VE) is how to precisely and effectively represent the machine elements and mechanics. In this paper, we present methods to represent the numerically controlled machine tools in the internet environment. The method is composed of: 1) geometrical modeling of the machine tools, 2) kinematic modeling for the movements of the machine tools, and 3) representing the developed model in the internet infrastructure. Based on the models. a web-based virtual machine tools (WVMT) is developed, and it can be accessed at hrrp://wvmt.postech.ac.kr. The WVMT can be used for various purposes: 1) web-based virtual manufacturing system, 2) web-based CAM system, and 3) CNC educational tools for the vocational school through internet.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.125-126
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.455-456
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• 2008

• 한국기계가공학회지
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• 제4권2호
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• pp.16-23
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• 2005

This study is intended to find out the reason of interference phenomenon of a machine tool when it operates for 5-axises working. The researcher made a Virtual Machine which has same figures of the 5 axises machine tool and Virtual Manufacturing System which has both Software factors - controller and NC code data to manipulate the movement characteristics of the machine - and Hardware factors - fixtures, workpiece, tools, holders and so on. With these virtual tools, this study is designed to find out the relation between the movement and the interference or collision, and also intended to verify the simulation and work-processing. In this study, the researcher found out, in case of the vertical 5 axises type, that it has more chances to have interference between the fixture, the workpiece and the main spindle including the tool holder due to the tilting kinetics of the main spindle. In case of the horizontal 5 axises type, on the other hand, the researcher found out that it has more possibility to have the interference between the main spindle and the rotary shaft.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.785-791
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• 2005

Reconfigurability of machine tools is one of the critical factors to realize the responsive manufacturing systems to satisfy the mass-customization production. This paper presents the methods to model and simulate the machine tools on Internet in response to change in the machining requirements. Specifically, a set of module combination rules and a modeling method of the structure of machine tools using connectivity graph are developed. In response to the user requirements, kinematic relations and structures of machine tools can be derived using the module combination rules and connectivity graph relationships. Internet-based simulator of machine tools is implemented and presented. The developed machine tool simulator can be used to verify the structure of machine tools derived from the user requirements.

• 한국정밀공학회지
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• 제29권10호
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• pp.1070-1077
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• 2012

Virtual machine tools have been magnified recently as manufacturers could estimate performances of machine tools before design and manufacturing of them. However, it requires much time and efforts to make FEM models and predict precision of machine tools well because machine tools are composed of many joints such as bolt joints, LM joints, rotational bearing joints and mounts. Especially, we have studied computational modeling methods of bolt joints to predict precision of machine tools well in this paper. Stiffness and damping coefficients of bolt joints are investigated and generalized with respect to fasten forces through experiments and FEM analysis. Matrix 27 element of ANSYS is used and bolt joints are simplified as square areas with 8 nodes to apply stiffness and damping simultaneously. Additionally, coordinate transformation of matrix 27 for bolt joints is induced to apply to skewed bolt joints of machine tools and evaluate it using FEM analysis.

• 한국정밀공학회지
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• 제26권4호
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• pp.39-46
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• 2009

• 한국정밀공학회지
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• 제29권10호
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• pp.1043-1049
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• 2012

The FEM analysis of machine tools is the general analysis process to evaluate machine performance in the industry for a long time. Despite advances in FEM software, because of difficult simplicity of CAD drawing, little experience of joints stiffness modeling and troublesome manual contact area divide for bindings, the industry designers think the FEM analysis is still an area of FEM analysis expert. In this paper, the automation of modeling process with simplicity of drawing, modeling of joints and contact area divide is aimed at easy FEM analysis to enlarge utilization of a virtual machine tools. In order to verify the effects of modeling automation, a slant bed type model with tilting table is analyzed. The results show FEM modeling automation method only needed 45 minutes to complete the whole modeling process, while manual modeling method requires almost one month with 8200 calculations for coordinate transformations and stiffness data input.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.854-861
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• 2005

The functional behavior of a portable consumer electronic (PCE) product is nearly all expressed with human-machine interaction (HMI) tasks. Although physical prototyping and computer aided design (CAD) software can show the appearance of the product, they cannot properly reflect its functional behavior. In this paper, we propose a virtual prototyping (VP) system that incorporates virtual reality and HMI functional simulation in order to enables users to capture not only the realistic look of a PCE product but also its functional behavior. We obtain geometric part models of the product and their assembly and kinematics information with the help of CAD and reverse engineering tools, and visualize them with various display tools. We adopt state transition methodology to capture the HMI functional behavior of the product into a state transition chart, which is later used to construct a finite state machine (FSM) for the functional simulation of the product. The FSM plays an important role to control the transition between states of the product. The proposed VP system receives input events such as mouse clicks on buttons and switches of the virtual prototype model, and it reacts to the events based on the FSM by activating associated activities. The VP system provides the realistic visualization of the product and the vivid simulation of its functional behavior. It can easily allow users to perform functional evaluation and usability testing. Moreover, it can greatly reduce communication errors occurring in a typical product development process. A case study about VP of an MP3 player is given to show the usefulness of the proposed VP system.

• 정보보호학회논문지
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• 제18권6A호
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• pp.163-177
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• 2008

오늘날 많은 기업들이 비용절감을 위해 서버 가상화 기술의 이용 및 보급을 확대함에 따라 가상화 서버에서의 사이버범 죄도 크게 증가할 것으로 예상된다. 서버 가상화 솔루션은 각 가상화 서버에 대한 가상머신 이미지를 생성하는 기능을 기본적으로 제공하기 때문에 서버 가상화 환경에서는 기존의 디지털 포렌식 수사과정의 디스크 이미지 수집과정을 생략하고 가상머신 이미지를 법적증거로 직접 활용함으로써 보다 신속하고 효율적인 수사가 가능하다. 하지만 가상화 서버의 구조적 특징으로 인해 나타날 수 있는 보안 취약성, 그리고 서버 가상화 솔루션의 신뢰성과 증거수집 절차상의 문제들로 인해 가상머신 이미지 자체만으로는 법적증거로서의 허용성을 인정받지 못한다. 본 논문에서는 가상머신 이미지가 법적증거로서 허용성을 인정받기 위해 서버 가상화 솔루션이 갖추어야 할 보안 요구사항, 디지털 포렌식 도구로서의 신뢰성 조건들을 도출하였으며, 가상머신 이미지가 증거로서의 연계보관성을 만족시키기 위해 갖추어야할 부가요소들을 제안한다. 또한 이러한 조건들을 통해 가상머신 이미지 증거가 미국 연방증거법의 법적 허용성 기준들을 만족시키는지 살펴보고, 이를 위한 관련 기관들의 구체적인 역할 및 세부 추진계획들을 제안한다.