• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.2
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• pp.17-22
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• 2003

Electropolishing is the electrolytic removal of metal in a highly ionic solution by means of an electrical potential and current. It is normally used to remove a very thin layer of material on the surface of a metal part or component. Electropolishing is able to enhance the material properties of a workpiece and to change its physical dimensions. Also, It is suitable for the polishing of both complex shapes and hardened materials, which are difficult to machine mechanically. therefore, the aim of the present study is to investigate the characteristic of Electropolishing A12024 in terms of current density, polishing time and electrode gap, etc.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.3
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• pp.45-51
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• 2003

Milling process has beer used in aircraft, auto-component and mold industries widely. They need more accurate and precise parts to improve the performance and quality of their products. So, the geometrical form accuracy of the workpiece surface generated by this process is getting more and more important. Generally, the form accuracy is affected by machine conditions, cutting conditions, tool geometry, tool deflection by cutting force and tool path md so on. Even though they are controlled as perfect conditions, it is easily found that there is a line along the axis of a cylindrically milled part. It is presumed that the tool approaching causes this error on milled surface. Thus, the study for investigating the effect of the tool approaching path on the cylindrical surface geometry of the end-milled part is carried out.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.947-950
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• 2007

In this study, vibration analysis of a refrigerator was carried out to reduce vibration by considering grommet. When the refrigerator machine room is modeled by finite element method, spring elements are added to constructions of the FEmodel for each component and update. To design the grommet of refrigerator, FEmodel must have vibration characteristics of each components such as baseplate, pipe and compressor it self. The modal analyses are conducted to validate suggested approach when the components of machine room are assembled together. And, in this study, optimal design of grommet is conducted to avoid the resonance at the operating frequency of refrigerator. The experimental and FEM result of suggested design showed good agreement and are presented here.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.126-132
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• 1991

Various diagnostic techniques have been proposed according to the development of the engineering. and the machine elements. Specially. since the bearing is an essential component in rotating Machine. Many researchers have been done an earler detection and a exact diagnosis of defects on bearing. In this study, the technique which differ from past diagnosises techniques in frequency domain such as Spectral analysis is proposed. Parametric ARMA model was utilized to define the system using tire series directly. Based on the resulted ARMA parameters, more precies and faster diagnosis system through Neural network was presented.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.589-592
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• 2000

자동차 man-machine system의 interface를 이루는 Display panel, Center fascia, Steering wheel, Rear view, Gear, Power window switch, Seat 등과 이들의 Layout은 운전자의 안전뿐만 아니라, 안락감과 밀접한 부분으로 알려져 있다. 따라서 이러한 설계요소들의 Man-machine interface의 최적화를 위한 인간공학적 접근이 필요하다. 운전자의 안락감은 Seat, Pedal, Steering wheel 등 뿐만 아니라 각종 조작장치(Audio, Switch, Gear,…)도 함께 연구되어야 하다. 따라서, 본 연구에서는 실험용 Seating buck을 제작하여 실내 조작장치 중 오디오를 대상으로 터치스크린과 Rapid Prototype을 이용해 사용성 평가에 대한 적합성을 검증하고자 하였다. Rapid Prototyping 기법은 디자인단계에서 제품 사용상의 문제점을 발견 개선할 수 있다는 장점이 있다. 그러나, 본 연구 결과에서 3가지 항목 중 1가지만이 실제 Audio와 Prototype에서 차이가 없었다. 따라서, Prototype의 접촉감과 입체감의 개선, 실사용과 동일한 환경의 제시, 소리와 같은 정확한 반응의 제시, Glare의 제거, 사용자 분석에 따른 실험 데이터의 축적 등을 고려하여 Rapid Prototyping을 구현하여야 할 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2075-2078
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• 2002

최근 이동내장형 시스템 기술이 차세대 정보통신 산업의 주력으로 급부상함에 따라 다양한 이기종 제품간의 호환성과 이식성 제공의 핵심 역할을 수행하는 자바가상머신(Java Virtual Machine)이 주목받고 있다. 가상머신을 컴포넌트 기반 소프트웨어 기술을 사용하여 구축한다면, 재사용과 재구성이 용이해 저렴하고 신뢰성 있는 가상머신 개발이 가능해진다. 이러한 이유로 인하여, 컴포넌트기반 내장형 실시간 시스템을 효과적이고 체계적으로 개발하고 검증하기 위한 개발 툴셋의 중요성도 동시에 증대되고 있다. 따라서 본 논문에서는 PBO(Port-Based Object) 모델을 확장하여 자바가상머신 컴포넌트들을 툴셋에서 제공하는 구성 툴에 의해 조립과 검사를 수행하며, 빠르게 재사용성과 신뢰성을 지원하는 자바가상머신을 개발할 수 있는 환경를 제안한다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.192-197
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• 1998

Abrasive flow machining is useful to abrasive polish a internal or external surface of the free shape dimensional parts, which are used in many fields such as machine tool parts, semi-conductor, and medical component industries. The machining process is that two hydraulic cylinders, which are located surface to surface, are enforce media to the passage between workpiece and tooling part alternately, and then the abrasives included in the media pass the passage and polish the surface of workpiece. The media which is made of polymer and abrasive plays complex have workpiece by its viscoelastic characteristics. In this study, the media for AMF was made by mixing viscoelastic polymer with alumina and silicon carbide abrasive respectively. As a result, alumina include media is also the experiments of deburring the inside burr of in order to analyse the deburring machinability of abrasive flow machining according to various machining parameters which were media flow rate extrusion pressure, passage gap, media viscosity, abrasive content, and abrasive grain size.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.214-220
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• 2009

The spindle is the main component in machine tools. The static and dynamic stiffness of the spindle directly affect the machining productivity and surface integrity of the workpiece. The static and dynamic stiffness of the spindle depend on the shaft size, bearing arrangement, bearing span length, and so on. Therefore, the selection of shaft size and bearing span length are important to improve the spindle stiffness. This paper presents the determination of shaft size and bearing span length in spindle design step. In order to select the optimal bearing and built-in motor locations with constraint conditions, the extreme vertices design was applied. The results show that extreme vertices design is usable for spindle design with design constraints.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10573-10576
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• 2015

Background: Accuracy in feature extraction is an important factor in image classification and retrieval. In this paper, a breast tissue density classification and image retrieval model is introduced for breast cancer detection based on thermographic images. The new method of thermographic image analysis for automated detection of high tumor risk areas, based on two-directional two-dimensional principal component analysis technique for feature extraction, and a support vector machine for thermographic image retrieval was tested on 400 images. The sensitivity and specificity of the model are 100% and 98%, respectively.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.223-228
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• 2009

We propose an on-line machine learning approach for object recognition, where new images are continuously added and the recognition decision is made without delay. Random forest (RF) classifier has been extensively used as a generative model for classification and regression applications. We extend this technique for the task of building incremental component-based detector. First we employ object descriptor model based on bag of covariance matrices, to represent an object region then run our on-line RF learner to select object descriptors and to learn an object classifier. Experiments of the object recognition are provided to verify the effectiveness of the proposed approach. Results demonstrate that the propose model yields in object recognition performance comparable to the benchmark standard RF, AdaBoost, and SVM classifiers.