• 한국정밀공학회지
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• 제10권2호
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• pp.161-169
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• 1993

The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is presented in order to predict the dynamic cutting force from the static cutting data. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coefficient which can be determined from the cutting mechanics. The stability analysis is carried out by a two degree of freedom system. The chatter experiments are conducted by exciting the cutting tool with an impact hammer during an orthogonal cutting. A good agreement is shown between the stability limits predicted by theory and the critical width of cut determined by experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.1016-1020
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• 2000

In this study, a structural characteristics analysis system for motor-integrated high-speed spindle systems, “SpindleX”, is developed based on the Timoshenko theory and the multi-layered finite element method. Since “SpindleX” has the various analysis modules related to static deflection analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically and quantitatively the design and evaluation processes of spindle system under the windows GUI environment. Also, to enhance the user-friendliness, “SpindleX” possesses the various additional functions such as the DXF file interface for auto-importing the shape and geometric data of spindle system from the DXF file, the bearing database for auto-importing the mechanical properties and geometric data of bearing by the bearing number, and the graphical visualization for certificating the imported and analysed data of spindle system.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.231-236
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• 2001

The goal of multiphase optimization of machine structure is to obtain 1) light weight, 2) statically and dynamically rigid structure. The entire optimization process is carried out in two phases. In the first phase, multiple optimization problem with two objective functions is treated using pareto genetic algorithm. Two objective functions are weight of the structure, and static compliance. In the second phase, maximum receptance is minimized using genetic algorithm. The method is applied to design of quill type machine structure with back column.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.726-733
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• 2000

In this article, we introduce a practical case study of the structural design improvement for a vertical machining center. During test operations, it have experienced excessive deflections and vibrations due to the fluctuating forces generated by the ball-screw thrust motor. At first we did investigate where and how much deflections and vibrations had been brought about on it. Next we made some possible structural design alternatives. It is a matter of course to compare finite element static and dynamic analysis results of both the original design and alternatives. Fortunately we have been able to find out a good one among those alternatives.

• 한국기계연구소 소보
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• 통권18호
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• pp.21-27
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• 1988

In this study, a series of experiments and analyses are performed to estimate the static characteristics of hydrostatic journal bearing such as load capacity, pressure change in each recess, eccentricity of spindle, etc. The experiments are carried out for a multi-recess type journal bearing with capillary restrictor. The Finite Element Method(FEM) is used for the analyses. The predicted load capacity under the condition of stationary or eccentric ratio of bellow 0.2 of the spindle shows excellent agreement with the measured. But, with an increase of the eccentric ratio when the spindle is rotating, the predicted load capacity is largely estimated than the measured. It seems that the difference is mainly caused among others from the fact that the effect of oil-viscosity variation due to the temperature change in the bearing is not introduced into the analyses. The analysis method proposed to estimate the static characteristics of hydrostatic journal bearing is considered to be very reliable since the predicted results are overall in good agreement with the measured.

• 한국기계가공학회지
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• 제11권4호
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• pp.13-19
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• 2012

There are many dynamic properties in measured end-milling force. So, it is difficult to predict the real static property of end-milling force. Also the behavior of end-milling force is very complex to predict with the measured one. To extract the static property from measured force, it must be filtered and its problem is closely related to a de-noising one. Also this paper presents alternative de-noising method of end-milling force using wavelet filter bank, based on the wavelet transform and its inverse one. In this paper, by comparing the measured force and its wavelet filtered one, the fundamental end-milling force property after wavelet transform is well reviewed and analyzed. This result of wavelet filtering with filter bank shows the static force of end-milling which has severe dynamic properties occurring in entry and exit state of edge emersion into the workpiece.

• 정보보호학회논문지
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• 제30권6호
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• pp.1131-1139
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• 2020

소스코드에 대한 정적 분석은 광범위한 소스코드에 대해서 잔존하는 보안약점을 찾는 것으로 정적 분석 도구를 활용하여 점검을 하고, 그 결과에 대해서 정적 분석 전문가가 정탐 및 오탐 분석을 한다. 이 과정에서 분석양이 많고 오탐의 비율이 높아 많은 시간과 노력이 들어가게 되어 효율적으로 분석하는 방안이 요구되고 있다. 또한 전문가들은 정·오탐 분석을 할 때 결함이 발생한 라인의 소스코드만 보고 분석을 하는 경우는 드물다. 결함의 유형에 따라서 주변의 소스코드를 같이 분석하고 최종 분석 결과를 내리게 된다. 이러한 정적 분석 도구를 사용하여 전문가가 정·오탐을 판별하는 어려움을 해결하기 위해서 본 논문에서는 정적 분석 도구가 찾은 보안약점이 정탐인지 아닌지를 전문가가 아닌 인공지능을 통해 판별하는 방법을 제안한다. 또한 이러한 기계학습에 사용되는 학습 데이터(결함주변 소스코드)의 크기가 성능에 어떤 영향을 미치는지 실험을 통해 최적의 크기를 확인하였다. 이 결과를 통해 정적 분석 후 정·오탐을 분류하는 정적 분석 전문가의 업무에 도움을 줄 것으로 기대한다.

• Computers and Concrete
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• 제28권5호
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• pp.465-478
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• 2021

On the premise of ensuring that the static performance of the concrete spreader is met, the first-order natural frequency of the concrete spreader is increased, and the weight of the main beam is reduced. ANSYS is used as an analysis tool to perform modal analysis on the concrete spreader. The natural frequency, mode shape and modal test verification will be obtained to ensure the accuracy of finite element model analysis. Using the ANSYS designxplorer module, the size of the main beam is set, and the response surface model between the parameter variables and the optimization objective is established according to the experimental design points. Screening algorithm and MOGA algorithm are used to multi-optimize the stress, first-order natural frequency and girder weight, and the optimal solution is obtained by comparison. The results of modal analysis are consistent with those of the experiment, and a set of optimal solutions is obtained through the optimization algorithm. The optimal solution obtained can meet the purpose of increasing the first-order natural frequency of the concrete spreader and reducing the weight of the main beam under the premise of ensuring the overall dynamic and static performance of the concrete spreader.

• 한국컴퓨터정보학회논문지
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• 제28권2호
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• pp.1-7
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• 2023

본 논문에서는 MIPS 아키택처 기반 펌웨어의 정적분석 환경을 구축하기 위한 방법으로, $gp 레지스터와 페이지 입상도를 활용한 베이스 주소 후보군 선정 방식을 제안한다. 해당 연구는 기존 연구의 귀납적 추론을 통한 베이스 주소 후보군 선정 방식의 단점인 베이스 주소 탐색 시간 단축을 위한 방법으로 기존 베이스 주소 후보군 선정방식 내 $gp 레지스터를 탐색의 기준점을 바탕으로 페이지 단위의 탐색을 수행하는 방법을 제시한다. 이후, 제시된 방법을 바탕으로 베이스 주소탐색 도구를 구현 및 정적분석 환경구축을 통해 대상 도구의 타당성을 증명하고자 한다. 본 논문에서 제시된 방법은 기존 귀납적 추론을 통한 후보군 선정 방안보다 속도 면에서 더 우수함을 나타낸다.

• 한국안전학회지
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• 제25권3호
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• pp.91-99
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• 2010

In this study, the advanced numerical algorithm is developed which can performed the static and dynamic stochastic finite element analysis by considering the effect of uncertainties included in the member stiffness of steel cable-stayed bridges and seismic load. After conducting the linear and nonlinear initial shape analysis, the advanced numerical algorithm is the assessment tool which can performed structural the response analysis considering the static linearity and non-linearity of before or after induced intial tensile force, and examined the reliability assessment more efficiently. The verification of the developed numerical algorithm is evaluated by analyzing the regression analysis and coefficient of correlation using the direct monte carlo simulation. Also, the dynamic response characteristic and coefficient of variation of the steel cable-stayed bridge is calculated by considering the uncertainty of random variables using the developed numerical algorithm. In addition, the quantitative structural safety of the steel cable-stayed bridges is evaluated by conducting the reliability assessment based upon the dynamic stochastic finite element analysis result.