• 한국정밀공학회지
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• 제29권10호
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• pp.1056-1061
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• 2012

FEM analysis is essential to shorten the development time and reduce the cost for developing high-performance machine tools. Mount joint parts play important role to ensure static and dynamic stability of machine tools. This paper suggests a computational modeling of mount joint part of machine tools. MATRIX27 element of ANSYS is adopted to model mount joint parts. MATRIX27 allows the definition of stiffness and damping matrices in matrix form. The matrix is assumed to relate two nodes, each with six degrees of freedom per node. Stiffness and damping values of commercial mount products are measured to build a database for FEM analysis. Jack mounts with rubber pad are exemplified in this paper. The database extracted from the experiments is also used to estimate of stiffness and damping of untested mounts. FEM analysis of machine tools system with the suggested mount computational model is performed. Static and dynamic results prove the feasibility of the suggested mount model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.501-502
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• 2012

• 한국생산제조학회지
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• 제24권1호
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• pp.7-14
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• 2015

The machine tools builders are trying to improve the efficiency and performance of the machine tools. The electro-mechanical driven broaching machine has many advantages such as lower noisy operating, higher energy efficiency, and smaller space of installation. This paper presents the structural and mechanical development of an electro-mechanical driven broaching machine that is replaced for traditional hydraulic one. The servo motor, ball screw and roller linear guide are used instead of hydraulic cylinder and translation frictional sliding guides. The simulation method based on FEM was applied to analyze the stress, deformation of the machine for static analysis. The dynamic analysis was carried out for verifying and assessing the mechanical behavior of the developed broaching machine. This work helps broaching machine developer make a better product at the early design stage with lower cost and development time.

• 한국정밀공학회지
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• 제28권4호
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• pp.422-426
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• 2011

The spindle system is very important unit for the product accuracy in machine tools. A spindle system is designed by using the angular contact ceramic ball bearings, built-in motor, oil-air lubrication method and oil jacket cooling method. The static and dynamic analysis and stiffness evaluation of 45,000rpm spindle for machine tool has been investigated. Using a finite element method, we obtained some analyzed a static and dynamic characteristics of a spindle, such as natural frequency, harmonic analysis and we got the value of compliance through it. We evaluated stiffness by taking the inverse this value. A 45,000rpm spindle is successfully developed using the results.

• Tribology and Lubricants
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• 제6권1호
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• pp.57-67
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• 1990

For increasing the performance of Machine tools, the improvement of the static and dynamic characteristics of spindle bearing is important. In this paper are the static characteristics, the pressure distribution, friction force and outlet flow rate, and the dynamic characteristics stiffness and damping coefficient, of a cylindrical hydrostatic journal bearing with multi oil pockets are analyzed.

• 한국생산제조학회지
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• 제20권3호
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• pp.298-303
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• 2011

Recently, demand on machine tools has been increased because the machine and automobile industry is booming. Therefore, the machine tools need to have a high accuracy and productivity. To build a high precision machine tool and increase its productivity, structural analysis needs to be carried out for vibration and stiffness of the machine tool before its detail design. However, it is the fact that many manufacturers of machine tools depend on their know-how about design experience. Therefore, in this paper, the static and dynamic analysis is carried out for evaluating a horizontal CNC lathe and then, applied to its detail design. It is positive that the analysis can lead to reduction of design time and improvement of the quality of the lathe as its design proceeds.

• Journal of Information Processing Systems
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• 제16권4호
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• pp.882-895
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• 2020

The amount of malware increases exponentially every day and poses a threat to networks and operating systems. Most new malware is a variant of existing malware. It is difficult to deal with numerous malware variants since they bypass the existing signature-based malware detection method. Thus, research on automated methods of detecting and processing variant malware has been continuously conducted. This report proposes a method of extracting feature data from files and detecting malware using machine learning. Feature data were extracted from 7,000 malware and 3,000 benign files using static and dynamic malware analysis tools. A malware classification model was constructed using multiple DNN, XGBoost, and RandomForest layers and the performance was analyzed. The proposed method achieved up to 96.3% accuracy.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.390-395
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• 2003

Moving flexible structures such as transfer systems in press machine, crane, working table of machine tools have vibration problems because of starting, feeding and stopping. An analysis method is suggested and experimentally studied in order to solve a vibration problem of a moving flexible structure. In this method, the concepts of substructure synthesis method and semi-static displacement including rigid body mode were used. Total deformation of a structure was assumed to be composed of quasi-static and dynamic components. Experimental results from an elementary model of a transfer feeder showed good agreements with computational results.

• 한국정밀공학회지
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• 제24권2호
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• pp.127-133
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• 2007

The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. To improve the competition power of price to quality, spindle design is very important. Because it possesses over 10 percent of machine tool's price. The latest machine tools have rotational frequency and excellent about might and precision cutting. So it requires static and dynamic strength in the load aspect. In conclusion, the deformation of the spindle end have to extremely small displacement in static and dynamic load. In this study, On the assumption that the bearings that are supporting 24,000rpm high-speed spindle are selected in the most optimum condition, the natural frequency and deformation of the spindle end is obtained by FEM mode analysis. The Taguchi Method was used to draw optimized condition of bearing position and it's stiffness.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.985-988
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• 2002

The Spindle-]fearing System is very important unit for geometrical accuracy in machine tools. To improve effectively the weak point of spindle system, it is necessary that the contribution ratio of spindle core parts to static and dynamic stiffness is clarified. In this paper, static contribution ratio of core parts is calculated by overlapping static deformation of basic spindle design with one flexible parts. The dynamic contribution ratio for natural frequency and dynamic deformation at spindle end is obtained by calculating correlation between original and basic spindle deformation, by curve fitting with regressive method. It is proved the validity of estimation result is correct.