• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.13-17
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• 2007

It is very insecure to treat a butane can for cooking out of door. The human injury from the accidents of butane cans has been getting increased 1.5 times yearly since 2003. In this context, the Institute of Gas Technology Training in Korea Gas Safety Corporation carries out explosion experiment to make trainees to take all possible measures to ensure safe management of gas in the field by fully recognizing the hazards of gas explosion accidents. This study intends to examine the influence of such explosion experiments on the trainees witnessing nearby. The GEN exposed to the active students participating in the experiment away from 25 meters from the explosion site was 57.94 dB and the GEN to the passive students not participating away from 50 meters was 51.92 dB. According to Weber-Fechner's law for the lower value than 65 dB which is the environmental standard, it is safe from the place 15 meter far from the explosion place. The environmental standard of offices is 50 dB, and it is lower than the environmental standard if the office is 65 meter far from the explosion place.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.103-110
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• 2010

This paper presents the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method and approximation modeling method with Radial Basis Function (RBF) neural network structure. The complex tool holder is used for holding a (milling/drilling) tool of a machine tool. The engineering problem of complex tool holder results from the twisting of spindle of tool holder. For this purpose, we present the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method (specifically a module of $iSight^{(R)}$ FD-3.1) and approximation modeling method with Radial Basis Function (RBF) (another module of $iSight^{(R)}$ FD-3.1) neural network structure

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.30-36
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• 2014

Many different cells types have been found to be highly sensitive to mechanical force imposed by their surroundings. The cellular response to external mechanical forces has very important effects on numerous biological phenomena. In spite of its importance in biological processes, the cell adhesion force remains difficult to measure quantitatively at the cellular level. In this paper, to enhance quantitative measurements of cell adhesive interactions, a new attaching system and a method in which a glass bead can be attached to an AFM cantilever was designed and fabricated, and the degree of range displacement was controlled in the system. In an experiment, the movement of the stage in the attaching system and the attaching process were measured. The effectiveness of this system was confirmed as well in the experiment. In addition, through a commercial AFM system, the spring constant of the modified AFM probe could be measured.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.123-129
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• 2022

Quartz (SiO2) has high abrasion and heat resistances and excellent chemical and mechanical properties; therefore, it is used in various industries, such as machinery, chemistry, optics, and medicine. Quartz is a high-hardness and brittle material and is classified as the topmost difficult-to-cut material, which is because of the cracking or chipping at the edge during processing. Corner wear, such as cracks and chippings that occur during cutting, is a major cause for the deterioration in the machining quality. Therefore, many researchers are investigating various techniques to process quartz effectively. However, owing to the mechanical properties of quartz, most studies have been conducted on grinding, micromachining, and microdrilling. Few studies have been conducted on quartz processing. The purpose of this study was to analyze the machining characteristics according to the machining factors during the slot machining of quartz using a cubic boron nitride (CBN) tool and to select the optimal machining conditions using the Taguchi method. The machining experiment was performed considering three process variables: the spindle speed, feed rate, and depth of cut. The cutting force and surface roughness were analyzed according to the processing conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.529-532
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• 2012

This paper presents the system modeling, analysis, and controller design and implementation with a inverted pendulum system in order to test robust algorithm for sweeping machine. The balancing of an inverted pendulum by moving pendulum robot like as 'segway' along a horizontal track is a classic problem in the area of control. This paper will describe two methods to swing a pendulum attached to a cart from an initial downwards position to an upright position and maintain that state. The results of real experiment show that the proposed control system has superior performance for following a reference command at certain initial conditions.

• Design & Manufacturing
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• v.6 no.2
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• pp.84-89
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• 2012

In recent years, technology of press plastic working having made remarkable progress. We can say this because it facilitates mass production and have superior performances in machining speed and equivalency of quality than other processing methods. In characteristics of press plastic working, mold manufacturing according to characteristics of each product should be preceded before processing and it has a great influence on machining speed and quality of products and etc according to manufacturing method. Therefore, mold design technology is a critical technology in press plastic working. There are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment.

• Journal of Power System Engineering
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• v.19 no.5
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• pp.17-24
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• 2015

In this paper, the development of an air cushion transporter has been studied. To do this, theoretical analysis is introduced to design the equipment and computational fluid dynamics is also conducted. Design of an air cushion transporter for heavy load carriage is completed and a prototype is manufactured. Through the analysis and experiment of the developed the prototype, it can be known that the developed transporter can levitate the load of about 1 ton at the applied pressure of 0.2 MPa and the maximum lifting height at this condition is 17mm.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.295-301
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• 2012

This paper deals with the design of robust DSMC (Discrete-Time Sliding Mode Control) scheme in order to overcome system uncertainty in steering system with mechanically joined structure. The proposed control scheme is one of robust control schemes based on system dynamics. Therefore, system dynamics required is not obtained from physical law but SCM (Signal Compression Method) through experiment in order to avoid complicate mathematical development and save time. However, SCM has a shortcoming that is the limitation of with $2^{nd}$ order linear model which does not include the dynamic of high-frequency band. Thus, considering system uncertainty, DSMC is designed. In addition, to reduce the chattering problem of DSMC, DSMC is derived from the reaching law and the Lyapunov stability condition. It is found that the proposed control scheme has robustness in spite of the perturbation of system uncertainty through computer simulation.

• Journal of Animal Environmental Science
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• v.8 no.3
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• pp.165-170
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• 2002

This study was carried out to measure the 3D-distance of a cow model teat for an application possibility on Robotic Milking System(RMS). A teat recognition algorithm was made to find 3D-distance of the model by using Gonzalrez's theory. Some of the results are as follows. 1 . In the distance measurement experiment on the test board, as the measured length, and the length between the center of image surface and the measured image point became longer, their error values increased. 2. The model teat was installed and measured the error value at the random position. The error value of X and Y coordinates was less than 5㎜, and that of Z coordinates was less than 20㎜. The error value increased as the distance of camera's increased. 3. The equation for distance information acquirement was satisfied with obtaining accurate distance that was necessary for a milking robot to trace teats, A teat recognition algorithm was recognized well four model cow teats. It's processing time was about 1 second. It appeared that a teat recognition algorithm could be used to determine the 3D-distance of the cow teat to develop a RMS.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.97-103
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• 2013

A new precision positioning mechanism for stage was been developed by Displacement Magnification Device(DMD) in this paper. The DMD was composed of the beam and multilayer piezoelectric actuators. The theoretical and experimental analysis of DMD to enlarge displacement more then 50times were discussed. And the 2-axis stage by using displacement amplification apparatus was added in the new DMD, and it was able to do it through finite element analysis and experiment. As the results, the magnification of DMD can be obtained about $100{mu}m$ displacement to the 10V input voltage($1.5{mu}m$). And the about 50nm of linearity error in the $30{mu}m$ measurement range and 20times of the amplification in displacement can be measured. In addition, the experimental results are confirmed the possibility of millimeter displacement characteristics and correspond to finite element analysis results.