• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.147-155
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• 1999

The film thickness and shape of elastohydrodynamic lubrication is measured by optical interferometer, which is the most precise method for EHL film measurement. However the interpretation of the image pattern from optical viscometer is not easy for two-dimensional shape. A newly developed method of image processing makes it possible to evaluate the film thickness and shape in every point of contact region with two dimensional aspects. In this study, we captured film shape of EHL film from the monochromatic incident light with the Image processing method, which uses phase shift method, and obtained the image analysis method for gray level image in order to qualitatively evaluate film shapes.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.9
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• pp.761-767
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• 2005

There exists a structural limit of 2WS cars that drivers would not like simultaneously to follow the desired path and attenuate moments resulting from disturbances because lateral acceleration and yaw rate are coupled inherently. In order to overcome the limit, the 4WS cars that have rear wheel steering as an additional input have been introduced. But the 4WS cars have disadvantages that much cost is required due to structural alteration, it is difficult to be used to the driving circumstances and tire performances are not efficient in nonlinear or large lateral acceleration ranges. Therefore, it is proposed that, in this paper, a robust controller is easy to apply to 2WS cars by using direct yaw moment, decouples lateral acceleration from yaw motion and is robust against disturbances and uncertainties of system parameters, and thus the proposed control method has the advantages of 4WS cars which can be achieved in 2WS cars.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.857-867
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• 1990

Sine CAM structure is regular structure as that of RAM of PLA, CAM generator program is easy to implement. This program outputs CAM layout in the form of CIF(Caltech Intermediate Format) and graphic display program is debugging or displaying CAM generator output, which are implemented on PC/AT with MS C(5.0) graphic library and C language. CIF parser is programmed with YACC(Yet Another Compiler Compiler) and LEX (Lexical Analyzer) in order to flat the CIF data. For the purposed of plotting the layout output using ROLAND XY plotter is developed. By combining these program described above, from CIF generation to layout plotting can be executed on pull-down menu according to user's option.

• The Journal of Information Technology
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• v.8 no.4
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• pp.27-42
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• 2005

In recent days a glowing consensus has been emerging among Korean manufacturing companies that e-Supply Chain Management. The companies also realize that the introduction of e-SCM is not an easy undertaking, and it faces a lot of difficult obstacles. Study was called e-SCM in order a small paper let our country Small and Medium industry understand importance of e-SCM, and to be utilized, Both understanding about e-SCM of College students and investigation executed a parallelism. The companies, Which actually do some e-business and are keen to do so in the future, have a better chance to introduce e-SCM.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.797-802
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• 2011

I assessed the B($a$)P content from the Ginseng extract, Red ginseng extract, and Ssangwha extract which have high viscosities. It wasn't easy to extract oil from these samples, consequently measuring of B($a$)P was difficult. In order to know the exact detecting contents, I injected standard material of B($a$)P to the above extractions and pre-treated for measurement but it was also difficult to measure of contents exactly. To improve of detecting method, I removed mucinous materials using a 85% phosphoric acid solution or 10% citric acid solution and then processed continuously with $60^{\circ}C$ hot water. The analysis revealed that extracting the samples contained B($a$)P determined the rate of each 70%, 55%, 67% could increase. As a result the detecting method of B($a$)P contents could be improved.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1642-1646
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• 2011

One of the rolling stocks, low floor tram is recognized as the important alternative to improve traffic and environmental problems. There are many advantages of tram transportation system. It has, especially, low construction costs and easy accessibility. Trams operate with vehicles on roadways. The bogie configuration including traction motor of tramcar is different from that of conventional electric trains because tram has lower floor than train. In these reasons, the traction motors of tramcar are exposed to dusts, water and so on. Therefore, motors are designed by totally enclosed type. In this paper, we explain the design and test of totally enclosed traction motor for tramcar. Characteristic tests and temperature-rising tests were carried out in order to predict the performance of motor and the maximum temperature of coil.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1035-1040
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• 2011

In this paper we deal with a kinetic performance test system using hydraulic cylinder. It is possible to measure only current using the conventional electro-mechanical actuator when the bogie is in the process of the tilting. This makes impossible to measure the force acting on the tilting actuator. In order to overcome this problem a kinetic performance test system using hydraulic cylinder is proposed. The proposed system provide easy kinetic evaluation for the tilting mechanism and evaluation for the co-relation between load acting on the tilting actuator and the moving displacement(strock) of the tilting actuator.

• Journal of Power Electronics
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• v.13 no.2
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• pp.264-274
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• 2013

A new sensorless position estimation method for switched reluctance motor (SRM) drives is presented in this paper. This method uses the change of the slope of the phase inductance to detect the aligned position. Since the aligned positions for successive electrical cycle of each phase are apart by a fixed mechanical angle $45^{\circ}$ in the case of 12/8 SRM, the speed of the machine can be calculated to estimate the rotor position. Since no prior knowledge of motor parameters is required, the method is easy for implementation without adding any additional hardware or memory. In order to verify the validity of this technique, effects such as changes in the advanced angle and phase lacking faults are examined. In addition, an inductance threshold based sensorless starting scheme is also proposed. Experimental results demonstrate the validity of the proposed method.

• Journal of Sensor Science and Technology
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• v.22 no.1
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• pp.44-48
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• 2013

For a successful commercialization of microbolometer, it is required to develop a robust package including thermal stabilizing mechanism. In order to regulate the temperature within some operating range, thermoelectric cooler is generally used but it's not easy to model the whole package due to the coupled physics nature of thermoelectric cooler. In this paper, SPICE-compatible modeling methodology of a microbolometer package is presented, whose steady-state results matched well with FEM results at the maximum difference of 5.95%. Although the time constant difference was considerable as 15.7%, it can be offset by the quite short simulation time compared to FEM simulation. The developed model was also proven to be useful for designing the thermal stabilizer through parametric and transient analyses under the various working conditions.

• Journal of the Ergonomics Society of Korea
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• v.27 no.2
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• pp.59-65
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• 2008

Product usability consists of many attributes such as learnability, efficiency, memorability, and so on. In particular, learnability is one of the most important attributes in product usability. Therefore, many people consider the primary criterion for a good user interface to be the degree to which it is easy to learn. Learnability represents the degree of how much can easily learn the usage of a product. It concerns the features of the interactive system that allow novice users to understand how to use it initially and then how to attain a maximal level of performance. In this study, we studied on the application of learning curve to evaluate product learnability. In order to validate the applicability, we carried out simple experiment using mobile phone. We got task completion times through the experiment and predicted the times using learning curve model. And then, we compared prediction times to task completion times. Finally, we identified that learning curve could apply to predict and compare product learnability.