• Journal of ILASS-Korea
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• v.13 no.2
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• pp.65-72
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• 2008

It is recognized that alternative fuel such as dimethyl ether (DME) has better combustion polluting characteristics than diesel fuel, even though the cetane number of DME is almost the same as that of diesel. Characteristics of DME spray were observed experimentally under various ambient conditions using a constant volume chamber and a common-rail injection system. N-dodecane and LPG fuel sprays were also observed under same conditions of DME spray. Using spray images from backlight scattering and Mie scattering, characteristics of fuel sprays such as penetration and spray volume were visualized and quantitatively measured. The measurements showed that the penetration of early period decreased remarkably, because evaporation of alternative fuels became prosperous by the influence of flash boiling phenomenon under the condition of the low temperature and pressure compared with n-dodecane. The penetration of DME and LPG spray received the influence of temperature more largely in comparison with low density, because the specific surface area increased by atomizing in high density.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.41-46
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• 1987

A new control scheme is developed to achieve fast and accurate decoupled tracking for an n-Joint robotic manipulator In the Presence of disturbances and unknown Parameter variations. The control system is designed so that a new type of state trajectories called sliding mode may exist in a phase plane. In order to remove the reaching Phase and high frequency chattering phenomenon which ate the common shortcomings of variable structure control(VSC) scheme, this paper presents the new switching line which is composed of three segments and the continuous control law which is derived from the existence condition of a sliding mode. The Proposed methods in this Paper are applied to a 3-Joint robotic manipulator as a numerical example-The digital simulation results which are compared with those of typical VSC scheme show the validity of accurate tracking capability and robust Performance of the system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.265-266
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• 2008

The interest on harmonics which is one of the matters related with power quality problem is not limited in only the system where the large scale industrial load is connected. The harmonics phenomenon not only causes the malfunction of devices, but also lowers the energy efficiency of power system. This paper focuses on the harmonic analysis process to establish the harmonic mitigation method, considering the harmonics distortion as a major cause to reduce the energy efficiency of a skyscraper. A system diagram of building is modelled with PSCAD simulator. Based on the harmonic analysis results of it, the electrical locations with the high priority to install the mitigating devices are selected. Finally, the result of PSCAD simulations and the site-measured data are compared, verifying that they reach a common conclusion.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.512-517
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• 2011

This study is intended for validation of numerical modeling of a residential building which is made to simulate a phenomenon of fire extension from floor to floor. A common residential building which has the area of 80m2 each floor and some combustibles were chosen for numerical modeling. The combustible models were verified through comparing results of numerical simulations and real fire tests. For computational analysis, the Fire Dynamics Simulator was used with Large Eddy Simulation model for turbulence. Consequently, fire-intensity was well predicted and flash-over of rooms were successfully estimated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.91-99
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• 1998

This paper presents a methodology for identifying the cutter runout geometry in end milling process. Cutter runout is common but undesirable phenomenon in multi-tooth machining because it introduces variable chip loading to insert which results in a accelerated tool wear. amplification of force variation and hence enlargement vibration amplitude From understanding of chip load change kinematics, the analytical cutting force convolution model was formulated as the angular domain convolution model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the local cutting forces and the chip width density of the cutter. Experimental study is presented to validate the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance and surface quality for industrial application.

• Imaging Science in Dentistry
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• v.34 no.4
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• pp.195-197
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• 2004

Metastatic tumors to the jawbones are an infrequent but not rare phenomenon. The most common site of distant primary tumor metastasis to the jaw bones is the breast. The clinical signs and symptoms, and radiographic appearance of these lesions can be quite variable. In this report, an invasive ductal carcinoma of the breast that metastasized to the whole mandible is presented. The patient's medical history revealed that she had undergone a modified radical mastectomy on the right breast eight years ago.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.215-219
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• 2005

Hepatocellular carcinoma is one of the most common cancer worldwide, primarily affecting those in regions with a high prevalence of viral hepatitis. However, the metastasis of hepatocellular carcinoma to the oral cavity is a rare phenomenon. This report presents a case of metastatic hepatocellular carcinoma in the left mandibular angle and ramus region of a 62-year-old man. Panoramic radiograph revealed an ill-defined radiolucent lesion extending from the retained root of the mandibular left second molar into the ascending ramus. The lesion had irregular and ill-defined margins.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.649-654
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• 2009

In this paper, we propose "InFra-VC", an interactive Fractal viewer on virtual reality system. Fractal impresses us very much and is expected to model some natural phenomenon effectively. Therefore, their visualization is necessary for us to study their beauty as well as structure. InFra-VC can represents a cutting plane of the fractal figure, so that the user can see and enjoy its internal structure. Moving position of the cutting surface, we can easily understand its internal structure. Additionally, InFra-VC can store situation as VRML format file at any time. This feature enables us to see the structure by a VRML viewer on common PC.

• Archives of design research
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• v.14 no.2
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• pp.127-136
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• 2001

The aim of this study is to examine and compare Koreans and Japanese creativities in advertising. It was to analyze empirically their creativities appreciated in 200 TV commercials broadcasted between 1992 and 1998. The content analysis, was a useful process, provided very important clues for comparative analysis. Many difference were found in the examined TV commercials in Korea and Japan. It showed major difference in ways in which the level of noise, the using of cuts, social space, camera work, etc. except preference of jingle, colors, elements of tradition. The most distinctive difference is that the Japanese TV commercials deal with atmosphere than the Korean commercials. This result may help to explain a common social phenomenon of not losing the original culture in each society, as a result of "international acculturation" and the subsequent "indigenization by adaptive change"

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.80-88
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• 2009

As well as the development of the measurement of service quality, various kinds of service measurements are also being developed. Especially the mobile telecommunication service being representative to the mobile telecommunication company would be the mostly developed area. Its development can be understood along with the development of the telecommunication companies as well as cellular companies, not only the service alone. It is a differentiated phenomenon in the current research, such as the organic influence between the service quality and product. Of course there are such products placed on sale and enjoyed the common service, but at present there is another case that the product is on the market exclusively with the mobile company in here. This paper make a suggestion about process to improve how to make a new product include of customers view. So. This paper was using the QFD and AHP.