• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.237-243
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• 2002

Now operating lines of many urban railway are currently in progress in the Seoul, but the inadequate consideration of links between different lines could create inconvenience as the public transport. This paper is studied about the connection service design of urban-railway convinced for other metropolis railways forms and propose the base pilot plan of the railway network linking system in Seoul Metropolis.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.612-614
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• 2014

급격한 가격변동에 대한 다양한 속성을 갖는 주가 기대치가 상이하여 기대치 가격을 중심으로 주가가 오르고 내리는 현상이 항상 발생한다. 이 현상은 Gibbs Effect와 매우 흡사한 성격을 갖고 있다. 장이 시작할때와 끝날때의 변동성을 수학적으로 모델링하고 이를 기반으로 한 거래기법을 연구 할 필요성을 갖게되어 시스템구현을 통해 매매기법을 분석하게 되었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.263-273
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• 2016

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_x$ emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and $NO_x$ emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.469-476
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• 2021

The purpose of this study is to explore the predictors of academic probation in college. Especially, this study focused on student engagement variables among the predictors of academic probation in college. Student engagement variables include hours of absence from class and numbers of log to LMS(Learning Management System) and in extracurricular program system during four weeks after the opening of a course and the numbers of faculty counseling. GPA(grade Point Average) is a dependent variable and GPA of prior semester is a control variable in this study. 17,261 student data were collected for the study. Linear regression model and logistic regression model analyses were conducted in the study. The finding showed that the hours of absence from class and numbers of log in extracurricular program system during four weeks after the opening of a course predicted academic achievement of college students. The result also indicated that hours of absence from class and numbers of log-ins to LMS(Learning Management System) and in extracurricular program system during four weeks after the opening of a course were the predictors of academic probation in college. This study will contribute to investigate indicators of students with low academic performance and to provide proper support for underachievers.

• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1145-1156
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• 2002

A method to measure the speed and distance of moving object is proposed using the stereo vision system. One of the most important factors for measuring the speed and distance of moving object is the accuracy of object tracking. Accordingly, the background image algorithm is adopted to track the rapidly moving object and the local opening operator algorithm is used to remove the shadow and noise of object. The extraction efficiency of moving object is improved by using the adaptive threshold algorithm independent to variation of brightness. Since the left and right central points are compensated, the more exact speed and distance of object can be measured. Using the background image algorithm and local opening operator algorithm, the computational processes are reduced and it is possible to achieve the real-time processing of the speed and distance of moving object. The simulation results show that background image algorithm can track the moving object more rapidly than any other algorithm. The application of adaptive threshold algorithm improved the extraction efficiency of the target by reducing the candidate areas. Since the central point of the target is compensated by using the binocular parallax, the error of measurement for the speed and distance of moving object is reduced. The error rate of measurement for the distance from the stereo camera to moving object and for the speed of moving object are 2.68% and 3.32%, respectively.

• Journal of Oral Medicine and Pain
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• v.35 no.2
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• pp.155-163
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• 2010

Dermatomyositis (DM) is an idiopathic inflammatory connective tissue disorder and a systemic autonomic immune disease which shows a progressive muscle weakness and characteristic rash. It is identified by a characteristic rash accompanying, or more often preceding muscle weakness. Pathognomonic skin lesions are a blue-purple discoloration on the upper eyelids with edema (heliotropic rash), a flat red rash on the face and upper trunk, and erythema of the knuckles with a raised violaceous scaly eruption (Gottron's papule). The myopathy represents inflammatory and degenerative changes primarily affecting proximal muscles. DM often involves GI tract and respiratory system with as risk of 15-25% internal malignancy. It's managed with sun protection since muscle weakness as well as a rash could be aggravated by sun exposure. Systemic corticosteroid is an initial therapy and other immunosuppressive agent has been used as alternatives. Facial muscles are unaffected and masticatory muscles are rarely affected in DM. We present trismus close to muscle contracture in a patient with DM. Therefore, it needs continuous mouth-opening exercise to prevent progressive muscle contracture and to ensure normal mouth opening.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.288-293
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• 2001

This paper presents the water-hammer effect due to the rapid opening and closing of isolation valve and thruster valve in the spacecraft propulsion system. The single propellant feed system was modeled to investigate the maximum peak pressure due to the water-hammer effect. The test parameters are tank supply pressure, shape and throat length of orifice and line length. Kerosene was used as the inert simulant propellant liquid instead of hydrazine. As downstream line length after isolation valve increased from 1.5 to 2.5m, the maximum line-filling water-hammer peak pressure decreased, but the average time interval between peak pressures increased. The maximum line-filling water-hammer peak pressure with orifice was lower than without orifice, and the maximum line-filling water-hammer peak pressure with orifice at the back of isolation valve was lower than with orifice in front of isolation valve. Without orifice, the maximum water-hammer peak pressure due to the rapid opening and closing of the thruster valve was about 126% of tank supply pressure. With orifice, it decreased. As orifice throat length increased, it decreased. The maximum water-hammer peak pressure due to the rapid closing of the thruster valve with converging-diverging orifice was lower than normal orifice. It was found that the orifice as a means of pressure drop was very effective to reduce the water hammer peak pressure at the thruster valve. The results of this study can be used for the design of spacecraft liquid propulsion feed system.

• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.41-48
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• 2008

The aim of this study is to present a graphical method in order to evaluate stages in shrinkage cracking. Firstly, the distribution of crack openings is established by sorting the openings of individual cracks in the soil cracking system. Secondly, it is normalized in a range of 0 to 1 to obtain the normalized crack opening distribution. Thirdly, three S-shape curve models introduced by Brooks and Corey(1964), Fredlund and Xing(1994) and van Genuchten(1980) are chosen to fit the normalized crack opening distribution using a curve fitting method. The accuracy of fitting which is described through fitting parameters by the van Genuchten equation is much higher than that by the Brooks and Corey equation and slightly higher than that by the Fredlund and Xing equation; thus the van Genuchten model is used. Finally, the stages of shrinkage cracking are graphically evaluated by drawing three separate straight lines corresponding to three linear parts of the fitted normalized crack opening distribution. The proposed method is tested with different sample thicknesses. The measured data are fitted by the selected model with the fairly high regression coefficient and small root mean square error. The results show graphically that shrinkage cracking comprises three stages; namely, primary, secondary and residual stages. Subsequently, the ranges of evaluated crack opening for each of these stages are presented.

• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.279-294
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• 2008

This study aimed to make an analysis of the occlusion in the state of muscle fatigue produced by excessive mouth opening and clenching during the dental treatment to control the dental pain and to evaluate the sensory nerve in the muscle pain state. Most of the reasons why patients visit the dental office result in pain-either conceivably the dental origin pain or the non-dental origin pain. The dental offices have many therapeutic actions to produce the masticatory muscle fatigue for the treatment. Dental treatment with long minutes of mouth opening can cause some headaches, masticatory muscle pain and mouth opening difficulties. Patients with mastication problems who visits a dental office to alleviate pain run against another unexpected pain with other aspects. This study uses T-scan II system(Tekscan Co., USA) for the evaluation on the occlusal pattern in the experimental muscle fatigue after clenching, opening the mouth excessively and chewing gum. The occlusal contact pattern is analyzed by the contact timing, namely first, intercuspal, maximum and end point of contact. This inspection was performed at frequencies of 2000Hz, 250 Hz and 5 Hz before and after each experimental muscle pain was produced to 24 subjects who had normal occlusion without the orthodontic treatment or a wide range of the prosthesis by using $neurometer^{\circledR}$ CPT/C(Neurotron, Inc. Baltimore, Maryland, USA). The measuring sites were mandibular nerve experimental muscle fatigue respectively. This study could obtain the following results after the assessment of occlusion and sensory nerve of the experimental muscle fatigue. 1. There were the fastest expression after the excessive mouth opening in muscle fatigue and after tooth clenching in muscle pain. In the visual analog scale that records the subjective level, there was the highest scale after the clenching in the muscle fatigue in jumping off the point of pain. 2. Tooth contact time, contact force, relative contact force on the point of the first contact had no difference, and there were decreases in the contact force after the excessive mouth opening on intercuspal position point, after the excessive mouth opening and the gum chewing on the point of the maximum, and in the contact time after all the experimental muscle fatigue state on the point of the end contact. 3. There was no statistic significance in the current perception threshold before and after the experimental muscle fatigue. 4. There was no significant difference in the contact number, the maximal contact number on the point of the first contact, and the contact number after the mouth opening and gum chewing on the point of the intercuspal position and the contact number after the experimental muscle fatigue on the maximum point, and showed significant decreases. In conclusion, it was found that the occlusal pattern can cause the changes on the case of the clinical muscle weakness by intra-external oral events. It was important that the sedulous attention to details is required during dental treatment in case of excessive mouth opening, mastication and clenching.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.3-5
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• 2005

The objective of this research was to develop a framework of the Soil Environment Information Management System (SEIMS). In this study, we found that the SEIMS needs to be consisted of three sub-systems (i.e., information input system, DB system, and opening to the public system), which is operated on the Web-GIS basis. Also, we suggested structure and detailed items for each sub-system which are acceptable under the basis of current legal and institutional system. Furthermore, we made several suggestions for future-oriented system. Further researches need to be pursued for developing efficiently the SEIMS, such as 1) DB standards for the SEIMS, 2) guidelines for each cleanup phase, 3) improvement of the SEIMS for groundwater quality, and 4) integrated SEIMS for both soil and groundwater system.