• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1102-1105
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• 2008

In this paper, the prediction method of internal temperature for high strength concrete members at high temperature is presented. Finite element method is employed to facilitate thermal analysis for any position of member. In case of water evaporates inside the concrete member by high temperature, the evaporation heat that absorb surrounding temperature is occurred. This effect of the evaporation heat is applied. And the model equations of the material characteristics of high strength concrete by high temperature are proposed. To demonstrate the validity of this numerical procedure, the prediction by the proposed algorithm is compared with the test results of other researchers. The proposed algorithm is good agreement with experimental results including the phenomenon that temperature by the evaporation heat is lost.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.39-46
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• 2019

Human mobility estimation plays a key factor in a lot of promising applications including location-based recommendation systems, urban planning, and disease outbreak control. We study the human mobility estimation problem in the case where recent locations of a person-of-interest are unknown. Since matrix decomposition is used to perform latent semantic analysis of multi-dimensional data, we propose a human location estimation algorithm based on matrix factorization to reconstruct the human movement patterns through the use of information of persons with correlated movements. Specifically, the optimization problem which minimizes the difference between the reconstructed and actual movement data is first formulated. Then, the gradient descent algorithm is applied to adjust parameters which contribute to reconstructed mobility data. The experiment results show that the proposed framework can be used for the prediction of human location and achieves higher predictive accuracy than a baseline model.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.5
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• pp.372-382
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• 2002

As the most of dentofacial deformity patients indicated to orthognathic surgery have strong desire for esthetic improvement as well as functional improvement, ideal esthetic evaluation should be made at surgical prediction. Lateral cephalographs has been commonly used for surgical prediction, however, remarkable discrepancy between esthetic viewpoint by simple looking and analysis on lateral cephalographs often found on evaluation of sagittal position of the upper and lower jaws especially in cases of mandibular prognathism of Koreans. In these cases, we have been employed Esthetic NaP(ENaP)-line for corrective evaluation and ideal surgical prediction on lateral cephalographs, but the efficacy of ENaP-line has not been evaluated. This is a study on efficacy of ENaP-line for orthognathic surgery of Korean mandibular prognathism. 170 Korean patients who had been diagnosed as mandibular prognathism and planned for orthognathic surgery at Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University during last 10 years are studied. The obtained results are as followings; among 170 patients of mandibular prognathism, 132 patients(77.6%) had not discrepancy in evaluation of sagittal position of the maxilla between cephalometric and esthetic evaluation(they are classified as Group I), however, 38 patients(22.4%) had definite discrepancy(they are classified as Group II). ENaP-line was employed in all cephalometric analysis of Group II. The proportions of male and female were similar in both Groups. Sixteen vertical reference lines perpendicular to 16 horizontal reference lines were obtained as followings; Each of the representative degree of ${\angle}SN/AFH$, ${\angle}SN/CFH$ and ${\angle}AFH/CFH$ obtained at Group I was applied to SN plane, AFH plane and CFH plane of Group II each other, and so 16 horizontal reference lines could be obtained individually according to each of the applied degree to each plane. And then their reliability to coincide with ENaP-line of Group II was evaluated. A vertical reference line perpendicular to a horizontal line made by application of the representative degree of ${\angle}$AFH/CFH in Group I to AFH line in Group II had the most highest coincidence with ENaP-line of Group II, however, its agreement was 42% in male and 47% in female. From this results, the rest of them should be determined their corrective jaw position definitely depend on

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.227-235
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• 2018

The aim of this study is to predict the sensitivity of motion sickness (MS) using pattern of cardinal gaze position (CGP) before experiencing the virtual reality (VR) content. Twenty volunteers of both genders (8 females, mean age $28.42{\pm}3.17$) participated in this experiment. They was required to measure the pattern of CGP for 5 minute, and then watched VR content for 15 minute. After watching VR content, subjective experience for MS reported from participants using by 'Simulator Sickness Questionnaire (SSQ)'. Statistical significance between CGP and SSQ score were confirmed using Pearson correlation analysis and independent t-test, and prediction model was extracted from multiple regression model. PCPA & PCPR indicators from CGP revealed significantly difference and strong or moderate positive correlation with SSQ score. Extracted prediction model was tested using correlation coefficient and mean error, SSQ score between subjective rating and prediction model showed strong positive correlation and low difference.

• Journal of Astronomy and Space Sciences
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• v.27 no.1
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• pp.31-42
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• 2010

We developed a computer program to predict solar interference period. To calculate Sun's position, we used DE406 ephemerides and Earth ellipsoid model. The Sun's position error is smaller than 10arcsec. For the verification of the calculation, we used TU media ground station on Seongsu-dong, and MBSAT geostationary communication satellite. We analysis errors, due to satellite perturbation and antenna align. The time error due to antenna align has -35 to +16 seconds at $0.1^{\circ}$, and -27 to +41 seconds at $0.25^{\circ}$. The time errors derived by satellite perturbation has 30 to 60 seconds.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.57-65
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• 1997

In this study, a cutting force in the Ball-end milling process is calculated using Z-map. Z-map can describe any type of cutting area resulting from the previous cutting geometry and cutting condition. Cutting edge of a ball-end mill is divided into infinitesimal cutting edge elements and the position of the ele- ment is projected to the cutter plane normal to the Z axis. Also the cutting area in the cutter plane is obtained by using the Z-map. Comparing this projected position with cutting area, it can be determined whether it engages in the cutting. The cutting force can be calculated by numerical integration of cutting force acting on the engaged cutting edge elements. A series of experiments such as contouring and upward/downward ramp cutting was performed to verify the calculated cutting force.

• The KSFM Journal of Fluid Machinery
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• v.4 no.3 s.12
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• pp.29-38
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• 2001

The floating ring seal has the ability of minimizing clearance without the rubbing phenomenon. It is often used in the turbo pump units of liquid rocket engines due to its superior leakage performance. The exact prediction of the lock-up position of the floating ring, the leakage performance, and the rotordynamic coefficients of the seal is necessary to evaluate the rotordynamic performance of the turbo pump unit. The governing equations(which are based on the Bulk-flow Model) we solved by the Fast Fourier Transform method. The lock-up position, leakage flow rate, and rotordynamic coefficients are evaluated according to the geometric parameters of the floating ring seal.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.28-33
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• 1992

The paper describes a new mean specific cutting pressure model in order to improve the accuracy of prediction of cutting force for face milling. The new mean specific cutting pressure model produces a mean specific cutting pressure and coefficients applied to existing cutting model not by traditional method but by considering intermittence and variation of chip width according to insert cutting position to take into cutter geometry machining condition and width of workpiece, and considering a mean measure force according to spindle eccentricity and mean measure force according to spindle eccentricity and insert initial position errors.. The simulated forces in X, Y, Z directions resulted from the simulated cutting model and the new cutting model are compared with measured forces in the time end frequency domains. The simulated forces in the time and frequency domains. The simulated forces resulted from the new cutting model have a good degreement with measured forces in comparison with these resulted from the existing cutting model

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.232-242
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• 1996

In this study, the simulation program for the prediction of volumetric efficiency of the internal combustion engine by the resonator has been developed, when the resonator is mounted on the intake system of 4-cycle SI engines for the improvement of volumetric efficiency. The experimental work has also been carried out for the verification of the program, and it is found that the result of calculation by the simulation program fits qualitatively well with that of experiment. To get the optimal mounting position of resonator on the intake system, the influence of the variation of dimensions of resonator such as neck length, volume and neck diameter were examined by the numerical calculation of the program in advance and the results were compared with the experiments. It is found that the position which is departed 150cm from plenum chamber is better than any other positions, and the average amount of the increase of volumetric efficiency is about 2∼3%

• Journal of Environmental Science International
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• v.19 no.6
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• pp.755-759
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• 2010

Each four polycyclic aromatic hydrocarbons (PAHs) was reacted with OH radical at $1.5{\AA}$ distance by CAChe MOPAC 2000 program. These results were compared to those reported experimental results. Reaction positions of all four PAHs corresponded with predicted positions in which ${\Delta}$E(HOMO-LUMO) was approximately 4.7. Finally oxygen of OH radical combined with PAH and quinone form of products were produced. These results indicate that the proposed determining the ${\Delta}$E(HOMO-LUMO) can be effectively applied to predict reaction position of recalcitrant compounds such as dioxins, PCBs, POPs, and etc.