• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.139-144
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• 2013

Various types of disease in the nervous and musculoskeletal system can change gait, and the gait analysis is very important in determining the progression of the disease. Most methods of analyzing gait are subject to high-priced equipment and spatial restrictions. This study used smart phone images and the walking track analysis program to make a comparative analysis with the existing gait analysis on the basis of the stride length measurements and the changes in the knee joint angle for walking. The test necessary to analyze gait was conducted in seven healthy men, and data about the angle of right and left knee joints and stride length were used to analyze gait. The gait analysis in this study obtained the similar results to the existing ones. The use of the methods suggested in this study will enable gait analysis to be made without high-priced equipment and spatial restrictions.

• Journal of Korea Water Resources Association
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• v.33 no.2
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• pp.181-193
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• 2000

This paper presents the flow and the suspended sediment movement over ripples for oscillatory flows. A new numerical model system is developed, and applied to a laboratory experimental condition of regular waves and a fictitious condition of irregular waves. The flow field is obtained from a programme proposed by Kim et. al.(1994), which is a modified version of SOLA based on SMAC scheme. The sub-model solves the continuity and Reynolds momentum equations in the x-z plane. The wave orbital velocities, shear stresses, and pressure are all reasonably reproduced by the model. The model results on the vertical velocity component show good agreement with the measurements. The suspended sediment transport sub-model is newly set up to solve the advection-diffusion equation of suspended sediment using a split method, and involving a special shear entrainment from the whole ripple surface. The calculated suspended sediment concentrations for regular waves show reasonable agreement with measurements at Deltaflume. The model results for random waves show that the suspended sediment concentration is higher than those for regular waves and that the sediment diffuses higher than for regular waves with the significant wave height and the peak wave period of the irregular waves.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.85-93
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• 2011

The width of sidewalk is one of the important factors constructing a pleasant pedestrian environment. The procedure for sidewalk width design based on the Level of Service is suggested in Korea Highway Capacity Manual. However, this manual does not give a difference between the sidewalk on the street with the passage of the subway, therefore, the different flow characteristic of these places is not appropriately reflected. Though the pedestrian flow in the subway encounters a frequent stop and go situation as like the platoon of vehicles, the similar condition is rarely observed at the urban streets. The new measure of LOS for sidewalk is in need. The study reviewed the prominent measure of LOS and carried out the outdoor experiment to evaluate the new measure. Particularity, GPS was used to collect the pedestrian foot path trajectory for the quantitative evaluation and the results from quantitative and qualitative are compared.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.459-467
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• 2011

Rehabilitation exercises must maintain a patient's interest and permit a quantitative evaluation of the rehabilitation. We have developed a haptic-device system. When users move a grip, the haptic device provides a virtual force that either assists the movement of their arm or working against it. To investigate the functional effect of this system in a rehabilitation program, we used for five subjects with motor-function disorders and measured the grip position, velocity, force exerted on the grip, and EMG activities during a reaching task of one subject. The accuracy of the grip position, velocity and trajectories patterns were similar for all the subjects. The results suggested that the EMG activities were improved by applying the virtual force to the grip. These results can be used for the development of rehabilitation programs and evaluation methods.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.68-80
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• 2016

This study proposes the traffic prediction and optimal traffic control system based on cell transmission model and genetic algorithm in cloud environment. The proposed prediction and control system consists of four parts. 1) Data preprocessing module detects and imputes the corrupted data and missing data points. 2) Data-driven traffic prediction module predicts the future traffic state using Multi-level K-Nearest Neighbor (MK-NN) Algorithm with stored historical data in SQL database. 3) Online traffic simulation module simulates the future traffic state in various situations including accident, road work, and extreme weather condition with predicted traffic data by MK-NN. 4) Optimal road control module produces the control strategy for large road network with cell transmission model and genetic algorithm. The results show that proposed system can effectively reduce the Vehicle Hours Traveled upto 60%.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.466-473
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• 2011

The buoyancy and initial momentum fluxes make near-field dominated by buoyant jet when thermal discharge releases underwater. In order to estimate prediction capabilities of those near-field phenomena, non-hydrostatic RANS applied CFD(Computational Fluid Dynamic) model was used. Condition of model was composed based on past laboratory experiments. Numerical simulations carried out for the horizontal buoyant jet in the stagnant flow and vertical buoyant jet into crossflow. The results of simulation are compared with the terms of trajectory and dilution rate of laboratory experiments and analytic model(CorJET) results. CFD model showed a good agreement with them. CFD model can be appropriate for assessment of submerged thermal discharge effect because CFD model can resolve the limitations of near-field analytic model and far-field quasi 3D hydrodynamic model. The accuracy and capability of the CFD model is reviewed in this study. If the computational efficiency get improved, CFD model can be widely applied for simulation of transport and diffusion of submerged thermal discharge.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.839-847
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• 2011

This paper proposes a new guidance law for increasing the lethality of munitions. The well known PNG (Proportional Navigation Guidance) is inadequate for the munitions because of some weaknesses. Even if the munition does not have the impact point error, the acceleration command is non zero because the line-of-sight changes at all times in flight. Therefore, we use a difference between a target and an impact point. This proposed guidance law is similar to PNG in the form, but this guidance law concentrates a correction rate of flight path angle instead of the LOS (Line of Sight) rate. The correction of flight path angle is defined as the amount of impact point error. This impact point error can be calculated by neural networks rapidly. Finally, we show that the simulation results prove the suitability of this law.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1094-1104
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• 2010

In the previous studies, the validation of numerical codes has been conducted based on the qualitative comparison of predicted ice shapes with experiments, which poses a significant limit on the systematic analysis of ice shapes due to the variation of meteorological conditions. In response to this, the numerical code has been quantitatively validated against available experiment for the ice accretion on cylinders and airfoils in the present study. Ice shapes accumulated on the bodies are systematically investigated with respect to various icing parameters. To this end, maximum thickness, heading direction and ice thickness are quantified and expressed in the polar coordinate system for the comparison with other numerical results. By applying the quantitative analysis, similar shapes are intuitively distinguished. The developed numerical code underestimates the ice accretion area and the ice thickness of lower surface. In order to improve the accuracy, further accurate aerodynamic solver is required for the water droplet trajectories.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.150-159
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• 2005

This paper addresses a voice personality transformation algorithm which makes one person's voices sound as if another person's voices. In the proposed method, one person's voices are represented by LPC cepstrum, pitch period and speaking rate, the appropriate transformation rules for each Parameter are constructed. The Gaussian Mixture Model (GMM) is used to model one speaker's LPC cepstrums and conditional probability is used to model the relationship between two speaker's LPC cepstrums. To obtain the parameters representing each probabilistic model. a Maximum Likelihood (ML) estimation method is employed. The transformed LPC cepstrums are obtained by using a Minimum Mean Square Error (MMSE) criterion. Pitch period and speaking rate are used as the parameters for prosody transformation, which is implemented by using the ratio of the average values. The proposed method reveals the superior performance to the previous VQ-based method in subjective measures including average cepstrum distance reduction ratio and likelihood increasing ratio. In subjective test. we obtained almost the same correct identification ratio as the previous method and we also confirmed that high qualify transformed speech is obtained, which is due to the smoothly evolving spectral contours over time.

• Communications of Mathematical Education
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• v.15
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• pp.273-280
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• 2003

1983년 말 중국 형주시 소재 강릉장가산 247호 묘에서 죽간의 형태로 출토된 ${\ulcorner}$산수소${\lrcorner}$ 는 그것이 엮어진 시점이 유휘의 ${\ulcorner}$구장산술${\lrcorner}$ 보아 최소한 450년 가량이나 거슬러 올라간다는 점에서 동야수학사의 기원을 크게 앞당기게 하는 막중한 의의를 지니는 문서가 아닐 수 없다. 그러나 석문 자체가 최근 들어와서야 겨우 공개되었을 뿐, 현재로서는 자료에 대한 평가와 내용 분석은 물론, 변역마저도 제대로 이루어지지 못한 상태에 있다. 이 글은 ${\ulcorner}$산수서${\lrcorner}$ 와 ${\ulcorner}$구장산술${\lrcorner}$ 의 내용을 배교하여 ${\ulcorner}$산수서${\lrcorner}$ 의 특징을 밝히는 동시에 동양수학의 초창기 발달의 궤적을 더듬어 보려는 시도이다. ${\ulcorner}$산수서${\lrcorner}$ 는 '상승(相乘)'에서 '이전(里田)'까지 이어지는 70개 제명(題名)하에 서술되어 있는데, 제명들은 주제를 나타내는 것과 산법을 나타내는 것을 혼재하는 것으로 나타난다. 내용 가운데에는 '여직(女織)', '우시(羽矢)', '소광(少廣)' 등이 문제처럼 ${\ulcorner}$구장산술${\lrcorner}$ 의 그것들과 기본적으로 같거나 유사한 것들이 다수 발견되어 고대수학 전통의 연속성을 엿볼 수 있게 하지만, 동시에 의료수가 문제인 '의(醫)'처럼 ${\ulcorner}$산수서${\lrcorner}$에서만 발견되는 것들도 더러 눈에 띈다. ${\ulcorner}$산수서${\lrcorner}$ 와 ${\ulcorner}$구장산술${\lrcorner}$ 사이에 이루어진 수학 발달은, 이를테면, 제급근 사이에 있어서 전자의 경우에는 $\sqrt{240}$을 $15\frac{15}{31}$로 계산한 데서도 드러나듯이 보간법에 의존한 반면, 후자의 경우에는 온답을 제시하는 데 하등의 어려움을 겪지 않았다는 차에서도 확인된다.