• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.67-76
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• 2012

This paper proposes an efficient method that helps a visually impaired person to detect a pavement borderline. A pedestrian is equipped with a camera so that the front view of a natural scene is captured. Our approach analyzes the captured image and detects the borderline of a pavement in a very robust manner. Our approach performs the task in two steps. In a first step, our approach detects a vanishing point and vanishing lines by applying an edge operator. The edge operator is designed to take a threshold value adaptively so that it can handle a dynamic environment robustly. The second step is to determine the borderlines of a pavement based on vanishing lines detected in the first step. It analyzes the vanishing lines to form VRays that confines the pavement only. The VRays segments out the pavement region in a radial manner. We compared our approach against Canny edge detector. Experimental results show that our approach detects borderlines of a pavement very accurately in various situations.

• Journal of the Korea Society of Computer and Information
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• v.17 no.10
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• pp.137-143
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• 2012

The learners using learning content through the smart devices can access to the Internet from anytime and anywhere. However, with the rapid increase of learning content on the Web, it will be time-consuming for learners to find contents they really want to and need to study. Therefore, e-learning systems should not only provide flexible content delivery, but support adaptive harmonizing fusion content. The harmonizing fusion content it is a very important in fusion e-learning service. The representative method to provide synchronization between fusion content is a provide absolute time value between of the contents. However, this method is occurs a problem transferring time delay. Also, to enter an absolute time value for the duration of the each content is several problems arise. In this paper introduces a new smart e-smart service support the harmonizing media based technology to create synchronized learning presentation.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.47-52
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• 2011

This paper collect sleep environment data of bedroom to sleeping, and analyzing the relationship between conditions with obtained data and sleep. We provide the optimal sleep environment of individual by extracting the simulation model based on it. The experiments was using temperature/humidity sensor(SHT11) and ambient light sensors(GL5507). For extraction of tossing and turning, we use difference image method in motion extraction from video. In addition, the information of weight can affect to sleep, it was entered such as ratio of fatigue, drinking, empty stomach. As a result, we are able to extract the optimal sleep environment. The future, we will try to improve to help to lead more pleasant daily life providing proper indoor environment changes depending on the situation even a partial of organic ubiquitous living environments such as eating, work ete. as well as certain sleep circumstances.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.6
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• pp.25-32
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• 2002

In the seismic designing of bridges, the pile foundation of bridge piers generally have been modeled to have a fixed end for its convenience and conservative designing. The fixed-end assumption, however, produces very conservative results in terms of the pier forces. Therefore, many other design methods are evolved to consider the flexibility of the pile foundation. In this study, the response spectrum analysis was performed for a bridge pier having a pile foundation. The shear force, moment, and displacement, which occurred at the pier column under an earthquake loading, were compared to analyze the effects of the modeling method, soil condition and the input earthquake response spectrum. In most cases, the fixed-end model gives larger design forces than flexible foundation models. However, when a long period earthquake is applied to the bridge pier on a soft clay foundation, it is found that the flexible foundation models give larger design forces than the fixed-end model. In the end, the reliability of several flexible foundation models was verified by comparing their results with those of a numerical analysis that considers the soil-structure interaction phenomenon in a rigorous manner.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.1-7
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• 2003

This paper presents a novel hybrid time-frequency-domain method for nonlinear soil-structure interaction(SSI) analysis. It employs, in a practical manner, a computer code for equivalent linear SSI analysis and a general-purpose nonlinear finite element program. The proposed method first (calculates dynamic responses on a truncated finite element boundary utilizing an equivalent linear SSI program in the frequency domain. Then, a general purpose nonlinear finite element program is employed to analyze the nonlinear SSI problem in the time domain, in which boundary conditions at the truncated boundary are imposed with the responses calculated in the previous frequency domain SSI analysis, In order to validate the proposed method, seismic response analyses are carried out for a 2-D underground subway station in a multi-layered half-space, For the analyses, a equivalent linear SSI code KIESSI-2D is coupled to ANSYS program. The numerical results indicate that the proposed methodology can be a viable solution for nonlinear SSI problems.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1345-1351
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• 2010

First, In this essay we research about secondary source unit(SIV)180KVA is install on VVVF direct subways for using Filter Capacitor(FC) maintenance & limit of use. Vehicle's extendly use and congestly at load for Catenary voltage and load change about output change and in SIV unit there are important device named GTO Thyristor, Power Transistor Module device become short and it often happen. We analysis the fault cause and there are effects and we know the secondary source unit in filter capacitor FC1~4 input harmonic distortion component's filtering don't do correctly so we study the capacitor extend use for the component change and the outside condition by slow property changed happen and we check before and when its fault, its difficult to measure. Finally, In this research we care for this reason and we study about capacitor maintenance through control and measure ways improvement and capacitor's life spans limit of use.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.313-336
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• 2007

Unlike a conventional railway system, a high-speed rail system experiences various aerodynamic problems in tunnel sections. Trains running at a high speed in a small tunnel, when compared with the open field, face significant air pressure, resulting in reduced operating stability and fast change in pressure inside the tunnel. These phenomena further cause some unexpected problems such as the passengers onboard feeling an aural discomfort and an impulsive noise at the tunnel exit. To solve these problems, this paper introduces analysis of aerodynamic characteristics for determination of tunnel cross section. The optimum cross-section that satisfies the criteria of aural discomfort was reviewed through lots of numerical simulation analysis. Also, the pressure inside the passenger car of a train operating on Kyungbu HSR line was measured, and the pressure inside the tunnel and the micro-pressure waves at tunnel exit were measured at Hwashin 5 Tunnel. At the same time, a test of train operation model was performed and then the measurement results and test results were compared to verify that various parameters used as input conditions for the numerical simulations were appropriate.

• Nuclear Engineering and Technology
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• v.23 no.3
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• pp.316-320
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• 1991

The Core Operating Limit Supervisory System (COLSS) is digital computer based on-line monitoring system that is designed to assist the operator in monitoring of the Limiting Conditions for Operation. A current COLSS calculates axial power distribution based on in-core detector signals using 5th order Fourier series method. It was found that the 5th elder Fourier series method was not accurate for certain axial power shapes, especially saddle power shapes, resulting in thermal margin decrease. A cubic spline synthesis was applied to the COLSS in order to improve the axial power distribution monitoring for the various axial power shapes. The results showed that the cubic spline synthesis simulated more accurately the axial power shapes, up to 5% in RMS errors, compared to those of the Fourier series.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.280-285
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• 2007

Based on the multimode fiber taper, a mode size converter for effective optical beam coupling between laser and optical fiber or between the two different optical fibers has been proposed and demonstrated. The device has a multimode input end and a single mode output end. The influence of various parameters, including device structure and launching conditions, on the coupling efficiency has been theoretically analyzed. The theoretical results revealed that the gaussian beam can be coupled into a single mode fiber without considerable insertion loss. The proposed multimode fiber taper has been fabricated using heating and pulling equipment incorporating two micro-torches. Experimental results showed that an optical beam with $50\;{\mu}m$ of large beam size was effectively coupled into single mode fiber through the multimode fiber taper. The insertion loss of the device was 1.3 dB.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.15-20
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• 2006

In this study the flow characteristics of smoke and heat on a bank type platform of the underground subway station are studied numerically by considering two different emergency operation modes. Effects of the natural flow through the tunnel and the stair ways are considered in the numerical simulations by using the measured velocities presented in Part I as the boundary condition. Distributions of heat, smoke, visible range and toxic gas on the platform are analysed for different smoke extraction flowrates corresponding to the two different emergency operation modes. The numerical results show that the extraction flowrate affects the smoke control performance significantly by improving the smoke removal performance as the extraction flowrate is increased.