• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.29-42
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• 2005

Total 350 borehole profiles were selected from the database of borehole logs in Seoul, for the site-specific seismic evaluation at two 4km${\times}$4km plain areas. Equivalent-linear site response analyses for the selected 350 sites were conducted based on shear wave velocity (Vs) Profiles, which were determined from the N-Vs correlation established using borehole seismic testing results in the inland areas of Korea. Most sites were categorized as site classes C and D based on the mean Vs to 30 m in depth (Vs30) ranging from 250 to 550 m/s. The she periods of the plains in Seoul ranging between 0.1 and 0.4 sec were significantly lower than those of the western US, from which the site coefficients in Korea were derived. For plains in Seoul, the site coefficients, Fa's and Fv's specified in the Korean seismic design guide, underestimate the ground motion in short-period (0.1-0.5 sec) band and overestimate the ground motion in mid-period (0.4-2.0 sec) band, respectively, because ol the differences in the geotechnical conditions between Seoul and the western US, although the Fa's in several sites overestimate the motion due to the base Isolation effect resulted from the soft layer in soil deposit.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.6-13
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• 2012

As ocean resources in shallow water areas are being exhausted, deep sea development is becoming common these days. Therefore floating type offshore structures are more competitive than fixed type structures, and FPSO is the most popular one these days. FPSO's are generally operated in a specific region and positioned to meet mostly head or bow waves in order to reduce roll motions. However this makes these vessels more vulnerable to green water around the bow region, and therefore the bow shape must be properly designed to mitigate green water damage. In the present study, experimental results for three different FPSO bow shapes in regular head waves were analyzed and compared to each other. Also CFD computations were carried out as a sample validation case for the database built for CFD code validation.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.1
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• pp.35-42
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• 2020

In this paper, we propose a method to keep the robot at a distance of 30 to 45cm from the user in consideration of each individual's minimum area and inconvenience by using a 2D LiDAR sensor LDS-01 as the secondary sensor along with a QR code. First, the robot determines the brightness of the video and the presence of a QR code. If the light is bright and there is a QR code due to human's presence, the range of the 2D LiDAR sensor is set based on the position of the QR code in the captured image to find and follow the correct target. On the other hand, when the robot does not recognize the QR code due to the low light, the target is followed using a database that stores obstacles and human actions made before the experiment using only the 2D LiDAR sensor. As a result, our robot can follow the target person in four situations based on nine locations with seven types of motion.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.430-443
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• 2003

The objective of this paper is to evaluate most useful feature vector space using the angle, velocity and location features from gesture trajectory which extracted hand regions from consecutive input images and track them by connecting their positions. For this purpose, the gesture tracking algorithm using color and motion information is developed. The recognition module is a HMM model to adaptive time various data. The proposed algorithm was applied to a database containing 4,800 alphabetical handwriting gestures of 20 persons who was asked to draw his/her handwriting gestures five times for each of the 48 characters.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.452-455
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• 2005

In order to reproduce the traffic accident, It must save the data automatically which traffic accident 30 seconds before using black box. The Black Box can detect traffic crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time Belied before and after the accident. But it is not easy for the police to catch running away criminal. Because, criminal can remove proof if it is 2 hours or 3 hours at least. Therefore, in this paper, in order to catch a hit and run driver in the traffic accident road, it developed an structured Query Language Server and made parts database algorithm.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.62-69
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• 2015

Pressure change inside cabin as well as in tunnel has been calculated to assess the passenger pressure comfort of high-speed train. $C-STA^{TM}$, a CFD program based on axi-symmetric Navier-Stokes equation and Roe's FDS has been used to simulate the pressure change in tunnel during a high-speed train passing through it. To present the relative motion between the train and the tunnel, a modified patched grid scheme based on the structured grid system has been employed. The simulation program has been validated by comparing the simulation results with field measurements. Extensive parametric study has been conducted for various train speed, tunnel cross-sectional area and tunnel length to the pressure change in cabin. KTX-Sancheon(KTX2) high-speed train has been chosen for simulation and the train speed have been varied from 200 km/h to 375 km/h. The tunnel length has been varied from 300 m to 7.5 km and tunnel area from $50m^2$ to $120m^2$. Total 504 simulations have been conducted varying the parameters. Based on the database produced from the parametric simulations, minimum tunnel cross-sectional area has been surveyed for various train speeds based on Korean regulation on pressure change in cabin.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.51-59
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• 2016

This paper presents a method of DCT-based illuminant compensation to enhance the accuracy of face recognition under an illuminant change. The basis of the proposed method is that the illuminant is generally located in low-frequency components in the DCT domain. Therefore, the effect of the illuminant can be compensated by controlling the low-frequency components. Moreover, a directional high-order local pattern descriptor is used to detect robust features in the case of face motion. Experiments confirm the performance of the proposed algorithm got up to 95% when tested using a real database.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.2
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• pp.297-309
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• 1998

Numerical parameters have been developed to diagnose L4/L5 disc patients during repetitive flexions and extensions. Electromyography(EMG) has been used to define the muscle excitation and movement cycle in this study. Twenty healthy subjects and twenty L4/L5 disc patients were recruited for the experiment. The subjective pain levels of patients were recorded as $3.7{\pm}1.6$ according to visual analogue scale where 10 was the maximum pain level. Variance ratio of motion cycle was suggested as a new parameter to examine the consistency of the trunk movement. The results indicated that the temporal EMG pattern such as peak time difference between Quadriceps and Hamstrings, the duration of coexcitation between Erector spinae and Rectus abdominis muscle pairs showed a statistically significant difference between healthy subjects and patients. Variance ratio of External oblique and Internal oblique also showed a statistically significant difference. It is expected that those results could be used for diagnosis by building a database for various back pain patients and healthy subjects. This method can eventually help physicians for early diagnosis and prevention of low back disorders.

• Computers and Concrete
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• v.16 no.1
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• pp.99-123
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• 2015

In this study, structural vulnerability of reinforced concrete moment resisting frames (RC-MRFs) by considering the Iran-specific characteristics is investigated to manage the earthquake risk in terms of multicomponent seismic excitations. Low and medium rise RC-MRFs, which constitute approximately 80-90% of the total buildings stock in Iran, are focused in this fragility-based assessment. The seismic design of 3-12 story RC-MRFs are carried out according to the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800), and the analytical models are formed accordingly in open source nonlinear platforms. Frame structures are categorized in three subclasses according to the specific characteristics of construction practice and the observed seismic performance after major earthquakes in Iran. Both far and near fields' ground motions have been considered in the fragility estimation. An optimal intensity measure (IM) called Sa, avg and beta probability distribution were used to obtain reliable fragility-based database for earthquake damage and loss estimation of RC buildings stock in urban areas of Iran. Nonlinear incremental dynamic analyses by means of lumped-parameter based structural models have been simulated and performed to extract the fragility curves. Approximate confidence bounds are developed to represent the epistemic uncertainties inherent in the fragility estimations. Consequently, it's shown that including vertical ground motion in the analysis is highly recommended for reliable seismic assessment of RC buildings.

• Structural Engineering and Mechanics
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• v.59 no.4
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• pp.653-669
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• 2016

Recent earthquakes worldwide show that a significant portion of the earthquake shaking happens in the vertical direction. This phenomenon has raised significant interests to consider the vertical ground motion during the seismic design and assessment of the structures. Strong vertical ground motions can alter the axial forces in the columns, which might affect the shear capacity of reinforced concrete (RC) members. This is particularly important for non-ductile RC frames, which are very vulnerable to earthquake-induced collapse. This paper presents the detailed nonlinear dynamic analysis to quantify the collapse risk of non-ductile RC frame structures with varying heights. An array of non-ductile RC frame architype buildings located in Los Angeles, California were designed according to the 1967 uniform building code. The seismic responses of the architype buildings subjected to concurrent horizontal and vertical ground motions were analyzed. A comprehensive array of ground motions was selected from the PEER NGA-WEST2 and Iran Strong Motions Network database. Detailed nonlinear dynamic analyses were performed to quantify the collapse fragility curves and collapse margin ratios (CMRs) of the architype buildings. The results show that the vertical ground motions have significant impact on both the local and global responses of non-ductile RC moment frames. Hence, it is crucial to include the combined vertical and horizontal shaking during the seismic design and assessment of non-ductile RC moment frames.