• Journal of Korea Multimedia Society
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• v.25 no.1
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• pp.10-28
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• 2022

In this paper, we present an entry-level COVID-19 stand-alone digitial signage player (CoSiP) which performs not only conventional digital signage functionalities but also fever detection, face mask wearing detection, and KI-pass QR code checking. The overall design of CoSiP is proposed, and implementation of a temperature checking algorithm using a low cost thermal sensor is elaborately presented. Through experiments over datasets and against a developed CoSiP device, it is shown that the fever detection, face mask wearing detection, KI-pass QR code checking as well as signage functionalities of the proposed CoSiP work properly and reliably.

• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.847-860
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• 2020

The 2-pass DInSAR (Differential Interferometric SAR) processing steps for DEM generation consist of the co-registration of SAR image pair, interferogram generation, phase unwrapping, calculation of DEM errors, and geocoding, etc. It requires complicated steps, and the accuracy of data processing at each step affects the performance of the finally generated DEM. In this study, we developed an improved method for enhancing the performance of the DEM generation method based on the 2-pass DInSAR technique of TanDEM-X bistatic SAR images was developed. The developed DEM generation method is a method that can significantly reduce both the DEM error in the unwrapped phase image and that may occur during geocoding step. The performance analysis of the developed algorithm was performed by comparing the vertical accuracy (Root Mean Square Error, RMSE) between the existing method and the newly proposed method using the ground control point (GCP) generated from GPS survey. The vertical accuracy of the DInSAR-based DEM generated without correction for the unwrapped phase error and geocoding error is 39.617 m. However, the vertical accuracy of the DEM generated through the proposed method is 2.346 m. It was confirmed that the DEM accuracy was improved through the proposed correction method. Through the proposed 2-pass DInSAR-based DEM generation method, the SRTM DEM error observed by DInSAR was compensated for the SRTM 30 m DEM (vertical accuracy 5.567 m) used as a reference. Through this, it was possible to finally create a DEM with improved spatial resolution of about 5 times and vertical accuracy of about 2.4 times. In addition, the spatial resolution of the DEM generated through the proposed method was matched with the SRTM 30 m DEM and the TanDEM-X 90m DEM, and the vertical accuracy was compared. As a result, it was confirmed that the vertical accuracy was improved by about 1.7 and 1.6 times, respectively, and more accurate DEM generation was possible with the proposed method. If the method derived in this study is used to continuously update the DEM for regions with frequent morphological changes, it will be possible to update the DEM effectively in a short time at low cost.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.52-65
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• 2016

The electronic toll collection system(ETCS), is globally used in about 40 countries. In Korea, the Korea Expressway Corporation led the nationwide introduction of the ETC system in 2007 under the brand name of the Hi-pass. Since then, Hi-pass, with its rate of average daily use reaching about 70%, has become an essential facility in Korean expressways. To identify users' perception on Hi-pass (satisfaction, preference, etc.), this study conducted a Modified Importance-Performance Analysis (M-IPA). With this, this study attempted to identify the kind of efforts necessary to enhance current Hi-pass users' convenience and satisfaction. According to the result of M-IPA, the items including "non-stop payment" and "toll discount" are identified as key items that require further improvement. For improvement in the "non-stop payment" item, operations of Hi-pass toll booths appropriate for the demand for Hi-pass use and the selection of Hi-pass booths' locations in consideration of entry and exit lanes need to be improved. In addition, with regard to the "toll discount" item, although toll discount is currently provided to Hi-pass users, thus, PR thereof will have to be strengthened. It is expected that this study will be used as basic data to devise methods of enhancing Hi-pass usage through improvement of Hi-pass users' satisfaction.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.799-807
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• 2016

The aim of this study is to determine and propose the by-pass rainwater sewer system in order to reduce the urban floodplain from the locality heavy rain every year during the dry season and the sinkholes in the city as well as the shortage of groundwaters due to extreme hot weather condition and urban heat island phenomenon. Heavy rain occurs more than the years of heavy rainfall probability, comparison between the place where uses the existing pipes and connect the sewer system with by-pass rain permeability and without expanding sewer pipe replacement at intersection of Gangnam station 3.07 ha at Gangnam-gu, Seoul Metropolitan area, it indicates that average of 27 million KRW (44%) maintenance cost savings and maintain existing sewer system without any other countermeasures. For the city flooded reduction, by-pass rainwater permeable rainwater pipe multiplying the probability the number of years during summer season and increase the water flow capacity during spring and fall when a small amount of rain that, it also contribute to the total amount of underground water secured through the by-pass penetration.

• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.164-168
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• 2016

A dual-band through-the-wall imaging radar receiver for a frequency-modulated continuous-wave radar system was designed and fabricated. The operating frequency bands of the receiver are S-band (2-4 GHz) and X-band (8-12 GHz). If the target is behind a wall, wall-reflected waves are rejected by a reconfigurable $G_m-C$ high-pass filter. The filter is designed using a high-order admittance synthesis method, and consists of transconductor circuits and capacitors. The cutoff frequency of the filter can be tuned by changing the reference current. The receiver system is fabricated on a printed circuit board using commercial devices. Measurements show 44.3 dB gain and 3.7 dB noise figure for the S-band input, and 58 dB gain and 3.02 dB noise figure for the X-band input. The cutoff frequency of the filter can be tuned from 0.7 MHz to 2.4 MHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2943-2948
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• 2015

Run 3D reconstruction using a single camera, based on the information, we are advancing research on driving assistance apparatus or can be informed how to pass the obstacle existing ahead the driver. As a result depth information falls but it is possible to provide information that can pass through an obstacle on the straight. For 3D reconstruction by measuring the internal parameters, it calculates the Fundamental matrix and matching to find the feature points obtained by executing the triangulation on the basis of this. When the through experiments try to confirm the results, the depth information is present error information in the X and Y axes which can determine whether or not to pass through an obstacle has reliability.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.185-189
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• 2005

This paper focuses on the design for Rx/Tx switch module of GSM(global standard mobile) band, characterization of a miniature, low power and dual-band implementation of the front-end switch module with low-pass filer And the effort to make agreement between the simulated design and the measured data for these solutions takes the place through accumulated design and manufacturing data library. We present the design, modeling and measurement of switch module integrating GSM Rx/Tx switching circuit and LPF(low pass filter) on a LTCC(low temperature co-fired ceramic) substrate. For GSM application, insertion and return loss of the low pass filter designed was less than 0.3 dB which was less than 12.7 dB at 900 MHz. The LTCC switch module contained 10 embedded passives and 3 surface mount components integrated on 4.6$\times$4.8$\times$1.2 mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module measured at 900 MHz was 11 dB. In both of the design approach yielded excellent agreement between measured and simulated results.

• Journal of Welding and Joining
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• v.11 no.3
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• pp.34-47
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• 1993

Finite element models were developed for thermal and residual stress analysis for the specific welding problems. They were used to evaluate the effectiveness of the various welding heat input models, such as ramp heat input function and lumped pass models. Through the parametric studies, thermal-mechanical modeling sensitivity to the ramp function and lumping techniques was determined by comparing the predicted results with experimental data. The kinetics for residual stress formation during welding can be developed by iteration of various proposed mechanisms in the parametric study. A ramp heat input function was developed to gradually apply the heat flux with variable amplitude to the model. This model was used to avoid numerical convergence problems due to an instantaneous increase in temperature near the fusion zone. Additionally, it enables the model to include the effect of a moving arc in a two-dimensional plane. The ramp function takes into account the variation in the out of plane energy flow in a 2-D model as the arc approaches, travels across, and departs from each plane under investigation. A lumped pass model was developed to reduce the computation cost in the analysis of multipass welds. Several weld passes were assumed as one lumped pass in this model. Recommendations were provided about ramp lumping techniques and the optimum number of weld passes that can be combined into a single thermal input.

• Journal of the Korean Society of Radiology
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• v.8 no.6
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• pp.301-307
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• 2014

In this study, an image acquired by the DSA(Digital Subtraction Angiography) system that is configured to configure the algorithm for high pass filtering algorithm experiments to improve the quality of angiography methods proposed. high pass filter is a high-frequency components pass through the filter, blocking low-frequency components. Part of the boundary line and contour of the organ corresponds to the high-frequency component is a high-frequency component of a medical image. Therefore, the high pass filter is also used for detection of the boundary line, but is also used for the high frequency enhancement. It was able to be analyzed by the proposed algorithm, to improve the quality of the angiography. Found out that the expression of the target site stand out clearly. The quality of the DSA system proposed in the wrong diagnosis software can be used to reduce, it is possible to develop and will further improve the accuracy of the treatment.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.709-720
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• 1998

In order to study the distribution of welding residual stress through the plate thickness. experiment and analysis of fillet welding details were carried out. Especially, a residual stress in the weld root part of T-joint fillet weld whose measurement was difficult up to now was measured. By using the heat input and the number of the weld layers as parameters, the distribution of the 3-dimensional residual stress was investigated. As a result, we can say that with increasing the heat input, the residual stress in the weld toe and weld root barely changes. But, the area of the tensile residual stress became wide. Then, comparing a single pass with multi-pass weld method, it was found that the residual stress decreased more in multi-pass than in single pass. Moreover, it was found the thing that the area of tensile residual stress by multi-pass is lower than that by single-pass in the near weld part.