• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.2
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• pp.119-131
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• 2024

Pulse-like ground motion can cause greater damage to structures than nonpulse-like ground motion. Currently, much research is being conducted to determine the presence or absence of velocity pulses and to quantify them from seismic-acceleration records. Existing ground motion is divided into far-field (FF) and near-fault ground motion, based on the distance of the measurement point from the fault. Near-fault ground motion is further classified into near-fault pulse-like (NFP) and near-fault nonpulse-like (NFNP) ground motion by quantifying the presence or absence of velocity pulses. For each ground motion group, 40 FF, 40 NFP, and 40 NFNP ground motions are selected; thus, 120 ground motions are used in the seismic analysis to assess the seismic fragility of sample bridges. Probabilistic seismic demand models (PSDMs) are created by evaluating the seismic responses of two types of sample bridges with lead-rubber and elastomeric rubber bearings using three groups of ground motions. Seismic fragility analysis is performed using the PSDM, and from these results, the effect of the presence or absence of seismic velocity pulses on the seismic fragility is evaluated. From the comparison results of the seismic fragility curve, the seismic fragility of NFP ground motion appears to be approximately three to five times greater than that of NFNP ground motion, according to the presence or absence of a velocity pulse of seismic waves. This means that the damage to the bridge is greater in the case of NFP ground motion than that in the case of NFNP ground motion.

• Information Systems Review
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• v.14 no.1
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• pp.37-65
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• 2012

This research aims to design and analyze a ubiquitous customer relationship management system based on near field communication which can be applied to stores in off-line environment. The existing customer relationship management system has been used mainly for stores in off-line environment to issue a royalty card, to stamp a seal on the purchase goods, and to manage the history of customers' visits and purchases. But, the existing system has two weaknesses; it makes difficult for a store manger not only to acquire a wealth of customer data but also to systematically manage the acquired data. In particular, the effectiveness and efficiency of the royalty card are questioned when a customer makes purchases in the store in that the customer frequently does not carry it or loses it. So, this research suggests a ubiquitous customer relationship management system where a tag for near field communications is attached to a store in off-line environment; a store manager can collect and manage easily customer's dada and customers can seamlessly acquire store's information. To do this, this research conducts the followings. First, we review the previous researches of customer relationship management to examine the concept of ubiquitous customer relationship management. Second, from the examination, we draw the factors to be considered in ubiquitous customer relationship management system based on near field communication. Third, we propose a scenario where the suggested system is used. Fourth, we analyze the participants' values and the process that will be used for the suggested system. Finally, we discuss the possibility of the application of this system to real business environment from various viewpoints.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.3 no.2
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• pp.32-38
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• 1985

The purpose of this paper is to develope the analytical calibration model and to present its efficiency and problems for elimination of systematic errors. For this purpose, lens distortion in close-range photogrammetry is analized. From the obtained accuracy of object space coordinates, it is found that the calibration model included only $K_1$ term is effective for metric camera, and film deformation has to be considered not only in non-metric camera but also in metric camera.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.7 no.2
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• pp.63-68
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• 1989

This study was to develope the methmatic prediction model of accuracy for the convergent photographs using nonmetric camera in close range photogrammetry. By analyzing positioning error on object distance and convergent angles, the validity of the new formulae for prediction of accuracy were proved. Rational design of camera systems and convergent angles according to accuracy demands in plane and height were developed using these formulae.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.49-60
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• 2010

The actual hysteretic behavior of structural elements and systems is smooth. Smooth hysteretic behavior is more representative of actual behavior than bi-linear or piece-wise linear stiffness degrading models. The strength reduction factor in seismic design is used to reduce the elastic strength demand to design levels. In this study, the effect of smoothness on the strength reduction factor is evaluated for several smooth hysteretic systems subjected to near-fault and far-fault earthquakes. For design purposes, a simple expression of the strength reduction factor considering hysteretic smoothness and earthquake characteristics, represented as near-fault and far-fault earthquakes, is proposed. The strength reduction factors calculated by the proposed simple formulation are more similar to the factors directly obtained from inelastic response spectrum analyses than those calculated by several existing formulas.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.231-238
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• 2022

In this paper, among short-range wireless communication technologies such as Beacon, Bluetooth, UWB (Ultra-wideband), ZigBee, NFC (Near Field Communication), Z-Wave, 6LoWPAN (IPv6 over Low power WPAN), D2D (Device to Device), etc., proposed an IoT service platform based on a beacon that can provide indoor positioning. And, a beacon-linked web server was designed by blocking indiscriminate beacon spam signals and applying REST web service technology with flexibility and scalability. Data accessibility between different devices was verified by testing the success rate of data transmission, the success rate of blocking beacon push, the success rate of IoT interlocking processing, the accuracy of location positioning, and the success rate of REST web service-based data processing. Through the designed IoT service platform, various proposals and research on short-distance-based business models and service platforms will be conducted in the future.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.5-14
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• 2010

To simulate two-dimensional plane-strain conditions in the laboratory model test, the side frictional resistance between the soil and thick glass or plastic sheet of the soil container should be reduced as much as possible. However, in fact this side friction cannot be removed completely. In this paper, the ground model simulated as a multi-sized aluminium rod mixture was introduced to get rid of the side frictional resistance and applied to the laboratory shear box test. In addition, an application of the close range photogrammetric technique to the shear box test was validated. As a result, it was found that a mean value of dilation angle from the close range photogrammetry was close to the dilation angle defined by the curve of shear strain vs. volumetric strain.

• Proceedings of the Acoustical Society of Korea Conference
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• 1985.10a
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• pp.50-53
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• 1985

한국연안에서 높게 보고되고 있는 수중소음의 소음원규명을 위하여 일차적으로 해상교통량에 그 초점을 맞추었다. 100Hz 부근의 소음은 이미 잘 알려진대로 선박에 기인함이 실험결과에서도 드러났지만, Wenz의 천해수중소음 모델 중 heavy shipping때보다 10-20dB 높게 관측되었다. 200Hz 이상에서의 소음은 선박분포에 따른 평균소음값에 큰 차이를 보이지 않았지만, 선박들의 거리 변화율이 심한 근거리에 다수의 선박이 분포해 있을 경우는 10분간격의 소음값이, 특히 1KHz 이상에서 최고 10dB까지 변화를 보였다. 이것은 이 주파수대역에서 연근해의 밀집해 있는 선박들이 하나의 소음원으로서의 역할을 함을 의미한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.212-215
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• 2000

본 논문은 근거리 차량간통신(IVC)에서 첨단차량도로시스템(AVHS)의 플래툰 주행에 적합한 One-Ray Rician 채널 모델을 적용하여 간섭신호에 강한 장점을 지닌 600Hz 밀리미터파를 에서 패킷 오율 특성을 분석하였다. 차후에 사용자의 욕구 증대에 따른 멀티미디어 서비스를 만족시키기 위해서 Convolution 부호화 기법과 MRC 다이버시티 수신 기법을 동시에 적용하였으며 그에 따른 DS-CDMA/QPSK System의 패킷 오율 특성을 분석하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.157-160
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• 2001

본 논문은 근거리에서의 차량간 통신에 밀리미터나 광전파를 분석하는데 효과적인 Ray Tracing방법을 도입하여 오율특성을 분석하였다. 분석환경으로는 간섭신호에 강한 장점을 지니며 산소흡수에 의한 감쇠가 크며 주파수 재사용효율이 좋은 60GHz 대역에서의 비트오율을 분석하였다. 전파모델로 지면반사파, 콘크리트벽에 의한 반사와 옆 도로를 달리는 차량에 의한 반사를 고려한 Two-Ray 라이시안 채널에서의 다중접속자에 의한 DS/CDMA 시스템의 비트오율특성을 분석하여 검토하였다.