• 콘크리트학회논문집
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• 제17권3호
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• pp.323-328
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• 2005

교량구조물은 설계당시에 설계기준에서 요구하는 구조적 안전성을 확보할 수 있도록 설계 및 가설된다. 그러나 시간이 지날수록 중차량이나 교통환경변화 등 여러 원인에 의해 손상을 받게되고 문제가 있는 교량은 결국에는 교체 또는 개선이 필요하게 된다. 본 논문에서는 기존 연구자료를 검토하여 교량의 유지관리조치를 수행하기 위한 의사결정과정에 영향을 미치는 인자를 파악하였고, 이를 이용하여 우선순위 산정 알고리즘을 제안하였다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.469-472
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• 2008

In general, structures in service gradually lose original performance according to time due to initial defects in design and construction, or exposure to unfavorable external conditions such as repeated loading or deteriorating environment, and in extreme cases, may collapse in large disaster. Therefore, in order to maintain the serviceability of structures at optimal level, advanced structure measuring system which can inform optimal time point and method of maintenance is required in addition to accurate prediction of residual life the structure by periodic inspection. To guarantee the safety level of bridge structure and to prevent from disaster, the integration of safety network for bridge structures are needed. Therefore in this study, to enhance the effectiveness of safety network for bridge, the connection methodologies between safety network and pre-installed bridge monitoring system are investigated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.1030-1050
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• 2021

The edges with "bridge characteristic" play the role of connecting the communication between regions in power optical cable network. To solve the problem of mining edges with "bridge characteristic" in provincial power optical cable network, the complex power optical cable network model is constructed. Firstly, to measure the generated potential energy of all nodes in n-level neighborhood local structure for one edge, the n-level neighborhood local structure topological potential is designed. And the minimum connected chain attenuation is designed to measure the attenuation degree caused by substituted edges. On the basis of that, the minimum connected chain attenuation topological potential based measurement is designed. By using the designed measurement, a bridge-edges mining algorithm is proposed to mine edges with "bridge characteristic". The experiments are conducted on the physical topology of the power optical cable network in Jilin Province. Compared with that of other three typical methods, the network efficiency and connectivity of the proposed method are decreased by 3.58% and 28.79% on average respectively. And the proposed method can not only mine optical cable connection with typical "bridge characteristic" but also can mine optical cables without obvious characteristics of city or voltage, but it have "bridge characteristic" in the topology structure.

• Journal of Power Electronics
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• 제13권2호
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• pp.296-303
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• 2013

This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.

• Smart Structures and Systems
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• 제11권5호
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• pp.453-476
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• 2013

DuraMote is a remote sensing system developed for the "NIST TIP project: next generation SCADA for prevention and mitigation of water system infrastructure disaster". It is designed for supervisory control and data acquisition (SCADA) of ruptures in water pipes. Micro-electro mechanical (MEMS) accelerometers, which record the vibration of the pipe wall, are used detect the ruptures. However, the performance of Duramote cannot be verified directly on a water distribution system because it lacks an acceptable recordable level of ambient vibration. Instead, a long-span cable-stayed bridge is an ideal test-bed to validate the accuracy, the reliability, and the robustness of DuraMote because the bridge has an acceptable level of ambient vibration. The acceleration data recorded on the bridge were used to identify the modal properties of the structure and to verify the performance of DuraMote. During the test period, the bridge was subjected to heavy rain, wind, and a typhoon but the system demonstrates its robustness and durability.

• Smart Structures and Systems
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• 제31권5호
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• pp.501-516
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• 2023

Dynamic irregularity and acceleration of bridges subjected to high-speed trains provide crucial information for comprehensive evaluation of the health state of under-track structures. This paper proposes a novel approach for real-time estimation of vertical track dynamic irregularity and bridge acceleration using deep generative adversarial network (GAN) and vibration data from in-service train. The vehicle-body and bogie acceleration responses are correlated with the two target variables by modeling train-bridge interaction (TBI) through least squares generative adversarial network (LSGAN). To realize supervised learning required in the present task, the conventional LSGAN is modified by implementing new loss function and linear activation function. The proposed approach can offer pointwise and accurate estimates of track dynamic irregularity and bridge acceleration, allowing frequent inspection of high-speed railway (HSR) bridges in an economical way. Thanks to its applicability in scenarios of high noise level and critical resonance condition, the proposed approach has a promising prospect in engineering applications.

• 한국구조물진단유지관리공학회 논문집
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• 제20권1호
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• pp.33-40
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• 2016

본 연구에서는 비용예측모델과 성능예측모델을 이용하여 네트워크 레벨에서 향후 교량과 터널 유지관리 비용과 성능을 예측할 수 있는 방법론은 개발하였다. 현재 국내의 시설물 유지관리 관련 연구는 대부분 단일 시설물에 집중되어 있어 도로망차원의 네트워크 레벨 분석에는 적용하기 어렵다. 따라서 시설물군 단위로 유지관리 계획을 수립해야하는 실무주체에게 유의한 정보를 제공하지 못하고 있는 실정이다. 본 연구의 예측모델은 시설물의 성능에 현재 시특법에 의해 평가하고 있는 상태외 사용성과 기능성을 포함하였으며, 기본 분석과 확장 분석을 통해 각 시설물의 조치 시기와 연간 예산을 추정할 수 있다. 또한 사례 분석을 통해 기술적 타당성을 검증하였다. 본 연구의 방법론이 활성화된다면 다수의 시설물의 비용대비 미래 성능을 파악할 수 있으며, 효과적인 중장기 예산 수립을 할 수 있을 것으로 판단된다.

• 정신신체의학
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• 제31권2호
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• pp.118-124
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• 2023

연구목적 우울장애와 불안장애는 흔히 공존하며 임상전단계에서도 흔히 공존한다. 본 연구는 일반인구 집단에서 우울장애와 불안장애가 공존시의 복합 네트워크를 구성하여 중심 증상과 중개 증상을 밝히고자 했다. 방 법 2022년 아산시 청년 정신건강실태조사 데이터를 활용하여 진행하였다. 일반 인구집단 810명의 성인을 대상으로 PHQ-9과 GAD-7을 이용하여 각각 우울과 불안증상의 정도를 측정하였고, 각 증상에 대해 Isingfit model을 기반으로 네트워크 구조를 도출하였다. 주요 증상 및 중개 증상을 찾기 위해 네트워크 지표 중 강도 중심성과 bridge expected influence를 활용하였다. 결 과 우울한 기분, 안절부절 못함과 초조함이 네트워크에서 가장 높은 강도중심성을 보였으며, 불안증상과 우울증상 간의 높은 중개 역할을 하는 증상은 안절부절 못함과 과민성이었다. 결 론 일반 인구집단에서 우울증상과 불안증상이 공존할 때의 중심증 상과 중개증상을 규명하였고 치료적 중재의 목표가 되면 두 질환의 동반이환율을 감소시키는데 기여할 수 있을 것으로 기대된다.

• Smart Structures and Systems
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• 제12권6호
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• pp.679-694
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• 2013

In this paper the application of the Interpolation Damage Detection Method to the numerical model of a suspension bridge instrumented with a network of Micro-Electro-Mechanical System sensors is presented. The method, which, in its present formulation, belongs to Level II damage identification method, can identify the presence and the location of damage from responses recorded on the structure before and after a seismic damaging event. The application of the method does not require knowledge of the modal properties of the structure nor a numerical model of it. Emphasis is placed herein on the influence of recorded signals noise on the reliability of the results given by the Interpolation Damage Detection Method. The response of a suspension bridge to seismic excitation is computed from a numerical model and artificially corrupted with random noise characteristic of two families of Micro-Electro-Mechanical System accelerometers. The reliability of the results is checked for different damage scenarios.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권8호
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• pp.3025-3047
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• 2021

This paper presents the latest Ethernet standardization of in-vehicle network and the future trends of automotive Ethernet technology. The proposed system provides design and optimization algorithms for automotive networking technology related to AVB (Audio Video Bridge) technology. We present a design of in-vehicle network system as well as the optimization of AVB for automotive. A proposal of Reduced Latency of Machine to Machine (RLMM) plays an outstanding role in reducing the latency among devices. RLMM's approach to real-world experimental cases indicates a reduction in latency of around 41.2%. The setup optimized for the automotive network environment is expected to significantly reduce the time in the development and design process. The results obtained in the study of image transmission latency are trustworthy because average values were collected over a long period of time. It is necessary to analyze a latency between multimedia devices within limited time which will be of considerable benefit to the industry. Furthermore, the proposed reliable camera and video streaming through optimized AVB device settings would provide a high level of support in the real-time comprehension and analysis of images with AI (Artificial Intelligence) algorithms in autonomous driving.