• Structural Monitoring and Maintenance
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• v.6 no.1
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• pp.67-84
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• 2019

Digital Image Correlation technique (DIC) is a non-contact optical method for rapid structural health monitoring of critical infrastructure. An innovative approach to DIC is presented using QR (Quick Response) code based random speckle pattern. Reinforced Cement Concrete (RCC) beams of size $1800mm{\times}150mm{\times}200mm$ are tested in flexure. DIC is used to extract Moment (M) - Curvature (${\kappa}$) relationships using random speckle patterns and QR code based random speckle patterns. The QR code based random speckle pattern is evaluated for 2D DIC measurements and the QR code speckle pattern performs satisfactorily in comparison with random speckle pattern when considered in the context of serving a dual purpose. Characteristics of QR code based random speckle pattern are quantified and its applicability to DIC is explored. The ultimate moment-curvature values computed from the QR code based random speckled pattern are found to be in good agreement with conventional measurements. QR code encrypts the structural information which enables integration with building information modelling (BIM).

• Korean Journal of Human Ecology
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• v.22 no.5
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• pp.477-490
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• 2013

This study explores critical and success factor of benefits and risks for predicting the acceptance of QR code virtual fashion stores. As an exploratory approach, this study conducted focus group interviews(FGI) with 21 panels who had experience with selected QR virtual stores (e.g., Home plus, 11th Street, Pin & Fit). Content analysis was used to generate 184 excerpts and classify into benefits and risks related to QR code virtual stores. With respect to benefits, content analysis identified four factors: Affective appeal, perceived usefulness, ubiquity, and brand promotion. Also, contents regarding perceived risks were classified into four factors: Complexity, lack of information, lack of technology infrastructure, and perceived cost. A managerial implication was discussed for predicting consumer technology acceptance of a QR code virtual store in the fashion retailing market.

• International Journal of High-Rise Buildings
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• v.9 no.4
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• pp.369-376
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• 2020

Given the importance of quickly recovering livelihoods and economic activity after an earthquake, the seismic performance of the pile foundation is becoming more critical than before. In order to promote seismic retrofit of the pile foundations, it is necessary to develop a method for evaluating the seismic performance of the pile foundation based on the experimental data. In this paper, we focus on the building that was suffered severe damage to the pile foundation, conduct simulation analyses of the building, and report the results of evaluating the dynamic characteristics when piles are damaged using a system identification method. As a result, an analysis model that can accurately simulate the behavior of the damaged building during an earthquake was constructed, and it was shown that the system identification method could extract dynamic characteristics that may damage piles.

• East Asian Economic Review
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• v.24 no.4
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• pp.349-388
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• 2020

The US-China trade war forced a reluctant semiconductor industry into someone else's fight, a very different position from its leading role in the 1980s trade conflict with Japan. This paper describes how the political economy of the global semiconductor industry has evolved since the 1980s. That includes both a shift in the business model behind how semiconductors go from conception to a finished product as well as the geographic reorientation toward Asia of demand and manufactured supply. It uses that lens to explain how, during the modern conflict with China, US policymakers turned to a legally complex set of export restrictions targeting the semiconductor supply chain in the attempt to safeguard critical infrastructure in the telecommunications sector. The potentially far-reaching tactics included weaponization of exports by relatively small but highly specialized American software service and equipment providers in order to constrain Huawei, a Fortune Global 500 company. It describes potential costs of such policies, some of their unintended consequences, and whether policymakers might push them further in the attempt to constrain other Chinese firms.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.167-168
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• 2023

에너지분야 국가핵심기반시설에서 산업재해 및 업무중단 사고예방을 위해 재해경감활동관리체계(BCMS)에서 일일위험지수 재난안전관리 프로그램을 자체개발 운용하여 정부의 중대재해 감축 로드맵의 핵심적인 4대 전략 중 하나인 사업장에서 유해위험요인에 대한 자기규율적인 예방관리체계의 확립한 사례를 제시하였다. 이에 대한 신뢰성 검증을 위해 중대산업재해 감축효과에 영향을 미친 사업장의 BCMS, 일일위험지수 및 중대재해처벌법 간의 관계성을 연구한 결과, 제도 간 개념의 관련성이 높으며, 상호 보완적이고 영향을 미치는 것으로 확인되었다. 따라서 동종 사업장에서 재해경감활동관리체제의 일일위험지수를 활용한다면 중대재해예방관리에 도움이 될 것으로 기대된다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.251-252
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• 2022

국가핵심기반은 국가 운영을 위하여 사업의 중단 없이 연속적으로 운영될 필요가 있다. 본 연구에서는 에너지관련 기관을 대상으로 재해를 예방하기 위하여 위험작업의 위험도 평가와 위험수준에 맞는 적절한 관리순찰 강화방안을 중심으로 개발된 일일안전지수 제도를 소개하고 그 효과성에 대하여 검토하였다. 그 결과 일일안전지수는 중대재해를 효과적으로 감소시키는 것으로 분석되었다. 일일안전지수제도는 다른 국가핵심기반에서도 적합하게 응용 적용하여 재해를 예방할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1630-1642
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• 2016

Inter-domain routing is the most critical function of the Internet. The routing system is a logical network relying on the physical infrastructure with geographical characteristics. Nature disasters or disruptive accidents such as earthquakes, cable cuts and power outages could cause regional failures which fail down geographically co-located network nodes and links, therefore, affect the resilience of inter-domain routing system. This paper presents a model for regional failures in inter-domain routing system called REFER for the first time. Based on REFER, the resilience of the inter-domain routing system could be evaluated on a finer level of the Internet, considering different routing policies of intra-domain and inter-domain routing systems. Under this model, we perform simulations on an empirical topology of the Internet with geographical characteristics to simulate a regional failure locating at a city with important IXP (Internet eXchange Point). Results indicate that the Internet is robust under a city-level regional failure. The reachability is almost the same after the failure, and the reroutings occur at the edge of the Internet, hardly affecting the core of inter-domain routing system.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.126-127
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• 2013

In industry, Supervisory Control and Data Acquisition (SCADA) system plays critical role to ensure production is monitored and controlled rigorously and in timely manner. Having a cost saving yet still effective SCADA system would be much desired by Industry. SCADA itself is a field with constant development and research like how this paper investigates on creating an extremely low cost device, which can be adapted to many different SCADA applications through some very basic programming when combined with relevant peripherals. Much of the process in some expensive SCADA application based on smartphone application is due to specialized communication infrastructure. This paper addresses the needs by developing low cost and integrated wireless SCADA system. The system features capability on accessing the performance of remotely situated device parameter, such as temperature, control analog or digital input output on real time basis. We use existing mobile network capability through Bluetooth communication channel.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.305-310
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• 2013

In general, it is difficult to measure dynamic responses of a bridge with stepwise increasing speed of a train during commercial service on a high speed railroad. However, before opening the 2nd stage of the Gyeongbu high speed railroad, there was an opportunity for field tests and measurements of the bridge with stepwise increasing speed(from 170km/ h to 315km/h). The measured responses were compared with the results of a developed bridge/train interaction analysis. Although good agreement was found throughout almost the entire range of speeds, relatively large differences were found in the vicinity of the critical speed at which resonance behavior of the bridge occurs. To investigate the cause of this, reanalyses are performed with re-estimated damping ratios from field tests.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.81-92
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• 2018

Recently, the use of natural gas has steadily increased due to its economical advantage and increased demand of clean energy uses. Accordingly, construction of LNG storage tanks is also increased. Secure of the stability of LNG tanks storage requires high technology as natural gas is stored in a liquid state for efficiency of storage. When a cryogenic LNG fluid leaks on ground due to a defect in LNG tank, damage is expected to be significant. Many researchers evaluated the critical and negative effects of LNG leakage, but there is limited research on the effect of cryogenic fluid leakage on the ground supporting LNG tanks. Therefore, in this study, the freezing expansion of the ground during cryogenic LNG fluid leakage was evaluated considering various outflow situations and ground conditions. The LNG leakage scenarios were simulated based on numerical analyses results varying the surcharge load, temperature boundary conditions, and soil types including freeze-sensitive soil. Consequently, short and long term ground temperature variations after LNG leakage were evaluated and the resulting ground behavior including vertical displacement behavior and porosity were analyzed.