• Earthquakes and Structures
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• 제21권6호
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• pp.627-639
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• 2021

Fragility curves are being more significant as a useful tool for evaluating the relationship between the earthquake intensity measure and the effects of the engineering demand parameter on the buildings. In this paper, the effect of different site conditions on the vulnerability of the structures was examined through the fragility curves taking into account different strength capacities of the precast columns. Thus, typical existing single-story precast RC industrial buildings which were built in Turkey after the year 2000 were examined. The fragility curves for the three typical existing industrial structures were derived from an analytical approach by performing non-linear dynamic analyses considering three different soil conditions. The Park and Ang damage index was used in order to determine the damage level of the members. The spectral acceleration (Sa) was used as the ground motion parameter in the fragility curves. The results indicate that the fragility curves were derived for the structures vary depending on the site conditions. The damage probability of exceedance values increased from stiff site to soft site for any Sa value. This difference increases in long period in examined buildings. In addition, earthquake demand values were calculated by considering the buildings and site conditions, and the effect of the site class on the building damage was evaluated by considering the Mean Damage Ratio parameter (MDR). Achieving fragility curves and MDR curves as a function of spectral acceleration enables a quick and practical risk assessment in existing buildings.

• Geomechanics and Engineering
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• 제37권6호
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• pp.565-576
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• 2024

In this study, the earthquake risk assessment of single-story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub-classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub-class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub-classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

• Coupled systems mechanics
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• 제9권4호
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• pp.359-379
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• 2020

Due to susceptibility of bridges in the past earthquakes, vulnerability assessment and strengthening of bridges has gained a particular significance. The objective of the present study is to employ an analytical method for the development of fragility curves, as well as to investigate the effect of strengthening on the RC box-girder bridges. Since fragility curves are used for pre-and post-earthquake planning, this paper has attempted to adopt the most reliable modeling assumptions in order to increase the reliability. Furthermore, to acknowledge the interaction of soil, abutment and pile, the effect of different strengthening methods, such as using steel jacketing and FRP layers, the effect of increase in the bridge pier diameter, and the effect of vertical component of earthquake on the vulnerability of bridges in this study, a three-span RC box-girder bridge was modeled in 9 different cases. Nonlinear dynamic analyses were carried out on the studied bridges subjected to 100 ground motion records via OpenSEES platform. Therefore, the fragility curves were plotted and compared in the four damage states. The results revealed that once the interaction of soil and abutment and the vertical component of the earthquake are accounted for in the calculations, the median fragility is reduced, implying that the bridge becomes more vulnerable. It was also confirmed that steel jackets and FRP layers are suitable methods for pier strengthening which reduces the vulnerability of the bridge.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제27권3호
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• pp.188-195
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• 2016

Objectives: The aim of this study was to investigate the relationship between internet addiction, smartphone addiction, and psychosocial factors. This study was designed to examine the vulnerability factors for internet and smartphone addiction. Methods: The participants were 1041 children and adolescents in a small and medium-sized cities. All of the participants were evaluated in terms of their demographic characteristics and present use of the internet and smartphone, as well as using internet and smartphone addiction and other psychological scales. Statistical analyses were performed to compare the psychosocial factors between the high risk, potential risk, and general user groups of internet and smartphone addiction. Results: The participants were classified into three groups, the high risk (N=33), potential risk (N=203), and general user (N=805) groups with regard to their internet and smartphone addiction level. There were statistical significantly differences between the groups in terms of the economic status of the family, academic performance, parents, use of internet and smartphone, loneliness, family cohesion, family adaptability, perceived social support, and peer relationship. Conclusion: These results suggest that the internet and smartphone addiction of children and adolescents is related to various psychosocial vulnerability factors.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3301-3307
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• 2016

Background: Cancer is a leading cause of death in Korea. To prevent cancer, it is essential to facilitate and promote appropriate cancer screening behavior in the adult population. The aim of this study was to examine health beliefs related to cancer screening intentions using the Health Belief Model (HBM). Materials and Methods: The research participants comprised 275 male health and safety managers at commercial companies in Korea. The self-administered survey explored demographic characteristics, cancer-related factors, beliefs about cancer/cancer screening (BCCS) (vulnerability to cancer, severity of cancer, benefits of screening, and barriers to screening), and cancer screening intention. Multivariate logistic regression analyses were used to identify factors associated with an intention to be screened for cancer. Results: Perceived health status and need for cancer prevention education were major factors associated with BCCS. Poorer health status was associated with greater perceived vulnerability, a perception of fewer benefits, and more barriers (p<0.05). A perceived greater need for cancer prevention education was associated with a higher perceived severity of cancer and more perceived barriers to screening (p<0.05). Marital status, cancer screening experience, and perceived vulnerability to cancer were significant influences on the cancer screening intention (p<0.05). Participants who had undergone cancer screening in the past 2 years were more likely to intend to be screened for cancer than were those who had not been screened; this was true across all degrees of intention and all types of cancer (p<0.01). Hesitant people considered themselves less vulnerable to gastric, lung, and liver cancer than did the poeple who intended to undergo cancer screening (p<0.05). Conclusions: Based on our findings, we recommend that workplace cancer prevention programs attempt to increase awareness about vulnerability to cancer among workers who hesitate to undergo cancer screening.

• 사회복지연구
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• 제45권2호
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• pp.233-261
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• 2014

본 연구에서는 국내 성인의 자아존중감과 우울의 인과관계를 살펴보는데 목적을 두고, 한국복지패널 1~4차 데이터를 활용하여 인과관계를 설명할 수 있는 인지취약모델과 상처모델을 검증하였다. 또한 우울과 자아존중감의 변화궤적에 영향을 미치는 인구사회학적 변인을 파악함으로써 우울과 자아존중감 손상에 취약한 인구집단을 밝히고자 하였다. 분석결과 우울의 초기값이 자아존중감 변화율에 미치는 영향과 자아존중감 초기값이 우울 수준 변화율에 미치는 영향이 모두 유의하게 나타나 외국 연구와는 달리 국내 성인집단에서는 인지취약모델과 상처모델이 모두 지지되는 것으로 밝혀졌다. 또한 이 상호관계는 인구사회학적 요인을 통제한 상태에서도 지지되었으며, 우울의 변화궤적과 자아존중감의 변화궤적 모두에 유의한 영향을 미치는 요인으로는 교육수준, 빈곤여부, 만성질환 여부 및 사회적 관계 만족도로 나타났다. 본 연구는 아직까지 연구되지 않은 성인기 집단의 우울과 자아존중감 관계의 매커니즘을 밝혔다는데 의의가 있으며, 논의를 통해 우울 예방 및 치료에 대한 실천적 함의를 제안하였다.

• 한국지진공학회논문집
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• 제27권5호
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• pp.221-230
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• 2023

This study proposes a methodology for assessing seismic liquefaction hazard by implementing high-resolution three-dimensional (3D) ground models with high-density/high-precision site investigation data acquired in an area of interest, which would be linked to geotechnical numerical analysis tools. It is possible to estimate the vulnerability of earthquake-induced geotechnical phenomena (ground motion amplification, liquefaction, landslide, etc.) and their triggering complex disasters across an area for urban development with several stages of high-density datasets. In this study, the spatial-ground models for city development were built with a 3D high-precision grid of 5 m × 5 m × 1 m by applying geostatistic methods. Finally, after comparing each prediction error, the geotechnical model from the Gaussian sequential simulation is selected to assess earthquake-induced geotechnical hazards. In particular, with seven independent input earthquake motions, liquefaction analysis with finite element analyses and hazard mappings with LPI and LSN are performed reliably based on the spatial geotechnical models in the study area. Furthermore, various phenomena and parameters, including settlement in the city planning area, are assessed in terms of geotechnical vulnerability also based on the high-resolution spatial-ground modeling. This case study on the high-precision 3D ground model-based zonations in the area of interest verifies the usefulness in assessing spatially earthquake-induced hazards and geotechnical vulnerability and their decision-making support.

• 한국융합학회논문지
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• 제11권10호
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• pp.9-18
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• 2020

현 연구는 개별 건물에 대한 지진취약도 예측 및 특정 관심 지역 내 전체 건물의 안전 상태를 예측하는 방법의 제시에 그 목적이 있다. 현 연구의 범위는 지진피해 저감 연구 중, 예방 활동에 속하는 시뮬레이터 모델개발, 모델 유효성 검증을 포함한다. 연구의 대상은 지역 건물 시스템이다. 선행연구 조사 결과, 국내의 지진 예측 모델링 및 그 결과를 GIS를 활용해 적용한 사례의 성과는 아직은 미비한 것으로 판단되었으며, 이를 다소간이나마 개선하기 위한 방편의 일환으로 현 연구가 진행되었다. 국내·외 총 348개의 데이터를 사용해 통계 분석이 실시되었다. 일련의 통계 분석 결과, 최적화 척도법에 의한 모델이 개발되었고, 모델의 예측 정확도는 87%로 산정되었다. 통계 분석을 통해 개발된 모델식을 지역 건물 시스템의 지진취약도 예측에 적용하기 위해, 공간 분석 기법이 활용되었다. 서울시 구도심과 신도심의 특성을 대표하는 강남구와 종로구 그리고 종로구와 지반 조건이 유사한 은평구를 대상 지역으로 선정하였고, 분석 결과 건물을 대상으로 강남구가 종로구와 은평구에 비해 위험한 것으로 예측되었다.

• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.701-705
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• 2011

RFID is a widely adopted in the field of identification technology these days. Radio Frequency IDentification (RFID) has wide applications in many areas including manufacturing, healthcare, and transportation. Because limited resource RFID tags are used, various risks could threaten their abilities to provide essential services to users. A number of RFID protocols have done by researcher in order to protect against some malicious attacks and threat. Existing RFID protocols are able to resolve a number of security and privacy issues, but still unable to overcome other security & privacy related issues. In this paper, we analyses security schemes and vulnerability in RFID application. Considering this RFID security issues, we survey the security threats and open problems related to issues by means of information security and privacy. Neither a symmetric nor an asymmetric cryptographic deployment is necessarily used with light weighted algorithm in the future.

• 한국지진공학회논문집
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• 제22권3호
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• pp.149-160
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• 2018

This study experimentally and analytically examines the seismic vulnerability of steel rack storage frames subjected to Korea earthquakes (2016 Gyeongju earthquake and 2017 Pohang earthquake). To achieve this aim, this study selects a three-story, one-bay steel rack frame with a typical configuration of rack frame in Korea. Firstly, the local behavior for frame components is examined by performing monotonic and/or cyclic load tests and the global response and dynamic characteristics of the subject rack frame are investigated by conducting a shaking table test. The analytical model of the rack frame is then created based on the experimental results and is used to perform nonlinear time history analyses with recorded Korea earthquakes. The seismic demand of the rack frame is considerably affected by the spectral acceleration response, instead of peak ground accelerations (peak floor accelerations). Moreover, the collapse fragility curve of the rack frame is developed using incremental dynamic analyses for the Gyeongju and Pohang earthquakes. Fragility results indicate that the ground motion characteristics of these earthquakes do not significantly affect the frame vulnerability at the collapse state.