• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.238-238
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• 2023

소형선박인 어선·낚시어선의 전복 사고로 인한 인명 사고가 지속적으로 발생 되어지고 있다. 소형선박인 어선·낚시어선의 운항 시 선박의 운항자가 선박의 실시간 복원성 상태 인지 없이 어업 또는 낚시 활동하는 동안 해양 환경 상태 또는 적화 상태 변화와 추가적인 외력에 의해서 선박의 전복 사고가 발생 되어진다. 본 연구에서는 소형선박 어선·낚시어선의 실시간 복원성 감시를 위한 안전키트의 실험적 검증을 실시했다. 안전키트의 자이로센서를 활용하여 실시간 횡요각 데이터 측정 및 주파수 분석하여 횡요주기를 도출하고 횡메타센터(GM)을 도출한다. 또한, 실사간 도출된 GM에 따라 국제해사기구(IMO, International Maritime Organization) 비손상 복원성 평가 기준 값을 추정한다. 실험적 검증을 통하여 개발된 소형선박 어선·낚시어선용 안전키트의 정확도 확인 및 개선점을 발견하였으며, 향후 연구 계획에 대해서 제시했다.

• Bulletin of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.31-43
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• 1993

본 연구에서는 힁부재가 없는 AFRAMAX급 신구조 방식의 유조선을 개발하고자 하였다. 설계의 기본 개념은 1) 이중선체구조를 채용하여 해난사고 발생시 기름유출 방지를 피하고, 2) 힁부재가 없는 극히 단순한 선체구조를 채용하여 용접 로봇등을 활용한 자동건조 비율을 높임으로써 건조 생산성을 향상시키는데 주안점을 두고 있다. 설계 결과 얻어진 선체구조는 기존의 유조선 구 조와 매우 상이하다. 초기구조설계단계에서 구조 부재의 치수는 기존의 선급설계 지침을 활용 하여 결정하였으나, 기존의 유조선 구조와 비교하여 구조배치가 크게 바뀌어 졌기 때문에 기존의 선급설계지침을 만족했다고 해서 구성부재와 국부구조뿐만 아니라 구조 전체적으로도 충분한 구조안전성을 가지고 있는지는 확실치 않다. 따라서 직접구조해석에 의한 구조안전성 평가가 필수적으로 요구되며, 이를 위해 저자들은 선체구조의 최종 종강도(ultimate longitudinal strength), 최종 힁강도(ultimate transverse strength) 및 최종 국부강도(ultimate local strength )를 기준으로한 구조안전성 평가를 수행하였다. 본 논문에서는 이들 중에서 국부 구조부재에 대한 안전성평가 문제만을 다루었다. 결론적으로, 본 연구에서 개발한 선체구조는 건전상태(intact condition)하에서 뿐만 아니라 손상상태하에서도 구조부재는 좌굴 또는 붕괴하지 않고 전반적 으로 충분한 구조안전성을 가지고 있다는 결론을 내릴 수 있었다.

• Therapeutic Science for Rehabilitation
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• v.1 no.1
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• pp.71-79
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• 2012

Objective : To investigate the correlation between relationship ability and ADL performance ability of patients with TBI. Methods : This study was carried out from March 2012 to April 2012 with 20 patients with TBI. Relationship ability assessed using Relationship Change Scale(RCS), ADL performance ability assessed using Functional Independence Measure(FIM). Results : The RCS showed a high level of correlation with marital status and duration of illness. The RCS showed a high level of correlation with the FIM total score and the FIM cognition area. However the RCS did not show a correlation with the FIM motor area. Conclusions : Functional disability of social cognition is a factor that disturbs rehabilitation after TBI and it has a negative influence on the relationship in ADL. If accurate evaluation and treatment on relationship ability after TBI are carried out side by side from the initial stages of onset, we could expect more patients to improve their social cognition and ADL performance ability.

• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.45-53
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• 2009

More than 40% of railway bridges on the conventional lines in Korea consist of track-on-steel plate girder (TOSPG) bridges. This type of bridge is typically designed without considering seismic loadings, as most of them were built before 1970. The seismic performance of this particular type of bridge could be upgraded through various seismic retrofit schemes, and seismic risk assessment could play a key role in decision-making on the level of the seismic retrofit. This study performed a seismic risk assessment of TOSPG bridges in Korea. The seismic damage of several crucial components of TOSPG bridges--fixed bearings, free bearings, and piers--were probabilistically estimated, and their seismic fragility curves were developed. The probability that the components would exceed their predefined limit states was also calculated by combining the fragility curves and the seismic hazard function. The analysis showed that the piers of TOSPG bridges, which are made of plain concrete without rebars, have relatively low risk against seismic loadings in Korea. This is because the mass of the superstructures of TOSPG bridges is relatively small, and hence, the seismic loading being transferred to the piers is minimal. The line-type bearings typically used for TOSPG bridges, however, are exposed to a degree of seismic risk. Among the bearings, the probability of the free-end bearings and the fixed-end bearings exceeding the slight damage state in 50 years was found to be 12.78% and 4.23%, respectively. The gap between these probability values lessened towards more serious damage states. This study could effectively provide an engineering background for decision-making activities on the seismic retrofit of railway bridges.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.229-237
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• 2007

In this study, an artificial neural network (ANN)-based damage detection algorithm using acceleration signals is developed for real-time alarming locations of damage in beam-type structures. A new ANN-algorithm using output-only acceleration responses is designed tot damage detection in real time. The cross-covariance of two acceleration-signals measured at two different locations is selected as the feature representing the structural condition. Neural networks are trained lot potential loading Patterns and damage scenarios of the target structure for which its actual loadings are unknown. The feasibility and practicality of the proposed method are evaluated from laboratory-model tests on free-free beams for which accelerations were measured before and after several damage cases.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.299-307
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• 2007

In this study, a new concept for simulating a physical damage of tunnel shotcrete lining due to a long-term chemical deterioration has been proposed. It is known that the damage takes place mainly by internal cracks, reduction of stiffness and strength, which results mainly from volume expansion of the lining and corrosion of cement materials, respectively. This damage mechanism of shotcrete lining appears similar in most kinds of chemical reactions in tunnels. Therefore, the mechanical deterioration mechanism induced by a series of chemical reactions was generalized in this study and mathematically formulated in the framework of thermodynamics. The numerical model was implemented to a 3D finite element code, which can be used to simulate behaviour of tunnel structures undergoing external loads as well as chemical deterioration in time. A number of illustrative examples were given to show a feasibility of the model in tunnel designs.

• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.613-625
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• 2002

This paper aimed to investigate the damage process of steel parts experiencing failure under strong repeated loading. Likewise, a damage index using various factors related to the damage was proposed. An analysis method for evaluating the damage state was also developed. The damage assessment method focused on the local strain history at the cross-section of the heaviest concentration of deformation. Cantilever-type steel parts were analyzed under uniaxial load combined with a constant axial load, considering horizontal displacement history, Loading patterns and steel types were considered as the main parameters in analyzing the models. The effects of the parameters on the failure modes, deformation capacity, and damage process as seen from the analysis results were also discussed. Each failure process was compared as steel types. In addition, the failure of steel parts under strong repeated loading was determined according to loading. Results revealed that the state of the failure is closely related to the local plastic strain.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.383-386
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• 2009

본 연구는 HAZUS에서 제시하고 있는 비보강 조적조 건축물의 구조적 손상상태에 대한 지진취약도함수와 관련하여 층간변위율 및 스펙트럼 변위 등의 매개변수를 평가하고 또한 국내 상황에 적합한 기존 비보강 조적조 건축물의 지진취약도곡선의 도출을 목적으로 하였다. 국내 상황을 고려한 지진피해를 추정하기 위하여 먼저 기존 비보강 조적조 건축물의 현황파악 및 지진취약도함수 산출방법을 분석하였다. 일반적으로 HAZUS에서 제시하고 있는 지진취약도함수는 역량스펙트럼을 변환시킨 가속도-변위응답 스펙트럼법을 기본적으로 사용하는 상황으로 국내 기존 비보강 조적조 건축물에 대한 지진취약도함수 개발을 위하여 Midas GEN Ver.741 구조해석프로그램을 사용하여 실제 23개동의 비보강 조적조 건축물을 대상으로 역량스펙트럼 해석을 수행하였다. 연구결과를 통하여 지진취약도함수의 주요 매개변수인 손상상태별 층간변위율 및 스펙트럼 변위를 제시하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.119-130
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• 2009

Seismic fragility curves of a structure represent the probability of exceeding the prescribed structural damage state for a given various levels of ground motion intensity such as peak ground acceleration (PGA), spectral acceleration ($S_a$) and spectral displacement ($S_d$). So those are very essential to evaluate the structural seismic performance and seismic risk. The purpose of this paper is to develop seismic fragility curves for PSC box girder bridges. In order to construct numerical fragility curve of bridge structure using nonlinear time history analysis, a set of ground motions corresponding to design spectrum are artificially generated. Assuming a lognormal distribution, the fragility curve is estimated by using the methodology proposed by Shinozuka et al. PGA is simple and generally used parameter in fragility curve as ground motion intensity. However, the PGA has not good relationship with the inelastic structural behavior. So, $S_a$ and $S_d$ with more direct relationship for structural damage are used in fragility analysis as more useful intensity measures instead of PGA. The numerical fragility curves based on nonlinear time history analysis are compared with those obtained from simple method suggested in HAZUS program.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.319-328
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• 2020

The purpose of this study is to assess the relationships of alcohol consumption patterns to mental distress and self-rated health. Data of 19,856 adult drinkers over 19 years of age and older from the Korea National Health and Nutrition Examination Survey were evaluated by multivariate logistic regression analysis. Risks of experiencing perceived high stress, depressive symptoms and suicidal thoughts were higher in alcohol use disorder group in male, whereas the risks were higher in both alcohol use disorder and hazardous drinking groups in female, reflecting higher susceptibility to mental distress. In both male and female, former drinkers presented poor self-rated health compared with low-risk drinkers, although no difference was found in the prevalence of mental distress. Specialized mental health management measures for female drinkers are required, and former drinkers are suggested to be assessed separately from never or low-risk drinkers for their physical and mental health status.