• Structural Engineering and Mechanics
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• 제50권1호
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• pp.105-119
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• 2014

This study presents a steel container crane movement analysis and assessment based on structural health monitoring (SHM). The accelerometers are used to monitor the dynamic crane behavior and a 3-D finite element model (FEM) was designed to express the static displacement of the crane under the different load cases. The multi-input single-output nonlinear autoregressive neural network with external input (NNARX) model is used to identify the crane dynamic displacements. The FEM analysis and the identification model are used to investigate the safety and the vibration state of the crane in both time and frequency domains. Moreover, the SHM system is used based on the FEM analysis to assess the crane behavior. The analysis results indicate that: (1) the mean relative dynamic displacement can reveal the relative static movement of structures under environmental load; (2) the environmental load conditions clearly affect the crane deformations in different load cases; (3) the crane deformations are shown within the safe limits under different loads.

• 대한안전경영과학회지
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• 제14권3호
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• pp.11-19
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• 2012

Especially because of the distinctiveness that new experiments and research provoke coexistence of various risk factors, the researchers in university laboratory are being exposed to incidents that are difficult to predict. Due to the fact that the numbers of accidents that occur at the university laboratory are increasing, the necessity for laboratory safety management is on the rise. Most laboratory accidents are caused by the ability that can detect risk factors such as unsafe behavior or unsafe condition but is not working perfectly. In order to prevent researchers in advance from unsafe behavior or unsafe condition, effective safety education, systematic safety management, safe research environment, continuous safety check and proper measures after accident are the most important factors. In this study, survey was conducted in university laboratory to identify the factors that affect on safety management and to measure the safety management level. As a result, effective measures are proposed for the improvement of the safety management level.

• 대한의용생체공학회:의공학회지
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• 제41권1호
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• pp.1-7
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• 2020

Polyvinyl alcohol (PVA)/gelatin hydrogels were prepared by repeating freezing/thawing three times to evaluate the influence of PVA concentration on the strength and the cell growth behavior of the PVA/gelatin hydrogels. The swelling rate of the PVA/gelatin hydrogels decreased with raising the PVA content from 6 wt% to 12 wt% due to the formation of 3-D network inside the hydrogel. No appreciable degradation of the hydrogels was detected. As the PVA content increased from 6 wt% to 12 wt%, the strength of the PVA/gelatin hydrogels increased drastically from 6.4±0.9 kPa to 46.6±9.0 kPa. The PVA/gelatin hydrogels did not show any evidence of causing cell lysis or toxicity, implying that the hydrogels are clinically safe and effective. Although the strength increased with increasing the PVA content, the PVA/gelatin hydrogels containing 8 wt% exhibited the fastest cell growth, which is highly suitable for wound dressing requiring fast healing regeneration.

• 한국입자에어로졸학회지
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• 제10권4호
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• pp.177-182
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• 2014

In this study, nickel-coated aluminum (Ni/Al) powders were synthesized for the utilization of energetic applications. Oxide materials present at the surface of Al powders of $45{\mu}m$ in averaged size were removed by using sodium hydroxide(NaOH) solution which is used for controlling pH. Nickel material is coated into the surface of oxide-removed Al powders by electroless-plating process. The microstructure of fabricated Ni/Al powders shows that nickel layers with a few hundreds nm were very homogeneously formed onto the surface of Al powders. The oxidation behavior of Ni/Al exihibit somewhat faster oxidation rate than that of pure Al with surface oxidation. Also, the higher exothermic reaction was observed from the Ni/Al powders. From the result of this, nickel coating is very promising method to obtain highly reactive and safe Al powders for energetic applications.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.266-267
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• 2017

본 연구에서는 중첩된 두 비행물체에서 단분리 시 일어나는 주위 유동장 해석에 초점을 맞춰 해석을 수행하였다. 수치적인 해석을 위하여 정지된 비행체에서 분리되는 실린더 형태의 부스터를 중첩격자를 이용하여 모델링 하였으며 상용해석코드인 CFD-FASTRAN$^{TM}$을 사용하여 계산하였다. 실제 현상을 모사하기 위하여 경계조건 및 외력을 도출하였으며 각 비행조건에 따른 부스터 분리 시 주위 유동장 해석을 수행하였다. 단분리 시의 비행속도와 받음각 조건에 대한 해석결과를 이용하여 실제 분리 현상을 모사할 수 있는 수치적인 경계조건을 파악하고 안전한 단분리 예측에 본 연구결과를 활용하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.295-299
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• 2005

본 연구는 개선된 거리변환 알고리즘을 사용하여 로봇이 이동해야 할 경로를 생성하고, 퍼지 시스템을 사용하여 경로추적 행위기와 장애물 회피 행위기를 구현해서 로봇이 그 경로를 안전하고 효율적으로 추적하는 것을 목적으로 하였다. 개선된 거리변환 알고리즘을 이용하여 로봇의 유연한 주행을 가능하게 했으며, 또한 주행거리와 주행시간도 단축되는 것을 확인할 수 있었다. 경로생성 후 경로를 추적할 때는 퍼지 시스템을 이용한 경로추적 행위기와 장애물 회피 행위기를 선택적으로 사용해서 경로추적 중에 예상치 못한 장애물이 발견되었을 경우에도 장애물을 회피한 후에 계속해서 경로를 추적하는 것을 확인함으로써 경로생성 후의 외부환경변화에도 강인함을 볼 수 있었다.

• 한국항만학회지
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• 제14권4호
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• pp.429-439
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• 2000

The primary purpose of dredging work is to maintain navigational readiness and to increase environmental amenity. Therefore the dredging project, which is composed of excavating, removing, transporting and storing or dumping dredged material, must be carefully managed to insure that dredging works are completed in a cost-effective and environmentally safe method. The most important point in dumping operations is evaluating and decreasing the impacts of dumping works at the dumping area. One of the most effective method for this purpose is using the schematic process composed of the sophisticate plan, precise work and predicting/reducing the impacts based on an numerical model being closely linked with field observation. In this study, a numerical model is used to predict the spatial transport and fate of the effluent discharged from the confined dumping facility(CDF) located at a coastal area. To achive this purpose, numerical models were used for reappearing the tidal current of concerned area. These models were then applied to Mokpo harbpr where capital dredging and maintenance dredging are being conducted simultaneously and the CDF is under construction. In series of model case study, we found that the effluent discharged from CDF was governed by the receiving water condition and outfall geometry, so that limit of near-field was 14∼500 meter down stream and 4∼150 meter in transverse direction. dilution ranged from 1.1 to 8.2 on the cases. Long-term diffusion characteristics was governed by the dilution rate during near-field behavior, ambient conditions and CDF operation modes.

• 한국안전학회지
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• 제34권6호
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• pp.58-64
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• 2019

Over the past decades there has been a growing body of researches that examines the psychological traits related to safety outcomes. After briefly reviewing the relationships between psychological dispositions and safety outcomes, we empirically examine the relationships with 2 samples of 1,102 participants. Fifteen psychological dispositions (big 5 personality, locus of control, cognitive failure, affection from job and relations, 4 achievement goal orientations, self-efficacy, fatigue, and depression) and four psychological outcomes (safe behavior, unsafe behavior, accidents, and injuries) are examined. After covariance structure modeling variances of safety outcomes are well explained by simple 4 dispositions of consciousness, mastery-approach goal orientation, self-efficacy, and depression. We name them 'core safety disposition', and name four psychological outcomes 'safety consciousness', and the relationships between those latent variables are stronger than between measurement variables. We propose core safety disposition as a cause of safety consciousness, and discuss implications for research and practices.

• 한국추진공학회지
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• 제22권4호
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• pp.91-98
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• 2018

본 연구에서는 중첩된 두 비행물체에서 단분리 시 일어나는 주위 유동장 분석에 초점을 맞춰 해석을 수행하였다. 수치 해석을 위하여 정지된 비행체에서 분리되는 실린더 형태의 부스터를 중첩격자를 이용하여 모델링 하였으며 상용해석코드인 $CFD-FASTRAN^{TM}$을 사용하여 계산하였다. 실제 현상을 모사하기 위해서는 부스터에 대한 스프링 반발력, 중력, 상대 속도 등의 고려가 필수적인 요소였다. 연구결과, 부스터의 분리 시간은 비행 마하수와 받음각이 증가함에 따라 감소하는 것을 확인할 수 있었으며, 현재까지의 결과를 종합하여 볼 때 본 연구에서 수행한 모델링과 경계조건 등의 구성이 비행시험의 안전한 부스터 분리와 이후 시퀀스를 예측하는데 많은 도움을 줄 것으로 판단된다.

• 대한조선학회논문집
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• 제53권2호
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• pp.162-169
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• 2016

A new concept of membrane type LNG CCS was proposed. Also, its static behavior was numerically analyzed considering the interaction between primary and secondary barrier together with securing device. Hull deflection was taken into account as an external load, together with temperature distribution across the barriers. The suggested numerical model considers both sliding and contact between the two mating surfaces of both the primary and secondary barrier, and anisotropic material behavior of plywood, R-PUF was also taken into account. Furthermore, detailed local strength was evaluated for the securing device, which is arranged between two barriers to hold the primary barrier. It was confirmed through the numerical analysis that the new concept of membrane type CCS was structurally safe under static loading condition and securing concept was structurally reliable.