• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.68-77
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• 2020

The shipbuilding and offshore industry is a large and complex assembly industry, which causes many safety accidents. The major accidents in the shipbuilding and offshore industry workplaces are stenosis, falling objects, dust, fire, explosions, and gas poisoning. The accident by worker in this industry mainly has three factors: frequent movement, narrow work space, and increased use of subcontractors. To control these factors, it is necessary to monitor the worker's location and work status. In this paper, a worker location monitoring system using inaudible sound wave was designd that can be used in environments with many metal barriers. The process included deriving stakeholder requirements, transforming to system requirements, designing system architecture, and developing prototype. The prototype was validated by third-party testing agency. As a result, it satisfied the designed performance and verified its feasibility.

• Journal of Power Electronics
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• v.14 no.5
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• pp.908-917
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• 2014

For the purpose of designing an intrinsic safety Flyback converter with minimal output voltage ripple based on a specified output current, this paper first classified the energy transmission modes of the system into three sorts, namely, the Complete Inductor Supply Mode-CCM (CISM-CCM), the Incomplete Inductor Supply Mode-CCM (IISM-CCM) and the Incomplete Inductor Supply Mode-DCM (IISM-DCM). Then, the critical secondary self-inductance assorting the three modes are deduced and expressions of the output voltage ripples (OVR) are presented. For a Flyback converter with constant loads and switching frequency, it is shown that the output voltage ripple in the CISM-CCM is the smallest and that it has no relationship with the secondary self-inductance. Otherwise, the OVR of the other two modes are bigger than the previously mentioned one. It is concluded that the critical inductance between the CISM-CCM and the IISM-CCM is the minimal secondary self-inductance to ensure the smallest output voltage ripple. At last, a design method to guarantee the minimum OVR within the scales of the input voltage and load are analyzed, and the minimum secondary self-inductance is proposed to minimize the OVR. Simulations and experiments are given to verify the results.

• Journal of IKEEE
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• v.24 no.4
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• pp.1180-1183
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• 2020

Recently, the daily life safety detection functionalities such as fall accident detection and burn danger detection are widely disseminated along with the development of IoT and smart home. These safety detection functionalities are mostly performed by artificial intelligence. However, simple accuracy measurement of the safety detection in laboratory environment is often far from practical performance in daily life environment. To mitigate this problem, this paper introduces two techniques, i.e. living lab and confusion matrix. Living lab is more than simple simulation of daily life environment, and it enables users to directly participate technology development and product design. Various performance measures induced from confusion matrix significantly help to evaluate the performance of artificial intelligence system for proper application purposes.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.2
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• pp.292-302
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• 2004

The purpose of this study was to evaluate thermal properties of lab gowns developed from the point of safety and work efficiency. We evaluated thermal and subjective responses of subjects wearing functional new lab gowns (Type B, C, D) and a popular lab gown on the market (Type A). Type B was a new lab gown made of woven fabric with functional cuffs. Type C was a new apron made of woven fabric with arm protectors. Type D was a new lab gown made of non-woven material with functional cuffs and openings around the armpits. Temperature in the climatic chamber was set at 19$^{\circ}$C as an indoor temperature in winter and at 24$^{\circ}$C in summer. There were no significant differences in rectal temperature and heart rate among four types of gowns and between two air temperatures for 120 min. Mean skin temperature was much higher in the type A and B than in He type C and D (p .05). In the 19$^{\circ}$C air, clothing microclimate temperature on the back was the highest in the type B and was the lowest in the type C (p .05). Clothing microclimate humidity was not significant differences among gowns. In subjective .esponses, subjects perceived that Type B was the warmest gown in the 19$^{\circ}$C and the hottest and more humid in the 24$^{\circ}$C than other gowns. Inversely, type C was the coolest gown among four gowns. Both in the 19$^{\circ}$C and in the 24$^{\circ}$C, the Type D had gained most responses of being comfortable. In conclusion, the temperature difference of 5$^{\circ}$C was more of an influencing factor than the difference from four types of lab gowns. Secondly, we recommend the manufacturers to make lab gowns with functional cuffs for safety purposes. Thirdly, the spread of the type of apron with arm protector will contribute to increase of the frequency of wearing in summer. Fourthly, it is necessary to study continuously about lab gowns with non-woven materials for researchers exposed to toxic chemical and biological materials.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2004.10a
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• pp.379-384
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• 2004

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.181-186
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• 2005

A ship runs with various modes of motion due to waves. Among the modes, roll mainly influences on the safety of cargos on the deck of container ship. In order to protect cargo shifting and turning, securing and lashing system are generally installed. In that case, it is necessary that the force and moment at the connection point of containers should be estimated. Therefore we derived mathematical equations to calculate the forces of securing points and lashing wires. Also we calculated those forces and moments about various lashing patterns.

• Geomechanics and Engineering
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• v.1 no.1
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• pp.85-96
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• 2009

The radius and coordinate of sliding circle are taken as searching variables in slope stability analysis. Genetic algorithm is applied for searching for critical factor of safety. In order to search for critical factor of safety in slope stability analysis efficiently and in a robust manner, some improvements for simple genetic algorithm are proposed. Taking the advantages of efficiency of neighbor-search of the simulated annealing and the robustness of genetic algorithm, a hybrid optimization method is presented. The numerical computation shows that the procedure can determine the minimal factor of safety and be applied to slopes with any geometry, layering, pore pressure and external load distribution. The comparisons demonstrate that the genetic algorithm provides a same solution when compared with elasto-plastic finite element program.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.377-382
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• 2005

A ship runs with various modes of motion due to waves. Among the modes, roll mainly influences on the safety of cargos on the deck of container ship. In order to protect cargo shifting and turning, securing and lashing system are generally installed. In that case, it is necessary that the force and moment at the connection point of containers should be estimated. Therefore we derived mathematical equations to calculate the forces of securing points and lashing wires. Also we calculated those forces and moments about various lashing patterns.

• Journal of Drive and Control
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• v.19 no.1
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• pp.34-42
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• 2022

Hydrostatic transmission (HST) comprises rotary parts, shafts, valve plate, swashplate, and servo pistons. Ensuring structural stability of each part of an HST has a significant impact on product safety. In this study, the structural stability of HST in agricultural machinery and industrial vehicles was analyzed using ANSYS software. For conservative evaluation, high-pressure conditions (35.5 MPa and 2 MPa pilot pressure) were applied as load conditions. The number of grids used in the calculations ranged from 0.4 to 0.8 million depending on modeling requirements. Structural analysis was performed for essential parts and safety factor was analyzed. All major parts of HST had a safety factor of ≥ 1.5. Thus, they were judged to be structurally safe. This study provides important information for designing an HST system.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.955-961
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• 2020

Lactic acid bacteria (LAB) have caused many microbiological incidents in the brewing industry, resulting in severe economic loss. Meanwhile, traditional culturing method for detecting LAB are time-consuming for brewers. The present review introduces LAB as spoilage microbes in daily life, with focus on LAB in the brewing industry, targeting at the spoilage mechanism of LAB in brewing industry including the special metabolisms, the exist of the viable but nonculturable (VBNC) state and the hop resistance. At the same time, this review compares the traditional and novel rapid detection methods for these microorganisms which may provide innovative control and detection strategies for preventing alcoholic beverage spoilage, such as improvement of microbiological quality control using advanced culture media or different isothermal amplification methods.