• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.1-12
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• 2018

The objectives of this study were to develop a system linking hydrologic and water quality models considering the mechanisms of agricultural reservoir and paddy cultivation and to evaluate whether the developed system simulates hydrologic and water quality processes better than a hydrologic model that do not consider the mechanisms. The system consisted of Hydrological Simulation Program-Fortran (HSPF) as a watershed model, Module-based hydrologic Analysis System for Agricultural watersheds (MASA) as reservoir water balance model, and Chemical, Runoff and Erosion from Agricultural Management System-Paddy (CREAMS-PADDY) as a hydrologic and water quality model for paddy fields. This study carried out on the Seolseong-Cheon watershed in Icheon, and the water level and water quality had been monitored for two years at the outlet of the watershed. According to the results of this study, the performance of the simulation using HSPF-MASA-CREAMS-PADDY system was better than others, but they did not show a statistically significant difference. This seemed to be due to the uncertainty of the farming data and the water quality data of the reservoir. Therefore, if accurate input data for the system is obtained, HSPF-MASA-CREAMS-PADDY system could be used to model an agricultural watershed to obtain more realistic results. The results of this study could be utilized to the modeling of agricultural watersheds in Korea where paddy rice cultivation is dominant.

• Journal of the Korean Institute of Gas
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• v.13 no.2
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• pp.36-40
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• 2009

In this study, we surveyed 544 drivers, who had taken the education course for autogas car drivers, to figure out their safety awareness status including the recognition of hazards of gas leaking from autogas cars and response attitude toward them. As a result of the survey, we found out that 63% of the responders recognized the hazards of gas leakage and 79% preferred parking in the aboveground areas. For the necessity of introducing restrictions on autogas cars parking in underground lots, 58% of all responders answered yes while 71% of the responders aged over fifties and 73% of them who responded to have known the hazards of parking in underground answered in the affirmative. Furthermore, we found out that responders who had recognized the hazards preferred aboveground parking areas, and the responders who had preferred the aboveground recognized the hazards of parking autogas cars underground and felt the necessity of restricting them from parking in underground relatively high. Through the analysis of these results, we can analyse that the drivers who are aware of the hazards of gas leakage have higher safety attitude for hazards than the other drivers who are not aware of them.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.102-107
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• 2006

Construction accidents have not decreased in spite of much effort such as new work methods, education and research related to safety works. Specially, many fatal accidents happened in construction works which involve the apartment, building, school, church, hotel, hospital, bank work and the other works. These accidents are mainly caused by unanticipated risk factors. From these reasons, this study researched fatal accidents which happened in construction works during last 13 years($1992{\sim}2004$) and analyzed the input workers and a work period of construction work. According to the input workers and a work period, the results are as following. During 13years($1992{\sim}2004$), the fatal accidents, related to the construction work, were happened to the 1,977 cases. These results were occupied the 21.32% of the total industry accidents. According to the result of the construction, the fatal accident rate of a concrete form work was the highest rate of 16.24% (321 cases) and a temporary work, a steel frame work was the each rate of 12.39%(245 cases), 10.07%(199 cases). Comparing to other work types, the fatal accident rate of those three work types(concrete form work, temporary work, steel work) was represented highly. We surveyed input workers and work period of construction work site. From the result of survey, input workers of a concrete form work were occupied with 13,720. The risk rate of the work type, which was considered input workers and work period, was represented 0.3622(a steel frame work), 0.1142(a temporary work), 0.0782(a tower crane) and 0.0772(a concrete work).

• Journal of the Korean Society for Heat Treatment
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• v.12 no.4
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• pp.303-312
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• 1999

An investigation of the CrMoV rotor steel weldment which experienced by cyclic thermal aging heat treatment and as-received condition was performed. This evaluation was carried out to confirm whether this type of weldment is appropriate for the service environment in terms of microstructural examinations, microhardness measurements and tensile tests. The cyclic thermal aging heat treatment, containing continuous heating and cooling thermal cycle was programmed to simulate the real rotor service condition. The heat treatment was performed for 40 cycles(5920hrs). The results indicated that the weldment was composed of 4 different regions such as heat affected zone of the base metal, butter weld(initial weld), full thickness weld(final weld) and the base metal. The double welding process was applied to eliminate the susceptibility of reheat cracking at heat affected zone of base metal. The grain refinement at the HAZ due to the welding process could reduce the possibility of cracking susceptibility, but its tensile properties was appeared to be low due to the weld metal in as-received condition. The benefit effect, grain refinement was extended with carbides coarsening during the cyclic thermal aging heat treatment. However the poor mechanical properties of the weldment was more degraded as undergoing the heat treatment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.322-328
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• 2018

The purpose of this study is to examine the performance of Problem-Based Learning (PBL) based on Google Classroom(GC). GC is an easy and free online learning that plays an important role in education and training recently. Students become increasingly independent in self-directed learning while sharing ideas and resources, transferring knowledge actively across domains and researching for solutions to the given problem in PBL. Students can check the submission date on the task page and start the task with a single click, and teachers can quickly check if the task is complete, and score it directly from GC. Designed The Evaluation of Problem -Based Learning based on GC in this study. The students read the given materials and identify the purpose of the subjects and selected the learning issues, investigated them. After then they discuss the subjects and make the reports. The students work to study them with research papers, books and internet materials. The research findings showed that PBL based on GC was effective in learning together. Students had positive attitude in their PBL learning environment. This study suggests it is possible that the development of PBL Evaluation on the GC.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.417-428
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• 2017

Diseases caused by foodborne or waterborne pathogens are emerging. Many pathogens can enter into the viable but nonculturable (VBNC) state, which is a survival strategy when exposed to harsh environmental stresses. Pathogens in the VBNC state have the ability to evade conventional microbiological detection methods, posing a significant and potential health risk. Therefore, controlling VBNC bacteria in food processing and the environment is of great importance. As the typical one of the gram-negatives, Escherichia coli (E. coli) is a widespread foodborne and waterborne pathogenic bacterium and is able to enter into a VBNC state in extreme conditions (similar to the other gram-negative bacteria), including inducing factors and resuscitation stimulus. VBNC E. coli has the ability to recover both culturability and pathogenicity, which may bring potential health risk. This review describes the concrete factors (nonthermal treatment, chemical agents, and environmental factors) that induce E. coli into the VBNC state, the condition or stimulus required for resuscitation of VBNC E. coli, and the methods for detecting VBNC E. coli. Furthermore, the mechanism of genes and proteins involved in the VBNC E. coli is also discussed in this review.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.59-66
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• 2015

This study investigated the recognition difference among construction work participants for the assignment of the safety and health management responsibility to a client by survey. Recently, there were some studies for the client's responsibility and duty and they suggested the client-initiative safety and health management system in order to prevent construction accidents. To supplement the existed studies, this study surveyed various construction participants such as clients, safety managers, construction managers, supervisors, others. The clients and construction managers considered the contractor as most important person to prevent construction accidents, but the safety managers and supervisors considered the client. For the opinion that the assignment of the safety and health management duty to a client is helpful, safety managers were agreed with the most. However, the clients showed the lowest agreement. The reasons that the negative opinion for the assignment of client's the safety and health management were different between clients and other construction parties. Since, clients showed large difference to other construction participants for the recognition of works' safety and health, the education about the works' safety and health management should be continuously performed for clients to have correct recognition for works' safety and health.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.565-570
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• 2016

User requirements for access and authentication increase daily because of the diversification of the Internet of Things (IoT) and social structures. The increase in authentication needs requires the generation of new passwords. Users want to utilize the same passwords for memorization convenience. However, system administrators request each user to use different passwords, as well as passwords that include special symbols. Differnet passwords and including special symbols passwords seem to exceed the tolerance range within your memorization skills. It fetches a very negative consequences in terms of password management. This paper proposes a preference symbol password system that does not require memorization by users. First, a survey is conducted to prove statistical safety, and based on this, an evolution-type password system that uses preference symbols is designed. Preference symbol passwords show superiority with respect to installation cost and convenience, compared with conventional non-memorizing password systems such as biometrics, keystrokes, and mouse patterns.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.493-499
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• 2015

In Korea mobile phone subscribers exceeded 1 million people in 1995, and ten million people in 1998. Prevalence of the mobile phone increased dramatically over 110% compared to the population. Almost every family members including children uses more than one mobile terminal. Mobile phone is obviously more necessary good than washer, vacuum cleaner and passenger car. Our daily life are conveniently positioned with mobile communication, but communication related costs including the price of the device and service charges become a big burden on the household. But the government does not seem to do the right role at the right time to prevent the market failure to maximize consumer welfare and social welfare through supporting fair competition. This principal-agent problem issues of mobile communication policies will be understood in perspective of public choice against joint use of the mobile communication network, number portability, separation of phone distribution and phone service, network neutrality, mobile phone subsidy since the early 1990s when mobile phone service was introduced in Korea.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.189-196
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• 2016

We propose a virtual sailor training platform which supports emergency drills for ship's fire in virtual environment. Proposed platform not only enhances training efficiency by providing immersiveness, but also enables a consolidated virtual training due to the network-based multiplayer capabilities. Based on the offline fire simulation results using FDS and CFAST the platform visualizes a realistic fire spread in real-time. The training platform on the basis of the fire training material of the maritime safety education institute induces equipment proficiency and environment adaptation throughout immersive virtual environment in addition to procedure proficiency as well. In the implementation we showed that the equipment and environment controls and telepresence improve the training proficiency and enable collaborative virtual training that participates multiple trainees and induces cooperation for a common goal. Implementation of the platform demonstrated the skill mastery capability of the drill such as efficient fire apparatus controls and passenger controls.