• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.179-184
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• 2018

In this paper, we have proposed the development of DC-DC converter for LRT power supply. First of all, we have studied converter technology, main functions and characteristics were determined. In also, the converter design was carried out to meet the system design conditions. Based on this design, converter simulation is performed to enable stable charging and discharging of the vehicle system. We have performed the Light-load test according to charge mode, discharge mode. As a result, the manufactured converter performance was verified through the load test, and it's stability was confirmed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.89-94
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• 2013

The fire testing performed for smoke detector model approval in Korea tests only one kind of fire smoke. A photoelectric spot-type smoke detector using Mie scattering is affected by the wavelength of light beam and the particle diameter. According to UL (Underwriters Laboratories Inc.) 268 standard, this paper analyze the characteristic of the response for a photoelectric spot-type smoke detector on sale in Korea using various fire smokes. Probability that the response time is included in non-defective range is 100% in paper fire, 90% in wood fire and 75% in flammable liquid fire, 90% in wood fire and 75% in flammable liquid fire. According to the estimation for population mean of the response time choosing a confidence level of 99%, a maximum of 19% for wood fire and that of 38% for flammable liquid fire are defective. As the result of analysis of smoke particle, this paper is found that these results are caused by the smoke particles are wide variations in size or have very black.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.185-193
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• 2021

The system needs to be modified to improve the performance of the aircraft in operation or to satisfy the requirements of related laws. Appropriate standards are required for the technical skills for remodeling the aircraft system, design verification for airworthiness of the aircraft, and supplemental type certification (STC) certification procedures for type certification. This study analyzes the current status and demand of domestic aircraft remodeling, examines the current supplementary type certification procedure, and diagnoses the problem. In addition, as a result of researching measures to improve remodeling technology and certification capabilities to extend the life of the aircraft, improvements in the education system were derived to improve the domestic additional type certification process, such as approval of remodeling agencies and appointment of qualifications for each professional technician.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.3
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• pp.383-390
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• 2010

This study is currently giving priority to developing the ship's ballast water treatment system using ozone (Ozone BWTS). The Ozone BWTS was tested in a full scale land-based mobile barge to evaluate performance according to the IMO G8 Guidelines. Test cycles using the mobile-barge were conducted in seawater and brackish water in the vicinity of the Port of Busan and Nakdong River, Republic of Korea. All tests were conducted according to the requirements of the G8 Guidelines. Test results show that the Ozone BWTS meets the Ballast Water Performance Standard contained in Regulation D-2 of the IMO Ballast Water Management Convention, as well as all of the operational, safety, and environmental testing requirements of the G8 Guidelines, as required for type approval of IMO. The study results show that the Ozone BWTS is capable of meeting the Ballast Water Performance Standard under Regulation D-2 of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and also the more stringent standards being proposed under US legislation.

• Fire Science and Engineering
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• v.23 no.3
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• pp.85-92
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• 2009

This paper studied on the development of standardization tester for the field inspection of the rate of rise spot type heat detector. It was to find the problems of the 4 type's testers such as A type (electric bulb type), B type (halogen lamp type), C type (heating coil type), D type (fumigator type) which were used to check of the rate of rise spot type heat detector in inspection for the fire protection. To identify those problems, this paper described about the development of standardization tester for the field inspection of the rate of rise spot type heat detector and that have the function of auto setting temperature more $30^{\circ}C$ higher than room temperature and keep the constant temperature. And keep the constant wind velocity of 85cm/sec. Performance verification results of the developed prototype that had same conditions such as the sensitivity test conditions at the type approval of the rate of rise spot type heat detector.

• Journal of the Korean Home Economics Association
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• v.41 no.6
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• pp.13-28
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• 2003

The purposes of this study were to identify money altitudes of college students and to examine both socio-economic characteristics and clothing purchase behaviors by different money attitudes. For this study, guestionnaires completed by 2-year and 4-year college students (n=426) were analyzed by factor analysis, cluster analysis, X²- test, and ANOVA. The results of this study were as follows: First, the money attitudes were composed of five factors and they were categorized by three clusters: cluster of considering the money as a tool for future safety, a way of approval and filling up emotions, and inclination toward stinginess and distrust. Second, the factors which were associated with money attitudes were academic level, education level of parents, household income, students' own income, and the economic level of their households. Third, in each type of attitudes, the clothing purchase behavior had four steps of decision making: problem recognition, information search, evaluation of alternatives, and the purchase. There were significant differences in the clothing purchase behavior among the money attitude styles.

• Safety and Health at Work
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• v.1 no.2
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• pp.140-148
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• 2010

Objectives: Determining the work-relatedness of lung cancer developed through occupational exposures is very difficult. Aims of the present study are to develop a decision tree of occupational lung cancer. Methods: 153 cases of lung cancer surveyed by the Occupational Safety and Health Research Institute (OSHRI) from 1992-2007 were included. The target variable was whether the case was approved as work-related lung cancer, and independent variables were age, sex, pack-years of smoking, histological type, type of industry, latency, working period and exposure material in the workplace. The Classification and Regression Test (CART) model was used in searching for predictors of occupational lung cancer. Results: In the CART model, the best predictor was exposure to known lung carcinogens. The second best predictor was 8.6 years or higher latency and the third best predictor was smoking history of less than 11.25 pack-years. The CART model must be used sparingly in deciding the work-relatedness of lung cancer because it is not absolute. Conclusion: We found that exposure to lung carcinogens, latency and smoking history were predictive factors of approval for occupational lung cancer. Further studies for work-relatedness of occupational disease are needed.

• The Journal of KAIRB
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• v.5 no.1
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• pp.14-20
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• 2023

Purpose: To obtain fundamental data on selection tools for an internal audit and develop a new guideline. We scored the indicated points from the internal audit, identified the research progress and problems that occurred, and confirmed the validity of the risk factors involved. Methods: Of the 63 internal audits conducted by Keimyung University Dongsan Hospital from 2014 to 2021, we analyzed 55 clinical trials with an inspection checklist. We excluded 8 that failed to transfer data and refused to comply with the internal audit. The statistical summary of the collected data was verified and interpreted by using frequency analysis and a chi-square test. Result: Of total 55 cases included in the internal audit, sponsor-initiated trial (SIT) was 63.6% (vs. investigator-initiated trial [IIT]), clinical trial for investigational drug was 71.0% (vs. nonclinical or clinical trial for investigational device), domestic multicenter trial was 60.0% (vs. single center or multinational multicenter trial), and trial requisition for MFDS approval was 69.1% (vs. exception for MFDS approval). The 10 areas of the clinical trial inspection checklist (reports, protection of subjects, compliance with protocols, records, management of investigational drug and/or device, delegation of duties, qualification of investigators, management of specimen, contract-agreement and approval of protocols, and preservation of recorded documents) were weighted between 2 to 5 points. The average of the total points was 16.09±13.2 and 20 clinical trials were above the average. As a result of comparing the average of the total points weighted by year, the highest score was in 2020. The 4 factors that play significant roles in determining the internal quality were (1) principal subjects that initiated the clinical trials (p=0.049), (2) type (p=0.003), (3) phase of clinical trials (p=0.024), and (4) number of registered subjects reported at the time of continuing deliberation (p=0.019). Of the 10 areas of the clinical trial inspection checklist, 'record' was the most inappropriate and insufficient. We found more indicated points; the quality of performance declined in IIT, nonclinical trials, and other clinical trials that were not in phase I1-IV4, and the study of more than 30 registered subjects at the time of continuing review. Conclusion: If an institution has an internal audit selection tool that reflects the aforementioned risk factors, it will be possible to effectively manage high-risk studies; thereby, contributing to an efficient internal audit and improving the quality of clinical trials.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.34-42
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• 2018

In order to minimize the deformation of asphalt concrete track(ACT) and ensure the structural safety, a wide type concrete sleeper is necessary to distribute vehicle loading and reduce the exposure of the asphalt roadbed. In this research, the wide prestressed concrete(PSC) sleeper for ACT was developed through the shape design and the structural safety was reviewed using finite element analysis. Furthermore, static test, dynamic test and fatigue test were carried out according to EN13230-2 to verify the design appropriateness of the wide PSC sleepers for ACT. The performance test showed that the developed wide PSC sleeper for ACT meets all the performance requirements by European standard.

• Journal of Platform Technology
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• v.9 no.1
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• pp.32-39
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• 2021

Existing environmental measuring devices mainly focus on electromagnetic wave and eco-friendly product certification and durability test, and sensor reliability verification and verification of measurement data are conducted mainly through sensor performance evaluation through type approval and registration, acceptance test, initial calibration, and periodic test. This platform has established an ICT-based environmental monitoring sensor reliability verification system that supports not only performance evaluation for each target sensor, but also a verification system for sensor data reliability. A sensor board to collect sensor data for environmental information was produced, and a sensor and data reliability evaluation and verification service system was standardized. In addition, to evaluate and verify the reliability of sensor data based on ICT, a sensor data platform monitoring prototype using LoRa communication was produced, and the test was conducted in smart cities. To analyze the data received through the system, an optimization algorithm was developed using machine learning. Through this, a sensor big data analysis system is established for reliability verification, and the foundation for an integrated evaluation and verification system is provide.