• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.5
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• pp.486-493
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• 2024

Lighting has been used for a long time as a medium to convey brightness from darkness, and through incandescent lamps and fluorescent lamps, LED light sources have now become the standard in the lighting industry. Recently, the lighting equipment industry has been undergoing rapid digital transformation, starting with smart lighting, and is evolving into smart lighting customized for individuals and spaces through the development of IoT technology, cloud-based services, and data analysis. However, the blue light emitted from digital devices (computers, smartphones, tablets, etc.) or LED lights stimulates the melanopsin in the optic ganglion cells in the retina of the eye, which in turn stimulates the secretion of melatonin through the pineal gland, which regulates the secretion of melatonin. This can reduce sleep quality or disrupt biological rhythms. This interaction between blue light and melatonin has such a significant impact on human sleep patterns and overall health that it is essential to reduce exposure to blue light, especially in the evening. Human-centered lighting refers to lighting that takes into account the effects of light on the physical and mental areas, such as human activity and awakening, improvement of sleep quality, and health management. Many research institutes study the effects in the visible area and the non-visible area. By studying the impact, it is expected to improve the quality of human life. In this study, we plan to study ways to implement human-centered lighting by collecting sunrise and sunset data and linking commercialized LED packages and control devices with open-source hardware.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.375-383
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• 2020

This study aimed to propose a methodology for quantitatively analyzing problems resulting from the performance and combination of the ionization chamber when using an automatic exposure control (AEC) and to optimize the performance of the digital radiography (DR). In the experimental method, the X-ray quality of the parameters used for the examination of the abdomen and pelvis was evaluated by percentage average error (PAE) and half value layer (HVL). Then, the stability of the radiation output and the image quality were analyzed by calculating the entrance surface dose (ESD) and entropy when the three ionization chambers were combined. As a result, all of the X-ray quality of the digital radiography used in the experiment showed a percentage average error and a half value layer in the normal range. The entrance surface dose increased in proportion to the combination of chambers, and entropy increased in proportion to the combination of ionization chambers except when three chambers were combined. In conclusion, analysis using entrance surface dose and entropy was found to be a useful method for evaluating the performance and combination problems of the ionization chamber, and the optimal performance of the digital radiography can be maintained when two or less ionization chambers are combined.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.304-313
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• 2018

Agricultural land reclamation in Saemangeum tidal land project is mostly planned to be completed by 2020. Irrigation water for the land is required to be prepared by that time. However, water quality for the irrigation sources is barely meet the target concentration. This paper described the reduction effect of and policy consideration for best management practices (BMPs) which were fertilizer prescription by soil test (SO#1), mixed application of SO#1 and 3 (SO#2), drainage gate control (SO#3), time-release fertilizer application (SO#4), and control (CT). Reduction of paddy runoff was relatively higher in SO#3 (25%) and SO#1 (27%) while lower in SO#4 (9%) and SO#2 (7%) than that in CT. In addition, farmers promised to follow the BMP guidelines but they didn't because of the several problems caused for the BMPs implementation. Thus, it recommended developing an automated control of irrigation gate and paddy water depth and supporing farmers for NPS pollution control and irrigation water reduction.

• Korean Journal of Comparative Education
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• v.18 no.4
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• pp.27-55
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• 2008

Since quality assurance and enhancement (QAE) raises the fundamental issue of the survival of higher education institutions and national competitiveness, guides on quality assurance (QA) are popular both domestically and worldwide. Despite the focus in many countries on trying to establish and implement QA systems, no clear investigation has been conducted on what actually happens in the institutions. Therefore, the present study examines the quality control system of the UK at an institutional level by focusing on the case of Scotland QAE. As Scottish QAE especially emphasizes student engagement and quality culture, this study investigates the present QAE situation in the institution and current ideas for better future practices by analyzing the perceptions of internal stakeholders' from the University of Edinburgh, School of Education, based on the stakeholder theory and implications for other contexts. The stakeholder analysis results demonstrate the successful application of QAE with a high level of understanding and stakeholder interest. However, the current strategy is missing certain opportunities for staff and students. Therefore, further information disclosure, formative evaluation, better communication and administrational supports are required for improved practice.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.64-69
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• 2007

Motion control of the system is a position control of motor. Motion control of an uncertain robot system is considered as one of the most important and fundamental research directions in the robotics. Some distinguished works using linear control, adaptive control, robust control strategies based on computed torque methodology have been reported. However, it is generally recognized within the control community that these strategies suffer from the following problems : the exact robot dynamics are needed and hard to implement, the adaptive control cannot guarantee the performance during the transient period for adaptation under the variation, the robust control algorithms such as the sliding mode control need information on the bounds of the possible uncertainty and disturbance. And it produces a large control input as well. In this dissertation, a motion control for the unmanned intelligent robot system using disturbance observer is studied. This system is affected with an impact vibration disturbance. This paper describes a stable motion control of the system with the consideration of external disturbance. To obtain the stable motion independently against the external disturbance, the disturbance rejection is strongly required. To address the above issue, this paper presents a Disturbance OBserver(DOB) control algorithm. The validity of the suggested DOB robust control scheme is confirmed by several computer simulation results. And the experiments with a motor system is performed to give the validity of applicability in the industrial field. This results make the easier implementation of the controller possible in the field.

• Korean Journal of Medicinal Crop Science
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• v.24 no.2
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• pp.143-151
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• 2016

Background: The public has increasing concerns about herbal crops owing to insufficient information on biological hazards such as foodborne pathogens. Therefore, the objective of this study is the development of a herbal crop quality control system through monitoring with biological hazard analysis. Today, it is estimated that millions of people become ill every year from food contamination. The public demands agricultural products of stable and consistent quality. Governments have the responsibility of establishing the standards, legislation and enforcement programs necessary to control food quality and safety. However, research on the biosafety of herbal crop products is still insufficient. Therefore, the implementation of monitoring systems with high standards is critical for public safety. Methods and Results: In this study, we collected 52 samples of herbal crop products, and conducted both quantitative and qualitative biological hazard analysis. With biological hazard analysis, aerobic bacteria, Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. could be detected. Conclusions: Herbal crops were found to be contaminated with aerobic bacteria at $3.69{\pm}0.32log\;CFU/g$. Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. were not detected in any of the samples. This research suggests that continuous monitoring of biological hazards is required to improve the quality of herbal crops.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.227-234
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• 2018

Concrete mix design controls the various concrete properties such as workability and strength. Fresh concrete requires workability and the hardened concrete requires compressive strength. If using the concrete from different supplier concurrently, the concrete placed can show different properties unlike originally designed. However most of construction sites place the concrete from several companies. One of the predictable problems is whether the ultimate performance of concrete achieves the originally designed performance after placing the concrete from several companies. Therefore this research aims to keep the concrete quality in the above cases. This research has been done through literature review, questionnaire and the verification at the sample construction site. A literature review describes the general characteristics and quality control of concrete and a questionnaire describes the awareness and implementation of Korean Construction Specification(KCS). The production capacity and the delivery capacity of concrete suppliers is smaller than the daily quantity required on the sample site, therefore the placing of the concrete with different mixing ratio is inevitable and it can not keep the KCS. As a conclusion, this research proposed 5 alternatives and one of them has been adopted, i.e. to unify the concrete mix design of multiple concrete suppliers.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.878-888
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• 2022

Objective: To investigate the clinical impact of a quality improvement program including dedicated emergency radiology personnel (QIP-DERP) on the management of emergency surgical patients in the emergency department (ED). Materials and Methods: This retrospective study identified all adult patients (n = 3667) who underwent preoperative body CT, for which written radiology reports were generated, and who subsequently underwent non-elective surgery between 2007 and 2018 in the ED of a single urban academic tertiary medical institution. The study cohort was divided into periods before and after the initiation of QIP-DERP. We matched the control group patients (i.e., before QIP-DERP) to the QIP-DERP group patients using propensity score (PS), with a 1:2 matching ratio for the main analysis and a 1:1 ratio for sub-analyses separately for daytime (8:00 AM to 5:00 PM on weekdays) and after-hours. The primary outcome was timing of emergency surgery (TES), which was defined as the time from ED arrival to surgical intervention. The secondary outcomes included ED length of stay (LOS) and intensive care unit (ICU) admission rate. Results: According to the PS-matched analysis, compared with the control group, QIP-DERP significantly decreased the median TES from 16.7 hours (interquartile range, 9.4-27.5 hours) to 11.6 hours (6.6-21.9 hours) (p < 0.001) and the ICU admission rate from 33.3% (205/616) to 23.9% (295/1232) (p < 0.001). During after-hours, the QIP-DERP significantly reduced median TES from 19.9 hours (12.5-30.1 hours) to 9.6 hours (5.7-19.1 hours) (p < 0.001), median ED LOS from 9.1 hours (5.6-16.5 hours) to 6.7 hours (4.9-11.3 hours) (p < 0.001), and ICU admission rate from 35.5% (108/304) to 22.0% (67/304) (p < 0.001). Conclusion: QIP-DERP implementation improved the quality of emergency surgical management in the ED by reducing TES, ED LOS, and ICU admission rate, particularly during after-hours.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.3
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• pp.49-56
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• 1993

This paper describes design and implementation of signal transmission system using LCX as communication media, which has characteristics of high reliability easy for expansion and complex transmission of voice, data and video signal in Electric culvert. In this system, we estimated system performance as result of variable transmission characteristics test. In case of voice signal, transmission loss characteristics improved 5-10(dB] than designed Values in received signal level. In the test of speech quality estimation, we obtained satisfactory result as speech intensity = 3 (QSA value), speech atriculation = 4 (QRK value). As for data and video signal transmission, communication success rates were 981% 1 in monitoring and control functional test. As a result of transmission characteristics test in transmission line and system, transmission range by LCX communication system without repeater can reach in 6Km. This paper presents basic construction method using LCX communication system for total management in Electric culvert.

• The Journal of Society for e-Business Studies
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• v.9 no.1
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• pp.285-301
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• 2004

Public service provision through internet is one of major parts for e-government implementation. It is essential to link the internal administrative network with internet to provide the services through internet and to support kiosks through internet, which should result in critical issues for security. A relay server, as a front server for the public service processing system and a web server, a control server for kiosks, are placed between the public service processing system and kiosks to solve those security issues. It is the way to solve security issues through protecting direct communication between the public service processing system and a web server and authenticating a relay server and a web server through authentication process. In the implementation of the system this paper provide a design for an architecture model of the public service processing system through internet, which are aiming to develop high level of the quality system effectively, to reduce the risk of initial stage of development, and to reduce the incurring cost due to reworks.