• Nuclear Engineering and Technology
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• v.35 no.2
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• pp.154-164
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• 2003

The explicit consideration of different pressurization rates in estimating the probabilities of containment failure modes has a profound effect on the confidence of containment performance evaluation that is so critical for risk assessment of nuclear power plants. Except for the sophisticated NUREG-1150 study, many of the recent containment performance analyses (through Level 2 PSAs or IPE back-end analyses) did not take into account an explicit distinction between slow and fast pressurization in their analyses. A careful investigation of both approaches shows that many of the approaches adopted in the recent containment performance analyses exactly correspond to the NUREG-1150 approach for the prediction of containment failure mode probabilities in the presence of fast pressurization. As a result, it was expected that the existing containment performance analysis results would be subjected to greater or less conservatism in light of the ultimate failure mode of the containment. The main purpose of this paper is to assess potential conservatism of a plant-specific containment performance analysis result in light of containment failure mode probabilities.

• Nuclear Engineering and Technology
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• v.36 no.5
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• pp.388-402
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• 2004

A phenomena identification and ranking table(PIRT) was developed for a main steam line break (MSLB) event for the Advanced Power Reactor-1400 (APR-1400). The selectee event was a double-ended steam line break at full power, with the reactor coolant pump running. The developmental panel selected the fuel performance as the primary safety criterion during the ranking process. The plant design data, the results of the APR-1400 safety analysis, and the results of an additional best-estimate analysis by the MARS computer code were used in the development of the PIRT. The period of the transient was composed of three phases: pre-trip, rapid cool-down, and safety injection. Based on the relative importance to the primary evaluation criterion, the ranking of each system, component, and phenomenon/process was performed for each time phase. Finally, the knowledge-level for each important process for certain components was ranked in terms of existing knowledge. The PIRT can be used as a guide for planning cost-effective experimental programs and for code development efforts, especially for the quantification of those processes and/or phenomena that are highly important, but not well understood.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2531-2546
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• 2021

For several years, virtual reality (VR) and augmented reality (AR) technologies have been improving. However, some hurdles remain that slow down the distribution of VR and AR devices, such as head-mounted display (HMD), and related consumer content. One issue is VR motion sickness, which has been experienced by users using 360 degree VR content via HMD. This paper discusses the related international standardization work that classifies the factors causing VR sickness, and proposes the process for VR sickness level evaluation. Among the factors causing VR sickness, many research institutes regard minimizing MTP (Motion-to-Photon) latency as the key enabler to mitigate VR sickness. Thus, this paper introduces research trends of MTP latency measurement and MTP latency mitigation. This paper categorizes the research on MTP latency measurement into 2 categories of hardware-based approach and software code-level approach. The 2 approaches have different pros and cons depending on use-case, purpose, and architecture of each multimedia system. The pros and cons are addressed in this paper. Additionally, the research on mitigating MTP latency with diverse strategies such as proactive computing, caching, and edge server technology is explained, and compared to conventional technologies, shows improved performance.

• Korean Journal of Veterinary Research
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• v.61 no.1
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• pp.7.1-7.7
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• 2021

The levels of aflatoxin (AFT) and ochratoxin (OCT) were assessed at different seasons in raw materials, different feed manufacture processing stages, and animal feeds in feed mills in Korea implementing the hazard analysis and critical control point (HACCP) system. Two hundred samples were collected in all four seasons from five feed mills implementing the HACCP system and examined for AFT and OCT contents. The AFT and OCT levels were analysed by using HPLC method to provide information on raw material and product stage. The AFT content of raw ingredients in the spring season was highest in corn gluten (3.84 ppb) and lowest in corn (1.82 ppb) The AFT content of corn was highest in the winter season (2.17 ppb). The content of OCT in wheat was highest in the winter season. The amounts of AFT and OCT at processing stages were higher than in the raw materials or feed. In particular, AFT content was higher in the transfer stage (3.88 ppb) than in the mixing (2.86 ppb) or filling stages (3.45 ppb) in the summer season. The means of AFT and OCT level in laying hen feed was 3.41 ppb and 1.14 ppb for broiler feed, respectively. The means of AFT and OCT level in and broiler feeds was 3.44 ppb and 1.17 ppb for broiler feed, respectively.

• The Research Journal of the Costume Culture
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• v.30 no.2
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• pp.319-329
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• 2022

This study started from the practical need for a career experience program in the fashion major that is creative and responds to current methodologies. The purpose of this study is to propose a fashion work experience program that combines digital technology and practical experience. The research methods and procedures were as follows: fashion items and wearable devices were selected, the LED smart bag program was developed, and it was executed. A total of 123 students participated in the program, and a satisfaction survey was conducted after observation and oral evaluation. All of the participants completed the LED smart bag processes of design ideation, material selection, production, and styling using an eco-bag (one of the fashion items and as an LED wearable device). As a result of the participants' satisfaction (on a 5-point scale), most items showed a high level of satisfaction of 4.39 points or more. The smart bag program was evaluated to increase interest based on the time allotted and the students' level and to bolster their understanding of, and interest in, the fashion major. Therefore, this study is expected to be baseline to explore diversification of the fashion major work experience program, in order to create interest in the fashion major based on creative convergence competency.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.569-577
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• 2000

The position of tobacco leaves is affluence to the quality. To evaluate its quality, sample leaves was collected according to the position of attachment. In Korea, the position was divided into four classes such as high, middle, low and inside positioned leaves. Until now, the grade of standard sample was determined by human expert from korea ginseng and tobacco company. Many research were done by the chemical and spectrum analysis using NIR and computer vision. The grade of tobacco leaves mainly classified into 5 grades according to the attached position and its chemical composition. In high and low positioned leaves shows a low level grade under grade 3. Generally, inside and medium positioned leaf has a high level grade. This is the basic research to develop a real time tobacco leaves grading system combined with portable NIR spectrum analysis system. However, this research just deals with position recognition and grading using the color machine vision. The RGB color information was converted to HSI image format and the sample was all investigated using the bundle of tobacco leaves. Quality grade and position recognition was performed through well known general error back propagation neural network. Finally, the relationship about attached leaf position and its grade was analyzed.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.349-358
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• 2023

The Satellite-Based Augmentation System (SBAS) plays a significant role in the fields of aviation and navigation: it corrects signal errors of the Global Navigation Satellite System (GNSS) and provides integrity information to facilitate precise positioning. These SBAS systems have been adopted as international standards by the International Civil Aviation Organization (ICAO). In recent SBAS system design, the Minimum Operational Performance Standards (MOPS) defined by the Radio Technical Commission for Aeronautics (RTCA) must be followed. In October 2014, South Korea embarked on the development of a Korean GPS precision position correction system, referred to as Korea Augmentation Satellite System (KASS). The goal is to achieve APV-1 Standard of Service Level (SoL) service level and acquisition of CAT-1 test operating technology. The first satellite of KASS, KASS Prototype 1, was successfully launched from the Guiana Space Centre in South America on June 23, 2020. In December 2022 and June 2023, the first and second service signals of KASS were broadcasted, and full-scale KASS correction signal broadcasting is scheduled to start at the end of 2023. The aim of this study is to analyze the precision of both the GNSS system and KASS system by comparing them. KASS is also compared with Japan's Multi-functional Satellite Augmentation System (MSAS), which is available in Korea. The final objective of this work is to validate the usefulness of KASS correction navigation in the South Korean operational environment.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1725-1732
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• 2024

In nuclear power plants, reactor coolant leakage can occur due to various reasons. Early detection of leaks is crucial for maintaining the safety of nuclear power plants. Currently, a detection system is being developed in Korea to identify reactor coolant system (RCS) leakage of less than 0.5 gpm. Typically, RCS leaks are detected by monitoring temperature, humidity, and radioactivity in the containment, and a water level in the sump. However, detecting small leaks proves challenging because the resulting changes in the containment humidity and temperature, and the sump water level are minimal. To address these issues and improve leak detection speed, it is necessary to quantify the leaks and develop an artificial intelligence-based leak detection system. In this study, we employed bidirectional long short-term memory, which are types of neural networks used in artificial intelligence, to predict the relative humidity in the leakage area for leak quantification. Additionally, an optimization technique was implemented to reduce learning time and enhance prediction performance. Through evaluation of the developed artificial intelligence model's prediction accuracy, we expect it to be valuable for future leak detection systems by accurately predicting the relative humidity in a leakage area.

• Analytical Science and Technology
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• v.23 no.2
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• pp.196-204
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• 2010

In this study, the following concentrations of some PAHs (Polycyclic Aromatic Hydrocarbons) were investigated; [benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, indeno(1,2,3-c,d)pyrene] in processed foods (n=165) and cooked meats (n=45) and established the analytical method by characteristics of processed foods. The methodology involved extraction (alkali digestion, liquid-liquid extraction, microwave extraction), clean-up on Sep-Pak Florisil Cartridges and determination by HPLC/FLD (High Performance Liquid Chromatography/Fluorescence Detector). The recovery of overall method for 8 PAHs spiked into these products ranged from 92 to 103%. The mean level of detected foods was found to be benzo(b)fluoranthene $0.9\;{\mu}g/kg$ in smoked salmon, benzo(b)fluoranthene $1.0\;{\mu}g/kg$, benzo(k)fluoranthene $0.3\;{\mu}g/kg$, benzo(a)pyrene $0.9\;{\mu}g/kg$ in dried banana, benzo(b)fluoranthene $0.2\;{\mu}g/kg$, benzo(k)fluoranthene $0.1\;{\mu}g/kg$, benzo(a)pyrene $0.2\;{\mu}g/kg$ in smoked chicken, benzo(b)fluoranthene $1.3\;{\mu}g/kg$, benzo(k)fluoranthene $0.3\;{\mu}g/kg$, benzo(a)pyrene $0.9\;{\mu}g/kg$ in charcoal grilled pork, respectively.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.429-437
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• 2010

As Web technology and functions have recently changed to a user-focused paradigm, new studies are being conducted to construct dynamic learning content that enables the learner's participation and continuous learning in the field of e-learning research and design. This paper covers a study on the degree of difficulty in learner-focused dynamic learning contents to provide efficient learning environments for its adaptation to e-learning 2.0. This study suggests DLA (Dynamic Level Adjustment) to provide learner-focused contents. The suggested system will be a guideline to control and adopt learning content that can be easily applied to the environmental change, and more in-depth future research can be performed by using the system. A dynamic learning content model was made to recognize various learning patterns of learners as a result of the performance evaluation.