• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.452-459
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• 2023

The core power control is an important issue for the study of dynamic characteristics in China initiative accelerator driven subcritical system (CiADS), which has direct impact on the control strategy and safety analysis process. The CiADS is an experimental facility that is only controlled by the proton beam intensity without considering the control rods in the current engineering design stage. In order to get the optimized operation scheme with the stable and reliable features, the variation of beam intensity using the continuous and periodic control approaches has been adopted, and the change of collimator and the adjusting of duty ratio have been proposed in the power control process. Considering the neutronics and the thermal-hydraulics characteristics in CiADS, the physical model for the core power control has been established by means of the point reactor kinetics method and the lumped parameter method. Moreover, the multi-inputs single-output (MISO) logical structure for the power control process has been constructed using proportional integral derivative (PID) controller, and the meta-heuristic algorithm has been employed to obtain the global optimized parameters for the stable running mode without producing large perturbations. Finally, the verification and validation of the control method have been tested based on the reference scenarios in considering the disturbances of spallation neutron source and inlet temperature respectively, where all the numerical results reveal that the optimization method has satisfactory performance in the CiADS core power control scenarios.

• Journal of Environmental Health Sciences
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• v.41 no.2
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• pp.133-145
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• 2015

Objectives: Food safety has become one of the major public-concerning issues in Korea. In order to set guidelines to create manuals for the response to a food safety crisis by food industry, this paper classified food safety crises and suggested techniques to determine crisis level. Methods: This study clarified common terminologies and definitions including in food safety crises. It reviewed various food safety crises and described characteristics, types, and states of crises. Results: The results of this study suggested that a food safety crisis implied a situation in which hazards/risk spreading in the food supply chain was widely described, causing strong public concern followed by a socioeconomic impact, and therefore, requiring the implementation of a prompt and full response regarding the situation. In terms of seeking response plans, food safety crises might be classified according to the penalties resulting from violations of laws and regulations, causative substances, stages of the food supply chain, and first contact point for incidents. The crisis level for a food safety crisis could be classified according to its severity parameters. The guideline matrix was divided into four major stages: Blue/guarded, Yellow/elevated, Orange/high, and Red/severe. This study also suggested several methods for determining the crisis level, such as the simple judgement method, scoring methods using a check-list and a weighted check-list. Conclusion: The severity of related parameters might be of great importance in understanding a crisis and determining response options/challenges for crisis levels.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.2
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• pp.159-168
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• 2020

Current residential electricity rates, which are charged regardless of consumption patterns, have a problem of restricting consumer choice. In order to improve the problem, the Korea government started a demonstration project based on Time-Of-Use(TOU) pricing from September 2019. However, the analysis of its effect is still limited. This study analyzed the changes and limitations of TOU pricing compared to the current progressive pricing. The result showed that the high rate payer's bill decreased by up to 33.8 % while the low rate payer's bill increased by up to 117.7 %. This can lead to the problem of accepting electricity rates from a social point of view. In this study, TOU pricing based on progressive pricing was proposed to overcome the problem. The results presented the rate changes depending on the power consumption patterns while decreasing the average rate change from 32 % to -1.9 %. It means that the proposed pricing can support the TOU effect while maintaining the framework of the existing progressive pricing.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.372-383
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• 2016

This study aimed at analyzing the sensitivity of ozone simulation in accordance with the meteorological nudging for a high nocturnal ozone episode. To demonstrate the effectiveness of nudging methods (e.g., nudging techniques and application domains), the following six experiments were designed: (1) control without nudging, (2) experiment with application of observation nudging to all domains (domain 1~4), and (3)~(6) experiments with application of grid nudging to domain 1, domain 1~2, domain 1~3 and all domains, respectively. As a result, the meteorological nudging had a direct (improvement of input data) and indirect (estimate natural emission) effect on ozone simulation. Nudging effects during the daytime were greater than those during the nighttime due to low accuracy of wind direction during the nighttime. On comparison of the nudging techniques, the experiments in which grid nudging was applied showed more improved results than the experiments in which observation nudging was applied. At this time point, the simulated concentrations were generally similar to the observed concentrations due to the increase in the nudging effect when grid nudging was applied up to the sub-domain. However, for high nocturnal ozone uptakes, the experiment in which grid nudging was applied do domain 1~3 showed better results than the other experiments. This is because, when grid nudging was applied to the high resolution domain (e.g., domain 4 with 1 km), the local characteristics were removed due to the smoothing effects of meteorological conditions.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup1
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• pp.71-78
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• 2016

Printing of pictorial health warnings (PHWs) on cigarette packages became obligatory by the Vietnam Law on Prevention and Control of Tobacco Harm in May 2013. Literature from high-income countries suggests that PHWs motivate smokers to quit smoking although their long-term effects have been questioned due to reduction of impact over time. This study aimed to assess the salience of PHWs and smokers' reactions towards PHWs over time. In May 2014 and May 2015, a cross-sectional questionnaire-based household survey was administered to respectively 1,462 and 1,509 Vietnamese male smokers aged 18 to 35. The result showed that salience of the PHWs 2 years after the implementation was higher than at the point of 1 year after the implementation. The proportion of respondents who tried to avoid noting the PHWs was reduced from 35% in wave 1 to 23% in wave 2. However, "Tried to avoid looking/thinking about the PHWs" increased 1.5 times the odds of presenting quit intention compared to those respondents who did not try to avoid looking/thinking about the PHWs (OR=1.5; 95%CI: 1.2-2.0). In conclusion, avoidance regarding PHWs may not work as a barrier when aiming at a higher level of quit intention. Salience of the PHWs may increase in the period shortly after their introduction onto packs but can be expected to decrease with time. In other words, it might be advisable to change or renew PHWs after a period of implementation to maintain their beneficial effects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.963-970
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• 2015

Laminate structures are used in the automobile, aerospace, and display industries. The advantages of fiber metal laminates are well known. Fiber metal laminates are useful for reducing the weight and improving impact resistance . However, currently, the mechanical properties of fiber metal laminates are not derived. In this paper, we use thickness as a factor for comparing the properties of laminates of various thickness combinations. The properties fiber metal laminates are analyzed using design of experiments. In addition, the finite element method is used to analyze elastic and plastic strains of fiber metal laminates and aluminum plates. The final goal of this paper is to find a suitable finite element model of fiber metal laminates under bending.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.793-800
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• 2008

Recently domestic drinking water industry has recognized membrane-based technology as a promising alternative for water treatment. To ensure successful application of membrane processes, the integrity of membrane systems should be maintained. According to US EPA guidance, the pressure decay test based on the bubble point theory is recommended to detect any membrane defection of which size is close to the smallest diameter of Cryptosporidium oocysts, $3{\mu}m$. Proper implementation of the pressure decay test is greatly affected by initial test pressure, and the interpretation of the test results is associated with upper control limit. This study is conducted to investigate various factors affecting determination of initial test prtessure and upper control limit, including membrane-based parameters such as pore shape correction factor, surface tension and contact angle, and system-based parameters, such as volumetric concentration factor and total volume of system. In this paper, three different hollow fibers were used to perform the pressure decay test. With identical initial test pressure applied, their pressure decay tendency were different from each other. This finding can be explained by the micro-structure disparity of those membranes which is verified by FESEM images of those membranes. More specifically, FESEM images revealed that three hollow fibers have asymmetry, deep finger, shallow finger pore shape, respectively. In addition, sensitivity analysis was conducted on five parameters mentioned above to elucidate their relation to determination of initial test pressure and upper control limit. In case of initial pressure calculation, the pore shape correction factor has the highest value of sensitivity. For upper control limit determination, system factors have greater impact compared to membrane-based parameters.

• Journal of Family Resource Management and Policy Review
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• v.15 no.3
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• pp.131-151
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• 2011

This study attempted to estimate the level of perceived lack of time in Korean society, to link it to time management and to identify the possible association that accounts for time shortage. I employed the gender perspective in order to reveal the dynamics and complexity of the perception of a lack of time in the population. The sample for the study was drawn from the 1999 and 2009 Korean time diary data collected by the Korean National Statistical Office. From the original data, I selected a sample of second shift families(men and women who are presently working and raising children) living in metropolitan areas(including Seoul and six major urban areas in Korea). The dependent variable was time pressure measured by a single-item question on a four-point likert scale. The results of the study showed that working mothers perceived a greater time shortage as compared to working fathers. The time use pattern showed change during the periods, indicating that people worked fewer hours in paid labor and enjoyed more leisure hours and personal care hours. However, on average, people seemed to have experienced a greater time lack in 2009 as compared to 1999. The results from the ordered logistic regression model revealed that even though there were similarities in the impact of relevant factors, men's perception of a lack of time was more closely linked with their work role and social status, while for women, this perception was influenced by work and family duties. This indicates that Korean working mothers and fathers are facing a double jeopardy of time shortage in terms of combining their work and family roles. As a result, the level of time pressure by gender is converging toward a "never enough" phase. These findings generated policy implications and detailed suggestions.

• KIEAE Journal
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• v.17 no.3
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• pp.51-58
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• 2017

Purpose: G-SEED's evaluation of existing buildings in Korea is an important point because the energy consumption and CO2 emissions of existing buildings are continuously increasing due to the aging of buildings over time. In 2016, the government has set up a 'Green Remodeling Certification Standard' in G-SEED in order to revitalize the green remodeling business of existing buildings. As a result, G-SEED is distinguished between buildings with green remodeling and buildings with general remodeling. Therefore, this study analyzed the system of the certification of the green remodeling building which is aimed at improving the performance of the building. Method: First, we analyze characteristics of the existing building certification standards of G-SEED(Korea), LEED(USA), and BREEAM(UK). Second, the evaluation criteria are based on the G-SEED Green Remodeling Certification, 2016, LEED for BD + C: New construction and major renovation v.4, BREEAM UK Non-Domestic Refurbishment and Fit-out 2014. Based on the analysis results, we propose the improvement direction of G-SEED Green Remodeling Certification Standard. Result: Existing buildings should be classified into 'existing building certification' for re-certification and 'green remodeling certification' accompanied by building performance improvement. In addition, building green buildings through performance improvement should include not only energy performance, but also creating a pleasant indoor environment and minimizing environmental impact. Finally, existing buildings have accumulated information on energy and resource use, and a performance improvement plan should be established based on this information.

• Journal of Fashion Business
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• v.11 no.6
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• pp.125-138
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• 2007

The modern fashion contains the religious factors or theories out of numerous cultural traits. Shamanism is a product of the very complicated combination of diversified cultural phenomena and whose traits are depicted as spiritual and artistic forms, reflecting on the materialism culture, social relations, customs, and religious faith. The Shamanism that lies in the life of humans gives much impact on their clothing life up to date, consciously or nonconsciously as well. The Shamanism clothing studied as yet has been focused on the costumes that a Shamanism priest and a shaman, the principal Shamanism performer wears and on the symbolic meaning or formativeness of the traditional shaman clothing that is only confined to certain local regions. The Shamanism in the modern costume influences not only on the traditional clothing unique to shaman but also on the other apparels in a widely extended sense. Nevertheless, the research on the modern costumes related to Shamanism is yet to be progressed. In this context, it is believed that the examination of Shamanism interrelated with a contemporary clothing expression is needed. This work would take a look specifically at how the Shamanism is given in the modern clothing fashion and review the inherent aesthetic characteristics. A fact was driven through this study that the shamanism shown in fashion is not only expressed in the modern style of shaman clothing but also unconsciously absorbed in the fashion on the whole. A finding was also revealed that the geometrical and abstract expression, the implication of animistic components, and the application of inherent shaman's costume on to design in regard to clothing are related to a view point of studying about shamanism. The meaning in each expressive method is focused on the superhumanistic desire of shamanism.