• New & Renewable Energy
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• v.19 no.3
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• pp.1-12
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• 2023

This study aims to evaluate the optimal size of the hydrogen facility to be installed in a zero-energy district in terms of load matching and facility efficiency. A mismatch between energy generation and consumption is a common occurrence in zero-energy districts. This mismatch adversely effects the energy grid. However, using an energy carrier such as hydrogen can solve this problem. To determine the optimal size of hydrogen fuel cells to be used on-site, simulation of hydrogen installation is required at both district-and building- levels. Each case had four operating schedules. Therefore, we evaluated eight scenarios in terms of load matching, heat loss, and facility operational efficiency. The results indicate that district-level installation of hydrogen facilities enables more efficient energy use. Additionally, based on the proposed model, we can calculate the optimal size of the hydrogen facility.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1555-1562
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• 2023

Natural circulation phenomena have been nowadays largely revisited aiming to investigate the performances of passive safety systems in carrying-out heat removal under accidental conditions. For this purpose, assessment studies using CFD (Computational Fluid Dynamics) and also 3D thermal-hydraulic system codes are considered at different levels of the design and safety demonstration issues. However, these tools have not being extensively validated for specific natural circulation flow regimes involving flow mixing, temperature stratification, flow recirculation and instabilities. In the present study, an experimental test case based on a small-scale pool test rig experiment performed by Korea Atomic Energy Research Institute, is considered for code-to-code and code-to-experimental data comparison. The test simulation is carried out using the FLUENT and the 3D thermal-hydraulic system CATHARE-2 codes. The objective is to evaluate and compare their prediction capabilities with respect to the test conditions of the experiment. It was observed that, notwithstanding their numerical and modelling differences, similar agreement results are obtained. Nevertheless, additional investigations efforts are still needed for a better representation of the considered phenomena.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.354-356
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• 2015

As domestic recession has had an adverse impact on many Korean companies in Korea, financial soundness has become a critical issues. It is essential to identify financial risk factors to prevent workout as well as to improve the financial condition of domestic construction companies. Therefore, this study derived important management indicators and the financial ratios that belong to each indicator through a comparative analysis between healthy companies and workout companies with financial statement. As a consequence, key financial ratios are derived into 3 of 25 ratios; Equity Ratio in stability indicator, Total Asset Turnover Ratio in activity indicator, and Labor Equipment Ratio in productivity indicator. So, Korean construction firms are required close monitoring these critical financial ratios indicating variation between construction companies which have opposing statuses in finance in order to keep sound financial condition and increase productivity.

• Coupled systems mechanics
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• v.12 no.6
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• pp.539-555
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• 2023

Although some prediction models have successfully developed for ultra-high performance concrete (UHPC), they do not provide insights and explicit relations between all constituents and its consistency, and compressive strength. In the present study, based on the experimental results, several mathematical models have been evaluated to predict the consistency and the 28-day compressive strength of UHPC. The models used were Linear, Logarithmic, Inverse, Power, Compound, Quadratic, Cubic, Mixed, Sinusoidal and Cosine equations. The applicability and accuracy of these models were investigated using experimental data, which were collected from literature. The comparisons between the models and the experimental results confirm that the majority of models give acceptable prediction with a high accuracy and trivial error rates, except Linear, Mixed, Sinusoidal and Cosine equations. The assessment of the models using numerical methods revealed that the Quadratic and Inverse equations based models provide the highest predictability of the compressive strength at 28 days and consistency, respectively. Hence, they can be used as a reliable tool in mixture design of the UHPC.

• International Journal of Stem Cells
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• v.17 no.2
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• pp.130-140
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• 2024

Cardiac organoids have emerged as invaluable tools for assessing the impact of diverse substances on heart function. This report introduces guidelines for general requirements for manufacturing cardiac organoids and conducting cardiac organoid-based assays, encompassing protocols, analytical methodologies, and ethical considerations. In the quest to employ recently developed three-dimensional cardiac organoid models as substitutes for animal testing, it becomes imperative to establish robust criteria for evaluating organoid quality and conducting toxicity assessments. This guideline addresses this need, catering to regulatory requirements, and describes common standards for organoid quality and toxicity assessment methodologies, commensurate with current technological capabilities. While acknowledging the dynamic nature of technological progress and the potential for future comparative studies, this guideline serves as a foundational framework. It offers a comprehensive approach to standardized cardiac organoid testing, ensuring scientific rigor, reproducibility, and ethical integrity in investigations of cardiotoxicity, particularly through the utilization of human pluripotent stem cell-derived cardiac organoids.

• Ocean and Polar Research
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• v.45 no.4
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• pp.219-228
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• 2023

One reason for the constant change of coastlines is related to natural factors such as waves, tides, changes in ocean currents, and sea level rise, and another reason is with regard to artificial factors such as man-made structures in coastal areas. The recent intensification of climate change is accelerating common efforts around the world to cope with the phenomenon of beach regression. Korea designates Coastal Erosion Management Zones under the 'Coast Management Act' to mitigate its coastal erosion. France, on the other hand, enacted the 2021 Climate Act that promotes adaptation to territory due to beach regression, while gradually limiting development activities at the urban planning level according to the proximity of the coastline through Loi Littoral (The French Coastal Law). This paper reviews the coastal erosion management legislation of both countries, derives implications for legislation in Korea based on an assessment ofFrench legislation, and presents an improvement plan.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.375-381
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• 2013

To assess the risk of marine traffic environments, with high confidential level, the risk factors comprising it should be identified and the risk acceptance criteria should be also provided. Furthermore, the relative importance of each risk factor(the weight of each risk factor on total risk) should be analyzed because the risk is expressed as the sum of risk factors comprising it. The twenty kinds of risk factors and its assessment criteria were suggested for the domestic marine traffic environments by an examination of the existing risk assessment models on the previous studies. The relative importance of each risk factor was also analyzed through the questionnaire using analytic hierarchy process by the marine traffic experts on the same studies. Based on these previous studies, the risk was evaluated at the port of Mokpo and its approaches on this study. The port of Mokpo and its approaches were divided into four sectors for the comparative evaluation, the result of the comparative evaluation on four sectors showed that the risk of the Jeongdeung-hae passage is the highest due to higher risk level of some risk factors(water movements, complexities, tug boats, pilotage, VTS) than the other sectors. The result of this evaluation is in accord with the analysis results of the other studies using various qualitative or quantitative risk analysis methods at the same sea areas.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.261-272
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• 2020

The purpose of this study was to compare the earth science curriculums of South Korea and North Korea. Aspects such as the content of the curriculums and the timing of learning were analyzed, in order to provide basic data that can be used to design a revised and integrated Korean curriculum. The objects of this study were South Korean Science textbooks from grades 5-9, and the high school Unity of Science and Earth Science I and II textbooks. Additionally, from North Korea, the junior middle school Natural Science 1 and 2 textbooks and the senior middle school Chosun Geography 2 and Geography 1 textbooks were analyzed. The results of this study obtained through an analysis that used the Trends in International Mathematics and Science Study (TIMSS 2019) grade 8 earth science assessment framework were as follows. First, South Korea needs to adopt iterative learning. Repetitive learning, which is effective for understanding what is being learned, is applied to only 1 by 8th grade. Second, South Korea needs to adjust the time when certain content is learned. This is because there is a disparity between when content is learned in comparison to North Korea, and the timing of learning of about 50% of the TIMSS standards have not been followed. Third, it is necessary to reflect the content present within the TIMSS that have not been learned. This can be a way to increase the nations' educational competitiveness in the international community. This paper proposed a comparative analysis of South korean and North Korean approaches to the earth science curriculum and conducted practical research to facilitate the construction of an integrated curriculum.

• Journal of Oriental Neuropsychiatry
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• v.26 no.3
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• pp.225-234
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• 2015

Objectives: We aimed to evaluate the use of Korean medicine in patients with dizziness or vertigo, since such study has not been performed previously. Methods: In the current study, we included 3 diagnoses i.e., Disorders of vestibular function (H81), Vertiginous syndromes in diseases classified elsewhere (H82), and Dizziness and giddiness (R42) from the Health Insurance Review and Assessment Service (HIRAS) database for 4 years. We analyzed the database and compared treatment with Korean vs. Western medicine. Results: 1. Korean medical visits and cost have been increasing for 4 years, except 2011. Western medical visits are 11.9 times higher than Korean medical visits. 2. The number of women who received Korean medicine was 2.6 times higher than that of men. 3. Among all ages, the 70~79 years group were the most frequent users of Korean medicine. The older age was correlated with more patients' visits. 4. The comparative number of visits by patient care type for 4 years indicated that outpatients had more visits than hospitalization. Furthermore, outpatient visits have been increasing for 4 years. 5. The comparative number of visits by hospital type for 4 years indicated that visits to the Korean medical clinic were the highest. In primary care, patients used more Korean medicine than Western medicine. In tertiary care, patients used more Western medicine than Korean medicine. 6. Korean medical cost per patient by patient care type for 4 years was a total 89,000 won, hospitalization 449,000 won and outpatient 83,000 won. Costs of all patient care types have been increasing. 7. Korean medical cost per patient by hospital type for 4 years was 156,000 won for Korean medical hospital, 83,000 won for local clinic and 127,000 won for miscellaneous facilities. Costs of all types have been increasing. Conclusions: This study provided objective information about epidemiologic characteristics of Korean medicine in patients with dizziness or vertigo. Furthermore, it provides an understanding of the recent status and forms the basis for further expansion of demand for Korean medicine among patients with dizziness or vertigo.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.11 no.1
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• pp.53-64
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• 2016

Objectives : The aim of this study is to assess the usage of diagnosis codes for somatic dysfunctions and the general characteristics of patients diagnosed with the code, by analyzing health insurance data provided by the Health Insurance Review & Assessment Service(HIRA) of Korea. This investigation is intended to outline future and willing to contribute to further use of diagnosis code and the approach of Oriental Medicine to somatic dysfunction. Materials and Methods : By analyzing HIRA data, those diagnosed with M99 codes, a code attributed to somatic dysfunction, were selected for analysis. Patients included were assessed for the relevant general characteristics, and the specific diagnostic criteria. The current usage rates and noteworthy characteristics of diagnostic codes of somatic dysfunctions were assessed. A comparative analysis between clinical departments and subcategories, and a comparative analysis to data of 2014 was conducted. Results : Patients given M99 codes constituted a small minority of all patients diagnosed in 2011 as shown by HIRA data. The codes were more frequently to older patients, females, outpatients, and those who filed for Health Insurance compensation. Medical institutions participating in the diagnosis were mostly primary care facilities, usually specializing in orthopedic(Western medicine sector) and internal medicine (Oriental Medicine sector). The most registered code in 2011 and 2014 was M995. The same trend can be observed in Oriental/Western medicine institutions and Public health center, on the other hand, between them, have some different patterns both 2nd and 3rd. Conclusions : This investigation is that of current usage of diagnostic codes of somatic dysfunction. HIRA insurance claim data was analyzed. Based on the current results, more precise diagnostic standards of somatic dysfunction are warranted. This study will provide a foundation for future Oriental Medicine approach to somatic dysfunctions.