• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.115-121
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• 2019

Background: Due to the diversification and advancement of research, researchers have become to deal with a variety of chemical and biological harmful materials in the laboratories of universities and research institutes and the risk has increased as well. Therefore, it is necessary to strengthen the social safety net for laboratory accidents by strengthening the compensation to the level comparable to that of Korean Workers' Compensation & Welfare Service, when the researchers become physically disabled by laboratory accidents. The purpose of this study is to secure researchers' health rights and to create a research environment where researchers can work with confidence by strengthening the compensation to the level comparable to that of Korean Workers' Compensation & Welfare Service. Method: We analyzed the laboratory accidents by year, injury type, severity of accident and disability grade with the 6 year data from 2011 to 2016, provided by Laboratory Safety Insurance. Based on the analysis result, we predicted the financial impact on Laboratory Safety Insurance if we introduce a compensation annuity by disability grade which is similar to Injury-Disease Compensation Annuity of Korean Workers' Compensation & Welfare Service. Result :As of 2011, the insured number of Laboratory Safety Insurance was approximately 700,000. The Average premium per insured was KRW 3,339 and there were 158 claims. Total claim amount was KRW 130 million, whereas the premium was about KRW 2.3 billion. The loss ratio was very low at 5.75%. If we introduce a compensation annuity by disability grade similar to Injury-Disease Compensation Annuity of Korean Workers' Compensation & Welfare Service, the expected benefit amount for 1 case of disability grade 1 would be KRW 1.6 billion, assuming 2% of interest rate. Given current premium, the loss ratio, the ratio of premium income to claim payment, is expected 41.4% in 2017 and 151.6% in 2026. The increased loss ratio due to the introduce of the compensation annuity by disability grade is estimated to be 11.0% in 2017 and 40.4% in 2026. Conclusion: Currently, laboratories can purchase insurance companies' laboratory safety insurance that meets the standards prescribed by Act on the Establishment of Safe Laboratory Environment. However, if a compensation annuity is introduced, it would be difficult for insurance companies to operate the laboratory safety insurance due to financial losses from a large-scale accident. Therefore, it is desirable that one or designated entities operate laboratory safety insurance. We think that it is more desirable for laboratory safety insurance to be operated by a public entity rather than private entities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.279-290
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• 2021

This study evaluated the economic feasibility of facility farms according to the introduction of the ultra-high density pot cultivation (UHDPC) for mango. The basic model was selected as a representative farmhouse case in the Jeonnam region, and seven scenarios for conventional crops were tested. The economic feasibility of crop switching was analyzed through partial budget analysis (PBA). The PBA analysis results were supplemented by adding a sensitivity analysis and a break-even point (BEP) analysis. As a result of the analyses, it was found that crop conversion was economical because the increase in the profit coefficient was greater than the increase in the loss coefficient due to the introduction of mango for all conventional crops. The economics of introducing mango was more sensitive to changes in gross income than to changes in cost items. The results show the detailed conditions of crop selection according to the conditions and preferences of individual farms by presenting the direction of increase and decrease by budget item and information on the amount of increase or decrease. In particular, the BEP analysis result, which is about half of the farms case, is significant in that it presents the minimum target value according to production and market risks.

• Journal of Korean Society of Rural Planning
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• v.27 no.4
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• pp.13-24
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• 2021

This study used big data to analyze visitors' experiences in Fishing Experience Recreation Village. Through the portal site posting data for the past six years, the experience of visiting Fishing Experience Villages in Baekmi and Susan was analyzed. The analysis method used Text mining and Social Network Analysis which are Big data analysis techniques. Data was collected using Textom, and experience keywords were extracted by analyzing the frequency and importance of experience texts. Afterwards, the characteristics of the experience of visiting the Fishing Experience Village were identified through the analysis of the interaction between the experience keywords using 'U cinet 6.0' and 'NetDraw'. First, through TF and TF-IDF values, keywords such as "Gungpyeong Port", "Susan Port", and "Yacht Marina" that refer to the name of the port and the port facilities appeared at the top. This is interpreted as the name of the port has the greatest impact on the recognition of the Fishing Experience Villages, and visitors showed a lot of interest in the port facilities. Second, focusing on the unique elements of port facilities and fishing villages such as "mud flat experience", "fishing village experience", "Gungpyeong port", "Susan port", "yacht marina", and "beach" through the values of degree, closeness, and betweenness centrality interpreted as having an interaction with various experiences. Third, through the CONCOR analysis, it was confirmed that the visitor's experience was focused on the dynamic behavior, the experience program had the greatest influence on the experience of the visitor, and that the experience of the static and the dynamic behavior was relatively balanced. In conclusion, the experience of visitors in the Fishing Experience Villages is most affected by the environment of the fishing village such as the tidal flats and the coast and the fishing village experience program conducted at the fishing port facilities. In particular, it was found that fishing port facilities such as ports and marinas had a high influence on the awareness of the Fishing Experience Villages. Therefore, it is important to actively utilize the scenery and environment unique to fishing villages in order to revitalize the Fishing Experience Villages experience and improve the quality of the visitor experience. This study is significant in that it studied visitors' experiences in fishing village recreation villages using big data and derived the connection between fishing village and fishing village infrastructure in fishing village experience tourism.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4348-4358
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• 2022

The thermal-hydraulics phenomena in a containment during an accident will necessarily include radiative heat transfer (i) within the gas mixture due to the high radiative absorption and emission of steam and (ii) between the gas mixture and the surrounding structures. The analysis of some previous PANDA experiments (PSI, Switzerland) demonstrated the importance of the proper modelling of radiation for the benefit of numerical simulations. These results together with dedicated scoping calculations conducted for the present experiments indicated that the radiative heat transfer is considerable, even for a very low amount of steam (≈2%). The H2P2 series conducted in the large-scale PANDA facility at the Paul-Scherrer-Institut (PSI) in the framework of the OECD/NEA HYMERES-2 project is intended to enhance the understanding of thermal radiation phenomena and to provide a benchmark for corresponding numerical simulations. Thus, the test matrix was tailored around the two opposite extremes: either gas compositions with small steam content such that radiative heat transfer phenomena can be neglected. Or gas mixtures containing larger amounts of steam, so that radiative heat transfer is expected to play a dominant role. The H2P2 series consists of 5 experiments designed to isolate the radiation phenomena from convective and diffusive effects as much as possible. One vessel with a diameter of 4 m and a height of 8 m was preconditioned with different mixtures of air / steam at room and elevated temperatures. This was followed by the build-up of a stable helium stratification at constant pressure in the upper part of the vessel. After that, helium was injected from the top into the vessel which leads to an increase of the vessel pressure and a corresponding elevation-dependent and transient rise of the gas temperature. It is shown that even the addition of small amounts of steam in the initial gas atmosphere considerably impacts the radiative heat transport throughout all phases of the experiments and markedly influences i) the monitored gas peak temperature, ii) the temperature history during the compression and iii) the following relaxation phase after the compression was stopped. These PANDA experiments are the first of its kind conducted in a large scale thermal-hydraulic facility.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4660-4670
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• 2022

Hydroxyurea (HU) is a novel salt-free reductant used potentially for the separation of U/Pu in the advanced PUREX process. In this work, the radiation stability of HU were systematically investigated in solution by examining the effects of the type of rays (α, β, and γ irradiations), the absorbed dose (10-50 kGy), and the HNO₃ concentration (0-3 mol L^-1). The influence degree on HU radiolysis rates followed the order of the absorbed dose > the ray type > the HNO₃ concentration, but the latter two had moderate effects on HU radiolysis products where NH₄⁺ and NO₂^- were found to be the most abundant ones, suggesting that the differences of α, β, and γ rays should be considered in the study of irradiation effects. The radiolysis mechanism was explored using density functional theory (DFT) calculations, and it proposed the dominant radiolysis paths of HU, indicating that the radiolysis of HU was mainly a free radical reaction among ·H, e_aq^-, H₂O, intermediates, and the radiolytic free radical fragments of HU. The results reported here provide valuable insights into the mechanistic understanding of HU radiolysis under α, β, and γ irradiations and reliable data support for the application of HU in the reprocessing of spent fuel.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.294-304
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• 2023

Objective: We aimed to investigate whether image standardization using deep learning-based computed tomography (CT) image conversion would improve the performance of deep learning-based automated hepatic segmentation across various reconstruction methods. Materials and Methods: We collected contrast-enhanced dual-energy CT of the abdomen that was obtained using various reconstruction methods, including filtered back projection, iterative reconstruction, optimum contrast, and monoenergetic images with 40, 60, and 80 keV. A deep learning based image conversion algorithm was developed to standardize the CT images using 142 CT examinations (128 for training and 14 for tuning). A separate set of 43 CT examinations from 42 patients (mean age, 10.1 years) was used as the test data. A commercial software program (MEDIP PRO v2.0.0.0, MEDICALIP Co. Ltd.) based on 2D U-NET was used to create liver segmentation masks with liver volume. The original 80 keV images were used as the ground truth. We used the paired t-test to compare the segmentation performance in the Dice similarity coefficient (DSC) and difference ratio of the liver volume relative to the ground truth volume before and after image standardization. The concordance correlation coefficient (CCC) was used to assess the agreement between the segmented liver volume and ground-truth volume. Results: The original CT images showed variable and poor segmentation performances. The standardized images achieved significantly higher DSCs for liver segmentation than the original images (DSC [original, 5.40%-91.27%] vs. [standardized, 93.16%-96.74%], all P < 0.001). The difference ratio of liver volume also decreased significantly after image conversion (original, 9.84%-91.37% vs. standardized, 1.99%-4.41%). In all protocols, CCCs improved after image conversion (original, -0.006-0.964 vs. standardized, 0.990-0.998). Conclusion: Deep learning-based CT image standardization can improve the performance of automated hepatic segmentation using CT images reconstructed using various methods. Deep learning-based CT image conversion may have the potential to improve the generalizability of the segmentation network.

• Korean Journal of Radiology
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• v.23 no.12
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• pp.1251-1259
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• 2022

Objective: T1 mapping provides valuable information regarding cardiomyopathies. Manual drawing is time consuming and prone to subjective errors. Therefore, this study aimed to test a DL algorithm for the automated measurement of native T1 and extracellular volume (ECV) fractions in cardiac magnetic resonance (CMR) imaging with a temporally separated dataset. Materials and Methods: CMR images obtained for 95 participants (mean age ± standard deviation, 54.5 ± 15.2 years), including 36 left ventricular hypertrophy (12 hypertrophic cardiomyopathy, 12 Fabry disease, and 12 amyloidosis), 32 dilated cardiomyopathy, and 27 healthy volunteers, were included. A commercial deep learning (DL) algorithm based on 2D U-net (Myomics-T1 software, version 1.0.0) was used for the automated analysis of T1 maps. Four radiologists, as study readers, performed manual analysis. The reference standard was the consensus result of the manual analysis by two additional expert readers. The segmentation performance of the DL algorithm and the correlation and agreement between the automated measurement and the reference standard were assessed. Interobserver agreement among the four radiologists was analyzed. Results: DL successfully segmented the myocardium in 99.3% of slices in the native T1 map and 89.8% of slices in the post-T1 map with Dice similarity coefficients of 0.86 ± 0.05 and 0.74 ± 0.17, respectively. Native T1 and ECV showed strong correlation and agreement between DL and the reference: for T1, r = 0.967 (95% confidence interval [CI], 0.951-0.978) and bias of 9.5 msec (95% limits of agreement [LOA], -23.6-42.6 msec); for ECV, r = 0.987 (95% CI, 0.980-0.991) and bias of 0.7% (95% LOA, -2.8%-4.2%) on per-subject basis. Agreements between DL and each of the four radiologists were excellent (intraclass correlation coefficient [ICC] of 0.98-0.99 for both native T1 and ECV), comparable to the pairwise agreement between the radiologists (ICC of 0.97-1.00 and 0.99-1.00 for native T1 and ECV, respectively). Conclusion: The DL algorithm allowed automated T1 and ECV measurements comparable to those of radiologists.

• Imaging Science in Dentistry
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• v.54 no.1
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• pp.81-91
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• 2024

Purpose: The objective of this study was to propose a deep-learning model for the detection of the mandibular canal on dental panoramic radiographs. Materials and Methods: A total of 2,100 panoramic radiographs (PANs) were collected from 3 different machines: RAYSCAN Alpha (n=700, PAN A), OP-100 (n=700, PAN B), and CS8100 (n=700, PAN C). Initially, an oral and maxillofacial radiologist coarsely annotated the mandibular canals. For deep learning analysis, convolutional neural networks (CNNs) utilizing U-Net architecture were employed for automated canal segmentation. Seven independent networks were trained using training sets representing all possible combinations of the 3 groups. These networks were then assessed using a hold-out test dataset. Results: Among the 7 networks evaluated, the network trained with all 3 available groups achieved an average precision of 90.6%, a recall of 87.4%, and a Dice similarity coefficient (DSC) of 88.9%. The 3 networks trained using each of the 3 possible 2-group combinations also demonstrated reliable performance for mandibular canal segmentation, as follows: 1) PAN A and B exhibited a mean DSC of 87.9%, 2) PAN A and C displayed a mean DSC of 87.8%, and 3) PAN B and C demonstrated a mean DSC of 88.4%. Conclusion: This multi-device study indicated that the examined CNN-based deep learning approach can achieve excellent canal segmentation performance, with a DSC exceeding 88%. Furthermore, the study highlighted the importance of considering the characteristics of panoramic radiographs when developing a robust deep-learning network, rather than depending solely on the size of the dataset.

• Journal of Preventive Medicine and Public Health
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• v.27 no.2 s.46
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• pp.337-365
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• 1994

Rubella is a viral disease with mild constitutional symptoms and generalized rashes. In childhood, it is an inconsequential illness, but when it occurs during early pregnant period, there are significant risks of heart defects, cataract, mental retardation to the fetus. The series of congenital defects induced by rubella is called 'congenital rubella syndrome'. Many research have been performed to find out more effective prevention program on rubella. The objectives of this study are, first, to calculate the incidence rate of acute rubella infection and congenital rubella syndrome in Korea, second, to evaluate economic efficiency of several rubella vaccination policies and to offer data for the most reasonable decision on vaccination policy. Study populations are 663,312 children of one year-old in 1992. The author has performed cost-benefit analyses according to the three vaccination policies-U.S.A.'s. U.K.'s and Sweden's. In this Study, the author got the incidence rate of acute rubella infection using the catalytic model. In the meantime, the author used 50 per 100,000 live births as the incidence rate of congenital rubella syndrome. The discount rate used in this study was 5 percent per annum. The sensitivity analyses were done with different discount rates (4%, 7%) and different incidence rate of congenital rubella syndrome (10,100 per 100,000 live births) : The study results are as follows: 1. Without vaccination, lifetime expenditures per patient for acute rubella infeciton amount to 14,822 won and the total expenditures to about 3.1 billion won. Meanwhile, lifetime expenditures per patient for congenital rubella syndrome amount to about 91 million won and the total expenditures to about 16.3 billion won without vaccination. 2. The cost of vaccination for a child of one year old was 2,322 won and the total cost for the one year old children was about 1.5 billion won (American style). The cost for vaccination of female children at fifteen was about 339 million won (Birtish style). And the cost of vaccination at one for both sex and female children at fifteen was about 1.9 billion won (Swedish style). 3. The benefit to cost ratios of vaccination of female children at fifteen that is the british mode of rubella vaccination, was 60.0 at the level of 80% population coverage and 48.6 at 100% coverage. It shows much higher benefit to cost ratio than those of the other two vaccination policies. 4. Both net benefits of vaccination at one (American style) and that of vaccinations at one and fifteen (Swedish style) range from about 17.0 billion to 17.8 billion won, those were larger than that of vaccinations of female children at fifteen (Birtish style, about 16.0 billion). 5. In marginal cost-benefit analysis of only additional program of revaccination, the benefit to cost ratios were 3.6 (80% coverage rate) or 0.6 (100% coverage rate). It implies that additional program was less efficient or inefficient. 6. In sensitivity analysis with different discount rates(4% or 7%) and different incidence rates of congenital rubella syndrome (10 or 100 per 100,000 live births), the benefit to cost ratios has fluctuated in wide range. However, all the ratios of vaccination of female children at fifteen were higher than those of the others. Even under the most conservative assumption, the benefit to cost ratios of all the rubella vaccination policies were higher than 3.3. In conclusion, all the rubella vaccination policies found to be cost-effective and particularly the vaccination of female children at fifteen was strongly recommended.

• The Korean Journal of Air & Space Law and Policy
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• v.22 no.2
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• pp.109-133
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• 2007

The legal labyrinth through which we have just walked is one in which even a highly proficient lawyer could easily become lost. Warsaw Convention's original objective of uniformity of private international aviation liability law has been eroded as the world community ha attempted again to address perceived problems. Efforts to create simplicity and certainty of recovery actually may have created less of both. In any particular case, the issue of which international convention, intercarrier agreement or national law to apply will likely be inconsistent with other decisions. The law has evolved faster for some nations, and slower for others. Under the Warsaw Convention of 1929, strict liability is imposed on the air carrier for damage, loss, or destruction of cargo, luggage, or goods sustained either: (1) during carriage in air, which is comprised of the period during which cargo is 'in charge of the carrier (a) within an aerodrome, (b) on board the aircraft, or (c) in any place if the aircraft lands outside an aerodrome; or (2) as a result of delay. By 2007, 151 nations had ratified the original Warsaw Convention, 136 nations had ratified the Hague Protocol, 84 had ratified the Guadalajara Protocol, and 53 nations had ratified Montreal Protocol No.4, all of which have entered into force. In November 2003, the Montreal Convention of 1999 entered into force. Several airlines have embraced the Montreal Agreement or the IATA Intercarrier Agreements. Only seven nations had ratified the moribund Guatemala City Protocol. Meanwhile, the highly influential U.S. Second Circuit has rendered an opinion that no treaty on the subject was in force at all unless both affected nations had ratified the identical convention, leaving some cases to fall between the cracks into the arena of common law. Moreover, in the United States, a surface transportation movement prior or subsequent to the air movement may, depending upon the facts, be subject to Warsaw, or to common law. At present, International private air law regime can be described as a "situation of utter chaos" in which "even legal advisers and judges are confused." The net result of this barnacle-like layering of international and domestic rules, standards, agreements, and criteria in the elimination of legal simplicity and the substitution in its stead of complexity and commercial uncertainty, which manifestly can not inure to the efficient and economical flow of world trade. All this makes a strong case for universal ratification of the Montreal Convention, which will supersede the Warsaw Convention and its various reformulations. Now that the Montreal Convention has entered into force, the insurance community may press the airlines to embrace it, which in turn may encourage the world's governments to ratify it. Under the Montreal Convention, the common law defence is available to the carrier even when it was not the sole cause of the loss or damage, again making way for the application of comparative fault principle. Hopefully, the recent entry into force of the Montreal Convention of 1999 will re-establish the international legal uniformity the Warsaw Convention of 1929 sought to achieve, though far a transitional period at least, the courts of different nations will be applying different legal regimes.