• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.spc
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• pp.75-87
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• 2020

The Korea Atomic Energy Research Institute (KAERI) has developed geological repository systems for the disposal of high-level wastes and spent nuclear fuels (SNFs) in South Korea. The purpose of the most recently developed system, the improved KAERI Reference Disposal System Plus (KRS⁺), is to dispose of all SNFs in Korea with improved disposal area efficiency. In this paper, a system-level safety assessment model for the KRS⁺ is presented with long-term assessment results. A system-level model is used to evaluate the overall performance of the disposal system rather than simulating a single component. Because a repository site in Korea has yet to be selected, a conceptual model is used to describe the proposed disposal system. Some uncertain parameters are incorporated into the model for the future site selection process. These parameters include options for a fractured pathway in a geosphere, parameters for radionuclide migration, and repository design dimensions. Two types of SNF, PULS7 from a pressurized water reactor and Canada Deuterium Uranium from a heavy water reactor, were selected as a reference inventory considering the future cumulative stock of SNFs in Korea. The highest peak radiological dose to a representative public was estimated to be 8.19×10^-4 mSv·yr^-1, primarily from ¹²⁹I. The proposed KRS⁺ design is expected to have a high safety margin that is on the order of two times lower than the dose limit criterion of 0.1 mSv·yr^-1.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.379-388
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• 2003

The response of single story buildings and other case studies were investigated to observe trends and develop a better understanding of the impact of some design parameters on the seismic response of Concentrically Braced Frames (CBF). While many parameters are known to influence the behavior of braced frames, the focus of this study was mostly on quantifying energy dissipation in compression and its effectiveness on seismic performance. Based on dynamic analyses of single story braced frame and case studies, a bracing member designed with bigger R and larger KL/r was found to result in lower normalized cumulative energy ratio in both cases.

• Journal of Preventive Medicine and Public Health
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• v.53 no.3
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• pp.158-163
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• 2020

Objectives: In the current early phase of the coronavirus disease 2019 (COVID-19) outbreak, Bali needs to prepare to face the escalation of cases, with a particular focus on the readiness of healthcare services. We simulated the future trajectory of the epidemic under current conditions, projected the impact of policy interventions, and analyzed the implications for healthcare capacity. Methods: Our study was based on the first month of publicly accessible data on new confirmed daily cases. A susceptible, exposed, infected, recovered (SEIR) model for COVID-19 was employed to compare the current dynamics of the disease with those predicted under various scenarios. Results: The fitted model for the cumulative number of confirmed cases in Bali indicated an effective reproduction number of 1.4. Interventions have decreased the possible maximum number of cases from 71 125 on day 86 to 22 340 on day 119, and have prolonged the doubling time from about 9 days to 21 days. This corresponds to an approximately 30% reduction in transmissions from cases of mild infections. There will be 2780 available hospital beds, and at the peak (on day 132), the number of severe cases is estimated to be roughly 6105. Of these cases, 1831 will need intensive care unit (ICU) beds, whereas the number of currently available ICU beds is roughly 446. Conclusions: The healthcare system in Bali is in danger of collapse; thus, serious efforts are needed to improve COVID-19 interventions and to prepare the healthcare system in Bali to the greatest extent possible.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.37-48
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• 2018

The extreme 2017 spring drought affected a large portion of central and western South Korea, and was one of the most climatologically driest spring seasons over the 1961-2016 period of record. This drought was characterized by exceptionally low precipitation, with total precipitation from January to June being 50% lower than the mean normal precipitation (1981-2010) over most of western South Korea. In this study, for the quantitative drought impact analysis, the widely-used Standardized Precipitation Index (SPI) and the statistical drought frequency are compared with observed meteorological characteristics and anomalies. According to the drought frequency analysis of monthly cumulative precipitation during January and May in 2017, Gyeonggi-do, Chungcheong-do, and Jeollanam-do areas showed more than drought frequency over 100 years. Gyeongsangnam-do area showed more than drought frequency over 200 years based on annual precipitation in 2017. The South Korean government (Ministry of Agriculture, Food and Rural Affairs (MAFRA) and Korea Rural Community Corporation (KRC)) have been operating a government-level drought monitoring system since 2016. Results from this study can be used to improve the drought monitoring applications of future drought events, as well as drought planning and preparedness in South Korea.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.4
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• pp.228-232
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• 2016

Objective: The aim of this study was to investigate the impact of pretreatment with transdermal estradiol ($E_2$) compared to oral contraceptive pills (OCPs) on controlled ovarian stimulation (COS) response in normal responders undergoing fresh in vitro fertilization (IVF)-embryo transfer (ET) cycles. Methods: A retrospective cohort study was performed of normal responders undergoing fresh IVF-ET cycles who received pretreatment with transdermal $E_2$ versus OCPs prior to fresh IVF-ET. The total days of ovarian stimulation, total dosage of gonadotropins, total number of oocytes, and mature oocytes retrieved were noted. Pregnancy outcomes after ET were also recorded. Results: A total of 2,092 patients met the inclusion criteria: 1,057 and 1,035 patients in the transdermal $E_2$ and OCP groups, respectively. Patients in the OCP group had a longer duration of COS ($10.7{\pm}1.63days$, p< 0.01) than the $E_2$ group ($9.92{\pm}1.94days$). Patients in the OCP group also required higher cumulative doses of gonadotropins ($2,657.3{\pm}1,187.9IU$) than those in the $E_2$ group ($2,550.1{\pm}1,270.2IU$, p= 0.002). No statistically significant differences were found in the total and mature oocytes retrieved or in the rates of biochemical pregnancy, clinical pregnancy, spontaneous miscarriage, and live birth between the groups. Conclusion: Our findings suggest that compared to OCPs, pretreatment with transdermal $E_2$ is associated with a shorter duration of ovarian stimulation and lower gonadotropin utilization, without compromising the oocyte yield or pregnancy outcomes in normal-responder patients undergoing fresh IVF.

• Journal of the Korean Geographical Society
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• v.38 no.6
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• pp.863-886
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• 2003

Internet is the most important element in the emergence of the Internet economy, which derives the creation of new firms and employment, and brings about the new ways of marketing and business. The emergence of the Internet economy and the rapid growth of the Internet industry have a great deal to changes in the spatial economy. Korea has experienced a rapid growth of the Internet industries, but few geographical studies have been done to explain the impact of the development of the Internet industries on the spatial economy. This research explored how Korea has developed as a nation of the strong Internet economy in terms of driving forces by demand and supply side. This research tried to build a data set for the Internet industries with the introduction of a new classification scheme and a measurement. The most important finding from this research was the spatial concentration of the Internet industries toward Seoul at the national level and toward the Gangnam area within Seoul. The rise of Internet industries has added attractiveness to Seoul which enjoys a kind of cumulative and circular advantages.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.827-834
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• 2014

In order to meet the low voltage ride-through requirement in a grid code, a wind power plant (WPP) has to stay connected to a grid, supporting the voltage recovery for a grid fault. To do this, a plant-level controller as well as a wind generator (WG) controller is essential. The dynamic response of a WPP should be analyzed in order to design a plant-level controller. The dynamic response of a WPP for a grid fault is the collective response of all WGs, which depends on the wind speed approaching the WG. Thus, the dynamic response of a WPP should be analyzed by taking the wake effect into consideration, because different wind speeds at WGs will result in different responses of the WPP. This paper analyzes the response of a doubly fed induction generator (DFIG)-based offshore WPP with a grid fault taking into account the wake effect. To obtain the approaching wind speed of a WG in a WPP, we considered the cumulative impact of multiple shadowing and the effect of the wind direction. The voltage, reactive power, and active power at the point of common coupling of a 100 MW DFIG-based offshore WPP were analyzed during and after a grid fault under various wind and fault conditions using an EMTP-RV simulator. The results clearly demonstrate that not considering the wake effect leads to significantly different results, particularly for the reactive power and active power, which could potentially lead to incorrect conclusions and / or control schemes for a WPP.

• Journal of Korean Medical Science
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• v.33 no.50
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• pp.299.1-299.13
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• 2018

Background: Sarcopenia is associated with a poor prognosis in patients with liver cirrhosis. However, it is not known whether the rate of skeletal muscle depletion is also associated with a poor prognosis. We investigated the prognostic impact of the rate of skeletal muscle depletion in patients with liver cirrhosis. Methods: We included retrospectively all patients with liver cirrhosis who underwent both multiple computed tomography scans and hepatic venous pressure gradient (HVPG) measurements. Results: A total of 131 patients with liver cirrhosis were enrolled. The mean age of the patients was 53.7 years and alcoholic liver disease was the most common cause (61.8%). Sixty-four patients (48.9%) were diagnosed with sarcopenia. The median changes in skeletal muscle area per year (${\Delta}SMA/y$) were -0.89%. During a median follow-up period of 46.2 months (range, 3.4-87.6), 45 patients (34.4%) died. In multivariate analyses, age, Child-Pugh score, HVPG, presence of sarcopenia and ${\Delta}SMA/y$ were independently associated with mortality. Cumulative mortality was significantly higher in patients with ${\Delta}SMA/y$ < -2.4% than those with ${\Delta}SMA/y{\geq}-2.4%$ (log-rank test, P < 0.001). Conclusion: Both the presence and rate of change of sarcopenia are independently associated with long-term mortality in patients with liver cirrhosis.

• Structural Engineering and Mechanics
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• v.59 no.1
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• pp.37-57
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• 2016

Reservoir geomechanics can play an important role in hydrocarbon recovery mechanism. In $CO_2$-EOR process, reservoir geomechanics analysis is concerned with the simultaneous study of fluid flow and the mechanical response of the reservoir under $CO_2$ injection. Accurate prediction of geomechanical effects during $CO_2$ injection will assist in modeling the Carbon dioxide recovery process and making a better design of process and production equipment. This paper deals with the implementation of a program (FORTRAN 90 interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators, using a partial coupling algorithm. A geomechanics reservoir partially coupled approach is presented that allows to iteratively take the impact of geomechanics into account in the fluid flow calculations and therefore performs a better prediction of the process. The proposed approach is illustrated on a realistic field case. The reservoir geomechanics coupled models show that in the case of lower maximum bottom hole injection pressure, the cumulative oil production is more than other scenarios. Moreover at the high injection pressures, the production rates will not change with the injection bottom hole pressure variations. Also the FEM analysis of the reservoir showed that at $CO_2$ injection pressure of 11000 Psi the plastic strain has been occurred in the some parts of the reservoir and the related stress path show a critical behavior.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.383-389
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• 2018

Recently, it has been reported that water pollution due to non-point pollutants continues. Studies have been actively carried out to prevent such non-point pollutants from flowing into the water system and to prevent water pollution. In this study, to evaluate the adequate design of the LID facilities the rainfall corresponding to 80% of the cumulative rainfall of Yongin city was applied to an SA / CA graph obtained from the analysis of monitoring results of the vegetation type LID facility. As a result, the appropriate SA/CA ratio was 0.6% for stormwater sustain efficiency 80% and the appropriate SA/CA ratio was 0.5% for TSS removal efficiency 80%. The appropriate SA/CA ratio of the vegetation type LID proposed in this study can be used as a basis. for the future vegetation type LID design. If more data of vegetation type LID are added through continuous research, it will be more accurate.