• Journal of Preventive Medicine and Public Health
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• v.36 no.4
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• pp.349-358
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• 2003

Objectives : Aseptic meningitis is a major cause of Korean childhood morbidity late spring and early summer. However, the nationwide incidences of the disease have not been reported. This study was conducted to evaluate the availability of National Health Insurance data (NHID) for the study of an epidemiological trend in the surveillance of aseptic meningitis in children. Methods : All the claims, under A87, A87.8, and A87.9 by ICD-10, among children below 15 years of age, to the National Health Insurance Corporation, between January and December 1998, were extracted. A survey of the medical record of 3,874 cases from 136 general hospitals was peformed. The availability of the NHID was evaluated by the three following methods: 1) The diagnostic accuracy (the positive Predictive value : proportion of the confirmed aseptic meningitis among the subjects registered as above disease-codes in NHID) was evaluated through a chart review, and according to age, gender, month and region of disease-occurrence. 2) The distribution of confirmed cases was compared with the distribution of total subjects from the NHID, for subjects in General hospitals, or the subjects surveyed. 3) The proportion of confirmed CSF test was confirmed, and the relating factor, which was the difference in CSF-test rate, analyzed. Results : Among 3,874 cases, CSF examinations were peformed on 1,845 (47.6%), and the CSF-test rates were different according to the medical utility (admission vs. OPD visit) and the severity of the symptoms and signs. The diagnostic accuracy for aseptic meningitis, and during the epidemic (May-Aug) and sporadic (Sept-Apr) periods, were 85.0 (1,568/1,845), 86.0 (1,239/l,440) and 81.2% (329/405), respectively. The distributions by age, sex, month or period (epidemic/sporadic) and region, in the confirmed cases, were similar to those in the NHID, in both the subjects at General hospitals and in those surveyed, to within ${\pm}7%$. Conclusions : In this paper, the NHID for the subjects registered with an aseptic meningitis disease-code might be available for an epidemiological study on the incidence-estimation of childhood aseptic meningitis, as the NHID could include both the probable and definite cases. On the basis of this result, further studies of time-series and secular trend analyses, using the NHID, will be peformed.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.57-65
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• 2007

Over the past few decades, considerable numbers of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in both measuring techniques as well as modeling of ionic flows. However, the majority of these researches have been performed on sound uncracked concrete, although most of in-situ concrete structures have more or less micro-cracks. It is only recent approach that the attention has shifted towards the influence of cracks and crack width on the penetration of chloride into concrete. The penetration of chlorides into concrete through the cracks can make a significant harmful effect on reinforcement corrosion. On the other hand, a general acceptable crack width of 0.3 mm has been recognized for keeping the serviceability of concrete structures in accordance with a lot of codes. However, there seems to be rare established description to explain the critical crack width in terms of the durability of concrete. To make a bad situation worse, there is little agreement on critical crack width among a few of literatures for this issue. Critical crack width is still controversial problem. Nevertheless, since the critical crack width is important key for healthy assessment of concrete structures exposed to marine environment, it should be established. The objective of this study is to define a critical crack width. The critical crack width in this study is designed for a threshold crack width, which contributes to the first variation of chloride diffusion coefficient in responsive to the existence of cracks. A simple solution is formulated to realize the quantifiable parameter, chloride diffusion coefficient for only cracked zone excluding sound concrete. From the examination on the trend of chloride diffusion coefficient of only cracked zone for various crack widths, a critical crack width is founded out.

• Earthquakes and Structures
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• v.15 no.6
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• pp.667-685
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• 2018

In eccentrically braced steel frames (EBFs), the links are fuse members which enter inelastic phase before other structure members and dissipate the seismic energy. Based on the force-based seismic design method, damages and plastic deformations are limited to the links, and the main structure members are required tremendous sizes to ensure elastic with limited or no damage. Force-based seismic design method is very common and is found in most design codes, it is unable to determine the inelastic response of the structure and the damages of the members. Nowadays, methods of seismic design are emphasizing more on performance-based seismic design concept to have a more realistic assessment of the inelastic response of the structure. Links use ordinary steel Q345 (the nominal yielding strength $f_y{\geq}345MPa$) while other members use high strength steel (Q460 $f_y{\geq}460MPa$ or Q690 $f_y{\geq}690MPa$) in eccentrically braced frames with high strength steel combination (HSS-EBFs). The application of high strength steels brings out many advantages, including higher safety ensured by higher strength in elastic state, better economy which results from the smaller member size and structural weight as well as the corresponding welding work, and most importantly, the application of high strength steel in seismic fortification zone, which is helpful to popularize the extensive use of high strength steel. In order to comparison seismic behavior between HSS-EBFs and ordinary EBFs, on the basis of experimental study, four structures with 5, 10, 15 and 20 stories were designed by PBSD method for HSS-EBFs and ordinary EBFs. Nonlinear static and dynamic analysis is applied to all designs. The loading capacity, lateral stiffness, ductility and story drifts and failure mode under rare earthquake of the designs are compared. Analyses results indicated that HSS-EBFs have similar loading capacity with ordinary EBFs while the lateral stiffness and ductility of HSS-EBFs is lower than that of EBFs. HSS-EBFs and ordinary EBFs designed by PBSD method have the similar failure mode and story drift distribution under rare earthquake, the steel weight of HSS-EBFs is 10%-15% lower than ordinary EBFs resulting in good economic efficiency.

• Journal of Preventive Medicine and Public Health
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• v.42 no.4
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• pp.251-260
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• 2009

Objectives : To estimate the annual socioeconomic costs of stroke in Korea in 2005 from a societal perspective. Methods : We identified those 20 years or older who had at least one national health insurance (NHI) claims record with a primary or a secondary diagnosis of stroke (ICD-10 codes: I60-I69, G45) in 2005. Direct medical costs of the stroke were measured from the NHI claims records. Direct non-medical costs were estimated as transportation costs incurred when visiting the hospitals. Indirect costs were defined as patients and caregivers productivity loss associated with office visits or hospitalization. Also, the costs of productivity loss due to premature death from stroke were calculated. Results : A total of 882,143 stroke patients were identified with prevalence for treatment of stroke at 2.44%. The total cost for the treatment of stroke in the nation was estimated to be 3,737 billion Korean won (KRW) which included direct costs at 1,130 billion KRW and indirect costs at 2,606 billion KRW. The per-capita cost of stroke was 3 million KRW for men and 2 million KRW for women. The total national spending for hemorrhagic and ischemic stroke was 1,323 billion KRW and 1,553 billion KRW, respectively, which together consisted of 77.0% of the total cost for stroke. Costs per patient for hemorrhagic and ischemic stroke were estimated at 6 million KRW and 2 million KRW, respectively. Conclusions : Stroke is a leading public health problem in Korea in terms of the economic burden. The indirect costs were identified as the largest component of the overall cost.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.617-626
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• 2019

This study analyzes the optimal location of gas detectors through the gas dispersion in a cargo compressor room of a 174K LNG carrier equipped with high-pressure cargo handling equipment; in addition, we propose a reasonable method for determining the safety regulations specified in the new International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC). To conduct an LNG gas dispersion simulation in the cargo compressor room-equipped with an ME-GI engine-of a 174 K LNG carrier, the geometry of the room as well as the equipment and piping, are designed using the same 3D size at a 1-to-1 scale. Scenarios for a gas leak were examined under high pressure of 305 bar and low pressure of 1 bar. The pinhole sizes for high pressure are 4.5, 5.0, and 5.6mm, and for low pressure are 100 and 140 mm. The results demonstrate that the cargo compressor room will not pose a serious risk with respect to the flammable gas concentration as verified by a ventilation assessment for a 5.6 mm pinhole for a high-pressure leak under gas rupture conditions, and a low-pressure leak of 100 and 140 mm with different pinhole sizes. However, it was confirmed that the actual location of the gas detection sensors in a cargo compressor room, according to the new IGC code, should be moved to other points, and an analysis of the virtual monitor points through a computational fluid dynamics (CFD) simulation.

• Clean Technology
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• v.26 no.3
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• pp.228-236
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• 2020

Korea has an economy based on manufacturing industrial fields, which produce high amounts of hazardous wastes, in spite of few landfill candidates, and a significant concern for fine airborne particulates; therefore, traditional waste management is difficult to apply in this country. Moreover, waste collection and accumulation have recently been intensified by the waste import prohibitions or regulations in developing nations, the universalization of delivery services in Korea, and the global COVID-19 crisis. This study thus presents a domestic waste management strategy that aims to address the recent issues on waste. The contents of the strategy as the main results of the study include the (1) improvement of the compatibility of the classification codes between the domestic hazardous waste and the international ones such as those of the Basel Convention; (2) consideration of the mixed hazard indices to represent toxicity from low-content components such as rare earth metals often contained in electrical and electronic equipment waste; (3) management application based on risks throughout the life cycles of waste; (4) establishment of detailed material flow information of waste by integrating the Albaro system, Pollutant Release and Transfer Register (PRTR) system, and online trade databases; (5) real-time monitoring and prediction of the waste movement or discharge using positional sensors and geographic information systems, among others; and (6) selection and implementation of optimal treatment or recycling practices through Life Cycle Assessment (LCA) and clean technologies.

• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.134-148
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• 2023

Background: The conducting of health effect surveys (HESs) in environmentally contaminated vulnerable areas (ECVAs) by the central and local governments has been increasing apace with the increase in demand for HESs since the Environmental Health Act was enacted in South Korea in 2008. Objectives: This study aimed to review the HESs of residents in ECVAs conducted in South Korea. Methods: An analysis was performed on 125 reports obtained from the Environment Digital Library, PRISM, and local government websites after selecting from 803 projects obtained as ECVAs from the Korea ON-Line E-Procurement System (1997~2021), National Institute Environment Research (2000~2021), and Korea Environmental Industry and Technology Institute (2009~2021). The reports were classified by background (residents' demand, HES, and more), research design (cross-sectional study, cohort, ecological study, and panel), pollution source (abandoned metal mine (AMM), industrial complex (IC), and more), and assessment method of exposure and health effects. The survey area was converted into administrative district codes for geographical mapping. Results: There were 37, 34, 18, and 10 cases associated with AMM, IC, waste incinerators, and coal-fired power plants, respectively. Most of the studies conducted were cross-sectional studies and ecological studies. The proportion of epidemiological investigations by residents' demand showed an increase from 0.0% to 8.9% for the central government while decreasing from 16.7% to 14.3% for local governments after 2008 compared to before 2008. HESs increased at both the central and local government levels since 2014. For the evaluation method, 365 environmental hazards, 319 health outcomes, and 302 biological markers were investigated, with the most commonly investigated items being metals, cancer, and blood metals. Conclusions: HESs of residents in ECVAs in South Korea have been continuously developed both quantitatively and qualitatively. Future improvements are expected, and systematic review and classification of the HESs is warranted.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.202-207
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• 2012

The radioactivity inventory significantly affects all steps of decommissioning projects including planning, cost estimation, risk assessment, waste management and site remediation. The decommissioning project of the KRR-2 was completed in 2009 and a large amount of activated concrete waste was generated. The bioshield concrete, containing minute amount of impurity elements, was activated by neutron reaction during the operation of the reactor. A variety radionuclides was generated in the concrete, including $^3H$, $^{14}C$, $^{55}Fe$, $^{60}Co$ $^{63}Ni$, $^{134}Cs$, $^{152}Eu$ and $^{154}Eu$. In this paper, the comparison between the calculated results and previous measured results was carried out to estimate the inventory of the bioshield concrete of the KRR-2. The combined computer codes of MCNP5 and ORIGEN 2.1 for calculation of the distribution of neutron flux, cross-section and generation of radionuclides were used. The results were shown that 99.8% of the total radioactivity of $^3H$, $^{55}Fe$, $^{60}Co$ and $^{152}Eu$ in the bioshield concrete 12 years after shutdown. The effects on the variation of inventory were analysed depending on the operation periods and the cooling times in the bioshield concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.9-20
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• 2014

Steel intermediate moment frames (IMFs) have been generally used as seismic load resisting systems (SLRSs) of a building to provide resistances against strong ground shaking. However, most of low and mid-rise steel buildings in Korea were constructed during pre-seismic code era or before the introduction of well-organized current seismic codes. It has been recognized that the seismic performance of these steel IMFs is still questionable. In order to respond to such a question, this study quantitatively investigates the seismic capacities of steel IMFs. Prototype models are built according to the number of stories, the levels of elastic seismic design base shear and the ductilities of structural components. Also, the other prototype models employing hysteretic energy dissipating devices (HEDDs) are considered. The collapse mechanism and the seismic performance of the prototype models are then described based on the results obtained from nonlinear-static and incremental-dynamic analyses. The seismic performance of the prototype models is assessed from collapse margin ratio (CMR) and collapse probability. From the assessment, the prototype model representing new steel IMFs has enough seismic capacities while, the prototype models representing existing steel IMFs provide higher collapse probabilities. From the analytic results of the prototype models retrofitted with HEDDs, the HEDDs enhance the seismic performance and collapse capacity of the existing steel IMFs. This is due to the energy dissipating capacity of the HEDDs and the redistribution of plastic hinges.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.2
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• pp.100-104
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• 1994

The rock matrix diffusion provides a retarding mechanism for sorbing and especially non-sorbing radionuclides. It has to be verified not only theoretically and experimentally but also from natural phenomena, before the mechanism can be incorporated fully into transport codes. The natural analogue studies, such as the concentration variation of radionuclides in profiles perpendicular to fluid-conducting fractures and to intrusive contact zones, have been believed to provide a validation. In thermal alteration zones of Naeduckri granite intruded by a pegmatite, large alkali and alkaline earth elements such as K, Rb, Sr, and Ba were moderately migrated during thermal alteration. Li, V. and Nb were also migrated about 9cm in width from the contact between the granite and the pegmatite. The concentration variation of these elements in thermally altered zones seems to be resulted from the local migration due to the re-equilibration among the elements released from the breakdown of primary minerals in the granite. Most of these natural analogue studies simply show only the concentration variation of elements without detailed informations on the diffusion time and other important data fir interpreting the behaviour of radionuclides, because of the absence of appropriate minerals for age data. Despite this problem, natural analogue studies will be needed for transport models of radionuclides in safety assessment.