• Journal of Radiation Protection and Research
• /
• v.46 no.3
• /
• pp.98-105
• /
• 2021

Background: In recent events of the coronavirus disease 2019 (COVID-19) pandemic, computed tomography (CT) scans are being globally used as a complement to the reverse-transcription polymerase chain reaction (RT-PCR) tests. It will be important to be aware of major organ dose levels, which are more relevant quantity to derive potential long-term adverse effect, for Korean pediatric and adult patients undergoing CT for COVID-19. Materials and Methods: We calculated organ dose conversion coefficients for Korean pediatric and adult CT patients directly from Korean pediatric and adult computational phantoms combined with Monte Carlo radiation transport techniques. We then estimated major organ doses delivered to the Korean child and adult patients undergoing CT for COVID-19 combining the dose conversion coefficients and the international survey data. We also compared our Korean dose conversion coefficients with those from Caucasian reference pediatric and adult phantoms. Results and Discussion: Based on the dose conversion coefficients we established in this study and the international survey data of COVID-19-related CT scans, we found that Korean 7-year-old child and adult males may receive about 4-32 mGy and 3-21 mGy of lung dose, respectively. We learned that the lung dose conversion coefficient for the Korean child phantom was up to 1.5-fold greater than that for the Korean adult phantom. We also found no substantial difference in dose conversion coefficients between Korean and Caucasian phantoms. Conclusion: We estimated radiation dose delivered to the Korean child and adult phantoms undergoing COVID-19-related CT examinations. The dose conversion coefficients derived for different CT scan types can be also used universally for other dosimetry studies concerning Korean CT scans. We also confirmed that the Caucasian-based CT organ dose calculation tools may be used for the Korean population with reasonable accuracy.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.1 s.113
• /
• pp.27-33
• /
• 2006

Newsprint is quantitatively the most important printing paper. The demands for its printability are continuously increasing. It is well known that the relationship between the physically tested paper properties and newspaper printability is unsatisfactory. In order to improve the printing quality of Korean newsprint, the printability coefficients such as maximum ink requirement(Ymax), print through were investigated. Kinds of newspapers and black printing ink were tested by IGT printability tester. Experiment condition of IGT printability tester was 14 steps between $0.2{\sim}2.8g/m^2$ of ink requirement, printing pressure was 200 N and printing velocity was 1 m/sec. The properties of newspaper samples (basis weight, bulk density, roughness, smoothness, porosity, i. e.) were examined in accordance with KS and TAPPI standard testing methods. The result of this study are respected for usefulness printing quality management of Korean newsprint.

• Journal of the Korean Regional Science Association
• /
• v.15 no.3
• /
• pp.1-13
• /
• 1999

Since the 1990's, the most important environmental issue on the earth is characterized by "global worming problem". The United Nations Framework Convention on Climate Change (UNFCCC) plays an significant role to solve this problem on a worldwide scale. The main purpose of this paper is to analyse the impact of $CO_2$ reduction on the Daegu regional economy through 1995 regional input-output coefficients derived from the 1995 national input coefficients table by using non-survey method. The sectoral impacts on output, income, and employment were computed under the decline-unequalized assumption in final demand influenced by $CO_2$ reduction. This article has six main sections. Section 1 is an introduction to this paper. Section 2 explains briefly the derivation method of the regional technical coefficients. Section 3 describes the model building through input-output multipliers. In section 4 regional data on output, income, employment and final demand are computed to estimate the regional impacts. Section 5 deals with impact analysis on the Daegu economy. Section 6 contains a brief summary and concludintg remarks. The research findings of this study can be summarized as follows. In 1995, under the assumption of 10% decrease on an average in final demand sectors, the economy of the region studied decreased \3600 billion of output, ￦1114 billion of income, and 49919 man-years of employment. The percent ratios of each value to the total showed 9.4%, 9.7%, and 9.2%, respectively. The dominant sectors associated with impact analysis within the region are chemicals and chemical products, paper, printing and publishing, and textiles and leather, etc; nevertheless, the least dominant sector is non-metallic mineral products. products.

• Journal of Korean Association for Spatial Structures
• /
• v.20 no.1
• /
• pp.49-59
• /
• 2020

This study investigates the wind pressure characteristics of elliptical plan retractable dome roof. Wind tunnel experiments were performed on spherical dome roofs with varying wall height-span ratios (0.1~0.5) and opening ratios (0%, 10%, 30% and 50%), similar to previous studies of cirular dome roofs. In previous study, wind pressure coefficients for open dome roofs have been proposed since there are no wind load criteria for open roofs. However, in the case of Eeliptical plan retractable dome roof, the wind pressure coefficient may be largely different due to the presence of the longitudinal direction and transverse direction. The analysis results leads to the exceeding of maximum and minimum wind pressure coefficients KBC2016 code.

• Journal of the Korean Regional Science Association
• /
• v.8 no.2
• /
• pp.11-26
• /
• 1992

In spite of her abundant natural resources for tourist industry, Kangreung and Sokcho area became lagged in economic development during the national industrialization. The major purpose of this study is to exactly purpose of this study is to exactly measure the impacts of tourist industry on regional development. Through the regional input-output analysis, we found some critical facts: (1) Input coefficients are relatively high in those industries as fish products, food and drink products, and printing and publishing. (2) Input coefficients are high in fiber and apparel products, and other manufac-turing. (3) Induced production effects are high in chemical and coal products, fish products, food and fish products, printing and publishing, and public administration for Sokcho. (4) As for the induced employment effect, food and lodging, other services, wholesale and retail show high coefficients. (5) As for the location quotients, food and lodging, fish products, transportation and ware housing are identified as basic industries. Through the questionnaire survey, we also found some important facts: (1) Residents tend to evaluate employment effects higher than the income effects from resort-related development. (2) Pollution, forest demolition, general price increase, and traffic congestions are more serious than ever reported. (3) Willingness to participate in resort development is high, but is discouraged by the lack of regional capital. Based on these findings, we suggest some future directions of tourist industry: (1) blocking the leakage of income produced in tourist and tourist industry, (2) connection between fishery and tourist industry, (3) development of tourist route, and (4) administrative reshuffling that helps joint development between private and public sectors.

• Journal of Korea Water Resources Association
• /
• v.31 no.3
• /
• pp.235-242
• /
• 1998

The objective of this study is to develope a predictive model for flood forecasting in the tidal reaches of the Nakdong river and to analyze the tidal effects of major flood forecasting station of the Nakdong river by using the hydraulic flood routing. In the calibration process the optimum roughness coefficients as functions of channel reach and discharge were determined and the calibration results suggest that the unsteady hydraulic flood routing model simulated with the optimum roughness coefficients showed close agreement between the calculated and observed stage.

• JOURNAL OF ELECTRICAL WORLD
• /
• no.9 s.81
• /
• pp.12-20
• /
• 1983

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.1
• /
• pp.68-73
• /
• 2010

The aim of the present study was to determine the changes in mineral retention of broiler chicks fed diets based on wheat, sorghum or maize during the first two weeks post-hatch. The retention of five major minerals (calcium, phosphorus, potassium, sodium and magnesium) and four trace minerals (iron, manganese, zinc and copper) was determined on days 3, 5, 7, 9 and 14 of age. The retention coefficients of individual minerals differed widely and the retention coefficients of major minerals were found to be considerably higher than those of trace minerals. Age effects were significant (p<0.05) for all minerals. In general, mineral retention coefficients were highest at day 3, declined to day 7, and remained unchanged to day 14. Decline in mineral retention with age was similar on all three diets. The cereal effect was significant (p<0.05) for several minerals, with a general tendency for the sorghum-based diet to have greater retention than maize- or wheat-based diets.

• Journal of Families and Better Life
• /
• v.10 no.1 s.19
• /
• pp.1-13
• /
• 1992

The purpose of this study was to validate the Elementary HOME(Home Observation for Measurement of the Environment) with korean elementary children. Subjects were 536 mothers 1st-5th graders in the elementary schools in the Seoul. Pearson's r, pearcentage(%), phi($\phi$/), Cronbach's $\alpha$/ ware conducted for the statistical analysis. The major findings were as follows. 1) The item pass rate(percentage) were ranged 16~98. 2) The discriminant coefficients($\phi$/) of the item were ranged 0.06~0.58. 3) The reliability coefficients of the scale were that the split-falf was 0.84, and Cronbach's $\alpha$/ was 0.88. Considering the length of the scale, these reliability estimates appear to be at an acceptable level 4) The factor analysis and the correlations between HOME and SES indices and children's school schievement to test construct validity were conducted to test construct validity. Eight factors were extracted from the factor analysis and coefficients(r) were ranged 0.16~0.45 and -0.08~0.37.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.12
• /
• pp.1686-1689
• /
• 2002

Genetic gains and inbreeding coefficients in a Holstein MOET breeding population were predicted under different conditions relating to the distribution of the number of transferable embryos collected per flush using Monte Carlo simulation. The numbers of transferable embryos collected per flush were determined using five distributions (distributions 1, 3, 5, 7 and 9) with different aspects and similar means. Distributions 1, 3, 5, 7 and 9 were assumed to have gamma distribution's parameters ($\alpha$ and $\beta$) of (1 and 4.4), (3 and 1.47), (5 and 0.88), (7 and 0.63) and (9 and 0.49), respectively. Inbreeding rates were statistically significantly different among distributions but genetic gains were not. Relationships between inbreeding rates and variances of family size could be were clearly distinguished. The highest inbreeding coefficients were predicted in distribution 1 with the largest variance of family size, while distributions 5, 7 and 9 with smaller variance of family size had lower inbreeding coefficients.