• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.266-278
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• 2012

The objective of this study was developing dynamic stand growth model to predict diameter at breast height (DBH) growth by thinning intensity and cycle for major tree species of South Korea. The yield table, one of static stand growth models, constructed by Korea Forest Service was employed to prepare dynamic stand growth models for 8 tree species. In the process of model development, the thinning type was designated to thinning from below and equations for predicting the DBH change after thinning by different intensities was generated. In addition, stand density (N/ha), age and site index were adopted as explanatory variables for DBH prediction model. Thereafter, using the model, DBH growth under various silvicuture through integrating such equations considering thinning intensities, and cycles. The dynamic stand growth model of DBH developed in this study can provide understanding of effectiveness in forest growth and growing stock when thinning practice is performed in forest. Furthermore, results of this study is also applicable to quantitatively assess the carbon storage sequestration capability.

• Journal of Korean Academy of Nursing
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• v.2 no.1
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• pp.63-72
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• 1971

The conclusions were obtained from the detailed survey of 1,285 students experiencing menstruation, who were chosen among 1,717 students in middle & high school girls in Seoul. The survey was conducted during July 20-July 24, 1971. 1. Age of Menarche An average age of menarche was 13.3$\pm$1.07. The earliest age of menarche was 9 and the latest age 18. Ages of menarche were between 12 and 14 in 84.3 percent of the students surveyed. a. By present age distribution, the aged students were lower, than younger students in the average age of menarche. b. By father′s educational levels, among the students whose fathers were graduated from high schools, college & ever the earliest average age of menarche was found with 13.2, and among the students whose fathers were graduated from primary schools that wag latest with 13.6. c. By father′s occupations, among the students whose fathom engaged in "workers not classifiable"the earliest age of menarche was found with 12.5$\pm$0.27, among the students whose fathers were in "service business"the second was 12.9$\pm$1.07, and among the students whose fathers were in "miners, quarrymen and related workers"that was latest with 13.8$\pm$1.14. d. By economic status, among the students of "wealthy"families the age of menarche was 13.1$\pm$0.25, the among the students of "ordinary"families the lags of menarche 13.3$\pm$1.06. and the among the students of "poor" families that was 13.8$\pm$0.31. e. By home discipline, among the students being treated "rigid" the age of menarche was 13.5$\pm$1.13, among the students being treated "moderate"the age of menarche was 13.3$\pm$0.22, and those being treated "indifferent" that was 13.0$\pm$0.26. f. By students physical condition, among the students of "good" condition the average of menarche was 13.3$\pm$0.16, and among the students "poor" that was 13.5$\pm$0.31. 2. Menstruation a. For the six months after the average of menarche 39.0 percent of the students had normal menstruations, and 61.3 percent of them had abnormal ones. Of the students with abnormal menstruation 21.7 percent had abnormal menstruation from time to time, 25.4 percent had no menstruation for one month to three months, 7.2 percent had menstruation for four to six months and 6.7 per cent had no menstruation for more than sin months. Most students became to have normal menstruations a few months later the age of menarche. b. At the time interviewed, the percentile of cycle of menstruation as following: 23 days types: 46.8 percent 30 days types: 40.6 percent others : 12.6 percent The average cycle of menstruation was every 28.9 days. c. The average duration of menstruation is 4.69 days. d. The subjective symptoms during menstruation period: Out of the total 89.7 per cent had some pains, while 10.3 percent had no symptom. Among the symptoms, abdominal pain occupied 29.9 percent, neurotic symptoms 19.0 percent and lumbago 15.1 percent. e. By attitude or Action at first physical change, "Treated it by own experience" : 30.0 percent "Don′t know what to do because of ignorance" : 20.1 percent "Asked others about it" : 43.0 percent

• Korea journal of population studies
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• v.25 no.2
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• pp.163-192
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• 2002

Residential overcrowding, also called density, measured as more than one person per room, is a important variable as a principal indicator of inadequate housing. We investigated how immigrants in the US are assimilated to the host society through a lens of housing density. We estimated the probability of living in overcrowded housing of Korean, Chinese and Japanese immigrants armored with the 1980 and 1990 Public Use Microdata Sample(PUMS, A, 5%) in the US. Along with economic effects, we also consider life-cycle effects on the indicator. We applied "double cohort" method that enables duration of immigration effects to be separated from aging effects, which captures family size fluctuations due to life-cycle effects. The study found that cohort trends sharply changed during 10years. The 1970's immigrants are more likely to live in overcrowded housing than the pre-1970 immigrants. The pre-1970 immigrants are more likely to live in overcrowded housing than native-born persons. This may be explained by different assimilation processes driven by the disparities of individual human capitals or cultural differences among the ethnic groups. Especially, Korean experienced a sharp decline in overcrowding between 1980 and 1990. We also found that the major determinants that affect the level of housing density are years since migration, income, and gender. The present study concluded with some future studies related to the Korean immigrants abroad.ts abroad.

• Journal of Energy Engineering
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• v.18 no.4
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• pp.230-238
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• 2009

We study about small gas engine and fuel cell CHP (Combined Heat and Power) as the technologies for energy conservation and $CO_2$ emissions reduction. Korea government plans to use them in near future. This study quantitatively analyzed energy consumption and $CO_2$ emissions reduction potential of small CHP instead of existing electric power plant (coal steam, combined cycle and oil steam) using LEAP (Long-range Energy Alternative Planning system) as energy-economic model. Three future scenarios are discussed. In every scenario similar condition for each CHP is used. Alternative scenario I: about 6.34% reduction in $CO_2$ emissions is observed in 2019 due to increase in amount of gas engine CHP and fuel cell CHP while coal use in thermoelectric power plant is almost stagnant. In alternative scenario II: a small 0.8% increase in $CO_2$ emission is observed in 2019 keeping conditions similar to alternative scenario I but using natural gas in combined cycle power plant instead of coal. During alternative scenario II overall $CO_2$ emission reduction is observed in 2019 due to added heat production from CHP. Alternative scenario III: about 0.8% reduction in $CO_2$ emissions is observed in 2019 using similar CHP as AS I and AS II. Here coal and oil are used in thermoelectric power plant but the quantity of oil and coal is almost constant for next decade.

• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.65-77
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• 1982

The intent of this study was to focus attention on the relationship between curtain fabrics and consumer perceptions towards curtains and draperies. This study consisted of the laboratory test for thermal transmittance of selected fabrics and the exploratory survey for consumer perceptions towards curtains and draperies. The objectives of the laboratory test were to measure fabric's thermal transmittance, thickness, and count which affect to the effect in heat controlling. Selected 23 fabrics were tested at Korean Yarn and Fabrics Testing Inspection Institute. The objectives of the exploratory survey were to determine sociodemographic factors; the stage of family life cycle, the economics status, and homemaker's level of education, and physical factors; the type of houses, the direction of windows, and the type of windows, affect consumer perceptions toward curtains and draperies. Questionaires were administered to 489 homemakers selected by a stratified propotional sampling plan, in Seoul in October, 1981. Data from responses were analyzed by T-test(Analysis of Varience) and Partial Correlation. The major findings are as follows; 1. The results of the laboratory test 1) The fabrics used for draperies had higher effect in heat controlling than the fabrics used for glass curtains. 2) It did not show much differences among the fibers in heat controlling. The thicker fibers, however, had the higher effect in heat controlling among same fibers. 3) The fabrics which had high level of effect I heat controlling were corduroy, flax, rayon, nylon, acetate, thick polyester, and thick polyacrylic. The fabrics which had midium level of affect in heat controlling were velveteen, velvet, and thin polyester. The fabrics which had low level of effect in heat controlling were cotton, silk, and thin polyarcylic. 4) The draperies with lining showed 2∼5 times more effective in heat controlling than the draperies without lining. 2. The results of the exploratory survey Consumer perceptions towards curtains and draperies consisted of functional, financial, and aesthetic perception. 1) Factor affecting functional perception towards curtains and draperies was the stage of family life cycle. Families in the contracting stage considered function of curtains and draperies significantly better than those in others stages. 2) Factors affecting financial perception towards curtains and draperies were the economic status, homemaker's level of education, the direction of windows, and the type of windows. However the correlation between the factors and financial perception was too low to explain the significance of tendency. 3) There was not any factors affecting aesthetic perception towards curtains and draperies.

• Korean Journal of Community Nutrition
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• v.10 no.2
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• pp.196-204
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• 2005

Menarche is a main indicator of sexual maturity which relates to a reproductive function. The onset of the menstrual cycle differs individually and is influenced by many variables such as socio-economic situation, race, genetics, climate, altitude, nutritional status, and physical growth. Among them physical growth has been known to be the most influencing factor, particularly when expressed as body fat designated by weight. This study intended to investigate the body composition of girls around the menarche period and to evaluate the minimal levels of weight and fat percentage needed for the onset of menarche. A total of 101 female subjects, aged 11 to 13 years, were recruited from the 5th and 6th grades of an elementary school, in Mokpo, Korea. The subjects were placed into one of two groups Pre-menarche and Post-menarche groups according to their experience with menarche. Thereafter, the subjects in the Post-group were placed into 4 subgroups based on the number of menstruations they experienced: Post-I (1-3 times), Post-II (4-6 times), Post-III (7-9 times), and Post-IV (> 10 times). The average age at the onset of menarche of the subjects in Post groups was $11.2 \pm 0.6$ years. There were significant differences in the data of anthropometry and body composition between the Pre and Post groups, although the mean ages of both Pre and Post groups were the same. Weight, waist, hip and thigh girths, fat percentage, and lean body mass of the Post groups were significantly higher than those of the Pre group. Height was not significantly different between the groups. Weight was highly correlated with body fat mass (r = 0.92. p < 0.001), fat percentage (r = 0.85, p < 0.001), and body mass index (r = 0.91, p < 0.001) These results indicate that weight, compared with height, reflects body composition well and influences the onset of the menstrual cycle. It could also be suggested that the minimal weight and fat percentage needed for the onset of menarche in Korean females are 41 kg and $17\%\;to\;19\%$, respectively.

• Journal of Korea Technology Innovation Society
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• v.11 no.2
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• pp.264-286
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• 2008

In 2006, the share of energy in Korea amounted to 28% from the total import, 97% from overseas dependency, and 83% for the national Greenhouse Gas (GHG) emission in 2004. Thus, from the aspects of economical and environmental policies, an energy analysis is very important, for the industry to cope with the imminent pressure for climate change. However, the estimation of GHG gas emissions due to an energy use is still done in a primitive way, whereby each industry's usage is multiplied by coefficients recommended from international organizations in Korea. At this level, it is impossible to formulate the prevailing logic and policies in face of a new paradigm that seeks to force participation of developing countries through so called post-Kyoto Protocol. In this study, a hybrid energy input-output (E-IO) analysis is conducted on the basis of the input-output(IO) table of 2000 issued by the Bank of Korea in 2003. Furthermore, according to economic sectors, emission of the GHG relative to an energy use is characterized. The analysis is accomplished from four points of view as follows: 1) estimating the GHG emission intensity by 96 sectors, 2) measuring the contribution ratio to GHG emissions by 14 energy sources, 3) calculating the emission factor of 3 GHG compounds, and 4) estimating the total amount of national GHG emission. The total amount estimated in this study is compared with a national official statistical number. The approach could be an appropriate model for the recently spreading concept of a Life Cycle Analysis as it analyzes not only a direct GHG emission from a direct energy use but also an associated emission from an indirect use. We expect this model can provide a form for the basis of a future GHG reduction policy making.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.43-49
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• 2017

In recent years, the use of BIM in domestic construction has been increasing, but it is used mainly for internal and external visualization rather than for BIM design including drawings. For this reason, several studies have highlighted the lack of libraries and economic problems for BIM design. In other words, for the most economically small domestic design offices, activating the BIM design is a negative factor because it is difficult to invest the necessary manpower and cost to produce and use the required BIM library. The BIM design can be more applicable if the library can be supplied economically, easily, and quickly. In this study, BIM library business model and consideration factors that can provide BIM library service economically, easily, and quickly by considering the existing building material selection task and BIM library are presented. The proposed business model will increase the number of suppliers of BIM libraries, which are lacking in Korea, and will enable an effective BIM design at low cost and effort. If a service that reflects the business model proposed in this study is made, an integrated database that can consistently share information in the design, construction, and maintenance stages will be constructed. This can monitor the changes in material and equipment information during the life cycle of the building. The database can be used to monitor any changes in material and equipment information throughout the life cycle of a building, so that it can be used as historical data for effective design and maintenance as well as for material and equipment upgrades.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.549-559
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• 2005

Sustainable industrial development which can minimize an ecological effect by the mankind exertion is recently interested due to an environmental contamination and a resource exhaustion problem. An eco-industrial park (EIP) is a community of manufacturing and service businesses seeking enhanced environmental and economic performance through collaboration in managing environmental and resource issues, including energy, water, and materials. EIP developments which improve a production plant within an eco-friendly greenfield and design a new industrial ecosystem are accomplished recently, which can efficiently re-use the waste and resources from each company within EIP. In this review, the outside and domestic case studies of EIP and cornerstone technologies to develop the EIP, such as energy integration, waste reuse, mass flow analysis, water pinch, and life cycle assessment, are summarized.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.183-193
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• 2020

This study attempts to interpret the causes of offshoring and reshoring, find out facilitating factors and the areas where these happen mainly. In viewpoint of self-organization phenomena, the theory of prospect, quantitative analysis is performed by utilizing actual data of American Reshoring Association. This study shows that offshoring to the U.S. is positively correlated with market power in the U.S. and innovation of investment countries, while reshoring to U.S. is positively correlated with market power in the U.S. not with technology innovation. The reshoring of U.S. companies is influencing offshoring to U.S, emerging countries such as Asia tends to focus offshoring in short catch up cycle area like IT. This study is expected to contribute to investment support policy and decision for optimal production site. Further study will complete the economic benefit assessment model by reinforcing the impact factors of reshoring and offshoring.