• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.231-240
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• 2016

The change in chemical compositions of leachate and medium density fiberboard (MDF) from a laboratory-scale simulated landfill which constructed in a plastic container containing alternating layers of soil and MDF was investigated to evaluate decomposing of MDF in soil. Four treatments were conducted: 1) MDF in soil, 2) MDF only, 3) cured UF resin in soil, and 4) soil only. Molecular weight (MW) distribution of compounds in leachate from soil only treatment did not change over time. In UF resin in soil treatment, the MW distribution shifted to a lower MW distribution over time, while the peak shifted to the left indicated changing to higher MW distribution in leachate from treatment 1 and 2 contained MDF. Higher percent nitrogen in leachate was observed in MDF containing treatments due to the UF resin in the MDF. The percent carbon slightly increased in MDF only while that greatly decreased in MDF in soil treatment maybe due to bacterial activity. The percent of extractable materials from the MDF decreased greatly on day 35 compare to day 0, and subsequently did not change much on day 77. In contrast, percent holocellulose and lignin did not change much over time. No structural change of the wood fiber in MDF occurs during the study. Water-soluble materials from MDF in soil contributed the change in chemical composition of leachate.

• Human Ecology Research
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• 제55권5호
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• pp.465-480
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• 2017

This study examined the relationship between family meal time and emotional well-being for 5,186 fathers who were employed and had at least one child aged under 18 for the years 2009 and 2014 by analyzing their time diaries. In doing so, changes in time spent by fathers on family meals between 2009 and 2014 were also examined along with the factors associated with the amount of meal time for each year in order to understand ways to increase paternal participation in family meals. Analytic results showed that a father's family meal time had a positive association with his time use and life satisfaction; however, fathers who spent more than 40 minutes a day having meals with the family reported the highest score in time use and life satisfaction. The amount of time fathers spent on family meals increased from 38 minutes in 2009 to 43 minutes in 2014, whose change turned out to be mainly attributable to something more than the compositional change in the population between the two years, such as growing public awareness or cultural acceptance of the value of family meal. Fathers in dual-earner households tend to have longer family meal times; however, different factors were associated with their family meal times in 2009 and 2014. Policy implications are discussed in light of the government-initiated dining table education campaign to increase family meal time for the sake of children's character education at home.

• Spatial Information Research
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• 제20권4호
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• pp.47-55
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• 2012

Normalized Difference Vegetation Index (NDVI) has been used to measure and monitor plant growth, vegetation cover, and biomass from multispectral satellite data. It is also a valuable index in forest applications, providing forest resource information. In this research, an approach for monitoring forest change using MODIS NDVI time series data is explored. NDVI difference-based approaches for a specific point in time have possible accuracy problems and are lacking in monitoring long-term forest cover change. It means that a multi-time NDVI pattern change needs to be considered. In this study, an efficient methodology to consider long-term NDVI pattern is suggested using a harmonic model. The suggested method reconstructs MODIS NDVI time series data through application of the harmonic model, which corrects missing and erroneous data. Then NDVI pattern is analyzed based on estimated values of the harmonic model. The suggested method was applied to 49 NDVI time series data from Aug. 21, 2009 to Sep. 6, 2011 and its usefulness was shown through an experiment.

• Human Ecology Research
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• 제58권3호
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• pp.447-461
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• 2020

This study explores how the COVID-19 pandemic has changed family life and relationships as well as how these changes affect perceived stress among married men and women. This study investigated changes in family time use, household work, child care, leisure activities, income and expenditures along with relationships between spouses and children using a sample of 627 married persons surveyed online from May 19 to 25, 2020. The results showed that the amount of time spent on household work, child care, and family leisure have increased and that the perceived burden of household work and child care has also increased. Gender differences were found in time use, household work, and child care. Leisure activities have changed toward more time watching TV or online media and playing online games and less time on outdoor activities, shopping, and meeting friends. About 38% of respondents reported a reduction in household income and 22% reported an increase in household debt. The majority experienced no change in the quality of relationships with spouses and children, approximately 20% of the sample reported a positive change in relationships with spouses and children. The findings of multivariate regression indicated that change in work time, negative change in household economy, negative change in household work and negative change in relationships with spouses were associated with marital stress. However, this study found that negative changes in child care and in relationships with children did not affect stress among married parents with children in elementary or secondary school.

• Journal of the Korea Institute of Building Construction
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• 제3권1호
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• pp.115-122
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• 2003

In order to analyze liquidity change according to increasing the charge of superplasticizer, we inputted charges by dividing into six steps, 0% through 1.25%; at the same time, to observe liquidity change according to the change of charge-time, we carried out the experiment applying 30-minute intervals, i.e. at beginning of mixing, 30, 60 and 90 minutes. The results are below. 1) According to increasing the charge of superplasticizer, the liquidity of concrete was enhanced, however, when inputted 1.25%, a little segregation was occurred, which allowed us to make a conclusion that concrete performance would be deteriorated due to this segregation. 2) When we inputted 1.25% of superplsticizer, steady liquidity features were shown regardless of the charge-time of concrete, which allowed us to make a conclusion that this input would be the best for liquidity performance considering only liquidity features. 3) After analyzing the dynamical features of liquid concrete, the result showed that there was not significant effect on revelation of compressive strength. We concluded form this result that there was no influence on the stripping-time of a mold form. 4) When we charge superplasticizer in concrete more than 1%, we, in advance, should clearly judge the concrete performance required during constructing in site, as it were, the compressive strength or liquidity etc.; furthermore, we had better decide a charge and input-time of superplasticizer to meet the required performance.

• Journal of the Korea Safety Management & Science
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• 제18권1호
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• pp.147-152
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• 2016

Chest lateral decubitus is a chest examination to determine the persence of pleural fluid in thorax. In this study, we prepare recumbent holding position time standard of chest lateral decubitus. The records of 15 patients with chest lateral decubitus between May and Jun. Recumbent holding time is 30, 60, 90, 120, 180, 210, 240 seconds. The result is fluid level change between 0.88mm to 9.63. Fluid heigh change between 9.9 percent to 42.5 percent. We can confirm fluid level change with chest decubitus image. The proper time for fluid level change is 180 seconds.

• Journal of the Korean Society of Costume
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• 제42권
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• pp.207-222
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• 1999

This study is a thesis based on the fact that at the end of eighteenth century similar change in hair style appeared in Chosun and France which are located very far almost the opposite side of the earth. We can see that very exaggerated and big hair styles of those days in both countries became exceptionally reduced and changed to practical shapes through (an order prohibiting to make large hair style using wigs) is case of Chosun and through the France Revolution in case of France. Outwardly the abobe mentioned change may seem to be caused by such brave and outward convention as the prohibition order and the revolution. however I think that more basic cause of such change from big and splendid hair styles of those days to simple styles was because of many people's sympathy with the necessity of improving various social and economical problems caused by the luxurious and even prodigal situation of those days before the change and additionally because of such pragmatic thought as Positivism of chosun and illuminism of france. In case of france the change in hair style occurred for such a short period of time around the France Revolution(1789) that we can even that the change occurred in a day. However in case of Chosun such change became fixed at the time of king Suncho prohibiting to make large hair style using wigs (1756-1788) was announced. in case of France such change in hair style was mainly because of change of thought caused by people's self-consciousness. But in case of Chosun under the situation where common people's way of thinking about sumptuous moods and beauty was not changed unvoluntary and compulsory change was asked by the King's order so a lot of time seemed to have been necessary for the change in hair style to become fixed as a nationwide common and general custom.

• Journal of Environmental Science International
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• 제20권11호
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• pp.1425-1435
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• 2011

Time-series change in Gyeongpo beach shoreline was illustrated using DGPS(Differential Global Positioning System, resolution < 0.6m) observation from April, 2009 to April, 2010. The shoreline was subdivided into 12 areas, and westward and eastward movement of shoreline position at each area was calculated. In general, the shoreline moved toward sea during summer, and it moved toward land during winter. The southern and northern part of the shoreline had different pattern in time-series. The shoreline in the southern part moved toward sea during summer and moved toward land during winter, but time-series pattern of the shoreline in the northern part was more complicated than that in the southern part. Pattern of time-series change in the northern part was made up of three different types; the first is that the shoreline moves continuously toward land, and the second thing is that the shoreline's movement is the opposite to the southern part, and the third thing is that the shoreline maintains a state of equilibrium without any great fluctuation. The total length of the shoreline was the largest during winter and the smallest during summer. In general, time-series change in the shoreline had positive(+) relationship with sea surface pressure and wind speed.

• IE interfaces
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• 제23권4호
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• pp.337-348
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• 2010

The Bass model is the most widely used model in research of new product diffusion because it presents a nice explanation on the diffusion process of new products. However, it has a limitation that its performance of fitness is lower as the available data become less and also, the diffusion curve is bell-shape and so, it can not represent the various diffusion patterns. Recently, a two-pieces Bass model is developed and applied to analyze diffusion of 10 products. The results are encouraging in terms of fitness. However, diffusion pattern is not dealt with in the paper. In this paper, analysis of diffusion pattern is in depth addressed in two-pieces Bass model. It is shown that the diffusion curves are divided into 3 types with respect to the peak adoption rate and each type is divided into 2 types further. Takeoff time of a diffusion process is analyzed by using the inflection point and regime-change time where it represents the point that imitation and innovation parameters change. Empirical studies for 68 products(28 domestic products and 40 USA products) are performed to analyze the diffusion pattern. Findings are that diffusion patterns of all products except 1 USA product show type I and regime-change time becomes shorter as the introduction time of the product is later in domestic products and regime-change time can be regarded as a takeoff time in 47% of total 68 products.

• Journal of the Korean Home Economics Association
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• 제29권1호
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• pp.13-25
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• 1991

We measured change of peripheral skin temperature and mean skin temperature when the upper arm and thigh are pressured in order to know the effect of skin pressure applied by clothing on blood circulation. After release from pressure, we observed also recovery condition. At the same time, we examined relation between pressure and a feeling of thightness. Three physiques of healthy females, namely slender, standard and plump, served as subjects. We used continuous restraint method with skin pressure applied by experimental fabric for 10 min. As a result of this experiment, we obtained following findings. 1. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under upper arm restraint. The peripheral and mean skin temperature decreased with the lapse of restraint time. A remarkable tendency observed according to the increase of restraint pressure. Recovery condition after release from pressure not yet recovered to original state, for all after a lapse of 10 min. 2. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under thigh restraint, especially different physique was remarkable among them. The peripheral skin temperature decreased or decreased. Recovery condition after release from pressure was the same upper arm. 3. Main factor affecting the evaluation of a feeling of tightness was restraint pressure. The value of pressure sensation made remarkable declined after a lapse of 10 min restraint time. Individual differences, however, were shown in pressure sensation.