• Communications for Statistical Applications and Methods
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• v.8 no.2
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• pp.407-416
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• 2001

Sample surveys are usually designed and analyzed to produce estimates for a large area or populations. Therefore, for the small area estimations, sample sizes are often not large enough to give adequate precision. Several small area estimation methods were proposed in recent years concerning with sample sizes. Here, we will compare simple Bayesian approach with Bayesian prediction for small area estimation based on linear regression model. The performance of the proposed method was evaluated through unemployment population data form Economic Active Population(EAP) Survey.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.223-232
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• 2002

For the zoning of natural ecosystem, Vegetation Index is calculated from the vegetation data surveyed on Baekdudaegan (Pijae-Doraegijae). Five factors -biodiversity, conservation value of the stand, environmental quality, longevity of the stand, site productivity- are considered in the calculation of Vegetation Index. Vegetation Index might be a useful zoning tool for management of Baekdudaegan. For Vegetation Index I, 59 sample plots 52.2% of total 113 sample plots are belong to core area, 34 sample plots 30.l% and 20 sample plots 17.7% are belong to buffer zone and transition area, respectively. For Vegetation Index II, 49 sample plots 43.4% of total 113 sample plots are belong to core area, 38 sample plots 33.6% and 26 sample plots 23.0％ are belong to buffer zone and transition area, respectively.

• Korean Journal of Environment and Ecology
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• v.18 no.2
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• pp.158-166
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• 2004

For the zoning of natural ecosystem, Vegetation Index is calculated from the vegetation data surveyed on Baekdudaegan (from Namdeogyusan to Sosagogae). Five factors-biodiversity, conservation value of the stand, environmental quality, longevity of the stand, site productivity- are considered in the calculation of Vegetation Index. Vegetation Index might be a useful zoning tool for management of Baekdudaegan. For Vegetation Index I, 8 sample plots 12.l％ of total 66 sample plots are belong to core area, 21 sample plots 31.8％ and 37 sample plots 56.l％ are belong to buffer zone and transition area, respectively. For Vegetation Index II, 37 sample plots 41.9% of total 60 sample plots are belong to core area, 19 sample plots 28.8％ and 19 sample plots 28.8% are belong to buffer zone and transition area, respectively.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.59-65
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• 1992

Pollen analysis to clear vegetational history of korea was carried out on the deposite taken from the pit of the miruksa site, south-western korea(36o00'18'N, 127o1'12'E, 10m in alt.). This area has been known as the cool temperate zone(southern zone) according to yim and kira(1975). But, now we can not found the original vegetation because the area has been disturbed severely and almost area changed to cultivated land.the area is one of the most developd area in early agricultural stage of korea. By the pollen diagram, three local pollen zones are distinguished in this site, bottom to surface, as following. is-Ⅰ :pinus-quercus zone (140∼120 cm, sample 1 and 2) is-Ⅱ :ulmus+zelkova zone(120∼84 cm, sample 3∼6) is-Ⅲ :pinus zone(84∼0 cm, sample 7 ∼13) is-Ⅰ is characterized by high values in frequences of pinus, the temperate conifer and quercus the cool temperate oak, and is-Ⅱ zone by the decrease of quercus and increase of ulmus and increase of ulman+zelkova as ravine forest elements, isⅢ zone is characterized by pinus, especially, based on data of sample no.9.

• Journal of the Korean Statistical Society
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• v.14 no.2
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• pp.100-117
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• 1985

This paper describes an outline of the sampling design for crop area survey and product survey in Korea. The design attempts to from a double statification, to obtain an efficient allocation of the sample and to reduce the sampling error by establishign crop concentrated strata. The optimum numbers of sample field and sample plot are investigated. The design is made it possible to reduce the sampling errors as well as to reduce the sample size further than the present survey.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.330-330
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• 2022

In recent studies, cold plasma has been used to induce exudation of polyphenols and flavonoids from food materials, leading to enhancement of functional properties. And it is known that polyphenols interact with inflammation related metabolism. The objectives of this study were to investigate the effects of cold plasma treatments on the increase of total phenolic content (TPC), total flavonoid content (TFC), and anti-inflammatory activities of 'Sinpalkwang' peanut (Arachis hypogaea L.) hull. Plasma treatments were carried out using a dielectric barrier discharge gas exchange system at different radicals and temperatures (O₃-25℃, O₃-150℃, NO_x-150℃). Significant differences in TPC, TFC, and inflammatory mediator such as nitric oxide (NO) and tumor necrosis factor a (TNF-α) in lipopolysaccharide stimulated Raw 264.7 macrophages were observed between treated and non-treated peanut hull samples (p < 0.001). Cold plasma treated samples showed higher content (TPC: 2.87-2.93 mg/g sample, TFC: 0.96-0.98 mg/g sample) than non-treated sample (TPC: 2.47 mg/g sample, TFC: 0.78 mg/g sample). Cold plasma treated samples showed lower content of NO (3.3-5.0 uM) and TNF-α (141.4-162.2 ng/mL) than non-treated sample (NO: 11.1 uM, TNF-α: 210.2 ng/mL). This study suggests that cold plasma has potential to improve functionalities of food materials and that cold plasma treated peanut hull can be used as immune enhancing materials.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.4
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• pp.4242-4250
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• 1976

The determination of the pre-consolidation load known to have a great effect on the consolidation characteristics of the soil have been researched and discussed in detail by many other researchers. A study was undertaken to investigate and compare the effect of pre-consolidation loads on the coefficient of permeability and the consolidation characterisics of soil through the consolidation test on the three types of soil samples. The results of this study are follows; 1. Large compression index is dependent on initial void ratio of the sample being used and the pressure-void ratio curve shows a curved linear relationship in over-consolidated area but a linear relationship in normally consolidated area.2. Settlement-time curve is S-shaped where the pressure is larger than pre-consolidation load and regardless of over-burden pressure, it is a similar straight line respectively in the secondary consolidation area. 3. Primary consolidation ratio of the sample increases almost linearly with the increase of over-burden pressure but the coefficient of volume compressibility decreases linearly with the increase of it. 4. Time factor of a certain degree of consolidation increases with over-burden pressure but the coefficient of consolidation decreases with it in over-consolidated area. There is a linear relationship between them in normally consolidated area. 5. The void ratio of completion point of primary consolidation decreases linearly with over-burden pressure. 6. The coefficient of permeability of sample decreases linearly with over-burden pressure in normally consolidated area, also it increases linearly with increment of the void ratio of the sample.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1129-1138
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• 2011

Small area estimation has received significant intention in recent years due to a growing demand for reliable local area statistics. Traditional area-specific direct estimates based solely on sample survey data in the areas of interest do not provide adequate small area precision; however, design-based indirect local area estimators borrow strength from sample observations of related areas to increase the effective sample size. Design-based indirect estimation methods such as synthetic and composite estimators are considered to adjust local area unemployment rate estimates in the Korean Economically Active Population Survey. This study suggests an efficient alternative to minimize the cost to construct the unemployment rate of a local area through simulation under the condition that we can maintain a certain level of CV for the estimates. We obtained the results that the composite estimators using a sample size greater than 10 are more stable and significant at the level of CV 25% in our design scheme.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.145-159
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• 1996

We propose an adaptive searching method using some spatial relations among sample points to estimate the interesting area in the spatial population. The fundamental idea is to observe the neighboring sample points when a sample point is satified with some condition of an adaptive searching observation. For obseving the sample points with this method to estimate the area the sample size is decreased. From this result, we may expect to reduce the cost and time consuming in observation the sample points and to draw the shape of the interesting area without prior information of an spatial population. Some analytical simulation results are also presented.

• Transactions of Materials Processing
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• v.31 no.3
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• pp.136-142
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• 2022

The purpose of this study was to investigate the effects of sample thickness and support structure on the residual stress of Hastelloy X superalloy samples fabricated by laser powder bed fusion (LPBF), which is an additive manufacturing process. The residual stresses of LPBF samples with different thicknesses and support structures were measured using X-ray diffraction. The results revealed that as the thickness of sample increased from 2.5 mm to 20 mm, its tensile residual stress gradually decreased from 443.5 MPa to 182.2 MPa. Additionally, the residual stress in the bottom region of sample was higher than that in the top region, and the residual stress difference in the bottom and top regions became more pronounced as the sample thickness decreased. The residual stress of LPBF sample also varied depending on the structure of support. The residual stress of sample decreased with increasing contract area between the sample and the support, because the larger contract area led to smaller temperature gradient throughout the sample.