• Korean Journal of Hydrosciences
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• v.5
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• pp.45-55
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• 1994

A new method to estimate the mean areal precipitation using kriging is developed. Urlike the conventional approach, points for double and quadruple numerical integrations in the kriging equation are selected randomly, given the boundary of area of interest. This feature eliminates the conventional approach's necessity of dividing the area into subareas and calculating the center of each subarea, which in turn makes the developed method more powerful in the case of complex boundaries. The algorithm to select random points within an arbitrary boundary, based on the theory of complex variables, is described. The results of Monte Carlo simulation showed that the error associated with estimation using randomly selected points is inversely proportional to the square root of the number of sampling points.

• Journal of Forest and Environmental Science
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• v.25 no.3
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• pp.167-175
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• 2009

An exploratory study was conducted in Juri Forest Range-2, a proposed biodiversity conservation area of Bangladesh to explore the present growing stock of tree, regeneration condition and status of non-timber forest products (NTFPs). This conservation area contains both natural and artificial plantation was selected by using multistage random sampling method. For determination of plot size and sampling methods, the quadrate size ($10m{\times}10m$) for tree stock measurement, ($2m{\times}2m$) for regeneration survey, ($20m{\times}20m$) for NTFPs survey was determined. Regarding tree stock survey, 14 species under eight families were found where Tectona grandis shows average number of stem/ha was 624 and basal area/ha was (10.36 $m^2/ha$) followed by Acacia auriculiformis (0.2 $m^2/ha$ and 637 stem/ha), Gmelina arborea (0.2 $m^2/ha$ and 600 stem/ha). In regeneration survey, 14 species were found belonging to 9 families where Alstonia scholaris shows highest (3,750) seedling per hectare. Regarding NTFPs, bamboo and cane are the most common resources. In last ten years, the total timber output was 1,28,596.14 cubic feet and total amount of revenue was 4,64,434 US$. The vacant area is 1,335.5 acre which contains 14% of total area. If this vacant area is planted with suitable species and take proper steps for appropriate management of this species it will be a good biologically diversified area.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.719-728
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• 2004

The aims of this study were to estimate genetic parameters for carcass traits on Hanwoo(Korean Native Cattle) and to compare two different statistical algorithms for estimating genetic parameters. Data obtained from 1526 steers at Hanwoo Improvement Center and Hanwoo Improvement Complex Area from 1996 to 2001 were used for the analyses. The carcass traits considered in these studies were carcass weight, dressing percent, eye muscle area, backfat thickness, and marbling score. Estimated genetic parameters using EM-REML algorithm were compared to those by Bayesian inference via Gibbs Sampling to find out statistical properties. The estimated heritabilities of carcass traits by REML method were 0.28, 0.25, 0.35, 0.39 and 0.51, respectively and those by Gibbs Sampling method were 0.29, 0.25, 0.40, 0.42 and 0.54, respectively. This estimates were not significantly different, even though the estimated heritabilities by Gibbs Sampling method were higher than ones by REML method. Since the estimated statistics by REML method and Gibbs Sampling method were not significantly different in this study, it is inferred that both mothods could be efficiently applied for the analysis of carcass traits of cattle. However, further studies are demanded to define an optimal statistical method for handling large scale performance data.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.228-237
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• 2005

To compare the occurrence of Coleoptera by different sampling methods such as light trap, pitfall trap and sweeping, we collected samples every month from April to September,2004 in the Mt. Yeonyeop, Gangwon-do, Korea. According to the sampling methods, the species composition, abundance and dry weight were completely different. We collected 151 species in 35 families (690 individuals) by sweeping method, 148 species in 30 families (689 individuals) by light trap, and 112 species in 18 families (1,674 individuals) by pitfall trap, respectively. The dry weight in collected sample was about 181.46 g in pitfall trap,39.85 g in light trap, and 10.89 g in sweeping method, respectively. Relatively high flight and small-sized beetles such as Coccinellidae, Nitidulidae, Scarabaeidae were collected in light trap. The species diversity was high in July. Unlike the samples collected in light trap, the pitfall trap samples were big-sized saprophagous or carnivorous beetles such as Carabidae, Silphidae, Staphylinidae. The pitfall trap showed relatively the higher number of individual and lower species diversity compared to other methods. The major samples collected by sweeping method were small-sized carnivorous or herbivorous beetles such as Chrysomelidae, Curculionidae, Coccinellidae. The peak of species diversity occurred in May. The similarity was calculated with the Jaccard's index over the light trap-pitfall trap was 0.07, light trap-sweeping was 0.10, and pitfall trap-sweeping was 0.01. Consequently, similarity of sampling methods was relatively low. In conclusion, efficiency of the each sampling methods significantly differed in the species composition of Coleoptera. This study emphasize the necessity of using three sampling methods in the area of diversity research.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.287-294
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• 2004

Pits and mounds created by windthrow have significant impacts on forest ecosystem. In order to establish initial data base, 80 pits and mounds were sampled and surveyed in 5 fir forests in Nae-Sorak Mountain. Characteristics and forms were surveyed and frequency of tree species appearance were surveyed as well. 4.9％ of surveyed area (0.4 ha) was pits and mounds in El and E2 areas except old areas where survey was done by estimation. E3 area showed the highest proportion, 11.7％ of 0.1 ha of sampling area.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.885-893
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• 2013

This paper considers Bayes estimations of the small area means under Fay-Herriot model with measurement errors. We provide empirical Bayes predictors of small area means with the corresponding jackknifed mean squared prediction errors. Also we obtain hierarchical Bayes predictors and the corresponding posterior standard deviations using Gibbs sampling. Numerical studies are provided to illustrate our methods and compare their eciencies.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1175-1182
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• 2021

The receiver of each radio telescope of KVN, has a sampler that converts astronomical radio signal to digital data. The ability of this sampler (the bandwidth, sampling frequency, and sampling bits) is improved by sqrt(n), if the bandwidth is increased by n times, and the number of observable objects increases exponentially in the case of continum spectrum radio sources. As the bandwidth increases, there are the more spectrum lines that can be simultaneously monitored in the radio source. This will greatly expand the research area in astronomical radio observation. For this reason, we are trying to independently develop the technology of the fast digital sampler. Therefore, based on the research experience and technology accumulated so far, An ability of sampling up to 3.5 GHz, that can vary the sampling frequency and can observe in a wider band, was designed and made for proto-type. In this study, we introduce the development details and test results for new sampling system.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.2
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• pp.161-170
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• 2002

Total(=wet+dry) atmospheric depositions were collected by filtration-sampling method at 17 sampling sites of the coal-fired power plant area from September 1999 to January 2000. The soluble and insoluble fractions of deposition were also measured to investigate a suitability of simplified collection method for a long-term monitoring of total deposition. In the study, the 50% of sampled soluble fractions showed the electric conductivity (E.C.) of below 50 $\mu$S/cm and the 42% of them showed the lower pH than 5.0. The monthly mean fluxes of water soluble ionic components; S $O_4$$^{2-}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , N $a^{+}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$ were 168.4 kg/k $m^2$.month, 100.5 kg/k $m^2$.month, 88.6kg/k $m^2$.month, 31.3kg/k $m^2$.month, 25.6 kg/k $m^2$.month, 13.3 kg/k $m^2$.month, 8.7 kg/k $m^2$.month, 43.1kg/k $m^2$.month, respectively. The mean ionic concentration of all sample(n=79) was 314 $\mu$eq/ι, with contributions of 24.2% and 23.0% by [nss-C $a^{2+}$] and [nss-S $O_4$$^{2-}$]. The ratio of [N $O_3$$^{[-10]}$ ]/[nss-S $O_4$$^{2-}$] and [N $H_4$-C $a^{2+}$] were found to be 0.52 and 0.68, respectively.espectively.

• Journal of Environmental Science International
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• v.13 no.12
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• pp.1079-1088
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• 2004

In order to understand chemical characteristics and dewfall formation in western Busan area, we analysed monthly distribution of dewfall, and investigated the correlation between dewfall formation amount and meteoro­logical factors. This study used the modified teflon plate $(1m{\times}1m)$ at Silla university in Busan from August 2002 to April 2003. In order to estimate qualitatively water soluble components, IC, ICP and UV methods for water soluble ions are also used respectively. Dewfall amount of sampling periods (47 day) collected 3.8 mm. Meteorological conditions for the formation of dewfall above $50\;g/m^{2}$ showed that temperature diurnal $range(^{\circ}C)\;was\;5.6^{\circ}C$ above, cloud amounts (1/10) at dawn of the sampling day was 7/10 below, mean wind speed at dawn (0~6hr) of the sampling day was 4.4 m/sec below, and mixing ratio at 6hr of the sampling day was 3.2 g/kg above. Distribution of water soluble ions in dewfall founded the highest concentration (206.1\;{\mu}eq/{\ell}\;for\;SO_{4}^{2-},\;42.4\;{\mu}eq/{\ell}\;for\;NH_{4}^{+},\;249.2\;{\mu}eq/{\ell}\;for\;Ca^{2+},\;and\;42.0\;{\mu}eq/{\ell}\;for\;Mg^{2+})$ during the March, the lowest concentration $(73.0\;{\mu}eq/{\ell}\;for\;SO_{4}^{2-},\;4.6\;{\mu}eq/{\ell}\;for\;NH_{4}^+\;and\;72.7\;{\mu}eq/{\ell}\;for\;Ca^{2+})$ during the August. Monthly equivalent ratio of $[SO_{4}^{2-}]/[NO_{3}^-]$ showed the highest value (4.99) during the October, the lowest value (1.84) during the August, and the mean value was 3.45.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.331-336
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• 1999

A great deal of attention has been given in recent years to large diameter specimen for evaluation of soft soil characteristics, and many studies and developments of the apparatus for obtaining large diameter undisturbed soil samples are in progress attempting to minimize the disturbance of samples for precise strength and consolidation tests in the laboratory. This paper introduces a new large diameter sampler(over 300mm diameter), which can take prefectly undisturbed sampling at any depths applying a new sampling technique. By comparing the results of consolidation tests it is shown that the samples obtained by this new apparatus are of a superior quality to that of samples obtained by conventional sampler(Nx, 75mm dia.) at the same depths.