• The Korean Journal of Applied Statistics
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• v.29 no.3
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• pp.463-470
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• 2016

In analysing a time series on the frequency domain, the spectral estimator (or periodogram) is a very useful statistic to identify the periods of a time series. However, the spectral estimator is very sensitive in nature to outliers, so that the spectral estimator in terms of M-estimation has been studied by some researchers. Pak (2001) proposed an empirical method to choose a tuning parameter for the Huber's M-estimating function. In this article, we try to implement Pak's estimation proposal in the spectral estimator. We use the Korean housing price index as an example data set for comparing various M-estimating results.

• Journal of Food Hygiene and Safety
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• v.1 no.2
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• pp.171-176
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• 1986

ABSTRACT-In order to detect the aflatoxins in home-made Takju and peanut butter, the samples were collected in Chungbuk region and cleaned up Sep-pak silica cartridge. Aflatoxins were detected by thin layer chromatographic and high performance liquid chromatographic behavior. Determination was carried out by thin layer densitometer. The results were as follows; 1. Aflatoxin B, was detected in 78% of the home-made Takju, and the highest concentration was 1.2 ppb and average 0.36 ppb. 2. Aflatoxins were not detected in any peanut butter smaples. 3. Clean-up method by Sep-pak silica cartridge was more efficient and economical than column chromatography of AOAC method.method.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.342-351
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• 2019

The optimum N concentrations incorporated as pre-planting nutrient charge fertilizer were determined for seedling raising using cylindrical paper pots. A root medium was formulated by blending of peat moss (particles smaller than 2.84 mm were 80-90%) and perlite (1 to 3 mm) with the ratio of 7:3 (v/v). The treatment N concentrations incorporated during the root medium formulation were adjusted to 0, 150, 250, 500, and $750mg{\cdot}L^{-1}$ and the concentrations of essential nutrients except N were equal in all treatments. After making of paper pots and putting into the 40-cell tray, the seeds of Chinese cabbage ('Chunmyeong Bom Baechu') and pak-choi ('Hanog cheonggyeongchae') were sown. During the raising of seedlings, weekly analysis of medium pH, EC and concentrations of inorganic elements were conducted. After 21 and 20 days after seed sowing of Chinese cabbage and pak-choi, the growth of the above-ground parts were measured and contents of inorganic elements in the plant tissues were analyzed. During the growing period, pH of the root media rose gradually and the EC decreased rapidly at week 3. The pH of root media at harvest was in the range of 5.3 to 5.9 in Chinese cabbage and 4.93 to 5.39 in pak-choi. Growth of the aboveground parts in terms of fresh and dry weight in both the plants were the highest in the $250mg{\cdot}L^{-1}$ N treatment and the lowest in the control treatment. The elevation of pre-planting N concentrations in root medium resulted in the increase of tissue N content and decrease of P, Ca, and Mg contents. The regression equation derived from the influence of varied pre-planting N concentrations on dry weight of above-ground tissue were $y=-0.0036x^2+0.0021x+0.0635$ ($R^2=0.9826$) in Chinese cabbage and $y=-0.16x^2+0.0009x+0.032$ ($R^2=0.991$) in pak-choi. When the low critical concentration of pre-plant N is taken at the point where dry weight of above-ground tissue is 10% less than maximum (0.40 g in Chinese cabbage and 0.16 g in pak-choi), those point are 0.36 g and 0.144 g per plant in Chinese cabbage and pak-choi, respectively. The lower critical N concentrations of root media calculated from the regression equations are $196mg{\cdot}L^{-1}$ for Chinese cabbage and $187mg{\cdot}L^{-1}$ for pak-choi. These results indicate that optimum pre-plant N concentrations for seedling raising using paper pots are in the range of 196 to $250mg{\cdot}L^{-1}$ for Chinese cabbage and 187 to $250mg{\cdot}L^{-1}$ for pak-choi.

• Korean Journal of Plant Taxonomy
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• v.47 no.1
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• pp.23-26
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• 2017

We reported an unrecorded plant species, Galium bungei var. miltorrhizum (Hance) Jeong & Pak in Korea. This species is found in Gyeonggi-do, Chungcheongbuk-do, Jeollabuk-do, Gyeongsangbuk-do, and Gyeongsangnam-do. G. bungei var. miltorrhizum is distinguished from related taxa by glabrous stem and glabrous or rarely short papillate mericarps. This taxon was named 'Dung-geun-ne-ip-gal-kwi' in Korean based on shapes of leaves. We provided a description, illustrations, photographs, and a key of related taxa in Korea. And we propose a new combination (Galium bungei var. miltorrhizum).

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.135-144
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• 2003

In this paper, the implementation techniques of intelligent nuclear material surveillance system based on the SOM(Self Organized Mapping) was described. Unattended continuous surveillance systems for nuclear facility result in large amounts of data, which require much time and effort to inspect. Therefore, it is necessary to develop system that automatically pinpoints and diagnoses the anomalies from data. In this regards, this paper presents a novel concept of a continuous surveillance system that integrates visual image and radiation data by the use of neural networks based on self-organized feature mapping

• Communications for Statistical Applications and Methods
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• v.25 no.1
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• pp.99-107
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• 2018

This article considers a robust Kalman filter from the M-estimation point of view. Pak (Journal of the Korean Statistical Society, 27, 507-514, 1998) proposed a particular M-estimating function which has the data-based shaping constants. The Kalman filter with the proposed M-estimating function is considered. The structure and the estimating algorithm of the Kalman filter accompanying the M-estimating function are mentioned. Kalman filter estimates by the proposed M-estimating function are shown to be well behaved even when data are contaminated.

• Bulletin of the Korean Mathematical Society
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• v.30 no.1
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• pp.17-23
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• 1993

In this paper, we will discuss on the above problem for the case that .upsilon. is a Riemannian foliation. If .upsilon. is a Riemannian foliation on (M, g), we derive some basic relations between the curvature $R^{D}$ of the normal connection D and the curvature R of the Levi-Civita connection .del. on (M, g) (see Lemma 1).).

• The monthly packaging world
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• s.100
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• pp.194-197
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• 2001

• Kyungpook Mathematical Journal
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• v.21 no.1
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• pp.91-115
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• 1981

• Journal of the Korean Mathematical Society
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• v.6 no.1
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• pp.23-31
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• 1969