• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4819-4825
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• 2010

In all of dental ceramics, these materials contained the radio-isotopes with natural abundance ratio. After dental treatment, remained dental ceramics in the oral cavity is caused for human internal dose. In this study, the gross beta activity levels were measured in dental materials including 22 dental ceramics, 1 resin, and 2 cements for estimation of human internal dose. In dental ceramic samples, the obtained results showed that the gross beta activity level varied between 1.317 ~ 2.935 Bq/g and the gross beta activity level was 2.379 Bq/g. And the same level for dentine, opacious dentine, translucent and enamel were 2.479 Bq/g, 2.491 Bq/g, 2.470 Bq/g and 2.069 Bq/g, respectively. The gross beta activity level of temporary resin and cements were negligible, compare to the same level of dental ceramics. The high gross beta activity level observed in opacious dentine code OD-A4 is 2.935 Bq/g thus mainly ascribable to 40K. The reduction of the radiation level of natural radio-isotopes and the improvement of the dental ceramic materials should be required for internal dose reduction.

• Molecular & Cellular Toxicology
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• v.2 no.1
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• pp.29-34
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• 2006

Immunoglobulin E (IgE) plays an important role in the development of allergic disorders including asthma. Cigarette smoking was reported to elevate serum IgE level and air pollutants such as $NO_{2}$ have been reported to modulate the immune system including inflammation. Moreover, genetic polymorphisms of glutathione S-transferases (GSTs) were reported to affect inflammatory diseases including asthma. Therefore, in the present study we tried to investigate whether tobacco smoke or $NO_{2}$ exposure increases the level of IgE and the GST gene polymorphisms are associated with change of IgE level due to tobacco smoke or $NO_{2}$ exposure. We measured urinary cotinine, personal $NO_{2}$ exposure, and serum IgE levels in 300 healthy university students without allergic disorders. Allelic loss of the GSTM1 and GSTT1 and the GSTP1 (lle105Val) polymorphism were determined by PCR and RFLP. Total serum IgE levels were significantly different according to urinary cotinine levels (P=0.046), while $NO_{2}$ passive dosimeter level and genetic polymorphisms of three GSTs were not associated with total IgE level. Moreover, subjects with cotinine $500\;{\mu}g/g$ creatinine or more showed the highest level of total IgE when they had null type of GSTM1, null type of GSTT1, or variant type of GSTP1 (P<0.05). When we considered IgE level according to urinary cotinine levels in strata with the combinations of GSTM1, GSTT1, and GSTP1 genetic polymorphisms, the subjects with GSTM1 null, GSTT1 null, and GSTP1 variant types showed the largest difference between IgE levels of subpopulations according to cotinine levels (P=0.030). However, there was no significant difference between IgE levels of subpopulations according to $NO_{2}$ passive dosimeter levels in any group with combinations of GSTM1, GSTT1, and GSTP1 polymorphisms. This result suggests that smoking increases allergic response measured as IgE level and combinations of the GSTM1, GSTT1, and GSTP1 polymorph isms modify the effect of smoking on serum IgE level.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.235-246
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• 2011

Sea level fluctuations during the Holocene reconstructed by the results of age dating, microfossils researches and sedimentary facies from coastal alluvial plains contain the valuable informations on climatic changes. The sea level during 'maximum phase of transgression' during 6,000~5,000 yr BP was slightly higher than the present by approximately 0.8~1.0 m and the summer temperature conditions seemed to be higher than those of the present by 2~3℃ in the Central Europe when the period of 'Climatic Optimum' might be dominant. The sea level in Korean Peninsula was assumed by 0.8~1.0 m higher at that time compared to the present and climate seemed to be warmer. At 2,000~1,800 yr BP in Korean Peninsula, the sea level reached the higher stand than the present by approximately 1.1~1.3 m and the climatic conditions might be warm similar to the period of 'Climatic Optimum'. Although the temperature in the Central Europe during the period of 'Subboreal' was about 2~3℃ cooler, it is supposed that the sea level in Korean Peninsula was relatively higher than the present. The sea level at 2,300 yr BP might be similar to that of the present, which was the lowest level since the mid-Holocene. From the fact, climatic environment during the cold period might not be reflected exactly in the sea level.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.260-265
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• 2007

This study was carried out to complement water quality standards and to establish new concept for water quality standards reflecting current state of water quality in small streams. By this purpose, discriminant analysis was performed and Water Quality Level Model (WQLM) was developed using the data such as EC, BOD, $COD_{Mn}$, SS, T-N, T-P, $NH_3-N$ in 224 agricultural streams. To give water quality level for water quality parameters, it divided into 20% respectively in the order of excellent water quality. On the basis of the lowest water quality level, water quality level of small streams is granted. As a result of it, number of stream corresponding to Level I was no, Level II was 2 streams, Level III was 22 streams, Level IV was 70 streams, and Level V was 130 streams. Average of water quality in each level was the highest in Level V. EC, SS, and T-N of 7 parameters were selected in variance concerned water quality level. By standardized canonical discriminant function coefficient, EC of three variances was the highest in 0.625 at the discriminant power. The next was T-N (0.509), SS (0.414). By discriminant function for water quality level, Level II was equal to $-2.973+19.376{\times}(EC)+0.647{\times}(T-N)+0.009{\times}(SS)$, Level III was equal to $-3.288+19.190{\times}(EC)+0.733{\times}(T-N)+0.041{\times}(SS)$, Level IV was equal to $-4.462+27.097{\times}(EC)+0.792{\times}(T-N)+0.053{\times}(SS)$, and Level V was equal to $-9.117+40.040{\times}(EC)+1.305{\times}(T-N)+0.111{\times}(SS)$. As a result of test at real agricultural watershed of Jeongan and Euidang in Gongju city, the fitness of WQLM was high to 88.78%. But, to get accomplished water quality assessment more exactly in agricultural streams, we had to concentrate and get vast data, and WQLM was modified and complemented continually.

• Korean Management Science Review
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• v.10 no.1
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• pp.1-22
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• 1993

Systemetic classification of a technology is critical to the development of technology strategy. This paper suggests a new technology classification scheme for computer and communication : a two-level scheme. Technology is first classified by its role and function in the upper level which forms a 2 * 2 matrix. The technology is then further classified into the lower level of 3 classes by associations among technology elements. Thus, a new classification scheme of 2 * 2 * 3 matrix is proposed for the computer and communication technology.

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.358-365
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• 1995

This paper presents another system of multi-level skip-lot sampling plan, which can directly retum to normal inspection from any skpping inspection level when a sudden shift for the worse in the process mean occurs. All the other properties of the proposed sampling plan are similar to those of the Choi's(1993) plan. The formula of the poerating characteristic function for the proposed n-level skip-lot sampling plan is derived. Sone poerating characteristic properties for the proposed plan are graphically compared with those of the Choi's plan.

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.1
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• pp.83-87
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• 1996

This study aims to investigate theoretically and experimentally second-order water level variation. The simple method obtaining second-order water surface elevation and mean water level applicable to both progressive and diffraction wave, mean water level set-down, as well as set-up occurs and it is shown to be in good agreement with the experimental results.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.193-199
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• 1995

This study was designed to investigate the difference of time weighted average(TWA) of noise levels and noise doses by the different operating parameter settings such as exchange rate, threshold level and criterion level for noise dosimeter in the field measurements of noise at industrial working environments. The time weighted averages of noise level and noise doses for noise working environments were determined by noise dosimeter on 80 workers employed at 20 industrial establishments of 8 industries. The results obtained were as follows: 1. The mean time weighted average(TWA) of the noise working environments by the operating parameter settings showed 93.4 dB(A) in 3 dB of exchange rate, 80 dB of threshold level and 90dB of criterion level 92.0 dB(A) in 3 dB-exchange rate, 90 dB-threshold level and 90 dB-criterion level, in 90.8 dB(A) in 5 dB of exchange rate, 80 dB of threshold level and 90 dB of criterion level, and 86.7 dB(A) in 5 dB of exchange rate, 90 dB of threshold level and 90dB of criterion level. 2. ln group of noise level less than 90 dB(A), mean TWAs of 80 dB of threshold level were significantly higher than that of 90 dB of threshold level in 3 dB and 5 dB of exchange rate. 3. The case exceeded threshold limit value of noise was 49(61.3 %) in 3dB, 80dB and 90 dB setting, 44(55.0 %) in 3 dB, 90 dB, 90 dB setting, 33(41.3 %) in 5 dB, 80dB, 90 dB setting and 26(32.5%) in 5 dB, 90 dB, 90 dB setting. Above considerations in mind, it is suggested that exchange rate and threshold level be specified in related laws and regulations in the evaluation of working environments noise.

• Korean Journal of Human Ecology
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• v.5 no.2
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• pp.109-121
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• 1996

The purpose of this study are (1) to examine the reality of contacting with fashion catalogues, (2) to examine the consumer's attitude towards fashion catalogues, (3) to examine the correlation between consumer's attitude towards fathion catalogue by sex and age. It was found that, concerning frequency of contacting with fashion catalogues, women contact with them more frequently than men, and lower ages than higher ages. Also, it was shown that, both man and woman with merchandise catalogues, lower ages with merchant catalogues, and higher ages with mail order catalogues. With regard to methods of contacting with catalogue, it was found that men come to contact mainly through mail, women through the displayed goods in the sales shops, lower ages through the displayed goods in the sales shops and higher ages through mail. Concerning the consumer's attitude towards fashion catalogues, meaningful difference was shown in interesting level, attention level, information offering level and information utilizing level by sex. By age, meaningful difference was shown in interesting level, attention level, information offering level, information reliability level, information utilizing level and purchasing satisfying level. Regarding correlation between consumer's attitude towards fashion catalogues by sex, meaningful correlation was shown between all consumer's attitude. By age, meaningful correlation was not found, between 36 to 45 years old, between information reliability level and interesting level, and attention level, and information offering level, and information utilizing level but meaningful correlation was shown between consumer's other attitude.

• Journal of The Korean Association For Science Education
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• v.23 no.1
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• pp.47-56
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• 2003

The present study was carried out to analyse the frequency(%) for five kinds of inquiry context elements for six kinds of the high school science textbooks in the 7th curriculum. All the elements was classified into three process achievement level such as the basic, supplementary and further level introduced firstly in the 7th curriculum. Five elements of the inquiry context categories appeared as pure scientific context(61.8%), everyday context(22.2%), natural environmental context(7.7%), techno-industrial context(5.9%), and social context(2.4%) in the basic, supplementary and further level. Social context wasn't appeared in the supplementary level. In five elements of inquiry context, total elements appeared 7,139(85.5%) kfrequencies in the basic level and 691(8.1%) frequencies in the further level. However total elements appeared 529(6.4%) frequencies in the supplementary level. The kinds and frequencies of the elements for the inquiry context suggested in the basic level were more than those in the supplementary and in the further level. The social context was not appeared in the supplementary level. However five inquiry context elements were all appeared in the basic and further level.