• International Journal of Highway Engineering
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• v.12 no.2
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• pp.115-121
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• 2010

To evaluate the engineering characteristics of aggregate base materials, cyclic triaxial, CBR and permeability tests were performed for 15 samples. The CBR values of aggregate base materials have wide range from 32 to 110(average 81) and the amount of swelling in submerged conditions has below 0.04mm. The Modulus of aggregate base materials were significantly affected by volumetric stress, linear volumetric model was best for fitting. The modulus of aggregate base materials were determined within range of 100MPa~600MPa, 80~270 and 0.1~0.6 for model coefficient $k_1$ and $k_2$ respectively. The empirical correlation model was suggested that prediction the modulus from the basic properties obtained from particle size distribution test and compaction test. The coefficient of determination of the proposed correlation model was 0.423 for model coefficient $k_1$, 0.920 for model coefficient $k_2$ and 0.872 for modulus with stress level.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.348-356
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• 2009

The objective of this paper is to estimate the DMT utility function for the transportation mode choice using SP survey. With the freight OD data the estimated utility function can be used as a basic data for forecasting DMT market. 3 alternatives of transportation mode are considered in SP survey; railway, road and DMT. The utility functions are developed according to the freight items, which are container, steel and chemical product. In this study the attribute variable are chosen as time, cost and reliability. The number of level for attribute variables are 3. The high valve is determined as +10% above the standard and the low value -20% below the standard.

• Environmental Analysis Health and Toxicology
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• v.16 no.1
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• pp.1-8
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• 2001

The main purpose of applying the chlorination process during water treatment is for disinfection. Research results, however, indicate that disinfection by-products including trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, and chloropicrin can be produced by chlorination process. Some of these disinfection by-products are known to be potential human carcinogens. This three-year project is designed to establish a standard analysis procedure for disinfection by-products in drinking water and investigate the distribution and sources of specific disinfection by-products. The occurrence level of DBPs in drinking water was below 50$\mu\textrm{g}$/L in most cases. THMs in plant effluent accounted for 48% of all DBPs measured, whereas HAAs accounted for 24%, HANs 14%, haloketones 5%, chloral hydrate 7%, and chloropicrin 2%. Chloroform was found to be the major THMs compound (71%), followed by bromodichloromethane (21%), dibro-mochloromethane (7%), and bromoform (3%), The concentration of DBPs formed in distribution systems increased from those detected in plant effluent. Results would play an important role in exposure assessment as a part of the risk assessment process, and would give basic information for establishment of disinfection by-products reduction and management procedures.

• Journal of Korean Academy of Nursing
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• v.22 no.1
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• pp.68-80
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• 1992

In order to provide data basic to the training of hospice volunteers, this study was carried out to investigate the personal attributes and the Death Orientation of hospice volunteers. 80 hospice volunteers were sampled from those registered on Seoul Catholic Social Service and Korean Association for Volunteers Effort conveniently. Data were gathered from August 16th to October 3rd, 1991. The instrument used for this study was the Death Orientation Questionnaire developed by Thorson and Powell, subjective age and religiosity questionnaire developed by Bell and Batterson, and subjective health criteria developed by Baumann. Data were analyzed using frequency, mean, standard deviation, Chi-square, and t-test by SPSS - program. Result of this study are summarized as follows ; 1. The majority of hospice volunteers perceived younger in their subjective age than their chronological age (65%), Perceived themselves to be healthy subjectively(88.8%), and revealed to have high religiosity score(96.3%) 2. Level of Death Orientation of hospice volunteers was revealed to be moderate.(Mn＝2.06, SD＝0.40, range, 1.45-3.53) Among 25 Death Orientation items, respondents revealed the highest concern over the afterlife (Mn＝3.53, SD＝0.71), revealed the lowest anxiety about not knowing the next world after his or her death(Mn＝1.45, SD＝0.69), and relatively high concern over leaving careful instructions after death (Mn＝2.97, SD＝0.83) Respondents revealed low Death Orientation score(below 1.99) to 12 negative items(2, 3, 5, 6, 7, 9, 14, 17, 18, 19, 20, 22). Thus hospice volunteers seem to be preparing for their own death and shown positive Death Orientation to some items relatively. 3. According to personal attributes (demographic, socioecnomic, and relevant variables) of hospice volunteers, there were no significant statistic differences of Death Orientation score. Thus pre-existing Death Orientation of hospice volunteers and their motive of participation to the hospice service are to be considered important variables influencing the Death Orientation.

• Fashion & Textile Research Journal
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• v.17 no.2
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• pp.227-236
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• 2015

This study analyzed the lower body type of 30's Korean men to develop a slim-fit pants pattern. As the analysis data, direct measurement data of anthropometric measured value in the 6th Size Korea(KATS, 2010) was used as basic data with 481 men in 30's as analysis objects. The result are as follows. First, the result of analyzing factors for the lower body type classification indicated five factors. Second, the result of executing group analysis (with the independent variable of 5 clusters extracted from the factor analysis)classified the following three types. Type 1(36.8%) displayed a medium height of lower body type, small waist and hip, slim and fit body type with a slim shape between the knee and ankle. The shape between the waist and hip had characteristics of a slight curve and short length. Type 2(35.6%) displayed lowest height of a lower body type that was large and thick between the waist and the hip. The drop value of the waist and the hip was small; therefore, the body type was flat with a minimal curve. The underpart type (below the knee) was the thickest and the length was short. Type 3(27.7%) displayed the highest lower body type, a medium level waist size, flat and narrow waist and belly. This body type had a curve with big drop value of the waist and the hip, lower part from the hip to the ankle (including the knee) and a thick calf with along leg.

• Asian Journal of Turfgrass Science
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• v.2 no.1
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• pp.5-30
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• 1988

The object of this experiments was to know the salt tolerance of Fults and other lawn grasses. Fults, Olympic (Tall fescue, Festuca arundinacea Schred), Ceeping red fescue, Kentucky bluegrass and Zoysia grass (Z. japonica S.) were grown in hydroponics with vermiculite at various concentrations of NaCl. Hoagland's solution was used as the basic solution (control), and the concentrations of Cl to it were 1000, 2000, 3000, 4000 and l5OOOppm, respectively. Each was cultivated under the circumstances during 2 months. The results obtained are summarized as follows: 1.The growth of Fults, Olympic, Creeping red fescue and others were better at Cl lOOOppm than control. In the 5OOOppm application, Fescues become worse and 23.9% of them were withered. In concentration of Cl above 9OOOppm, it was impossible to live. 2.In the l0000~l1000ppm application, Olympic and Kentucky bluegrass were become worse and most of them died. 3.Fults were almost possible to live in the below of 9OOOppm, but they began to die in the above of 10000 ppm. 4.With the increasing concentration of Cl, plants were dwarfed and the number of stems, leaves and roots were reduced, but it was especially observed that the number of stolons of Creeping red fescue were increased at 1000~4000ppm. 5.Fults grass was the most salt tolerant turfgrass, but was impossible to live at salt level of about 36 millimhos (Exchange NaCI conductivity-ppm). Among the grasses, according to salt tolerance, they were arranged as follows. Fults > Zoysia japonica S. > Ky belugrass > Olympic grass > Creeping red fescue 6.The number of leaves, stems, tillers, and dry weight of Olympic grass, Fults and others were increased more at Cl 1OOOppm application than control, but in the above 4OOOppm application, those of plants were decreased. 7.The productivity of all grasses under the experiments was increased at 3.l75millimhos (Exchange NaCi conductivity ppm) in the concentration of Cl. The each dry-weight of Olympic, Creeping red fescue, Kentucky bluegrass and Zoysia grass was decreased at 8.85millimhos, and the weight of Fults grass was also decreased remarkably at 12.20millimhos. 8.As the result of this experiments, most plants grow normally at low concentration of NaCI-l000ppm. That seems to stimulate more the grasses to grow than non-salt.

• The Mathematical Education
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• v.50 no.2
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• pp.213-231
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• 2011

The purpose of this study is to analyze the 6th graders' understanding of the concepts of variable on various aspects of school algebra. For this purpose, the test of concepts of variable targeting a sixth-grade class was conducted and then two students were selected for in-depth interview. The level of mathematics achievement of the two students was not significantly different but there were differences between them in terms of understanding about the concepts of variable. The results obtained in this study are as follows: First, the students had little basic understanding of the variables and they had many cognitive difficulties with respect to the variables. Second, the students were familiar with only the symbol '${\Box}$' not the other letters nor symbols. Third, students comprehended the variable as generalizers imperfectly. Fourth, the students' skill of operations between letters was below expectations and there was the student who omitted the mathematical sign in letter expressions including the mathematical sign such as x+3. Fifth, the students lacked the ability to reason the patterns inductively and symbolize them using variables. Sixth, in connection with the variables in functional relationships, the students were more familiar with the potential and discrete variation than practical and continuous variation. On the basis of the results, this study gives several implications related to the early algebra education, especially the teaching methods of variables.

• Journal of The Geomorphological Association of Korea
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• v.24 no.3
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• pp.83-103
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• 2017

Sand deposit with shell units is exposed in Hasa-ri, Yeonggwang-gun, Jeonnam province. We investigated the characteristics of sand sediment topography in the Yeonggwang coastal area to collect evidence of the paleo-environmental change. We performed analysis on particle characteristics, chemical composition, and the age of deposition of sediments. The deposit comprise moderately well sorted medium and fine sand ($1.00{\sim}2.19{\varphi}$). Various sedimentary structures can be observed. Geochemical characteristics change by depth and the degree of variation with depth is small. The results obtained from OSL dating show that sand layers below shell units are deposited 0.32-0.43 ka. As the elevation of the shell unit far mean high water levels or highest high water level, the extensive shell layers could only have been deposited during storm surge conditions. Aeolian processes are discounted due to the size of clasts and the location at which they occur. Results of age dating of the surrounding deposits indicate shell deposits formed after around 300 years age. There is a distinct difference between sedimentary layers including dark brown-black layer. The sedimentary characters such as particle size and geochemistry show difference with depth. It is presumed that depositional environmental in Hasa-ri has changed several times before. This study is expected to contribute to finding an evidence about occurrence of storm surges.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.327-333
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• 2020

BACKGROUND: Through Saemangeum development project, 283 ㎢ of new land is planned to be created and the reclaimed land of 89.7 ㎢ will be used as agricultural land. Therefore, monitoring of soil salinity is required to evaluate the suitability of the land for agricultural purposes. METHODS AND RESULTS: We investigated changes of soil physico-chemical properties, including electric conductivity (EC), of the Saemangeum reclaimed tidal land (1,195 ha) from 2008 to 2017 to obtain basic data for suitable soil management of the Saemangeum reclaimed tidal land. Soil samples were collected from the sites spaced 200 meters apart from each other. Soil analysis results showed that average soil EC was 14.5 dS m-1 in 2008, and decreased to 6.5 dS m-1 in 2014 and to 0.9 dS m-1 in 2017. Accordingly, the soil area below soil EC 4.7 dS m-1 (accepted as farmable soil salinity) increased; 25.0% in 2008, 54.3% in 2014, and 96.9% in 2017. The annual decrease in soil EC was described as y = -1.5756x + 14.6 (R2= 0.96), where y = soil EC and x = elapsed years since 2008. CONCLUSION: The soil salinity have decreased to a level for cultivation of most edible crops. However, since the soil chemical properties, such as soil organic matter were inadequate for the cultivation of crops, it was suggested that management of soil fertility would be important for efficient agricultural use of Saemangeum reclaimed land.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.2
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• pp.15-22
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• 2023

Purpose : This study aimed to analyze the level of understanding of Korean children and adolescents of caries risk assessment items in order to develop caries risk assessment tools. Methods : A total of 52 parents and 108 middle and high school students were analyzed for their understanding of nine items of the CAMBRA CRA for Korean children and adolescents. The nine questions were analyzed through a Likert five-point scale. Centralized distribution analysis was conducted to compare significant differences in the three groups' understanding of the questions. Results : The evaluation of the middle school and high school students' understanding showed that four items scored less than 3.0 points. The items were "Hyposalivatory medications (antihistamines, antipsychotics, asthma, etc.)," "Brushing below once a day," "F varnish last six months," and ".12 % chlorhexidine gluconate mouthrinse daily seven days monthly." The understanding of elementary school parents of ".12 % chlorhexidine gluconate mouthrinse daily seven days monthly" was less than 3.0 points. In addition, as a result of comparing the averages of the three groups, a statistically significant difference (p<.05) was found for a total of five items: "Hyposalivatory medications (antihistamines, antipsychotics, asthma, etc.)," 'Not used oral products such as floss and interdental toothbrushes," "F toothpaste 2× daily or more," "F varnish last six months," ".12 % chlorhexidine gluconate mouthrinse daily seven days monthly." Conclusion : This study was conducted to provide basic data for the development of a caries prevention program by identifying whether the caries risk assessment reconstituted in Korean style can be used for children and adolescents. More than half of the questions scored 3.0 points or higher and were generally completed. Nonetheless, a systematic program can only be completed if a plan is secured to improve repondents' understanding of the questions before a caries prevention program is developed.