• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.4
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• pp.341-353
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• 2022

Pipelines are buried in urban area, and the position (depth and orientation) of buried pipeline should be clearly identified before ground excavation. Although various geophysical methods can be used to detect the buried pipeline, it is not easy to identify the exact information of pipeline due to heterogeneous ground condition. Among various non-destructive geo-exploration methods, ground penetration radar (GPR) can explore the ground subsurface rapidly with relatively low cost compared to other exploration methods. However, the exploration data obtained from GPR requires considerable experiences because interpretation is not intuitive. Recently, researches on automated detection technology for GPR data using deep learning have been conducted. However, the lack of GPR data which is essential for training makes it difficult to build up the reliable detection model. To overcome this problem, we conducted a preliminary study to improve the performance of the detection model using finite difference time domain (FDTD)-based numerical analysis. Firstly, numerical analysis was performed with homogeneous soil media having single permittivity. In case of heterogeneous ground, numerical analysis was performed considering the ground heterogeneity using fractal technique. Secondly, deep learning was carried out using convolutional neural network. Detection Model-A is trained with data set obtained from homogeneous ground. And, detection Model-B is trained with data set obtained from homogeneous ground and heterogeneous ground. As a result, it is found that the detection Model-B which is trained including heterogeneous ground shows better performance than detection Model-A. It indicates the ground heterogeneity should be considered to increase the performance of automated detection model for GPR exploration.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.3
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• pp.363-378
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• 2005

Statement of problem. Hydroxyapatite(HA) coated titanium surfaces have not yet showed the reliable osseointegration in various conditions. Purpose. This study was aimed to investigate microstructures, chemical composition, and surface roughness of the surface coated by the hydrothermal method and to evaluate the effect of hydrothermal coating on the cell attachment, as well as cell proliferation. Material and Methods. Commercially pure(c.p.) titanium discs were used as substrates. The HA coating on c.p. titanium discs by hydrothermal method was performed in 0.12M HCl solution mixed with HA(group I) and 0.1M NaOH solution mixed with HA(group II). GroupⅠ was heated at 180 $^{\circ}C$ for 24, 48, and 72 hours. GroupⅡ was heated at 180 $^{\circ}C$ for 12, 24, and 36 hours. And the treated surfaces were evaluated by Scanning electron microscopy(SEM), Energy dispersive X-ray spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS), X-ray diffraction method(XRD), Confocal laser scanning microscopy(CLSM). And SEM of fibroblast and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay were used for cellular responses of the treated surfaces. Results. The color of surface changed in both groups after the hydrothermal process. SEM images showed that coating pattern was homogeneous in group II, while inhomogeneous in group I. H72 had rosette-like precipitates. The crystalline structure grew gradually in group II, according to extending treatment period. The long needle-like crystals were prominent in N36. Calcium(Ca) and phosphorus(P) were not detected in H24 and H48 in EDS. In all specimens of group II and H72, Ca was found. Ca and P were identified in all treated groups through the analysis of XPS, but they were amorphous. Surface roughness did not increase in both groups after hydrothermal treatment. The values of surface roughness were not significantly different between groups I and II. According to the SEM images of fibroblasts, cell attachments were oriented and spread well in both treated groups, while they were not in the control group. However, no substantial amount of difference was found between groups I and II. Conclusions. In this study during the hydrothermal process procedure, coating characteristics, including the HA precipitates, crystal growth, and crystalline phases, were more satisfactory in NaOH treated group than in HCl treated group. Still, the biological responses of the modified surface by this method were not fully understood for the two tested groups did not differ significantly. Therefore, more continuous research on the relationship between the surface features and cellular responses seems to be in need.

• The Journal of Korean Society for School & Community Health Education
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• v.16 no.2
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• pp.101-114
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• 2015

Objectives: Find out how it affects anxiety situations and self-esteem targeting the critical period of development of self-esteem in the lower grades in elementary school based on laughter therapy in having a positive influence on physical health promotion and positive emotional cultivation. And to verify the effects of laughter activity was to provide preliminary data on mental health education and guidance of school life. Methods: By targeting Ulsan Y elementary school, second grade 7 class, 191 students conducted test self-esteem and anxiety. Homogeneous group of experimental and control groups were selected in each one class. Classified as experimental group carried out laughter activity programs and control group did not carried out. Also the separation of the application program before and after, then it were performed preliminary-post-further as same checklist. Program coverage period is 12 weeks and 30 minutes per session was conducted twice a week. Differences between the experimental group and the comparison group has conducted the independent samples t-test, and if the difference between the experimental group and the comparison group were verified by performing a variance analysis(Oneway ANOVA) and post multiple comparisons. Results: Analysis of the experimental group decreased anxiety in the post-test than the pre-test as a whole, in particular, sub-areas of concern, shame and shyness was shown to be effective, and decision of the difficulty was not significant by insignificant reduction. In addition, self-esteem was increased in overall score. The score of collective self-esteem and School life self-esteem were more increased, and domestic self-esteem was not significant by slight increases. In contrast, the comparison group showed no significant difference in all areas of anxiety and self-esteem of pre-test and post-test. Conclusions: In experiments on self-esteem and anxiety of lower grade in elementary school through laughter activity program, comparison group it did not show an effect by accident, and experimental group showed meaningful effects that self-esteem was increased and anxiety was reduced. Thus, laughter activity can be seen that improving self-esteem, anxiety reduction and etc, is very beneficial to mental health.

• The Korean Journal of Elementary Counseling
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• v.8 no.1
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• pp.95-107
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• 2009

The purpose of this study was to investigate the effect of social skill training on the class cohesiveness of Elementary School students. The experimental group received 12 times of the social skills training for 6 week period. And each training session which lasted for 40 minutes took place twice a week. A total of 59 5th grade students in randomly selected two classes of D Elementary School in N. Gyongsang participated in this study. They were divided into the two groups, again at random; an experimental group(N=30, Male=18, Female=12) and a control group(N=29, Male=15, Female=14). In this study, the class cohesiveness performance test reorganized into 20 items for the level of elementary students by Shin-suk Gang, was applied, after complemented. And, the collected data were analysed through SPSS 14.0. T-test was applied to find out the difference of the average between the experimental group and the control group and the average difference in the pre-and post-test of the experimental group alone, and to see whether the control group and the experimental group are homogeneous. The research design of this study is pre-and post-test control group design. The result of this study is as follows: The result of Independent t-test and Paried t-test on the cohesiveness score and sub-factor scores tells us that the experimental group which received the social skills training showed better achievement that deserves our attention compared to the control group. This result suggests that student's class cohesiveness(class atmosphere, mutual trust, morale, a sense of unity, communication) is positively affected by the social skill training. Accordingly, social skill training which develops class cohesiveness can be an effective strategy for elementary school students to make them more intimate and cooperative with their classmates.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.23-27
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• 1979

Studies on bacterial groups of X. oryzae in Korea has been continued annually since 1975. The present report maintained the result of recent Studies covering on 224 isolates collected front 191 portions of all over the country during the period from 1977 to 1978. The four bacterial groups, I, II, III and V, were found with the ratio of 79, 16, 3 and 3 per-cent, respectively. Variable bacterial groups were found in Chung- nam province while in Jeon- nam province the group II was more pre4valent than group I. Variety-group 'Kimmaze' maintained much more of heterogeneous bacterial groups, and it was significant, especially, on cultivar Milyang $\#23$. Variety-group 'Kogyoku' maintained group II, only while it was possible to isolate group I, II, and III from variety group 'Rantai-emas.' Isolates from Kresek symptom, mostly on Milyang $\#23$, belonged to group I and group II, and their occurring incidence were 20 and 8 out of 28 isolates, respectively. Variability of bacterial group was differed with the location of fields. There were homogeneous and heterogeneous groups, respectively, regardless of host varieties in a given locations.

• Health Policy and Management
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• v.7 no.1
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• pp.55-72
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• 1997

The purpose of this study is to analyze the consumers' demand pattern and the feature of the market for nursing homes, the number of which is tending upwards. The survey data were obtained from the interview of 500 elderly people living in Seoul and Kyung-Ki provincial area. All respondents were 60 years of age and above. The main findings were summarized as follows: 1. The respondents who are less aged, highly educated comparatively, and living with spouse show positive response for the use of nursing homes. The aged living independently and the aged living with unmarried children show higher demand for this facility. Also, the respondents who prefer independent living away from their childrenn, urban areas as their residence and flat-type housing show more interest for the facility. The respondents who are self- supportive, who has no financial supporter, no caretaker, and no domestic helper demonstrate strong inclination to the use of the facility. The respondents who are interested in this kind of facility, acknowledge the necessity of it show strong intention of moving into it. 2. Logistic regression analysis was conducted to understand factors related to the intention of moving into the nursing homes. The group who wish to live separated from their children in the future give 1.78 times more favorable response than the opposite. The group who have an interest in the facility for elderly has 2.02 times higher intention of moving than the opposite. The group who have an intention of using the facility for elderly it is 7.34 times more likely to move into it. 3. The respondents who are the potential consumers for nursing homes can be subdivided. Within the positive group, it could be divided into the group of living independently with the preference of flat-type housing, the group living independently with the preference of separate housing, and the group wishing to live with their children. Within the negative group, the factor of the division is their concern to the facility. Following this study, it can be said that old age people, who have been regarded as one homogeneous group so far, should be recognized as one characteristic individual. This study also shows that the demand aspect yet in its initial stage shold be researched in anticipation of rapid increase. The understanding of diciding factors, the segmentation of potential market will help work out proper strategy, which will contribute to providers' benefit.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.324-330
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• 2009

This study was performed to determine the effectiveness of poloxamer/sodium alginate mixture(PX/SA) barriers on prevention of post-operative peritoneal adhesion in dogs. Fifteen mongrel dogs were divided into three experimental groups: non-treated group, 2% Sodium Carboxymethylcellulose (SCMC) treated group and PX/SA treated group. In order to induce adhesions, the anti-mesenteric serosa of the ileum was exteriorized and then abraded in a standard manner by scraping with a scalpel blade to create homogeneous petechial hemorrhagic surface over a 1 ${\times}$ 1 cm area. Solution of SCMC was allowed to spread across the intraperitoneal organs through a catheter using a syringe. PX/SA was simply coated over the abraded tissues. On day before and day 1, 4, 7, and 14 after operation, venous blood specimens were collected for measurement of RBC, total WBC and fibrinogen. The adhesions were blindly assessed 3 weeks later by using a computerized tensiometer. The RBC, total WBC and fibrinogen values of three groups showed no statistical significances. The mean tensile strength(gram force, gf) of formed adhesions on day 21 after surgery was 173.05${\pm}$113.48 in the non-treated group, 111.42 ${\pm}$ 38.25 in the SCMC group, and 69.00 ${\pm}$ 45.07 in the PX/SA group. The tensile strength values for adhesion seperation in PX/SA group was lower than those in SCMC group(p < 0.05) and significantly lower than those in the non-treated group(p < 0.05). Our data suggested that PX/SA should be effective on reducing peritoneal adhesion formation in dogs compared with SCMC. PX/SA may be applicable to preventing post-operative intraperitoneal adhesion in dogs.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.459-474
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• 2014

The purpose of this study was to investigate the effects of mathematical instruction using GSP program on the symmetrical figures learning and self-directed learning attitude. According to the pretest result, the experiment group and the comparison group showed to be homogeneous groups. The experiment group has learned symmetrical figures for 9 hours using the GSP program and the comparison group has learned for 9 hours using the traditional method(paper and pen lesson). As the posttests, self-directed learning attitude test and symmetry figure understanding test were performed. The results obtained in this research are as follows; First, there was a significant difference in symmetry figure understanding test between the experiment group which learned through GSP program and the comparison group which learned through traditional method. Since there showed a very high achievement in the experiment group which learned using GSP, it can be inferred that GSP was very effective in the lessons of symmetrical movements. Second, there was a significant difference in self-directed learning attitude test between the experiment group and the comparison group. This seems to be because the length of the sides of the figures, size of the angles of the figures etc can be verified instantly and the students can correct by themselves and give feedbacks when they use GSP program. Students preferred drawing using the GSP over drawing using rulers and pencils, and they showed interest in the GSP program and they did not have burden in being wrong in their study and studied in various methods. And as they become familiar with the GSP program, they even studied other contents beyond the scope presented in the textbook.

• Korean journal of communication and information
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• v.36
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• pp.324-347
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• 2006

`Youthism` is pushing the youth research field into a trap of binarism fallacy. It tends to divide the whole population into the young and the old, and further gives an acceleration toward moving the division into the discursive realm of generation gap. The discursive transference is not taking place without any reasonable grounds. The series of discourse is based on two significant phenomena: changes in media background and longer schooling than ever before. Media environment overriding youth culture binds the young in a group and makes them enjoy homogeneous cultural genres. And schooling also seems to play an important role for the youth to have same cultural menus regardless of region, social strata, cultural background. But we need to recognize that after getting into the adulthood, they are not existing in the form of alliance. The youth are not in a homogeneous group. Neither are their culture. The youth are consisted of a variety of groups along such variables as gender, class of their parents. They tend to make distinction not only from the older generation but from the other peer groups. Unless avoiding the trap of youthism, we are blamed for closing eyes to the youth's desire to be distinctive among themselves. Youthism seems to be an active myth even in our academic society.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.76-85
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• 2019

Recently, various investigation of vegetable oil which is extracted from natural resources is being progressed because of its low cost and environmental aspect. However, double bonds in vegetable oil should be substituted to other high reactive functional group due to its low reactivity for synthesizing bio-polymeric materials. ${\alpha}$-eleostearic acid, which is consist of conjugated triene, is the main component of tung oil, and the conjugated triene allows tung oil to have higher reactivity than other vegetable oil. In this study, tung oil is copolymerized with styrene and divinylbenzene to make thermoset resin without any substitution of functional group. Thermal and mechanical properties are measured to investigate the effects of the composition of each monomer on the synthesized thermoset resin. The result shows that the products have only one Tg, which means the synthesized thermoset resins are homogeneous in molecular level. Mechanical properties show that tung oil act as soft segment in the copolymer and make more elastic product. On the other hand, divinylbenzene acts as hard segment and makes more brittle product.