• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.585-596
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• 2012

In this study, the flexural characteristics of reinforced polymer concrete T-beams strengthened with GFRP, typically used for bridges and parking structures, are investigated. A method to determine the flexural failure mode of reinforced polymer concrete T-beams comprised of compression failure (CF), tension failure (TF), and fiber sheet failure (FF) for different levels of GFRP strengthening is proposed. Moreover, the present study provides a formula to calculate the design flexural strength for each failure mode. In reinforced polymer concrete T-beams strengthened with GFRP, an ideal failure mode can be achieved when the failure occurs in the following order: 1) yield of steel reinforcement, 2) failure of GFRP, and 3) compression failure of concrete. In the case of FF mode, due to GFRP failure before the polymer concrete crushing in compression region, a concept of equivalent rectangular block based on the ultimate limit state of concrete should not be used. Thus, this study suggests an idealized stress-strain curve for polymer concrete and finds parameters for stress block, ${\alpha}$ and ${\beta}$ based on the strain distribution in polymer concrete. Furthermore, the present study suggests an aspect ratio of 2.5 by examining the compressive stress distribution and design flexural strength characteristics for different aspect ratio of T-beams. This study also provides a design flexural strength formula, and validates its acceptability based on experiment and theoretical analysis.

• Journal of Families and Better Life
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• v.20 no.5
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• pp.149-166
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• 2002

In this study, 1 have analyzed the state of the use of information technology by the at-risk children who are residing in Husan metropolitan area. The ultimate goal of this study is to help ensure the healthy development of the children and improve the quality of their lives in this information-oriented society. For this research, 1 surveyed 183 children living in an institution or a low-income family in Busan metropolitan area. The survey questionnaire was designed to obtain information on the respondents, socio-demographic characteristics, computer-related conditions of the immediate and social environments, patterns of computer and Internet use, their experience and degree of so called, Net-generation syndrome, Internet addiction disorder, changes in social and familial life caused by Internet use, and exposure to pornographic materials. The results show that 95.9 % of at-risk children in Husan own a computer, 60.9 % of those computers being Pentium Ⅲ. A majority of the children (74.9 %) are connected to Internet at a high-speed, using such devices as LAN, ADSL or cables. About seventy-six percent of the children have used a PC and Internet less than two years. In other words, a majority of them have not used those for a long period of time. The main results of the research are summarized in the following: There is a significant difference among at-risk children in terms of experiences in computer and Internet use according to their grade levels. There is a gender difference in the amount of time spent on computer and Internet. Boys spend more time every week on computer and Internet than girls do. There is a significant difference in the pattern of computer and Internet use, according to the type of their risk, and grade level. The so-called 'Net Generation Syndrome' is not serious in this group. A majority of the at-risk children think that Internet is more interesting than TV. They hardly shop on Internet, and they don think the advertisements on Internet are a serious problem. Also, unlike many people assumptions, their desire to communicate through on-line chatting was very low. They do not tend to buy computer game programs, and Internet Addiction Disorder was not pronounced among them. The at-risk children rarely had an exposure to pornographic materials in the cyber space. However, the exposure was more frequent for institutionalized children than children in low-income families. These results point to a need for a policy to improve the welfare of at-risk children and guarantee their right to information.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.685-700
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• 1997

The ultimate aim of periodontal treatment is periodontal regeneration, which necessiates the regeneration of bone tissues. This paper investigated the effect of growth factor on bone cells. Platelet-derived growth factor(PDGF) is the one of the polypeptide growth factor that has been reported as a biological mediator which regulates activities of the cell proliferation, migration and metabolism of undifferentiated mesenchymal cells. The purpose of this study is to evaluate the effects of PDGF on bone nodule formation and ALP activity of MC3T3-El cells. Cells were seeded at $1{\times}10^5cells/well$ in alpha-modified eagle medium containing 10% fetal bovine serum, lOml beta-glycerophosphate and $50{\mu}g/ml$ of ascorbic acid. PDGF 0, 0.1, 1, 10 ng/ml were added to the cells at a confluent state and cultured for 3, 7, 14, 21, 28 days. We examined bone nodule formation and alkaline phosphatase activity. The results were as follows : There were bone nodule formation at day 21 both in control and all the experimental groups, and at day 28, all the experimental groups showed much more bone nodules than control groups. Compared to control-l group, ALP activity was increased in PDGF O.1ng/ml group and was decreased in 1,10ng/ml PDGF treated groups.{P< 0.05, P< 0.01) Compared to control-2, ALP activity was decreased in all the experimental groups except PDGF 0.1ng/ml in 21 day group. In the time-response effect, ALP activity was increased by the day 14 in all the experimental groups and thereafter ALP activity was decreased.(P<0.05, P< 0.01) In the dose-response effect, ALP activity was decreased as the dose of PDGF was increased, and after 21 day ALP activity was lowest in 1 ng/ml group, ALP activity was highest in the day 7 in control group and 0.1 ng/ml, 14 day experimental group. In conclusion, PDGF is considered more effective in the proliferation than differentiation of osteoblast-like cells, and it may be useful to study the combined effect of PDGF and other growth factors on osteoblast-like cells.

• Korean Parent-Child Health Journal
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• v.4 no.1
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• pp.1-18
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• 2001

Fatigue after delivery affect women's birth experience and interrupt the process of labor. Finally woman cannot have a positive birth result and will experience a postpartum fatigue. But researches about fatigue during the labor are lacked. Nurse help adapting a mother's role, bonding with new baby, recovering after birth, and improving woman's quality of life through decreasing fatigue during the labor and intercepting a continued postpartum fatigue. So it is very important that measuring a fatigue and confirming relationships between fatigue and factors affecting fatigue. The purpose of this study was measuring the level of fatigue within 4hours after delivery and identifing factors affecting fatigue. The ultimate goal was to contribute to improving a birth experience and adapting after birth through decreasing the level of fatigue and interventions. The data was collected for this study at the hospital of two universities and the third hospital in Seoul from Aug. 15. to Nov. 10. 2000. The subjects were 106 of mothers who deliveried a normal newborn and were tested within four hours after birth. The instruments were The Visual Analogue Scale for fatigue, The State Anxiety Inventory, and The Labor Support Inventory. The data were analyzed by using percentage, mean, SD, t-test, ANOVA, Pearson correlation. The results of this study were as follows; (1) The level of fatigue during the labor was 61.48point. (2) The deferences according to general and obstetric character affecting fatigue founded that there were Significant differences according to job(t=2.659, p=0.009), and the type of delivery(t=-2.035, p=0.044). (3) The deferences according to factors affecting fatigue revealed that there was significant difference according to quality of sleep(F=2.935, p=0.037). The significant fatigue and the fatigue after delivery was anxiety(r=0.343, p=0.000). The above findings indicate that the level of fatigue during the labor is higher than during pregnancy and postpartum. Woman having a job, delivering by vacuum was more fatigued. The level of fatigue according to a quality of sleep was significant difference. The poor quality of sleep, higher level of fatigue. And the more anxiety after delivery, the more fatigue. So, the variable nursing interventions for lessening the level of fatigue through appling the situation for rest, relaxation during the labor to reserve energy, and decreasing anxiety should be provided for mothers.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.831-836
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• 1998

The B1914 Ni-base superalloy was manufactured according to crystal structures of poly-, directionally solidified- and single crystals. We observe deformation as type of different crystal structure from room to high temperature. Specimens are controled by cooling rate and thermal gradient and then heat treatment in vacuum and then cooling with Ar gas. Different crystal structure has different stress-strain characteristic. At $600^{\circ}C$, yield strength and ultimate strength is increased single-, directionally solidified- and poly crystals in order.

• Journal of Society of Preventive Korean Medicine
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• v.9 no.1
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• pp.17-36
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• 2005

The objective of this study is to present basic data for producing tools to measure Yangseng of the elderly aged older than 65 by reassessing the validity and reliability of such tools already developed. In the present study, total 855 subjects were divided into 4 groups and given 31 question for the ultimate factor analysis of each item. The results cloud be summarized as follows: 1. In case of 'don't have sex in drunken state or right after dinner'(the 31st item of sex live yangseng). factor loading came out proportionally in 3 factors such as factor 4=0.358, factor 5=0.389 and factor 6=0.386. As they all failed to reach the general standard of 0.5 or more and even the minimum standard of 0.4 or more, the 31st item was deleted from the questionnaires. 2. From the factor analysis after exclusion of the 31st item, factor loading of the 25th item of sleep yangseng 'go to bed and get up regularly' appeared to be proportional in 2 factor(factor 4=0.393 and factor 7=0.373). Since it was shown that the 25th item could not be classified into a category but interacted with others in common and didn't satisfy the minimum standard of 0.4, it was deleted form the questionnaires, too. 3. From the factor analysis conducted after excluding the item numbers 31 and 25, factor loading of the 12th item of diet yangseng 'do not eat much' turned out to be relatively high with such values as factor 5=0.518 and factor 3=0.453. As it was, however, tied up with the factor of exercise yangseng, it was also deleted. In conclusion, 28 items after excluding the item numbers 12, 25 and 31 form 4 group showed the same results as divided into 8 factor with high grade of reliability and validity, evidencing the assumption that they can be employed practically to measure yangseng of the elderly aged 65 and oder.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.303-312
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• 2007

Steel box girder bridges are being commonly designed for medium-span bridges of span length. Composite truss bridges with steel diagonals instead of concrete webs can be an excellent design alternative, because it can reduce the dead weight of superstructures. One of the key issues in the design of composite truss bridges is the joint structureconnecting the diagonal steel members with the upper and lower concrete slabs. Because the connection has to carry concentrated combined loads and the design provisions for the joint are not clear, it is necessary to investigate the load transfer mechanism and the design methods for each limit state. There are various connection details according to the types of diagonal members. In this paper, the joint structure with group stud connectors welded on a gusset plate is used. Push-out tests for the group stud connectors of were performed. The test results showed that the current design codes on the ultimate strength ofthe stud connection can be used when the required minimum spacing of stud connectors is satisfied. Flexure-shear tests were conducted to verify the applicability of the design provisions for combined load effects to the strength of joint structures. To increase the pullout strength of the connection, bent studs were proposed and utilized for the edge studs in the group arrangement of the joint. The results showed that the details of the joint structure were enhanced. Thereafter, design guidelines were proposed.

• Fire Science and Engineering
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• v.17 no.3
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• pp.31-44
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• 2003

In the Local Autonomy Law, we regard the fire-fighting service as inherent service for the local government. However, if we look into the course of the charge of fire-fighting service, after the transfer of this from the police service, or the state, to the local service in 1991, this is now taking a firm hold as service of the local government. what we call the local services includes the business about the welfare of the residents and that of taking in charge of the resident properties, proclaimed in the Constitution. That is to say, the basic purpose of the local autonomy is to make the residents feel the most convenient and safe, and this is the mission of the present-day local autonomy. Looking from this point of view, if we consider that the ultimate purpose of fire-fighting is promoting the welfare of the residents by preventing and putting out fires and, in the time of emergency, carrying out rescue and relief operations, and furthermore, maintaining the safety and order of a society, until present time the benefits of fire-fighting business were mainly available to the residents of the cities. In order to break from these thoughts, according to the result of comparing and analyzing the metropolitan city, surrounding rural areas, middle and small cities and typical rural areas, the rural areas are urgently demanding fire-fighting service, so it is being proved that it is necessary to install the offices in these areas. Therefore, the installation of the fire-fighting offices in the counties that are the basic units of the primary local autonomy and are rural areas should be expanded as part of the welfare administration.

• Journal of the Korean GEO-environmental Society
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• v.16 no.9
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• pp.33-41
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• 2015

The vertical bearing capacity of a bucket foundation installed in sand can be calculated as sum of the skin friction and end bearing capacity. However, the current design equations are not considering the non-associated flow characteristics of sand and the reduction in the skin friction and increase in the end bearing capacity when the vertical load is applied. In this study, we perform two-dimensional axisymmetric finite element analyses following non-associated flow rule and calculate the vertical bearing capacity of circular bucket foundation of various sizes installed in sand of different friction angles. After calculating the skin friction and end bearing force at the ultimate state, design equations are derived for each. The skin friction of bucket foundation is shown significantly small compared to the end bearing capacity. Considering the difference with the available design equation for piles, it is recommended that the equation for piles is used for the bucket foundation. A new shape-depth factor ($s_q{\cdot}d_q$) for bucket foundation is recommended which also accounts for the increment of the end bearing capacity due to skin friction. Additionally, the shape and depth factor of embedded foundation proposed from the associated flow rule can overestimate the bearing capacity in sand, so it is more adequate to use the shape-depth factor proposed in this study.

• Journal of Cadastre & Land InformatiX
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• v.45 no.1
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• pp.31-43
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• 2015

In the past, the main function of land use categorization was merely used for basic data for taxation purpose, but recently land use categorization is used as important reference data in various ways, including administrative affairs, national land plan, land development, city maintenance as well as private transactions of land, in addition to the provision for assessment data. In the future, it can be expected to broaden its own functions. For expansion of the function of land use, we need to reconsider categories of land use from a perspective of individual laws and regulations actually regulating land use from a perspective of demand. In order to resolve any discrepancy between actual land use and land use on official books, the ultimate method of resolution is to study the current state of actual use of land and reflect them on official books, but it is also necessary to prevent any confusion of national people by unifying various categories of land adopted by the regulatory acts related to land. In addition, if the same administrative regulations are applied to different land use under the current laws, it is necessary to include them in the land of the same category. This study proposes to establish a new category for securing systematic consistency of the current categories of land use under the integrated cadastral act with other land laws and regulations.