• International Journal of Highway Engineering
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• v.17 no.2
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• pp.55-62
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• 2015

Cracking is an inevitable fact of asphalt concrete pavements and plays a major role in pavement deterioration. Pavement cracking is one of the main factors determining the frequency and method of repair. Cracks can be treated with a number of preventative maintenance actions, including overlay surface treatments such as slurry sealing, crack sealing, or crack filling. Pavement cracks can show up as one or all of the following types: transverse, longitudinal, fatigue, block, reflective, edge, and slippage. Crack sealing is a frequently used pavement maintenance treatment because it significantly extends the pavement service life. However, crack sealant often fails prematurely due to a loss of adhesion. Because current test methods are mostly empirical and only provide a qualitative measure of the bond strength, they cannot accurately predict the adhesive failure of the sealant. This study introduces a laboratory test aimed at assessing the bonding of hot-poured crack sealant to the walls of pavement cracks. A pneumatic adhesion tensile testing instrument (PATTI) was adopted to measure the bonding strength of the hot-poured crack sealant as a function of the curing time and temperature. Based on a limited number of test results, the hot-poured crack sealants have very different bonding performances. Therefore, this test method can be proposed as part of a newly developed performance-based standard specification for hot-poured crack sealants for use in the future. PURPOSES : The purpose of this study was to evaluate both the adhesion and failure performance of a crack sealant as a function of its curing time and curing temperature. METHODS: A pneumatic adhesion tensile testing instrument (PATTI) was adopted to measure the adhesion performance of a crack sealant as a function of the curing time and curing temperature. RESULTS: With changes in the curing time, curing temperature, and sealant type, the bond strengths were found to be significantly different. Also, higher bond strengths were measured at lower temperatures. Different sealant types produced completely different bond strengths and failure behaviors. CONCLUSIONS: The bonding strength of an evaluated crack sealant was shown to differ depending on various factors. Two sealant types, which were composed of different raw materials, were shown to perform differently. The newly proposed test offers the possibility of evaluating and differentiating between different crack sealants. Based on alimited number of test results, this test method can be proposed as part of a newly developed performance-based standard specification for crack sealants or as part of a guideline for the selection of hot-poured crack sealant in the future.

• Korean Journal of Social Welfare
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• v.61 no.4
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• pp.5-33
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• 2009

This study attempted to evaluate the effectiveness of the Supportive Project for the Priority Region of Educational Welfare Investment(SPPREWI) which has been put into action in Korea as a part of national policies for poor school children. In so doing this study aimed to test SPPREWI's legitimacy as well as whether we have to continue this program or not. In order to fulfill this research purpose researchers identified several outcome indicators of SPPREWI, which represent psychosocial and cognitive adjustment. The variables pertaining to psychosocial adjustment domain are: self-concept; depression, anxiety, and suicidal impulse; inclination of assault and indignation; delinquency; school life adjustment; and change in social relations. The variables of cognitive adjustment include recognition of self-control in learning; control strategy of learning behavior; and preparedness for job hunting. In this study the quasi-experimental group contained students from schools which are under the SPPREWI. The control group was composed of students from schools which were free from SPPREWI but under the influence of deteriorating school environment. The quasi-experimental group and the control group were compared in terms of outcome indicators presented earlier. Within the quasi-experimental group both the students below poverty-line and the students above poverty-line were divided into two groups each by the level of service use, and were compared in terms of the outcome variables presented earlier. Study results supported the argument that SPPREWI was effective generally in improving students' school adjustment. Study results also showed that the variable of 'school nurturance' played a significant role in moderating the effect of SPPREWI on a couple of outcome variables specially when schools' overall educational environment was in poor condition. Implication as well as suggestion were presented on the basis of study findings.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.774-780
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• 1999

The study of bond behavior between concrete and rebar has been performed for a long time. On this study, we tried to analysed variation of bond behaviors quantitatively with varying the strength of concrete. Bond stress which observed below the neutral surface of beam and at connecting part of beam and column is affected by various bond parameters. Resistance of deformed bars which embedded in concrete to the pullout force is divided 1) chemical adhesive force 2) frictional force 3) mechanical resistance of ribs to the concrete and these horizontal components of resistance is being bond strength. We selected the most common and typical variable which is concrete strength among various variables. So we used two kinds of concrete strength like as 25MPa(NSC) and 65MPa(HSC). Tension Test was performed to verify how bond behavior varied with two kinds of concrete strength. Concentration of bond stress was observed at load-end commonly in Tension Test of the initial load stage. At this stage stress distribution was almost coincident at each strength. As tension load added, this stress distribution had difference gradually and movement of pick point of bond stress to free-end and central section was observed. This tendency was observed at first and moving speed was more fast in NSC. At the preceeding result the reason of this phenomenon is considered to discretion of chemical adhesion and local failure of concrete around rebar in load-end direction. Especially, when concrete strength was increased 2.6 times in tension test, ultimate bond strength was increased 1.45 times. In most recent used building codes, bond strength is proportioned to sqare root of concrete compressive strength but comparison of normalized ultimate bond strength was considered that the higher concrete strength is, the lower safety factor of bond strength is in each strength if we use existing building codes. In Tension Test, in case of initial tensile force state, steel tensile stress of central cross section is not different greatly at each strength but tensile force increasing, that of central cross section in NSC was increased remarkably. Namely, tensile force which was shared in concrete in HSC was far greater than that of concrete in NSC at central section.

• Journal of The Korean Association of Information Education
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• v.12 no.2
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• pp.213-222
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• 2008

The information society based on Internet has positive effects to provide us with abundance and comfort as well as enhancement of quality of life. But it also has negative effects which bring about more serious social problems than real life. These negative effects of the cyber space are especially critical to elementary school students who do not have good judgment capability and clear concept on cyber space. To solve these problems, we have to let them have ethical sense to respond to the dysfunctions of Internet. We need to enforce Internet ethics education at home and in school so that they can behave as responsible and moral behaviors in this information society. Because the most of the elementary school students usually use Internet at home, the role of their parents can be particularly important factor in Internet ethics education. The purpose of this paper was to identify the current status of the consciousness on Internet ethics of the elementary school students who are the creators of new culture on Internet and their parents who make great influence on their education, and to study what influence the consciousness on the Internet ethics of parents has made on the Internet usage of their children. Through this study, we try to provide the desirable direction for Internet ethics of elementary school students.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.87-97
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• 1999

Rapidly changing healthcare environment and professional nursing practice need a strategy for the organizational development and goal attainment. An understanding of organizational culture could help managers enhance or expend their management strategy, thus increasing the probability of their success in the organization. On the other hand. organizational culture is an abstract concept and can show several views between sciences applying it. Therefore. organizational culture can be described to different ways with roots in each other discipline. Thus. it is necessary to define the concept of organizational culture in nursing perspective. This article reports a study conducted to analyze the concept of Nursing Service Organizational Culture. This study is performed by the guideline of Walker and Avant for concept analysis : selecting a concept. detering aim of analysis, identifying all use of concept. defining attributes. constructing model. contrary, borderline. related cases. identifying antecedents and consequences. According to the results of this study. the following definition attributes of Nursing Service Organizational Culture was suggested. We could define that nursing service organizational culture is the pattern of basic assumption and common belief that shared by the subordinates of nursing service. So, it provides a shared identity for all employees. Attributes of Nursing Service Organizational Culture were defined as (1) it is performed by the result of the interaction through formal. informal communication among nursing service organizational subordinations. (2) it has been performed unconsciously and reacts without ever thinking about the behavior. (3) it makes a unique pattern of behaviors to each nursing organization. which is different from other groups. (4) it has a broad and subtle forces to its subordinates. (5) it provides subordinates with the way of thought and behavior. (6) it influences on the output. stability. and de velopment of nursing service.

• Journal of the Korean Geosynthetics Society
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• v.14 no.1
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• pp.43-50
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• 2015

Lightweight Foamed Soil (LWFS) is a useful material for underground pipe backfill because of reusability of excavated soil and no compaction effect. In this research, a pilot test is carried out and monitoring results are analyzed to investigate behaviors of a flexible pipe, when LWFS is applied as a backfill material. Simultaneously, they are compared with another test case which is backfilled with Saemangeum dredged soil. As a result, the vertical earth pressure of the case backfilled with LWFS slurry presents that decreases as much as 25.6% in comparison with dredged soil and it is only within 10% after solidification. In case backfilled with dredged soil, the horizontal earth pressure is more than 3.6 times of the case used by LWFS and the vertical and horizontal deformation is more than 3.2 and 2.6 times of the case, respectively. It presents excellent effects on earth pressure and deformation reduction of LWFS. The stresses measured at the upper side of the pipe generally present compressive aspects in case backfilled with dredged soil. However, they present tensile aspects in case of LWFS. It is because of negative moment occurred at the center of the pipe due to the buoyancy from LWFS slurry. Conclusively, LWFS using Saemangeum dredged soil is very excellent material to use near the area in comparison with the dredged soil. However, the countermeasure to prevent the buoyancy is required.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.47-52
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• 2008

J.E.N(Joint Enjoyment Network) is the ubiquitous UCC play contents system that provides amusements off-line by utilizing the UCC that people are able to participate in. It is also the entertainment service system that is devised to use contents that could be enjoyed through the cell phone and to make people participate in production, in cases of meeting people off-line during their pastime. The development of this system begins from pointing out the problem of the limitation of the UCC that does participate in production but the produced contents could only be watched, and the UCC only works on-line. The goal of researching this ubiquitous UCC play contents is to suggest the UCC entertainment service system that are available off-line by applying the interactive system to UCC and, by this, to obtain the positive responses about the off-line participating UCC contents. In this research, it chooses scenario and 테스크 performance as the method of deriving the participating UCC from the off-line, and it suggests the ubiquitous UCC play contents system through analyzing the behaviors in each off-line place. Moreover, by developing the prototype that could practically perform the system, it verifies the potentialities of the UCC entertainment service. The anticipation of this study is to make people participate and enjoy not only in production, but also in the contents made. This research will provide the modern people who concern about where to go and what to do with the amusements and will also present a way of new form of contents mixed with UCC and the entertainment service.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.377-387
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• 2020

This study is a retrospective and descriptive research to identify the factors affecting development of spontaneous abortion in women of childbearing age. The subjects totaled 198 females aged 20~45 who had experienced childbirth or spontaneous abortion at least once, and data was collected for one month since July 2019 through self-reporting questionnaires. The results showed that the factors affecting development of spontaneous abortion were use of panty liners (daily: reference, 1~2 times a week: B=-1.74, no: B=-0.77) and antimicrobials (often or a lot: reference, small or normal: B=-0.71, no: B=0.79), occupational groups (inoccupation: reference, service industry employee: B=0.73, white collar: B=1.22, professional: B=0.63, manager: B=1.54), and exposure-risk behavior toward endocrine-disrupting chemicals (B=0.81) during pregnancy, and their explanatory power for development of spontaneous abortion was 24.4% (R²=.24). As a result, it is necessary to prevent endocrine-disrupting chemicals exposure and pay attention to the occupational environment during pregnancy in order to reduce the development of spontaneous abortion.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.419-426
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• 2013

This study was performed in order to suggest the basic informations about the proper oral health babits for kindergarten children, through the investigation of the oral health survey and their oral haelth behaviors. 213 of kindergarten children age 6 were surveyed who has lived at Daegu city and the examined data were analysed by use of spss 18.0 ver.program. The children who had performed the toothbrushing for 3 or 4 times a day, were estimated as high level in voluntary under taking of toothbrushing. It revealed that the low of the caries experience rate in the group of the sabiects who performed toothbrushing at every after meals. On the other hands, both the caries experience index of children who had perfomed toothbrushing with the rolling method and the dental plague index of children who had performed the toothbrushing just the morning time of the oral examination day, wer reveealed as high scores, due to the lack of the abilities to perform the toothbrusing with the proper method. It was needed to educate children for practical performing the toothbrush as well as for traning it with the right way, in order to promote the oral health for kindergarten children.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.9
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• pp.875-883
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• 2010

The thermal performance of LNG fuel tanks of vehicles is determined by the time for non-venting storage of fuel and the amount of fuel supplied to the engine. In this study, we selected a double-walled vacuum-insulated fuel tank with a volume of 450 liter, and the properties of the fuel contained in it were assumed to be the same as those of the methane($CH_4$). For the increasing the non-venting fuel storage time, we propose the use of shielded penetration pipes in the tank. We compared the storage times of the tank used in our study with those of the conventional fuel tank. Further, the additional heat input required to maintain the fuel pressure necessary for an appropriate fuel supply rate was predicted. For these parameters, we derived a thermodynamic relationship that can be used to estimate the rate of increase in pressure for a known heat input, and we obtained equations for estimating the rate of heat leaked by using the established heat transfer model. From the results of numerical computation, we found the non-venting storage time of the tank with shielded pipes to be 25-30% higher than that of the tank with unshielded pipes. Further, we determined the appropriate operation conditions by taking into consideration the transfer rate of additional heat provided to the fuel tank.