• The Journal of Engineering Geology
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• v.21 no.2
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• pp.147-156
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• 2011

We conducted laboratory experiments to determine the physical and mechanical properties, and the failure behaviors, of cements for use as grouting material in a $CO_2$-injection borehole. Samples with lour different ratios of water to cement mass (0.4, 1, 2, and 3) were tested. The analyzed properties (porosity, sonic velocity, modulus, and compressive and tensile strengths) varied systematically as a function of the ratio of water to cement (w/c), showing a sharp change between w/c ratios of 0.4 and 1. Triaxial compression tests revealed a clear boundary between brittle and ductile failure depending on the w/c ratio and confining pressure. The present results can be utilized as input parameters for numerical models to understand the initial deformation and failure behavior of grouting cements in a $CO_2$-injection borehole.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.17-28
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• 2012

This study aims to present the ground for the introduction of energy-saving landscape facilities which can meet the requirements of the age and create a new space by introducing the facilities which saves energy and that users prefer at the space where urbanites enjoy leisure activities in the urban parks. Thus, in addition to a spatial analysis of the parks for 10 urban parks in Gimpo, through an attitude survey on the users' behaviors, the following conclusions were drawn out. First, as a result of putting all facilities in the urban parks in Gimpo, on average, 6.9 out of the standards of 9 (76.6%) have been installed, and as a result of an analysis on the total number of the installed facilities, on average, about 28 kinds of facilities have been installed, so only 22.4% of the total 125 facilities were installed. Second, many urbanites are using the parks for the purpose of taking a walk and exercise to improve their health; however, the legal standards regulate only 2.9 exercise facilities on average in the target area, which are somewhat insufficient. Third, regarding the citizens' intent to participate in responding to climate change, 76% of them showed their intention of participation. Thus, if the energy-saving facilities, the purpose of this study, are introduced, many users will use them, and it is judged that costs for existing street lights and electric power plants will decrease. Fourth, as a result of an analysis of their satisfaction with the facilities, the value of R-square meaning the explanatory power of the independent variables put in a linear model for dependent variables was 0.860, approximately 81% of the total satisfaction, which was a high explanatory power. This study conducted an attitude survey on the users of urban parks in Gimpo at the dimensions of the introduction of energy-saving facilities in the urban parks, the national policies and responses to climate change. It is significant that it identified the appropriateness of developing much more energy-saving landscape facilities needed for low-carbon green growth in various types, and as a subsequent project, a more precision study on this is necessary continuously.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.783-792
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• 2008

While the recent high demand for mega-tall buildings has led to the development of high-performance and high-strength steels, the requirements for architectural-structure-performance steel have been raised as engineers recognize the potential damage that an earthquake can wreak on a tall building. A 600MPa-class steel has emerged to meet such need, and many studies are currently exploring its practical applications on civil engineering works and mega-tall buildings. The available data on the horizontal-force behaviors of structures built with such new steel, however, are still insufficient. There is an urgent need to look into its design data, especially its toughness, and to compare the plastic strain ratios of column-to-beam connections using high-strength steel and regular steel. One of the first studies on the behavior of a column-to-beam connection using 600MPa-class steel (SM570 TMC), this thesis analyzes such steel's structural performance by conducting a structural test on seismic resistance on a full-scale column-to-beam welded connection with non-scallop and recommended-scallop details. Compared with the previous studies on SM490, this thesis evaluates the weldability of SM570 TMC and presents the latter's seismic design data for use in testing its practical application.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.870-883
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• 1997

The health center has to play an important role in promoting community health and satisfying a variety of community health needs and demands in the decentralized Korea. The nearly enacted Community Health Act compels every health center to make its own health plans which intend to deal with local health problems and plan its future health care. This obligation is obviously a big burden to most health centers. They do not have experiences in and abilities of making local health care plans. In order to establish a systematic community health plan, health centers have to concentrate their efforts on enhancing the ability of making health care plan through gathering and analysing the local health informations. However, it is very difficult in reality. This is simply because it will take long time to accomplish these activities. It seems natural that various professionals and researchers participate in carrying out the process of making community health plan in the initial stage. No standardized methodology and analysing framework exist even in the health professional society. Nonetheless, it is common to introduce survey research methodologies in analysing consumer's health care utilization and cost, and in identifying factors influencing health behaviors. Many researchers and professionals have applied social survey methodologies in obtaining information on providers and health policy makers as well. The authors have found that few studies have ever utilized local health data stored at the self-employed medical insurance society as the data source of planning activities. The purpose of this study is to illustrate the usefulness of the data stored at the Sung-Dong Gu Self-employed Medical Insurance Society in establishing the community health plan. The major contents of this study are as follows ; 1. frequency of utilization by age, area, sex, type of medical care institutions, and some major diseases 2. Medical treatment by type of medical care institutions, by classification of 21 diseases, by frequency of three-character categories 3. Medical treatment of major neoplasm and some chronic diseases by age, sex, and area. The conclusion of this study is that it is of great potentiality to find out the local health problems and to use them in blueprinting the community health plan through comparing the frequency of medical utilization analyzed by a variety of variables with NHI health data or the health data from survey research.

• Information Systems Review
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• v.18 no.2
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• pp.199-223
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• 2016

As social networking services (SNS) become widely used tools for maintaining social relationships, people use SNS to express themselves online. Users are free to form multiple characters in SNS because of online anonymity. This phenomenon causes SNS users to easily demonstrate multiple personas that are different from their identities in the real world. Therefore, this study focuses on online multi-personas that establish multiple fake identities in the SNS environment. The main objective of this study is to investigate factors that affect online multi-personas. Fake online identities can have various negative consequences such as cyber bullying, cyber vandalism, or antisocial behavior. Since the boundary between the online and offline worlds is fading fast, these negative aspects of online behavior may influence offline behaviors as well. This study focuses on teenagers who often create multi-personas online. According to previous studies, personal identities are usually established during a person's youth. Based on data on 664 teenage users, this study identifies four emotional factors, namely, closeness with others, relative deprivation, peer pressure and social norms. According to data analysis results, three factors (except closeness with others) have positive correlations with users' multi-personas. This study contributes to the literature by identifying the factors that cause young people to form online multi-personas, an issue that has not been fully discussed in previous studies. From a practical perspective, this study provides a basis for a safe online environment by explaining the reasons for creating fake SNS identities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.1-9
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• 2014

Recently, natural aggregate was adequate to supply the demand due to increase of building construction. National pollution induced by construction waste caused by the reconstruction and redevelopment was cited as the major social issues in Korea. Therefore, government are required by law to use the recycled aggregate. In order to consider safety, KS F 2573 recommend that recycled aggregate with below design strength 27MPa and replacement ratio of 30%. This study on flexural behaviors of reinforced concrete beam was conducted and the specimens employed in test were planed with high strength concrete (40, 50 and 60MPa) and recycled aggregate replacement ratio (0, 30, 50, 100%). Although the flexural strength of reinforced concrete beam has trendy to decrease with increase of replacement ratio, it is meet to KCI 2007. The comparison results show that reinforced concrete beam using recycled aggregate can apply as flexural member in building construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.55-63
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• 2018

Recently, the use of duplex stainless steel which with a two-phase microstructure (equal mixture of ferrite and austenite) has been increased in a variety of industrial fields due to higher strength leading to weight saving, greater corrosion resistance(particularly, stress corrosion cracking) and lower price. However, currently, stainless steels are not included in the structural materials of Korean Building Code and corresponding design standards are not specified. In this paper, experimental studies have been performed to investigate the structural behaviors of duplex stainless steel (STS329FLD) bolted connection with two bolts for providing the design data. Main variables are shear connection type (single shear and double shear) and end distance parallel to the direction of applied force. Fracture modes at the final step of test were classified into typical block shear fracture, tensile fracture and curling. Curling occurrence in single shear connection led to ultimate strength drop by up to 20%. Test strengths were compared with those by current design specifications such as AISC/AISI/KBC, EC3 and AIJ and proposed equations by existing studies. For specimens with no curling, Clement & Teh's equation considering the active shear plane provided a higher strength estimation accurancy and for specimens with curling, Kim & Lim's equation considering strength reduction by curling was also overly unconservative to predict the ultimate strength of curled connections.

• Journal of Korean Home Economics Education Association
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• v.18 no.4 s.42
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• pp.25-38
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• 2006

The purpose of this study was to investigate the education effect of eating habit unit in 'technology home economics' upon nutrition knowledge eating befavour of students. The eating habit unit in 'technology home economics' was taught with respect to 509 middle school 1st grade students, and preference acknowledgement were examined. Education effect was also examined by analyzing the changes in nutrition knowledge and eating befavour due to the education. Study results revealed that the level of acknowledgement for eating habit unit was positive while majority of the students thought that education contents were emphasized on the theory mainly because of insufficient class hours. Therefore, in order to let students know them better and make the best use of them, it is required to increase the class hours and research opportunity for practice class related with daily life. Through the middle school 'technology home economics' eating habit unit education, positive effect in part of eating habit area was observed and nutrition knowledge was enhanced after the education in both male and female students group. Judging from the results, less enhancement was observed in eating habit compared to the nutrition knowledge increase. Therefore, it can be concluded that continuous and a long range nutrition education is needed to transform the acquired nutrition knowledge into eating habit.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.9-20
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• 2015

Nowadays, Smart Wallet technology trend that is able to save users' consuming costs and also retain users' redundant behaviors such as Single-tapping, One-way communication, Integrated ID, has been issued in recent Mobile Industrial Fields. As one of Smart Wallet functions, Integrated ID is proposed for users' convenience, handiness, and immediate responses. It is designed for the effective management of users' IDs which are easy to be forgot because of its unusual structures. To be detail, instead of user, Integrated ID system can certificate users identification from various online sites (where user resisted) authorization requests via one-clicking, not putting identification data in each sites. So, this technology would be helpful much to a certain user who has lots ID and its Password in multiple Online shopping companies by establishing integrated ID. However, although Integrated ID has lots advantages to be used, most Mobile Service Companies has hesitated to apply Integrated ID service in their shopping systems because this technology requires them sharing their users' data. They have worried that this service would be not helpful to gain their profits. Furthermore, Users who join in multiple shopping companies and use Integrated ID services also are difficult to decide which company they have to save their points in before payment because this system could not show any financial benefit analysis data to their users. As following facts, via this paper majorly we propose the advanced Integrated ID system which concern shopping point management. Basically, this system has a strong security payment service and secure network services like other mobile Shopping systems. Additionally, this system is able to service (or to support) shopping -point -saving guide for customers' financial benefits and conveniences.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.141-153
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• 2015

This paper is an attempt to analyze the comparative advantage of Busan Port to China. For this, we use the market comparative advantage index, which is a version of the revealed comparative advantage index. The market comparative advantage index (MCA) uses trade patterns to identify the sectors in which a region has a comparative advantage, in this case by comparing Busan Port's trade profile with the world average (China). The indices are calculated at the commodity level of the HS four-digit classification. The export data used in this study are obtained from the Korea International Trade Association. Exports to China accounted for almost one third of Korean exports in 2014. There are, however, structural differences among the main export items of Busan Port. This paper, therefore, employs MCA indices to reveal the behaviors of the ten main export items, which are "HS3920-other plates/sheets/film/foil of plastics," "HS7606-aluminum plates/sheets/strip," "HS8479-unspecified machines/medical appliances," "HS8486-machines for semiconductor devices or wafers," "HS8529-parts for transmission apparatus for television," "HS8703-motor vehicles for the transport of persons," "HS8708-parts of motor vehicles," "HS9001-optical fibers," and "HS9013-liquid crystal devices." The study shows that export competitiveness of nine items increases, the exception being HS8703. However, China's import ratios of seven of the nine items for which the MCA indices go up are on the decrease, which means that it would be hard to expand the export market for these seven items, despite the higher MCA indices. Since the shares of the port's total exports to China of HS3907, HS8486, HS8529, HS9001, and HS9013 in total exports to China increase together with China's import ratio decreasing, these items may have promising export markets. MCA increases of HS7606 and HS8479 are attributable to China's lower import ratio, rather than a higher export share, so higher MCA indices do not guarantee higher export competitiveness for these items.