• International Journal of Highway Engineering
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• v.6 no.1 s.19
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• pp.47-56
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• 2004

To determine the pure bond strength between substrate and its overlayed concrete material, a direct pull-off test method was introduced by using a bi-material cylinder with which a penny-shaped crack was mountained at its interface. First, to evaluate the stress magnification or concentration at the interface, the energy release rates of a penny-shaped interface crack in remote tension loading on a bi-material cylinder were determined in terms of different modulus ratios and undonded area ratios(crack ratios) using a commercial finite element program. Then the energy release rates were calibrated as non-dimensional values in consideration of structural dimensions and applied forces. And to evaluate whether this new pull-off test method gives sound test results, three different sizes of unbended area ratios were incorporated along their interface in bi-material cylinders(sulphur polymer concrete + old concrete). Test results showed that all specimens were broken off at their interfaces as intended. Also the FEM analyses and test results indicated that a bi-material specimen with unbended area ratio of 0.4$\sim$0.6 is suitable for best accurate testing.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.224-233
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• 2016

Embedded Railway Systems (ERS) will be adapted for wireless trams and will be constructed along city roadways. An asphalt layer should be overlaid on top of the concrete slab used as the trackbed structure in order to ensure smoothness and surface levels equal to those of existing road pavement in downtown city areas. However, the characteristics of an asphalt layer when used as overlay pavement for an ERS are complicated and the behavior of this material is not yet well defined and understood. Therefore, in this study, laboratory shear and tensile bond strength tests were conducted to investigate the bonding behavior of an asphalt layer in a multilayered trackbed section of an ERS. For the laboratory tests, a waterproof coating material was selected as a bonding material between the asphalt overlay and a concrete specimen. Valuable design parameters could be obtained based on the tensile and shear bond strength test results, providing information about the serviceability and durability of the overlaid pavements to be constructed alongside the ERS for wireless trams. In addition, a deformation analysis to assess the tensile strain generated due to truck axle loads at the interface between the asphalt layer and the concrete slab was conducted to verify the stability and performance of the asphalt layer.

• 대한공업교육학회지
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• v.41 no.1
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• pp.88-107
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• 2016

Hatching and developing great human resource is getting important in these competitive business environments. It is important to define and utilize personalized competence model for individual firm before hatching and developing its HR. Competence is a unique set of behavior shown as a result of sum of knowledge, skill, value and other personal traits in his/her working environment and the systematic process finding and defining the competence is called competence modeling. The purpose of this study was to perform competence modeling for a small-medium size IT firm N especially for its salespeople and offer suggestions of the usage of the result. Competence model was developed by 'Covering general model' suggested by Dubois. To confirm the validity, survey and workshop was conducted and the model was finalized based on the results. As a result, total 14 core competencies were found and defined by the core salesperson of the firm N. Also the competencies were categorized into three based on the timing of the usage. Additionally, this study offers the ways to utilize the result as foundation for competence based HR system and HRD program for firm N.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4635-4642
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• 2010

Latex modification of concrete provides the material with higher flexural strength, as well as high bond strength and reduced water permeability. One of the most advantages of the very early-strength latex-modified concrete (VES-LMC) could be the similar contraction and expansion behaviour to normal concrete substrate, which enable to ensure long-term performance. The purpose of this study was to parametric nonlinear flexural nonlinear analysis of RC beam rehabilitated by VES-LMC. The results were as follows; The flexural nonlinear analysis model of RC beam overlaid by VES-LMC in ABAQUS was proposed to predict the load-deflection response, interfacial stress, and ultimate strength. The proposed FE analysis model was verified by comparison of an experimental data and the FE analysis results. The FE analysis results showed that yield point as well as flexural stiffness increased as the depth increased; the stiffness of beam overall increased as the bond stiffness became larger; the bond strength between two different materials is a key factor in composite beam. A parametric study showed that an overlay thickness was a main influencing factor to the behavior of RC beam overlaid by VES-LMC.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.737-744
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• 2021

Spray paving minimizes material lost during the construction or repair of a road surface, and it can be done in conjunction with tack coating. This approach involves applying the asphalt mixture at the same time as spraying the tack coat by attaching a spraying device to the asphalt paver. When applying an asphalt overlay to an aged concrete surface, it is important to ensure the adhesion performance between different material properties. Accordingly, there is a need for a tack coat that can be applied by spray paving and that exhibits good adhesive performance on different materials. In this study, bonding strength tests under various conditions were performed to evaluate the basic performance of a tack coat developed for use with a spray paver. The bonding performance of the tack coat was observed to be affected by curing conditions and material lost during construction. The test results also showed that the tensile and shear bonding strengths of the developed tack coat were 1.21 and 1.99 times higher than those of a conventional one, respectively. As a result, the developed tack coat is considered suitable for application to spray paving.

• Korean journal of communication and information
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• v.67
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• pp.177-208
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• 2014

This study inquires how human interest news on society section of newspapers had been modulated as multi-layered political narratives that would consistently have Koreans consider, realize and question on colonial situation as well as ethnic identity. Under totalitarian censorship of the colonial government, newspapers could not publish reports on political issues and current affairs, so society page of human interest such as crime, accident, conflict, disaster, and many kinds of sufferings of peoples to death would take great public attention and consequently be considered as a substitute of political section. Society page had enjoyed its influence on formation of public opinion of the colonized ethnic society and had maintained cultural-nationalist position ever since the founding of newspaper in mother-tongue in 1920. In colonial context, there is nothing non-political to the lives of the colonized, social facts would be necessary and happen to be modulated into a narrative that could trigger nationalist sentiment. For this end, news reporting of society section usually concentrated on aspects of 'Les Mis${\acute{e}}$rqbles', dramatic quality, and psychological factors in detail. Narrative style of news reporting got used to modulate factual informations with a proper taste of exaggeration, emotional expression, and commercial touch of exciting words. Even in a case of death by drug abuse, news was written to indicate what made him/her drive to miserable death on street, that is, what is de facto reason of all of social problems like as migration, hunger, leaving home, crime, suicide, violence, gambling, love affairs to death, adultery, and even opium habit. Those social problems and personal sufferings appeared up on newspaper 3rd page at daily base. Readers could acknowledge and identify what the real matter that should be resolved and then blame colonialism, capitalism, and militarism for those social problems. Journalists put values on inciting the colonized to realize the national and ethnic situation and feel sympathy for their people tied up by a common destiny. In this terms, news on society section of newspaper under Colonial Occupation were encoded as narratives of politically layered text and then decoded as intriguing sentiments against colonial dominance. I argue that society page of newspaper of colonial period engaged in a sort of cultural politics of sentiment and emotion which is a private area outside of imperial sight.