• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.1-5
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• 2018

The present study investigated the characteristics of vertical sagging down of high temperature in chamber and characteristics of vertical sagging down in the outdoor asphalt sheet and asphalt seal under korea ltimate condition using asphalt seal products of solvent based type, solventless type, water dispersion type, and heat melting type, which are currently applied in Korea. Prior to the investigation of outdoor vertical sagging down characteristics, the assessment of sagging down performance of single use of sealing products at $20^{\circ}C$, $40^{\circ}C$, $60^{\circ}C$ was conducted and the result showed that sagging down did not occur at $20^{\circ}C$ but some solventless type, water dispersion type specimens at $40^{\circ}C$ had sagging down up to 10 mm. In addition, some solventless type, water dispersion type specimens had sagging down up to 55 mm at $60^{\circ}C$. For specimens to which asphalt seal and renovated asphalt sheet were layered over the outdoor concrete vertical surface, sheet sagging and sagging down occurred up to 50 mm in water dispersion specimens after three month later since the construction in summer.

• Journal of Science Education
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• v.34 no.1
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• pp.140-154
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• 2010

The core of subject matter education is determined by the choice of subject matter taught to students and by the organization of content according to educational objectives. The purpose of this research is to suggest ways to improve the present content of science education so as to prepare students and schools for a radically different future. We deduced the main issues the solution of which could lead to significant improvements in the contents of science education by analyzing previous studies and investigating the changes in content that were effected during curriculum revisions in the past. The main issues thus revealed through this study are as follows: the essence of the contents of subject matters in science education, the social and cultural background of change in the science curriculum, the rational steps on the way to choosing contents as part of the science curriculum, the processes of choosing the main contents of each subject, the international comparative study of contents, the updating of contents for the benefit of future society, and the reorganization of subject contents. In order to find a concrete improvement on the issues deduced, we organized an expert group. Then, we proceeded to collect and analyze the experts' opinions. A survey was administered to 19 science education experts working with universities and colleges of education. We examined their degree of agreement on the issues and problems, and on the steps that may be taken to us the improvements on these issues. we suggested that: collecting opinion and reaching an agreement on the essence of the contents of the subject matters in science education, the necessity to choose core contents within the scientific domain, developing a structure map in order to integrate and connect various subject domains, presenting explicitly the objective of inquiry by grades, moving toward integrating science contents, diversifying the construction of science textbooks.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.10-18
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• 2018

The primary purposes of this study are to understand a fundamental aspect of current uniformity around a reinforcing bar (rebar) in cement mortar, and to develop an accurate monitoring method in a wet-dry cycling process with the alternative current (AC) impedance method. Three cement mortar specimens with two embedded rebars were prepared in the laboratory. As a main variable, the distance between two rebars was designed to be 10, 20 and 30 mm with the same thickness of 20 mm. To simulate the corrosion of rebars in concrete structures in a marine environment, three cement mortar specimens were exposed to 15 wet-drying cycles (24-hour-immersion in seawater and 48-hour-drying in a room temperature) in the laboratory. It was observed that the potential level shifted to a noble value during corrosion potential monitoring, which is attributed to acceleration of dissolved oxygen diffusion at the drying process. AC impedance was measured in a frequency range from 100 kHz to 1 mHz on a wet-drying process. A theoretical model was proposed to explain the interface condition between the rebars and cement mortar by using the equivalent circuit consisting of a solution resistance, a charge transfer resistance and a CPE (constant phase element). It was observed that the diffusion impedance appeared in a low frequency range as corrosion of rebars progresses. At the drying stage of the wet-drying cycles, the currents line for monitoring tended to be non-uniform at the interface of rebar/mortar, being phase shift, ${\theta}$, close to $-45^{\circ}$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.100-107
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• 2018

The objective of this study is to assess the strengthening effects of fiber reinforced polymer(FRP) sheets such as Carbon fiber, Glass fiber, and PET(polyethylene terephthalate) on reinforced concrete flexural members. Variables of theoretical analysis are types of strengthening materials, material properties and amount of strengthening materials. A virtual flexural member without FRP sheets was created as a control specimen to understand the structural behavior of the non-strengthened specimen in terms of elastic and ultimate cross section. In total, 11 specimens including one non-strengthened and ten strengthened specimens were investigated. Various variables such as types of strengthening, strengthening properties, and amount of strengthening were studied to compare the behavior of the control specimen with those of strengthened specimens with regard to moment-curvature relationship. Results of theoretical analysis showed that the moment capacity of strengthened specimens was superior to that of the control specimen. However, the control specimen indicated the best ductility among all the specimens. As the amount of strengthening increased, flexural performance was improved. Furthermore, the results indicated that the ductile effect of members was affected by the ultimate strain of FRP sheets. The strengthening effect on the damaged member was similar to that on the non-damaged one since there was less than 10% difference in terms of flexural strength and ductility. Therefore, even if a damaged member is treated as non-damaged for analysis there is probably no noticeable difference.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.83-92
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• 2017

This paper deals with numerical analysis of behavior of curved mechanically stabilized earth(MSE) walls with geosynthetics reinforcement. Unlike typical concrete retaining walls, MSE wall enables securing stability of higher walls without being constrained by backfill height and is currently and widely used to create spaces for industrial and residential complexes. The design of MSE walls is carried out by checking external stability, similarly to the external checks of conventional retaining wall. In addition, internal stability check is mandatory. Typical stability check based on numerical analysis is done assuming 2-dimensional condition (plane strain condition). However, according to the former studies of 3-dimensional MSE wall, the most weakest part of a curved geosynthetic MSE wall is reported as the convex location, which is also identified from the studies of the laboratory model tests and field monitoring. In order to understand the behaviour of the convex location of the MSE wall, 2-dimensional analysis clearly reveals its limitation. Furthermore, laboratory model tests and field monitoring also have restriction in recognizing their behaviour and failure mechanism. In this study, 3-dimensional numerical analysis was performed to figure out the behaviour of the curved part of the geosynthetic reinforced wall, and the results of the straight-line and curved part in the numerical analysis were compared and analysed. In addition, the behaviour characteristics at each condition were compared by considering the overburden load and relative density of backfill.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.645-655
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• 2016

The purpose of this study is to analyze the roles and functions of NGO 's International Solidarity in the establishment of' DMZ World Peace Park ', the mechanism of operation, and the policy formation of NGO' s international solidarity. The establishment of the DMZ World Peace Park is a matter that can be achieved as a result of dialogue efforts between the two parties based on the agreement between the DPRK and the ROK government, but should take a more relaxed approach to the process issues in order to achieve such results And should be done in a long-term, step-by-step plan. In the process of realizing this, South Korea's own efforts alone are difficult, and it is necessary to seek various channels of dialogue with the international community so that North Korea can have dialogue negotiations. This will be the role of NGO, It should be noted. As a result, in order to establish 'DMZ World Peace Park', it is necessary to establish concrete road map of DMZ World Peace Park. In the first stage, it is necessary to organize and operate 'DMZ World Peace Park Promotion Committee' under the directorship of the President or Prime Minister, It is necessary to select candidates, to appeal to North Korea and to support the international community, and to participate voluntarily by the private sector. Phase 2 requires final settlement. Phase 3 will require a step-by-step road map, such as rapid construction of the Peace Park, expansion of peaceful use of the DMZ, and expansion of ecology, history and cultural tourism in the DMZ border area.

• Journal of Korean Academy of Nursing
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• v.23 no.3
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• pp.369-376
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• 1993

Since nursing has come of age both as a profession and as a scholarly discipline, there has been increasing concern with delineating its theory base. In 1978 Chinn and Jacobs asserted that “the development of theory is the most crucial task facing nursing today.” The basic building blocks of theories are concepts. Concept formation begins in infancy, for concepts help us to categorize and organize our environmental stimuli. Concepts help us to identify how our experiences are similar or equivalent by categorizing all the things that are alike about them. concepts can be primitive, concrete, or abstract. Concept Analysis is a strategy that examines the attributes or characteristics of a concept. It is a formal, linguistic exercise to determine those defining attributes. It encourages communication. Its basic purpose is to distinguish between the defining and irrelevant attributes of a concept similarities. It is a process of determining the differences between concepts and it is useful for several reasons. It is an excellent way to begin examining information in preparation for research or theory construction and results in an operational definition and a list of defining attributes and antecedents. It provides the scientist with an excellent beginning for a new tool, is an excellent way of evaluating an old one and is useful in evaluating existing instruments. The steps of concept analysis are : 1. Select a concept, 2. Determine the aims or purposes of the analysis, 3. Identify all uses of the concept that you can discover, 4. Determine the defining attributes, 5. Construct a model case, 6. Construct borderline, re-lated, contrary, invented, and illegitimate cases, 7. Identify antecedents and consequences, 8. Define empirical referents. In this paper, the concept selected for analysis was Love. The concept of love is of great interest to nursing because loving care is considered vital to the nursing care of patients. The aims of the concept analysis of love were to clarify the meaning of love, to develop an operational definition for it and to contribute to existing nursing theory. Love influences the quality of life which is the goal of nursing according to Parse in her Human Becoming Theory. Lived experiences are the entities for study in Parse's Research Methodology. Human caring, human understanding, and human becoming are the most important issues in lived experiences. In this research, dictionaries and literature from nursing philosophy and other human disciplines were used to identify the concept of love. As many different instances of the concept as could be found were examinned. The model case was a real life example of the use of the concept. Next borderline, related, invented, and contrary cases were constructed for the purpose of providing examples of “not the concept” and for promoting further understanding of the concept being discussed. The defining attributes of the concept of love were concern, responsibility, respect, understanding and dedication. Love was defined as showing concern and understanding. relating with mutual respect and dedicating oneself responsibly to others. Concept analysis is a highly creative activity and may add significant new information to a given area of interest. It is a strategy for developing a concept based on observation or other forms of empirical evidence. The purpose of concept analysis is to generate new ideas. It provides a method of examining data for new insights that contribute to theoretical development. This concept analysis suggests that a nurse’s love for patients is shown in the process of giving oneself in mutual relationships of responsibility and respect and in continuously providing understanding and quality human care for them.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.75-82
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• 2020

There have been often cases of collapse for geogrid reinforced soil (GRS) retaining wall. Hence, social interest in the reinforcement and restoration of the collapsed GRS wall is increasing day by day. However, there are only few researches. For this reason, a series of numerical analyses using the Plaxis 2D program was conducted in this study to analyze the suitable reinforcement methods that can be applied on the existing damaged GRS wall caused by overturning of the modular blocks facing and the surface settlement at the backfill as the results from the design failure. The restoration plan used in this study is composed of two cases: (Case 1) soil nailing reinforcement and reinforced concrete (RC) wall facing construction on the existing damaged GRS wall; and (Case 2) removal of the entire damaged GRS wall and then reconstruction. The results on the internal stability of the GRS wall show that Case 1 obtained a greater safety factor than Case 2 for tensile force while Case 2 had a greater safety factor than Case 1 for pullout failures. Case 1 was found to be more stable than Case 2 in terms of the global slope safety by shear strength reduction method and the external deformation behavior by numerical analysis. In this study, the existing damaged GRS wall which was reinforced using Case 1 method shows more stable external behavior.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.83-91
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• 2020

In this study, the characteristics of support behavior according to the change of ground condition of the cast-in-place pile and the large Caisson foundation, which are increasingly used as foundations of large structures and bridges. the allowable bearing capacity calculated using the yield load analysis method was analyzed to calculate similar allowable bearing capacity for each method. In addition, the allowable bearing capacity calculated by the ultimate load analysis method was found to have a large difference in bearing capacity for each method. Through this point, it can be usefully used as an empirical formula for evaluating the settlement characteristics of piles in future design and construction. In addition, as a result of examining the ground force distribution during sedimentation of large caissons, the section of the weathered rock layer showed almost constant ground force distribution as ground forces decreased after yield occurred at the base corner. And in the bed rock layer section, the foundation's center was transformed into a ground force in the form of a convex downward due to an increase in the ground resistance of the central part. Using these results, the theory previously presented by Fang (1991) and Kőgler (1936) was proved.