• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.9-18
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• 2009

This paper introduces the application of DE (Differential Evolutionary) method for the estimation of tensile force of the externally prestressed tendon. The proposed technique, a SI (System Identification) method using the DE algorithm, can make global solution search possible as opposed to classical gradient-based optimization techniques. The numerical tests show that the proposed technique employing DE algorithm is a useful method which can detect the effective nominal diameters as well as estimate the exact tensile forces of the externally prestressed tendon with an estimation error less than 1% although there is no a priori information about the identification variables. In addition, the validity of the proposed technique is experimentally proved using a scale-down model test considering the serviceability state condition without and with the loss of the prestressed force. The test results prove that the technique is a feasible and effective method that can not only estimate the exact tensile forces and detect the effective nominal diameters but also inspect the damping properties of test model irrespective of the loss of the prestressed force. The 2% error of the estimated effective nominal diameter is due to the difference between the real tendon diameter with a wired section and the FE model diameter with a full-section. Finally, The accuracy and superiority of the proposed technique using the DE algorithm are verified through the comparative study with the existing theories.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.71-80
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• 2010

Bridge deck is directly influenced by environment and vehicle load, it is easily damaged so that it requires an appropriate repair and retrofit. Therefore, developing a bridge deck with high durability is necessary in order to minimize the maintenance of bridge deck and use it to its design life. In this study, static test was carried out to evaluate a fatigue capacity of steel-concrete composite deck, which was newly developed by supplementing problems of existing reinforced concrete deck. Based on results from the static test, fatigue load was decided, and fatigue test was conducted under the constant amplitude repeated load. From the fatigue tests, the S-N curve regarding principle structural details of composite deck was made, and characteristics of fatigue behavior was estimated by comparing and evaluating it with fatigue design criteria. In addition, fatigue design guideline was presented. As a result, it is found that each structural details of composite deck proposed by this study, such as upper flange of corrugated steel plate and middle section of it, shear connector and lower flange of corrugated steel plate, is satisfying the fatigue strength.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.259-266
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• 2009

The steel pipe of steel-concrete composite piles increases the pile strength and induces the ductile failure by constraining the deformation of the inner concrete. In this research, the numerical models and the related input parameters were analyzed to simulate the axial load-movement relations, which were obtained from the compression loading tests for the cylindrical specimens of the steel pipe, the concrete, and the steel-concrete composite. As the results, the behavior of the steel pipe was simulated by the von-Mises model and that of the concrete by the strain-softening model, which decreases cohesion and dilation angles as the function of plastic strains. In addition, the reinforcing bars in the concrete were simulated by applying the yielding moment and decreasing the sectional area of the bars. The applied numerical models properly simulated the yielding behavior and the reinforcement effect of the steel-concrete composite piles. The parametric study for the real-size piles showed that the material strength of the steel-concrete composite pile increased about 10% for the axial loading and about 20~45% for the horizontal loading due to the reinforcement effect by the surrounding steel pipe pile.

• 한국노년학
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• v.32 no.2
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• pp.559-576
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• 2012

This research aims to address the effect of Guided Autobiography(GAB) on ego-integrity, depression and life-satisfaction in the elderly and to investigate psychological changes and experiences on the senior subject. 20 subjects participated weekly autobiography writing sessions in a senior academy in the S city for 13 weeks. In this research, we carried out examination on ego-integrity, depression test, and life-satisfaction survey were performed before and after the writing sessions for a quantitative analysis, which was later investigated through a 'corresponding sample T-test'. Based on the results of the above mentioned tests, the qualitative analysis was conducted through an individual sessions with 5 selected participants. The results of this research are summarized as following. First, ego-integrity showed satisfactorily meaningful difference between pre- and post-GAB writing. The participants recollected the past repent and revisited unresolved issues in their lives. The subjects were able to accept these past misdemeanors and appreciate their lives. GAB indeed helped improving ego-integrity. Second, the hypothesis that GAB writing will help decrease depression was accepted. 2-page weekly writing assignments enabled the participants think of joyful moments in their past, and showed decrease the symptoms of depression. Third, this study revealed that GAB writing improved life- satisfaction. The participants learned to express gratitude and peace in their mind. The happy feeling and optimistic thoughts enhanced their satisfaction of life in turn. In addition, it turned out that the effects of GAB were more drastic in group sessions than in individual writings. Interpersonal interactions in group sessions encouraged the exchange of positive feedback, thereby helping them reflect themselves positively.

• Korean Journal of Health Psychology
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• v.16 no.3
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• pp.557-575
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• 2011

This study tried to examine the characteristics of attention deficits in patients with Obstructive Sleep Apenea(OSA) with different age levels, and to examine which indices of polysomnograms might be related to the indices of attention deficits in OSAs. Two age-level groups and a normal control group were subjected to two computerized attention tests, including a continuous performance test(CPT) and a change blindness task(CBT). In addition, the three groups were subjected to a Polysomnography to extract several sub-indicators of polysomnogram, and an Epworth Sleepiness Scale which measures subjective sleepiness. As results, the OSAs showed significantly more omission and commission errors in CPT, and they showed lower accuracy in CBT compared to the normal group. The results of a correlational analysis showed that attention deficits in OSA are significantly correlated with arterial oxygen saturation among sub-indicators of polysomnograms. In conclusion, OSAs seems to be less attentive, having difficulties in response inhibition, and having deficiencies in noticing important environmental changes. Age seems to make these deficiencies even worse. Especially, the relationship between attention deficiency and hypoxia which could cause irreversible cerebrum damage has an implication in cognitive impairment prevention through early treatment.

• Educational Technology International
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• v.6 no.2
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• pp.23-41
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• 2005

One of the main factors that determine the quality of instruction is the teaching ability of the instructor administering the class. To evaluate teaching ability, methods such as peer review, student feedback, and teaching portfolio can be used. Among these, because feedback from the students is directly associated with how well the students feel they have learned, it is essential to improving instruction and teaching ability. The principal aim of instruction evaluation lies in the evaluation of instructor's qualification and the improvement of instruction quality by enhancing professionalism. However, the mandatory instruction evaluations currently being carried out at the term's end in universities today have limitations in improving instruction in terms of its evaluation items and times. To improve the quality of instruction and raise teaching abilities, instruction evaluations should not stop at simply being carried out but also be utilized as useful data for students and teachers. In other words, they need to be used to develop teaching and improve instruction for teachers, and consequently, should also exert a positive influence on students' scholastic achievements and learning ability. The most important thing in evaluation is the acquisition of accurate information and how to utilize it to improve instruction. The online instruction diagnosis item pool is a more realistic feedback device developed to improve instruction quality. The instruction diagnosis item pool is a cafeteria-like collection of hundreds of feedback questions provided to enable instructors to diagnose their instruction through self-diagnosis or students' feedback, and the instructors can directly select the questions that are appropriate to the special characteristics of their instruction voluntarily make use of them whenever they are needed. The current study, in order to find out if the online instruction diagnosis item pool is truly useful in reforming and improving instruction, conducted pre and post tests using 256 undergraduate students from Y university as subjects, and studied the effects of student feedback on instructions. Results showed that the implementation of instruction diagnosis improved students' responsibility regarding their classes, and students had positive opinions regarding the usefulness of online instruction diagnosis item pool in instruction evaluation. Also, after instruction diagnosis, analyzing the results through consultations with education development specialists, and then establishing and carrying out instruction reforms were shown to be more effective. In order to utilize the instruction diagnostic system more effectively, from planning the execution of instruction diagnosis to analyzing the results, consulting, and deciding how those results could be utilized to instruction, a systematic strategy is needed. In addition, professors and students need to develop a more active sense of ownership in order to elevate the level of their instruction.

• Educational Technology International
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• v.8 no.1
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• pp.17-39
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• 2007

The purpose of this study was to identify the relationships among organizational commitment, job satisfaction, and learning organization culture. This study was conducted in five sub-organizations of one Korean conglomerate company. One thousand employees were randomly and proportionately selected, with 669 useable cases obtained, for a response rate of 67%. The organizational commitment instrument used from the "affective, continuance, and normative commitment" scale (ACNCS) of Allen and Meyer (1990). The "Dimensions of Learning Organization Questionnaire" of Watkins and Marsick (1997) was used to measure learning organization culture. The short form MSQ (Minnesota Satisfaction Questionnaire), developed by Weiss, Dawis, England, and Lofquist (1967), was the third instrument used. Descriptive statistics, correlational statistics, and inferential statistics (ANOVA and t-tests) were used. Organizational commitment (except for continuance) is moderately and positively related to job satisfaction and moderately and positively related to learning organization culture. In addition, learning organization culture is weakly to moderately and positively related to job satisfaction. No differences by age were found. Four-year college graduates are more likely to have higher creating continuous learning opportunities in learning organization culture than graduate school degree holders. Males are likely to have higher affective and continuance organizational commitment than females. Employees working in R&D, Engineering, and Manufacturing (REM) are likely to have higher continuance organizational commitment than do other types of jobs. Employees are more likely to have higher learning organization culture and job satisfaction than assistant managers. Assistant managers have higher continuance organizational commitment than managers. Managers generally have higher organizational commitment, learning organization culture, job satisfaction than assistant managers. They also have higher learning organization culture than employees. Employees who had worked for less than four years in their current job and organization have higher promoting inquiry and dialogue in learning organization culture than those who have worked for ten years or more. Employees in the insurance organization have higher affective organizational commitment, learning organization culture, and job satisfaction than those of the other organizations. Finally, employees of the electronic company have higher continuance organizational commitment in learning organization culture than those of other companies. In summary, this research enables CEOs and HRD and HRM practitioners to view organizational commitment, learning organization culture, and job satisfaction as important variables in exploring diverse ranges of topics related to the workplace. And then, they can diversely apply their management, interventions and practices to fit these diverse characteristics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.365-373
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• 2023

Since the lips are a representative facial part that can express human attraction, aesthetic interest in them has always existed in human history. However, as lips age, they tend to form wrinkles, become thinner, and lose their volume. To counteract this phenomenon, medical procedures such as fillers or fat transplantation have been suggested. In this study, we verified that the one of main effective material complex of L G H&H L IPCERIN^®, combination of cedrol, a sesquiterpene found in cedarwood, and three peptides (acetyl hexapeptide-8, acetyl tetrapeptide-9, and desamidocollagen) could ameliorate the photo-aging and reduce the wrinkles through in vitro experiments. The possibility of improving collagen and elastin expression in skin fibroblasts and reducing MMP expression under photoaging conditions was verified. In addition, it was confirmed that the amount of fat tissue in the lips can be increased by promoting adipose stem cell differentiation and increasing the amount of fat produced in the in vitro adipose stem cell differentiation experiment. Two weeks of human application tests confirmed that a combination of cedrol and peptides can improve the wrinkles, texture, elasticity, and volume of the lips. This study verified that the combination of cedrol and three peptides can be used as effective cosmetic materials to decrease the various signs of aging in the lips.

• Korean Journal of Culture and Social Issue
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• v.14 no.1_spc
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• pp.63-109
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• 2008

This article examines psychological factors that contribute to educational achievement of Korean adolescents. By reviewing empirical research, three core areas are outlined. First, positive and negative roles that Korean society play on academic achievement are analyzed. Compared to other countries, Korean society places a high premium, pressure an investment on educational achievement. This has contributed to the rapid economic growth and development, but at the same time it has created numerous social problems. Second, psychological and relational dynamics of investing in and achieving success in education are delineated. Through indigenous psychological analysis, the role parents play in motivating and regulating their children to succeed academically is reviewed. In addition, the role of teachers and friends and the coordinated efforts of Korean society are outlined. Third, future directions and transformations in education that are needed in Korean society are discussed. Although Korean adolescents are high achievers in high school, this is not the case at the university level. Since Korean students are interested in entering a prestigious university, they have developed skills in doing well in standardized tests. Educational reforms need to take into consideration individuals' personal interests, skills and creativity to ensure that the knowledge that they acquired can be used to further their career and improve their subjective well-being. Educational transformation does not imply simply adopting Western models, but developing indigenous models that can maximize human and cultural potential and stimulate curiosity, diversity and creativity that are necessary in the global era.

• Journal of Korean Elementary Science Education
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• v.42 no.4
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• pp.605-617
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• 2023

In this study, a STEAM program emphasizing the engineering design process was developed and applied to investigate its effects on the creative engineering problem-solving proficiency and self-directed learning ability of elementary school students. In addition, the study compared and analyzed differences according to gender. The program was conducted across five sessions targeting 141 students in the fourth grade in an elementary school in the Gyeongin area. The study measured the creative engineering problem-solving disposition and self-directed learning ability of the students before and after the STEAM program. It also administered satisfaction and perception tests. The result confirmed that the STEAM program that emphasizes the engineering design process is effective in improving the creative engineering problem-solving propensity and self-directed learning ability of elementary school students, particularly female ones. Analyzing differences in changes based on gender, the study pinpointed significant improvements among female students in all factors except for the subfactor communication and collaboration within tendencies toward creative engineering problem-solving. For male students, the study observed significant effects in the factors engineering design and communication and collaboration. Lastly, the study discussed the educational implications of the findings.