• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1275-1282
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• 2012

Helicopter rotor systems are dynamically loaded structures with many composite components such as the main and the tail rotor blades. The fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. The safe-life methodology has generally been used in the helicopter industry to substantiate dynamically loaded composite components. However, it cannot be used to evaluate the strength reducing effects of flaws and defects that may occur during manufacturing and operational usage. The damage tolerance methodology provides a proper means to overcome this shortcoming; however, it is difficult to economically apply it to every composite component. The flaw tolerant methodology is an equivalent option to the damage tolerance methodology for civil and military rotorcraft. In this study, the flaw tolerant safe-life evaluation is described and illustrated by means of successful application to substantiate the retirement time of composite rotor blades.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.1 no.1
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• pp.53-70
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• 2006

This study aims to provide policy suggestions on how to implement the process of empowerment, by investigating the conditions that hinder the process and the attitude of the KBS employees. For the cross-sectional study, this thesis examined the domestic and international references, conducted a survey of KBS employees, personal interviews and made direct observations. Approximately 1,200 copies of the questionnaire were distributed and 474 were completed and returned. The analysis used SPSS 12.0 software to process the data collected from 460 respondents. The survey findings showed a decrease of 24.2%p in the number of responses expressing negative views of the team structure and a decrease of 1.29%p in the number of positive responses. The findings indicated a positive transformation illustrating employees' improved understanding and approval of the team structure. However, KBS must address the issue on an ongoing basis. It has been proven that the employee empowerment increases the productivity of the individual and the group. In order to boost the level of empowerment, the management must exercise new, innovative leadership and build trust between the managers and the employees first. Additional workload as a result of shirking at work places was prevalent throughout all divisions and ranks, according to the survey data. This outcome leads to the conclusion that the workload is not evenly distributed or shared. And the data also showed the employees do not trust the assessment and rewards system. More attention and consideration must be paid to the team size and job allocation in order to address this matter; the present assessment and rewards system need to be complemented. The type of leadership varies depending on the characteristics of the organization's structure and employees' disposition. KBS must develop and reform its own management, leadership style to suit the characteristics of individual teams. Finally, for a soft-landing of KBS team structure, in-house training and education are necessary.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.722-729
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• 2010

Prediction problems are widely used in medical domains. For example, computer aided diagnosis or prognosis is a key component in a CDSS (Clinical Decision Support System). SVMs with nonlinear kernels like RBF kernels, have shown superior accuracy in prediction problems. However, they are not preferred by physicians for medical prediction problems because nonlinear SVMs are difficult to visualize, thus it is hard to provide intuitive interpretation of prediction results to physicians. Nomogram was proposed to visualize SVM classification models. However, it cannot visualize nonlinear SVM models. Localized Radial Basis Function (LRBF) was proposed which shows comparable accuracy as the RBF kernel while the LRBF kernel is easier to interpret since it can be linearly decomposed. This paper presents a new tool named VRIFA, which integrates the nomogram and LRBF kernel to provide users with an interactive visualization of nonlinear SVM models, VRIFA visualizes the internal structure of nonlinear SVM models showing the effect of each feature, the magnitude of the effect, and the change at the prediction output. VRIFA also performs nomogram-based feature selection while training a model in order to remove noise or redundant features and improve the prediction accuracy. The area under the ROC curve (AUC) can be used to evaluate the prediction result when the data set is highly imbalanced. The tool can be used by biomedical researchers for computer-aided diagnosis and risk factor analysis for diseases.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.4
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• pp.83-98
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• 2018

The purpose of this study was to investigate how college students perceive social economics as a young age, This study was conducted three times at intervals of two weeks with five college students who are engaged in SEN club activities in Seoul, Korea. To achieve the purpose of the study, a participatory practice research technique called Photovoice qualitative research method was used. Participants in the main topic of social economy were selected by the participants as 'Social economy is', 'SEN for me' and 'My future career'. Respectively. The results of the study are as follows. First, the research students of the study group have taken pictures of the social economy in terms of 'diversity', 'consideration', 'cooperation', 'cooperation', 'help' and 'conflict of interest'. Second, the students participating in the research semantics mean the pictures taken with 'enjoyment', 'happiness', 'hope', 'community', 'sense of belonging' and 'affection'. Third, the college students who participated in the study have taken the meaning of the pictures taken in the future, such as 'clumsiness', 'what they want to do', 'career towards the public'. Finally, in-depth interviews on the career paths of graduates reveal that it is not easy to advance into a social economic organization. The results of this study provide the practical guidelines where the curriculums needed for the entrepreneurship education at graduate schools by suggesting consistency for the systematic and comprehensive curriculum design. It was reflected the survey result from the graduate students taking the entrepreneurship subjects. Therefore, it will contribute the foundation of the present curriculum of Entrepreneurial Graduate School.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.576-584
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• 2020

The extruder screw material is mainly SKD11, but the recent development of synthetic resins have increased the occurrence of chemical corrosion and wear. To solve this issue, high chromium cast iron is needed because of its good abrasion resistance and corrosion resistance, but its use is avoided because of its poor machinability. In this study, to improve the machinability of high chrome cast iron, 0, 0.5, 1.0, 1.5% of nickel, which has excellent workability, was added to high chromium cast iron with a composition of Fe-23Cr-2.5C-1.2Si-1.08Mn-0.48Mo-0.3V, and annealed after casting. Subsequently, the effect of nickel on the machinability and corrosion resistance was analyzed using a turning test and coin polarization test, and compared with SKD11. After casting using a high-frequency vacuum induction furnace, the annealing treatment was performed at 750 ℃ for five hours and then reheated at 1100 ℃ for five hours. A turning test after annealing at 750 ℃ showed that the machinability was improved remarkably when the nickel content was over 1.0%. In the potentiodynamic polarization test in a 5% NaCl solution, the corrosion resistance decreased with increasing nickel content in the as-cast and annealing treatment. On the other hand, after reheating, the corrosion resistance was best with a 1.5% nickel content.

• Communications of Mathematical Education
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• v.23 no.2
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• pp.255-277
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• 2009

Currently Science and technology are changing so fast these days, educating competent and creative person, majoring in natural sciences, including mathematics., becoming more and more important. But, in Korea, there are many problems in high school and university education program, so performance level in mathematics is decreasing and avoiding mathematics and natural sciences is increasing. Naturally the numbers of science oritented students in high school are decreasing and ability in mathematics, in particular calculus, is decreasing. Hence, the above situation leads to a reduction of scientific manpower. In this point of a view, we analyse the situation of the downturn of the ability of the science, especially calculus, among engineering majored freshmen. We also study many data reported by Ministry of Education and Science, Korea and scholar societies. From this study we conclude that the essential rerasons for the above situations are curriculum and the system of the entrance examination of the university, and we give suggestions for solutions of such a situation.

• Journal of Gifted/Talented Education
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• v.25 no.3
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• pp.363-380
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• 2015

The convergent education such as STEAM education has been implemented in the gifted education institutions in order to resolve the crisis of science and engineering fields caused by the science and engineering avoidance of excellent talents. The purpose of this study was to investigate awareness about science, mathematics and technology/ engineering fields of science gifted students. The subjects were 86 middle school science gifted students at the Science Institute for Gifted Students of a university located in metropolitan city in Korea. The data were collected from the survey that consists of 97 questions in 3 categories. The results were follows: First, the gifted students were aware that science was more interesting than mathematics or technology/engineering. Second, science rated highest in career choice. Third, they were aware that the scientists were more interesting, more imagination, less accuracy and less considering than the mathematicians and the engineers. In addition they responded that the mathematicians were smarter than the scientists and the engineers, and the engineers were more diligent than the scientists and the mathematicians. Finally, the result of the correlational analysis indicated that there were strong correlations between science and mathematics, and between science and technology/engineering. It was recommended that the consolidation of the convergent gifted education, the necessity of systemic career education, and the study of correlation between mathematics and technology/engineering.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.21-30
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• 2014

Waste landfill site which is the facility usually rejected by communities is generally perceived as one of the serious social problems. It causes serious conflicts between interested parties from the beginning of the site selection process and produces various difficulties throughout the installation process. This study suggests the systematization and standardization of the landfill site selection process to reduce those problems and to objectify the process. The study process and results are as follows. First, the landfill site selection process was divided into 4 general phases rather than more specific fragmented phases and the requirements for each phase were suggested accordingly. This can make the process clearly organized and bring the standardization of the process by increasing the applicability of each phase for various situations. Second, the utilization of GIS(Geographic Information System) and PAPRIKA (Potentially All Pairwise RanKings of all possible Alternatives) among the various MCDA(Multi-Criteria Decision Analysis) methods was suggested as the objective and scientific method. Third, the hypothetical case study on the landfill site selection process of Cheongju city was conducted based on the information above and the results show the practicability and objectivity of the newly defined landfill site selection process in this study.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.471-478
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• 2011

The ginseng stem fungus gnat, Phytosciara procera, overwintered in old stems and roots of ginseng as a larvae from late September to early May in next year. In the late Spring they become pupa then emerged. Therefore, the first control period has to be set between late May and early June. It is a same period of elimination of ginseng flower stalks. Two or three times pest control might be needed per month for controlling adult of P. procera. Otherwise, the overwintered form as larva in old stem by removal of old stems of ginseng, the population of first generation of P. procera adults could be reduced. However, it seemed that the removal of old stems was not necessarily correlated with the population of P. procera adults in the next generation. Three kinds of environmental-friendly control agents that were mainly contained sophora extract, showed the highly insecticidal activities against larva of P. procera. Among them, one agent containing sophora extract and paraffin oil showed an ovicidal action as well as oviposition repellency.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.191-202
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• 1985

As the result of a significant improvement in the economic situation and development of scientific techniques in Korea during the last 20 years, the life expectancy of the Korean people has lengthened considerably and as a result the number of old aged people has markedly increased. Such an increase of the number of aged people brought about many problems. Authors would like to take a medical look at the "Problem of old aged people" presently facing us in Korea. Currently the number of people over 65 has increased rapidly and is 1,620,000, 4% of total population. But it is still much lower than 8.9% in Japan, 10.7% in U.S.A., and 14.9% in the United Kingdom. Over 25% of these aged people were found to have at least more than one disease which requires medical care. Diseases occur in the circulatory system, 30.9%, respiratory system, 17.1%, digestive system 8.6%, mental disorders, 8.4%, malignant neoplasms, 7.0%. About 51% of the aged over 65 are under medical security benefit, mostly with partial coverage plan. Their clinic visit rate was very low (2.0% in 1981), which might be due to financial reasons. Since diseases affecting the aged progress chronically, early detection and long term care are utter most important. However there is almost no special facility, long term care center or geriatric specialist. For proper management of medical problems in the growing population of the Korean eldery expansion of medical security coverage, greater number of specialized facilities, education of geriatric special manpower and efficient operating system should be established.