• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.73-88
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• 2007

The goal of this research is to develop and apply the generalized regression neural networks model(GRNNM) embedding genetic algorithm(GA) for the estimation and calculation of the pan evaporation(PE), which is missed or ungaged and of the alfalfa reference evapotranspiration ($ET_r$), which is not measured in South Korea. Since the observed data of the alfalfa 37. using Iysimeter have not been measured for a long time in South Korea, the Penman-Monteith(PM) method is used to estimate the observed alfalfa $ET_r$. In this research, we develop the COMBINE-GRNNM-GA(Type-1) model for the calculation of the optimal PE and the alfalfa $ET_r$. The suggested COMBINE-GRNNM-GA(Type-1) model is evaluated through training, testing, and reproduction processes. The COMBINE-GRNNM-GA(Type-1) model can evaluate the suggested climatic variables and also construct the reliable data for the PE and the alfalfa $ET_r$. We think that the constructive data could be used as the reference data for irrigation and drainage networks system in South Korea.

• Korean Journal of Social Welfare
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• v.51
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• pp.211-228
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• 2002

Despite the importance of the needs assessment activities and the necessity of the systematical investigation on the features of the needs assessment in the social service agencies, it has been observed that the recent NA studies have ignored an important study area of NA, the utilization of needs assessment results in social service agencies. Therefore, this study was undertaken to investigate salient features of the utilization of community needs assessment results, particularly, in the social welfare centers located in Seoul city. A questionnaire was constructed with seven parts, including a dependent variable and 6 independent variables, and 67 questionnaires were collected from 90 agencies during two months. As the result of the descriptive analyses, the five noticeable features were found; (1) the needs assessment results in the agencies was not highly utilized; (2) the attitude on the NA activities was not highly positive because the responders thought that NA activities require too much time from agency staff; (3) agency staff was more actively involved in the NA process than agency directors; (4) the responders thought that quality of NA influences on the utilization of NA; (5) the respondents were confident in carrying out NA although they did not have many opportunities to learn the technical skills of NA research. Multiple regressions were applied to analyze the relationship between independent variables and three kind of dependent variables - conceptual utilization, instrumental utilization, total utilization. The result showed that the conceptual utilization was critically influenced by social workers' confidence on NA, attitude on NA, and directors' involvement in NA. The institutional utilization was influenced by the directors' involvement. The total utilization was influenced by social workers' attitude on NA, confidence on NA, and directors's involvement. Major findings were discussed and several suggestions were made for future research and improvement of the utilization of needs assessment result in social welfare centers.

• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.440-445
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• 2005

The limitation of measurement accuracy and reliability of autostigmatic null lens system are studied for the cases of using inter-distance of null lenses as the adjustment factor of alignment and fixing the distance by mounting. If we investigate the first case, the wavefront aberration of null lens system is compensated by the adjustment process even though the shape of aspherical surface is not properly fabricated. As the result, it brings about the problem of measurement reliability. However, for the fixing process by mounting null lenses, it doesn't cause the reliability problem because the wavefront aberration of null lens system is not compensated. Further, the fixing process shows nearly same result in measurement accuracy to the adjustment process, that is, $0.0316{\lambda}$ vs. $0.0326{\lambda}$. So, we can conclude the setup for autostigmatic null lens system must be constituted by means of the fixing process. Meanwhile, we introduce and define the alignment aperture on aspheircal mirror, which can be approximated as spherical zone for alignment of null lens system, and besides, we calculate the required fabrication accuracy of the zone for the necessary measurement accuracy.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.4
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• pp.91-100
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• 2019

Many university students try to start up a lot because of career uncertainty, and this study reflected this environmental situation. The subject of the study is the degree to which subjective norms of university students affect the start-up intention. In addition, we looked at the mediated effects of self-efficiency and the moderated effects of security competence. To verify the hypothesis of the study, 201 university students in Seoul were asked about the relevant variables. And based on prior theory, hypotheses and questionnaires were made. In addition, the validity, reliability and correlation analysis of each variable were conducted. Multiple regression analysis was used for hypothesis analysis. As a result, subjective norms have a positive effect on the start-up intention. Next, self-efficiency was found to be mediating the relationship between subjective norms and start-up intentions. Finally, when subjective norms affect the start-up intention, security competence showed negative moderate effect. The implications of this study are as follows: First, a positive perception of start-up by those around them is needed when it comes to raising the intention of starting a business. This positive perception also affects the confidence and sense of challenge in start-up and affects their start-up intention. However, if career anchor prefer stable employment for the organization, it can be seen that they negatively affect the start-up intention.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.88-104
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• 2009

Changes in a society and visual media has a tight relationship. Photography represented the last 20th century in the visual media; while the 21st century we live in is represented by moving image(video). The change of visual media also brought changes to the archaeological recordings. As information is gathered from the field work in archaeology, it seems that use of video recording, a reliable way of collecting and recording data, will increase. The process of archaeological excavations can be considered as a contents itself. Also, video recording has many advantages when recording environmental surrounding of the sites and artifacts, for the reservation of the scenery, and as recorded heritage of the humankind. Video recording can be a tool of conversion to public archaeology to devote to its social and academic roles. Considering all of the above, studying ways to record and preserve visual materials is essential in the field of archaeology and we should be prepared for it. We strongly propose reinstatement of the visual archaeology, which should be studied in archaeological perspective. The direction of the study of visual archaeology can be summarized into two. First is the study on the video recording during field work and the archive of video recordings. Second is the study on the media as the tool of communication. More detailed and organized research should be considered in depth in the archaeological theory and methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.272-278
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• 2018

Traffic volume has been greatly increasing due to urban development and the improvement of living standards, and many complaints are being raised due to the increasing road noise. As a countermeasure against these problems, highly soundproof walls are installed on the sides of roads. However, the ability to bear wind loads is a major design requirement for soundproof walls, which contributes to the exponential increases in construction costs and restricts the height of the walls. The aim of this study is to improve the performance of soundproof walls and to dramatically reduce wind loads while maintaining excellent price competitiveness. Based on Helmholz's resonator theory, a new concept is proposed for a ventilation-type soundproofing plate that can pass through a fluid like air and reduce noise. A full-scale metal soundproofing plate was produced to satisfy the quality standards of highways by conducting a sound-pressure transmission-loss test, wind tunnel test, and material quality test. To verify the reliability, the wall was manufactured and installed, and the sound insulation effect was examined by measuring the noise over time. In the future, ventilated soundproof walls on roads could create a pleasant living environment due to the high noise-insulation effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.573-582
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• 2021

In this study, a series of processes for evaluating the effective protection against barriers that should be equipped in institutions that perform reliability tests on high-risk ammunition, such as high-explosive ammunition, were introduced. The impact that high-explosive bombs can have on personnel includes damage to the eardrum and lungs caused by explosion overpressure and penetrating wounds that can be received by fragments generated simultaneously with the explosion. Therefore, a high-explosive with COMP B explosives as its contents were set up, and an explosion protection theory investigation to calculate the degree of damage, numerical calculations and simulations were performed to verify the protection power. A numerical calculation revealed the maximum explosion overpressure on the protective wall when the high-explosive exploded and the penetration force of the fragment against a 50 mm-thick protective wall to be 77.74 kPa and 41.34 mm, respectively. In the simulation verification using AUTODYN, the maximum explosion overpressures affecting the firewall and personnel were 56.68 kPa and 18.175 kPa, respectively, and the penetration of fragments was 35.56 mm. This figure is lower than the human damage limit, and it was judged that the protective power of the barrier would be effective.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.639-645
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• 2020

Among the components of redox flow battery (RFB), the electrode serves as a diffusion layer of an electrolyte and a path for electrons and also is a major component that directly affects the RFB performance. In this paper, chloric/sulfuric mixed acidwas used as a supporting electrolyte in RFB system with Fe2+/Fe3+ and V2+/V3+ as redox couple. The optimum electrode and activation temperature were suggested by comparing the capacity, coulombic efficiency and energy efficiency according to the electrode type and activation temperature. In the RFB single cell evaluation using 5 types of carbon electrodes used in the experiments, all of them showed close to the theoretical capacity to retain the reliability of the evaluation results. GFD4EA showed relatively excellent energy efficiency and charge/discharge capacity. In order to investigate the electrochemical performance according to the activation temperature, GFD4EA electrode was activated by heat treatment at different temperatures of 400, 450, 500, 600 and 700 ℃ under an air atmosphere. Changes in physical properties before and after the activation were observed using electrode mass retention, scanning electron microscope (SEM), XPS analysis, and electrochemical performance was compared by conducting RFB single evaluation using electrodes activated at each temperature given above.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.187-197
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• 2021

Clay mineral content of weathered zone is a key parameter for landslide studies. Electrical resistivity tomography is usually performed to delineate the geometry of complex landslides and to identify the sliding surface. In clay-bearing weathered zone, parallel resistivity Archie equation is employed to investigate the effect of conductivity added (resistivity reduced) by clay minerals of kaolinite and montmorillonite, which is dependent on their specific surface area and cation exchange capacities (CEC). A decrease of overall resistivity and apparent formation factor is observed with increasing pore-water resistivity, significantly in montmorillonite. Formation factor is found decreased with increasing porosity and decreasing cementation factor. Parallel Archie equation was applied to the electrical resistivity data from the test area (Sinjindo-ri, Taean-gun, Chungcheongnam-do, Korea) which experienced land creeping in the year of 2014. A panel test with varying clay-mineral contents provides the best fit section when the theoretical section constructed with the assumed contents approaches the field section, from which the clay-mineral content of the weathered zone is estimated to be approximately 10%. Resistivity interpretation schemes including the clay mineral contents for land creeping studies explored in this paper can be challenged more when porosity, saturation, and pore-water resistivity are provided and they are included in the numerical resistivity modeling.

• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.91-107
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• 2020

The purpose of this study is to explore quantitatively the success factors of YouTube's music cover channel. Along the process, constructing and testing the measurement for music cover channel's characteristics. The research constructed the measurement items based on results of qualitative studies. To perform the purposes the study suggest a research model which integrated the Post Acceptance Model with five music cover channel's characteristics based on the recent case studies. The five characteristics were contents, video, creator, interactivity, and publicity. The characteristics were integrated with Post Acceptance Model. After testing reliability and validity the research model was revised then, the research hypothesis was tested. The research results show: first, it was found that the content characteristics did not meet the expected value of users. Second, among the five factors of channel characteristics presented in creator's characteristics have the largest effect on user's value perception Third, in the factor analysis process, the content factor and the video were loaded on the same factor thus integrated as one factor. Fourth, satisfaction and intention for continual usage were also loaded on the same factor thus integrated as one factor. The research results suggest that music cover channel operators need to enhance the creator's attraction, communication with user, and publicity in various ways.