• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.201-208
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• 2017

Recently, the installation of photovoltaic(PV) systems has been increasing due to the worldwide interest in eco-friendly and abundant solar energy. On the other hand, a PV system has approximately 25% power loss while the energy generated from solar cells is transformed to the power coupling point through a power conversion system (DC/AC). If the output voltage of a string in the PV system is lower than the operating range of the inverter when a part of module in the string has a shadow due to weather conditions, the string is not synchronized and the whole efficiency of output power in a PV system may be reduced significantly. Therefore, to overcome this problem, this paper proposes a novel control method to compensate for the lower voltage by introducing a DC/DC voltage regulator for each string in a PV system, which adopts a concept for MPPT (Maximum Power Point Tracking) control function using the P&O algorithm and adopts constant voltage control method used in an existing inverter. This paper also implements a 2kW DC/DC voltage regulator based on the proposed algorithm and performs a variety of scenario-based experiments. From the simulation result, it was confirmed that the operation efficiency in the proposed method is improved compared to the existing method.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.95-103
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• 2021

This study was aimed to investigate the education needs for prevention and control of infectious diseases by lifecycle based on age group and to provide the fundamental data to develop the educational programs. A research was conducted with 328 adults over 19 years old for a month of February 2021 through online and mobile survey by Gallup Korea. Research contents include the general characteristics, personal hygiene practices related to infection, perceived risks related to infection, importance and level of knowledge on infectious diseases, and education needs for prevention and control of infectious diseases. For the research data analysis, PASW Statistics Ver 20.0 was used as a statistical program. Ranks from analysis upon conversion as the formula of Borich needs to sum up with importance and knowledge level showed first (Borich 3.11) with treatments for infectious diseases; second (Borich 2.15) with process in case of suspicion and diagnosis of infectious diseases; third (Borich 1.75) with transmission routes of infectious diseases; fourth (Borich 1.73) with preventive ways of infectious diseases; fifth (Borich 1.50) with diagnostic and test methods of infectious diseases; sixth (Borich 1.45) with characteristics of infectious diseases; and seventh (Borich1.38) with main symptoms of infectious diseases. It is anticipated that development of educational programs applying education needs for prevention and control of infectious diseases in this research can contribute to enhance the physical health, mental health, and psychological well-being of the subjects.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.9-22
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• 2022

The purpose of this study was to provide basic data on pre-service teacher's education based on cooperative learning-oriented teaching and learning methods by applying cooperative learning to verify the effectiveness of pre-service early childhood teacher's communication and problem-solving ability. In the first semester of 2021, 4th grade students who took the teaching method by subject class opened by department of early childhood education at C university were taught for 11 weeks from March 1st week to May 2nd week in 2021 for 4 hours a week. The results of this study were as follows: First, the average score of interpretive ability was the highest in the sub-areas of communication ability of pre-service early childhood teachers, followed by message conversion ability, role performance ability, self-presentation ability, and goal setting ability in the cooperative learning-oriented teaching method by subject class. Second, in terms of the overall average score of pre-service teacher's problem-solving ability, the average score of post-test was increased compared to the average score of pre-test. Through the cooperative learning-oriented class experience in the university's early childhood teacher training course, it is possible to cultivate the practical ability that can be used variously for the children such as communication ability and problem-solving ability in the early childhood education field. Therefore, it is necessary to provide opportunities for cooperative learning-oriented teaching methods in the teacher's education curriculum.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.101-109
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• 2010

Efficient L-lactic acid production from Jerusalem artichoke tubers, by Lactobacillus casei G-02, using simultaneous saccharification and fermentation (SSF) in a fed-batch culture, is demonstrated. A kinetic analysis of the SSF revealed that the inulinase activity was subjected to product inhibition, whereas the fermentation activity of G-02 was subjected to substrate inhibition. It was also found that the intracellular NADH oxidase (NOX) activity was enhanced by the citrate metabolism, which dramatically increased the carbon flux of the Embden-Meyerhof-Parnas (EMP) pathway, along with the production of ATP. As a result, when the SSF was carried out at $40^{\circ}C$ after an initial hydrolysis of 1 h and included a sodium citrate supplement of 10 g/l, an L-lactic acid concentration of 141.5 g/l was obtained after 30 h, with a volumetric productivity of 4.7 g/l/h. The conversion efficiency and product yield were 93.6% of the theoretical lactic acid yield and 52.4 g lactic acid/l00 g Jerusalem artichoke flour, respectively. Such a high concentration of lactic acid with a high productivity from Jerusalem artichokes has not been reported previously, making G-02 a potential candidate for the economic production of L-lactic acid from Jerusalem artichokes on a commercial scale.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.550-556
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• 2018

This study conducted AHP analysis to find out the directional of human resource management through policy priorities for personnel innovation of local public officials. The results of the study were derived using the AHP analysis methodology. The results of the study are summarized as follows. First, the interchange of personnel system was the most important measure among the measurement areas of interchange of personnel system, education training system, recruitment management system and appointment management system. Second, from the point of view of evaluation item, it is as follows. In the personnel interchange system, it was found that the conversion of personnel management based on job performance and performance was important. In the position management system, it is important to appoint and expand professional positions. In the recruitment management system, the introduction of personality and aptitude tests used in the private sector is important. Development of customized curriculum programs is important in the education and training system.

• The Journal of Korean Association of Computer Education
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• v.17 no.3
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• pp.101-112
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• 2014

With the development of information and communications technologies, there have been increasing cases of services and use free educational materials in educational field through the Web. However, as most of the materials are provided in a finished form via the Web services, teachers are in a situation where they have difficulty in using the materials through development or revision according to their educational goals. In this background, this study aimed to develop requirements and functions necessary for the educational contents development tools by having teachers as actual users develop contents using existing tools of the educational contents development. As a result, this study developed 10 requirements, including intuitive interface environment, support for various multimedia materials, and diversification of output versions etc. Also, the study suggested 13 functions, including links with external resources, automatic format conversion function, usage and editing of existing documents, writing learner's answers, and hiding function etc.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.261-267
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• 2010

We describe culture conditions for a high-efficiency in vitro regeneration system of Papaver nudicaule through somatic embryogenesis and secondary somatic embryogenesis. The embryogenic callus induction rate was highest when petiole explants were cultured on Murashige and Skoog (MS) medium containing 1.0 mg $1^{-1}$ ${\alpha}$-naphthaleneacetic acid (NAA) and 0.1 mg $1^{-1}$ 6-benzyladenine (BA) (36.7%). When transferred to plant growth regulator (PGR)-free medium, 430 somatic embryos formed asynchronously from 90 mg of embryogenic callus in each 100-ml flask. Early-stage somatic embryos were transferred to MS medium containing 1.0 mg $1^{-1}$ BA and 1.0 mg $1^{-1}$ NAA to germinate at high frequency (97.6%). One-third-strength MS medium with 1.0% sucrose and 1.0 mg $1^{-1}$ $GA_3$ had the highest frequency of plantlet conversion from somatic embryos (91.2%). Over 90% of regenerated plantlets were successfully acclimated in the greenhouse. Secondary somatic embryos were frequently induced directly when the excised hypocotyls of the primary somatic embryos were cultured on MS medium without PGRs. Sucrose concentration significantly affected the induction of secondary embryos. The highest induction rate (89.5) and number of secondary somatic embryos per explant (9.3) were obtained by 1% sucrose. Most secondary embryos (87.2-94.3%) developed into the cotyledonary stage on induction medium. All cotyledonary secondary embryos were converted into plantlets both in liquid and on semisolid 1/3-strength MS medium with 1.0% sucrose.

• Analytical Science and Technology
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• v.17 no.3
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• pp.225-229
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• 2004

The effect of the silicon acrylate as a reactive additive on the UV-curing photopolymerization reaction was studied by micro raman technique. For the study, acrylate systems and Darocur 1173 were used as oligomer and monomers, and a photo initiator, respectively. The content of silicon acrylate was within the range of 0-3 wt%. The extent of photo-polymerization reaction as a function of depth from the air interface was obtained from the conversion ratio of acrylate double bond calculated from the intensities of measured bands at $1410cm^{-1}$ and at $1635cm^{-1}$. Micro raman spectroscopic technique can be an useful tool for the investigation of the factors, which can affect the reaction progress, such as oxygen inhibition, composition of the formulations, depth, etc.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.4
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• pp.522-538
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• 2015

The objective of this study was to review how contract farming started in Gochang-gun and identified its characteristics among the contracting parties and the consequent changes in the region's dairy industry with regard to the contract production of organic milk in Gochang-gun, Jeollabuk-do, Korea in conjunction with the Maeil Dairy Industry Corporation. The contract was established in keeping with the product diversification strategy of the company after a crisis due to opening of the market, taking advantage of the clean environment of Gochang-gun and positive attitudes of the local government and dairy farmers. The expansion of the participating farms led to a production gap among dairy farms in the region; however, the overall concern over the conventional practice of contract farming was mitigated as the organic farming spread with the conversion of the contract farms to organic farms.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.191-197
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• 2012

In this paper we present creating 3D image from 2D image by extract initial depth values calculated from focal values. The initial depth values are created by using the extracted focal information, which is calculated by the comparison of original image and Gaussian filtered image. This initial depth information is allocated to the object segments obtained from normalized cut technique. Then the depth of the objects are corrected to the average of depth values in the objects so that the single object can have the same depth. The generated depth is used to convert to 3D image using DIBR(Depth Image Based Rendering) and the generated 3D image is compared to the images generated by other techniques.