• Smart Media Journal
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• v.9 no.4
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• pp.176-186
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• 2020

The size and shape of crops are diverse, and the growing environment is also different. Therefore, when one uses a drone to spray pesticides, the characteristics of each crop must be considered, and flight conditions such as the flight height and forwarding velocity of the drone should be changed. The droplet flow of pesticides is affected by various flight conditions, and a large change occurs in the sprayed area. As a result, an uneven distribution of liquid may be formed at the wake, and the transport efficiency will be decreased as well as there would be a risk of toxic scatter. Therefore, this paper analyzes the degree of distribution of pesticides to the crops through numerical analysis when pesticide is sprayed onto the selected three crops with different characteristics by using agricultural drones with different flight conditions. On the purpose of establishing a guideline for spraying pesticides using a drone in accordance with the characteristics of crops, this paper compares the amount of pesticides distributed in the crops at the wake of nozzle flow using the figure of merit, and the sum of transported liquid rate divided by the root mean square of the probability density function.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.4
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• pp.1-14
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• 2021

This study examined the techniques of creating gardens overseas using native plants from the Korean peninsula, focusing on the case of 'Das Dritte Land', an art garden created in Berlin, Germany. While Korean garden artists are recognized worldwide and are planning to globalize Korean gardens, the purpose of this study is to share information so that Korean gardeners can expand their activities and rediscover the utilization and value of plants native to the Korean peninsula. The work began as part of a project to mark the 30th anniversary of the collapse of the Berlin Wall. To realize the landscape of Korea with the motif of Inwang Jesaekdo, the geographical shape of the Baekdu-Daegan trail was reproduced with black stone, and the naturalization of Korean peninsula species was utilized in the creation of a garden Berlin. It is a surreal bio-top utopia that blooms with the bio-groups of the Korean peninsula. This study examined the process of plant survey analysis, transportation and stabilization, planting planning, composition and monitoring, and targeting the self-growth of the Korean peninsula, which is a symbol of harmony between the South and the North. The planting of Korea's native plants in overseas gardens symbolizes the uniting of the ecosystems on the Korean peninsula. The process of the Korean peninsula's young plants taking root, flowering, and spreading along Germany's previously divided border metaphorically conveys the desire for the unification of the Korean peninsula. In addition, various art programs in the garden space suggest a foundation for cultural dialogue and communication between the two Koreas. Moreover, creating gardens overseas implies that the cooperation of plant research institutes plays an important role in the transfer of plants and the maintenance of life, while the advancement of Korean gardens overseas plays an essential role in the spread of garden culture in our country.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.53-65
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• 2021

While the hydrogen refueling station is rapidly expanded and installed, the safety inspection of the hydrogen pressure vessel in the station should be very important. Of these, according to ASME, hydrogen embrittlement tests must be performed for hydrogen vessel that store hydrogen above a certain pressure. The main test method for hydrogen embrittlement inspection is to carry out fracture tests and fatigue fracture tests in a high pressure hydrogen atmosphere, which allows the durability limit of the pressure vessel to be measured and the endurable limit to be determined in the hydrogen atmosphere. In detail, the critical crack depth can be calculated by the stress intensity factor(K), and the service life can be determined by da/dN (fatigue growth rate). API579-1/ ASME FFS-1 part 9 exemplifies the calculation method according to the mode of crack-like flaws, but for various shapes such as plates and cylinders, there are about 55 modes according to the shape and location of the crack. Due to the fairly complex formula, it is not easily accessible. In this study, we will show you how to calculate fracture mechanics numerically via Excel and VBA. In addition, this was applied to analyze the effects of the thickness and inner diameter of the pressure vessel on the service life.

• Land and Housing Review
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• v.13 no.1
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• pp.55-65
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• 2022

This paper investigates the distinct characteristics of freehold and leasehold households living in the seven largest cities and the other areas. We employ the two-stage logit regression analysis to identify the marginal effects of wealth and income after controlling for the other one. We document the following results. First, households with more net wealth are more likely to reside in their own houses, regardless of living areas. Second, the pure income effect after controlling for wealth and other variables lowers the tendency of freeholders to live in the seven largest cities while increasing the tendency to live in the other areas. Furthermore, the income effects reduce the tendency to live in the former regions. Our results suggest that the pure income effects enhance preferences for a better living environment (e.g., larger spaces, better school districts, etc.), whereas the wealth effect increases the likelihood of freeholds.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.217-222
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• 2022

It is very important to analyze the OCV change behavior during the open circuit potential holding (OCV holding) process, which accelerates the evaluation of the electrochemical durability of the PEMFC membrane. In this study, an empirical formula using the experimental data of three MEAs with different durability was created and compared. The durability evaluation time of the reinforced membrane MEA without radical scavenger inside the membrane was 383 h, and the durability evaluation time of the reinforced membrane MEA with radical scavenger inside the membrane was 1,000 and 1,650 h, respectively. The degradation of the membrane was divided into the reversible degradation that can be recovered by activation and the irreversible degradation that is not recovered. The irreversible degradation of the membrane was indicated by an increase in hydrogen permeability, and the change in hydrogen permeability was similar to the irreversible degradation constant c of all three MEAs. The initiation of irreversible deterioration without recovery is indicated by an increase in hydrogen permeability, and the OCV is not recovered due to an increase in hydrogen permeability, so the slope of the OCV recovery line (ORL) decreases, which can be confirmed by an increase in the constant c value of the empirical formula.

• Journal of The Korean Association For Science Education
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• v.42 no.2
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• pp.201-214
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• 2022

The purpose of this study is to examine the characteristics of model of the experiment in students' open inquiry. The research is a reinterpretation of the data collected from the performance of a three-year research project under the theme of 'school science inquiry' the perspective of model of the experiment. The inquiry activities of a focus group made up of four students have been recorded seven times. The recorded files and transcribed copies were analyzed according to interpretive methods. Students' activities were divided into three modeling of the experiment units, considering the modeling unit that includes the process of starting from the problem until it gets solved. The results of the study include illuminating the dynamic process and characteristics of modeling of the experiment and discussing its educational meaning as a distributed cognitive system at each modeling unit. First, students, instruments, and the primitive form of calculation represented by the interaction between them turned out to be important factors in the distributed cognitive system that constitutes model of the experiment. Second, in the early stages, non-verbal activities were carried out in which students became familiar with instruments, and verbal quantitative signs were created when the activities were sufficiently carried out. The generated quantitative signs became a source of data and confidence that can be referenced in subsequent activities. Third, the specialization of instrumentalization occurred, and factors that were important in inquiry, such as variable control, appeared. The results of the study provide new implications for science education research and education, which have been centered on explanatory models, by unfolding the characteristics of model of the experiment that have not been noticed in science education through students' inquiry.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.11-16
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• 2022

Metal-organic frameworks (MOFs) are porous materials with nano-sized pores. The degree of gas adsorption and pore size can be controlled according to types of metal ions and organic ligands. Many studies have been conducted on MOFs in the fields of gas storage and separation, and gas sensors. For rapid and quantitative gas adsorption/desorption analyses, it is necessary to form various MOF structures in uniform films on a sensor surface. In this review, some of representative direct methods for uniformly synthesizing MOFs such as MIL-53 (Al), ZIF-8, and Cu-BDC from anodized aluminum oxide, zinc oxide nanorods, and copper thin films, respectively on the surface of a microresonator are highlighted. In addition, the operation principle of quartz crystal microbalance and microcantilever, which are representative microresonators, and the interpretation of signals that change when gas is adsorbed to MOFs are covered. This is intended to enhance the understanding of gas adsorption/desorption analysis of MOFs using microresonators.

• Journal of Practical Engineering Education
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• v.13 no.3
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• pp.461-471
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• 2021

This study investigated the application and satisfaction of the global industrial technology curriculum for foreign students at J University in Korea. In order to derive the global industrial technology curriculum, industry needs were analyzed, and the appropriateness of the curriculum was identified through the current status of the root industry. In order to investigate the satisfaction with the application of the global industrial technology curriculum, a questionnaire survey was conducted in the form of an in-person interview for two months from August to September 2021 for foreign students. The questionnaire surveys included general information of the subjects, the status of completion of the curriculum, questions about class satisfaction, the process of obtaining certifications, and whether or not they were employed. As a result of the study, the reasons for choosing the curriculum of the respondents were their interest in subjects related to the root industry (welding, machining, etc.) and the issuance of Korean employment and visas (E-7). The most preferred subject was welding practice at 36.8%, and in terms of subjects considered necessary, the subject of basic major terminology was the most at 29.2%. The difference in satisfaction between graduates and current students who applied the same curriculum was tested, and as a result of the analysis, it was confirmed that there was no difference in satisfaction between current students and graduates through the t test (significance level p=0.05). We believe that this study is meaningful in that it provides basic data for the domestic industrial technology curriculum for foreign students and suggests the direction of related research in a time when the existence of universities is threatened due to the decrease in the school-age population.

• Knowledge Management Research
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• v.23 no.3
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• pp.129-152
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• 2022

As a key infrastructure for digital transformation, the spread of data, network, artificial intelligence (D.N.A.) fields and the emergence of promising industries are laying the groundwork for active digital innovation throughout the economy. In this study, by applying the text mining methodology, major topics were derived by using the abstract, publication year, and research field of the study corresponding to the SCIE, SSCI, and A&HCI indexes of the WoS database as input variables. First, main keywords were identified through TF and TF-IDF analysis based on word appearance frequency, and then topic modeling was performed using g-DMR. With the advantage of the topic model that can utilize various types of variables as meta information, it was possible to properly explore the meaning beyond simply deriving a topic. According to the analysis results, topics such as business intelligence, manufacturing production systems, service value creation, telemedicine, and digital education were identified as major research topics in digital transformation. To summarize the results of topic modeling, 1) research on business intelligence has been actively conducted in all areas after COVID-19, and 2) issues such as intelligent manufacturing solutions and metaverses have emerged in the manufacturing field. It has been confirmed that the topic of production systems is receiving attention once again. Finally, 3) Although the topic itself can be viewed separately in terms of technology and service, it was found that it is undesirable to interpret it separately because a number of studies comprehensively deal with various services applied by combining the relevant technologies.

• Journal of Christian Education in Korea
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• v.71
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• pp.23-59
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• 2022

This paper explored the effect of digital epistemology on Christian education. The media of an era determines the type and form of the epistemology of that era, which in turn has a decisive influence on the direction of Christian education in that era. Therefore, it consists of three parts. First, an investigation on the relationship between media and epistemology, second, an investigation on digital epistemology, and third, an investigation on the effect of digital epistemology on Christian education. In this paper, first, from the perspective of McLuhan's media theory, it was discovered that media go beyond simply expanding the our senses and change our perception through creating a new environment and way of life. This paper could characterize digital epistemology in the following four ways through comparison with the traditional epistemology of the print media era: namely "from linguistic to omnisensory epistemology", "from causality to relational epistemology", "from historical to post-historical thinking", and "from interpretive to performative epistemology". In addition, it examined the effects of that digital epistemology on Christian education. Through this study, it found that digital media can act both positively and negatively on the essence of Christian education. Therefore, the task of Christian education in the digital age is to make it a positive function rather than a dysfunctional one, and an opportunity rather than a challenge.