• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.3
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• pp.85-98
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• 2021

In this study, the characteristics of tree growth and soil environment were analyzed at 5 sites that had been planted on the back slope of dam for more than 15 years in Korea. First, as a result of investigating the growth of 15 trees planted on the back slope of the dam, the average height was 10.6m, diameter at roots was 27.3cm, and DBH was 22.9cm, showing good growth status of most of the trees. In particular, the growth levels of pine, hackberry, and oak were similar or better than those of general forests and artificial ground. As a result of excavating and investigating the roots of trees, horizontal roots grew well in the left and right directions of the back slope of the dam, and the growth of vertical roots was insufficient. Currently, the roots of trees do not directly affect dam safety, but they may continue to grow in the long term and interfere with dam management. Second, the physicochemical characteristics of the soil on the back slope of dam were generally above the intermediate level in terms of landscape design standards, and were similar to those of the domestic forest soil. Therefore, although it was judged to be suitable for plant growth, isolation of the site, soil acidification, and nutrient imbalance may affect tree growth and forest health in the long term. Through this study, it was possible to confirm the potential and applicability of planting area on the back slope of dam as an ecological base. Continuous monitoring is required for safety management and ecological value of dams in the future, and through this, it will be possible to secure the feasibility of planting trees on the slopes of new or existing dams and improving management.

• Computers and Concrete
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• v.27 no.5
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• pp.457-472
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• 2021

Reinforced concrete (RC) buildings in Taiwan have suffered failure from strong earthquakes, which was magnified by the non-ductile detailing frames. Inadequate reinforcement as a consequence of the design philosophy prior to the introduction of current standards resulted in severe damage in the column and beam-column joint (BCJ). This study establishes a finite element analysis (FEA) of the non-ductile detailing RC column, BCJ, and three-story building that was previously tested through a tri-axial shaking table test. The results were then validated to laboratory specimens having the exact same dimensions and properties. FEA simulation integrates the concrete damage plasticity model and the elastic-perfectly plastic model for steel. The load-displacement responses of the column and BCJ specimens obtained from FEA were in a reasonable agreement with the experimental curves. The resulting initial stiffness and maximum base shear were found to be a close approximation to the experimental results. Also, the findings of a dynamic analysis of the three-story building showed that the time-history data of acceleration and displacement correlated well with the shaking table test results. This indicates the FEA implementation can be effectively used to predict the RC frame performance and failure mode under seismic loads.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.4
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• pp.508-514
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• 2020

To implement the continuously evolving mobile communication standards such as Long Term Evolution (LTE) and 5G, the Software Defined Radio (SDR) concept provides great flexibility and efficiency. For many years, a high-end Digital Signal Processor (DSP) System on Chip (SoC) has been developed to support multicore and various hardware coprocessors. This paper introduces the implementation of the SDR platform hardware using TI's TCI663x chip. Using the platform, LTE transport channel is implemented by interworking multicore DSP with Bit rate Coprocessor (BCP) and Turbo Decoder Coprocessor (TCP) and the performance is evaluated according to various implementation options. In order to evaluate the performance of the implemented LTE transport channel, LTE base station system was constructed by combining FPGA main board for physical channels, SDR platform board, and RF & Antenna board.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.652-662
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• 2022

Currently, in the field of spinal surgery around the world, various new technologies have been rapidly developed and applied to patients. The author believes that it is necessary to discuss whether these new technologies are being fully reviewed for efficacy and safety before being applied to patients. To consider this issue, the author analyzed the basic research data and clinical application process of the intradiscal electrothermal therapy, which was developed as a new technology for discogenic pain disease in the 2000s and has been widely used worldwide. As a result, it was found that this procedure has been performed on patients in a state where there is insufficient base research on efficacy and safety. The author judges that this case reveals an essential problem related to the clinical operation of new medical technologies in the field of spine surgery. Therefore, the author believes that in order to minimize the side effects that new medical technology in the field of spinal surgery may have on patients, more full-fledged basic research and higher clinical acceptance standards should be established.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.815-824
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• 2022

The growing integration of intermittent renewable sources like offshore wind energy increases the need for transferring electric energy over long distances, which may include sea crossings. One of the solutions available for bulk electric power transmission across large distances encompassing wide and deep sea is using HVDC submarine power cables. However, there are no standards or research related to the calculation of the continuous allowable current with various ocean conditions of a DC power cable that does not have an alternating magnetic field. In this study, assuming the typical two types of subsea cable models and two areas of the south coast and the west coast marine conditions, a continuous allowable current simulation of DC cables was performed. As a simulation result, the DC cable continuous allowable current find out the gradient reduction characteristics based on subsea base depth.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.22-32
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• 2023

In general, when scrap is dissolved in an electric arc furnace, the amount of electric furnace steel dust (EAFD) generated is about 1.5% of the scrap charge amount, and the electric furnace steel dust collected by the bag filter is charged into the Rotary Kiln or Rotary Hearth Furnace (RHF), and the zinc component is recovered as crude zinc oxide, at which time a clinker of Fe-Base is generated. In this research, first, for the efficient resource conversion of electric furnace steel dust, a reduction and roasting experiment was conducted and the reaction kinetics was examined. As a result of the experiment, it was observed that the reduction and roasting reaction was actively conducted in the range of 1100~1150℃, and melting occurred in the range of 1250℃. In the past, this clinker was widely used as a roadbed material for road construction and an Fe-Source for cement production, but in recent years, it has been mainly reclaimed due to strengthening environmental standards. However, landfill treatment is by no means a desirable treatment method due to environmental pollution caused by leachate, expensive landfill costs, and waste of Fe resources. Therefore, in order to more actively recycle the Fe component in the clinker, first of all the clinker was pulverized into an optimal particle size, and anthracite and binder (starch) were added to the magnetic material obtained by specific gravity and magnetic separation for briquet. As a experimental results, it was possible to efficiently separate clinker as Fe component and other slag component by specific gravity and magnetic force. As a results of loading and dissolving the manufactured briquet clinker in an electric arc furnace, it was observed that the unit of power and production yield were clearly improved and the carbon addition effect in molten metal was also somewhat.

• Journal of Environmental Science International
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• v.32 no.12
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• pp.915-923
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• 2023

The purpose of the study is to explore strategies to revitalize the distribution of landscaping plants in Gangwon State (hereinafter referred to as Gangwon-do). To understand the current distribution status and perception of landscape materials in Gangwon-do, a survey was conducted on producers and consumers focusing on cultivation area and method, cultivated species and quantity, purchase species and quantity, and purchase area. Producers often cultivated open land, and in the case of trees and shrubs, most of them cultivated <5 species. On the other hand, consumers preferred field cultivation products when purchasing trees and shrubs. Approximately 6-10 species of trees and shrubs were preferred for a single purchase, confirming an imbalance in the supply and demand of landscaping plants. In addition, both producers and consumers had a positive perception of landscape plant transactions in Gangwon-do; however, the dissatisfaction factors for producers included a small consumer base and difficulties for them in securing standards and quantities. Based on these results, it is necessary to establish a platform that can interconnect producers' landscape plant cultivation information with consumers' requirements to rejuvenate the landscape plant distribution market and enhance competitiveness in Gangwon-do. In addition, this platform is expected to have a positive impact on improving the quality of landscaping plants, setting reasonable prices, and increasing domestic demand in Gangwon-do by providing opportunities for cultivation, promotion, and marketing education through producer support projects.

• Journal of The Korean Association For Science Education
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• v.28 no.6
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• pp.618-632
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• 2008

Despite the rapidly growing body of research on science teachers' pedagogical content knowledge (PCK), most of the research has mainly focused on the definition of PCK and its components. The main purpose of this research was to explore the operational definition of PCK and to suggest another form by re-conceptualizing PCK, with the newly defined and conceptualized PCK capable of being used as standards and/or criteria in selecting the curricular content of and deciding the subject area of science teacher education. In this research, the science teachers' PCK was defined as the "practical knowledge and skills that are acquired through the curriculum of science education and in the course of teaching experiences, and which are used in their teaching of secondary school science." The science teachers' PCK was further defined as consisting of two integrated and/or combined dimensions: subject matter and pedagogy, each of which comprises several components. In this paper, the PCK is called science education literacy. The paper also presents the ways to apply the operational definition of PCK and re-conceptualized PCK and a few suggestions for the research on science teachers' PCK.

• Korean Journal of Radiology
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• v.25 no.7
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• pp.603-612
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• 2024

Artificial intelligence (AI) is rapidly gaining recognition in the radiology domain as a greater number of radiologists are becoming AI-literate. However, the adoption and implementation of AI solutions in clinical settings have been slow, with points of contention. A group of AI users comprising mainly clinical radiologists across various Asian countries, including India, Japan, Malaysia, Singapore, Taiwan, Thailand, and Uzbekistan, formed the working group. This study aimed to draft position statements regarding the application and clinical deployment of AI in radiology. The primary aim is to raise awareness among the general public, promote professional interest and discussion, clarify ethical considerations when implementing AI technology, and engage the radiology profession in the ever-changing clinical practice. These position statements highlight pertinent issues that need to be addressed between care providers and care recipients. More importantly, this will help legalize the use of non-human instruments in clinical deployment without compromising ethical considerations, decision-making precision, and clinical professional standards. We base our study on four main principles of medical care-respect for patient autonomy, beneficence, non-maleficence, and justice.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.465-472
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• 2008

Diverse methods of life guidance adopted by the teacher's subjective standards including corporal punishment have inherent problems. Some schools have introduced and exercised the merit and demerit system, which uses merits and demerits to guide the children for desirable life habits and etiquette. And most of them are done off-line and thus have difficulties with real time reference, statistical process, filling out logs, and management. The merit and demerit management system(MDMS) was developed to support the process, statistics, reference, and authority features as well as card issuing. It also promotes life guidance, personality education, participation of the parents, and further desirable cooperation among the teachers, students, and parents. The system has lots of advantages such as reducing resistance from the students against life guidance rules, enabling the students to check their life guidance status at school, allowing the parents to check how their children are doing at school, increasing efficiency of data management, and taking some burden off the shoulders of the teachers doing statistics. MDMS helps the teachers base corporal punishment on the guidance rules, deter direct punishment on certain body parts, and pursue more systematic, scientific, and human life guidance.