• Communications of Mathematical Education
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• v.37 no.3
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• pp.517-544
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• 2023

This study presents the process and outcomes of developing mathematical-informatics linkage·convergence class materials, based on previous research findings that indicate a lack of such materials in high schools despite the increasing need for development of interdisciplinary linkage·convergence class materials In particular, this research provides insights into the discussions of six teachers who participated in the same professional learning community program, aiming to create materials that are suitable for linkage·convergence class materials and highly practical for classroom implementation. Following the material development process, a theme-based design model was applied to create the materials. In alignment with prior research and consensus among teacher learning community members, mathematics and informatics teachers developed instructional materials that can be utilized together during a 100-minute block lesson. The developed materials utilize societal issue contexts to establish links between the two subjects, enabling students to engage in problem-solving through mathematical modeling and coding. To increase the validity and practicality of the developed resources during their field application, CVR verification was conducted involving field teachers. Incorporating the results of the CVR verification, the finalized instructional materials were presented in the form of a teaching guide. Furthermore, we aimed to provide insights into the trial-and-error experiences and deliberations of the developers throughout the material development process, with the intention of offering valuable information that can serve as a foundation for conducting related research by field researchers. These research findings hold value as empirical evidence that can explore the applicability of teaching material development models in fields. The accumulation of such materials is expected to facilitate a cyclical relationship between theoretical teaching models and practical classroom applications.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.93-104
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• 2024

Facility diagnosis is essential for the smooth operation and life extension of rotating equipment used in industrial sites. Compared to other diagnostic methods, vibration diagnosis can find most of the initial defects, such as unbalance, alignment failure, bearing defects and resonance, compared to other diagnostic methods. Therefore, vibration analysis is the most commonly used facility diagnosis method in industrial sites, and is usefully used as a predictive preservation (PdM) technology to manage the condition of the facility. However, since the vibration diagnosis method is performed based on experience based on the standard, it is carried out by experts. Therefore, it is intended to contribute to the reliability of the facility by establishing a system that anyone can easily judge defects by establishing a vibration diagnosis method performed based on experience as a knowledgeable code system. An algorithm was developed based on the ISO-20816 standard for vibration measurement, and the reliability was verified by comparing the results of vibration measurement at various demonstration sites such as petrochemical plant compressors, hydrogen charging stations, and industrial machinery with the results of analysis using a development system. The developed algorithm can contribute to predictive maintenance (PdM) technology that anyone can diagnose the condition of the rotating machine at industrial sites and identify defects early to replace parts at the exact time of replacement. Furthermore, it is expected that it will contribute to reducing maintenance costs and downtime due to the failure of rotating machines when applied to various industrial sites such as oil refining facilities, transportation, production facilities, and aviation facilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.555-565
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• 2018

Nowadays, the artificial ground freezing (AGF) method has been used in many geotechnical engineering applications such as temporary excavation support, underpinning, and groundwater cutoff. The AGF method conducts the freezing process by employing a refrigerant circulating through a set of embedded freezing pipes to form frozen walls serving as an excavation support and cutoff wall. Two refrigerants of brine with the freezing temperature of $-20{\sim}-40^{\circ}C$ and liquid nitrogen with the freezing (evaporating) temperature of $-196^{\circ}C$ are commonly being used in geotechnical applications. This paper performed a series of field experiments to evaluate the freezing rate of marine clay in application of the AGF method. The field experiments consisted of the single freezing-pipe test and the frozen-wall formation test by circulating liquid nitrogen, which is a cryogenic refrigerant, into freezing pipes constructed at a depth of 3.2 m in the ground. The temperature of discharged liquid nitrogen was maintained through the automatic valve, and the temperature change induced by AGF method was measured at the freezing pipes and in the ground with time. According to the experimental results, the single freezing-pipe test consumed about 11.9 tons of liquid nitrogen for 3.5 days to form a cylindrical frozen body with the volume of about $2.12m^3$. In addition, the frozen-wall formation test used about 18 tons of liquid nitrogen for 4.1 days to form a frozen wall with the volume of about $7.04m^3$. The radial freezing rate decreased with increasing the radius of frozen body because the frozen area at a certain depth is proportional to the square of the radius. The radial freezing rate was formulated as a simple equation.

• Journal of Sasang Constitutional Medicine
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• v.12 no.1
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• pp.37-47
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• 2000

We detect lots of problems on the manufacturing spot because of working results done without considering the aptitude and inherited temper(constitution, blood type, male and female) of the worker, and they lead to results not only the occupational disease and the cause of industrial accidents but also quality deterioration and productivity reduction in point of view of manufacturing management. For the purpose of solving these problems, this study is perfomed by grasping the correlation sasang constitutions and job characteristic of small & medium enterprises. We classify sasang constitutions to four types : so-yang-in type, tae-yang-in type, tae-em-in type, so-em-in type by the utilization of QSCC II and the doctor aid of oriental medicine, and also survey differences of classified sasang constitutions with previous studies. This study tries to identify significant features between major jobs resulting from sasang constitution types in a specific small & medium enterprise producing agricultural machinery(a tractor, a combine, etc). The results of this case study indicate that sasang constitution types influences job types. Under the working conditions that virtual reality scene photographed by video camera are running, also the effects of brain function of each worker using Electroencephalograms(EEGs) are investigated. Electroencephalograms(EEGs) provide much information about the brain function, such as relaxation, concentration, various thoughts and so on. Previous studies reported the appearance of ${\theta}$ waves and an increase in the ${\alpha}$ waves during psychologically satisfaction conditions. An statistical analysis of experiments conducted shows the various changes of brain waves(${\alpha},{\beta},{\theta},{\delta}$ waves). By means of these study results, we can identify that sasang constitutions should be applied to contribute much to quality advancement and productivity improvement through a comparative study on the job characteristic.

• Journal of Agricultural Extension & Community Development
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• v.21 no.4
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• pp.1149-1189
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• 2014

Nowadays, many farmers use online management diagnosis tool developed by Rural development agency(RDA) for the purpose of self-diagnosis of their farm management. Database(DB) was created using the diagnosis results and has been used for agri-firm management consulting. However, the amount of diagnosis data in the DB has been decreasing year by year. This means that the diagnosis tool of RDA did not reach farmers' expectation. Therefore it is necessary to develop a practical consulting tool which is applicable for various types of agri-firm management. This study introduces a management diagnosis tool and consulting method based on multi-contingency organization theory and value chain model for the purpose of improving existing tools and methods. The consulting method based on multi-contingency organization theory shows the core strategy of agri-firms by two different ways such as "efficiency-oriented" direction and "effectiveness-orientated" direction. Also, this method emphasizes that the performance of firm can be achieved when subelements of firm activities follow the same direction with the orientation of core strategy. The important thing is the right firm management activity fitted to its strategic direction. Through this action, limited firm resources can be optimized. In order to make itself understand, this study shows a practical example applied by this method from actual agri-firms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.235-246
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• 2009

The number of industry wireless networks based on IEEE 802.11 WLAN technology deployed in large outdoor work sites, such as freight container terminal, is increasing these days. Wider service coverage, frequent movements of stations and high requirement on service reliability are main characteristics of these networks compared to the conventional IEEE 802.11 networks used in home, office and school. While the importance of these networks Bets higher, we can hardly find previous studies including concrete analysis on these networks based on actual experiments. We carried out several field experiments at a freight container terminal to analyze its IEEE 802.11 network and found out some problematic situations, such as over 50% retransmission rates and frequent disruption of communication link while a station is moving. We explain why these problematic situations happen and suggest some solutions, such as application of mesh technology, smart handoff based on location and movement pattern and adjustment of signal strength and channel allocation. Methods and tools used in the experiments are also detailed in the paper which may be helpful for similar future studies.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.352-361
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• 2016

This research examines how influential the certificate is on career development and job satisfaction. The outcome of substantial analysis on hypothesis of the study is: First, three factors-proactiveness, value, competitiveness are the positive effect on motivation for certificate. However, it is shown that the correlation and regulation factors do not have a significant effect on career development. Second, career development has a positive relation with the job satisfaction. Third, value and association among motivation factors for certificate acquisition have a positive effect on job satisfaction. However, it is revealed that proactiveness, competitiveness, and bylaw factors do not have significant influences on job satisfaction. These outcomes prove that private certificates do not meet the need realistically in the business field. It is caused by the low level of difficulty of the certificate exam, which results in the standardization state where it becomes easier for anyone to obtain the certificate. In order to resolve the problem in relation to the private certificate acquisition, it is suggested that advices of field experts should be actively reflected on the exam and that the difficulty of the exam should be moderated to acquire comparability and to reflect reality.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.166-170
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• 2006

본 연구에서는 폐광산 주변에 산재되어 있는 광미/광폐석을 처리하기 위하여 고형화 실증 실험을 수행하였다. 고형화 공정에서 흔히 사용하는 포틀랜드 시멘트와 MSG-E, MSG-N을 고화제로 사용하였으며 현장 광미 및 광폐석을 대상으로 고화체를 양생하고 고화체의 압축강도 및 중금속 용출 정도를 측정하였다. 고화체의 물리/화학적 특성을 비교하기 위해 광미/고화제 비율, 배합수/고화제 비율 그리고 고화체 양생기간을 실험인자로 설정하였다. 실험 결과 광미/고화제의 비율 1:1 만을 고려하더라도 중금속 용출의 급격한 감소가 이루어지는 것을 확인할 수 있었으며 광미/고화제의 비율을 3:1 이하로 유지시키는 경우, 고화체의 압축강도가 현행 폐기물 관리법(20조 관련)에서 규정하고 있는 차단형 매립시설 내부막의 압축강도 기준인 $0.21kgf/mm^2$ 보다 높은 것으로 나타났다. 다양한 pH를 갖는 수용액에 대하여 시간에 따른 고화체의 중금속 용출률을 측정한 결과, 수용액의 pH가 1과 13인 강산/강염기 용액에서 일부 중금속의 용출 농도가 지하수 생활용수 기준치를 초과하였으나, pH와 3 - 11인 경우에는 중금속 용출률이 급격히 감소하여 모두 기준치 이하를 나타내었다. 또한, pH가 1과 13인 수용액의 경우에도 고화체와 반응하는 시간이 증가할수록 고화체의 buffering 효과에 의해 수용액의 pH가 감소하였다. 이러한 결과는 현장에서 접촉수의 pH가 강산이나 강염기라 하여도, 고화체의 buffering 효과에 의해 시간이 지남에 따라 수용액의 pH가 낮아져 고화체로부터의 중금속 용출은 매우 감소할 것임을 의미한다.ss of an active application defined using the model. The technique is developed in a platform- and language-independent way, and it is algorithmic and can be automated by computer program. We give an example dealing with network auction to illustrate the use of the model and the verification technique.품으로 내부 온도분포를 측정하였으며, 유한차분법 프로그램으로 대류열전달계수를 결정하였다. 대류열전달계수는 792에서 2,107 W/m$^2$로 분석되었다. 대류열전달 계수는 액상식품과의 상대속도가 증가함에 따라서 증가하였고, 점도가 증가함에 따라서는 감소하였다.ce of precision/recall of 90.99%/92.52%, and 93.39%/93.41% respectively. 의한 변성에 부분적으로 보호 작용을 나타 낼 것으로 추정된다.경(製麴72時間頃)의 활성(活性)은 보리쌀국(麴), 밀가루국(麴), 찹쌀국(麴), 고구마국(麴)의 순이었다.험 결과 오전용 사료는 관행적인 산란계 배합사료에서 Ca공급제를 제외한 것을 급여하고, 오후용 사료는 Ca공급제를 3배 첨가한 T2처리로 15:00~16:00시에 교체급여를 하면 사료섭취량 감소와 사료비 절감면에서 바람직할 것으로 사료되며, 고에너지-고단백질-저Ca의 분말사료와 저에너지-저단백질-고Ca의 펠렛사료를 혼합급여하면 산란계의 사료

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.445-460
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• 2017

This study was carried out for three years from 2013 to 2015 to investigate the actual condition of pest control of domestic persimmon organically cultivated farmers, to select environment - friendly pest control materials for major pests, and to conduct field test of established control system. The main cultivated cultivar of the reader farmer of organic cultivation was "Buyou" and sprayed organic agricultural material 9~17 times per year for pest control. The most harmful pests were anthracnose, bugs, persimmon fruit worm, and scales, etc. The control materials used were organic lime sulfur mixture, red clay sulfur, emulsifier, bordeaux solution, and self-made plant extracts using garlic, ginkgo nut and pine tree. The effective materials for controlling anthrax were lime sulfur mixture and red clay sulfur. Garlic oil + citronella emulsion, shrubby sophora seed extract + tea extract was effective to control Riptortus clavatus and Euproctis subflava. When installed 60 ea per 10a of mating disruption trap in a sweet orchard, the fruit setting rate was improved by 30%. The results of field test of control system to control 10 times a year in organically grown persimmons were able to harvest fruit of 70.7%. However, since any kinds of pesticides can not be sprayed during the harvest season in September and October, the damaged by bugs did not decreased, and further research is needed.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.49-57
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• 2021

As the world marks the adoption of the landmark Paris Agreement on climate change, a promising movement for carbon neutrality is taking shape. This agreement would be needed to build a truly global coalition for carbon neutrality by 2050. Greenhouse gas(GHGs) emissions from agriculture come from livestock such as cows, agricultural soils and rice production has been reported by 10% in 2019. Rice cultivation would be reduced a GHGs and thus this research has conducted to minimize the emission of greenhouse gas with the mulching methodology using a biodegradable film in dry hill seeded rice and to conserve the environment through a cultural and ecological weed control instead of chemicals. We have developed the 5^th mulching dry hill seeder with the biodegradable film to determine the possibility of stable rice cultivation. There were so many difficulties and constraints in the field operations such as film mulching, hill seeding and effective weed control. The mulching dry hill seeder was so good performance in the 5^th trial but the biodegradable film tested was so faster in terms of biodegradation before the heading stage of the rice plant and thus there was not highly effective weed control which is ongoing research with a good performance since 2020.