• Journal of Korean Elementary Science Education
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• v.37 no.1
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• pp.27-38
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• 2018

The purpose of this study was to investigate the perceptions of the students about professionalism on the elementary teachers' science teaching through network analysis of keyword. For this study, questionnaires were conducted to elementary school students. The collected data were translated by coding and data cleaning. And then analyzed by Gephi 0.9.2 program as a tool of the network analysis. The results of this study were as follows: Top 5 words in betweenness centrality were 'smart, experiment, fun, various, and student understanding'. There was some difference of perceptions of students according to personal backgrounds(gender, grade and interest toward science class). Based on the result of this study, implications to improve elementary teachers' science teaching professionalism were suggested.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.209.2-209.2
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• 2014

In recent years, researches about hydrophobic and hydrophilic surfaces have been executed however their other effects have not been researched enough. In this paper, the fabrication method of hierarchical structures of micro line array combined with fluorinated wax for anisotropic superomniphobic wettability is presented. We have achieved anisotropic and superomniphobic surface via simple two step methods, which are maskless photolithography and wax deposition. In order to prove how to provide those characteristics, SEM, contact angle measurement tool and X-ray diffraction are used. Fluorinated wax is crystalized self-assembly and it is subordinated on micro line array so that it is able to display anisotropic wettability. Understanding on anisotropic superomniphobic surface and simple fabrication method has been attracted to apply for lots of applications which range from self-cleaning surface, microfluidic chip, to directionally fluid control device, even in oily fluid.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.302-307
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• 2002

In electropolishing, the ion from the surface of the metal is eliminated by means of an electrical potential and current. Electropolishing is being generally known as a replacement for mechanical finishing. In addition to making a surface smoother, it is a more visible means of brightening, deburring, cleaning, stress-relieving and improving the physical characteristics of most metals and alloys. Therefore, the aim of the present study is to investigate the characteristic of electropolishing STS304 and A12024 in terms of current density, polishing time and electrode gap, etc.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1609-1611
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• 2013

녹색 도시 조성의 주요 요소인 수목(tree)을 대상으로 도시 대기오염 개선수준을 평가하는 연구가 활발하다. 그러나 측정을 통해 수집된 데이터는 수목의 종류와 밀도에 따라 실시간으로 직관적인 도시 대기오염 개선 정도를 판단하는 데 애로가 있다. 본 연구는 이 문제를 해결하는 데 일조하는 소프트웨어 도구를 제시한다. 본 연구에서 개발한 소프트웨어 도구는 대기환경을 개선할 지역별 대기환경측정 정보를 이용하여 3 차원 모델링과 Google Map 서비스를 매쉬업(mash-up)하여 가상으로 수목을 심고 이에 따른 도시 대기오염 개선효과를 시각화한다. 본 연구결과는 도시대기환경 개선을 위한 정책개발과 예산수립에 일조할 것이다.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.561-569
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• 2002

Laser has been called a "Quantum Machine" because of its mechanism of generation since the development on July 7,1960.by T.H.Maiman. We can now use this machine as a tool for manufacturing in industries. At present, 45kW CO2 laser, 10kW Nd:YAG laser, 6kW LD pumped YAG laser and 4kW direct diode laser facilities are available for welding a heavy steel plate of 40mm in thickness and for cutting metals at high speed of 140m/min. Laser Materials Processing is no longer a scientific curiosity but a modern tool in industries. Lasers in manufacturing sector are currently used in welding, cutting, drilling, cladding, marking, cleaning, micro-machining and forming. Recently, high power laser diode, 10kW LD pumped YAG laser, 700W fiber laser and excimer laser have been developed in the industrialized countries. As a result of large numbers of research and developments, the modem laser materials processing has been realized and used in all kinds of industries now. In the present paper, metallurgical studies on laser materials processing such as porosity formation, hot cracking and the joint performances of steels and aluminum alloys and dissimilar joint are discussed after the introduction of laser facilities and laser applications in industries such as automotive industry, electronics industry, and steel making industry. The wave towards the use of laser materials processing and its penetration into many industries has started in many countries now. Especially, development of high power/quality diode laser will be accelerate the introduction of this magnificent tool, because of the high efficiency of about 50%, long life time and compact.

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.2
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• pp.15-25
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• 1989

The purpose of this study was to supply data of resident′s participation direction about children′s playground management. In this study, use disposition and consciousness of resident about management are investigated and analyzed at the 5 children′s playground in Taegu city. The results of this study were as follows: The result of resident′s use disposition showed ; visiting frequency was "everyday or occasionally(53.5% )", and visiting purpose was "for children(47.9 %), for rest, sports, spare time(24.6%)" and visiting time was equal1y except forenoon, and staying time was "within 1 hour(73.1%)". The satisfaction about park facilities and park existence of residents′ is composed importance degree of which is convenient, manyfunction spaces, managemental of tree and facilities in order. 9.3% of residents were proposal experience about management, and concern ratio of circumferenmce showed highly "concerned answer(45.9%)" About consciousness ratio of management subject, 46.5% of residents depended on authorities leading. Wholly, recognition ratio showed low. Park administration of authorities leading and lack of resident′s concern wore thought as its problem. About experience of cleaning beautification rout children′s playground, 14.2% of residents answered "be experience". Participation type of desirous management showed highest "cleaning of fallen leaves and rubbish(22.7% )". So, residents wished to take part in such simple managements. Charge of necessary tool and cost for management showed highest "partial charge of residents (47.9% )". About participant ratio of self government activity made by residents, 75.1% of residents answered "don′t be participated". A reason of nonparticipation showed "insufficiency of place and opportunity (38.7%), deficiency of time(17.97)". Activity of initiative and existing group can be done as a fine device in future. Desirous events for children and residents showed highest "play guidence for children or meeting for aged milan(40.7% )". Therefore, it will have to consider enough about resident′s participation program for activity of use and efficient management of children′s playground.

• Journal of dental hygiene science
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• v.24 no.3
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• pp.125-133
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• 2024

Background: The management of dental plaque and the appropriate use of oral hygiene tools are crucial for oral health. With increasing interest in oral health care, various oral hygiene products are available on the market. As the most basic oral hygiene tool, the large-head toothbrush has gained significant consumer interest. This study evaluates the suitability of large-head toothbrushes as oral hygiene tools by comparing their efficacy with that of regular-sized toothbrushes. Methods: We evaluated the efficacy of large-head and regular-sized toothbrushes. The amount of dental plaque before and after brushing was measured using quantitative light-induced fluorescence digital (QLF-D) images and the plaque index (PI) in adult participants with more than 28 teeth (n=15/group). After brushing, the collected toothbrushes were rinsed 10 times in clean water, thoroughly dried, and weighed on an electronic scale. Data were analyzed using the Wilcoxon signed-rank test with SPSS Statistics Version 29.0. Results: QLF-D analysis showed a significant decrease in fluorescence intensity scores after use of a regular-sized toothbrush, whereas the scores after use of a large-head toothbrush were not significantly reduced. PI measurements indicated significant reductions in dental plaque for both head types. However, detailed analysis by tooth surface revealed that the regular-sized toothbrush significantly reduced plaque on the proximal, palatal/lingual, and labial/buccal surfaces. In contrast, the large-head toothbrush only showed significant reductions in place on the proximal and palatal/lingual surfaces, not on the labial/buccal surface. Additionally, compared to the regular-sized toothbrush, the large-head toothbrush retained more toothpaste residue despite similar cleaning efforts after brushing. Conclusion: Compared to the regular-sized toothbrush, the large-head toothbrush showed lower overall efficacy in dental plaque removal. The results of this study provide significant information regarding the use of large-head toothbrushes.

• Korean journal of food and cookery science
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• v.19 no.3
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• pp.339-353
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• 2003

The rapid increase in food borne illness outbreaks in Korea has been one of the major threats to the Nation's Health. Foodservice establishments have been identified as the major place for these outbreaks, mainly due to the lack of sanitary management and sanitary facility management practices. The purposes of the study were to develop hospital foodservice facility evaluation tools, based on the general HACCP-based standards and guidelines, for hospital food service establishments, to ensure the safety of these foodservices and to reduce the risk of food home illness. The scope of this study included: 1) an assessment of the current foodservice sanitation practices and managements for 6 general hospitals, with more than 400 beds, and 3 general hospitals, with less than 400 beds; 2) the development of foodservice establishments sanitation evaluation tools and sanitation standards, based on the HACCP system. The survey data showed varied results between the hospitals surveyed. Most of the hospital foodservice operations had many problems with ventilation and the plumbing. The total dimensional mean scores for the hospitals with more than 400 beds and less than 400 beds were 31.5 and 27.0, respectively. The highest dimension scores were for the water supply facility and lighting, with the lowest for insect and rodent control and toxic materials management. The levels of the mean scores were very low, especially for the general hospitals with less than 400 beds. These low mean scores may have arisen from critical problems within the hospital foodservice operations. The most needed facility management items for improvement were: storage shelf should be spaced 6 inches from the floor and walls, the use of three compartment sinks, utility sinks and cleaning facilities, with a floor drain for cleaning mops or liquid wastes, a ventilation hood designed to prevent dripping onto food, cooking facilities should be disassembled for washing and sanitizing, a separated hand washing sink and a sanitized food board for each area should be provided, all toxic material must have warning labels attached, and be stored in an area away from food preparation under padlock. The evaluation tool consisted of 14 dimensions, with 65 check-off items. The results of this study will provide basic facilities' guidelines to regulators, or foodservice industry personnel, wishing to build, or expend, and establish an efficient flow of food. As a result, food borne illnesses will be effectively prevented, and the Nation's health will be promoted for the development of their own sanitation standards, with a checklist for the safe production of foods.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.412-422
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• 2009

This study was conducted to assess exposure to musculoskeletal disorder(MSD) risk factors in hospital personnel who performed non-routinized work tasks. A tool ("PATH-KOSHA" version) was newly revised from PATH(Posture, Activity, Tools and Handling) method and uploaded into a personal digital assistant(PDA). The version was used, on a basis of direct-observation, to collect PATH data at the 2 hospital settings in different regions. Job analysis was performed to get various information (e.g., work and rest time, task type) as well. The data collected were visually checked for data cleaning and stored for future data analysis. A total of 1,992 PATH observations were made for 37 hospital workers. Exposure levels varied across 18 items of the MSD risk factors. The highest percent time spent on non-neutral postures was 53% for wrist deviation, followed by 47%(pinch grip), 35%(trunk posture), 23%(neck posture), and 20%(shoulder/arm posture). The highest percent time spent among hand activity level(HAL) variables was 55% for HAL-cat2 (HAL: 3.3 - <6.7). The percent time of items with respect to both loads with more than 5kg and contact stress was less than 4%. Vibration was not exposed in the study workers. Different aspects were discussed for findings. The study results showed that wrist deviation was highest in percent time spent on awkward posture while HAL-cat2 was highest in hand repetition. The study suggests that distal upper extremity posture and HAL should be primarily addressed and controlled in non-routinized work including the hospital settings.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.535-545
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• 2020

This study aims to conserve and monitor energy use in public sewage treatment plants by utilizing data from the SCADA system and by controlling the aeration rate required for maintaining effluent water quality. Power consumption in the sewage treatment process was predicted using the equipment's uptime, efficiency, and inherent power consumption. The predicted energy consumption was calibrated by measured data. Additionally, energy efficiency indicators were proposed based on statistical data for energy use, capacity, and effluent quality. In one case study, a sewage treatment plant operated via the SBR process used ~30% of energy consumed in maintaining the bioreactors and treated water tanks (included decanting pump and cleaning systems). Energy consumption analysis with the K-ECO Tool-kit was conducted for unit processing. The results showed that about 58.7% of total energy consumed was used in the preliminary and biological treatment rotating equipment such as the blower and pump. In addition, the energy consumption rate was higher to the order of 19.2% in the phosphorus removal process, 16.0% during sludge treatment, and 6.1% during disinfection and discharge. In terms of equipment energy usage, feeding and decanting pumps accounted for 40% of total energy consumed following 27% for blowers. By controlling the aeration rate based on the proposed feedback control system, the DO concentration was reduced by 56% compared pre-controls and the aeration amount decreased by 28%. The overall power consumption of the plant was reduced by 6% via aeration control.