• Journal of Educational Research in Mathematics
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• v.23 no.4
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• pp.567-584
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• 2013

In school mathematics, the concept of continuous functions has been intuitively taught. Many researches reported that many students identified the continuity of function with the connectedness of the graphs. Several researchers proposed some ideas which are enhancing the formal aspects of the definition as alternative. We analysed the historical developments of the concept of continuous functions and drew pedagogical implications for the intuitive teaching of continuous functions from the result of analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.89-92
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• 2006

수소에너지는 화석연료 사용의 증가로 인한 환경오염 및 자원고갈의 문제점을 해결해 줄 수 있는 미래의 청정한 에너지이다. 현재 주 에너지원인 화석연료의 사용에 의하여 배출된 오염물질이 지구온난화와 같은 문제점들을 일으킨다. 이러한 문제점들을 없애줄 수 있는 대안 중 하나가 수소에너지이다. 수소에너지는 자원이 풍부하며 연소시에 오염물질이 배출되지 않는 장점이 있다. 수소에너지는 수소를 연소시켜서 얻는 에너지로써, 수소를 태우면 같은 무게의 가솔린 보다 3배나 많은 에너지를 방출한다. 수소를 생산하는 방법 중 가장 이상적인 방법은 물을 분해하는 방법이다. 그러나 이 방법은 수소를 대량으로 생산하기에는 아직 기술에 대한 확보가 되어있질 않으며, 경제성도 떨어진다는 단점이 있다. 현재 많이 쓰이는 방법 중 탄화수소류의 메탄을 수증기 개질하는 방법이 있다. 메탄 수증기 개질방법은 환경오염물질인 CO나 $CO_2$를 배출한다는 것과 높은 열원이 필요하다 본 연구에서는 C-H결합에너지가 낮아 메탄보다 분해하기 쉬운 부탄의 직접분해로 수소를 생산하고자 한다. 부탄 직접분해는 환경오염물질인 CO나 $CO_2$가 발생되지 않는 장점이 있다. 부탄 분해반응은 $500{\sim}1100^{\circ}C$의 범위에서 이루어 졌으며, 촉매는 탄소계인 카본블랙을 사용하였고, 촉매의 성능을 비교하기 위하여 열분해반응이 동시에 수행되었다.

• The Journal of Korean society of community based occupational therapy
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• v.2 no.2
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• pp.1-13
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• 2012

Objective : The purpose of this study was to understand the game world experience and peer interaction of students with disabilities in the community. Method : In this study, Giorgi's phenomenological method was used to understand the game world experience and peer interaction of two students with disabilities in the community. The data collection about the situation and the context of the subjects was conducted over three times of interviews, until no new data. Meaning units through the four steps for Giorgi's scientific phenomenology were analyzed in the context of the overall data. Result : Two students with disabilities in the community had to spend time at home with physical limitation and alienation, and their leisure activities was mainly using the computer and television. Restrictions of leisure activities wad the cause of difficulties of social accessibility, and they need the correct thinking and self-control in the use of the time. Due to the game for fun, they have no interact with peers. On the other hand, most of conversation about the game were with families. Conclusion : Students with disabilities had a physical and psychological difficulties were feeling pleasure through the game. They need the correct thinking and self-control in the use of the time, and need an alternative solution for a reckless game use.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.1 s.8
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• pp.149-155
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• 2003

The reason of source for a tragic death by the occurrence of an event is $\ulcorner$unobservant of safety rule,$\lrcorner$ $\ulcorner$negligence of staff,$\lrcorner$ $\ulcorner$deficiency of responsibility$\lrcorner$ and $\ulcorner$deficiency of safety value$\lrcorner$ and for certain reason that is insufficiency of space for safety education also think little of a people, unobservant of safety rule, selfishness and so on. It makes new and specific plan that is simulation room before I compare the inside and outside of the country for a nation the reform of consciousness. Next, go ahead with a plan for about safety-simulation room. The Government can support to plan if it make a proposal to center of Government. It should be make a people of safety system, and it build the safety-simulation room $1{\sim}2$ in the city or county. And, the city cannot build the big safety-simulation room the reason are size of building and money. Accordingly, it will be make a system and installation for different type of safety-simulation room for about calamity, disaster and different type of accident in Korea. It must be build the building of space that should be make a space of knowledge and information by many books and media, develop of education program from life-safety.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.1-5
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• 2015

Lactic acid, the most widely occurring hydroxy-carboxylic acid, has traditionally been used as food, cosmetic, pharmaceutical, and chemical industries. Even though it has tremendous potential for large scale production and use in a wide variety of applications, high cost lactic acid materials are primarily problems. Lactic acid can be obtained on either by fermentation or chemical synthesis. In recent years, the fermentation approach has become more successful because of the increasing market demand for naturally produced lactic acid. Generally, lactic acid was produced from pure starch or from glucose. As an alternative, biomass which is the most abundant renewable resources on earth have been considered for conversion to readily utilizable hydrolysate. In this study, we conducted the fermentation method to produce L(+)-lactic acid production from pretreated hydrolysate was investigated by Lactobacillus rhamnosus ATCC 10863. The hydrolysate was obtained from pretreatment process of biomass using Ammonia percolation process (AP) followed by enzymatic hydrolysis. In order to effectively enhance lactic acid conversion and product yield, controlled medium, temperature, glucose concentration was conducted under pure glucose conditions. The optimum conditions of lactic acid production was investigated and compared with those of hydrolysate.

• Spatial Information Research
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• v.10 no.1
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• pp.45-59
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• 2002

The author argues that the current Government Information System for river water quality appears to be non-user friendly due to lack of the cartographic representation for the field monitoring data. Acknowledging these constraints, an operational, user-friendly information system has been developed by combining Internet technology with GIS. A digital map for water quality has been generated by overlaying monitoring data on existing cartographic data such as road, topography and administrative boundary etc. A user interface was designed to address the need to querry the large spatial databases by non-GIS and non-environmental experts. The system has been checked experimentally and enabled the users to querry data required simply. And detailed visual maps for water quality can be generated over large areas quickly and easily. A visual mapping system for water quality was developed by reframing the monitoring data as graphic symbols and it was ideally suited to exploring area-wide water quality at a user-friendly manner due to extensibility and scalability along the various survey points. This system based on Web GIS could be accessed anywhere if internet is available. It would play a crucial role in improving the quality of public information service if it is operationally introduced into the Government since the highly user-friendly interface provides a completely new means for disseminating information far water pollution in a visual and interactive manner to the general public.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.118-127
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• 2005

The comparison of water balance and nutrient loading from paddy field with different irrigation management were carried out during 1999 ${\sim}$ 2002 at two different sites; one is irrigated with groundwater and the other is irrigated with surface water. For the surface water irrigated paddy field, irrigation was performed continuously during growing season. Whereas, initial irrigation with groundwater was applied during initial growing season, and the ponded water depth was maintained by natural precipitation since initial irrigation. The runoff frequency of groundwater irrigated paddy field was less than that of surface water irrigated paddy field. The nutrient concentration of ponded water was high by fertilization at early cultural periods, so reducing surface drainage during fertilization period can reduce nutrient loading from paddy fields. Amount of irrigation water to surface water irrigated paddy field was higher than to groundwater irrigated paddy field and evapotranspiration was similar because it is influenced by climate. Overall input in and output from paddy field irrigated with goundwater were less than that with surface water. This study indicate that efficient water management can reduce surface drainage outflow, save water, and protect water quality. It might be important BMPs for paddy field.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.2
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• pp.242-264
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• 2016

Tourism is a major sector of the national and regional economy in Southeast Asia endowed with rich natural environment and a variety of cultural and historical heritages. Tourism has been recognized as the industry without chimneys. However, as tourism sector is getting larger and being globally standardized, various problems such as environmental degradation as well as profits leakage from locals have been gradually aggravated. Against negative impacts from massive tourism various efforts have been tried and community-based ecotourism(CBET), seeking environmental conservation and community development at the same time, has emerged as a noteworthy alternative. By comparing the two cases of CBET in Indonesia and Cambodia, this paper aims to review the current status and future challenges of community development through ecotourism in Southeast Asia's rural villages. In the concrete, this paper analyses in-depth on case of JED(the village ecotourism network) in Bali, Indonesia and CBET project in Ramsar wetland reserves of Steung Treng province, Cambodia and founds out the possibility and main obstacles of community developmental strategy through CBET. Both cases have proven the positive outcomes in terms of environmental protection, local people's awareness improvement, and direct/indirect economic gain from CBET project. However, there are significant, but differentiated limitations in management capacities and stabilities of internal governance of two villages. Both villages are still in need of brisk networks with and assistance from the outside. In the conclusion part, this paper suggests CBET development program in Southeast Asia through Korea's social enterprises as one of the possible ODA programs(in tourism sector).

• Food Science and Preservation
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• v.20 no.4
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• pp.482-487
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• 2013

The quality characteristics of commercial fermented vinegars made with different ingredients were compared. The pH levels of the persimmon, fig, and brewing and rice vinegars were 3.60, 3.37, and 2.62, respectively. The total acid contents of the brewing, apple, and plum vinegars ranged from 6.33 to 6.57%. The free amino acid contents were detected in the following order: brewing vinegar (521.05 mg/100 g) > fig vinegar (358.89 mg/100 g) > persimmon vinegar (353.02 mg/100 g) > rice vinegar (122.31 mg/100 g) > plum vinegar (103.52 mg/100 g). The free amino acid contents of the commercial fermented vinegars were 56.85~358.89 mg/100 g, and their gamma-aminobutyric acid (GABA) contents, 0.21~27.22 mg/100 g. In particular, the GABA content of the fig vinegar was 1.3- to 100-fold higher than those of the other vinegars. The total polyphenol compound and total flavonoid contents were detected in the following order: persimmon vinegar > fig vinegar > brewing vinegar > rice vinegar. Hence, the results of this study can provide a new alternative for making functional vinegars containing organic acid and GABA.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.46-46
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• 2015

강우가 지역별 계절별로 편중되어 있는 우리나라는 수자원의 안정적인 확보와 이용을 위해 다양한 형태의 댐을 건설하여 운영하고 있다. 그러나 대부분의 댐건설을 통해 형성된 저수지들은 탁수 장기화 및 녹조 발생 등의 환경, 생태적인 문제를 겪고 있으며, 그에 따른 사회적 우려로 인해 신규댐 건설을 통한 수자원확보는 더 이상 어려운 실정이다. 이러한 문제에 대응하기 위한 대안으로 기존 댐 저수지들(안동호-임하호)의 구조적 연계운영방안이 진행되고 있다. 본 연구의 목적은 2차원 CE-QUAL-W2모형을 활용하여 안동호와 임하호의 구조적 연결에 따른 탁수의 이동과 각 저수지 내에서의 유동 변화를 해석하는데 있다. 저수지 연계 시나리오는 EL. 138 m 위치에 길이 2 km, 직경 5.5 m 의 콘크리트관(마찰계수 0.05)이 안동호 좌안인 임동면 마리와 임하호 우안 망천리를 연결하는 것으로 가정하였다. 모델의 보정은 실측자료가 풍부한 2006년도 수문사상을 대상으로, 개별 저수지에 대해 수행하였고, 탁수 유동 시나리오 해석은 임하호에 심각한 탁수장기화 문제가 발생했던 2002년을 대상으로 댐 연계 탁수모의를 수행하였다. 안동호와 임하호의 댐 앞에서 모의값과 실측값을 오차를 분석한 결과 탁수예측오차는 AME 0.5~24 mg/L, RMSE 0.7~30.2mg/L의 범위로 비교적 실측값을 잘 반영한 것으로 나타났다. 임하댐의 경우 탁수층의 위치와 두께, 그리고 최고 탁도값을 적절히 재현 하였지만, 안동댐은 최고 탁도값 예측에서 다소 오차가 발생하는 것으로 나타났다. 안동호와 임하호 단독 운영시와 연계 운영시의 탁수변화 파악을 위해 초기 홍수사상이 발생한 8월 이후부터 저수지내의 TSS농도 분포를 비교하였다. 안동호의 경우 댐앞지점의 탁수분포는 수온성층구조에 영향을 받아, 단독 운영시(EL. 130 m)보다 연계운영시(EL. 140 m)에 탁수의 중심이 높은 위치에 형성되었다. 단독 운영시 10월 이후에 전도현상으로 인해 침강되지 않은 잔류 탁수층이 저수지 하부로 확산되었지만, 연계 운영시에는 재부상 되어 상층으로 확산되는 것으로 모의되었다. 또한 연계운영시 유량이동으로 인해 안동호의 탁수 댐앞 도달시간이 짧아지는 것으로 나타났다. 반면 임하호는 연계 운영시 안동댐으로 유출이 생기면서 중층에서 탁수량이 저감되는 것으로 모의되었다. 저수지 내 탁수량 분석을 위해 SS 15 mg/L 이상의 잔류 탁수량을 분석한 결과, 연계운영시 안동호의 평균 잔류탁수량 비율은 11.8% 증가, 임하호의 경우 11.7% 감소하였다. 또한, 탁수의 댐하류 방류일수도 SS 15 mg/L 기준 임하호 9일 저감, 안동호는 70일 증가하여 임하호의 탁수가 안동호의 탁수 장기화에 영향을 주는 것으로 나타났다.