• Korean Journal of Environmental Biology
• /
• v.32 no.3
• /
• pp.159-167
• /
• 2014

In this study, I examined the water quality and phytoplankton community in aquaculture laver farm in the southwest part of Aphae-do, South Korea, based on the young leaf stage, middle leaf stage, and adult leaf stage of laver thallus from October, 2013 to January, 2014. It was observed that the Aphae laver farm, as located in shallow waters, was found to have a serious resuspsension of the surface sediments due to physical disturbance caused by winds and tidal mixing. Such a resuspension of surface sediments coupled with nutrients supply obstructs light penetration into the sea for its huge amount of total suspended matters. As a result for this reason, it was viewed toimpedthe growth of phytoplankton was impeded as it also competes with laver to absorb the same kinds of nutrients as laver does during the laver growth period in winter. Such elements of the marine environment in Aphae laver farm are in contrast with the environment of Japan, where nutrients including dissolved inorganic nitrogen, in particular, are insufficient to cause the recent laver bad harvest, discoloration and quality degradation while large diatoms, with their higher nutrients absorption efficiency than laver, generate winter red tide. In other words, an important factor to maintain the high laver production in the southern parts of West Sea of Korea was found to be the marine environment of its laver farms where large diatoms are prevented from growing due to nutrients supply and dense seston weights from resuspended matters by physical disturbances.

• Korean Journal of Environmental Biology
• /
• v.38 no.3
• /
• pp.355-370
• /
• 2020

We conducted a field survey to analyze the ecological structure and spatial distribution of microplankton (phytoplankton and ciliates) in relation to water masses at 21 stations on the surface and chlorophyll-a maximum layers (CML) in the Northern East China Sea (nECS; 32°-33°N; 124°00'-127°30'E) from August 3 to August 6, 2019. The results showed that the water masses were divided into Chinese Coastal Waters (CCW) and the Tsushima Warm Current (TWC). The CCW showed the environmental characteristics of high temperature and low salinity, and the TWC showed high temperature and high salinity. The characteristics of the phytoplankton community in the CCW showed various community structures related to the nutrients supplied from the large rivers of the Chinese continent. However, the TWC had simple community structures because it originated near the equator and moved northward. The standing crops of phytoplankton and ciliates were very high in the CCW but showed low at the TWC. In particular, from the higher standing crops of protozoa than plant plankton at the TWC, the energy flow at the lower tropic levels caused by the microbial loop that fed on heterotrophic bacteria played an important role in the production of resource organisms. In other words, the marine ecological structure of the nECS in summer could be estimated as a bottom-up system at the CCW and a top-down system at the TWC.

• Journal of Engineering Education Research
• /
• v.4 no.1
• /
• pp.3-19
• /
• 2001

According to the acceleration of informationalization and technological renovation in new coming $21^c$, the material production elements like labor and capital as well as others which have been the resources of a country's competitive power are changing into formless knowledge-based assets like knowledge and technology. In order to meet these demands of this time, companies in developed countries are concentrating on competition and cooperation to obtain higher technology as a strategy towards becoming first-class countries in the world. Thus, the development program of human resources should focus on providing creative technical application ability. Especially, universities should develop knowledge, technology, creative problem-solving ability and realism acquired by various fields in industry where engineering is used and make it possible to perform practical tasks. As a plan for enforcement and management of this program, a certification program which evaluates the ability and accomplishments of the study of graduate students in order to manage the quality of education should be applied as soon as possible at the institute which trains engineers. In this study, among the accomplishment assessment which have been suggested as an alternative assessment method, portfolio assessment is introduced into the educational situation of engineering technological human resources to find a method of application.

• Korean Journal of Ecology and Environment
• /
• v.50 no.1
• /
• pp.126-136
• /
• 2017

We describe characteristics of diversity and distribution of oak forests on the Daegok-cheon gorge of the Southeastern Korean Peninsula, the oldest prehistoric site, in view of a sort of food resources of acorns. The $Z{\ddot{u}}rich$-Montpellier School's method was adopted for field investigation on the oak dominant stands. A total of 20 phytosociological $relev\acute{e}s$ composed of 193 taxa were analyzed by syntaxonomy and ecological flora. The Daegok-cheon's oak forests occupied 36.9% ($513,374m^2$) of the surveyed area, and its 99% ($507,677m^2$) was Quercus variabilis and Q. serrata stands. Oak forests of the Daegok-cheon gorge are a kind of regional vegetation type characterizing by the high relative net contribution degree (r-NCD) of Platycarya strobilacea and Sapium japonicum, which are an edaphic type of the xerophilous and thermophilic oak forests. The region of the Daegok-cheon petroglyphs is defined as an ecoregion with rich acorn supply and abundant water resources, and the warmer environment, which attracts prehistoric man.

• Korean Journal of Food Science and Technology
• /
• v.46 no.2
• /
• pp.262-267
• /
• 2014

To analyze the presence of microbes in organic farm produce, green chillies, lettuce, tomatoes, apples, pears, and rice were collected at 47 production sites with organic and conventional produce. Total average bacterial counts of 4.07 log CFU/g in organic green chillies, 3.71 log CFU/g in conventional green chillies, and 6.76- 6.90 log CFU/g in the both lettuce were detected. Mean bacterial counts of 4.48 log CFU/g and 2.84 log CFU/g were detected in organic and conventional pear produce, respectively. Differences in bacterial counts in tomatoes, apples, and rice in organic and conventional produce were less pronounced. Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were not detected in any produce sample. However, Bacillus cereus was detected with average counts of 1.04 log CFU/g in 11/47 (23%) conventional produce samples and 1.97 log CFU/g in 6/47 (13%) organic produce samples. Therefore, organic and conventional produce showed similar microbial prevalence patterns, and comparable safety in terms of pathogen contamination.

• Proceedings of the KAIS Fall Conference
• /
• 2005.05a
• /
• pp.297-300
• /
• 2005

1970년대 식용을 위한 양식을 목적으로 일본에서 수입된 황소개구리가 국내 하천과 호서생태계에 큰 피해를 주었으나, 최근 급속히 그 개체수가 줄어든 것으로 추정되므로 이번 연구에서는 국내에 서식하는 북미산 황소개구리의 유전자 분석을 통하여 개체동태군에 대한 유전적 연관을 조사하였다. 이를 위하여 전라남도 지역에서 서식하는 황소개구리를 채집하여 이미 발표된 북미산 황소개구리와 미토콘드리아 ND1/tRNA 유전자 1215bp의 염기서열을 비교, 분석하였다. 북미산과 비교하였을 때 조사한 국내 서식 개체 모두에게 ND1/tRNA 유전자 1개 위치에서 염기변화가 발견되었으나 이는 도입 개체군의 유전자인지 국내 특이변이가 진행된 것인지 확실하지 않다. 또한 조사한 개체 일부에서 유전자 염기서열의 6위치에서의 변이가 발견되었으나 국내 서식 황소개구리는 미국산 황소개구리와의 유전적 차이가 거의 없으며, Kimura-2-parameter 분석결과 국내 서식 황소개구리 개체 내에서 $98.7\%\~100\%$의 높은 유사성을 보여 종내 유전적 차이가 거의 없는 것으로 보인다. Neighbor-Joining과 Maximum Parsimony 분석 결과, cluster를 이루는 개체군의 차이를 보였으므로 개체들이 분화되어 나온 시점과 위치가 다른 것으로 확인되었지만 장흥, 영암, 고흥의 개체가 국내 도입시기의 개체군에 속하며 광주, 남평 지역의 개체군이 고흥의 한 개체로부터 분화되어 나왔음을 추정할 수 있다. 이러한 결과로부터 국내에 서식하는 황소개구리가 도입 후 지역 특이적 분화가 일어났다고 결정하기는 무리가 있으며, 이와 같이 유전적 유전도가 높은 개체들간의 교배에 따른 유전적유전적 다양성의 감소가 최근에 관찰되는 국내산 황소개구리의 급격한 감소원인들 중의 하나일 가능성을 시사한다.년도) 18,756, 2045(년도) 22,595, 시장점유율 증가로 인한 수출액 증가분 누적(억원) : 2015(년도) 3,411, 2025(년도) 8,847, 2035(년도) 14,433, 2045(년도) 18,005 또한 시나리오 비교평가를 실시하여 본 결과, 본 연구에서 정의한 순편익 누적(Cumulative Net Profit) 변수를 적용하면 현재 연구비 추세 대비 $30\%$ 까지 연구비를 증가 시키는 것이 효율적임을 알 수 있었다.성, 생산 용이성, 제품 디자인의 우수한 정도가 a=0.01 수준 하에서 유의적으로 추정되었다. 이들 변수들 중에서 품질경쟁력에 가장 큰 영향을 미치는 측정변수는 제품의 기본 성능, 수명(내구성), 신뢰성, 제품 디자인의 순서로 추정되었다. 이것은 한국 제조업이 아직 산업 디자인이 품질경쟁력에 크게 영향을 미치는 성숙단계에 이르지 못하였음을 의미한다. (2) 제품 디자인에게 영향을 끼치는 유의적인 변수는 연구개발력, 연구개발투자 수준, 혁신활동 수준(5S, TPM, 6Sigma 운동, QC 등)이며, 제품 디자인은 우선 품질경쟁력을 높여 간접적으로 고객만족과 고객 충성을 유발하는 것으로 추정되었다. 상기의 분석결과로부터, 본 연구는 다음과 같은 정책적 함의를 도출하였다. 첫째, 신상품 개발과 혁신을 위한 포괄적인 연구개발 프로젝트를 품질 경쟁력의 주요 결정요인(제품의 기본성능, 신뢰성, 수명(내구성) 및 제품 디자인)과 연계하여 추진해야 할 것이다. 둘째, 기업은 디자인 경영 마인드 제고와 디자인 전문인력 양성을, 대학은 디자인 현장 업무를 통하여 창의력 증진과 기획 및 마케팅 능력 교육을, 정부는 디자인 기술개발 및 디자인 교육지원의 강화를 통하여 각각 디자인 경쟁력$\rightarrow$품질경쟁력을 제고시켜야 할 것이

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.3
• /
• pp.51-58
• /
• 2008

Development of a new design guide which is based on empirical-mechanistic concept for pavement design is in action. It is called AASHTO 2002 Design Guide in USA and the KPRP(Korean Pavement Research Project) in Korea. The material characteristic of hot mix asphalt is a key role in the design guide. Therefore it is urgent to get a proper materials database, especially the dynamic modulus of hot mix asphalt. In this research, dynamic modulus test, which is based on aged asphalt binder, has been carried out and proposed the predicted equation of dynamic modulus. Nine different hot mix asphalt with three different asphalt binder have been used for the dynamic modulus test. Short-term aging, which is covers the time for the production of asphalt plant, transportation, lay-down, and compaction, can be simulated at $135^{\circ}C$ with 2 hour curing. Long-term aging has been carried out for a performance period of asphalt pavement. The dynamic modulus of asphalt pavement increases with aging time. As the nominal aggregate size increases, the change of dynamic modulus is not big.

• Journal of Energy Engineering
• /
• v.26 no.3
• /
• pp.105-112
• /
• 2017

A lot of piping systems have been used from nuclear power systems to water supply systems. The maintenance of the piping systems is needed to ensure proper operation of the piping systems. Failure of the large pipe systems especially such as KDHC(Korea District Heating Corporation) can be a matter directly related to the enterprise productivity and profitability. It can also lead to very important issues in promoting public safety and convenience. Therefore a method of quick and safety repairs have been emerged as the most important problem. In this study, freezing seal isolation method using liquid nitrogen cryogenic refrigerant was developed for the maintenance of a pre insulated heat transport pipe of KDHC with a diameter of 300 mm. In this study, by employing computational analysis techniques we performed the flow and heat transfer analysis for the targeted pre insulated heat transfer pipe and freezing seal jacket(ice-Plug) and have selected for optimal system. The detailed design model based on the results of the computational analysis finally was produced. A laboratory-scale test apparatus were designed and the freezing seal isolation self-test carried out. Also the performance assessment tests in the test bed of KDHC were carried out for on-site application.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.5
• /
• pp.194-203
• /
• 2008

Construction Research and Development (R & D) projects have been begun with the investment of 1.2 billions in 1994 and have been reached to 30 billions in 2004. During this ten-year period, a total of investment for construction R&D amounts to 125.7 billions (Total 418 construction R&D projects). However, the results of each R&D project could not apply to real construction site because each project has been performed by a small size (0.5 billions). In addition to those, the social interest on the construction R&D projects has not been received and those importance has not been recognized. Especially, there aren't still standardized methodologies or weighted measurement data for evaluating research performance of the construction R&D projects up to now. The construction R&D projects has been Invested on the basis of an annual technology demand survey rather than the research performance outcome. Therefore, it is important to establish a qualitative performance measurement model for evaluating construction R&D projects. This paper proposes a new research methodology for analyzing the performance measurement of the construction R&D projects. First of all, the Balanced Score Card (BSC) is used to evaluate the construction STAR technologies selected in this research. The performance items of BSC has been modified as four criteria such as "productivity, "knowledge accumulation," "training of students," and "welfare." The new research methodology developed in this paper is expected to use in establishing resonable construction R&D budget in the future.

• Proceedings of the Safety Management and Science Conference
• /
• 2013.11a
• /
• pp.483-497
• /
• 2013

현대사회가 발전 할수록 대량산업화와 도시화가 심화되어 건축물의 초고층화 및 대형화가 증가하고 있으며, 안전적인 건축물 보다는 건물 및 제조사업장의 시각적인 디자인에 치우쳐 화재하중이 높은 건축자재의 내 외장재 및 고급스러운 장식물을 사용함으로써 그 위험뿐 만 아니라 화재발생시 대규모 인명 및 재산상의 피해를 가져오게 된다. 그리고 제조사업장화재는 화재로 인한 직접적인 손실 즉 물적 손실은 물론 생산중단으로 인한 간접적인 손실은 실로 측정하기가 어렵다. 지금까지 발생한 제조사업장화재의 발화요인별 분석은 부주의, 전기적, 미상 순으로 인한 화재가 가장 많고 발화열원은 작동기기, 담뱃불(라이터), 마찰 전도 복사등이 주요 원인이 되고 있고 대형화제 취약시설로는 공장 및 창고로 나타나고 있다. 소방방재청의 통계자료를 살펴보면 2012년 화재 발생현황 중 발화요인에 대한 화재별 장소 건수를 검토 한 결과 비주거의 화재발생 16,009건 중 5,758건으로 (36%)부주의이고, 주거에도 화재발생 10,715건 중 5,560건으로 51.9%의 부주의로 가장 높은 것으로 나타났다. 그러므로 제조사업장의 사소한 부주의로 발생하는 화재를 예방하기 위해서는 소방안전관리자의 처우개선과 기업활동규제완화의 겸직 허용을 재검토 하여야 하며, 소방안전관라자의 실무능력 강화를 위한 소방안전관리 실무교육과정을 이론적 교육 보다는 현장 실습위주로 할 필요가 있다. 이를 위해서는 소방안전관리자에 대한 법정 실무교육 횟수를 확대하여 현행 2년에 1회 에서 1년에 1회로 하고, 실무교육에 있어서도 우수송방안전관리 업체를 선정하여 화재예방에 대한 구체적인 업무를 활성화 하고, 문제 발생요소들을 분석하여 실습을 통한 소방안전관리자의 실무교육을 실시해야 할 것이다. 이러한 전문 소방안전관리자로 소방대상물의 소방교육 및 훈련을 성실히 수행 해야 할 것 이다. 한순간의 부주의로 인하여 화재가 발생하면 돌이킬 수 없는 수백명의 생명을 앗아가고, 수백억원대의 재산피해를 줄이기 위해서는 소방안전관리자의 역량을 넓히고 화재예방 업무를 최우선적으로 수행해야 할 것이다. 화재예방을 위해 소방안전관리자의 업무개선 및 전문교육을 활성화 하여 업무능력을 향상 시켜 화재발생시 초기진압에 신속하고 정확하게 대처해야 한다는 것이 전문적인 화재예방 대책 일 것이다.