• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.945-951
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• 2012

A water emulsion fuel can be used to reduce soot and NOx emissions simultaneously because it has a lower combustion temperature and better fuel atomization owing to the evaporative latent heat and microexplosion of water. Moreover, it can be used without making special modifications to conventional diesel engines. Therefore, this fuel has attracted considerable research attention. In addition, lower-grade fuels are being considered for use in conventional engines because of an increase in oil prices. In this study, we investigated the combustion and exhaust characteristics of MDO (marine diesel oil), which has a lower grade than common diesel oil, and ME (MDO water emulsion) under various test conditions in an automotive diesel engine.

• Convergence Security Journal
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• v.13 no.2
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• pp.101-109
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• 2013

Problem Based Learning(PBL) is one of effective teaching-learning strategy for enhancing military students' motivation, comparing with the other study method. After monitoring military student classes, we conclude that PBL can enhance the effectiveness of learning in War history case study education and finds merits; PBL assists students to play a more active role in the class, induces students to solve problems independently, and makes the learning military situation real case study. The case study is common in social sciences and life sciences. Case studies may be descriptive or explanatory. It is good for War history education. The demerit of PBL is a costly method as students should spend more time and institutions should provide more manpower and materials. This study suggests that more empirical researches on alternative teaching methods, including PBL, to a lecture in War history education.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.175-176
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• 2003

쌀의 연간 생산량은 재배기술의 발달과 더블어 500만톤 이상을 꾸준히 유지해 오고 있는 반면에 식생활패턴은 점차 인스턴트화 되고 육류소비가 증가함으로써 1인당 소비량이 1990년 119.6kg에서 2002 년 87.0kg으로 급격히 감소하는 추세를 보이고 있다. 이러한 현상은 재고누적으로 이어져 2002년말 기준으로 1,190만석의 재고가 발생되고 있으며, 더욱이 WTO체제하에서 쌀시장 개방압력이 강화되고 있는 실정으로 앞으로 재고문제는 더욱 심화될 것으로 전망되고 있다. 이렇게 쌀이 남아도는 현실에서 국내 유통미의 품위는 싸라기 및 분상질립, 피해립, 이물 등 불완전립의 비율이 매우 높아 일본산이나 미국산에 비해 품질이 현저히 떨어지고 있어 고품질 가공을 통한 차별화가 시급히 요청되고 있는 실정이다. 따라서 본 연구에서는 최근 고품질 쌀 가공을 위해 설치 운영되고 있는 완전미 가공시설을 중심으로 완전미 가공기계장치의 구성 실태 및 제품의 품위 등을 조사분석하여 완전미 가공 기계장치의 개량요인을 도출하고, 이를 토대로 기계장치를 보완하기 위한 기초자료를 얻고자 하였으며, 그 결과를 요약하면 다음과 같다. 현재 보급되어 있는 완전미 가공시설의 구성형태는 기존 미곡가공시설에 홈선별기를 1대를 추가 설치한 제 I유형, 색채선별기1대 + 홈선별기 1대를 추가설치한 제II유형, 색채선별기 1대+입선별기 (개조) 1대를 추가한 제III유형으로 크게 나누어지고 있다. 이들 시설의 도정능력은 백미 가공시에는 I, II, III유형에서 각각 24.0, 27.7, 24.0톤으로 높았던 반면에 완전미 가공시에는 각각 3.1, 5,3, 4.5톤으로 처리능력이 크게 떨어지는 것으로 나타났다. 가공수율면에서는 일반백미로 가공시 72.0% 수준이었으나 완전미로 가공시에는 64.3%로 7.7%의 수율 감소를 가져왔지만 완전립률이 일반백미로 가공시 I, II, III유형에서 각각 89.08, 91.57, 88.00% 에서 완전미로 가공시에는 각각 98.02, 98.43, 97.78% 높아져 품질이 크게 향상되었다. 따라서 완전미 가공시설을 도입할 경우 쌀의 외관품질을 크게 높일수 있는 것으로 나타났다. 또 현재의 완전미 가공시설에 있어서 개량이 필요한 부분은 미숙립 등을 효율적으로 제거해 가공효율을 높이기 위해서는 입선별기의 개량이 요구되었으며, 홈선별기의 경우에는 선별정도는 문제가 없었으나 처리능력의 향상이 필요한 것으로 나타났다. 따라서 완전미 가공효율을 높이기 위한 선별기 개량연구를 계속 수행중에 있다.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.237-243
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• 2011

As the effluent quality standard of the municipal wastewater treatment plant (MWTP) has been strengthened, the treatment of the recycle water containing high concentration of ammonium nitrogen has been considered as one of retrofit methods for upgrading the exising MWTPs. In this study, nitritation, economic nitrogen removal process, was induced by laboratory-scale reactor at the $35^{\circ}C$, $20^{\circ}C$, and $10^{\circ}C$ temperature conditions using anaerobic digester supernatant. The stable nitritation was achieved over $20^{\circ}C$, but nitrification was induced at $10^{\circ}C$. It means that the nitritation was affected by SRT and temperature. SRT, demanded for nitritation, is changed according to the temperature. Therefore, it is considered that SRT and temperature are important factors in nitritation. Also, it is approved that inducing the ammonium nitrogen removal and the nitritation are more beneficial over $20^{\circ}C$. The conclusion of this study can be used for the important basic reference when nitritation process is applied for MWTPs.

• Korean Journal of Construction Engineering and Management
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• v.24 no.3
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• pp.31-41
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• 2023

This study is a study to develop a configuration management methodology for efficient and systematic management in the event of configuration changes such as deformation, explosion, and remodeling of launch vehicle development test facilities, which are emerging as important national facilities in the era of full-scale space competition. Through the analysis of international standards for configuration management, a configuration management process framework to be applied to launch vehicle development test facilities is extracted, a survey was conducted on experts who performed life cycle engineering of launch vehicle development test facilities, and a configuration management methodology optimized for operation/management of domestic launch vehicle development test facilities was proposed. Identify the configuration for launch vehicle development test facilities, the configuration management manager, configuration management organization, and configuration management board approve/process the configuration changes, and after construction is completed according to design requirements, launch vehicle development test facilities try to manage the configuration in a controlled state.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.625-637
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• 2020

In order to decide the naval ship weapon system acquisition for national policy/market economy activities, the decision makers can determine policy based on current technology level/concentration/utilization. For this, the decision makers apply the major common technology field analysis using patents data. As a method for collecting patent data, we can collect patent data of domestic mobile carriers through the Korea Intellectual Property Rights Information System of Korean Intellectual Property Office. As a result, we collected 14,964 patents/352 International Patent Classification(IPC) types. Based on these data, we performed three analysis processes (SNA, PCA, ARIMA, Text Mining) and got each result from extracting 58 IPC types of SNA and 7 IPC types of PCA. Based on the analysis results, we have confirmed that 7 IPC(B63B, H01M, F03D, B01D, H02K, B23K, H01H) types are the Major Common Technology Distribution of domestic Defense Companies.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.378-385
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• 1994

Interspecific somatic hybrids were obtained by protoplast fusion between Pleurotus ostreatus and Pleurotus sajor-caju. The fusion products between incompatible strains did not form clamp connections. Fruiting body of the clampless fusants was induced by light-dark cycle on saw-dust-rice bran substrate in glass bottles. Out of them, seven somatic hybrids produced fruiting bodies of intermediate morphology of the two species. Light and low temperature were the initiating factors for the development of clamped hyphae from the clampless mycelial colonies. All of these basidiocarps had clamp connections. Eight fusants from the six crosses were analysed with the segregation of genetic characters by random spore isolates. In the three combinations, unexpected alleles were shown. Somatic hybrid between P188 (P. ostreatus 2-1 + P. sajor-caju 2-53) and P. florida 2-3 by triple cross produced fruiting bodies similar to those of fusant between P. ostreatus and P. florida. All the genetic charaters from the three strains were shown to segregate and recombine.

• Land and Housing Review
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• v.5 no.4
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• pp.225-234
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• 2014

Because of their nature as public facilities, demands that former military facilities be utilized for the public welfare are increasing, thereby leading to an increase in cases in which these military facilities are reestablished as parks. Cases in which former military bases were reestablished as public parks were analyzed; as a result, several implications were derived. First, the objectives of public park projects should be examined from the perspective of the concept of urban regeneration and regional revitalization. Moreover, it is necessary that profits are yielded and that regional identity and history are reproduced through reusing existing facilities as much as possible rather than entirely remodeling former military sites. As parks become larger in size, bases should be reorganized into complexes rather than single facilities or programs. It is also necessary that parks be established in stages considering the enormous expenses required for building public parks. Consequently, because the special characteristics of military facilities can lead to insufficient on-site investigation in the process of establishing parks, thereby incurring a vast amount of costs for design adjustment and contamination disposal, this should be considered in advance. A method of delegating the development rights to partial sites to private businesses and supplementing the costs of park establishment and maintenance with development benefits should be examined. In addition, given that there are various interests and stakes in former military bases, a method of operating a public-private cooperative decision-making organization during project execution should be considered. Finally, policies related to urban parks need to be improved in order to raise funds, expand profitable businesses, facilitate social services and sponsorship, and encourage the participation of trusts and non-profit organizations in park operation and management.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.537-544
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• 2018

A national comprehensive aviation test center is being constructed for the purpose of flight tests for development and modification of aircraft or flight inspections for the development of navaids. Flight testing is a high-risk task, so strict risk management processes are required prior to operation. In addition, since the flight test center is subject to the airdrome regulations under the current law, the introduction of the safety management system will enhance safety as usual in ordinary airports. The establishment of a safety management system based on ICAO criteria is an optimal means of ensuring safe and effective operation of the test center and may mitigate the risks that may arise during flight testing. This paper focuses on risk assessment and mitigation required for safety management at the flight test center. We conducted risk assessments on the flight hazards identified in the previous study. Then the high risk group of hazards were selected and risk mitigation techniques such as avoidance, reduction, acceptance, and control were applied.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1093-1101
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• 2000

The object of this study was to develop new BNR process using fixed-biofilm which could be applied to retrofit the existing wastewater treatment plant or to introduce as tertiary treatment plant. To achieve complete denitrification from typical raw sewage in Korea, external carbon source must be supplied because $SCOD_{cr}/T-N(NH_4{^+}-N+NOx-N)$of raw sewage was lower than other countries. In this study, the ratio of $SCOD_{cr}/NH_4{^+}-N$ was 2.49 and the influent $NH_4{^+}$-N concentration during the experimental period was varied from 25 to 37 mg/L. To enhance nitrogen removal from the sewage, the two processes using fixed biofilm were adopted as R-Hanoxic/mid.settler/aerobic/anoxic/ aerobic) and R-2(aerobic/mid.settlerlanoxic/anoxic/aerobic), respectively. In the comparison of $NH_4{^+}$-N, T-N effluent quality and T-N removal efficiency in both processes without external carbon source, R-1 process was better than R-2 process for nitrogen removal from raw sewage. With respect to $SCOD_{cr}$/NOx-N ratio and total nitrogen removal in each anoxic reactor of two processes, R-1's was more effective than R-2's for distributing organic matters of raw sewage. In the both processes using fixed biofilm, the amount of required alkalinity to remove unit $NH_4{^+}$-N were 5.18 and 5.76($g{\cdot}CaCO_3/g{\cdot}NH_4{^+}-N_{removed}$), respectively and were lower than activated sludge BNR process(7.14).