• International Journal of Naval Architecture and Ocean Engineering
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• 제2권1호
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• pp.24-33
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• 2010

Design of a Pump Jet Propulsor (PJP) was undertaken for an underwater body with axisymmetric configuration using axial/low compressor design techniques supported by Computational Fluid Dynamics (CFD) analysis for performance prediction. Experimental evaluation of the PJP was earned out through experiments in a Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminum alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle m water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed.

• 대한지역사회영양학회지
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• 제19권1호
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• pp.60-70
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• 2014

The purpose of the study was to examine job satisfaction, work performance, work satisfaction, perceived needs and self-evaluation of knowledge and skills of nutrition teachers. Survey questionnaire was administered to 106 nutrition teachers in schools of Gyeonggi area. Subjects were categorized into high- or low-job satisfaction group, and study variables were examined by job satisfaction group. Overall job satisfaction was high, with a mean score of 14.9 out of 20. High-job satisfaction group had more favorable perception regarding human relations and workplace atmosphere compared to the counterparts (p < 0.001). Work performance, examined by 12 items, was not significantly different between the two groups. However, satisfaction regarding specific work of nutrition teachers was significantly different by job satisfaction (p < 0.001). High-job satisfaction group responded that they had more knowledge and skills in areas such as food purchase management, food sanitation and safety management, equipment and facility management, nutrition education, nutrition counseling (p < 0.01), and general management & marketing (p < 0.05). High-job satisfaction group also indicated that nutrition teachers need to have more knowledge and skills than the counterparts, regarding food purchase management (p < 0.001), nutrition education (p < 0.01), nutrition counseling, general management and marketing, and teaching practices (p < 0.05). In addition, study results showed significant positive correlations among study variables. This study suggested that job satisfaction of nutrition teachers might be increased by having favorable human relations and workplace atmosphere, increasing satisfaction with specific work of nutrition teachers, and by increasing the knowledge and skills required for the work of nutrition teachers.

• 한국물환경학회지
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• 제29권3호
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• pp.354-364
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• 2013

The performance of the stormwater wetlands can be significantly influenced by antecedent stormwater in storage at the commencement of a stormevent. As inflows are intermittent and stochastic in nature, the evaluation of the treatment efficiency of a stormwater wetland should be considered by runoff capture and water treatment characteristics during interevent periods. In this study, analytical probabilistic model is applied to identity runoff capture rate and treatment efficiency of the stormwater wetland. To achieve this, continuous rainfall data recorded in Busan for 31 years has been analyzed to derive the runoff capture rate, and 1st order kinetic decay constants ($k_V$, 1/d) are calculated from regression analysis to identify pollutants removal during interevent periods. The results show that about 60.9% of annual average runoff is captured through the stormwater wetland. The annual average treatment efficiencies of SS, BOD, COD, TN and TP is about 11.4, 8.9, 9.8, 4.3 and 9.6%, respectively. The analytical model has been compared with the numerical model and it shows that analytical model is valid. Performance evaluation methods developed in this study has the advantages of considering characteristics of rainfall-runoff, facility type and pollutant removal.

• 한국물환경학회지
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• 제34권6호
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• pp.569-578
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• 2018

To minimize the negative alterations in hydrologic and water quality environment in urban areas due to urbanization, Low Impact Development (LID) techniques are actively applied. In Korea, LID facilities are classified as Non-point Pollution Reduction Facilities (NPRFs), and therefore they are evaluated using the performance evaluation method for NPRFs. However, while LID facilities are generally installed in small, distributed configuration and mainly work with the infiltration process, the existing NPRFs are installed on a large scale and mainly work with the reservoir process. Therefore, some limitations are expected in assessing both facilities using the same method as they differ in properties. To solve these problems, in this study, a new method for performance evaluation was proposed with focus on bio-retention LID facilities. EPA SWMM was used to reproduce the hydrologic and water quality phenomena in study area, and SWMM-LID module used to simulate TP interception performance by installing a bio-retention cell under various conditions through long-term simulations. Finally, an empirical formula for Load Capture Ratio (LCR) was derived based on storm water interception ratio in the same form as the existing method. Using the existing formula in estimating the LCR is likely to overestimate the performance of interception for non-point pollutants in the extremely low design capacity, and also underestimate it in the moderate and high design capacity.

• 한국구조물진단유지관리공학회 논문집
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• 제25권6호
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• pp.1-11
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• 2021

국내 대형 SOC 시설물의 노후화가 가속화됨에 따라 시설물 유지관리도 현재 상태 기준의 안전성 평가에서 미래 노후도 수준 예측을 기반으로 한 성능 중심의 예방적·선제적 유지 관리로 전환되고 있다. 특히, 교량의 경우 1·2종 교량은 많은 연구와 함께체계적으로 관리되고 있으나, 중소형 3종 교량은 사용 연한 동안 성능저하를 대변하는 이력 데이터 수집과 활용은 전무한 실정이다. 따라서 본 연구에서는 부재별 외관 손상에 대해 생애주기별 유지관리 이력을 3차원 교량 객체에 등록함으로써 손상 위치의 손상변화율 등을 직관적으로 확인 할 수 있고, API 기반 종합성능평가가 가능하도록 3D 교량모델 기반의 실증 DB시스템을 설계하여 개발하였다.

• 한국빅데이터학회지
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• 제5권1호
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• pp.97-108
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• 2020

국내 전력산업이 스마트 그리드화 되면서 이로 인해 발생하는 빅데이터를 활용하여 수요관리, 시설물관리, 대고객서비스 등을 위한 빅데이터 플랫폼들이 도입되고 있는 추세이다. 그러나 빅데이터 프로젝트의 속성상 실제로 빅데이터 플랫폼의 활용이 업무 프로세스 상에서 정착되기 위해서는 많은 시간과 업데이트가 필요하다. 따라서 기존에 알려져 있거나 이론적인 평가 방법으로는 초기 빅데이터 플랫폼의 성과를 평가하기는 적절하지 않다. 본 논문에서는 빅데이터의 규모, 다양성, 속도에 따른 정보의 완전성/충분성, 정보의 신뢰성/정확성, 정보의 적합성/관련성, 정보의 상세성/구체성, 정보의 비교가능성, 정보의 불편성, 정보의 적시성 등 특정 정보의 7 가지 품질 측면에서 전력산업에서 초기 빅데이터 플랫폼의 성과를 평가하는 방법론을 제시한다.

• 한국문헌정보학회지
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• 제47권4호
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• pp.49-78
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• 2013

본 연구의 목적은 전국 160개 병영도서관의 2011년 한 해 동안의 운영실적을 평가한 결과를 분석하여 병영도서관 운영을 진단하고 활성화 방안을 모색하기 위한 것이다. 평가 결과 전체 영역의 평균 도달률은 59.4%로 나타났다. 시설 영역(79.2%)과 교류협력 영역(71.0%)이 높은 도달률을 보인 반면, 계획 영역(28.3%)과 지원 영역(33.0%)은 상대적으로 낮은 도달률을 나타낸 것으로 조사되었다. 계획 영역에서의 낮은 도달률은 향후 병영도서관 활성화를 위해 추진되는 사업의 효율성을 제고하기 위해, 전략적인 계획 수립 및 집행에 대한 정책당국의 강력한 의지가 필요함을 보여주었다. 본 연구는 병영도서관 평가의 결과 분석 작업이 병영도서관 운영 개선방안을 도출하고 제시하는 것으로 이어져 향후 병영도서관 활성화 정책으로 연결되어야 함을 제안하였다.

• 대한전기학회논문지:전력기술부문A
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• 제54권4호
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• pp.177-184
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• 2005

This paper proposes a improved investment priority decision method of the facilities considering the reliability of distribution networks. The proposed method decides a investment order of the facilities combining, by fuzzy rules, the investment priority decision of KEPCO and the priority decision considering reliability evaluation indices. Where reliability evaluation indices are SAIFI(System Average Interruption Frequency Index) and SAIDI(System Average Interruption Duration Index), as referred to evaluation index for sustained interruption. The reliability analysis method of distribution networks applied in this paper utilizes analytic method, where the used reliability data is historical data of KEPCO. Particularly, we assumed that the failure rate increased as the equipment ages. To verify the performance of the proposed method, we applied it with the planned projects to reinforce the weak facility electrical facilities in KEPCO in 2004. The evaluation result showed that, under a limited budget, the reliability of the KEPCO in the Busan region using the proposed method can be enhanced than using the conventional KEPCO's method. Therefore, the results verify the proposed method can be efficiently used in the actual priorities method for investing the electrical facilities.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.65.2-65.2
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• 2010

Currently the variety of governmental business support and research for supplying solar energy have been actively progressed. As of now, however, There are no practical testing infrastructures of grid-connected photovoltaic system which test performance of solar power facility in domestic. Therefore, in KEPRI, there is in progress construction of practical testing ground of 500 kW class grid-connected PV System for developing the evaluation of the performance technology including the Module, PCS, and etc, that is the important instrument of the PV System, in Gochang area. It analyzed the site creation work for constructing the practical testing ground and new construction of control room and the unit standards, specifications and capacity of required equipment. For the system detailed design, configuration, instrument-specific parameters established, power generation predictions of Array Type and the components of testing ground are needed to build.

• 설비공학논문집
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• 제25권2호
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• pp.49-54
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• 2013

In field of apartment housing currently, insulation technology is the most effective way because it is common to improve the thermal performance, therefore, it is contributed to energy saving as several regional insulation standards and legal mandate method. In addition, by applying of building energy efficiency rating certification system, it has inspired voluntary energy conservation commitment for the building owner or facility manager by making a plan to evaluate and verify building energy performance. However, these circumstances are not enough to acquire a grade 2 of higher information. Therefore, in this study, we analyzed the impact of building energy efficiency rating and confirmed reduction ratio compared to the standard housing on the basis of recent our nation building law when we had changed the shape of windows and wall insulation performance and shapes of housing.