• 한국농공학회지
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• 제39권3호
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• pp.64-71
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• 1997

Floating aquatic plant system using water hyacinth was applied to examine feasibility as a wastewater treatment system for the industrial complex in rural area. The wastewater from the industrial complex does not likely contain toxic pollutants because the industries which generate wastewater with toxic compounds are not allowed to move in. Pilot plant was installed at Baeksuk Nongkong Danzi in Chunahn-City, Chunchungnam - Do , and field study was performed during summer and fall of 1996. Hydraulic loading rate was 0. $0.19m^3/m^2$.day. The effluent concentration of DO was higher than influent, and it implies that 0.6m depth reactor was reaerated enough to increase DO level. The influent concentration of BOD varied significantly from less than 30 to 120mg/${\ell}$ during the study period, however, effluent concentrations were generally lower than the water quality standard and removal efficiency was up to 85%. The influent concentration of COD also showed wide variation from less than 40 to 160mg/${\ell}$ and effluent concentration was higher than water quality standard when influent concentration was over l00mg/${\ell}$. The influent concentrations of T-N and T-P were lower than water quality standard and no further treatment was required, and these compounds were also removed in the system. Although some improvement and refinement are still required, overall* the floating aquatic plant system was proved to be feasible to apply to treat wastewater from industrial complex in rural area.

• 유기물자원화
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• 제20권2호
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• pp.53-65
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• 2012

본 연구에서는 국내 농공단지로부터 배출되는 폐수를 대상으로 폐수의 처리효율 특성을 전형적인 $A_{2}O$ 공정계열의 변법인, 배양조-혐기조-간헐포기조로 구성된 HBR-II 공정을 적용하여 이를 규명하고자 하였다. 또한 고도처리를 위한 상용화 플랜트 설계 시에 공정 조업 및 제어변수 값을 도출하고 HBR-II 공정의 고도처리 효율성을 경제적 측면에서 분석검토 하고자 하였다. 이를 위해 본 실험에서는, HBR-II 공정을 bench (또는 pilot) 규모의 실험 장치에 적용시켜 처리효율 실험을 수행하였으며, 1차 침전지 설계를 위한 회분식(batch type) 침전실험과 인(T-P)의 제거와 2차 침전지로부터의 난분해성 미세 부유고형물 입자의 배출농도 안정화를 위한 응집실험을 병행하여 이를 고도처리효율과 연계하여 최적의 침전 및 응집을 위한 공정조업 변수 값을 도출하고자 하였다. F/M비를 0.20~0.25 $BOD_5/Kg{\cdot}MLSS/Day$로 유지시켰으며, $BOD_5$ 98.4%, $COD_{Mn}$ 92.9%, SS 97.5%, T-N 91.3%, T-P 82.3% 의 높은 제거효율을 나타내었다. 본 연구를 통하여서 HBR-II 공정을 농공단지 폐수처리에 접목 할 경우 안정적인 수처리가 가능할 것으로 사료된다.

• 말소리와 음성과학
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• 제4권3호
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• pp.13-23
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• 2012

The sound /w/ has been traditionally regarded as an independent segment in Korean regardless of the phonological contexts in which it occurs. There have been, however, some questions regarding whether it is an independent phoneme in /CwV/ context (cf. Kang 2006). The present pilot study examined how Korean /w/ is realized in $/S^*wV/$ context by performing some perception tests. Our assumption was that if Korean /w/ is a part of the preceding complex consonant like $/C^w/$, it should be more or less uniformly articulated and perceived as such. If /w/ is an independent segment, it will be realized with speaker variability. Experiments I and II examined the identification rates as "labialized" of the spliced original stimuli of $/S^*-V/$ and $/S^{w*}-^wV/$, and the cross-spliced stimuli $/S^{w*}-V/$ and $/S^*-^wV/$. The results showed that round qualities of /w/ are perceived at significantly different temporal point with speaker and context variability. We therefore conclude that /w/ in $/S^*wV/$ context is an independent segment, not a part of the preceding segment. Full-scale examination of the production test in the future should be performed to verify the conclusion we suggested in this paper.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.122-128
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• 2000

Aerodynamic optimization of an automotive air-conditioning blower is a hard task because of the highly complex flow phenomena related to three-dimensional flow separations and the unsteady nature caused by the interaction between primary and secondary air flows throughout the fan. In this paper, an aerodynamic study on a forward-curved centrifugal fan has been carried out Firstly we obtained the fan performance curves versus flow rates showing its unstable nature in the surging operation range. Secondly aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage using a 5-hole pilot probe, at different operating conditions. Surface flow pattern near the cut-off area exhibits similar flow behavior above the best efficiency operating point, although the pressure level increases substantially with the Increase of flow rate. Vorticity in the casing passage flow occurs in all (low rates, downstream from the r-Z plane $\theta$=120 deg., where the position of its core changes with the circumferential location. Although complex, the general flow behavior were common, giving insight in its main aerodynamic features.

• Nuclear Engineering and Technology
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• 제50권4호
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• pp.532-541
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• 2018

Decision support systems are a key focus of research on developing control rooms to aid operators in making reliable decisions and reducing incidents caused by human errors. For this purpose, models of complex systems can be developed to diagnose causes or consequences for specific alarms. Models applied in safety systems of complex and safety-critical systems require rigorous and reliable model building and testing. Multilevel flow modeling is a qualitative and discrete method for diagnosing faults and has previously only been validated by subjective and qualitative means. To ensure reliability during operation, this work aims to synthesize a procedure to measure model performance according to diagnostic requirements. A simple procedure is proposed for validating and evaluating the concept of multilevel flow modeling. For this purpose, expert statements, dynamic process simulations, and pilot plant experiments are used for validation of simple multilevel flow modeling models of a hydrocyclone unit for oil removal from produced water.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.14-20
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• 2016

Remediation of crude oil contaminated soil is complicate and hard to apply traditional methods because of its persistency, durability, and high viscosity. Therefore, in this study, the efficiency of crude oil contaminated soil remediation was tested by developing a pilot-scale thermal desorption system using the indirect heating method with an exhaust gas treatment. Under optimal condition drawed by temperature and retention time, the remedial efficiency of crude oil contaminated soil and treatability of exhaust gas were analyzed. Total Petroleum Hydrocarbon (TPH) concentration of crude oil contaminated soil was decreased to 69.7 mg/kg on average and the remedial efficiency was measured at 99.60%. Through the exhaust gas, 86.0% of Volatile Organic Compounds (VOC) was degraded and 97.16% of complex malodor was reduced under the suggested optimum operation condition. This study provides important basic data to be useful in scaling up of the indirect thermal desorption system for the remediation of crude oil contaminated soil.

• Nutrition Research and Practice
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• 제11권5호
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• pp.402-411
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• 2017

BACKGROUND/OBJECTIVES: The role of a school's nutrition environment in explaining students' eating behaviors and weight status has not been examined in an Asian setting. The purpose of this study was to create a school nutrition environment index and to pilot test the index in elementary and middle schools in urban South Korea. SUBJECTS/METHODS: This study used a mixed-methods approach. Environment assessment tools were developed based on formative research, which comprised literature reviews, in-depth interviews, and focus group discussions. Key elements from the formative research were included in the assessment tool, which consisted of a structured survey questionnaire for school dietitians. Fifteen school dietitians from 7 elementary and 8 middle schools in Seoul completed the questionnaire. RESULTS: The formative research revealed four main sections that guided a summary index to assess a school's nutrition environment: resource availability, education and programs, dietitians' perceptions and characteristics, and school lunch menu. Based on the literature reviews and interviews, an index scoring system was developed. The total possible score from the combined four index sections was 40 points. From the 15 schools participating in the pilot survey, the mean school nutrition-environment index was 22.5 (standard deviation ${\pm}3.2$; range 17-28). The majority of the schools did not offer classroom-based nutrition education or nutrition counseling for students and parents. The popular modes of nutrition education were school websites, posters, and newsletters. CONCLUSIONS: This paper illustrates the process used to develop an instrument to assess a school's nutrition environment. Moreover, it presents the steps used to develop a scoring system for creation of a school nutrition environment index. As pilot testing indicated the total index score has some variation across schools, we suggest applying this instrument in future studies involving a larger number of schools. Future studies with larger samples will allow investigation of the validity and reliability of this newly developed tool.

• 한국전자파학회논문지
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• 제8권2호
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• pp.151-160
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• 1997

본 논문에서는 억압 파일롯트를 이용하여 복소 지연 프로파일을 추정, 코히어런트 Rake 다이버시티 합성을 실현하는 동시에 얻어진 지연 프로파일의 극대점을 찾아 칩동기를 행하는 DS /CDMA 방식의 성능평가를 이동위성 채널에서 해보았다. 이를 위해 shadowed Rician 페이딩 시뮬레이터를 구성하여 그 포락선 변동특성을 조사 하였고 이론적인 오율해석을 병행하였다. 그 결과로서 Heavy shadowing인 경우 그 포락선 변동은 지상이동 통신채널의 Rayleigh 페이딩의 완만한 주기적 변동에 비해 랜덤한 특성을 가져 심각한 데이터 오류를 가져 오리라 예상할 수 있다. 또한 이론적 오율해석으로부터 DS /CDMA방식은 협대역 QPSK 방식에 비해 Average shadowing하에서 약 10 dB이상 개선되었다. 그리고 억압 파일롯트 채널을 이용한 DS /CDMA 방식은 이동위성 채널에서 파일롯트 채널대 송선전력비, $\beta$=-8dB, 복소지연 프로파일수 $N_{profile}$=32 일때 오율성능변에서 최적점을 나타내며, 이값을 이용했을 때 Light shadowing하의 오율특성은 이상적인 QPSK 오율특성과 같은 결과를 얻을 수 있었다.

• 한국건설관리학회논문집
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• 제19권3호
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• pp.61-69
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• 2018

현재 국내에서는 지속적으로 제기되어 오던 건설 산업의 문제를 해결하고 건설산업의 선진화 및 발주방식의 다양화를 위하여 시공책임형 CM 발주방식을 도입하였다. 그러나 시공책임형 CM 규정이 신설된지 6년이 지났음에도 불구하고 용역형 CM에 비해 계약금액 실적이 현저히 떨어지고 있으며 공공부문 시공책임형 CM 프로젝트는 전무한 실정이다. 이에 따라 공공부문 시공책임형 CM 발주방식 정착을 위해 현재 한국토지주택공사 발주로 세 개의 시범사업이 진행되고 있으나 아직 시공책임형 CM에 관련한 세부법령이 미비하여 특례를 바탕으로 시행되고 있는 중이다. 따라서 본 연구에서는 현재 진행되고 있는 세 개의 시범사업에 참여중인 실무자를 대상으로, 이후 공공부문에서 시공책임형 CM 방식이 정상도입되어 본격적으로 활용될 경우 발생 가능한 리스크를 파악하고자 하였다. 본 연구의 결과를 바탕으로 이후 제도 개선 및 법령 제정에 기초자료로 활용할 수 있을 것이다.

• 한국환경농학회지
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• 제20권4호
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• pp.289-296
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• 2001

농공단지 폐수의 효과적인 처리를 위하여 스테인레스 전극판을 이용한 전기화학적 방법에 의한 pilot 실험 및 pilot 전기화학반응조를 생물공정의 전처리 과정으로 도입하여 이들 두 공정을 연계처리 실험을 하여 오염물질 제거효율을 조사하여, 이들 두 공정의 연계가능성을 조사한 결과는 다음과 같다. 전기화학방법에 의한 pilot 실험장치에서의 체류시간별 유출시간에 따른 COD 처리율은 체류시간 30분 및 60분에서 유출시간 8시간 이후부터 약 $78{\sim}81%$로 체류시간 15분으로 하였을 경우에 비해 그 처리율이 높았고, 탁도 처리율은 모든 조건에서 전기반응시간 초기부터 90%이상이었다. T-N 및 T-P 처리율은 체류시간 30 및 60분에서 유출 전 기간 동안 처리율이 각각 약 $71{\sim}74$ 및 $85{\sim}98%$로서 체류시간 15분에 비해 약간 높았다. 전기화학적 처리공정을 생물학적 처리공정의 전처리과정으로 도입한 실험과 단독 생물학적 처리공정의 실험을 동시에 실시한 결과에서의 SVI 및 MLSS의 농도변화는 유출 전 기간 동안 두 처리 공정 모두 각각 약 $82{\sim}112$와 $1,230{\sim}1,750$ mg/L로서 전반적으로 안정한 경향이었으며, SVI는 안정범위인 $50{\sim}150$을 충족시켰다. COD 처리율은 두 처리공정 모두 유출초기에 약 90%로 높았고 유출시간이 경과할수록 단독 활성슬러지 공정에서는 처리율이 미미하게 감소하였으나 전기화학반응조와 활성슬러지 공정을 연계한 처리공정에서는 미미하게 증가하여, 유출시간 72시간 후 COD 처리율은 각각 약 87 및 95%로서 전기화학반응조와 활성슬러지 공정을 연계한 처리공정에서 약 8% 증가하였다. 탁도 처리율은 두 처리공정 모두 유출 전 기간 동안 약 95%이상 높게 처리되었다. T-N 처리율은 유출 전 기간 동안 단독 활성슬러지 공정 및 전기화학반응조와 활성슬러지 공정을 연계한 처리공정에서 각각 약 $62{\sim}74$ 및 $72{\sim}86%$로서 연계한 공정에서 T-N 처리율이 10%이상 증가되었다. T-P 처리율은 전기반응조와 활성슬러지 공정을 연계한 처리공정에서 단독 활성슬러지 공정에 비해 유출 72시간후에는 각각 약 97 및 82%로서 전기화학반응조와 활성슬러지 공정을 연계한 처리공정이 약 15%이상 높았다.