• 대한환경공학회지
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• 제27권5호
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• pp.525-534
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• 2005

하상여과의 효율적인 적용에 대한 지침을 얻기 위해 이를 모사하는 칼럼실험을 수행하여 적용되는 수두차와 슬러지 케익의 발달에 따른 수질변화를 조사하였다. 하상여과에서 유기오염물을 제거하는데 가장 중요한 요소는 슬러지 케익의 발달임을 알 수 있었다. 본 연구의 조건에서 슬러지 케익의 발달에 따라 COD제거율은 17%에서 50%로 증가하였고, 이를 BCOD로 환산하면 22%에서 67%로 증가한 것이었다. BCOD가 활발히 제거되는 구간은 슬러지 케익층과 하상 약 40 cm 깊이까지였다. 수두차에 의한 유량이 클수록 칼럼입구에서 COD가 완만하게 제거되었으나 약 40 cm 이상에서는 COD 농도곡선이 유량에 따라 다르지 않고 모두 일정하게 수렴함을 알 수 있었다. 10일 동안의 슬러지 케익 발달 이후에는 70 cm 깊이에서 용존산소가 고갈되어 탈질이 가능하였으며, 케익이 더욱 발달함에 따라 용존산소의 고갈깊이가 $20{\sim}40\;cm$까지 단축되었다. 본 연구의 결과로부터 우리나라에 널리 분포되어 있는 3 m 깊이 정도의 하상에서 하상여과를 통해 유기오염물은 충분히 제거되지만 탈질에 의한 질소제거는 제한적임을 알 수 있었다.

• East Asian Economic Review
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• 제21권2호
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• pp.103-121
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• 2017

This paper experimentally studies the performance of negotiation considering individual and party, like a country, share of benefit over the best ones. It experiments two-stage bargaining games, internal and external negotiations. From the experimental results, this paper shows strong tendency to select fair allocation in the internal negotiations, but the tendency would be weaker with attractive outside option. In addition, the outside option may claim difference in individual benefit. From the regressions on individual performance in the negotiations, being a proposing party would matter to enhance the performance. However, relative individual performance within party fairness matters. Still attractive no-agreement options happen to break the tendency. As policy implication for trade negotiation, this paper warns that possible loss in individual benefit from not active participation to the external negotiations, no active role of proposer in case that players stick to internal allocations, and deviation of advantageous sector due to attractive outside options.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.387-392
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• 2006

There have been several problems in treating shipboard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on. It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.315-320
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• 2006

There have been several problems in treating shipboard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on. It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• Smart Structures and Systems
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• 제20권3호
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• pp.273-283
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• 2017

This paper presents and compares three feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity. These are a) control strategy based on direct output feedback (DOFB) b) control strategy based on linear quadratic regulator (LQR) to reduce structural vibrations and c) LQR control strategy with a weighting scheme based on structural-acoustic coupling coefficients. The first two strategies are indirect control strategies in which noise reduction is achieved through active vibration control (AVC), termed as AVC-DOFB and AVC-LQR respectively. The third direct strategy is based on active structural-acoustic control (ASAC). This strategy is an LQR based optimal control strategy in which the coupling between the various structural and the acoustic modes is used to design the controller. The strategy is termed as ASAC-LQR. A numerical model of a 3-D rectangular box cavity with a flexible plate (glued with piezoelectric patches) and with other five surfaces treated rigid is developed using finite element (FE) method. A single pair of collocated piezoelectric patches is used for sensing the vibrations and applying control forces on the structure. A comparison of frequency response function (FRF) of structural nodal acceleration, acoustic nodal pressure, and piezoelectric actuation voltage is carried out. It is found that the AVC-DOFB control strategy gives equal importance to all the modes. The AVC-LQR control strategy tries to consume the control effort to damp all the structural modes. It is seen that the ASAC-LQR control strategy utilizes the control effort more intelligently by adding higher damping to those structural modes that matter more for reducing the interior noise.

• 한국환경생태학회지
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• 제32권5호
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• pp.541-552
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• 2018

본 연구에서는 3~5세 유아교육기관 재원생 어머니들의 일상생활 속 미세먼지에 대한 인식을 알아보고 숲체험 프로그램 참가에 따른 숲과 미세먼지에 대한 인식의 차이를 분석하였다. 연구 대상은 숲체험 참가한 학모 61명과 숲체험에 참가하지 않은 학모 61명으로 총 122명에게 설문 조사를 하였다. 총 122명 중 82.8%의 학모들은 미세먼지에 대한 관심이 있고 자주 확인하는 빈도도 84.4%으로 높았지만 이에 대한 지식과 대처방안 및 줄이기 위한 적극적인 실천은 부족 하였다. 숲과 미세먼지에 대한 인식은 숲체험에 참여한 학모들에게서 숲의 역할 및 도심과 비교한 숲 환경의 차이에 대한 긍정적인 인식이 높았다. 따라서 어머니들이 먼저 숲을 적극적으로 체험 할 수 있는 기회가 확대 된다면 유 아동들의 숲체험이 활성화 될 뿐만 아니라 미세먼지를 비롯한 현재의 유해환경을 개선하는데도 기여 할 것이라고 생각한다.

• 농촌계획
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• 제19권2호
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• pp.193-202
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• 2013

This study aims at suggesting some measures to establish rural community development information system through ISP. A future model for rural community development information system was established by applying such 3-step ISP methodology as environment analysis, current status(AS-IS) analysis, future(To-Be) directions. As a result, with the vision of realizing comprehensive information service for rural development projects, rural development information system has established such goals as the assistance of project decision making through preparing rural development project data management system and acquiring evaluation efficiency, the preparation of spatial information utilization system, the utilization of objective GIS-based information through the increase of data management efficiency, the community activation and participatory rural development through rural spatial information portal service. In order to attain the goals, four strategical subject matters were derived. They are: 1) one-stop service subject matter for data management including pilot DB building for rural development projects, 2) rural information GIS service strengthening subject matter including DB building for rural development, O&M measures, 3) step-by-step DB building subject matter including the sharing of integrated information system for rural development, and 4) core value increase subject matter of spatial information data including the building of active service delivery system.

• 정보관리학회지
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• 제37권3호
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• pp.77-106
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• 2020

본 연구에서는 학제 간 연구가 가장 활발하고 응용가능성이 가장 높은 응집물질물리분야의 연구데이터를 체계적으로 관리하기 위한 개선방안을 제안하였다. 이를 위해 연구데이터 관리 도구인 Data Asset Framework (DAF)와 데이터 공유 및 재사용을 위한 FAIR원칙을 바탕으로 설문 내용을 구성하여 14명의 연구자를 대상으로 응집물질물리분야의 연구데이터 관리 현황을 수집하였다. 수집된 데이터는 설문에 응답한 연구자의 특성 및 기초정보, 데이터 보존 및 관리, 데이터 공유 및 접근에 관한 데이터로 구성되었다. 수집된 설문결과를 분석하여 응집물질물리분야의 연구데이터 특징과 데이터 수집과 생산, 데이터 보존과 관리, 데이터 공유 및 접근에 대한 9가지 문제점을 도출하였으며, 각 측면에서 도출된 문제점에 대한 개선방안을 제언하였다.

• 한국환경과학회지
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• 제29권2호
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• pp.177-189
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• 2020

We analyzed the recent characteristics of Particulate Matter (PM) including PM₁₀ (PM with diameter of less than 10 ㎛) and PM_2.5 (PM with diameter of less than 2.5 ㎛) observed in Busan metropolitan area, and compared them with those measured in Seoul metropolitan area. This analysis includes the monthly, seasonal, and annual variations and differences, in emissions and chemical compositions observed in both Busan and Seoul areas. Synoptic meteorological conditions were investigated at the time when high PM concentrations occurred in each of the two areas. The results showed clearly decreasing trends of annual mean concentrations with strong seasonal variations: lower in summer and higher in winter in both areas. In comparison with Seoul, the seasonal variation in Busan demonstrated relatively lower, but showed greater summer fluctuations than in Seoul metropolitan area. This is implying the importance of secondary generation of PM in summer via active photochemical reaction in Busan area. In high concentration days, Busan's chemical composition of sulfate was higher than that of nitrate in summer, whereas nitrate was higher than sulfate in Seoul. The ratios of NO₃^- to SO₄^2-(N/S ratio) showed lower in Busan approximately by a factor of 1/2(half of N/S ratio) in Busan compared with that in Seoul. Others such as synoptic characteristics and emission differences were also discussed in this study.

• Membrane and Water Treatment
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• 제9권3호
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• pp.163-172
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• 2018

This study investigated the effect of organic matter on the precipitation of struvite and calcium phosphate for phosphorus recovery from synthetic dairy wastewater. Batch precipitation experiments were performed to precipitate phosphorus from solutions containing $PO_4{^{3-}}$ and $NH_4{^+}$ by the addition of $Mg^{2+}$ and $Ca^{2+}$, separately, at varying pH, Mg/P and Ca/P molar ratios, and organic matter concentrations. Soluble total organic solids exhibited more inhibition to precipitation due to potential interaction with other dissolved ionic species involved in phosphorus precipitation. Xylan with low total acidity only exhibited significant inhibition at very high concentrations in synthetic wastewater (at up to 100 g/L). No significant inhibition was observed for Mg and Ca precipitation at relatively lower concentrations (at up to 1.2 g/L). MINTEQ simulations show that dissolved organic matter (DOM) as humic substances (HS) can cause significant inhibition even at relatively low concentrations of 0.165 g/L fulvic acid. However, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis suggested that xylan altered the crystal structure of both precipitates and had caused the formation of smaller sized struvite crystals with slightly rougher surfaces This could be due to xylan molecules adhering on the surface of the crystal potentially blocking active sites and limit further crystal growth. Smaller particle sizes will have negative practical impact because of poorer settleability.