• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.87-95
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• 2010

The optimum volume of sediment settling pond is determined by the maximum rainfall and surface peak rate runoff from crop field. Based on analysis of measured rainfall and runoff data, it was found that rainfall intensity of 2 mm/min would result in peak rate runoff from the agricultural field of study area. Optimum pond volume under various slope scenarios were determined using the WEPP model calibrated with measured flow and sediment data for the study watershed. For the agricultural field with the slope of 7 % and area of $2,600\;m^2$ at the study area, at least $6.4\;m^3$ of sediment settling pond is needed as shown in this study. The results presented in this study could be used as a guide in designing appropriate volume of sediment settling pond at highland agricultural areas because both very detailed field measurement and calibrated WEPP model results are used in the analysis.

• Journal of Korea Water Resources Association
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• v.38 no.11
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• pp.927-935
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• 2005

Soil erosion by rainfall is important factor for basin management because it reduces reservoir capacity and breaks out the contamination of water caused by turbid water. Recently, soil erosion study with GIS is in progress but does not consider soil erosion source area. This study calculated soil erosion amount using GIS-based soil erosion model in Imha basin and examined soil erosion source area using SPOT 5 High-resolution satellite image and land cover map. As a result of analysis, dry field showed high-density soil erosion area and we could easily investigate source area using satellite image. Also we could examine the suitability of soil erosion area by applying field survey method in common areas such as dry field and orchard area those are difficult to confirm soil erosion source area using satellite image.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.1-7
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• 2012

Natural gas through pipeline is supplied to consumers after its pressure gets down compulsorily. The waste pressure energy of this process can be restored by use of turbo expander which can produce electricity. So, turbo expander conducts two functions - pressure reduction and power generation. The power amount is the enthalpy difference between the inlet and outlet states. The five main factors which affect economic profit are facility price, produced power amount, pre-heating amount, electricity cost, and fuel gas cost. Power generation depends mainly on flow amount because inlet and outlet states are fixed. A methodology to estimate economy in irregular flow pattern is proposed and using this way, a case study was carried out.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.1
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• pp.1-13
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• 2022

In Korea, attention is being paid to the use of renewable energy in the livestock industry, and Ground Source Heat Pump (GSHP), which is advantageous for temperature control, is considered as one of the ways to reduce the use of fossil fuels. But GSHP is expensive to install, which proper capacity calculation is required. GSHP capacity is related to its maximum energy load. Energy loads are affected by climate characteristics and time, so dynamic analysis is required. In this study, the optimal capacity of GSHP was calculated by calculating the heating and cooling load of pig farms using BES (Building Energy Simulation) and economic analysis was performed. After designing the inside of the pig house using TRNSYS, one of the commercial programs of the BES technique, the energy load was calculated based on meteorological data. Through the calculated energy load, three heating devices and GSHP used in pig farms were analyzed for economic feasibility. As a result, GSHP's total cost of ownership was the cheapest, but the installation cost was the highest. In order to reduce the initial cost of GSHP, the capacity of GSHP was divided, and a scenario was created in which some of it was used as an auxiliary heating device, and economic analysis was conducted. In this study, a method to calculate the proper capacity of GSHP through dynamic energy analysis was proposed, and it can be used as data necessary to expand the spread of GSHP.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.364-364
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• 2022

최근 기후변화에 따른 잦은 이상 가뭄으로 물 부족 현상이 심화되고 있어 물 안보가 중요한 사회적 이슈로 부각되고 있다. 물 부족에 대비하기 위해 수자원은 인류가 마음대로 사용할 수 있는 자유재가 아니라 보호·관리하여야 하는 대상으로, 보유한 미사용량을 회수·재배분하여 물 이용의 공정성을 강화 등 물 이용 제도의 전반에 대한 검토·개선이 필요한 실정이다. 하지만 일부 유역에서는 하천수 사용량이 정확하게 계측되지 않아 공정한 하천수 배분 등에 한계가 발생하고 있다. 본 연구에서는 충주댐 하류 유역에 위치한 자동유량측정소 원주시(남한강대교)와 여주시(남한강교) 상·하류 유량자료를 검토·분석하여 하천수 사용허가권에 등재된 하천수 이용량을 검토하고자 한다. 아울러 상·하류 자동유량관측소 내 지류 하천(섬강, 청미천)이 유입되고 있어, 추가 유입량을 고려한 물수지 분석을 위해 원주시(문막교)수위관측소, 여주시(원부교)수위관측소의 유량자료를 이용하였다. 상·하류 유량자료 검토 결과, 지류 유입량 + 하류 여주시(남한강교)) 유량이 상류 원주시(남한강대교) 유량보다 작은 상·하류 유량이 역전('19~'20, 평균 787,753m³/day)되는 흐름이 발생하였다. 구간 내 등재된 취수시설물(11개소) 허가량(39.66×10⁶m³) 보다 실재 사용량은 많을 것으로 추정되며 상·하류 역전 흐름에 직접적인 영향을 준 것으로 판단된다, 또한 현장 조사에서 허가대장에 미등재된 다수의 시설을 발견하였으며 이는 하천수의 효율적인 관리에 장애요인으로 작용된다. 하천수 사용은 복합허가사항으로 홍수통제소에서 사용허가부터 관리까지 실시하고 있는데 하천수 허가 신청량은 계획수요량 산정과 물수지 분석결과를 통하여 적정성 검토가 이루어지고 있다. 그러나 하천수 사용허가량 대비 실제 하천수 취수량이 얼마나 되는지 파악은 불가능한 실정이다. 결국 하천 유량을 관리하기 위해 강수량, 수위, 유량 등 많은 수문요소를 정확하게 측정하는 것도 필요하지만 이처럼 하천수 이용을 위해 취수되는 양을 정확하게 계측하지 않는다면 효율적인 하천수 관리는 어렵다. 하천수를 관리하고 효율적으로 이용하기 위해 하천수 이용에 대한 제도적인 보완이 필요해 보인다.

• Land and Housing Review
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• v.15 no.1
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• pp.135-146
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• 2024

This study predicts the means sharing ratio of the urban air transportation (UAM) when the VertiHub of the UAM in the southern western part is built at Songjeong Station in Gwanju. Based on Monte Carlo simulation of the utility function and means selection logit model for each means of transportation, our findings indicate an average mode share of 0.95%, with a variability range from 0.07% to 4.7%. Moreover, 95% of the simulation outcomes fall below a 2.02% mode share. Sensitivity analysis, conducted via Tornado Plot, highlights that the mode share is principally influenced by factors such as the unit fare, cost parameter, basic fare, and the time required for takeoff and landing. Notably, a negative correlation exists for unit fare, basic fare, and takeoff and landing time, suggesting the necessity of setting an appropriate level of fair to enhance UAM utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.215-217
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• 2014

A system architecture design relying only on the experience of its designer varies in quality in line with the designer's personal experience and knowledge ability. Likewise, a wrong estimation of hardware capacity ends up in waste of resources. In practice, a range of post-hoc monitoring tools are in operation, without providing any method for estimating and reflecting the performance at an early stage of architecture design. Provided capacity requirement is estimated in advance with simulation at the stage of design, the system capacity ends up in waste of resources. In practice, a range of post-hoc monitoring tools are in operation, without providing any method for estimating and reflecting the performance at an early stage of architecture design. Provided capacity requirement is estimated in advance with simulation at the stage of design, the system performance requirement can be met with a minimal cost while the waste of resources can be reduced to a great extent. In this context, the present study develops a pilot simulation model for hardware architecture design and then verifies its validity in an experiment. If the error rate falls within a permissible range in the experiment, the simulation model may be considered to reflect well the characteristics of real-life information system architecture.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.125-131
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• 2011

This research aims to investigate the cause of the occurrence of a weak road drainage section scientifically and specifically through a site survey for a poorly drained section occurring due to rainfalls during road operation. This paper deeply reviewed the existing research results and current situation data on the poorly drained sections accumulated in Korea Expressway Corporation in order to investigate the cause of the occurrence of a weak road drainage section, and deeply verified and analyzed the weak sections for the road surface drainage facilities and the other road drainage facilities by visiting the expressway controlled by the 6 local headquarters and 33 branches of Korea Expressway Corporation. As a result of site surveys for the weak road drainage sections, i) in a road surface section, occurrence of ponding in the road shoulder pavement due to slope changes, bad collection of water in the collecting well at a median strip, shortage of road shoulder dike height, and inferior construction, etc. was analyzed to be the main cause of the occurrence of poorly drained sections, and ii) in a road neighborhood section, the occurrence of pavement height difference in a main road and shoulder section due to inferior ditches on a slope and the bad drain age at the inlet and outlet of a culvert due to soil deposits, debris, etc. were analyzed to be the main cause of the occurrence of weak sections. Proposed as a plan to improve the poorly drainage section of road were i)calculation of capacity through material changes at the ditch, enhancement of vertical sections and hydraulic analysis in terms of construction and other aspects, ii)derivation of a combined slope considering a slope and a vertical linearity and maintenance of proper distance between drainage structures in a vertical concave section in terms of geometrical structure, and iii)calculation of the drainage facility installation interval using a minutely rainfall intensity formula and a non-uniform flow analysis technique in terms of hydraulics and hydrologics and prompt removal of rainfalls from the road surface according to a linear drainage method.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.75-84
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• 2023

Many developing countries face challenges in estimating long-term discharge due to the lack of hydrological data for water supply planning, making it difficult to establish a rational water supply plan for decision-making on water distribution. The study area, the Bandung region in Indonesia, is experiencing rapid urbanization and population concentration, leading to a severe shortage of freshwater. The absence of water reservoir prediction methods has resulted in a water supply rate of approximately 20%. In this study, we aimed to propose an approach for predicting water reservoirs in developing countries by analyzing water safety and potential water supply using the MODSIM (Modified SIMYLD) network model. To assess the suitability of the MODSIM model, we applied the unit hydrograph method to calculate long-term discharge based on 19 years of discharge data (2002-2020) from the Pataruman observation station. The analysis confirmed alignment with the existing monthly optimal operation curve. The analysis of power plant capacity revealed a difference of approximately 0.30% to 0.50%, and the water intake safety at the Pataruman point showed 1.64% for Q95% flow and 0.47% for Q355 flow higher. Operational efficiency, compared to the existing reservoir optimal operation curve, was measured at around 1%, confirming the potential of using the MODSIM network model for water supply evaluation and the need for water supply facilities.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.377-377
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• 2017

다목적댐은 비어있는 저수지 용량을 활용, 상류에서 유입되는 홍수를 저류하여 하류의 피해를 경감시키고, 저류된 저수량을 활용하여 갈수시 생 공 유지용수 등을 목적에 맞게 하류로의 공급에 주요 목적이 있다. 이를 위해 댐 계획에는 상류에서 유입되는 목표 빈도 계획홍수량을 산정하고, 이에 따른 여수로의 계획방류량 등이 포함된 홍수 조절 방안이 수립된다. 다목적댐은 그 중요도 때문에 많은 사회적 재화(財貨)가 투입되어 하천에서 가장 높은 빈도인 200년 빈도 홍수량에 대비하도록 설계되어 있다. 그러나 대부분의 댐 하류 하천에서는 긴 연장에 따른 투자비용 등의 한계로 상류 댐에 미치지 못하는 100년 빈도 이하로 설정되어있다. 이런 상 하류의 홍수계획간 괴리로 댐의 계획 방류량 수준의 홍수 조절시에는 하류 하천에 재난상황으로 발생할 우려가 있다. 기상예보의 고도화로 단기 예보의 정밀도가 높아져 단기간 댐 운영에는 효과적으로 활용되고 있다. 하지만 5일 이후를 예보하는 중 장기예보는 아직까지도 불확실성이 높은 실정이다. 여기에 기후변화 등 기상의 불확실성을 고려하여 홍수기 초 장마와 태풍 등의 영향에 대비하기 위해 무작정 댐을 저(低)수위로 운영하면 이후 여름 가뭄에 취약해 지고, 반대로 저수량 확보의 고(高)수위 운영을 할 경우 연이은 태풍 등 홍수상황에 취약해 지게 된다. 최근 '14~'15년도 낙동강 수계에 여름가뭄으로 안동 임하댐이 가뭄단계에 돌입하는 등 홍수기초 적정 저수량의 확보는 안정적 수자원시설 운영에 중요성이 커지고 있다. 본 연구에서는 이러한 불확실한 기상상황에 대비하고 댐의 이치수 목적 달성을 위해, 홍수기초 가능한 저수량을 확보하되 계획홍수량이 들어와도 하류피해는 경감시킬 수 있는 저수지 수위를 찾고자하였다. 이를 위해 낙동강 수계 9개 다목적댐(안동, 임하, 성덕, 보현산, 군위, 김천부항, 합천, 남강, 밀양댐)을 대상으로 댐 설계 및 직하류 하천 상황을 고려한 "홍수기초 댐 저수량 확보 수위 검토"를 실시하였다. 댐 직하류 하천의 홍수대비 상황 및 홍수조절시 제약사항 등을 조사해 주요지점(Critical Point)을 선정하고 그 지점의 홍수량을 파악한다. 이어서 저류함수 모형을 활용하여 댐별 저수지 모의 운영을 실시하였다. 대상 댐 저수지에 계획홍수량을 유입시키고 수위를 점차 조정하면서 하류 지점의 홍수량 내의 규모로 방류를 하는 저수지 모의 운영을 실시하였다. 이때 저수지의 계획홍수위를 초과하지 않는 등 안정적 홍수조절이 가능한 특정 수위를 찾아 하류 하천 환경을 고려한 댐 운영 수위로 선정하였다. 최근 홍수기총에는 강수량이 계속 줄어들고 홍수기 이후 더 많은 강수가 내리는 등 기후변화로 댐 운영은 날로 어려워지고 있다. 본 연구의 분석 결과는 홍수기초 가뭄 및 장마 또는 태풍 등에 대비하여 댐 운영의 이 치수 두 가지 목적을 달성하는데 참고가 될 수 있을 것이다.