• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.34-48
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• 2019

Naeseong Stream is a natural sand-bed river that flows through mountainous and cultivated area in northern part of Gyeongbuk province. It had maintained its inherent landscape characterized by white sandbars before 2010s. However, since then changes occurred, which include construction of Yeongju Dam and the extensive vegetation development around 2015. In this study, long-term monitoring was carried out on Naeseong Stream to analyze these changes objectively. This paper aims to provide a dataset of the investigation on channel morphology and vegetation for the period 2012-2018. Methods of investigation include drone/terrestrial photography, LiDAR aerial survey and on-site fieldwork. The main findings are as follows. Vegetation development in the channel of Naeseong Stream began around 1987. Before 2013 it occurred along the downstream reach and since then in the entire reach. Some of the sites where riverbed is covered with vegetation during 2014~2015 were rejuvenated to bare bars due to the floods afterwards, but woody vegetation was established in many sites. Bed changes occurred due to deposition of sediment on the vegetated surfaces. Though Naeseong Stream has maintained its substantial sand-bed characteristics, there has been a slight tendency in bed material coarsening. Riverbed degradation at the thalweg was observed in the surveyed cross sections. Considering all the results together with the hydrological characteristics mentioned in the precedent paper (I), it is thought that the change in vegetation and landscape along Naeseong Stream was mainly due to decrease of flow. The effect of Yeongju Dam on the change of the riverbed degradation was briefly discussed as well.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.399-399
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• 2016

현대 인류는 비약적인 경제성장으로 인하여 급격한 도시화와 산업화를 이루었다. 하지만 이러한 성장을 위해 수반되는 자원개발 및 생활환경조성으로 인한 토지개발이 진행되어 많은 양의 토양이 유실되고 있다. 토양유실을 관리하기 위해서는 모니터링을 통해 관리하는 방법과 모형을 통해 유실되는 토양의 양을 산정하여 관리방안을 제시하는 방법이 있다. 현재 전 세계적으로 사용되고 있는 범용토양유실량 산정공식(USLE)은 사용상의 편리성과 연간 토양유실량을 산정할 수 있는 이점이 있다. 뿐만 아니라 국내의 환경부에서는 USLE 공식을 적용한 '표토 침식 현황에 관한 고시'를 제정하여 유실되는 표토를 관리하고 있다. 하지만 USLE 공식을 구성하고 있는 인자 중 P factor는 경사도만을 고려하여 인자 값을 제시하고 있으며, 밭에 적용된 관리방법과 작물, 경운방법 등을 고려하지 않아 방법에 차이에 따른 발생되는 토양유실량에 차이가 발생하게 된다. 이러한 문제점을 고려하여 경작지의 경사도와 적용된 관리방안을 복합적으로 고려한 P factor 선정 체계가 필요한 시점이다. 따라서 본 연구에서는 실제 경작지 조사를 통해 경작지 별 관리방안과 경사도를 고려한 P factor를 제안하고자 한다. 관리방안과 경사도를 복합적으로 고려한 P factor를 제안하기 위해 선정된 유역은 강원도 양구군 해안면 유역과 자운리 유역, 안동시 임동면 반변천 상류 유역을 선정하여 위치하고 있는 밭에 대한 현장조사를 진행하였다. 조사항목은 경작지의 경사도, 재배작물, 관리방법, 경운방법 등을 조사하였으며, 이를 바탕으로 경사도와 관리방법을 복합적으로 고려한 P factor를 재산정 하였다. P factor를 재산정한 결과 대상 유역 내 밭에 적용된 관리방법과 경운방법, 재배작물의 차이로 인해 상이한 값이 산정되었다. 또한 기존 P factor와 재산정된 P factor를 사용하여 산정한 토양유실량의 차이가 약 17%정도 나타났다. 따라서 본 연구를 통해 재산정된 P factor는 토양유실에 직간접적으로 관여하는 조건들을 복합적으로 고려한 P factor로써 정확한 토양유실량을 산정하는데 기여할 것으로 판단되며, 본 연구를 바탕으로 전국단위 USLE P factor를 산정을 위한 추가적인 연구가 필요하다고 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2117-2121
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• 2009

우리나라는 도시화, 산업화로 하천의 환경적인 기능을 고려하지 못하고 심각한 수질오염을 유발하여 왔다. 특히 기술개발로 점오염원에 관리는 어느정도 효과를 보고있으나 정량화가 힘든 비점오염원 관리는 제대로 이루어지고 있지 않다. 우리나라의 강우시 수자원관리를 위한 기초자료로서 활용하기 위하여 본 연구에서는 강우시 수질특성을 파악하고자 하였다. 비점오염원의 특성상 유역별, 강우사상별 특징이 매우 다르므로 대표 유역에 대하여 장기적인 모니터링을 통하여 대표유역의 특성을 반영한 제한적인 누가유량-누가오염부하량의 관계식을 도출하여 좀더 정밀한 유역오염부하량을 산정하는 데 기여하고자 하였다. 연구 지점은 수도권 및 인근지역 주민의 식수원인 팔당호로 직 유입되고 정확한 유량자료 확보가 가능한 경안수위관측소 지점으로 선정하였다. 연구기간은 2007년 6월$^{\sim}$2008년 12월이었으며 이 기간에 나타난 강우 중 4개의 강우사상에 대하여 수질측정 및 실시간 수위관측을 실시하였다. 수위-유량관계곡선식으로 산정한 유량자료와 실측한 수질자료를 바탕으로 누가유량-누가오염부하량의 단순회귀식을 도출하였다. 수질항목은 수온, DO, pH, EC, SS, BOD, $COD_{Mn}$, $COD_{Cr}$, T-N, T-P 등이며 단, BOD는 2개의 강우사상에서만 측정되었다. 현장에서 휴대용미터를 이용하여 수온, DO, pH, EC를 측정하였고 나머지 항목은 한국건설 기술연구원내 환경정밀분석센타에 의뢰하여 분석하였다. 각 항목별 실측치를 이용한 누가유량-누가오염부하량 관계식을 도출한 결과 각 도출된 식의 상관계수 값은 전 항목에서 0.9 이상으로 1에 가깝게 나타나 높은 상관관계을 가지는 것으로 분석되었다. 항목별로 보면 BOD는 0.95, SS는 0.96, $COD_{Mn}$은 0.98, $COD_{Cr}$은 0.95, T-N은 0.97, T-P는 0.92의 값을 가졌다. 앞으로 장기적인 모니터링이 지속적으로 이루어져 다양한 강우사상별 자료가 축적된다면 좀더 정밀한 유량-부하량 관계식을 도출할 수 있을 것으로 판단되며 이는 수자원관리에 중요한 자료가 될 것으로 기대된다.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.109-119
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• 2019

Eutrophication has occurred due to the inflow of various water pollutants in many Korean reservoirs with low depth, and algal blooms of surface layer and low oxygenation of deep layer have repeated every year. There are several existing technologies to alleviate the stratification of reservoirs, but it is difficult to apply them in field sites due to the necessity of electric power and low economic efficiency. In this study, a non-powered water circulation system using natural energy of wind and water flow has been developed, and two test-beds constructed in the reservoirs with different conditions and examined its field applicability. Through computational fluid dynamics (CFD) simulation, it has been shown that the water circulation system could induce the downward flow to mitigate the stratification between surface and deep layers, and its influence radius could reach about 30 m. As a result of long-term monitoring of the test-beds, various water quality improvement effects have been observed such as moderation of DO fluctuation by water circulation, reduction of DO supersaturation and prevention of excessive pH rising. In order to improve the applicability of the water circulation system, it is considered necessary to review countermeasures against flood and depth conditions of each reservoir.

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.12-21
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• 2019

Specification is an important document for securing safe construction and improving quality as well as the contract document. Currently, the specifications used in modular buildings in Korea are only the construction specification, and most of the contents are used by borrowing the standard specifications of the building, so the contents of the modular buildings can not be reflected and it is contents are similar to the guideline book. The current status of domestic specification for modular buildings is affecting the quality of modular buildings. Therefore, we analyze activity through monitoring the modular process of modular buildings and analyze systematically relationship by applying IDEF modeling with analyzed activity. As result this paper proposes a structure of special specification specialized in modular building through generalization. The major classifications were divided into three stages : factory construction, transportation, and on-site installation. The specification structure was divided into 32 types of construction items from the floor slab assembly of the factory production to the joint finish of the on site installation in accordance with the opinion of experts.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4B
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• pp.405-411
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• 2008

The Nakdong River Estuary Barrage (NREB) was constructed in 1987 to prevent saltwater intrusion and to provide the sustainable water supply in the upstream channel. Sediment dredging has been conducted to eliminate deposited sediments in the approached upstream channel of the NREB. Fluvial changes and sedimentation problems have been continued due to urbanization and development in the watershed as well as construction of the NREB. However, the sufficient field monitoring and researches for sedimentation characteristics and bed changes have not been performed after construction of the NREB. Therefore, bed elevation changes and seasonal sediment concentration distribution were analyzed using the quasi-steady state model with historical field data in this study. The water surface elevation changes with and without sediment dredging operation were calculated using the developed quasi-steady state model and finally the sediment dredging effects were evaluated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.542-545
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• 2022

Recently, the Act on the Punishment of Severe Disasters has drawn attention to the construction environment. A common way to check the safety management of the construction site is for workers to check the site with their own eyes. However, this method is inevitably affected by the limitations of workers' abilities, resulting in fatigue and reduced work efficiency. For this reason, it cannot be an efficient method. Thus, we intend to help the working environment and construction site safety through this study, by proposing an efficient ICT safety management system that can supplement the above methods. In this paper explain the design of the access management system using RFID and the field information monitoring method through noise sensors and fine dust sensors. In addition, we propose a system that can prevent accidents between heavy equipment and people with a PIR sensor, and prevent safety accidents by grasping the slope of the building being worked through a gyro sensor.

• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.24-35
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• 2012

RFID-based logistics is increasingly adopted in various areas of the construction industry as a technology that can improve effectiveness and efficiency of construction logistics. However, the technology is not widely adopted yet compared to the potential of RFID applications in the construction industry that the existing research has shown. Since the validation and verification of the benefit from RFID applications were biased toward the productivity of managers, more wide aspect of validation and verification is necessary. Therefore, the objective of this paper is to show how much impact the RFID-based logistics management system can have on resource leveling and allocation that have a direct impact on a construction project as well as the managers' productivity improvement that was shown by the existing research. This paper also discusses issues arisen during the test process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.372-378
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• 2016

A mound was constructed to install a caisson and sofa blocks underwater. The mound riprap, which were of uniform grade, size, shape, and specific gravity, formed the foundation for the support superstructure. Also, rubble leveling works were performed before installing structures such as caissons. In this study, underwater construction equipment was developed with a remotely controlled operating system and underwater environment monitoring system for unmanned underwater rubble leveling work. The performance of the developed equipment was verified using on-land and underwater tests. In addition to the performance verification, the construction process and economic efficiency of the equipment should be checked before applying it to the real construction field for commercial purposes. In this paper, a construction process using the developed equipment was proposed and compared with the existing rubble leveling method. The results demonstrated that the new construction method has higher economic efficiency and safety than the existing construction method.

• 전자공학회논문지 IE
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• v.49 no.1
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• pp.12-17
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• 2012

Fast development of ubiquitous technology prompted the broadening of the related application area. Application of ubiquitous techniques and system into the construction sites may give us many benefits. There are always a lot of hazard situations in construction sites, and the falling is known to have the high accident rate. To prevent the falling, there has been a lot of efforts including safety education and use of safety gears. In this study, we designed, fabricated and tested a system that can monitor the worker's safety and location informations in real time by using the wireless technology of TOA and RSSI. We used ATmegal28 that is popular in the industrial equipments as MCU and NanoPan 5357 module from Nanotron and CC2500 chipset from TI for radio circuits. We also used 3-axis accelerometer and pressure MEMS sensors to obtain the environmental information, and therefore to aquire the informations of the worker's movement and altitude. We used Labview software from National Instrument to monitor and control the system. We developed the system to send the warning alarms to the server operator and the workers when the workers in the danger zone did not wear the safety hook.