• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.779-788
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• 2009

This study is the result of a field survey of four sewer networks selected from in domestic sanitary sewers. The main purpose of this study is to understand the characteristics of sediment in domestic sanitary sewers and to verify sewer design criteria using minimum Shear Stess for preventing sedimnet. This investigation was carried out at a total of 22 points in the four areas. The characteristics of the sanitary solids that were sampled for suspended solids and bedload matter showed a specific gravity of 1.09, a median particle size of 1.26mm, and 88.9% organic contents. On the other hand, deposited sediment was found at 6 points out of the 22 monitoring points. The analysis results of disposed sediment showed a specific gravity of 2.16, a median particle size of 1.31mm, and 15% organic contents. In flow velocity, the majority of deposited sites have under 0.6m/s. However, one-site which was in large-diameter collector sewers, has recorded over 0.6m/s. The analysis results of tractive force showed that the ability of tractive force has to be $1.5{\sim}2.0N/m^2$ to prevent sediment in domestic Sanitary sewers. In conclusion, to prevent sediment it is necessary to apply a design velocity criteria higher than 0.6m/s in the large diameter collector sewer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.421-431
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• 2023

Sewer deterioration models can offer important information on prediction of future condition of the asset to decision makers in their implementing sewer pipe networks management program. In this study, Markov chain model was used to estimate sewer deterioration trend based on the historical structural condition assessment data obtained by CCTV inspection. The data used in this study were limited to Hume pipe with diameter of 450 mm and 600 mm in three sub-catchment areas in city A, which were collected by CCTV inspection projects performed in 1998-1999 and 2010-2011. As a result, it was found that sewers in sub-catchment area EM have deteriorated faster than those in other two sub-catchments. Various main defects were to generate in 29% of 450 mm sewers and 38% of 600 mm in 35 years after the installation, while serious failure in 62% of 450 mm sewers and 74% of 600 mm in 100 years after the installation in sub-catchment area EM. In sub-catchment area SN, main defects were to generate in 26% of 450 mm sewers and 35% of 600 mm in 35 years after the installation, while in sub-catchment area HK main defects were to generate in 27% of 450 mm sewers and 37% of 600 mm in 35 years after the installation. Larger sewer pipes of 600 mm were found to deteriorate faster than smaller sewer pipes of 450 mm by about 12 years. Assuming that the percentage of main defects generation could be set as 40% to estimate the life expectancy of the sewers, it was estimated as 60 years in sub-catchment area SN, 42 years in sub-catchment area EM, 59 years in sub-catchment area HK for 450 mm sewer pipes, respectively. For 600 mm sewer pipes, on the other hand, it was estimated as 43 years, 34 years, 39 years in sub-catchment areas SN, EM, and HK, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.470-470
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• 2012

우수관거 시스템에서의 신뢰도 분석에 대한 기존 연구들은 시스템의 설계상에서의 각종 매개변수들에 대한 불확실성 분석에 기초하여 왔다. 그러나 본 연구에서는 동일한 설계빈도하에 설계된 우수관망이라 하더라도 관망의 노선 선정에 따라서 유출구에서의 첨두유출량 및 초과강우사상에 따른 침수 발생량이 달라질 수 있다는 점에 주목하였다. 그러므로 신뢰도 높은 우수관망을 설계하기 위해서는 이러한 침수 발생 확률을 줄일 수 있도록 하여야 하며, 이를 위해서는 관망 구성에 따라 달라지는 신뢰도를 하나의 정량화된 수치로 나타야 한다. 본 연구에서는 설계빈도를 초과하는 강우사상들에 대하여 해당 우수관망의 월류 발생 정도를 정량적으로 평가함으로써 상대적인 신뢰도를 하나의 지표로서 나타내고자 하였다. 이때 고려되는 것은 초과강우사상 발생 시 해당 관망에서의 월류 발생량 및 월류 발생 지점 개수이다. 또한 이때 고려 대상이 되는 월류량 및 월류 발생지점 수는 서로 다른 척도를 갖는 항목이므로 이에 대한 종합적인 고려를 위하여 본 연구에서는 다기준의사결정기법 중 하나인 DMM(Distance Measure Method)을 이용하였다. 본 연구에서 개발한 우수관망 신뢰도의 산정 절차는 다음과 같다. step 1) 초과빈도별 월류 발생량 및 월류 발생 지점 수 산정 step 2) 빈도별 월류발생량 비율( ) 및 월류발생지점 비율($N_i$) 산정 $$V_i$$ $$V_o/V/R$$ $$N_i=N_o/N_T/R$$ 여기서, $V_i$는 적용된 강우량당 유역의 전체 유출량 대비 월류발생량을 나타내며, $N_i$는 적용된 강우량당 해당 관망의 전체 지점 수 대비 월류 발생지점 수를 나타낸다. step 3) 중심점(central point)에 대하여 DMM을 이용한 치수안전성 산정 $$Reliability\;of\;Sewer\;Networks=1-\;{(1-N_i)^2+(1-V_i)^2\atop2}$$.

• Proceedings of the Korea Water Resources Association Conference
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• 1990.07a
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• pp.19-19
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• 1990

The paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrographs and inundation conditions within a small urban catchment. The model considers three typical flow conditions of urban drainage networks, whichn are overland flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with field data from a tested catchment having drainage area of 4.91 ha. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• Water for future
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• v.23 no.3
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• pp.329-340
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• 1990

The Paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrograhps and inundation conditions within a samll urban catchment. The model coniders three typical flow conditions of urban drainage networks, which are over-land flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with the field data from a tested catchment having drainage area of 0.049k$m^2$. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.9
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• pp.638-643
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• 2004

Middleware enables different networking devices and protocols to inter-operate in ubiquitous home network environments. The UPnP(Universal Plug and Play) middleware, which runs on a PC and is based on the IPv4 protocol, has attracted much interest in the field of home network research since it has versatility The UPnP, however, cannot be easily accessed via the public Internet since the UPnP devices that provide services and the Control Points that control the devices are configured with non-routable local private or Auto IP networks. The critical question is how to access UPnP network via the public Internet. The purpose of this paper is to deal with the non-routability problem in local private and Auto IP networks by improving the conventional Control Point used in UPnP middleware-based home networks. For this purpose, this paper proposes an improved Control Point for accessing and controlling the home network from remote sites via the public Internet, by adding a web server to the conventional Control Point. The improved Control Point is implemented in an embedded GNU/Linux system running on an ARM9 platform. Also this paper implements the security of the home network system based on the UPnP (Universal Plug and Play), adding VPN (Virtual Private Network) router that uses the IPsec to the home network system which is consisted of the ARM9 and the Embedded Linux.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.143-146
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• 2008

With unexpected torrential rainfall, flash flooding is occurring frequently and its impacts are tremendous. Thus proper natural disaster management plans are required. The disaster management system of the Bimodal tram utilizes the SWMM as a core engine to simulate runoff and urban sewer networks for flooding simulation. To develop the efficient Bimodal tram disaster management system, very detailed subcatchment boundaries and flow networks have to be developed in a GIS data format. Thus the objective of this study is to develop ArcView GIS based module (AV2SWMM) for easy preparation of model input for the tram disaster management system. With the AV2SWMM module, very detailed subcatchment boundaries and flow networks can be developed for accurate simulation of flash flooding at the study site, which were not/hardly possible with SWMM 5.0 interface. The AV2SWMM can be used in developing accurate model input for other regions where the Bimodal tram system is expected to be introduced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.451-457
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• 2018

We propose an automatic detection and classification system of sewer damage database based on artificial intelligence and deep learning. In order to optimize the performance, we implemented a robust system against various environmental variations such as illumination and shadow changes. In our proposed system, a crack detection and damage classification method using a deep learning based Convolutional Neural Network (CNN) is implemented. For optimal results, 9,941 CCTV images with $256{\times}256$ pixel resolution were used for machine learning on the damaged area based on the CNN model. As a result, the recognition rate of 98.76% was obtained. Total of 646 images of $720{\times}480$ pixel resolution were extracted from various sewage DB for performance evaluation. Proposed system presents the optimal recognition rate for the automatic detection and classification of damage in the sewer DB constructed in various environments.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.157-161
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• 2011

Although many researches have been carried out concerning the watershed division in natural areas, it has not been researched for the urban watershed division. If the boundary between two urban areas is indistinct because no natural distinction or no administrative division is between the areas, the boundary between the urban areas that have the different outlets (multi-outlet urban watershed) is determined by only designer of sewer system. The suggested urban watershed division model (UWDM) determines the watershed boundary to reduce simultaneously the peak outflows at the outlets of each watershed. Then, the UWDM determines the sewer network to reduce the peak outflow at outlet by determining the pipe connecting directions between the manholes that have the multi-possible pipe connecting directions. In the UWDM, because the modification of the sewer network changes the superposition effect of the runoff hydrographs in sewer pipes, the optimal sewer layout can reduce the peak outflow at outlet, as much as the superposition effects of the hydrographs are reduced. Therefore, the UWDM can optimize the watershed distinction in multi-outlet urban watershed by determining the connecting directions of the boundary-manholes using the genetic algorithm. The suggested model was applied to a multi-outlet urban watershed of 50.3ha, Seoul, Korea, and the watershed division of this model, the peak outflows at two outlets were decreased by approximately 15% for the design rainfall.

• Structural Monitoring and Maintenance
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• v.8 no.4
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• pp.361-378
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• 2021

While the pavement rating system is being utilized for periodic road condition assessment in the Eastern Region municipality of Saudi Arabia, the condition assessment is costly, time-consuming, and not comprehensive as only few parts of the road are randomly selected for the assessment. Thus, this study is aimed at developing a condition assessment model for a specific sample of a residential road network in Dammam City based on an individual road and a road network. The model was developed using the Analytical Hierarchy Process (AHP) according to the defect types and their levels of severity. The defects were arranged according to four categories: structure, construction, environmental, and miscellaneous, which was adopted from sewer condition coding systems. The developed model was validated by municipality experts and was adjudged to be acceptable and more economical compared to results from the Eastern region municipality (Saudi Arabia) model. The outcome of this paper can assist with the allocation of the government's budget for maintenance and capital programs across all Saudi municipalities through maintaining road infrastructure assets at the required level of services.