Soyeon Lim

Sehyeong Kim

Jaehyun Kim

Jeongseok Oh

Hyewoon Jang

The Advanced Water Resources Engineering Lab at Korea University focuses on water resources engineering research. The lab is seeking self-motivated undergraduate students interested in academic careers.

고려대학교 첨단 수자원 공학 연구실은 수자원 공학 연구에 중점을 두고, 학계 진출에 관심 있는 학부 연구생을 모집한다.

Modular interdependency analysis for water distribution systems

Three-dimensional convolutional neural network for leak detection and localization in smart water distribution systems

Exploration of Deep Learning Leak Detection Model across Multiple Smart Water Distribution Systems: Detectable Leak Sizes with AMI Meters

Identifying the Drought Impact Factors and Developing Drought Scenarios using the DSD Model

Ensemble CNN Model for Effective Pipe Burst Detection in Water Distribution Systems

Policy Evaluation of Economic – Environmental Tradeoffs in Regulating Industrial Water Use: An Agent-Based Model

Tree-based ensemble machine learning model for nitrate reduction by zero-valent iron

Biochar-based persulfate activation: Rate constant prediction, key variables identification, and system optimization

Robustness-based design of water distribution systems

Water distribution system burst detection using a nonlinear Kalman filter

Linear model for estimating water distribution reliability

State estimation network design for water distribution systems

Using Mechanical Reliability in Multi-objective Optimal Meter Placement for Pipe Burst Detection

Water Distribution System Design to Minimize Costs and Maximize Topological and Hydraulic Reliability

Accuracy of First-Order and Second-Moment approximation for uncertainty analysis of water distribution systems

Hybrid Statistical Process Control Method for Water Distribution Pipe Burst Detection

Accounting for Phasing of Isolation Valve Installation in Water Distribution Networks

Comparison of imputation methods for end-user demands in water distribution systems

Multiperiod Optimization Framework for Urban Drainage System Planning: Scenario-Based Approach

Seismic hazard assessment model for urban water supply networks

Enhanced artificial neural networks estimating water quality constraints for the optimal water distribution systems design

Seismic-reliability-based multiobjective design of water distribution system: sensitivity analysis

Investigating the impact of proactive pump operation and capacity expansion on urban drainage system resilience

Improving the quality of Pareto optimal solutions in water distribution network design

Robust urban drainage system: Development of a novel multiscenario-based design approach

Optimal layout and pipe sizing of urban drainage networks to improve robustness and rapidity

Optimal node grouping for water distribution system demand estimation

Multiobjective automatic parameter calibration of a hydrological model

Robust meter network for water distribution pipe burst detection

Robustness and Water Distribution System: State-of-the-Art Review

Optimization Difficulty Indicator and Testing Framework for Water Distribution Network Complexity

Emerging issues and methodologies for resilient and robust water distribution systems

Development of Failure Cause-Impact-Duration (CID) Plots for Water Supply and Distribution System Management

Development of a Fuzzy-Function-based Performance Indicator for Water Distribution System’s Emergency Condition

Development of a Multiple Linear Regression Model for Meteorological Drought Index Estimation Based on Landsat Satellite Imagery

Seismic-reliability-based optimal layout of a water distribution network

Flood reduction in urban drainage systems: cooperative operation of centralized and decentralized reservoirs

Improving Water Distribution Robustness through Optimal Valve Installation

Generation of Benchmark Problems for Optimal Design of Water Distribution Systems

Future Water: A Multi-University International Web Seminar

Comparison of the robustness-based optimal design of water distribution systems in three different formulations

Improving the rapidity of responses to pipe burst in water distribution systems: A comparison of Statistical Process Control methods

Robustness-based optimal pump design and scheduling for water distribution systems

Optimal meter placement for pipe burst detection in water distribution systems

Real-time pump scheduling for water transmission systems: Case study

Development of a hybrid harmony search algorithm for water distribution system design

Relationship between downstream hydraulic geometry and suspended sediment concentration characteristics

Development of Cross-domain Artificial Neural Network to Predict High-temporal Resolution Pressure Data

Shortest-path-based Design Model for Hydraulically Efficient Water Distribution Network: Preparing for Extreme Changes in Water Availability

Development of a Multiobjective Automatic Parameter-Calibration Framework for Urban Drainage Systems

Development of a Water Quality Event Detection and Diagnosis Framework in Drinking Water Distribution Systems with Structured and Unstructured Data Integration

A Review of Ground Camera-based Computer Vision Techniques for Flood Management

Advancements in Multimodal Differential Evolution: A Comprehensive Review and Future Perspectives

Comparison of Machine- and Deep-Learning Methods for Mapping Sea Farms Using High-resolution Satellite Image

Development of a multiscenario planning approach for urban drainage systems

Performance comparison of metaheuristic algorithms using a modified Gaussian fitness landscape generator

Application of life cycle energy an alysis for designing a water distribution network

Strategy to Enhance Emergency Interconnected Operation of Water Distribution System

Wave-induced structural response analysis of the supporting frames for multiconnected offshore floating photovoltaic units installed in the inner harbor

Estimation of reaction forces at the seabed anchor of the submerged floating tunnel using structural pattern recognition

Geometric and structural assessment and reverse engineering of a steel-framed building using 3D laser scanning

Dilemma of a small dam with large basin area under climate change condition

Evaluation of plastic deformation for steel coupons using thermography

Improving erosion resistance of sandy soils using zein biopolymer

Mooring tension estimation for multi-connected floating photovoltaic arrays via LSTM networks

Improving the rapidity of responses to pipe burst in water distribution systems: A comparison of statistical process control methods

Flood reduction in urban drainage systems: Cooperative operation of centralized and decentralized reservoirs

Linear model for estimating water distribution system reliability

Water distribution system design to minimize costs and maximize topological and hydraulic reliability

Enhanced Artificial Neural Networks Estimating Water Quality Constraints for the Optimal Water Distribution Systems Design

Development of a multiple linear regression model for meteorological drought index estimation based on landsat satellite imagery

Improvement and application of pump station operating system and economic analysis of the application

Improving water distribution systems robustness through optimal valve installation

Hybrid statistical process control method for water distribution pipe burst detection

Optimal design of water distribution systems considering uncertainties in demands and roughness coefficients

Detecting pipe bursts using Heuristic and CUSUM methods

Joong Hoon KIM

Doosun Kang

Do Guen Yoo

Donghwi Jung

A water distribution system burst from a sudden pipe failure results in water loss and disruption of customer service. Artificial neural networks, state estimation, and statistical process control (SPC) have been applied to detect bursts. However, system operational condition changes such as the set of operating pumps and valve closures greatly complicates the detection problem. Thus, to date applications have been limited to networks that are supplied by gravity or under consistent operation conditions. This study seeks to overcome these limitations using a nonlinear Kalman filter (NKF) method to identify system condition, estimate system state, and detect bursts.

Robustness is generally defined as an ability of a system to maintain its function under a defined set of disturbances. To introduce robustness to the water distribution systems (WDSs) design, chance constrained, or so-called reliability-based models have been formulated. Under variations in system parameters, such as nodal demands and pipe roughness, system reliability is generally measured as the probability that the stochastic nodal pressures will be higher than an allowable minimum pressure limit. However, chance constraints may not be the best formulation to improve system robustness because it focuses on the likelihood of failure under a specified set of conditions rather than developing a solution that consistently provides adequate service. In addition, the reliability-based design requires defining the demand condition, its probability distribution and its statistics, which are not straight forward in practice …

A pipe burst is a major water distribution system failure. Water escapes the network through the break increasing the total flow entering the network. These higher flows, in turn, increase the head losses in pipes and result in lower water pressures at customer taps. This study focuses on burst detection by seeking to identify anomalies in net system demand, pipe flow rates, and nodal pressure heads. Three univariate statistical process control (SPC) methods (the Western Electric Company rules, the cumulative sum (CUSUM) method, and the exponentially weighted moving average [EWMA]) and three multivariate SPC methods (Hotelling T 2 method and multivariate versions of CUSUM and EWMA) are compared with respect to their detection effectiveness and efficiency. First, the three univariate methods are tested using real system burst detection and then the six SPC methods are compared using synthetic data …

A new seismic reliability evaluation model is proposed that quantifies the impact of earthquakes on hydraulic behavior of water supply networks. Probabilistic seismic events are produced in the target areas, and the depth of earthquake failure is evaluated by seismic reliability indicators. The developed model was applied to several case studies and used for an intensive examination on how a water supply system hydraulically responds to a seismic event and what system characteristics influence the system’s performance in the event of an earthquake. First, the system reliability of a real network in South Korea when subjected to earthquakes of various magnitudes and locations was quantified. Next, the reliabilities of full and simplified network models were evaluated to investigate how system layouts affect the reliability evaluation. Finally, networks with different configurations, pipe sizes, and system densities were …

In this study, a hydrodynamics-based structural response analysis procedure of supporting frames for multiconnected offshore floating photovoltaics (FPVs) is suggested. Based on the suggested simulation methodology, the dynamic behavioral characteristics of the system were investigated. First, rational mooring types for FPVs installed in the inner harbor were studied based on the analysis results. Subsequently, extensive parametric studies have been conducted to determine a rational design strategy for dynamic response mitigation. In this study, the effects of the initial configuration and axial stiffness of taut mooring lines, arrangement angles of FPV systems, and floater dimensions on the static and dynamic responses of supporting frames under irregular waves in the inner harbor were studied. The corner module in the multiconnected system showed critical responses among others, the investigation of which is …

Pipe bursts in water distribution systems (WDS) must be rapidly detected to minimize the loss of system functionality and recovery time. Pipe burst is the most common failure in WDS. It results in water loss out of the system, increased head losses, and low pressure at the customers' taps. Therefore, effective and efficient detection of pipe bursts can improve system resilience. To this end, this study proposes an optimal meter placement model to identify meter locations that maximize detection effectiveness for a given number of meters and type of meter. The linear programming model is demonstrated on a modified Austin EPANET hydraulic network. Receiver operating characteristic (ROC) curves for alternative pressure and flow meters are applied to investigate the relationship between the level of available information and pipe burst detection effectiveness. The optimal sensor locations were distinctly different …

Failure of drainage systems leads to urban flooding; therefore, structural measures such as the installation of additional drainage facilities, including pump stations and detention reservoirs, have been adopted in the past to prevent and mitigate urban flooding. These measures, however, are costly and time consuming. To maximize flood mitigation efficiency, it is essential to also implement non-structural measures such as effective operation of drainage facilities. In this study, we propose a new cooperative operation scheme for urban drainage systems that involves linking centralized reservoir (CR) and decentralized reservoir (DR) operations by sharing water level information at monitoring nodes. Additionally, we develop a resilience index to assess the system's ability to mitigate, restore, and recover from inundation (i.e., failure). Most results show that flood reduction and resilience in cooperative operations are better than the current operation. However, the results of CR operation for 2010 are worse than the current operation at high monitoring node levels (1.4 m–1.5 m), and the results of DR operation for 2011 are worse than the current operation at low monitoring node levels (0.8 m–0.9 m). All results related to flood reduction and resilience in cooperative operation are superior to the current operation.

The individual and combined effects of structural and nonstructural measures on urban drainage system resilience were investigated in this study. The resilience of an urban drainage system is the system’s ability to recover from flooding or inundation damage. A novel pump operating method is proposed in this paper as a nonstructural measure, while expansion of the discharge pump capacity is considered to be a structural measure. The proposed method is demonstrated by application to the Daerim sewer network in Seoul, Korea, which has a discharge pump located in the detention reservoir at the center of the study network. The results show that less flooding is predicted with the new operating method than with the current operating method. Additionally, the new operating method, in conjunction with a pump capacity reflecting the inflow into the detention reservoir, yields stable results in most operating …

The water distribution system (WDS) reliability is the ability of a network to provide the required quantity of water to customers under uncertain system conditions. In this study, eight surrogate measures of WDS reliability were investigated: Two hydraulic reliability measures, two robustness measures, single failure reliability (SFRel) with three valve installation levels, and seismic reliability (SeisRel). The eight reliability measures were calculated for 16 study networks of various sizes (i.e., in terms of the number of nodes and links), numbers of sources, layouts, demand distributions, and topographies. The network characteristics (e.g., structural redundancy and overall pipe sizes) were quantified by using system characteristic indicators (SCI), and their correlations with the eight suggested reliability measures were analyzed. The following SCIs were considered: The average node degree, meshedness coefficient, total …

Many surrogate measures for water distribution system (WDS) reliability have been introduced in the last three decades. This study investigated the differences between designs based on topological and hydraulic reliabilities. The former considers network structural redundancy and connectivity, whereas the latter considers system performance under uncertain future conditions. Two topological reliabilities are proposed based on the network theory: the average node degree ratio ( ) and meshedness coefficient ratio ( ). The capacity reliability and robustness are classified as hydraulic reliability. The Pareto optimal pipe sizes and configuration were found for a real medium-size grid-type network to minimize the total cost and maximize , , capacity reliability, and robustness individually. The nondominated sorting genetic algorithm II was used for the optimization, and the uncertainty of the nodal …

This study proposes variable balancing approaches for the exploration (diversification) and exploitation (intensification) of the non-dominated sorting genetic algorithm-II (NSGA-II) with simulated binary crossover (SBX) and polynomial mutation (PM) in the multiobjective automatic parameter calibration of a lumped hydrological model, the HYMOD model. Two objectives—minimizing the percent bias and minimizing three peak flow differences—are considered in the calibration of the six parameters of the model. The proposed balancing approaches, which migrate the focus between exploration and exploitation over generations by varying the crossover and mutation distribution indices of SBX and PM, respectively, are compared with traditional static balancing approaches (the two dices value is fixed during optimization) in a benchmark hydrological calibration problem for the Leaf River (1950 km 2 ) near Collins, Mississippi. Three performance metrics—solution quality, spacing, and convergence—are used to quantify and compare the quality of the Pareto solutions obtained by the two different balancing approaches. The variable balancing approaches that migrate the focus of exploration and exploitation differently for SBX and PM outperformed other methods.

Optimal water distribution system (WDS) design including the layout and pipe sizes is invariably complex, even when hydraulic constraints alone are considered. The addition of water quality (WQ) constraints adds to the computational demands. Using conventional WQ models to evaluate the feasibility of the many networks that must be analyzed can extend the optimization process beyond acceptable limits. Artificial neural networks (ANNs) can approximate disinfectant concentrations in a fraction of the time required by deterministic WQ models, and thus have been used for WDS pipe optimization as fast surrogates of these models. This study seeks to improve the performance of ANNs applied to the optimal design of WDSs by comparing their outcomes on the basis of ANN architecture and data used for ANN training, two factors that affect their speed and accuracy. ANNs were trained to forecast the disinfectant …

This study develops a real-time near-optimal pump scheduling model for water transmission networks. The model aims to minimize energy cost by means of optimal pump operation while meeting system demands and satisfying operational constraints. The real-time control is realized using Supervisory Control and Data Acquisition (SCADA) system, by which system monitoring data is collected and the optimal control decisions are sent to the pumping stations for implementation. The model is composed of three simulation modules, such as demand forecasting, hydraulic simulation, and optimization. Decision variables include pump on/off (binary code of 0/1) schedules for fixed-rate pumps for each time-step over pre-defined operation time horizon. Various operational constraints are embedded in the model reflecting real operational practices. The proposed optimization model is demonstrated using a real, medium …

Climate polarization due to global warming has increased the intensity of drought in some regions, and the need for drought estimation studies to help minimize damage is increasing. In this study, we constructed remote sensing and climate data for Boryeong, Chungcheongnam-do, Korea, and developed a model for drought index estimation by classifying data characteristics and applying multiple linear regression analysis. The drought indices estimated in this study include four types of standardized precipitation indices (SPI1, SPI3, SPI6, and SPI9) used as meteorological drought indices and calculated through cumulative precipitation. We then applied statistical analysis to the developed model and assessed its ability as a drought index estimation tool using remote sensing data. Our results showed that its adj.R 2 value, achieved using cumulative precipitation for one month, was very low (approximately 0.003), while for the SPI3, SPI6, and SPI9 models, the adj.R 2 values were significantly higher than the other models at 0.67, 0.64, and 0.56, respectively, when the same data were used.

In low-lying districts of urban areas, pump stations were built to protect flooding by the heavy rain. Particularly, the automatic pump operation system was installed for efficiency in the pump stations of Seoul. However, the effective pump operation is difficult under existing operating system because the system only performs operation by reservoir depth. This study would like to improve the real time operating system suggested by Jun et al.(2007) and to apply the system Gasan 1 pump station in Seoul. For various design rainfall events, maximum water levels simulated by the suggested system were 10~ 70cm lower than results by the existing system. And overflow volume at upstream manholes were 50% reduced. We converted the flood control effects by establishment of the suggested system to economic indicators. To obtain the same effect, approximately 4.9 billion won needs to expand pump capacities or 3.2~ 6.9 hundreds million won needs to construct storm water detention on upstream area. The suggested system could improve the flood control stability by efficient operation of the existing pump station.

This study examines the impact of advanced metering infrastructure (AMI) end-user demand metering failure on water distribution system (WDS) operation and management. To address this issue, our first step is to develop a burst detection algorithm that compares total end-user demands with system inflow rates. Western Electric Company (WEC) rules are applied to test for anomalies in the time series of normalized differences between supply and withdrawal. Then, hydraulic model prediction and burst detection performance are evaluated for fully reporting and missing AMI demand conditions using synthetically generated end-user demands for a network in Tucson, Arizona. Three imputation methods [zero, historical mean (HM), and distribution sampling (DS) method] are applied to replace missing AMI data and are compared for a range of missing data percentages. Based on the numerical experimental results …

This study proposes a framework for improving the robustness of water distribution systems using the optimal valve installation approach with regard to system reinforcement. To improve the robustness in valve design, this study introduces critical segment selection technique and optimal valve location determination within the concept of segment. Using the segment finding algorithm, the segment and the unintentional isolation can be identified. To select the critical segment, a multicriteria decision technique is applied by considering the hydraulic, social and economic effect. Finally, the optimal valve locations and the number of additional valves is determined by pipe failure analysis through the trade-off relationship with the number of additional valves and the maximum damage under pipe failure situations. To verify the proposed technique, the real-world water distribution systems are applied and compared with the original design.

Statistical process control (SPC) identifies any nonrandom patterns in the system output variables of a water distribution system (WDS) by comparing them to their normal historic mean and variance. While each SPC method has different performance characteristics, there has been little effort expended to develop a hybrid method that combines the different characteristics. This paper proposes a hybrid SPC method that combines a modified Western Electric Company (WECO) method and the cumulative sum (CUSUM) method. First, the original WECO method is modified to incorporate a user-defined parameter that manipulates the tolerance for warning and control limits to fit the specific network of interest. Then, the best parameter set is identified for each of the two individual methods so that coupling them should not increase false alarms. The detection effectiveness and efficiency of the WECO, CUSUM, and …

The optimal design of water distribution system has been usually performed with fixed hydraulic variables and single objective. However, a realistic water distribution system should take inherent uncertainties of data into consideration. This study suggests a method to minimize the system cost and maximize the robustness of network based on uncertainties in nodal demands and pipe roughness coefficients. Multi-Objective Genetic Algorithm (MOGA) implements two separate optimization models for the least cost and the best robustness design as the initial population. The model considers the uncertainties in roughness coefficient and water demand by using Latin Hypercube sampling techniquewith the assumption of beta probability density function. Several beta probability density functions with wide range of data are evaluated in the procedure. The proposed approach is tested in case study of the New York …

Pipe bursts in a drinking water distribution system lead to water losses, interruption of supply, and damage to streets and houses due to the uncontrolled water flow. To minimize the negative consequences of pipe bursts, an early detection is necessary. This paper describes a heuristic burst detection method, which continuously compares forecasted and measured values of the water demand. The forecasts of the water demand were generated by an adaptive water demand forecasting model. To test the method, a dataset of five years of water demand data in a supply area in the Western part of the Netherlands was collected. The method was tested on a subset of the data (only the winter months) in which 9 (larger) burst events were reported. The detection probability for the reported bursts was 44.4%, at an acceptable rate of false alarms of 5.0%. The results were compared with the CUSUM method, which is a …

Advanced Water Resources Engineering Lab

교수님 소개

Donghwi Jung

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Exploration of Deep Learning Leak Detection Model across Multiple Smart Water Distribution Systems: Detectable Leak Sizes with AMI Meters

Advancements in Multimodal Differential Evolution: A Comprehensive Review and Future Perspectives

Improving erosion resistance of sandy soils using zein biopolymer

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

Donghwi Jung

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Exploration of Deep Learning Leak Detection Model across Multiple Smart Water Distribution Systems: Detectable Leak Sizes with AMI Meters

Advancements in Multimodal Differential Evolution: A Comprehensive Review and Future Perspectives

Improving erosion resistance of sandy soils using zein biopolymer

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집