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Articles 1 - 29 of 29
Full-Text Articles in Physical Sciences and Mathematics
Abm Simulation Model Of A Pandemic For Optimizing Vaccination Strategy, Gibeom Park
Abm Simulation Model Of A Pandemic For Optimizing Vaccination Strategy, Gibeom Park
Theses and Dissertations
This study presents a process-oriented hybrid model for individuals' immune responses and interactions involving vaccination to describe the trend of contagious disease and estimate the future societal cost. The model considers "recovery" as a non-absorbing state and incorporates various infection stage states including two symptomatic states. To model contagiousness to be consistent with the current pandemic and include that the spread of a disease depends on the mobility of people, we developed an Agent-Based Simulator that fitted to the particular model used in this study and can test various what-if scenarios. We improved the simulator considerably by appying data structures …
Gradient Estimation For Attractor Networks, Thomas Flynn
Gradient Estimation For Attractor Networks, Thomas Flynn
Dissertations, Theses, and Capstone Projects
It has been hypothesized that neural network models with cyclic connectivity may be more powerful than their feed-forward counterparts. This thesis investigates this hypothesis in several ways. We study the gradient estimation and optimization procedures for several variants of these networks. We show how the convergence of the gradient estimation procedures are related to the properties of the networks. Then we consider how to tune the relative rates of gradient estimation and parameter adaptation to ensure successful optimization in these models. We also derive new gradient estimators for stochastic models. First, we port the forward sensitivity analysis method to the …
Computational Methods In Civil Engineering, Nir Krakauer
Computational Methods In Civil Engineering, Nir Krakauer
Open Educational Resources
No abstract provided.
Optimizing Bio-Retention Locations For Stormwater Management Using Genetic Algorithm, Dieu Huong Trinh, Ting Fong May Chui
Optimizing Bio-Retention Locations For Stormwater Management Using Genetic Algorithm, Dieu Huong Trinh, Ting Fong May Chui
International Conference on Hydroinformatics
To minimize the change of hydrological regime due to urbanization, stormwater best management practices have been enforced in the past few decades in certain urban areas. One approach is to implement small-scale hydrologic controls, such as bio-retention systems, throughout a catchment. Optimization techniques have also been applied to determine the locations that give the most hydrological benefits. However, optimization tools are commonly built in together with specific hydrological models. Thus, the choices and components of hydrological models are usually restricted. Furthermore, it is redundant to build another hydrological model that has a built-in optimization tool if a hydrological model, and …
Real-Time Water Decision Support Services For Droughts, Tingting Zhao, Barbara Minsker, Jong Lee, Fernando Salas, David R. Maidment, Cedric David
Real-Time Water Decision Support Services For Droughts, Tingting Zhao, Barbara Minsker, Jong Lee, Fernando Salas, David R. Maidment, Cedric David
International Conference on Hydroinformatics
Through application of computational methods and an integrated information system, real-time data and river modeling systems can help decision makers identify more effective actions for management practice. The purpose of this study is to develop a real-time decision support model to recommend optimal curtailments during water shortages for decision makers. To enable ease of use and re-use, the workflows (i.e., analysis and model steps) of the real-time decision support model are published as Web services delivered through an internet browser, including model inputs, a published workflow service, and visualized outputs. The model consists of two major components: the real-time river …
Parameter Calibration Method Based On Ga Technique For Multi-Event, Yeonjoo Kim, Eun-Sung Chung, Kwangjai Won, Byungho Kong, Kyungil Gil
Parameter Calibration Method Based On Ga Technique For Multi-Event, Yeonjoo Kim, Eun-Sung Chung, Kwangjai Won, Byungho Kong, Kyungil Gil
International Conference on Hydroinformatics
Accurate parameter estimation based catchment modeling systems requires considerable work to establish credibility. In this paper, a methodology for parameter estimation of hydrologic simulation model is proposed to simultaneously include several rainfall events using Shannon entropy. The proposed methodology uses Genetic Algorithm(GA) optimization techniques for the Storm Water Management Model (SWMM). Shannon entropy theory was applied to calculate weights according to each rainfall event in study area. A case study application was undertaken using the Milyang-dam basin, in Korea. Three events are applied to calculate Shannon entropy weights. Then, Nash-Sutcliffe Efficiency(NSE) & Root Mean Square Error(RMSE) are compared with those …
Short-Term Optimization Model With Esp Forecasts For Columbia Hydropower System With Optimized Multi-Turbine Powerhouses, Jery R. Stedinger, Sue Nee Tan, Christine A. Shoemaker, Jonathan R. Lamontagne, Steven B. Barton
Short-Term Optimization Model With Esp Forecasts For Columbia Hydropower System With Optimized Multi-Turbine Powerhouses, Jery R. Stedinger, Sue Nee Tan, Christine A. Shoemaker, Jonathan R. Lamontagne, Steven B. Barton
International Conference on Hydroinformatics
Hydroelectric generation is the major source of electric energy in the Pacific Northwestern region of the United States, and efficient operation of that system while meeting environmental constraints and reserve capacity demands is an important economic, environmental, and social issue. This paper describes efforts to develop a new stochastic short-term scheduling model (with perhaps a 3-week planning horizon) for the ten major reservoirs operated by the federal Bonneville Power Administration (BPA) on the Columbia and Snake River systems. The analysis incorporates time-delays (up to 24 hours in a model with time steps increasing from 6 hours initially perhaps to 24 …
Optimized Use Of Water From Multiple Sources In Micro Water Grid Systems: A Modeling Approach, Hyeongrak Cho, Jungwoo Jung, Sangho Lee, Soo Kwen Chae
Optimized Use Of Water From Multiple Sources In Micro Water Grid Systems: A Modeling Approach, Hyeongrak Cho, Jungwoo Jung, Sangho Lee, Soo Kwen Chae
International Conference on Hydroinformatics
Micro water grid (MWG) is a novel approach to allow high reliability, diversification of water sources, low energy consumption, and cost reduction. Although it is not well-defined, it has potential for efficient management of urban water. MWG is suitable for use in small-scale buildings and towns, which have various uses of water produced from multiple source waters. Accordingly, design of MWG is challenging without proper tools to predict its performance. This research focused on the development and application of a model for optimized use of water from multiple sources in MWG systems. The model was comprised of two modules including …
A Hybrid Optimization Method For Real-Time Pump-Scheduling, Valeria Puleo, Mark Morley, Gabriele Freni, Dragan A. Savić
A Hybrid Optimization Method For Real-Time Pump-Scheduling, Valeria Puleo, Mark Morley, Gabriele Freni, Dragan A. Savić
International Conference on Hydroinformatics
Linear, non-linear and dynamic programming, heuristics and evolutionary computation are amongst the techniques which have been applied to obtain solutions to optimal pump-scheduling problems. Most of these either greatly simplify the complex water distribution system or require significant time to solve the problem. The scheduling of pumps is frequently undertaken in near-real time, in order to minimize cost and maximize energy savings. However, this requires a computationally efficient algorithm that can rapidly identify an acceptable solution. In this paper, a hybrid optimization model is presented, coupling Linear Programming and Genetic Algorithms. The resulting hybrid optimization model has demonstrated more rapid …
Optimal Rehabilitation Strategy In Water Distribution Systems Considering Reduction In Greenhouse Gas Emissions, Farshid Rahmani, Abdollah Ardeshir, Kourosh Behzadian, Fatemeh Jalilsani
Optimal Rehabilitation Strategy In Water Distribution Systems Considering Reduction In Greenhouse Gas Emissions, Farshid Rahmani, Abdollah Ardeshir, Kourosh Behzadian, Fatemeh Jalilsani
International Conference on Hydroinformatics
Most of water distribution systems (WDS) need rehabilitation due to aging infrastructure leading to decreasing capacity, increasing leakage and consequently low performance of the WDS. However an appropriate strategy including location and time of pipeline rehabilitation in a WDS with respect to a limited budget is the main challenge which has been addressed frequently by researchers and practitioners. On the other hand, selection of appropriate rehabilitation technique and material types is another main issue which has yet to address properly. The latter can affect the environmental impacts of a rehabilitation strategy meeting the challenges of global warming mitigation and consequent …
Real-Time Reservoir Operation For Drought Management Considering Ensemble Streamflow Predictions Derived From Operational Forecasts Of Precipitation In Japan, Daisuke Nohara, Tomoharu Hori
Real-Time Reservoir Operation For Drought Management Considering Ensemble Streamflow Predictions Derived From Operational Forecasts Of Precipitation In Japan, Daisuke Nohara, Tomoharu Hori
International Conference on Hydroinformatics
Ensemble hydrological predictions are considered to be useful for robust reservoir operation as they include multiple possible hydrological scenarios in the future as well as dispersion of the predictions, from which the degree of prediction uncertainty can be estimated. Although operational ensemble hydrological predictions have been available in many regions, they have not yet been widely used in the actual reservoir management due to the difficulty in the handling such complex information. In order to facilitate effective utilization of ensemble hydrological predictions in the actual reservoir management, a real-time reservoir operation method for drought management is developed considering operational ensemble …
Short-Term Optimization Of A Canal Network For Navigation And Water Management, Arnejan Van Loenen, Min Xu, Robin Engel
Short-Term Optimization Of A Canal Network For Navigation And Water Management, Arnejan Van Loenen, Min Xu, Robin Engel
International Conference on Hydroinformatics
We present the design, implementation and operational use of a short-term optimization approach for the operational water management of the Twentekanalen canal system for navigation and water resources management. The system was originally designed for navigation and its construction had been completed in 1938. In the past decades, it also became increasingly important for the regional water management. In summer periods, the system provides the region with fresh water and helps to drain the area otherwise. The short-term optimization is implemented in the Operational Monitoring System for the National Regulated Water Systems for advising the operating staff on the operation …
Model-Based Sectorization Of Water Distribution Networks For Increased Energy Efficiency, Mario E. Castro Gama, Pan Quan, Andreja Jonoski, Carlo Chiesa
Model-Based Sectorization Of Water Distribution Networks For Increased Energy Efficiency, Mario E. Castro Gama, Pan Quan, Andreja Jonoski, Carlo Chiesa
International Conference on Hydroinformatics
Efficient management of water supply systems is nowadays one of the most important challenges for water utilities. Common efficiency gains in such systems can be achieved by reducing the leakages and by reducing the energy consumption. For the case of minimization of energy consumption a new technique for sectorization and efficient pressure management is presented, based on water distribution modeling and optimization. The technique is applicable to situations when energy consumption reduction can be achieved by dividing a large Pressure Management Zone (PMZ) in smaller, but more efficient PMZs, or sectors. It consists of three steps: 1) An initial selection …
Flood Resilience Assessment In Urban Drainage Systems Through Multi-Objective Optimisation, Carlos Martínez-Cano, Beheshtah Toloh, Arlex Sanchez-Torres, Zoran Vojinović, Damir Brdjanovic
Flood Resilience Assessment In Urban Drainage Systems Through Multi-Objective Optimisation, Carlos Martínez-Cano, Beheshtah Toloh, Arlex Sanchez-Torres, Zoran Vojinović, Damir Brdjanovic
International Conference on Hydroinformatics
In future years, economic development, urbanisation and heavy rainfall events are expected to increase in urban areas, in particular in developing countries. It is well known that urban development has a strong impact on the water cycle such as increase of flood peaks and volume, decrease of base flow, hydraulic stress and water pollution. Resilience measures are still needed to improve urban flood risk, the possibilities to provide indicators that could be used to characterize urban resilience related to flooding is outmost importance. The work described here presents an optimisation framework for urban drainage rehabilitation that incorporates in the decision …
Using Multi-Scale Uncertainty Information And Specific Forecast Skill To Improve Reservoir Operations, Thomas S. Lowry, Nathalie Voisin, Mark S. Wigmosta
Using Multi-Scale Uncertainty Information And Specific Forecast Skill To Improve Reservoir Operations, Thomas S. Lowry, Nathalie Voisin, Mark S. Wigmosta
International Conference on Hydroinformatics
Optimization of reservoir operations to time series of forecasted inflows are constrained by a set of multiple objectives that span many time scales, however the temporally evolving skill of the forecasts are usually not considered in the objective functions. For example, a flow forecast time series extending from 1 day to 6 months consists of a medium range flow forecast that draws its skill from initial conditions and weather forecasts and a seasonal flow forecast that relies on the initial conditions only. The skill of the medium range flow forecast is the daily and aggregated values with a range of …
Hybrid Control-Oriented Modeling Of Combined Sewer Networks: Barcelona Case Study, Bernat Joseph-Duran, Carlos Ocampo-Martinez, Gabriela Cembrano
Hybrid Control-Oriented Modeling Of Combined Sewer Networks: Barcelona Case Study, Bernat Joseph-Duran, Carlos Ocampo-Martinez, Gabriela Cembrano
International Conference on Hydroinformatics
A hybrid linear model for real-time optimization-based control of a combined sewer network has been developed to be used for the minimization of pollution during storm events. The model takes into account delays and attenuation in sewers together with piecewise linear approximations for flow over weirs, overflows in junctions and flow re-entering the network after overflows. Using the proposed model, an Optimal Control Problem (OCP) is formulated, which can be efficiently solved by means of a mixed integer linear or quadratic programming problem. The performance of a Model Predictive Control (MPC) strategy solving consecutive OCPs is assessed by means of …
Efficient Methods For Optimizing Hydropower Under Uncertainty, Timothy Michael Magee Jr., Edith A. Zagona, Mitch Clement
Efficient Methods For Optimizing Hydropower Under Uncertainty, Timothy Michael Magee Jr., Edith A. Zagona, Mitch Clement
International Conference on Hydroinformatics
There are several sources of uncertainty in scheduling hydropower: reservoir inflows, power generation, demand and value, and the value of water remaining in storage at the end of the planning horizon. RiverWare is an object oriented modeling tool widely used for the operations and planning of large and small systems of reservoirs. Typically, short term optimization of hydropower is complicated by the need to meet a wide variety of prioritized non-power constraints and RiverWare is designed to satisfy these constraints to the extent possible. We present four different approaches that use deterministic methods combined with uncertainty models to efficiently optimize …
Optimization Of Groundwater Remediation With New Efficient Parallel Algorithm For Global Optimization, Min Pang, Christine A. Shoemaker
Optimization Of Groundwater Remediation With New Efficient Parallel Algorithm For Global Optimization, Min Pang, Christine A. Shoemaker
International Conference on Hydroinformatics
Application of optimization algorithm to PDE modeling groundwater remediation can greatly reduce remediation cost. However, groundwater remediation analysis requires a computational expensive simulation, therefore, effective parallel optimization could potentially greatly reduce computational expense. The optimization algorithm used in this research is Parallel Stochastic radial basis function. This is designed for global optimization of computationally expensive functions with multiple local optima and it does not require derivatives. In each iteration of the algorithm, an RBF is updated based on all the evaluated points in order to approximate expensive function. Then the new RBF surface is used to generate the next set …
An Optimization Model For Prioritizing Sewerage Maintenance Scheduling, Juan David Torres Turriago, Juan Pablo Rodriguez, Juan David Palacio
An Optimization Model For Prioritizing Sewerage Maintenance Scheduling, Juan David Torres Turriago, Juan Pablo Rodriguez, Juan David Palacio
International Conference on Hydroinformatics
Water utility companies, responsible for providing water supply and sewerage services to the urban population, are constantly seeking to improve their service.In the case of sewer systems, effective scheduling of preventive maintenance of urban water infrastructure has been identified as an important activity in order to reduce costs and protect the integrity of citizens and the surrounding, both built and natural, environments. Consequently, with particular focus on Bogotá (Colombia), we developed an optimization model that generates a preventive maintenance plan on a set of zones withinthe city. These zones have in common a high failure probability over a defined time …
Short-Term Hydropower Optimization Using A Time-Decomposition Algorithm, Jonathan R. Lamontagne, Jery Russell Stedinger
Short-Term Hydropower Optimization Using A Time-Decomposition Algorithm, Jonathan R. Lamontagne, Jery Russell Stedinger
International Conference on Hydroinformatics
Hydropower operations optimization models select a sequence of releases from one or more reservoirs that maximizes the expected benefit while honoring many social and environmental constraints. A 3-tiered time-decomposition algorithm is adopted to compute optimal sub-daily releases for the Harris Station reservoir in Maine, USA. This involves solving nested optimization models, each with a different planning horizon and time-step, where the longer-term planning models inform the shorter-term models. This allows for rapid optimization of short-term operations, while efficiently considering seasonal objectives and constraints. In the case study presented, 6-hr release decisions in a weekly model are made by iteratively solving …
A Simulation Based Optimal Control System For Water Resources, Asier Lacasta, Mario Morales-Hernández, Pilar Brufau, Pilar García-Navarro
A Simulation Based Optimal Control System For Water Resources, Asier Lacasta, Mario Morales-Hernández, Pilar Brufau, Pilar García-Navarro
International Conference on Hydroinformatics
Nowadays, the increasing demand of water resources has become one of the most relevant issues when water supply must be guaranteed as in the case of irrigation comunities. It becomes difficult to provide the predictive optimal behavior of regulation structures when the regime of the flow is changing in time and, moreover, when this regulation modifies the hydraulic conditions of the structure. One of the most widely used solution for control is PID. The disadvantages of PID control are the difficulties in the presence of non-linearities as well as the PID parameters tuning. Taking into account previous works about sluice …
Swmm5-Ea – A Tool For Learning Optimization Of Urban Drainage And Sewerage Systems With Genetic Algorithms, Assela Pathirana
Swmm5-Ea – A Tool For Learning Optimization Of Urban Drainage And Sewerage Systems With Genetic Algorithms, Assela Pathirana
International Conference on Hydroinformatics
In spite of the developments in the application of evolutionary algorithms in the urban water sector, it is not widely used by practitioners in their day to day work. A reason for this underutilization is the lack of accessible optimization tools. The available limited options, on the one extreme, are characterized by tools for very specific applications (e.g. pipe sizing): While these provide useful optimization applications in specific domains, they are too restrictive in the range of application. The other extreme is to `glue-together’ a general purpose EA library and other required algorithms (e.g. an urban drainage simulation model) using …
Multi-Objective Pipe Smoothing Genetic Algorithm For Water Distribution Network Design, Matthew Barrie Johns, Edward C. Keedwell, Dragan A. Savić
Multi-Objective Pipe Smoothing Genetic Algorithm For Water Distribution Network Design, Matthew Barrie Johns, Edward C. Keedwell, Dragan A. Savić
International Conference on Hydroinformatics
This paper describes the formulation of a Multi-objective Pipe Smoothing Genetic Algorithm (MOPSGA) and its application to the least cost water distribution network design problem. Evolutionary Algorithms have been widely utilised for the optimisation of both theoretical and real-world non-linear optimisation problems, including water system design and maintenance problems. In this work we present a pipe smoothing based approach to the creation and mutation of chromosomes which utilises engineering expertise with the view to increasing the performance of the algorithm whilst promoting engineering feasibility within the population of solutions. MOPSGA is based upon the standard Non-dominated Sorting Genetic Algorithm-II (NSGA-II) …
A Novel Decision Support System For Optimized Sewer Infrastructure Asset Management, Ben Ward, Dragan A. Savić
A Novel Decision Support System For Optimized Sewer Infrastructure Asset Management, Ben Ward, Dragan A. Savić
International Conference on Hydroinformatics
This paper approaches the sewerage asset management challenge from a UK perspective by outlining a comprehensive methodology capable of optimising the performance of sewerage infrastructure networks using a series of Hydroinformatic tools. In order to define, evaluate and forecast the future performance of sewerage assets, a unique deterioration model is established to predict the future condition of the network. The model analyses historic CCTV survey information to identify deterioration trends based on key pipe characteristics. Against, this improved understanding of past, current and future condition, a collapse rate is predicted by correlating historic failures against the observed sewer condition profiles. …
An Optimization And Decision Support Tool For Long-Term Strategies In The Transformation Of Urban Water Infrastructure, Theo G. Schmitt, Silja Worreschk, Inka Kaufmann Alves, Frank Herold, Clemens Thielen
An Optimization And Decision Support Tool For Long-Term Strategies In The Transformation Of Urban Water Infrastructure, Theo G. Schmitt, Silja Worreschk, Inka Kaufmann Alves, Frank Herold, Clemens Thielen
International Conference on Hydroinformatics
Predicted climatic, demographic and socio-economic developments cause major adaptions of urban water infrastructures. The central water supply and wastewater systems in Europe do not meet the increased requirements of resource efficiency and sustainability anymore. Especially in rural areas predicted demographic change and the particular differentiated settlement structure affect the functionality of present water infrastructures. These new challenges require extensive and flexible adaptions or even a long-term and dynamic system change of urban infrastructures. These long-term transformations of infrastructure systems require the design of innovative strategies. In the project presented, environmental engineers together with city planners, mathematicians and computer scientists develop …
Effective Data Management Enables Intelligent Utility Management, Gary L.S. Wong
Effective Data Management Enables Intelligent Utility Management, Gary L.S. Wong
International Conference on Hydroinformatics
Instrumentation and automation plays a vital role to managing the water industry. These systems generate vast amounts of data that must be effectively managed in order to enable intelligent decision making. Time series data management software, commonly known as data historians are used for collecting and managing real-time (time series) information. More advanced software solutions provide a data infrastructure or utility wide Operations Data Management System (ODMS) that stores, manages, calculates, displays, shares, and integrates data from multiple disparate automation and business systems that are used daily in water utilities. These ODMS solutions are proven and have the ability to …
Development Of A Model-Based Decision Support System For Water Treatment In Smart Micro Water Grid, Hyeongrak Cho, Jungwoo Jung, Sangho Lee, Soo Kwen Chae
Development Of A Model-Based Decision Support System For Water Treatment In Smart Micro Water Grid, Hyeongrak Cho, Jungwoo Jung, Sangho Lee, Soo Kwen Chae
International Conference on Hydroinformatics
Micro water grid (MWG) is an emerging concept for decentralized water management system for residential, industrial, commercial, and institutional buildings. MWG achieves specific local goals, such as reliability, diversification of water sources, and cost reduction. Unlike micro electricity grid, MWG has not been well-established, leading to a problem of initial design and operation. Thus, a MWG system requires a “smart” infrastructure that allows autonomous control and regulation. In this study, a decision support system (DSS) was designed to select optimum combinations of water treatment unit processes in MWG. To begin, key questions on water treatment in MWG systems were identified. …
Economic Growth Assumptions In Climate And Energy Policy, Nir Y. Krakauer
Economic Growth Assumptions In Climate And Energy Policy, Nir Y. Krakauer
Publications and Research
The assumption that the economic growth seen in recent decades will continue has dominated the discussion of future greenhouse gas emissions and the mitigation of and adaptation to climate change. Given that long-term economic growth is uncertain, the impacts of a wide range of growth trajectories should be considered. In particular, slower economic growth would imply that future generations will be relatively less able to invest in emissions controls or adapt to the detrimental impacts of climate change. Taking into consideration the possibility of economic slowdown therefore heightens the urgency of reducing greenhouse gas emissions now by moving to renewable …
Scheduling And Resource Allocation In Wireless Sensor Networks, Yosef Alayev
Scheduling And Resource Allocation In Wireless Sensor Networks, Yosef Alayev
Dissertations, Theses, and Capstone Projects
In computer science and telecommunications, wireless sensor networks are an active research area. Each sensor in a wireless sensor network has some pre-defined or on demand tasks such as collecting or disseminating data. Network resources, such as broadcast channels, number of sensors, power, battery life, etc., are limited. Hence, a schedule is required to optimally allocate network resources so as to maximize some profit or minimize some cost. This thesis focuses on scheduling problems in the wireless sensor networks environment. In particular, we study three scheduling problems in the wireless sensor networks: broadcast scheduling, sensor scheduling for area monitoring, and …