Physical Sciences and Mathematics Commons^™

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. …

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 …

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

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 …

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 …

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 …

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 …

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

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

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) …

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. …

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 …

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 …

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 …

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

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 …

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 …

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 …

Reducing Carbon Emission Of Ocean Shipments By Optimizing Container Size Selection, Edwin Lik Ming Chong, Nang Laik Ma, Kar Way Tan

Research Collection School Of Computing and Information Systems

Human’s impact on earth through global warming is more or less an accepted fact. Ocean freight is estimated to contribute 4-5% of global carbon emissions and manufacturing companies can aid in reducing this amount. Many companies that ship goods through full container loads do not have the capabilities to ensure the containers they are using minimizes their carbon footprint. One of the reasons is the choice of non-ideal container sizes for their shipments. This paper provides a mathematical model to minimize companies’ shipping carbon footprints by selecting the ideal container sizes appropriate for their shipment volumes. Using data from a …

Organic Fluids And Passive Cooling In A Supercritical Rankine Cycle For Power Generation From Low Grade Heat Sources, Rachana Vidhi

USF Tampa Graduate Theses and Dissertations

Low grade heat sources have a large amount of thermal energy content. Due to low temperature, the conventional power generation technologies result in lower efficiency and hence cannot be used. In order to efficiently generate power, alternate methods need to be used. In this study, a supercritical organic Rankine cycle was used for heat source temperatures varying from 125°C to 200°C. Organic refrigerants with zero ozone depletion potential and their mixtures were selected as working fluid for this study while the cooling water temperature was changed from 10-25°C. Operating pressure of the cycle has been optimized for each fluid at …

An Integral Framework For Sustainable Building Design, Bushra Asfari

Masters Theses

Selection of materials for building design is a delicate process hinged of a number of factors which can be cost or environmental related, depending on the objectives of the design. This process becomes more difficult when designers are faced with several material options for each building component. This thesis presents the design and development of a framework that enables designers understand the trade-off between cost and environmental related factors when selecting materials for building design. The framework is based on the integration of Autodesk Revit, Microsoft access, and modeling modified Harmony search multi-objective optimization tool adapted to account for material …

Optimal Acceleration Thresholds For Non-Holonomic Agents, Brian Ricks, Parris K. Egbert

Computer Science Faculty Publications

Finding optimal trajectories for non-accelerating, non-holonomic agents is a well-understood problem. However, in video games, robotics, and crowd simulations non-holonomic agents start and stop frequently. With the vision of improving crowd simulation, we find optimal paths for virtual agents accelerating from a standstill. These paths are designed for the “ideal”, initial stage of planning when obstacles are ignored. We analytically derive paths and arrival times using arbitrary acceleration angle thresholds. We use these paths and arrival times to find an agent’s optimal ideal path. We then numerically calculate the decision surface that can be used by an application at run-time …

Groundwater Flow Model, Optimal Management Model, And Advective Transport Model For The Mississippi River Valley Alluvial Aquifer In Cache Critical Groundwater Area, Arkansas, Haveen Muhammed Rashid

Theses and Dissertations

A three dimensional finite difference model for part of the Mississippi River Valley alluvial aquifer in the cache critical groundwater area of eastern Arkansas was constructed to simulate potential future conditions of groundwater flow. The model was calibrated using Parameter Estimation code (PEST). Additional calibration was achieved using the pilot point with regularization and singular value decomposition (SVD assist). The model was calibrated using 2,322 hydraulic head measurements for the years 2000 to 2010 from 150 observation wells located in the study area. Hydraulic conductivity values from the pilot point calibration ranged between 42 and 173 m/d. Specific yield values …

Waveforms For Optimal Sub-Kev High-Order Harmonics With Synthesized Two- Or Three-Colour Laser Fields, Cheng Jin, Guoli Wang, Hui Wei, Anh-Thu Le, C. D. Lin

Physics Faculty Research & Creative Works

High-order harmonics extending to the X-ray region generated in a gas medium by intense lasers offer the potential for providing tabletop broadband light sources but so far are limited by their low conversion efficiency. Here we show that harmonics can be enhanced by one to two orders of magnitude without an increase in the total laser power if the laser's waveform is optimized by synthesizing two- or three-colour fields. The harmonics thus generated are also favourably phase-matched so that radiation is efficiently built up in the gas medium. Our results, combined with the emerging intense high-repetition MHz lasers, promise to …

Poisson Distributed Individuals Control Charts With Optimal Limits, Negin Enayaty Ahangar

Graduate Theses and Dissertations

The conventional method used in attribute control charts is the Shewhart three sigma limits. The implicit assumption of the Normal distribution in this approach is not appropriate for skewed distributions such as Poisson, Geometric and Negative Binomial. Normal approximations perform poorly in the tail area of the these distributions. In this research, a type of attribute control chart is introduced to monitor the processes that provide count data. The economic objective of this chart is to minimize the cost of its errors which is determined by the designer. This objective is a linear function of type I and II errors. …

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

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 …

Using Prior Knowledge And Learning From Experience In Estimation Of Distribution Algorithms, Mark Walter Hauschild

Dissertations

Estimation of distribution algorithms (EDAs) are stochastic optimization techniques that explore the space of potential solutions by building and sampling explicit probabilistic models of promising candidate solutions. One of the primary advantages of EDAs over many other stochastic optimization techniques is that after each run they leave behind a sequence of probabilistic models describing useful decompositions of the problem. This sequence of models can be seen as a roadmap of how the EDA solves the problem. While this roadmap holds a great deal of information about the problem, until recently this information has largely been ignored. My thesis is that …

R Code To Accompany “Principal Component Analysis And Optimization: A Tutorial”, Robert Reris, J. Paul Brooks

Statistical Sciences and Operations Research Data

This data accompanies "Principal Component Analysis and Optimization: A Tutorial" by Robert Reris and J. Paul Brooks, presented at the 2015 INFORMS Computing Society Conference, Operations Research and Computing: Algorithms and Software for Analytics, Richmond, Virginia January 11-13, 2015.

The data contains R code, output, and comments that follow the examples for principal component analysis in the paper.

A Distributed Consensus Algorithm For Decision Making In Service-Oriented Internet Of Things, Shancang Li, George Oikonomou, Theo Tryfonas, Thomas M. Chen, Li Da Xu

Information Technology & Decision Sciences Faculty Publications

In a service-oriented Internet of things (IoT) deployment, it is difficult to make consensus decisions for services at different IoT edge nodes where available information might be insufficient or overloaded. Existing statistical methods attempt to resolve the inconsistency, which requires adequate information to make decisions. Distributed consensus decision making (CDM) methods can provide an efficient and reliable means of synthesizing information by using a wider range of information than existing statistical methods. In this paper, we first discuss service composition for the IoT by minimizing the multi-parameter dependent matching value. Subsequently, a cluster-based distributed algorithm is proposed, whereby consensuses are …