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Publications and open acccess preprints of my publications are listed below. Click on [Abstract] to obtain more information. Bibliographical information is available by clicking on [BibTeX].

You can search in the abstracts using the quicksearch box below. The official publication pages can be accessed through the link given [DOI]. If a preprint version is available it can be found by clicking on [URL]. Links to press coverage are listed under [Comment].

A list of my publications is also available on Google Scholar.


Kaandorp C, Pesoa Moreno I, Pesch U, van de Giesen N and Abraham E (2024), "‘Commoning practices’ for energy justice? Perspectives on the heat transition in the city of Amsterdam", Energy Research & Social Science. Vol. 108, pp. 103369.
Abstract: Decarbonisation of the built environment is needed to abate the use of fossil fuels and greenhouse gas emissions. In the city of Amsterdam, multiple bottom-up initiatives have been initiated to reach these goals. In this paper, we explore how energy justice is reshaped by these initiatives on an urban scale. This is done by a case study on a platform that aims to connect, support and inform community energy initiatives. Based on ethnographic fieldwork performed between 2019 and 2022 on the heat transition in Amsterdam, we describe how relations between governmental bodies, businesses and urban residents are contested through this platform. Additionally, we describe how the platform shapes the access of citizens to decision-making spaces, financial tools and information to foster new forms of local autonomy, physical heating infrastructures and decision-making procedures. By analysing the motivations and activities for increasing users’ influence and ownership of resources with the notion of ‘commoning practices’, we show how activities of the platform do not only shape physical heating infrastructures, but also the decision-making processes for achieving low-carbon and renewable heating systems in Amsterdam. We, therefore, propose that the notion of ‘commoning practices’ can be used in future research to contribute to a dynamic understanding of how energy justice concerns are expressed and shaped in practice.
BibTeX:
@article{Kaandorp2024,
title = {‘Commoning practices’ for energy justice? Perspectives on the heat transition in the city of Amsterdam},
journal = {Energy Research & Social Science},
volume = {108},
pages = {103369},
year = {2024},
issn = {2214-6296},
doi = {https://doi.org/10.1016/j.erss.2023.103369},
url = {https://www.sciencedirect.com/science/article/pii/S2214629623004292},
author = {Chelsea Kaandorp and Igor T. Moreno Pessoa and Udo Pesch and Nick {van de Giesen} and Edo Abraham},
keywords = {Decarbonisation of the built environment, Energy justice, Commoning practices, Community energy, Urban commons, Urban anthropology}
}
Geleijnse J, Rutten M, de Villiers D, Bamwenda JT and Abraham E (2023), "Enhancing water access monitoring through mapping multi-source usage and disaggregated geographic inequalities with machine learning and surveys", Scientific Reports. Vol. 13(1), pp. 13433. Nature Publishing Group UK London.
Abstract: Monitoring safe water access in developing countries relies primarily on household health survey and census data. These surveys are often incomplete: they tend to focus on the primary water source only, are spatially coarse, and usually happen every 5-10 years, during which significant changes can happen in urbanisation and infrastructure provision, especially in sub Saharan Africa. In this work, we present a data-driven approach that utilises and compliments survey based data of water access, to provide context-specific and disaggregated monitoring. The level of access to improved water and sanitation has been shown to vary with geographical inequalities related to the availability of water resources and terrain, population density and socio-economic determinants such as income and education. We use such data and successfully predict the level of water access in areas for which data is lacking, providing spatially explicit and community level monitoring possibilities for mapping geographical inequalities in access. This is showcased by applying three machine learning models that use such geographical data to predict the number of presences of water access points of eight different access types across Uganda, with a 1km by 1km grid resolution. Two Multi-Layer-Perceptron (MLP) models and a Maximum Entropy (MaxEnt) model are developed and compared, where the former are shown to consistently outperform the latter. The best performing Neural Network model achieved a True Positive Rate of 0.89 and a False Positive Rate of 0.24, compared to 0.85 and 0.46 respectively for the MaxEnt model. The models improve on previous work on water point modeling through the use of neural networks, in addition to introducing the True Positive - and False Positive Rate as better evaluation metrics to also assess the MaxEnt model. We also present a scaling method to move from predicting only the relative probability of water point presences, to predicting the absolute number of presences. To challenge both the model results and the more standard health surveys, a new household level survey is carried out in Bushenyi, a mid-sized town in the South-West of Uganda, asking specifically about the multitude of water sources. On average Bushenyi households reported to use 1.9 water sources. The survey further showed that the actual presence of a source, does not always imply that it is used. Therefore it is no option to rely solely on models for water access monitoring. For this, household surveys remain necessary but should be extended with questions on the multiple sources that are used by households. </tr>
BibTeX:
@article{Geleijnse2023,
  author = {Geleijnse, Jan and Rutten, Martine and de Villiers, Didier and Bamwenda, James Tayebwa and Abraham, Edo},
  title = {Enhancing water access monitoring through mapping multi-source usage and disaggregated geographic inequalities with machine learning and surveys},
  journal = {Scientific Reports},
  publisher = {Nature Publishing Group UK London},
  year = {2023},
  volume = {13},
  number = {1},
  pages = {13433}
}
Alloul A, Moradvandi A, Puyol D, Molina R, Gardella G, Vlaeminck SE, De Schutter B, Abraham E, Lindeboom RE and Weissbrodt DG (2023), "A novel mechanistic modelling approach for microbial selection dynamics: Towards improved design and control of raceway reactors for purple bacteria", Bioresource Technology. Vol. 390, pp. 129844. Elsevier.
Abstract: Purple phototrophic bacteria (PPB) show an underexplored potential for resource recovery from wastewater. Raceway reactors offer a more affordable full-scale solution on wastewater and enable useful additional aerobic processes. Current mathematical models of PPB systems provide useful mechanistic insights, but do not represent the full metabolic versatility of PPB and thus require further advancement to simulate the process for technology development and control. In this study, a new modelling approach for PPB that integrates the photoheterotrophic, and both anaerobic and aerobic chemoheterotrophic metabolic pathways through an empirical parallel metabolic growth constant was proposed. It aimed the modelling of microbial selection dynamics in competition with aerobic and anaerobic microbial community under different operational scenarios. A sensitivity analysis was carried out to identify the most influential parameters within the model and calibrate them based on experimental data. Process perturbation scenarios were simulated, which showed a good performance of the model.
BibTeX:
@article{Alloul2023,
  author = {Alloul, Abbas and Moradvandi, Ali and Puyol, Daniel and Molina, Raúl and Gardella, Giorgio and Vlaeminck, Siegfried E and De Schutter, Bart and Abraham, Edo and Lindeboom, Ralph EF and Weissbrodt, David G},
  title = {A novel mechanistic modelling approach for microbial selection dynamics: Towards improved design and control of raceway reactors for purple bacteria},
  journal = {Bioresource Technology},
  publisher = {Elsevier},
  year = {2023},
  volume = {390},
  pages = {129844}
}
Mulugetta Y, Sokona Y, Trotter PA, Fankhauser S, Omukuti J, Somavilla Croxatto L, Steffen B, Tesfamichael M, Abraham E, Adam J-P, et al (2022), "Africa needs context-relevant evidence to shape its clean energy future", Nature Energy.
Abstract: Aligning development and climate goals means Africa's energy systems will be based on clean energy technologies in the long term, but pathways to get there are uncertain and variable across countries. Although current debates about natural gas and renewables in Africa are heated, they largely ignore the substantial context specificity of the starting points, development objectives and uncertainties of each African country's energy system trajectory. Here we---an interdisciplinary and majority African group of authors---highlight that each country faces a distinct solution space and set of uncertainties for using renewables or fossil fuels to meet its development objectives. For example, Ethiopia is headed for an accelerated green-growth pathway, but Mozambique is at a crossroads of natural gas expansion with implicit large-scale technological, economic, financial and social risks and uncertainties. We provide geopolitical, policy, finance and research recommendations to create firm country-specific evidence to identify adequate energy system pathways for development and to enable their implementation.
BibTeX:
@article{Mulugetta2022,
  author = {Mulugetta, Yacob and Sokona, Youba and Trotter, Philipp A. and Fankhauser, Samuel and Omukuti, Jessica and Somavilla Croxatto, Lucas and Steffen, Bjarne and Tesfamichael, Meron and Abraham, Edo and Adam, Jean-Paul and Agbemabiese, Lawrence and Agutu, Churchill and Aklilu, Mekalia Paulos and Alao, Olakunle and Batidzirai, Bothwell and Bekele, Getachew and Dagnachew, Anteneh G. and Davidson, Ogunlade and Denton, Fatima and Diemuodeke, E. Ogheneruona and Egli, Florian and Gebresilassie, Eshetu Gebrekidan and Gebreslassie, Mulualem and Goundiam, Mamadou and Gujba, Haruna Kachalla and Hailu, Yohannes and Hawkes, Adam D. and Hirmer, Stephanie and Hoka, Helen and Howells, Mark and Isah, Abdulrasheed and Kammen, Daniel and Kemausuor, Francis and Khennas, Ismail and Kruger, Wikus and Malo, Ifeoma and Mofor, Linus and Nago, Minette and Nock, Destenie and Okereke, Chukwumerije and Ouedraogo, S. Nadia and Probst, Benedict and Schmidt, Maria and Schmidt, Tobias S. and Shenga, Carlos and Sokona, Mohamed and Steckel, Jan Christoph and Sterl, Sebastian and Tembo, Bernard and Tomei, Julia and Twesigye, Peter and Watson, Jim and Winkler, Harald and Yussuff, Abdulmutalib},
  title = {Africa needs context-relevant evidence to shape its clean energy future},
  journal = {Nature Energy},
  year = {2022},
  url = {https://doi.org/10.1038/s41560-022-01152-0},
  doi = {10.1038/s41560-022-01152-0}
}
Kaandorp C, Miedema T, Verhagen J, van de Giesen N and Abraham E (2022), "Reducing committed emissions of heating towards 2050: Analysis of scenarios for the insulation of buildings and the decarbonisation of electricity generation", Applied Energy. Vol. 325, pp. 119759.
Abstract: Infrastructure for heat provision in the built environment needs to change remarkably to support lowering carbon emissions and achieving climate mitigation targets before 2050. We propose a computational approach for finding a mix of heat options per neighbourhood that minimises cumulative carbon emissions between 2030 and 2050, referred to as committed emissions, while at the same time adhering to technological constraints at both the household and neighbourhood scales. To establish this approach, we integrated bottom-up heat demand modelling at neighbourhood scale with a mixed-integer non-linear optimisation problem. Nine scenarios with different pathways for the insulation of buildings and the decarbonisation in electricity generation were considered and applied to three neighbourhoods in the city of Amsterdam, the Netherlands. The results show that (i) the committed emissions are ten times lower between 2030 and 2050 in scenarios in which ambitious measures are taken for the insulation of buildings and the decarbonisation in electricity generation, (ii) only in these ‘ambitious scenarios’ low temperature heat systems, such as heat pumps and low temperature heat networks, are optimal solutions for minimising committed emissions, (iii) if less ambitious insulation and decarbonisation measures are taken, high temperature heat options can be part of the heat mix with lowest committed emissions, and (iv) the minimum heat density for low temperature heat networks is not always achieved, creating risks for carbon lock-ins when applying these heat networks. Our results clearly indicate that pathways for the retrofitting of buildings and the decarbonisation in electricity generation need to be taken into account jointly when designing renewable and low-carbon heat systems to optimally reduce carbon emissions towards 2050 and reduce future carbon lock-ins.
BibTeX:
@article{Kaandorp2022,
  author = {Chelsea Kaandorp and Tes Miedema and Jeroen Verhagen and Nick van de Giesen and Edo Abraham},
  title = {Reducing committed emissions of heating towards 2050: Analysis of scenarios for the insulation of buildings and the decarbonisation of electricity generation},
  journal = {Applied Energy},
  year = {2022},
  volume = {325},
  pages = {119759},
  url = {https://www.sciencedirect.com/science/article/pii/S0306261922010315},
  doi = {10.1016/j.apenergy.2022.119759}
}
van Lagen G, Abraham E and Esfahani PM (2022), "A Bayesian Approach for Active Fault Isolation With an Application to Leakage Localization in Water Distribution Networks", IEEE Transactions on Control Systems Technology. , pp. 1-11.
Abstract: This article proposes an active fault isolation method for application to water distribution networks (WDNs) to localize leaks. The method relies on the classification of observed outputs to a discrete set of hypothetical faults. Due to parametric uncertainties, the outputs are random vectors that follow unknown probability distribution functions (PDFs). The output PDFs corresponding to the considered faults are approximated using smooth kernel density estimation (SKDE). They are used to calculate the posterior probability of each hypothesis, given the observed outputs, by applying Bayes’ rule. The difficulty to classify observed outputs to the right fault comes from the overlap between output PDFs. An active algorithm is introduced that proactively minimizes the joint overlap between the output PDFs by designing optimal control inputs. Due to physical limitations on control inputs and depending on the intensity of uncertainties, full separation, and hence fault isolation, cannot be guaranteed for a single observed output. Therefore, subsequent observations are used in an iterative framework, where the posterior probabilities of the previous time step serve as the prior probabilities for the next time step. The method is applied to locate leaks in a benchmark WDN for different levels of uncertainty in customer water demand and leakage magnitude. Improvements in the performance are observed in comparison to the best considered passive method from literature.
BibTeX:
@article{Lagen2022,
  author = {van Lagen, Gert and Abraham, Edo and Esfahani, Peyman Mohajerin},
  title = {A Bayesian Approach for Active Fault Isolation With an Application to Leakage Localization in Water Distribution Networks},
  journal = {IEEE Transactions on Control Systems Technology},
  year = {2022},
  pages = {1-11},
  url = {https://ieeexplore.ieee.org/document/9880532},
  doi = {10.1109/TCST.2022.3201334}
}
Khan Z, Abraham E, Aggarwal S, Ahmad Khan M, Arguello R, Babbar-Sebens M, Bereslawski JL, Bielicki JM, Campana PE, Silva Carrazzone ME and others (2022), "Emerging themes and future directions of multi-sector nexus research and implementation", Frontiers in Environmental Science. Vol. 10 Frontiers Media.
Abstract: Water, energy, and food are all essential components of human societies. Collectively, their respective resource systems are interconnected in what is called the “nexus”. There is growing consensus that a holistic understanding of the interdependencies and trade-offs between these sectors and other related systems is critical to solving many of the global challenges they present. While nexus research has grown exponentially since 2011, there is no unified, overarching approach, and the implementation of concepts remains hampered by the lack of clear case studies. Here, we present the results of a collaborative thought exercise involving 75 scientists and summarize them into 10 key recommendations covering: the most critical nexus issues of today, emerging themes, and where future efforts should be directed. We conclude that a nexus community of practice to promote open communication among researchers, to maintain and share standardized datasets, and to develop applied case studies will facilitate transparent comparisons of models and encourage the adoption of nexus approaches in practice.
BibTeX:
@article{Khan2022,
  author = {Khan, Zarrar and Abraham, Edo and Aggarwal, Srijan and Ahmad Khan, Manal and Arguello, Ricardo and Babbar-Sebens, Meghna and Bereslawski, Julia Lacal and Bielicki, Jeffrey M and Campana, Pietro Elia and Silva Carrazzone, Maria Eugenia and others},
  title = {Emerging themes and future directions of multi-sector nexus research and implementation},
  journal = {Frontiers in Environmental Science},
  publisher = {Frontiers Media},
  year = {2022},
  volume = {10},
  url = {https://www.frontiersin.org/articles/10.3389/fenvs.2022.918085/full},
  doi = {10.3389/fenvs.2022.918085}
}
van der Heijden T, Lugt D, van Nooijen R, Palensky P and Abraham E (2022), "Multi-market demand response from pump-controlled open canal systems: an economic MPC approach to pump-scheduling", Journal of Hydroinformatics., 06, 2022.
Abstract: Participation in demand response (DR) has been explored for many large energy-using assets based on day ahead electricity markets. In this manuscript, we propose the use of multiple electricity spot markets to enable price-based DR for open canal systems in the Netherlands, where many large pumping stations are used for flood mitigation and control of groundwater levels. In the new strategy for pump-scheduling, we combine the day ahead and intraday electricity markets to be used in a hierarchical receding horizon economic Model Predictive Control (MPC). We formulate the decision problem as a Mixed-Integer Quadratic Problem (MIQP), to be solved to near global optimality. A cost-potential analysis was performed for multiple market strategies and the automatic Frequency Restoration Reserves (aFRRs), using actual market and water system data. We show new insights into the trade-off between CO2 emissions and operating cost, the difference between the German and Dutch markets, and temporal changes in market conditions due to renewable energy integration. We observe that the German energy market is rewarding DR more than the Dutch equivalent, due to the higher renewable energy market penetration. The proposed multi-market strategy leads to a cost decrease of 10 and 16\% in the Netherlands in 2017 and 2019, respectively. When applying German market scenarios, we found a cost-saving potential of 56 and 50\% in 2017 and 2019, respectively. The cost-saving potential for the aFRR market was found to be up to 12\% in the Netherlands and 28\% in Germany, through a conservative analysis. The results suggest that the proposed control system, optimising costs over the day ahead, intraday and possibly the aFRR markets, is profitable compared to the current strategy in both the current and future electricity market.
BibTeX:
@article{10.2166/hydro.2022.018,
  author = {van der Heijden, Ties and Lugt, Dorien and van Nooijen, Ronald and Palensky, Peter and Abraham, Edo},
  title = {Multi-market demand response from pump-controlled open canal systems: an economic MPC approach to pump-scheduling},
  journal = {Journal of Hydroinformatics},
  year = {2022},
  note = {jh2022018},
  url = {https://doi.org/10.2166/hydro.2022.018},
  doi = {10.2166/hydro.2022.018}
}
Aydin BE, Oude Essink GH, Delsman JR, van de Giesen N and Abraham E (2022), "Nonlinear model predictive control of salinity and water level in polder networks: Case study of Lissertocht catchment", Agricultural Water Management. Vol. 264, pp. 107502.
Abstract: A significant increase in surface water salinization in low-lying deltas is expected globally due to saline groundwater exfiltration driven by rising sea levels and decreasing freshwater availability. Sustaining fresh water-dependent agriculture in such areas will entail an increased demand for fresh water flushing. Unfortunately, the flushing of surface water is not operationally optimised and results in excessive use of scarce freshwater. To meet the increased demand for flushing, while minimizing the need for diverted freshwater, new operational designs are required. This paper presents a novel network model based approach that uses De Saint Venant (SV) and Advection Dispersion (AD) equations to optimize multiple objectives on water level and salinity control using a Nonlinear Model Predictive Control (NMPC). The resulting NMPC problem is solved with a receding horizon implementation, where the nonlinear program (NLP) at each iteration is solved using state-of-the-art large scale interior point solver (IPOPT). We evaluate the performance of the proposed approach and compare it to the traditional fixed flushing for a representative Dutch polder. Firstly, the approach is shown to be capable of controlling the water level and salinity level in the polder. Secondly, the results highlight that the network of canals, which were originally made for drainage, could not be made sufficiently fresh with current intake capacity. A simple design approach was used to identify appropriate new capacities for two of the gates that allow optimal flushing to guarantee the required water level and salinity constraints.
BibTeX:
@article{AYDIN2022107502,
  author = {Boran Ekin Aydin and Gualbert H.P. Oude Essink and Joost R. Delsman and Nick van de Giesen and Edo Abraham},
  title = {Nonlinear model predictive control of salinity and water level in polder networks: Case study of Lissertocht catchment},
  journal = {Agricultural Water Management},
  year = {2022},
  volume = {264},
  pages = {107502},
  url = {https://www.sciencedirect.com/science/article/pii/S037837742200049X},
  doi = {10.1016/j.agwat.2022.107502}
}
Steffelbauer DB, Deuerlein J, Gilbert D, Abraham E and Piller O (2022), "Pressure-Leak Duality for Leak Detection and Localization in Water Distribution Systems", Journal of Water Resources Planning and Management. Vol. 148(3), pp. 04021106.
Abstract: Water utilities are challenged to reduce their water losses through detecting, localizing, and repairing leaks as quickly as possible in their aging distribution systems. In this work, we solve this challenging problem by detecting multiple leaks simultaneously in a water distribution network for the Battle of the Leak Detection and Isolation Methods. The performance of leak detection and localization depends on how well the system roughness and demand are calibrated. In addition, existing leaks affect the diagnosis performance unless they are identified and explicitly represented in the model. To circumvent this chicken-and-egg dilemma, we decompose the problem into multiple levels of decision-making (a hierarchical approach) where we iteratively improve the water distribution network model and so are able to solve the multileak diagnosis problem. First, a combination of time series and cluster analysis is used on smart meter data to build patterns for demand models. Second, point and interval estimates of pipe roughnesses are retrieved using least squares to calibrate the hydraulic model, utilizing the demand models from the first step. Finally, the calibrated primal model is transformed into a dual model that intrinsically combines sensor data and network hydraulics. This dual model automatically converts small pressure deviations caused by leaks into sharp and localized signals in the form of virtual leak flows. Analytical derivations of sensitivities with respect to these virtual leak flows are calculated and used to estimate the leakage impulse responses at candidate nodes. Subsequently, we use the dual network to (1)&nbsp;detect the start time of the leaks, and (2)&nbsp;compute the Pearson correlation of pressure residuals, which allows further localization of leaks. This novel dual modeling approach resulted in the highest true-positive rates for leak isolation among all participating teams in the competition.
BibTeX:
@article{dualleakmodel2022,
  author = {David B. Steffelbauer and Jochen Deuerlein and Denis Gilbert and Edo Abraham and Olivier Piller },
  title = {Pressure-Leak Duality for Leak Detection and Localization in Water Distribution Systems},
  journal = {Journal of Water Resources Planning and Management},
  year = {2022},
  volume = {148},
  number = {3},
  pages = {04021106},
  doi = {10.1061/(ASCE)WR.1943-5452.0001515}
}
Heijden TVD, Lago J, Palensky P and Abraham E (2021), "Electricity Price Forecasting in European Day Ahead Markets: A Greedy Consideration of Market Integration", IEEE Access., Septermber, 2021. Vol. 9, pp. 119954-119966.
Abstract: In this manuscript we explore European feature importance in Day Ahead Market (DAM) price forecasting models, and show that model performance can deteriorate when too many features are included due to over-fitting. We propose a greedy algorithm to search over candidate countries for European features to be used in a DAM price forecasting model, that can be applied to several regression and machine learning modelling methodologies. We apply the algorithm to build price forecasting models for the Dutch market, using candidate countries selected through an integrated analysis based on open-source European electricity market data. Feature importance is visualised using an Auto Regressive and Random Forest model. We explain these results using cross-border flow and DAM price data. Two types of models (LEAR and the Deep Neural Network) are considered for the DAM price forecasting with and without European features. We show that in the Dutch case, taking European market integration into account improves the Mean Absolute Error (MAE) of the best performing DAM price forecasting model by 3.1%, the relative MAE (rMAE) by 3.85%, and the Symmetrical Mean Absolute Percentage Error (sMAPE) by 0.31 p.p., compared to the best forecasting model without European features. Through statistical testing we show that European features improve the accuracy of the forecasts with statistical significance.
BibTeX:
@article{9524683,
  author = {Heijden, Ties Van Der and Lago, Jesus and Palensky, Peter and Abraham, Edo},
  title = {Electricity Price Forecasting in European Day Ahead Markets: A Greedy Consideration of Market Integration},
  journal = {IEEE Access},
  year = {2021},
  volume = {9},
  pages = {119954-119966},
  doi = {10.1109/ACCESS.2021.3108629}
}
Verhagen J, van der Zaag P and Abraham E (2021), "Operational planning of WEF infrastructure: quantifying the value of information sharing and cooperation in the Eastern Nile basin", Environmental Research Letters., jul, 2021. Vol. 16(8), pp. 085006. IOP Publishing.
Abstract: Integrating the planning of a multi-reservoir system in nexus with agricultural and electricity infrastructure could alleviate security concerns for these resources in regions where demand is growing while water and land scarcity are exacerbated by climate change and anthropogenic pressures. This study focuses on the benefits of resource integration and cooperation in the Eastern Nile basin. To overcome common limitations of equilibrium and soft-linked partial equilibrium models (e.g. high levels of spatial aggregation, non-insightful cooperation scenarios and a lack of heterogeneity), we propose a regional hard-linked WEF-nexus model that explicitly represents resource connectivity networks for water and electricity, and describes heterogeneity in resource availability, production potentials and physical constraints. Using a non-linear operational process, we optimise reservoir operations, water allocations, cropping patterns, electricity mixes and trade quantities on a monthly time-step over multiple years in a receding horizon fashion to maximize economic benefits for each country and regionally. This iterative implementation allows the modelling of operational changes as feedback against exogenous climate disturbances and enables information exchange between upstream-downstream countries. Thus, we describe four different levels of transboundary cooperation with their corresponding constraints and policy objectives. Compared to the reference scenario of unilateral planning, our results indicate an increase in regional economic returns for scenarios in which river flow information is shared between countries (+9, river flow and trade information are shared (+10 and WEF resources are coordinated regionally (+15. These increased returns successively come from an increase in the effectiveness of agricultural water consumption, especially in Sudan, a change in trade patterns for agricultural products and a shift in cropping patterns. These findings underscore the importance of adequate representations of spatial and temporal heterogeneity of resources and their connectivity, as well as the need for a more diverse set of collaboration scenarios to facilitate planning in transboundary river systems.
BibTeX:
@article{wefNile2021planning,
  author = {Jeroen Verhagen and Pieter van der Zaag and Edo Abraham},
  title = {Operational planning of WEF infrastructure: quantifying the value of information sharing and cooperation in the Eastern Nile basin},
  journal = {Environmental Research Letters},
  publisher = {IOP Publishing},
  year = {2021},
  volume = {16},
  number = {8},
  pages = {085006},
  url = {https://doi.org/10.1088/1748-9326/ac1194},
  doi = {10.1088/1748-9326/ac1194}
}
Kaandorp C, van de Giesen N and Abraham E (2021), "The water use of heating pathways to 2050: analysis of national and urban energy scenarios", Environmental Research Letters., may, 2021. Vol. 16(5), pp. 055031. IOP Publishing.
Abstract: Sustainable energy systems can only be achieved when reducing both carbon emissions and water use for energy generation. Although the water use for electricity generation has been well studied, integrated assessments of the water use by low-carbon heat systems are lacking. In this paper we present an analysis of the water use of scenarios for heat and electricity production for the year 2050 for the Netherlands and its capital, Amsterdam. The analysis shows that (i) the water withdrawal for heating can increase up to the same order of magnitude as the current water withdrawal of thermoelectric plants due to the use of aquifer thermal energy storage, (ii) the virtual water use for heating can become higher than the operational water consumption for heating, and (iii) the water use for electricity production becomes a relevant indicator for the virtual water use for heat generation because of the increase of power-to-heat applications.
BibTeX:
@article{heatingTrasition2021b,
  author = {C Kaandorp and N van de Giesen and E Abraham},
  title = {The water use of heating pathways to 2050: analysis of national and urban energy scenarios},
  journal = {Environmental Research Letters},
  publisher = {IOP Publishing},
  year = {2021},
  volume = {16},
  number = {5},
  pages = {055031},
  url = {https://doi.org/10.1088/1748-9326/abede7},
  doi = {10.1088/1748-9326/abede7}
}
Abraham E, Verbart J and van der Hoek J (2020), "Smart solutions for intermittent supply systems", The Source -- The magazine of the International Water Association., December, 2020. Vol. 21, pp. 24-28.
Abstract: Intermittent operation of water supply networks is widespread, including in sub-Saharan Africa. Edo Abraham, Joost Verbart and Jan Peter van der Hoek look at the opportunities to use digital technologies to improve management.
BibTeX:
@article{abrahamsmartintermittent2020,
  author = {E. Abraham and J.J.G.M. Verbart and van der Hoek, J.P.},
  title = {Smart solutions for intermittent supply systems},
  journal = {The Source -- The magazine of the International Water Association},
  year = {2020},
  volume = {21},
  pages = {24--28},
  note = {Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ -- Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.},
  url = {https://www.thesourcemagazine.org/smart-solutions-for-intermittent-supply-systems/}
}
Steffelbaeur D, Blokker M, Buchberger S, Knobe A and Abraham E (2021), "Dynamic Time Warping Clustering to Discover Socioeconomic Characteristics in Smart Water Meter Data", Journal of Water Resources Planning and Management. Vol. 147(6), pp. 04021026.
Abstract: Socioeconomic characteristics are influencing the temporal and spatial variability of water demand, which are the biggest source of uncertainties within water distribution system modeling. Improving current knowledge of these influences can be utilized to decrease demand uncertainties. This paper aims to link smart water meter data to socioeconomic user characteristics by applying a novel clustering algorithm that uses a dynamic time warping metric on daily demand patterns. The approach is tested on simulated and measured single-family home data sets. It is shown that the novel algorithm performs better compared with commonly used clustering methods, both in finding the right number of clusters as well as assigning patterns correctly. Additionally, the methodology can be used to identify outliers within clusters of demand patterns. Furthermore, this study investigates which socioeconomic characteristics (e.g.,&nbsp;employment status and number of residents) are prevalent within single clusters and, consequently, can be linked to the shape of the cluster's barycenters. In future, the proposed methods in combination with stochastic demand models can be used to fill data gaps in hydraulic models.
BibTeX:
@article{DTWSmartMeterData2021,
  author = {David Steffelbaeur and Mirjam Blokker and Steven Buchberger and Arno Knobe and Edo Abraham},
  title = {Dynamic Time Warping Clustering to Discover Socioeconomic Characteristics in Smart Water Meter Data},
  journal = {Journal of Water Resources Planning and Management},
  year = {2021},
  volume = {147},
  number = {6},
  pages = {04021026},
  url = {https://doi.org/10.1061/(ASCE)WR.1943-5452.0001360},
  doi = {10.1061/(ASCE)WR.1943-5452.0001360}
}
Burger R and Abraham E (2020), "Maximizing Water--Food--Energy Nexus Synergies at Basin Scale", In Frontiers in Water-Energy-Nexus: Nature-Based Solutions, Advanced Technologies and Best Practices for Environmental Sustainability. , pp. 67-70. Springer.
BibTeX:
@incollection{Burger2020,
  author = {Rogier Burger and Edo Abraham},
  editor = {Naddeo V. and Balakrishnan M. and Choo KH.},
  title = {Maximizing Water--Food--Energy Nexus Synergies at Basin Scale},
  booktitle = {Frontiers in Water-Energy-Nexus: Nature-Based Solutions, Advanced Technologies and Best Practices for Environmental Sustainability},
  publisher = {Springer},
  year = {2020},
  pages = {67--70},
  url = {https://link.springer.com/chapter/10.1007/978-3-030-13068-8_16}
}
Chang N-B, Hossain U, Valencia A, Qiu J, Zheng QP, Gu L, Chen M, Lu J-W, Pires A, Kaandorp C, Abraham E, ten Veldhuis M-C, van de Giesen N, Molle B, Tomas S, Ait-Mouheb N, Dotta D, Declercq R, Perrin M, Conradi L and Molle G (2020), "Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (I): Global trend and technology metrics", Critical Reviews in Environmental Science and Technology. Vol. 0(0), pp. 1-46. Taylor & Francis.
BibTeX:
@article{doi:10.1080/10643389.2020.1759328,
  author = {Ni-Bin Chang and Uzzal Hossain and Andrea Valencia and Jiangxiao Qiu and Qipeng P. Zheng and Lixing Gu and Mengnan Chen and Jia-Wei Lu and Ana Pires and Chelsea Kaandorp and Edo Abraham and Marie-Claire ten Veldhuis and Nick van de Giesen and Bruno Molle and Severine Tomas and Nassim Ait-Mouheb and Deborah Dotta and Rémi Declercq and Martin Perrin and Léon Conradi and Geoffrey Molle},
  title = {Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (I): Global trend and technology metrics},
  journal = {Critical Reviews in Environmental Science and Technology},
  publisher = {Taylor & Francis},
  year = {2020},
  volume = {0},
  number = {0},
  pages = {1-46},
  url = {https://doi.org/10.1080/10643389.2020.1759328},
  doi = {10.1080/10643389.2020.1759328}
}
Chang N-B, Hossain U, Valencia A, Qiu J, Zheng QP, Gu L, Chen M, Lu J-W, Pires A, Kaandorp C, Abraham E, ten Veldhuis M-C, van de Giesen N, Molle B, Tomas S, Ait-Mouheb N, Dotta D, Declercq R, Perrin M, Conradi L and Molle G (2020), "Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (II): Design strategies for urban sustainability", Critical Reviews in Environmental Science and Technology. Vol. 0(0), pp. 1-51. Taylor & Francis.
Abstract: AbstractThe Food-Energy-Water (FEW) nexus for urban sustainability needs to be analyzed via an integrative rather than a sectoral or silo approach, reflecting the ongoing transition from separate infrastructure systems to an integrated social-ecological-infrastructure system. As technology hubs can provide food, energy, water resources via decentralized and/or centralized facilities, there is an acute need to optimize FEW infrastructures by considering cost-benefit-risk tradeoffs with respect to multiple sustainability indicators. This paper identifies, categorizes, and analyzes global trends with respect to contemporary FEW technology metrics that highlights the possible optimal integration of a broad spectrum of technology hubs for possible cost-benefit-risk tradeoffs. The challenges related to multiscale and multiagent modeling processes for the simulation of urban FEW systems were discussed with respect to the aspects of scaling-up, optimization process, and risk assessment. Our review reveals that this field is growing at a rapid pace and the previous selection of analytical methodologies, nexus criteria, and sustainability indicators largely depended on individual FEW nexus conditions disparately, and full-scale cost-benefit-risk tradeoffs were very rare. Therefore, the potential full-scale technology integration in three ongoing cases of urban FEW systems in Miami (the United States), Marseille (France), and Amsterdam (the Netherlands) were demonstrated in due purpose finally.
BibTeX:
@article{doi:10.1080/10643389.2020.1761088,
  author = {Ni-Bin Chang and Uzzal Hossain and Andrea Valencia and Jiangxiao Qiu and Qipeng P. Zheng and Lixing Gu and Mengnan Chen and Jia-Wei Lu and Ana Pires and Chelsea Kaandorp and Edo Abraham and Marie-Claire ten Veldhuis and Nick van de Giesen and Bruno Molle and Severine Tomas and Nassim Ait-Mouheb and Deborah Dotta and Rémi Declercq and Martin Perrin and Léon Conradi and Geoffrey Molle},
  title = {Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (II): Design strategies for urban sustainability},
  journal = {Critical Reviews in Environmental Science and Technology},
  publisher = {Taylor & Francis},
  year = {2020},
  volume = {0},
  number = {0},
  pages = {1-51},
  url = {https://doi.org/10.1080/10643389.2020.1761088},
  doi = {10.1080/10643389.2020.1761088}
}
Farrokhzadeh S, Hashemi Monfared SA, Azizian G, Sardar Shahraki A, Ertsen MW and Abraham E (2020), "Sustainable Water Resources Management in an Arid Area Using a Coupled Optimization-Simulation Modeling", Water. Vol. 12(3), pp. 885. Multidisciplinary Digital Publishing Institute.
BibTeX:
@article{farrokhzadeh2020sustainable,
  author = {Farrokhzadeh, Siamak and Hashemi Monfared, Seyed Arman and Azizian, Gholamreza and Sardar Shahraki, Ali and Ertsen, Maurits W and Abraham, Edo},
  title = {Sustainable Water Resources Management in an Arid Area Using a Coupled Optimization-Simulation Modeling},
  journal = {Water},
  publisher = {Multidisciplinary Digital Publishing Institute},
  year = {2020},
  volume = {12},
  number = {3},
  pages = {885},
  url = {https://www.mdpi.com/2073-4441/12/3/885},
  doi = {10.3390/w12030885}
}
Kassing R, de Schutter B and Abraham E (2020), "Optimal Control for Precision Irrigation of a Large-Scale Plantation: Closed-loop analysis with AquaCrop-OS", Water Resources Research, AGU. Vol. e2019WR026989
BibTeX:
@article{Kassing2020wrr,
  author = {Ruud Kassing and Bart de Schutter and Edo Abraham},
  title = {Optimal Control for Precision Irrigation of a Large-Scale Plantation: Closed-loop analysis with AquaCrop-OS},
  journal = {Water Resources Research, AGU},
  year = {2020},
  volume = {e2019WR026989},
  url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019WR026989},
  doi = {10.1029/2019WR026989}
}
Kassing R, de Schutter B and Abraham E (2020), "Optimal seasonal water allocation and model predictive control for precision irrigation", In EGU General Assembly Conference Abstracts., 12, 2020.
BibTeX:
@conference{KassingetalEGU2020,
  author = {Ruud Kassing and Bart de Schutter and Edo Abraham},
  title = {Optimal seasonal water allocation and model predictive control for precision irrigation},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-11270.html}
}
Khan Z, Abraham E and Byers E (2020), "Multi-scale water-energy-land nexus planning to manage socio-economic, climatic, and technological change", In EGU 2020 Scientific Sessions, Convened Session.
Abstract: The world's energy, water, and land systems are in transition and rapidly integrating, driven by forces such as socioeconomic, demographic, climatic, and technological changes as well as policies intended to meet Sustainable Development Goals (SDGs) and other societal priorities. These dynamics weave across spatial scales, connecting global markets and trends to regional and sub-regional economies. At the same time, resources are often locally managed under varying administrative jurisdictions closely tied to inherent characteristics of each commodity such as river basins for water, grid regions for electricity and land-use boundaries for agriculture. Local decisions in turn are critical in deciding the aggregate success and consequences of national and global policies. Thus, there is a growing need to better characterize the energy-water-land nexus to guide robust and consistent decision making across these scales. This session invites abstracts exploring energy-water-land dynamics, trade patterns, policy interventions, infrastructure planning and uncertainty characterization across variable spatial boundaries.

Keys: Integrated Assessment Modelling, Water-Energy-Food Nexus, Infrastructure Decisions, Urbanization, Climate Change</td> </tr>

BibTeX:
@inproceedings{KhanAbrahamByers2020,
  author = {Zarrar Khan and Edo Abraham and Edward Byers},
  title = {Multi-scale water-energy-land nexus planning to manage socio-economic, climatic, and technological change},
  booktitle = {EGU 2020 Scientific Sessions, Convened Session},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/session/35928}
}
Paez. DA, Filion Y, ..., Deuerlein J, Gilbert D, Abraham E, Piller O, ..., Savic D and Walski T (2020), "The Battle of Post-Disaster Response and Restoration (BPDRR)", Journal of Water Resources Planning and Management.
BibTeX:
@article{Paezeatal2020,
  author = {Diego Alejandro Paez.; Yves Filion; ... ;Jochen Deuerlein; Denis Gilbert; Edo Abraham ; Olivier Piller; ... ; Dragan Savic; Thomas Walski},
  title = {The Battle of Post-Disaster Response and Restoration (BPDRR)},
  journal = {Journal of Water Resources Planning and Management},
  year = {2020},
  note = {Accepted}
}
Sakomoto T, Lutaaya M and Abraham E (2020), "Managing Water Quality in Intermittent Supply Systems: The Case of Mukono Town, Uganda", Water. Vol. 12(3), pp. 806. Multidisciplinary Digital Publishing Institute.
BibTeX:
@article{sakomoto2020managing,
  author = {Sakomoto, Takuya and Lutaaya, Mahmood and Abraham, Edo},
  title = {Managing Water Quality in Intermittent Supply Systems: The Case of Mukono Town, Uganda},
  journal = {Water},
  publisher = {Multidisciplinary Digital Publishing Institute},
  year = {2020},
  volume = {12},
  number = {3},
  pages = {806},
  doi = {10.3390/w12030806}
}
van Steen J, Steffelbauer D, Balkema S, van der Hoek JP and Abraham E (2020), "Fantastic leaks and where to find them", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{Steen2020,
  author = {Jip van Steen and David Steffelbauer and Sijbrand Balkema and Jan Peter van der Hoek and Edo Abraham},
  title = {Fantastic leaks and where to find them},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-8305.html}
}
Steffelbauer D, Blokker M, Knobbe A and Abraham E (2020), "DASH of Water -- water distribution system modelling in the age of smart water meters", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{SteffelbaueretalEGU2020,
  author = {David Steffelbauer and Mirjam Blokker and Arno Knobbe and Edo Abraham},
  title = {DASH of Water -- water distribution system modelling in the age of smart water meters},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-13439.html}
}
Aydin B, Tian X, Delsman J, Oude Essink GualbertHP, Rutten M and Abraham E (2019), "Optimal salinity and water level control of water courses using Model Predictive Control", Environmental Modelling & Software., 2, 2019. Vol. 112, pp. 36-45. Elsevier.
Abstract: Worldwide, delta areas are under stress due to climate change. With rising sealevels and decreasing freshwater availability, surface water salinization due togroundwater exfiltration is expected to increase in these low-lying areas. Tocounteract surface water salinization, freshwater diverted from rivers is used to flush agricultural ditches. In this paper, we demonstrate a Model Predictive Control (MPC) scheme to control salinity and water levels in a water course while minimizing freshwater usage. A state space description of the discretized De Saint Venant and advection-dispersion equations for water and salt transport, respectively, is used as the internal model of the controller. The developed MPC scheme is tested using groundwater exfiltration data from two different representative Dutch polders. The tests demonstrate that water levels and salinity concentrations can successfully be controlled within set limits while minimizing the freshwater used.
BibTeX:
@article{0a25d27b09884d21830f6b76e07277b1,
  author = {Boran Aydin and Xin Tian and Joost Delsman and Oude Essink, Gualbert H.P. and Martine Rutten and Edo Abraham},
  title = {Optimal salinity and water level control of water courses using Model Predictive Control},
  journal = {Environmental Modelling & Software},
  publisher = {Elsevier},
  year = {2019},
  volume = {112},
  pages = {36--45},
  doi = {10.1016/j.envsoft.2018.11.010}
}
Odriozola M, Abraham E, Lousada-Ferreira M, Spanjers H and van Lier JulesB (2019), "Identification of the methanogenesis inhibition mechanism using comparative analysis of mathematical models", Frontiers in Bioengineering and Biotechnology. Vol. 7
Abstract: The application of cationic polymers to enhance membrane fluxes in anaerobic membrane bioreactors has been proposed by several authors. However, literature shows contradictory results on the influence of those chemicals on the biological activity. In this research, we studied the effect of a cationic polymer on the production of methane from acetate by acetoclastic methanogens. We assessed the effect of polymer concentration on the accumulated methane production (AMP) and the specific methanogenic activity (SMA) in batch tests. Batch tests results showed lower SMA values at higher concentrations of polymer and no effect on the final AMP. Different inhibition models were calibrated and compared to find the best fit and to hypothesize the prevailing inhibition mechanisms. The assessed inhibition models were: competitive (M1a), non-competitive (M2a), un-competitive (M3a), biocide-linear (M4a), and biocide-exponential (M5a). The parameters in the model related to the polymer characteristics were adjusted to fit the experimental data. M2a and M3a were the only models that fitted both experimental SMA and AMP. Although M1a and M4a adequately fitted the experimental SMA, M1a simulations slightly deviated from the experimental AMP, and M4a considerably underpredicted the AMP at concentrations of polymer above 0.23 gCOD L-1. M5a did not adequately fit either experimental SMA and AMP results. We compared models a (M1a to M5a), which consider the inhibition by the concentration of polymer in the bulk liquid, with models b (M1b to M5b) considering the inhibition being caused by the total concentration of polymer in the reactor. Results showed that the difference between a and b models' simulations were negligible for all kinetic models considered (M1, M2, M3, M4, and M5). Therefore, the models that better predicted the experimental data were the non-competitive (M2a and M2b) and un-competitive (M3a and M3b) inhibition models, which are biostatic inhibition models. Consequently, the decreased methanogenic activity caused by polymer additions is presumably a reversible process.
BibTeX:
@article{6ee0fab4e8ec493aa97749f9bc266443,
  author = {Magela Odriozola and Edo Abraham and Maria Lousada-Ferreira and Henri Spanjers and van Lier, Jules B.},
  title = {Identification of the methanogenesis inhibition mechanism using comparative analysis of mathematical models},
  journal = {Frontiers in Bioengineering and Biotechnology},
  year = {2019},
  volume = {7},
  doi = {10.3389/fbioe.2019.00093}
}
Abraham E, Pecci F and Stoianov I (2019), "A multi-objective framework for managing self-cleaning capacity and leakage: application to a real network model,", In Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI). Exeter, UK, Septermber, 2019.
BibTeX:
@inproceedings{Abraham2019,
  author = {Edo Abraham and Filippo Pecci and Ivan Stoianov},
  title = {A multi-objective framework for managing self-cleaning capacity and leakage: application to a real network model,},
  booktitle = {Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  year = {2019}
}
Abraham E, Khan Z and Pande S (2019), "Integrated Assessment of water -- food -- energy nexuses", In EGU 2019 Scientific Sessions, Convened Session.
Abstract: Developing a sustainable future requires the optimal integration and synergising of energy, agriculture and water sectors. As developing economies grow with rapid urbanisation, access to modern energy and water services should grow sustainably. Quantitative tools for planning and assessing national and basin scale infrastructure planning are essential for this. Issues of access and the challenges of biophysical and socioeconomic dynamics involved therein are often poorly reflected in plans. Integrated Assessment Modeling (IAMs) can allow for studying interactions between the economy, water use, energy use, and the environment. IAMs enable investigating long-term transition pathways in the context of climate change and shared socioeconomic pathways.

Most IAMs, however, are mainly global and at best regional, and as such do not adequately represent socio-hydrological mechanisms at smaller scale. On the other hand, basin scale studies often poorly reflect national and regional drivers. One of the main bottlenecks is the intrinsic difficulty in bridging the high-level system-oriented approach of IAMs with the strong dependency of the efficacy of plans on local socioeconomic and hydrological drivers. We invite contributions connecting fundamental and applied research for policy making, concepts and case studies to better understand how IAMs can be better utilised in infrastructure decisions at regional, country or basin scales.

Keys: Integrated Assessment Modelling, Water-Energy-Food Nexus, Infrastructure Decisions, Urbanization, Climate Change</td> </tr>

BibTeX:
@inproceedings{abrahamKhanEGU2019,
  author = {Edo Abraham and Zarrar Khan and Saket Pande},
  title = {Integrated Assessment of water -- food -- energy nexuses},
  booktitle = {EGU 2019 Scientific Sessions, Convened Session},
  year = {2019},
  note = {Convened Session},
  url = {https://meetingorganizer.copernicus.org/EGU2019/session/30354}
}
Aydin BE, Hagedooren H and Abraham E (2019), "A Heuristic Approach to Effective Sensor Placement for Salinity State Reconstruction in a Low-Lying Polder", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{Aydin2019,
  author = {Aydin, Boran Ekin and Hagedooren, Hugo and Abraham, Edo},
  title = {A Heuristic Approach to Effective Sensor Placement for Salinity State Reconstruction in a Low-Lying Polder},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2019}
}
Aydin BoranEkin, Hagedooren H, Rutten MartineM, Delsman J, Essink GualbertHPOude, van de Giesen N and Abraham E (2019), "A greedy algorithm for optimal sensor placement to estimate salinity in polder networks", Water. Vol. 11(5) Multidisciplinary Digital Publishing Institute (MDPI).
BibTeX:
@article{Aydin2019a,
  author = {Aydin, Boran Ekin and Hugo Hagedooren and Rutten, Martine M. and Joost Delsman and Essink, Gualbert H.P.Oude and van de Giesen, Nick and Edo Abraham},
  title = {A greedy algorithm for optimal sensor placement to estimate salinity in polder networks},
  journal = {Water},
  publisher = {Multidisciplinary Digital Publishing Institute (MDPI)},
  year = {2019},
  volume = {11},
  number = {5},
  doi = {10.3390/w11051101}
}
Pecci F, Abraham E and Stoianov I (2019), "Model Reduction and Outer Approximation for Optimizing the Placement of Control Valves in Complex Water Networks", Journal of Water Resources Planning and Management. Vol. 145(5) American Society of Civil Engineers (ASCE).
Abstract: The optimal placement and operation of pressure control valves in water distribution networks is a challenging engineering problem. When formulated in a mathematical optimization framework, this problem results in a nonconvex mixed integer nonlinear program (MINLP), which has combinatorial computational complexity. As a result, the considered MINLP becomes particularly difficult to solve for large-scale looped operational networks. We extend and combine network model reduction techniques with the proposed optimization framework in order to lower the computational burden and enable the optimal placement and operation of control valves in these complex water distribution networks. An outer approximation algorithm is used to solve the considered MINLPs on reduced hydraulic models. We demonstrate that the restriction of the considered optimization problem on a reduced hydraulic model is not equivalent to solving the original larger MINLP, and its solution is therefore sub-optimal. Consequently, we investigate the trade-off between reducing computational complexity and the potential sub-optimality of the solutions that can be controlled with a parameter of the model reduction routine. The efficacy of the proposed method is evaluated using two large scale water distribution network models.
BibTeX:
@article{db80276b5de9451ba60787d414f19d66,
  author = {Filippo Pecci and Edo Abraham and Ivan Stoianov},
  title = {Model Reduction and Outer Approximation for Optimizing the Placement of Control Valves in Complex Water Networks},
  journal = {Journal of Water Resources Planning and Management},
  publisher = {American Society of Civil Engineers (ASCE)},
  year = {2019},
  volume = {145},
  number = {5},
  note = {Accepted Author Manuscript},
  doi = {10.1061/(ASCE)WR.1943-5452.0001055}
}
Farrokhzadeh S, Abraham E and Ertsen M (2019), "A Multi-Objective Approach for the Analysis of a Water-Food-Ecosystems Nexus at Basin Scale", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{Farrokhzadeh2019,
  author = {Farrokhzadeh, Siamak and Abraham, Edo and Ertsen, Maurits},
  title = {A Multi-Objective Approach for the Analysis of a Water-Food-Ecosystems Nexus at Basin Scale},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2019},
  url = {https://www.egu2019.eu/}
}
van der Heijden T, Lugt D, van Nooyen R, Palensky P and Abraham E (2019), "Demand response from pumping infrastructure in the Dutch Delta", In International Conference on Applied Energy., August, 2019.
BibTeX:
@inproceedings{Heijden2019a,
  author = {T.J.T. van der Heijden and D. Lugt and R.R.P. van Nooyen and P. Palensky and E. Abraham},
  title = {Demand response from pumping infrastructure in the Dutch Delta},
  booktitle = {International Conference on Applied Energy},
  year = {2019}
}
van der Heijden T, Klopstra D and Abraham E (2019), "Optimising water system operations, blue storage and the green energy transition", TU Delft DeltaLinks.
Kaandorp C, van de Giesen N and Abraham E (2019), "Water security: threats and opportunities of a heat transition", LIRS symposium 2019. Heerlen, Netherlands
BibTeX:
@conference{Kaandorp2019,
  author = {Kaandorp, Chelsea and van de Giesen, Nick and Edo Abraham},
  title = {Water security: threats and opportunities of a heat transition},
  journal = {LIRS symposium 2019},
  year = {2019}
}
Kaandorp C, van de Giesen N and Abraham E (2019), "Spatio-temporal modelling of urban water flows related to the integration of energy technologies in Amsterdam, the Netherlands.", EGU General Assembly 2019., In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{Kaandorp2019a,
  author = {Kaandorp, Chelsea and van de Giesen, Nick and Edo Abraham},
  title = {Spatio-temporal modelling of urban water flows related to the integration of energy technologies in Amsterdam, the Netherlands.},
  booktitle = {EGU General Assembly Conference Abstracts},
  journal = {EGU General Assembly 2019},
  year = {2019}
}
LageLand G, Abraham E and Esfahani P (2019), "Active Leak Localisation in a Water Distribution Network through pressure driven models and bayesian classification", IEEE Transactions on Control Systems Technology. Vol. Working Paper
BibTeX:
@article{LageLand2019,
  author = {Gert LageLand and Edo Abraham and PeymanMohajerin Esfahani},
  title = {Active Leak Localisation in a Water Distribution Network through pressure driven models and bayesian classification},
  journal = {IEEE Transactions on Control Systems Technology},
  year = {2019},
  volume = {Working Paper}
}
Pecci F, Abraham E and Stoianov I (2019), "Tight convex relaxations for optimal design and control problems in water supply networks", In Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI). Exeter, UK, Septermber, 2019.
BibTeX:
@inproceedings{Pecci2019,
  author = {Filippo Pecci and Edo Abraham and Ivan Stoianov},
  title = {Tight convex relaxations for optimal design and control problems in water supply networks},
  booktitle = {Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  year = {2019}
}
Pecci F, Abraham E and Stoianov I (2019), "Global optimality bounds for the placement of control valves in water supply networks", Optimization and Engineering. Vol. 20(2), pp. 457-495. Springer.
Abstract: In this article, a comprehensive review of existing methods is presented and computationally efficient sparse null space algorithms are proposed for the hydraulic analysis of water distribution networks. The linear systems at each iteration of the Newton method for nonlinear equations are solved using a null space algorithm. The sparsity structure of these linear equations, which arises from the sparse network connectivity, is exploited to reduce computations. A significant fraction of the total flops in the Newton method are spent in computing pipe head losses and matrix-matrix multiplications involving flows. Because most flows converge after a few iterations, a novel partial update of head losses and matrix products is used to further reduce computational complexity. Convergence analyses are also presented for the partialupdate formulas. A new heuristic for reducing the number of pressure head computations of a null space method is proposed. These savings enable fast near-real-time control of large-scale water networks. It is often observed that the linear equations that arise in solving the hydraulic equations become ill-conditioned due to hydraulic solutions with very small and zero flows. The condition numbers of the Newton equations are bounded using a regularization technique with insignificant computational overheads. The convergence properties of all proposed algorithms are analyzed by posing them as an inexact-Newton method. Small-scale to large-scale models of operational water networks are used to evaluate the proposed algorithms.
BibTeX:
@article{pecci2019global,
  author = {Pecci, Filippo and Abraham, Edo and Stoianov, Ivan},
  title = {Global optimality bounds for the placement of control valves in water supply networks},
  journal = {Optimization and Engineering},
  publisher = {Springer},
  year = {2019},
  volume = {20},
  number = {2},
  pages = {457--495},
  doi = {10.1007/s11081-018-9412-7}
}
Sakomoto T, Lutaaya M and Abraham E (2019), "Managing water quality in intermittent supply systems: the case of Mukono Town, Uganda", In Proceedings of IWA-ASPIRE Conference., November, 2019.
BibTeX:
@inproceedings{Sakomoto2019,
  author = {Takuya Sakomoto and Mahmood Lutaaya and Edo Abraham},
  title = {Managing water quality in intermittent supply systems: the case of Mukono Town, Uganda},
  booktitle = {Proceedings of IWA-ASPIRE Conference},
  year = {2019}
}
Steffelbauer D, Blokker M, Knobbe A and Abraham E (2019), "Stochastic drinking water demand model parameterisation with smart meter data and data science algorithms", In Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI). Exeter, UK, Septermber, 2019.
BibTeX:
@inproceedings{Steffelbauer2019,
  author = {David Steffelbauer and Mirjam Blokker and Arno Knobbe and Edo Abraham},
  title = {Stochastic drinking water demand model parameterisation with smart meter data and data science algorithms},
  booktitle = {Proc. 17th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  year = {2019}
}
van der Heijden T, Lugt D, van Nooyen R, Palensky P and Abraham E (2019), "Energy markets and sustainable water management: pumping and demand response in the Dutch delta.", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{T2019,
  author = {T.J.T. van der Heijden and D. Lugt and R.R.P. van Nooyen and P. Palensky and E. Abraham},
  title = {Energy markets and sustainable water management: pumping and demand response in the Dutch delta.},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2019}
}
Authors: Yacob Mulugetta (UCL), Pablo E. Carvajal (IRENA), James Haselip (UNEP DTU), Thomas Spencer (TERI) and Contributing authors: Edo Abraham (TU Delft), Simon Batchelor (Gamos Ltd), Brigitte Knopf (Mercator) (2019), "Bridging the Gap: Global Transformation of the Energy System", In Bridging the Gap -- Enhancing Mitigation Ambition and Action at G20 Level and Globally. United Nations Environment Programme.
BibTeX:
@techreport{UCL2019,
  author = {Authors: Yacob Mulugetta (UCL), Pablo E. Carvajal (IRENA), James Haselip (UNEP DTU), Thomas Spencer (TERI) and Contributing authors: Edo Abraham (TU Delft), Simon Batchelor (Gamos Ltd), Brigitte Knopf (Mercator) },
  editor = {Höhne, N and Fransen, T and Hans, F and Bhardwaj, A and Blanco, G and den Elzen, M and Hagemann, M and Henderson, C and Keesler, D and Kejun, J and others},
  title = {Bridging the Gap: Global Transformation of the Energy System},
  booktitle = {Bridging the Gap -- Enhancing Mitigation Ambition and Action at G20 Level and Globally},
  publisher = {United Nations Environment Programme},
  year = {2019},
  url = {https://wedocs.unep.org/bitstream/handle/20.500.11822/30797/EGR2019.pdf?sequence=1&isAllowed=y}
}
Abraham E, Blokker E and Stoianov I (2018), "Decreasing the Discolouration Risk of Drinking Water Distribution Systems through Optimised Topological Changes and Optimal Flow Velocity Control", Journal of Water Resources Planning and Management., 2, 2018. Vol. 144(10) American Society of Civil Engineers (ASCE).
Abstract: In this paper, a new mathematical framework is proposed for maximizing the self-cleaning capacity (SCC) of drinking water distribution systems by controlling the diurnal peak flow velocities in the pipes under normal operation. This is achieved through an optimal change of the network connectivity (topology). This paper proposes an efficient algorithm for the network analysis of valve closures, which allows enforcing favorable changes in the flow velocities for maximizing the SCC by determining an optimal set of links to isolate in the forming of a more branched network, while concurrently satisfying the hydraulic and regulatory pressure constraints at the demand nodes. Multiple stochastic demands from an end-use demand model are generated to test the robustness in the improved SCC for the modified network connectivity under changing demand. An operational network model is used to demonstrate the efficacy of the proposed approach.
BibTeX:
@article{40f6e7dfec4240a980dccc4735caaaaa,
  author = {Edo Abraham and EJM Blokker and Ivan Stoianov},
  title = {Decreasing the Discolouration Risk of Drinking Water Distribution Systems through Optimised Topological Changes and Optimal Flow Velocity Control},
  journal = {Journal of Water Resources Planning and Management},
  publisher = {American Society of Civil Engineers (ASCE)},
  year = {2018},
  volume = {144},
  number = {10},
  doi = {10.1061/(ASCE)WR.1943-5452.0000878}
}
Aydin B, Rutten M and Abraham E (2018), "Model Predictive Control of Salinity and Water Level in a Hypothetical Polder Ditch: Is it Possible to Use the Discretized Linearized Physical Equations for Optimization", In EPiC Series in Engineering., 9, 2018. Vol. 3, pp. 117-122. EasyChair.
Abstract: Surface water salinization in deltaic areas due to saline groundwater exfiltration is an important issue. Fresh water diverted from the rivers is used for flushing the canals and the ditches in coastal areas to remove the low quality saline surface water mixed with saline groundwater. Worldwide, deltaic areas are under stress due to climate change, sea level increase and decrease in fresh water availability. The current fresh water management strategies in polders to overcome the salinization problem solely depends on uncontrolled freshwater use. However, this operation will not be effective during a scarce freshwater availability scenario and has to be revised for efficient management possibilities. With the advances in real time measurement of salinity and water level measurements, using a Model Predictive Control (MPC) scheme for the operation of a polder system is gaining popularity. MPC is a powerful control tool that can handle multiple objectives, consider the constraints and the uncertainties of the system. However, a MPC scheme requires a simple and reliable internal model that will be used to calculate the optimum control actions. The internal model should be robust, should reflect the system behaviour with enough detail and should not be computationally costly. In this paper, a MPC scheme is proposed using the discretized linearized De Saint Venant (SV) and Advection-Diffusion (AD) equations as the internal model of the controller. The proposed scheme will be able to control salinity and water level at any discretization point by manipulating the flushing and outflow discharges. This is an ongoing research with tests continuing on a realistic test case.
BibTeX:
@inproceedings{Aydin2018,
  author = {Boran Aydin and Martine Rutten and Edo Abraham},
  editor = {La Loggia,  Goffredo and Gabriele Freni and Valeria Puleo and De Marchis, Mauro},
  title = {Model Predictive Control of Salinity and Water Level in a Hypothetical Polder Ditch: Is it Possible to Use the Discretized Linearized Physical Equations for Optimization},
  booktitle = {EPiC Series in Engineering},
  publisher = {EasyChair},
  year = {2018},
  volume = {3},
  pages = {117--122},
  doi = {10.29007/rpmp}
}
Deuerlein J, Gilbert D, Abraham E and others (2018), "A Greedy Scheduling of Post-Disaster Response and Restoration using Pressure-Driven Models and Graph Segment Analysis", In WDSA/CCWI Joint Conference Proceedings. Kingston, Ontario, Canada, July, 2018. Vol. 1
BibTeX:
@inproceedings{Deuerlein2018,
  author = {Deuerlein, J and Gilbert, D and Abraham, E and others},
  title = {A Greedy Scheduling of Post-Disaster Response and Restoration using Pressure-Driven Models and Graph Segment Analysis},
  booktitle = {WDSA/CCWI Joint Conference Proceedings},
  year = {2018},
  volume = {1},
  url = {https://ojs.library.queensu.ca/index.php/wdsa-ccw/article/view/12180}
}
Stoianov I, Abraham E and Pecci F (2018), "Management of liquid conduit systems", #December#, 2018. Google Patents.
BibTeX:
@patent{Stoianov2018,
  author = {Stoianov, Ivan and Abraham, Edo and Pecci, Filippo},
  title = {Management of liquid conduit systems},
  publisher = {Google Patents},
  year = {2018},
  note = {US Patent App. 16/061,276}
}
Gilbert D, Abraham E, Montalvo I and Piller O (2017), "Iterative Multistage Method for a Large Water Network Sectorization into DMAs under Multiple Design Objectives", Journal of Water Resources Planning and Management. Vol. 143(11) American Society of Civil Engineers (ASCE).
Abstract: This paper considers the sectorization of a large water distribution network into district metered areas (DMAs) and simultaneously optimizes rehabilitation of the network with new pipes, control valves, and storage tanks. Since the available water resources are much smaller in the dry season, both the design and operational settings are optimized to satisfy water demand, water quality and pressure constraints, and efficiency indices under stringent conditions. Because of the heterogeneity of the multiple decision variables and the complicated way they interact through the multiple objectives (some complimentary and some conflicting), it is not possible to fully automize the simultaneous sectorization, rehabilitation and operational optimization. Therefore, we employ a multi-stage approach where engineering judgement and network graph simplification and visualization tools are employed to find a good feasible solution that is used as a first guess for further optimization of sectors and operational settings, to achieve feasible solutions with better cost of implementation, demand similarity among DMAs and better pressure uniformity in operations. A multi-objective Agent Swarm Optimization framework is used to iteratively change the sectors at the boundaries. For the final configuration, sequential linear programming is used to find optimal valve and pump settings.
BibTeX:
@article{223101b1f1a244a6861d47c119936a4e,
  author = {Denis Gilbert and E. Abraham and Idel Montalvo and Olivier Piller},
  title = {Iterative Multistage Method for a Large Water Network Sectorization into DMAs under Multiple Design Objectives},
  journal = {Journal of Water Resources Planning and Management},
  publisher = {American Society of Civil Engineers (ASCE)},
  year = {2017},
  volume = {143},
  number = {11},
  doi = {10.1061/(ASCE)WR.1943-5452.0000835}
}
Pecci F, Abraham E and Stoianov I (2017), "Penalty and relaxation methods for the optimal placement and operation of control valves in water supply networks", Computational Optimization and Applications., 5, 2017. Vol. 67(1), pp. 201-223. Springer Netherlands.
Abstract: In this paper, we investigate the application of penalty and relaxation methods to the problem of optimal placement and operation of control valves in water supply networks, where the minimization of average zone pressure is the objective. The optimization framework considers both the location and settings of control valves as decision variables. Hydraulic conservation laws are enforced as nonlinear constraints and binary variables are used to model the placement of control valves, resulting in a mixed-integer nonlinear program. We review and discuss theoretical and algorithmic properties of two solution approaches. These include penalty and relaxation methods that solve a sequence of nonlinear programs whose stationary points converge to a stationary point of the original mixed-integer program. We implement and evaluate the algorithms using a benchmarking water supply network. In addition, the performance of different update strategies for the penalty and relaxation parameters are investigated under multiple initial conditions. Practical recommendations on the numerical implementation are provided.
BibTeX:
@article{6b59e43d71c64deaa0aee9fdf1cd487a,
  author = {Filippo Pecci and Edo Abraham and Ivan Stoianov},
  title = {Penalty and relaxation methods for the optimal placement and operation of control valves in water supply networks},
  journal = {Computational Optimization and Applications},
  publisher = {Springer Netherlands},
  year = {2017},
  volume = {67},
  number = {1},
  pages = {201--223},
  doi = {10.1007/s10589-016-9888-z}
}
Abraham E (2017), "Sustainable Management of Water Distribution Systems Using Model-based Optimization Tools and Renewable Energy", In JDS International Seminar. Tsukuba University, January, 2017.
BibTeX:
@conference{Abraham2017,
  author = {Edo Abraham},
  title = {Sustainable Management of Water Distribution Systems Using Model-based Optimization Tools and Renewable Energy},
  booktitle = {JDS International Seminar},
  year = {2017}
}
Aydin B, Rutten M, Abraham E, Oude Essink G and Delsman J (2017), "Model Predictive Control of Salinity in a Polder Ditch under High Saline Groundwater Exfiltration Conditions: A Test Case", In 20h World Congress of the International Federation of Automatic Control (IFAC), 2017. Netherlands Vol. 50(1), pp. 3160-3164. Elsevier.
Abstract: Surface water salinization in deltaic areas due to saline groundwater exfiltration is an important issue. Saline surface water will not be appropriate for drinking water production, agricultural and industrial use, and therefore, freshwater diverted from rivers is used for flushing the canals and ditches in coastal areas. The effects of climate change, sea level increase and fresh water availability increases the stress on deltaic areas resulting in questioning current fresh water management strategies. In this paper, a Model Predictive Control (MPC) scheme is developed and tested for combined salinity and water level control of a polder ditch. The MPC scheme is coupled with Rapid Saline Groundwater Exfiltration Model (RSGEM) developed for fast calculation of exfiltration flux and concentration in a low-lying polder. For the test case presented in this paper, real data from Lissertocht catchment in Netherlands is used for RSGEM to see the performance of the MPC scheme for a real scenario. With open space for further research, results presented on this paper show that MPC of salinity in polders is capable of dealing with saline groundwater exfiltration modeled by RSGEM.
BibTeX:
@inproceedings{Aydin2017,
  author = {Boran Aydin and Martine Rutten and Edo Abraham and Oude Essink, GHP and Joost Delsman},
  editor = {D. Dochain and D. Henrion and D. Peaucelle},
  title = {Model Predictive Control of Salinity in a Polder Ditch under High Saline Groundwater Exfiltration Conditions: A Test Case},
  booktitle = {20h World Congress of the International Federation of Automatic Control (IFAC), 2017},
  publisher = {Elsevier},
  year = {2017},
  volume = {50},
  number = {1},
  pages = {3160--3164},
  edition = {1},
  url = {https://doi.org/10.1016/j.ifacol.2017.08.335},
  doi = {10.1016/j.ifacol.2017.08.335}
}
Pecci F, Abraham E and Stoianov I (2017), "Quadratic head loss approximations for optimisation problems in water supply networks", Journal of Hydroinformatics. Vol. 19(4), pp. 493-506. IWA Publishing.
Abstract: This paper presents a novel analysis of the accuracy of quadratic approximations for the Hazen--Williams (HW) head loss formula, which enables the control of constraint violations in optimisation problems for water supply networks. The two smooth polynomial approximations considered here minimise the absolute and relative errors, respectively, from the original non-smooth HW head loss function over a range of flows. Since quadratic approximations are used to formulate head loss constraints for different optimisation problems, we are interested in quantifying and controlling their absolute errors, which affect the degree of constraint violations of feasible candidate solutions. We derive new exact analytical formulae for the absolute errors as a function of the approximation domain, pipe roughness and relative error tolerance. We investigate the efficacy of the proposed quadratic approximations in mathematical optimisation problems for advanced pressure control in an operational water supply network. We propose a strategy on how to choose the approximation domain for each pipe such that the optimisation results are sufficiently close to the exact hydraulically feasible solution space. By using simulations with multiple parameters, the approximation errors are shown to be consistent with our analytical predictions.
BibTeX:
@article{d2d1cdecc94241ddb088e46421a8e075,
  author = {Filippo Pecci and Edo Abraham and Stoianov I},
  title = {Quadratic head loss approximations for optimisation problems in water supply networks},
  journal = {Journal of Hydroinformatics},
  publisher = {IWA Publishing},
  year = {2017},
  volume = {19},
  number = {4},
  pages = {493--506},
  doi = {10.2166/hydro.2017.080}
}
Menke R, Kadehjian K, Abraham E and Stoianov I (2017), "Investigating trade-offs between the operating cost and green house gas emissions from water distribution systems", Sustainable Energy Technologies and Assessments. Vol. 21, pp. 13-22. Elsevier.
Abstract: For electricity grids with an increasing share of intermittent renewables, the power generation mix can have significant daily variations. This leads to time-dependent emission intensities and volatile electricity prices in the day-ahead and spot market tariffs that can be better utilised by energy intensive industries such as water supply utilities. A multi-objective optimisation method for scheduling the operation of pumps is investigated in this paper for the reduction of both electricity costs and greenhouse gas emissions for a benchmark water distribution system. A set of energy supply scenarios has been formulated based on future projections from National Grid plc (UK) in order to investigate the range of cost savings and emission reductions that could be possibly achieved. Pump scheduling options with fixed time-of-use and day ahead market tariffs are analysed in order to compare potential reduction tradeoffs for both electricity costs and greenhouse gas emissions using Pareto optimality. The presented analysis concludes that the explicit inclusion of greenhouse gas emission reductions in optimising the scheduling of pumps operation in water distribution systems could provide considerable benefits; however, more compelling fiscal and regulatory incentives are needed.
BibTeX:
@article{d663c13fccd649b39445ec06c8052618,
  author = {Ruben Menke and K Kadehjian and Edo Abraham and Ivan Stoianov},
  title = {Investigating trade-offs between the operating cost and green house gas emissions from water distribution systems},
  journal = {Sustainable Energy Technologies and Assessments},
  publisher = {Elsevier},
  year = {2017},
  volume = {21},
  pages = {13--22},
  doi = {10.1016/j.seta.2017.03.002}
}
Pecci F, Abraham E and Stoianov I (2017), "Scalable Pareto set generation for multiobjective co-design problems in water distribution networks: a continuous relaxation approach", Structural and Multidisciplinary Optimization., 3, 2017. Vol. 55(3), pp. 857-869. Springer Verlag.
Abstract: In this paper, we study the multiobjective co-design problem of optimal valve placement and operation in water distribution networks, addressing the minimization of average pressure and pressure variability indices. The presented formulation considers nodal pressures, pipe flows and valve locations as decision variables, where binary variables are used to model the placement of control valves. The resulting optimization problem is a multiobjective mixed integer nonlinear optimization problem. As conflicting objectives, average zone pressure and pressure variability can not be simultaneously optimized. Therefore, we present the concept of Pareto optima sets to investigate the trade-offs between the two conflicting objectives and evaluate the best compromise. We focus on the approximation of the Pareto front, the image of the Pareto optima set through the objective functions, using the weighted sum, normal boundary intersection and normalized normal constraint scalarization techniques. Each of the three methods relies on the solution of a series of single-objective optimization problems, which are mixed integer nonlinear programs (MINLPs) in our case. For the solution of each single-objective optimization problem, we implement a relaxation method that solves a sequence of nonlinear programs (NLPs) whose stationary points converge to a stationary point of the original MINLP. The relaxed NLPs have a sparse structure that come from the sparse water network graph constraints. In solving the large number of relaxed NLPs, sparsity is exploited by tailored techniques to improve the performance of the algorithms further and render the approaches scalable for large scale networks. The features of the proposed scalarization approaches are evaluated using a published benchmarking network model.
BibTeX:
@article{e534a5ac07da4755ac270c91f3083f97,
  author = {Filippo Pecci and Edo Abraham and Ivan Stoianov},
  title = {Scalable Pareto set generation for multiobjective co-design problems in water distribution networks: a continuous relaxation approach},
  journal = {Structural and Multidisciplinary Optimization},
  publisher = {Springer Verlag},
  year = {2017},
  volume = {55},
  number = {3},
  pages = {857--869},
  doi = {10.1007/s00158-016-1537-8}
}
Ekin Aydin B, Rutten M, Oude Essink GH, Delsman J and Abraham E (2017), "Smart Salinity Management in Low-lying Deltaic Areas: A Model Predictive Control Scheme Applied to a Test Canal", In EGU General Assembly Conference Abstracts.
BibTeX:
@conference{EkinAydin2017,
  author = {Ekin Aydin, Boran and Rutten, Martine and Oude Essink, Gualbert HP and Delsman, Joost and Abraham, Edo},
  title = {Smart Salinity Management in Low-lying Deltaic Areas: A Model Predictive Control Scheme Applied to a Test Canal},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2017},
  url = {https://meetingorganizer.copernicus.org/EGU2017/EGU2017-14448.pdf}
}
Pecci F, Abraham E and Stoianov I (2017), "Outer approximation methods for the solution of co-design optimisation problems in water distribution networks", In IFAC-PapersOnLine. Netherlands Vol. 50(1), pp. 5373-5379. Elsevier.
Abstract: In the present manuscript, we red investigate and demonstrate the use of outer approximation methods for simultaneously optimising the placement and operation of control valves in water distribution networks. The problem definition results in a mixed-integer nonlinear program with nonconvex constraints. We simplify the formulation, compared to previous literature, in order to reduce the degree of nonlinearity in the constraints and decrease the total problem size. We then red formulate the application of outer approximation based methods for the generation of good quality local optimal solutions for red the considered co-design problem. Finally, we present the results of applying the developed techniques to two case studies, and also comparing the performances of the outer approximation approaches with those of other local mixed integer nonlinear programming solution methods.
BibTeX:
@inproceedings{Pecci2017,
  author = {Filippo Pecci and Edo Abraham and Ivan Stoianov},
  editor = {D. Peaucelle and D. Dochain and D. Henrion},
  title = {Outer approximation methods for the solution of co-design optimisation problems in water distribution networks},
  booktitle = {IFAC-PapersOnLine},
  publisher = {Elsevier},
  year = {2017},
  volume = {50},
  number = {1},
  pages = {5373--5379},
  edition = {1},
  doi = {10.1016/j.ifacol.2017.08.1069}
}
Abraham E and Stoianov I (2016), "Constraint preconditioned inexact Newton method for hydraulic simulation of large-scale water distribution networks", IEEE Transactions on Control of Network Systems. , pp. 610-619. IEEE Control Systems Society.
Abstract: Many sequential mathematical optimization methods and simulation-based heuristics for optimal control and design of water distribution networks rely on a large number of hydraulic simulations. In this paper, we propose an efficient inexact subspace Newton method for hydraulic analysis of water distribution networks. By using sparse and well-conditioned fundamental null space bases, we solve the nonlinear system of hydraulic equations in a lower-dimensional kernel space of the network incidence matrix. In the inexact framework, the Newton steps are determined by solving the Newton equations only approximately using an iterative linear solver. Since large water network models are inherently badly scaled, a Jacobian regularization is employed to improve the condition number of these linear systems and guarantee positive definiteness. After presenting a convergence analysis of the regularised inexact Newton method, we use the conjugate gradient (CG) method to solve the sparse reduced Newton linear systems. Since CG is not effective without good preconditioners, we propose tailored constraint preconditioners that are computationally cheap because they are based only on invariant properties of the null space linear systems and do not change with flows and pressures. The preconditioners are shown to improve the distribution of eigenvalues of the linear systems and so enable a more efficient use of the CG solver. Since contiguous Newton iterates can have similar solutions, each CG call is warm-started with the solution for a previous Newton iterate to accelerate its convergence rate. Operational network models are used to show the efficacy of the proposed preconditioners and the warm-starting strategy in reducing computational effort.
BibTeX:
@article{014cf92e004445749e636362c8641492,
  author = {Edo Abraham and Ivan Stoianov},
  title = {Constraint preconditioned inexact Newton method for hydraulic simulation of large-scale water distribution networks},
  journal = {IEEE Transactions on Control of Network Systems},
  publisher = {IEEE Control Systems Society},
  year = {2016},
  pages = {610--619},
  doi = {10.1109/TCNS.2016.2548418}
}
Herrera M, Abraham E and Stoianov I (2016), "A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks", Water Resources Management., 3, 2016. Vol. 30(5), pp. 1685-1699. Springer Netherlands.
Abstract: Water utilities face a challenge in maintaining a good quality of service under a wide range of operational management and failure conditions. Tools for assessing the resilience of water distribution networks are therefore essential for both operational and maintenance optimization. In this paper, a novel graph-theoretic approach for the assessment of resilience for large scale water distribution networks is presented. This is of great importance for the management of large scale water distribution systems, most models containing up to hundreds of thousands of pipes and nodes. The proposed framework is mainly based on quantifying the redundancy and capacity of all possible routes from demand nodes to their supply sources. This approach works well with large network sizes since it does not rely on precise hydraulic simulations, which require complex calibration processes and computation, while remaining meaningful from a physical and a topological point of view. The proposal is also tailored for the analysis of sectorised networks through a novel multiscale method for analysing connectivity, which is successfully tested in operational utility network models made of more than 100,000 nodes and 110,000 pipes.
BibTeX:
@article{324cb064c566405e8aafd4f9ceb33f9c,
  author = {Manuel Herrera and Edo Abraham and Ivan Stoianov},
  title = {A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks},
  journal = {Water Resources Management},
  publisher = {Springer Netherlands},
  year = {2016},
  volume = {30},
  number = {5},
  pages = {1685--1699},
  doi = {10.1007/s11269-016-1245-6}
}
Menke R, Abraham E, Parpas P and Stoianov I (2016), "Exploring Optimal Pump Scheduling in Water Distribution Networks with Branch and Bound Methods", Water Resources Management., 11, 2016. Vol. 30(14), pp. 5333-5349. Springer Netherlands.
Abstract: Water utilities can achieve significant savings in operating costs by optimising pump scheduling to improve efficiency and shift electricity consumption to low-tariff periods. Due to the complexity of the optimal scheduling problem, heuristic methods that cannot guarantee global optimality are often applied. This paper investigates formulations of the pump scheduling problem solved using a branch and bound method. Piecewise linear component approximations outperform non-linear approximations within application driven accuracy bounds and demand uncertainties. It is shown that the reduction of symmetry through the grouping of pumps significantly reduces the computational effort, whereas loops in the network have the opposite effect. The computational effort of including convex, non-linear pump operating, and maintenance cost functions is investigated. Using case studies, it is shown that linear and fixed-cost functions can be used to find schedules which, when simulated in a full hydraulic simulation, have performances that are within the solver optimality gap and the uncertainty of demand forecasts.
BibTeX:
@article{47b984b1a03648ba983550edcb685aa0,
  author = {Ruben Menke and Edo Abraham and Panos Parpas and Ivan Stoianov},
  title = {Exploring Optimal Pump Scheduling in Water Distribution Networks with Branch and Bound Methods},
  journal = {Water Resources Management},
  publisher = {Springer Netherlands},
  year = {2016},
  volume = {30},
  number = {14},
  pages = {5333--5349},
  doi = {10.1007/s11269-016-1490-8}
}
Abraham E and Stoianov I (2016), "An efficient null space inexact Newton method for hydraulic simulation of water distribution networks", ArXiv.org.
BibTeX:
@article{4bf764cbf53f41ee9b73bb14b1575ba4,
  author = {Edo Abraham and Ivan Stoianov},
  title = {An efficient null space inexact Newton method for hydraulic simulation of water distribution networks},
  journal = {ArXiv.org},
  year = {2016},
  url = {https://arxiv.org/abs/1602.02630}
}
Abraham E, Blokker E and Stoianov I (2016), "Network Analysis, Control Valve Placement and Optimal Control of Flow Velocity for Self-Cleaning Water Distribution Systems", In 18th Conference on Water Distribution System Analysis., 7, 2016. Vol. 186, pp. 576-583. Elsevier.
Abstract: In this paper, we consider the proactive control of flow velocities to maximise the self-cleaning capacity of the drinking water distribution systems under normal operations both through a change of the network topology and through an optimal control of pressure reducing valve (PRV) settings. Inspired by line outage flow distribution in electrical networks, we show how a fast network graph analysis of link closures can be used to estimate the potential changes in flow velocities, which are then used to determine the most favourable pipes for closure. Where closing of pipes cannot be used because of other conflicting objectives, we consider the optimal control of PRVs to maximise self-cleaning at peak demand periods. We formulate a novel optimisation problem to maximise the network operations for increased self-cleaning capacity, while satisfying hydraulic and regulatory pressure constraints at demand nodes. A new smooth objective function approximation for cleaning capacity of the network is proposed along with a scalable sequential convex programming method to solve the resulting valve optimization problems. We use a published benchmark network as a case study to show the efficacy of these new approaches.
BibTeX:
@inproceedings{Abraham2016a,
  author = {Edo Abraham and EJM Blokker and Ivan Stoianov},
  title = {Network Analysis, Control Valve Placement and Optimal Control of Flow Velocity for Self-Cleaning Water Distribution Systems},
  booktitle = {18th Conference on Water Distribution System Analysis},
  publisher = {Elsevier},
  year = {2016},
  volume = {186},
  pages = {576--583},
  doi = {10.1016/j.proeng.2017.03.272}
}
Menke R, Abraham E, Parpas P and Stoianov I (2016), "Demonstrating demand response from water distribution system through pump scheduling", Applied Energy., 5, 2016. Vol. 170, pp. 377-387. Elsevier.
Abstract: Significant changes in the power generation mix are posing new challenges for the balancing systems of the grid. Many of these challenges are in the secondary electricity grid regulation services and could be met through demand response (DR) services. We explore the opportunities for a water distribution system (WDS) to provide balancing services with demand response through pump scheduling and evaluate the associated benefits. Using a benchmark network and demand response mechanisms available in the UK, these benefits are assessed in terms of reduced green house gas (GHG) emissions from the grid due to the displacement of more polluting power sources and additional revenues for water utilities. The optimal pump scheduling problem is formulated as a mixed-integer optimisation problem and solved using a branch and bound algorithm. This new formulation finds the optimal level of power capacity to commit to the provision of demand response for a range of reserve energy provision and frequency response schemes offered in the UK. For the first time we show that DR from WDS can offer financial benefits to WDS operators while providing response energy to the grid with less greenhouse gas emissions than competing reserve energy technologies. Using a Monte Carlo simulation based on data from 2014, we demonstrate that the cost of providing the storage energy is less than the financial compensation available for the equivalent energy supply. The GHG emissions from the demand response provision from a WDS are also shown to be smaller than those of contemporary competing technologies such as open cycle gas turbines. The demand response services considered vary in their response time and duration as well as commitment requirements. The financial viability of a demand response service committed continuously is shown to be strongly dependent on the utilisation of the pumps and the electricity tariffs used by water utilities. Through the analysis of range of water demand scenarios and financial incentives using real market data, we demonstrate how a WDS can participate in a demand response scheme and generate financial gains and environmental benefits.
BibTeX:
@article{b5221f0acdbc45c4aca2b336ee5e1095,
  author = {Ruben Menke and Edo Abraham and Panos Parpas and Ivan Stoianov},
  title = {Demonstrating demand response from water distribution system through pump scheduling},
  journal = {Applied Energy},
  publisher = {Elsevier},
  year = {2016},
  volume = {170},
  pages = {377--387},
  doi = {10.1016/j.apenergy.2016.02.136}
}
Abraham E and Kerrigan EricC (2015), "Lower-order H∞ filter design for bilinear systems with bounded inputs", IEEE Transactions on Signal Processing., 2, 2015. Vol. 63(4), pp. 895-906. IEEE.
Abstract: We propose an optimization-based method for designing a lower order Luenberger-type state estimator, while providing L2-gain guarantees on the error dynamics when the estimator is used with the higher order system. Suitable filter parameters can be computed by modelling the bilinear system as a linear differential inclusion and solving a set of bilinear matrix inequality constraints. Since these constraints are nonconvex, in general, we also show that one can solve a suitably defined semi-definite program to compute a bound on the level of suboptimality. The design method also allows one to explicitly take account of linear parameter uncertainties in order to provide a priori robustness guarantees. The H-infinity estimator not only has lower real-time computational requirements compared with a Kalman filter, but also does not require knowledge of the noise spectrum. For a numerical example, we consider the estimation of the radiation force for a wave energy converter, where a low-order model is used to approximate the radiation dynamics.
BibTeX:
@article{41c4365d75f54e2ab7d1546ada1aec3b,
  author = {Edo Abraham and Kerrigan, Eric C.},
  title = {Lower-order H∞ filter design for bilinear systems with bounded inputs},
  journal = {IEEE Transactions on Signal Processing},
  publisher = {IEEE},
  year = {2015},
  volume = {63},
  number = {4},
  pages = {895--906},
  doi = {10.1109/TSP.2014.2385656}
}
Wright R, Abraham E, Parpas P and Stoianov I (2015), "Control of water distribution networks with dynamic DMA topology using strictly feasible sequential convex programming", Water Resources Research., 12, 2015. Vol. 51(12), pp. 9925-9941. American Geophysical Union.
Abstract: The operation of water distribution networks (WDN) with a dynamic topology is a recently pioneered approach for the advanced management of District Metered Areas (DMAs) that integrates novel developments in hydraulic modeling, monitoring, optimization, and control. A common practice for leakage management is the sectorization of WDNs into small zones, called DMAs, by permanently closing isolation valves. This facilitates water companies to identify bursts and estimate leakage levels by measuring the inlet flow for each DMA. However, by permanently closing valves, a number of problems have been created including reduced resilience to failure and suboptimal pressure management. By introducing a dynamic topology to these zones, these disadvantages can be eliminated while still retaining the DMA structure for leakage monitoring. In this paper, a novel optimization method based on sequential convex programming (SCP) is outlined for the control of a dynamic topology with the objective of reducing average zone pressure (AZP). A key attribute for control optimization is reliable convergence. To achieve this, the SCP method we propose guarantees that each optimization step is strictly feasible, resulting in improved convergence properties. By using a null space algorithm for hydraulic analyses, the computations required are also significantly reduced. The optimized control is actuated on a real WDN operated with a dynamic topology. This unique experimental program incorporates a number of technologies set up with the objective of investigating pioneering developments in WDN management. Preliminary results indicate AZP reductions for a dynamic topology of up to 6.5% over optimally controlled fixed topology DMAs.
BibTeX:
@article{667431ff20fa41d689de001441ebe739,
  author = {Robert Wright and Edo Abraham and Panos Parpas and Ivan Stoianov},
  title = {Control of water distribution networks with dynamic DMA topology using strictly feasible sequential convex programming},
  journal = {Water Resources Research},
  publisher = {American Geophysical Union},
  year = {2015},
  volume = {51},
  number = {12},
  pages = {9925--9941},
  doi = {10.1002/2015WR017466}
}
Abraham E and Stoianov I (2015), "Efficient preconditioned iterative methods for hydraulic simulation of large scale water distribution networks", Procedia Engineering., In Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI). Vol. 119w(1), pp. 623-632. Elsevier.
Abstract: In this paper, we consider the use of an efficient null space algorithm for hydraulic analysis that employs preconditioned conjugate gradient (PCG) methods for solving the Newton linear equations. Since large water network models are inherently badly conditioned, a Jacobian regularization is employed to improve the condition number to some degree, this resulting in an inexact Newton method whose analyses is presented. Based on this analysis, constraint preconditioners are used to improve the condition number further for more efficient use of CG solvers. Operational networks are used to study the computational properties of the various approaches.
BibTeX:
@inproceedings{Abraham2015,
  author = {Edo Abraham and Ivan Stoianov},
  title = {Efficient preconditioned iterative methods for hydraulic simulation of large scale water distribution networks},
  booktitle = {Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  journal = {Procedia Engineering},
  publisher = {Elsevier},
  year = {2015},
  volume = {119w},
  number = {1},
  pages = {623--632},
  doi = {10.1016/j.proeng.2015.08.915}
}
Herrera M, Abraham E and Stoianov I (2015), "Graph-theoretic surrogate measures for analysing the resilience of water distribution networks", Procedia Engineering., In Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI). Vol. 119(1), pp. 1241-1248. Elsevier.
Abstract: Hydraulic resilience can be formulated as a measure of the ability of a water distribution network to maintain a minimum level of service under operational and failure conditions. This paper explores a hybrid approach to bridge the gap between graph-theoretic and hydraulic measures of resilience. We extend the concept of geodesic distance of a pipeline by taking into account energy losses associated with flow. New random-walk algorithms evaluate hydraulically feasible routes and identify nodes with different levels of hydraulic resilience. The nodes with the lowest scores are further analysed by considering the availability and capacity of their supply routes.
BibTeX:
@inproceedings{Herrera2015,
  author = {Manuel Herrera and Edo Abraham and Ivan Stoianov},
  title = {Graph-theoretic surrogate measures for analysing the resilience of water distribution networks},
  booktitle = {Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  journal = {Procedia Engineering},
  publisher = {Elsevier},
  year = {2015},
  volume = {119},
  number = {1},
  pages = {1241--1248},
  doi = {10.1016/j.proeng.2015.08.985}
}
Wright R, Abraham E, Parpas P and Stoianov I (2015), "Optimized control of pressure reducing valves in water distribution networks with dynamic topology", Procedia Engineering., In Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI). Vol. 119(1), pp. 1003-1011. Elsevier.
Abstract: A dynamic topology aggregates zones in water distribution networks (WDNs) for improved pressure management and resilience to failure. Based on a sequential convex programming (SCP) approach, we propose an optimization method for the control of pressure reducing valves (PRV) in WDNs with dynamic topology. By restricting the SCP iterations to the feasible search space, we show that reliable convergence of the method is achieved. Using an experimental study in a large operational network, the optimization of PRV settings with a dynamic topology is shown to result in pressure reductions of 3.7% compared to optimized PRVs in a closed DMA structure.
BibTeX:
@inproceedings{Wright2015,
  author = {Robert Wright and E. Abraham and Panos Parpas and Ivan Stoianov},
  title = {Optimized control of pressure reducing valves in water distribution networks with dynamic topology},
  booktitle = {Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI)},
  journal = {Procedia Engineering},
  publisher = {Elsevier},
  year = {2015},
  volume = {119},
  number = {1},
  pages = {1003--1011},
  doi = {10.1016/j.proeng.2015.08.994}
}
Abraham E and Kerrigan EC (2013), "Optimal Active Control and Optimization of a Wave Energy Converter", IEEE Transactions on Sustainable Energy., April, 2013. Vol. 4(2), pp. 324-332.
Abstract: This paper investigates optimal active control schemes applied to a point absorber wave energy converter within a receding horizon fashion. A variational formulation of the power maximization problem is adapted to solve the optimal control problem. The optimal control method is shown to be of a bang-bang type for a power takeoff mechanism that incorporates both linear dampers and active control elements. We also consider a direct transcription of the optimal control problem as a general nonlinear program. A variation of the projected gradient optimization scheme is formulated and shown to be feasible and computationally inexpensive compared to a standard NLP solver. Since the system model is bilinear and the cost function is not convex quadratic, the resulting optimization problem is not a quadratic program. Results will be compared with an optimal command latching method to demonstrate the improvement in absorbed power. All time domain simulations are generated under irregular sea conditions.
BibTeX:
@article{6353624,
  author = {E. Abraham and E. C. Kerrigan},
  title = {Optimal Active Control and Optimization of a Wave Energy Converter},
  journal = {IEEE Transactions on Sustainable Energy},
  year = {2013},
  volume = {4},
  number = {2},
  pages = {324-332},
  doi = {10.1109/TSTE.2012.2224392}
}
Abraham E and Kerrigan EC (2013), "Estimator design for input-constrained bilinear systems with application to wave energy conversion", In 52nd IEEE Conference on Decision and Control., Dec, 2013. , pp. 5686-5691.
Abstract: This paper investigates low-order observer design for bilinear systems with input constraints. A bilinear Luenberger-type observer with an H-infinity performance measure is formulated and the resulting synthesis problem is posed as a matrix inequality optimization for a linear parameter varying system. The resulting (nonconvex) bilinear matrix inequality problem is then solved with an LMI-based algorithm to find low-order nominal and robust quadratically stable observers. The performance of these observers are compared with that of a Kalman filter. In addition to alleviating the need to know the noise spectrum and its lower real-time computational burden, the H-infinity filter is shown to be robust to model uncertainties. The online radiation force estimation problem for a wave energy converter with bilinear dynamics is considered as an example.
BibTeX:
@inproceedings{6760785,
  author = {E. Abraham and E. C. Kerrigan},
  title = {Estimator design for input-constrained bilinear systems with application to wave energy conversion},
  booktitle = {52nd IEEE Conference on Decision and Control},
  year = {2013},
  pages = {5686-5691},
  doi = {10.1109/CDC.2013.6760785}
}
Abraham E and Kerrigan EC (2012), "Optimal active control of a wave energy converter", In 2012 IEEE 51st IEEE Conference on Decision and Control (CDC). , pp. 2415-2420.
BibTeX:
@inproceedings{Abraham2012,
  author = {Abraham, Edo and Kerrigan, Eric C},
  title = {Optimal active control of a wave energy converter},
  booktitle = {2012 IEEE 51st IEEE Conference on Decision and Control (CDC)},
  year = {2012},
  pages = {2415--2420},
  url = {https://ieeexplore.ieee.org/abstract/document/6426993},
  doi = {10.1109/CDC.2012.6426993}
}