J. Zatarain Salazar
Please Note
21 records found
1
Artificial Intelligence for Optimising Water Management and Control in Critical Infrastructures
Development and Policy Assessment of AI-based Solutions for Water Treatment Processes in European Countries
The research follows a dual-track approach combining engineering development and policy analysis. On the engineering side, the work develops and evaluates deep reinforcement learning (DRL) controllers for aeration optimisation within activated sludge systems using real operational data provided by SUEZ Digital Solutions. Two state-of-the-art agents, Soft Actor–Critic (SAC) and Twin-Delayed DDPG (TD3), are trained interactively on a linear model for aeration, to respect operational constraints and improve the process. The agents were trained with two different configurations: with and without a buffer of historical transitions that is used as previous knowledge. After training, the agents were benchmarked across multiple disturbance scenarios, generated from real data of energy price and inflow load. Results demonstrate significant improvements compared to baseline control, achieving lower energy consumption, stable dissolved oxygen levels, and better values of redox potential in the tank. These findings confirm the technical feasibility and scalability of DRL-based aeration control for real-world deployment.
On the policy side, the research explores the institutional and governance readiness for adopting AI-based control in critical water infrastructures across Italy, France, and the Netherlands through fifteen semi-structured interviews with regulators, utility managers, and researchers. Using the Transition Model Canvas (TMC) and Multi-Level Perspective (MLP) frameworks, the analysis identifies key barriers and leverage points. In the first group, fragmented governance, infrastructural limits, and lack of AI literacy among stakeholders at all levels were identified, while the second one included regulatory sandboxes, digital-skills training, and pilot projects. Comparative insights show that France benefits from strong national coordination and incumbents (SUEZ, Veolia), Italy faces heterogeneous regional governance and uneven digitalisation, while the Netherlands provides a model of integrated and innovation-oriented regulation.
By integrating both perspectives, the thesis proposes a Transition Model Canvas for AI-based wastewater infrastructure at a European level. It maps how landscape pressures (EU AI Act, Green Deal, and Urban Wastewater Treatment Directive recast) interact with regime actors and niche innovations to shape transition pathways. The work concludes with a set of policy and design recommendations for safe and responsible AI adoption, structured into short-, medium-, and long-term phases.
Overall, this thesis demonstrates that AI-based control systems can substantially improve energy efficiency, regulatory compliance, and sustainability in wastewater management. Their successful adoption, however, requires coordinated regulatory frameworks, skills, and investment in digital infrastructures. The study illustrates how combining systems engineering with policy analysis can support the responsible digital transformation of Europe’s critical water infrastructures. ...
The research follows a dual-track approach combining engineering development and policy analysis. On the engineering side, the work develops and evaluates deep reinforcement learning (DRL) controllers for aeration optimisation within activated sludge systems using real operational data provided by SUEZ Digital Solutions. Two state-of-the-art agents, Soft Actor–Critic (SAC) and Twin-Delayed DDPG (TD3), are trained interactively on a linear model for aeration, to respect operational constraints and improve the process. The agents were trained with two different configurations: with and without a buffer of historical transitions that is used as previous knowledge. After training, the agents were benchmarked across multiple disturbance scenarios, generated from real data of energy price and inflow load. Results demonstrate significant improvements compared to baseline control, achieving lower energy consumption, stable dissolved oxygen levels, and better values of redox potential in the tank. These findings confirm the technical feasibility and scalability of DRL-based aeration control for real-world deployment.
On the policy side, the research explores the institutional and governance readiness for adopting AI-based control in critical water infrastructures across Italy, France, and the Netherlands through fifteen semi-structured interviews with regulators, utility managers, and researchers. Using the Transition Model Canvas (TMC) and Multi-Level Perspective (MLP) frameworks, the analysis identifies key barriers and leverage points. In the first group, fragmented governance, infrastructural limits, and lack of AI literacy among stakeholders at all levels were identified, while the second one included regulatory sandboxes, digital-skills training, and pilot projects. Comparative insights show that France benefits from strong national coordination and incumbents (SUEZ, Veolia), Italy faces heterogeneous regional governance and uneven digitalisation, while the Netherlands provides a model of integrated and innovation-oriented regulation.
By integrating both perspectives, the thesis proposes a Transition Model Canvas for AI-based wastewater infrastructure at a European level. It maps how landscape pressures (EU AI Act, Green Deal, and Urban Wastewater Treatment Directive recast) interact with regime actors and niche innovations to shape transition pathways. The work concludes with a set of policy and design recommendations for safe and responsible AI adoption, structured into short-, medium-, and long-term phases.
Overall, this thesis demonstrates that AI-based control systems can substantially improve energy efficiency, regulatory compliance, and sustainability in wastewater management. Their successful adoption, however, requires coordinated regulatory frameworks, skills, and investment in digital infrastructures. The study illustrates how combining systems engineering with policy analysis can support the responsible digital transformation of Europe’s critical water infrastructures.
How to Distribute Water Fairly in Times of Scarcity
A Participatory and Simulation-Based Process towards Distribution Policies for Guadalajara’s Aquapheric with a Distributive Justice and Deep Uncertainty Approach
This project proposes a participatory and simulation-based process for designing a Decision Support Tool (DST) that could serve as the basis for a Distribution Policy for the Aquapheric. Such policy would determine how much water should flow in each segment of the Aquapheric under the current drought conditions based on a set of objectives selected by policymakers. The pool of objectives available was defined via an in-person participatory workshop that was conducted with over 26 members of the local government and academia. The Distributive Justice Principles framework was used to guide the ethical discussion during the workshop and to develop the mathematical formulations of the objectives. A problem formulation for a Multi-Objective Optimization algorithm was designed to find the best performing and best compromise policies for the objectives that policy-makers select on the DST.
The theoretical discussions in this research focus on how deep uncertainty, particularly that related to values, can be tackled by offering tools based on simple models, built with participatory knowledge co-creation processes and that enable learning and flexibility as opposed to robustness.
...
This project proposes a participatory and simulation-based process for designing a Decision Support Tool (DST) that could serve as the basis for a Distribution Policy for the Aquapheric. Such policy would determine how much water should flow in each segment of the Aquapheric under the current drought conditions based on a set of objectives selected by policymakers. The pool of objectives available was defined via an in-person participatory workshop that was conducted with over 26 members of the local government and academia. The Distributive Justice Principles framework was used to guide the ethical discussion during the workshop and to develop the mathematical formulations of the objectives. A problem formulation for a Multi-Objective Optimization algorithm was designed to find the best performing and best compromise policies for the objectives that policy-makers select on the DST.
The theoretical discussions in this research focus on how deep uncertainty, particularly that related to values, can be tackled by offering tools based on simple models, built with participatory knowledge co-creation processes and that enable learning and flexibility as opposed to robustness.
Modeling Water Resources for Everyone
Transparent and Effective Approaches for Complex Systems: Case Study of the Lower Omo Basin
Applied to the Lower Omo-Gibe River Basin in Ethiopia, the study employs Evolutionary Multi-Objective Direct Policy Search to identify 283 Pareto-optimal policies. Findings reveal nuanced trade-offs: irrigation-optimized policies eliminate demand deficits but reduce environmental flows by up to 48%, while environmentally-focused policies show opposite effects. Notably, mean power generation remains relatively consistent across policies, challenging assumptions about water resource allocation trade-offs.
HydroWizard introduces novel visualization techniques, including animated rule curves and system state graphs, enhancing strategy interpretability. Its versatility is demonstrated through application to diverse water systems, including the Zambezi River Basin.
This research marks a significant advancement in water resource modeling, offering an open-source, accessible tool for complex water system analysis. It contributes valuable insights for sustainable water management and sets a new standard for global water resource management studies, emerging as an innovative solution to intensifying water management challenges worldwide. ...
Applied to the Lower Omo-Gibe River Basin in Ethiopia, the study employs Evolutionary Multi-Objective Direct Policy Search to identify 283 Pareto-optimal policies. Findings reveal nuanced trade-offs: irrigation-optimized policies eliminate demand deficits but reduce environmental flows by up to 48%, while environmentally-focused policies show opposite effects. Notably, mean power generation remains relatively consistent across policies, challenging assumptions about water resource allocation trade-offs.
HydroWizard introduces novel visualization techniques, including animated rule curves and system state graphs, enhancing strategy interpretability. Its versatility is demonstrated through application to diverse water systems, including the Zambezi River Basin.
This research marks a significant advancement in water resource modeling, offering an open-source, accessible tool for complex water system analysis. It contributes valuable insights for sustainable water management and sets a new standard for global water resource management studies, emerging as an innovative solution to intensifying water management challenges worldwide.
Multi-Metrics Robustness Evaluation of Water Allocation Policies in the Nile River Basin
Navigating Deep Uncertainties
To evaluate the resilience of these policies against future uncertainties, a series of steps are involved. First, policies are generated using optimization techniques designed to identify the best strategies that could foster cooperation among the countries, while also addressing their individual objectives. These strategies are then tested for their effectiveness under various future scenarios, which is done by applying robustness metrics. A robustness metric is a quantitative measure used to assess the resilience and stability of a system or process in the face of uncertainties, disturbances, or perturbations. It provides a way to quantify how well a system can maintain its performance or functionality under varying conditions. These metrics can range from assessing absolute performance or regret prioritizing risk-aversion, maximizing performance, or minimizing variance, depending on the specific uncertainties and the decision-maker's risk tolerance. However, many previous studies done on robustness of reservoir control rely on the 90th Percentile Regret metric which looks at how much worse a given strategy performs compared to the best possible outcome. While useful and practical, this approach doesn’t fully capture the range of different ways to test against future scenarios.
This research reveals that the choice of robustness metric can greatly affect the evaluation of different policies. Using four different metrics, we were able to conclude different “most robust” policies. Using minimax regret metric, Compromise Policie(s) are the most robust. However, using Undesirable Deviations metric, Best Egypt Irrigation Policy is the most robust. Using Percentile-Based Skewness yields Compromise: Percentile and Best Sudan Irrigation Policy as the most robust, and using Mean-Variance metric, only Best Sudan Irrigation policy emerged as the most robust. This variation occurs because different robustness metric prioritizes different aspects of policy performance under uncertainty. While the regret metric focuses on minimizing the worst-case scenario outcomes, other metrics like Percentile-Based Skewness emphasize the consistency of outcomes across a range of scenarios.
These findings emphasize the importance of using a diverse set of robustness metrics in policy evaluation. A diverse set of metrics allows for a more comprehensive assessment of policies by capturing different aspects of performance and risk under uncertainty. Depending on which metric is used, different strategies may be recommended, leading to potentially different outcomes for the countries involved. While strategies may seem mutually exclusive, a more nuanced approach can involve balancing the trade-offs highlighted by the various metrics, leading to a more informed and robust decision-making process. ...
To evaluate the resilience of these policies against future uncertainties, a series of steps are involved. First, policies are generated using optimization techniques designed to identify the best strategies that could foster cooperation among the countries, while also addressing their individual objectives. These strategies are then tested for their effectiveness under various future scenarios, which is done by applying robustness metrics. A robustness metric is a quantitative measure used to assess the resilience and stability of a system or process in the face of uncertainties, disturbances, or perturbations. It provides a way to quantify how well a system can maintain its performance or functionality under varying conditions. These metrics can range from assessing absolute performance or regret prioritizing risk-aversion, maximizing performance, or minimizing variance, depending on the specific uncertainties and the decision-maker's risk tolerance. However, many previous studies done on robustness of reservoir control rely on the 90th Percentile Regret metric which looks at how much worse a given strategy performs compared to the best possible outcome. While useful and practical, this approach doesn’t fully capture the range of different ways to test against future scenarios.
This research reveals that the choice of robustness metric can greatly affect the evaluation of different policies. Using four different metrics, we were able to conclude different “most robust” policies. Using minimax regret metric, Compromise Policie(s) are the most robust. However, using Undesirable Deviations metric, Best Egypt Irrigation Policy is the most robust. Using Percentile-Based Skewness yields Compromise: Percentile and Best Sudan Irrigation Policy as the most robust, and using Mean-Variance metric, only Best Sudan Irrigation policy emerged as the most robust. This variation occurs because different robustness metric prioritizes different aspects of policy performance under uncertainty. While the regret metric focuses on minimizing the worst-case scenario outcomes, other metrics like Percentile-Based Skewness emphasize the consistency of outcomes across a range of scenarios.
These findings emphasize the importance of using a diverse set of robustness metrics in policy evaluation. A diverse set of metrics allows for a more comprehensive assessment of policies by capturing different aspects of performance and risk under uncertainty. Depending on which metric is used, different strategies may be recommended, leading to potentially different outcomes for the countries involved. While strategies may seem mutually exclusive, a more nuanced approach can involve balancing the trade-offs highlighted by the various metrics, leading to a more informed and robust decision-making process.
Deep Uncertainty in Multi-Objective Optimization
Leveraging Robustness Analysis to Improve Adaptive Policy Design for River Basin Management - A Case Study
Disaggregating for justice in a multi-purpose reservoir system
Finding the possibilities and limitations of objective disaggregation in an EMODPS model of the Zambezi River Basin
In light of the DAFNE project, funded by the EU to create a Decision-Analytic Framework (DAF), an Evolutionary Multi Objective Direct Policy Search (EMODPS) framework was applied to the ZRB. EMODPS models combine Direct Policy Search (DPS) with Multi-Objective Evolutionary Algorithms (MOEA) to process complex simulations and continuously optimize for sequential decisions. The ZRB EMODPS model was created to identify the Pareto-optimal release policies for the five hydropower reservoirs and eight irrigation districts in the river basin. In the modelling process, there was a lack of consideration for distributive justice. In the baseline configuration, the five reservoirs were aggregated into one hydropower objective and the eight irrigation districts in the system were aggregated into one irrigation objective. The environmental flow at the Zambezi Delta constituted the third objective for the initial optimization.
This research disaggregates the hydropower and irrigation objectives to analyse what the effects are on the optimal release policies, particularly for smaller irrigation districts and reservoirs. The research question is: How does the disaggregation of objectives influence the Pareto space for an EMODPS simulation-optimization model? Four levels of aggregation were optimized: the baseline configuration with three objectives, the irrigation case with 11 objectives (including an individual objective for each irrigation district), the hydropower case with eight objectives (including the five hydropower reservoirs as objectives) and the full case with 16 objectives in total where the three baseline objectives are complemented with one objective for each irrigation district and hydropower reservoir. The Pareto set of the four different problem framings is visualized and analysed to conduct a comparison between the levels of aggregation.
Higher levels of aggregation may limit the insights provided by the Pareto front and increase the risk of further burdening marginalized groups. The initial hypothesis was that smaller irrigation districts and hydropower reservoirs would benefit from being considered as individual objectives. However, this hypothesis was not confirmed. The baseline aggregation of three objectives yielded better results for the total hydropower and irrigation deficits, even for the smaller districts and reservoirs.
The results reveal that disaggregation provides a more nuanced understanding of trade-offs but increases computational demands and complexity. The increased number of variables and constraints decreased the efficiency of the Generational Borg algorithm, making the study less feasible. Many-objective optimizations with more than 10 objectives pushed computational limits, displayed unexpected convergence behaviour, and posed challenges in presenting and interpreting large amounts of data. More sophisticated algorithms may better handle the consequences and limitations of objective aggregation in EMODPS models. This research highlights the trade-offs between equity and efficiency in water resource management and provides insights into the possibilities of disaggregating objectives for more just and precise policy-making.
...
In light of the DAFNE project, funded by the EU to create a Decision-Analytic Framework (DAF), an Evolutionary Multi Objective Direct Policy Search (EMODPS) framework was applied to the ZRB. EMODPS models combine Direct Policy Search (DPS) with Multi-Objective Evolutionary Algorithms (MOEA) to process complex simulations and continuously optimize for sequential decisions. The ZRB EMODPS model was created to identify the Pareto-optimal release policies for the five hydropower reservoirs and eight irrigation districts in the river basin. In the modelling process, there was a lack of consideration for distributive justice. In the baseline configuration, the five reservoirs were aggregated into one hydropower objective and the eight irrigation districts in the system were aggregated into one irrigation objective. The environmental flow at the Zambezi Delta constituted the third objective for the initial optimization.
This research disaggregates the hydropower and irrigation objectives to analyse what the effects are on the optimal release policies, particularly for smaller irrigation districts and reservoirs. The research question is: How does the disaggregation of objectives influence the Pareto space for an EMODPS simulation-optimization model? Four levels of aggregation were optimized: the baseline configuration with three objectives, the irrigation case with 11 objectives (including an individual objective for each irrigation district), the hydropower case with eight objectives (including the five hydropower reservoirs as objectives) and the full case with 16 objectives in total where the three baseline objectives are complemented with one objective for each irrigation district and hydropower reservoir. The Pareto set of the four different problem framings is visualized and analysed to conduct a comparison between the levels of aggregation.
Higher levels of aggregation may limit the insights provided by the Pareto front and increase the risk of further burdening marginalized groups. The initial hypothesis was that smaller irrigation districts and hydropower reservoirs would benefit from being considered as individual objectives. However, this hypothesis was not confirmed. The baseline aggregation of three objectives yielded better results for the total hydropower and irrigation deficits, even for the smaller districts and reservoirs.
The results reveal that disaggregation provides a more nuanced understanding of trade-offs but increases computational demands and complexity. The increased number of variables and constraints decreased the efficiency of the Generational Borg algorithm, making the study less feasible. Many-objective optimizations with more than 10 objectives pushed computational limits, displayed unexpected convergence behaviour, and posed challenges in presenting and interpreting large amounts of data. More sophisticated algorithms may better handle the consequences and limitations of objective aggregation in EMODPS models. This research highlights the trade-offs between equity and efficiency in water resource management and provides insights into the possibilities of disaggregating objectives for more just and precise policy-making.
Towards Just Policy
Identifying Distributive Justice Principles in a Global Climate Policy Context
Exploring distributive justice in water resource allocation
A rival framings approach on the operationalization of equality in multi-objective optimization models for water systems
...
Several water allocation simulations have been developed in the ENB using both linear and nonlinear programs to aid decision-making, but only two studies have previously examined measures of stability for these optimization results, and neither has been done since the completion of the GERD. Moreover, as simulation complexity has increased, there is a gap in knowledge regarding the measurement of stability using optimization results from closed-loop, multi-objective adaptive simulations.
To address this gap, this research reexamines the stability of policy candidates for water allocations in the ENB using three different solution concepts from cooperative game theory—the Nash-Harsanyi solution, the Shapley value, and the nucleolus. The stability of each policy candidate is assessed using three different stability metrics—the Euclidean distance, the Loehman Power Index, and the propensity to disrupt—to determine their relative stability. The approach yields similar objective trade-offs and utility behaviors for the Nash-Harsanyi and Shapley Values. The most stable policies, when ranked by Euclidean distance, prioritize Ethiopia’s utility, while policies become more unstable with the rapid growth of Egypt’s utility. Furthermore, propensities to disrupt and power indices between Egypt and Ethiopia or Sudan show converging and diverging behaviors, respectively, which explain the negotiation potentials between the players. Our results indicate that Egypt’s willingness to engage in collaboration is directly related to its level of utility; however, at these levels, Ethiopia and Sudan’s benefits from utility are at levels that prompt higher likelihoods of defections from a potential coalition. The results also showed stable policies characterized with high policy efficiencies in instances of basin-wide cooperation, which increases benefits to all nations.
Given the different assumptions and characteristics of each stability concept, the insights on the stability of different policies provide general guidelines for incorporating stability into the optimization formulation itself. The results have larger implications for policy planners in the ENB and the difficulties they may face when finding acceptable solutions in multi-stakeholder decision arenas. Furthermore, the methodological contribution of this study could allow for easy application of this method to other water allocation conflicts to help guide policy planners detect opportunities for utility optimization or risk mitigation in a cooperative setting. ...
Several water allocation simulations have been developed in the ENB using both linear and nonlinear programs to aid decision-making, but only two studies have previously examined measures of stability for these optimization results, and neither has been done since the completion of the GERD. Moreover, as simulation complexity has increased, there is a gap in knowledge regarding the measurement of stability using optimization results from closed-loop, multi-objective adaptive simulations.
To address this gap, this research reexamines the stability of policy candidates for water allocations in the ENB using three different solution concepts from cooperative game theory—the Nash-Harsanyi solution, the Shapley value, and the nucleolus. The stability of each policy candidate is assessed using three different stability metrics—the Euclidean distance, the Loehman Power Index, and the propensity to disrupt—to determine their relative stability. The approach yields similar objective trade-offs and utility behaviors for the Nash-Harsanyi and Shapley Values. The most stable policies, when ranked by Euclidean distance, prioritize Ethiopia’s utility, while policies become more unstable with the rapid growth of Egypt’s utility. Furthermore, propensities to disrupt and power indices between Egypt and Ethiopia or Sudan show converging and diverging behaviors, respectively, which explain the negotiation potentials between the players. Our results indicate that Egypt’s willingness to engage in collaboration is directly related to its level of utility; however, at these levels, Ethiopia and Sudan’s benefits from utility are at levels that prompt higher likelihoods of defections from a potential coalition. The results also showed stable policies characterized with high policy efficiencies in instances of basin-wide cooperation, which increases benefits to all nations.
Given the different assumptions and characteristics of each stability concept, the insights on the stability of different policies provide general guidelines for incorporating stability into the optimization formulation itself. The results have larger implications for policy planners in the ENB and the difficulties they may face when finding acceptable solutions in multi-stakeholder decision arenas. Furthermore, the methodological contribution of this study could allow for easy application of this method to other water allocation conflicts to help guide policy planners detect opportunities for utility optimization or risk mitigation in a cooperative setting.
Robust decision making for future train maintenance
Illustrating the abilities of decision making under deep uncertainty within the train maintenance context
Catching the trigger?
Including automated event data in interstate conflict prediction
To predict three separate problems, tree ensemble classifiers were used. The three outcomes to be predicted were the occurrence of interstate conflict, its onset, and its escalation. They were predicted globally at the dyad month level, meaning monthly for every country pair, using data from 1995 to 2014. The feature set consisted of eleven structural, slow-changing variables, and 268 event features, which were event counts on a dyad month according to event type.
The analysis showed that event data did not increase performance. This held across all three prediction problems. Additionally, it was found that the models for occurrence and escalation and performed well and decently well, respectively, but that the models for conflict onset performed poorly.
In conclusion, event data needs further testing in different constellations to be effective in interstate conflict prediction. It seems likely, however, that effective prediction for policy guidance is possible, given the model performance of the occurrence and escalation models. ...
To predict three separate problems, tree ensemble classifiers were used. The three outcomes to be predicted were the occurrence of interstate conflict, its onset, and its escalation. They were predicted globally at the dyad month level, meaning monthly for every country pair, using data from 1995 to 2014. The feature set consisted of eleven structural, slow-changing variables, and 268 event features, which were event counts on a dyad month according to event type.
The analysis showed that event data did not increase performance. This held across all three prediction problems. Additionally, it was found that the models for occurrence and escalation and performed well and decently well, respectively, but that the models for conflict onset performed poorly.
In conclusion, event data needs further testing in different constellations to be effective in interstate conflict prediction. It seems likely, however, that effective prediction for policy guidance is possible, given the model performance of the occurrence and escalation models.
Exploring Distributive Justice In Many-Objective Optimization
A Comparative Analysis of A Priori and A Posteriori Approaches to Implementing Distributive Justice Principles
Policy Tree Optimization for Climate Policy Modelling
An EPA Master Thesis
The 'Forest BORG' framework, based on the BORG multi-objective evolutionary algorithm (MOEA), is introduced as a method for optimizing policy trees in socio-economic systems. This framework accommodates tree-structured decision variables through specialized evolutionary operators, enabling multi-objective and explainable decision support. Tested on the Folsom lake model and the Regional Integrated model of Climate and the Economy (RICE) Integrated Assessment Model (IAM), Forest BORG addresses the challenges of optimizing multi-objective problems under deep uncertainty, primarily driven by climate change.
The Folsom lake model and RICE IAM serve as suitable case studies due to their reflection of real-life problems affected by climate change and involving multiple stakeholders. The XLRM framework is employed to operationalize the conceptual models of these case studies, categorizing uncertainties (X), levers (L), relations (R), and metrics (M).
Positioned between current MOEA capabilities and the need for explainable policies in real-world multi-objective problems under deep uncertainty, Forest BORG undergoes rigorous testing. Analyses include run-time dynamics, Forest BORG specific evolutionary operator dynamics, controllability, exposed trade-offs, and highlighted policy trees.
The framework employs seven mutation operators, crossover with prune and bloat control operations as the recombination operator, and an adaptive tournament size function as the selection operator. The performance and behavior of Forest BORG are evaluated through the five analyses mentioned.
Run-time dynamics demonstrate the algorithm's effective convergence based on hypervolume. Search operator dynamics investigate novel mutation operators, showcasing their contribution. Controllability analysis explores the impact of hyperparameter settings on algorithm performance. Exposed trade-offs are visualized through pareto-optimal policy alternatives, emphasizing the selection of compromise policies. The highlighted policy trees provide insight into actionable decisions based on different objectives.
Forest BORG proves effective, efficient, and reliable across case studies. Comparative analysis with the original policy optimization tree (POT) algorithm reinforces its effectiveness. Although the expected shift from subtree to point mutations was not observed in all cases, the search operators enhance overall search capability. Hyperparameters are case study-dependent, with modest maximum depths favored to avoid overfitting.
Forest BORG successfully produces pareto fronts for each case study, revealing inherent trade-offs. The selected policy trees align with performance metrics, providing valuable insights for decision-makers. However, some results exhibit counter-intuitive behavior, notably in the RICE model trade-offs and small peaks in run-time analysis, attributed to epsilon values.
The research suggests further exploration of other IAMs for a more realistic representation of reality. Forest BORG's societal contribution lies in its development and application to real-world case studies, expanding the range of multi-objective decision-making tools for socio-environmental systems. The implications extend to addressing climate change through policy development, emphasizing the potential for broader applications beyond the tested case studies. ...
The 'Forest BORG' framework, based on the BORG multi-objective evolutionary algorithm (MOEA), is introduced as a method for optimizing policy trees in socio-economic systems. This framework accommodates tree-structured decision variables through specialized evolutionary operators, enabling multi-objective and explainable decision support. Tested on the Folsom lake model and the Regional Integrated model of Climate and the Economy (RICE) Integrated Assessment Model (IAM), Forest BORG addresses the challenges of optimizing multi-objective problems under deep uncertainty, primarily driven by climate change.
The Folsom lake model and RICE IAM serve as suitable case studies due to their reflection of real-life problems affected by climate change and involving multiple stakeholders. The XLRM framework is employed to operationalize the conceptual models of these case studies, categorizing uncertainties (X), levers (L), relations (R), and metrics (M).
Positioned between current MOEA capabilities and the need for explainable policies in real-world multi-objective problems under deep uncertainty, Forest BORG undergoes rigorous testing. Analyses include run-time dynamics, Forest BORG specific evolutionary operator dynamics, controllability, exposed trade-offs, and highlighted policy trees.
The framework employs seven mutation operators, crossover with prune and bloat control operations as the recombination operator, and an adaptive tournament size function as the selection operator. The performance and behavior of Forest BORG are evaluated through the five analyses mentioned.
Run-time dynamics demonstrate the algorithm's effective convergence based on hypervolume. Search operator dynamics investigate novel mutation operators, showcasing their contribution. Controllability analysis explores the impact of hyperparameter settings on algorithm performance. Exposed trade-offs are visualized through pareto-optimal policy alternatives, emphasizing the selection of compromise policies. The highlighted policy trees provide insight into actionable decisions based on different objectives.
Forest BORG proves effective, efficient, and reliable across case studies. Comparative analysis with the original policy optimization tree (POT) algorithm reinforces its effectiveness. Although the expected shift from subtree to point mutations was not observed in all cases, the search operators enhance overall search capability. Hyperparameters are case study-dependent, with modest maximum depths favored to avoid overfitting.
Forest BORG successfully produces pareto fronts for each case study, revealing inherent trade-offs. The selected policy trees align with performance metrics, providing valuable insights for decision-makers. However, some results exhibit counter-intuitive behavior, notably in the RICE model trade-offs and small peaks in run-time analysis, attributed to epsilon values.
The research suggests further exploration of other IAMs for a more realistic representation of reality. Forest BORG's societal contribution lies in its development and application to real-world case studies, expanding the range of multi-objective decision-making tools for socio-environmental systems. The implications extend to addressing climate change through policy development, emphasizing the potential for broader applications beyond the tested case studies.
Climate Justice Behind the Veil of Aggregation
IAMs, Equity, and Pareto-Optimal Abatement Pathways
In order to account for distributional justice, we transform the RICE model into a simulation model and embed it in a many-objective simulation-optimization setup such that we can find Pareto-optimal climate mitigation pathways for different problem formulations. Next to using four ethical premises (rooted in utilitarianism, sufficientarianism, egalitarianism, and prioritarianism), we also direct particular attention to the disaggregation of utility and disutility within each of these ethical premises. The reason for this disaggregation is based on the incommensurability of these two. Usually, IAMs maximize aggregate variables such as welfare. If we also consider the minimization of welfare loss, which is based on economic damages as one of the objectives, we can enable a potentially fairer distribution of not only consumption but economic damages. We argue that we can find climate justice behind the veil of aggregation. What we mean by this is that more equitable policy recommendations are obscured and lie hidden behind a bulwark of highly aggregated variables. If we look beyond this obstruction by the means of disaggregation, we are better equipped to find climate justice. In order to get to the bottom of this, we ask the following question:
How are Pareto-optimal climate abatement pathways affected by the disaggregation of utility and disutility in alternative ethical problem formulations when using an integrated assessment model under deep uncertainty?
To answer this question, we use a framework that is called multi-scenario multi-objective robust decision-making. For each of the eight problem formulations (4 ethical premises x 2 levels of aggregation), we use a multi-objective evolutionary algorithm to find Pareto-optimal policies. We reevaluate their performances under uncertainty by comparing their climate abatement pathways across the problem formulations. On a high-level, we can summarize our key findings as:
- dominance of aggregation levels over ethical premises
- correlation between low welfare and high welfare loss
- general dominance of egalitarian aggregated Pareto-optimal policies
- shared misery via egalitarian disaggregated Pareto-optimal policies
The effect of disaggregating utility and disutility is stronger than originally expected. Using disaggregated problem formulations yields substantially different pathways even within the same ethical premise. These results are promising as we could transfer these insights to other more complex IAMs such as IMAGE and MESSAGE. Overall, this could be also good news for the equity debate. Using alternative ethical premises and disaggregating incommensurate objectives such as utility and disutility can offer alternative policy recommendations and resulting climate abatement pathways which could in turn enable more equity. What we likely need now, is a stronger dialogue between the modelers and policy analysts on the one side and the stakeholders and decision-makers on the other side. The latter ones should not just blindly trust in the magical outputs of a model but they need to be involved to decide what problem formulations we need to use as there is no correct way to frame a complex real-world problem. As unmitigated climate damages exhibit an independent impact on a region's well-being, we could render IAMs more useful for climate policy if we a) acknowledge that the classical notion of welfare is obsolete, b) use a multi-objective approach, and c) let the decision-makers decide how they want to trade-off the various objectives in post. In this manner, we could use IAMs to advance into the direction of enabling a transition of more climate justice.
...
In order to account for distributional justice, we transform the RICE model into a simulation model and embed it in a many-objective simulation-optimization setup such that we can find Pareto-optimal climate mitigation pathways for different problem formulations. Next to using four ethical premises (rooted in utilitarianism, sufficientarianism, egalitarianism, and prioritarianism), we also direct particular attention to the disaggregation of utility and disutility within each of these ethical premises. The reason for this disaggregation is based on the incommensurability of these two. Usually, IAMs maximize aggregate variables such as welfare. If we also consider the minimization of welfare loss, which is based on economic damages as one of the objectives, we can enable a potentially fairer distribution of not only consumption but economic damages. We argue that we can find climate justice behind the veil of aggregation. What we mean by this is that more equitable policy recommendations are obscured and lie hidden behind a bulwark of highly aggregated variables. If we look beyond this obstruction by the means of disaggregation, we are better equipped to find climate justice. In order to get to the bottom of this, we ask the following question:
How are Pareto-optimal climate abatement pathways affected by the disaggregation of utility and disutility in alternative ethical problem formulations when using an integrated assessment model under deep uncertainty?
To answer this question, we use a framework that is called multi-scenario multi-objective robust decision-making. For each of the eight problem formulations (4 ethical premises x 2 levels of aggregation), we use a multi-objective evolutionary algorithm to find Pareto-optimal policies. We reevaluate their performances under uncertainty by comparing their climate abatement pathways across the problem formulations. On a high-level, we can summarize our key findings as:
- dominance of aggregation levels over ethical premises
- correlation between low welfare and high welfare loss
- general dominance of egalitarian aggregated Pareto-optimal policies
- shared misery via egalitarian disaggregated Pareto-optimal policies
The effect of disaggregating utility and disutility is stronger than originally expected. Using disaggregated problem formulations yields substantially different pathways even within the same ethical premise. These results are promising as we could transfer these insights to other more complex IAMs such as IMAGE and MESSAGE. Overall, this could be also good news for the equity debate. Using alternative ethical premises and disaggregating incommensurate objectives such as utility and disutility can offer alternative policy recommendations and resulting climate abatement pathways which could in turn enable more equity. What we likely need now, is a stronger dialogue between the modelers and policy analysts on the one side and the stakeholders and decision-makers on the other side. The latter ones should not just blindly trust in the magical outputs of a model but they need to be involved to decide what problem formulations we need to use as there is no correct way to frame a complex real-world problem. As unmitigated climate damages exhibit an independent impact on a region's well-being, we could render IAMs more useful for climate policy if we a) acknowledge that the classical notion of welfare is obsolete, b) use a multi-objective approach, and c) let the decision-makers decide how they want to trade-off the various objectives in post. In this manner, we could use IAMs to advance into the direction of enabling a transition of more climate justice.
Characterizing the spatio-temporal dynamics of social vulnerability in Burkina Faso
A comparison of Principal Component Analysis with Equal Weighting
The results showed that despite drawbacks, principal component analysis provides good insight in de internal and externaly dynamics of social vulnerability. However, large differences are found in the ranking of the social vulnerability score of communes when other methods are used. Hence, it is deemed important to develop more research in the semantic meaning of social vulnerability an thus understand better which mathicmatical approach is the most suitable.
This research has found the highest social vulnerability in communes prone to conflict which are hosting many IDPs in the North, Centre-Nord, Sahel and East of the country. A statistically significant increase of social vulnerability was found from 2015 - 2017 in Boucle du Mouhoun, the Nord and the Centre-Nord. ...
The results showed that despite drawbacks, principal component analysis provides good insight in de internal and externaly dynamics of social vulnerability. However, large differences are found in the ranking of the social vulnerability score of communes when other methods are used. Hence, it is deemed important to develop more research in the semantic meaning of social vulnerability an thus understand better which mathicmatical approach is the most suitable.
This research has found the highest social vulnerability in communes prone to conflict which are hosting many IDPs in the North, Centre-Nord, Sahel and East of the country. A statistically significant increase of social vulnerability was found from 2015 - 2017 in Boucle du Mouhoun, the Nord and the Centre-Nord.
Trans-boundary water management modeling framework
How cooperation impacts water resources in a river basin
of maintaining dams operational versus satisfying the demand and 3) increased demand pressure reinforces trade-offs between Egypt’s aggregate deficit minimisation and Ethiopia’s hydropower maximisation objectives. Our results highlight the potential of compromise policies in managing the objectives of all stakeholders without imposing heavy sacrifices. These policies represent an opportunity for cooperative operation of the dams through which multiple challenges facing the basin can be addressed. ...
of maintaining dams operational versus satisfying the demand and 3) increased demand pressure reinforces trade-offs between Egypt’s aggregate deficit minimisation and Ethiopia’s hydropower maximisation objectives. Our results highlight the potential of compromise policies in managing the objectives of all stakeholders without imposing heavy sacrifices. These policies represent an opportunity for cooperative operation of the dams through which multiple challenges facing the basin can be addressed.
Will the Benefits Keep Flowing?
Analysing the Effects of an Uncertain World on the Objectives of the Akosombo Dam
Multi-sector Water Allocation
The impact of nonlinear approximation network hyperparameters for multi-objective reservoir control