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Geoscientific models are based on geoscientific data; hence, building better models, in the sense of attaining better predictions, often means acquiring additional data. In decision theory, questions of what additional data are expected to best improve predictions and decisions is within the realm of value of information and Bayesian optimal survey design. However, these approaches often evaluate the optimality of one additional data acquisition campaign at a time. In many real settings, certainly in those related to the exploration of Earth resources, a large sequence of data acquisition campaigns possibly needs to be planned. Geoscientific data acquisition can be expensive and time-consuming, requiring effective measurement campaign planning to optimally allocate resources. Each measurement in a data acquisition sequence has the potential to inform where best to take the following measurements; however, directly optimizing a closed-loop measurement sequence requires solving an intractable combinatoric search problem. In this work, we formulate the sequential geoscientific data acquisition problem as a partially observable Markov decision process (POMDP). We then present methodologies to solve the sequential problem using Monte Carlo planning methods. We demonstrate the effectiveness of the proposed approach on a simple 2D synthetic exploration problem. Tests show that the proposed sequential approach is significantly more effective at reducing uncertainty than conventional methods. Although our approach is discussed in the context of mineral resource exploration, it likely has bearing on other types of geoscientific model questions. [ABSTRACT FROM AUTHOR]

Geoscientific models are based on geoscientific data, hence building better models, in the sense of attaining better predictions, often means acquiring additional data. In decision theory questions of what additional data is expected to best improve predictions/decisions is within the realm of value of information and Bayesian optimal survey design. However, these approaches often evaluate the optimality of one additional data acquisition campaign at a time. In many real settings, certainly in those related to the exploration of Earth resources, possibly a large sequence of data acquisition campaigns need to be planned. Geoscientific data acquisition can be expensive and time consuming, requiring effective measurement campaign planning to optimally allocate resources. Each measurement in a data acquisition sequence has the potential to inform where best to take the following measurements, however, directly optimizing a closed-loop measurement sequence requires solving an intractable combinatoric search problem. In this work, we formulate the sequential geoscientific data acquisition problem as a Partially Observable Markov Decision Process (POMDP). We then present methodologies to solve the sequential problem using Monte Carlo planning methods. We demonstrate the effectiveness of the proposed approach on a simple 2D synthetic exploration problem. Tests show that the proposed sequential approach is significantly more effective at reducing uncertainty than conventional methods. Although our approach is discussed in the context of mineral resource exploration, it likely has bearing on other types of geoscientific model questions. [ABSTRACT FROM AUTHOR]

The optimal design of a wind farm which maximizes energy production depends on the spatially variable wind flow field. However, due to the complexity associated with modeling atmospheric winds, especially in the presence of complex terrain, the wind field is inherently uncertain. Uncertainty in the wind field during the design stage reduces the likelihood that the constructed wind farm achieves maximum energy production for a given number of turbines. As such, contemporary wind farms are designed through a two step process. First, experimental data collected from simultaneously constructed meteorological towers are used, along with simplified engineering flow models, to estimate the flow field. Then, the estimated flow field is used to place wind turbines to maximize an objective function, such as wind farm energy production. To increase wind farm energy production and reduce its uncertainty, we propose a farm design methodology that combines both the sensor placement and wind turbine location selection steps into a single sequential decision-making process. Future sensor placements sequentially leverage information gained from previous ones. Rather than placing sensors to attempt to reduce wind field uncertainty, we select sensor locations to maximize wind farm profit. Using profit as the objective function balances the increased revenue, from the increased energy production associated with improved wind field knowledge, against the higher costs from additional sensors. In this proof-of-concept study, we use idealized numerical case studies to demonstrate that sequential wind field sensor placement, compared to concurrent placement, improves the robustness of the resulting wind farm design to imperfect initial knowledge of the wind field. The numerical results suggest a wind farm annual energy output (lifetime profit) increase of approximately 6.55% (16.78%), equaling roughly 0.7 GWh/year (0.35 million USD) per turbine, compared to a typical, two-step wind farm design process which first places sensors concurrently then designs the farm thereafter. Our results also indicate that using a far-sighted sequential method as proposed in this paper outperforms standard metrics, such as entropy, that solely focus on wind field uncertainty minimization. These proof-of-concept findings suggest that future research should be dedicated to improving the wind farm design process through sequential decision-making under uncertainty. [Display omitted] [ABSTRACT FROM AUTHOR]

• Groundwater remediation planning and decision problem formulated as a partially observable Markov decision process (POMDP). • Comparison between POMDP and the conventional state-of-the-art optimization approaches, such as one-shot optimization and model predictive control (closed loop) optimization. • DESPOT, a state-of-the-art POMDP solver, outperforms optimization solution methods using PSO and hand-crafted heuristic solutions. • Optimizing the trade-off between information gathering and the performance of possible future scenarios via POMDP formulation. • Importance of belief updates, also known as inversion problems or history matching, in groundwater problems. Groundwater contamination causes significant groundwater supply risks that severely affect humans and livestock, especially in the era of climate change. Consequently, the need to develop and optimize remediation strategies such as pump and treat is indispensable. An effective and efficient strategy can reduce the spread of contaminants and cost of clean-up. However, developing such a strategy is challenging due to the inherent uncertainty and sequential nature of the problem. For example, taking actions such as drilling wells is interwoven with information gathering over time. In this paper, we formulate the groundwater remediation planning and decision problem as a partially observable Markov decision process (POMDP). A POMDP formulation allows planning by optimizing the trade-off between information gathering and the performance of possible future scenarios. We use a state-of-the-art POMDP solver called DESPOT for planning remediation strategies. The results show that DESPOT can yield much better remediation strategies than hand crafted heuristics and optimization methods. The superior performance of DESPOT is due to the incorporation of both previous information and future reward into the current decision. We also demonstrate the robustness of the POMDP formulation to measurement error. [ABSTRACT FROM AUTHOR]