npv
- Asia > India (0.14)
- North America > Canada (0.04)
An approach of deep reinforcement learning for maximizing the net present value of stochastic projects
Xu, Wei, Yang, Fan, Cui, Qinyuan, Chen, Zhi
This paper investigates a project with stochastic activity durations and cash flows under discrete scenarios, where activities must satisfy precedence constraints generating cash inflows and outflows. The objective is to maximize expected net present value (NPV) by accelerating inflows and deferring outflows. We formulate the problem as a discrete-time Markov Decision Process (MDP) and propose a Double Deep Q-Network (DDQN) approach. Comparative experiments demonstrate that DDQN outperforms traditional rigid and dynamic strategies, particularly in large-scale or highly uncertain environments, exhibiting superior computational capability, policy reliability, and adaptability. Ablation studies further reveal that the dual-network architecture mitigates overestimation of action values, while the target network substantially improves training convergence and robustness. These results indicate that DDQN not only achieves higher expected NPV in complex project optimization but also provides a reliable framework for stable and effective policy implementation.
Neural Path Features and Neural Path Kernel: Understanding the role of gates in deep learning Chandrashekar Lakshminarayanan and Amit Vikram Singh
A deep neural network (DNN) with ReLU activations has many gates, and the on/off status of each gate changes across input examples as well as network weights. For a given input example, only a subset of gates are active, i.e., on, and the sub-network of weights connected to these active gates is responsible for producing
- Asia > India (0.14)
- North America > Canada (0.04)
Improving Confidence in Evolutionary Mine Scheduling via Uncertainty Discounting
Stimson, Michael, Reid, William, Neumann, Aneta, Ratcliffe, Simon, Neumann, Frank
Long-term planning and production scheduling are among the most critical tasks in the area of mining. The goal is to extract valuable ore from an orebody in a sequence that takes into account many mining and precedence constraints in a way that is economically efficient [1]. This is an important real-world optimisation problem that has been studied in the literature over many years. This includes mixed integer programming approaches based on block scheduling [2, 3]. Each block in a block model (a discretised spatial approximation of the mineral deposit) has a given estimated value based on the metal grade and the excavation cost. Other heuristic techniques include dealing with specific characteristics such as uncertainties of the problem [4-6]. Different software products that offer a variety of approaches for mine planning and extraction sequences are available [7, 8]. Evolutionary computation techniques have successfully been applied in the area of mining, in particular to large scale optimisation problems such as the cost efficient extraction of ore [9, 10], the ore processing and blending problem [11-15], and the large-scale open pit mine scheduling problem [16, 17]. Particle swarm algorithms were utilised to solve the capacity constrained open pit mining problem [18] and the transportation and layout problem of locating a crushing station in an open-pit mine [19].
- Oceania > Australia > South Australia > Adelaide (0.05)
- North America > Canada > Quebec > Montreal (0.04)
Where Does the Population Vector of Motor Cortical Cells Point during Reaching Movements?
Visually-guided arm reaching movements are produced by distributed neural networks within parietal and frontal regions of the cerebral cortex. Experimental data indicate that (I) single neurons in these regions are broadly tuned to parameters of movement; (2) appropriate commands are elaborated by populations of neurons; (3) the coordinated action of neu(cid:173) rons can be visualized using a neuronal population vector (NPV). How(cid:173) ever, the NPV provides only a rough estimate of movement parameters (direction, velocity) and may even fail to reflect the parameters of move(cid:173) ment when arm posture is changed. We designed a model of the cortical motor command to investigate the relation between the desired direction of the movement, the actual direction of movement and the direction of the NPV in motor cortex. The model is a two-layer self-organizing neural network which combines broadly-tuned (muscular) proprioceptive and (cartesian) visual information to calculate (angular) motor commands for the initial part of the movement of a two-link arm.
Extending F1 metric, probabilistic approach
This article explores the extension of well-known F1 score used for assessing the performance of binary classifiers. We propose the new metric using probabilistic interpretation of precision, recall, specificity, and negative predictive value. We describe its properties and compare it to common metrics. Then we demonstrate its behavior in edge cases of the confusion matrix. Finally, the properties of the metric are tested on binary classifier trained on the real dataset.
- North America > United States > Wisconsin (0.04)
- Europe > Poland > Lesser Poland Province > Kraków (0.04)
Bayesian Emulation for Computer Models with Multiple Partial Discontinuities
Vernon, Ian, Owen, Jonathan, Carter, Jonathan
Computer models are widely used across a range of scientific disciplines to describe various complex physical systems, however to perform full uncertainty quantification we often need to employ emulators. An emulator is a fast statistical construct that mimics the slow to evaluate computer model, and greatly aids the vastly more computationally intensive uncertainty quantification calculations that an important scientific analysis often requires. We examine the problem of emulating computer models that possess multiple, partial discontinuities occurring at known non-linear location. We introduce the TENSE framework, based on carefully designed correlation structures that respect the discontinuities while enabling full exploitation of any smoothness/continuity elsewhere. This leads to a single emulator object that can be updated by all runs simultaneously, and also used for efficient design. This approach avoids having to split the input space into multiple subregions. We apply the TENSE framework to the TNO Challenge II, emulating the OLYMPUS reservoir model, which possess multiple such discontinuities.
- Health & Medicine > Therapeutic Area (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Multi-Asset Closed-Loop Reservoir Management Using Deep Reinforcement Learning
Nasir, Yusuf, Durlofsky, Louis J.
Closed-loop reservoir management (CLRM), in which history matching and production optimization are performed multiple times over the life of an asset, can provide significant improvement in the specified objective. These procedures are computationally expensive due to the large number of flow simulations required for data assimilation and optimization. Existing CLRM procedures are applied asset by asset, without utilizing information that could be useful over a range assets. Here, we develop a CLRM framework for multiple assets with varying numbers of wells. We use deep reinforcement learning to train a single global control policy that is applicable for all assets considered. The new framework is an extension of a recently introduced control policy methodology for individual assets. Embedding layers are incorporated into the representation to handle the different numbers of decision variables that arise for the different assets. Because the global control policy learns a unified representation of useful features from multiple assets, it is less expensive to construct than asset-by-asset training (we observe about 3x speedup in our examples). The production optimization problem includes a relative-change constraint on the well settings, which renders the results suitable for practical use. We apply the multi-asset CLRM framework to 2D and 3D water-flooding examples. In both cases, four assets with different well counts, well configurations, and geostatistical descriptions are considered. Numerical experiments demonstrate that the global control policy provides objective function values, for both the 2D and 3D cases, that are nearly identical to those from control policies trained individually for each asset. This promising finding suggests that multi-asset CLRM may indeed represent a viable practical strategy.
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Reinforcement Learning (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks > Deep Learning (0.46)
- Information Technology > Artificial Intelligence > Machine Learning > Learning Graphical Models > Undirected Networks > Markov Models (0.46)
Deep reinforcement learning for optimal well control in subsurface systems with uncertain geology
Nasir, Yusuf, Durlofsky, Louis J.
A general control policy framework based on deep reinforcement learning (DRL) is introduced for closed-loop decision making in subsurface flow settings. Traditional closed-loop modeling workflows in this context involve the repeated application of data assimilation/history matching and robust optimization steps. Data assimilation can be particularly challenging in cases where both the geological style (scenario) and individual model realizations are uncertain. The closed-loop reservoir management (CLRM) problem is formulated here as a partially observable Markov decision process, with the associated optimization problem solved using a proximal policy optimization algorithm. This provides a control policy that instantaneously maps flow data observed at wells (as are available in practice) to optimal well pressure settings. The policy is represented by a temporal convolution and gated transformer blocks. Training is performed in a preprocessing step with an ensemble of prior geological models, which can be drawn from multiple geological scenarios. Example cases involving the production of oil via water injection, with both 2D and 3D geological models, are presented. The DRL-based methodology is shown to result in an NPV increase of 15% (for the 2D cases) and 33% (3D cases) relative to robust optimization over prior models, and to an average improvement of 4% in NPV relative to traditional CLRM. The solutions from the control policy are found to be comparable to those from deterministic optimization, in which the geological model is assumed to be known, even when multiple geological scenarios are considered. The control policy approach results in a 76% decrease in computational cost relative to traditional CLRM with the algorithms and parameter settings considered in this work.
- Workflow (0.86)
- Research Report (0.82)
- Energy > Renewable (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.35)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Reinforcement Learning (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks > Deep Learning (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Learning Graphical Models > Undirected Networks > Markov Models (1.00)