Pith. sign in

REVIEW 5 major objections 4 minor 40 references

Safe Deployment of Offline Reinforcement Learning via Input Convex Action Correction

T0 review · 5 major / 4 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read A learned convex cost surface, descended by gradient at deployment, is what makes offline RL safe enough to control a polymerisation reactor.

desk verdict Worth a serious referee: the PICNN action-correction idea is interesting and the benchmark is useful, but the paper never states what cost the PICNN is trained to predict, which makes the core gradient update unverifiable as written. read the letter →

arxiv 2507.22640 v1 pith:BO4C7TIW submitted 2025-07-30 eess.SY cs.AIcs.LGcs.SYstat.ML

classification eess.SYcs.AIcs.LGcs.SYstat.ML
keywords offlinereinforcementlearningprocesscontrolPICNNconvexactioncorrectionpolymerisationCSTRgradetransitionsimplicitQ-learningLyapunov-inspiredsafety
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Offline reinforcement learning is usually hard to trust in a chemical plant because a policy trained on historical data can propose unsafe actions in unfamiliar states. This paper claims that a deployment-time safety layer can fix that: learn a state-conditioned cost model that is convex in the control action, and at run time take gradient steps on that cost to correct whatever action the offline policy proposes. On a polymerisation CSTR with randomised-PI historical data, the authors report that corrected policies outperform the PI controllers and remain stable across startup, grade-change-down, and grade-change-up scenarios. They also introduce a reproducible simulator and offline datasets for those three scenarios, and show that implicit Q-learning is a far stronger offline baseline than behaviour cloning. The central practical claim is that offline RL becomes usable for high-stakes process control when a convex learned cost steers actions at deployment.

What carries the argument

The load-bearing object is the partially input convex neural network (PICNN) used as a learned cost model. A PICNN is a feedforward network built with non-negative weights on the action path and convex non-decreasing activations such as Softplus, so the output is convex in the control action $a$ while still representing the state $s$ through unconstrained hidden transformations. This convexity is what justifies the online update, gradient descent in Eq. 24 or the Newton step in Eq. 25, since it guarantees a well-defined minimum in action space and thus a stable, interpretable correction direction. The model is trained by MSE regression on the cost $c_t$, and at deployment it is queried for $\nabla_a \hat{c}_\phi(s,a)$ at every timestep, turning a learned cost landscape into a usable safety filter.

What would settle it

Run the corrected policy from a state deliberately outside the training-data coverage, such as reactor temperature just below the 365 K runaway threshold, and check whether one gradient step on $\hat{c}_\phi$ decreases the true cost $c_t = |e_{CP}| + |e_T|$; if the surrogate's gradient drives the true cost up or the temperature past the limit in any such probe, the Lyapunov-like assumption is broken.

Watch

Extended reading notes

Core claim

The paper's concrete claim is that action correction by gradient descent on a partially input convex neural network turns offline RL policies into controllers that are competitive with, or better than, the PI policies that generated the data. The corrected action, $a_{k+1} = a_k - \eta \nabla_a \hat{c}_\phi(s, a_k)$, descends a cost surface trained to approximate $c_t = |e_{CP}| + |e_T|$, the sum of absolute setpoint errors at time $t$. Because $\hat{c}_\phi$ is convex in the action for every state, the descent has a well-defined minimum and the correction is locally optimal. Empirically, the PICNN has worse pointwise fit than an ordinary neural network (MAE 2.20 vs 0.47, $R^2$ 0.73 vs 0.99) yet produces smoother, better-directed gradients that yield lower rollout costs; the paper interprets this as evidence that structural convexity matters more than predictive accuracy for safe control. It presents this as the first use of PICNNs as learned safety surrogates for deployment-time correction.

Load-bearing premise

The learned cost surface really points downhill toward safety: descending the PICNN's gradient at deployment is assumed to reduce future setpoint error and keep the reactor safe, though no Lyapunov inequality or safety certificate is verified.

Editorial extensions

If this is right

  • Weak behaviour-cloning policies can be rescued: in the grade-up scenario BC+ scores 66.9 versus 4.7 for BC, and across all scenarios the mean rises from 39.5 to 71.3.
  • IQL is already strong, with mean 92.0 across scenarios, and adding corrections gives a small mean gain to 92.3 while consistently improving worst-case rewards, for example startup minimum 81.1 versus 72.7.
  • The correction layer requires no retraining and no online exploration, so it can be wrapped around any offline policy without modifying its structure.
  • A cost model with worse pointwise predictions but convex-in-action structure can control a plant more reliably than a more accurate nonconvex model, because its gradients stay bounded and consistently directed.
  • With corrections, offline RL maintains stability across all 100 rollout episodes in all three scenarios, supporting its feasibility as a data-driven alternative to traditional control.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A test the paper leaves implicit is to run the corrected policy from states deliberately outside the offline data coverage, such as reactor temperature near the 365 K runaway threshold or with a large unobserved initiator concentration, and check whether the surrogate gradients still reduce true cost.
  • Because the observation space hides initiator and radical concentrations, the learned cost surface sees only a partially observed state; explicit state estimation or a partly observed formulation would show where the correction layer stops being a safety filter.
  • The reported 14x reward increase for BC in grade-up is relative to a normalized scale where the worst PI trajectory scores 0 and the best scores 100, so it reflects recovery from a very poor imitation baseline rather than a 14-fold reduction in physical tracking error.
  • The correction layer is policy-agnostic, so any successor offline algorithm or model-based controller could be wrapped with the same PICNN cost model after retraining the cost on whatever data are available.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

5 major / 4 minor

Summary. The paper introduces a Gymnasium-compatible simulation of an exothermic polymerisation CSTR with three grade-transition scenarios, generates offline datasets from randomly tuned PI controllers, trains behaviour cloning (BC) and implicit Q-learning (IQL) policies, and proposes a deployment-time safety layer that corrects policy actions by gradient descent on a partially input convex neural network (PICNN) trained as a state-conditioned cost model. Experiments report reward improvements when the PICNN correction is applied, and the abstract claims that offline RL combined with convex action correction can outperform traditional control and maintain stability across all scenarios.

Significance. The idea of using a PICNN as a learned convex cost surface for deployment-time action correction is interesting, policy-agnostic, and potentially useful for process control, and the detailed environment description with three scenarios and randomized PI datasets is a reasonable basis for benchmarking offline RL. However, the central mechanism is not yet established: the temporal alignment of the PICNN training label with the gradient update is unspecified, the Lyapunov-like stability assertion is unverified, the comparison against traditional control is weak, and the reward and cost functions share the same error terms, making part of the reported improvement a matter of construction. If these issues are resolved, the contribution would be valuable; in the current form, the safety and stability claims go beyond the evidence.

major comments (5)
  1. [§4.3, Eqs. (23)–(24)] The manuscript never states what label is used to train the PICNN cost model. Eq. (23) defines c_t as a function of the current state errors, which are causally independent of the current action a_t; Eq. (24) then descends ∇_a c_phi(s,a). If the training label paired with (s_t,a_t) is c_t, the gradient in Eq. (24) optimises a learned function whose target does not depend on a_t, and the observed improvements would be an artefact of clipping, step-size tuning, or state-dependent bias. To make the correction meaningful, c_phi must approximate the next-step cost c_{t+1} (or an explicit one-step cost) as a function of (s_t,a_t). Please state the exact label construction, and ideally release code or datasets so this necessary condition can be verified.
  2. [§3.3.2 and §5, Algorithm 1] The claim that the PICNN cost is 'analogous to a Lyapunov function' is an assertion, not a verified property. Convexity in a for fixed s guarantees a unique minimizer of the learned surrogate, but it says nothing about monotone decrease of the true cost c_t along closed-loop trajectories, and it provides no region-of-attraction estimate or constraint-satisfaction certificate. The abstract's unconditional 'maintain stability across all scenarios' is therefore unsupported. Either add verification (for example, checking V(s_{t+1}) ≤ V(s_t) over all rollouts and reporting worst-case constraint violations) or substantially soften the stability claim to an empirical observation.
  3. [§6.2.6 and Table 4] The claim that offline RL 'can outperform traditional control approaches' rests on comparing against the 'Data' row, which is the same population of randomly tuned PI controllers used to generate the training data. This is not a tuned traditional-control baseline; the factor-10 gain sampling deliberately includes poor controllers. Add a well-tuned PI or MPC baseline and report separate safety metrics (thermal-runaway count, maximum temperature, constraint violations, settling time) in addition to reward normalized to the random-PI spread.
  4. [§3.3.1–3.3.2 and §6] The evaluation reward (Eq. 20) is built from the same setpoint-error terms |e_CP|+|e_T| that define the cost (Eq. 23) the PICNN is trained to predict. Since the correction layer descends a learned surrogate of that cost, part of the reported reward improvement is by construction and does not independently validate safety. Report metrics that are not the training objective, and test robustness under disturbances or parameter perturbations outside the training distribution.
  5. [§3.3.1, Eq. (20)] The safety penalty in Eq. (20) is triggered when e_T < −50, i.e., when temperature is far below setpoint, yet the text and §3.4 define thermal runaway as occurring at approximately 365 K, which for a 350 K setpoint corresponds to e_T > 15. As written, the stated runaway penalty does not fire in the dangerous regime, so the reward does not encode the safety constraint claimed. Either correct the sign or threshold to a high-temperature condition or explain the discrepancy.
minor comments (4)
  1. [§3.4 and §6.2.1] Section 3.4 says the grade-up transition is 'comparatively simpler', but Section 6.2.1 describes the upward grade transition as 'the most difficult of the 3 CSTR scenarios'; these statements should be reconciled.
  2. [Throughout] There are numerous typos and grammatical errors, including 'cummulative' in §2.1, 'subobtimal' in §2.3, 'particulalry' and 'ulitimately' in §4.3, 'controlled an IQL agent' in §6.1, and 'the reactor the starting point' in §3.4. A careful proofread is needed.
  3. [§6.1, Figures 5 and 6] The rollout comparisons in Figures 5 and 6 report no numerical aggregates or statistical tests, and the shaded regions overlap substantially; the claimed differences in stability and gradient direction should be quantified.
  4. [§4.3, Table 3] The statement that the PICNN and standard NN were trained 'using the same parameters and architecture' is ambiguous, since the PICNN imposes additional structural constraints; clarify whether the comparison uses identical layer counts, widths, and parameter counts.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the PICNN action-correction layer is a model-based optimizer over an explicitly defined setpoint-error cost; evaluation and cost are aligned by design, and the paper's self-citations are background only.

full rationale

The paper's derivation chain is self-contained: reactor dynamics (Eqs. 15-19) are independent ODEs; the PI-generated offline datasets, BC and IQL training (Sec. 4.1-4.2), and PICNN cost training (Sec. 4.3) follow standard supervised/offline-RL pipelines. The deployment update (Eq. 24, a_{k+1} = a_k - eta * grad_a c_hat_phi(s,a_k)) descends the learned PICNN cost model; this is model-based action optimization, not a fitted input renamed as a prediction. It is true that the evaluation reward (Eq. 20-22) is built from the same setpoint-error terms that define the cost (Eq. 23: c_t = |e_t^CP| + |e_t^T|), and the paper explicitly says the cost is 'tightly aligned with operational safety and long-term control objectives.' This is deliberate objective alignment, not circularity: the environment reward/cost used in evaluation is computed from the simulator, not from the PICNN's own output, so measured improvements are not forced by construction—indeed Figure 4 shows the PICNN has materially worse pointwise fit (R^2 = 0.73 vs 0.99), so its rollout benefit is an empirical finding. Self-citations ([2], [28], [38]) are background references and are not load-bearing for the central claim; no uniqueness theorem or unverified prior claim is imported to forbid alternatives. Two correctness/verification gaps should be noted separately from circularity: the paper never specifies whether the PICNN label paired with (s_t, a_t) is c_t or c_{t+1}, which matters for whether grad_a c_hat_phi is causally meaningful (Eq. 23 vs Eq. 24), and Section 3.3.2's 'analogous to a Lyapunov function' is asserted without a verified Lyapunov inequality. Neither gap makes the derivation circular: they are missing evidence or unspecified implementation details, not reductions of a prediction to its own input.

Assumptions & free parameters 5 free parameters · 5 assumptions · 0 invented entities

The central claim rests on the simulator model, the cost-as-safety proxy, the coverage of PI-generated data, and the convex gradient-correction idea. The main free parameters are the correction step size, noise level, reward thresholds, and unstated clipping details, all of which can affect the reported gains.

free parameters (5)
  • Gradient correction step size eta = not reported; tuned on rollouts
    Section 6.2.3 says 'It was important to tune the step size of the gradient descent to balance responsiveness and stability, as too large a step could lead to larger overshoots and instability.' The value is not reported, making the reported gains hard to reproduce.
  • Thermal runaway threshold in reward = e_T < -50 K (Eq. 20)
    Hand-chosen safety threshold in the reward. The sign convention and the text 'drops below -50 C' are inconsistent, and this threshold directly shapes which trajectories are considered unsafe.
  • Measurement noise magnitude = not reported
    Section 3.3 says 'Noise is added on the process variables measurements to add complexity and realism', but no noise level is reported. This affects environment difficulty and policy evaluation.
  • IQL expectile and AWR temperature = tau = 0.9, beta = 5
    Algorithm hyperparameters chosen by hand in Section 4.2; they affect the learned value function and policy extraction and are not part of a systematic sensitivity study.
  • Correction clipping or projection bounds = unspecified
    Algorithm 1 line 13 says 'Optionally clip or project a_t to valid action bounds' without giving the method or the exact bounds for the delta actions. This is a free implementation parameter that can strongly affect stability.
assumptions (5)
  • domain assumption The ODE model (Eqs. 15-19) with Table 1 parameters accurately represents a polymerisation CSTR in all three scenarios.
    All training and evaluation happens in this simulator; no real-plant validation is provided. Entered in Section 3.1.
  • domain assumption The cost c_t = |e_CP| + |e_T| is an adequate proxy for operational safety and stability, analogous to a Lyapunov function.
    Section 3.3.2 explicitly calls this cost 'analogous to a Lyapunov function'. No theorem connects decreasing this cost to closed-loop stability or avoidance of thermal runaway.
  • standard math A PICNN that is convex in the action has a unique global minimum for each state, making gradient descent a reliable corrector.
    ICNN convexity gives global optimality for convex minimization, but uniqueness requires strict convexity, which the described architecture (Softplus, non-negative weights) does not guarantee. Asserted in Section 5.
  • domain assumption The PI-generated offline datasets provide sufficient state-action coverage for BC and IQL to learn a policy that generalizes across all scenarios.
    100 random PI tunings per scenario are assumed to cover the operational envelope; no coverage metric is given. Section 3.4.
  • ad hoc to paper Gradient descent on the learned PICNN cost surface improves safety in deployment without retraining or environment interaction.
    This is the core assumption of the proposed safety layer, stated in Section 5 and Algorithm 1. It is only tested empirically on this simulator, not proven.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Safe Deployment of Offline Reinforcement Learning via Input Convex Action Correction." pith.science (2026). https://pith.science/paper/BO4C7TIW

@misc{pith2026250722640,
  author       = {Pith},
  title        = {Pith review of: Safe Deployment of Offline Reinforcement Learning via Input Convex Action Correction},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/BO4C7TIW}},
  note         = {Machine review of arXiv:2507.22640}
}
read the original abstract

Offline reinforcement learning (offline RL) offers a promising framework for developing control strategies in chemical process systems using historical data, without the risks or costs of online experimentation. This work investigates the application of offline RL to the safe and efficient control of an exothermic polymerisation continuous stirred-tank reactor. We introduce a Gymnasium-compatible simulation environment that captures the reactor's nonlinear dynamics, including reaction kinetics, energy balances, and operational constraints. The environment supports three industrially relevant scenarios: startup, grade change down, and grade change up. It also includes reproducible offline datasets generated from proportional-integral controllers with randomised tunings, providing a benchmark for evaluating offline RL algorithms in realistic process control tasks. We assess behaviour cloning and implicit Q-learning as baseline algorithms, highlighting the challenges offline agents face, including steady-state offsets and degraded performance near setpoints. To address these issues, we propose a novel deployment-time safety layer that performs gradient-based action correction using input convex neural networks (PICNNs) as learned cost models. The PICNN enables real-time, differentiable correction of policy actions by descending a convex, state-conditioned cost surface, without requiring retraining or environment interaction. Experimental results show that offline RL, particularly when combined with convex action correction, can outperform traditional control approaches and maintain stability across all scenarios. These findings demonstrate the feasibility of integrating offline RL with interpretable and safety-aware corrections for high-stakes chemical process control, and lay the groundwork for more reliable data-driven automation in industrial systems.

Figures

Figures reproduced from arXiv: 2507.22640 by the authors.

Figure 1
Figure 1. Three different classes of reinforcement learning (taken from [30]). Offline reinforcement learning [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. PICNN architecture adapted from [9]. The network is convex in the action input [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗
Figure 3
Figure 3. Schematic of the polymerisation CSTR environment. Control actions include the initiator feed rate [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figures from the paper (21 more)
Figure 4
Figure 4. Figure 4: Comparison of standard NN and PICNN cost model predictions on training data from the poly [PITH_FULL_IMAGE:figures/full_fig_p014_4.png]
Figure 5
Figure 5. Figure 5: Comparison of environment cost feedback during rollouts of the polymerisation CSTR grade change [PITH_FULL_IMAGE:figures/full_fig_p014_5.png]
Figure 6
Figure 6. Figure 6: Comparison of gradients during rollouts of the polymerisation CSTR grade change up scenario [PITH_FULL_IMAGE:figures/full_fig_p015_6.png]
Figure 7
Figure 7. Figure 7: 100 rollouts comprising the polymerisation CSTR grade up dataset. [PITH_FULL_IMAGE:figures/full_fig_p016_7.png]
Figure 8
Figure 8. Figure 8: BC agent rollouts on the grade up scenario. [PITH_FULL_IMAGE:figures/full_fig_p017_8.png]
Figure 9
Figure 9. Figure 9: BC agent with online gradient-based action corrections on the grade up scenario. [PITH_FULL_IMAGE:figures/full_fig_p018_9.png]
Figure 10
Figure 10. Figure 10: IQL agent rollouts on the grade up scenario. [PITH_FULL_IMAGE:figures/full_fig_p019_10.png]
Figure 11
Figure 11. Figure 11: IQL agent with online gradient-based action corrections on the grade up scenario. [PITH_FULL_IMAGE:figures/full_fig_p020_11.png]
Figure 12
Figure 12. Figure 12: Total episode rewards for rollouts on the polymerisation CSTR grade up scenario. The boxplots [PITH_FULL_IMAGE:figures/full_fig_p021_12.png]
Figure 13
Figure 13. Figure 13: 100 PI controlled episodes from the polymerisation CSTR startup scenario. [PITH_FULL_IMAGE:figures/full_fig_p026_13.png]
Figure 14
Figure 14. Figure 14: 100 BC episodes for the startup scenario. [PITH_FULL_IMAGE:figures/full_fig_p027_14.png]
Figure 15
Figure 15. Figure 15: 100 IQL episodes for the startup scenario. [PITH_FULL_IMAGE:figures/full_fig_p027_15.png]
Figure 16
Figure 16. Figure 16: 100 episodes for the startup scenario controlled by the BC agent with online gradient correction. [PITH_FULL_IMAGE:figures/full_fig_p028_16.png]
Figure 17
Figure 17. Figure 17: 100 episodes for the startup scenario controlled by the IQL agent with online gradient correction. [PITH_FULL_IMAGE:figures/full_fig_p028_17.png]
Figure 18
Figure 18. Figure 18: Boxplot of rewards for the startup scenario. [PITH_FULL_IMAGE:figures/full_fig_p029_18.png]
Figure 19
Figure 19. Figure 19: 100 PI controlled episodes from the polymerisation CSTR grade change down scenario. [PITH_FULL_IMAGE:figures/full_fig_p030_19.png]
Figure 20
Figure 20. Figure 20: 100 BC episodes for the grade change down scenario. [PITH_FULL_IMAGE:figures/full_fig_p031_20.png]
Figure 21
Figure 21. Figure 21: 100 IQL episodes for the grade change down scenario. [PITH_FULL_IMAGE:figures/full_fig_p031_21.png]
Figure 22
Figure 22. Figure 22: 100 episodes for the grade change down scenario controlled by the BC agent with online gradient [PITH_FULL_IMAGE:figures/full_fig_p032_22.png]
Figure 23
Figure 23. Figure 23: 100 episodes for the grade change down scenario controlled by the IQL agent with online gradient [PITH_FULL_IMAGE:figures/full_fig_p032_23.png]
Figure 24
Figure 24. Figure 24: Boxplot of rewards for the grade change down scenario. [PITH_FULL_IMAGE:figures/full_fig_p033_24.png]

Discussion (0). Sign in to comment.

Reference graph

Works this paper leans on

40 extracted references · 21 canonical work pages

  1. [1]

    Reinforcement Learning: An Introduction,

    R. S. Sutton and A. Barto, “Reinforcement Learning: An Introduction,” 2018

  2. [2]

    From automated to autonomous process operations,

    M. Baldea, A. T. Georgiou, B. Gopaluni, M. Mercang¨ oz, C. C. Pantelides, K. Sheth, V. M. Zavala, and C. Georgakis, “From automated to autonomous process operations,” Computers & Chemical Engineer- ing, vol. 196, p. 109064, 2025

  3. [3]

    Concrete Problems in AI Safety,

    D. Amodei, C. Olah, J. Steinhardt, P. Christiano, J. Schulman, and D. Man´ e, “Concrete Problems in AI Safety,” 2016. [Online]. Available: https://arxiv.org/abs/1606.06565

  4. [4]

    Optimal grade transition for polyethylene reactors via NCO tracking,

    D. Bonvin, L. Bodizs, and B. Srinivasan, “Optimal grade transition for polyethylene reactors via NCO tracking,” Chemical Engineering Research and Design, vol. 83, no. 6, pp. 692–697, 2005

  5. [5]

    Iterative learning control-based batch process control technique for integrated control of end product properties and transient profiles of process variables,

    K. S. Lee and J. H. Lee, “Iterative learning control-based batch process control technique for integrated control of end product properties and transient profiles of process variables,”Journal of Process Control, vol. 13, no. 7, pp. 607–621, 2003

  6. [6]

    Integrated scheduling and dynamic optimization of grade transitions for a continuous polymerization reactor,

    A. Prata, J. Oldenburg, A. Kroll, and W. Marquardt, “Integrated scheduling and dynamic optimization of grade transitions for a continuous polymerization reactor,” Computers & Chemical Engineering, vol. 32, no. 3, pp. 463–476, 2008

  7. [7]

    The general problem of the stability of motion,

    A. M. Lyapunov, “The general problem of the stability of motion,” International Journal of Control, vol. 55, no. 3, pp. 531–534, 1992

  8. [8]

    H. K. Khalil and J. W. Grizzle, Nonlinear Systems, 3rd ed. Prentice Hall, 1996

Show all 40 references
  1. [9]

    Input Convex Neural Networks,

    B. Amos, L. Xu, and J. Z. Kolter, “Input Convex Neural Networks,” 2017. [Online]. Available: https://arxiv.org/abs/1609.07152 23

  2. [10]

    Safe Model-based Reinforcement Learning with Stability Guarantees,

    F. Berkenkamp, M. Turchetta, A. P. Schoellig, and A. Krause, “Safe Model-based Reinforcement Learning with Stability Guarantees,” 2017. [Online]. Available: https://arxiv.org/abs/1705.08551

  3. [11]

    Control Barrier Function Based Quadratic Pro- grams for Safety Critical Systems,

    A. D. Ames, X. Xu, J. W. Grizzle, and P. Tabuada, “Control Barrier Function Based Quadratic Pro- grams for Safety Critical Systems,” IEEE Transactions on Automatic Control, vol. 62, no. 8, pp. 3861– 3876, 2017

  4. [12]

    Safe and Stable RL (S2RL) Driving Policies Using Control Barrier and Control Lyapunov Functions,

    B. Gangopadhyay, P. Dasgupta, and S. Dey, “Safe and Stable RL (S2RL) Driving Policies Using Control Barrier and Control Lyapunov Functions,” IEEE Transactions on Intelligent Vehicles, vol. 8, no. 2, pp. 1889–1899, 2023

  5. [13]

    Constrained Policy Optimization,

    J. Achiam, D. Held, A. Tamar, and P. Abbeel, “Constrained Policy Optimization,” 2017. [Online]. Available: https://arxiv.org/abs/1705.10528

  6. [14]

    Safe Exploration in Continuous Action Spaces,

    G. Dalal, K. Dvijotham, M. Vecerik, T. Hester, C. Paduraru, and Y. Tassa, “Safe Exploration in Continuous Action Spaces,” 2018. [Online]. Available: https://arxiv.org/abs/1801.08757

  7. [15]

    Conservative Q-Learning for Offline Reinforcement Learning,

    A. Kumar, A. Zhou, G. Tucker, and S. Levine, “Conservative Q-Learning for Offline Reinforcement Learning,” 2020. [Online]. Available: https://arxiv.org/abs/2006.04779

  8. [16]

    Offline Reinforcement Learning with Implicit Q-Learning,

    I. Kostrikov, A. Nair, and S. Levine, “Offline Reinforcement Learning with Implicit Q-Learning,” 2021. [Online]. Available: https://arxiv.org/abs/2110.06169

  9. [17]

    MOPO: Model-based Offline Policy Optimization,

    T. Yu, G. Thomas, L. Yu, S. Ermon, J. Zou, S. Levine, C. Finn, and T. Ma, “MOPO: Model-based Offline Policy Optimization,” 2020. [Online]. Available: https://arxiv.org/abs/2005.13239

  10. [18]

    Actor–Critic Physics-Informed Neural Lyapunov Con- trol,

    J. Wang and M. Fazlyab, “Actor–Critic Physics-Informed Neural Lyapunov Con- trol,” IEEE Control Systems Letters , vol. 8, p. 1751–1756, 2024. [Online]. Available: http://dx.doi.org/10.1109/LCSYS.2024.3416235

  11. [19]

    Distributional Reinforcement Learning with Quantile Regression,

    W. Dabney, M. Rowland, M. G. Bellemare, and R. Munos, “Distributional Reinforcement Learning with Quantile Regression,” 2017. [Online]. Available: https://arxiv.org/abs/1710.10044

  12. [20]

    EKG-AC: A New Paradigm for Process Indus- trial Optimization Based on Offline Reinforcement Learning With Expert Knowledge Guidance,

    D. Liu, Y. Wang, C. Liu, B. Luo, and B. Huang, “EKG-AC: A New Paradigm for Process Indus- trial Optimization Based on Offline Reinforcement Learning With Expert Knowledge Guidance,” IEEE Transactions on Cybernetics, pp. 1–11, 2025

  13. [21]

    Optimal Control Via Neural Networks: A Convex Approach,

    Y. Chen, Y. Shi, and B. Zhang, “Optimal Control Via Neural Networks: A Convex Approach,” 2019. [Online]. Available: https://arxiv.org/abs/1805.11835

  14. [22]

    Differentiable Convex Optimization Layers,

    A. Agrawal, B. Amos, S. Barratt, S. Boyd, S. Diamond, and Z. Kolter, “Differentiable Convex Optimization Layers,” 2019. [Online]. Available: https://arxiv.org/abs/1910.12430

  15. [23]

    OptNet: Differentiable Optimization as a Layer in Neural Networks,

    B. Amos and J. Z. Kolter, “OptNet: Differentiable Optimization as a Layer in Neural Networks,”

  16. [24]

    Polymer grade transition control using advanced real-time optimization software,

    S. BenAmor, F. J. Doyle III, and R. McFarlane, “Polymer grade transition control using advanced real-time optimization software,” Journal of Process Control, vol. 14, no. 4, pp. 349–364, 2004

  17. [25]

    Polymer grade transition control via reinforcement learning trained with a physically consistent memory sequence-to-sequence digital twin,

    Z.-F. Jiang, D. S.-H. Wong, J.-L. Kang, Y. Yao, and Y.-C. Chuang, “Polymer grade transition control via reinforcement learning trained with a physically consistent memory sequence-to-sequence digital twin,” in Computer Aided Chemical Engineering. Elsevier, 2023, vol. 52, pp. 297–303

  18. [26]

    A benchmark environment motivated by industrial control problems,

    D. Hein, S. Depeweg, M. Tokic, S. Udluft, A. Hentschel, T. A. Runkler, and V. Sterzing, “A benchmark environment motivated by industrial control problems,” in 2017 IEEE Symposium Series on Computa- tional Intelligence (SSCI), 2017, pp. 1–8

  19. [27]

    Benchmarking Safe Exploration in Deep Reinforcement Learning,

    A. Ray, J. Achiam, and D. Amodei, “Benchmarking Safe Exploration in Deep Reinforcement Learning,” 2019. [Online]. Available: https://arxiv.org/abs/1910.01708 24

  20. [28]

    PC-Gym: Benchmark Environments For Process Control Problems,

    M. Bloor, J. Torraca, I. O. Sandoval, A. Ahmed, M. White, M. Mercang¨ oz, C. Tsay, E. A. D. R. Chanona, and M. Mowbray, “PC-Gym: Benchmark Environments For Process Control Problems,” arXiv preprint arXiv:2410.22093, 2024

  21. [29]

    End-to-End Safe Reinforcement Learning through Barrier Functions for Safety-Critical Continuous Control Tasks,

    R. Cheng, G. Orosz, R. M. Murray, and J. W. Burdick, “End-to-End Safe Reinforcement Learning through Barrier Functions for Safety-Critical Continuous Control Tasks,” 2019. [Online]. Available: https://arxiv.org/abs/1903.08792

  22. [30]

    Offline reinforcement learning methods for real-world problems,

    T. Kim, H. Suk, and S. Kim, “Offline reinforcement learning methods for real-world problems,” in Advances in Computers. Elsevier, 2024, vol. 134, pp. 285–315

  23. [31]

    Offline reinforcement learning: Tutorial, review, and perspectives on open problems,

    S. Levine, A. Kumar, G. Tucker, and J. Fu, “Offline reinforcement learning: Tutorial, review, and perspectives on open problems,” arXiv preprint arXiv:2005.01643, 2020

  24. [32]

    A survey on offline reinforcement learning: Taxonomy, review, and open problems,

    R. F. Prudencio, M. R. Maximo, and E. L. Colombini, “A survey on offline reinforcement learning: Taxonomy, review, and open problems,” IEEE Transactions on Neural Networks and Learning Systems, 2023

  25. [33]

    Stabilizing off-policy q-learning via bootstrapping error reduction,

    A. Kumar, J. Fu, M. Soh, G. Tucker, and S. Levine, “Stabilizing off-policy q-learning via bootstrapping error reduction,” Advances in neural information processing systems, vol. 32, 2019

  26. [34]

    Deep Reinforcement Learning with Double Q-learning,

    H. van Hasselt, A. Guez, and D. Silver, “Deep Reinforcement Learning with Double Q-learning,” 2015. [Online]. Available: https://arxiv.org/abs/1509.06461

  27. [35]

    Human-level control through deep reinforcement learning,

    V. Mnih, K. Kavukcuoglu, D. Silver, A. A. Rusu, J. Veness, M. G. Bellemare, A. Graves, M. Riedmiller, A. K. Fidjeland, G. Ostrovski et al., “Human-level control through deep reinforcement learning,”nature, vol. 518, no. 7540, pp. 529–533, 2015

  28. [36]

    Behavior Regularized Offline Reinforcement Learning,

    Y. Wu, G. Tucker, and O. Nachum, “Behavior Regularized Offline Reinforcement Learning,” 2019. [Online]. Available: https://arxiv.org/abs/1911.11361

  29. [37]

    Advantage-Weighted Regression: Simple and Scalable Off-Policy Reinforcement Learning,

    X. B. Peng, A. Kumar, G. Zhang, and S. Levine, “Advantage-Weighted Regression: Simple and Scalable Off-Policy Reinforcement Learning,” 2019. [Online]. Available: https://arxiv.org/abs/1910.00177

  30. [38]

    Comparative Study of Machine Learning and System Identification for Process Systems Engineering Dynamics,

    A. Ahmed, E. A. del Rio-Chanona, and M. Mercang¨ oz, “Comparative Study of Machine Learning and System Identification for Process Systems Engineering Dynamics,” Industrial & Engineering Chemistry Research, 2025

  31. [39]

    Polymerization reactor control using autoregressive-plus Volterra- based MPC,

    B. R. Maner and F. J. Doyle III, “Polymerization reactor control using autoregressive-plus Volterra- based MPC,” AIChE Journal, vol. 43, no. 7, pp. 1763–1784, 1997. 25 A Startup scenario results Figure 13: 100 PI controlled episodes from the polymerisation CSTR startup scenari...

  32. [2021]

    Available: https://arxiv.org/abs/1703.00443

    [Online]. Available: https://arxiv.org/abs/1703.00443

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.