Research Blog

Research Blog

Paper reviews organized by application systems and algorithmic methods. Just as elite athletes train every day, serious researchers read strong papers every day.

Application Reviews

Application Reviews

Reviews grouped by the systems where optimization, AI, and decision tools are applied.

Algorithmic Reviews

Algorithmic Reviews

Reviews grouped by the computational method, with emphasis on assumptions, evidence, and feasibility-critical limits.

Latest Research Notes

Mathematical Optimization

PEAR: Which Prediction Errors Actually Change the Decision?

A constrained optimizer cannot react to every prediction error. PEAR keeps the directions that can move the decision, making it most natural when system dynamics and constraints stay fixed while objective coefficients change across instances.

Decision-Focused Learning via Tangent-Space Projection of Prediction Error

Safe & Constrained RL

CAffNet: Hard Constraint-Affine Neural Networks

CAffNet embeds input-dependent affine constraints in a neural output layer. It guarantees feasibility for known nonempty constraint sets, but its combinatorial active-set cost and model-dependent safety assumptions remain central limitations.

CAffNet: Hard Constraint-Affine Neural Networks

Safe & Constrained RL

The Safety–Information Deadlock in Adaptive Probabilistic Shielding

How online MDP estimation, interval uncertainty, and probabilistic shielding form a coupled loop in which blocking risky actions can also block the evidence needed to learn safety.

Mathematical Optimization

Learning the Objective, Not the Schedule: Inverse Optimization for Expert Production Planning

A critical note on learning interpretable objective weights from expert production plans while preserving a known industrial MILP.

Uncovering expert objectives in production planning via inverse optimization: An industrial case study

LLM & Probabilistic Approaches

Denoising Score Matching: Why a Conditional Target Learns the Marginal Score

Diffusion models need the marginal score to reverse a noising process. This note explains why a tractable conditional Gaussian target learns that score and in what sense the two losses are equivalent.

Stanford CME296 Diffusion & Large Vision Models | Spring 2026 | Lecture 2 - Score matching

Chemical Plants

Beyond Minimum Reboiler Duty: Evaluating CO₂ Capture Solvents under Variable Conditions

A solvent with the lowest nominal reboiler duty may still require the tightest circulation control. This note separates energy efficiency, disturbance sensitivity, and ease of operation in an Aspen Plus comparison of MEA and MDEA/PZ solvents.

Robust process design and operation for efficient CO₂ capture under variable supply-and-demand conditions

Chemical Plants

Differentiable Hybrid Modeling for Industrial Distillation

The paper's strongest contribution is not attaching a neural network to a distillation model. It is the combination of precise error localization, a differentiable industrial-scale column solver, and a deliberately small thermodynamic correction network.

Hybrid modeling of an industrial LPG debutanizer using a differentiable first-principles distillation solver with real plant data

LLM & Probabilistic Approaches

GraphRAG for Engineering Diagrams: ChatP&ID and P&ID Retrieval

A critical note on ChatP&ID: P&IDs are better treated as structured engineering knowledge graphs than as raw images or raw XML, but the benchmark mainly validates context engineering rather than a new GraphRAG algorithm.

GraphRAG for Engineering Diagrams: ChatP&ID Enables LLM Interaction with P&IDs

Chemical Plants

Slow-Fast Degradation Inference for Chemical Plant Operation

A note on Zhao and Fink's H-CDE model for separating slow latent degradation from fast operational dynamics, read from the viewpoint of chemical plant monitoring and operation.

Disentangling slow and fast temporal dynamics in degradation inference with hierarchical differential models

LLM & Probabilistic Approaches

Tolerance Ball Acquisition for Specification-Driven Inverse Design

A critical note on Tolerance Ball acquisition: a clean probability-of-feasibility objective for specification-driven inverse design, but not a direct optimizer of diversity, boundary coverage, or global feasible-set recovery.

Range-aware Bayesian optimization for discovering diverse designs within target property windows

Graph-Represented Methods

Phenomena-Based Graphs for Chemical Process Simulation

A note on Cortés-Peña and Zavala's phenomena-based graph representation for flowsheet simulation, where nonlinear thermodynamic blocks are separated from process-wide linear material and energy balance solves.

Phenomena-based graph representations and applications to chemical process simulation

LLM & Probabilistic Approaches

BOHB and MILP for Multi-Timescale LH2 Supply Chain Design

A critical note on a BOHB-MILP framework for international liquid hydrogen supply-chain design under hourly renewable variability, weekly shipping, lead time, and sampled demand-weather scenarios.

Techno-economic analysis for design and management of international green hydrogen supply chain under uncertainty: An integrated temporal planning approach

Graph-Represented Methods

Feasible GNN Bounds for Exact Max-Cut Branch-and-Bound

A note on a Max-Cut solver that replaces repeated SDP relaxation solves with a feasibility-preserving GNN surrogate, keeping branch-and-bound correctness by constructing dual-feasible upper bounds.

Green Chemical Systems

Explainable Degradation-Aware Sizing for Off-Grid Green Hydrogen

A critical note on an off-grid PV-battery-PEM hydrogen TEA that folds PEM degradation, battery fade, replacement timing, and Sobol/XGBoost/SHAP interpretation into the sizing objective.

Explainable degradation-aware techno-economic optimization of off-grid green hydrogen production

LLM & Probabilistic Approaches

Do Transformers Need Three Projections?

A critical note on Q/K/V projection sharing in Transformer attention, where K=V preserves query-key directionality while cutting KV-cache memory in half.

Do Transformers Need Three Projections? Systematic Study of QKV Variants

Chemical Plants

TalkToAgent: Using Existing LLMs to Explain RL Controllers in Chemical Plants

A critical note on TalkToAgent, an LLM multi-agent framework that reuses existing LLMs to route natural-language questions to XRL tools for chemical process-control policies.

TalkToAgent: A multi-agent LLM Framework for natural language explanation of reinforcement learning policies

Mathematical Optimization

ORACLE: Near-Optimal Exploration as Certified Set Approximation

A note on ORACLE, which turns near-optimal energy-system exploration from point generation into an inner/outer approximation problem with a certified distance metric.

ORACLE: A rigorous metric and method to explore all near-optimal designs for energy systems

Green Chemical Systems

How Model Fidelity Changes Green Hydrogen LCOH

A critical note on how fixed-efficiency electrolyzer models and low-resolution renewable data can bias green-hydrogen LCOH estimates.

Impact of electrolyzer-model fidelity and renewable-data resolution on techno-economic assessments of green hydrogen systems

Green Chemical Systems

Degradation-Aware Economics for Renewable Green Hydrogen

A critical note on why renewable green-hydrogen TEA should treat electrolyzer degradation, replacement, and on/off operation as endogenous economic effects rather than fixed lifetime parameters.

The impact of degradation on the economics of green hydrogen

Energy Grids

Learning Data-Center Flexibility for Grid Demand Response with RMABs

A critical note on modeling data centers as restless bandit arms for grid demand response, and on where the finite-state RMAB abstraction is useful or fragile.

Robust Restless Multi-Armed Bandit for Data Center Flexibility Services Through Virtual Machine Scheduling

Mathematical Optimization

MadNCL: GPU-Friendly NCL for Degenerate Nonlinear Programs

A critical note on MadNCL, which combines Algorithm NCL, MadNLP, and GPU-friendly KKT reformulations to improve robustness on large-scale degenerate nonlinear programs.

MADNCL: a GPU implementation of algorithm NCL for large-scale, degenerate nonlinear programs

Mathematical Optimization

NLPOpt-Net: Objective-Aware Projection for Parametric Nonlinear Programs

A critical note on NLPOpt-Net, which learns a parametric NLP solution map with a neural warm start and an objective-aware differentiable projection layer.

NLPOpt-Net: A Learning Method for Nonlinear Optimization with Feasibility Guarantees

LLM & Probabilistic Approaches

LoRA and QLoRA: Low-Rank Adaptation Under Memory Constraints

LoRA reduces fine-tuning cost by learning low-rank task-specific corrections on top of frozen pretrained weights, while QLoRA adds 4-bit quantization so larger base models can be adapted under tighter GPU memory constraints.

Safe & Constrained RL

Hard Linear Constraints in Neural Decisions: Feasibility by Decision-Rule Anchoring

A critical note on enforcing input-dependent linear equality and inequality constraints in neural network outputs using a robustly feasible decision-rule anchor and minimal interpolation.

Enforcing hard linear constraints in deep learning models with decision rules

Probabilistic Heuristics & Bayesian Search

FlashAttention: Exact Attention as an IO-Aware Streaming Computation

FlashAttention is not an approximation to attention. Its core idea is to avoid materializing the N by N attention matrix in HBM by computing tiled attention in SRAM and maintaining online softmax statistics.

Stanford CME295 Transformers & LLMs | Autumn 2025 | Lecture 4 - LLM Training

Mathematical Optimization

NN-Generated Lyapunov Metrics for Fast NMPC: What Is Actually Guaranteed?

A critical note on learned Lyapunov terminal costs for NMPC, focusing on Cholesky-structured positive-definite surrogates, horizon compression, and the unresolved role of approximation error.

Learning Lyapunov terminal costs from data for complexity reduction in nonlinear model predictive control

Safe & Constrained RL

Lyapunov Projection for Continuous-Action Safe Reinforcement Learning

This note reads Lyapunov-based safe policy optimization as a practical projection bridge from finite CMDP safe policy iteration to continuous-action deep reinforcement learning, while separating exact CMDP guarantees from local approximation behavior.

Lyapunov-based Safe Policy Optimization for Continuous Control

Safe & Constrained RL

Lyapunov-Based Safe Policy Improvement for CMDPs

Lyapunov constraints turn an expected cumulative safety budget in a CMDP into local restrictions on policy improvement. This note examines the exact certificate logic and the weaker status of neural approximations.

A lyapunov-based approach to safe reinforcement learning