pwc-archive/papers-with-abstracts huggingface dataset:
A Novel Multi-Objective Evolutionary Algorithm for Counterfactual Generation
Authors: Gabriel Doyle-Finch, Alex A. Freitas
Date: 2025-02-03 00:00:00
Tasks: counterfactual, Counterfactual Explanation

Machine learning algorithms that learn black-box predictive models (which cannot be directly interpreted) are increasingly used to make predictions affecting the lives of people. It is important that users understand the predictions of such models, particularly when the model outputs a negative prediction for the user (e.g. denying a loan). Counterfactual explanations provide users with guidance on how to change some of their characteristics to receive a different, positive classification by a predictive model. For example, if a predictive model rejected a loan application from a user, a counterfactual explanation might state: If your salary was {\pounds}50,000 (rather than your current {\pounds}35,000), then your loan would be approved. This paper proposes two novel contributions: (a) a novel multi-objective Evolutionary Algorithm (EA) for counterfactual generation based on lexicographic optimisation, rather than the more popular Pareto dominance approach; and (b) an extension to the definition of the objective of validity for a counterfactual, based on measuring the resilience of a counterfactual to violations of monotonicity constraints which are intuitively expected by users; e.g., intuitively, the probability of a loan application to be approved would monotonically increase with an increase in the salary of the applicant. Experiments involving 15 experimental settings (3 types of black box models times 5 datasets) have shown that the proposed lexicographic optimisation-based EA is very competitive with an existing Pareto dominance-based EA; and the proposed extension of the validity objective has led to a substantial increase in the validity of the counterfactuals generated by the proposed EA.
A Hybrid Swarm Intelligence Approach for Optimizing Multimodal Large Language Models Deployment in Edge-Cloud-based Federated Learning Environments
Authors: Gaith Rjouba, Hanae Elmekki, Saidul Islam, Jamal Bentahar, Rachida Dssouli
Date: 2025-02-04 00:00:00
Tasks: Cloud Computing, Federated Learning

The combination of Federated Learning (FL), Multimodal Large Language Models (MLLMs), and edge-cloud computing enables distributed and real- time data processing while preserving privacy across edge devices and cloud infrastructure. However, the deployment of MLLMs in FL environments with resource-constrained edge devices presents significant challenges, in- cluding resource management, communication overhead, and non-IID data. To address these challenges, we propose a novel hybrid framework wherein MLLMs are deployed on edge devices equipped with sufficient resources and battery life, while the majority of training occurs in the cloud. To identify suitable edge devices for deployment, we employ Particle Swarm Optimiza- tion (PSO), and Ant Colony Optimization (ACO) is utilized to optimize the transmission of model updates between edge and cloud nodes. This proposed swarm intelligence-based framework aims to enhance the efficiency of MLLM training by conducting extensive training in the cloud and fine-tuning at the edge, thereby reducing energy consumption and communication costs. Our experimental results show that the proposed method significantly improves system performance, achieving an accuracy of 92%, reducing communica- tion cost by 30%, and enhancing client participation compared to traditional FL methods. These results make the proposed approach highly suitable for large-scale edge-cloud computing systems.
DRiVE: Dynamic Recognition in VEhicles using snnTorch
Authors: Heerak Vora, Param Pathak, Parul Bakaraniya
Date: 2025-02-04 00:00:00
Tasks: vehicle detection

Spiking Neural Networks (SNNs) mimic biological brain activity, processing data efficiently through an event-driven design, wherein the neurons activate only when inputs exceed specific thresholds. Their ability to track voltage changes over time via membrane potential dynamics helps retain temporal information. This study combines SNNs with PyTorch's adaptable framework, snnTorch, to test their potential for image-based tasks. We introduce DRiVE, a vehicle detection model that uses spiking neuron dynamics to classify images, achieving 94.8% accuracy and a near-perfect 0.99 AUC score. These results highlight DRiVE's ability to distinguish vehicle classes effectively, challenging the notion that SNNs are limited to temporal data. As interest grows in energy-efficient neural models, DRiVE's success emphasizes the need to refine SNN optimization for visual tasks. This work encourages broader exploration of SNNs in scenarios where conventional networks struggle, particularly for real-world applications requiring both precision and efficiency.
DA-LIF: Dual Adaptive Leaky Integrate-and-Fire Model for Deep Spiking Neural Networks
Authors: Tianqing Zhang, Kairong Yu, Jian Zhang, Hongwei Wang
Date: 2025-02-05 00:00:00

Spiking Neural Networks (SNNs) are valued for their ability to process spatio-temporal information efficiently, offering biological plausibility, low energy consumption, and compatibility with neuromorphic hardware. However, the commonly used Leaky Integrate-and-Fire (LIF) model overlooks neuron heterogeneity and independently processes spatial and temporal information, limiting the expressive power of SNNs. In this paper, we propose the Dual Adaptive Leaky Integrate-and-Fire (DA-LIF) model, which introduces spatial and temporal tuning with independently learnable decays. Evaluations on both static (CIFAR10/100, ImageNet) and neuromorphic datasets (CIFAR10-DVS, DVS128 Gesture) demonstrate superior accuracy with fewer timesteps compared to state-of-the-art methods. Importantly, DA-LIF achieves these improvements with minimal additional parameters, maintaining low energy consumption. Extensive ablation studies further highlight the robustness and effectiveness of the DA-LIF model.
Neural Genetic Search in Discrete Spaces
Authors: Hyeonah Kim, Sanghyeok Choi, Jiwoo Son, Jinkyoo Park, Changhyun Kwon
Date: 2025-02-09 00:00:00

Effective search methods are crucial for improving the performance of deep generative models at test time. In this paper, we introduce a novel test-time search method, Neural Genetic Search (NGS), which incorporates the evolutionary mechanism of genetic algorithms into the generation procedure of deep models. The core idea behind NGS is its crossover, which is defined as parent-conditioned generation using trained generative models. This approach offers a versatile and easy-to-implement search algorithm for deep generative models. We demonstrate the effectiveness and flexibility of NGS through experiments across three distinct domains: routing problems, adversarial prompt generation for language models, and molecular design.
MERGE$^3$: Efficient Evolutionary Merging on Consumer-grade GPUs
Authors: Tommaso Mencattini, Adrian Robert Minut, Donato Crisostomi, Andrea Santilli, Emanuele Rodolà
Date: 2025-02-09 00:00:00
Tasks: GPU

Evolutionary model merging enables the creation of high-performing multi-task models but remains computationally prohibitive for consumer hardware. We introduce MERGE$^3$, an efficient framework that makes evolutionary merging feasible on a single GPU by reducing fitness computation costs 50$\times$ while preserving performance. MERGE$^3$ achieves this by Extracting a reduced dataset for evaluation, Estimating model abilities using Item Response Theory (IRT), and Evolving optimal merges via IRT-based performance estimators. Our method enables state-of-the-art multilingual and cross-lingual merging, transferring knowledge across languages with significantly lower computational overhead. We provide theoretical guarantees and an open-source library, democratizing high-quality model merging.
MetaDE: Evolving Differential Evolution by Differential Evolution
Authors: Minyang Chen, Chenchen Feng, and Ran Cheng
Date: 2025-02-13 00:00:00
Tasks: Computational Efficiency, GPU, Hyperparameter Optimization

As a cornerstone in the Evolutionary Computation (EC) domain, Differential Evolution (DE) is known for its simplicity and effectiveness in handling challenging black-box optimization problems. While the advantages of DE are well-recognized, achieving peak performance heavily depends on its hyperparameters such as the mutation factor, crossover probability, and the selection of specific DE strategies. Traditional approaches to this hyperparameter dilemma have leaned towards parameter tuning or adaptive mechanisms. However, identifying the optimal settings tailored for specific problems remains a persistent challenge. In response, we introduce MetaDE, an approach that evolves DE's intrinsic hyperparameters and strategies using DE itself at a meta-level. A pivotal aspect of MetaDE is a specialized parameterization technique, which endows it with the capability to dynamically modify DE's parameters and strategies throughout the evolutionary process. To augment computational efficiency, MetaDE incorporates a design that leverages parallel processing through a GPU-accelerated computing framework. Within such a framework, DE is not just a solver but also an optimizer for its own configurations, thus streamlining the process of hyperparameter optimization and problem-solving into a cohesive and automated workflow. Extensive evaluations on the CEC2022 benchmark suite demonstrate MetaDE's promising performance. Moreover, when applied to robot control via evolutionary reinforcement learning, MetaDE also demonstrates promising performance. The source code of MetaDE is publicly accessible at: https://github.com/EMI-Group/metade.
METAFOR: A Hybrid Metaheuristics Software Framework for Single-Objective Continuous Optimization Problems
Authors: Christian Camacho-Villalón, Marco Dorigo, Thomas Stützle
Date: 2025-02-16 00:00:00

Hybrid metaheuristics are powerful techniques for solving difficult optimization problems that exploit the strengths of different approaches in a single implementation. For algorithm designers, however, creating hybrid metaheuristic implementations has become increasingly challenging due to the vast number of design options available in the literature and the fact that they often rely on their knowledge and intuition to come up with new algorithm designs. In this paper, we propose a modular metaheuristic software framework, called METAFOR, that can be coupled with an automatic algorithm configuration tool to automatically design hybrid metaheuristics. METAFOR is specifically designed to hybridize Particle Swarm Optimization, Differential Evolution and Covariance Matrix Adaptation-Evolution Strategy, and includes a local search module that allows their execution to be interleaved with a subordinate local search. We use the configuration tool irace to automatically generate 17 different metaheuristic implementations and evaluate their performance on a diverse set of continuous optimization problems. Our results show that, across all the considered problem classes, automatically generated hybrid implementations are able to outperform configured single-approach implementations, while these latter offer advantages on specific classes of functions. We provide useful insights on the type of hybridization that works best for specific problem classes, the algorithm components that contribute to the performance of the algorithms, and the advantages and disadvantages of two well-known instance separation strategies, creating stratified training set using a fix percentage and leave-one-class-out cross-validation.
Neural Interpretable Reasoning
Authors: Pietro Barbiero, Giuseppe Marra, Gabriele Ciravegna, David Debot, Francesco De Santis, Michelangelo Diligenti, Mateo Espinosa Zarlenga, Francesco Giannini
Date: 2025-02-17 00:00:00

We formalize a novel modeling framework for achieving interpretability in deep learning, anchored in the principle of inference equivariance. While the direct verification of interpretability scales exponentially with the number of variables of the system, we show that this complexity can be mitigated by treating interpretability as a Markovian property and employing neural re-parametrization techniques. Building on these insights, we propose a new modeling paradigm -- neural generation and interpretable execution -- that enables scalable verification of equivariance. This paradigm provides a general approach for designing Neural Interpretable Reasoners that are not only expressive but also transparent.
Batch-Adaptive Annotations for Causal Inference with Complex-Embedded Outcomes
Authors: Ezinne Nwankwo, Lauri Goldkind, Angela Zhou
Date: 2025-02-14 00:00:00
Tasks: Causal Inference, Imputation

Estimating the causal effects of an intervention on outcomes is crucial. But often in domains such as healthcare and social services, this critical information about outcomes is documented by unstructured text, e.g. clinical notes in healthcare or case notes in social services. For example, street outreach to homeless populations is a common social services intervention, with ambiguous and hard-to-measure outcomes. Outreach workers compile case note records which are informative of outcomes. Although experts can succinctly extract relevant information from such unstructured case notes, it is costly or infeasible to do so for an entire corpus, which can span millions of notes. Recent advances in large language models (LLMs) enable scalable but potentially inaccurate annotation of unstructured text data. We leverage the decision of which datapoints should receive expert annotation vs. noisy imputation under budget constraints in a "design-based" estimator combining limited expert and plentiful noisy imputation data via \textit{causal inference with missing outcomes}. We develop a two-stage adaptive algorithm that optimizes the expert annotation probabilities, estimating the ATE with optimal asymptotic variance. We demonstrate how expert labels and LLM annotations can be combined strategically, efficiently and responsibly in a causal estimator. We run experiments on simulated data and two real-world datasets, including one on street outreach, to show the versatility of our proposed method.
Dynamic Influence Tracker: Measuring Time-Varying Sample Influence During Training
Authors: Jie Xu, Zihan Wu
Date: 2025-02-15 00:00:00

Existing methods for measuring training sample influence on models only provide static, overall measurements, overlooking how sample influence changes during training. We propose Dynamic Influence Tracker (DIT), which captures the time-varying sample influence across arbitrary time windows during training. DIT offers three key insights: 1) Samples show different time-varying influence patterns, with some samples important in the early training stage while others become important later. 2) Sample influences show a weak correlation between early and late stages, demonstrating that the model undergoes distinct learning phases with shifting priorities. 3) Analyzing influence during the convergence period provides more efficient and accurate detection of corrupted samples than full-training analysis. Supported by theoretical guarantees without assuming loss convexity or model convergence, DIT significantly outperforms existing methods, achieving up to 0.99 correlation with ground truth and above 98\% accuracy in detecting corrupted samples in complex architectures.
Robust High-Dimensional Mean Estimation With Low Data Size, an Empirical Study
Authors: Cullen Anderson, Jeff M. Phillips
Date: 2025-02-17 00:00:00

Robust statistics aims to compute quantities to represent data where a fraction of it may be arbitrarily corrupted. The most essential statistic is the mean, and in recent years, there has been a flurry of theoretical advancement for efficiently estimating the mean in high dimensions on corrupted data. While several algorithms have been proposed that achieve near-optimal error, they all rely on large data size requirements as a function of dimension. In this paper, we perform an extensive experimentation over various mean estimation techniques where data size might not meet this requirement due to the high-dimensional setting.
All Models Are Miscalibrated, But Some Less So: Comparing Calibration with Conditional Mean Operators
Authors: Peter Moskvichev, Dino Sejdinovic
Date: 2025-02-17 00:00:00
Tasks: All

When working in a high-risk setting, having well calibrated probabilistic predictive models is a crucial requirement. However, estimators for calibration error are not always able to correctly distinguish which model is better calibrated. We propose the \emph{conditional kernel calibration error} (CKCE) which is based on the Hilbert-Schmidt norm of the difference between conditional mean operators. By working directly with the definition of strong calibration as the distance between conditional distributions, which we represent by their embeddings in reproducing kernel Hilbert spaces, the CKCE is less sensitive to the marginal distribution of predictive models. This makes it more effective for relative comparisons than previously proposed calibration metrics. Our experiments, using both synthetic and real data, show that CKCE provides a more consistent ranking of models by their calibration error and is more robust against distribution shift.
Distributional Autoencoders Know the Score
Authors: Andrej Leban
Date: 2025-02-17 00:00:00

This work presents novel and desirable properties of a recently introduced class of autoencoders - the Distributional Principal Autoencoder (DPA) - which combines distributionally correct reconstruction with principal components-like interpretability of the encodings. First, we show formally that the level sets of the encoder orient themselves exactly with regard to the score of the data distribution. This both explains the method's often remarkable performance in disentangling the factors of variation of the data, as well as opens up possibilities of recovering its distribution while having access to samples only. In settings where the score itself has physical meaning - such as when the data obeys the Boltzmann distribution - we demonstrate that the method can recover scientifically important quantities such as the minimum free energy path. Second, we prove that if the data lies on a manifold that can be approximated by the encoder, the optimal encoder's components beyond the dimension of the manifold will carry absolutely no additional information about the data distribution. This promises potentially new ways of determining the number of relevant dimensions of the data. The results thus demonstrate that the DPA elegantly combines two often disparate goals of unsupervised learning: the learning of the data distribution and the learning of the intrinsic data dimensionality.
Deep Subspace Learning for Surface Anomaly Classification Based on 3D Point Cloud Data
Authors: Xuanming Cao, Chengyu Tao, Juan Du
Date: 2025-02-17 00:00:00
Tasks: Anomaly Classification, Classification, Fault Diagnosis

Surface anomaly classification is critical for manufacturing system fault diagnosis and quality control. However, the following challenges always hinder accurate anomaly classification in practice: (i) Anomaly patterns exhibit intra-class variation and inter-class similarity, presenting challenges in the accurate classification of each sample. (ii) Despite the predefined classes, new types of anomalies can occur during production that require to be detected accurately. (iii) Anomalous data is rare in manufacturing processes, leading to limited data for model learning. To tackle the above challenges simultaneously, this paper proposes a novel deep subspace learning-based 3D anomaly classification model. Specifically, starting from a lightweight encoder to extract the latent representations, we model each class as a subspace to account for the intra-class variation, while promoting distinct subspaces of different classes to tackle the inter-class similarity. Moreover, the explicit modeling of subspaces offers the capability to detect out-of-distribution samples, i.e., new types of anomalies, and the regularization effect with much fewer learnable parameters of our proposed subspace classifier, compared to the popular Multi-Layer Perceptions (MLPs). Extensive numerical experiments demonstrate our method achieves better anomaly classification results than benchmark methods, and can effectively identify the new types of anomalies.
JoLT: Joint Probabilistic Predictions on Tabular Data Using LLMs
Authors: Aliaksandra Shysheya, John Bronskill, James Requeima, Shoaib Ahmed Siddiqui, Javier Gonzalez, David Duvenaud, Richard E. Turner
Date: 2025-02-17 00:00:00
Tasks: Imputation, In-Context Learning, tabular-classification

We introduce a simple method for probabilistic predictions on tabular data based on Large Language Models (LLMs) called JoLT (Joint LLM Process for Tabular data). JoLT uses the in-context learning capabilities of LLMs to define joint distributions over tabular data conditioned on user-specified side information about the problem, exploiting the vast repository of latent problem-relevant knowledge encoded in LLMs. JoLT defines joint distributions for multiple target variables with potentially heterogeneous data types without any data conversion, data preprocessing, special handling of missing data, or model training, making it accessible and efficient for practitioners. Our experiments show that JoLT outperforms competitive methods on low-shot single-target and multi-target tabular classification and regression tasks. Furthermore, we show that JoLT can automatically handle missing data and perform data imputation by leveraging textual side information. We argue that due to its simplicity and generality, JoLT is an effective approach for a wide variety of real prediction problems.
Neural Guided Diffusion Bridges
Authors: Gefan Yang, Frank van der Meulen, Stefan Sommer
Date: 2025-02-17 00:00:00

We propose a novel method for simulating conditioned diffusion processes (diffusion bridges) in Euclidean spaces. By training a neural network to approximate bridge dynamics, our approach eliminates the need for computationally intensive Markov Chain Monte Carlo (MCMC) methods or reverse-process modeling. Compared to existing methods, it offers greater robustness across various diffusion specifications and conditioning scenarios. This applies in particular to rare events and multimodal distributions, which pose challenges for score-learning- and MCMC-based approaches. We propose a flexible variational family for approximating the diffusion bridge path measure which is partially specified by a neural network. Once trained, it enables efficient independent sampling at a cost comparable to sampling the unconditioned (forward) process.
Refined PAC-Bayes Bounds for Offline Bandits
Authors: Amaury Gouverneur, Tobias J. Oechtering, Mikael Skoglund
Date: 2025-02-17 00:00:00

In this paper, we present refined probabilistic bounds on empirical reward estimates for off-policy learning in bandit problems. We build on the PAC-Bayesian bounds from Seldin et al. (2010) and improve on their results using a new parameter optimization approach introduced by Rodr\'iguez et al. (2024). This technique is based on a discretization of the space of possible events to optimize the "in probability" parameter. We provide two parameter-free PAC-Bayes bounds, one based on Hoeffding-Azuma's inequality and the other based on Bernstein's inequality. We prove that our bounds are almost optimal as they recover the same rate as would be obtained by setting the "in probability" parameter after the realization of the data.