Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that require integrated, semantically structured representations of chemical identity, classification, and properties to support integrated contaminant monitoring and analysis. This work presents the CompTox ontology, an expert-guided ontology describing commonly analyzed PFAS and designed to support PFAS data integration and querying. The ontology organizes PFAS hierarchically according to key physicochemical characteristics and incorporates authoritative identifiers and properties from EPA's CompTox Chemicals Dashboard. Individual PFAS are annotated with core chemical identifiers, including DTXSID, CASRN, InChIKey, and SMILES; with physicochemical attributes such as molecular mass, carbon chain length, and functional group information; and with observed or predicted environmental fate and transport and toxicological information. The ontology was constructed using the Knowledge Acquisition and Representation Methodology (KNARM), employing a template-driven workflow implemented with the ROBOT tool to generate an OWL-formatted ontology. An expert-guided hierarchy captures major PFAS classes, including fluorotelomers, perfluoroalkyl acids (both Perfluoroalkyl Carboxylic and Sulfonic Acids), and perfluoroalkyl ether acids. Human-readable IRIs and SKOS alternative labels enhance usability. The ontology helps facilitate integrated querying and analysis of PFAS contamination within the SAWGraph knowledge graphs but also serves as a flexible and extensible framework for unified chemical identification and classification.
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Off-policy evaluation (OPE) is widely used to compare contextual bandit policies in recommender systems. While there a lot of recent methodological developments, suggesting novel OPE schemes, they are typically validated in the synthetic environments, which not necessarily possess the structure of the real-world datasets. In this paper, we consider the inverse propensity score (IPS) method and its modifications, and study how empirical conclusions inferred from the data depend on evaluation pipelines. We show, that even in the synthetic environments, rankings of different estimators are sensitive to random seeds, log generators, and sample size. Using the popular benchmark, the Open Bandit Dataset, we analyze logging behavior and data characteristics that may violate the i.i.d. assumptions of the log generation.
Large Language Models (LLMs) have shown significant potential for improving recommendation systems through their inherent reasoning capabilities and extensive knowledge base. Yet, existing studies predominantly address warm-start scenarios with abundant user-item interaction data, leaving the more challenging cold-start scenarios, where sparse interactions hinder traditional collaborative filtering methods, underexplored. To address this limitation, we propose novel reasoning strategies designed for cold-start item recommendations within the Netflix domain. Our method utilizes the advanced reasoning capabilities of LLMs to effectively infer user preferences, particularly for newly introduced or rarely interacted items. We systematically evaluate supervised fine-tuning, reinforcement learning-based fine-tuning, and hybrid approaches that combine both methods to optimize recommendation performance. Extensive experiments on real-world data demonstrate significant improvements in both methodological efficacy and practical performance in cold-start recommendation contexts. Remarkably, our reasoning-based fine-tuned models outperform Netflix's production ranking model by up to 8% in certain cases.
We present BanditLP, a scalable multi-stakeholder contextual bandit framework that unifies neural Thompson Sampling (TS) for learning objective-specific outcomes with a large-scale linear program (LP) for constrained action selection at serving time. The methodology is application-agnostic, compatible with arbitrary neural architectures, and deployable at web scale, with an LP solver capable of handling billions of variables. Experiments on public benchmarks and synthetic data show consistent gains over strong baselines. We apply this approach in LinkedIn's email marketing system and demonstrate business win, illustrating the value of integrated exploration and constrained optimization in production.
Large Language Models (LLMs) enable Web-scale multilingual content analysis but face critical challenges in scaling to long-tail languages and ensuring robustness. Current research is split between two isolated trajectories: a Macro-Paradigm (system-level engineering) and a Micro-Paradigm (internal model intervention). We argue that a true Web-scale solution requires their systematic fusion, balancing large-scale data processing with fine-grained model control. We introduce the Control-Tower Framework (CTF), a novel methodology designed to systematically enhance powerful, pre-trained base models. Inspired by control-theoretic ideas, CTF transforms a base model into a controllable analysis engine via three synergistic stages: (1) Micro-enhanced pre-training that injects linguistic priors (e.g., syntax) to build a robust semantic foundation; (2) a control-inspired fine-tuning stage where a heuristic dynamic feedback loop, driven by micro-level error signals (e.g., knowledge editing loss), actively adjusts the macro-scale learning curriculum; and (3) Macro-optimized inference using Minimum Bayes Risk (MBR) decoding to enhance robustness on noisy user-generated content (UGC). Extensive experiments show that CTF surpasses the leading open-weights model, Tower+ 9B FT, by a substantial margin of +2.18 XCOMET-XXL on low-resource languages (WMT24++). Crucially, CTF unlocks large-scale cross-lingual Web mining by converting unstructured Web text into machine-analyzable assets. We evidence this with substantial gains across both document-level (on MARC) and aspect-based (on SemEval-2016) sentiment analysis tasks. Our work offers a practical pathway toward building more reliable, scalable, and controllable global information ecosystems.
Generative latent diffusion models (LDMs) have been extensively applied in various fields yet underperform in time-series prediction. Therefore, We propose the Re-Diffusion model, a latent diffusion approach that generates backbone residuals specifically tailored for time-series forecasting. The model comprises a variational autoencoder that compresses the residuals between the actual future values and the predictions from the backbone into latent space. It also includes a conditional diffusion generator to forecast the potential distribution of these residuals. Our findings reveal that this latent-space methodology particularly enhances existing backbone predictors, by effectively reducing prediction bias through an advanced estimation of complex error distributions. While previous diffusion-based models tend to struggle with long-term forecasting, Re-Diffusion integrates the strengths of diffusion methods, leading to improvements in long-term predictions. Our experimental results indicate that the Re-Diffusion model achieves a 10% promotion over state-of-art predictors, marking a significant advancement in the field of time-series forecasting.
While Large Language Models (LLMs) are increasingly deployed in Web applications such as search, dialogue, and recommendation systems, their reliance on large-scale Web data raises serious privacy concerns, particularly the risk of memorizing sensitive content. Existing Membership Inference Attacks (MIA) rely heavily on the surface form of inputs, rendering them ineffective against semantically preserved but structurally altered samples. This methodological weakness results in widespread false negatives and compromises the integrity of privacy evaluations in large-scale Web corpora. To address this limitation, we propose Adversarial Semantic Membership Inference Attack (ASMIA). ASMIA enhances MIA effectiveness by generating semantically diverse adversarial samples, extracting multi-layer attention features from the target model, and training a contrastive classifier that leverages similarity metrics and logarithmic probabilities to distinguish members from non-members. Experiments on LLMs trained with Wikipedia, a representative large-scale Web corpus, demonstrate that ASMIA significantly outperforms existing methods, highlighting the value of semantic perturbations and attention patterns in detecting training data leakage.
Phishing is a threat in which attackers masquerade as legitimate entities to steal sensitive data. While understanding the phishing ecosystem is critical for developing effective countermeasures, prior research has largely studied phishing through post-attack data, with limited examination of the attacker's perspective and how phishing campaigns are built. Critically, the Deep and Dark Web (D2Web) serves as the primary marketplace and knowledge-sharing platform where attackers acquire phishing tools (e.g., phishing kits), exchange techniques, and trade compromised credentials. Analyzing D2Web forums therefore provides unique visibility into the supply chain of phishing attacks pre-deployment, enabling proactive understanding of emerging threats and attack methodologies. This study addresses this gap through a comprehensive analysis of 394,034 posts (343,334 unique) collected from 13 D2Web forums spanning 2013 to 2025, from which 70,055 phishing-related posts are identified. We employ a LLM-based approach to efficiently extract key information, including phishing attack components (e.g., credentials, phishing pages, SMTP servers), targeted services (e.g., PayPal, Netflix), and component authors. This extracted data is mapped to a seven-stage attack scenario framework derived from empirical case studies. Our analysis reveals longitudinal trends in component availability, target service distribution, post type evolution, and the most active contributors annually, while characterizing pricing dynamics across different attack components. The results provide the first attacker-centric, macro-level longitudinal analysis of the phishing ecosystem, offering insights into how phishing infrastructure and markets have evolved over more than a decade. These findings contribute to a deeper understanding of the phishing supply chain and inform more effective detection and prevention strategies.
Owing to their unprecedented comprehension capabilities, large language models (LLMs) have become indispensable components of modern web search engines. From a technical perspective, this integration represents retrieval-augmented generation (RAG), which enhances LLMs by grounding them in external knowledge base. A prevalent technical approach in this context is graph-based RAG (G-RAG). However, current G-RAG methodologies frequently underutilize graph topology, predominantly focusing on low-order structures or pre-computed static communities. This limitation affects their effectiveness in addressing dynamic and complex queries. Thus, we propose DA-RAG, which leverages attributed community search (ACS) to dynamically extract relevant subgraphs based on the queried question. DA-RAG captures high-order graph structures, allowing for the retrieval of self-complementary knowledge. Furthermore, DA-RAG is equipped with a chunk-layer oriented graph index, which facilitates efficient multi-granularity retrieval while significantly reducing both computational and economic costs. We evaluate DA-RAG on multiple datasets, demonstrating that it outperforms existing RAG methods by up to 40% in head-to-head comparisons across four metrics while reducing index construction time and token overhead by up to 37% and 41%, respectively.
With the rapid growth of Web-based academic publications, more and more papers are being published annually, making it increasingly difficult to find relevant prior work. Citation prediction aims to automatically suggest appropriate references, helping scholars navigate the expanding scientific literature. Here we present CiteRAG, the first comprehensive retrieval-augmented generation (RAG)-integrated benchmark for evaluating large language models on academic citation prediction, featuring a multi-level retrieval strategy, specialized retrievers, and generators. Our benchmark makes four core contributions: (1) We establish two instances of the citation prediction task with different granularity. Task 1 focuses on coarse-grained list-specific citation prediction, while Task 2 targets fine-grained position-specific citation prediction. To enhance these two tasks, we build a dataset containing 7,267 instances for Task 1 and 8,541 instances for Task 2, enabling comprehensive evaluation of both retrieval and generation. (2) We construct a three-level large-scale corpus with 554k papers spanning many major subfields, using an incremental pipeline. (3) We propose a multi-level hybrid RAG approach to citation prediction, fine-tuning embedding models with contrastive learning to capture complex citation relationships, paired with specialized generation models. (4) We conduct extensive experiments across state-of-the-art language models, including closed-source APIs, open-source models, and our fine-tuned generators, demonstrating the effectiveness of our framework. Our open-source toolkit enables reproducible evaluation and focuses on academic literature, providing the first comprehensive evaluation framework for citation prediction and serving as a methodological template for other scientific domains. Our source code and data are released at https://github.com/LQgdwind/CiteRAG.
Since the first online ad in 1994, advertising has grown into a vast ecosystem delivering billions of ads daily. Advertisements are everywhere on the Web: search engines promote results, most websites display ads, some require users to accept ads as a condition for access, video streaming services fund their infrastructure through an increasing volume of ads, and much of the gaming industry has adopted ad-based revenue models. In exchange for free access to a wide range of content, web users sacrifice their privacy and pay with personal data to enable targeted marketing, a trade-off widely studied in literature. We argue that the ad ecosystem imposes an additional, overlooked, cost on web users: energy consumption. In this paper, we present a large-scale analysis of the client-side energy consumption of ads, including their associated tracking mechanisms. We design a robust methodology aimed at realistically modeling user behavior and monitoring CPU activity. Through measurements of 724,994 website visits across diverse devices, we study the energy implications of consenting to tracking and of blocking ads through browser and network-based software. We find that consent via cookie banners increases energy consumption by a median 2.57% across all websites and devices. We also show that websites relying on real-time bidding increase median energy consumption by 33.98%. Finally, although ad-blocking solutions consume energy due to their filtering processes, we observe a median reduction of 9.62% in client-side energy consumption when using uBlock Origin.
Multi-Agent Systems (MAS) offer a powerful paradigm for solving complex problems, yet their performance is critically dependent on the design of their underlying collaboration topology. As MAS become increasingly deployed in web services (e.g., search engines), designing adaptive topologies for diverse cross-domain user queries becomes essential. Current graph learning-based design methodologies often adhere to a ''one-for-one'' paradigm, where a specialized model is trained for each specific task domain. This approach suffers from poor generalization to unseen domains and fails to leverage shared structural knowledge across different tasks. To address this, we propose OFA-MAS, a one-for-all framework that generates adaptive collaboration graphs for any task described in natural language through a single universal model. Our approach integrates a Task-Aware Graph State Encoder (TAGSE) that filters task-relevant node information via sparse gating, and a Mixture-of-Experts (MoE) architecture that dynamically selects specialized sub-networks to drive node and edge prediction. We employ a three-stage training strategy: unconditional pre-training on canonical topologies for structural priors, large-scale conditional pre-training on LLM-generated datasets for task-topology mappings, and supervised fine-tuning on empirically validated graphs. Experiments across six diverse benchmarks show that OFA-MAS significantly outperforms specialized one-for-one models, generating highly adaptive MAS topologies. Code: https://github.com/Shiy-Li/OFA-MAS.
Graph Masked Autoencoders (GMAEs) have emerged as a notable self-supervised learning approach for graph-structured data. Existing GMAE models primarily focus on reconstructing node-level information, categorizing them as single-scale GMAEs. This methodology, while effective in certain contexts, tends to overlook the complex hierarchical structures inherent in many real-world graphs. For instance, molecular graphs exhibit a clear hierarchical organization in the form of the atoms-functional groups-molecules structure. Therefore, the inability of single-scale GMAE models to incorporate these hierarchical relationships often results in an inadequate capture of crucial high-level graph information, leading to a noticeable decline in performance. To address this limitation, we propose Hierarchical Graph Masked AutoEncoders (Hi-GMAE), a novel multi-scale GMAE framework designed to handle the hierarchical structures within graphs. First, Hi-GMAE constructs a multi-scale graph hierarchy through graph pooling, enabling the exploration of graph structures across different granularity levels. To ensure masking uniformity of subgraphs across these scales, we propose a novel coarse-to-fine strategy that initiates masking at the coarsest scale and progressively back-projects the mask to finer scales. Furthermore, we integrate a gradual recovery strategy with the masking process to mitigate the learning challenges posed by completely masked subgraphs. Diverging from the standard graph neural network (GNN) used in GMAE models, Hi-GMAE modifies its encoder and decoder into hierarchical structures. This entails using GNN at the finer scales for detailed local graph analysis and employing a graph transformer at coarser scales to capture global information. Such a design enables Hi-GMAE to effectively capture the multi-level information inherent in complex graph structures. Our experiments on 17 graph datasets, covering two graph learning tasks, consistently demonstrate that Hi-GMAE outperforms 29 state-of-the-art self-supervised competitors in capturing comprehensive graph information.
Conventional Federated Learning (FL) pipelines focus on the collaborative training of a global dense model across client devices. Sparsity has been increasingly adopted in FL, during or after local optimization, for a range of objectives, including reducing communication and computation costs, supporting unlearning, enhancing privacy guarantees, and improving local personalization. In this survey, we introduce a novel taxonomy of sparse FL methods that systematically organizes the existing literature according to their core objectives and methodological choices. Using this taxonomy, we analyze and categorize prior work, highlighting the underlying intuitions, technical mechanisms, benefits, and limitations of each class of approaches. Finally, we identify open challenges, expose research gaps, and extract guidance to help practitioners understand and adopt sparsity mechanisms in FL.
Most of the widely used estimators of the average treatment effect (ATE) in causal inference rely on the assumptions of unconfoundedness and overlap. Unconfoundedness requires that the observed covariates account for all correlations between the outcome and treatment. Overlap requires the existence of randomness in treatment decisions for all individuals. Nevertheless, many types of studies frequently violate unconfoundedness or overlap; for instance, observational studies with deterministic treatment decisions, popularly known as Regression Discontinuity designs, violate overlap. In this paper, we initiate the study of general conditions that enable the identification of the average treatment effect, extending beyond unconfoundedness and overlap. In particular, following the paradigm of statistical learning theory, we provide an interpretable condition that is sufficient and necessary for the identification of ATE. Moreover, this condition can be used to characterize other treatment effects, such as the average treatment effect on the treated (ATT), as well. To illustrate the utility of our condition, we present several well-studied scenarios where our condition is satisfied and, hence, we prove that ATE can be identified in regimes that prior works could not capture. For example, under mild assumptions on the data distributions, this holds for the models proposed by Tan (2006) and Rosenbaum (2002), and the Regression Discontinuity design model introduced by Thistlethwaite and Campbell (1960). For each of these scenarios, we also show that, under natural additional assumptions, ATE can be estimated from finite samples. We believe these findings open new avenues for bridging learning-theoretic insights and causal inference methodologies, particularly in observational studies with complex treatment mechanisms.
Counterfactual explanations have become an important paradigm for improving the transparency of machine learning models by showing how small input changes can alter model outputs. While substantial progress has been made in generating such explanations, their evaluation remains insufficiently standardized, particularly for systems that produce ranked outputs rather than single-label predictions. Existing evaluation protocols in recommender systems commonly focus only on whether the top-1 recommendation changes after perturbation. We argue that this practice can lead to inconsistent and misleading conclusions, as the relative ranking of explanation methods may vary with changes in the quality of the underlying model. In this work, we revisit the evaluation of counterfactual explanations from a ranking perspective. We propose extending top-1 evaluation to list-wise top-$k$ protocols that assess explanation effectiveness across multiple highly ranked outputs. Through experiments on multiple datasets, recommender architectures, and explanation methods, we show that top-$k$ evaluation substantially improves consistency and yields more reliable comparisons between competing explainers. Our findings highlight a broader methodological lesson for explainable AI: when models return ranked results, explanation quality should be assessed using ranking-aware evaluation protocols rather than top-1 criteria alone.
Graph Neural Networks (GNNs) have demonstrated remarkable proficiency in modeling data with graph structures, yet recent research reveals their susceptibility to adversarial attacks. Traditional attack methodologies, which rely on manipulating the original graph or adding links to artificially created nodes, often prove impractical in real-world settings. This paper introduces a novel adversarial scenario involving the injection of an isolated subgraph to deceive both the link recommender and the node classifier within a GNN system. Specifically, the link recommender is mislead to propose links between targeted victim nodes and the subgraph, encouraging users to unintentionally establish connections and that would degrade the node classification accuracy, thereby facilitating a successful attack. To address this, we present the LiSA framework, which employs a dual surrogate model and bi-level optimization to simultaneously meet two adversarial objectives. Extensive experiments on real-world datasets demonstrate the effectiveness of our method.
Detecting spoofing in financial trading is a critical data mining task. While traditional machine learning models focus on individual node features, graph-based methodologies have shown superior performance by integrating relational data and structure information. However, spoofing transactions often exhibit distribution shifts, making historical data less effective. Instead, certain consistent trading patterns, such as motif structures, remain robust for analysis across different distributions. Therefore, this paper introduces the Structure-Augmented Generative Graph Model (SAG^2M) to detect conspiracy spoofing through substructure frequency-augmented detection. Our approach extracts subgraph pattern frequencies among neighboring nodes using an enumeration algorithm, and encodes these motif frequencies into a structure-augmented generative framework. A temporal and heterogeneous graph generation and aggregation scheme is then applied to collect neighborhood node information, effectively uncovering conspiracy spoofing patterns. Experiments on benchmark datasets demonstrate that SAG^2M outperforms existing models in detection accuracy. Case studies further highlight its superior effectiveness in identifying complex fraudulent behaviors.
Recent research shows that conversational AI can shift voter preferences, with effects persisting for weeks. Yet frontier models exhibit a documented "persuasion-reliability tradeoff", producing hallucinated or systematically distorted election information. Despite these risks, election officials lack standardized tools to systematically evaluate AI systems before deployment. We propose CivicAudit-Bench, a stakeholder-guided auditing framework to stress-test large language models for civic hallucinations, false confidence, jurisdiction-dependent failure, and asymmetric refusals/accuracy. This framework introduces a modular, counterfactual, and severity-aware auditing methodology that integrates roll-call–based alignment modeling, entity-swap probing, and jurisdiction-conditional correctness criteria. Informed by engagement with the U.S. Election Assistance Commission, the toolkit consists of three modules: (1) PoliBias-US, a multi-indicator alignment screen combining Congressional roll-call ideology scaling with party-cue counterfactual sensitivity, persona robustness, and narrative-framing alignment; (2) HalluBias-Election, an evidence-linked benchmark that measures hallucinations, severity-weighted critical errors, and asymmetries via Entity-Swap Counterfactual Probing and a jurisdiction-safe completion criterion; and (3) Disclosure-Test, pre-registered experiments assessing whether transparency and calibrated-uncertainty disclosures reduce overreliance and attenuate persuasion without blocking legitimate civic information. CivicAudit-Bench outputs versioned audit scorecards and a coordinated white-hat disclosure workflow, advancing UN SDG~16 by strengthening democratic information integrity.
We propose the notion of statistically likely k-step reachable set in probabilistic programs, a statistically robust notion for high-probability k-step reachable program states. We design an inductive algorithm to capture this set as a symbolic representation in propositional logic for Boolean probabilistic programs. Our methodology iteratively learns a symbolic formula for the statistically likely k-step reachable set that involves (a) learning an initial symbolic candidate via decision tree learning, (b) collecting positive and negative counterexamples via forward and backward verification checks, and (c) refining the current candidate via a sequence of prune and split moves on the decision tree. We demonstrate that the statistically likely k-step reachable set can reveal interesting properties about programs by studying probabilistic programs from the literature.