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GCondenser: Benchmarking Graph Condensation

arXiv.org Artificial Intelligence

Large-scale graphs are valuable for graph representation learning, yet the abundant data in these graphs hinders the efficiency of the training process. Graph condensation (GC) alleviates this issue by compressing the large graph into a significantly smaller one that still supports effective model training. Although recent research has introduced various approaches to improve the effectiveness of the condensed graph, evaluations in a more comprehensive and practical manner are not sufficiently explored. This paper proposes the first large-scale graph condensation benchmark, GCondenser, to holistically evaluate and compare mainstream GC methods. GCondenser includes a standardised GC paradigm with condensation, validation, and evaluation procedures, as well as straightforward extensions to new GC methods and datasets. Furthermore, a comprehensive study of GC methods is conducted, presenting insights into the different dimensions of condensation effectiveness.


An Experiment with the Use of ChatGPT for LCSH Subject Assignment on Electronic Theses and Dissertations

arXiv.org Artificial Intelligence

MARC and LCSH Systems Library metadata practitioners usually produce bibliographic records for library resources in the form of MARC (Machine-Readable Cataloging) records. MARC is a data format that organizes information about books and other materials in a library collection. One important part of the data is the MARC 6XX Subject Access Fields, which are used to input subject access entries and terms (e.g., topical terms, personal names, places, and time periods) covered by each book or resource. Most of these fields contain subject terms based on controlled vocabularies, one of which is the Library of Congress Subject Headings (LCSH). A key feature of the LCSH system is the application of subdivisions, allowing catalogers and indexers to construct very precise and multi-faceted subject strings by combining main headings with relevant topical, form, chronological and geographic subdivisions in a systematic way.


Advancements in Recommender Systems: A Comprehensive Analysis Based on Data, Algorithms, and Evaluation

arXiv.org Artificial Intelligence

Using 286 research papers collected from Web of Science, ScienceDirect, SpringerLink, arXiv, and Google Scholar databases, a systematic review methodology was adopted to review and summarize the current challenges and potential future developments in data, algorithms, and evaluation aspects of RSs. It was found that RSs involve five major research topics, namely algorithmic improvement, domain applications, user behavior & cognition, data processing & modeling, and social impact & ethics. Collaborative filtering and hybrid recommendation techniques are mainstream. The performance of RSs is jointly limited by four types of eight data issues, two types of twelve algorithmic issues, and two evaluation issues. Notably, data-related issues such as cold start, data sparsity, and data poisoning, algorithmic issues like interest drift, device-cloud collaboration, non-causal driven, and multitask conflicts, along with evaluation issues such as offline data leakage and multi-objective balancing, have prominent impacts. Fusing physiological signals for multimodal modeling, defending against data poisoning through user information behavior, evaluating generative recommendations via social experiments, fine-tuning pre-trained large models to schedule device-cloud resource, enhancing causal inference with deep reinforcement learning, training multi-task models based on probability distributions, using cross-temporal dataset partitioning, and evaluating recommendation objectives across the full lifecycle are feasible solutions to address the aforementioned prominent challenges and unlock the power and value of RSs.The collected literature is mainly based on major international databases, and future research will further expand upon it.


Dynamic Encoder Size Based on Data-Driven Layer-wise Pruning for Speech Recognition

arXiv.org Artificial Intelligence

In this work, we combine the benefits of both ideas and demonstrate an efficient dynamic encoder training framework. Varying-size models are often required to deploy ASR systems We leverage score-based layer-wise pruning to find the optimal under different hardware and/or application constraints such layer combination for the subnets, saving the computationally as memory and latency. To avoid redundant training and optimization expensive search required by the general supernet training efforts for individual models of different sizes, we methods [9, 10]. Furthermore, we design an efficient two-step present the dynamic encoder size approach, which jointly trains training pipeline. In Step 1, we propose two methods, Simple-multiple performant models within one supernet from scratch. Top-k and Iterative-Zero-Out, to effectively learn the associated These subnets of various sizes are layer-wise pruned from the layer importance scores in a data-driven way. In step 2, we generate supernet, and thus, enjoy full parameter sharing. By combining binary masks for all subnets and exploit the sandwich rule score-based pruning with supernet training, we propose two [6] for efficient joint training of the supernet and subnets. Additionally, novel methods, Simple-Top-k and Iterative-Zero-Out, to automatically we explore different training techniques to mitigate select the best-performing subnets in a data-driven the mutual training inference and further boost the word error manner, avoiding resource-intensive search efforts.


Explaining Spectrograms in Machine Learning: A Study on Neural Networks for Speech Classification

arXiv.org Artificial Intelligence

This study investigates discriminative patterns learned by neural networks for accurate speech classification, with a specific focus on vowel classification tasks. By examining the activations and features of neural networks for vowel classification, we gain insights into what the networks "see" in spectrograms. Through the use of class activation mapping, we identify the frequencies that contribute to vowel classification and compare these findings with linguistic knowledge. Experiments on a American English dataset of vowels showcases the explainability of neural networks and provides valuable insights into the causes of misclassifications and their characteristics when differentiating them from unvoiced speech. This study not only enhances our understanding of the underlying acoustic cues in vowel classification but also offers opportunities for improving speech recognition by bridging the gap between abstract representations in neural networks and established linguistic knowledge.


Improving Visual Place Recognition Based Robot Navigation Through Verification of Localization Estimates

arXiv.org Artificial Intelligence

Visual Place Recognition (VPR) systems often have imperfect performance, which affects robot navigation decisions. This research introduces a novel Multi-Layer Perceptron (MLP) integrity monitor for VPR which demonstrates improved performance and generalizability over the previous state-of-the-art SVM approach, removing per-environment training and reducing manual tuning requirements. We test our proposed system in extensive real-world experiments, where we also present two real-time integrity-based VPR verification methods: an instantaneous rejection method for a robot navigating to a goal zone (Experiment 1); and a historical method that takes a best, verified, match from its recent trajectory and uses an odometer to extrapolate forwards to a current position estimate (Experiment 2). Noteworthy results for Experiment 1 include a decrease in aggregate mean along-track goal error from ~9.8m to ~3.1m in missions the robot pursued to completion, and an increase in the aggregate rate of successful mission completion from ~41% to ~55%. Experiment 2 showed a decrease in aggregate mean along-track localization error from ~2.0m to ~0.5m, and an increase in the aggregate precision of localization attempts from ~97% to ~99%. Overall, our results demonstrate the practical usefulness of a VPR integrity monitor in real-world robotics to improve VPR localization and consequent navigation performance.


Arabic Automatic Story Generation with Large Language Models

arXiv.org Artificial Intelligence

Large language models (LLMs) have recently emerged as a powerful tool for a wide range of language generation tasks. Nevertheless, this progress has been slower in Arabic. In this work, we focus on the task of generating stories from LLMs. For our training, we use stories acquired through machine translation (MT) as well as GPT-4. For the MT data, we develop a careful pipeline that ensures we acquire high-quality stories. For our GPT-41 data, we introduce crafted prompts that allow us to generate data well-suited to the Arabic context in both Modern Standard Arabic (MSA) and two Arabic dialects (Egyptian and Moroccan). For example, we generate stories tailored to various Arab countries on a wide host of topics. Our manual evaluation shows that our model fine-tuned on these training datasets can generate coherent stories that adhere to our instructions. We also conduct an extensive automatic and human evaluation comparing our models against state-of-the-art proprietary and open-source models. Our datasets and models will be made publicly available at https: //github.com/UBC-NLP/arastories.


Explaining Graph Neural Networks for Node Similarity on Graphs

arXiv.org Artificial Intelligence

Similarity search is a fundamental task for exploiting information in various applications dealing with graph data, such as citation networks or knowledge graphs. While this task has been intensively approached from heuristics to graph embeddings and graph neural networks (GNNs), providing explanations for similarity has received less attention. In this work we are concerned with explainable similarity search over graphs, by investigating how GNN-based methods for computing node similarities can be augmented with explanations. Specifically, we evaluate the performance of two prominent approaches towards explanations in GNNs, based on the concepts of mutual information (MI), and gradient-based explanations (GB). We discuss their suitability and empirically validate the properties of their explanations over different popular graph benchmarks. We find that unlike MI explanations, gradient-based explanations have three desirable properties. First, they are actionable: selecting inputs depending on them results in predictable changes in similarity scores. Second, they are consistent: the effect of selecting certain inputs overlaps very little with the effect of discarding them. Third, they can be pruned significantly to obtain sparse explanations that retain the effect on similarity scores.


The Language of Weather: Social Media Reactions to Weather Accounting for Climatic and Linguistic Baselines

arXiv.org Artificial Intelligence

This study explores how different weather conditions influence public sentiment on social media, focusing on Twitter data from the UK. By considering climate and linguistic baselines, we improve the accuracy of weather-related sentiment analysis. Our findings show that emotional responses to weather are complex, influenced by combinations of weather variables and regional language differences. The results highlight the importance of context-sensitive methods for better understanding public mood in response to weather, which can enhance impact-based forecasting and risk communication in the context of climate change.


A Comprehensive Survey on the Security of Smart Grid: Challenges, Mitigations, and Future Research Opportunities

arXiv.org Artificial Intelligence

In this study, we conduct a comprehensive review of smart grid security, exploring system architectures, attack methodologies, defense strategies, and future research opportunities. We provide an in-depth analysis of various attack vectors, focusing on new attack surfaces introduced by advanced components in smart grids. The review particularly includes an extensive analysis of coordinated attacks that incorporate multiple attack strategies and exploit vulnerabilities across various smart grid components to increase their adverse impact, demonstrating the complexity and potential severity of these threats. Following this, we examine innovative detection and mitigation strategies, including game theory, graph theory, blockchain, and machine learning, discussing their advancements in counteracting evolving threats and associated research challenges. In particular, our review covers a thorough examination of widely used machine learning-based mitigation strategies, analyzing their applications and research challenges spanning across supervised, unsupervised, semi-supervised, ensemble, and reinforcement learning. Further, we outline future research directions and explore new techniques and concerns. We first discuss the research opportunities for existing and emerging strategies, and then explore the potential role of new techniques, such as large language models (LLMs), and the emerging threat of adversarial machine learning in the future of smart grid security.