Performance Analysis
Reviews: Precision-Recall Balanced Topic Modelling
Originality * This paper's main contribution of recall-precision balanced topic model is quite original, as no other topic model (AFAIK) tries to balance recall and precision, even though those are widely used and sensible metrics. However, I don't think the authors do enough; just saying that the sparse topic models are evaluated only from the perspective of maximizing recall does not automatically mean that they would do poorly on the precision dimension. I would have liked to see an empirical comparison with a sparse topic model, especially given that there are more advanced sparse models, such as Zhang, et al WWW2013. Quality * The experiments are done well, comparing the three models using a variety of metrics including recall/precision (KL based and conventional), topic coherence, adjusted rand index on classification, and topic entropy. Some of the non-conventional metrics are explained well.
Reviews: Likelihood Ratios for Out-of-Distribution Detection
The authors were motivated to solve the problem of bacterial identification in the presence of out-of-distribution (OOD) examples: when a classifer is trained on known bacterial classes and deployed in the real world, it may erroneously classify yet unknown bacterial strains by assigning them to one of the exisiting classes with high confidence. Methods for OOD detection try to address this problem. The authors propose a novel statistic to identify OOD examples: Their method is based on taking the log-likelihood ratio (LLR) between a model trained on in-distribution data and a background model. For both models, autoregressive models are used -- the background model is trained on perturbed in-distribution data (where the amount of perturbation is a hyper-parameter that needs to be tuned). Combined with the assumption that the likelihood factorises into semantic and background contributions, the statistic can be approximated as the difference in log-likelihoods under both models, effectively focusing on the semantic components only.
Longitudinal Missing Data Imputation for Predicting Disability Stage of Patients with Multiple Sclerosis
Vazifehdan, Mahin, Bosoni, Pietro, Pala, Daniele, Tavazzi, Eleonora, Bergamaschi, Roberto, Bellazzi, Riccardo, Dagliati, Arianna
Multiple Sclerosis (MS) is a chronic disease characterized by progressive or alternate impairment of neurological functions (motor, sensory, visual, and cognitive). Predicting disease progression with a probabilistic and time-dependent approach might help in suggesting interventions that can delay the progression of the disease. However, extracting informative knowledge from irregularly collected longitudinal data is difficult, and missing data pose significant challenges. MS progression is measured through the Expanded Disability Status Scale (EDSS), which quantifies and monitors disability in MS over time. EDSS assesses impairment in eight functional systems (FS). Frequently, only the EDSS score assigned by clinicians is reported, while FS sub-scores are missing. Imputing these scores might be useful, especially to stratify patients according to their phenotype assessed over the disease progression. This study aimed at i) exploring different methodologies for imputing missing FS sub-scores, and ii) predicting the EDSS score using complete clinical data. Results show that Exponential Weighted Moving Average achieved the lowest error rate in the missing data imputation task; furthermore, the combination of Classification and Regression Trees for the imputation and SVM for the prediction task obtained the best accuracy.
Unveiling Zero-Space Detection: A Novel Framework for Autonomous Ransomware Identification in High-Velocity Environments
Svet, Lafedi, Brightwell, Arthur, Wildflower, Augustus, Marshwood, Cecily
Modern cybersecurity landscapes increasingly demand sophisticated detection frameworks capable of identifying evolving threats with precision and adaptability. The proposed Zero-Space Detection framework introduces a novel approach that dynamically identifies latent behavioral patterns through unsupervised clustering and advanced deep learning techniques. Designed to address the limitations of signature-based and heuristic methods, it operates effectively in high-velocity environments by integrating multi-phase filtering and ensemble learning for refined decision-making. Experimental evaluation reveals high detection rates across diverse ransomware families, including LockBit, Conti, REvil, and BlackMatter, while maintaining low false positive rates and scalable performance. Computational overhead remains minimal, with average processing times ensuring compatibility with real-time systems even under peak operational loads. The framework demonstrates resilience against adversarial strategies such as obfuscation and encryption speed variability, which frequently challenge conventional detection systems. Analysis across multiple data sources highlights its versatility in handling diverse file types and operational contexts. Comprehensive metrics, including detection probability, latency, and resource efficiency, validate its efficacy under real-world conditions. Through its modular architecture, the framework achieves seamless integration with existing cybersecurity infrastructures without significant reconfiguration. The results demonstrate its robustness and scalability, offering a transformative paradigm for ransomware identification in dynamic and resource-constrained environments.
Anomaly Detection in Double-entry Bookkeeping Data by Federated Learning System with Non-model Sharing Approach
Mashiko, Sota, Kawamata, Yuji, Nakayama, Tomoru, Sakurai, Tetsuya, Okada, Yukihiko
Anomaly detection is crucial in financial auditing and effective detection often requires obtaining large volumes of data from multiple organizations. However, confidentiality concerns hinder data sharing among audit firms. Although the federated learning (FL)-based approach, FedAvg, has been proposed to address this challenge, its use of mutiple communication rounds increases its overhead, limiting its practicality. In this study, we propose a novel framework employing Data Collaboration (DC) analysis -- a non-model share-type FL method -- to streamline model training into a single communication round. Our method first encodes journal entry data via dimensionality reduction to obtain secure intermediate representations, then transforms them into collaboration representations for building an autoencoder that detects anomalies. We evaluate our approach on a synthetic dataset and real journal entry data from multiple organizations. The results show that our method not only outperforms single-organization baselines but also exceeds FedAvg in non-i.i.d. experiments on real journal entry data that closely mirror real-world conditions. By preserving data confidentiality and reducing iterative communication, this study addresses a key auditing challenge -- ensuring data confidentiality while integrating knowledge from multiple audit firms. Our findings represent a significant advance in artificial intelligence-driven auditing and underscore the potential of FL methods in high-security domains.
Enhancing Multi-Attribute Fairness in Healthcare Predictive Modeling
Wang, Xiaoyang, Yang, Christopher C.
Artificial intelligence (AI) systems in healthcare have demonstrated remarkable potential to improve patient outcomes. However, if not designed with fairness in mind, they also carry the risks of perpetuating or exacerbating existing health disparities. Although numerous fairness-enhancing techniques have been proposed, most focus on a single sensitive attribute and neglect the broader impact that optimizing fairness for one attribute may have on the fairness of other sensitive attributes. In this work, we introduce a novel approach to multi-attribute fairness optimization in healthcare AI, tackling fairness concerns across multiple demographic attributes concurrently. Our method follows a two-phase approach: initially optimizing for predictive performance, followed by fine-tuning to achieve fairness across multiple sensitive attributes. We develop our proposed method using two strategies, sequential and simultaneous. Our results show a significant reduction in Equalized Odds Disparity (EOD) for multiple attributes, while maintaining high predictive accuracy. Notably, we demonstrate that single-attribute fairness methods can inadvertently increase disparities in non-targeted attributes whereas simultaneous multi-attribute optimization achieves more balanced fairness improvements across all attributes. These findings highlight the importance of comprehensive fairness strategies in healthcare AI and offer promising directions for future research in this critical area.
CAND: Cross-Domain Ambiguity Inference for Early Detecting Nuanced Illness Deterioration
Ting, Lo Pang-Yun, Tan, Zhen, Chen, Hong-Pei, Li, Cheng-Te, Chen, Po-Lin, Chuang, Kun-Ta, Liu, Huan
Early detection of patient deterioration is essential for timely treatment, with vital signs like heart rates being key health indicators. Existing methods tend to solely analyze vital sign waveforms, ignoring transition relationships of waveforms within each vital sign and the correlation strengths among various vital signs. Such studies often overlook nuanced illness deterioration, which is the early sign of worsening health but is difficult to detect. In this paper, we introduce CAND, a novel method that organizes the transition relationships and the correlations within and among vital signs as domain-specific and cross-domain knowledge. CAND jointly models these knowledge in a unified representation space, considerably enhancing the early detection of nuanced illness deterioration. In addition, CAND integrates a Bayesian inference method that utilizes augmented knowledge from domain-specific and cross-domain knowledge to address the ambiguities in correlation strengths. With this architecture, the correlation strengths can be effectively inferred to guide joint modeling and enhance representations of vital signs. This allows a more holistic and accurate interpretation of patient health. Our experiments on a real-world ICU dataset demonstrate that CAND significantly outperforms existing methods in both effectiveness and earliness in detecting nuanced illness deterioration. Moreover, we conduct a case study for the interpretable detection process to showcase the practicality of CAND.
Contrastive Language-Structure Pre-training Driven by Materials Science Literature
Suzuki, Yuta, Taniai, Tatsunori, Igarashi, Ryo, Saito, Kotaro, Chiba, Naoya, Ushiku, Yoshitaka, Ono, Kanta
Understanding structure-property relationships is an essential yet challenging aspect of materials discovery and development. To facilitate this process, recent studies in materials informatics have sought latent embedding spaces of crystal structures to capture their similarities based on properties and functionalities. However, abstract feature-based embedding spaces are human-unfriendly and prevent intuitive and efficient exploration of the vast materials space. Here we introduce Contrastive Language--Structure Pre-training (CLaSP), a learning paradigm for constructing crossmodal embedding spaces between crystal structures and texts. CLaSP aims to achieve material embeddings that 1) capture property- and functionality-related similarities between crystal structures and 2) allow intuitive retrieval of materials via user-provided description texts as queries. To compensate for the lack of sufficient datasets linking crystal structures with textual descriptions, CLaSP leverages a dataset of over 400,000 published crystal structures and corresponding publication records, including paper titles and abstracts, for training. We demonstrate the effectiveness of CLaSP through text-based crystal structure screening and embedding space visualization.
REX: Causal Discovery based on Machine Learning and Explainability techniques
Renero, Jesus, Ochoa, Idoia, Maestre, Roberto
Causal discovery --the process of identifying cause-and-effect relationships from observational data-- is a pivotal challenge in artificial intelligence (AI) and machine learning. Unveiling causal structures enables robust predictions, facilitates counterfactual reasoning, and enhances decision-making processes in complex systems [1]. Traditional methods for causal discovery often rely on statistical tests for independence and structural equation modeling, which may not scale efficiently with high-dimensional data or effectively capture intricate non-linear relationships [2, 3]. In recent years, machine learning models, particularly deep learning architectures, have achieved remarkable success in predictive tasks. However, these models are typically considered "black boxes" due to their lack of interpretability. This opacity has led to a growing interest in explainable AI (XAI) techniques, with Shapley values emerging as a prominent method for interpreting model predictions [4]. Shapley values, grounded in cooperative game theory, provide a principled approach to attributing the contribution of each feature to the output of a model by quantifying the average marginal contribution of a feature across all possible subsets of features [5]. While Shapley values offer valuable insights into feature importance within a model's predictive framework, the link between feature importance and causal influence is non-trivial.
Forecasting of Bitcoin Prices Using Hashrate Features: Wavelet and Deep Stacking Approach
Mousa, Ramin, Afrookhteh, Meysam, Khaloo, Hooman, Bengari, Amir Ali, Heidary, Gholamreza
Digital currencies have become popular in the last decade due to their non-dependency and decentralized nature. The price of these currencies has seen a lot of fluctuations at times, which has increased the need for prediction. As their most popular, Bitcoin(BTC) has become a research hotspot. The main challenge and trend of digital currencies, especially BTC, is price fluctuations, which require studying the basic price prediction model. This research presents a classification and regression model based on stack deep learning that uses a wavelet to remove noise to predict movements and prices of BTC at different time intervals. The proposed model based on the stacking technique uses models based on deep learning, especially neural networks and transformers, for one, seven, thirty and ninety-day forecasting. Three feature selection models, Chi2, RFE and Embedded, were also applied to the data in the pre-processing stage. The classification model achieved 63\% accuracy for predicting the next day and 64\%, 67\% and 82\% for predicting the seventh, thirty and ninety days, respectively. For daily price forecasting, the percentage error was reduced to 0.58, while the error ranged from 2.72\% to 2.85\% for seven- to ninety-day horizons. These results show that the proposed model performed better than other models in the literature.