Statistical Learning
Towards Modeling Data Quality and Machine Learning Model Performance
Anjum, Usman, Trentman, Chris, Caden, Elrod, Zhan, Justin
Understanding the effect of uncertainty and noise in data on machine learning models (MLM) is crucial in developing trust and measuring performance. In this paper, a new model is proposed to quantify uncertainties and noise in data on MLMs. Using the concept of signal-to-noise ratio (SNR), a new metric called deterministic-non-deterministic ratio (DDR) is proposed to formulate performance of a model. Using synthetic data in experiments, we show how accuracy can change with DDR and how we can use DDR-accuracy curves to determine performance of a model.
Post-hoc Probabilistic Vision-Language Models
Baumann, Anton, Li, Rui, Klasson, Marcus, Mentu, Santeri, Karthik, Shyamgopal, Akata, Zeynep, Solin, Arno, Trapp, Martin
Vision-language models (VLMs), such as CLIP and SigLIP, have found remarkable success in classification, retrieval, and generative tasks. For this, VLMs deterministically map images and text descriptions to a joint latent space in which their similarity is assessed using the cosine similarity. However, a deterministic mapping of inputs fails to capture uncertainties over concepts arising from domain shifts when used in downstream tasks. In this work, we propose post-hoc uncertainty estimation in VLMs that does not require additional training. Our method leverages a Bayesian posterior approximation over the last layers in VLMs and analytically quantifies uncertainties over cosine similarities. We demonstrate its effectiveness for uncertainty quantification and support set selection in active learning. Compared to baselines, we obtain improved and well-calibrated predictive uncertainties, interpretable uncertainty estimates, and sample-efficient active learning. Our results show promise for safety-critical applications of large-scale models.
MVD: A Multi-Lingual Software Vulnerability Detection Framework
Zhang, Boyu, Le, Triet H. M., Babar, M. Ali
Software vulnerabilities can result in catastrophic cyberattacks that increasingly threaten business operations. Consequently, ensuring the safety of software systems has become a paramount concern for both private and public sectors. Recent literature has witnessed increasing exploration of learning-based approaches for software vulnerability detection. However, a key limitation of these techniques is their primary focus on a single programming language, such as C/C++, which poses constraints considering the polyglot nature of modern software projects. Further, there appears to be an oversight in harnessing the synergies of vulnerability knowledge across varied languages, potentially underutilizing the full capabilities of these methods. To address the aforementioned issues, we introduce MVD - an innovative multi-lingual vulnerability detection framework. This framework acquires the ability to detect vulnerabilities across multiple languages by concurrently learning from vulnerability data of various languages, which are curated by our specialized pipeline. We also incorporate incremental learning to enable the detection capability of MVD to be extended to new languages, thus augmenting its practical utility. Extensive experiments on our curated dataset of more than 11K real-world multi-lingual vulnerabilities substantiate that our framework significantly surpasses state-of-the-art methods in multi-lingual vulnerability detection by 83.7% to 193.6% in PR-AUC. The results also demonstrate that MVD detects vulnerabilities well for new languages without compromising the detection performance of previously trained languages, even when training data for the older languages is unavailable. Overall, our findings motivate and pave the way for the prediction of multi-lingual vulnerabilities in modern software systems.
A Comprehensive Survey and Guide to Multimodal Large Language Models in Vision-Language Tasks
Liang, Chia Xin, Tian, Pu, Yin, Caitlyn Heqi, Yua, Yao, An-Hou, Wei, Ming, Li, Wang, Tianyang, Bi, Ziqian, Liu, Ming
This survey and application guide to multimodal large language models(MLLMs) explores the rapidly developing field of MLLMs, examining their architectures, applications, and impact on AI and Generative Models. Starting with foundational concepts, we delve into how MLLMs integrate various data types, including text, images, video and audio, to enable complex AI systems for cross-modal understanding and generation. It covers essential topics such as training methods, architectural components, and practical applications in various fields, from visual storytelling to enhanced accessibility. Through detailed case studies and technical analysis, the text examines prominent MLLM implementations while addressing key challenges in scalability, robustness, and cross-modal learning. Concluding with a discussion of ethical considerations, responsible AI development, and future directions, this authoritative resource provides both theoretical frameworks and practical insights. It offers a balanced perspective on the opportunities and challenges in the development and deployment of MLLMs, and is highly valuable for researchers, practitioners, and students interested in the intersection of natural language processing and computer vision.
Obstacle-aware Gaussian Process Regression
Obstacle-aware trajectory navigation is crucial for many systems. For example, in real-world navigation tasks, an agent must avoid obstacles, such as furniture in a room, while planning a trajectory. Gaussian Process (GP) regression, in its current form, fits a curve to a set of data pairs, with each pair consisting of an input point 'x' and its corresponding target regression value 'y(x)' (a positive data pair). However, to account for obstacles, we need to constrain the GP to avoid a target regression value 'y(x-)' for an input point 'x-' (a negative data pair). Our proposed approach, 'GP-ND' (Gaussian Process with Negative Datapairs), fits the model to the positive data pairs while avoiding the negative ones. Specifically, we model the negative data pairs using small blobs of Gaussian distribution and maximize their KL divergence from the GP. Our framework jointly optimizes for both positive and negative data pairs. Our experiments show that GP-ND outperforms traditional GP learning. Additionally, our framework does not affect the scalability of Gaussian Process regression and helps the model converge faster as the data size increases.
FedRBE -- a decentralized privacy-preserving federated batch effect correction tool for omics data based on limma
Burankova, Yuliya, Klemm, Julian, Lohmann, Jens J. G., Taheri, Ahmad, Probul, Niklas, Baumbach, Jan, Zolotareva, Olga
Batch effects in omics data obscure true biological signals and constitute a major challenge for privacy-preserving analyses of distributed patient data. Existing batch effect correction methods either require data centralization, which may easily conflict with privacy requirements, or lack support for missing values and automated workflows. To bridge this gap, we developed fedRBE, a federated implementation of limma's removeBatchEffect method. We implemented it as an app for the FeatureCloud platform. Unlike its existing analogs, fedRBE effectively handles data with missing values and offers an automated, user-friendly online user interface ( https://featurecloud.ai/app/fedrbe). Leveraging secure multi-party computation provides enhanced security guarantees over classical federated learning approaches. We evaluated our fedRBE algorithm on simulated and real omics data, achieving performance comparable to the centralized method with negligible differences (no greater than 3.6E-13). By enabling collaborative correction without data sharing, fedRBE facilitates large-scale omics studies where batch effect correction is crucial.
Depression detection from Social Media Bangla Text Using Recurrent Neural Networks
Ahmed, Sultan, Rakin, Salman, Waliur, Mohammad Washeef Ibn, Islam, Nuzhat Binte, Hossain, Billal, Akbar, Md. Mostofa
Mostofa Akbar Department of CSE Bangladesh University of Engineering & T echnology Dhaka, Bangladesh mostofa@cse.buet.ac.bd Abstract --Emotion artificial intelligence is a field of study that focuses on figuring out how to recognize emotions, especially in the area of text mining. T oday is the age of social media which has opened a door for us to share our individual expressions, emotions, and perspectives on any event. We can analyze sentiment on social media posts to detect positive, negative, or emotional behavior toward society. One of the key challenges in sentiment analysis is to identify depressed text from social media text that is a root cause of mental ill-health. Furthermore, depression leads to severe impairment in day-to-day living and is a major source of suicide incidents. In this paper, we apply natural language processing techniques on Facebook texts for conducting emotion analysis focusing on depression using multiple machine learning algorithms. Preprocessing steps like stemming, stop word removal, etc. are used to clean the collected data, and feature extraction techniques like stylometric feature, TF-IDF, word embedding, etc. are applied to the collected dataset which consists of 983 texts collected from social media posts. In the process of class prediction, LSTM, GRU, support vector machine, and Naive-Bayes classifiers have been used. We have presented the results using the primary classification metrics including F1-score, and accuracy. This work focuses on depression detection from social media posts to help psychologists to analyze sentiment from shared posts which may reduce the undesirable behaviors of depressed individuals through diagnosis and treatment. I NTRODUCTION Text is the most important means of communication in today's world. Popular online social networking sites such as Facebook, Twitter, MySpace, etc. are mainly text-based. The rapid growth of Social Media has created enough opportunities to share information across time and space. Users are now comfortable contributing more to the content of social media websites and posting their own material. The emergence of internet-based media sources has resulted in the availability of substantial user data for the emotional analysis of text and images.
A Comprehensive Guide to Explainable AI: From Classical Models to LLMs
Hsieh, Weiche, Bi, Ziqian, Jiang, Chuanqi, Liu, Junyu, Peng, Benji, Zhang, Sen, Pan, Xuanhe, Xu, Jiawei, Wang, Jinlang, Chen, Keyu, Feng, Pohsun, Wen, Yizhu, Song, Xinyuan, Wang, Tianyang, Liu, Ming, Yang, Junjie, Li, Ming, Jing, Bowen, Ren, Jintao, Song, Junhao, Tseng, Hong-Ming, Zhang, Yichao, Yan, Lawrence K. Q., Niu, Qian, Chen, Silin, Wang, Yunze, Liang, Chia Xin
Explainable Artificial Intelligence (XAI) addresses the growing need for transparency and interpretability in AI systems, enabling trust and accountability in decision-making processes. This book offers a comprehensive guide to XAI, bridging foundational concepts with advanced methodologies. It explores interpretability in traditional models such as Decision Trees, Linear Regression, and Support Vector Machines, alongside the challenges of explaining deep learning architectures like CNNs, RNNs, and Large Language Models (LLMs), including BERT, GPT, and T5. The book presents practical techniques such as SHAP, LIME, Grad-CAM, counterfactual explanations, and causal inference, supported by Python code examples for real-world applications. Case studies illustrate XAI's role in healthcare, finance, and policymaking, demonstrating its impact on fairness and decision support. The book also covers evaluation metrics for explanation quality, an overview of cutting-edge XAI tools and frameworks, and emerging research directions, such as interpretability in federated learning and ethical AI considerations. Designed for a broad audience, this resource equips readers with the theoretical insights and practical skills needed to master XAI. Hands-on examples and additional resources are available at the companion GitHub repository: https://github.com/Echoslayer/XAI_From_Classical_Models_to_LLMs.
Stochastic Gradient Descent Revisited
The advent of artificial intelligence (AI) has been rendered possible by the spectacular acceleration of computing chip capacity over the last few decades, and has driven a technological revolution that has not spared any aspect of life, including healthcare, supply chain management, social media, etc. AI describes a set of machine learning methods that abandon any form of structural representation of data and look instead into uncovering data patterns to produce probabilistic relationships between input and output quantities of interest. While it has significantly improved people's standards of living, AI has nevertheless engendered many operational risks (e.g. by producing undesirable or unexpected outcomes) as well as systemic risks (e.g. the "Flash Crash", whereby a blue-chip company's share price suddenly plummeted and bounced back in the span of minutes [KL13]). To better manage, prevent and mitigate such risks, some level of mathematical insight must be brought in to shed light onto the inner workings of AI, in order to allow practitioners and regulators alike to act upon it in order to increase its efficiency and curb its shortcomings. SGD is the engine of AI, making it a natural stepping stone toward mathematically explaining AI. Indeed, to capture their intricacies, machine learning problems are often modeled using wide and highly parametrized neural networks [GBC16], which are then solved using SGD or an adaptive variant thereof, namely Adagrad, Adadelta, RMSProp, Adamax or Adam [Rud17]. To approximate a stationary point of a given loss landscape (also referred to as objective or cost function [LZB22; AL24; AMA05]), SGD recursively spawns a trajectory of iterates by factoring in, at each step, a stochastic gradient modulated by a positive learning rate. Whereas classical SGD literature provides convergence guarantees and convergence rates within a (strongly) convex framework [Duf96; BV04; RM51], machine learning models are often highly nonconvex and require new SGD frameworks to better understand and parametrize them.
Risk factor identification and classification of malnutrition among under-five children in Bangladesh: Machine learning and statistical approach
Mahmud, Tasfin, Wara, Tayab Uddin, Joy, Chironjeet Das
This study aims to understand the factors that resulted in under-five children's malnutrition from the Multiple Indicator Cluster (MICS-2019) nationwide surveys and classify different malnutrition stages based on the four well-established machine learning algorithms, namely - Decision Tree (DT), Random Forest (RF), Support Vector Machine (SVM), and Multi-layer Perceptron (MLP) neural network. Accuracy, precision, recall, and F1 scores are obtained to evaluate the performance of each model. The statistical Pearson correlation coefficient analysis is also done to understand the significant factors related to a child's malnutrition. The eligible data sample for analysis was 21,858 among 24,686 samples from the dataset. Satisfactory and insightful results were obtained in each case and, the RF and MLP performed extraordinarily well. For RF, the accuracy was 98.55%, average precision 98.3%, recall value 95.68%, and F1 score 97.13%. For MLP, the accuracy was 98.69%, average precision 97.62%, recall 90.96%, and F1 score of 97.39%. From the Pearson co-efficient, all negative correlation results are enlisted, and the most significant impacts are found for the WAZ2 (Weight for age Z score WHO) (-0.828"), WHZ2 (Weight for height Z score WHO) (-0.706"), ZBMI (BMI Z score WHO) (-0.656"), BD3 (whether child is still being breastfed) (-0.59"), HAZ2 (Height for age Z score WHO) (-0.452"), CA1 (whether child had diarrhea in last 2 weeks) (-0.34"), Windex5 (Wealth index quantile) (-0.161"), melevel (Mother's education) (-0.132"), and CA14/CA16/CA17 (whether child had illness with fever, cough, and breathing) (-0.04) in successive order.