Statistical Learning
Cross-IQA: Unsupervised Learning for Image Quality Assessment
Automatic perception of image quality is a challenging problem that impacts billions of Internet and social media users daily. To advance research in this field, we propose a no-reference image quality assessment (NR-IQA) method termed Cross-IQA based on vision transformer(ViT) model. The proposed Cross-IQA method can learn image quality features from unlabeled image data. We construct the pretext task of synthesized image reconstruction to unsupervised extract the image quality information based ViT block. The pretrained encoder of Cross-IQA is used to fine-tune a linear regression model for score prediction. Experimental results show that Cross-IQA can achieve state-of-the-art performance in assessing the low-frequency degradation information (e.g., color change, blurring, etc.) of images compared with the classical full-reference IQA and NR-IQA under the same datasets.
Analyzing Language Bias Between French and English in Conventional Multilingual Sentiment Analysis Models
Wong, Ethan Parker, M'hiri, Faten
Inspired by the 'Bias Considerations in Bilingual Natural Language Processing' report by Statistics Canada, this study delves into potential biases in multilingual sentiment analysis between English and French. Given a 50-50 dataset of French and English, we aim to determine if there exists a language bias and explore how the incorporation of more diverse datasets in the future might affect the equity of multilingual Natural Language Processing (NLP) systems. By employing Support Vector Machine (SVM) and Naive Bayes models on three balanced datasets, we reveal potential biases in multilingual sentiment classification. Utilizing Fairlearn, a tool for assessing bias in machine learning models, our findings indicate nuanced outcomes. With French data outperforming English across accuracy, recall, and F1 score metrics in both models, hinting at a language bias favoring French. However, Fairlearn's metrics suggest that the SVM approaches equitable levels with a demographic parity ratio of 0.963, 0.989, and 0.985 for the three separate datasets, indicating near-equitable treatment across languages. In contrast, Naive Bayes demonstrates greater disparities, evidenced by a demographic parity ratio of 0.813, 0.908, and 0.961. These findings reveal the importance of developing equitable multilingual NLP systems, particularly as we anticipate the inclusion of more datasets in various languages in the future.
Detecting 5G Narrowband Jammers with CNN, k-nearest Neighbors, and Support Vector Machines
Varotto, Matteo, Heinrichs, Florian, Schuerg, Timo, Tomasin, Stefano, Valentin, Stefan
5G cellular networks are particularly vulnerable against narrowband jammers that target specific control sub-channels in the radio signal. One mitigation approach is to detect such jamming attacks with an online observation system, based on machine learning. We propose to detect jamming at the physical layer with a pre-trained machine learning model that performs binary classification. Based on data from an experimental 5G network, we study the performance of different classification models. A convolutional neural network will be compared to support vector machines and k-nearest neighbors, where the last two methods are combined with principal component analysis. The obtained results show substantial differences in terms of classification accuracy and computation time.
Sora Detector: A Unified Hallucination Detection for Large Text-to-Video Models
Chu, Zhixuan, Zhang, Lei, Sun, Yichen, Xue, Siqiao, Wang, Zhibo, Qin, Zhan, Ren, Kui
The rapid advancement in text-to-video (T2V) generative models has enabled the synthesis of high-fidelity video content guided by textual descriptions. Despite this significant progress, these models are often susceptible to hallucination, generating contents that contradict the input text, which poses a challenge to their reliability and practical deployment. To address this critical issue, we introduce the SoraDetector, a novel unified framework designed to detect hallucinations across diverse large T2V models, including the cutting-edge Sora model. Our framework is built upon a comprehensive analysis of hallucination phenomena, categorizing them based on their manifestation in the video content. Leveraging the state-of-the-art keyframe extraction techniques and multimodal large language models, SoraDetector first evaluates the consistency between extracted video content summary and textual prompts, then constructs static and dynamic knowledge graphs (KGs) from frames to detect hallucination both in single frames and across frames. Sora Detector provides a robust and quantifiable measure of consistency, static and dynamic hallucination. In addition, we have developed the Sora Detector Agent to automate the hallucination detection process and generate a complete video quality report for each input video. Lastly, we present a novel meta-evaluation benchmark, T2VHaluBench, meticulously crafted to facilitate the evaluation of advancements in T2V hallucination detection. Through extensive experiments on videos generated by Sora and other large T2V models, we demonstrate the efficacy of our approach in accurately detecting hallucinations. The code and dataset can be accessed via GitHub.
Generating Feature Vectors from Phonetic Transcriptions in Cross-Linguistic Data Formats
Rubehn, Arne, Nieder, Jessica, Forkel, Robert, List, Johann-Mattis
When comparing speech sounds across languages, scholars often make use of feature representations of individual sounds in order to determine fine-grained sound similarities. Although binary feature systems for large numbers of speech sounds have been proposed, large-scale computational applications often face the challenges that the proposed feature systems -- even if they list features for several thousand sounds -- only cover a smaller part of the numerous speech sounds reflected in actual cross-linguistic data. In order to address the problem of missing data for attested speech sounds, we propose a new approach that can create binary feature vectors dynamically for all sounds that can be represented in the the standardized version of the International Phonetic Alphabet proposed by the Cross-Linguistic Transcription Systems (CLTS) reference catalog. Since CLTS is actively used in large data collections, covering more than 2,000 distinct language varieties, our procedure for the generation of binary feature vectors provides immediate access to a very large collection of multilingual wordlists. Testing our feature system in different ways on different datasets proves that the system is not only useful to provide a straightforward means to compare the similarity of speech sounds, but also illustrates its potential to be used in future cross-linguistic machine learning applications.
Representation Learning of Daily Movement Data Using Text Encoders
Capstick, Alexander, Cui, Tianyu, Chen, Yu, Barnaghi, Payam
Time-series representation learning is a key area of research for remote healthcare monitoring applications. In this work, we focus on a dataset of recordings of in-home activity from people living with Dementia. We design a representation learning method based on converting activity to text strings that can be encoded using a language model fine-tuned to transform data from the same participants within a $30$-day window to similar embeddings in the vector space. This allows for clustering and vector searching over participants and days, and the identification of activity deviations to aid with personalised delivery of care.
A New Dataset and Comparative Study for Aphid Cluster Detection and Segmentation in Sorghum Fields
Rahman, Raiyan, Indris, Christopher, Bramesfeld, Goetz, Zhang, Tianxiao, Li, Kaidong, Chen, Xiangyu, Grijalva, Ivan, McCornack, Brian, Flippo, Daniel, Sharda, Ajay, Wang, Guanghui
Aphid infestations are one of the primary causes of extensive damage to wheat and sorghum fields and are one of the most common vectors for plant viruses, resulting in significant agricultural yield losses. To address this problem, farmers often employ the inefficient use of harmful chemical pesticides that have negative health and environmental impacts. As a result, a large amount of pesticide is wasted on areas without significant pest infestation. This brings to attention the urgent need for an intelligent autonomous system that can locate and spray sufficiently large infestations selectively within the complex crop canopies. We have developed a large multi-scale dataset for aphid cluster detection and segmentation, collected from actual sorghum fields and meticulously annotated to include clusters of aphids. Our dataset comprises a total of 54,742 image patches, showcasing a variety of viewpoints, diverse lighting conditions, and multiple scales, highlighting its effectiveness for real-world applications. In this study, we trained and evaluated four real-time semantic segmentation models and three object detection models specifically for aphid cluster segmentation and detection. Considering the balance between accuracy and efficiency, Fast-SCNN delivered the most effective segmentation results, achieving 80.46% mean precision, 81.21% mean recall, and 91.66 frames per second (FPS). For object detection, RT-DETR exhibited the best overall performance with a 61.63% mean average precision (mAP), 92.6% mean recall, and 72.55 on an NVIDIA V100 GPU. Our experiments further indicate that aphid cluster segmentation is more suitable for assessing aphid infestations than using detection models.
VAEneu: A New Avenue for VAE Application on Probabilistic Forecasting
Koochali, Alireza, Tahaei, Ensiye, Dengel, Andreas, Ahmed, Sheraz
Probabilistic forecasting is essential in decision-making, particularly in fields where accurately assessing risk is critical, such as healthcare [1, 2, 3], weather forecasting [4, 5], flood risk assessment [6], seismic hazard prediction [7, 8], renewable energy sector [9], and economic and financial risk management [10, 11]. These models provide insights into possible future outcomes and their likelihoods, aiding decision-makers in resource allocation, policy formulation, and strategic planning. The importance of these forecasts lies in their ability to model uncertainty about the future in the form of predictive distribution. The ultimate goal of a probabilistic forecaster is to output a predictive distribution with good calibration and sharpness. Calibration is concerned with the statistical consistency between predictive distribution and observation, while sharpness governs the confidence in the forecast itself. A sharp probabilistic forecaster outputs a narrow predictive distribution, which represents high confidence in the forecast. However, sharpness is desirable in conjunction with calibration to employ high confidence aligned with the true distribution.
Towards a Theoretical Understanding of the 'Reversal Curse' via Training Dynamics
Zhu, Hanlin, Huang, Baihe, Zhang, Shaolun, Jordan, Michael, Jiao, Jiantao, Tian, Yuandong, Russell, Stuart
Reversal curse (Berglund et al., 2023) refers to the phenomenon that an auto-regressive LLM that learns "A is B" during training fails to generalize to the reverse direction "B is A", and this task is also termed as "inverse search" in Allen-Zhu and Li (2023). Although some previous works propose different methods to mitigate the reversal curse, including reversing the training dataset (Guo et al., 2024; Golovneva et al., 2024) and training on different objectives such as autoregressive blank infilling (Lv et al., 2023), these methods might negatively affect the model performance on other tasks since they either alter the dataset or the model architecture. Without dataset manipulation or changing the auto-regressive nature (causal structure) of the model, the reversal curse is hard to mitigate even with ICL strategies such as chain-of-thought (Allen-Zhu and Li, 2023; Guo et al., 2024). In this paper, we aim to theoretically study why the reversal curse happens for auto-regressive LLMs. Different from previous work that studies the capacity of (transformer-based (Vaswani et al., 2017)) LLMs through the lens of expressivity (e.g., Yun et al. (2019); Pérez et al. (2021); Feng et al. (2024)), reversal curse cannot be explained by expressivity since a model can express "A is B" is also able to express "B is A". Therefore, we analyze the reversal curse via training dynamics since even if a set of parameters can express a fact in both directions, it might not be reachable through popular training algorithms (e.g., gradient descent, AdamW (Loshchilov and Hutter, 2017)) with training data only presented in one direction. We summarize our main contributions as follows: We theoretically analyze reversal curse where training or test sequences have the from "A B" or "B A" via training dynamics of (stochastic) gradient descent under two auto-regressive models: a bilinear model (Section 3) and one-layer transformers under certain assumptions similar to Tian et al. (2023a) (Section 4). The analysis of the training dynamics of both models reveals a core reason why the reversal curse happens: the weights of the autoregressive models are asymmetric, i.e., the increase of weights from the token A to token B
Community Detection for Heterogeneous Multiple Social Networks
Zhu, Ziqing, Yuan, Guan, Zhou, Tao, Cao, Jiuxin
The community plays a crucial role in understanding user behavior and network characteristics in social networks. Some users can use multiple social networks at once for a variety of objectives. These users are called overlapping users who bridge different social networks. Detecting communities across multiple social networks is vital for interaction mining, information diffusion, and behavior migration analysis among networks. This paper presents a community detection method based on nonnegative matrix tri-factorization for multiple heterogeneous social networks, which formulates a common consensus matrix to represent the global fused community. Specifically, the proposed method involves creating adjacency matrices based on network structure and content similarity, followed by alignment matrices which distinguish overlapping users in different social networks. With the generated alignment matrices, the method could enhance the fusion degree of the global community by detecting overlapping user communities across networks. The effectiveness of the proposed method is evaluated with new metrics on Twitter, Instagram, and Tumblr datasets. The results of the experiments demonstrate its superior performance in terms of community quality and community fusion.