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TFAD: A Decomposition Time Series Anomaly Detection Architecture with Time-Frequency Analysis

arXiv.org Artificial Intelligence

Time series anomaly detection is a challenging problem due to the complex temporal dependencies and the limited label data. Although some algorithms including both traditional and deep models have been proposed, most of them mainly focus on time-domain modeling, and do not fully utilize the information in the frequency domain of the time series data. In this paper, we propose a Time-Frequency analysis based time series Anomaly Detection model, or TFAD for short, to exploit both time and frequency domains for performance improvement. Besides, we incorporate time series decomposition and data augmentation mechanisms in the designed time-frequency architecture to further boost the abilities of performance and interpretability. Empirical studies on widely used benchmark datasets show that our approach obtains state-of-the-art performance in univariate and multivariate time series anomaly detection tasks. Code is provided at https://github.com/DAMO-DI-ML/CIKM22-TFAD.


Autoregressive Conditional Neural Processes

arXiv.org Artificial Intelligence

Conditional neural processes (CNPs; Garnelo et al., 2018a) are attractive meta-learning models which produce well-calibrated predictions and are trainable via a simple maximum likelihood procedure. Although CNPs have many advantages, they are unable to model dependencies in their predictions. Various works propose solutions to this, but these come at the cost of either requiring approximate inference or being limited to Gaussian predictions. In this work, we instead propose to change how CNPs are deployed at test time, without any modifications to the model or training procedure. Instead of making predictions independently for every target point, we autoregressively define a joint predictive distribution using the chain rule of probability, taking inspiration from the neural autoregressive density estimator (NADE) literature. We show that this simple procedure allows factorised Gaussian CNPs to model highly dependent, non-Gaussian predictive distributions. Perhaps surprisingly, in an extensive range of tasks with synthetic and real data, we show that CNPs in autoregressive (AR) mode not only significantly outperform non-AR CNPs, but are also competitive with more sophisticated models that are significantly more computationally expensive and challenging to train. This performance is remarkable given that AR CNPs are not trained to model joint dependencies. Our work provides an example of how ideas from neural distribution estimation can benefit neural processes, and motivates research into the AR deployment of other neural process models.


LRDB: LSTM Raw data DNA Base-caller based on long-short term models in an active learning environment

arXiv.org Artificial Intelligence

The first important step in extracting DNA characters is using the output data of MinION devices in the form of electrical current signals. Various cutting-edge base callers use this data to detect the DNA characters based on the input. In this paper, we discuss several shortcomings of prior base callers in the case of time-critical applications, privacy-aware design, and the problem of catastrophic forgetting. Next, we propose the LRDB model, a lightweight open-source model for private developments with a better read-identity (0.35% increase) for the target bacterial samples in the paper. We have limited the extent of training data and benefited from the transfer learning algorithm to make the active usage of the LRDB viable in critical applications. Henceforth, less training time for adapting to new DNA samples (in our case, Bacterial samples) is needed. Furthermore, LRDB can be modified concerning the user constraints as the results show a negligible accuracy loss in case of using fewer parameters. We have also assessed the noise-tolerance property, which offers about a 1.439% decline in accuracy for a 15dB noise injection, and the performance metrics show that the model executes in a medium speed range compared with current cutting-edge models.


Polar-VQA: Visual Question Answering on Remote Sensed Ice sheet Imagery from Polar Region

arXiv.org Artificial Intelligence

For glaciologists, studying ice sheets from the polar regions is critical. With the advancement of deep learning techniques, we can now extract high-level information from the ice sheet data (e.g., estimating the ice layer thickness, predicting the ice accumulation for upcoming years, etc.). However, a vision-based conversational deep learning approach has not been explored yet, where scientists can get information by asking questions about images. In this paper, we have introduced the task of Visual Question Answering (VQA) on remote-sensed ice sheet imagery. To study, we have presented a unique VQA dataset, Polar-VQA, in this study. All the images in this dataset were collected using four types of airborne radars. The main objective of this research is to highlight the importance of VQA in the context of ice sheet research and conduct a baseline study of existing VQA approaches on Polar-VQA dataset.


How Could AI Make Education More Fun? : Academics : University Herald How Could AI Make Education More Fun? : Academics : University Herald

#artificialintelligence

AI in the education system has been applied with a traditional approach for decades. On that note, computer-based teaching and learning programs were first developed in the 1960s. However, in the last few years, the presence of AI in schools and colleges has gradually become accepted as an effective tool for automating numerous tasks. For example, If students have questions about their schedule, chatbots can answer them. AI-generated emails remind students to register for classes, notify them of important deadlines, and turn in assignments.


CoTEVer: Chain of Thought Prompting Annotation Toolkit for Explanation Verification

arXiv.org Artificial Intelligence

Chain-of-thought (CoT) prompting enables large language models (LLMs) to solve complex reasoning tasks by generating an explanation before the final prediction. Despite it's promising ability, a critical downside of CoT prompting is that the performance is greatly affected by the factuality of the generated explanation. To improve the correctness of the explanations, fine-tuning language models with explanation data is needed. However, there exists only a few datasets that can be used for such approaches, and no data collection tool for building them. Thus, we introduce CoTEVer, a tool-kit for annotating the factual correctness of generated explanations and collecting revision data of wrong explanations. Figure 1: Example of Explanation Verification and Answer Furthermore, we suggest several use cases Verification of GPT-3's output. Explanation Verification where the data collected with CoTEVer can requires additional knowledge which makes it be utilized for enhancing the faithfulness of hard for annotators to intuitively write a revised explanation explanations. Our toolkit is publicly available and answer.


On Differentially Private Online Predictions

arXiv.org Artificial Intelligence

In this work we introduce an interactive variant of joint differential privacy towards handling online processes in which existing privacy definitions seem too restrictive. We study basic properties of this definition and demonstrate that it satisfies (suitable variants) of group privacy, composition, and post processing. We then study the cost of interactive joint privacy in the basic setting of online classification. We show that any (possibly non-private) learning rule can be effectively transformed to a private learning rule with only a polynomial overhead in the mistake bound. This demonstrates a stark difference with more restrictive notions of privacy such as the one studied by Golowich and Livni (2021), where only a double exponential overhead on the mistake bound is known (via an information theoretic upper bound).


Drop Edges and Adapt: a Fairness Enforcing Fine-tuning for Graph Neural Networks

arXiv.org Artificial Intelligence

The rise of graph representation learning as the primary solution for many different network science tasks led to a surge of interest in the fairness of this family of methods. Link prediction, in particular, has a substantial social impact. However, link prediction algorithms tend to increase the segregation in social networks by disfavoring the links between individuals in specific demographic groups. This paper proposes a novel way to enforce fairness on graph neural networks with a fine-tuning strategy. We Drop the unfair Edges and, simultaneously, we Adapt the model's parameters to those modifications, DEA in short. We introduce two covariance-based constraints designed explicitly for the link prediction task. We use these constraints to guide the optimization process responsible for learning the new "fair" adjacency matrix. One novelty of DEA is that we can use a discrete yet learnable adjacency matrix in our fine-tuning. We demonstrate the effectiveness of our approach on five real-world datasets and show that we can improve both the accuracy and the fairness of the link prediction tasks. In addition, we present an in-depth ablation study demonstrating that our training algorithm for the adjacency matrix can be used to improve link prediction performances during training. Finally, we compute the relevance of each component of our framework to show that the combination of both the constraints and the training of the adjacency matrix leads to optimal performances.


Astronomers pick up EIGHT mysterious radio signals from outer space

Daily Mail - Science & tech

In 1996 Nasa and the White House made the explosive announcement that the rock contained traces of Martian bugs. The meteorite, catalogued as Allen Hills (ALH) 84001, crashed onto the frozen wastes of Antarctica 13,000 years ago and was recovered in 1984. Photographs were released showing elongated segmented objects that appeared strikingly lifelike.


Antarctica Doomsday Glacier: 'We should all be very concerned'

Al Jazeera

Scientists studying Antarctica's vast Thwaites Glacier – nicknamed the "Doomsday Glacier" – say warm water is seeping into its weak spots, threatening its demise and a massive sea rise. Thwaites, which is roughly the size of Florida, represents more than half a metre (1.6 feet) of global sea level rise potential, and could destabilise neighbouring glaciers that could cause a further 3-metre (9.8-foot) rise. As part of the International Thwaites Glacier Collaboration – the biggest field campaign ever attempted in Antarctica – a team of 13 scientists from the United States and United Kingdom spent about six weeks on the glacier in late 2019 and early 2020. Using an underwater robot vehicle known as Icefin, mooring data and sensors, they monitored the glacier's grounding line, where ice slides off the glacier and meets the ocean for the first time. In one of two papers published on Wednesday in the journal Nature, led by Cornell University-based scientist Britney Schmidt, researchers found warmer water was making its way into crevasses and other openings known as terraces, causing sideways melt of 30 metres (98 feet) or more per year.