Most of the data-driven satellite telemetry data anomaly detection methods suffer from high false positive rate and poor interpretability. To solve the above problems, we propose an anomaly detection framework using causal network and Feature-Attention-based Long Short-Term Memory (LSTM). In our method, a causal network of telemetry parameters is constructed by calculating Normalized Modified Conditional Transfer Entropy (NMCTE) and optimized by conditional independence tests based on the Conditional Mutual Information (CMI). Then, a Feature-Attention-based LSTM model combines feature attention and causal network (called CN-FA-LSTM) is established to predict telemetry data, and a nonparametric dynamic k-sigma threshold updating method is proposed to set thresholds. Case study on a real satellite demonstrates that anomaly detection using the CN-FA-LSTM and nonparametric dynamic k-sigma threshold updating has an average F1-score of 0.9462 and false positive rate of 0.0021, which are better than the baseline methods. Furthermore, CN-FA-LSTM has a stronger interpretability than other commonly used prediction models. Supplementary experiment on two public datasets verifies the universal applicability of our method.

With its powerful expressive capability and intuitive presentation, the knowledge graph has emerged as one of the primary forms of knowledge representation and management. However, the presence of biases in our cognitive and construction processes often leads to varying degrees of incompleteness and errors within knowledge graphs. To address this, reasoning becomes essential for supplementing and rectifying these shortcomings. Logical rule-based knowledge graph reasoning methods excel at performing inference by uncovering underlying logical rules, showcasing remarkable generalization ability and interpretability. Moreover, the flexibility of logical rules allows for seamless integration with diverse neural network models, thereby offering promising prospects for research and application. Despite the growing number of logical rule-based knowledge graph reasoning methods, a systematic classification and analysis of these approaches is lacking. In this review, we delve into the relevant research on logical rule-based knowledge graph reasoning, classifying them into four categories: methods based on inductive logic programming (ILP), methods that unify probabilistic graphical models and logical rules, methods that unify embedding techniques and logical rules, and methods that jointly use neural networks (NNs) and logical rules. We introduce and analyze the core concepts and key techniques, as well as the advantages and disadvantages associated with these methods, while also providing a comparative evaluation of their performance. Furthermore, we summarize the main problems and challenges, and offer insights into potential directions for future research.

Most of the spacecraft telemetry anomaly detection methods based on statistical models suffer from the problems of high false negatives, long time consumption, and poor interpretability. Besides, complex interactions, which may determine the propagation of anomalous mode between telemetry parameters, are often ignored. To discover the complex interaction between spacecraft telemetry parameters and improve the efficiency and accuracy of anomaly detection, we propose an anomaly detection framework based on parametric causality and Double-Criteria Drift Streaming Peaks Over Threshold (DCDSPOT). We propose Normalized Effective Transfer Entropy (NETE) to reduce the error and noise caused by nonstationarity of the data in the calculation of transfer entropy, and then apply NETE to improve the Multivariate Effective Source Selection (MESS) causal inference algorithm to infer parametric causality. We define the Weighted Source Parameter (WSP) of the target parameter to be detected, then DSPOT is employed to set multi-tier thresholds for target parameter and WSP. At last, two criteria are formulated to determine anomalies. Additionally, to cut the time consumption of the DCDSPOT, we apply Probability Weighted Moments (PWM) for parameter estimation of Generalized Pareto Distribution (GPD). Experiments on real satellite telemetry dataset shows that our method has higher recall and F1-score than other commonly used methods, and the running time is also significantly reduced.

Event Causality Identification (ECI) has become an essential task in Natural Language Processing (NLP), focused on automatically detecting causal relationships between events within texts. This comprehensive survey systematically investigates fundamental concepts and models, developing a systematic taxonomy and critically evaluating diverse models. We begin by defining core concepts, formalizing the ECI problem, and outlining standard evaluation protocols. Our classification framework divides ECI models into two primary tasks: Sentence-level Event Causality Identification (SECI) and Document-level Event Causality Identification (DECI). For SECI, we review models employing feature pattern-based matching, machine learning classifiers, deep semantic encoding, prompt-based fine-tuning, and causal knowledge pre-training, alongside data augmentation strategies. For DECI, we focus on approaches utilizing deep semantic encoding, event graph reasoning, and prompt-based fine-tuning. Special attention is given to recent advancements in multi-lingual and cross-lingual ECI, as well as zero-shot ECI leveraging Large Language Models (LLMs). We analyze the strengths, limitations, and unresolved challenges associated with each approach. Extensive quantitative evaluations are conducted on four benchmark datasets to rigorously assess the performance of various ECI models. We conclude by discussing future research directions and highlighting opportunities to advance the field further.