Anomaly detection in data streams has been an active research area due to the increasing volume and complexity of data generated by IoT devices and smart environments [2]. Traditional anomaly detection methods, such as statistical techniques [5], clustering [16], and classification [8], have been applied to data streams [6], with varying degrees of success. However, they often struggle to adapt to the dynamic nature of data streams, which may have changing distributions and evolving patterns [5]. For example, during a timed event, the traffic pattern can change dramatically, potentially causing statistical methods that rely on historical data to label the surge in traffic as an anomaly due to the shift in statistical properties like mean and variance [17]. In addition, the traditional clustering methods might not recognize the sudden appearance of a new cluster as an anomaly, leading to delayed detection, or traditional classifiers might struggle to identify novel patterns that were not present in the training data [6]. In summary, traditional anomaly detection methods have limitations that become more pronounced in dynamic data streams with changing distributions and evolving patterns. The technical challenges of concept drift [17], high-dimensional data [7], computational efficiency [18], and feature engineering [19] contribute to their struggles in adapting to these scenarios. This has prompted the exploration of more advanced techniques, including deep learning-based approaches, which have shown better adaptability and scalability in handling the dynamic nature of data streams.

Recently, deep learning-based techniques [2] have been proposed for data stream anomaly detection, including autoencoders [20], recurrent neural networks (RNNs) [21], and convolutional neural networks (CNNs) [22]. These methods have demonstrated better adaptability and scalability compared to traditional methods, but they still face challenges in dealing with heterogeneous data types and efficiently focusing on relevant features. Specifically, deep learning techniques face significant challenges in dealing with heterogeneous data types and efficiently focusing on relevant features [2]. These challenges include handling diverse data types, ensuring feature relevance and selection, addressing data imbalance, and interpreting deep models [23]. Heterogeneous data types, such as numerical, categorical, text, image, and time series data, can be challenging to integrate and process effectively [7,24]. Researchers are exploring techniques to handle multiple data types [25], such as specialized network architectures [26] or converting different data types into a common feature space [27]. Feature engineering and selection techniques aim to identify the most informative features, while data imbalance can lead to models favoring the majority class and performing poorly in anomaly detection [28]. Interpretable models are crucial to understanding the underlying patterns learned by deep learning models, such as in manufacturing processes where engineers need to know which factors contributed to anomaly detection [29]. Researchers are developing techniques to explain deep model decisions, such as attention mechanisms, feature attribution methods, and gradient-based visualizations, to provide insights into which features were influential in making anomaly predictions [30].

Cross-modal learning [31] refers to the process of learning shared representations from multiple data modalities, such as images, text, and audio. It has shown great potential in various applications, including multimedia retrieval [32], recommendation systems [33], and multimodal sentiment analysis [25]. Several methods have been proposed for cross-modal learning, including deep neural networks [34], matrix factorization [35], and probabilistic graphical models [36]. Recently, cross-modal learning has been integrated with attention mechanisms to improve the interpretability and performance of the learned representations [37,38,39]. However, the application of cross-modal learning to anomaly detection in data streams from smart communication environments is still relatively unexplored. This approach offers several benefits, but also presents challenges, such as developing effective fusion strategies, addressing domain-specific issues, dealing with varying data modalities, and managing computational complexity [36]. Additionally, data privacy and ethics are critical concerns in smart communication environments, and researchers must address these concerns when designing cross-modal anomaly detection systems [25].

Attention mechanisms have been introduced in neural networks to help the model focus on the most relevant parts of the input data for a specific task [12]. The concept of attention was initially proposed in the context of Natural Language Processing (NLP) [15] and has since been extended to various domains, such as computer vision [14] and speech recognition [40]. Different types of attention mechanisms have been proposed, including self-attention [41], local attention [42], and global attention [43]. Attention mechanisms have also been combined with other neural network architectures, such as RNNs [44], CNNs [45], and Transformer models [46], to improve their performance and interpretability. The application of attention mechanisms in anomaly detection has shown promising results, particularly in terms of handling large-scale and high-dimensional data [27]. However, incorporating dynamic attention mechanisms into cross-modal learning for anomaly detection in data streams remains a challenge. Specifically, incorporating dynamic attention mechanisms into cross-modal learning for anomaly detection in data streams requires a careful balance between adaptability, efficiency, interpretability, and performance [37]. Researchers need to devise novel approaches that address these challenges and tailor dynamic attention mechanisms to the specific requirements of dynamic data streams and multi-modal data fusion [14]. Despite the challenges, successfully implementing dynamic attention can significantly enhance the accuracy and robustness of anomaly detection systems in complex and rapidly evolving environments [12].

In summary, research gaps from the literature review in anomaly detection in dynamic environments include adapting traditional methods to handle changing distributions and patterns, integrating heterogeneous data types, improving the interpretability of deep models, exploring cross-modal anomaly detection, incorporating dynamic attention mechanisms, and addressing privacy and ethics concerns. These areas highlight opportunities for innovation and exploration in anomaly detection in smart communication environments, particularly in integrating heterogeneous data types, enhancing interpretability, and effectively utilizing dynamic attention mechanisms and cross-modal learning techniques.

By addressing these gaps, the proposed approach proposes a more effective anomaly detection method that can handle diverse data types, improve interpretability, and maintain privacy and ethics in cross-modal anomaly detection systems. Specifically, this paper presents a novel CM-DANA for detecting anomalies in data streams generated from smart communication environments. The proposed architecture leverages the advantages of cross-modal learning and dynamic attention mechanisms to effectively analyze heterogeneous data streams from different cyber modalities and identify anomalous patterns in real-time. Recent advancements inspire this approach in cross-modal learning and attention mechanisms in neural networks. Cross-modal learning has shown its potential in various applications where data comes from multiple sources or modalities, while attention mechanisms have been successful in helping models focus on relevant parts of input data for specific tasks. By combining these two concepts, our proposed approach not only improves the overall performance of anomaly detection but also enhances the interpretability and adaptability of the model in handling diverse and evolving data patterns.

The proposed method addresses research gaps in anomaly detection in dynamic data streams from smart communication environments by enhancing traditional methods, integrating heterogeneous data types, enhancing interpretable deep models, incorporating cross-modal learning, and incorporating dynamic attention mechanisms. These contributions can help develop more accurate, adaptive, and interpretable anomaly detection systems that can effectively operate in complex and rapidly evolving scenarios. By incorporating concepts from both the dynamic attention and anomaly detection domain, the proposed CM-DANA technique ensures that data from different modalities are integrated in an accurate way. By focusing on these contributions, the proposed approach makes significant strides in advancing the field of anomaly detection in dynamic data streams from smart communication environments.