MOTIVATION: Deep generative models have transformed drug molecule generation. However, molecules exhibit complex hierarchical structures, requiring models to simultaneously balance macroscopic topological coherence and microscopic chemical self-consistency. Although autoregressive (AR) and discrete diffusion paradigms are highly complementary, integrating their advantages within a unified architecture remains severely limited by traditional "atom-by-atom" fine-grained modeling. RESULTS: We propose MARD-Mol, a hybrid AR-diffusion framework based on motif-inspired units. By elevating the representation granularity from atoms to motif-inspired units and introducing a dual-stream hierarchical attention mechanism, it couples inter-unit AR global scaffold planning with intra-unit discrete diffusion generation. To support goal-directed drug discovery, we reformulate property optimization into an iterative "diagnose-and-repair" process, enabling targeted optimization of defective motifs while preserving the global scaffold. Extensive experiments demonstrate that MARD-Mol achieves an 86.0% Quality score in de novo generation and exhibits superior performance in fragment-constrained and multi-objective optimization, establishing a new paradigm for high-quality drug design. AVAILABILITY AND IMPLEMENTATION: The source code and datasets used in this study are available at GitHub: https://github.com/CSUBioGroup/MARD-Mol.

Self-correction of large language models (LLMs) emerges as a critical component for enhancing their reasoning performance. Although various self-correction methods have been proposed, a comprehensive evaluation of these methods remains largely unexplored, and the question of whether LLMs can truly correct themselves is a matter of significant interest and concern. In this study, we introduce CorrectBench, a benchmark developed to evaluate the effectiveness of self-correction strategies, including intrinsic, external, and fine-tuned approaches, across three tasks: commonsense reasoning, mathematical reasoning, and code generation. Our findings reveal that: 1) Self-correction methods can improve accuracy, especially for complex reasoning tasks; 2) Mixing different self-correction strategies yields further improvements, though it reduces efficiency; 3) Reasoning LLMs (e.g., DeepSeek-V3) have limited optimization under additional self-correction methods and have high time costs. Interestingly, a comparatively simple chain-of-thought (CoT) baseline demonstrates competitive accuracy and efficiency. These results underscore the potential of self-correction to enhance LLM's reasoning performance while highlighting the ongoing challenge of improving their efficiency. Consequently, we advocate for further research focused on optimizing the balance between reasoning capabilities and operational efficiency.

Brain-inspired hyperdimensional computing (HDC) is an emerging machine learning paradigm leveraging high-dimensional spaces for efficient tasks like pattern recognition and medical diagnostics. As a lightweight alternative to deep neural networks, HDC offers smaller model sizes, reduced computation, and memory-centric processing. However, deploying HDC in safety-critical applications, such as healthcare and robotics, is challenged by hardware-induced errors. This paper investigates HDC's robustness to memory errors via extensive bit-flip injection experiments on item and associative memories. Results reveal that certain bit-flips severely degrade accuracy. To address this, we introduce the Hyperdimensional Bit-Flip Search (HD-BFS), a similarity-guided method for identifying vulnerabilities and crafting efficient attacks, where flipping just 6 critical bits—3.9% of random bit-flips—reduces accuracy to chance levels. We further propose Hyperdimensional Accelerated Bit-Flip Search (HD-ABFS), which narrows the search space by targeting critical dimensions and most significant bits (MSBs), achieving up to 282$\times$speedup over HD-BFS. Finally, we develop an effective protection mechanism to enhance model safety. These insights highlight HDC's resilience to random errors, offer robust defenses against targeted attacks, and advance the security and reliability of HDC systems.

Hyperdimensional Computing (HDC), also known as Vector Symbolic Architecture (VSA), is an emerging AI algorithm inspired by the way the human brain functions. Compared with deep neural networks (DNNs), HDC possesses several advantages such as smaller model size, less computation cost, and one/few-shot learning, making it a promising alternative computing paradigm. With the increasing deployment of AI in safety-critical systems such as healthcare and robotics, it is not only important to strive for high accuracy, but also to ensure its robustness under even highly uncertain and adversarial environments. However, recent studies show that HDC, just like DNNs, is vulnerable to both cyber attacks (e.g., adversarial attacks) and hardware errors (e.g., memory failures). While a growing body of research has been studying the robustness of HDC, there is a lack of systematic review of research efforts on this increasingly-important topic. To the best of our knowledge, this paper presents the first survey dedicated to review the research efforts made to the robustness of HDC against cyber attacks and hardware errors. While the performance and accuracy of HDC as an AI method still expects future theoretical advancement, this survey paper aims to shed light and call for community efforts on robustness research of HDC.

The security and robustness of machine learning algorithms have become increasingly important as they are used in critical applications such as natural language processing (NLP), e.g., text-based spam detection. Recently, the emerging brain-inspired hyperdimensional computing (HDC), compared to deep learning methods, has shown advantages such as compact model size, energy efficiency, and capability of few-shot learning in various NLP applications. While HDC has been demonstrated to be vulnerable to adversarial attacks in image and audio input, there is currently very limited study on its adversarial security to NLP tasks, which is arguable one of the most suitable applications for HDC. In this paper, we present a novel study on the adversarial attack of HDC-based NLP applications. By leveraging the unique properties in HDC, the similarity-based inference, we propose similarity-guided approaches to automatically generate adversarial text samples for HDC. Our approach is able to achieve up to 89% attack success rate. More importantly, by comparing with unguided brute-force approach, similarity-guided attack achieves a speedup of 2.4X in generating adversarial samples. Our work opens up new directions and challenges for future adversarially-robust HDC model design and optimization.

Federated learning is a decentralized machine learning strategy that trains the model by using data stored across multiple decentralized edge devices or servers. Studies on federated learning currently focus primarily on neural network-based learning methods, which usually require powerful hardware and are relatively not energy-efficient. Recently, hyperdimensional computing (HDC) emerges as a potential alternative solution to neural networks, particularly on resource-constrained platforms such as edge intelligence systems. HDC mimics the “human brain” at the functionality level that learns with the attributes of brain circuits, including high-dimensionality and fully distributed holographic representation. Although there are existing works related to HDC-based federated learning, a comprehensive study on how HDC-based federated learning performs in different settings is still absent. To bridge this gap, we present a comprehensive case study on federated learning using HDC under two model aggregation strategies: hypervector aggregation and associative memory aggregation. We also perform extensive experiments with various settings, including data distribution, number of clients, and local training epochs. We also analyze their communication costs under these settings. Our results show that using the strategy of associative memory aggregation can achieve up to 95% communication cost reduction compared to hypervector aggregation. In addition, HDC-based federated learning system shows high robustness in training with Non-IID data. This study aims to shed light and provide guidance in opening up new directions and challenges for future HDC-based federated learning system design and optimization.

Recently, brain-inspired hyperdimensional computing (HDC) has demonstrated promising capability in a wide range of applications such as medical diagnosis, human activity recognition, and voice classification, etc. Despite the growing popularity of HDC, its memory-centric computing characteristics make the associative memory implementation under significant energy consumption due to the massive data storage and processing. In this paper, we present a systematic case study to leverage the application-level error resilience of HDC to reduce the energy consumption of HDC associative memory by using voltage scaling. Evaluation results on various applications show that our proposed approach can achieve 47.6% energy saving on associative memory with a 1% accuracy loss. We further explore two low-cost error masking methods: word masking and bit masking, to mitigate the impact of voltage scaling-induced errors. Experimental results show that the proposed word masking (bit masking) method can further enhance energy saving up to 62.3% (72.5%) with accuracy loss ≤1%.

Brain-inspired hyperdimensional computing (HDC) has demonstrated promising capability in various cognition tasks such as robotics, bio-medical signal analysis, and natural language processing. Compared to deep neural networks, HDC models show advantages such as light-weight model and one/few-shot learning capabilities, making it a promising alternative paradigm to traditional resource-demanding deep learning models particularly in edge devices with limited resources. Despite the growing popularity of HDC, the robustness of HDC models and the approaches to enhance HDC robustness has not been systematically analyzed and sufficiently examined. HDC relies on high-dimensional numerical vectors referred to as hypervectors (HV) to perform cognition tasks and the values inside the HVs are critical to the robustness of an HDC model. We propose ScaleHD, an adaptive scaling method that scales the value of HVs in the associative memory of an HDC model to enhance the robustness of HDC models. We propose three different modes of ScaleHD including Global-ScaleHD, Class-ScaleHD, and (Class + Clip)-ScaleHD which are based on different adaptive scaling strategies. Results show that ScaleHD is able to enhance HDC robustness against memory errors up to 10,000X. Moreover, we leverage the enhanced HDC robustness in exchange for energy saving via voltage scaling method. Experimental results show that ScaleHD can reduce energy consumption on HDC memory system up to 72.2% with less than 1% accuracy loss.

Brain-inspired hyperdimensional computing (HDC) is an emerging computational paradigm that has achieved success in various domains. HDC mimics brain cognition and lever-ages hyperdimensional vectors with fully distributed holographic representation and (pseudo)randomness. Compared to the traditional machine learning methods, HDC offers several critical advantages, including smaller model size, less computation cost, and one-shot learning capability, making it a promising candidate in low-power platforms. Despite the growing popularity of HDC, the robustness of HDC models has not been systematically explored. This paper presents a study on the robustness of HDC to errors in associative memory—the key component storing the class representations in HDC. We perform extensive error injection experiments to the associative memory in a number of HDC models (and datasets), sweeping the error rates and varying HDC configurations (i.e., dimension and data width). Empirically, we observe that HDC is considerably robust to errors in the associative memory, opening up opportunities for further optimizations. Further, results show that HDC robustness varies significantly with different HDC configurations such as data width. Moreover, we explore a low-cost error masking mechanism in the associative memory to enhance its robustness.

Optimal store placement aims to identify the optimal location for a new brick-and-mortar store that can maximize its sale by analyzing and mining users’ preferences from large-scale urban data. In recent years, the expansion of chain enterprises in new cities brings some challenges because of two aspects: (1) data scarcity in new cities, so most existing models tend to not work (i.e., overfitting), because the superior performance of these works is conditioned on large-scale training samples; (2) data distribution discrepancy among different cities, so knowledge learned from other cities cannot be utilized directly in new cities. In this article, we propose a task-adaptative model-agnostic meta-learning framework, namely, MetaStore, to tackle these two challenges and improve the prediction performance in new cities with insufficient data for optimal store placement, by transferring prior knowledge learned from multiple data-rich cities. Specifically, we develop a task-adaptative meta-learning algorithm to learn city-specific prior initializations from multiple cities, which is capable of handling the multimodal data distribution and accelerating the adaptation in new cities compared to other methods. In addition, we design an effective learning strategy for MetaStore to promote faster convergence and optimization by sampling high-quality data for each training batch in view of noisy data in practical applications. The extensive experimental results demonstrate that our proposed method leads to state-of-the-art performance compared with various baselines.

Store site recommendation aims to predict the value of the store at candidate locations and then recommend the optimal location to the company for placing a new brick-and-mortar store. Most existing studies focus on learning machine learning or deep learning models based on large-scale training data of existing chain stores in the same city. However, the expansion of chain enterprises in new cities suffers from data scarcity issues, and these models do not work in the new city where no chain store has been placed (i.e., cold-start problem). In this article, we propose a unified approach for cold-start store site recommendation, Weighted Adversarial Network with Transferability weighting scheme (WANT), to transfer knowledge learned from a data-rich source city to a target city with no labeled data. In particular, to promote positive transfer, we develop a discriminator to diminish distribution discrepancy between source city and target city with different data distributions, which plays the minimax game with the feature extractor to learn transferable representations across cities by adversarial learning. In addition, to further reduce the risk of negative transfer, we design a transferability weighting scheme to quantify the transferability of examples in source city and reweight the contribution of relevant source examples to transfer useful knowledge. We validate WANT using a real-world dataset, and experimental results demonstrate the effectiveness of our proposed model over several state-of-the-art baseline models.

Store site recommendation is one of the essential business services in smart cities for brick-and-mortar enterprises. In recent years, the proliferation of multisource data in cities has fostered unprecedented opportunities to the data-driven store site recommendation, which aims at leveraging large-scale user-generated data to analyze and mine users’ preferences for identifying the optimal location for a new store. However, most works in store site recommendation pay more attention to a single data source which lacks some significant data (e.g., consumption data and user profile data). In this paper, we aim to study the store site recommendation in a fine-grained manner. Specifically, we predict the consumption level of different users at the store based on multisource data, which can not only help the store placement but also benefit analyzing customer behavior in the store at different time periods. To solve this problem, we design a novel model based on the deep neural network, named DeepStore, which learns low- and high-order feature interactions explicitly and implicitly from dense and sparse features simultaneously. In particular, DeepStore incorporates three modules: 1) the cross network; 2) the deep network; and 3) the linear component. In addition, to learn the latent feature representation from multisource data, we propose two embedding methods for different types of data: 1) the filed embedding and 2) attention-based spatial embedding. Extensive experiments are conducted on a real-world dataset including store data, user data, and point-of-interest data, the results demonstrate that DeepStore outperforms the state-of-the-art models.

This paper reports on the development of a simulation gaming platform to study the dynamics of decision making when multiple stakeholders are tasked to design and manage a flexible engineering system. Flexibility in design and management provides the "right, but not the obligation, to change a system in the face of uncertainty." This approach shows clear lifecycle performance improvements for complex systems, as compared to standard design and management approaches. The process of enabling and managing flexibility involves many stakeholders at different levels of the decision-making process. Decisions at a higher level (e.g. system owner, client) impact the decision space available to other stakeholders down the line (e.g. system designers, operators), which affects the ability to respond to change. Managing different sources of flexibility in operations is challenging, especially when subjected to economic and/or legal constraints, information asymmetry, different uncertainty sources, and other agency problems between the stakeholders. The simulation gaming platform provides a way to devise, study, and evaluate the effectiveness of training and other uncertainty management techniques experimentally to help stakeholders better design and manage complex systems under uncertainty. Results of preliminary experiments are shown in the context of an urban emergency services system.