Smart contracts are self-executing computer programs on blockchains. With the development of blockchain technology, the number of smart contracts has grown rapidly, as has the concern for their security. Regrettably, inconsistencies between the logic implemented in the code and the intentions described in the comments, known as Code–Comment Inconsistencies (CCI), are frequently present in some smart contracts. These inconsistencies can mislead readers in understanding the contract code and, in severe cases, may lead to vulnerabilities and economic losses. Existing learning-based methods are not tailored for smart contract languages, overlook the issue of insufficient context information caused by comment references and nested intentions, and rely on large-scale labeled data; whereas rule-based methods struggle to accommodate the flexibility with which developers express intentions, often resulting in false positives. To tackle the challenges posed by insufficient context information and the scarcity of labeled data, we introduce CCIHunter, a tool designed to detect CCIs in smart contracts. CCIHunter addresses the issue of insufficient context information during data modeling and incorporates a two-stage pre-training process that does not depend on labeled data to enhance its detection capabilities. Specifically, CCIHunter enhances comments based on templates and models code as a heterogeneous graph based on function calls. It utilizes CodeBERT and UniMp to generate embeddings for comments and code, respectively, and then calculates the similarity between these two embeddings. Consistency is judged by combining code embeddings, comment embeddings, and similarity scores. Notably, CCIHunter undergoes a two-stage pre-training that includes contrastive learning and mutation analysis, aiming to improve its ability to bridge the gap between code and comments and to focus on code elements at different granularities. Experimental results demonstrate that CCIHunter achieves a precision of 0.95, a recall of 0.90, and an F1 score of 0.93, outperforming existing tools.

This article proposes an intermittent optimal learning control strategy for nonlinear discrete-time systems under time-varying pass lengths and actuator faults. The target of the problem is to minimize the timewise tracking error and the input drifts, which are combined by a time-iteration-dependent factor. By searching the nearest available pass at each time instant for the current iteration, the optimal control gain can be obtained. Theoretical analysis indicates that the tracking error converges asymptotically in spite of the actuator fault and the robustness against the shifted initial state is further proven. Numerical simulations illustrate the effectiveness and robustness of the presented method.

Web3 describes an idea for the next evolution of the Internet, where blockchain technology enables the Internet of Value. As Web3 software, decentralized applications (DApps) have emerged in recent years. There exists a natural link between DApps and cryptocurrencies, where faults in DApps could directly lead to monetary losses associated with cryptocurrencies. Hence, efficient fault localization technology is of paramount importance for urgent DApp rescue operations and the mitigation of financial losses. However, fault localization methods applied in traditional applications are not well-suited for this specific field, due to their inability to identify DApp-specific fault features, e.g., a substantial amount of cryptocurrency is transferred from DApps to hackers. In order to explore the root cause of DApp faults, some researchers try to identify suspicious code snippets through mutation testing. Nonetheless, applying mutation testing for DApp fault localization is time-consuming and thus limited in practice. This paper conducts the first comprehensive study of DApp fault localization. We introduce DAppFL, a learning-based DApp fault localization tool that performs reverse engineering to gather executed source code and then trace cryptocurrency flow to assist in locating faulty functions. We also present the inaugural dataset for DApp fault localization, providing a new benchmark for this domain.Our experimental results demonstrate that DAppFL locates 63% of faults within the Top-5, 23% more than the state-of-the-art method. To facilitate further research, our code and dataset are freely available online: https://github.com/xplanet-sysu/awesome-works#dappfl.

With the rapid development of 6G networks and artificial intelligence of things(AIoT), the volume of generated data has surged exponentially. Deep Compressed sensing(DCS) achieve accurate data reconstruction at Sub-Nyquist rates, minimizing data transmission volume and optimizing performance in unimodal vision tasks. However, given the substantial memory and computational resources required, deploying these DCS models on resource-constrained edge devices and executing dynamic training poses formidable challenges. Additionally, cloud-based processing introduces privacy vulnerabilities and potential performance degradation. This paper introduces a ConvMixed-ViT architecture based on Low-Rank Adaptation (LoRA) and employs an end-to-end methodology integrating learnable CS to facilitate compression and precise reconstruction on edge environments. Specifically, the LoRA freezes pre-trained model weights and injects them into the ConvMixed-ViT Architecture's Transformer variant framework through trainable rank decomposition matrices, greatly reducing the number of trainable parameters for downstream tasks and controlling the model size. The experimental results demonstrate that our proposed architecture achieves excellent reconfiguration performance on standard benchmark datasets. In resource-limited environments, CTLCS offers efficient adaptability and optimizes performance, proving its suitability for future edge AI applications.

Stimulation to local areas remarkably affects brain activity patterns, which can be exploited to investigate neural bases of cognitive function and modify pathological brain statuses. There has been growing interest in exploring the fundamental action mechanisms of local stimulation. Nevertheless, how noise amplitude, an essential element in neural dynamics, influences stimulation-induced brain states remains unknown. Here, we systematically examine the effects of local stimulation by using a large-scale biophysical model under different combinations of noise amplitudes and stimulation sites. We demonstrate that noise amplitude nonlinearly and heterogeneously tunes the stimulation effects from both regional and network perspectives. Furthermore, by incorporating the role of the anatomical network, we show that the peak frequencies of unstimulated areas at different stimulation sites averaged across noise amplitudes are highly positively related to structural connectivity. Crucially, the association between the overall changes in functional connectivity as well as the alterations in the constraints imposed by structural connectivity with the structural degree of stimulation sites is nonmonotonically influenced by the noise amplitude, with the association increasing in specific noise amplitude ranges. Moreover, the impacts of local stimulation of cognitive systems depend on the complex interplay between the noise amplitude and average structural degree. Overall, this work provides theoretical insights into how noise amplitude and network structure jointly modulate brain dynamics during stimulation and introduces possibilities for better predicting and controlling stimulation outcomes.

In this work, we explore the learning task of mixtures of Markov chains (MMCs) from aggregate data. Our work demonstrates that although this challenging task is generally intractable because of the identifiability problem, it can be solved approximately by imposing structural constraints on its transition matrices Specifically, the proposed structural constraints include specifying active state sets corresponding to the chains and adding a series of pairwise sparse regularizers on transition matrices. Based on these two structural constraints, we propose a constrained least-squares method to learn mixtures of Markov chains. We develop a novel iterative algorithm that decomposes the overall problem into a set of convex subproblems and solves each subproblem efficiently. Experimental results on synthetic data prove that our learning method converges well and is robust to the noise in data. Moreover, the comparison with state-of-art competitors on real-world data further validates the superiority of our method.

In recent years, multimedia retrieval has sparked much research interest in the multimedia, pattern recognition, and data mining communities. Although some attempts have been made along this direction, performing fast multimodal search at very large scale still remains a major challenge in the area. While hashing-based methods have recently achieved promising successes in speeding-up large-scale similarity search, most existing methods are only designed for uni-modal data, making them unsuitable for multimodal multimedia retrieval. In this paper, we propose a new hashing-based method for fast multimodal multimedia retrieval. The method is based on spectral analysis of the correlation matrix of different modalities. We also develop an efficient algorithm that learns some parameters from the data distribution for obtaining the binary codes. We empirically compare our method with some state-of-the-art methods on two real-world multimedia data sets.

Multi-modal similarity search has attracted considerable attention to meet the need of information retrieval across different types of media. To enable efficient multi-modal similarity search in large-scale databases recently, researchers start to study multi-modal hashing. Most of the existing methods are applied to search across multi-views among which explicit correspondence is provided. Given a multi-modal similarity search task, we observe that abundant multi-view data can be found on the Web which can serve as an auxiliary bridge. In this paper, we propose a Heterogeneous Translated Hashing (HTH) method with such auxiliary bridge incorporated not only to improve current multi-view search but also to enable similarity search across heterogeneous media which have no direct correspondence. HTH provides more flexible and discriminative ability by embedding heterogeneous media into different Hamming spaces, compared to almost all existing methods that map heterogeneous data in a common Hamming space. We formulate a joint optimization model to learn hash functions embedding heterogeneous media into different Hamming spaces, and a translator aligning different Hamming spaces. The extensive experiments on two real-world datasets, one publicly available dataset of Flickr, and the other MIRFLICKR-Yahoo Answers dataset, highlight the effectiveness and efficiency of our algorithm.

Statistical models based on Markov chains, especially mixtures of Markov chains, have recently been studied and demonstrated to be effective in various data mining applications such as tourist flow analysis, animal migration modeling, and transportation administration. Nevertheless, the research so far has mainly focused on analyzing data at individual levels. Due to security and privacy reasons, however, the observations in practice usually consist of coarse-grained statistics of individual data,a.k.a.aggregate data, rendering learning mixtures of Markov chains an even more challenging problem. In this work, we show that this challenging problem, although intractable in its original form, can be solved approximately by posing structural constraints on the transition matrices. The proposed structural constraints include specifying active state sets corresponding to the chains and adding a pairwise sparse regularization term on transition matrices. Based on these two structural constraints, we propose a constrained least-squares method to learn mixtures of Markov chains. We further develop a novel iterative algorithm that decomposes the overall problem into a set of convex subproblems and solves each subproblem efficiently, making it possible to effectively learn mixtures of Markov chains from aggregate data. We propose a framework for generating synthetic data and analyze the complexity of our algorithm. Additionally, the empirical results of the convergence and the robustness of our algorithm are also presented. These results demonstrate the effectiveness and efficiency of the proposed algorithm, comparing with traditional methods. Experimental results on real-world data sets further validate that our algorithm can be used to solve practical problems.

In recent years, we have witnessed the boom of social media platforms, through which people have been generating a lot of social media data. This data touches almost every aspect of life and may have significant societal and marketing values for a variety of corporations and organizations. Thus, the development of effective techniques for gathering and analyzing social media content has attracted much research attention. As social media data tend to be heterogeneous, conversational, and fast evolving in content, a recent work reported a multifaceted approach to gather comprehensive brand-related data by crawling data using evolving keywords, key users, similar image content, and known locations. Although such approach has been found to be effective in gathering representative data, it also brings in a lot of noise. This paper aims to develop an accurate classifier to filter out noise by taking into account the multimedia content and social nature of brand-related data. In particular, we develop a microblog filtering method based on a discriminative social-aware multiview embedding. Besides the conventional content-based features, such as textual, low-level visual features, and high-level visual semantic features, that form the three key views of microblogs, we also incorporate the brand and social relations among the microblogs to learn a discriminative and social-aware embedding. With such a learned embedding, an off-the-shelf classifier, such as SVM, can then be trained and applied to microblog filtering. We verify the efficacy of our method on noise filtering in the brand data gathering task on the Brand-Social-Net dataset. Our approach is able to achieve significantly better filtering performance and improve the quality of brand data gathering.

We present a probabilistic framework for learning pairwise similarities between objects belonging to different modalities, such as drugs and proteins, or text and images. Our framework is based on learning a binary code based representation for objects in each modality, and has the following key properties: (i) it can leverage both pairwise as well as easy-to-obtain relative preference based cross-modal constraints, (ii) the probabilistic framework naturally allows querying for the most useful/informative constraints, facilitating an active learning setting (existing methods for cross-modal similarity learning do not have such a mechanism), and (iii) the binary code length is learned from the data. We demonstrate the effectiveness of the proposed approach on two problems that require computing pairwise similarities between cross-modal object pairs: cross-modal link prediction in bipartite graphs, and hashing based cross-modal similarity search.

The rapid spreading of RGB-D cameras has led to wide applications of 3D videos in both academia and industry, such as 3D entertainment and 3D visual understanding. Under these circumstances, extensive research efforts have been dedicated to RGB-D camera--oriented topics. In these topics, quality promotion of depth videos with the temporal characteristic is emerging and important. Due to the limited exposure time of RGB-D cameras, object movement can easily lead to motion blurs in intensive images, which can further result in obvious artifacts (holes or fake boundaries) in the corresponding depth frames. With regard to this problem, we propose a depth error elimination method based on time series analysis to remove the artifacts in depth images. In this method, we first locate the regions with erroneous depths in intensive images by using motion blur detection based on a time series analysis model. This is based on the fact that the depth image is calculated by intensive color images that are captured synchronously by RGB-D cameras. Then, the artifacts, such as holes or fake boundaries, are fixed by a depth error elimination method. To evaluate the performance of the proposed method, we conducted experiments on 250 images. Experimental results demonstrate that the proposed method can locate the error regions correctly and eliminate these artifacts effectively. The quality of depth video can be improved significantly by using the proposed method.

Hashing has enjoyed a great success in large-scale similarity search. Recently, researchers have studied the multi-modal hashing to meet the need of similarity search across different types of media. However, most of the existing methods are applied to search across multi-views among which explicit bridge information is provided. Given a heterogeneous media search task, we observe that abundant multi-view data can be found on the Web which can serve as an auxiliary bridge. In this paper, we propose a Heterogeneous Translated Hashing (HTH) method with such auxiliary bridge incorporated not only to improve current multi-view search but also to enable similarity search across heterogeneous media which have no direct correspondence. HTH simultaneously learns hash functions embedding heterogeneous media into different Hamming spaces, and translators aligning these spaces. Unlike almost all existing methods that map heterogeneous data in a common Hamming space, mapping to different spaces provides more flexible and discriminative ability. We empirically verify the effectiveness and efficiency of our algorithm on two real world large datasets, one publicly available dataset of Flickr and the other MIRFLICKR-Yahoo Answers dataset.

In recent years, both hashing-based similarity search and multimodal similarity search have aroused much research interest in the data mining and other communities. While hashing-based similarity search seeks to address the scalability issue, multimodal similarity search deals with applications in which data of multiple modalities are available. In this paper, our goal is to address both issues simultaneously. We propose a probabilistic model, called multimodal latent binary embedding (MLBE), to learn hash functions from multimodal data automatically. MLBE regards the binary latent factors as hash codes in a common Hamming space. Given data from multiple modalities, we devise an efficient algorithm for the learning of binary latent factors which corresponds to hash function learning. Experimental validation of MLBE has been conducted using both synthetic data and two realistic data sets. Experimental results show that MLBE compares favorably with two state-of-the-art models.

Hashing-based methods provide a very promising approach to large-scale similarity search. To obtain compact hash codes, a recent trend seeks to learn the hash functions from data automatically. In this paper, we study hash function learning in the context of multimodal data. We propose a novel multimodal hash function learning method, called Co-Regularized Hashing (CRH), based on a boosted co-regularization framework. The hash functions for each bit of the hash codes are learned by solving DC (difference of convex functions) programs, while the learning for multiple bits proceeds via a boosting procedure so that the bias introduced by the hash functions can be sequentially minimized. We empirically compare CRH with two state-of-the-art multimodal hash function learning methods on two publicly available data sets.

In recent years, active learning methods based on experimental design achieve state-of-the-art performance in text classification applications. Although these methods can exploit the distribution of unlabeled data and support batch selection, they cannot make use of labeled data which often carry useful information for active learning. In this paper, we propose a novel active learning method for text classification, called supervised experimental design (SED), which seamlessly incorporates label information into experimental design. Experimental results show that SED outperforms its counterparts which either discard the label information even when it is available or fail to exploit the distribution of unlabeled data.

Besides the rating information, an increasing number of modern recommender systems also allow the users to add personalized tags to the items. Such tagging information may provide very useful information for item recommendation, because the users' interests in items can be implicitly reflected by the tags that they often use. Although some content-based recommender systems have made preliminary attempts recently to utilize tagging information to improve the recommendation performance, few recommender systems based on collaborative filtering (CF) have employed tagging information to help the item recommendation procedure. In this paper, we propose a novel framework, called tag informed collaborative filtering (TagiCoFi), to seamlessly integrate tagging information into the CF procedure. Experimental results demonstrate that TagiCoFi outperforms its counterpart which discards the tagging information even when it is available, and achieves state-of-the-art performance.