With the rapid development of 6 G communication technology and the Internet of Things (IoT), mobile edge computing (MEC) is regarded as an effective paradigm of providing low-delay, high-quality services to mobile users. In the IoT device-edge-cloud network, the optimal deployment of MEC servers is a prerequisite for a better task offloading, while the improved performance of mobile users task offloading also indicates the deployment scheme is optimal. Most of current MEC servers deployment studies focus on reducing delay and deployment costs, but ignore the offloading requirements of mobile users with similar task type and cooperative relationship arriving at the same community. In this paper, we study the MEC servers deployment driven by the task offloading requirements of community mobile users in current period by utilizing the stability of their social cooperative relationships to maximize the service satisfaction of all community mobile users in the future task offloading. First, the cooperative relationship strength between mobile users is measured to form a group of resource requesters based on interaction probability, movement trajectory and credit strength. Then, we implement the optimal search of base stations (BSs) using spatial index, followed by the one-to-many matching theory between BSs and community group resource requesters, to balance the load of BSs and reduce the communication delay between them. Finally, we use TD($\lambda$) algorithm and task similarity between cooperative users to deploy MEC servers with suitable resources around BSs so that the deployment scheme can significantly improve the future task offloading performance of all community mobile users. Based on the real data set provided by Shanghai Telecom, it is confirmed that the proposed scheme has significant advantages in improving all community mobile users service satisfaction, with an average improvement of 18.49% compared with the baselines.

Mobile Edge Computing (MEC) and Device-toDevice (D2D) peer offloading are two promising paradigms in the mobile Internet of Things (IoT). In this paper, we study the collaborative task offloading with redundant data and codes in large-scale IoT networks, where computing resource-starved IoT devices can offload their tasks to MEC servers via cellular links or to nearby peer devices (PDs) with idle resources through D2D links for execution. IoT tasks usually consist of a series of dependent and parallel subtasks, and the difficulties in current research are (i) how to eliminate redundancy in data or codes between subtasks, and (ii) how to leverage previous experience to adaptively search a set of collaborative MEC servers and PDs for matching offloading of dependent and parallel subtasks. From this, we propose a redundancy-aware adaptive search offloading (RASO) method based on the deep Q-network (DQN). Specifically, we first design a fine-grained task recombination scheme by judging the consistency of subtask data and codes. After that, we organize the global devices into a spatial index MP-tree to reduce the search solution space, and propose a fast adaptive search method based on the DQN combined with MP-tree, where optimal path-guiding parameters training of inner and outer layers is involved to efficiently help achieve collaborative devices to complete specific tasks with the same type. After finding the collaborative MEC servers and PDs along MP-tree for a certain task, a centralized stable matching algorithm is further developed to give a decision of offloading each of its divided dependent and parallel subtasks to the matched one, thereby optimizing offloading delay and energy consumption. Extensive simulation results show that compared to other counterpart solutions, our proposed method has improved task offloading performance in terms of delay and energy consumption.

Accurate decoding in electroencephalography (EEG) technology, particularly for rapid visual stimuli, remains challenging due to the low signal-to-noise ratio (SNR). Additionally, existing neural networks struggle with issues related to generalization and interpretability. This article proposes a cross-modal aligned network, E2IVAE, which leverages shared information from multiple modalities for self-supervised alignment of EEG to images for extracting visual perceptual information and features a novel EEG encoder, ISTANet, based on algorithm unrolling. This network framework significantly enhances the accuracy and stability of EEG decoding for object recognition in novel classes while reducing the extensive neural data typically required for training neural decoders. The proposed ISTANet employs algorithm unrolling to transform the multilayer sparse coding algorithm into an end-to-end format, extracting features from noisy EEG signals while incorporating the interpretability of traditional machine learning. The experimental results demonstrate that our method achieves SOTA top-1 accuracy of 62.39% and top-5 accuracy of 88.98% on a comprehensive rapid serial visual presentation (RSVP) dataset for public comparison in a 200-class zero-shot neural decoding task. Additionally, ISTANet enables visualization and analysis of multiscale atom features and overall reconstruction features, exploring biological plausibility across temporal, spatial, and spectral dimensions. On another more challenging RSVP large-scale dataset, the proposed framework also achieves significantly above chance-level performance, proving its robustness and generalization. This research provides critical insights into neural decoding and brain-computer interfaces (BCIs) within the fields of cognitive science and artificial intelligence.

Although the negative impact of abbreviations in source code is well-recognized, abbreviations are common for various reasons. To this end, a number of approaches have been proposed to expand abbreviations in identifiers. However, such approaches are either inaccurate or confined to specific identifiers. To this end, in this paper, we propose a generic and accurate approach to expand identifier abbreviations by leveraging both semantic relation and transfer expansion. One of the key insights of the approach is that abbreviations in the name of software entity$e$have a great chance to find their full terms in names of software entities that are semantically related to$e$. Consequently, the proposed approach builds a knowledge graph to represent such entities and their relationships with$e$and searches the graph for full terms. Another key insight is that literally identical abbreviations within the same application are likely (but not necessary) to have identical expansions, and thus the semantics-based expansion in one place may be transferred to other places. To investigate when abbreviation expansion could be transferred safely, we conduct a case study on three open-source applications. The results suggest that a significant part (75 percent) of expansions could be transferred among lexically identical abbreviations within the same application. However, the risk of transfer varies according to various factors, e.g., length of abbreviations, the physical distance between abbreviations, and semantic relations between abbreviations. Based on these findings, we design nine heuristics for transfer expansion and propose a learning-based approach to prioritize both transfer heuristics and semantic-based expansion heuristics. Evaluation results on nine open-source applications suggest that the proposed approach significantly improves the state of the art, improving recall from 29 to 89 percent and precision from 39 to 92 percent.

Code smells are structures in the source code that suggest the possibility of refactorings. Consequently, developers may identify refactoring opportunities by detecting code smells. However, manual identification of code smells is challenging and tedious. To this end, a number of approaches have been proposed to identify code smells automatically or semi-automatically. Most of such approaches rely on manually designed heuristics to map manually selected source code metrics into predictions. However, it is challenging to manually select the best features. It is also difficult to manually construct the optimal heuristics. To this end, in this paper we propose a deep learning based novel approach to detecting code smells. The key insight is that deep neural networks and advanced deep learning techniques could automatically select features of source code for code smell detection, and could automatically build the complex mapping between such features and predictions. A big challenge for deep learning based smell detection is that deep learning often requires a large number of labeled training data (to tune a large number of parameters within the employed deep neural network) whereas existing datasets for code smell detection are rather small. To this end, we propose an automatic approach to generating labeled training data for the neural network based classifier, which does not require any human intervention. As an initial try, we apply the proposed approach to four common and well-known code smells, i.e., feature envy, long method, large class, and misplaced class. Evaluation results on open-source applications suggest that the proposed approach significantly improves the state-of-the-art.

When users encounter problems with mobile apps, they may commit such problems to developers as bug reports. To facilitate the processing of bug reports, researchers proposed approaches to validate the reported issues automatically according to the steps to reproduce specified in bug reports. Although such approaches have achieved high success rate in reproducing the reported issues, they often rely on a predefined vocabulary to identify and classify actions in bug reports. However, such manually constructed vocabulary and classification have significant limitations. It is challenging for the vocabulary to cover all potential action words because users may describe the same action with different words. Besides that, classification of actions solely based on the action words could be inaccurate because the same action word, appearing in different contexts, may have different meaning and thus belongs to different action categories. To this end, in this paper we propose an automated approach, called MaCa, to identify and classify action words in Mobile apps’ bug reports. For a given bug report, it first identifies action words based on natural language processing. For each of the resulting action words, MaCa extracts its contexts, i.e., its enclosing segment, the associated UI target, and the type of its target element by both natural language processing and static analysis of the associated app. The action word and its contexts are then fed into a machine learning based classifier that predicts the category of the given action word in the given context. To train the classifier, we manually labelled 1,202 actions words from 525 bug reports that are associated with 207 apps. Our evaluation results on manually labelled data suggested that MaCa was accurate with high accuracy varying from 95% to 96.7%. We also investigated to what extent MaCa could further improve existing approaches (i.e., Yakusu and ReCDroid) in reproducing bug reports. Our evaluation results suggested that integrating MaCa into existing approaches significantly improved the success rates of ReCDroid and Yakusu by 22.7% = (69.2%-56.4%)/56.4% and 22.9%= (62.7%-51%)/51%, respectively.

Identifiers in source code are composed of terms in natural languages. Such terms, as well as phrases composed of such terms, convey rich semantics that could be exploited for program analysis and comprehension. To this end, in this paper we propose a deep learning based approach, called MLDetector, to identifying suspicious return statements by leveraging semantics conveyed by the natural language phrases that are used as identifiers in the source code. We specially design a deep neural network to tell whether a given return statement matches its corresponding method signature. The rationale is that both method signature and return value should explicitly specify the output of the method, and thus a significant mismatch between method signature and return value may suggest a suspicious return statement. To address the challenge of lacking negative training data, i.e., incorrect return statements, we generate negative training data automatically by transforming real-world correct return statements. To feed code into neural network, we convert them into vectors by Word2Vec, an unsupervised neural network based learning algorithm. We evaluate the proposed approach in two parts. In the first part, we evaluate it on 500 open-source applications by automatically generating labeled training data. Results suggest that the precision of the proposed approach varies from 83% to 90%. In the second part, we conduct a case study on 100 real-world applications. Evaluation results suggest that 42 out of 65 real-world incorrect return statements are detected (with precision of 59%).