Presently, it is still challenging to obtain satisfied identification results for long-distance safety monitoring with fiber distributed acoustic sensor (DAS) in practical complicated burying environments. Thus, extracting increasingly abundant features has always been the direction of DAS signal recognition. This paper proposes a new recognition method using an end-to-end mCNN-HMM combined model, which can identify the vibration sources more correctly by simultaneously extracting multi-scale structural features and the sequential information of the DAS signals. A modified multi-scale convolution neural network (mCNN) is designed to automatically extract the DAS signals' local structural features from a multilevel perspective and their relationship in the proposed model. A hidden Markov model (HMM) is then used to mine the sequential information of the whole sample's previously extracted features. The test results based on real field data show that it outperforms the HMM model with the all-around hand-crafted features, the CNN-HMM model, and the MS-CNN-HMM model in both the feature extraction ability and the recognition accuracy in the case of little increase in time consumption. Moreover, the Euclidean distance between the posterior probabilities classified correctly and incorrectly is proposed to evaluate the test samples' feature distinguishability for different recognition models. Then the feature extraction capabilities of the models can be measured in an objective parameter.

Sensor drift is a common issue in E-Nose systems and various drift compensation methods have received fruitful results in recent years. Although the accuracy for recognizing diverse gases under drift conditions has been largely enhanced, few of these methods considered online processing scenarios. In this paper, we focus on building online drift compensation model by transforming two domain adaptation based methods into their online learning versions, which allow the recognition models to adapt to the changes of sensor responses in a time-efficient manner without losing the high accuracy. Experimental results using three different settings confirm that the proposed methods save large processing time when compared with their offline versions, and outperform other drift compensation methods in recognition accuracy.

This paper mainly deals with how kernel method can be used for software defect prediction, since the class imbalance can greatly reduce the performance of defect prediction. In this paper, two classifiers, namely, the asymmetric kernel partial least squares classifier (AKPLSC) and asymmetric kernel principal component analysis classifier (AKPCAC), are proposed for solving the class imbalance problem. This is achieved by applying kernel function to the asymmetric partial least squares classifier and asymmetric principal component analysis classifier, respectively. The kernel function used for the two classifiers is Gaussian function. Experiments conducted on NASA and SOFTLAB data sets usingF-measure, Friedman’s test, and Tukey’s test confirm the validity of our methods.

As one of the most popular consumer electronics, Unmanned Aerial Vehicle (UAV) has the potential to assist User Equipment (UE) in the Internet of Everything. Mobile edge computing (MEC) is also an emerging technique that can provide sufficient computing resources to IoE users. In this paper, we focused on the UAV-assisted MEC problem with mobile UEs, where the UAV serves as an MEC server to assist UEs in computing and acts as a relay to deliver tasks to a ground access point (AP). The objective is to minimize the average time for completing all tasks in the network while jointly optimizing resource allocation such as communication bandwidth, CPU frequency, task division ratio, and UAV’s three-dimensional location deployment. First, we proposed an online MEC network adjustment scheme. Then, we decomposed the formulated non-convex problem into three low-complexity subproblems. Last, we proposed a successive convex approximation-based joint optimization algorithm to solve them. In addition, we presented heuristic conclusions in task allocation rules, UAV flight trajectory prediction, and UAV hovering altitude selection, which can further reduce task completion time and deepen the understanding of the working mode of mobile edge servers. Simulation results show that the algorithm can significantly reduce the completion time.