Biblio

The humidity in the air parameters has an impact on the characteristics of corona discharge, and the magnetic field also affects the electron movement of corona discharge. We build a constant humidity chamber and use a wire-mesh electrode device to study the effects of humidity and magnetic field on the discharge. The enhancement of the discharge by humidity is caused by the combination of water vapor molecules and ions generated by the discharge into hydrated ions. By building a “water flow channel” between the high voltage wire electrode and the ground mesh electrode, the ions can pass more smoothly, thereby enhanced discharge. The ions are subjected to the Lorentz force in the electromagnetic field environment, the motion state of the ions changes, and the larmor motion in the electromagnetic field increases the movement path, the collision between the gas molecules increases, and more charged particles are generated, which increases the discharge current. During the period, the electrons and ions generated by the ionization of the wire electrode leave the ionization zone faster, which reduces the inhibitory effect of the ion aggregation on the discharge and promotes the discharge.

Vulnerabilities in the source code of software are critical issues in the realm of software engineering. Coping with vulnerabilities in software source code is becoming more challenging due to several aspects of complexity and volume. Deep learning has gained popularity throughout the years as a means of addressing such issues. In this paper, we propose an evaluation of vulnerability detection performance on source code representations and evaluate how Machine Learning (ML) strategies can improve them. The structure of our experiment consists of 3 Deep Neural Networks (DNNs) in conjunction with five different source code representations; Abstract Syntax Trees (ASTs), Code Gadgets (CGs), Semantics-based Vulnerability Candidates (SeVCs), Lexed Code Representations (LCRs), and Composite Code Representations (CCRs). Experimental results show that employing different ML strategies in conjunction with the base model structure influences the performance results to a varying degree. However, ML-based techniques suffer from poor performance on class imbalance handling when used in conjunction with source code representations for software vulnerability detection.

Ahstract-Vulnerability detection is an important topic of software engineering. To improve the effectiveness and efficiency of vulnerability detection, many traditional machine learning-based and deep learning-based vulnerability detection methods have been proposed. However, the impact of different factors on vulnerability detection is unknown. For example, classification models and vectorization methods can directly affect the detection results and code replacement can affect the features of vulnerability detection. We conduct a comparative study to evaluate the impact of different classification algorithms, vectorization methods and user-defined variables and functions name replacement. In this paper, we collected three different vulnerability code datasets. These datasets correspond to different types of vulnerabilities and have different proportions of source code. Besides, we extract and analyze the features of vulnerability code datasets to explain some experimental results. Our findings from the experimental results can be summarized as follows: (i) the performance of using deep learning is better than using traditional machine learning and BLSTM can achieve the best performance. (ii) CountVectorizer can improve the performance of traditional machine learning. (iii) Different vulnerability types and different code sources will generate different features. We use the Random Forest algorithm to generate the features of vulnerability code datasets. These generated features include system-related functions, syntax keywords, and user-defined names. (iv) Datasets without user-defined variables and functions name replacement will achieve better vulnerability detection results.