Driven by the popularity of the Android system, Android app markets enjoy a booming prosperity in recent years. One critical problem for modern Android app markets is how to prevent apps that are going to receive low ratings from reaching end users. For this purpose, traditional approaches have to publish an app first and then collect enough user ratings and reviews so as to determine whether the app is favored by end users or not. In this way, however, the reputation of the app market has already been damaged. To address this problem, we propose a novel technique, i.e., Sextant , to detect low rating Android apps based on the .apk files.With our proposed technique, an Android app market can prevent from risking its reputation on exposing low rating apps to users. Sextant is developed based on novel static analysis techniques as well as machine learning techniques. In our study, our proposed approach can achieve on average 90.50 precision and 94.31 recall.
@cite_47: Software defect prediction, which predicts defective code regions, can help developers find bugs and prioritize their testing efforts. To build accurate prediction models, previous studies focus on manually designing features that encode the characteristics of programs and exploring different machine learning algorithms. Existing traditional features often fail to capture the semantic differences of programs, and such a capability is needed for building accurate prediction models. To bridge the gap between programs' semantics and defect prediction features, this paper proposes to leverage a powerful representation-learning algorithm, deep learning, to learn semantic representation of programs automatically from source code. Specifically, we leverage Deep Belief Network (DBN) to automatically learn semantic features from token vectors extracted from programs' Abstract Syntax Trees (ASTs). Our evaluation on ten open source projects shows that our automatically learned semantic features significantly improve both within-project defect prediction (WPDP) and cross-project defect prediction (CPDP) compared to traditional features. Our semantic features improve WPDP on average by 14.7 in precision, 11.5 in recall, and 14.2 in F1. For CPDP, our semantic features based approach outperforms the state-of-the-art technique TCA+ with traditional features by 8.9 in F1.
Wang and colleagues proposed a neural network based approach for defect prediction on the source code file level @cite_47 . This approach first encodes programs based on the token vector of AST nodes. Then it uses a deep belief network for feature dimension reduction. Finally, it trains a model to classify buggy files with the features with reduced dimension. This technique cannot be directly used to detect low rating apps because of two reasons. First, it requires source code. Second, the size of the token vector can be too large for machine learning models on the whole application level.