Bug or Not? Bug Report Classification Using N-Gram IDF

Previous studies have found that a significant number of bug reports are misclassified between bugs and non-bugs, and that manually classifying bug reports is a time-consuming task. To address this problem, we propose a bug reports classification model with N-gram IDF, a theoretical extension of Inverse Document Frequency (IDF) for handling words and phrases of any length. N-gram IDF enables us to extract key terms of any length from texts, these key terms can be used as the features to classify bug reports. We build classification models with logistic regression and random forest using features from N-gram IDF and topic modeling, which is widely used in various software engineering tasks. With a publicly available dataset, our results show that our N-gram IDF-based models have a superior performance than the topic-based models on all of the evaluated cases. Our models show promising results and have a potential to be extended to other software engineering tasks.Comment: 5 pages, ICSME 201

Initial B Cell Activation Induces Metabolic Reprogramming and Mitochondrial Remodeling.

B lymphocytes provide adaptive immunity by generating antigen-specific antibodies and supporting the activation of T cells. Little is known about how global metabolism supports naive B cell activation to enable an effective immune response. By coupling RNA sequencing (RNA-seq) data with glucose isotopomer tracing, we show that stimulated B cells increase programs for oxidative phosphorylation (OXPHOS), the tricarboxylic acid (TCA) cycle, and nucleotide biosynthesis, but not glycolysis. Isotopomer tracing uncovered increases in TCA cycle intermediates with almost no contribution from glucose. Instead, glucose mainly supported the biosynthesis of ribonucleotides. Glucose restriction did not affect B cell functions, yet the inhibition of OXPHOS or glutamine restriction markedly impaired B cell growth and differentiation. Increased OXPHOS prompted studies of mitochondrial dynamics, which revealed extensive mitochondria remodeling during activation. Our results show how B cell metabolism adapts with stimulation and reveals unexpected details for carbon utilization and mitochondrial dynamics at the start of a humoral immune response