基于循环神经网络的缺陷报告分派方法

随着开源软件项目规模的不断增大,人工为缺陷报告分派合适的开发人员（缺陷分派）变得越来越困难.而不合适的缺陷分派往往会严重影响缺陷修复的效率,为此迫切需要一种缺陷分派辅助技术帮助项目管理者更好地完成缺陷分派任务.当前,大部分研究工作都基于缺陷报告文本以及相关元数据信息分析来刻画开发者的特征,忽略了对开发者活跃度的考虑,使得对具有相似特征的开发者进行缺陷报告分派预测时表现较差.本文提出了一个基于循环神经网络的深度学习模型DeepTriage,一方面利用双向循环网络加池化方法提取缺陷报告的文本特征,一方面利用单向循环网络提取特定时刻的开发者活跃度特征,并融合两者,利用已修复的缺陷报告进行监督学习.在Eclipse等四个不同的开源项目数据集上的实验结果表明,DeepTriage较同类工作在缺陷分派预测准确率上有显著提升.     

知识驱动的相似缺陷报告推荐方法

软件缺陷在软件开发过程中不可避免,提交的缺陷报告则是分析和修复缺陷的重要信息来源。开发人员常通过借鉴相似的历史缺陷报告和修复信息来辅助对当前新缺陷的分析和修复。文中提出了一种知识驱动的相似缺陷报告推荐方法。该方法首先利用信息检索和Word Embedding技术构建缺陷知识图谱;然后利用TF-IDF和Word Embedding技术计算缺陷报告之间的文本相似度,同时综合考虑缺陷的各项属性,从而得到缺陷报告之间的主次要属性相似度;最后将上述相似度融合成综合相似度,利用综合相似度推荐相似缺陷报告。实验结果表明,与基线方法相比,在Firefox数据集上所提方法的性能平均提高了12.7%。     

基于多头自注意力机制的深度缺陷分派模型

当前,缺陷跟踪系统通过缺陷报告实现缺陷与修复者的匹配。然而,以往的缺陷分派模型过于依赖缺陷报告的文本质量,引入自然语言中大量的冗余信息,并忽略了缺陷报告的元字段作为标签属性时存在于修复者之间的社区关系,使得模型结果表现较差。针对以上问题,本文提出一种基于多头自注意力机制的深度缺陷分派模型MSDBT(Multi-head Self-attention Deep Bug Triage)。对缺陷报告的文本内容以及根据元字段生成的修复者序列进行向量化;通过多头自注意力机制在内部的输入元素之间进行并行注意力计算。在4个开源软件项目上的实验结果表明,MSDBT在召回率指标上较之前模型具有明显的优势。     

OSDR:一种开源软件的缺陷修复人推荐方法

对于大型开源软件项目来说,用户提交了海量缺陷报告,人工分发缺陷时会出现大量的错误分配。提出OSDR(Open Software Developer Recommendation)方法通过计算新缺陷报告和历史缺陷报告之间的文本相似度,基于K最近邻算法得到相似度最高的K个历史缺陷报告及其对应的修复人列表,再基于频率和社交网络图的各项指标对开发者专业能力进行评价。从Mozilla Firefox缺陷库中采集真实实验数据,比较不同社交网络指标在推荐修复人时的准确率与召回率。结果表明,推荐性能最高的指标是频率和出度,其准确率大约在0.6左右;Betweenness和Closeness的推荐效果最差;度、入度以及PageRank推荐效果良好。     

自动分析软件缺陷报告间相关性的方法研究*

针对缺陷报告相关性分析的研究主要采用计算其文本信息相似度的方法使其查全率和查准率并不理想,提出了一种将结构化信息相似度与文本信息相似度计算相结合的方法,即同时提取出缺陷报告中的文本信息（包括主题和详细描述）以及结构化信息（包括补丁、异常堆栈和代码片段）,从缺陷外部表现和内部特征两个角度共同衡量缺陷报告间的相关性。通过对Eclipse系统中的1 000个缺陷报告进行实验,结果显示,增加结构化信息相似度计算,可以有效地将缺陷报告间相关性分析的查准率和查全率均提高到90%左右。     

一种基于文本分类和评分机制的软件缺陷分配方法

开源软件项目的缺陷管理和修复是保障软件质量及软件开发效率的重要手段,而提高软件缺陷分配的效率是其中亟需解决的一个关键问题。文中提出了一种基于文本分类和评分机制的开发者预测方法,其核心思想是综合考虑基于机器学习的文本分类和基于软件缺陷从属特征的评分机制来构建预测模型。针对大型开源软件项目Eclipse和Mozilla的十万级已修复软件缺陷的实验表明,在“十折”增量验证模式下,所提方法的最好平均准确率分别达到了78.39%和64.94%,比基准方法(机器学习分类+再分配图)的最高平均准确率分别提升了17.34%和10.82%,从而验证了其有效性。     

基于缺陷修复历史的两阶段缺陷定位方法

缺陷定位是软件缺陷修复的关键步骤。随着计算机软件的日趋复杂和网络的迅速发展,如何快速高效的定位缺陷相关代码成为了一个急待解决的问题。在研究现有基于信息检索技术的缺陷定位方法的基础上,综合考虑缺陷修复历史信息,提出了基于缺陷修复历史的两阶段缺陷定位方法。该方法不再单一依赖文本相似度,从缺陷修复的局部性现象入手,更多的考虑了缺陷修复的历史记录、变更信息及代码特征等因素,结合信息检索和缺陷预测方法来提高缺陷定位的精度。最后本文以两个开源项目为例,验证了方法的可行性和有效性。     

深度学习在缺陷修复者推荐中的应用

目前许多软件项目使用缺陷追踪系统来自动化管理用户或者开发人员提交的缺陷报告。随着缺陷报告和开发人员数量的增长,如何快速将缺陷报告分配给合适的缺陷修复者正在成为缺陷快速解决的一个重要问题。分别使用长短期记忆模型和卷积神经网络两种深度学习方法来构建缺陷修复者推荐模型。该模型能够有效地学习缺陷报告的特征,并且根据该特征推荐合适的修复者。通过与传统机器学习方法(如贝叶斯方法和支持向量机方法)进行对比,该方法可以比较有效地在众多开发者中找出合适的缺陷修复者。     

一种融合D_BBAS方法的重复缺陷报告检测

重复缺陷报告的自动化检测可以减少开发冗余和维护成本,最近重复缺陷报告的检测倾向于利用深度神经网络,并考虑结构化和非结构化信息来生成混合表示特征。为了更有效获得缺陷报告的非结构化信息的特征,提出一种D_BBAS（Doc2vec and BERT BiLSTM-attention similarity）方法,它基于大规模缺陷报告库训练特征提取模型,生成能反映深层次语义信息的缺陷摘要文本表示集和缺陷描述文本表示集;利用这两个分布式的表示集计算出缺陷报告对的相似度,从而得到两个新的相似度特征;这两个新特征将与基于结构化信息生成的传统特征结合后参与重复缺陷报告的检测。在著名开源项目Eclipse、NetBeans 和Open Office的缺陷报告库上验证了D_BBAS方法的有效性,其中包含超过50万个缺陷报告。实验结果表明,相比于代表性方法,该方法的F1值平均提升了1.7%,证明了D_BBAS方法的有效性。     

融合文本分布式表示的重复缺陷报告检测

重复缺陷报告检测能够避免对描述同一缺陷的多份报告进行重复的任务分派和修复,可降低软件维护成本。为了进一步提高检测的准确率,提出一种融合文本分布式表示的重复缺陷报告检测方法。首先,基于大规模缺陷报告数据库训练Doc2Vec模型并抽取缺陷报告的分布式表示,将不同长度的缺陷报告编码为统一长度的稠密向量。接着,通过比较这些向量来计算不同缺陷报告的相似程度,将其作为一种新特征与重复缺陷报告检测过程常用的其它特征进行融合,并利用机器学习算法训练二元分类模型。在公开的Bugzilla重复缺陷报告数据集上的实验结果表明,相比于代表性方法D_TS,本文方法的F1值平均提升了2%,说明了新特征的有效性。     

Automated,highly-accurate,bug assignment using machine learning and tossing graphs

Empirical studies indicate that automating the bug assignment process has the potential to significantly reduce software evolution effort and costs. Prior work has used machine learning techniques to automate bug assignment but has employed a narrow band of tools which can be ineffective in large, long-lived software projects. To redress this situation, in this paper we employ a comprehensive set of machine learning tools and a probabilistic graph-based model (bug tossing graphs) that lead to highly-accurate predictions, and lay the foundation for the next generation of machine learning-based bug assignment. Our work is the first to examine the impact of multiple machine learning dimensions (classifiers, attributes, and training history) along with bug tossing graphs on prediction accuracy in bug assignment. We validate our approach on Mozilla and Eclipse, covering 856,259 bug reports and 21 cumulative years of development. We demonstrate that our techniques can achieve up to 86.09% prediction accuracy in bug assignment and significantly reduce tossing path lengths. We show that for our data sets the Naïve Bayes classifier coupled with product–component features, tossing graphs and incremental learning performs best. Next, we perform an ablative analysis by unilaterally varying classifiers, features, and learning model to show their relative importance of on bug assignment accuracy. Finally, we propose optimization techniques that achieve high prediction accuracy while reducing training and prediction time.     

Bug Triaging Based on Tossing Sequence Modeling

Bug triaging, which routes the bug reports to potential fixers, is an integral step in software development and maintenance. To make bug triaging more efficient, many researchers propose to adopt machine learning and information retrieval techniques to identify some suitable fixers for a given bug report. However, none of the existing proposals simultaneously take into account the following three aspects that matter for the efficiency of bug triaging:1) the textual content in the bug reports, 2) the metadata in the bug reports, and 3) the tossing sequence of the bug reports. To simultaneously make use of the above three aspects, we propose iTriage which first adopts a sequence-to-sequence model to jointly learn the features of textual content and tossing sequence, and then uses a classification model to integrate the features from textual content, metadata, and tossing sequence. Evaluation results on three different open-source projects show that the proposed approach has significantly improved the accuracy of bug triaging compared with the state-of-the-art approaches.     

面向用户的软件缺陷报告特征重要度分析

缺陷的及时反馈与修复是开源软件长久健康发展的基本保障, 面对每天提交的大量、包含多方面因素的开源软件缺陷报告, 很多缺陷报告因为描述遗漏或不准确, 而影响缺陷有效判定和缺陷修复进程; 而面对需要填报的复杂缺陷报告信息, 报告提交者也无法确定哪些属性是关键的、哪些需要重点描述致使提交缺陷报告质量不高. 综合文献对缺陷报告描述的5个维度28种特征进行分析, 按照维度间和维度内多特征两个角度对缺陷报告特征进行重要度排序对比, 结果显示按照维度分析: 文本特征和报告者经验特征两个维度的F1值和准确率指标最高, 而每个维度内特征也显示了不同重要度, 从而可以指导缺陷提交者规范缺陷报告提交, 也可以指导修复者进行缺陷判定和缺陷修复.     

KSAP: An approach to bug report assignment using KNN search and heterogeneous proximity

ContextBug report assignment, namely, to assign new bug reports to developers for timely and effective bug resolution, is crucial for software quality assurance. However, with the increasing size of software system, it is difficult to assign bugs to appropriate developers for bug managers.ObjectiveThis paper propose an approach, called KSAP (K-nearest-neighbor search and heterogeneous proximity), to improve automatic bug report assignment by using historical bug reports and heterogeneous network of bug repository.MethodWhen a new bug report was submitted to the bug repository, KSAP assigns developers for the bug report by using a two-phase procedure. The first phase is to search historically-resolved similar bug reports to the new bug report by K-nearest-neighbor (KNN) method. The second phase is to rank the developers who contributed to those similar bug reports by heterogeneous proximity.ResultsWe collected bug repositories of Mozilla, Eclipse, Apache Ant and Apache Tomcat6 projects to investigate the performance of the proposed KSAP approach. Experimental results demonstrate that KSAP can improve the recall of bug report assignment between 7.5–32.25% in comparison with the state of art techniques. When there is only a small number of developer collaborations on common bug reports, KSAP has shown its excellence over other sate of art techniques. When we tune the parameters of the number of historically-resolved similar bug reports (K) and the number of developers (Q) for recommendation, KSAP keeps its superiority steadily.ConclusionThis is the first paper to demonstrate how to automatically build heterogeneous network of a bug repository and extract meta-paths of developer collaborations from the heterogeneous network for bug report assignment.     

Automated bug assignment: Ensemble-based machine learning in large scale industrial contexts

Bug report assignment is an important part of software maintenance. In particular, incorrect assignments of bug reports to development teams can be very expensive in large software development projects. Several studies propose automating bug assignment techniques using machine learning in open source software contexts, but no study exists for large-scale proprietary projects in industry. The goal of this study is to evaluate automated bug assignment techniques that are based on machine learning classification. In particular, we study the state-of-the-art ensemble learner Stacked Generalization (SG) that combines several classifiers. We collect more than 50,000 bug reports from five development projects from two companies in different domains. We implement automated bug assignment and evaluate the performance in a set of controlled experiments. We show that SG scales to large scale industrial application and that it outperforms the use of individual classifiers for bug assignment, reaching prediction accuracies from 50 % to 89 % when large training sets are used. In addition, we show how old training data can decrease the prediction accuracy of bug assignment. We advice industry to use SG for bug assignment in proprietary contexts, using at least 2,000 bug reports for training. Finally, we highlight the importance of not solely relying on results from cross-validation when evaluating automated bug assignment.     

基于知识图谱的跨项目安全缺陷报告预测方法

安全缺陷报告可以描述软件产品中的安全关键漏洞.为了消除软件产品的安全攻击风险,安全缺陷报告(security bug report, SBR)预测越来越受到研究人员的关注.但在实际软件开发场景中,需要进行软件安全漏洞预测的项目可能是来自新公司或属于新启动的项目,没有足够的已标记安全缺陷报告供在实践中构建此软件安全漏洞预测模型.一种简单的解决方案就是使用迁移模型,即利用其他项目已经标记过的数据来构建预测模型.受到该领域最近的两项研究工作的启发,以安全关键字过滤为思路提出一种融合知识图谱的跨项目安全缺陷报告预测方法KG-SBRP (knowledge graph of security bug report prediction).使用安全缺陷报告中的文本信息域结合CWE(common weakness enumeration)与CVE Details (common vulnerabilities and exposures)共同构建三元组规则实体,以三元组规则实体构建安全漏洞知识图谱,在图谱中结合实体及其关系识别安全缺陷报告.将数据分为训练集和测试集进行模型拟合和性能评估.所构建的模型...