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Improving the Efficacy of Automated Test Generation
Get PDFExploring the execution space is essential to many program analysis tasks such as finding vulnerabilities in the program under test. Starting from a corpus of initial inputs (a.k.a. seeds), automated test generation aims to find more and more inputs (or testcases) that exercise new program states, and hopefully, some inputs will reach interesting states, e.g., triggering a vulnerability. Based on the observation that under-tested code is more likely to have bugs, coverage-guided testing, which tries to maximize the code coverage, works very well in practice.Notably, coverage-guided testing usually involves three stages: seed selection, seed schedule, and new input generation.This dissertation addresses three core problems in each stage and advances the state-of-the-art on automated test generation.First, we conduct the first systematic study on the impact of coverage metrics. In particular, we formally define and discuss the concept of sensitivity to compare different coverage metrics. We show that certain program states (e.g., vulnerabilities) cannot be reached without enough sensitivity. We then selectively present several metrics with different sensitivities, and evaluate them on a large set of programs. Results show that each metric has its unique merit in terms of vulnerability finding. However, there is no grand slam one that defeats all the others when the computational resources are limited. Specifically, a high sensitive coverage metric can select too many seeds that overwhelm the current scheduling algorithms and lead to poor performance.Second, we aim to address the seed explosion problem caused by a sensitive coverage metric. To this end, we model this problem as a trade-off between exploration and exploitation. Then, we design a novel multi-level coverage metric that incorporates sensitive coverage metrics in a novel way. Combined with a reinforcement-learning-based hierarchical seed scheduler, our approach not only can trigger more bugs and achieve higher code coverage, but also can achieve the same coverage faster than existing approaches. However, we also discover that with a large amount of seeds, the input generation stage will become a bottleneck. That is, the likelihood of a (randomly generated) input being selected as a new seed decreases when the input size and the corpus size increase.One way to improve the efficiency of input generation is to replace random mutation with path constraints solving, e.g., by leveraging concolic execution (CE). Ideally, each input generated by a concolic execution engine should visit a new state and be selected as a new seed. However, our study finds that a considerable amount (as high as 50\%) inputs actually failed to reach new states thus are not selected, especially when handling format inputs. To address this problem, in the last piece of this dissertation, we propose format-aware solving that leverages path constraints to infer input format information, and leverages inferred format information to guide the constructing and solving of path constraints. Evaluation shows that our approach can negate significantly more branches, lead to deeper new paths, and cover more code
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Towards Improving Cybersecurity and Augmenting Human Training Performance Using Brain Imaging Techniques
Get PDFHuman behaviors can weaken the security of cyber-physical systems. However, conventional security research focuses more on hardware and software security than analyzing and improving human behaviors to provide better protection for digital systems. In this regard, we study the neural insights of computer systems users to identify cyber-attacks, such as phishing, and improve cybersecurity. First, we analyze neural activities to detect phishing attacks. We demonstrate that the variations in neural activity levels can be utilized to identify phishing websites with improved data preprocessing and feature extraction methods. Second, we study users' neural activities to learn their high-level intents when they use applications. The inferred intents are then used to ensure the security and privacy of sensitive resources, such as cameras and multi-media files. Finally, we design an adaptive training model that enables users to differentiate between benign and malicious scenarios. We consider both behavior and neural metrics to develop adaptive logic. Our experimental results show that participants trained with our approach outperform in the transfer task than those trained with non-adaptive and behaviorally adaptive designs
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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Building an Efficient Concolic Executor
Get PDFConcolic execution is a powerful program analysis technique for systematically exploring execution paths. Compared to random-mutation-based fuzzing, concolic execution is especially good at exploring code paths guarded by complex and tight branch predicates. However, the existing concolic executors face severe scalability issues when processing real-world programs - they impose a significant performance overhead and consume a large amount of extra memory. Those issues prevent concolic execution from being adopted widely in practice. Motivated by this, we propose a study to characterize and mitigate the bottlenecks in the concolic execution systematically. Concretely, we propose 1). a time and space-efficient constraints collector based on a high-optimized dynamic data-flow analysis framework 2). an efficient and scalable path-constraints fuzzer that can find feasible inputs at a high speed. The preliminary evaluation results show that these two techniques can enable much faster concolic execution with a much smaller memory footprint
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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