A cost-effective software testing strategy employing online feedback information

An online partitioning strategy is presented, in which test cases are selected based on feedback information collected during the testing process. The strategy differs from con- ventional approaches because the partitioning is performed online rather than off-line and because the partitioning is not based on program code or specifications. It can, therefore, be implemented in the absence of the source code or specification of the program under test. The cost-effectiveness of the proposed strategy has been empirically investigated with a set of subject programs, namely, SPACE, SED, GREP, and the Siemens Suite of Programs. The results demonstrate that the proposed strategy constantly achieves large savings in terms of the total number of test case executions needed to detect all faults

The design of control systems for automated transport

In this thesis, the design of control systems for automated transport is approached from a systems point of view. The first section discusses general aspects of control system design, namely, system structure, design for reliability and communication requirements. The treatment of the subject is novel and in particular, Chapter 2 - 'The Design of 'Fail-Soft' Systems', is completely original. The second section of the thesis discusses in detail, the longitudinal control of vehicles, emergency control and junction control. In all a novel viewpoint is adopted. There are two broad categories of transport control, synchronous and asynchronous. The former has been the subject of considerable research, the latter has been completely ignored. This thesis concentrates on asynchronous control. Contrary to the views stated by many researchers, it is shown that asynchronous control can achieve a very much better performance than synchronous controllers. In addition, a completely new form of asynchronous control has been devised, and is presented in this thesis. This scheme, the asynchronous marker-follower control, combines the advantages of synchronous controllers (simple processing and low communication requirements) with the advantages of asynchronous controllers (an efficient use of track and a good response to failures). In the last section of the thesis, the computer simulation models, used to examine the control schemes, are described. The interactions between automated vehicles are particularly complex, consequently clear presentation is important. To this end a number of graph plotting routines were written and a moving picture display technique developed. Each Chapter is supported by a bibliography of references particularly relevant to the chapter. In addition a comprehensive bibliography is contained in the Appendices

Data Extraction via Semantic Regular Expression Synthesis

Many data extraction tasks of practical relevance require not only syntactic pattern matching but also semantic reasoning about the content of the underlying text. While regular expressions are very well suited for tasks that require only syntactic pattern matching, they fall short for data extraction tasks that involve both a syntactic and semantic component. To address this issue, we introduce semantic regexes, a generalization of regular expressions that facilitates combined syntactic and semantic reasoning about textual data. We also propose a novel learning algorithm that can synthesize semantic regexes from a small number of positive and negative examples. Our proposed learning algorithm uses a combination of neural sketch generation and compositional type-directed synthesis for fast and effective generalization from a small number of examples. We have implemented these ideas in a new tool called Smore and evaluated it on representative data extraction tasks involving several textual datasets. Our evaluation shows that semantic regexes can better support complex data extraction tasks than standard regular expressions and that our learning algorithm significantly outperforms existing tools, including state-of-the-art neural networks and program synthesis tools

Doctor of Philosophy

dissertationAggressive random testing tools, or fuzzers, are impressively effective at finding bugs in compilers and programming language runtimes. For example, a single test-case generator has resulted in more than 460 bugs reported for a number of production-quality C compilers. However, fuzzers can be hard to use. The first problem is that failures triggered by random test cases can be difficult to debug because these tests are often large. To report a compiler bug, one must often construct a small test case that triggers the bug. The existing automated test-case reduction technique, delta debugging, is not sufficient to produce small, reportable test cases. A second problem is that fuzzers are indiscriminate: they repeatedly find bugs that may not be severe enough to fix right away. Third, fuzzers tend to generate a large number of test cases that only trigger a few bugs. Some bugs are triggered much more frequently than others, creating needle-in-the-haystack problems. Currently, users rule out undesirable test cases using ad hoc methods such as disallowing problematic features in tests and filtering test results. This dissertation investigates approaches to improving the utility of compiler fuzzers. Two components, an aggressive test-case reducer and a tamer, are added to the fuzzing workflow to make the fuzzer more user friendly. We introduce C-Reduce, an aggressive test-case reducer for C/C++ programs, which exploits rich domain-specific knowledge to output test cases nearly as good as those produced by skilled humans. This reducer produces outputs that are, on average, more than 30 times smaller than those produced by the existing reducer that is most commonly used by compiler engineers. Second, this dissertation formulates and addresses the fuzzer taming problem: given a potentially large number of random test cases that trigger failures, order them such that diverse, interesting test cases are highly ranked. Bug triage can be effectively automated, relying on techniques from machine learning to suppress duplicate bug-triggering test cases and test cases triggering known bugs. An evaluation shows the ability of this tool to solve the fuzzer taming problem for 3,799 test cases triggering 46 bugs in a C compiler

Enhancing mirror adaptive random testing through dynamic partitioning

Context: Adaptive random testing (ART), originally proposed as an enhancement of random testing, is often criticized for the high computation overhead of many ART algorithms. Mirror ART (MART) is a novel approach that can be generally applied to improve the efficiency of various ART algorithms based on the combination of ''divide-and-conquer'' and ''heuristic'' strategies. Objective: The computation overhead of the existing MART methods is actually on the same order of magnitude as that of the original ART algorithms. In this paper, we aim to further decrease the order of computation overhead for MART. Method: We conjecture that the mirroring scheme in MART should be dynamic instead of static to deliver a higher efficiency. We thus propose a new approach, namely dynamic mirror ART (DMART), which incrementally partitions the input domain and adopts new mirror functions. Results: Our simulations demonstrate that the new DMART approach delivers comparable failure-detection effectiveness as the original MART and ART algorithms while having much lower computation overhead. The experimental studies further show that the new approach also delivers a better and more reliable performance on programs with failure-unrelated parameters. Conclusion: In general, DMART is much more cost-effective than MART. Since its mirroring scheme is independent of concrete ART algorithms, DMART can be generally applied to improve the cost-effectiveness of various ART algorithms

Domestic violence exposure: Effects on adolescents\u27 dating relationships

The purposes of this study are to examine adolescents\u27 level of exposure to domestic violence throughout their life and to explore whether there is a difference in the likelihood of engaging in conflict behaviors, justification of violence and help-seeking behaviors between adolescents who have been exposed to domestic violence and those who have not

Avionics requirements for all weather landing of advanced SST's. Volume II - State of the art review of all weather landing system techniques Final report

State of art review of all-weather landing techniques and instrumentation for advanced SS