Wuwei Shen

Bio: Wuwei Shen is an academic researcher from Western Michigan University. The author has contributed to research in topics: Unified Modeling Language & Software development. The author has an hindex of 11, co-authored 47 publications receiving 558 citations. Previous affiliations of Wuwei Shen include University of Michigan.

On the Use of Stack Traces to Improve Text Retrieval-Based Bug Localization

Abstract: Many bug localization techniques rely on Text Retrieval (TR) models. The most successful approaches have been proven to be the ones combining TR techniques with static analysis, dynamic analysis, and/or software repositories information. Dynamic software analysis and software repositories mining bring a significant overhead, as they require instrumenting and executing the software, and analyzing large amounts of data, respectively. We propose a new static technique, named Lobster (Locating Bugs using Stack Traces and text Retrieval), which is meant to improve TR-based bug localization without the overhead associated with dynamic analysis and repository mining. Specifically, we use the stack traces submitted in a bug report to compute the similarity between their code elements and the source code of a software system. We combine the stack trace based similarity and the textual similarity provided by TR techniques to retrieve code elements relevant to bug reports. We empirically evaluated Lobster using 155 bug reports containing stack traces from 14 open source software systems. We used Lucene, an optimized version of VSM, as baseline of comparison. The results show that, in average, Lobster improves or maintains the effectiveness of Lucene-based bug localization in 82% of the cases.

Fuzzing: State of the Art

Abstract: As one of the most popular software testing techniques, fuzzing can find a variety of weaknesses in a program, such as software bugs and vulnerabilities, by generating numerous test inputs. Due to its effectiveness, fuzzing is regarded as a valuable bug hunting method. In this paper, we present an overview of fuzzing that concentrates on its general process, as well as classifications, followed by detailed discussion of the key obstacles and some state-of-the-art technologies which aim to overcome or mitigate these obstacles. We further investigate and classify several widely used fuzzing tools. Our primary goal is to equip the stakeholder with a better understanding of fuzzing and the potential solutions for improving fuzzing methods in the spectrum of software testing and security. To inspire future research, we also predict some future directions with regard to fuzzing.

An Automatic Testing Approach for Compiler Based on Metamorphic Testing Technique

Abstract: Compilers play an important role in software development, and it is quite necessary to perform abundant testing to ensure the correctness of compilers. A critical task in compiler testing is to validate the semantic-soundness property which requires consistence between semantics of source programs and behavior of target executables. For validating this property, one main challenging issue is generation of a test oracle. Most existing approaches fall into two main categories when dealing with this issue: reference-based approaches and assertion-based approaches. All these approaches have their weakness when new programming languages are involved or test automation is required. To overcome the weakness in the existing approaches, we propose a new automatic approach for testing compiler. Our approach is based on the technique of metamorphic testing, which validates software systems via so-called "metamorphic relations". We select the equivalence-preservation relation as the metamorphic relation and propose an automatic metamorphic testing framework for compiler. We also propose three different techniques for automatically generating equivalent source programs as test inputs. Based on our approach, we developed a tool called Mettoc. Our mutation experiments show that Mettoc is effective to reveal compilers' errors in terms of the semantic-soundness property. Moreover, the empirical results also reveal that simple approaches for constructing test inputs are not weaker than complicated ones in terms of fault-detection capability. We also applied Mettoc in testing a number of open source compilers, and two real errors in GCC-4.4.3 and UCC-1.6 respectively have been detected by Mettoc.

A toolset for supporting UML static and dynamic model checking

Abstract: The Unified Modeling Language has become widely accepted as a standard in software development. Several tools have been produced to support UML model validation. However most of them support either static or dynamic model checking; and no tools support to check both static and dynamic aspects of a UML model. But a UML model should include the static and dynamic aspects of a software system. Furthermore, these UML tools translate a UML model into a validation language such as PROMELA. But they have some shortcomings: there is no proof of correctness (with respect to the UML semantics) for these tools. In order to overcome these shortcomings, we present a toolset which can validate both static and dynamic aspects of a model; and this toolset is based on the semantic model using Abstract State Machines. Since the toolset is derived from the semantic model, the toolset is correct with respect to the semantic model.

Evaluating pattern conformance of UML models: a divide-and-conquer approach and case studies

Abstract: A design pattern is realized in various forms depending on the context of the applications. There has been intensive research on detecting pattern instances in models and in implementations. However, little work addresses variations of pattern realization. This paper describes an approach for evaluating conformance of pattern variations. This approach uses a divide-and-conquer strategy to evaluate the structural conformance of a UML class diagram to the solution of a design pattern. A design pattern is specified in an extension of the UML that defines the pattern in terms of roles. To demonstrate the approach, we use the Visitor pattern and two case studies of a price calculator and a word processor. We also present a prototype tool that supports the approach.

Metamorphic Testing: A Review of Challenges and Opportunities

Abstract: Metamorphic testing is an approach to both test case generation and test result verification. A central element is a set of metamorphic relations, which are necessary properties of the target function or algorithm in relation to multiple inputs and their expected outputs. Since its first publication, we have witnessed a rapidly increasing body of work examining metamorphic testing from various perspectives, including metamorphic relation identification, test case generation, integration with other software engineering techniques, and the validation and evaluation of software systems. In this article, we review the current research of metamorphic testing and discuss the challenges yet to be addressed. We also present visions for further improvement of metamorphic testing and highlight opportunities for new research.

A Survey on Metamorphic Testing

Abstract: A test oracle determines whether a test execution reveals a fault, often by comparing the observed program output to the expected output. This is not always practical, for example when a program's input-output relation is complex and difficult to capture formally. Metamorphic testing provides an alternative, where correctness is not determined by checking an individual concrete output, but by applying a transformation to a test input and observing how the program output “morphs” into a different one as a result. Since the introduction of such metamorphic relations in 1998, many contributions on metamorphic testing have been made, and the technique has seen successful applications in a variety of domains, ranging from web services to computer graphics. This article provides a comprehensive survey on metamorphic testing: It summarises the research results and application areas, and analyses common practice in empirical studies of metamorphic testing as well as the main open challenges.

Launcher with helical antenna and methods for use therewith

Abstract: Aspects of the subject disclosure may include, for example, a launching device including a transmitter configured to generate a radio frequency signal in a microwave frequency band. A helical antenna is configured to launch the radio frequency signal as a guided electromagnetic wave that is bound to an outer surface of a transmission medium, wherein the guided electromagnetic wave propagates along the outer surface of the transmission medium without an electrical return path. Other embodiments are disclosed.