Yinong Chen

WSDL-based automatic test case generation for Web services testing

Web services promote the specification based cooperation and collaboration among distributed applications in an open environment. To ensure the quality of the services that are published, bound, invoked and integrated at runtime, test cases have to be automatically generated and testing executed, monitored and analyzed at runtime. This paper presents the research to generate Web services test cases automatically based on the Web services specification language WSDL (Web Services Description Language), which carries the basic information of a service including its interface operations and the data transmitted. The WSDL file is first parsed and transformed into the structured DOM tree. Then, test cases are generated from two perspectives: test data generation and test operation generation. Test data are generated by analyzing the message data types according to standard XML schema syntax. Operation flows are generated based on the operation dependency analysis. Three types of dependencies are defined: input dependency, output dependency, and input/output dependency. Finally, the generated test cases are documented in XML based test files called service test specification.

Robot as a Service in Cloud Computing

Service-oriented architecture and cloud computing are becoming a dominant computing paradigm, as all major computing companies are supporting this paradigm and more and more organizations are adopting this paradigm. Robotics and service-oriented robotics computing start to joint this new paradigm in the past five years and are now ready to participate in large scale. This paper reports our research on service-oriented robotics computing and our design, implementation, and evaluation of Robot as a Service (RaaS) unit. To fully qualify the RaaS as a cloud computing unit, we have kept our design to comply with the common service standards, development platforms, and execution infrastructure. We also keep the source code open and allow the community to configure the RaaS following the Web 2.0 principles of participation. Developers can add, remove, and modify the RaaS of their own. For this purpose, we have implemented our RaaS on Windows and Linux operating systems running on Atom and Core 2 Duo architectures. RaaS supports programming languages commonly used for service-oriented computing such as Java and C#. Special efforts have been made to support Microsoft Visual Programming Language (VPL) for graphic composition. We are working with high schools to use RaaS and VPL in robotics camps and robotics competitions.

On Testing and Evaluating Service-Oriented Software

As service-oriented architecture matures and more Web services become available, developers must test an ever-increasing volume of services. A framework that defines and evaluates test-case potency based on coverage relationships can reduce testing effort while maintaining testings effectiveness.

Virtualization-based autonomic resource management for multi-tier Web applications in shared data center

As large data centers emerge, which host multiple Web applications, it is critical to isolate different application environments for security reasons and to provision shared resources effectively and efficiently to meet different service quality targets at minimum operational cost. To address this problem, we developed a novel architecture of resource management framework for multi-tier applications based on virtualization mechanisms. Key techniques presented in this paper include (1) establishment of the analytic performance model which employs probabilistic analysis and overload management to deal with non-equilibrium states; (2) a general formulation of the resource management problem which can be solved by incorporating both deterministic and stochastic optimizing algorithms; (3) deployment of virtual servers to partition resource at a much finer level; and (4) investigation of the impact of the failure rate to examine the effect of application isolation. Simulation experiments comparing three resource allocation schemes demonstrate the advantage of our dynamic approach in providing differentiated service qualities, preserving QoS levels in failure scenarios and also improving the overall performance while reducing the resource usage cost.

Cooperative and group testing in verification of dynamic composite Web services

Verifying Web services (WS) in a dynamic Service Oriented Architecture (SOA) is challenging because new services can be composed at runtime using existing WS. Furthermore, in a composite service, any component can be dynamically replaced during execution if the component fails. Another challenge is that the testing is time critical because verification must be conducted at runtime and in real time. We compare and contrast traditional software testing and WS testing techniques and propose a WS group testing technique to test composite services. The group testing technique also has the ability to evaluate the test scripts, automatically establish the oracle of the each test script, and identify faulty WS in a failed composite WS.

Collaborative Learning Using Wiki Web Sites for Computer Science Undergraduate Education: A Case Study

This paper proposes a collaborative approach to enhancing the student learning experience based on Web 2.0 principles. Specifically, wiki Web sites are used by students for collaboration and for publication of course assignments, which are then shared with the class. Web 2.0 principles include: the Web as platform, harnessing collective intelligence, data are the next Intel Inside, and rich user experiences. Based on a case study in a junior-level undergraduate class, this paper studies a set of six factors with comprehensive grading and evaluation criteria that are critical to make this approach successful. The six factors are knowledge base, motivation, research, social aspects, presentation, and feedback and support. The data collected show that most of the students who participated feel that this approach is exciting and rewarding, and that even some undergraduate students are able to produce original and innovative concepts. The data also show other interesting phenomena with respect to motivation, undergraduate research, and social aspects. Finally, the paper proposes a methodology of conducting a wiki project in a university class using a cyclic constant improvement process.

Adaptive testing, oracle generation, and test case ranking for Web services

Web services and service-oriented architecture are emerging technologies that are changing the way we develop and use computer software. Due to the standardization of Web services related description languages and protocols, as well as the open platforms, for the same Web service specification, many different implementations can be offered from different service providers. This paper presents an adaptive group testing technique that can test large number Web services simultaneously and effectively. Based on a case study, experiments are performed to validate the correctness and effectiveness of the technique.

Ontology-Based Test Modeling and Partition Testing of Web Services

Testing is useful to establish trust between service providers and clients. To test the service-oriented applications, automated and specification-based test generation and test collaboration are necessary. The paper proposes an ontology-based approach for Web services (WS) testing. A test ontology model (TOM) is defined to specify the test concepts, relationships, and semantics from two aspects: test design (such as test data, test behavior, and test cases) and test execution (such as test plan, schedule and configuration). The TOM specification using OWL (Web ontology language) can serve as test contracts among test components. Based on the WS semantic specification in OWL-S, the paper discusses the techniques to generate the sub-domains for input partition testing. Data pools are established for each parameter of the specified service. Data partitions are derived by class property and relationship analysis. Completeness and consistency (C&C) checking can be performed on the data partitions and data values, both within the TOM and against the OWL-S, by ontology class computation and reasoning. A prototype tool is implemented to support OWL-S analysis, test ontology generation and C&C checking.

Developing and assuring trustworthy Web services

Web services are emerging technologies that are changing the way we develop and use computer systems and software. Current Web services testing techniques are unable to assure the desired level of trustworthiness, which presents a barrier to WS applications in mission and business critical environments. This paper presents a framework that assures the trustworthiness of Web services. New assurance techniques are developed within the framework, including specification verification via completeness and consistency checking, specification refinement, distributed Web services development, test case generation, and automated Web services testing. Traditional test case generation methods only generate positive test cases that verify the functionality of software. The Swiss cheese test case generation method proposed in this paper is designed to perform both positive and negative testing that also reveal the vulnerability of Web services. This integrated development process is implemented in a case study. The experimental evaluation demonstrates the effectiveness of this approach. It also reveals that the Swiss cheese negative testing detects even more faults than positive testing and thus significantly reduces the vulnerability of Web services.

RTSOA: Real-Time Service-Oriented Architecture

This paper extends the traditional service-oriented architecture (SOA) to a new real-time SOA (RTSOA) and proposes a framework for the new architecture, by providing real-time service modeling, design, code generation, simulation, deployment, execution, orchestration, and management. The concepts, architecture, and enabling technique are studied for real-time SOA. In addition, an efficient algorithm is derived in the paper to find the optimal composition of real-time services subject to the real-time constraint