Changsup Keum

Generating test cases for web services using extended finite state machine

Web services utilize a standard communication infrastructure such as XML and SOAP to communicate through the Internet. Even though Web services are becoming more and more widespread as an emerging technology, it is hard to test Web services because they are distributed applications with numerous aspects of runtime behavior that are different from typical applications. This paper presents a new approach to testing Web services based on EFSM (Extended Finite State Machine). WSDL (Web Services Description Language) file alone does not provide dynamic behavior information. This problem can be overcome by augmenting it with a behavior specification of the service. Rather than domain partitioning or perturbation techniques, we choose EFSM because Web services have control flow as well as data flow like communication protocols. By appending this formal model of EFSM to standard WSDL, we can generate a set of test cases which has a better test coverage than other methods. Moreover, a procedure for deriving an EFSM model from WSDL specification is provided to help a service provider augment the EFSM model describing dynamic behaviors of the Web service. To show the efficacy of our approach, we applied our approach to Parlay-X Web services. In this way, we can test Web services with greater confidence in potential fault detection.

Transformation Rules for Synthesis of UML Activity Diagram from Scenario-Based Specification

Although synthesis was considered an important and challenging approach to construction of a program or a program model in software development, most of research on synthesis has been devoted to the construction of state machine models or variations of them. Recently, as process modeling through languages like UML Activity Diagram and BPMN appears as a new paradigm of software development, the ability to synthesize models in such languages from requirements would tremendously increase the scope of automatic software development. This paper presents transformation rules for synthesis of UML Activity Diagrams from scenario-based specifications modeled as UML Sequence Diagrams. To that end, we first identify various control flow patterns of Sequence Diagrams and define rules for mapping them to corresponding parts of Activity Diagram. In order to make precise such mapping labeling rules are introduced for the patterns. Also we provide a synthesis algorithm for construction of a UML Activity Diagram from scenarios.

CoR-MAC: Contention over Reservation MAC Protocol for Time-Critical Services in Wireless Body Area Sensor Networks

Reserving time slots for urgent data, such as life-critical information, seems to be very attractive to guarantee their deadline requirements in wireless body area sensor networks (WBASNs). On the other hand, this reservation imposes a negative impact on performance for the utilization of a channel. This paper proposes a new channel access scheme referred to as the contention over reservation MAC (CoR-MAC) protocol for time-critical services in wireless body area sensor networks. CoR-MAC uses the dual reservation; if the reserved time slots are known to be vacant, other nodes can access the time slots by contention-based reservation to maximize the utilization of a channel and decrease the delay of the data. To measure the effectiveness of the proposed scheme against IEEE 802.15.4 and IEEE 802.15.6, we evaluated their performances with various performance indexes. The CoR-MAC showed 50% to 850% performance improvement in terms of the delay of urgent and time-critical data according to the number of nodes.

Adaptive Resource Balancing for Serviceability Maximization in Fog Radio Access Networks

Serviceability is the ability of a network to serve user equipments (UEs) within desired requirements (e.g., throughput, delay, and packet loss). High serviceability is considered as one of the key foundational criteria toward a successful fog radio access infrastructure satisfying the Internet of Things paradigm in the 5G era. In this paper, we propose an adaptive resource balancing (ARB) scheme for serviceability maximization in fog radio access networks wherein the resource block (RB) utilization among remote radio heads (RRHs) are balanced using the backpressure algorithm with respect to a time-varying network topology issued by potential RRH mobilities. The optimal UE selection for service migration from a high-RB-utilization RRH to its neighboring low-RB-utilization RRHs is determined by the Hungarian method to minimize RB occupation after moving the service. Analytical results reveal that the proposed ARB scheme provides substantial gains compared with the standalone capacity-aware, max-rate, and cache-aware UE association approaches in terms of serviceability, availability, and throughput.

Architecture-based testing of service-oriented applications in distributed systems

Abstract Context Testing distributed service-oriented applications (SOAs) is more challenging than testing monolithic applications since these applications have complex interactions between participant services. Test engineers can observe test results only through a front service that handles request messages sent by test engineers. Message exchanges between participant services are hidden behind the front service and cannot be easily observed or controlled through the front service. For this reason, testing SOAs suffer from limited observability and controllability problem. Objective This paper proposes a new test method that is architecture-based and exploits interaction architecture of a SOA. The proposed test method alleviates the limited observability and controllability problem by employing test architecture, thereby facilitating test execution and analysis through monitoring and controlling message exchanges. Method Our proposed method derives an interaction architecture from the specification of a SOA. Test architectures can be designed from the derived interaction architecture by extending it with additional test elements. At the same time, architecture-neutral test scenarios are automatically generated from the test model that is constructed from the specification. Our method combines test architecture information with the test scenarios to obtain architecture-enabled test scenarios under the selected test architectures. Finally, architecture-enabled test execution and analysis are conducted in the real network environment. Results The efficacy of the proposed method is demonstrated with an industrial case study, which shows that it is practical and effective for testing SOAs. Even though our method increases an additional test generation effort owing to test architecture, it is counterbalanced by higher fault detection rate and faster fault locating time. Conclusion The main benefit of our approach is that using test architecture it enhances testability of SOA by increasing observability and controllability through monitoring and controlling message exchanges. Our architecture-based test method enables test engineers to detect faults efficiently and also reduce fault locating time significantly.

Design of communication protocols using a message transfer pattern

Design patterns help to improve software quality and reduce development cost by reusing experience of experts for recurring problems. Patterns have potential to be useful in almost all areas of software systems, but to date they are mainly concentrated on the development of object-oriented systems. In this paper, we apply the pattern concept to the description of communication protocols, particularly focusing on message interaction. We hypothesize that many communication protocols can be developed using a few recurring patterns to obtain an initial design description of a system. For the protocol description, we propose a set of patterns which are grouped in two categories: structural and behavioural patterns. A complex protocol can be obtained by composing such patterns. To show the usefulness of our patterns in a realistic application, we perform a case study for an ATM signalling protocol design. Copyright

Method of application driven QoS service in open service platform based on RESTful web services

In this paper, the detailed functional architecture for QoS RESTful web services (i.e. application driven QoS) in open service platform was designed that enables IT developers to create applications using telecommunications network elements. In the modeling of QoS RESTful web services, we proposed resource definitions and the HTTP verbs applicable for each of these resources. And we described sequence diagram for the above model. Also, we measured the TPS (Transaction Per Second) of the open service platform including QoS RESTful web services above.

NGOSS based OSS/BSS architecture for hosting common platform for convergence services

Recently, various types of converged services are appeared because of the rapid development of the information & communication technology and the platform technology. These converged services are developed using convergence service development platforms. Recently, the notion of the common platform for development of various convergence services is appeared in order to provide universally platform service for service providers in various fields of industry. In this paper, we explore considerations for operating and managing the common platform for converged services, and propose a NGOSS based OSS/BSS architecture for hosting a common platform for converged services. Proposed architecture brings efficiency operation and management of the common platform. The existing OSSs of most service providers have deficiencies in supporting common platform for converged services. The proposed architecture settles the problems using knowledge-base of NGOSS and OSS/J.

Poster: Architecture Reconstruction and Evaluation of Blockchain Open Source Platform

Recently, public interest in the blockchain technology has surged and various applications based on the technology have emerged. However, there has been little study on architectural evaluations of popular block chain platforms that can help the developers choose an appropriate architecture matching their needs. In this paper, we reconstruct and evaluate the architecture of Hyperledger and Ethereum, which are representative open source platforms for blockchain. The evaluation results indicate that Hyperledger is strong in modifiability and performance whereas Ethereum is better in security.

Architecture-Based Software Testing

It has been recognized by many researchers that the notion of test architecture should be utilized for software testing to cope with the task of testing complicated software, as it can support test architecture design and test case generation based on test architecture as well as efficient fault detection and error locating. However, in the current software testing theory and practice, the notion of test architecture and how it can be utilized for software testing are not well understood. To redress this situation, this paper provides foundational concepts and principles of architecture-based software testing to help utilize test architecture for software testing. Case study experiments are conducted to show how the concepts and principles of architecture-based software testing work and the effects that can be obtained by using architecture-based software testing.