In-Young Ko

Test Cases Generation from UML Activity Diagrams

UML activity diagram is a notation suitable for modeling a concurrent system in which multiple objects interact with each other. This paper proposes a method to generate test cases from UML activity diagrams that minimizes the number of test cases generated while deriving all practically useful test cases. Our method first builds an I/O explicit activity diagram from an ordinary UML activity diagram and then transforms it to a directed graph, from which test cases for the initial activity diagram are derived. This conversion is performed based on the single stimulus principle, which helps avoid the state explosion problem in test generation for a concurrent system.

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.

SHAGE: a framework for self-managed robot software

Behavioral, situational and environmental changes in complex software, such as robot software, cannot be completely captured in software design. To handle this dynamism, self-managed software enables its services dynamically adapted to various situations by reconfiguring its software architecture during run-time. We have developed a practical framework, called SHAGE (Self-Healing, Adaptive, and Growing SoftwarE), to support self-managed software for intelligent service robots. The SHAGE framework is composed of six main elements: a situation monitor to identify internal and external conditions of a software system, ontology-based models to describe architecture and components, brokers to find appropriate architectural reconfiguration patterns and components for a situation, a reconfigurator to actually change the architecture based on the selected reconfiguration pattern and components, a decision maker/learner to find the optimal solution of reconfiguring software architecture for a situation, and repositories to effectively manage and share architectural reconfiguration patterns, components, and problem solving strategies. We conducted an experiment of applying the framework to an infotainment robot. The result of the experiment shows the practicality and usefulness of the framework for the intelligent service robots.

Composing Web services for large-scale tasks

By making it easy to explore combinations of multiple Web services, Eurasia helps users tackle large-scale information-management tasks and adapt and reuse the steps involved.

Spontaneous task composition in urban computing environments based on social, spatial, and temporal aspects

Ubiquitous and urban computing share the goal of enabling users to access networked services and resources anytime, anywhere. The intermesh of planned and situational activities is a distinguishable characteristic of urban computing environments. This produces a diversity of service requirements that need to be tackled by opportunistically suggesting appropriate services to users or social groups, without having a previous definition of applications in templates or any other descriptions in advance. This paper leverages the approach of task-oriented computing to represent user goals in tasks. A task is composed of unit-tasks: user centric configurations of abstract service coordinations. The focus of this paper is on the provision of a mechanism to cover the spontaneous unit-task composition cycle, based on social, spatial, and temporal aspects. This is realized by identifying the essential semantic elements that describe unit-tasks, UrbComp environments, and social groups. We have extended a unit-task selection mechanism from our previous work. In addition, this paper contributes a set of composability metrics based on social, spatial, and temporal aspects. These metrics concern the measurement of semantic interoperability and potential conflicts between unit-tasks or unit-task composites. These metrics are used to join unit-tasks together in sequences. Experimental results for a real dataset of tasks were obtained. These results show a suitable time-overhead for the unit-task selection mechanism. In addition, a simulation of arrivals at a crowded space was utilized to measure the performance, throughput, and efficacy ratio of the composition mechanism.

Dynamic coordination of information management services for processing dynamic web content

Dynamic Web content provides us with time-sensitive and continuously changing data. To glean up-to-date information, users need to regularly browse, collect and analyze this Web content. Without proper tool support this information management task is tedious, time-consuming and error prone, especially when the quantity of the dynamic Web content is large, when many information management services are needed to analyze it, and when underlying services/network are not completely reliable. This paper describes a multi-level, lifecycle (design-time and run-time) coordination mechanism that enables rapid, efficient development and execution of information management applications that are especially useful for processing dynamic Web content. Such a coordination mechanism brings dynamism to coordinating independent, distributed information management services. Dynamic parallelism spawns/merges multiple execution service branches based on available data, and dynamic run-time reconfiguration coordinates service execution to overcome faulty services and bottlenecks. These features enable information management applications to be more efficient in handling content and format changes in Web resources, and enable the applications to be evolved and adapted to process dynamic Web content.

SoIoT: Toward A User-Centric IoT-Based Service Framework

An emerging issue in urban computing environments is the seamless selection, composition, and delivery of user-centric services that run over what is known as the Internet of Things (IoT). This challenge is about enabling services actuated by IoT devices to be delivered spontaneously from the perspective of users. To accomplish this goal, we propose the Service-Oriented Internet of Things (SoIoT), a user-centric IoT-based service framework, which integrates services that utilize IoT resources in an urban computing environment. This framework provides a task-oriented computing approach that enables the composition of IoT-based services in a spontaneous manner to accomplish a user task. Tasks can also be recommended to users based on the available IoT resources in an environment and on the contextual knowledge that is represented and managed in social, spatial, and temporal aspects. These tasks are then bound to a set of service instances and performed in a distributed manner. This final composition ensures the Quality of Service (QoS) requirements of the tasks and is assigned to multiple client devices for the efficient utilization of IoT resources. We prove the practicality of our approach by showing a real-case service scenario implemented in our IoT-based test-bed as well as experimental results.

Dodona: automated oracle data set selection

Software complexity has increased the need for automated software testing. Most research on automating testing, however, has focused on creating test input data. While careful selection of input data is necessary to reach faulty states in a system under test, test oracles are needed to actually detect failures. In this work, we describe Dodona, a system that supports the generation of test oracles. Dodona ranks program variables based on the interactions and dependencies observed between them during program execution. Using this ranking, Dodona proposes a set of variables to be monitored, that can be used by engineers to construct assertion-based oracles. Our empirical study of Dodona reveals that it is more effective and efficient than the current state-of-the-art approach for generating oracle data sets, and can often yield oracles that are almost as effective as oracles hand-crafted by engineers without support.

Effective route maintenance and restoration schemes in mobile ad hoc networks.

This study proposes a location-based hybrid routing protocol to improve data packet delivery and to reduce control message overhead in mobile ad hoc networks. In mobile environments, where nodes move continuously at a high speed, it is generally difficult to maintain and restore route paths. Therefore, this study suggests a new flooding mechanism to control route paths. The essence of the proposed scheme is its effective tracking of the destination’s location based on the beacon messages of the main route nodes. Through experiments based on an NS-2 simulator, the proposed scheme shows improvements in the data packet delivery ratio and reduces the amount of routing control message overhead compared with existing routing protocols such as AODV, LAR, ZRP and AODV-DFR.

An Evolving Mobile E-Health Service Platform

With the wide spread use of cellular phones and the increased interests in the well-being of people, many vendors of cellular phones start to embed a variety of e-health services in their cellular phones. In this paper, we propose an e-health platform on which e-health services can be systematically developed by utilizing various functions and features, and by following guidelines provided by the platform.