Changsun Shin

A TMO-Based Object Group Model to Structuring Replicated Real-Time Objects for Distributed Real-Time Applications

We designed the TMO-based Object Group (TMOOG) model with various services for supporting distributed real-time applications, and analyzed whether these given service strategies can be adopted and worked to this model well. In this paper, we are interested in the object group model that can be defined as a single logical view system for providing replication transparency and supporting real-time services. The TMOOG model is based on the concept of the object group recommended by the TINA-C and the OMG. Our model consists of a set of computational Time-triggered and Message-triggered Objects(TMOs) for real-time services and several management objects providing how to manage these TMOs and maintain their information such as repositories for executing given distributed real-time applications. The TMOs in an object group may act as copies, called replicas, of a replicated object with the same roles. For the distributed real-time applications, we focused on the following strategies; dynamic object selection and binding strategy to support replication transparency, and real-time strategy to support real-time applications. For supporting these strategies, we adopted the Dynamic Binder object, the Scheduler object and some related objects to our model. These strategies can be flexibly implemented as object implementations by using appropriate algorithms in the model. Our model is designed on Commercial Off-The-Shelf (COTS) middleware without restricting the special Object Request Broker (ORB) or the operating system. Finally, from the analyzed results numerically, we verified whether our model can support these strategies and showed the feasibility of these service strategies adopted from TMOOG model.

Distributed Object Group Framework with Dynamic Reconfigurability of Distributed Services

In this paper, we constructed the Distributed Object Group Framework(DOGF) which is a reconfigurable architecture supporting dynamically adaptation of distributed services. We also developed the distributed application simulator to verify the adaptability and reconfigurability of our framework. The DOGF provides appropriate grouping of distributed objects for executing given distributed applications as the point of view of a single logical view system, and supports the adaptive distributed services for dynamic reconfiguration of distributed application. In constructing procedure of the DOGF, we designed the distributed services that consist of the objects supporting service, the load balancing service, and the real-time service. We also implemented the managing technique for dynamic reconfiguring the distributed services. Finally, for verifying whether the DOGF can support the dynamic reconfigurability of distributed services or not, we developed the Defence System against Invading Enemy Planes(DSIEP) simulator as a practical use of distributed application with real-time property on the DOGF. From this, with adaptation of given load balancing policies, we analyzed the average execution times and the deadline violation rates as the execution results for the client’s request.