No abstract

Ubiquitous service environment based on DSN (distributed sensor networks) is poor in reliability of connection and has a high probability that the intrusion and the system failure may occur. In this paper, we propose an intrusion-tolerant Jini service architecture for integrating security and survivability support in order to provide end users with Jini services having a persistent state in ubiquitous environments. The proposed architecture is able to protect Jini service delivery not only from faults such as network partitioning or server crash but also from attacks exploiting flaws. It is designed to provide performance enough to show a low response latency so as to support seamless service usage. Through the experiment on a testbed, we have confirmed that the architecture is able to provide high security and availability at the level that the degradation of services quality is ignorable.

Jini security framework that is being maintained in Apache River project requires roughly 3 sequential tasks in every connection to cope with security threats in communication between clients and servers in the IoT sensor application. These tasks are sequentially proxy preparation, certification of identity and its credential for mutual authentication, and cryptographic operation for session encryption. Since the proxy preparation task is time spent on preparing a secure and trustable stub for both client/server sides, it is not one of the substantial communication-delay factors. We propose a method of improving proxy preparation reducing service connection delay by completing the preparation of mutual authentication data and session key while on proxy preparation task. Through experiments on a test-bed, we have confirmed that service connection delay time can be reduced by about 2.6 times in proportion to the message sizes through our proposed method. Our work presents an approach to reduce the additional overhead that would be paid for by applying the Jini security framework to the development of sensor application based on Jini IoT.

This paper presents an approach to the implementation of networked multimedia services using a real-time object model. The RT0.k model formalized earlier by Kim and Kopetz as a timeliness-guaranteed computing model has built up the foundation of our design methodology. We identified a generic structure of Multimedia Service Object System (MSOS) as a multimedia service programming paradigm. Each Scenario-RTO in an MSOS controls the flow of multimedia streams. A scenario is composed of a set of (timehessage-triggered) methods. Communications between MSOS's are handled by the Protocol-RTO. To provide an MSOS execution environment, we have developed a middleware named Windows Real-Time Object System (WRTOS) on the top of the Windows OS and the MuX platform. The MuX was developed by ETRI to support basic multimedia service inregaces in heterogeneous distributed systems.This approach facilitates the development of multimedia services by easy formalization of services and parameterized service generation.

Hardware approaches to fault-tolerance in designing a scalable multiprocessor system are discussed. Each node is designed to support multi-level fault-tolerance enabling a user to choose the level of fault-tolerance with a possible resource or performance penalty. Various tree-type interconnection networks using crossbar switches are compared in terms of reliability, latency, and implementation complexity. A practical duplicate interconnec#ion network with the increased reliabilitv is proposed in consideration of implementation issuets under the physical constraint.