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Recently, user demands for integrated searches over different information sources have been increasing rapidly. However, it is not easy to seamlessly integrate distributed heterogeneous information retrieval systems. In particular, resolving the discrepancies in the structures and semantics in the databases that are to be integrated is one of the most challenging research issues. In this paper, we propose an iKRISTAL system that integrates distributed, heterogeneous information retrieval systems without requiring source code-level modifications of the participating systems. The key element of our approach to address the structural and semantic discrepancies is to make use of schema mapping and a standardized framework for metadata registry. We have implemented and deployed a prototype implementation that integrates six different information sources, each of which is built upon heterogeneous schemas. Furthermore, we evaluated the performance of our approach under various configurations.

Network service-based computation is a promising paradigm for both scientific and engineering, and enterprise computing. The network service allows users to focus on their application and obtain services when needed, simply by invoking the service across the network. In this paper, we show that an adaptive, general-purpose run-time infrastructure in support of effective resource management can be built for a wide range of high-end network services running in a single-site cluster and in a Grid. The primary components of the run-time infrastructure are: (1) dynamic performance prediction; (2) adaptive intra-site resource management; and (3) adaptive inter-site resource management. The novel aspect of our approach is that the run-time system is able to dynamically select the most appropriate performance predictor or resource management strategy over time. This capability not only improves the performance, but also makes the infrastructure reusable across different high-end services. To evaluate the effectiveness and applicability of our approach, we have transformed two different classes of high-end applications-data parallel and distributed applications-into network services using the infrastructure. The experimental results show that the network services running on the infrastructure significantly reduce the overall service times under dynamically varying circumstances.

A tunable vibratory microgyroscope has been fabricated by surface-micromachining technology. The 7.5 μm thick polysilicon structural layer is deposited using LPCVD at 625 °C. The resonance frequency in the detection mode is designed to be higher than that in the driving mode so that the gyroscope could be matched to the resonance frequencies by applying an inter-plate d.c. bias. The gyroscope is driven in a resonant state by electrostatic force and the output detected is due to a capacitance change between the plate and the polysilicon electrode. The resonance frequencies of the gyroscope in the driving and detection directions are measured to be 10.48 and 10.93 kHz, respectively. The resonance frequency in the detection direction can be shifted to 10.52 kHz by applying a tuning voltage of 4.0 V. The quality factor and resonance frequency of the detection mode are significantly affected by ambient pressure. The electrical noise equivalent rate of this device is about 0.1 ° s −1 at 10 −2 torr.