In this paper, we propose a design method of hierarchical decentralized observers for networked linear systems. In this method, based on suitable state-space expansion of the network systems, we, first, find a high-dimensional dynamical compensator that can achieve any desirable performance for decentralized state estimation. Next, fully taking advantage of model reduction techniques, we extract a subspace that is essentially relevant to the decentralized state estimation, from the high-dimensional state-space of the dynamical compensator. This procedure successfully yields a lower-dimensional compensator that guarantees not only the stability of the estimation error but also a desirable estimation performance with respect to the system behavior for external input signals. The effectiveness of the proposed method is shown through an application to the state estimation of power networks.
In order to construct a model which can describe levels of skillfulness of drivers, a driver model of target speed tracking driving is proposed. The model is constructed under two requirements. One is that functions of recognition, decision and operation of a driver are able to interpreted. The other is that the model can express experience of environments. To satisfy the requirements, the proposed model consists of recognition, decision and operation modules and modules of knowledges of environment. Through some computational simulations using a typical mode of target speed tracking, the basic properties of the proposed model have been investigated, and parameters of an experienced driver and a beginner driver are estimated. Using the parameters, it has been shown that the proposed model can represent features of both a novice driver and an experienced skillful driver.
In general GPS positioning, ranging errors due to the ionosphere are corrected by so-called Klobuchar’s ionospheric model. However, it is well known that the model may correct about only 50[%] RMS ionospheric errors. On the other hand, it is reported that SCHA (Spherical Cap Hamonics Analysis) ionosphere model well works in a regional area such as the sky over Japan. In this paper, therefore, we propose a method to provide more accurate parameters of the regional Klobuchar model based on SCHA ionosphere model.