Hiroshi Yasukawa

The precursor signal detection from electromagnetic waves for predicting great earthquakes using Kalman filter

The tectonic activities that precede significant earthquakes release electromagnetic (EM) waves that can be used as earthquake precursors. We have been observing EM radiation in the extremely low frequency band at over 40 observation stations in Japan for predicting significant earthquakes. However, the recorded signals contain several noise components generated from the ionosphere, human activity, and so on. Most background noise in observed signal is attributed to lightning in the tropics. In this paper, we introduce a state space model and Kalman filter to reduce the noise. The good performance of the proposed model is confirmed.

Clustering of EM radiation source based on eigenvector

Our goal is to locate anomalous electromagnetic (EM) sources caused by seismic activity for earthquake prediction. For the purpose, we have measured the EM wave of 223Hz at 35 sites in Japan. The measured signal contains much noise caused by lightning around the equator, human activity, near field lightning and so on. EM noises from far sources can be eliminated by using correlation in multi-point observation. But near-field noise is not easy to eliminate. This paper shows that the principal component analysis methods for covariance matrices of measured signals are effective for clustering signals and separating each source. It is shown that a result to estimate thunder lightning location in near field agrees with real thundercloud observed by radar system. And results of estimation of sources of anomalous EM radiation occurred before and after earthquake are also shown.

Signal detection and processing of seismic electromagnetic radiation in ELF band

In this paper, a new signal processing method appropriate for detecting electromagnetic radiation due to the earthquake activities was proposed. The radiation is usually accompanied by background noises, mainly caused by atmospheric discharges in the tropical regions. A full-band differentiating filter was applied for the received data as a preprocessing. The good performance was obtained to detect a precursor signal of an earthquake by utilizing the proposed method.

Estimation of EM radiation source in ELF band

Our goal is to locate anomalous electromagnetic (EM) source caused by seismic activity for earthquake prediction. For the purpose, we have been measured EM wave of 223 Hz at 35 sites in Japan. This paper analyses relation between EM power attenuation and distance from its source. The relation is necessary to estimate the source location.

Auditory sonification for ELF band signal of seismic electromagnetic radiation

A signal sonification method appropriate for detecting electromagnetic radiation due to the earthquake activities is developed. The radiation is usually accompanied by a background noise that is mainly caused by atmospheric discharges in the tropical regions. Data representing the seismic radiation is presented as sound via the concept of sonification. This is useful to immediately find out anomalous seismic radiation, which are often followed by a disastrous earthquake. from massive data collected from over forty observation stations. It is illustrated that the auditory display is north for the future earthquake prediction system.

Study on locating simulation of EM radiation source and transfer characteristic in ELF electromagnetic field

The Japanese Islands are located in an active position of seismic activity and therefore often have been afflicted by the damage of an earthquake. There is a report that disorder of an electro-magnetic (EM) wave occurs in nature as a precursor of crustal activity. In order to detect the sign, we have been measuring EM waves of 223 Hz at about 40 sites in Japan. Our final goal is to determine the EM source more correctly. To locate the radiation source by multi point observations of EM power, EM wave propagation characteristic needs to be clear. In the presumed method of a generation source, we assume the attenuation model that EM wave intensity declines by the /spl alpha/ power of the distance from the EM source. /spl alpha/ is an unknown value, however, this paper analyzes /spl alpha/ by locating the thundercloud position which generates the EM wave.

Study on analysis of EM radiation source based on eigenvector

Occurrence of anomalous Electro-Magnetic (EM) radiation is known as a precursor of earthquakes. Our goal is to locate anomalous EM source caused by seismic activity for earthquake prediction. For the purpose, we have been measuring EM wave of 223 Hz at about 40 sites in Japan. Measured signal contains much noise caused by far thunder lightning around equators, human activities, near field lightning and so on. This paper shows that the principal component analysis methods for covariance matrices of measured signals are effective for removing a component caused by thunder lightning around equator and for separating each EM source. Moreover, it is shown that a result of elimination of noise caused by far lightning around equators, estimation of thunder lightning location in near field agrees with real thundercloud observed by radar system, and estimation of sources of anomalous EM radiation occurred before earthquake.

A dynamic flexible grouping over CORBA-based network and its application to mobile computing

A typical management application in todays enterprise network involves remote cooperation o f a number of skilled people within and across organizations. Hence there is a need to consider the role of human resources and groups, and their interactions in a network operation and management process. However, most of the present day management solutions concentrate on the management of network equipment / devices. In view of the critical nature of many networked applications, it is important to provide effective and reliable management from the perspective of an enterprise. In addition to this, it is very useful to support flexible grouping within and across organizations. For the achievement of this flexible grouping, we adopt the Common Object Request Broker Architecture (CORBA) framework, since software design becomes easier with this framework. As an open standard for distributed object computing, CORBA provides a strong, universal, powerful framework for developing applications within distributed heterogeneous environments. CORBA specifies an Object Request Broker (ORB) as the object communication infrastructure and the Interface Definition Language (IDL) as a language for object interface specification. In this paper, we have examined some uses of CORBA for flexible grouping within and across organizations, and a prototype has been developed.