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This work proposes a new multi-user detection scheme based on ubiquitous antennas for co-channel heterogeneous radio signals, which are generated from different kinds of wireless services in the same frequency band. The ubiquitous antenna system is composed of multiple radio base stations (RBSs), the central control station (CCS) and radio-on-fiber (RoF) link. Computer simulation results show that the multi-user detector employing the minimum mean square error (MMSE) based combiner and the successive interference canceller (SIC) in combination can achieve the coexistence of coded orthogonal frequency division multiplexing (COFDM) and direct sequence spread spectrum (DSSS) signals.

Presented here are new optical head and optical disk technologies for an HD DVD system. The former include DVD- and CD-compatible optics and a radial tilt detection method, while the latter include new "low-to-high" media and the application of HD DVD rewritable disk format specifications.

For pt.2 see Proc. 22nd Asian conference Remote sensing, vol.1 (Nov 2001). Danger regarding the wooden building overcrowdedness has already been pursued by two analyses by GIS and Remote Sensing (by TM only) in the case study of the Great Hanshin Earthquake 1995. WHO proposed, "It is necessary to secure the citizens' healthy life and create the healthy city". At present, because of the wooden building overcrowdedness in urban areas of Tokyo Bay, there are several unhealthy districts there. Therefore, an unhealthy district should be remodelled into a healthy city in the urban planning according to the WHO proposal. The healthy city level of urban areas of Tokyo Bay was evaluated from two analyses using GIS and Remote Sensing by TM & IKONOS. This study does detailed analysis of two areas to detect the degree of wooden building overcrowdedness by using only Remote Sensing Analysis by TM & IKONOS. Two indices of the vegetation and the urbanization were considered how there was effectiveness as a disaster prevention project index in two selected municipal districts.

In high density optical disk systems employing blue laser diodes, high NA (numerical aperture) objective lenses and thin cover layer disks, compatibility with conventional DVDs and CDs is strongly required. The authors have previously proposed a blue/DVD/CD compatible optical head, whose NA for the blue optical disk is 0.7. On the other hand, NA 0.85 single objective lenses have also become available, which are suitable for the compatibility requirements because of the long working distance. So, this paper further proposes a blue/DVD/CD compatible optical head, whose NA for the blue optical disk is 0.85. In order to realize the compatibility between different types of disks, it is necessary to correct the spherical aberration and control the NA for each disk. In this three-wavelength optical head, the spherical aberration is corrected by variable magnification, and the NA is controlled by a wavelength selective aperture.

Disturbance rejection is becoming more and more important as optical disk players are being utilized in more applications. The paper considers the design of a tracking servo controller for a CD player using the disturbance observer (DOB) theory. By adding a DOB to the conventional PID controller, the tracking performance is dramatically improved in the presence of sinusoidal vibrations or a shock disturbance. The effectiveness of the DOB is verified by experimentation using an actual CD player as well as by computer simulations.

One of the most useful applications for an optical disk is a digital still camera (DSC). It is widely recognized that the vibration/shock caused by the motion of these devices is a serious problem for a portable CD (compact disk) or MD (mini disk) player. As far as a DSC with a recordable optical disk is concerned, if is far more important to reduce the effect of the disturbances in order not to fail to write data properly in the presence of even a strong disturbance. In this paper the disturbance observer has been implemented on a new recordable optical disk drive for DSC and some remarkable simulation and experimental results are shown.