Nagahisa Mita

Migration routes and important resting areas of Siberian cranes (Grus leucogeranus) between northeastern Siberia and China as revealed by satellite tracking

In 1995 and 1996 thirteen Siberian cranes (Grus leucogeranus) were fitted with satellite transmitters on the breeding grounds in northeastern Siberia. Eleven of these 13 birds were successfully satellite tracked, and five of these 11 provided complete migratory information from their breeding grounds in Yakutia, Siberia, to their wintering area at Poyang Lake, in China. Several stopover sites were identified, the most important being in Qiqihar-Baicheng (China), Shuangtaizi River delta (China), and Yellow River delta (China). Birds rested more frequently in Russia than in China, suggesting availability of suitable wetland habitat in Russia and absence of adequate, suitable wetland habitat in China. Wintering habitat in China also faces numerous threats. Habitats utilized by Siberian cranes are also important to other threatened wetland birds that have been satellite-tracked recently. If Siberian crane habitat needs fail to be addressed, this critically endangered species will be further endangered.

Satellite tracking of the migration of the red‐crowned crane Grus japonensis

Autumn migration routes of red-crowned cranes, Grus japonensis, from two continental east Asian sites were documented in detail by satellite tracking. Two routes were identified: a 2200 km western route from Russia’s Khingansky Nature Reserve to coastal Jiangsu Province, China; and a 900 km eastern route from Lake Khanka (Russia) to the Korean Peninsula and the Demilitarized Zone. The most important rest-sites were identified as Panjin Marsh (China), coastal mudflats south-east of Tangshan City (China), the Yellow River mouth (China), Tumen River mouth (North Korea/China/Russia), Kumya (North Korea) and Cholwon (Korean DMZ). Movements within the wintering range were also recorded, including complex commuting between sites by individual cranes and patterns of daily movements within sites. These data should prove useful for conservation of the flyway.

Integrated Digital Rights Management for Mobile IPTV Using Broadcasting and Communications

This paper presents a digital rights management (DRM) scheme for mobile broadcasting that integrates management via broadcasting and communications. The scheme provides access control and rights protection for subscription Mobile IPTV (Internet Protocol TV), enabling transmission of contract information to control broadcasting reception via both broadcasting wave and communications. It has transmission functions that reduce the amount of contract information that has to be transmitted through broadcasting as well as a function for transmitting contract information via communications. A PC simulation indicates that the DRM scheme is effective in terms of the transmission rate required to send contract information via broadcasting wave. We also demonstrated the feasibility of the DRM scheme by using a prototype system implemented on an SIM card. The DRM scheme enables advanced mobile receiver functions such as pay-per-view with an interactivity channel using communications and a subscription TV such as pay-per-month on mobile receivers without an interactivity channel by transmitting contract information via broadcasting wave.

Circularly polarized reconfigurable patch antenna using Y-branched feed circuit

This paper is devoted to a circularly polarized patch antenna with the Y-branch feeding structure for switching circular polarization (CP) between left-hand CP (LHCP) and right-hand CP (RHCP). In this structure, the feed circuit is installed behind the ground plane because the electromagnetic distribution on the feeding line has no effect on the radiation pattern. In addition, the slot coupled structure is adopted to avoid a complicated manufacturing process like via-hole structures resulting in ease of fabrication of multi-layered structure. This provides an interest for us in the effect of the slot structure on cross-polarization discrimination (XPD) because we need two adjacent slots in the present structure.

Polarization characteristics of patch antenna using in-plane and weakly biased ferrite substrate

A square patch antenna using an in-plane biased yttrium iron garnet (YIG) polycrystalline substrate is presented. The patch antenna is fed through a cross-slot with slots of equal or unequal length to control the polarization. The experimental results reveal that the rotation direction of the elliptical polarization was switched between right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) controlling the axial ratio continuously without switching devices. The antenna gain was also investigated with respect to this polarization switching and the magnetic bias.

Nocturnal wild bird species identification by sound information using wavelet

Nocturnal wild bird species identification by sound information using wavelet is investigated. As the method, firstly, perform frequency conversion of a bird call. From there, obtained the mean value express the strength of the frequency ingredient and the modulation spectrums express the frequency of the bird call. Next, input feature quantity into the neural network for classification.

A Conditional Access System for mobile broadcasting systems

This paper presents an advanced CAS which provides access control and rights protection for mobile TV content. This advanced CAS can reduce the amount of contract information transmitted through broadcasting. We also demonstrated the feasibility of the proposed CAS by using a prototype system implemented on a SIM card.

A digital video scrambling system with variable concealed levels incorporating viewing licenses

In mobile TV with subscription broadcasting systems using wireless communications, streaming-based content services and download-based content services which play back stored content on receivers are being considered. These download-based content services require a function for playing back content in deteriorated video to encourage non-subscribers to purchase content, in addition to a function that allows only subscribers to view content. Therefore, content providers require a digital video scrambling method with variable concealed levels to control the video quality of stored content. We propose a digital video scrambling system with variable concealed levels incorporating viewing licenses. The system can handle H.264/AVC coding content, and the processing load for controlling the concealed level of video is low. We also verify by evaluating video quality and implementation that the proposed system is feasible for actual service.

Square waveguide antenna using L-shaped probe

A circularly polarized waveguide antenna using a simple feed structure is proposed and investigated. The feed probe forms L character put on a sidewall of the waveguide so that circular polarization can be generated by the traveling wave on the L-probe. This paper describes the proposed scheme and the experimental CP characteristics of waveguide antenna. Finally, simulated results by finite-difference time-domain (FDTD) method are presented.

Correction of elevation-induced errors in locations of the ARGOS satellite-tracking system

Satellite tracking is an effective way to track moving objects over long distances, and has recently been used to show the migration routes and ecology of birds. Satellite tracking data has been useful for conservation of several bird species, and therefore accurate location data are required for such work. The ARGOS satellite-tracking system requires that the elevation of a platform transmitter terminal (PTT) be estimated before a location is calculated. Extreme errors can occur if the estimated elevation is incorrect. The authors have developed two correction methods for elevation induced errors that use the estimated locations on the assumption of zero-meter elevation. First, they attached an atmospheric pressure sensor to the PTT. The true elevation of the PTT can be calculated from the atmospheric pressure data transmitted via the satellite of the ARGOS system. The elevation-induced errors can be corrected by the geometrical calculations using the data of the estimated location, spurious location, assumed elevation (0 m) and true elevation. Second, they use a global digital elevation model (DEM) GTOPO30 with a horizontal grid spacing of 30 are seconds that is offered by USGS (U. S. Geological Survey). The elevation of PTT is estimated at the location reported from the ARGOS system by use of DEM. The elevation-induced errors are reduced by the same calculation as the first method. Next, the elevation of PTT is estimated at the corrected location. Iterating these calculations, the true elevation and location can be calculated.