Japan Aerospace Exploration Agency (JAXA) has some instruments aboard satellites for understanding of marine context. Two satellite-based automatic identification system (AIS) receivers, named SPace-based AIS Experiment 1 (SPAISE1) on the Small Demonstration Satellite-4 (SDS-4) and SPAISE2 on the Advanced Land Observing Satellite-2 (ALOS-2) has the wide observation coverage to enable to support a wide range of search and rescue and traffic monitoring activities and to assist with maritime security. ALOS-2 is also equipped with the Panchromatic L-band Synthetic Aperture Radar (PALSAR-2) that has the special feature of being able to make observations of ships, including no signal transmission of AIS. Simultaneous observations with SPAISE2 and PALSAR-2 on the identical satellite bring both individual ship information and fleet distribution including small ships with no AIS signals. Satellite-based AIS systems and SAR ship detection technique combined with sea surface temperature (SST) and other parameters derived from earth observation satellites (e.g. Global Change Observation Mission - Water (GCOMW)) can provide the detailed distributions of ships and fleets with environmental information.

Non-communicable diseases (NCDs) are no longer just a problem for high-income countries, but they are also a problem that affects developing countries. Preventive medicine is definitely the key to combat NCDs; however, the cost of preventive programs is a critical issue affecting the popularization of these medicine programs in developing countries. In this study, we investigate predictive modeling for providing a low-cost preventive medicine program. In our two-year-long field study in Bangladesh, we collected the health checkup results of 15,075 subjects, the data of 6,607 prescriptions, and the follow-up examination results of 2,109 subjects. We address three prediction problems, namely subject risk prediction, drug recommendation, and future risk prediction, by using machine learning techniques; our multiple-classifier approach successfully reduced the costs of health checkups, a multi-task learning method provided accurate recommendation for specific types of drugs, and an active learning method achieved an efficient assignment of healthcare workers for the follow-up care of subjects.

A dual Ka-band radar system was developed by the Japan Aerospace Exploration Agency for GPM/DPR algorithm development. The system consists of two identical Ka-band radars. Both the equivalent radar reflectivity factor (Ze) and specific attenuation (k) can be estimated at each range of the path. The estimated k-Zerelations of rain, snow, and the melting layer can be used for the GPM/DPR algorithm development. Those parameters of snow at Ka band are important. Observations using the dual Ka radar system were performed in Okinawa Island, and Nagaoka, Niigata, Japan. In Okinawa Island, rain observation was conducted for confirming the performance of the measurement, and reasonable k-Zerelations of rain were obtained. In Nagaoka, snow observation was conducted. Different k-Zerelations were obtained. This was attributed to the attenuation difference between wet and dry snow.

We have analyzed rainfall data observed by Precipitation Radar (PR) on board Tropical Precipitation Measuring Mission (TRMM) to compare with the data from AMeDAS ground rain gauge network in Japan. PR has observed latitudes of 35°N-35°S and visited Japan a few times a day. Annual rainfall amounts of 1998-2008, excluding 2001, are calculated in boxes of area size of 0.5°×0.5°-3°×3° and more. It is found that PR rainfall amounts are smaller than the Automated Meteorological Data Acquisition System (AMeDAS) rainfall amounts over Japan (~-23% in the wide area). We also estimated sampling errors and retrieval errors respectively, and found that sampling errors are sufficiently small in large areas, and retrieval errors are large and account for most of all errors. In addition, retrieval errors are small in the Seto inland sea area with light rainfall, and large in the Pacific Ocean side with heavy rainfall and the mountain district with heavy snowfall. Retrieval errors seem to depend on the rain system and geographical features. In order to investigate factors caused large errors, PR and AMeDAS rainfalls observed in same times are compared. It shows that PR has a tendency to underestimate heavy rain over 10mm/h.

We have developed the GPM/DPR synthetic data from the TRMM/PR data for contribution to higher level algorithm development. The frequency of the PR is 13.8 GHz and it is necessary to estimate radar reflectivity factor (Z-factor) at the DPR frequencies. In this paper, Z-factors from rainfall signals are estimated at the DPR frequencies. The detectable rain range of the DPR is verified using the synthetic data from the PR observations on January and July 1998, which suggests that it is important to consider differences of the sensitivity between the KuPR-matched beams and the interlaced high-sensitivity beams of the KaPR. The estimation of the Z-factors at the DPR frequencies is applied to an experimental data on 15th March 2007 when the PR was operated according to the scanning geometry of the KaPR, and then the synthetic data are obtained with distinction of 2 kinds of KaPR beams.

A dual Ka-band radar system is developed by the Japan Aerospace Exploration Agency (JAXA) for the Global Precipitation Measurement (GPM) dual-wavelength radar (DPR) algorithm development. The usage of the system is to measure backscattering and extinction cross sections by precipitation separately, and to provide testbed data for DPR algorithm. The parameters required in the DPR algorithm are raindrop size distribution for the liquid precipitation, and particle density, shape, and melting ratio for the solid precipitation. When the two Ka-radar systems separated by 10-20 km observe precipitation in between two radars, the specific attenuation can be measured. Along with other radar, a C-band radar, Mie scattering effect which is deviation from Rayleigh scattering could be estimated. A field experiment using the dual Ka-radar system is conducted in Okinawa Island. A C-band polarization Doppler radar is also operated, and preliminary result is presented.

This study demonstrated preliminary results in diagnosis of the numerical model with reference to the TRMM/PR, examples of the GPM/DPR synthetic data, and application of the synthetic data to the algorithm development in the nonuniform beamfilling correction method. These were performed using a satellite radar simulation algorithm by the National Institute of Information and Communications Technology (NICT) and the Japan Aerospace Exploration Agency (JAXA) named as the Integrated Satellite Observation Simulator for Radar (ISOSIM-Radar) and a cloud-resolving model by the Japan Meteorological Agency (JMA-NHM).

Global Precipitation Measurement (GPM) started as an international mission and follow-on mission of the TRMM project to obtain more accurate and frequent observations of precipitation. The accurate measurement of precipitation will be achieved by the Dual-frequency Precipitation Radar (DPR) installed on the GPM core satellite. DPR consists of two radars, which are Ku-band (13.6 GHz) precipitation radar (KuPR) and Ka-band (35.5 GHz) radar (KaPR). Level 1 algorithm, which calculates engineering values, for processing the products of each KuPR and KaPR will be developed based on the PR level 1 algorithm. Japan Aerospace Exploration Agency (JAXA) is developing level 1 algorithm. Housekeeping (HK) and science telemetry data of the DPR is basically similar to that of PR except for pulse repetition frequency (PRF) and noise sampling. DPR will use variable PRF (VPRF) technique to obtain higher sensitivity under the limited resources on the spacecraft. Sampling methods of noise for each angle are different between PR and DPR. The information of VPRF table and noise sampling will be added to level 1 products of KuPR and KaPR. KaPR sampling simulation experiment using TRMM PR was carried out for half-day on 15 March 2007 to get the same geometry data of KaPR scanning in order to create synthetic data of level 1 products for development of higher-level algorithms of DPR and examine to make the best use of them in the critical design, operation and algorithm development for DPR. It successfully finished and we could get the simulation data with same geometry of KaPR scanning.

One effort in developing the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) data processing algorithm is to correct the PR received power for mismatched-beam data after the orbit is boosted. The current standard algorithm employs a beam-mismatch correction algorithm based on the rain-echo radar equation (Takahashi's method). However, there remains a need for improving the estimated power of the mismatched-pulse echo returned from the Earth's surface and weak rain because the echo is represented with the surface-echo radar equation and the noise-power level. The error in Takahashi's method causes a negative bias (around 1 dB) in the PR received power near the main lobe clutter. This paper formulates an improved estimate of the mismatched pulse based on the rain-echo radar equation and the surface-echo radar equation for a flat-Earth surface. The improved estimate is then evaluated numerically and experimentally with the actual data obtained by TRMM/PR for observations over the ocean. The consistency of TRMM/PR data sets between preboost and postboost was improved by eliminating the negative bias (around 1 dB) in the PR received power. The mean rain rate near the surface-echo range increases by 10%, and the angle-bin asymmetry of the mean rainfall rate, which is present in the postboost data corrected by Takahashi's method, is resolved.

The rainfall amount estimated by PR shows a decrease after the satellite altitude was changed from 350 to 402.5 km in August 2001 to extend its lifetime. The major causes of the changes in rain estimates by the orbit boost are 1) the sensitivity degradation by the increase of satellite altitude, 2) the increase of the range of surface clutter by the increase of the footprint size, and 3) the mismatch between the transmission and reception angles for one pulse in every 32 pulses The decrease of the echo signal strength by the change of the satellite altitude from 350 km to 402.5 km is 1.21dB (= 20log(402.5/350)). From a simulation result, we estimate a decrease of 0.50 % in the surface rainfall estimates by the sensitivity degradation. Because the heights of clutter free bottom have increased at the off-nadir by the increase of the footprint size from 4.3 km to 5.0km, the sampling range bins for near-surface rain have raised and the PR misses low rain systems more often after the boost than before the boost. A beam mismatch correction is executed in the current 1B21 algorithm, but the correction algorithm still has a small problem and rain rate estimates near the surface in the second-half of the PR scan tend to be smaller than those in the first-half on average.

To derive the sub-footprint scale sigma0from TRMM/PR observation datasets, a new formulation to calculate the sub-footprint sigma0is devised. The sub-footprint scale sigma0would be useful to, (1) relieve the underestimate of the path integrated attenuation (PIA) at off-nadir angle observations over land, and (2) examine the nonuniformity of rainfall. The PIA estimated from sigma0of the standard product "2A21" tends to be biased toward small at off-nadir angle observations over land. Because 2-6 sub-footprint scale sigma0exists within one instantaneous field of view (IFOV), sigma0at the surface echo peak is likely unrepresentative for the IFOV especially for observations over land, depending on the surface conditions and the nonuniformity of rain. The underestimate of PIA can be relieved by averaging the subfootprint scale sigma0over the IFOV (5 km by 5 km) for each angle bins. The effect of the unbiased PIA, estimated with the sub-footprint scale sigma0, on the rain rate estimate is examined. The result shows about 10% increase of the rain rate at off-nadir angle observations over land.

Remote surgery is one of the most desired applications in the context of recent advanced medical technologies. For a future expansion of remote surgery, it is important to use conventional network infrastructures such as Internet. However, using such conventional network infrastructures, we are confronting time-delay problems of data transmission. In this paper, a remote surgery experiment between Japan and Thailand using a research and development Internet is presented. In the experiment, the image and audio information was transmitted by a newly developed low latency CODEC system to shorten the time-delay. By introducing the low latency CODEC system, the time-delay was shortened compared with the past remote surgery experiments despite the longer distance. We also conducted several network measurements such as a comparison between TCP/IP and UDP/IP about the control signal transmission.

In August 2001, the orbit of the tropical rainfall measuring mission (TRMM) satellite has been boosted from the altitude of 350 km to 400 km to extend its life time. The time delay between transmission of pulses and reception from rain/surface echoes occurs by one inter pulse period (IPP) [1]. Due to this time delay, one pulse transmitted at N — Ith angle bin is received at the receiving time gate of the next angle bin N. So the mismatch occurs between the transmitting antenna beam direction and the receiving antenna beam direction. This causes antenna gain reduction by 6 dB and leakage of rain/surface echo from the N — Ith angle bin to the Nth angle bin. In this paper, the modified beam mismatch correction algorithm is tested numerically, then it’s applied to the standard algorithm of TRMM/precipitation radar to reduce the correction error of the current beam mismatch correction algorithm.

Several robotic surgical systems have been developed for MIS (minimally invasive surgery) including commercialized products such as da Vinci and ZEUS. We have developed a minimally invasive surgical system, which have carried out remote surgery experiments for five times at the writing time. In this paper, a remote surgery experiment, which was conducted between Japan and Korea by using the developed minimally invasive surgical system is described. Research & Development (R & D) Internet testbet, APII (Asia-Pacific Information Infrastructure), which consists of an optical submarine cable network KJCN (Korea-Japan Cable Network), was used. In the experiment, a laparoscopic cholecystectomy was successfully carried out on a pig. The network time-delays of control signal and images were 6.5 msec and 435.5 msec respectively. A comparison of remote surgery experiments using ISDN and the Internet was studied

After the great success of the Tropical Rainfall Measuring Mission (TRMM), Global Precipitation Measurement (GPM) started as an international mission and follow-on mission of the TRMM project to obtain more accurate and frequent observations of precipitation. The accurate measurement of precipitation will be achieved by the DPR installed on the GPM core satellite. In order to estimate accurate precipitation rate value, calibration and validation of the DPR algorithms and products are essential. From the experiences of TRMM validations, it is important for the DPR algorithm validation to compare between precipitation rate through the calculation of DPR algorithm and that of the directly observed precipitation rate over the validation site. For this purpose, the most important and difficult issue is to construct the database of the physical parameters for the precipitation retrieval algorithms of DPR from the ground-based data using well-calibrated instruments.

We have established a medical network in Asia-Pacific area with high-quality moving image on a super broad-banded Internet line since February 2003. Broadcasting real-time surgery and teleconference with medical-quality videos with digital video transport system (DVTS) were so useful to learn surgical techniques and other medical procedures beyond borders. We have conducted 20 events in categories of teleconference (8 times), live transmission of medical procedure (6 times), and remote attendance to scientific medical meetings (6 times) until September 2004. We had teleconferences among 3 countries in APAN-Hawaii in January 2004 (Japan, Korea and USA), and in APAN-Cairns in July 2004 (Japan, Korea and Australia). There have been no serious transmission/ethical problems so far. With these experiences and current achievements, we hope to extend this advanced network system to whole Asia-Pacific countries to share medical skills and knowledge.