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.

New services on trains are attracting a great deal of attention throughout Europe and Asia where trains are one of the most important forms of transportation. We introduced two information services on bullet-trains; Internet access and video. There are three technical challenges posed by seamless handover at 300 hn/h, aggregation of multiple access, and attack-tolerant communications. We proposed a network architecture to solve them based on the requirements of these services. Due to its extendibility and flexibility, new services that will be introduced in the future can be integrated easily. We are currently developing a tested for experimental evaluations.

Abstract R&D on new generation mobile network has attracted a growing interest over the world on the background of rapid market growth for 2nd and 3rd generation cellular networks and wireless LANs/MANs. The National Institute of Information and Communications Technology (NICT) started the New Generation Mobile Network Project in April 2002, and has developed fundamental technologies to enable seamless and secure integration of various wireless access networks such as existing cellular networks, wireless LANs, home networks, intelligent transport systems (ITS), the Beyond‐3G (B3G) cellular and other wireless access systems. This paper overviews the achievements of the project focusing on network and access technologies. Copyright © 2007 John Wiley & Sons, Ltd.

The next generation (NG) wireless system, called beyond 3G, is envisioned as a seamless worldwide wireless system. Handover latency is an important metric for the NG wireless system. This paper analyzes the handover latency of mobility support schemes including mobile Ethernet. We compare various mobility support schemes from multiple viewpoints. For the quantitative evaluation, we introduce an analytical network model through a Markovian model. The sequence of location update frames in four schemes, i.e., mobile Ethernet, a scheme using MPLS, a scheme using VLAN tag, and mobile IPv6, formulates the handover latency and handover costs. The combination of the latency of each switch, router, and link defines handover latency. The feature of this analysis is that it evaluates the latency of four schemes within the same model. Numerical results show mobile Ethernet achieves small handover latency. By means of analytical results concerning handover latency and handover costs, we consider the benefit of each scheme.

As the first step to developing a network controlled resource assignment architecture for mobile networks, we have evaluated the effectiveness of a predictive QoS control scheme for realtime video streaming on a mobile network that supports network-triggered handover. This scheme is based on network and application cooperation and enables video streaming applications on mobile devices and the correspondent hosts to control the data transmission rate before the handover of mobile devices according to the estimated value of the available bandwidth after handover. This scheme essentially has the ability to control the transmission rate not only of a device on handover but of other devices to offer fairness in using limited shared bandwidth. The simulation results reveal that the scheme could avoid picture frame losses and starvation of the playback buffer on mobile devices after handover.

Requirements for broadband mobile communications suggest the importance of the metropolitan area network (MAN) in beyond 3G integration. Beyond 3G accommodates radio systems including 3G, 4G and wireless LANs, and operates all-IP networks. Ethernet technology has become a suitable solution to cover all access points of various radio systems because of its simplicity and flexibility. A MAN by Ethernet, however, still has issues of scalability. The spanning tree protocol requires so much time to rebuild the tree in a change of topology, especially in a large MAN, and eventually causes much packet loss, which is intolerable to real time applications, such as voice and video, during reconfiguration. We propose a scalable spanning tree protocol (SSTP) to realize fast rebuilding of a spanning tree by applying a concept of regions and configure its parameters automatically. Our evaluation shows that SSTP is a solution for future mobile communication networks consisting of thousands of bridges.

The 3G cellular system is in business and the next generation wireless system called beyond 3G is said to come up in the market. For future wireless systems, there are activities to integrate the heterogeneous wireless accesses into all the IP network using the IP technologies. However, the enhanced IP technologies face addressing and handover related issues for mobility management and need security considerations for wireless access. We proposed the mobile Ethernet architecture based on Ethernet technologies, which provides layer 2 mobility solution, and discussed the IPv4/lPv6 independence and addressing simplicity. The architecture is scalable by reducing extra traffic in the metropolitan area where the various wireless accesses are available. In this paper, we propose a virtual MAC address scheme on the mobile Ethernet as a unique identifier of a mobile device and present a handover mechanism by the address scheme to realize fast movement across different wireless accesses within the network. We also evaluate signaling traffic by using a simulation related to mobility management on wireless access and show that the architecture based on the address scheme has scalability when it supports fast and frequent movements of mobile devices.

The 3G cellular system has infiltrated into the market and the next generation wireless system called beyond 3G is discussed at ITU-R. The beyond 3G system integrates various wireless accesses, including 3G and wireless LANs, and provides an all IP wireless solution to services that take advantage of each wireless communication of the system. Current approach to integrate wireless systems localizes wireless dependent functions and integrates all IP network using IP technologies. We propose a scalable mobile Ethernet architecture for the all IP integrated network using MAC layer technologies, such as provider bridge, RPR, and IEEE 802, and the fast vertical handover introducing common radio resource and signaling managements. We discuss network segmentation with mobility management and multicast management for the scalability of the mobile Ethernet by reducing network traffic. We evaluate the network from the viewpoint of scalability. In the evaluation, we understand that the design of the gateway switch of a segment forwarding MAC frames as an anchor point becomes effective in cases where the gateway switch of each segment cannot hold entries for all mobile terminals. We also evaluate the vertical handover as compared to the mobile IPv6 fast handover, and we understand that the fast vertical handover consumes less network resources and is flexible in having an anchor point for handover.

We have developed an adaptive receiver improved by a function which automatically identifies the modulation mode from many kinds of modulation modes. Several tests were carried out for the evaluation by PC simulation, under laboratory environment, under outdoor environment. By the evaluation tests, identification probability of 90% or better was acquired at S/N = 6 dB for BPSK, S/N = 6 dB for QPSK, S/N = 6 dB for 8PSK, S/N = 6 dB for pi/4 shift QPSK and S/N = 4 dB for 16QAM. The identification probability of the proposed algorithm was almost same under both of static and dynamic environment, although the dynamic environment was influenced by fading and multipass phenomena, etc.

A modulation parameter measurement algorithm used as support algorithm of automatic modulation identification algorithms in a radiowave monitoring system is described. Precise and fast measurement methods which measure modulation parameters, such as modulation index and the baseband filter's B/sub b/T product, are proposed. Because of the trade off of precision and process speed of modulation parameter measurement, the results of the most suitable sampling rate on the basis of experimental verifications are described.

We developed an identification algorithm that can distinguish twelve kinds of modulation modes using a blind process aimed at automatic identification of unknown modulated signals. We also developed an adaptive receiver, installed this algorithm, and we carried out an experiment to evaluate the receiver's ability. By the result of the validation experiment, for linear digital modulation modes with S/N /spl ges/ 3 dB, for GMSK of nonlinear digital modulation modes with S/N /spl ges/ 18 dB, and for the FM of analog modulation modes with S/N /spl ges/ 12 dB, we got a performance of identification probability of over 90 % respectively. Furthermore, based on the identification results, we evaluated the adaptive demodulation process by using the developed system and confirmed its effectiveness.

An optimistic consistency scheme has been established with respect to data consistency and availability in distributed systems. Wireless networks are becoming popular in data communication and suitable for data sharing among users using multicast capability, but have hidden node problems. This paper proposes a simple data coherency protocol for mobile devices that has less data traffic in data collaboration using a multicast communication feature and is capable of automatic recovery from unpredictable disconnection, such as hidden node problems, by a data versioning scheme using a version vector and update log management. We evaluated the efficiency of data sharing over multicast communication and the recovery cost from failure caused by hidden nodes and confirmed the efficiency of the protocol.

To supplement the existing signaling system, devices that prevent head-on collisions, warn maintenance workers on the wayside of approaching trains, and prevent trains from operating over the allowable speed limit were produced by way of trial and error and their performance were evaluated. In the case of head-on collisions prevention, a train's running position is located by a tachometer generator to determine its position in relation to other trains and by a global positioning system (GPS) to determine its absolute position. In addition, train radios with multichannel UHF transmission are adopted to provide direct communication between trains without the use of control stations along the wayside. For controlling the train speed, constant comparisons between the allowable maximum speed and actual train speeds along a line are carried out using an IC-card that enables a train to judge for itself whether or not it is speeding. Judging from the test results, a stable distance for data transmission between trains is about 2,000 m in a plain area, which is sufficient for securing the minimum distance of 1200 m necessary to prevent the head-on collision of two trains. In addition, it was discovered that a maximum of 10 trains could be operated on one carrier wave of a train radio when the scanning time of the data transmission is fixed at 2 seconds.