The exposure of children to mobile phones has been a concern for years, but so far the conclusions with respect to compliance with safety standards are based only on simulations. Regulators have requested that these conclusions be supported by experimental evidence. The objectives of this study are 1) to test if the hypothesis that the specific anthropomorphic mannequin (SAM) used in standardized compliance testing is also conservative for homogeneous child head models and 2) to validate the numerical prediction of the peak spatial SAR (psSAR) in child head phantoms. To achieve these objectives, head phantoms of 3- and 8-year-old children were developed and manufactured. The results confirm that SAM is also conservative for child head phantoms, and that the agreement between numerical and experimental values are within the combined uncertainty of 0.9 dB, provided that the actual peak spatial SAR (psSAR) is determined. The results also demonstrate that the currently suggested numerical SAR averaging procedures may underestimate the actual psSAR by more than 1.3 dB and that the currently defined limits in terms of the average of a cubic mass are impractical for non-ambiguous evaluations, i.e., for achieving inter-laboratory repeatability.

One of the most important duties of government is to maintain safety. In 2007, the Ministry of Internal Affairs and Communications of Japan tested 16 different models of a safety support system for children on school routes. One of the models was constructed and tested at a school in an area of the city of Hiroshima from September to December of 2007. A consortium was established by the city of Hiroshima; Hiroshima City University; Chugoku Electric Power Co., Inc.; and KDDI Corporation to conduct this project. For the model project, we developed a new safety support system for children on school routes by using a mobile ad hoc network constructed from mobile phones with the Bluetooth function. About 500 students and 50 volunteers used this system for four months. The support system provided good performance and accuracy in maintaining the safety of students on the way to school [7]. The basic idea of the safety support system is the grouping of children and volunteers using a mobile ad hoc network. In this paper, we present an outline of this system and evaluate the performance of grouping and the effectiveness of our approach.

We have developed a Virtual Playground," which allows various activities such as virtual playground and virtual visiting areas for hospitalized children who can not usually go outside. A Virtual Playground system is composed of TV monitors, joysticks, cameras, video transmission devices, and a graphics workstation. In a Virtual Playground environment, children can experience what is impossible or difficult during their stay in a hospital. We have completed a couple of experiments already and discussed its effects.* In our recent work, we also introduced a simple version of the Cave display to the Virtual Playground system.