No abstract

Intrabody communication (IBC) is a wireless communication technology using the human body to develop body area networks (BANs) for remote and ubiquitous monitoring. IBC uses living tissues as a transmission medium, achieving power-saving and miniaturized transceivers, making communications more robust against external interference and attacks on the privacy of transmitted data. Due to these advantages, IBC has been included as a third physical layer in the IEEE 802.15.6 standard for wireless body area networks (WBANs) designated as Human Body Communication (HBC). Further research is needed to compare both methods depending on the characteristics of IBC application. Challenges remain for an optimal deployment of IBC technology, such as the effect of long-term use in the human body, communication optimization through more realistic models, the influence of both anthropometric characteristics and the subject's movement on the transmission performance, standardization of communications, and development of small-size and energy-efficient prototypes with increased data rate. The purpose of this work is to provide an indepth overview of recent advances and future challenges in human body/intrabody communication for wireless communications and mobile computing.

The quality of satellite radar altimetric data is very important in studies of geodesy, geophysics, and oceanography. Over coastal oceans, altimeter waveforms are contaminated by the terrain and physical environments so that the accuracy of altimeter data is lower than that over open oceans. Here we develop a new multi-subwaveform parametric retracker (MSPR) to improve the quality of altimeter data for the recovery of gravity anomaly in coastal oceans. The least squares collocation method is used to recover the residual gravity anomaly over the coastal water from altimetric data. The waveform data records from Geosat/GM around Taiwan Island are practically retracked with MSPR. When compared with the Taiwan geoid height, the results retracked by MSPR are more accurate than those retracked by the well-known β-5-parmeter method and from the geophysical data records (GDRs). The gravity anomalies over Taiwan coastal waters are calculated from the retracked altimeter data with the least squares collocation. When we compared gravity anomalies computed using altimeter GDRs with the ship-borne gravity data over Taiwan coastal ocean, we found that the results from retracked data are more accurate than those from GDRs. multi-subwaveform parametric retracker, waveform retracking for radar satellite altimetry, gravity anomaly, least squares collocation, Geosat/GM Citation:Guo J Y, Gao Y G, Hwang C W, et al. A multi-subwaveform parametric retracker of the radar satellite altimetric waveform and recovery of gravity anomalies over coastal oceans.

Existing research on human channel modeling of galvanic coupling intra-body communication (IBC) is primarily focused on the human body itself. Although galvanic coupling IBC is less disturbed by external influences during signal transmission, there are inevitable factors in real measurement scenarios such as the parasitic impedance of electrodes, impedance matching of the transceiver, etc. which might lead to deviations between the human model and the in vivo measurements. This paper proposes a field-circuit finite element method (FEM) model of galvanic coupling IBC in a real measurement environment to estimate the human channel gain. First an anisotropic concentric cylinder model of the electric field intra-body communication for human limbs was developed based on the galvanic method. Then the electric field model was combined with several impedance elements, which were equivalent in terms of parasitic impedance of the electrodes, input and output impedance of the transceiver, establishing a field-circuit FEM model. The results indicated that a circuit module equivalent to external factors can be added to the field-circuit model, which makes this model more complete, and the estimations based on the proposed field-circuit are in better agreement with the corresponding measurement results.