scispace - formally typeset
Search or ask a question

Showing papers by "Jianqing Wang published in 2016"


Journal ArticleDOI
TL;DR: A wearable electrocardiogram (ECG) which employs impulse radio (IR)-type HBC technology for transmitting vital signals on the human body in a wearable BAN scenario and its communication performance and ECG acquisition performance sufficiently showed the validity and feasibility of the HBCbased ECG for healthcare applications.
Abstract: Human body communication (HBC) provides a promising physical layer for wireless body area networks (BANs) in healthcare and medical applications, because of its low propagation loss and high security characteristics. In this study, we have developed a wearable electrocardiogram (ECG) which employs impulse radio (IR)-type HBC technology for transmitting vital signals on the human body in a wearable BAN scenario. The HBC-based wearable ECG has two excellent features. First, the wideband performance of the IR scheme contributed to very low radiation power so that the transceiver is easy to satisfy the extremely weak radio laws, which does not need a license. This feature can provide big convenience in the use and spread of the wearable ECG. Second, the realization of common use of sensing and transmitting electrodes based on time sharing and capacitive coupling largely simplified the HBC-based ECG structure and contributed to its miniaturization. To verify the validity of the HBC-based ECG, we evaluated its communication performance and ECG acquisition performance. The measured bit error rate, smaller than 10 $^{-3}$ at 1.25 Mb/s, showed a good physical layer communication performance, and the acquired ECG waveform and various heart-rate variability parameters in time and frequency domains exhibited good agreement with a commercially available radio-frequency ECG and a Holter ECG. These results sufficiently showed the validity and feasibility of the HBC-based ECG for healthcare applications. This should be the first time to have realized a real-time ECG transmission by using the HBC technology.

58 citations


Journal ArticleDOI
TL;DR: It is shown that the authors' proposed circuit structure with the third electrode directly connected to signal ground can provide an effect on common mode noise reduction similar to the usual drive-right-leg circuit, and a sufficiently good acquisition performance of ECG signals.
Abstract: Wearable electrocardiogram (ECG) is attracting much attention in daily healthcare applications, and human body communication (HBC) technology provides an evident advantage in making the sensing electrodes of ECG also working for transmission through the human body. In view of actual usage in daily life, however, non-contact electrodes to the human body are desirable. In this Letter, the authors discussed the ECG circuit structure in the HBC-based wearable ECG for removing the common mode noise when employing non-contact capacitive coupling electrodes. Through the comparison of experimental results, they have shown that the authors' proposed circuit structure with the third electrode directly connected to signal ground can provide an effect on common mode noise reduction similar to the usual drive-right-leg circuit, and a sufficiently good acquisition performance of ECG signals.

15 citations


Journal ArticleDOI
TL;DR: In this article, a transmit polarisation diversity antenna for implant UWB communications was developed and applied to a UWB-impulse radio (UWB-IR) scheme and a multiband-orthogonal frequency division multiplexing (MB-OFDM) scheme, respectively.
Abstract: In implant body area networks (BANs), an ultra-wideband (UWB) technology is a promising candidate to accomuplish high data rate. However, due to its frequency, the UWB signals suffer from large attenuation in the implant communication link. This fact suggests the difficulty on achieving reliable communication. For achieving reliable communication, it is well known that a spatial diversity technique is efficient. In this study, the authors pay attention to the fact that it is possible to further miniaturise the UWB antenna due to its very high frequency. Then, the authors aim to develop a transmit polarisation diversity antenna for implant UWB communications, and apply the developed transmit diversity system to a UWB-impulse radio (UWB-IR) scheme and a multiband-orthogonal frequency division multiplexing (MB-OFDM) scheme, respectively. For evaluating the proposed system, the authors first analyse the propagation characteristics in the implant UWB channel, using the finite difference time domain numerical analysis technique. Then, the authors evaluate and discuss the communication performances of the both modulation schemes for the transmit polarisation diversity. As a result, at a communication distance of 7 cm, the throughputs have accomplished to 300 Mbps for the MB-OFDM scheme and 30 Mbps for UWB-IR scheme, respectively.

14 citations


Journal ArticleDOI
TL;DR: The results revealed that the core temperature increased by approximately 1.5°C compared with the baseline and reached a plateau till the end of RF-EMF exposure, and the gene expression of heat-shock proteins (Hsp) and heat- shock transcription factors (Hsf) family after RF- EMF exposure was analyzed.
Abstract: We investigated the thermal effects of radiofrequency electromagnetic fields (RF-EMFs) on the variation in core temperature and gene expression of some stress markers in rats. Sprague-Dawley rats were exposed to 2.14 GHz wideband code division multiple access (W-CDMA) RF signals at a whole-body averaged specific absorption rate (WBA-SAR) of 4 W/kg, which causes behavioral disruption in laboratory animals, and 0.4 W/kg, which is the limit for the occupational exposure set by the International Commission on Non-Ionizing Radiation Protection guideline. It is important to understand the possible in vivo effects derived from RF-EMF exposures at these intensities. Because of inadequate data on real-time core temperature analyses using free-moving animal and the association between stress and thermal effects of RF-EMF exposure, we analyzed the core body temperature under nonanesthetic condition during RF-EMF exposure. The results revealed that the core temperature increased by approximately 1.5°C compared with the baseline and reached a plateau till the end of RF-EMF exposure. Furthermore, we analyzed the gene expression of heat-shock proteins (Hsp) and heat-shock transcription factors (Hsf) family after RF-EMF exposure. At WBA-SAR of 4 W/kg, some Hsp and Hsf gene expression levels were significantly upregulated in the cerebral cortex and cerebellum following exposure for 6 hr/day but were not upregulated after exposure for 3 hr/day. On the other hand, there was no significant change in the core temperature and gene expression at WBA-SAR of 0.4 W/kg. Thus, 2.14-GHz RF-EMF exposure at WBA-SAR of 4 W/kg induced increases in the core temperature and upregulation of some stress markers, particularly in the cerebellum.

12 citations


Proceedings ArticleDOI
01 Aug 2016
TL;DR: From the results, it is revealed that the sparse reconstruction is acceptable to the EM imaging-based localization, and the proposed method can estimate the location of an implant device with the accuracy of 1cm under a high signal-to-noise power ratio (SNR) condition.
Abstract: To localize implant devices accurately, it is efficient to estimate a human internal structure with incident electromagnetic waves based on an electromagnetic (EM) imaging technique. In order to realize high resolution in such a localization system, it has been pointed out that huge number of measurement points should be required. To solve this problem, we investigated the possibility to apply the sparse reconstruction to the EM imaging-based localization in order to reduce the measurement points without any deterioration in the estimation accuracy. Moreover, we evaluated the estimation accuracy of our location estimation method with the sparse reconstruction by computer simulations. From the results, it is revealed that the sparse reconstruction is acceptable to the EM imaging-based localization, and the proposed method can estimate the location of an implant device with the accuracy of 1cm under a high signal-to-noise power ratio (SNR) condition.

2 citations





Proceedings ArticleDOI
20 Mar 2016
TL;DR: To realize accurate real-time localization without pre-measured model parameters, genetic algorithm (GA) is applied into the electromagnetic imaging-based localization method and the proposed GA-based method is evaluated in terms of the location estimation as accuracy compared with the conventional methods.
Abstract: To improve the performance of a wireless capsule endoscope (WCE), it is strongly recommended to add the location information to the image data obtained by the WCE. However, there is a disadvantage that a lot of existing localization techniques require to measure channel model parameters in advance. To avoid such a burdensome pre-measurement, this paper pays attention to WCE localization based on three-dimensional (3D) electromagnetic imaging technology which can estimate not only the location but also the internal structure of a human body. On the other hand, the electromagnetic imaging with high resolution has huge computational complexity, which should prevent us from carrying out real-time localization. To realize accurate real-time localization without pre-measured model parameters, we apply genetic algorithm (GA) into the electromagnetic imaging-based localization method. Furthermore, we evaluate the proposed GA-based method in terms of the location estimation as accuracy compared with the conventional methods. In addition, we show the possibility of using the electromagnetic imaging as a WCE localization method without any burdensome pre-measurement.

1 citations



Journal ArticleDOI
TL;DR: In this paper, the authors used a simplified equivalent circuit model consisting of inductances, derived from their geometrical mean distances (GMDs) from the traces and ground patterns, and found that the calculation results also had dipping point.
Abstract: SUMMARY Electromagnetic disturbances in vehicle-mounted FM radios are mainly caused by conducted noise currents flowing through wiring harnesses from printed circuit boards (PCBs) with the slits of ground patterns. To suppress these noise currents from PCBs, we previously performed Finite-Difference Time-Domain (FDTD) simulation and measurement using multiple simple two-layer PCB models in which the ground patterns were divided into two parts with different widths, and revealed that both results agreed well with the fact that crosstalk cannot always be reduced by increasing the width of divided ground patters, but had the smallest values (dipping point) at a specific spacing between the divided ground patterns. In order to clarify the above result, we calculated crosstalk using a formula developed from a simplified equivalent circuit model consisting of inductances, derived from their geometrical mean distances (GMDs) from the traces and ground patterns, and found that the calculation results also had dipping point. However, the specific spacing and crosstalk values were different from the simulations and measurements. In the present study, to improve calculation accuracy, we considered nonuniformity of the current distribution in the ground patterns instead of a uniform current distribution, and obtained crosstalk evaluation results which agreed better with simulations and measurements.