Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, mi...Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, middle and ring fingers of a receiver, and subsequently dots the right part of the Braille code on the Proximal Interphalangeal （PIP）joints of the same fingers. Because there is a small number of non-disabled people who are skilled in Finger Braille, deafblind people communicate in this medium only through an interpreter. We have been developing a Finger Braille recognition system using small piezoelectric accelerometers worn by the receiver To recognize the dotted positions （DIP or PIP joints）, we have made a hypothesis that the dotting on the DIP joints causes a hard impact, and the dotting on the PIP joints causes a soft impact, when the receiver＇s hand forms a natural longitudinal arch on the desk. The difference of each impact is indicated by its damping amplitude ratio. In this paper, a measurement experiment about the postures of the receiver＇s hand was conducted. The postures of the receiver＇s hand were as follows： forming the natural longitudinal arch on the desk and fully contacting the desk. As a result, the dotting on the DIP joints of both postures caused the hard impacts; the dotting on the PIP joints caused the soft impact when the receiver＇s hand formed the natural longitudinal arch; the dotting on the PIP joints caused the hard impact when the receiver＇s hand fully contacted the desk. Therefore, we could verify the hypothesis.展开更多
In this Letter, we propose a modified hybrid linear and nonlinear post-equalizer to aid pre-convergence of space–time block coding（STBC） decoding in the formulated multiple-input-single-output（MISO） visible light...In this Letter, we propose a modified hybrid linear and nonlinear post-equalizer to aid pre-convergence of space–time block coding（STBC） decoding in the formulated multiple-input-single-output（MISO） visible light communication（VLC） model. Meanwhile, we present a channel estimation algorithm, as the existing method is suboptimal. Experiments demonstrate that a data rate of 1 Gbit/s is easily achieved in 1.3 m indoor free space transmission with the bit error rate（BER） limited to 3.8 × 10^-3. Correspondingly, the Q factor can be improved to 3.13 d B compared to the pure linear equalizer case.展开更多
文摘Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, middle and ring fingers of a receiver, and subsequently dots the right part of the Braille code on the Proximal Interphalangeal （PIP）joints of the same fingers. Because there is a small number of non-disabled people who are skilled in Finger Braille, deafblind people communicate in this medium only through an interpreter. We have been developing a Finger Braille recognition system using small piezoelectric accelerometers worn by the receiver To recognize the dotted positions （DIP or PIP joints）, we have made a hypothesis that the dotting on the DIP joints causes a hard impact, and the dotting on the PIP joints causes a soft impact, when the receiver＇s hand forms a natural longitudinal arch on the desk. The difference of each impact is indicated by its damping amplitude ratio. In this paper, a measurement experiment about the postures of the receiver＇s hand was conducted. The postures of the receiver＇s hand were as follows： forming the natural longitudinal arch on the desk and fully contacting the desk. As a result, the dotting on the DIP joints of both postures caused the hard impacts; the dotting on the PIP joints caused the soft impact when the receiver＇s hand formed the natural longitudinal arch; the dotting on the PIP joints caused the hard impact when the receiver＇s hand fully contacted the desk. Therefore, we could verify the hypothesis.
基金supported by the National Natural Science Foundation of China(No.61571133)the National Key Research and Development Program of China(No.2017YFB0403603)
文摘In this Letter, we propose a modified hybrid linear and nonlinear post-equalizer to aid pre-convergence of space–time block coding（STBC） decoding in the formulated multiple-input-single-output（MISO） visible light communication（VLC） model. Meanwhile, we present a channel estimation algorithm, as the existing method is suboptimal. Experiments demonstrate that a data rate of 1 Gbit/s is easily achieved in 1.3 m indoor free space transmission with the bit error rate（BER） limited to 3.8 × 10^-3. Correspondingly, the Q factor can be improved to 3.13 d B compared to the pure linear equalizer case.
