The ITU-T Recommendation G.711 is the benchmark standard for narrowband telephony. It has been successful for many decades because of its proven voice quality, ubiquity and utility. A new ITU-T recommendation, denoted G.711.0, has been recently established defining a lossless compression for G.711 packet payloads typically found in IP networks. This paper presents a brief overview of technologies employed within the G.711.0 standard and summarizes the compression and complexity results. It is shown that G.711.0 provides greater than 50% average compression in typical service provider environments while keeping low computational complexity for the encoder/decoder pair (1.0 WMOPS average, <;1.7 WMOPS worst case) and low memory footprint (about 5k octets RAM, 5.7k octets ROM, and 3.6k program memory measured in number of basic operators).
Carbon electrode-based all-inorganic perovskite solar cells (PSCs) without hole-transport materials are attracting extensive interest due to their low cost, simple fabrication process, and high stability. Nevertheless, the conversion efficiency of carbon electrode-based PSCs is far from satisfactory owing to serious charge recombination at the inorganic perovskite/carbon interface, which mainly derives from the mismatched energy level between the inorganic perovskite film and carbon layer. Herein, a hydrophobic CuSCN film is introduced into carbon electrode-based CsPbIBr2 all-inorganic PSCs as a multifunctional interlayer between the CsPbIBr2 perovskite film and carbon electrode to form a favorable interfacial energy level alignment and protect the CsPbIBr2 perovskite from ambient moisture. It is found that introducing a CuSCN interlayer can not only enhance the hole extraction and suppress the charge recombination in carbon electrode-based CsPbIBr2 all-inorganic PSCs, but also improve the stability of the cell. Moreover, the very strong interaction between SCN−1 and Pb2+ remarkably reduces the surface defects of the CsPbIBr2 perovskite film. Consequently, the device with the CuSCN interlayer displays an improved power conversion efficiency of 7.30% in comparison with 5.19% for the device without the CuSCN interlayer and an excellent long-term stability under the ambient conditions.
A highly error resilient mode of the newly standardized 3GPP EVS speech codec is described. Compared to the AMR-WB codec and other conversational codecs, the EVS channel aware mode offers significantly improved error resilience in voice communication over packet-switched networks such as Voice-over-IP (VoIP) and Voice-over-LTE (VoLTE). The error resilience is achieved using a form of in-band forward error correction. Source-controlled coding techniques are used to identify candidate speech frames for bitrate reduction, leaving spare bits for transmission of partial copies of prior frames such that a constant bit rate is maintained. The self-contained partial copies are used to improve the error robustness in case the original primary frame is lost or discarded due to late arrival. Subjective evaluation results from ITU-T P.800 Mean Opinion Score (MOS) tests are provided, showing improved quality under channel impairments as well as negligible impact to clean channel performance.
We recorded ganzfeld scotopic ERGs to examine the responses of human rod bipolar cells in vivo, during dark adaptation recovery following bleaching exposures, as well as during adaptation to steady background lights. In order to be able to record responses at relatively early times in recovery, we utilized a 'criterion response amplitude' protocol in which the test flash strength was adjusted to elicit responses of nearly constant amplitude. In order to provide accurate and unbiased measures of response kinetics, we utilized a curve-fitting procedure to fit a smooth function to the measured responses in the vicinity of the peak, thereby extracting both the time-to-peak and the amplitude of the responses. Following bleaching exposures, the responses exhibited both desensitization and accelerated kinetics. During early post-bleach recovery, the flash sensitivity and time-to-peak varied according to a power-law expression (with an exponent of 6), as found in the presence of steady background light. This light-like phenomenon, however, appeared to be set against the backdrop of a second, more slowly recovering 'pure' desensitization, most clearly evident at late post-bleach times. The post-bleach 'equivalent background intensity' derived from measurements of flash sensitivity faded initially with an S2 slope of approximately 0.24 decades min(-1), and later as a gentle S3 tail. When calculated from kinetics, the results displayed only the S2 slope. While the recovery of rod bipolar cell response kinetics can be described accurately by a declining level of opsin in the rods, the sensitivity of these cells is reduced further than expected by this mechanism alone.
In this article, the electrogastrography is utilized to detect slow wave of gastric digest motility after test meal. In order to extract useful information, this study used multi-resolution method with the Daubechies wavelet function to decompose EGG signal into 9 layers. We reconstructed the slow wave with decomposed signal after digital signal processing to achieve method of the slow wave detection of EGG. During strong contraction of stomach, there is a significant increase in frequency spectrum and power spectrum of the slow wave frequency region. And power spectrum of time windows of slow wave bandwidth increases clearly. The contribution of this paper was that the filter of CWT and Fourier transform was used to obtain the bandwidth of slow wave, and the proposed method was compared with Chebyshev filter. By calculation and analysis of experimental data, the EGG slow wave detection method of wavelet-based motility of gastric digestion was verified to be effective, and also provided a better clinical method to monitor the state of stomach activities. This method is also can be applied to human medical sensor network which includes electrogastrography, electrocardiogram, thermometer, sphygmomanometer.
CsPbX 3 (X = I, Br) inorganic perovskite solar cells (PSCs) have been considered as one of the most appealing research topics in the fields of photovoltaic technologies in the past several years due to their excellent thermal stability and booming conversion efficiency. Nevertheless, there are still a large number of critical challenges and issues for inorganic PSCs, such as unstable phase structure of I‐rich inorganic perovskites at ambient condition, the wide bandgap of Br‐rich inorganic perovskites, and serious defect traps, hindering further development of inorganic PSCs. Recently, partially substituting Pb 2+ with other metal ions has been shown to enhance the stability, tune the bandgap, reduce the defects of CsPbX 3 inorganic perovskites, and thereby improve the photovoltaic performance of inorganic PSCs. Herein, the recent progress in improving the photovoltaic performance of inorganic PSCs through the B‐site doping strategy is summarized, and the influence of the alternative metal ions on the stability and optoelectronic properties of inorganic perovskites and photovoltaic characteristics of CsPbX 3 ‐based PSCs is discussed. Finally, the issues that need to be understood in more detail are presented. It is believed that B‐site doping offers a practical strategy to gain high‐performance perovskite photovoltaic devices.
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