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Acoustic positioning and navigation technology is the main technical means for underwater target location and navigation systems, where the precision of time delay estimation is the key. This paper proposes a time delay estimation algorithm with robustness for time-varying and multipath fading channels. Based on generalized cross correlation algorithm, normalized correlation peak envelope ratio is got. Using time-frequency analysis, it also gets two additional features of signal, which are the short-term energy ratio and sub-band energy ratio. It recognizes the desired signal smartly and detects the direct wave accurately. Under the same detection probability, the false alarm probability is greatly reduced. Simulation and lake test results verify that the detection probability is 100% and probability of false alarm and missed detection is 0% when the signal to noise ratio is larger than-5 dB.

In order to explore the influence of temperature on track circuit, a mathematical simulation model of track circuit is established. Then, the influence mechanism of temperature on the key equipment of track circuit is analysed. Finally, the influence on the receiver voltage and the locomotive signal current are computed based on the simulation model.

The UWA channel is characterized as a time-dispersive rapidly fading channel, which in addition exhibits Doppler instabilities. To eliminate inter-symbol interference caused by multipath propagation, spatial diversity equalization is the main technical means. This paper mainly uses the method of complex weighted coefficient to achieve high SNR signal and maximize array gain. This paper uses the passive-phase-conjugation (PPC) algorithm to calculate signal-to-noise ratio(SNR) and signal-to-interference ratio(SIR) with impulse response function and communication signal. This paper firstly calculates the signal-to-noise-plus-interference ratio (SNIR) and uses the Sigmoid function to optimize the weighted coefficients of each channel. Secondly, the optimized weighted coefficients need to be normalized. It implements space and time joint equalization. Thirdly, by introducing the second order phase locked loop, it can track signal phase change caused by UWA channel. Lastly, the paper adopts fractional-decision feedback diversity equalizer(FDFDE). It achieves diversity equalization by using different channel weighted coefficients. The simulation and lake trial data processing results show that, the optimized diversity receiving equalization algorithm can improve communication system's ability in tracking the change of underwater acoustic channel, offset the impact of multipath and noise, and improve the performance of communication system. The performance of the communication receiving system is better than that of the combination with equal gain. At the same time, the bit error rate (BER) reduces for 1.7%.

We present the results for CAPRI Round 30, the first joint CASP-CAPRI experiment, which brought together experts from the protein structure prediction and protein-protein docking communities. The Round comprised 25 targets from amongst those submitted for the CASP11 prediction experiment of 2014. The targets included mostly homodimers, a few homotetramers, and two heterodimers, and comprised protein chains that could readily be modeled using templates from the Protein Data Bank. On average 24 CAPRI groups and 7 CASP groups submitted docking predictions for each target, and 12 CAPRI groups per target participated in the CAPRI scoring experiment. In total more than 9500 models were assessed against the 3D structures of the corresponding target complexes. Results show that the prediction of homodimer assemblies by homology modeling techniques and docking calculations is quite successful for targets featuring large enough subunit interfaces to represent stable associations. Targets with ambiguous or inaccurate oligomeric state assignments, often featuring crystal contact-sized interfaces, represented a confounding factor. For those, a much poorer prediction performance was achieved, while nonetheless often providing helpful clues on the correct oligomeric state of the protein. The prediction performance was very poor for genuine tetrameric targets, where the inaccuracy of the homology-built subunit models and the smaller pair-wise interfaces severely limited the ability to derive the correct assembly mode. Our analysis also shows that docking procedures tend to perform better than standard homology modeling techniques and that highly accurate models of the protein components are not always required to identify their association modes with acceptable accuracy. Proteins 2016; 84(Suppl 1):323-348. © 2016 Wiley Periodicals, Inc.

The loss tangent and storage modulus of cement mortar containing treated silica fume and styrene-acrylic are measured. Shaking table tests on three groups of 1/4 models of high damping concrete frames are conducted to compare the effects of reducing vibration. A relationship between the viscosity coefficient of high damping concrete and the damping coefficient of structure is established by analyzing dynamic parameters like damping ratio and frequency, and comparing responses of relative displacement and absolute acceleration. Surface treatment of silica fume and styrene-acrylic emulsion prior to incorporation in a cement mortar increases the loss tangent of the resulting composite by 40–400% as compared to the cement mortar without any admixtures, and the damping ratio of the reinforced concrete is raised by 7%–9%. In addition, a theoretical method of determining the viscosity coefficient of the material on the basis of shaking table test results is put forward.