Current Issue : July - September Volume : 2020 Issue Number : 3 Articles : 5 Articles
Aiming at the shortcomings of traditional broadcast transmitter noise test methods, such as low efficiency, inconvenient data\nstorage, and high requirements for testers, a dynamic online test method for transmitter noise is proposed. The principle of system\ncomposition and test method is given. The transmitter noise is real-time changing. The Voice Active Detection (VAD) noise\nestimation algorithm cannot track the transmitter noise change in real time. This paper proposes a combined noise estimation\nalgorithm for VAD and dynamic estimation. By setting the threshold of the double-threshold VAD detection to be low, it can\naccurately detect the silent segment. The silent segment is used as a noise signal for noise estimation. For the nonsilent segment\ndetected by the VAD, a minimum value search dynamic spectrum estimation algorithm based on the existence probability of the\nspeech (IMCRA) is used for noise estimation. Transmitter noise is measured by calculating the noise figure (NF).The test method\ncollects the input and output data of the transmitter in real time, which has better accuracy and real-time performance, and the\nfeasibility of the method is verified by experimental simulation....
Taking into account the startup behaviour of following vehicles in the waiting\narea of urban traffic signal, we propose an extended Nagel-Schreckenberg\nmodel for single-lane traffic flow, in which the dynamic behavior of each vehicle\ndepends on not only its own headway but also the headway of the immediately\npreceding one. The numerical simulation of the present model reproduces\nsome complicated nonlinear phenomena observed in real traffic\nsuch as free flow, ghostly blockage, synchronized flow and so on. For specific\nparameter combinations the flow-density relation of this model shows two\nmeta-stable branches near the transition density from free flow to wide moving\ntraffic jam. Finally, the analytical results of the model under some specific\nparameters are given by using the mean field theory....
Creep property is an important mechanical property of rocks. Given the complexity of rock masses, mechanical parameters\nchange with time in the creep process. In this work, a nonlinear function for describing the time-dependent change of parameters\nwas introduced and an improved variable-parameter nonlinear Nishihara shear creep model of rocks was established. By creating\nrock-like materials, the mechanical properties of rocks under the shear creep test condition were studied, and the deformation\ncharacteristics and long-term shear strength of rocks during creep were analyzed. The material parameters of the model were\nidentified using the creep test results. Comparison of the modelâ??s calculated values and experimental data indicated that the model\ncan describe the creep characteristics of rocks well, thus proving the correctness and rationality of the improved model. During\nshear creep, the mechanical properties of rocks have an aging effect and show hardening characteristics under low shear stress.\nFurthermore, according to the fact that Gk of the nonlinear model can characterize the creep deformation resistance, a method to\ndetermine the long-term shear strength is proposed....
Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable\nselection as well as for handling the multicollinearity problem simultaneously\nin the linear regression model. LASSO produces estimates having\nhigh variance if the number of predictors is higher than the number of observations\nand if high multicollinearity exists among the predictor variables.\nTo handle this problem, Elastic Net (ENet) estimator was introduced by\ncombining LASSO and Ridge estimator (RE).............................
Modeling watershed hydrological processes are important for water resources\nplanning, development, and management. In this study, the MIKE 11-NAM\n(Nedbor-Afstromings Model model) was evaluated for simulation of streamflow\nfrom the Bina basin located in the Madhya Pradesh State of India...............................
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