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The expectation--maximization (EM) algorithm updates all of the parameter estimates simultaneously, which is not applicable to direction of arrival (DOA) estimation in unknown nonuniform noise. In this work, we present several efficient EM-type algorithms, which update the parameter estimates sequentially, for solving both the deterministic and stochastic maximum--likelihood (ML) direction finding problems in unknown nonuniform noise. Specifically, we design a generalized EM (GEM) algorithm and a space-alternating generalized EM (SAGE) algorithm for computing the deterministic ML estimator. Simulation results show that the SAGE algorithm outperforms the GEM algorithm. Moreover, we design two SAGE algorithms for computing the stochastic ML estimator, in which the first updates the DOA estimates simultaneously while the second updates the DOA estimates sequentially. Simulation results show that the second SAGE algorithm outperforms the first one., Comment: arXiv admin note: text overlap with arXiv:2208.07510

Based on the practical need for control stick force sensor test of a certain type of aircraft, corresponding design method of control stick force sensor tester is propoesd, its basic testing principle and course are analyzed,in th end this type of tester is made and tested practically.The result shows that the control stick force sensor tester possesses the characteristics of easy manipulation, perfect function, high intelligence,fast and exact test, provides a scientific testing means for the performance of aircraft control stick force sensor,and has a good application value and popularizing prospect.

The interaction potential of a He–BH complex is investigated by the coupled-cluster single-double plus perturbative triples (CCSD (T)) method and an augmented correlation consistent polarized valence (aug-cc-pV)5Z basis set extended with a set of (3s3p2d1f1g) midbond functions. Using the five two-dimensional model potentials, the first three-dimensional interaction potential energy surface is constructed by interpolating along (r–re) by using a fourth-order polynomial. The cross sections for the rovibrational relaxation of BH in cold and ultracold collisions with 3He atom are calculated based on the three-dimensional potential. The results show that the Δν = −1 transition is more efficient than the Δν = −2 transition, and that the process of relaxation takes place mainly between rotational energy levels with the same vibration state and the Δj = −1 transition is the most efficient. The zero temperature quenching rate coefficient is finite as predicted by Wigner's law. The resonance is found to take place around 0.1–1 cm−1 translational energy, which gives rise to a step in the rate coefficients for temperatures around 0.1–1 K. The final rotational distributions in the state ν = 0 resulting from the quenching of state (ν = 1, j = 0) at three energies corresponding to the three different regimes are also given.