Beyond Universal Transformer: block reusing with adaptor in Transformer for automatic speech recognition

Transformer-based models have recently made significant achievements in the application of end-to-end (E2E) automatic speech recognition (ASR). It is possible to deploy the E2E ASR system on smart devices with the help of Transformer-based models. While these models still have the disadvantage of requiring a large number of model parameters. To overcome the drawback of universal Transformer models for the application of ASR on edge devices, we propose a solution that can reuse the block in Transformer models for the occasion of the small footprint ASR system, which meets the objective of accommodating resource limitations without compromising recognition accuracy. Specifically, we design a novel block-reusing strategy for speech Transformer (BRST) to enhance the effectiveness of parameters and propose an adapter module (ADM) that can produce a compact and adaptable model with only a few additional trainable parameters accompanying each reusing block. We conducted an experiment with the proposed method on the public AISHELL-1 corpus, and the results show that the proposed approach achieves the character error rate (CER) of 9.3%/6.63% with only 7.6M/8.3M parameters without and with the ADM, respectively. In addition, we also make a deeper analysis to show the effect of ADM in the general block-reusing method

Echoes from black bounces surrounded by the string cloud

In the string theory, the fundamental blocks of nature are not particles but one-dimensional strings. Therefore, a generalization of this idea is to think of it as a cloud of strings. Rodrigues et al. embedded the black bounces spacetime into the string cloud, which demonstrates that the existence of the string cloud makes the Bardeen black hole singular, while the black bounces spacetime remains regular. On the other hand, the echoes are the correction to the late stage of the quasinormal ringing for a black hole, which is caused by the deviation of the spacetime relative to the initial black hole spacetime geometry in the near-horizon region. In this work, we study the gravitational wave echoes of black bounces spacetime surrounded by a cloud of strings under scalar field and electromagnetic field perturbation to explore what gravitational effects near-horizon region are caused by string cloud. The ringing of the regular black hole and traversable wormhole with string cloud are presented. Our results demonstrate that the black bounce spacetime with strings cloud is characterized by gravitational wave echoes as it transitions from regular black holes to wormholes, i.e. the echoes signal will facilitate us to distinguish between black holes and the wormholes in black bounces surrounded by the string cloud

Learning to Select for MIMO Radar based on Hybrid Analog-Digital Beamforming

In this paper, we propose an energy-efficient radar beampattern design framework for a Millimeter Wave (mmWave) massive multi-input multi-output (mMIMO) system, equipped with a hybrid analog-digital (HAD) beamforming structure. Aiming to reduce the power consumption and hardware cost of the mMIMO system, we employ a machine learning approach to synthesize the probing beampattern based on a small number of RF chains and antennas. By leveraging a combination of softmax neural networks, the proposed solution is able to achieve a desirable beampattern with high accuracy

Probing hairy black holes caused by gravitational decoupling using quasinormal modes, and greybody bounds

Extended gravitational decoupling can add hair to the black holes in general relativity by adding extra sources. The quasinormal modes of hairy black holes caused by gravitational decoupling for the massless scalar field, electromagnetic field, and axial gravitational perturbation are investigated. The equation of effective potential for three perturbations is derived in hairy black holes spacetime. We also study the time evolution corresponding to the three perturbations, and the quasinormal mode frequencies are calculated using the Prony method through the time-domain profiles. Particularly, we find that the response of hairy black hole spacetime to axial gravitational perturbations is completely different from scalar field and electromagnetic field perturbations, which may be due to the fact that the gravitational radiation produced by the perturbations of the hairy black hole metric itself is much stronger than that of the external field. Furthermore, we have calculated the bounds on this greybody factor and high-energy absorption cross section with the Sinc approximation. The study reveals that the charges ($\alpha$ and $l_0$) generating primary hair contributes positively to the greybody bounds and absorption cross section, whereas the tidal charge $Q$ from the extra sources does the opposite

Voltage and frequency droop control of a microgrid in islanded modes

Nowadays, there are increased amount of distributed generation and renewable resources (including geothermal, ocean tides, solar and wind) used in the microgrid systems, which are connected via the power inverters. Microgrid is a concept that the systems include at least one distributed generation resources and local loads can switch to islanded power distributed systems, [1]. Duo to the small scale of microgrid, the voltage and frequency of system will carry more severe fluctuations then the larger grids, which will be able to stable these fluctuations via the wider systems, [9]. The inverters can provide the stability and redundancy to the power systems. For the normally working of the high current electronic devices, it is deviation that several inverters operate in parallel in the systems, [3]. The inverter control methods which should be able to bring the reliable and efficient electricity to microgrid system have attracted much attention in recent years. Various droop control methods are regarded as the effective solving technique in conventional generation system. The droop control strategy is associated with using local power to detect the load changes of complex powers in the system and adjusting the outputs, automatically, [2]. The advantage of droop control method is to allow the distributed generators in the system can operate without external mechanism communications, [3]. No mechanical communication means the system can adjust and share the loads among distributed generators (connected via inverters) automatically when the loads change happen. This is based on the calculation of droop control characteristics. The droop control uses the real power to adjust the frequency of loads, and vary the reactive power to vary the voltage of loads. However, droop control scheme are different when the impact of complex impedance is considered. The experimental simulation results will be presented to illustrate how the droop control scheme impacts the power distributions of parallel-connected inverters