Spin Wave Normalization Towards all Magnonic Circuits

The key enabling factor for Spin Wave (SW) technology utilization for building ultra low power circuits is the ability to energy efficiently cascade SW basic computation blocks. SW Majority gates, which constitute a universal gate set for this paradigm, operating on phase encoded data are not input output coherent in terms of SW amplitude, and as such, their cascading requires information representation conversion from SW to voltage and back, which is by no means energy effective. In this paper, a novel conversion free SW gate cascading scheme is proposed that achieves SW amplitude normalization by means of a directional coupler. After introducing the normalization concept, we utilize it in the implementation of three simple circuits and, to demonstrate its bigger scale potential, of a 2-bit inputs SW multiplier. The proposed structures are validated by means of the Object Oriented Micromagnetic Framework (OOMMF) and GPU-accelerated Micromagnetics (MuMax3). Furthermore, we assess the normalization induced energy overhead and demonstrate that the proposed approach consumes 20% to 33% less energy when compared with the transducers based conventional counterpart. Finally, we introduce a normalization based SW 2-bit inputs multiplier design and compare it with functionally equivalent SW transducer based and 16nm CMOS designs. Our evaluation indicate that the proposed approach provided 26% and 6.25x energy reductions when compared with the conventional approach and 16nm CMOS counterpart, respectively, which demonstrates that our proposal is energy effective and opens the road towards the full utilization of the SW paradigm potential and the development of SW only circuits.

Spin Wave Normalization Towards all Magnonic Circuits

The key enabling factor for Spin Wave (SW) technology utilization for building ultra low power circuits is the ability to energy efficiently cascade SW basic computation blocks. SW Majority gates, which constitute a universal gate set for this paradigm, operating on phase encoded data are not input output coherent in terms of SW amplitude, and as such, their cascading requires information representation conversion from SW to voltage and back, which is by no means energy effective. In this paper, a novel conversion free SW gate cascading scheme is proposed that achieves SW amplitude normalization by means of a directional coupler. After introducing the normalization concept, we utilize it in the implementation of three simple circuits and, to demonstrate its bigger scale potential, of a 2-bit inputs SW multiplier. The proposed structures are validated by means of the Object Oriented Micromagnetic Framework (OOMMF) and GPU-accelerated Micromagnetics (MuMax3). Furthermore, we assess the normalization induced energy overhead and demonstrate that the proposed approach consumes 20% to 33% less energy when compared with the transducers based conventional counterpart. Finally, we introduce a normalization based SW 2-bit inputs multiplier design and compare it with functionally equivalent SW transducer based and 16nm CMOS designs. Our evaluation indicate that the proposed approach provided 26% and 6.25x energy reductions when compared with the conventional approach and 16nm CMOS counterpart, respectively, which demonstrates that our proposal is energy effective and opens the road towards the full utilization of the SW paradigm potential and the development of SW only circuits.

Intra-Pulse Modulation Classification of Radar Emitter Signals Based on a 1-D Selective Kernel Convolutional Neural Network

The intra-pulse modulation of radar emitter signals is a key feature for analyzing radar systems. Traditional methods which require a tremendous amount of prior knowledge are insufficient to accurately classify the intra-pulse modulations. Recently, deep learning-based methods, especially convolutional neural networks (CNN), have been used in classification of intra-pulse modulation of radar emitter signals. However, those two-dimensional CNN-based methods, which require dimensional transformation of the original sampled signals in the stage of data preprocessing, are resource-consuming and poorly feasible. In order to solve these problems, we proposed a one-dimensional selective kernel convolutional neural network (1-D SKCNN) to accurately classify the intra-pulse modulation of radar emitter signals. Compared with other previous methods described in the literature, the data preprocessing of the proposed method merely includes zero-padding, fast Fourier transformation (FFT) and amplitude normalization, which is much faster and easier to achieve. The experimental results indicate that the proposed method has the advantages of faster speed in data preprocessing and higher accuracy in intra-pulse modulation classification of radar emitter signals.

Efficient Feature Set Developed for Acoustic Gunshot Detection in Open Space

This paper presents an efficient approach to automatic gunshot detection based on a combination of two feature sets: adapted standard sound features and hand-crafted novel features. The standard features are mel-frequency cepstral coefficients adapted for gunshot recognition in terms of uniform gamma-tone filters linearly spaced over the whole frequency range from 0 kHz to 16 kHz. The first 18 coefficients calculated from the 41 filters represent the best set of the optimized cepstral coefficients. The novel features were derived in the time domain from individual significant points of the raw waveform after amplitude normalization. Experiments were performed using single and ensemble neural networks to verify the effectiveness of the novel features for supplementing the standard features. The novelty of the work is the proposed feature combination, which allows to achieve very effective detection of gunshots from hunting weapons using 23 features and a simple neural network. In binary classification, the developed approach achieved an accuracy of 95.02 % in gunshot detection and 98.16 % in disregarding other sounds (i.e., non-gunshot).