In Session 15, the reason why many quanta have spin 1/2 was demonstrated by applying circuit theory to the Dirac equation. In this session, we attempt to apply circuit theory to the Dirac equation from a different viewpoint and determine a model in which electrons and neutrinos are not bound to other quanta and exist independently. We also determine a model of neutrons and protons that have spin 1/2 and can be bound to other quanta and show that this model represents the elements of an asymmetric LC ladder circuit, which can be treated as particles.
Feature extraction is crucial for underwater target classification and recognition, and this paper aims to propose a scheme for accurately classifying the material features of underwater targets. Finite element simulation software COMSOL is used to obtain echo signals, and then Auto Regressive (AR) coefficient, cepstrum feature, spectral peak and its frequency of Smoothing Pseudo Wigner-Ville Distribution (SPWVD) of echo signals are extracted as the input of the pattern recognition network. The classification results show that the proposed scheme is able to effectively differentiate among four types of materials: metal, brick, plastic and rubber. The scheme also shows good robustness for the target size and shape, and the proposed scheme has the potential to be applied to the practical underwater target classification.
One dimensional (1D) spectral amplitude coding-optical code division multiple access (SAC-OCDMA) systems are generally known by a strict limitation in the number of users that can simultaneously connect. A main solution to overcome this drawback consists of constructing a two-dimensional (2D) structure using a new hybrid spectral/spatial code through combining a one dimensional new zero cross correlation code (NZCC) to a one dimenional multi-diagonal code (1D MD) to easily provide null cross-correlation properties and totally remove the multiple access interferences. Accordingly, this research paper describes an easy and fast technique to construct a hybrid two-dimensional NZCC-MD code based on a non diagonal matrix for SAC-OCDMA systems with direct spectral/spatial dimension (SDD) detection technique and water-filling (WF) optimization. The novel code presents many advantages such as less complex structure, acceptable code length as well as the possibility to construct it for any weight value. The proposed code demonstrates a very good performance for systems with high debit and high simultaneous user number keeps a less complex structure.
Line spectrum detection is a significant task to detect, track, and classify weak target sources for passive sonar systems. In order to solve the problem of tracking time-varying frequency trajectories, a track-before-detect (TBD) algorithm based on the two-layer particle filter structure is proposed. The detect layer deals with the potential tracks by maintaining a low-threshold dynamic detection grid, which is used to determine the birth, death, and false alarm of targets. The tracking layer utilizes the particle filter to compute the joint multitarget probability density through a Bayesian framework. Simulation results show that the proposed algorithm can effectively detect and track time-varying frequency trajectories in a low signal-to-noise ratio situation, which has certain research and application value in weak signal detection.
