We review the results on the characteristic polynomial, spectrum, spectral radius and energy of the distance matrix of graphs.

The performance of a Turbo code depends on the interleaver design. There are two major criteria that can be considered in the design of an interleaver. Distance spectrum properties of the code and the correlation of the extrinsic information with the input data are the two major criteria in designing an interleaver. This paper describes a new interleaver design based on these two criteria. Simu...

The ultrasonic transmission through plates perforated with 2 × 2 or 3 × 3 square array of subwavelength holes per unit cell are studied by numerical simulations. Calculations are obtained by means of a theoretical model under the rigid-solid assumption. It is demonstrated that when the inter-hole distance within the unit cell is reduced, new transmission dips appear resulting from Wood anomalie...

We observed in §2.1 that if the propagation distance z is small, then the propagation problem may be accurately and efficiently solved in the Fourier domain. This is not a new observation—see, e.g., [16, 14]—so our objective here is simply to demonstrate how this propagation method (the so-called angular spectrum method) can be implemented using the quadratures from Theorem 2 to ensure any user...

Many spectrum methods have been proposed to use spectrum effectively, the opportunistic spectrum access has become the most viable approach to achieve near-optimal spectrum utilization by allowing secondary users to sense and access available spectrum opportunistically. However, a naive spectrum access for secondary users can make spectrum utilization inefficient and increase interference to ad...

When can one see from the spectrum of a graph whether it is distance-regular or not? We give some new results for when this is the case. As a consequence we find (among others) that the following distance-regular graphs are uniquely determined by their spectrum: The collinearity graphs of the generalized octagons of order (2, 1), (3, 1) and (4, 1), the Biggs-Smith graph, the M22 graph, and the ...

A tomographic imaging system based on wavelength-scanning digital interference holography is developed by applying the angular spectrum method. Compared to the well-known Fresnel diffraction formula, which is subject to a minimum distance requirement in reconstruction, the angular spectrum method can reconstruct the wave field at any distance from the hologram plane. The new system allows three...

This article introduces chirp spread spectrum technology (CSS for short) and optimized location algorithm. Symmetric double-sided two way ranging technique (SDS– TWR for short) is applied to improve accuracy and range of measurement. Linear frequency modulation ranging technology utilizes protocols combining CSMA / CA and TDMA, and adjusts dynamically transmission rate and frame length accordin...

Spectrum sensing has been put forward to make more efficient use of scarce radio frequency spectrum. The leading eigenvector of the sample covariance matrix has been applied to spectrum sensing under the frameworks of PCA and kernel PCA. In this paper, spectrum sensing with subspace matching is proposed. The subspace is comprised of the eigenvectors corresponding to dominant non-zero eigenvalue...