Information and Meaning

Since the publication of Claude Shannon’s groundbreaking paper, “A Mathematical Theory of Communication,” in two parts in the Bell Laboratory journal in 1948, understanding and research concerning communication and information has received a technicized treatment. As biosemiotics has been at the forefront in arguing, all living organisms communicate, but they do not do so in the digital mode used in information technology (IT) engineering. Life communicates in inherited, evolutionary ways that are traceable from single cells all the way to complex humans. What IT engineers call “redundancy” those studying living organisms call “meaning.” The trade between individual organisms and their environment takes place in the circulation, interpretation, and feedback loops of semiosis. In this way, organisms are able to maintain the features of adaptive, creative, and evolutionary learning systems by modeling their worlds in open, receptive fashion via the use of iconic and indexical signs. In other words, organisms make use of natural, then cultural metaphors and metonyms.

Efficient Detectors based on Group Detection for Massive MIMO systems

In Multiple Input Multiple Output (MIMO) systems, the complexities of detectors depend on the size of the channel matrix. In Massive MIMO systems, detection complexity becomes remarkably higher because the dimensions of the channel matrix get much larger. In order to recover the signals in the up-link of a Massive MIMO system at reduced complexities, we first divide the system into two sub-systems. After that, we apply the Minimum Mean Square Error (MMSE) and Bell Laboratory Layer Space Time (BLAST) detectors to each subsystem, resulting in the so-called MMSE-GD and BLAST-GD detectors, respectively. To further enhance the BER performance of Massive MIMO systems under the high-load conditions, we propose two additional detectors, called MMSE-IGD and BLAST-IGD by respectively applying the conventional MMSE and BLAST on the sub-systems in an iterative manner. It is shown via computer simulation and analytical results that the proposed detectors enable the system to achieve not only higher BER performance but also low detection complexities as compared to the conventional linear detectors. Moreover, the MMSE-IGD and BLAST-IGD can significantly improve BER performance of Massive MIMO systems.

Full-Wave Analysis of Field-to-Line Coupling Effects Using 1D FDTD Method under Exciting Source with Different Bandwidths

With the aim to analyze field-to-line coupling effects based on energy spectrum, parallel finite-difference time-domain (FDTD) method is applied to calculate the induced voltage on overhead lines under high-power electromagnetic (HPEM) environment. Firstly, the energy distribution laws of HEMP (IEC 61000-2-9), HEMP (Bell Laboratory), HEMP (Paulino et al., 2010), and LEMP (IEC61000-4-5) are given. Due to the air-earth stratified medium, both the absorbing boundary and the connecting boundary applied to scattering by finite-length objects are separately set in aerial and underground parts. Moreover, the influence of line length on induced voltage is analyzed and discussed. The results indicate that the half-peak width is wider with the increase of the line length. But the steepness of induced voltage on the overhead line is invariable. There is no further increase in the peak of induced voltage especially when the line length increases to be equivalent to the wavelength of the frequency bands with the maximum energy.