Search

An improved circulating current control method by applying a digital plug-in repetitive controller is discussed for harmonic elimination of a carrier-phase-shift pulse-width-modulation (CPS-PWM)-based modular multilevel converter (MMC) in this paper. The performance of the controller is analyzed in detail based on an improved circulating current control model with the consideration of the submodule voltage disturbance. It is shown that the proposed control method has the merits of simplicity, versatility, and better performance of circulating harmonic current elimination than the traditional proportional integral controller. The stability analysis of the proposed method are also discussed in the paper as well as the design principles. Finally, the experimental results including the steady-state performance and the transient response are given, which validates the feasibility and excellent performance of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The extensive use of pulse width modulation control technology in smart grid will lead to prominent enlargement of high-frequency harmonics. The effects of the distributed capacitances of transmission line and transformer that are neglected previously will be very obvious. The performance of the traditional harmonic eliminating method for wideband harmonic is limited, which will lead to huge challenge to the analysis, evaluation, and elimination of harmonics as well as series and parallel resonance problem. In this paper, to accurately describe the influence of wideband harmonic on smart grid, the multiterminal analysis model of harmonic degradation in smart grid is established, especially the distributed capacitances of the transmission line and the transformer are considered. Then, a novel topology of hybrid active power filter (HAPF) for resonance damping and multitype harmonic eliminating is proposed. The resonance damping model of the new topology is established; analysis results indicate that the proposed HAPF has a good harmonic resonance damping characteristic. Both simulation and experimental results have validated the validity of the theoretical analysis in this paper. [ABSTRACT FROM AUTHOR]

This paper proposes a robust and accurate method for measuring 3-D surfaces using a binocular system. To eliminate the effect caused by the distortion of projector lens, each structured light sheet is fitted to a conicoid. A curvilinear detector, which combines the zero-crossing detection algorithm with Steger's detector, is employed to detect the sub pixel locations of the light stripes, thus preventing the Steger's curvilinear detector from failing to detect them in the end points of the stripes. The proposed coding method combines the information of the linked line with the gray code to avoid producing outliers caused by erroneous decoding and make the coding procedure more robust. Experiments showed that each structured light sheet fitted to a conicoid can effectively improve the measurement accuracy. The subpixel detection method can detect the exact sub pixel locations of the stripes. Likewise, the encoding strategy results in the production of fewer outliers, while the reconstruction result becomes more perfect. [ABSTRACT FROM AUTHOR]

In this paper we present a low complexity decoding algorithm for Raptor codes which is used for incremental redundancy hybrid ARQ schemes. Encoding and decoding Raptor codes are the processes of making encoding symbols from the source symbols and the recovery of the source symbols from the received encoding symbols transmitted through an erasure channel, respectively. If the received encoding symbols are insufficient to recover the source symbols, additional encoding symbols are delivered and decoded with the previously received encoding symbols. We propose a low complexity decoding algorithm which efficiently combines the previously received encoding symbols and incremental encoding symbols. The proposed algorithm has excellent potential for realizing low power operation and higher throughput transmission due to its highly reduced computational complexity. [ABSTRACT FROM AUTHOR]

Selective harmonic elimination/control has been a widely researched alternative to traditional pulse-width modulation techniques. Previous and current work has made fundamental assumptions that enforce output waveform quarter-wave symmetry, presumably in order to reduce the complexity of the resulting equations. However, the quarter-wave symmetric assumption is not strictly necessary. It restricts the solution space, which can result in sub-optimal solutions with regards to the uncontrolled harmonic distribution. A more general formulation is proposed, removing the quarter-wave symmetry constraint for two classes of the m-level, n-harmonic harmonic control problem. The special cases of two- and three-level harmonic elimination are presented in detail along with representative solutions for each harmonic control problem. New solutions previously unattainable based on quarter-wave symmetric techniques are identified. [ABSTRACT FROM AUTHOR]

Given the number of checking points, the speed of block motion estimation depends on how fast the block matching is. In this paper, a new framework, fine granularity successive elimination (FGSE), is proposed for fast optimal block matching in motion estimation. The FGSE features providing a sequence of nondecreasing fine-grained boundary levels to reject a checking point using as little computation as possible, where block complexity is utilized to determine the order of partitioning larger sub- blocks into smaller subblocks in the creation of the fine-grained boundary levels. It is shown that the well-known successive elimination algorithm (SEA) and multilevel successive elimination algorithm (MSEA) are just two special cases in the FGSE framework. Moreover, in view that two adjacent checking points (blocks) share most of the block pixels with just one pixel shifting horizontally or vertically, we develop a scheme to predict the rejection level for a candidate by exploiting the correlation of matching errors between two adjacent checking points. The resulting predictive FGSE algorithm can further reduce computation load by skipping some redundant boundary levels. Experimental results are presented to verify substantial computational savings of the proposed algorithm in comparison with the SEAIMSEA. [ABSTRACT FROM AUTHOR]

In this correspondence, we present a technique for generation of linear subcodes of a given turbo code with better distance spectrum than the original mother turbo code, via an iterative process of trace-bit injection which minimally reduces code rate, followed by selective puncturing that allows recovery of the rate toss incurred during the trace-bit injection. The technique allows for asymptotic performance improvement of any linear turbo code. In effect, we trim the distance spectrum of a turbo code via elimination of the low distance and/or high multiplicity codewords from the output space of the code. To this end, we perform a greedy minimization of a cost function closely related to the asymptotic bit error probability (or frame error probability) of the code. This improves the performance of the code everywhere, but its main impact is a reduction in the error floor of the turbo code which is important for delay constrained applications employing short interleavers. [ABSTRACT FROM AUTHOR]

Sequential forward selection (SFS) and sequential backward elimination (SBE) are two commonly used search methods in feature subset selection. In the present study, we derive an orthogonal forward selection (OFS) and an orthogonal backward elimination (OBE) algorithms for feature subset selection by incorporating Gram-Schmidt and Givens orthogonal transforms into forward selection and backward elimination procedures, respectively. The basic idea of the orthogonal feature subset selection algorithms is to find an orthogonal space in which to express features and to perform feature subset selection. After selection, the physically meaningless features in the orthogonal space are linked back to the same number of input variables in the original measurement space. The strength of employing orthogonal transforms is that features are decorrelated in the orthogonal space, hence individual features can be evaluated and selected independently. The effectiveness of our algorithms to deal with real world problems is finally demonstrated. [ABSTRACT FROM AUTHOR]

Part I. Presents information on a study which determined the average errors capacity region of an arbitrarily varying multiple-access channel (AVMAC) using elimination technique. Description of a decoding rule for AVMAC; Deviational properties.