We introduce a new P system model called as parallel contextual array insertion deletion P system, based on the modified row and column contextual rules of parallel contextual array grammar. We can generate a family o...
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ISBN:
(纸本)9783319591087;9783319591070
We introduce a new P system model called as parallel contextual array insertion deletion P system, based on the modified row and column contextual rules of parallel contextual array grammar. We can generate a family of two-dimensional picture languages using this P system. We discuss some properties of this P system and find its generating power by comparing this new family of languages with that of certain other well known families of two-dimensional picture languages.
Siromoney et al. introduced Siromoney matrix grammars (1973) which are of sequential-parallel type in the sense that first a horizontal string of nonterminals is derived sequentially by applying the horizontal product...
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ISBN:
(纸本)9783030510015;9783030510022
Siromoney et al. introduced Siromoney matrix grammars (1973) which are of sequential-parallel type in the sense that first a horizontal string of nonterminals is derived sequentially by applying the horizontal production rules and then vertical productions are applied in parallel to get the intended two-dimensional picture. In 1999, Radhakrishnan et al. introduced and studied a variant of Siromoney matrix grammars called (X:Y)MG where X, Y is an element of {Context - Free(CF), Regular(R)}. James et al. in 2018 introduced Parallel Contextual array Insertion Deletion Grammar (PCAIDG) to generate two-dimensional array languages using insertion and deletion operations and parallel contextual mappings. In this paper, we prove that this family of languages generated by PCAIDGs properly includes the family (CF : CF) ML.
We introduce a new grammar, called parallel contextual array insertion deletion grammar and show that it has a strictly higher generative power than a system generating recognizable 2D-picture language and Siromoney c...
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ISBN:
(纸本)9783030052881;9783030052874
We introduce a new grammar, called parallel contextual array insertion deletion grammar and show that it has a strictly higher generative power than a system generating recognizable 2D-picture language and Siromoney context-sensitive matrix grammar.
We introduce new P system models, called as external and internal parallel contextual array P systems, based on the external and internal parallel contextual array grammars. We can generate rectangular arrays using th...
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The problem of 2-D angle estimation for coprime multiple-input multiple-output (MIMO) radar is considered, and a low-complexity propagator based method is proposed. Coprime MIMO radar is configured with transmit and r...
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The problem of 2-D angle estimation for coprime multiple-input multiple-output (MIMO) radar is considered, and a low-complexity propagator based method is proposed. Coprime MIMO radar is configured with transmit and receive rectangular arrays, where transmit array has NxQ elements while receive array has MxP elements (M is coprime to N while P is coprime to Q). Based on the uniformities of the arrays, unitary transformation is exploited to transform the complex data into real-valued one, and then the signal subspace is obtained from a low-complexity propagator matrix, which requires neither eigenvalue decomposition nor pseudo inversion. Thereafter, automatically paired two pairs of coprime parameter estimations can be acquired based on the rotational invariance within the signal subspace. Finally, unique 2-D angle can be estimated from the coincide result of the coprime estimations. Due to the real-valued propagator based method, the proposed method has low complexity, but it can achieve better angle estimation results than conventional methods. Theoretical analysis of the method is derived, and simulation results are presented to verify the effectiveness of the proposed approach.
Two-dimensional numerical simulations were conducted for the natural convection phenomena in a cold square enclosure containing four hot circular cylinders with Rayleigh number in the range of 10(3) <= Ra <= 10(...
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Two-dimensional numerical simulations were conducted for the natural convection phenomena in a cold square enclosure containing four hot circular cylinders with Rayleigh number in the range of 10(3) <= Ra <= 10(6) and a Prandtl number of Pr = 0.7. The immersed boundary method (IBM) was used to capture the virtual wall boundary of the cylinders based on the finite volume method (FVM). In the present study, the variation in the vertical position of the cylinders was compared with those in the diagonal and horizontal positions. The change in the flow and thermal structures and corresponding heat transfer characteristics were investigated in regard to the transition of the flow regime from the steady state to the unsteady state at a relatively high Rayleigh number. In addition, the effects of the cylinder positions of a rectangular array in the square enclosure on the heat transfer characteristics are highlighted. (C) 2017 Elsevier Ltd. All rights reserved.
This paper addresses a two-dimensional (2-D) direction of arrival (DOA) estimation of coherent signals problem. To do so, we first reconstruct a covariance-like matrix, and then apply forward and backward spatial smoo...
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This paper addresses a two-dimensional (2-D) direction of arrival (DOA) estimation of coherent signals problem. To do so, we first reconstruct a covariance-like matrix, and then apply forward and backward spatial smoothing (FBSS) method as a preprocessor to remedy the rank deficiency problem. By utilizing the covariance-like matrix instead of outputs sensors in the FBSS method, the noise and small fading factor influences are reduced in the DOA estimation problem. Afterward, two matrix pencil pairs are exploited to extract 2-D DOA of impinging signals. This two matrix pencil pairs method can estimate 2-D DOA with repeated eigenvalues efficiently and also pair the estimated parameters automatically. The proposed algorithm not only has all the privileges of the estimation of signal parameters via rotational invariant techniques (ESPRIT)-like algorithm but also increases the array aperture. By mathematical tractability, we derive Cramer-Rao bounds for azimuth and elevation angles for coherent signals received by uniform rectangular array to compare the performance of the estimation algorithms with a lower bound. Simulation results show that the proposed algorithm outperforms the symmetric configuration of uniform rectangular array (SC-URA), the FBSS-multiple-signal classification (FBSS-MUSIC) and the ESPRIT-like algorithms in terms of root mean squared error (RMSE).
This study conducted two-dimensional numerical simulations of the natural convection phenomena in a cold square enclosure containing four hot elliptical cylinders with a rectangular array. Rayleigh numbers in the rang...
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This study conducted two-dimensional numerical simulations of the natural convection phenomena in a cold square enclosure containing four hot elliptical cylinders with a rectangular array. Rayleigh numbers in the range of 10(4) <= Ra <= 10(6) and a Prandtl number of Pr = 0.7 were considered. The immersed boundary method (IBM) was used to capture the virtual wall boundary of the cylinders based on the finite volume method (FVM). The main parameters investigated include the Rayleigh number and aspect ratio of the cylinders. The aspect ratio of the cylinders was varied in the range of 0.25 <= AR <= 4.00. The flow and thermal structures and corresponding heat transfer characteristics were investigated with respect to the transition of the flow regime from steady state to unsteady state. As a result, ((Nu(CYL)) over bar) increased by about 4.38% and ((Nu(EN)) over bar) increased by about 5.24% at AR = 4.00 with increasing AR compared to AR = 1.00 (Circular cylinder). Thus, the variation in AR has a remarkable influence on the heat transfer characteristics at the cylinder surfaces and the walls of the enclosure. (C) 2018 Elsevier Ltd. All rights reserved.
In the paper we propose the semianalytic method to estimate the dependence of the sweep efficiency on well spacing for the well pattern of horizontal wells with multiple hydraulic fractures. The method is based on the...
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In the paper we propose the semianalytic method to estimate the dependence of the sweep efficiency on well spacing for the well pattern of horizontal wells with multiple hydraulic fractures. The method is based on the assumption that the sand body size distribution is the lognormal distribution. Parameters of this distribution are obtained through the analysis of statistical data on sand body sizes for the particular depositional environment of the oil field.
Technique to find direction of arrival (DOA) has been promisingly constructed by, smart antenna technology. It consists of array antennas and signal processing unit. Because of the limitation of space in commercial pr...
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Technique to find direction of arrival (DOA) has been promisingly constructed by, smart antenna technology. It consists of array antennas and signal processing unit. Because of the limitation of space in commercial products, the size of antenna array should be designed with the smallest dimension. Also the processing unit is expected in low complexity and expense. Most of DOA finders were recently proposed employing linear array in which the Size is linearly increased as a number of antenna elements. Also the processing units were fully comprised with high level of computation. In this paper, the low profile of 2.4 GHz DOA finder is proposed. The DOA finder is designed in the compact Size of 2 x 2 array antennas. Using modified Butler matrix, the processing unit is very, simple in which it can be handled by any economic microprocessors. The proposed finder is able to delicately specify DOA in every angle from 0 degrees to 360 degrees. The experimental results confirm the success of proposed DOA finder. (C) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 252-256 2009: Published online in Wiley InterScience (***). DOI 10.1002/mop.23984
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