scholarly journals An Improved Product Code-Based Data Hiding Scheme

2018 ◽  
Vol 8 (11) ◽  
pp. 2119
Author(s):  
Wen-Rong Zhang ◽  
Yuh-Ming Huang
Keyword(s):  
Data Hiding ◽  
The Other ◽  
Two Dimensional ◽  
Optimal Solutions ◽  
Approximation Approach ◽  
One Dimensional ◽  
Product Code ◽  
Embedding Efficiency ◽  
Matrix Embedding ◽  
Embedding Rate

This paper explores the data hiding schemes which are based on the principle of matrix embedding. Under the same embedding rate, the efficiency of each data hiding scheme is evaluated by the metric of average embedding efficiency. In the literature, both the row-column embedding and the weight approximation embedding algorithms are sub-optimal solutions for the product code-based data hiding problem. For the former, it is still based on the concept of one-dimensional (1-D) toggle syndrome, and the concept of two-dimensional (2-D) toggle syndrome is directly adopted for the latter one. Data hiding with multiple embedding channels is the practice of hiding messages into hidden media many times. Here, two multi-channel embedding-based data hiding techniques—one is the 1-D toggle syndrome-based embedding scheme (1DTS-1), and the other is the improved weight approximation-based embedding scheme (2DTS-1), are presented. In the former, the proposed one-off decision technique is used to determine the locations of the required modification bits, and the amount of modification will be reduced through utilizing the characteristics of the linear code. With the technique of the former, in the latter, the amount of modification bits can be further reduced because that a toggle array with better structure is generated, which is more suitable for being assigned as the initial toggle array while applying the weight approximation approach. The experimental results show our proposed hybrid 1-D/2-D toggle syndrome-based embedding scheme (2DTS-1) has increased the embedding efficiency by 0.1149 when compared to the weight approximation embedding algorithm. Further, the embedding efficiency of the latter one can be further and significantly enhanced through the Hamming+1 technique.

scholarly journals The influence of resistivity gradients on shock conditions for a Petschek reconnection geometry

2016 ◽  
Vol 34 (4) ◽  
pp. 421-425
Author(s):  
Christian Nabert ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Magnetic Field ◽  
Necessary Conditions ◽  
The Other ◽  
Diffusion Region ◽  
Two Dimensional ◽  
Characteristic Velocity ◽  
Magnetohydrodynamic Equations ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Alfven Velocity

Abstract. Shock waves can strongly influence magnetic reconnection as seen by the slow shocks attached to the diffusion region in Petschek reconnection. We derive necessary conditions for such shocks in a nonuniform resistive magnetohydrodynamic plasma and discuss them with respect to the slow shocks in Petschek reconnection. Expressions for the spatial variation of the velocity and the magnetic field are derived by rearranging terms of the resistive magnetohydrodynamic equations without solving them. These expressions contain removable singularities if the flow velocity of the plasma equals a certain characteristic velocity depending on the other flow quantities. Such a singularity can be related to the strong spatial variations across a shock. In contrast to the analysis of Rankine–Hugoniot relations, the investigation of these singularities allows us to take the finite resistivity into account. Starting from considering perpendicular shocks in a simplified one-dimensional geometry to introduce the approach, shock conditions for a more general two-dimensional situation are derived. Then the latter relations are limited to an incompressible plasma to consider the subcritical slow shocks of Petschek reconnection. A gradient of the resistivity significantly modifies the characteristic velocity of wave propagation. The corresponding relations show that a gradient of the resistivity can lower the characteristic Alfvén velocity to an effective Alfvén velocity. This can strongly impact the conditions for shocks in a Petschek reconnection geometry.

scholarly journals A stronger recognizability condition for two-dimensional languages

2013 ◽  
Vol Vol. 15 no. 2 (Automata, Logic and Semantics) ◽  
Author(s):  
Marcella Anselmo ◽  
Maria Madonia
Keyword(s):  
Finite Automata ◽  
The Other ◽  
Two Dimensional ◽  
Minimal Size ◽  
One Dimensional ◽  
Tiling System ◽  
International Audience ◽  
The One

Automata, Logic and Semantics International audience The paper presents a condition necessarily satisfied by (tiling system) recognizable two-dimensional languages. The new recognizability condition is compared with all the other ones known in the literature (namely three conditions), once they are put in a uniform setting: they are stated as bounds on the growth of some complexity functions defined for two-dimensional languages. The gaps between such functions are analyzed and examples are shown that asymptotically separate them. Finally the new recognizability condition results to be the strongest one, while the remaining ones are its particular cases. The problem of deciding whether a two-dimensional language is recognizable is here related to the one of estimating the minimal size of finite automata recognizing a sequence of (one-dimensional) string languages.

Two-dimensional partial orderings: Undecidability

1980 ◽  
Vol 45 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Alfred B. Manaster ◽  
Joseph G. Rosenstein
Keyword(s):  
Bipartite Graph ◽  
Bipartite Graphs ◽  
The Other ◽  
Two Dimensional ◽  
One Dimensional ◽  
Recursive Model ◽  
Linear Orderings ◽  
Other Hand ◽  
Partial Orderings ◽  
Planar Lattices

In this paper we examine the class of two-dimensional partial orderings from the perspective of undecidability. We shall see that from this perspective the class of 2dpo's is more similar to the class of all partial orderings than to its one-dimensional subclass, the class of all linear orderings. More specifically, we shall describe an argument which lends itself to proofs of the following four results:(A) the theory of 2dpo's is undecidable:(B) the theory of 2dpo's is recursively inseparable from the set of sentences refutable in some finite 2dpo;(C) there is a sentence which is true in some 2dpo but which has no recursive model;(D) the theory of planar lattices is undecidable.It is known that the theory of linear orderings is decidable (Lauchli and Leonard [4]). On the other hand, the theories of partial orderings and lattices were shown to be undecidable by Tarski [14], and that each of these theories is recursively inseparable from its finitely refutable statements was shown by Taitslin [13]. Thus, the complexity of the theories of partial orderings and lattices is, by (A), (B) and (D), already reflected in the 2dpo's and planar lattices.As pointed out by J. Schmerl, bipartite graphs can be coded into 2dpo's, so that (A) and (B) could also be obtained by applying a Rabin-Scott style argument [9] to Rogers' result [11] that the theory of bipartite graphs is undecidable and to Lavrov's result [5] that the theory of bipartite graphs is recursively inseparable from the set of sentences refutable in some finite bipartite graph. (However, (C) and (D) do not seem to follow from this type of argument.)

scholarly journals Two-scale mathematics and fractional calculus for thermodynamics

2019 ◽  
Vol 23 (4) ◽  
pp. 2131-2133 ◽  
Author(s):  
Ji-Huan He ◽  
Fei-Yu Ji
Keyword(s):  
Fractional Calculus ◽  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Dimensional Problem ◽  
Dimensional Approach ◽  
One Dimensional ◽  
Fractal Calculus ◽  
Lower Dimensional ◽  
The Continuum

A three dimensional problem can be approximated by either a two-dimensional or one-dimensional case, but some information will be lost. To reveal the lost information due to the lower dimensional approach, two-scale mathematics is needed. Generally one scale is established by usage where traditional calculus works, and the other scale is for revealing the lost information where the continuum assumption might be forbidden, and fractional calculus or fractal calculus has to be used. The two-scale transform can approximately convert the fractional calculus into its traditional partner, making the two-scale thermodynamics much promising.

scholarly journals First-Principles Study of Structure and Magnetism in Copper(II)-Containing Hybrid Perovskites

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1129
Author(s):  
João N. Gonçalves ◽  
Anthony E. Phillips ◽  
Wei Li ◽  
Alessandro Stroppa
Keyword(s):  
First Principles ◽  
The Other ◽  
High Symmetry ◽  
Two Dimensional ◽  
Imidazolium Cation ◽  
One Dimensional ◽  
First Principles Study ◽  
Antiferromagnetic Ordering ◽  
Jahn Teller ◽  
Jahn Teller Effect

We report a first-principles study of hybrid organic–inorganic perovskites with formula [A]Cu(H2POO)3 (A = triazolium (Trz) and guanidinium (Gua), and H2POO− = hypophosphite), and [HIm]Cu(HCO2)3 (HIm = imidazolium cation, HCO2− = formate). The triazolium hypophosphite and the formate have been suggested as possible ferroelectrics. We study the fully relaxed structures with different magnetic orderings and possible phonon instabilities. For the [Trz]Cu hypophosphite, the Trz cation is shown to induce large octahedral distortions due to the Jahn-Teller effect, with Cu-O long-bond ordering along two perpendicular directions, which is correlated with antiferromagnetic ordering and strongly one-dimensional. We find that the structure is dynamically stable with respect to zone-center distortions, but instabilities appear along high symmetry lines in the Brillouin zone. On the other hand, for the [HIm]Cu formate, large octahedral distortions are found, with large Cu-O bonds present in half of the octahedra, in this case along a single direction, and correspondingly, the magnetism is almost two-dimensional.

scholarly journals The spectrum of MHD flows about X points

1998 ◽  
Vol 60 (2) ◽  
pp. 421-446
Author(s):  
R. J. NIJBOER ◽  
J. P. GOEDBLOED ◽  
A. E. LIFSCHITZ
Keyword(s):  
Mach Number ◽  
Physical Space ◽  
The Other ◽  
Two Dimensional ◽  
Fourier Space ◽  
Dimensional Problem ◽  
Essential Spectra ◽  
Plasma Flows ◽  
One Dimensional ◽  
Magnetohydrodynamic Flows

A recently proposed method to calculate the spectrum of linear, incompressible, unbounded plasma flows is applied to magnetohydrodynamic flows about X points. The method transforms the two-dimensional spectral problem in physical space into a one-dimensional problem in Fourier space. The latter problem is far easier to solve. Application of this method to X-point plasma flows results in two kinds of essential spectra. One kind corresponds to stable perturbations and the other one to perturbations that become overstable whenever the square of the poloidal Alfvén Mach number becomes larger than 1. Apart from these two spectra, no other spectral values were found.

scholarly journals Crystal structure of anhydrous poly[bis(μ2-sarcosinato-κ3O,N:O′)copper(II)]

2014 ◽  
Vol 70 (10) ◽  
pp. 207-209
Author(s):  
Ray J. Butcher ◽  
Greg Brewer ◽  
Matthew Zemba
Keyword(s):  
The Other ◽  
Coordination Geometry ◽  
Two Dimensional ◽  
Hydrogen Bonding Interaction ◽  
Asymmetric Unit ◽  
One Dimensional ◽  
Intermolecular Hydrogen Bonding Interaction ◽  
Bonding Interaction ◽  
Jahn Teller ◽  
Adjacent Molecule

The title compound, [Cu(C3H6NO2)2]n, is a bis-complex of the anion of sarcosine (N-methylglycine). The asymmetric unit consists of a copper(II) ion, located on a center of inversion, and one molecule of the uninegative sarcosinate anion. The copper(II) ion exhibits a typical Jahn–Teller distorted [4 + 2] coordination geometry. The four shorter equatorial bonds are to the nitrogen and carboxylate O atoms of two sarcosinate anions, and the longer axial bonds are to carboxylate O atoms of neighboring complexes. The overall structure is made up from two chains formed by these longer axial Cu—O bonds, one extending parallel to [011] and the other parallel to [0-11]. Each one-dimensional array is connected by the equatorial bridging moieties to the chains on either side, creating an extended two-dimensional framework parallel to (100). There is a single intermolecular hydrogen-bonding interaction within the sheets between the amino NH group and an O atom of an adjacent molecule.

scholarly journals Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

2016 ◽  
Vol 7 ◽  
pp. 1983-1990 ◽  
Author(s):  
Carlos J Páez ◽  
Dario A Bahamon ◽  
Ana L C Pereira ◽  
Peter A Schulz
Keyword(s):  
Transmission Spectrum ◽  
Quantum Confinement ◽  
The Other ◽  
Two Dimensional ◽  
Atomic Chain ◽  
One Dimensional ◽  
Atomic Crystal

We theoretically investigate phosphorene zigzag nanoribbons as a platform for constriction engineering. In the presence of a constriction at one of the edges, quantum confinement of edge-protected states reveals conductance peaks, if the edge is uncoupled from the other edge. If the constriction is narrow enough to promote coupling between edges, it gives rise to Fano-like resonances as well as antiresonances in the transmission spectrum. These effects are shown to mimic an atomic chain like behavior in a two dimensional atomic crystal.

A movable pair of tetrahedra

1989 ◽  
Vol 423 (1865) ◽  
pp. 419-442 ◽  
Keyword(s):  
Degrees Of Freedom ◽  
The Other ◽  
Two Dimensional ◽  
Smooth Manifolds ◽  
One Dimensional ◽  
Bifurcation Phenomenon

When we draw all the diagonals of all the faces of a cube, we obtain the edges of two regular tetrahedra. Keeping one of these fixed, we move the other under the condition that the originally intersecting edges of the two tetrahedra should still remain coplanar (i. e. intersect, are parallel or coincide). We determine all such finite motions. These will be seen to constitute one-dimensional and two-dimensional smooth manifolds. We also deal with the infinitesimal degrees of freedom of the motions of our mechanism. In several positions the number of infinitesimal degrees of freedom is not one or two, but is three; this is connected with the bifurcation phenomenon of the solutions.

scholarly journals Pattern of neutral polymorphism in a geographically structured population

1971 ◽  
Vol 18 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Motoo Kimura ◽  
Takeo Maruyama
Keyword(s):  
Finite Size ◽  
The Other ◽  
Two Dimensional ◽  
Gene Frequencies ◽  
High Tendency ◽  
One Dimensional ◽  
Structured Population ◽  
Local Differentiation ◽  
Stepping Stone Model ◽  
Entire Distribution

SUMMARYIn a two-dimensional stepping-stone model of finite size, if a pair of alleles happen to segregate in the whole population, marked local differentiation of gene frequencies can occur only if migration between colonies is sufficiently rare so that Nm < 1, where N is the effective size of each colony and m is the rate at which each colony exchanges individuals with four surrounding colonies each generation. On the other hand, if Nm ≥ 4, the whole population behaves as if it were panmictic and the allelic frequencies become uniform over the entire distribution range unless mutation is unusually high. Tendency toward local differentiation is much weaker in two-dimensional than in one-dimensional habitats.

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