An image watermarking based on the pdf modeling and quantization effects in the wavelet domain

An image watermarking technique based on the concept of JPEG2000 algorithm is proposed. Biorthogonal wavelet 9/7 transform is used to provide a set of coefficients suitable for watermark embedding. The statistical properties of different subbands are analyzed in order to choose the number of decomposition levels and position of subbands, which will assure the best compromise between the watermark transparency and robustness. The JPEG2000 quantization is applied to avoid insignificant wavelet coefficients, while the remaining ones are used for watermarking. The optimal and blind watermark detection is based on the nonlinear score function and appropriate model of coefficients distribution. The performance of the proposed procedure is tested on examples with various images, showing robustness under different attacks, while maintaining high image quality.     

meSAT: multiple encodings of CSP to SAT

One approach for solving Constraint Satisfaction Problems (CSP) (and related Constraint Optimization Problems (COP)) involving integer and Boolean variables is reduction to propositional satisfiability problem (SAT). A number of encodings (e.g., direct, log, support, order) for this purpose exist as well as specific encodings for some constraints that are often encountered (e.g., cardinality constraints, global constraints). However, there is no single encoding that performs well on all classes of problems and there is a need for a system that supports multiple encodings. We present a system that translates specifications of finite linear CSP problems into SAT instances using several well-known encodings, and their combinations. We also present a methodology for selecting a suitable encoding based on simple syntactic features of the input CSP instance. Thorough evaluation has been performed on large publicly available corpora and our encoding selection method improves upon the efficiency of existing encodings and state-of-the-art tools used in comparison.     

A new set distance and its application to shape registration

We propose a new distance measure, called Complement weighted sum of minimal distances, between finite sets in ${\mathbb Z }^n$ and evaluate its usefulness for shape registration and matching. In this set distance the contribution of each point of each set is weighted according to its distance to the complement of the set. In this way, outliers and noise contribute less to the new similarity measure. We evaluate the performance of the new set distance for registration of shapes in binary images and compare it to a number of often used set distances found in the literature. The most extensive evaluation uses a set of synthetic 2D images. We also show three examples of real problems: registering a set of 2D images extracted from synchrotron radiation micro-computed tomography (SR $\upmu $ CT) volumes depicting bone implants; the difficult multi-modal registration task of finding the exact location of a 2D slice of a bone implant, as imaged by a light microscope, within a 3D SR $\upmu $ CT volume of the same implant; and finally recognition of handwritten characters. The evaluation shows that our new set distance performs well for all tasks and outperforms the other observed distance measures in most cases. It is therefore useful in many image registration and shape comparison tasks.     

Quantum correlations at negative absolute temperatures

We study behavior of quantum discord, a kind of quantum correlation, in systems of dipole–dipole interacting spins in an external magnetic field in the whole temperature range ( \(-\infty ). It was shown that negative temperatures, which are introduced to describe inversions in the population in a finite level system, provide more favorable conditions for emergence of quantum correlations including entanglement. We show that at negative temperature, the correlations become more intense and discord exists between remote spins being in separated states.     

Raman Spectroscopy of Nanocrystalline Ceria and Zirconia Thin Films

The results of Raman-scattering studies of nanocrystalline CeO₂ and ZrO₂:16% Y (YSZ) thin films are presented. The relationship between the lattice disorder and the form of the Raman spectra is discussed and correlated with the microstructure. It is shown that the Raman line shape results from phonon confinement and spatial correlation effects and yields information about the material nonstoichiometry level.     

Thermoplastic extrusion—the mechanism of the formation of extrudate structure and properties

Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water-plasticized biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow. The mixed-melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder die from a viscous state to a rubber-like state and then to a glassy state caused by cooling and drying. Incompatibility of proteins and polysaccharides in their water-plasticized melt mixtures impacts on structure formation and texturization during thermoplastic extrusion. Presented at the 20th ISF World Congress and 83rd AOCS Annual Meeting and Expo, May 10–14, 1992, Toronto, Ontario, Canada.     

Self-diffusion of low-generation PAMAM dendrimers with hydroxyl surface groups in solutions: a general regularity

An experimental study of the self-diffusion and nuclear magnetic relaxation of poly(amidoamine) dendrimers with hydroxyl surface groups (PAMAM-OH) dissolved in methanol over a wide range of concentration (?) is reported. It is shown that experimental concentration dependences of PAMAM-OH self-diffusion coefficients (D) can be reduced to the so-called generalized ? dependence. Over macromolecular concentration range studied, the generalized concentration dependence of PAMAM-OH D coincides with analogous curve obtained for poly(allylcarbosilane) dendrimers of high generations. This result confirms the existence of common regularities of the dendritic macromolecule self-diffusion, and their independence of the individual physicochemical and structural properties of dendrimer, solvent, and features of their interactions in the given systems. The concentration dependence of the PAMAM-OH diffusion also exhibits a clear signature of an inflexible molecule.     

Structures and electronic properties of surface/edges of nanodiamond and nanographite

The structure, electronic and magnetic properties of nanodiamond and nanographite/nanographene are investigated. Detonation nanodiamond particles that are covered with amorphous graphitic composites are hydrothermally treated to remove the graphitic surface composites and to terminate the surface carbon atoms with hydrogen. The number of localized spins of dangling bonds and the hydrogen concentration increase upon the increase in the hydrothermal treatment time up to 40 h. Above 40 h, both drop discontinuously, a surface structural reconstruction was suggested. The creation of dangling bonds and an incomplete hydrogenation of the surface carbon atoms destabilize the surface, resulting in the structural reconstruction. Nanodiamond particles are thermally converted to nanographite/nanographene. A single nanographene sheet is successfully prepared by heat-treating nanodiamond particles. The edge of graphene sheet with its edge carbon atoms being hydrogen-terminated is investigated by UHV-STM/STS. Zigzag edges are found to have non-bonding π-state of edge origin, in good agreement with theoretical prediction.     

Aluminium electrodeposition from AlCl3-NaCl melts on glassy carbon,platinum and gold electrodes

The electrochemical deposition and dissolution of aluminium on glassy carbon, platinum and gold electrodes in chloraluminate melts have been investigated using linear sweep voltammetry and potentiostatic pulse techniques. It was shown that deposition of aluminium on the glassy carbon electrode at low overpotentials takes place by 3-D progressive nucleation and growth, with the incorporation of atoms in the crystal lattice as the rate-determining step. At overpotentials higher than –100 mV vs Al, in the melts containing more than 52 mol % of AlCl₃, diffusion of Al₂Cl ₇ ^– , takes over the control of deposition of aluminium. Alloying of platinum and gold electrodes with aluminium from the melt occurs in the underpotential region.