Determination of the method of construction of 1650 B.C. wall paintings

In this paper, a methodology of general applicability is presented for answering the question if an artist used a number of archetypes to draw a painting or if he drew it freehand. In fact, the contour line parts of the drawn objects that potentially correspond to archetypes are initially spotted. Subsequently, the exact form of these archetypes and their appearance throughout the painting is determined. The method has been applied to celebrated Thera Late Bronze Age wall paintings with full success. It has been demonstrated that the artist or group of artists has used seven geometrical archetypes and seven corresponding well-constructed stencils (four hyperbolae, two ellipses, and one Archimedes' spiral) to draw the wall painting "Gathering of Crocus" in 1650 B.C. This method of drawing seems to be unique in the history of arts and of great importance for archaeology, and the history of mathematics and sciences, as well.     

Image and Pattern Analysis of 1650 B.C. Wall Paintings and Reconstruction

In this paper, a color image segmentation method and a pattern analysis are presented, in connection with the extraordinary 1650 B.C. wall paintings found in the Greek island of Thera. These wall paintings are usually reconstructed from thousands of fragments widely scattered in the excavated site. The fragments' depiction manifests inhomogeneous color decay, cracks, added extraneous material, etc. The proposed color image segmentation method takes into account the decay problems and offers a very good approximation of the initial fragment depiction as the artist drew it in the late Bronze Age. The algorithm performs essentially better than other standard segmentation schemes as extensive qualitative tests indicate. Moreover, it offers clear-cut color regions and region borders for each fragment depiction. The whole approach is based on classifying the pixels into a number of regions where each region is described by a normal distribution, followed by fragment-decay reduction and edge refining. Extensive pattern analysis to the obtained region borders leads to the conclusion that 3650 years ago, the artist most probably used advanced geometrical methods in order to construct handcrafted ldquoFrench curvesrdquo (stencils or templates) and use them to draw certain figures. On the basis of the aforementioned results, specific pattern matching techniques are employed for the reconstruction of wall paintings, depicting spirals, from their constituent fragments.     

A survey of architectures and scenarios in satellite‐based wireless sensor networks: system design aspects

This paper is not a survey related to generic wireless sensor networks (WSNs), which have been largely treated in a number of survey papers addressing more focused issues; rather, it specifically addresses architectural aspects related to WSNs in some way connected with a satellite link, a topic that presents challenging interworking aspects. The main objective is to provide an overview of the potential role of a satellite segment in future WSNs. In this perspective, requirements of the most meaningful WSN applications have been drawn and matched to characteristics of various satellite/space systems in order to identify suitable integrated configurations. Copyright © 2012 John Wiley & Sons, Ltd.     

Coexistence of the broadcasting satellite service with fixed service systems in frequency bands above 10 GHz

The allocation of certain frequency bands to both the broadcasting satellite service and the fixed service on a primary basis raises the issue of coexistence, whenever the two types of services are located in the same area and no coordination/agreement is effected. Although regulatory institutions have issued general guidelines concerning future systems, the effect of frequency sharing by numerous operating satellite earth terminals should be examined. The present paper provides an analytical methodology for the prediction of the carrier-to-noise plus interference ratio (CNIR) of broadcasting satellite systems, suffering from interference from an adjacent terrestrial link at frequencies above 10 GHz. The proposed model takes into account the aggravation of intersystem interference due to the spatial inhomogeneity of precipitation. A simplified version of the analytical model, useful for back of the envelope computations is also presented. Some interesting case studies are finally examined.     

Ice crystals and raindrop canting angle effects applied to satellite interference prediction with respect to heavy rain climatic zones

For frequencies above 10GHz the performance of the operating satellite systems is mainly aggravated because of the potential existing severe rain attenuation. As a result of the above fading mechanism, the dominant interference sources encountered in this frequency band are the following: differential rain attenuation induced by an adjacent satellite system operating in the same frequency, and cross talk between orthogonally polarized signals. The latter source concerns of course satellite systems employing the dual polarization mode. In the present paper, an already existing method to predict interference statistics, due to above reasons, is properly modified to include ice crystals and raindrop canting angle effects. The assumption that the point rainfall rate statistics follows a gamma form, valid for heavy rain climatic regions such as J, M, N, P, Q zones, is also adopted. The sensitivity of various parameters affecting the interference performance, after introducing the novel assumptions, is finally investigated.     

On the automated recognition of seriously distorted musicalrecordings

A new methodology is presented for the automated recognition-identification of musical recordings that have suffered from a high degree of playing speed and frequency band distortion. The procedure of recognition is essentially based on the comparison between an unknown musical recording and a set of model ones, according to some predefined specific characteristics of the signals. In order to extract these characteristics from a musical recording, novel feature extraction algorithms are employed. This procedure is applied to the whole set of model musical recordings, thus creating a model characteristic database. Each time we want an unknown musical recording to be identified, the same procedure is applied to it, and subsequently, the derived characteristics are compared with the database contents via an introduced set of criteria. The proposed methodology led to the development of a system whose performance was extensively tested with various types of broadcasted musical recordings. The system performed successful recognition for the 94% of the tested recordings. It should be noted that the presented system is parallelizable and can operate in real time     

Local Structural Distortions and Phase Separation in Cuprates

We report evidence from Raman measurements of local lattice distortions in the cuprates, which are induced at room temperature by varying the hydrostatic pressure and correlate with changes in the superconducting transition temperature. Anomalous nonlinear pressure dependence is observed for almost all A_g phonons of the YBa₂Cu₃O_6.5, YBa₂Cu₃O_over, and YBa₂Cu₄O₈ superconducting single crystals, which occurs at pressures where the transition temperature shows also characteristic changes. The results are compared with a similar correlation found between transition temperature and spectral modifications in Bi₂Sr₂CaCu₂O₈ by pressure and in YBa₂Cu₃O_x and La_2–xSr_xCuO₄ by chemical doping. There are strong indications that the saturation of T_c with pressure or compositional doping in these cuprates is mainly related with lattice instabilities and probably also with phase separation phenomena.     

Characteristic sequence motifs at the breakpoints of the hybrid genes FUS/CHOP, EWS/CHOP and FUS/ERG in myxoid liposarcoma and acute myeloid leukemia

We have sequenced the breakpoint regions in one acute myeloid leukemia (AML) with t(16;21)(p11;q22) resulting in the formation of a FUS/ERG hybrid gene and in four myxoid liposarcomas (MLS), three of which had the translocation t(12;16) (q13;p11) and a FUS/CHOP fusion gene and one with t(12;22;20)(q13;q12;q11) and an EWS/CHOP hybrid gene. The breakpoints were localized to intron 7 of FUS, intron 1 of CHOP, an intronic sequence of ERG and intron 7 of EWS. In two MLS cases with t(12;16) and in the AML, the breaks in intron 7 of FUS had occurred close to each other, a few nucleotides downstream from a TG dinucleotide repeat region. The break in the two MLS had occurred in the same ATGGTG hexamer and in the AML 40 nucleotides upstream from the hexamer. The third case of t(12;16) MLS had a break upstream and near a TC-dinucleotide repeat region and a sequence similar to the chi bacterial recombination element was found to flank the breakpoint. In the MLS with the EWS/ CHOP hybrid gene, the break in intron 7 of EWS had occurred close to an Alu sequence. Similarly, in all 4 MLS, the breaks in intron 1 of CHOP were near an Alu sequence. No Alu or other repetitive sequences were found 250 bp upstream or downstream from the break in the ERG intron involved in the AML case. In the AML, the MLS with ESW/CHOP and in one MLS with FUS/CHOP there were one, two and six, respectively, nucleotide identity between the contributing germline sequences in the breakpoint. In the other two MLS cases, two and three extra nucleotides of unknown origin were inserted between the FUS and CHOP sequences. At the junction and/or in its close vicinity, identical oligomers, frequently containing a trinucleotide TGG, were found in both partner genes. Our data thus show that all four genes-FUS, EWS, CHOP and ERG-contain characteristic motifs in the breakpoint regions which may serve as specific recognition sites for DNA-binding proteins and have functional importance in the recombination events taking place between the chromosomes. Different sequence motifs may, however, play a role in each individual case.     

Laser surface treatment of copper

Copper specimens were irradiated with a KrF excimer laser. The surface morphology and structure of laser-treated copper was examined using optical and electron microscopy. Using X-ray diffraction, the residual stress on the copper surface layers was found to change from tensile to compressive as a result of laser treatment. The surface roughness of the copper was observed to be a function of laser power density. The corrosion resistance of the laser-treated copper was also studied in an NaCl solution.     

Small-target detection in sea clutter

Sea clutter in marine surveillance radar makes the task of detecting small targets a very challenging problem. In this paper, a set of three signal processing techniques designed to suppress unwanted sea clutter radar echo and achieve target detection with no prior knowledge of the ocean and environmental conditions is presented. These include signal averaging, time-frequency representation, and morphological filtering. Datasets from real marine radar operating in staring mode are used to illustrate the performance of the new approaches.