Domain Block Research Articles

An FFT-based technique for fast fractal image compression

We present a new FFT-based technique of fractal image compression which can significantly speed up the process of matching domain and range blocks. In this method the isometric transformations of a domain block are chosen to permit block matching through cross correlation of range and domain blocks, which is implemented through the FFT. A suboptimal choice of domain blocks by performing a magnitude Fourier domain comparison of the range and domain blocks prior to correlation further speeds up the block matching process.

Fractal block coding in residue domain

A new block-based fractal image coding algorithm called Fractal Block Coding in Residue Domain (FBCRD) is proposed. In basic Fractal Block Coding (FBC) algorithm, each block (called range block) is encoded by an affine mapping from a domain block within the same image to itself. The decoder uses the parameters of these mappings to synthesize the reconstructed image through an iterative procedure. FBCRD is a modification of basic FBC. In FBCRD, range blocks and domain blocks are all residue blocks subtracted from their block means and both the parameters of affine mappings and block means are coded. This modification leads to fewer iterations at the decoder. An optimized decoding strategy is also introduced which reduces total decoding time by more than half of that of basic FBC. This improvement is favorable for real time implementation of fractal image compression.

Fractal Coding of Video Sequence by Circular Prediction Mapping

We propose a novel algorithm for fractal video sequence coding, based on the Circular Prediction Mapping (CPM), in which each range block is approximated by a domain block in the circularly previous frame. In our approach, the size of the domain block is set to be same as that of the range block for exploiting the high temporal correlation between the adjacent frames, while most other fractal coders use the domain block larger than the range block. Therefore the domain-range mapping in the CPM becomes similar to the block matching algorithm in the motion compensation techniques, and the advantages from this similarity are discussed. Also the modified collage theorem, which yields better prediction method for the CPM than the conventional collage theorem, is provided by linear systematic analysis. The computer simulation results on real video-conferencing image sequences demonstrate that the average compression ratios ranging from 60 to 70 can be obtained with good subjective quality.

Orthonormal Fractal Image Encoding Using Overlapping Blocks

This paper presents a novel approach to partitioned fractal image encoding. In this we seek to address a number of problems with earlier fractal encodings. These are: the artefacts associated with the block based approaches at high compression ratios; accuracy limitations imposed by the constraint that only one domain block is used to construct each range block; convergence problems which have required that constraints be imposed on the scaling coefficients to ensure that the mapping functions are contractive. These problems are addressed with a technique based on an orthonormal basis expansion using overlapping blocks, where the basis is partly fixed and partly derived from the image in such a way as to take advantage of local interscale self similarity. A fractal image codec based on this technique, which we call the Lapped Orthogonal Fractal Transform (LOFT), is described and tested, and the results are compared to those of other codecs.

Codebook Clustering by Self-Organizing Maps for Fractal Image Compression

A fast encoding scheme for fractal image compression is presented. The method uses a clustering algorithm based on Kohonen's self-organizing maps. Domain blocks are clustered, yielding a classification with a notion of distance which is not given in traditional classification schemes.

Orogenesis and dynamics of the Qinling Orogen

The Qinling is a composite orogen which experienced three different developmental stages under distinct tectonic regimes. The main stage (Neo-Proterozoic- Middle Triassic) of the erogenic evolution is a prolonged and complicated process, and characterized by subduction and collision along two suture zones between three plates. The details of the orogenic processes, such as transition from rift system to plate-tectonic regime, from drifting to subduction and collision, and especially from point-contact initial collision through linear-contact collision to fully collisional orogeny, demonstrate that the Qinling was built up by dispersion, integration and accretion of a number of crustal blocks in Tethyan domain, and evolved under the influence of variation in coupling relationship between both ancient and modern mantle dynamics and lithosphere.

On the performance of fractal compression with clustering

The paper investigates a technique to reduce the computational complexity of fractal image compression on gray-scale images. The technique uses a clustering process on image domain blocks with the clusters formed with the use of k-d trees and the fast pairwise nearest neighbor algorithm of Equitz (1984). Results indicate the method is effective for smaller domain block sizes and generally shows improvement in terms of picture peak signal-to-noise ratio (SNR) over the quadrant variance classification method.

Xklp2, a Novel Xenopus Centrosomal Kinesin-like Protein Required for Centrosome Separation during Mitosis

We describe a novel Xenopus plus end–directed kinesin-like protein (KLP), Xklp2, localized on centrosomes throughout the cell cycle and on spindle pole microtubules during metaphase. Using mitotic spindles assembled in Xenopus egg extracts and different recombinant GST–Xklp2 mutants, we show that this motor is targeted to spindle poles through its C-terminal domain. Xklp2-truncated polypeptides lacking the motor domain block centrosome separation and disrupt preassembled metaphase spindles. Antibodies directed against the tail of Xklp2 have a similar effect. These results show that Xklp2 protein is required for centrosome separation and maintenance of spindle bipolarity. This study is an example of the application of the dominant negative mutant effect on spindle assembly in Xenopus egg extracts, demonstrating the usefulness of this approach in probing the function of proteins in this system.

Analysis and efficient implementation of partitioned block LMS adaptive filters

The frequency domain block LMS (FBLMS) algorithm used for efficient implementation of adaptive filters whose length may exceed a few thousands of taps is explored further by Asharif et al. (1980). To reduce the latency of such filters, it has been proposed that the adaptive filter convolution sum be partitioned into a few smaller sums and then the FBLMS be applied. We show that the scheme proposed by Asharif et al. suffers from a serious eigenvalue spread problem. We identify the source of this problem and propose a solution to that.

Formula omitted] and [formula omitted] geochronologic studies of the eastern Borborema Province, Northeastern Brazil: initial conclusions

The Borborema Province of NE Brasil comprises the central part of a wide Pan-African-Brasiliano orogenetic belt that formed as a consequence of late Neoproterozoic convergence and collision of the São Luis-West Africa craton and the São Francisco-Congo-Kasai cratons. New Sm Nd and U Pb results from the eastern part of this province help to define the basic internal architecture and pre-collisional history of this province, with particular emphasis on delineating older cratonic terranes, their fragmentation during the Mesoproterozoic, and their assembly into West Gondwana during the Pan African-Brasiliano orogeny at ca. 600 Ma. The region can be divided into three major geotectonic domains: a) Rio Piranhas-Caldas Brandão massif, with overlying Paleoproterozoic to Neoproterozoic supracrustal rocks, north of the Patos Lineament; b) the Archean to Paleoproterozoic São Francisco craton (SFC) to the south; and c) a complex domain of Paleoproterozoic to Archean basement blocks with several intervening Mesoproterozoic to Neoproterozoic fold belts in the center (south of Patos Lineament and north of SFC). The northern and central domains comprise the Borborema Province. Archean basement gneiss and Transamazonian granulite of northern SFC are exposed in the southern part of the central domain, underlying southern parts of the Sergipano fold belt. Basement in the Rio Piranhas massif appears to consist mostly of Transamazonian (2.1 to 2.2 Ga) gneissic rocks; Nd model ages (T DM) of ca. 2.6 Ga for 2.15 Ga gneisses indicate a substantial Archean component in the protoliths to these gneisses. The Caldas Brandão massif to the east yields both Transamazonian and Archean U Pb zircon and Nd (T DM) ages, indicating a complex architecture. Metasedimentary rocks of the Jucurutu Formation yield detrital zircons with original crystallization ages as young as 1.8 Ga, indicating that these rocks may be late Paleoproterozoic and correlate with other ca. 1.8 Ga cratonic supracrustal rocks in Brazil such as the Roraima Group and Espinhaço Group. Most metavolcanic and pre-Brasiliano granitic units of the Sergipano (SDS), Pajeú-Paraíba (SPP), Riacho Pontal (SRP), and Piancó-Alto Brígida (SPAB) fold belts in the central domain formed ~ 1.0 ± 0.1 Ga, based on U Pb ages of zircons. Nd model ages (T DM) for these same rocks, as well as Brasiliano granites intruded into them and large parts of the Pernambuco-Alagoas massif, are commonly 1.3–1.7 Ga, indicating that rocks of the fold belts were not wholly derived from either older (> 2.1 Ga) or juvenile (ca. 1.0 Ga) crust, but include mixtures of both components. A simple interpretation of Brasiliano granite genesis and the Nd data implies that there is no Transamazonian or Archean basement underlying large parts of these fold belts or of the Pernambuco-Alagoas massif. An exception is a belt of syenitic Brasiliano plutons (Syenitoid Line) and host gneisses between SPAB and SPP that clearly has a Transamazonian (or older) source. In addition, there are several smaller blocks of Archean to Transamazonian gneiss that can be defined within and among these fold belts. These blocks do not appear to constitute a continuous basement complex, but appear to be isolated older crustal fragments. Our data support a model in which ca. 1.0 Ga rifting was an important tectonic and crust-forming event along the northern edge of the São Francisco craton. Our data also show that significant parts of the Borborema Province are not remobilized Transamazonian to Archean crust, but that Mesoproterozoic crust is a major feature of the Province. There are several small remnants of older crust within the area dominated by Mesoproterozoic crust, suggesting that the rifting event created several small continental fragments that were later incorporated into the Brasiliano collisional orogen. We cannot at present determine if the Rio Piranhas-Caldas Brandão massifs and the older crustal blocks of the central domain were originally part of the São Francisco craton or whether some (or all) of them came from more exotic parts of the Proterozoic Earth. Finally, our data have not yet revealed any juvenile terranes of either Transamazonian or Brasiliano age.

Enhancing the speed of fractal image compression

Fractal coding of digital images offers many promising qualities. The coding process, however, suffers from the long search time of the domain block pool. We obtain mathematical results on the distance measure used in the search. Then we derive an incremental procedure to bound the domain block pixels. We arrange the domain blocks in a tree structure and utilize the procedure to direct the search. We show that this method speeds up the coding process by up to 50 times, without noticeable loss of image quality. Our procedure works in conjunction with other methods such as block classification

Fast image domain fractal compression by DCT domain block matching

Fractal image compression entails a computationally costly search for matching image blocks. It is proposed that a block be represented by its DCT coefficients, which may be made invariant to many of the usual block transforms. Owing to the energy packing properties of the DCT, the efficiency of an existing multidimensional nearest neighbour search is improved.

Stratigraphic and structural synthesis of a Miocene extensional terrane, southeast California and west-central Arizona

Detailed stratigraphy and isotopic dating of stratigraphic sections in the Colorado River extensional corridor support a regional correlation of highly faulted Tertiary stratigraphic sequences and provide a chronologic framework for interpreting the evolution of low-angle normal (detachment) faults. On the basis of this correlation, we define six tilting domains in the upper plate of the Whipple, Chemehuevi, and Rawhide detachment faults and identify three discrete episodes of detachment faulting that began in the early Miocene and ended in middle Miocene time. Episodes of rapid detachment faulting are indicated by extreme tilting of upper-plate fault blocks and overlying Miocene sequences, fanning dips of basinal deposits, and angular unconformities that represent short time gaps in the accumulation of syntectonic sequences. During the first episode of detachment faulting at about 20 Ma, the upper plate segmented to form the domains. Basin subsidence and extreme tilting of upper-plate fault blocks and syntectonic deposits characterized the eastern Topock, Crossman, Aubrey, Parker Dam, and Buckskin-Rawhide domains, whereas the western Mopah domain was the site of abundant volcanic activity but no basins or tilting. A second episode of extension at about 18 Ma produced extreme tilts in the Buckskin-Rawhide domain but upper-plate blocks in the Mopah domain tilted moderately. A third regionwide faulting episode between 14 and 12 Ma was due to localized uplift of middle and lower crust and eventual exposure of the detachment faults and their footwalls. The upper-plate fault blocks responded passively to localized slip on the detachment faults. Rapid extension began on the Whipple-Chemehuevi detachment fault at 20 Ma and had shifted southward to the Buckskin-Rawhide detachment fault by 18 Ma; volcanic activity also shifted southward to the Buckskin-Rawhide domain at this time. The southward shift of rapid extension and volcanism probably represents buildup and release of strain at localized sites in the lower plate. Otherwise, stratigraphic and structural relations indicate that the locations of upper-plate basins, faulting and tilting of upper-plate blocks, and position of the breakaway zone remained stable throughout the major phases of extension.

Generalized sliding FFT and its application to implementation of block LMS adaptive filters

This paper has two contributions. First, the concept of the generalized sliding fast Fourier transform (GSFFT) as an efficient implementation of the hopping FFT is introduced. Application of the GSFFT is broad and not limited to what has been considered in this paper. The frequency domain block LMS (FBLMS) adaptive filters are then revised, and their implementations for block lengths less than the length of the adaptive filter are studied. The GSFFT and the available pruned FFTs are used to give an efficient implementation of these filters. In the particular case of the block length equal to one, where the FBLMS algorithm reduces to the frequency domain LMS (FLMS) algorithm, it is shown that the latter can be implemented with the order of M complexity, where M is the length of the adaptive filter. >

Anti-tumor activity of a blocked ricin immunotoxin with specificity against the cluster-5A antigen associated with human small-cell lung cancer.

The monoclonal antibody (MAb SEN31, a mouse IgG1 which recognizes the cluster-5a antigen on small-cell lung cancer (SCLC) cells, was used to prepare a selective and potent blocked ricin immunotoxin. In a series of experiments in vitro and in a SCLC xenograft model in nude mice, the tumor localization potential of the radiolabeled antibody SEN31 and the anti-tumor activity of the immunotoxin SEN31-bR, the non-specific binding activity of which had been greatly reduced by blocking of the galactose binding domains of the B-chain, was determined. Radiolabeling of SEN31 was performed by linking a 67Ga-labeled desferrioxamine moiety to the oligosaccharide side chains of the antibody in order to preserve the specific cell-binding activity. 67Ga-SEN31 bound to the antigenic sites on cells of the SW2 SCLC cell line, with a dissociation constant of 3.5 nM and, when injected i.v., selectively localized at the site of s.c.-growing SW2 tumor xenografts in nude mice, with a tumor-to-blood ratio of 3.5. The immunotoxin SEN31-bR was potently and selectively active against SCLC cell lines both of classic and of variant morphologies. At a concentration of 300 pM the immunotoxin selectively eliminated 4.5 logs of clonogenic tumor cells. In nude mice, SEN31-bR was cleared from the blood with biphasic kinetics following i.v. injection and maintained a stable serum level during continuous i.p. infusion. The growth of s.c. SW2 solid-tumor xenografts was delayed following a single i.v. injection or a continuous i.p. infusion, each at a non-toxic dose.

Upscaling of permeability of anisotropic heterogeneous formations: 1. The general framework

In numerical simulations of flow through heterogeneous formations, the domain is partitioned into numerical elements. The solution requires assigning physical properties to each numerical block. The process of transferring information from the scale of actual heterogeneity to that of the numerical elements is known as upscaling. We consider steady, one‐phase flow and the only property of interest is the permeability, which is regarded as a random space function, and the same is true for the upscaled conductivity. In this paper we establish the necessary and sufficient conditions to be satisfied by upscaling. The necessary conditions are expressed with the aid of the global response of the formation, e.g., the total flux caused by a constant pressure head drop applied on the boundaries. The requirement is that the expected value and the variance of the total flux are the same in the actual and upscaled domains. These are supplemented by local conditions which stipulate that space averages of flow variables over the numerical blocks in the upscaled domain tend to those in the actual formation when the elements size tends to 0. The result of this analysis is that the upscaled permeability must be such as to ensure the equality, in a statistical sense, between the space averaged dissipation in the two media. By assuming an unbounded domain, average uniform flow and stationarity, simplified relationships between the moments of the dissipation in the upscaled and actual media are derived. It is shown that the effective permeability of the two media is the same. The approach is illustrated for stratified formations for which exact composition rules are possible. Even in this simple case the upscaled permeability is a tensor, characterized at second order by two mean components and three covariance functions.

Multi‐rate numerical methods for diffusion problems

AbstractThe one‐dimensional diffusion equation is solved using a recent class of multi‐rate numerical algorithms collectively referred to as waveform relaxation methods. The methods enable different parts or blocks in the system to take widely different time steps by decoupling the blocks in the time domain. Significant speed‐up is obtained over the results using a composite trapezoidal rule/second‐order backward Euler time‐stepping scheme without blocking. Possible implementation strategies for two‐dimensional diffusion are briefly discussed.

Fractal-based image sequence compression scheme

The dominant image transformation used in the existing fractal coding schemes is the affine function. Although an affine transformation is easy to compute and understand, its linear approximation ability limits the employment of larger range blocks, that is, it limits further improvement in compression efficiency. We generalize the image transformation from the usual affine form to the more general form, e.g., quadratic form, and provide theoretical requirements for the generalized transformation to be contractive. Based on the self-transformation system (STS) model, an image sequence coding scheme-fractal-based image sequence coding-is proposed. In this coding scheme, our generalized transformation is used to model the self-transformation from the domain block to its range blocks. Experimental results on a real image sequence show that for the same size of blocks, the SNR can be improved by 10 dB, or, for the same SNR of the decoded image sequence, the compression ratio is raised twofold when the new generalized transformation is used to replace the usual affine transformation. In addition, due to the utilization of the STS model, the computational complexity is only linearly related to the size of the 3-D blocks. This provides for fast encoding and decoding.

Auto-Waves in Liquid Crystals. I. Nonstationary Electrohydrodynamic Instability

Abstract It has been found that the coherent domain oscillations which perform stochastic auto-oscillations appear in nematic liquid crystals above the threshold of electrohydrodynamic instability in de-electric field. In this case the oscillating domain block generates the nonlinear orientational waves. The voltage dependences of the wave length, velocity of propagation and period of wave process have been measured.

Arc deformation and marginal basin opening: Japan Sea as a case study

We discuss the opening mechanism of the Japan Sea in Miocene time using (1) tectonic and published paleomagnetic data along the eastern margin from the north of Hokkaido Island to Sado Island, (2) a mechanical model which is tested by small‐scale physical modeling, and (3) crustal structure and bathymetric features in the Japan Sea which constrain our kinematic model and preopening reconstructions. Our main conclusions are the following. The eastern margin of the Japan Sea was, as a whole, a dextral shear zone about 100 km wide. This conclusion is supported by the existence of a ductile dextral shear zone in Central Hokkaido (Hidaka Mountains) and associated brittle deformation in western Hokkaido and northeastern Honshu. The stress field during the opening (which ended about 12 Ma ago at the end of the middle Miocene) changes from right‐lateral transpression in the north to right‐lateral transtension in the south. The western margin, along the Korean peninsula, during the same period, also was an active dextral shear zone. Paleomagnetic results indicate that clockwise rotations occurred in the south during the opening and counterclockwise rotations in the north. We propose a model of right‐lateral pull‐apart deformation with clockwise rotations of rigid blocks in the southern transtensional domain and counterclockwise rotations in the transpressional one. Small‐scale physical models show that the clockwise rotation in transtension is possible provided that the eastern boundary (Pacific side) is free of stress. The opening stopped and compression subsequently began about 12 Ma ago. Finally, we show that the dextral shear, which is distributed over the whole Japan Sea area, is accommodated by N‐S trending right‐lateral faults and rotation of blocks located between these right‐lateral faults.