To classify the significant wavelet coefficients into edge area and noise area, a morphological clustering filter applied to wavelet shrinkage is introduced. New methods for wavelet shrinkage using morphological clustering filter are used in noise removal, and the performance is evaluated under various noise conditions.

A circuit that carries out an Hadamard transform of an input image using the pulse width modulation technique is proposed. The proposed circuit architecture realizes the function of an Hadamard transform with a full-size pixel image. A test chip that we designed and fabricated integrates 64 64 pixels in a 4.9 mm 4.9 mm area, with 0.35 µm CMOS technology. The functional operation and linearity of this chip are measured. An image processing application utilizing this chip is demonstrated.

A novel formulation for the Scalar-field approach of Integral Equation formulation of the Measured Equation of Invariance (SIE-MEI) is derived from the scalar reciprocity relation to solve the scalar Helmholtz equation. The basics of this formulation are similar to IE-MEI method for the electromagnetic (EM) problem. The surface integral equation is derived from reciprocity relation and on-surface MEI postulates are used. As a result it generates a sparse linear system with the same number of unknowns as of Boundary Element Method (BEM) and keeps the merits in minimum storage memory requirements and CPU time consumption for computing the final matrix. IE-MEI method has been proposed for two-dimensional (2D) electromagnetic problem, but three-dimensional (3D) problem is very difficult to be extend. This scalar-field approach of IE-MEI method is identical to electromagnetic in 2D, but easily extended to the 3D scalar-field scattering problem contrary to EM problem. The numerical results of sphere and cube are verified with some rigorous or numerical solutions, which give excellent agreement.

A new blocking artifact reduction algorithm is proposed that uses block classification and feedforward neural network filters in the spatial domain. At first, the existence of blocking artifact is determined using statistical characteristics of neighborhood block, which is then used to classify the block boundaries into one of four classes. Thereafter, adaptive inter-block filtering is only performed in two classes of block boundaries that include blocking artifact. That is, in smooth regions with blocking artifact, a two-layer feedforward neural network filters trained by an error back-propagation algorithm is used, while in complex regions with blocking artifact, a linear interpolation method is used to preserve the image details. Experimental results show that the proposed algorithm produces better results than the conventional algorithms.

A new system, in which a real-time VLBI (very-long-baseline interferometer) is utilized, for real-time monitoring of atmospheric disturbances on a very-long baseline has been developed. In this system, beacon waves from geo-stationary satellites are used for received signals and public communication lines are used for data transmission. Connecting the system to the 6-m Kagoshima and the 10-m Mizusawa radio telescopes enables atmospheric disturbances to be observed. The cross-correlation phase was calculated from the received signals, and the Allan standard deviation of the phase was obtained. It was found that the Allan standard deviation across almost the whole region of the time interval reflects atmospheric disturbances.

Experiments were conducted to examine an approach from language modeling side to improving noisy speech recognition performance. By adopting appropriate word strings as new units of processing, speech recognition performance was improved by acoustic effects as well as by test-set perplexity reduction. Three kinds of word string language models were evaluated, whose additional lexical entries were selected based on combinations of part of speech information, word length, occurrence frequency, and log likelihood ratio of the hypotheses about the bigram frequency. All of the three word string models reduced errors in broadcast news speech recognition, and also lowered test-set perplexity. The word string model based on log likelihood ratio exhibited the best improvement for noisy speech recognition, by which deletion errors were reduced by 26%, substitution errors by 9.3%, and insertion errors by 13%, in the experiments using the speaker-dependent, noise-adapted triphone. Effectiveness of word string models on error reduction was more prominent for noisy speech than for studio-clean speech.

A Multiwavelength Brillouin/Erbium fibre laser which operates in long-wavelength band (L-band) is demonstrated with an approximate comb spacing of 10 GHz. The laser configuration consists of a long EDF to enable the L-band amplification and two 3-dB couplers to take a portion of the generated BEFL signal and re-inject it into the SMF to seed a cascaded BEFL line in the same direction as the first BEFL line. 20 lines including the anti-Stokes are obtained with the maximum Brillouin pump and 980 nm-pump power of 8.9 mW and 92 mW, respectively.

Software with design flaws increases maintenance costs, decreases component reuse, and reduces software life. Even well-designed software tends to deteriorate with time as it undergoes maintenance. Work on restructuring object-oriented designs involves estimating the quality of the designs using metrics, and automating transformations that preserve the behavior of the designs. However, these factors have been treated almost independently of each other. A long-term goal is to define transformations preserving the behavior of object-oriented designs, and automate the transformations using metrics. In this paper, we describe a genetic algorithm based restructuring approach using metrics to automatically modify object-oriented designs. Cohesion and coupling metrics based on abstract models are defined to quantify designs and provide criteria for comparing alternative designs. The abstract models include a call-use graph and a class-association graph that represent methods, attributes, classes, and their relationships. The metrics include cohesion, inheritance coupling, and interaction coupling based on the behavioral similarity between methods extracted from the models. We define restructuring operations, and show that the operations preserve the behavior of object-oriented designs. We also devise a fitness function using cohesion and coupling metrics, and automatically restructure object-oriented designs by applying a genetic algorithm using the fitness function.

In this paper, we focus on an OFDM peak power reduction method that uses clipping and filtering. This method can reduce the peak power of OFDM via clipping, and can also reduce the out-band emission via filtering, even if a nonlinear amplifier is used. However, the filtering causes peak power regeneration. For purposes of reducing the effect of peak power regeneration, we propose an adaptive clipping level control method for OFDM peak power reduction, as part of a technique using clipping and filtering. In this method, the clipping level is optimized by checking the peak power regrowth which is caused by inserting a filter, by using a multi-stage filtering simulator. Thus the peak power is adjusted to the target PAPR. If the target PAPR is decided to be the saturation power of an amplifier, the bit error rate performance is improved without increasing the out-band emission. In order to confirm the effectiveness of the proposed system, we evaluate its performance by using computer simulation.

Reactive near field reflection characteristics of commercial RF absorbers are investigated to determine the minimum size of a reactive-field anechoic box necessary for measuring the reactive near field of an ESPAR antenna. The reflectivity of the absorber placed in close proximity to an antenna is inversely proportional to the distance between the antenna and the absorber. For carbon filled urethane foam tapered absorbers, we find that the backscattered reflection characteristics mainly depend on their tapered height rather than the thickness of absorber base. As a result, we show that carbon filled urethane foam pyramidal and wave surface shaped absorbers can be used to make reactive-field anechoic boxes. A prototype of a reactive-field anechoic box is presented and the distance from the absorber to the antenna is reduced to a wavelength. The prototype is verified by comparing its performance with that obtained from a large anechoic chamber.

This paper presents a new method of designing a dither matrix based on simulated annealing. An obtained dither matrix (halftone screen/mask) is appropriate for press printing. Because of several physical reasons, halftoning for press printing is more difficult than halftoning for electronic displays, or ink-jet printers. Even if stochastic dispersed-dot screening (so-called FM-screening) is one of the best solutions for halftoning, that is not appropriate for press printing. On the other hand, classical periodic clustered-dot screening (so-called AM-screening) is more important and is widely used even now. We recognize unfavorable quality of AM-screening, but we can not ignore its productive stability in printing section. The proposed halftone dither matrix has aperiodic clustered-dot pattern, and size of cluster can be controlled by a weighting parameter of a cost function. We will obtain a dither matrix which consists of clustered-dots. Some characteristics of the design algorithm and halftoned images are investigated in detail. As a result, the fact that an obtained dither matrix is superior to AM-screen and comparable to FM-screen in visual quality, and the matrix is comparable to AM-screen and superior to FM-screen in press printability is confirmed.

This paper proposes a new blocking artifact reduction algorithm using an adaptive filter based on classifying the block boundary area. Generally, block-based coding, such as JPEG and MPEG, introduces blocking and ringing artifacts to an image, where the blocking artifact consists of grid noise, staircase noise, and corner outliers. In the proposed method, staircase noise and corner outliers are reduced by a 1D low-pass filter. Next, the block boundaries are divided into two classes based on the gradient of the pixel intensity in the boundary region. For each class, an adaptive filter is applied so that the grid noise is reduced in the block boundary regions. Thereafter, for those blocks with an edge component, the ringing artifact is removed by applying an adaptive filter around the edge. Finally, high frequency components are added to those block boundaries where the natural characteristics have been lost due to the adaptive filter. The computer simulation results confirmed a better performance by the proposed method in both the subjective and objective image qualities.

In this paper, we discuss the applicability of H filtering algorithm for a decision feedback equalizer (DFE) in mobile communications environments. A comparison of bit error rate (BER) performance between a H2 filtering (recursive least squares) algorithm-based and an a priori H filtering algorithm-based fractionally-tap-spaced DFEs in various fading channels is presented. Against, our results are rather pessimistic of the H equalizer, namely, as compared with the H2 equalizer, at most the same or a little better BER performance of the H equalizer is obtained only when the ratio of the average received energy per bit to the white noise power spectral density and the normalized fading rate are large enough, especially in Rician fading channels. Moreover, the H equalizer has the problems of how to choose an appropriate prescribed positive value and computational complexity, therefore it may not be considered as an attractive alternative to the H2 equalizer for wireless communications systems.

Double Cross Cylinder (DCC) is an object created by intersecting the cylinder of Y-axis and the cylinder of the Z-axis. DCC mapping is a new method for effectively mapping the environment. This method eliminates the singularity effect caused in the environment maps and shows an almost even amount of area for the environment occupied by a single texel. The surrounding environment can also be stored more effectively through more accurate sampling. Improvement is also achieved in the rendering time of the DCC mapping method and octahedral mapping method based on DCC mapping. Therefore, the DCC mapping method is suitable to be applied on environment navigation systems due to its effective storage of the environment and faster sampling time.

This paper discusses a new type of semi-supervised document clustering that uses partial supervision to partition a large set of documents. Most clustering methods organizes documents into groups based only on similarity measures. In this paper, we attempt to isolate more semantically coherent clusters by employing the domain-specific knowledge provided by a document analyst. By using external human knowledge to guide the clustering mechanism with some flexibility when creating the clusters, clustering efficiency can be considerably enhanced. Experimental results show that the use of only a little external knowledge can considerably enhance the quality of clustering results that satisfy users' constraint.

Carbon-gold (C-Au) film was formed by co-operation process of plasma CVD and sputtering with using methane and Ar mixture gas and gold plate discharge electrode. Refractive index of 3.1 for the film was obtained at Au atom content of 5.5 atomic%. The optical transmittance was improved significantly in the visible light wavelength range compared to the C-S-Au film reported previously. Au atom distribution in the C-Au film and the electronic polarizabilities were discussed in the relation to the refractive index.

A visual secret sharing scheme (VSSS) is one of secret sharing schemes for images. Droste showed the method for constructing VSSS based on basis matrices whose contrast was high. Koga, Iwamoto, and Yamamoto also proposed the method for constructing a lattice-based VSSS and its polynomial representation. It is known that many good VSSSs are not in the class of lattice-based VSSSs. In this paper, we show the well-defined polynomial representation of a VSSS based on permuting different matrices for black-white images. The necessary and sufficient condition of the existence of a VSSS based on permuting different matrices can be obtained from the proposed polynomial representation. This condition is useful for constructing a good VSSS. We also point out that without additional data, it is possible to achieve member verification by using a VSSS. Using the proposed polynomial representation, the probability of detecting a cheater is analyzed.

The concept of the equi-phase curve is introduced for the cross-polarized channel case. It is proved that the equi-phase curves are a series of half circles on the Poincare sphere, and that all these curves have two common ends. Based on the introduced concept, this letter demonstrates the distribution of the received voltage's phases on the Poincare sphere. In addition, it is shown theoretically that the cross-polarized phase of the off-diagonal elements of a scattering matrix is unstable for most natural targets. Therefore, the cross-polarized phase information cannot be used for extracting target characteristics in polarimetric radar remote sensing.

A new type of electromagnetic vibration transducer for use in an IME (implantable middle ear) system is presented and evaluated by in-vitro experiment. Because the new designed transducer includes two magnets glued together with the same pole facing inside the coil, it can reduce the interference from an environmental magnetic field. And the proposed transducer exhibits a high vibration efficiency and wide frequency response. Using dead human's temporal bone, in-vitro experiments were carried out and the results showed that the proposed vibration transducer will be properly used to implantable middle ear for mild to severe hearing loss patients.

There are several kinds of coloring of digraphs, such as vertex-coloring and arc-coloring. We call an arc-coloring of a digraph G the first type if it is an assignment of colors to the arc set of G in which no two consecutive arcs have the same color. In some researches, the arc-coloring of first type has been associated with the minimum number of the vertex-coloring called chromatic number. Considering the class of line digraphs, an arc-coloring of a digraph G of the first type is equivalent to the vertex-coloring of its line digraph L(G). In this paper, we study the arc-coloring of the first type and the vertex-coloring of line digraphs. We give the upper bound of the chromatic number of L(G) by the chromatic number of a digraph G which admits loops. It is also shown that there exists quite a small integer k so that the iterated line digraph Lk(G) is 3-vertex-colorable. As a consequence, we derive the chromatic number of de Bruijn and Kautz digraphs.