Recently, DOAS (differential optical absorption spectroscopy) has been used for nondestructive air monitoring, in which the LS (least squares) method is used to calculate trace gas concentrations due to its computational simplicity. This paper applies the ICA (independent component analysis) method to the DOAS system of air monitoring, since the LS method is insufficient to recover the desired spectra perfectly due to sparsity characteristic. If the sparsity of reference spectra in the DOAS system imposes the assumption of independence, the ICA algorithm can be used. The proposed method is used to regress the observed spectrum on the estimates of the reference spectra. The ICA algorithm can be seen as a preprocessing method where the ICs of the references are used as the input in the regression. The performance of the proposed method is evaluated in simulation studies using synthetic data.

This paper proposes near-field sound-source localization based on crosscorrelation of a signed binary code. The signed binary code eliminates multibit signal processing for simpler implementation. Explicit formulae with near-field assumption are derived for a two microphone scenario and extended to a three microphone case with front-rear discrimination. Adaptive threshold for enabling and disabling source localization is developed for robustness in noisy environment. The proposed sound-source localization algorithm is implemented on a fixed-point DSP. Evaluation results in a robot scenario demonstrate that near-field assumption and front-rear discrimination provides almost 40% improvement in DOA estimation. A correct detection rate of 85% is obtained by a robot in a home environment.

The exact calculation of the ergodic and outage capacity for Rayleigh fading single-input multiple-output (SIMO) channels in the presence of unequal-power Rayleigh fading interferers is mathematically quite challenging due to the complicated distribution of the capacity. In this paper, a SIMO system with M receive antennas and N interferers is considered. Based on some statistical results, the closed-form upper and lower bound for the ergodic and outage capacity are derived respectively. These bounds are shown to be simple to compute and appear to be quite tight.

This paper presents two novel blind set-theoretic adaptive filtering algorithms for suppressing "Multiple Access Interference (MAI)," which is one of the central burdens in DS/CDMA systems. We naturally formulate the problem of MAI suppression as an asymptotic minimization of a sequence of cost functions under some linear constraint defined by the desired user's signature. The proposed algorithms embed the constraint into the direction of update, and thus the adaptive filter moves toward the optimal filter without stepping away from the constraint set. In addition, using parallel processors, the proposed algorithms attain excellent performance with linear computational complexity. Geometric interpretation clarifies an advantage of the proposed methods over existing methods. Simulation results demonstrate that the proposed algorithms achieve (i) much higher speed of convergence with rather better bit error rate performance than other blind methods and (ii) much higher speed of convergence than the non-blind NLMS algorithm (indeed, the speed of convergence of the proposed algorithms is comparable to the non-blind RLS algorithm).

This paper presents a 2-D model for calculating the current density distribution and the flux-flow resistivity of a Melt Cast Process BSCCO 2212 rod during the quenching process in self field with large current density. Based on the forces analysis of the flux-line lattice, the equilibrium equation for the 2-D viscous flux motion is derived from the model. With this equation, the current density distribution and the flux density distribution are obtained in not only the critical state but also the flux-flow state. Subsequently, the average flux-flow resistivity is calculated with the knowledge of the 2-D field distribution. The calculation results are in accordance with the experimental results. Finally, the applications of the 2-D model are extended to the superconducting tube and the low-Tc superconductor.

This paper presents the results of an investigation on the effect of a thin low-dielectric material (phantom shell) on measuring the Specific Absorption Rate (SAR) in the frequency range of 3 to 6 GHz. The International Electrotechnical Commission (IEC) has started to develop a SAR measurement procedure in order to cover such frequencies. In the procedure, the SAR is measured in a liquid phantom, which is a shell filled with tissue-equivalent liquid. Although the shell is thin and has low-dielectric properties, the influence of the phantom shell is thought to increase at higher frequencies. Therefore, an investigation using the transmission line model and the Finite-Difference Time-Domain (FD-TD) method was conducted. To verify the FD-TD results, measurements were also carried out. The calculation results using the FD-TD method agree well with the measurement results. If the frequency is higher, the SAR is affected by the shell even though the shell is thinner and has much lower dielectric properties than those of the tissue-equivalent liquid. Specifically, the SAR with the shell is approximately 1.3 times higher than without the shell at 5.2 GHz for the maximum case. The deviations in the loss and the thickness for the shell do not affect the SAR more than the relative permittivity.

We initiated development of our own data processing software for laser microscope data with C# language. This software is provided with volume calculation function of a target portion, based on a new calculation algorithm that can precisely handle the volume calculation of the portion located on a tilted surface or on a distorted surface. In this paper, this algorithm and some exemplary results obtained thereby, as well as some further development aims, are briefly described.

Carbon brushes for starters are used under severe conditions of high electric current density, high contact pressure and high sliding velocity. Lead has traditionally been added to carbon brushes to improve their performance and durability. Because lead is an environmentally hazardous substance, after January 2005 the EU will prohibit adding lead to carbon brushes for electric motors installed in vehicles. The purpose of our current study is to develop materials of lead-free carbon brushes for starters. Analyzing the effects of adding lead has shown that lead inhibits the brush resistance from increasing under high temperatures, or a combination of both high temperature and high humidity. This is because corrosion of lead precedes that of copper, which is one of the materials comprising the brush, and this prevents the copper from corroding. Moreover, lead functions as a solid lubricant and reduces brush wear. We developed the lead-free brush material, by adding soft metallic substances that corrode prior to copper and are also oxidation-resistant, as well as possessing low hardness and solid lubricant properties. The developed lead-free brush surpasses the conventional lead-added brush in durability and permanence.

This paper considers the problem of finding two-dimensional (2-D) direction of arrivals (DOAs) for coherent cyclostationary signals using a 2-D array with random position errors. To alleviate the performance degradation due to the coherence between the signals of interest (SOIs) and the random perturbation in 2-D array positions, a matrix reconstruction scheme in conjunction with an iterative algorithm is presented to reconstruct the correlation matrices related to the received array data so that the resulting correlation matrices possess the eigenstructures required for finding 2-D DOAs. Then, using the reconstructed matrices, we create a subspace orthogonal to the subspace spanned by the direction vectors of the SOIs. Therefore, the 2-D DOAs of the SOIs can be estimated based on a subspace-fitting concept and the created subspace. Finally, several simulation examples are presented for illustration and comparison.

Self-connection can enlarge the memory capacity of an associative memory based on the neural network. However, the basin size of the embedded memory state shrinks. The problem of basin size is related to undesirable stable states which are spurious. If we can destabilize these spurious states, we expect to improve the basin size. The inverse function delayed (ID) model, which includes the Bonhoeffer-van der Pol (BVP) model, has negative resistance in its dynamics. The negative resistance of the ID model can destabilize the equilibrium states on certain regions of the conventional neural network. Therefore, the associative memory based on the ID model, which has self-connection in order to enlarge the memory capacity, has the possibility to improve the basin size of the network. In this paper, we examine the fundamental characteristics of an associative memory based on the ID model by numerical simulation and show the improvement of performance compared with the conventional neural network.

This paper proposes an efficient two-phase optimization approach for a compact W-band double-plane stepped rectangular waveguide filter design, which combines genetic algorithms (GAs) with the simplified transmission-line model and full-wave analysis. Being more efficient and robust than the gradient-based method, the approach can lead to a compact waveguide filter design. Numerical results show that the resultant waveguide filter design with 4 sections (total length 19.6 mm) is sufficient to meet the design goal and provides comparable performance to that with 8 sections (total length 35.6 mm) by the Chebyshev synthesis approach. Based on the present approach, nineteen compact high-pass waveguide filters have been implemented and measured at the W-band with satisfactory performance.

Polarimetric calibration of radar is indispensable for using radar data effectively. This paper proposes a polarimetric radar calibration algorithm using polarization-preserving and polarization-selective reflectors as reference targets. The algorithm assumes radar antenna reciprocity but allows different co-polarization transmission characteristics between horizontal and vertical polarization channels. In processing, the second order terms of small cross-talk factors in antenna polarization transfer characteristics are ignored. The major advantage of the present algorithm is that it does not need assumptions on the scattering characteristics of the background natural surface and is independent of external phase calibration. The results of error analysis show that the present algorithm has sufficient tolerance against errors of reference targets. The validity of the present algorithm was evaluated by analyzing the Spaceborne Imaging Radar C (SIR-C) data and the results were satisfactory.

Animation video is becoming very popular with the availability of low cost computing resources. The cell animation is a popular method, used for producing animation video. In order to efficiently encode these videos, conventional video codecs, such as AutoDesk Animation Pro FLC, Intel Indeo 5, and MPEG-4 can be used to achieve high compression. However, when cell animation videos are compressed at very low bit rate by these traditional codecs, objectionable artifacts, e.g., false color, blurred contours, and blocking artifact, are severely occurred. In this paper, we propose an efficient compression method for cell animation images. The proposed method employs hybrid coding scheme which includes intraframe and interframe coding modes. The intraframe mode consists of color quantization, adaptive differential pulse code modulation, forward classification, and Golomb-Rice coding. The interframe coding consists of block-based techniques and exploits the characteristics of motion. Simulation results show that the proposed method provides superior performance over AutoDesk Animation Pro FLC, MPEG-1, Intel Indeo 5, and MPEG-4 standards.

In this paper we focus on the decoding error of the Log-Likelihood Ratio Belief Propagation (LLR-BP) decoding algorithm caused by oscillation. The decoding error caused by the oscillation is dominant in high Eb/N0 region. Oscillation of the LLR of the extrinsic value in the bit node process (ex-LLR) is propagated to the other bits and affects the whole decoding. The Ordered Statistic Decoding (OSD) algorithm is known to improve the error rate performance of the LLR-BP decoding algorithm. The OSD algorithm is performed by deciding the reliability of each bit based on a posteriori probability. In this paper we propose two decoding algorithms based on two types of oscillations of LLR for LDPC codes. One is the oscillation-based OSD algorithm with deciding the reliability of each bit based on oscillation. The other is the oscillation-based LLR-BP decoding algorithm that modifies ex-LLR based on oscillation. In the oscillation-based LLR-BP decoding algorithm, when ex-LLR oscillates, then we reduce the magnitude of this ex-LLR to reduce the effects on the other bits. Both algorithms improve the decoding errors caused by oscillation. From the computer simulations, we show that paying attention to the oscillation, we can improve the error rate performance of the LLR-BP decoding algorithm.

This paper proposes hardware-efficient VLSI architectures for 2-channel signal word decomposed filters (2-ch SWDFs) and their design method in consideration of the implemented circuit size. By consideration of the circuit size in design method, 2-ch SWDFs with a minimum output error among SWDFs whose size is equal to or smaller than a specification can be designed. Canonical Signed Digit expressions are used to effectively represent the filter coefficients of the SWDFs in order to make its circuit size small. Through precise analysis of the internal structures, circuit size can be accurately estimated. Some design examples show that the proposed method can design filters whose output error is about -12 dB lower than that of the linear FIR filters. Compared to an exhaustive search method, our method is much faster and can design filters whose output errors are only about 2 dB more.

It is well known that both shape and motion can be factorized directly from the measurement matrix constructed from feature points trajectories under orthographic camera model. In practical applications, the measurement matrix might be contaminated by noises and contains outliers. A direct SVD (Singular Value Decomposition) to the measurement matrix with outliers would yield erroneous result. This paper presents a novel algorithm for computing SVD with outliers. We decompose the SVD computation as a set of alternate linear regression subproblems. The linear regression subproblems are solved robustly by applying the RANSAC strategy. The proposed robust factorization method with outliers can improve the reconstruction result remarkably. Quantitative and qualitative experiments illustrate the good performance of the proposed method.

In order to provide an efficient test method for PLL which is a mixed-signal circuit widely used in most of SoCs, a novel BIST method is developed. The new BIST uses the change of phase differences generated by selectively alternating the feedback frequency. It provides an efficient structural test, reduces an area overhead and improves the test accessibility.

Electromagnetic field probes inevitably disturb the original distribution of the field when they are positioned close to a device. This disturbance in turn affects measurement accuracy and device operation. We developed an optical magnetic field probe, comprising a loop antenna element and an electro-optic crystal, for highly accurate magnetic near-field measurement in the GHz frequency range. We analyzed the invasiveness of the optical magnetic field probe quantitatively both experimentally and using finite difference time domain simulation. We found that eliminating the metal cable reduced the disturbance of the surrounding field that was to be measured. In addition, we investigated the magnetic field detection characteristics of the probe and its influence on the operation of a microstrip line. The optical magnetic field probe was less invasive and provided more accurate measurement.

A distributed network-oriented Intrusion Detection System (IDS) is a mechanism which detects misuse accesses to an intra-network by distributed IDSs on the network with decomposed attack scenarios. However, there are only ad hoc algorithms for determining a deployment of distributed IDSs and a partition of the attack scenarios. In this paper, we formally define this problem as the IDS partition deployment problem and design an efficient algorithm for a simplified version of the problem by graph theoretical techniques.

In this paper, a balance-unbalance conversion factor (TCTL: Transverse Conversion Transfer Loss, TCL: Transverse Conversion Loss) and a radiated emission for differential type microstrip lines with a partial unbalance on a PCB (Printed Circuit Board) are investigated. As the result, after inserting an unbalance element, it can be seen that a radiated emission increased according to the deterioration of TCL. The calculated results of the TCTL and TCL by using 4-terminal pair network chain matrix agreed with the measured results very well. In order to calculate radiated emission from the differential type microstrip lines, a common mode current on differential type microstrip lines with a partial unbalance was calculated by using 4-terminal pair network chain matrix. The calculated results of the radiated emission also agreed with the measured results.