A New Comb Circular Polarizer Suitable for Millimeter‐Band Application

This letter presents a new polarizer which has a simple comb structure inside a circular waveguide. The electrical performance of the proposed comb polarizer is optimized by a circular waveguide radius and by the physical parameters of the comb plates. This polarizer is suitable for providing good performance in millimeter‐band application because of its simple structure and low fabrication cost. In our experiments the dual‐band comb polarizer designed in band 1(K) and band 2(Ka) showed good electrical performance without any tuning elements.     

Note: High speed optical profiler based on a phase-shifting technique using frequency-scanning lasers

We present a high speed optical profiler (HSOP) using frequency-scanning lasers for three-dimensional profile measurements of microscopic structures. To improve upon previous techniques for implementing the HSOP, we developed frequency-scanning lasers and a compact microscopic interferometer. The controller of the HSOP was also modified to generate proper phase-shifting steps. For measurements of step height specimens, the HSOP showed results comparable with a commercial optical profiler, even with much higher measurement speeds (up to 30 Hz). The typical repeatability of step height measurement was less than 1 nm. We also present measurements of microscopic structures to verify the HSOP's ability to perform high speed inline inspection for the semiconductor and flat-panel display industries.     

AptaCDSS-E: A classifier ensemble-based clinical decision support system for cardiovascular disease level prediction

Conventional clinical decision support systems are generally based on a single classifier or a simple combination of these models, showing moderate performance. In this paper, we propose a classifier ensemble-based method for supporting the diagnosis of cardiovascular disease (CVD) based on aptamer chips. This AptaCDSS-E system overcomes conventional performance limitations by utilizing ensembles of different classifiers. Recent surveys show that CVD is one of the leading causes of death and that significant life savings can be achieved if precise diagnosis can be made. For CVD diagnosis, our system combines a set of four different classifiers with ensembles. Support vector machines and neural networks are adopted as base classifiers. Decision trees and Bayesian networks are also adopted to augment the system. Four aptamer-based biochip data sets including CVD data containing 66 samples were used to train and test the system. Three other supplementary data sets are used to alleviate data insufficiency. We investigated the effectiveness of the ensemble-based system with several different aggregation approaches by comparing the results with single classifier-based models. The prediction performance of the AptaCDSS-E system was assessed with a cross-validation test. The experimental results show that our system achieves high diagnosis accuracy (>94%) and comparably small prediction difference intervals (<6%), proving its usefulness in the clinical decision process of disease diagnosis. Additionally, 10 possible biomarkers are found for further investigation.     

Effect of interlayer on structure and performance of anode-supported SOFC single cells

To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57W/cm(2) at 800 degrees C and 0.44W/cm(2) at 700 degrees C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer.     

Polarization properties of cube-corner retroreflectors and their effects on signal strength and nonlinearity in heterodyne interferometers

The polarization properties of solid-state cube-corner retroreflectors, which are uncoated glass or metal-coated glass on the reflecting surfaces, are examined analytically and compared. Experimental verifications are presented for the case of linearly polarized incident light. When the uncoated cube-corner is used in a heterodyne interferometer, the polarization properties reveal that the axial orientation of the corner reflector has an effect on the strength of the beat signal and the nonlinearity error. A theoretical analysis of the effect is presented together with experimental results.     

Multiscale Bayesian texture segmentation using neural networks and Markov random fields

This paper presents a wavelet-based texture segmentation method using multilayer perceptron (MLP) networks and Markov random fields (MRF) in a multi-scale Bayesian framework. Inputs and outputs of MLP networks are constructed to estimate a posterior probability. The multi-scale features produced by multi-level wavelet decompositions of textured images are classified at each scale by maximum a posterior (MAP) classification and the posterior probabilities from MLP networks. An MRF model is used in order to model the prior distribution of each texture class, and a factor, which fuses the classification information through scales and acts as a guide for the labeling decision, is incorporated into the MAP classification of each scale. By fusing the multi-scale MAP classifications sequentially from coarse to fine scales, our proposed method gets the final and improved segmentation result at the finest scale. In this fusion process, the MRF model serves as the smoothness constraint and the Gibbs sampler acts as the MAP classifier. Our texture segmentation method was applied to segmentation of gray-level textured images. The proposed segmentation method shows better performance than texture segmentation using the hidden Markov trees (HMT) model and the HMTseg algorithm, which is a multi-scale Bayesian image segmentation algorithm.     

Molecular modeling study of CodX reveals importance of N-terminal and C-terminal domain in the CodWX complex structure of Bacillus subtilis

In Bacillus subtilis, CodW peptidase and CodX ATPase function together as a distinctive ATP-dependent protease called CodWX, which participates in protein degradation and regulates cell division. The molecular structure of CodX and the assembly structure of CodW-CodX have not yet been resolved. Here we present the first three-dimensional structure of CodX N-terminal (N) and C-terminal (C) domain including possible structure of intermediate (I) domain based on the crystal structure of homologous Escherichia coli HslU ATPase. Moreover, the biologically relevant CodWX (W(6)W(6)X(6)) octadecamer complex structure was constructed using the recently identified CodW-HslU hybrid crystal structure. Molecular dynamics (MD) simulation shows a reasonably stable structure of modeled CodWX and explicit behavior of key segments in CodX N and C domain: nucleotide binding residues, GYVG pore motif and CodW-CodX interface. Predicted structure of the possible I domain is flexible in nature with highly coiled hydrophobic region (M153-M206) that could favor substrate binding and entry. Electrostatic surface potential observation unveiled charge complementarity based CodW-CodX interaction pattern could be a possible native interaction pattern in the interface of CodWX. CodX GYVG pore motif structural features, flexible nature of glycine (G92 and G95) residues and aromatic ring conformation preserved Y93 indicated that it may follow the similar mode during the proteolysis mechanism as in the HslU closed state. This molecular modeling study uncovers the significance of CodX N and C domain in CodWX complex and provides possible explanations which would be helpful to understand the CodWX-dependent proteolysis mechanism of B. subtilis.     

Information processing using chaos with application to mobile robot navigation problems

Throughout this study on information processing using an artificial neural network (ANN) and chaos we are attempting to devise a memory model that resembles human behavioral characteristics. For that purpose we construct a framework of the macroscopic model of the responding process in biological systems. Incoming stimuli are applied to the sensory receptors and preprocessed. A pattern-matching block allows one of the chaotic memories to find a feasible response in an associative way. After the chaotic memory is stabilized on one of the stable equilibrium points or limit cycles, its performance is evaluated. Since chaotic memory and the performance evaluation block form a feedback loop, they can handle features of the information blocks and store newly updated information blocks. Two kinds of chaotic memories are established in this paper: one is a 1-D map in which many information blocks can be stored as unstable periodic orbits, and the other is the famous Lozi attractor with rich dynamics. Simulations are performed for the mobile robot navigation problem in each case. This work was presented, in part, at the Second International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1997     

Conductive adhesive with transient liquid‐phase sintering technology for high‐power device applications

A highly reliable conductive adhesive obtained by transient liquid‐phase sintering (TLPS) technologies is studied for use in high‐power device packaging. TLPS involves the low‐temperature reaction of a low‐melting metal or alloy with a high‐melting metal or alloy to form a reacted metal matrix. For a TLPS material (consisting of Ag‐coated Cu, a Sn96.5‐Ag3.0‐Cu0.5 solder, and a volatile fluxing resin) used herein, the melting temperature of the metal matrix exceeds the bonding temperature. After bonding of the TLPS material, a unique melting peak of TLPS is observed at 356 °C, consistent with the transient behavior of Ag₃Sn + Cu₆Sn₅ → liquid + Cu₃Sn reported by the National Institute of Standards and Technology. The TLPS material shows superior thermal conductivity as compared with other commercially available Ag pastes under the same specimen preparation conditions. In conclusion, the TLPS material can be a promising candidate for a highly reliable conductive adhesive in power device packaging because remelting of the SAC305 solder, which is widely used in conventional power modules, is not observed.