The paper reviews methods for the measurement and analysis of high precision surfaces. A number of measurement techniques are discussed with the emphasis on the application of con-focal methods. The various techniques are compared in terms of measurement times, data density, and the ability to detect near vertical surfaces, and steps. The two sensing methods discussed are the auto-focus laser method and the white light methods. Particular applications considered are in the measurement of eroded electrical contact surfaces, spherical and near spherical surfaces, and MEMS. The particular emphasis here is on the metrology of such surfaces and devices and methods for the assessment of complex micro-machined surfaces. The paper points to a number of directions for improved metrology and discusses these in the context of the application given.

A new scheme for evaluation of shapes of pips and craters formed by arc discharges on electrical contact surfaces is proposed. Measuring a height of a pip or a depth of a crater as well as an average diameter thereof with a scanning laser microscope and then putting a plot having the measured values as its vertical and horizontal coordinates enable us to numerically and briefly evaluate shapes of those pips and craters on arc-damaged contact surfaces. Some exemplary results obtained by this evaluation scheme are presented here.

We have developed a code-division-multiplexing (CDM) transmission scheme for future cellular communication systems, which uses cyclic shifted-and-extended (CSE) codes generated from an M-sequence to enable seamless communication in highly mobile environments. Because the correlation characteristics of CSE codes are determined by the M-sequence, the cross-correlation values are accumulated as a result of combining transmitted signals with opposite polarities in parallel channels. The accumulated cross-correlation values significantly degrade transmission performance, especially with multi-level modulation schemes such as quadrature amplitude modulation (QAM). We thus propose a cancellation technique to eliminate the accumulated cross-correlation values. We have evaluated the transmission performance of the CDM transmission scheme with the proposed technique by computer simulation. The new scheme enables high-quality data transmission in fast-fading channels.

The three major failures of electrical contacts for automotive relay applications are: contact welding (or contact sticking), high contact resistance and severe contact erosion due to switching arcing. With the demand of high power and multiple functions of automotive vehicles, the switching current has be dramatically increased, it results in higher failing rate, in particular for contact welding. On the other hand, the miniaturization of electromechanical relays has lead to the reduction of mechanical spring force. This not only results in the earlier contact welding but also makes the relay more susceptible to the contact resistance and arc erosion failures. This paper is a review of most recent studies on these three failure aspects. It describes the progress in the understanding of contact welding caused by short arcing and high contact resistance due to contamination of particles and films in relay manufacturing process and also it review the material transfer due to switching arcing. At the end, the brief considerations of electromechanical relays used in 42 volts have also been given.

We propose a new output arbitration method for an input buffered switch with a buffered crossbar. In the proposed method, each output selects the first nonempty buffer from the starting point. The starting points of output are determined to minimize the synchronization phenomenon that more than one input module sends cells destined for a same output. Using an approximate analysis of the synchronization phenomenon, we show the uniqueness of the starting points improves the switch performance. Finally, using computer simulations, we verify the proposed method outperforms the previous methods under the uniform and burst traffic.

We developed a new millimeter-wave plastic chip size package (CSP) to operate up to 100 GHz by using a thin-film substrate. It has a flip-chip distributed amplifier with inverted microstrip lines and the amplifier has a bandwidth of beyond 110 GHz. The transmission line on the substrate consists of grounded coplanar waveguides that yield low insertion loss and high isolation characteristics in coupled lines even in mold resin in comparison with conventional microstrip lines. The CSP amplifier achieved a gain of 7.8 dB, a 3-dB bandwidth of 97 GHz, and operated up to 100 GHz. To the best of our knowledge, this value is the highest operating frequency reported to date for a distributed amplifier sealed in a plastic CSP. We also investigated the transmission characteristics of lead-free solder bumps through experiments by assemblying CSPs on printed circuit boards and modeling them so that we could design the packages accurately.

We have developed a novel basic technology for terahertz (THz) imaging, which allows detection and identification of chemicals by introducing the component spatial pattern analysis. The spatial distributions of the chemicals were obtained from terahertz multispectral transillumination images, using absorption spectra previously measured with a widely tunable THz-wave parametric oscillator. We have also separated the component spatial patterns of frequency-dependent absorptions in chemicals and frequency-independent components such as plastic, paper and measurement noise in THz spectroscopic images. Further we have applied this technique to the detection and identification of illicit drugs concealed in envelopes.

The non-individualized head related transfer function (HRTF) is known to have a few problems, which are referred to as the 'hole in the middle' phenomenon and 'front-back reversals.' To overcome these problems, an HRTF refinement technique was introduced, but unfortunately, this refinement technique causes sudden degradation in sound quality and difficulty in cross-talk cancellation because of notch frequency exaggeration. In this paper, an HRTF refinement using directional weighting function is proposed. This newly proposed technique weights ordinary HRTF according to its direction to amplify frontal sound intensity. Since the proposed technique does not exaggerate the notch frequency, spectral differences in the 'cone-of-confusion' region become more pronounced within overall audible frequencies, resulting in mitigating the sound degradation. In addition, the cross-talk cancellation can be done more easily. We verified the superiority of the proposed technique over the existing one by means of the sound localization and sound quality tests in headphone and loudspeakers.

The present paper proposes differential transmission line structures on Si ULSI. Interconnect structures are examined using numerical results from a two-dimensional electromagnetic simulation (Ansoft, 2D Extractor). The co-planar and diagonal-pair lines are found to have superior characteristics for gigahertz signal propagation through long interconnects. The proposed diagonal-pair line can reduce the crosstalk noise and interconnect resource concurrently.

This paper presents the realization of the radio frequency (RF) power and data transmission for implantable microstimulators. This implantable device composes an internal RF front-end circuit, a control circuit, and a microstimulator. A 2 MHz AM-modulated signal including the power and data necessary for the implantable device is received, and a stable dc voltage and digital data will be extracted to further stimulate neuromuscular stimulation. In this implantable stimulator, the digital part is implemented by field programmable gate array (FPGA), and the analog part is implemented in a standard single-poly fifth-metal 0.25 µm CMOS process. The latter occupies a silicon area smaller than 0.00638 mm2 and produces an output current with 5-bit resolution for stimulations. The measuring stimulating current is 2.77 mA while the stimulation frequency is from 20 Hz to 2 kHz and the pulse width of stimulation current is from 100 µs to 450 µs. In addition, the simulation results of the RF front-end circuit and the verification of the control logic circuit are also presented in this paper.

The relative window method provides quantitative crosstalk delay degradation for the post-layout timing analysis in deep sub-micron VLSI design. However, to the best of our knowledge, the relative window method has not been applied to the crosstalk minimization in gridded channel routing problem. Most conventional crosstalk optimizers only use the coupling length to estimate the crosstalk. In this paper, we present a post-layout timing driven crosstalk optimizer based on the relative window method. According to the relative signal arrival time and the coupling length, we define a delay degradation graph to describe the crosstalks between nets in a routing solution. Our optimization goal is to maximize the time slack by iteratively improving the delay degradation graph without increasing the channel height. Benchmark data consistently show that our post-layout timing driven crosstalk optimizer can further improve the routing solution obtained by a conventional crosstalk optimizer.

Any utterances of dialogue, spoken language or sign language, have functions that enable recipients to achieve real-time and easy understanding and to control conversation smoothly in spite of its volatile characteristics. In this paper, we present evidence of these functions obtained experimentally. Prosody plays a very important role not only in spoken language (aural language) but also in sign language (visual language) and finger braille (tactile language). Skilled users of a language may detect word boundaries in utterances and estimate sentence structure immediately using prosody. The gestures and glances of a recipient may influence the utterances of the sender, leading to amendments of the contents of utterances and smooth exchanges in turn. Individuality and emotion in utterances are also very important aspects of effective communication support systems for persons with disabilities even more so than for those non-disabled persons. The trials described herein are universal in design. Some trials carried out to develop these systems are also reported.

This paper proposes a noise robust speech recognition method using prosodic information. In Japanese, the fundamental frequency (F0) contour represents phrase intonation and word accent information. Consequently, it conveys information about prosodic phrases and word boundaries. This paper first describes a noise robust F0 extraction method using the Hough transform, which achieves high extraction rates under various noise environments. Then it proposes a robust speech recognition method using multi-stream HMMs which model both segmental spectral and F0 contour information. Speaker-independent experiments are conducted using connected digits uttered by 11 male speakers in various kinds of noise and SNR conditions. The recognition error rate is reduced in all noise conditions, and the best absolute improvement of digit accuracy is about 4.5%. This improvement is achieved by robust digit boundary detection using the prosodic information.

In the present paper, we evaluate the inter-cell interference of AS-CDMA systems. First, the cross-correlation property of AS-CDMA systems is examined by theoretical study in order to clarify the fundamental feature of the inter-cell interference. The result shows that the influence of one interference terminal in each adjacent cell is dominant regardless of whether approximate synchronization is maintained. Next, the ratio of interference signal power and desired signal power is evaluated by computer simulation. The simulation result shows that total interference power does not increase even when approximate synchronization is not maintained.

Finite-ground microstrip line (FGMSL) open-end discontinuities are characterized via a self-calibrated method of moments (MoM) as a unified circuit model with a fringing capacitance and radiation conductance. By integrating the short-open calibration (SOC) procedure into a determinant MoM, the model parameters are extracted without needing the alternative port impedance. Regardless of non-ideal voltage sources, extracted parameters are observed to achieve a stable convergence as the feeding line is sufficiently extended. After extracted capacitance of a FGMSL open-end with equal strip and finite-ground widths are validated against its traditional MSL counterpart with infinite ground, extensive results are given to originally demonstrate that the capacitance increases as a decelerated function of the finite-ground width and length while the conductance is negligibly small as compared with its imaginary part.

In this letter, the concept of cross-entropy is introduced for unsupervised polarimetric synthetic aperture radar (SAR) image classification. The difference between two scatterers is decomposed into three parts, i.e., the difference of average scattering characteristic, the difference of scattering randomness and the difference of scattering matrix span. All these three parts are expressed in cross-entropy formats. The minimum cross-entropy principle is adopted to make classification decision. It works well in unsupervised terrain classification with a NASA/JPL AIRSAR image.

We have shown that a photonic sensor can be used as an electric-field probe for planar near-field measurements of X-band antennas. Because an antenna on the photonic sensor is small (about 0.1 λ) compared to the wavelength, the photonic sensor can directly measure the amplitude and the phase of the electric field close (about 0.3 λ) to the apertures of antennas without disturbing the electric field to be measured. Therefore we can obtain the antenna pattern by transforming the measured electric field without probe compensation. To verify the merits of the photonic sensor, we have evaluated the antenna patterns of a standard gain horn antenna and a microstrip array antenna at 9.41 GHz. Comparing the results obtained using the photonic sensor with those obtained using the conventional open-ended waveguide probe and other methods, we have shown that the antenna patterns agree with each other within 1 dB over wide ranges of directivity.

We present an overview of our work on the application of scanning near-field optical microscopy (SNOM) to photonic crystal structures. Our results show that SNOM can be used to map the subwavelength confinement of light to a point-defect in a 2D photonic crystal microresonator. Comparison with numerical modelling shows that SNOM is able to resolve patterns in the intensity distribution that are due to the slight non-uniformity in the crystal structure. We also discuss the future possibilities for applications of different modes of SNOM to photonic crystal devices.

This paper studies the propagation and crossing of signals in cellular automata whose cells are updated at random times. The signals considered consist of a core part, surrounded by an insulating sheath that is missing at the side of the core that corresponds to the direction into which the signal moves. We study two types of signals: (1) signals by which the sheath at the left and right sides of the core advance first in a propagation step, followed by the core, and (2) signals by which the core advances first, followed by the sheath at its left and right sides. These types naturally arise in, respectively, Moore neighborhood cellular automata with semi-totalistic rules and von Neumann neighborhood cellular automata with symmetric transition rules. The type of a signal has a profound impact on the way signals cross each other, as we show by the construction of one signal of each type. The results we obtained should be of assistance in constructing asynchronous circuits on asynchronous cellular automata.

Polyurethane elastomer (PUE) films similar to polymer gel materials have been found to exhibit the electrostriction effect. We proposed the application their to a moving device such as an actuator without ionic solvent using the electrostriction effect of PUE. The actuators are of monomorph type fabricated by PUE film and metal electrodes evaporated at different thicknesses on the film surface. Because these actuators work at high voltage more than 1 KV, we controlled the molecular structure of the films by doping C60 derivatives (fullerenol) into PUE so that the actuators could operate under a low voltage. In order to clear the bending mechanism of actuators, we measured the space charge of PUE films using the pulsed electroacoustic method.