Pitch frequency is a basic characteristic of human voice, and pitch extraction is one of the most important studies for speech recognition. This paper describes a simple but effective technique to obtain correct pitch frequency from candidates (pitch candidates) extracted by the short-range autocorrelation function. The correction is performed by a neural network in consideration of the time coutinuation that is realized by referring to pitch candidates at previous frames. Since the neural network is trained by the back-propagation algorithm with training data, it adapts to any speaker and obtains good correction without sensitive adjustment and tuning. The pitch extraction was performed for 3 male and 3 female announcers, and the proposed method improves the percentage of correct pitch from 58.65% to 89.19%.

For the study of the biological effects of ELF (Extremely Low Frequency) electric fields, the perception mechanism of ELF electric fields was analyzed. When a human body is exposed to an electric field, the hair on the body surface moves due to the electric force exerted on the hair. In theoretical analysis, it was shown that the force is approximately proportional to the dielectric constant of hair and the spatial gradient of the square of the electric field at the hair. The dielectric constant of hair was measured with different temperatures and humidities of the surrounding air. A technique was developed to estimate the electric force exerted on a hair during the field exposure. After experiments with model hair, the technique was applied to a body hair of a living human being. It was found that the force increased with field strength and relative humidity. The variations of the force agreed well with those expected from the theoretical analysis and the measurement of hair dielectric constants. These results explain the cause of the reported variation in the threshold of biological effects of an electric field. The results will help to establish a practical safety standard for the held exposure.

The generation and design of a stationary Markov signal are discussed as an inverse problem, in which one looks for a transition probability when a stationary probability distribution is given. This paper presents a new solution to the inverse problem, which makes it possible to design and generate a Markov random signal with arbitrary probability distribution and an exponential correlation function. Several computer results are illustrated in figures.

An 18-kb RAM with 9-kgate control logic gates operating during a cycle-time of 1.5 ns has been developed. A pseudo-dual-port RAM function is achieved by a two-bank structure and on-chip control logic. Each bank can operate individually with different address synchronizing the single clock. A sense-amplifier with a selector function reduces the reading propagation time. Bonded SOI wafers reduce the memory-cell capacitance, and this results in a fast write cycle without sacrificing α-particle immunity. The chip is fabricated in a double polysilicon self-aligned bipolar process using trench isolation. The minimum emitter size is 0.52 µm2 and the chip size is 1111 mm2.

Efficiency of Cerenkov-radiation-type second harmonic generation with absorption loss for second harmonic wave is analytically estimated. Output power reduction for attenuation coefficient of 2.0104 cm1 is calculated 37% (63% output of lossless case). Blue SHG at 443.5 nm is observed by a poled polymer pNAn-PVA waveguide. The wavelength is shorter than the cut-off wavelength of 480 nm.

The optical waveguides containing phthalocyanine as an optically active material were fabricated and transmission properties were investigated experimentally and numerically. The positive refractive index change was observed in the glass waveguide with a vanadyl phthalocyanine thin film as a top layer. The thermal influence on refractive index change was estimated by surface plasmon measurements.

This paper presents a structure of adaptive equalizer equipped with a neural network and a Viterbi decoder, and evaluates its performance under a fading environment by means of computer simulation.

This paper discusses fully digital error correction and self-calibration which correct errors due to capacitor mismatch, charge injection, and comparator offsets in algorithmic A/D converters. The calibration is performed without any additional analog circuitry, and the conversion does not need extra clock cycles. This technique can be applied to algorithmic converter configurations including pipelined, cyclic, or pipelined cyclic configurations. To demonstrate the concept, an experimental 2-stage pipelined cyclic A/D converter is implemented in a standard 1.6-µm CMOS process. The ADC operates at 600 ks/s using 45 mW of power at2.5 V supplies. The active die area excluding the external logic circuit is 1 mm2. Maximum DNL of 0.6 LSB and INL of 1 LSB at a 12-b resolution have been achieved.

Electrical and optical properties of organic multilayer structure have been investigated. Two types of current-voltage characteristics have been found for thin multilayer structure of organic films. Optical property and its application for electroluminescent diode have been presented. The diode characteristics have been discussed in terms of energy band scheme.

An adaptive method analyzing analytic speech signals is proposed in this paper. The method decreases the errors of finite precision on calculation in a method with real coefficients. It is shown from the results of experiments that the proposed method is more useful than adaptive methods with real coefficients.

In this paper, the relationship between the recursive least square (RLS) method with a U-D decomposition algorithm and ARMA lattice filter realization algorithm is presented. Both the RLS method and the lattice filter realization algorithm are used for the same applications, such as model identification, etc., therefore, it is expected that the lattice filter algorithm is in some ways related to the RLS. Though some of the proposed lattice filter algorithms have been derived by the RLS method, they do not express the relationship between RLS snd ARMA lattice filter realization algorithm. In order to describe the relation clearly, a new structure of ARMA lattice filter is proposed. Further, based on the relationship, a method of model identification with frequency weighting (MIFW), which is different from a previous method, is derived. The new MIFW method modifies the lattice parameters which are acquired without a frequency weighting and obtain the parameters of an ARMA model, which is identified with frequency weighting. The proposed MIFW method has the following restrictions: (1) The used frequency weighting is FIR filter with a low order. (2) By using the parameters of the ARMA lattice filter with ARMA (N,M) order and the frequency weighting with L order, the new ARMA parameter with the frequency weignting is with ARMA(N-L,M-L) order. By using the proposed MIFW method, the ARMA parameters estimated with the frequency weighting can be obtained without starting the computation again.

In many applications involving the processing of noisy signals, it is desired to know the noise variance. This paper proposes a new method for estimating the noise variance from the signals of autoregressive (AR) and autoregressive moving-average (ARMA) systems corrupted by additive white noise. The method proposed here uses the low-order Yule-Walker (LOYW) equations and the lattice filter (LF) algorithm for the estimation of noise variance from the noisy output measurements of AR and ARMA systems, respectively. Two techniques are proposed here: iterative technique and recursive one. The accuracy of the methods depends on SNR levels, more specifically on the inherent accuracy of the Yule-Walker and lattice filter methods for signal plus noise system. The estimated noise variance is used for the blind indentification of AR and ARMA systems. Finally, to demonstrate the effectiveness of the method proposed here many numerical results are presented.

A design of an Ada IPC (Inter-Program Communication) interface is proposed, through which a designer of distributed systems can (a) specify arbitrary data types needed for inter-program communication and (b) use parallel programming features to build highly parallel systems; a test simulator was built for execution of the IPC interface and a multi-window system was realized as an application of the interface on the simulator; the interface was found to be useful, making description of inter-program communication simpler and easier.

Control of electronic states of dye molecules (organic semiconductors) by introducing appropriate substituent groups has been examined. NH2 (electron-releasing group) and NO2 (electron-withdrawing group) were introduced in thiacarbocyanine dye to modify the electronic states of the dyes. The effect of modification was examined based on the properties of photoelectric cells made by the dye derivatives. Clear increase in photocurrent, more than ten times, was observed when modified dyes were used instead of the original dye. The result shows that the introduction of substituent groups for organic semiconductors is quite effective to control the electronic states, and the introduction can be regarded as doping in molecular level.

The linear array processor architecture is an important class of interconnection structures that are suitable for VLSI. In this paper we study the problem of mapping a task tree onto a linear array to minimize the total execution time. First, an optimization algorithm is presented for a message scheduling probrem which occurs in the task tree mapping problem. Next, we give a heuristic algorithm for the task tree mapping problem. The algorithm partitions the node set of a task tree into clusters and maps these clusters onto processors. Simulation experiments showed that the proposed algorithm is much more efficient than a conventional algorithm.

This paper introduces some modelling methods of time-varying stochastic process and its linear/nonlinear adaptive identification. Time-varying models are often identified by using a least square criterion. However the criterion should assume a time invariant stochastic model and infinite observed data. In order to adjust these serious different assumptions, some windowing techniques are introduced. Although the windows are usually applied to a batch processing of parameter estimates, all adaptive methods should also consider them at difference point of view. In this paper, two typical windowing techniques are explained into adaptive processing. In addition to the use of windows, time-varying stochastic ARMA models are built with these criterions and windows. By using these criterions and models, this paper explains nonlinear parameter estimation and the property of estimation convergence. On these discussions, some approaches are introduced, i.e., sophisticated stochastic modelling and multi-rate processing.

Truncated sum (TSUM for short) is useful for MV-PLA's realization. This paper introduces a new class of multiple-valued logic functions that are expressed by truncated sum, differential product (DPRODUCT for short), NOT and variables, where TSUM (x, y)min (xy, p1) and DPRODUCT (x, y)max (xy(p1), 0) is newly defined as the product that is derived by applying De Morgan's laws to TSUM. We call the functions T-functios. First, this paper clarifies that a set of T-functions is not a lattice. It clarifies that Lukasiewicz implication can be expressed by TSUM and NOT. It guarantees that a set of p-valued T-functios is not complete but complete with constants. Next, the speculations of the number of T-functions for less than ten radixes are derived. For eleven or more radix p, a speculation of the number of p-valued T-functions is shown. Moreover, it compares the T-functions with B-functions. The B-functions have been defined as the functions expressed by MAX, MIN, NOT and variables. As a result, it shows that a set of T-functions includes a set of B-functions. Finally, an inclusion relation among these functional sets and normality condition is shown.

Many metrics between trees have been proposed. However, there is no research on a graph metric that can be applied to molecular graphs. And most of the reports on tree metrics have dealt with rooted and ordered trees. As the first step defining a graph metric for molecular graphs, this paper proposes a tree metric between unrooted and unordered trees. This metric is based on a mapping between trees that determines a transformation from one tree to another. The metric is the minimum weight among the weights of all possible transformations. The characteristics of the mapping are investigated. A top-down computing method is proposed using the characteristics of the mapping. The time and space complexities are OT(N 2aN 2b(N 3aN 3b)) and Os(N 2aN 2b), respectively, where Na and Nb are the numbers of vertices of the two trees. If the degrees of all vertices of the trees are bounded by a constant, the time complexity of the method is O (N 3aN 3b). The computing time to obtain the distance between a pair of molecular graphs using a computer (SUN SparcStation ELC) is 0.51 seconds on average for all the pairs of 111 molecular graphs that have 12.0 atoms on average. This methic can be applied to the clustering of molecular graphs.

The data-driven model of computation is well suited for flexible and highly parallel simulation of neural networks. First, the operational semantics of data-driven languages preserve the locality and functionality of neural networks, and naturally describe their inherent parallelism. Second, the asynchronous data-driven execution facilitates the implementation of large and scalable multiprocessor systems, which are necessary to obtain considerable degrees of simulation sppedups. In this paper, we present a dynamic data-driven multiprocessor system, and demonstrate its suitability for the paralel simulation of back propagation neural networks. Two parallel implementations are described and evaluated using an image data compression network. The system is scalable, and as a result, the performance improved proportionally with the increase in number of processors.

A 4-way set associative TagRAM with 1.189-Mb capacity has been developed which can handle a secondary cache system of up to 16 Mbytes. A 9-ns cycle operation and clock to Dout of 4.7 ns are achieved by use of circuit techniques such as a pipelined decoding scheme, a single PMOS load BiCMOS main decoder, a BiCMOS sense-amplifying comparator, doubly placed self-timed write circuits, and highly linear VCO for a PLL. The device is successfully implemented with 0.7-µm double polysilicon double-metal BiCMOS technology.