Spoken language systems such as speech-to-speech dialog translation systems have been gaining more attention in recent years. These systems require full integration of speech recognition and natural language understanding. This paper presents an efficient parsing algorithm that integrates the search problems of speech processing and language processing. The parsing algorithm we propose here is regarded as an extension of the finite-state-network directed, one-pass search algorithm to one directed by a context-free grammar with retention of the time-synchronous procedure. The extended search algorithm is used to find approximately globally optimal sentence hypotheses; it does not have overhead which exists in, for example, hierarchical systems based on the lattice parsing approach. The computational complexity of this search algorithm is proportional to the length of the input speech. As the search process in the speech recognition can directly take account of the predictive information in the sentence parsing, this framework can be extended to sopken language systems which deal with dynamically varying constraints in dialogue situations.

Syntax-directed editors have several advantages in editing programs because programming is guided by the syntax and free from syntax errors. Nevertheless, they are less popular than text editiors. One of the reason is that they force a priori specified editing structures on the user and do not allow him to use his own structure. ACE (Algorithmically Customizable syntax-directed Editor) provides a solution for this problem by using a technique of machine learning; ACE has a special function of customizing the grammar algorithmically and interactively based on the learning method for grammars from examples and queries. The grammar used in the editor is customized through interaction with the user so that the user can edit his program in a more familiar structure. The customizing function has been implemented based on the methods for learning of context-free grammars from structural examples, for which the correctness and the efficiency are proved formally. This guarantees the soundness and the efficiency of customization. Furthermore, ACE can be used as an algorithmic and interactive tool to design grammars, which is required for several purposes such as compiler design and pretty-printer design.

In general, a two-dimensional display is defined by two orthogonal unit vectors. In developing the display, discriminant analysis has a shortcoming that the extracted axes are not orthogonal in general. First, in order to overcome the shortcoming, we propose discriminant analysis which provides an orthonormal system in the transformed space. The transformation preserves the discriminatory ability in terms of the Fisher criterion. Second, we present a necessary and sufficient condition that discriminant analysis in the original space provides an orthonormal system. Finally, we investigate the relationship between orthogonal discriminant analysis and the Karhunen-Loeve expansion in the original space.

Hydrogen termination of HF-treated Si surfaces and the oxidation kinetics have been studied by x-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR) Attenuated Total Reflection (ATR). The oxidation of hydrogen-terminated Si in air or in pure water proceeds parallel to the surface presumably from step edges, resulting in the layer-by-layer oxidation. The oxide gryowth rate on an Si(100) surface is faster than (110) and (111) when the wafer is stored in pure water. This is interpreted in terms of the steric hindrance against molecular oxygen penetration throughth the (110) and (111) surfaces where the atom void size is equal to or smaller than O2 molecule. The oxide growth rate in pure water for heavily doped n-type Si is significantly high compared to that of heavily doped p-type Si. This is explained by the conduction electron tunneling from Si to absorbed O2 molecule to form the O2- state. O2- ions easily decompose and induce the surface electric field, enhancing the oxidation rate. It is found that the oxidation of heavily doped n-type Si in pure water is effectively suppressed by adding a small amount (1003600 ppm) of HCl.

We introduce new computer algorithm of multiple alignment as an application of "Simulated Annealing" method. Simulated Annealing has been applied to some combinational optimization problems such as travelling salesman problem. After giving short mathematical explanation of this method, we construct genetic distance and matrix corresponding to the object function in the annealing theory for the multiple alignment. Our method is better than other alignment in the sense that we obtain a result having a smaller value for the genetic distance. We discuss further development along on new method.

An intermediate-frequency-combining (IF-combining) polarization diversity using frequency conversion is proposed. The proposed diversity requires no phase controller as opposed to the conventional IF-combining diversity. It has been theoretically clarified that this diversity has polarization insensitive bit-error-rate (BER) characteristics. The effectiveness has been confirmed by experiments in which the sensitivity dependence on the polarization is suppressed to within 0.8dB and a stable 101km fiber transmission at 600Mbit/s is achieved.

This paper analyzes the performance of the capacity controlled digital radio system, which controls the number of modulation levels according to the amount of traffic. These analyses are performed under thermal noise and co-channel interference. As a result, the throughput improvement is approximately 16 times comparing with the fixed capacity system which has the designed outage probability of 0.1%. Theoretical results are applied to the future mobile communication system which utilizes TDMA access method or burst co-dec, and it is found that the reuse distance can be improved to 1/5 times when the designed outage probability is 0.1%.

An extremely accurate and very wide-band quadrature modulator IC fabricated on a single chip using bipolar technology is presented. The characteristics of this quadrature modulator IC are much superior to conventional ones (modulation phase error and deviation from quadrature is about 1/10), and this IC is applicable to high modulation schemes such as 256 QAM. In this circuit, the phase difference between local signals input to each of two balanced modulators is detected by a phase detector, and a variable phase shifter in the local port is controlled automatically by the detected signals. This, along with the use of a wide-band variable phase shifter, enables the phase difference between the local signals input to the balanced modulators to be adaptively controlled to 90 degrees in wide frequency bands. In addition, a design method for the balanced modulators to obtain small modulation phase error is described. Based on this design method, a highly accurate quadrature modulator IC was fabricated, in which two balanced modulators, the phase detector, and the variable phase shifter were integrated on a single chip. Phase deviation from quadrature in the local signals was reduced to less than 0.3 degrees in the wide frequency bands of more tham 60 MHz. The modulation phase error of the balanced modulators wes less than 0.2 degrees at 140 MHz, and less than 2.5 degrees at up to 1.3 GHz.

This paper discusses and evaluates, from the viewpoints of definition, analysis, and performance, frequency assignment schemes that enable the efficient assignment of multiple-bandwidth carriers on the transponder in SCPC/FDMA systems with demand assignment operation. The system considered handles carriers of two different bandwidths, and assigns only consecutive slots on the transponder band to broadband carriers. Three types of frequency assignment schemes are proposed, each of which incorporates one or both of two assignment concepts: (1) pre-establishment of assignment priorities on the transponder band, and (2) establishment of broadband slots to guide broadband carrier assignment. Following a definition of the schemes, equations are derived to theoretically analyze performance factors such as call loss for the narrowband and broadband carriers, and system utilization efficiency. Finally, theoretical performance calculated for various traffic and system conditions are presented and evaluated, for the purpose of comparison between the three schemes. Computer simulation results are also presented, to demonstrate the accuracy of the derived equations and to supply data for models too large for theoretical computation. Main results obtained are as follows. (1) Regardless of traffic or system conditions, the assignment scheme incorporating both assignment priorities and broadband slots shows the best performance in terms of broadband call loss and system utilization efficiency. (2) The establishment of broadband slots improves performance when the ratio of broadband traffic to the total traffic volume is high, but worsens performance when the narrowband traffic ratio is higher. (3) All aspects of performance improve with the increase of the total number of assignable slots on the transponder band.

The optimal coding strategy for signal detection in the correlated gaussian noise is established for the distributed sensors system with essentially zero transmission rate constraint. Specifically, we are able to obtain the same performance as in the situation of no restriction on rate from each sensor terminal to the fusion center. This simple result contrasts with the previous ad hoc studies containing many unnatural assumptions such as the independence of noises contaminating received signal at each sensor. For the design of optimal coder, we can use the classical Levinson-Wiggins-Robinson fast algorithm for block Toeplitz matrix to evaluate the necessary weight vector for the maximum-likelihood detection.

In this paper, voltage-input current-output Membership Function Circuit (MFC) and Normalization Locked Loop (NLL) are proposed. They are useful building blocks for the current-mode analog fuzzy hardware. The voltage-input current-output MFC consists of one source coupled type Operational Transconductance Amplifier (OTA). The MFC is used in the input parts of the analog fuzzy hardware system. The fuzzy hardware system can execute the singleton fuzzy control algorithm. In the algorithm, the weighted average operation is processed. When the weighted average operation is directly realized by analog circuits, a divider must be implemented. Here, the NLL circuit, which can process the weighted average operation without the divider, is implemented using one source coupled type OTA. The proposed circuits were designed by using 2 µm CMOS design rules and its operations were confirmed using SPICE simulations.

An integrated CAD/CAM system for MMIC development has been firstly realized, which consists of electron beam direct drawing, microwave circuit simulator, pattern generator and RF &DC on-wafer automatic measurement subsystems, connected through an Ethernet LAN. The system can develop not only new MMICs and their element devices, but also their accurate simulation models quickly and efficiently. Preliminary successful applications of this system have been demonstrated by DC-HFET with a 0.25 µm T-shaped gate electrode and MMIC low-noise amplifiers operating at X- and L-bands.

A fast scan-line algorithm for a raster-scan graphics display is proposed based on an observation that a sequence of successive image frames in animation mostly consists of still objects with relatively few moving objects. In the proposed algorithm, successive images are generated using the background image composed of still objects only, and moving image composed only of moving objects. The color of each pixel in the successive images is then determined by one, which is nearer from eye, between the two candidate pixels, where one is from the background image and the other is from the moving image. The background image is generated once in the whole process, while the moving image is generated for each time frame using an interpolation of two images generated at the start and end time of the given time interval. For the purpose of fast shadow generation, we classify the shadows into three groups, i.e., still shadows generated by still objects on still objects, moving shadows generated by moving objects on still objects, and composite shadows generated by both still objects and moving objects on moving objects. These shadows can be generated very quickly by utilizing the frame coherence. According to the experimental results, a speed up factor of 3.2 to 12.8, depending on the percentage of the moving objects among all objects, was obtained using our algorithm, compared to the conventional scheme not utilizing the frame-to-frame image coherence.

General estimation technique using covariance information is proposed for white Gaussian and white Gaussian plus coloured observation noises in linear stationary stochastic systems. Namely, autocovariance data of signal and coloured noise appear in a semi-degenerate kernel, which represents functional expression of the autocovariance data, in the current technique. Then the signal is estimated by directly using autocovariance data of signal and coloured noise. On the other hand, in the previous technique, the covariance information is expressed in the form of a semi-degenerate kernel, but its elements do not include any autocovariance data.

The F-matrix expressions of inverted-L-type four-terminal networks, each involving an element with the power-law conductivity σ(ω)ωa (0a1) connected to a resistance R, an inductance L or a capacitance C, were derived using the standard procedures of Laplace transformation, indicating that the exponents of the complex angular frequency s, so far limited to the integers for the transmission circuits with finite elements, can be extended to the real numbers. The responses to a step voltage calculated show hysteretic behavior reflecting the resistance-capacitance ambivalent nature of the power-law conductivity.

Novel transmission line structures for multilayer MMICs, which are constructed with thin dielectric layers on a GaAs wafer surface, are theoretically and experimentally investigated. Five thin film transmission line structures are discussed in this paper: (1) Microstrip lines, (2) Inverted microstrip lines, (3) Triplate lines, (4) Trapezoidal microstrip lines and (5) Valley microstrip lines. These transmission line structures are fabricated using thin polyimide films and chemical etching.

Novel, very small-size multilayer MMIC's using miniature microstrip lines on a thin dielectric film, as well as the features of the multilayer structure, are presented. Very narrow-width thin-film transmission lines, meander-like configurations, line crossovers, and vertical connections, which are effective for significant chip-size reduction and flexible layout, are realized and utilized in a 2.5-3 µmN-layer dielectric film structure. 180-degree and 90-degree hybrids and umltiport Wilkinson dividers, which are implemented in small areas of 0.1 mm2 and 1.7 mm2, are presented. Furthermore, layout flexibility in the multilayer structure is demonstrated by implementing distributed amplifiers into the layers.

This paper describes the design of a 38-GHz high power MMIC amplifier using an improved load-pull technique. We improved the load-pull technique accuracy by using MMIC transtormers to match the input and output impedances of a GaAs MESFET to about 50 ohms. We used this technique to measure the large-signal load impedance of a FET with a 600-µm-wide gate. Using the data obtained, we developed an MMIC amplifier composed of two of these FET cells. At 38 GHz, the amplifier has an output power of 23.5 dBm for a 1 dB gain compression level.

This paper proposes parallel VLSI processors for robotics based on multiple processing elements organized around multiple bus interconnection networks. The advantages of multiple bus interconnection networks are generality, simplicity of implementation and capability of parallel communications between processing elements, therefore it is considered to be suitable for parallel VLSI systems. We also propose the optimal scheduling formulated in an integer programming problem to minimize the delay time of the parallel VLSI processors.

A type of infinite dimensional homotopy method is considered for numerically calculating a solution curve of a nonlinear functional equation being a Fredholm operator with index 1 and an A-proper operator. In this method, a property of so-called A-proper homotopy plays an important role.