An extraction method of density contour lines of gray level pictures is described. Two kinds of quads composed of four image pixels and non-image pixels are defined for making the density contour lines simple closed paths. From the resultant density contour lines of simple closed paths, a tree graph is made for executing the recognition of a house included in a monochromatic aerial photo of an urban area.

Using an integrated optical circuit, a new device for Two-Dimensional (2-D) Walsh transforming is proposed. The feature is that both the wiring line and adder circuit in conventional devices are replaced with one crossing point of two optical fibers. A light signal is injected into the input terminals, the addition on the way is performed by light, and the subtraction is carried out in the last stage.

Fourier reconstruction has orginally been one of the methods for three-dimensional structure reconstruction in medical applications such as the computed tomography (CT). The technique is found to be applicable to designing circularly symmetric FIR digital filters. The algorithm is simple, straightforward and practical. The approach basically consists of designing a one-dimensional (1-D) FIR prototype, rotating its frequency response in the two-dimensional (2-D) frequency plane, inverse Fourier transforming and then windowing the result. An unlimited number of profections at different orientations of the obtained impulse response are essentially identical with the 1-D FIR prototype. The even size 2-D FIR filters can also be designed. The impulse response has eightfold (octagonal) symmetry. The frequency response is shown to have nearly circular symmetry that is evaluated with rms and maximum absolute errors.

This letter predicts that multichannel SAW filters can be constructed by using two dimensionally periodic reflective dot array (RDA). A three channel device, where one channel is with direct SAW propagation path and the others are with offset SAW propagation pathes, was constructed for experimental verification.

Behavior of the longitudinal mode is analyzed for injection laser with undoped active region. Injection laser shows multi-longitudinal-mode-operation at near the threshold current level, and becomes to single-longitudinal-mode-operation with increasing of the injection current beyond the threshold current level, due to strong suppression effect among the longitudinal modes. Such behavior is analyzed quantitatively for AlGaAs DH laser with consideration of some factors such as mixing of the spontaneous emission, carrier diffusion, threshold current level and field profile. The single-longitudinal-mode-operation is achieved in lower injection level with smaller spontaneous emission factor, lager effect of the carrier diffusion, lower threshold current level and transverse-fundamental-mode.

In this paper we study the problem of recognizing connectedness of three-dimensional patterns. We investigate the upper and lower bounds of space complexity for this problem. These results are compared with two-dimensional case. It reveals that recognizing three-dimensional connectedness is much more difficult than two-dimensional case. We introduce a three-dimensional k-marker automaton (MA(k)) and a three-dimensional S(n) space-bounded Turing machine (TM(S(n))). We prove that a nondeterministic MA(1), a nondeterministic TM(log n) and a deterministic TM((log n)2) can accept connected patterns. We also prove that a deterministic TM((log n)2) can accept patterns of k connected components (k is a constant). Next, a three-dimensional five-way S(n) space-bounded Turing machine (5WTM(S(n))) is introduced. It is a restricted model of TM(S(n)) whose input head can move north, south, east, west and down, but not up. We prove that the space n2 log n is necessary and sufficient amount for a deterministic 5WTM(S(n)) to recognize connected patterns.

A modified spiral antenna termed a "sunflower spiral antenna" which consists of smooth section and zigzag section is proposed to improve the axial ratio. The analysis of the current distribution along the arm is carried out by an integral equation method. It is revealed that the zigzag section of the sunflower spiral considerably contributes to the suppression of standing wave near the arm end, especially at lower frequencies after the establishment of the first mode radiation in terms of current band theory. It can be emphasized that the sunflower spiral achieves a wide band characteristic of the axial ratio without deteriorating inherent radiation pattern, power gain and input impedance of a conventional round spiral antenna.

The optimization, in the minimax sense, of an endfire array antenna with constraints on side lobes over a certain region and the Q-factor is presented for variable amplitude and phase excitation. The technique employed consists of the combination of an augmented Lagrangian algorithm and a direct search method of optimization. The problem with constraints on only side lobes, and the one with constraints on side lobes and the Q-factor have been solved for a 0.4 λ spaced linear array of 10 isotropic elements, and the amplitude and phase required to achieve optimal directivity are determined. These results are illustrated and compared with the optimum case without any constraint and the one with constraint on only the Q-factor. Also, the optimal directivity is shown for various specified side lobe levels.

The present paper is concerned with the application of microwave thermography to the estimation of temperature profiles inside a human body. The aims of the study are to propose a basic idea of the method of measurement which enables one to estimate the temperature profiles from the measured brightness temperatures, and to design a new radiometer that is suitable for the specific measurement of the brightness. To this end, we reviewed the dielectric properties of biological media. By adopting those properties, a mathematical model of a human tissue was made in order to take a general view of radiation from the body. Based on the results of those theoretical investigations we designed a Dicke-switched superheterodyne multifrequency radiometer equiped with five radiometric frequencies, 1.0, 1.7, 2.8, 4.6 and 10 GHz. The numerical inversion techniques required to estimate the temperature profiles from the measured brightness temperatures were also discussed. The new method of measurement is expected to have a good potential for detecting and localizing subcutaneous thermal abnormalities.

We derived the optimum receiver structure for an M-ary PSK signal in the presence of Gaussian noise and a single sinusoidal (CW) interfere. And by computer simulation we confirmed that the derived optimum receiver performs better than the standard receiver (which is optimum only to Gaussian noise) in the interference environment.

A fundamental method of producing scan animations by a digital computer is described by taking motion trajectories and lengths of light trails of objects as parameters, and examples of scan animation are illustrated.

The new profile-control technique was investigated in regard to the modified CVD method to reduce OH-ion concentration in GeO2-P2O5-doped silica graded-index optical fibers. The new profile-control technique, in which only exygen flow rate is varied for a parabolic radial index profile, was successfully attained by utilizing effects of exygen on properties of the deposited glass layer. Amounts of GeCl4 gases, which do not react with oxygen, exist in the heated zone of a supporting tube and can effectively eliminate H2O contaminations by the new profile-control technique. A GeO2-P2O5-doped silica graded-index optical fiber was obtained, that simultaneously has a high transmission bandwidth of 1.5 GHzkm and OH-ion absorption loss of 0.9 dB/km at 1.39 µm.

In instructional design, designers (or teachers) choose an optimum educational media (or educational system) adaptive to the learners' abilities. Although instructional design has been recognized as one of the important teachers' activities thus far, they left most of it to their individual subjectives. In order to perform the design in an objective way, a new mathematical method is proposed here to discriminate if the concerned educational system will be effective to learners on not. It is based on the use of linear discriminant analysis. However, when we apply it to the discrimination on education, the conventional method is not always appropriate to the field of education because many educational events are fuzzy, thus it requires refinement. From the point that the author regards the fuzziness proper to education, in order to aid teachers' instructional designing in an objective way, this paper presents a new logic which fixes linear discriminant function, the equations of error probability and Maharanobis' Generalized Distance considering the fuzziness.

Bit error rate (BER) performance of convolutional coding/soft decision Viterbi decoding is investigated theoretically. Firstly, equations are derived to calculate the tight upper bound of the BER performance for the multi-level soft decision with arbitrary threshold spacing, considering the quantized metric used in the Viterbi decoder. Experimental results on the BER performance of a rate 1/2 code with constraint length 7 are shown to demonstrate that the derived equations provide the precise BER performance. Then, the BER performance of various codes is calculated for 4- and 8-level soft decision as well as hard decision and ideal (infinite level) soft decision. The codes examined in this paper cover typical codes with 64 states of rate 1/4 through 3/4 and the rate 1/2 codes with constraint length 3 through 14. From the BER curves obtained for these codes, the coding gain is clarified as a function of coding rate and code constraint length. Main results obtained in this paper are as follows. (1) Among codes with 64 states, rate 1/3 code gives the maximum coding gain. (2) Coding gain of a rate 1/2 code increases as constraint length K becomes large. In the case of 8-level soft decision, for instance, the coding gain of the code with K14 reaches 7.1 dB at BER10-6, which is close to the maximum coding gain obtained by an infinite constraint length code (estimated to be 7.9 dB).

The algorithm for the fast Walsh-Hadamard transform (FWT) derived from the Walsh-Paley function provides fast and simple processors which calculate the i-th Walsh transform Fi (i0, 1, , 2n1) of the natural-, dyadic-, and sequency-ordered Walsh-Hadamard transforms respectively according to control signals. This processor needs only 22n1 adder-subtractors (A/S) and is n times as fast as the one of the iterative type with n iterations. The characteristics of FWT with the term T resemble that of the assembly of digital filters. The digital filter representing FWT can be analyzed with z-transform and its transfer function is described as a simple function of z. The 3 dB bandwidth calculated by FWT is almost constant (about 0.85/T) for n2, 3, ...,10. All the Walsh transform Fi can be calculated by the processor with n2n A/S, while the processor using delay lines needs only 22n1 A/S. The improved processor with delay lines deals with successive data and calculates all the Walsh transform or the Walsh spectrograms at the same time. These processors are effective for the recognition of speech and the analysis of signals.

An improved numerical solution method for Bayesian estimation in nonlinear image restoration is presented. The constraint condition for the previous Bayesian method is also derived only in a simplest case. This method are shown to be more practical than the previous restoration methods.

This letter presents experimentally that the power gain of axial-mode helical antenna can be improved by installing a relatively thin dielectric cylinder outside the helix, and also presented in some theoretical consideration to clarify the above effect approximately.

A nonlinear model of the basilar membrane (BM) is examined for the two-tone suppression (TTS). The authors tested the BM displacement, velocity and acceleration as a possible candidate of the stimulus to the hair cell. Only in the BM acceleration TTS was observed, that has quite similar tendencies to physiological data.

In digital satellite communication systems, the high power amplifier (HPA) in the satellite repeater and earth station should operate in the vicinity of the saturation point, in order to effectively use output power. Recently, the adoption of constant envelope modulation schemes, like minimum-shift-keying (MSK) and MSK-type modulation (i.e. modified MSK), have been considered to avoid nonlinear harmful influence. This paper describes a new MSK-type modulation scheme, called Gaussian filtered and amplitude limited MSK (GLMSK). The idea behind GLMSK is to remove the envelope variations of the filtered MSK at the modulator by using a limiter with a small AM-PM conversion coefficient. GLMSK performance is calculated and estimated on some parameters, and the implemented GLMSK modem operation and performance are shown at a nominal data transmission rate of a 100 Mbit/s and an intermediate frequency of 1.7 GHz. Constant envelope GLMSK with a narrow spectral band can be achieved by using conventional high-speed MSK modem techniques.

The discrete Josephson junction transmission line which has N series Josephson junctions in each loop is discussed by computer simulation. It is found that a single quantum in this line can be stuffed in about one loop even if the inductance of each loop decreases to be negligibly small, i.e., the contribution of flux to a fluxoid is decreased. In this line the very small size fluxoid quanta with little flux can be employed as information bits. The resistive Josephson transmission lines whose loops have resistances in series are also discussed. In the resistive lines various operations are possible because of relaxation of the quantization conditions.