Heat transfer mechanism for the compatible repeater housing, used for coaxial transmission systems, is studied. Temperature rise for the repeater housing and repeater surface is calculated in detail. An efficient improvement plan for the thermal characteristics of the new repeater housing is suggested and confirmed by the experiment.

A new practical parallel garbage collection algorithm and its correctness proof are presented. Some results of its implementation applied to a small size LISP system are reported. The algorithm, which is constructed on the condition that all active lists are bound in the linear stack, needs only one mark bit for each node and a scan-request-flag (SREQ) for the system. The minimum utilization of critical sections, where the operations on SREQ are performed, dispenses with the need for multicolored marking, such as white, gray or black. Also marking efficiency improves since it enables applying a recursive trace-and-mark method instead of a simple scan-and-markmethod. An outline of the correctness proof is as follows : It is proned by induction that the relation, wherein the active-node-set is a subset of the mark-reachable-set, which is defined as the set of all the nodes to which some links exist from any nodes already marked, is retained during the mark propagating phase for any list processing primitives, so that the algorithm guarantees that no active nodes are reclaimed. Last, the implementation of a small size LISP system with this algorithm is reported. The comparison between the parallel system and the regular one is discussed on the basis of actual data.

Optimum inspection schedule is discussed to maximize the availability for a two-unit parallel redundant system when a failure of unit is detected only by actual inspection. The stationary availability is derived by applying Piecewise Markov Process under the assumption that a failure distribution is exponential and other distributions are arbitrary.

Motivated by the pulse train stochastic process in the communication theory, a class of nonstationary linear stochastic processes is defined in terms of the stochastic integral with respect to nonorthogonal random measure. A general form of so called Bennett's formula which had been known only for pulse trains is obtained for the processes, and some concrete examples which sometimes appear in the applied field are given. Weak and strong lows of large numbers for the processes and asymptotic properties of the mean periodogram for them are also discussed in the paper.

This letter briefly introduces the software package SLIP (Subroutine Library for Image Processing) which is a collection of subroutine programs for image processing and pattern recognition. At present, about 340 subroutines of SLIP are available at the Nagoya University Computation Center.

All of the characteristics of the batwing radiator, which is the heart of the super turnstile antenna system, are theoretical calculated by using the Moment Method.

Josephson junctions with semiconductor Te barriers have been studied. First, the junctions were fabricated with the process including oxidation of the evaporated Te film surface. The process was generally employed to avoid shorts through pinholes in Te film. Intensive studies on the influence of the Te barrier thickness and oxidation conditions on the junction characteristic parameters were made. The Te layer acts not only as the barrier for tunneling, that is the normal tunneling resistance shows exponential dependence on the Te layer thickness, but also induces proximity effect at the metal interface. The effect was found to play an important role in the junction performance. It was also found that, in the oxidation process, Te itself is oxidized and the junction performance is largely influenced by the Te oxide layer existance. In the second step, junctions free from oxide layer, which showed Josephson effect up to the Te barrier thickness of 40 nm, have been fabricated. By employing smooth surfaced Nb bottom electrode as well as the photolithographic technique comprising the trimming process, uniform junctions perfectly free from pinhole shorts have been realized.

Electric potentials associated with surface acoustic waves (SAW) and bulk waves on free surfaces of crystals have been computed. Compiled are data for LiNbO3, LiTaO3 and quartz with rotated Y-cut X-propagation and X-cut rotated Y-propagation. As a result, it is shown that for certain cuts of crystals bulk waves are hardly generated by interdigital transducers (IDT).

Linear array antennas weighted by selective withdrawal of elements have been optimized for sidelobe reduction. The optimization was carried out for antennas with total elements up to 41 by modifying implicit enumeration algorithm for 0-1 type integer optimization. Results obtained, for example, show that the sidelobe level optimized decreases almost monotonically with an increase in the total number of elements, and that the sidelobe level of about 19.0 dB is obtainable for the antenna with total elements of 41.

We consider an initial value problem of the K-dV equation. The initial function is, in our case, assumed to be periodic with respect to the x-coordinate. Such a periodic function is inserted as the potential function in the associated Schrödlinger equation. The equation is, therefore, of Hill's type. A stable region in the stability chart in the λ-A plane for Hill's equation corresponds to a band which consists of continuous eigenvalues, were A is the amplitude of the periodic function and λ the eigenvalue. As the potential function, we consider a function in which dips of cosine functions of one-period stand side by with constant interval. When the interval between two consecutive cosine pulses is made infinite, the eigenvalues for one potential of cosine type is obtained. In this limiting case, clear correspondence between the numbers of eigenvalues and solitons is obtained, and soliton regions are precisely determined. This analysis can be compared with results of computer experiments on the K-dV equation. On basis of our method, it is seen that the determination of soliton region is also usable for the determination of the number of solitons.

This paper describes the algorithm and convergence properties of an adaptive echo canceller with linear predictor. Conventional echo cancellers based on the learning identification algorithm may not provide good performance, because the rate of convergence is low due to the high correlation of speech signals, and echoes at the beginning of calls cannot be cancelled. In order to obtain better convergence properties, the new echo canceller adopts a linear prediction as the method for decorrelating the speech signals. The identification of the echo path and the generation of the echo replica are conducted independently, and the identification of echo path is carried out with prediction errors of speech signals and echo signal when predictor coefficients are decided by the linear prediction of speech signals. The echo replica is generated by putting the received speech signal through the echo path model. Computer simulation has shown that the new echo canceller is converged faster than conventional echo cancellers and that the convergence properties are better as the degree of linear prediction is higher and the predictor coefficients are more accurate. In case the degree is five, the rate of convergence is about twice as high and Echo Return Loss Enhancement (ERLE) increases over 10 dB in comparison with the conventional one.

Properties of current gain variation in n+ -p -n -n+ power transistors preceding to the thermal mode second breakdown and their applications to evaluate the resistance of second breakdown are presented. The characteristics of current gain in power transistors with junction temperature and current density are examined under high voltage operating conditions which are sufficient to generate thermal instabilities and second breakdown. Applying these properties, processes of generation of thermal instabilities and second breakdown in power transistors are investigated. Predictions of second breakdown initiation are made by monitoring the variation of the base current under the constant voltage and constant current conditions at the collector-base junction. The waveforms of the base current under these conditions show the typical changing point just before the second breakdown initiation. It is concluded that, the characteristic phenomena are related to the variation of the current gain, and the changing point corresponds to the generation of thermal instabilities. The forward biased second breakdown resistance can be measured without damage or degradation of the sample transistors, if the supplied power has been removed when the base current reaches the changing point.

First, in this paper, a new type of interactive optimization method for multiobjective optimization problems is suggested. The method is made up with the calculation phase to generate a tradeoff curve from the Pareto optimal solution set and the decision phase to choose a preferable point on the curve. And these phases are alternated each other and a final preference solution is found eventually. Next, the method is applied to an optimal control problem of multipurpose dam where the storage water can be supplied for five use purposes, i.e. hydroglectric power generation, industrial, agricultural, municipal and adjustment water. The application results are compared with some specific cases and the effectiveness of the method is proved.

This paper gives an analytical method to determine the existence of the long period mode which is the most typical rhythmic activity in reciprocal inhibition networks. The network is assumed to have a considerable odd number of neurons in a ring structure of a linear array. In the long period mode, each cell has the active and the quiescent phases. A number of firings are seen at the constant interval in the active phase, while the firings are inhibited in the quiescent phase. It is shown that there exist many firing patterns in this mode, and that the period length of the rhythmic activities is different depending on the number of firings in the active phases. The upper bound of the period length increases with the increase of the number of cells. Since various firing patterns are possible to occur under identical input and structure parameters, occurrence of each firing pattern of the long period mode has to be determined by a suitable selection of initial conditions of the network. Relations between the firing patterns and the initial conditions are studied in terms of phase transition delay time.

Large-signal analysis of an IMPATT diode is presented, where the effect of harmonic-frequency circuits is included. The particle current and the AC voltage in a diode are expanded into Fourier series, and their harmonic components are related with each other by the corresponding impedances of the harmonic-frequency circuits. The numerical results show that the oscillation power of the IMPATT diode is considerably increased by the appropriate choice of the harmonic-frequency circuits. The theoretical model is also applied to an actual IMPATT oscillator. The oscillation characteristics of the circuit is clarified by the numerical calculations, and the results are almost in good agreement with the experiment.

Frequency characteristics of SAW tapped delay lines (TDL's) with equal tap spacing and in-line array are investigated. It is found that reflected SAW echo signals in SAW TLD's cause pulse-like ripples and sharp stopband distortions periodically in the frequency passbands. Tapping design techniques are proposed to remove spurious interference distortion influences on SAW TDL frequency responses. Their applicability is confirmed experimentally. Typical features of a SAW TDL with 101 taps at a 20 MHz bit rate employing 128 rotated Y-cut and X-propagation LiNbO3 substrate are as follows: center frequency is 55.4 MHz, frequency bandwidth is 10 MHz, insertion losses are 3239 dB, and ripples in the passband are about 4 dB.

We report a magneto-optic bistable device using a magnetic thin film waveguide modulator. Because of a discontinuous transmission curve of this waveguide, optical bistable operations can be obtained with a wide range of bias field at room temperature.

This paper describes an experimental investigation on the phase constant and the cutoff wavelength of a cocoon-section corrugated waveguide (CCWG) with a cocoon-cross-section configuration and a sinusoidal-wave helical corrugation along the longitudinal axis at guide-walls. The CCWG is widely used for antenna feeder waveguides of the 4, 5, 6 and 7 GHz-band microwave communication systems. The purpose of this investigation is to get a useful means for an easy design of the corrugated waveguide. We have measured resonance frequencies of cavities made of 4, 6 and 7 GHz-band CCWGs at frequencies between 3 and 8 GHz by means of a resonant cavity method. As an example of results, the measured phase constant of the 4 GHz-band CCWG is a few percents larger at the frequency range 3.64.2 GHz than the calculated one of a cocoon-section smooth waveguide (CSWG) with a tube diameter equivalent to the center diameter of corrugated guide-walls. And the measured cutoff wavelength is nearly equal to the calculated value of the CSWG. As a result of this investigation, the experimental equation showing a dispersive property of the phase constant of the CCWG is led assuming that the corrugation size is small as compared with the major diameter.

A wafer type point-contact Josephson junction to be inserted into the waveguide WRJ-900 after adjustment at room temperature has been developed, and used for the detection of 102 and 200 GHz waves. The voltage responsivity of this detector was 4.8104 V/W at 102 GHz and 1.0104 V/W at 200 GHz. For the frequency response of the junction, Shapiro steps up to about 2 THz were observed.

The temperature-stable surface acoustic wave substrate consist of the ZnO/Pyrex glass is described. This substrate has the zero first-order temperature coefficient of the frequency, the very little phase velocity dispersion and the relatively high piezoelectric coupling constant. The raw material cost is also very low. We applied this substrate to the surface acoustic wave T.V. IF filter, and some excellent qualities were obtained.