Industrial products usually involve initial failure type components. It is most important to remove initial failure products by screening after aging. Considering constant delivery products with a long average life time, both initial failure type and the repair system, we shall find that soon after initial delivery the number repaired exceeds the number produced. We call this point the maintenance deffect point". To solve this problem, it is effective to remove initial failure products by screening after aging. The aging effect is calculated under the assumption that failure occurs according to the Weibull distribution. In the case where aging time is normalized by using time, the effect becomes similar to the effect calculated under the assumption of the non-repair system. In this case, the total cost consists of failure cost and aging cost. By using the aging effect to calculate failure cost, we find that the aging time for minimum total cost in a macroscopic view is almost independent of both the shape parameter m and the accelerating factor α. It does depend, however, on the cost ratio, which is the ratio of the aging cost limit to the repair cost limit at no aging. This result is useful in programming both aging space and electric power for aging at the time of plant construction. This programming results in highly reliable products.

A technique is described to compensate the difference between lateral magnifications in ellipso-interferometry with tilted image plane by using an optical fiber bundle having an obliquely cut and polished end. A major limitation of this technique also presented.

The method of improvement on the polarization property of a turnstile spherical array antenna is proposed and its numerical results are discussed. It is found that the spherical array becomes capable of scanning its beam up to large angle with circular polarization through the improvement.

A new type of highly stabilized feedback oscillator has been developed, consisting of a balanced GaAs FET amplifier and an independent band-pass filter comprising a dielectric resonator. This paper describes fundamental properties of this oscillator at microwave frequencies and experimental results for the newly proposed feedback oscillator with a balanced amplifier (balanced-type" feedback oscillator), comparing it with a feedback oscillator using a single amplifier (single-type" feedback oscillator). The balanced-type oscillator suppresses frequency variation due to changes in S11 and S22 of the GaAs FETs. Experimental results in the 5-GHz band show that frequency stability of the balanced-type oscillator is superior to that of the single-type oscillator. Based on the above results, a balanced-type feedback oscillator in the 14-GHz band is demonstrated. As a result, an oscillator with a frequency stability of less than 1105 over a temperature range from 5 to 45, nearly equal to the frequency stability of a microwave source using a crystal oscillator, and an output power of 17 dBm at 13.5 GHz has been realized.

The great technological progress in very large scale integration (VLSI) of electronic circuits has made it possible to implement a large distributed computing system on a single VLSI chip. Distributed algorithms suited for VLSI implementation are generally called 'VLSI algorithms', and many VLSI algorithms have been devised for solving several kinds of problems. This paper discusses a VLSI algorithm for pattern matching. We propose a new VLSI-oriented pattern matching algorithm in which regular expressions are adopted to represent a pattern. The proposed algorithm will be implemented on a configurable multi-processor system, which can dynamically change its interconnections among the processors according to the external inputs. Thus the pattern may be arbitrarily changed after the chip fabrication. We call such an algorithm the 'programmable' pattern matching machine (PPM for short). The programmability makes it possible for PPM to have wide applications which the previously known algorithms could hardly have. PPM consists of n(n1)/2 processors, where n is the length of a pattern, and can recognize a string of length m in m (independent of n) clock periods. PPM also has preferable properties, such as a regular structure and a simple control mechanism, for VLSI implementation.

An electroretinogram (ERG), which shows output characteristic of retina, is useful in the clinical aspect. Then, we have constructed an electronic model to simulate a scotopic human ERG considering physiological observations.

Multipath fading is often serious in radio communications. It is possible to reduce the multipath fading by using an LMS adaptive array. This letter describes the behaviors of the LMS adaptive array in the presence of correlated multipath signals.

This paper describes an error-correcting parser for a context-free language based on the Graham-Harrison-Ruzzo's context-free recognizer (GHR). The parser has similar characteristics as GHR:(1) The parser unifies both the top-down error-correcting parser by Lyon and the bottom-up error-correcting parsers by Tanaka-Fu and Yamasaki-Tonomura.(2) The parser is conceptually simpler than the Lyon's parser, and may be much faster than the bottom-up error-correcting parsers.

AN codes are effective for the error correction in the arithmetic operations using the symmetric r-ary number representation (SrR). This paper discusses the existence of perfect AN codes in SrR and shows that such codes exist for r3, 5, 7, 11 but do not for r9. Furthermore, it is shown that there exist near perfect AN codes in SrR similar to Neumann-Rao AN codes in the conventional r-ary number representation.

The behavior of simultaneous asynchronous oscillation in an oscillator consisting of an idler circuit, two resonant circuits and a cubic nonlinear element, is investigated experimentally.

Reachability of marked graphs with token capacity constraints is generalized to that with respect to any subgraph of the marked graph. It is shown that submarking reachability is equivalent to the existence of a minimum firing count vector satisfying a set of equality and inequality constraints. A necessary and sufficient condition is presented for the existence of the minimum firing count vector together with its constructing algorithm. The result can be applied in finding the firing sequence of minimum length in practical sequential control problems.

We construct an efficient decoder for single and double error correcting-triple error detecting BCH codes by adding a simple error identifying circuit to the decoder for double error correcting BCH codes.

A new type of Josephson NDRO memory cell is presented, where a sense gate is coupled directly to the memory part, instead of the conventional magnetic coupling scheme. The memory cell operates without complexity of the sequence of signals, and the operation margin is shown to be 20%.

This paper describes Japanese-English translation of weather reports by ISOBAR. Recently, there have been developed a lot of automatic translation systems, either operational or experimental. In the domain of meteorological reports, TAUM-METEO (English-French) is the best-known operational system, which is classified as one of the transfer systems. Our translation by ISOBAR is still experimental, but its most remarkable feature is that target language (TL) sentences are generated only from interlingual meaning representations of input source language (SL) sentences. That is, our system has no transfer component. In this approach, one sentence can be translated into plural TL sentences which are in the paraphrase relation. During semantic processing of SL sentences, ISOBAR, unlike Wilks' model, is designed to reject definitely such sentences as are semantically anomalous or contradictory to its knowledge. We discuss several merits and demerits of this approach, and show some experimental results in ISOBAR.

A new method of exciting a two-wire spiral antenna from two off-center sources is proposed in order to obtain the polarization diversity. It is found both numerically and experimentally that as the locations of two sources are shifted from the center of the spiral towards the arm ends, the radiation wave changes from a right-hand to a left-hand circularly polarized wave, by way of a stage in which a linearly polarized wave is produced. On the basis of the obtained results, the frequency characteristics of a spiral antenna with two fixed sources are investigated. It is found that the spiral antenna radiates a right-hand circularly polarized wave at a frequency of f" and a left-hand circularly polarized wave at a frequency of 2f".

Excitation amplitude and phase coefficients of array elements are designed for the use of a primary feed reflector antenna with the intension of improving its beam scanning characteristics. Special attention is paid for beam isolation between two adjacent beams in an area coverage beam arrangement. After several method are compared, it is pointed out that coefficients determined in terms of aperture distribution are effective for compensating gain reduction in widely scanned angle, while they can not control beam isolation. Beam isolation, on the other hand, is effectively improved by designing array coefficients so as to arrange null points of the far field pattern on a circle with its beam direction centered. In this method, number of null points and radius of the circle are determined to get higher beam isolation. Number of null points may be set greater than that of elements, provided null points in the sense of a least mean square are also admissible. A simple parabola with offset angle of 45, fed by 9-horn array thus designed, can scan its beam beyond 10 halfpower beam width, keeping no less than 27 dB isolation between beams with spacing of about 2.0 halfpower beam width apart.

A multiple fiber connector with an alignment hole for a multiple extrusion unit is proposed. An average connector loss of 0.27 dB is achieved by employing index matching oil. Furthermore, the cause of the loss is evaluated, and it is shown that the calculated losses agree with the experimental values.

For use as radiation-resistant fibers, germanium-free optical fiber performs with fluorine-doped cladding were prepared by the PCVD process using various kinds of fluorine raw materials. As a result, numerical apertures as high as 0.3 were attained by using suitable fluorine raw materials.

High efficient coding of monochrome images using new implementation of Rademacher transform is described. A computer simulation has been performed to evaluate performance of the system. The system proposed here shows less sensitivity to type of pictures.

Radiation properties of double-choked circular waveguides fed by TE-11 mode are found experimentally to be sensitive to the choke positions. By properly selecting the load position, better cross-polar properties can be expected.