This paper considers an availability analysis and an optimal inventory problem for a repairable 1-out-ofN:G system assuming an ordering policy of (s, s+1) type. The system consists of N identical subsystems which constitute 1-out-ofN:G, and each subsystem is a m units series system. Since the system is repairable, the exact evaluation of the system availability is extremely difficult. In this paper, the system availability is obtained by an approximation analysis. The results are reasonably accurate and are much easier than the exact evaluation. Then the optimal inventory problem is discussed. The numerical example shows that the solution is obtained relatively easily when the system consists of highly reliable units.

From circle to circle correspondence in mapping theory of the linear function Z(ah+b)/(ch+d), it is known that Z also describes a circle when its variable h describes a circle or a straight line. From this point of view, the linear functional expression of bio-electrical impedance having a circular locus was discussed in detail. As a result, it became clear that three types h₀, h₁ and h₂ exist of the variable h and the characteristics of bio-impedance expressions for each of h₀, h₁ and h₂ are follows. For the expression by h₀: (1) A polarization impedance having a constant phase angle appears. (2) The most original equation of bio-impedance can be proposed. (3) The linear or nonlinear bio-impedance can be deduced from this original equation. (4) The equivalent circuits satisfying Cole-Cole's circular arc are of two types. For the expression by h₁ and h₂: (1) These expression correspond to the expression using the combination in group theory of the linear function. (2) The circuit elements of equivalent circuits can not be uniquely determined. (3) Taking account of combination, countless equivalent circuits satisfying Cole-Cole's circular arc exist.

The present paper has the following three major objectives:
a) To propose a new hierarchical clustering algorithm based on a powerful distance measure defined by using k-nearest neighbor.
b) To discuss the validity problem of clustering.
c) To describe the need of the constructed data sets for validation of clustering algorithms and to execute the validation of several algorithms including ours using the data sets.
Section 2 describes the authors' view of cluster analysis and cluster itself where discussion is made lying stress on the necessity of establishing the concept of a cluster and developing an efficient clustering algorithm free from any restriction associated with the most existing ones. In Sect. 3, a new hierarchical clustering algorithm is proposed which can be considered as a modified version of single-link algorithm. The algorithm is based on a powerful distance measure defined by using the idea of k-nearest neighbor. In Sect. 4, some four-dimensional data for testing the validity of clustering algorithms is presented along with how to construct them. Section 5 describes some results of computer simulation of several clustering algorithms including ours using the constructed data. The results show the efficiency of out algorithm.

Ceramic plates and glaze glass are studied as the materials employed in developing a highly reliable glazed ceramic substrate. The glazed ceramic substrate is fabricated by applying a thin coating of glass to a 2 mm thick ceramic plate. The substrate is designed for use in a hybrid IC repeater in the CS-36M submarine cable system. The glazed ceramic substrate must have sufficient mechanical strength to withstand the stress under load occurring during the repeater installation, the surface smoothness and heat resistance required during forming of the repeater circuit, and the high electrical resistance to assure long-term, stable operation of the repeater circuit. A comparative study was made of alumina and beryllia for surface form, mechanical strength, heat resistance, and electrical resistance under required conditions for repeater parts in the CS-36M submarine cable system. As a result, an alumina plate with an Al₂O₃ content greater than 97% was selected as the ceramic plate in view, especially, of its surface form and mechanical strength. The glass used for glaze must have excellent glass formability, heat resistance which allows no change in form up to 600, and long-term, stable electrical resistance. From this point of view, excellent compositions were developed on the basis of SiO₂-Al₂O₃-CaO and SiO₂-Al₂O₃-BaO systems. A large glazed ceramic substrate, 110 mm in diameter, was fabricated using the ceramic plate and glass selected here and it was applied in a repeater in the CS-36M submarine cable system.

A boundary element solution is formulated for steady-state convective diffusion equation with the Dirichlet's boundary condition. A simple example is considered in three dimensions. It is shown that the boundary element solution is unconditionally stable. In order to demonstrate the usefulness of the boundary element solution, the comparison with finite element solutions is given.

A Multi-font KANJI Generator has been developed, which can generate dotted Japanese characters KANJI" of several fonts and variable size using less memory than usual KANJI generators. In the compression of JANJI, original KANJI dotted patterns are decomposed into strokes (line segments) according to special rules, which are called ruled strokes, and the coordinates of the start and the end points of the ruled stroke are stored into ROM. Moreover higher data compression is achieved by a special data structure, which allows efficient use of many geometrically similar patterns shared by several KANJI patterns. A variety of KANJI fonts can be generated by changing the rule for the interpolation between the start and the end point of the characterized strokes. The characteristics of this device are; (1) requisite memory capacity is only about 1/4 that of the usual KANJI ROM which is not compressed, (2) three founts and various inclined KANJI patterns can be generated other than the standard MINCHO font, (3) variable character sizes can be generated other than the standard character size, i.e. 2424 dots.

A set of integral equations is derived for a coupling problem in which a wire is energized by an electromagnetic wave through an aperture of a narrow slot. In order to facilitate the numerical treatment, the kernels of the integral equations are simplified so that neither derivatives nor integrals are contained. Typical examples, including a finite and an infinite wire are analyzed using the present integral equations. The currents on the wires and the axial distributions of the slot magnetic currents are demonstrated. It is found that the current induced on the infinite wire is characterized by a traveling wave which does not decay and a wave which dies out rapidly as it travels along the wire.

This paper presents a hybrid-mode analysis for computing the resonant frequencies of a shielded coupled microstrip resonator. This analysis is based upon Galerkin's method in the Fourier transform domain. The computed resonant frequencies of even and odd modes agree will with the measured values for alumina substrates. Furthermore, a variety of numerical data for resonant frequencies are shown.

The main purpose of this paper is to show that, for any L(n) such that L(n)logn and [L(n)/n]0, L(n) space bounded alternating on-line Turing machines with only universal states are less powerful than ordinary L(n) space bounded alternating on-line Turing machines. Closure properties are also discussed.

Threshold-voltage instability of MOS transistors in an LSI memory under accelerated operating test conditions at 77K has been studied. It is found that the dominant cause of threshold-voltage instability at 77K is the generation of positive charge which may be associated with the dissociation of Si-H bonds by interaction with hot electrons injected into the gate-oxide.

In the field of computer animation, effective methods are required, because of a large number of complicated line drawings. In this paper, an inbetweening method of animation characters is described for a mini-computer system.

Periodic variations of sum-frequency output are observed in upconversion of 10.6 µm radiation from a CO₂ laser in a proustite crystal pumped by a Nd:YAG laser beam and concluded to be caused by multiple reflection of infrared wave which occurs inside the nonlinear crystal.

We define three parameters for feature extraction of body surface isopotential maps. It was found that these parameters marked different characteristics according to the different patterns of the maps.