Uniform bending losses of single-mode fibers are experimentally studied. The effects of a dip in the refractive index at the center of the core, bending radius and fiber parameters on the bending losses were investigated. An experimental equation for the bending loss of a single-mode fiber with a small dip have been obtained as an exponential function of the bending redius and the fiber parameters. It essentially agrees with the theoretical equation.

A service specification description method for communication control machines (CCM), called the multilogue-set method", is proposed. This method is well suited for the discussion of the CCM renewal in response to service addition requests.

There are two purposes in this paper. The one is to compare experimentally the two types of methods of writer identification, structure analysis and pattern matching, and the other is to examine the dependency of identifiability on letters. The material was provided by seven persons who handwrote a sentence of twenty-six letters twenty-five times repeatedly. About a half of the material was used as a sample for learning and the rest was for test. Templates representing persons were constructed from the sample for learning through each of five methods, three of structure analysis S1, S2, S3 and the other two of pattern matching P1, P2. For each character in the sample for test, the distances from it to the templates were evaluated and the person who was the nearest was judged as the writer. Experimentally the average correct identification rate for P1, which is better than P2, was about 85%, while that for S2, which is better than S1 and S3, was about 80%. As far as the methods of structure analysis proposed by us are concerned, they are inferior to the methods of pattern matching. As for sentences, all of the writers were correctly identified. The correct identification rates for HIRAGANA letters are in general greater than those for KATAKANA, which seems to imply that complicated letters transmit us more information about writers than simple letters do.

A systematic method for synthesizing multi-port networks specified by scattering matrices is proposed. First, a basic circuit for converting the port parameters is introduced. At each port the basic circuit converts the voltage and the current into the incident and the reflected wave quantities. Then each element of the scattering matrix is realized using the conventional techniques for the realization of one-input one-output transfer functions. When all the elements of the scattering matrix are either positive constant or zero, the resultant network can be simplified. With the proposed method, some known structures can be obtained very easily and two new structures for hybrid networks are derived. One of the salient feature of the proposed method is that it also provides the physical interpretation of structures derived. Experimental results are also given.

In Adaptive Ground-Implemented Phased Array (AGIPA) system, signals received with each element of the array on-board a satellite are transferred to the Earth station for further adaptive processing to form a radiation pattern. For transmission from the satellite to the Earth station, a certain signal multiplex method will be applied. Among the multiplex methods, the simplest one is a frequency-division-multiplex (FDM) technique. This paper deals with the effect of satellite-borne transmitter non-linearity when FDM technique is applied to the AGIPA system. Analysis, assuming a two-element array, shows that for the FDM-AGIPA sysmte, the nonlinearity causes spurious interferences which seriously affect the performance of AGIPA system for interference rejection.

An electronic model, which can simulate a scotopic electroretinogram (ERG), has been manufactured for trial. And we have obtained the effective clues to clarify technologically the mechanism of the generation of the scotopic ERG components.

Realizability criteria for infinite dimensional time-varying linear dynamical systems are studied. We set up the problem of realization and obtain some necessary and sufficient conditions for given matrix weighting patterns to be realized by the above mentioned systems in which state spaces are Banach spaces or Hilbert spaces. Moreover, we show that the problem of realization in infinite dimensional systems is not trivial, that is, there are realizable weighting patterns which are not realized by finite dimensional time-varying systems. The theory of evalution operators in Banach spaces plays an important role in our study.

All of the characteristics of the batwing rediator, which is the heart of the superturnstile antenna system, are theoretically calculated by using the Moment Method. The original type, based on this antenna, and the modified batwing antennas, types I, II and III in total of four were examined. The modified batwing antenna type I is used as a horizontally polarized wave antenna among the circularly polarized wave antennas developed by RCA in the U.S.A. as a countermeasure for the ghost phenomena, while type II is used as an antenna having wide band characteristics for IFF receiving. Type III is a combination of types I and II. The characteristics of the above stated four types of antennas are analyzed theoretically by the use of the Moment Method and the results are compared through the use of measurement. Furthermore, the matching condition is obtained on the basis of the characteristics in the cases of changing the shape of the jumper and of changing the distance between the support mast and the antenna elements.

The amount of memory space required by a branch-and-bound algorithm depends on the search strategy used in the algorithm. From the viewpoint of implementing branch-and-bound algorithms, it is desirable that the amount of memory space can be bounded to some feasible size. In this paper, we propose two new search strategies for branch-and-bound algorithms, by which the amount of required memory space is controllable. These strategies are named pdfs (parallel depth-first search)" and blis (breadth limited search)", respectively. One of the main results of this paper is that (a) the amount of required memory space of any of these strategies is a linear function of the size of the given problem and (b) the amount of required memory space is controllable by adjusting appropriate parameter. That is, these search strategies are adaptable to the available memory space. Another result of this paper is that the computational performance of a branch-and-bound algorithm, using any of these strategies, can be improved by adjusting appropriate parameters.

A mathematically rigorous treatment of the electromagnetic scattering problem of dielectric cylinders based upon the finite element method is presented. The problem is formulated in the variational terms in two different forms depending upon the matching condition at the artificial boundary.

This paper reports on the overflow process for a trunk reservation system which has two kinds of Poisson inputs. The Laplace-Stieltjes transforms of the interoverflow distributions for each of priority calls and ordinary calls are derived, respectively. The overflow process for priority calls is renewal. The Laplace-Stieltjes transform of the interoverflow distribution for priority calls is represented by the recurrences, and the variance of overflow traffic can be easily obtained by the theory of GI/M/ model. The overflow process for ordinary calls is semi-Markovian, since it depends on the number of busy trunks. The Laplace-Stieltjes transform for the semi-Markovian kernel, depending on the number of busy trunks, is derived. The variance can be obtained by the theory of semi-Markovian inputs model, SM/M/. The total overflow process for both priority and ordinary calls is also derived, but in this case the semi-Markovian kernel is more complicated than that for the overflow process for ordinary calls. The variance of the total overflow traffic being analyzed, the covariance for the two kinds of overflow traffic can be easily obtained. Moreover, some numerical results are shown and characteristics of the overflow traffic are discussed.

This paper considers a multi-base single repair station problem which is a reliability analysis for a system with a large number of equipments operated in their own bases and some repairmen in the repair station. In this problem, all the failed equipments are repaired in the repair station and are sent back to their own bases after completions of repair. The mean and the variance of the number of operative equipments in each base are obtained by a diffusion approximation method. Numerical examples of an approximation solution and a simulation solution are presented.

This paper presents an approach to the realization of low-sensitivity second-order digital filters. In contrast to existing methods, which use amplitude sensitivity as a criterion, the proposed method uses pole sensitivity. Pole sensitivity is quite useful for evaluating and comparing the performance of various types of filters because it is not a function of frequency. The relation between pole sensitivity and amplitude sensitivity is clarified, and it is shown that the minimization of amplitude sensitivity is equivalent to that of absolute value of pole sensitivity. For the minimization of pole sensitivity, the denominator polynomial of a second-order transfer function is expressed in a general form including two multiplier coefficients and some arbitrary integer parameters. Under certain constraints on the range of the parameters, which limit the filter complexity, the values of the parameters are determined through an exclusive search such that the pole sensitivity is minimized. The optimum set of the parameters are fully dependent on the given specifications, i.e. locations of the poles. Therefore the z-plane can be partitioned into some regions, in each of which a single set of the parameters is chosen. The resultant map enables one to realize low-sensitivity digital filters having any given characteristics. Finally, two illustrative examples are included.

If there is high uncertainty in the reliability of a system, it is required to know for which components to collect further failure data for making the uncertainty lower. This paper provides some solutions for such a requirement. First, the variance importance of a component is defined as a measure of component's contribution to the variance of the distribution of system unreliability. For reducing the system-variance efficiently, it would be suitable to collect failure data of comopnents having greater values of variance importance. Next, in the situation that we will perform life tests of components for making the variance of the distribution of system failure-rate smaller than its prior value, some problems for determinig both the number of samples to be tested and the test time for each component are formulated and solved.

This paper deals with two optimal preventive maintenance policies, i.e., Policy I and Policy II proposed by R. Barlow and L. Hunter, and in particular emphasizes on the characteristics of the optimal maintenance theories due to numerical analysis. Through this paper, the Weibull model is adopted as a failure modes and its shape parameter β plays an important role. According to the results newly obtained, we discuss the characteristics of the two types of policies and their advantages and disadvantages. Next, the new results are applied to the field data of failure and maintenance in order to investigate the actural maintenance techniques.

In this short note, an upper limit of modulation enhancement of electronic phase shifter employing a multilayer dielectric-waveguide structure is provided by the application of general theory of dielectric waveguides.

The composite dielectric waveguides with multi-boundaries in radial directions have axially unsymmetrical structures. To have the large difference in propagation constant for the two orthogonal HE11 modes, the waveguides have attracted our attention as a new type of single-polarization optical fibers. In this paper, the modal characteristics of the composite dielectric waveguides are investigated by a numerical analysis based on the point-matching method. The dispersion characteristics for millimetric dielectric waveguides with large difference in dielectric constant as well as single polarization optical fibers with small difference in refractive index are shown. Also, the patterns of electric field distributions for propagating modes are illustrated. The propagation constants are obtained with three significant figures for both the dominant and higher order modes. Microwave model experiments using a composite dielectric waveguide made of Rexolite and Teflon were carried out to confirm the theory.

Refractive-index dispersion mesuarements were performed using the minimum deviation method for bulk specimens at wavelengths from 0.4047 to 2.0581µm. The data were utilized to calculate an optimum index profile,αop, and zero-material-dispersion wavelength,λ0, for the optical fiber. For GeO2-SiO2 glass core fibers,αop values are 1.93 at 1.30µm, and 1.88 at 1.55µm. There are independent of GeO2 concentration. The wavelength λ0 shifts from 1.272 to 1.376µm, proportionally to the GeO2 concentration from 0-19.3 mol%. The data also show that the addition of P2O5 slightly increases material dispersion, and the value of αop for the P2O5-SiO2 core glass decreases monotonically from 2.16 at 0.4 µm to 1.91 at 2.0µm.

This paper describes charging and deflection characteristics of a binary multi-nozzle ink jet printer. In a binary printer, ink drops are selectively deflected by applying a charge to them, while uncharged drops proceed in a straight line to form the part of characters. The printer used in our experiment has eight nozzles, 55µm in diameter and on 0.5 mm centers. Charging electrode slot width is 0.3 mm. Drop frequency is 40 kHz. Drop frequency is divided into printing frequency by 16 so that a moderate printing speed is obtained. The charge electrode array is positioned with respect to a nozzle array so that the drop formation occurs within a certain region inside the charge electrode slots. Then no crosstalk between the adjoining electrodes has been observed and the induced charge by the previously charged drop can be neglected. The deflection condithion, for defect-free prints, is such that the charged drops are collected into a catcher whereas the charged drops do not merge with the uncharged drops. The charging voltage and the separation between the undeflected ink streams and the deflection plated are important parameters. Experimentally a sufficient amount of deflection has been obtained by the image force of the charged drops without the use of a high deflection voltage.

A fast identifying method of animation line drawings composed of some ten closed regions is described by the use of spatial location and adjacent relation among closed regions contained in successive two frames of the line drawings. The method consists of global and local matching. The global matching identifies closed regions which change slightly in size and shape as a set of three closed regions in each of successive two frames by the use of a relaxation method. In the local matching, closed regions identified in the global matching are taken as seeds around which new interpritations may grow, and unidentified closed regions which are adjacent to the seeds and have similar location relation are identified by taking vectors drawn between centroids of closed regions as parameters. The mechod is applied to a series of sixteen line drawings, and all the closed regions contained in the line drawings are correctly identified excepting closed regions newly appeared in successive two frames.