A boundary element method is presented for the analysis of shielded microstrip lines with dielectric layers. The formulation is based on (a) the Green's second identity, (b) the method of subdomains, (c) the constant boundary element discretization and (d) the discrete conservation law of total charge. In particular, the above (b) and (d) are originated for dealing with the dielectric layers. Numerical results for the balance-type and coplanar-type striplines are shown in order to examine the validity of the boundary element method. By user of the technique of subdivision into boundary element, it is also found that the calculated values for line characteristics are with the second-order accuracy.

This paper considers a repair system which includes several repair stations, many user sites and a great many identical equipments operated in these sites. The means and the variances of the numbers of the equipments in these user sites and repair stations are obtained using an approximation method. The proposed repair model is applicable to a complex repair system such as a multi-echelon repair system.

It has been found experimentally that in double-choked small-aperture circular waveguide antenna, the choke position influences greatly the radiation properties. The cross-polar level is found to be particularly sensitive to the choke positions. When the parameters a, the length between the circular waveguide aperture and the inner choke, and b, the length between the aperture of the inner and the outer chokes, are varied within 0a2.5 mm, 0b7.5 mm, the cross-polar peak values are found to vary by about 10 dB. When, for example, a and b are chosen 0.5 mm and 5.0 mm, respectively, the 45-plane cross-polar value of this double-choked antenna could be reduced to 39 dB. It is also found that the beam circularity of the double-choked feed is improvable by properly choosing the choke-load positions. However, the cross-polar patterns of the test paraboloid with the double-choked feed (a1 mm, b6 mm) produced high cross-polar fields (27 dB). Authors then measured the amount of the reflector reflection, and found that the value of the reflection without a vertex plate was as high as 18 dB. However, by loading a vertex plate 0.65λ from the reflector apex, the cross-polar values of the parabolic reflector was suppressed below 35 dB over the frequency range of 11.4 GHz 12.3 GHz.

This paper presents and analyzes the following queueing model for congestion control. In an M/M (Poisson arrival/exponential service time) type model with finite waiting room, the input rate into the system is gradually controlled by comparing the number of calls in the system with two threshold values. If an arriving call finds the system to be full, the call is lost and the regulation grade is tightened by one level, i.e. the input rate slows down. If a leaving call finds the number of calls in the system to be lower than the lower threshold, input regulation grade is loosened by one level, i.e. the input rate speeds up. The method is called hysteresis" control. An efficient calculation procedure is devised for steady state probabilities. Some numerical results are shown. Here, in the example, mean service time grows linearly with the number of calls in the system. The graphs show that the input regulation method is effective for preventing such a system from falling into a congested state. This analysis can easily be applied to an input regulation model with finite sources.

This paper first defines signal line fault detection testability measure (FDTM) for stuck-at-0 and stuck-at-1 faults. The FDTM is obtained from signal line's 0, 1-controllability and observability measures. This measure is analyzed in terms of the relationships between FDTM and undetected faults under the condition of the D-algorithm ATPG program execution for a certain time. Then, node (element/functional block) testability measure is defined from node's input 0, 1-controllability and observability measures. This measure is also evaluated in terms of the relationships between node testability measure regions and node fault coverage under the condition of the ATPG program execution for a certain time. Finally, the proposed testability measures applications in early design phases and test generation systems are discussed.

Some study was made by the author on stability conditions for the two-dimensional digital filters that are required for image processing. Algorithms for testing the stability of such filters as mentioned above can be obtained by applying Huang's theorem. This theorem, however, has not been proved completely by Huang, and various proofs by use of the maximum principle have been proposed. In this paper is presented a new proof applying the principle of analytic continuation.

This letter improves the technique proposed previously for speeding up stack-controlling LALR(1) parsers. The efficient actions of the improved parsers are more than those of the parsers by the previous scheme.

The electromagnetic scattering coefficient of an infinite elliptic cylinder is presented. We have discussed the fundamental properties of the coefficient in the case of the parallel and perpendicular polarization of the incident plane wave.