In this paper, we will define Kleene-Stone logic functions which are functions F: [0, 1]n[0, 1] including the intuitionistic negation into fuzzy logic functions, and they can easily represent the concepts of necessity and possibility which are important concepts of many-valued logic systems. A set of Kleene-Stone logic functions is one of the models of Kleene-Stone algebra, which is both Kleene algebra and Stone algebra, as same as a set of fuzzy logic functions is one of the models of Kleene algebra. This paper, especially, describes some algebraic properties and representation of Kleene-Stone logic functions.

We propose a new type of Graph Rewriting Systems (GRS) that provide a theoretical foundation for using the reduction method which plays an important role on analyze network reliability. By introducing this GRS, several facts were obtained as follows: (1) We clarified the reduction methods of network reliability analysis in the theoretical framework of GRS. (2) In the framework of GRS, we clarified the significance of the completeness in the reduction methods. (3) A procedure of recognizing complete systems from only given rewriting rules was shown. Specially the procedure (3) is given by introducing a boundary graph (B-Graph). Finally an application of GRS to network reliability analysis is shown.

Let C{c1, , cm} be a family of subsets of a finite set S{1, , n}, a subset S of S is a co-hitting set if S contains no element of C as a subset. By using an O((log n)2) time EREW PRAM algorithm for a maximal independent set problem (MIS), we show that a maximal co-hitting set for S can be computed on an EREW PRAN in time O(αβ(log(nm))2) using O(n2 m) processors, where αmax{|cii1, , n} and βmax{|djj1, , n} with dj{ci|jci}. This implies that if αβO((log(nm))k) then the problem is solvable in NC.

A new method for interpolating boundary function values and first derivatives of a triangle is presented. This method has a relatively simple construction and involves no compatibility constraints. The polynomial precision set of the interpolation function constructed includes all the cubic polynomial and less. The testing results show that the surface produced by the proposed method is better than the ones by weighted combination schemes in both of the fairness and preciseness.

With rapid increase of information requirements from various application areas, there has been much research on the efficient information retrieval. A signature is an abstraction of information, and has been applied in many proposals of information retrieval systems. In this paper we evaluate the performance of various signature-based information retrieval methods and provide guidelines for the most effective usage to a given operational environment. We derive analytic performance evaluation models of these access methods based on retrieval time, storage overhead and insertion time. The relationships between various performance parameters are thoroughly investigated. We also perform simulation experiments by using wide range of parameter values and show that the performance experiments agree with those analytic models.

Theoretical and experimental evaluations of the horizontal rotating and tilting of the base station antenna beam show that these techniques are effective in reducing delay spread. Result show good agreement between predicted and measured values.

This paper reviews the application of optical technologies to phased array antennas. The performance of the fibre transmission medium and of sources and detectors is reviewed, leading to simple expressions for transmission loss and noise performance. Both coherent and non-coherent beam forming techniques are considered. Future trends, including the use of optical amplifiers and coherent signal generation, will also be discussed.

A coplanar-type TW electrode is analyzed for the use within a Ti:LiNbO3 optical modulator. The quasistatic analysis is developed based on the variational principle and the incremental inductance formula. The anisotropy of the LiNbO3, the effect of the SiO2 buffer layer, the overlaid conductor and the electrode thickness can be taken into consideration easily by using the extended spectral domain approach (ESDA) as the formulation procedure. It is shown numerically that the TW electrodes thickness, t, and the overlay spacing, p, are as dominant as the buffer layer thickness d, i.e., the microwave effective index and the product ΔfL is affected significantly by the electrodes thickness t and the overlay spacing, whereas the product VπL is insensitive. Therefore, the introduction of the overlaid conductor and the use of thicker electrodes can be utilized effectively to achieve higher values of the figure of merit Δf/Vπ.

In this paper, optimal static load balancing in a tree hierarchy network that consists of a set of heterogeneous host computers is considered. It is formulated as a nonlinear optimization problem. We study the effects of the link communication time on the optimal link flow rate (i.e., the rate at which a node forwards jobs to other nodes for remote processing), the optimal node load (i.e., the rate at which jobs are processed at a node), and the optimal mean response time, by parametric analysis. We show that the entire network can be divided into several independent sub-tree networks with respect to the link flow rates and node loads. We find that the communication time of a link has the effects only on the link flow rates and the loads on nodes that are in the same sub-tree network. The increase in the communication time of a link causes the decrease in the link flow rates of its descendant nodes, its ancestor nodes and itself, but causes the increase in the link flow rates of other nodes in the same sub-tree network. It also causes the increase in the loads of its descendant nodes and itself, but causes the decrease in the loads of other nodes in the same sub-tree network. In general, it causes the increase in the mean response time.

A typical fault-tolerance technique of systolic arrays is to include redundant processors and links so that the array is reconfigurable when some processors fail. Another typical technique is to implement each processor by a majority voter and N (N3) copies of processors so that the faults of up to N-2 copies of processors can be masked without reconfiguration. This paper proposes a systolic linear array called reconfigurable modular redundant linear array (RMA) that combines these techniques with N4. When up to 2 copies of each processor fail in RMA, the faults can be masked without reconfiguration. When some voters or more than 2 copies of a processor fail, RMA can be reconfigured by specifying a new switch pattern. In order to perform reconfiguration efficiently, we present a reconfiguration algorithm with time complexity O (n), where n is the number of processors in RMA.

Theoretical prediction of propagation is required for the future urban mobile communications, in order to make possible precise and universal prediction for arbitrary conditions. The necessity and the fundamental concept of theoretical prediction are introduced, and the theoretical prediction of mean field strength in urban areas is reviewed and discussed. Theoretical method is important particularly in prediction of multipath delay characteristics, in relation to the prediction of error rates in digital mobile radio communications.

Kleene-Stone algebra is both Kleene algebra and Stone algebra. The set of Kleene-Stone logic functions discussed in this paper is one of the models of Kleene-Stone algebra, and they can easily represent the concepts of necessity and possibility which are important concepts for many-valued logic systems. Main results of this paper are that the followings are clarified: a necessary and sufficient condition for a function to be a Kleene-Stone logic function and a formula representing the number of n-variable Kleene-Stone logic functions.

The inverted slot line (ISL) has been propoaed for millimeter-wave LiNbO3 optical modulator. It is simple in structure, and capable of achieving the perfect velocity matching between carrier and modulating waves. The excellent performance of the ISL optical modulator has been demonstrated at 100 GHz, and the extension into the 50 GHz range is being expected. This paper addresses the analysis of the ISL based on the spectral domain approach. The major results obtained here are the demonstration of the perfect velocity matching not only at 10 GHz but also at 50 GHz, and the characterization of the ISL in terms of effective refractive index, characteristic impedance, overlap integral factor and transmission loss. The depth of optical phase modulation is also estimated at 50 GHz to show a promising performance in the millimeter-wave frequency range. The effective refractive index and the characteristic impedance are found to be theoretically predictable, but the field profile, the overlap integral factor and the transmission loss are not necessarily in good agreement with measurements. As a result of analysis, it can be concluded that the Y-cut substrate is superior to the Z-cut substrate in the following respects: 1. Coupling with the surface wave mode hardly occurs near the operating frequency range. 2. The perfect velocity matching can be attained with a larger spacing between the electrode and the ground plane. 3. The transmission loss is smaller. 4. The field intensity and the voerlap integral factor do not seem to be much deteriorated in the actual ISL.

This paper mainly concentrates on recent studies on land mobile propagation, considering new trends of the progress of digital and personal land mobile communications. High speed digital transmission for millimeter-wave indoor communication is of another current interest. Microcellular propagation in urban areas and indoor propagation are major research targets at present days. Multipath propagation characteristics such as delay-profiles becomes more and more important measuring items, and some signal processing methods like MUSIC method have been widely introduced to improve the time resolution against the limit of available radio bandwidth. Path-loss characteristics in mobile propagation are extended to the path-loss prediction and are going to be applied to cellular system design in connection with the design of directional base-station antennas. Another recent topic is an extension of target frequency bands for mobile propagation studies, which are spreading from VHP, UHF and SHF to EHF bands.

High Tc superconducting (SC) active antennas made from thin films were produced by the magnetron sputtering method. The SC active antennas are found to be good for detecting 50GHz electromagnetic waves. Furthermore, the improvement of the sensitivity of the SC active antennas is demonstrated with the use of a corner reflector.

This paper analyzes the performance of the capacity controlled radio system under a frequency selective fading environment. This system controls the number of modulation levels according to the number of active subscribers. In the analysis, we consider the capacity controlled system either with or without adaptive equalizer. As the results of analysis, it is clarified that the system is superior to the conventional fixed capacity system, and can be considered as a good countermeasure for multi-path fading. And it is found that there exists a synergistic effect due to capacity controlling and adaptive equalizing.

This paper reports the influence of optical reflection induced noise and distortion for optical fiber feeder systems for microcellular mobile communication systems. Since the optical feeder requires very wide dynamic range, noise and distortion must be suppressed to an extremely low level. From optical transmission experiments and theoretical analysis, the basic characteristics of the reflection induced noise and distortion were investigated. By using these results, it was estimated that, for currently used analog mobile telephone systems, the number of connectors with 35 dB reflectance must be limited to less than 17, in order to suppress the noise caused by the connector reflections. Moreover, it was confirmed that the reflection induced distortion drastically decreases according to the increase of the length between reflectors. Therefore, the distortion can be suppressed by expanding the connector spacing to more than 7 meters.

We apply Fahlman and Lebiere's (FL) algorithm to network synthesis and incremental learning by making use of already-trained networks, each performing a specified task, to design a system that performs a global or extended task without destroying the information gained by the previously trained nets. Investigation shows that the synthesized or expanded FL networks have generalization ability superior to Back propagation (BP) networks in which the number of newly added hidden units must be pre-specified.

The various propagation characteristics of millimeter waves in silicon rib and image guides containing the optically induced plasma region have been investigated. Phase shift and attenuation properties resulting from the presence of plasma are evaluated using the effective dielectric constant method. Experiments have been carried out to demonstrate the optical control of millimeter waves at frequencies ranging from 3350 GHz using high-resistivity silicon illuminated by a high-power Xenon arc lamp and light emitting diodes. Optical control of millimeter wave attenuation of 20dB has been confirmed for a guide of length 90 mm and plasma density of 1021/m3 with average plasma thickness of 20 µm. To increase the sensitivity of optical control, Bragg reflection filter characteristics are studied and its stop band characteristics have been calculated using the transmission line model, and confirmed experimentally. To further develop the Bragg reflection filter, a Mach-Zehnder interferometer guide with one of the arms periodically corrugated is newly proposed and its optical control performance is confirmed by experiments. Finally the field distributions of the Mach-Zehnder configuration of rib waveguides are measured by a simple optical probing technique using the focused laser spot.

This paper reviews Ti:LiNbO3 and semiconductor optical waveguide modulators. The operating principle of the Ti:LiNbO3 optical waveguide modulator is based on the Pockels effect. On the other hand, semiconductor optical modulators can be operated based on the Pockels effect, the Franz-Keldysh effect, or the quantum confined stark effect (QCSE) by employing multiple quantum wells (MQWs). Ti:LiNbO3 optical waveguide modulators are discussed with emphasis on the velocity-matching and optical waveguides. MQW optical waveguide modulators are discussed in view-point of design of a MQW structure, waveguide and modulation bandwidth.