This paper presents an improved method of speaker verification using the sequential probability ratio test (SPRT), which can treat the correlation between successive feature vectors. The hidden Markov model with the mean field approximation enables us to consider the correlation in the SPRT, i. e. , using the mean field of previous state, probability computation can be carried out as if input samples were independent each other.

To realize S-band mobile satellite communications and broadcasting systems, the onboard mission system and equipment were designed for the Japanese Engineering Test Satellite VIII. The system performs voice communications using handheld terminals, high-speed data communications, and multimedia broadcasting through a geostationary satellite. To enhance system efficiency and flexibility, the onboard mission system features phased-array-fed reflector antennas with large antenna diameter and baseband switching through onboard processors. Configurations and performance of the subsystems and key onboard equipment, large deployable reflectors, feed arrays, beam forming networks and onboard processors, are presented. The S-band mobile systems and onboard equipment will be verified through in-orbit experiments scheduled for 2002.

The relationships between lattice orientation of the electron-beam evaporated MgO layer used as protecting layer for ac plasma displays (ac-PDPs) and the discharge characteristics of color ac-PDPs were investigated by the measurements of ion-induced secondary electron emission. It is proved that values of γi for MgO are large in the order of (220) orientation, (200) orientation, and (111) orientation, that is, γi(220) > γi(200) > γi(111). The values of φ for different lattice orientation are obtained by the measurements of thermionic emission and photo emission. The aging measurements for testing panels with the different lattice orientation of MgO layer revealed that performance of those panels are excellent in the order of (220), (200), and (111). In particular, luminance and luminous efficiency become larger in the order of (220), (200), and (111). It is pointed out that the degree of longevity, sustaining voltage, and memory margin for ac-PDPs with protecting materials as MgO are estimated by the measurements of γi.

For the realization of low-voltage full-color FEDs, requirements for phosphor for the FED are proposed. Especially, the influence of released gases or substances from phosphors on the field emission within the FED was made clear. It was clarified that the analysis of F-N plots of the V-I curve of field emission characteristics was helpful to know the interaction of field emission and phosphors. In the experiment, we first obtained the depth from the phosphor surface of the low voltage electron excitation in case of ZnGa2O4, where the region available for cathodoluminescence at the anode voltage of 400 V is about 63 nm deep from the surface. The characteristic of the 12.4 cm-320(trio)240 pixels low-voltage full-color FED is reported. The luminance of 154 cd/m2 was attained at the anode voltage of 400 V and the duty factor of 1/241. Supported by the high potential of the FED as a flat panel, each problem shall be steadily solved to secure the firm stand as a new full color flat display in new applications.

Negation as failure is realized to be combined with SLD resolution for general logic programs, where the combined resolution is called an SLDNF resolution. In this paper, we introduce narrowing and infinite failure to SLDNF resolution for general logic programs with equations. The combination of SLDNF resolution with narrowing and infinite failure is called an SLDNFN resolution. In Shepherdson (1992), equation theory is combined with SLDNF resolution so that the soundness may be guaranteed with respect to Clark's completion. Generalizing the method of Yamamoto (1987) for definite clause sets with equations, we formally define a least fixpoint semantics, which is an extension of Fitting (1985) and Kunen (1987) semantics, and which includes the pair of success and failure sets defined by the SLDNFN resolution. The relationship between the fixpoint semantics and the pair of sets is regarded as an extension of the relationships for general logic programs as in Marriott and et al. (1992) and in Yamasaki (1996). Instead of generalizing Clark's completion for SLDNFN resolution, we establish, as a model for general logic programs with equations, an extended well-founded model so that the SLDNFN resolution is sound and complete for non-floundering queries with respect to the extended well-founded model.

In this paper we study the evolution of the resonance zones that appear in connection with a Hopf-pitchfork bifurcation exhibited by a Z2-symmetric electronic circuit. These regions, bounded by curves of folds (saddle-node bifurcations) may be closed or open depending on the values of the parameters. An angular degeneracy on the torus bifurcation curve originates the banana shape of Arnold's tongues. The presence of homoclinic bifurcations is also pointed out.

Though considerable effort has recently been devoted to hardware realization of one-dimensional chaotic systems, the influence of implementation inaccuracies is often underestimated and limited to non-idealities in the non-linear map. Here we investigate the consequences of sample-and-hold errors. Two degrees of freedom in the design space are considered: the choice of the map and the sample-and-hold architecture. Current-mode systems based on Bernoulli Shift, on Tent Map and on Tailed Tent Map are taken into account and coupled with an order-one model of sample-and-hold to ascertain error causes and suggest implementation improvements.

Shared multibuffer ATM switches are attractive since they can extend memory bandwidth by the use of multiple independent buffer memories. Although the parallel accessibility allows a considerable improvement in memory bandwidth, a proper assignment of memory addresses to cells is necessary to better utilize the potential bandwidth. In this paper, we present an efficient cell placement strategy for shared multibuffer ATM switches. It is based on a combination of two key concepts, uniform distribution for writes and reference locality for reads. The former is to reduce cell loss ratio due to overflow and write-access conflicts. The latter is to have cells destined for the same output port read from the same buffer memory to minimize read-access conflicts. A single threshold is employed to assign memory locations adaptively depending on the cell distribution among the shared buffer memories. The proposed strategy is shown to outperform the existing ones, in terms of cell loss ratio, cell delay, and throughput. Moreover, the performance gains have been made with a simple control circuit.

We developd a method of implementing a multiple-valued Hopfield network on electronic circuits by using single-electron circuit technology. The single-electron circuit shows quantized behavior in its operation because of the discrete tunnel transport of electrons. It can therefore be successfully used for implementing neuron operation of the multiple-valued Hopfield network. The authors developed a single-electron neuron circuit that can produce the staircase transfer function required for the multiple-valued neuron. A method for constructing a multiple-valued Hopfield network by combining the neuron circuits was also developed. A sample network was designed that solves an example of the quadratic integer-programming problem. And a computer simulation demonstrated that the sample network can converge to its optimal state that represents the correct solution to the problem.

We successfully fabricated plastic ferrules and split alignment sleeves for single-mode fiber-optic connectors by the injection molding process. Liquid crystalline polymer (LCP) was used as the molding material for the ferrule. We introduced an eccentricity control mechanism into the ferrule mold and realized an eccentricity of less than 1 µm. As the molding material for the sleeve, thermosetting epoxy resin was used. Suitable mechanical properties were realized by employing appropriate dimensional design and the molding process. The optical characteristics of a system combining these plastic components are compatible with single-mode SC-type connectors and are also stable under hot and humid conditions.

Precise plastic V-grooved alignment parts for connecting single-mode optical fiber arrays to multi-port optical devices were successfully molded with a thermosetting resin by using a highly productive injection molding technique. The molded parts are two types of V-grooved blocks that are compatible with the size of optical devices having eight or twelve optical ports. Their dimensional accuracy must be better than 1 µm over the whole length of the V-grooves for efficient optical coupling. This strict requirement was satisfied using precisely processed molding tools with a specially chosen resin under optimum molding conditions. The feasibility of the optical alignment parts was assured by an evaluation of their loss characteristics and reliability in coupling single-mode fibers to 18 power splitters, where the average optical loss was 0.2 dB and the change in loss was less than 0.2 dB under a temperature cycling test and also under a damp heat test. These results show that plastic molded parts can be used for precise coupling of single-mode optical devices, and will lead to a breakthrough in innovation in the field of optical packaging.

Precise plastic V-grooved alignment parts for connecting single-mode optical fiber arrays to multi-port optical devices were successfully molded with a thermosetting resin by using a highly productive injection molding technique. The molded parts are two types of V-grooved blocks that are compatible with the size of optical devices having eight or twelve optical ports. Their dimensional accuracy must be better than 1 µm over the whole length of the V-grooves for efficient optical coupling. This strict requirement was satisfied using precisely processed molding tools with a specially chosen resin under optimum molding conditions. The feasibility of the optical alignment parts was assured by an evaluation of their loss characteristics and reliability in coupling single-mode fibers to 18 power splitters, where the average optical loss was 0.2 dB and the change in loss was less than 0.2 dB under a temperature cycling test and also under a damp heat test. These results show that plastic molded parts can be used for precise coupling of single-mode optical devices, and will lead to a breakthrough in innovation in the field of optical packaging.

In this paper, a general formula of disparity estimation based on Bayesian Maximum A Posteriori (MAP) algorithm is derived and implemented with simplified probabilistic models. The formula is the generalized probabilistic diffusion equation based on Bayesian model, and can be implemented into some different forms corresponding to the probabilistic models in the disparity neighborhood system or configuration. The probabilistic models are independence and similarity among the neighboring disparities in the configuration. The independence probabilistic model guarantees the discontinuity at the object boundary region, and the similarity model does the continuity or the high correlation of the disparity distribution. According to the experimental results, the proposed algorithm had good estimation performance. This result showes that the derived formula generalizes the probabilistic diffusion based on Bayesian MAP algorithm for disparity estimation. Also, the proposed probabilistic models are reasonable and approximate the pure joint probability distribution very well with decreasing the computations to O(n()) from O(n()4) of the generalized formula.

This paper develops a deterministic model for evaluating the influence of building windows upon the outdoor-to-indoor propagation path in cellular systems. This prediction model is based on the Aperture-field method of Huygens-Fresnel wave theory. Penetration losses and indoor signal characteristics are analyzed. It is found that the window frames of the building play an important role in determining the indoor field intensities. In order to verify this model's accuracy, numerical results are compared with measurement values. The calculations agree well with the measurements.

A new IC interconnect transmission line parameter determination methodology and a novel fast simulation technique for non-uniform transmission lines are presented and verified. The capacitance parameter is a strong function of a shielding effect between the layers, while silicon substrate has a substantial effect on inductance parameter. Thus, they are taken into account to determine the parameters. Then the virtual straight-line-based per unit length parameters are determined in order to perform the fast transient simulation of the non-uniform transmission lines. It was shown that not only the inductance effect due to a silicon substrate but also the shielding effect between the layers are too significant to be neglected. Further, a model order reduction technique is integrated into Berkeley SPICE in order to demonstrate that the virtual straight-line-based per-unit-length parameters can be efficiently employed for the fast transient response simulation of the complicated multi-layer interconnect structures. Since the methodology is very efficient as well as accurate, it can be usefully employed for IC CAD tools of high-performance VLSI circuit design.

A complex modular process flow was developed for PRISM technology to permit increased system integration. In order to combine the required functions--submicron CMOS Logic, Nonvolatile Memories, Precision Linear, and Power Drivers--on a monolithic silicon chip, a highly structured, systematic approach to process synthesis was developed. TCAD tools were used extensively for process design and verification. The 60 V LDMOS power transistor and the Flash memory cell built in the technology will be described to illustrate the process synthesis methodology.

We propose a new inverse modeling method to extract 2D channel dopant profile in an MOSFET. The profile is extracted from threshold voltage (Vth) of MOSFETs with a series of gate lengths. The uniqueness of the extracted channel and drain profile is confirmed through test simulations. The extracted profile of actual 0.1 µm nMOSFETs explains reverse short channel effects (RSCE) of threshold voltage dependent on gate length including substrate bias dependence.

A neuron-MOS transistor (νMOS) is applied to current-mode multi-valued logic (MVL) circuits. First, a novel low-voltage and low-power νMOS current mirror is presented. Then, a threshold detector and a quaternary T-gate using the proposed νMOS current mirrors are proposed. The minimum output voltage of the νMOS current mirror is decreased by VT (threshold voltage), compared with the conventional double cascode current mirror. The νMOS threshold detector is built on a νMOS current comparator originally composed of νMOS current mirrors. It has a high output swing and sharp transfer characteristics. The gradient of the proposed comparator output in the transfer region can be increased 6.3-fold compared with that in the conventional comparator. Along with improved operation of the novel current comparator, the discriminative ability of the proposed νMOS threshold detector is also increased. The performances of the proposed circuits are validated by HSPICE with Motorola 1.5 µm CMOS device parameters. Furthermore, the operation of a νMOS current mirror is also confirmed through experiments on test chips fabricated by VDEC*. The active area of the proposed νMOS current mirror is 63 µm 51 µm.

The magnetic shielding performance of the high-Tc superconducting (HTS) plate in a mixed state has been investigated numerically. By taking account of the crystallographic anisotropy of the HTS plate, the axisymmetric shielding plate is assumed to have a multiple thin-layer structure. Under the assumptions, the governing equations of the shielding current density can be expressed in terms of a scalar function. The numerical code to integrate the equation has been developed and, by use of the code, the shielding current density and the damping coefficient are calculated for the axisymmetric HTS plate in a mixed state. The results of computations show that the shielding current density localizes around the edge under the high-frequency magnetic field. With an increasing frequency of the applied magnetic field, the localization becomes remarkable and the shielding current density becomes larger until the flux flow occurs. In addition, the magnetic shielding performance of the HTS plate drastically changes with time under the low-frequency magnetic field below 100 Hz, whereas it is almost time-independent under the high-frequency magnetic field. Moreover, it turns out that the HTS plate can shield ac magnetic fields with a high frequency even if it remains in a mixed state.

We propose an H-plane manifold-type triplexer with closely arranged junctions. Broadband characteristics for each bands are obtained by arranging filters closely near the end of the common waveguide. Three fundamental and sufficient parameters are introduced for numerical optimizations to determine the configuration of the broadband triplexer. The configuration including closely arranged junctions requires an generalized scattering matrix (GS matrix) of an asymmetric cross junction to simulate and design. We expand the mode matching technique (MMT) to be able to analyze this kind of discontinuities by joining two asymmetric steps discontinuities to a symmetric cross junction. This is suitable expressions for numerical calculations. The characteristics of the whole triplexer are obtained by cascading GS matrices of the corresponding discontinuities. The experimental results of the fabricated triplexer were compared with the simulated data, and the results agree well with the simulated one. The characteristics of the fabricated triplexer satisfy the request of the broad band operation and high power-handling capability.