This paper investigates a multihopping scheme for MFSK (Multilevel Frequency Shift Keying) /FH-SSMA (Frequency Hopping-Spread Spectrum Multiple Access) system. Moreover, we propose and investigate a modified decoding scheme for the coded MFSK/FH-SSMA system. In this multi-hopped MFSK/FH-SSMA system, several hopping frequencies per chip are assigned and transmitted in parallel in order to improve its frequency diversity capability for a fading channel. We theoretically analyze the performance of the multihopped MFSK/FH-SSMA system in a Rayleigh fading channel. Moreover, in the coded MFSK/FH-SSMA system, we propose a modified scheme of the error and erasure decoding of an error-correcting code. The modified decoding scheme utilizes the information of rows having the largest number of entries in the decoded time-frequency matrix. Their BER (Bit Error Rate) performance is evaluated by theoretical analysis in order to show the improvement in user capacity.

This paper introduces the concept of an extended pseudo-biorthogonal basis" (EPBOB), which is a generalization of the concepts of an orthonormal (OB), a biorthonormal (BOB), a pseudo-orthogonal (POB), and a pseudo-biorthogonal (PBOB) bases. Let HN be a subspace of a Hilbert space H. The concept of EPBOB says that we can always construct a set of 2M (MN) elements of H but not necessarily all in HN such that like BOB any element f in HN can be expressed by fMΣm=1(f,φ*m)φm. For a better understanding and a wide application of EPBOB, this paper provides their characterization and shows how they preserve the formalism of BOB. It also shows how to construct them.

An attempt to apply neural networks to the acoustic diagnosis for the reciprocating compressor is described. The proposed neural network, Hybrid Neural Network (HNN), is composed of two multi-layered neural networks, an Acoustic Feature Extraction Network (AFEN) and a Fault Discrimination Network (FDN). The AFEN has multi-layers and the number of units in the middle hidden layer is smaller than the others. The input patterns of the AFEN are the logarithmic power spectra. In the AFEN, the error back propagation method is applied as the learning algorithm and the target patterns for the output layer are the same as the input patterns. After the learning, the hidden layer acquires the compressed input information. The architecture of the AFEN appropriate for the acoustic diagnosis is examined. This includes the determination of the form of the activation function in the output layer, the number of hidden layers and the numbers of units in the hidden layers. The FDN is composed of three layers and the learning algorithm is the same as the AFEN. The appropriate number of units in the hidden layer of the FDN is examined. The input patterns of the FDN are fed from the output of the hidden layer in the learned AFEN. The task of the HNN is to discriminate the types of faults in the compressor's two elements, the valve plate and the valve spring. The performance of the FDN are compared between the different inputs; the output of the hidden layer in the AFEN, the conventional cepstral coefficients and the filterbank's outputs. Furthermore, the FDN itself is compared to the conventional pattern recognition technique based on the feature vector distance, the Euclid distance measure, where the input is taken from the AFEN. The obtained results show that the discrimination accuracy with the HNN is better than that with the other combination of the discrimination method and its input. The output criteria of network for practical use is also discussed. The discrimination accuracy with this criteria is 85.4% and there is no case which mistakes the fault condition for the normal condition. These results suggest that the proposed decision network is effective for the acoustic diagnosis.

An algorithm interpolating parallel cross-sections between CT slices is described. Contours of equiscalar or constant-density surfaces on cross-sections are directly obtained as non-intersecting loops from grayscale slice images. This algorithm is based on a general algorithm that the authors have proposed earlier, constructing triangulated orientable closed surfaces from grayscale volumes and is particularly suited for a new technique, called laser stereolithography, which creates real 3D plastic objects using UV laser to scan and harden liquid polymer. The process of laser stereolithography is executed slice by slice, and this technique really requires some interpolation of intermediate cross-sections between slices. For visualizing, surfaces are only expected to be shaded almost continuously. The local defects are invisible and not cared about if the picture resolution is rather poor. On the contrary, topological faults are fatal to construct solid models by laser stereolithography, i.e., every contour line on cross-sections must be closed with no intersection. Not a single break of a contour line is tolerated. We already have many algorithms available for equiscalar surface construction, and it seems that if we cut the surfaces, then contour lines could be obtained. However, few of them are directly applicable to solid modeling. Marching cubes algorithm, for example, does not ensure the consistency of surface topology. Our algorithm guarantee an adequate topology of contour lines.

The threshold characteristics of mutually coupled SQUIDs (Superconducting Quantum Interference Devices) have been analytically and numerically investigated. The mutually coupled SQUIDs investigated is composed of an rf-SQUID and a dc-SQUID. Here, the rf-SQUID is a flux quantum generator and the dc-SQUID is a flux detector. The linearization method substituting sin-1x by (π/2)x (1x1) is found valid when it is applied to the mutually coupled SQUIDs, because it is possible to obtain the superconducting regions analytically. By computer implementation of linearization method, we found this method is very effective and very quick compared to the ordinary methods. We report the internal flux on an rf-SQUID, the threshold of a dc-SQUID, and that of mutually coupled SQUIDs obtained by Lagrange multiplier formulation and linearization. The features of the threshold characteristics of the mutually coupled SQUIDs with various parameters are also reported. The discontinuous behavior of threshold of the mutually coupled SQUIDs are attractive for digital applications. We suggest three applications of the mutually coupled SQUIDs, that is, a logic gate for high-Tc superconductors (HTSs), a neuron device, and an A/D converter.

The Cooper pairing interaction in high Tc oxide superconductor is discussed in terms of an empirical expression; TcDexp[1/g], gcωo which was derived in our previous investigation. The dual character of this expression consisting of the phonon Debye temperature D and electronic excitation ωo in the mid-infrared region can be interpreted on the basis of the phonon-assisted mechanism on carrier conduction and the electronic excitation. A tunneling spectrum here presented shows certain evidence of the phonon contribution. The characteristics of the long range superconductive proximity phenomena recently reported are also may be interpreted by this mechanism.

Structure and resistivity of BaBiOy were compared with those of Ba1-xLaxBiO3. Decrease in an average Bi valence from 3.91 to 3.03 for BaBiOy leads to an increase in the lattice parameter c from 4.37 to 4.53 , in the unit cell volume from 81 3 to 87 3, and in the resistivity from 10 Ωcm to 2105 Ωcm. It was found that the increase in the unit cell volume and the resistivity was due to change in the average Bi valence. The resistivity of BaBi1-xLaxO3 was compared with that of BaBiOy and Ba1-xLaxBiO3. We also found that pseudocubic Ba1-xLaxBiO3 remains semiconducting as well as pseudotetragonal BaBiOy. The high resistivity in the Ba1-xLaxBiO3 and the BaBi1-xLaxO3 will be useful to the application for the SIS junction.

An adaptive multichannel IIR lattice predictor for k-step ahead prediction is constructed and the effectiveness of the proposed predictor is evaluated using digital simulations.

Digital neural networks are suitable for WSI implementation because their noise immunity is high, they have a fault tolerant structure, and the use of bus architecture can reduce the number of interconnections between neurons. To investigate the feasibility of WSIs, we integrated either 576 conventional neurons or 288 self-learning neurons on a 5-inch wafer, by using 0.8-µm CMOS technology and three metal layers. We also developed a new electron-beam direct-writing technology which enables easier fabrication of VLSI chips and wafer-level interconnections. We fabricated 288 self-learning neuron WSIs having as many as 230 good neurons.

This paper reviews the potential possibility and present status of trans-polyacetylene research toward realization of soliton molecular devices utilizing characteristics of the quasi-one-dimensional conductor. Properties of solitons in polyacetylene are summarized from a point of view to produce a new microelectronics beyond Si-LSI's. The limiting performance of soliton LSI's are roughly estimated. One bit information is stored in only 420 2. The information transmission rate of a wiring is 2104 Gb/s. The delay time per gate is 0.05 ps. For realization of this high performance devices, a lot of research must be carried out in future. A new circuit with new principles of operations must be developed to achieve the performance, where a localized soliton or a localized group of solitons are treated. Some systems, which may lead to development of logic circuits, are proposed. The problems in crystal quality and fabrication process are also discussed and some means against them are presented.

The locally exhaustive testing of multiple output combinational circuits is the test which provides exhaustive test patterns for each set of inputs on which each output depends. First, this paper presents a sufficient condition under which a minimum test set (MLTS) for the locally exhaustive testing has 2w test patterns, where w is the maximum number of inputs on which any output depends. Next, we clarify that any CUT with up to four outputs satisfies the condition, independently of w and n, where n is the number of inputs of the CUT. Finally, we clarify that any CUT with five outputs also satisfies the condition for 1w2 or n2wn.

This paper describes the architecture and simulated performance of a proposed Integrated Memory Array Processor (IMAP). The IMAP is an LSI which integrates a large capacity memory and a one dimensional SIMD processor array on a single chip. The IMAP holds, in its on-chip memory, data which at the same time can be processed using a one dimensional SIMD processor integrated on the same chip. All processors can access their individual parts of memory columns at the same time. Thus, it has very high processor-memory data transfer bandwidth, and has no memory access bottleneck. Data stored in the memory can be accessed from outside of the IMAP via a conventional memory interface same as a VRAM. Since the SIMD processors on the IMAP are configured in a one dimensional array, multiple IMAPs could easily be connected in series to create a larger processor and memory configuration. To estimate the performance of such an IMAP, a system architecture and instruction set were first defined, and on the basis of those two, a simulator and an assembly language were then developed. In this paper, simulation results are presented which indicate the performance of an IMAP in both image processing and artificial neural network calculations.

In this letter, the effectiveness of the quasi-TEM approximation is studied for the microstrip line including optically induced semiconductor plasma region. This approximation is considered to be efficient under several restrictions such as the upper limit of the microwave frequency and the plasma density.

In this paper, we present an efficient method for the fault simulation of the reconvergent fan-out stem. Our method minimizes the fault propagating region by analyzing the topology of the circuit, whose region is smaller than that of Tulip's. The efficiency of our method is illustrated by experimental results for a set of benchmark circuits.

Numerical solutions for the near-field of microstrip antennas are presented. The field distribution is calculated by taking the inverse Fourier transform involving the current distribution with the help of the spectral-domain moment method. A new technique to save the computation time is devised, and the field pattern of the circularly polarized antenna is illustrated.

A speech coding scheme at 3.6 kbit/s has been proposed. The scheme is based on CELP (Code Excited Linear Prediction) with pitch synchronous innovation, which means even random codevectors as well as adaptive codevectors have pitch periodicity. The quality is comparable to 6.7 kbit/s VSELP coder for the Japanese cellular radio standard.

Scaling-down of MOSFETs (metal-oxide-semiconductor field effect transistors can be divided to semi-classical and quantum mechanical one. In the regime of semi-classical scaling-down the behavior of electrons and holes can be well described with the effective mass approximation and in the regime of quantum mechanical scaling-down the characteristics of electrons and holes as wave becomes markedly. The minimum size limit of MOSFETs scaled down in semi-classical regime is mainly determined by the subthreshold characteristics and the short channel effect on the threshold voltage and 0.1 µm will be the minimum channel length from practical viewpoints. Scaling down of MOSFETs enhances their operational speed, but the substrates with high resistivity which are often used in SOI (silicon on insulator) substrates result longer dielectric relaxation time. While the dielectric relaxation time becomes longer than the reciprocal of signal frequency, the semiconductors work as lossy dielectrics and may lead to new types of dynamic circuits. Modification of material properties utilizing the wave nature of electrons is an illustration of quantum mechanical way to improve characteristics of MOSFETs. Suppression of optical phonon scattering of two dimensional electrons by introducing two dimensional array of quantum dots into substrates is expected to improve high field characteristics of material. Brillouin zone folding is another way to control the band structure of materials, especially to make the indirect transition band structure to the direct transition band structure. Heat transfer from a chip severely limits the number of devices which can be integrated on the chip. Reduction of signal charge to electronic elementary charge, that is quantum limit, is expected to be useful for realization of nano-power electronics.

The authors developed new measuring system (Holographic Pattern Measuring System [HPMS]), which is composed of both techniques of holography and graphic image processing, was used to measure the vibrations of a printed circuit board (PCB) due to operation of a mounted electromagnetic relay on it. The clear vibration patterns were obtained. By using pattern analysis processor, quantitative vibration patterns of the PCB surface were observed. Both the vibration patterns and displacements were changed by edge fixing way of the PCB.

We propose a continuous speech recognition algorithm utilizing island-driven A* search. Conventional left-to-right A* search is probable to lose the optimal solution from a finite stack if some obscurities appear at the start of an input speech. Proposed island-driven A* search proceeds searching forward and backward from the clearest part of an input speech, and thus can avoid to lose the optimal solution from a finite stack.