We propose a fully digital architecture for Kohonen network suitable for VLSI implementation. The proposed architecture adopts a functional memory type parallel processor (FMPP) architecture which has a structure similar to a content addressable memory (CAM). One word of CAM is regarded as a processing element and a group of elements forms a neuron. All processing elements execute the same operation in bit-serial but in processor-parallel. Thus the number of instructions for realizing the network algorithm is independent of the number of neurons in the network. With reference to a previously reported CAM, we estimate a network with 96 neurons for speech recognition could be integrated on three chips using a 1.2 µm process, and it operates 50 times faster than a sequential hardware. Owing to its highly regular structure of memories, the proposed hardware architecture is well compatible with current VLSI technology.

The design of complex VLSI systems relies more and more heavily on scientific computing for numerical simulation and configuration/performance optimization. Especially, computer simulation is becoming a component of VLSI design methodology, for which a variety of computation evolutions have been accomplished for the past two decades. There are many different forms of simulation which are used for verification of VLSI design at various stages of the whole design process. They may be classified into functional or behavioral simulators, register transfer level (RTL) simulators, gate-level logic, or simply logic, simulators, timing simulator, circuit simulators, device simulator, and process simulators. Among these simulation tasks, a series of logic, timing, and circuit simulation is most strongly related to the design stage which deals with logic/electric waveform performance of VLSI circuits. This article surveys the state of the art of VLSI simulation, putting stress mainly on the domain of logic, timing, and circuit simulation, since the reader of the Transactions may be interested exclusively in this field.

We observed a ship as a radar target embedded in sea clutter using a millimeter wave radar. The shape of the ship and sea clutter were discriminated by using texture analysis in image processing. As a discriminator, a nonlinear transformation of a local pattern was defined to deal with high order statistics.

Correlation between the surface-SAR and external magnetic near-field in a realistic head model for 1.5GHz microwave far-field exposure is described. The regression relation is shown between the one gram averaged SAR and squared external magnetic field on the cross sectional perimeter of the head model.

In our recent work, a forward test generation method for sequential circuits by using a single time frame was proposed. In order to improve the effectiveness of the method, we introduced an extended mode which can handle the two time frames for a hard-to-test fault and a state escaping phase which can detect a sequence of unsuitable states for test generation. The experimental results show that the improved method is effective in generating higher coverage tests with a small number of tests.

This paper deals with study results on the effect of nonlinear amplification in the CDMA system using offset-QPSK signals bandlimited with a square-root cosine roll-off filter. As a result of the study, it is shown that the nonlinear amplification does not affect bit error rate performance with reasonable out-of-band emission characteristics when the roll-off factor of the transmit filter is one.

In this letter, a new structure of adaptive IIR notch filter is presented. The structure is based on direct form realization and uses the similar adaptation algorithm given in Ref. (4). A quantitative analysis for convergence properties is developed. It is shown that the proposed structure shows superior performance comparing with previously proposed designs. The results of computer simulations are presented to substantiate the analysis.

This letter proposes an LSP quantizing method which uses interframe correlation of the parameters. The quantized parameters are represented as a moving average of code vectors. Using this method, LSP parameters are quantized efficiently and the degradation of decoded parameters caused by bit errors affects only a few following frames.

The matrix whose eigenvectors are the basis vectors of the DCT is introduced. This matrix leads to a convolution-product property using the DCT. Based on the property, the parameter of uniform blur, such as motion blur or out-of-focus blur, is estimated from the local minima of the DCT energy spectrum of a blurred image. Computer experiments confirmed that the DCT is superior to the DFT for estimating the parameter.

This letter proposes a new routing strategy and a design of ATM switches. By partitioning internal links into subgroups based on the bandwidth of a connection request, an ATM switching network which is nonblocking in the wide sense at the connection level can be constructed without the need of internal-link speedup.

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 new type jacket cutter for optical fibers is designed, and it is confirmed experimentally that its performance is superior to those of the conventional cutters. Using this new cutter which is mainly consisted of a rotatable fiber holder and a pair of blades separated by a distance of 0.3-0.4mm, only the tight jacket is cut and removed while the primary coating and the fiber are kept intact. As the result, the probability of damage to the fiber surface during jacket removal is reduced to about 0% compared to 10% found in the case of a conventional cutter. This result is useful to increase the reliability of optical fibers during assembling efforts.

The singular point analysis, such as the Painlev test and Yoshida's test, is a computational method and has been implemented in a symbolic computational manner. But, in applying the singular point analysis to high dimensional and/or "complex" dynamical systems, we face with some computational difficulties. To cope with these difficulties, we propose a new numerical technique of the singular point analysis with the aid of the self-validating numerics. Using this technique, the singular point analysis can now be applicable to a wide class of high dimensional and/or "complex" dynamical systems, and in many cases dynamical properties such as the algebraic non-integrability can be proven for such systems.

Japan's PARTNERS Project, one of the programmes of ISY advocated by UN, has just started. This letter is a brief introduction of the trials being carried out by the partners in the University of Electro-communications under the Project. The focus is on the distance education and training via ETS-V overcoming the geographical extent and the cultural diversity of the Asia-Pacific Region.

A shift down of the resonance frequency is claimed to be used as a simple practical test for the onset of chaos based on a common feature of forced damped nonlinear oscillation systems which exhibit cascading bifurcations to chaos.

In a file transmission net N with vertex set V and arc set B, copies of a file J are distributed from a vertex to every vertex, subject to certain rules on file transmission. A cost of making one copy of J at each vertex µ is called a copying cost at µ, a cost of transmitting one copy of J through each arc (x, y) is called a transmission cost (x, y), and the number of copies of J demanded at each vertex u in N is called a copy demand at u. A scheduling of distributing copies of J from a vertex, say s, to every vertex on N is called a file transfer from s. The vertex s is called the source of the file transfer. A cost of a file transfer is defined, a file transfer from s is said to be optimal if its cost is not larger than the cost of any other file transfer from s, and an optimal file transfer from s is said to be optimum on N if its cost is not larger than that of an optimal file transfer from any other vertex. In this note, it is proved that an optimal file transfer from a vertex with a minimum copying cost is optimum on N, if there holds M U where M and U are the mother vertex set and the positive demand vertex set of N, respectively. Also it is shown by using an example that an optimal file transfer from a vertex with a minimum copying cost is not always optimum on N when M ⊃ U holds.

Embossed disks with discrete magnetic tracks and servo marks are proposed and evaluated. The tracks and the servo marks are made by etching the glass substrate. The guard band depth was decided to be 0.2 µm. Using the disks, the head positioning accuracy of 0.09µm (rms) and the recording density of 192 tracks per millimeter were demonstrated.

We discuss possible new principles of information processing by utilizing microscopic, semi-microscopic and macroscopic phenomena occuring in nature. We first discuss quantum mechanical universal information processing in microscopic world governed by quantum mechanics, and then we discuss superconducting phenomena in a mesoscopic system, especially an information processing system using flux quantum. Finally, we discuss macroscopic self-organizing phenomena in biology and suggest possibility of self-organizing devices.

Sea clutter was measured using an X-band radar at very high grazing angles between 8.2 and 17.5. The sea state was 7 with the wave height of 6 to 9m. The wind velocity was 25m/s. It is shown that sea clutter amplitudes obey the log-normal and K distributions using the Akaike Information Criterion (AIC) , which is more rigorous fit to the distribution to the data than the least squares method.

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.