Telecommunication services are expected to be upgraded from POTS to B-ISDN services in the future. This means that the conventional metallic access networks should be upgraded to optical fiber access networks because of providing high bit-rate services. Therefore, it is very important to clarify upgrade strategies in access networks. This paper proposes a dynamic evaluation method that can support decision-making on the upgrade strategy from the viewpoint of economy. This method can determine the most promising future access network and upgrade timing. Moreover, viability of various upgrade strategies can be evaluated by this method.

A key element in the CDMA transmission is DS spreading. Spreading in a DS/SSMA system are provided in two categories-synchronization and data. For synchronization sequences, good auto-correlation and cross-correlation properties are required in order to guarantee fast acquistion with a minimum false alarm probability. On the other hand, the auto-correlation property may not be so important in data spreading since synchronization is obtained by synchronization spreading. In this paper we provide a set of synchronization sequences and a set of data sequences--each a set of binary N-tuples--that have the necessary correlation constraints.

This paper proposes a universal structure for STM-N(N=1, 2, 3, ) multiplex line terminals that only utilizes N chips CMOS LSIs for Section OverHead (SOH) processing. The uniquely configured LSIs are applicable to any STM-N line terminal equipment. Reasonable frame alignment performance attributes, such as the maximum average reframe time, false in-frame time, out-of-frame detection time, and misframe time, are calculated for the configuration. A prototype SOH processing LSI built on 0.8m BiCMOS technology successfully realizes the functions needed for multiplex section termination. The STM-64 frame is also demonstrated using the proposed circuit configuration and prototype LSIs.

A black membrane is a biological-membrane analogue, i.e. a phospholipid bilayer membrane, artificially formed on an orifice immersed in water. It is used to investigate the properties of the membrane itself and channels embedded therein. In this paper, microfabrication techniques are applied to fabricate the orifice, and a glass substrate is isotropically etched to define the orifice geometry. The periphery of the orifice was patterned with aminosilane to anchor the membrane. The remainder part was coated with fluorosilane to make the surface hydrophobic and to prevent adsorption of channel-forming molecules. We demonstrated experimentally that a stable and reproducible membrane is easily obtainable using the orifice.

In this paper, a design of TCM signals for Middleton's class-A impulsive noise environment is investigated. The error event characteristics under the impulsive noise is investigated, and it is shown that the length of the signal sequence is more important than Euclidean distance between the signal sequences. Following this fact, we introduce the shortest error event path length as a measure of the signal design. In order to make this value large, increasing of states of convolutional codes is employed, and the performance improvement achieved by this method is evaluated. Numerical results show the great improvement of the error performance and conclude that the shortest error event path length is a good measure in the design of TCM signals under impulsive noise environment. Moreover, the capacity of class-A impulsive noise channel is evaluated, and the required signal sets expansion rates to obtain the achievable coding gain is discussed.

This paper proposes a constructive linearization method for transistor circuits based on a polynomial representation of nonlinear transfer functions. The nonlinear transfer functions for various configurations have been shown in a polynomial form. Then the results have been applied to several bipolar transistor circuits to exemplify the proposed designing method.

This paper describes an efficient slew rate enhancement technique especially suitable for an operational amplifier used in an LCD driver IC. This technique employs an input-dependent biasing without directly monitoring an input; instead, monitoring an output of the first stage of the amplifier. This enhancement technique is easily applied to a conventional two-stage operational amplifier and requires only 8 additional transistors to increase slew rates for both rising and falling edges. The bias currents of the first and the second stages are simultaneously controlled by this biasing. Experimental operational amplifiers with and without this enhancement have been fabricated to demonstrate the improvement of slew rate. Slew rates of 12.5V/µsec for the rising edge and 50V/µsec for the falling edge with a 100 pF load capacitance have been achieved by this technique, compared with slew rates of 0.3V/µsec for the rising edge and 5V/µsec for the falling edge in the conventional amplifier.

In this letter, we propose a simple voltage controlled oscillator (VCO) with circuitry combining a Miller integrator and an RS flip-flop circuit. With the VCO, the control voltage can be varied over a broad range, and the oscillation frequency varies in proportion to the control voltage. The maximum voltage is up to 1000 times the minimum, and the calculated design values and measured values agree well. This VCO can be applied to FM modulators, FSK modulators, and other systems.

This paper describes an advanced rule-embedded neural network (RENN+) that has an extended framework for achieving a very tight integration of learning-based neural networks and rule-bases of existing if-then rules. The RENN+ is effective in pattern recognition with ill-posed conditions. It is basically composed of several component RENNs and an output RENN, which are three-layer back-propagation (BP) networks except for the input layer. Each RENN can be pre-organized by embedding the if-then rules through translation of the rules into logic functions in a disjunctive normal form, and can be trainded to acquire adaptive rules as required. A weight-modification-reduced learning algorithm (WMR) capable of standard regularization is used for the post-training to suppress excessive modification of the weights for the embedded rules. To estimate the effectiveness of the proposed RENN+, it was used for pattern recognition in a radar system for detection of buried pipes. This trial showed that a RENN+ with two component RENNs had good recognition capability, whereas a conventional BP network was ineffective.

The analysis of the shielding properties of chiral materials slabs is here presented, first deriving the spectral representation of the shielded fields, then getting the asymptotic expression of the transmission matrix in the higher frequencies. The time response of the shielded field for the NEMP incidence is finally deduced in a closed form.

In this paper, a new off-line handwritten word recognition method based on the explicit modeling of character junctures is presented. A handwritten word is regarded as a sequence of characters and junctures of four types. Hence both characters and junctures are explicitly modeled. A handwriting system employing hidden Markov models as the main statistical framework has been developed based on this scheme. An interconnection network of character and ligature models is constructed to model words of indefinite length. This model can ideally describe any form of hamdwritten words including discretely spaced words, pure cursive words, and unconstrained words of mixed styles. Also presented are efficient encoding and decoding schemes suitable for this model. The system has shown encouraging performance with a standard USPS database.

It has become very important to study the lightning surges that were induced in subscriber telecommunication equipment because of the increase of susceptible circuits to the over voltage. The test generator is desire to be developed evaluating the resistibility of equipments against lightning surges. This paper proposes a new lightning-test method for subscriber telecommunication equipment. The waveform of the test generator simulates that of the induced lightning surge voltage caused by a nearby return stroke. The output impedance of the surge generator is determined to match the common-mode impedance of telecommunication lines. The damaged condition of circuit parts and the trouble occurrence rate estimated by using this method agree well with actual observations.

Results of an empirical investigation of the shielding properties of a small pre-fabricated reinforced concrete building are presented. The electric field attenuation was measured in the frequency range of approximately 20kHz to 500MHz. The experiments were performed in collaboration with the Italian National Board of Post an Telecommunications (ISPT). An equivalent stick model has been analyzed in frequency domain by numerically solving a set of electric field integral equations. The influence of the real reinforcement mesh (dimensions, spatial disposition, electrical parameters) on the attenuation of the electric field has been investigated. A comparison between computed and measured results is presented.

In this letter, we demonstrate an experimental CMOS neural circuit towards an understanding of how particular computations can be performed by a T-Model neural network. The architecture and a digital hardware implementation of the learning T-Model network are presented. Our experimental results show that the T-Model allows immense collective network computations and powerful learning.

A light, thin and flexible applicator using a microstrip patch array for microwave heating is presented and tested in this work. The applicator is made of a flat silicone rubber bag, inside of which flows cooling water. EM coupling feeding is applied, which has no direct contact between the feed and the patch, to improve durability and reliability when it is repeatedly applied to the uneven surface of the heated portion of the human body. Simulations of SAR distribution are performed using the finite difference time domain (FD-TD) method. Simulated data are compared with the experimental ones using cubic and cylindrical phantom models with single and multielement patch applicators. Simulations of temperature distribution are also performed using the heat transfer equation. Simulated data are compared with the experimental ones using cubic and cylindrical phantom models. The simulated results agree well with the experimental ones. The results obtained here show that the multielement flexible microstrip patch applicator which operates at 430MHz can heat a relatively shallow and widespread area on the human body for hyperthermia treatments.

This paper describes, based on generation mechanism of conductive noise, that the real conductive noise on AC-mains can't be measured by LISN and 50 Ω-input impedance instrument specified by regulations such as CISPR. Second, it is pointed out that one of the causes of poor reproducibility in radiated emission measurement is the difference among line impedances of AC-mains. Finally, it is insisted that the apparatus such as LISN is necessary for stable measurement of radiated emission, and what improvement on LISN characteristics for higher frequency range should be done is introduced.

For estimating the radiated emission from a metallic enclosure, the authors have developed a numerical computational method which applied inverse analysis. A metallic enclosure containing a loop antenna was set up to be a model source for the numerical analysis. Magnetic fields around the enclosure were measured by measurement systems fabricated in the authors' laboratory. Using the measured magnetic fields, current distributions on the enclosure surface were determined by means of an inverse analysis utilizing the least squares method. From this surface current distribution, the electromagnetic field distributions were estimated by forward analysis on a cylindrical surface 3.0m in radius. The amount of the error in the estimated fields distribution was also discussed.

It is shown by the derivation of solution methods for an elementary optimization problem that the stochastic relaxation in image analysis, the Potts neural networks for combinatorial optimization and interior point methods for nonlinear programming have common formulation of their dynamics. This unification of these algorithms leads us to possibility for real time solution of these problems with common analog electronic circuits.

The precise phase characteristics of the reflected and transmitted waves are obtained for electromagnetic scattering by inductive discontinuities of finite thickness located in rectangular waveguides. The incident wave is assumed to be the dominant mode, and the modified residue-calculus method is used for numerical analysis. The phase characteristics when the thickness and width of the iris are varied, and characteristics of the reflected and transmitted waves when resonance appears, are discussed. In addition, an X-band experiment is performed and the calculations for both the reflected and transmitted waves are shown to agree well with the experimental values.