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.

A composite noise generator (CNG) is proposed for simulating the actual non-Gaussian noise and its applications are mentioned. Basing upon the actual measured result (APD) of induced noise from electric contact discharge arc, the APD is approximated by partial linearlization and shown that it can be simulated by a combination of plural Gaussian noise sources. Applying the CNG, quasi-peak (Q-P) detector is investigated and shown that the Q-P detector response is different for non-Gaussian noise when its time domain parameter is different even if its original APD is the same. For digital transmission error due to non-Gaussian noise, and for TV picture stained by the non-Gaussian noise, the CNG is applied to evaluate their performances and quality. The results obtained show that the CNG can be used as a standard non-Gaussian generator for several immunity tests for information equipments.

A permutation cipher scheme using polynomials over a field is presented. A permutation as well as substitution plays a major role in almost all conventional cryptosystems. But the security of the permutation depends on how symbols are permuted. This paper proposes the use of polynomials for the permutation and show that the scheme satisfies the following security criteria. (1) There are enough encryption keys to defend exhaustive attacks. (2) The permutation moves almost all samples into places which are different from the original places. (3) Most samples are shifted differently by different permutations. The permutation cipher scheme could be regarded as a scheme based on Reed-Solomon codes. The information symbols of the codes compose a key of the permutation cipher scheme.

An efficient algorithm is given for finding all solutions of piecewise-linear resistive circuits containing nonseparable transistor models such as the Gummel-Poon model or the Shichman-Hodges model. The proposed algorithm is simple and can be easily programmed using recursive functions.

Electromagnetic environments generated by power transmission system, possibilities of the interference and its mitigation method was introduced. In the frequency region below 10kHz, concern for DC and AC electric and magnetic field are described. In the frequency range above 10kHz, concern for discharges on power apparatus, electromagnetic emvironments generated by carrier system and fault locating system and passive interference are described. Electromagnetic environment caused by load equipments, that is harmonics, and undesirable electromagnetic emission from power converting units are described finally.

An excitation signal for a synthesis filter plays an important role in producing high quality speech at a low bit rate. This paper presents a new efficient excitation model, Adaptive Density Pulse (ADP) , for low bit-rate speech coding. This ADP is a pulse train whose density (spacing interval) is constant within a subframe but can be varied subframe by subframe. First, the ADP excitation signal is defined. A procedure for finding the optimal ADP excitation is presented. Some results on investigating the effects of the ADP parameters on the synthesized speech quality are discussed. ADP excitation is introduced to the CELP (Code Excited Linear Prediction) coding method to improve speech quality at bit rates around 4 kbps. A CELP coder with an ADP (ADP-CELP) is described. ADP excitation makes it possible for the CELP coder to follow transient portions of speech signals. Also ADP excitation can reduce computational complexity in selecting the best excitation from a codebook, which has been the primary drawback of CELP. The number of multiplications can be reduced to the order of 1/D2 by utilizing the sparseness of ADP excitation, where D is the pulse interval. The authors evaluated the speech quality of a 4 kbps ADP-CELP coder by computer simulation. ADP excitation improved the performance of conventional CELP in segmental SNR.

This paper proposes a new approach for the development of a module generator that can parameterize both the size and the structure of layout. The proposed method acquires a design procedure from the design process of a designer, and reuses it to synthesize new layouts with different input parameters that affect the size or the structure of layout. In this method, a designer creates a module layout on a layout editor instead of writing a program. From his design process, a procedure to synthesize the layout is automatically derived. Then, it is generalized so that it could be valid under different values of input parameters. The generalized procedure is independent of design rules, and is capable of synthesizing error-free module layouts of different size and structure. Also, the procedure includes designer's requirements on how the layout should be designed. The experimental results of applying the approach for developing generators of analog device components show effectiveness of our approach.

We propose a new compaction problem that allows layout elements to have many shape possibilities. The objective of the problem is to find not only positions but also shapes of layout elements. We present an efficient method to solve the problem--compaction with shape optimization. This method simplifies the problem by considering the optimization of shapes only for the layout elements on a critical path. The layout is compacted step by step while optimizing the shapes of layout elements. Another importance of this compaction technique is that it makes layout to be "recyclable" for other set of device parameters. The experimental examples, which attempt shape optimization and recycle of analog layout, confirms the importance and efficiency of our method.

A method of driving the effects caused by finite input impedance and nonzero output impedance of functional building blocks into a frequency shift of transfer characteristics is proposed. The method is quite simple and systematic. The input and output impedances can have arbitrary values under a simple condition which meets the monolithic integration of circuits. The effects of non ideal input and output impedances are converted to a change of integrator gain leading to a simple frequency shift of circuits. The frequency shift can easily be adjusted by conventional methods. A typical example shows a remarkable effect of the method.

For symmetric cryptosystems, their transformations should have nonlinear elements to be secure against various attacks. Several nonlinearity criteria have been defined and their properties have been made clear. This paper focuses on, among these criteria, the propagation criterion (PC) and the strict avalanche criterion (SAC), and makes a further investigation of them. It discusses the sets of Boolean functions satisflying the PC of higher degrees, the sets of those satisfying the SAC of higher orders and their relationships. We give a necessary and sufficient condition for an n-input Boolean function to satisfy the PC with respect to a set of all but one or two elements in {0,1}n{(0,...,0)}. From this condition, it follows that, for every even n 2, an n-input Boolean function satisfies the PC of degree n 1 if and only if it satisfies the PC of degree n. We also show a method that constructs, for any odd n 3, n-input Boolean functions that satisfy the PC with respect to a set of all but one elements in {0,1}n{(0,...,0)}. This method is a generalized version of a previous one. Concerned with the SAC of higher orders, it is shown that the previously proved upper bound of the nonlinear order of Boolean functions satisfying the criterion is tight. The relationships are discussed between the set of n-input Boolean functions satisfying the PC and the sets of those satisfying the SAC.

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.

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.

Broadband antennas such as biconical antennas and log-periodic dipole antennas are generally used in automatic EMC measurements. However, these broadband antennas have not been used for accurate measurement because accurate specifications for them are lacking. Therefore, more accurate analysis is urgently required by the CISPR (International Special Committee on Radio Interference), to establish the specifications for broadband antennas for EMC measurements. In this paper, the AF of biconical antennas is calculated by using Moment Methods. The frequency characteristics and antenna height dependency of AF are presented. AF is also measured and compared to the data obtained by the calculations. Good agreement between the calculations and measurements is achieved, indicating the usefulness of our computation method. In addition, the effect of antenna separation distance and transmitting antenna height on AF is investigated. The calculated AF deviation from the reference value is nearly 0dB except for certain antenna arrangements. In these antenna arrangements, the field becomes null at the receiving antenna and widely varies in magnitude and phase around the null points. Therefore, the antenna is immersed in a non-uniform field, while the AF is defined on the assumption of a uniform field. Consequently, the erroneous AF will be derived from measurements around these null points and it will be greatly different from that obtained at other antenna heights. Thus, it is better to avoid these conditions during actual measurements. The effect of the ground plane on AF is also evaluated. AF is shown to be seriously affected by the ground plane especially at frequencies around 90MHz. It should be noted that AF deviation has crests corresponding to the null field at 300MHz. The obtained data will be useful in establishing specifications of biconical antennas for EMC measurements.

A system for measuring the low frequency amplitude and phase noises was set-up, with employing a phase sensitive detector and phase-shifter. It is noted that both noises were partly correlated. The phase noise was explained by the transit time fluctuation due to the fluctuating diffusion coefficient. The amplitude noise reduction was demonstrated by applying the inverted output of the phase noise to the amplitude noise.

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.

Effects of various joint configurations and gap sizes on the electromagnetic shielding effectiveness (SE) are evaluated to provide guidelines for best design of joints in order to increase the value of SE. Four different joint geometries are presented. A sharp decrease on SE with larger gap size for simple joints is observed. Addition of bends in the joint geometry has strong positive effect on the value of the SE. Increasing the angle of cut, which increases the effective length of the joint were also demonstrated to have increasing effect on the shielding performance.

Exploiting the full potential of a multiprocessor system requires a good job scheduling algorithm. In this paper we analyze three dynamic job scheduling algorithms in multiprocessor systems. These algorithms are based on static job scheduling algorithms, LPT (longest processing time first), SJF (shortest job first), and LPR (largest processor requirement first), each of which exhibits good performance in terms of asymptotic upper bound on the makespan of the schedule generated by it. We analyze their performance in the dynamic case experimentally, where we have a stochastic stream of jobs with arbitrary processing time and processor requirement. We compare their performance with the FCFS algorithm and its simple extension. Except for LPT, the algorithms are found to perform significantly better than FCFS, while among themselves SJF performs the best, followed by K-LPR, a variation of LPR. We also consider the fairness aspect of these algorithms and propose a general technique to impose fairness on these algorithms. Finally, we analyze the impact of imposing fairness on the performance of these algorithms.

In this paper, we propose a new class of ID-based non-interactive key sharing scheme with a trusted center which generate a common key on the basis of a linear combination of the center secrets. We also discuss the security of the proposed schemes, and show that the proposed schemes prevent the conventional collusion attack, by adding another random integers unique to each user, on the secret vector that is assigned to the user. Furthermore, we present a new type of a statistical collusion attack which is more suitable for the proposed schemes. We also present the lower bound of the threshold of the statistical collusion attack on the proposed schemes. The proposed schemes can be easily implemented compared with other schemes as they require only computing of the inner product of two vectors over finite ring (including finite field) and an Euclidean quotient, for generating the common key. Our proposed schemes can be regarded as modified versions of the Blom's original scheme. However our proposed schemes are secure against our new type of the attack, as well as the collusion attack based on the solving of the linear equations, although Blom's scheme is insecure against both of these collusion attacks.

The polarization dependence of femtosecond soliton-soliton interactions is investigated in detail. When the polarization direction of two solitons is orthogonal, the soliton interaction can be reduced in comparison to that for parallel polarization. The soliton self-frequency shift (SSFS) is still observed even in the orthogonal condition, but the quantity of the SSFS is much smaller than in the parallel condition. A stronger soliton interaction is observed between two solitons in an in-phase condition, than in an out-of-phase condition. The largest SSFS occurs in-phase with parallel polarization. The polarization dependence of femtosecond soliton interaction in a distributed erbium-doped fiber amplifier (DEDFA) is also investigated. It is shown that when the optical gain of the DEDFA is given adiabatically, the input pulse separation at which the first soliton occurs is less with orthogonal polarization. This is because the soliton pulse width is reduced due to the adiabatic soliton narrowing caused by the optical amplification.

Ultrashort pulsed-beam propagation in a Kerr-type bulk medium is studied theoretically through classical and quantum field solutions of a higher-order nonlinear Schrödinger equation, which is valid for transversely localized femtosecond pulses in an anomalous dispersion regime. Quantum-mechanical stability analysis via a Hartree approximation to interacting bosons shows that within a certain range of a parameter the solitary wave could be stabilized even in the three-dimensional transverse space-time. This feature admits of an exotic route to multidimensional solitons.