We developed a method for analysis of boron penetration and gate depletion using N+ and P+ dual-gate PMOSFETs. An N+ gate PMOSFETs, which is immune to boron penetration and gate depletion, exhibited the threshold voltage shifts and fluctuation in P+ gate PMOSFETs fabricated using identical N- substrates. We showed the importance of Vth fluctuation analysis and found that the Vth fluctuation in N+ gate PMOSFETs was negligible, but, the Vth fluctuation in P+ gate PMOSFETs was significant, indicating that the Vth fluctuation in P+ gate PMOSFETs was dominated by boron penetration. It was also shown, for the first time, that boron penetration occurred with gate depletion, and gate depletion must be very strong to suppress boron penetration. The dual-gate PMOSFET method makes it possible to select high-performance G-bit DRAM fabrication processes that are robust against Vth fluctuation.

A high quality speech synthesis technique based on the wavelet subband analysis of speech signals was newly devised for enhancing the naturalness of synthesized voiced consonant speech. The technique reproduces a speech characteristic of voiced consonant speech that shows unvoiced feature remarkably in the high frequency subbands. For mixing appropriately the unvoiced feature into voiced speech, a noise inclusion procedure that employed the discrete wavelet transform was proposed. This paper also describes a developed speech synthesizer that employs several random fractal techniques. These techniques were employed for enhancing especially the naturalness of synthesized purely voiced speech. Three types of fluctuations, (1) pitch period fluctuation, (2) amplitude fluctuation, and (3) waveform fluctuation were treated in the speech synthesizer. In addition, instead of a normal impulse train, a triangular pulse was used as a simple model for the glottal excitation pulse. For the compensation for the degraded frequency characteristic of the triangular pulse that overdecreases than the spectral -6 dB/oct characteristic required for the glottal excitation pulse, the random fractal interpolation technique was applied. In order to evaluate the developed speech synthesis system, psychoacoustic experiments were carried out. The experiments especially focused on how the mixed excitation scheme effectively contributed to enhancing the naturalness of voiced consonant speech. In spite that the proposed techniques were just a little modification for enhancing the conventional LPC (linear predictive coding) speech synthesizer, the subjective evaluation suggested that the system could effectively gain the naturalness of the synthesized speech that tended to degrade in the conventional LPC speech synthesis scheme.

The Tropical Rainfall Measuring Mission (TRMM) is a United States-Japan joint project to measure rainfall from space. The first spaceborne rain radar is aboard the TRMM satellite. Rain/no-rain discrimination for the TRMM provides useful information for on-line data processing, storage, and post-processing analysis. In this paper, rain/no-rain discrimination for the TRMM has been validated through simulation and theory for the no-rain condition and by comparison with the ground-based radar data for rain conditions.

Elliptic curves Em: By2 = x3+Ax2+x are suitable for cryptographic use because fast addition operations can be defined over Em. In elliptic curve cryptosystems, encryption/decryption involves multiplying a point P on Em by a large integer n. In this paper, we propose a fast algorithm for computing such scalar multiplication over Em. The new algorithm requires fewer operations than previously proposed algorithms. As a result, elliptic curve cryptosystems based on Em can be speeded up by using the new algorithm.

In any ill-conditioned information-transfer system, as in long-distance communication, we often must construct feedback confirmation channels, in order to confirm that informations received at destinations are correct. Unfortunately, for such systems, undesirable uncertain fluctuations may be induced not only into forward communication channels but also into feedback confirmation channels, and it is such difficult that transmitters always confirm correct communications. In this paper, two fuzzy-set-valued mappings are introduced into both the forward communication channel and the feedback confirmation channel, separately, and overall system-behaviors are discussed from the standpoint of functional analysis, by means of fixed point theorem for a system of generalized equations on fuzzy-set-valued mappings. As a result, a good mathematical condition is successfully obtained, for such information-transfer systems, and fine-textured estimations of solutions are obtained, at arbitrary levels of values of membership functions.

In this paper, we consider the coherent radar detection of rapid fluctuating signals in the Gaussian noise. This problem has been previously solved by employing the GLR technique, but we use the ALR to improve the detection performance. So, after deriving an approximate ALR detector, we compare the new detector with the GLR and Square-law detectors and we show its superiority.

This paper describes experimental results of the IP traffic condition based dynamic optical path allocation network system. In the system, optical paths are dynamically allocated between congested node pairs to cope with traffic fluctuations. It seems that this experiment is the first of its kind in the world.

As technology moves at an annual area density increase rate of 80-120% and channel density moves beyond 3, micro-fluctuation of media recording performance and the homogeneity of media's recording capability become serious reliability concerns in future high density magnetic recording systems. Two concepts are proposed in this work for the characterization of the micro-recording performance fluctuation at high bit and channel densities: recording performance roughness analysis and dynamic magnetic roughness analysis. The recording performance roughness analysis is based on an in-situ measurement technique of the non-linear transition shift (NLTS). Relationship between the performance roughness and the roughness of dynamic magnetic parameters are studied. Results of experimental investigations indicate that the NLTS based performance roughness analysis can reveal more details on media's recording capability and the capability fluctuation--the macro and micro fluctuation of recording performance. The dynamic magnetic roughness analysis is read/write operation based and can be used to characterize the macro and micro fluctuation of media's dynamic magnetic properties. The parameters used for the analysis include media's dynamic coercivity and the dynamic coercive squareness. Here, "dynamic" refers to the dynamic performance measured at MHz frequency. The authors also noticed in their technology development process that further methodology development and confirmation are necessary for media's dynamic performance analysis. Therefore, the work also extends to the accuracy analysis of the playback amplitude based methods for the analysis of the dynamic coercive squareness and dynamic hysteresis loop. A method which is of smaller testing error is identified and reported in this work.

We investigate the intrinsic current fluctuations in small Si-MOSFETs via the Monte Carlo device simulation. It is demonstrated that the temporal fluctuation of the drain current in Si-MOSFETs attains a significant fraction of the averaged drain current when the device width is scaled down to the deep sub-µm regime. This is caused by the drastic decrease in the number of channel electrons. This finding holds true whenever the device width is reduced to deep sub-µm, regardless of the channel length. Most importantly, current fluctuation is associated with the quasi-equilibrium thermal noise in the heavily-doped source and drain regions, whereas its magnitude with respect to the averaged drain current is directly related to the number of channel electrons underneath the gate.

This paper describes how voltage fluctuation in the DC power supply of a digital IC can be reduced, by means of molding the package-pin in a ferrite-resin composite. The voltage fluctuation of the DC power supply, when the input terminal was driven by a 40 MHz, 5 Vp-p pulse wave, was measured using an oscilloscope. Simultaneously, the voltage spectrum of the fluctuation was measured using a spectrum analyzer. As a result, the voltage fluctuation was decreased by about 50 % when the IC package-pins were molded in a ferrite-resin composite, in which the µiac of the ferrite powder equalled 100, and the powder content was 80 weight-%. In the same IC, there was the reduction effect of the voltage spectrum of the fluctuation was recognized in the frequency range 40 MHz to 1 GHz.

The noise level distribution owing to only a non-stationary working objective machine has been stochastically expressed by reflecting the temporal change of distribution parameters under a generalized regression model especially with aid of the vibration level observation. The proposed method has been applied to a noise evaluation of non-stationarily operated jigsaw.

In multi-media systems, the type of interactive communication channels is found almost everywhere and plays an important role, as well as the type of unilateral communication channels. In this report, we shall construct a fluctuation theory based on the concept of set-valued mappings, suitable for evaluation, control and operation of interactive communication channels in multi-media systems, complicated and diversified on large scales. Fundamental conditions for availability of such channels are clarified in a form of fixed point theorem for system of set-valued mappings.

Fluctuation characteristics of character centroid intervals in laterally written Japanese sentences are investigated by means of their spatial frequency characteristics. Power spectra of character centroid intervals in their longitudinal and transverse directions are obtained for handwritten and word processor printed sample sentences. It is shown that for fluctuation characteristics in the longitudinal direction, power spectra are inversely proportional to their spatial frequencies for handwritten sentences and proportional to them for word processor printed sentences, and there exists a remarkable difference between handwritten and word processor printed sentences. It is also shown that for fluctuation characteristics in the transverse direction, power spectra are proportional to their spatial frequencies for both handwritten and word processor printed sentences, and there is no remarkable difference between handwritten and word processor printed sentences.

Layout has strong influence on matching properties of a circuit. Current matching models, which characterize both local random non-uniformities and global systematic non-uniformities stochastically, are not adequate for the matching analysis taking the effect of layout realization into account. In order to consider topological information of layout into matching analysis, we propose a matching model which treats the random and systematic components separately. Also, we characterize the micro-loading effect, which modulates fabricated line-width according to the local density of layout patterns, into matching analysis. With these two techniques, we can perform matching analysis of CMOS circuits taking layout information into account.

The naturalness of normal sustained vowels is considered to be attributable to the fluctuations observed in the steady part where speech signal is seemingly almost periodic. There always exist two kinds of involuntary fluctuations in the steady part of sustained vowels, even if the sustained vowels are phonated as steadily as possible. One is pitch period fluctuation and the other is waveform fluctuation. In this study, frequency analyses on these fluctuations were conducted in order to investigate their general characteristics. The results of the analyses suggested that the frequency characteristics of the fluctuations were possible to be approximated as 1/fβ-like, which is regarded as the specific feature of random fractal. Therefore, a procedure based on random fractal generation methods was proposed in order to produce these fluctuations for the improvement of the voice quality of synthesized sustained vowels. A series of psychoacoustic experiments was also conducted to evaluate the proposed technique. Experimental results indicated that the proposed technique was effective for synthesized sustained vowels to be perceived as human-like. Unlike the sustained vowels which were synthesized without pitch period fluctuation nor waveform fluctuation, the synthesized sustained vowels which contained the fluctuations were not perceived as buzzer-like, which is the major problem of the voice quality of synthesized sustained vowels. However, it was also found that both of the fluctuations were not always the acoustic cues for the naturalness of normal sustained vowels. The synthesized sustained vowels which contained the fluctuations whose frequency characteristics were the same as that of white noise were perceived as noise-like, which is not at all the voice quality of normal sustained vowels. The results of psychoacoustic experiments indicated that the frequency characteristics of the fluctuations, which are possible to be modeled as 1/fβ-like, were the significant factors for the naturalness of normal sustained vowels.

An elastic-Vt CMOS circuit is proposed which facilitates both high speed and low power consumption at low supply voltages. This circuit permits fine-grain power control on each multiple circuit block composing a chip, and it is not sensitive to design factors as device-parameter deviations or operating-environment variations. It also does not require any such additional fabrication technology as triple-well structure or multi-threshold voltage. The effectiveness of the circuits design was confirmed in applying it to specially fabricated 16-bit adders and 4-kb SRAMs based on 1. 5-V, 0. 35- µm CMOS technology.

The electromagnetic interference (EMI) induced by steady arc has been demonstrated to be dependent on arc voltage fluctuation when the arc transfers from the metallic phase to the gaseous phase. In order to give the physical understanding of this arc voltage fluctuation and EMI, several typical materials, such as Ag, Cu and Zr, were tested and their arc behavior was determined and compared. The experimental results indicated that the arc behavior, in particular the arc voltage fluctuation in the moment that metallic phase transfers to the gaseous phase was different for different materials. Based on the test results and former investigations, a plausible mechanism is proposed for understanding these phenomena.

Recently, Smith and Lennon proposed a new public key cryptosystem, called LUC, which uses the Lucas function as the one-way function in their cryptographic mechanisms instead of using the exponentiation function. They conjectured that LUC is cryptographically stronger than RSA in 1993. Since then, many weaknesses of LUC have been discoverd, e. g., similar to RSA, LUC also suffers from the chosen-message attacks and the evaluation in LUC is slightly less efficient than that in RSA. In this paper, we analyze another possible weakness of LUC that was not pointed out before. We show that the number of messages which cannot be concealed in LUC is at least as the same as that in RSA regardless of the choice of public keys. In particular, in many cases, the number of messages which cannot be concealed in LUC is greater than that in RSA. This implies that the choice of public keys in LUC needs more limitations than that used in RSA. Our results are useful to designers who consider to use LUC type systems.

This paper reports the thermal stability of particulate media, which include Co-Fe oxide, CrO2, and thick and thin MP tapes. By measuring the time decay of magnetization at room temperature, fluctuation fields were obtained as a function of reverse applied field. It was clarified that the fluctuation field has a constant and minimum value when the reverse applied field is equal to coercivity. Minimum fluctuation fields for the four particulate tapes were measured at several environmental temperatures ranging from -75 to +100. It was also clarified that the fluctuation field normalized by remanence coercivity increases as the environmental temperature increases for all tapes, indicating that it is a good measure of thermal stability. Activation volumes were also deduced as a function of temperature.

This work presents a further development of the approach to modelling thermal (i.e. carrier-velocity-fluctuation) noise in semiconductor devices proposed in papers by the present authors. The basic idea of the approach is to apply classical theory of Ito's stochastic differential equations (SDEs) and stochastic diffusion processes to describe noise in devices and circuits. This innovative combination enables to form consistent mathematical basis of the noise research and involve a great variety of results and methods of the well-known mathematical theory in device/circuit design. The above combination also makes our approach completely different, on the one hand, from standard engineering formulae which are not associated with any consistent mathematical modelling and, on the other hand, from the treatments in theoretical physics which are not aimed at device/circuit models and design. (Both these directions are discussed in more detail in Sect. 1). The present work considers the bipolar transistor compact model derived in Ref. [2] according to theory of Ito's SDEs and stochastic diffusion processes (including celebrated Kolmogorov's equations). It is shown that the compact model is transformed into the Ito SDE system. An iterative method to determine noisy currents as entries of the stationary stochastic process corresponding to the above Ito system is proposed.