bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two types of speech compression systems using inverse filter codebook
Authors: Matsuyama Yasuo 
Published: July 2007

AbstractTwo types of speech compression systems which use a set of precalculated inverse filters (the inverse filter codebook) are studied. The information theoretic ideas of universal coding and block quantization motivated the use of the inverse filter code‐book. The first system finds the indices of the best matching inverse filter, the gain and the pitch interval for each frame of the input speech signal. In this case, a system operating at 800 bit/s for speech sampled at 8 kHz is adopted as the basic system. The second system is a waveform encoder which uses the inverse filter code‐book and tree searching. The system uses a single tree search, which is an improved version of the parallel tree search presented by the author, and a system of 8,875 bit/s is adopted as the basic device. Application of the inverse filter codebook is effective in achieving rate reduction and/or decreasing the system complexity.The first system falls into the class of vocoders and the second is a waveform encoder. The data rates of the two differ considerably, yet both types of systems are necessary. An example explaining this fact is also given in the text.
Scattering of a plane electromagnetic wave by a thick lossy dielectric slab
Authors: Aoki Kazuo , Uchida Kazunori 
Published: July 2007

AbstractScattering of a plane wave (E wave) by a thick lossy semiinfinite dielectric slab with conductivity σ is evaluated by Fourier transform. The formal solution of the scattered field is derived by the Wiener‐Hopf method. The result is applicable to the cases of lossless media (σ = 0) and perfect conductors (σ → ∞). The scattered far field is evaluated by the saddle point method. The integral along the branch‐cut in the formal solution is evaluated numerically and the effects of the medium loss, slab thickness, and the incident angle on the scattered far field are examined.
Soft error in MOS dynamic RAM
Authors: Yoshihara Tsutomu , Takano Satoshi , Nakano Takao 
Published: July 2007

AbstractAs the degree of integration increases and the power supply voltages decrease in MOS dynamic RAM's, soft errors become increasingly important and need to be studied from the points of view of circuit, process and device technology. In this paper, analytical and experimental studies are conducted on the soft errors of 64‐Kbit dynamic RAM's. First, the relation between the device parameters and the critical charge is examined. If the charge distribution collected in the silicon substrate is Gaussian, the soft error rate is expressed as a complementary error function of the critical charge and agrees well with the experimental results conducted by the use of 241 Am. To improve the soft error, we studied the use of Hi‐C cell structures for increased critical charges and reduced charge collection area by employing polysilicon bit lines and boosted word lines before operation of the sense amplifier. Compared with conventional structures, the critical charge is increased 1.8 times and the collection area reduced to less than half. As a result, the soft error is improved by 700 times and the chip itself is less susceptible to soft error.
Evaluation of pattern registration accuracy in X‐ray lithography
Authors: Okabe Masahiro , Furukawa Yasuo , Inagaki Takefumi 
Published: July 2007

AbstractIn the conventional X‐ray lithographic system using the proximity printing technique by a divergent X‐ray from a point source, it is difficult to analyze the mismatch of overlapping patterns. In this paper, a statistical technique for analyzing and evaluating the performance of a mask aligner and pattern configuration accuracy of masks is proposed. When this technique is applied to an X‐ray lithographic system, the accuracy of the aligner increases to about 0.1 ym (2α) and the distortion of the silicon‐polyimide complex mask becomes about 0.2 ym (2α).
Temperature dependence of SAW dispersive delay lines
Authors: Shimizu Yasutaka , Nakata Taku , Yamamoto Yasushi 
Published: July 2007

AbstractThe SAW dispersive delay line is used extensively for signal processing, such as pulse compressor and spread spectrum system. In the filter and delay line using the ordinary interdigital transducer, the temperature coefficients of the delay time, phase and frequency are identical and depend on the substrate material. In this paper, we discuss the SAW dispersive delay line whose temperature coefficients of the delay time, phase and frequency are dependent on the substrate material and the frequency‐dispersive characteristics. The temperature characteristics can be improved by optimizing the dispersion characteristics. The zero temperature coefficient can be realized even if the substrate temperature coefficient is impractical. The design of the dispersive delay line is proposed with consideration of the temperature characteristics.
Quality improvement of synthesized speech in noisy speech analysis‐synthesis processing
Authors: Nagabuchi Hiromi , Kobayashi Tsutomu 
Published: July 2007

AbstractSpeech analysis‐synthesis is an effective method for low bit‐rate speech coding. However, it has been pointed out that system performance degrades as noise is added to the input speech. In this paper, we describe a method of improving the quality of noise‐de‐graded synthesized speech by using noise reduction methods which are based on the previously proposed comb filtering in the frequency region for the case that the noisy speech signal is processed by the PARCOR analysis‐synthesis method.Quality degradation of synthesized speech due to additive noise is caused mainly by an increase in spectral distortion. In the speech analysis method proposed in this paper, the basic frequency (pitch) of the speech is stably extracted from noisy speech and spectral distortion is eliminated by obtaining the spectral envelope parameter after reducing the noise from the input speech based on this pitch information. Furthermore, the proposed method prevents degradation of the quality of the synthesized speech by using the extracted pitch as the pitch parameter of the analysis‐synthesis system. As a result of auditory experiments, it is shown that the subjective speech quality and intelligibility of the synthesized speech are improved by the proposed method. In addition, we obtain some clues to the configuration of a speech analysis‐synthesis system which is resistant to additive noise.
Synthesis of circular polarization with nonresonant slots in the narrow wall of a rectangular waveguide
Authors: Seki Hajime , Goto Naohisa 
Published: July 2007

AbstractFor a planar array antenna consisting of stacked slotted waveguides a circular polarization created by a slot pair on the narrow wall is proposed. The pair configuration satisfying the circular polarization condition is theoretically determined. It is necessary to accurately obtain the mutual coupling between slots. A formulation for the coupling is given as a boundary value problem. We first derive simultaneous integral equations for the aperture electric field in each slot. Next, solving these equations numerically, we find the effect of mutual coupling quantitatively. In the formulation process, the wall thickness of the waveguide is considered, unlike other analyses, which neglect the thickness. It is found that the effect of finitely thick walls is not negligible. To confirm the validity of the pair arrangement determined by the present analysis, experiments are performed with WRJ 3 waveguides for the S band and an almost perfect circular polarization of axial ratio 0.98 (−0.2 dB) is obtained.
Propagation characteristics of the dominant mode in tunnels with elliptical cross section
Authors: Yamaguchi Yoshio , Abe Takeo , Shimizu Tomio 
Published: July 2007

AbstractThis paper seeks to obtain basic knowledge of the wave propagation characteristics for radio communication in tunnels or subways. The problem of a hollow cylinder surrounded by a lossy medium is modeled and the propagation characteristics of the dominant mode, which is most important in practice, are rigorously obtained. For a medium of elliptical cross section with high conductivity, the propagation characteristics can be calculated by a perturbation method, whereas for those media with low conductivity, such as concrete and rock, this method fails. Herein the governing characteristic equation for the propagation constant is derived and the constant is calculated numerically.Since the elliptical cross section has two symmetric axes, there exist odd and even dominant modes. It is shown numerically that in the hollow elliptical cylinder in an actual tunnel, the two attenuation constants for the two modes decrease with frequency and that the odd mode attenuation is less than that of the even mode. The attenuation is also investigated with respect to the medium constants and is found to be dependent more on the dielectric constant than conductivity. Also, measurement of attenuation according to the modeled experiment is found to be in good agreement with the analytical results.
Analysis of a class of free electron laser using a periodic static magnetic field
Authors: Shiozawa Toshiyuki 
Published: July 2007

AbstractWith the aid of coupled mode theory, this paper clarifies quantitatively the oscillation mechanism of the free electron laser in the submillimeter and far infrared wave region which is composed of a relativistic electron beam and periodic static magnetic field. First, on the basis of Maxwell's equations, the relativistic equation of motion for the electron and the equation of continuity for electrons, the coupled mode equations are derived which couple the electromagnetic wave mode (positive‐energy wave) and electron plasma wave mode (negative‐energy wave) propagated along a relativistic electron beam. Also, the spatial growth rate for these wave modes is obtained from these equations. Next, the energy relations for the electromagnetic and electron plasma wave modes are formulated, together with the discussion on the mechanism for energy exchange between these two modes. Finally, this paper considers the saturation in the laser output produced by trapped electrons in the electron plasma wave, and the efficiency of energy transfer from the kinetic energy of the electron beam to the laser output.
The partial realization theory of finite size two‐dimensional arrays
Authors: Matsuo Tsuyoshi , Hasegawa Yasumichi , Okada Yoshikuni 
Published: July 2007

AbstractThe authors have already proposed the realization problem for (infinite) figures (arrays) as an application of realization theory for nonlinear systems, and the array realization theorem was obtained by commutative linear representation system. A discussion was also made of the relation between the infinite array and the finite‐dimensional commutative linear representation system. This paper discusses the partial realization problem for finite arrays. The notion of natural partial realization system is introduced for a finite array and the following properties are shown.
For any arbitrary given finite array, there exists a minimum‐dimensional commutative linear representation system that partially realizes it.
The necessary and sufficient condition for the natural partial realization system to exist for a finite array is derived in terms of the condition for the rank of the bounded Hankel matrix of the finite array.
The necessary and sufficient condition for the minimum‐dimensional partial realization system to be unique except for the isomorphism is that there exists a natural partial realization system for the finite array. The proposed theory for partial realization of a finite array will be applicable to the theory for the communication of pattern information.
Two new solutions in cylindrical coordinates of electromagnetic fields of axially traveling waves and some applications
Authors: Shimizu Tatsuaki 
Published: July 2007

AbstractA new method of solving Maxwell's equations is introduced for electromagnetic waves propagating in the steady state along the z axis of a cylindrical coordinate system (r, θ, z) in free space. We solve the wave equation for the electric field E completely for two degrees of freedom and find two methods for obtaining the magnetic field by rotE. Considering completeness of the solution, the electromagnetic fields are classified and summarized in two tables. As an application example, we study complete guided modes of a clad optical fiber. It is found that the electric field preferred boundary conditions of a circular dielectric structure, complete guidance of singular (cutoff) modes with angular index m ≧ 3 and analytical expressions physicially accurate of linearly polarized remote‐cutoff HEIn modes.In one of the two new methods, the wave equation for Ez is solved first. Next, from the Er equation, Eθ is eliminated in divE = 0 and variable coefficient linear partial differential equations for unknown Er with inhomogeneous term Ez are derived. After these equations are solved for Er in both homogeneous and inhomogeneous cases, Eθ derived from divE = 0 is evaluated by using the Eθ equation. In another method, we derive simultaneous angular equations from the Er and Eθ wave equations. After solving these, we evaluate Ez derived from divE = 0.
Notes on addition over a finite field using an addition table
Authors: Sugimura Tatsuo , Kasahara Masao , Namekawa Toshihiko 
Published: July 2007

AbstractArithmetic operations on a finite field are now often used in error control or digital signal processing and there is need for a more practical method for carrying out these operations. A detailed discussion is given of the arithmetic operations, with the elements of finite field represented as powers. In other words, the addition table which can be constructed is of the order of 1/(2 · m) of the Zech logarithmic table. A detailed discussion is given of its construction algorithm, and a practical arithmetic operation algorithm using the table is presented. The size of the addition table is estimated and a storage scheme is considered for the addition table over a finite field with index 2. It is also shown that the addition table is easily set up on a computer.
Reflection of electromagnetic waves by a layer of periodically stratified dielectric medium—a remedy for TV signal interference caused by tall buildings
Authors: Yamasaki Tsuneki , Hinata Takashi , Hosono Toshio 
Published: July 2007

AbstractThis paper deals with numerical analysis of the reflection of electromagnetic waves from a conductive plate with periodic dielectric distribution. Analysis is based on the Fourier series expansion method (FEM) whereby (i) the EM fields in a periodic inhomogeneous medium are Fourier‐expanded and from this the propagation constant and modal function are found by an eigenvalue equation and (ii) the reflection coefficient is obtained from the boundary conditions between the inhomogeneous medium and free space. Previously, when the dielectric constant E(x) was Fourier‐expanded but the expansion coefficients did not converge absolutely, this method would be abandoned and another method would be sought. In this paper, even in this case, we show that the FEM is still effective. If ε(x) is expressed as ε(x) / ε0 = q(x)/r(x) and the expansion coefficient of q(x) and r(x) can be obtained analytically, it can be shown that there is no need for numerical integration. As a result, the applicability of the FEM for systematic numerical analyses of periodic and inhomogeneous media is greatly extended. Actual numerical analysis is applied to the cases of square, cubic and exponential distributions of the dielectric constant toward avoidance of reflections of the periodic, inhomogeneous layers of the medium. Also, this method may be applied to optical grating problems.
Generating functions for sampling theorems
Authors: Kida Takuro 
Published: July 2007

AbstractA general form of sampling theorem is considered in which the signal is uniquely interpolated by sample values taken at a number of uniformly spaced sample points for a band‐limited time function of the form f(t) such that ∫−∞∞|f(t)|2 dt < +∞ and whose Fourier spectrum contains components within |ω| < ω0. One of the necessary and sufficient conditions establishing such an interpolation function is derived. According to the theorem, this interpolation function can be given in terms of time functions that correspond to the coefficients obtained by Fourier series expansion with respect to a function of angular frequency and time, called the generating function. Next, for a signal of the same form considering a generalized form of the sampling theorem that deals with nonuniform sampling points, the necessary and sufficient condition for the interpolation function that ordinarily establishes this is shown. In this case it is also shown that the concept of the generating function can be extended. Further, by combining the well‐known Silverman‐Toeplitz theorem for summation of series and the sampling theorem as derived above from the outline of the generating function, several sampling theorems can be derived.
Theoretical analysis of diffraction field fluctuations due to position irregularity of diffraction gratings
Authors: Yoshida Junichi , Adachi Saburo 
Published: July 2007

AbstractThe effect on the diffraction pattern attributable to positional irregularity in a linear and equi‐spaced diffraction grating, if correlation exists between the position irregularities with respect to the reference points, is examined. The nature of these positional irregularities is twofold. In the first case, the probability distributions of the positional irregularities centered around a reference point are all identical. In the second case the effect of random variables causing the positional irregularities is accumulated and the subsequent probability distribution of the diffraction grating is strongly affected. As an example of the first case the positional irregularity of a diffraction grating resulting from thermal expansion of a waveguide is considered. One example of the second case is positional irregularity attributable to refractive index fluctuation from an acoustic wave propagating in an optical waveguide to create periodic modulation of the index. Another example of the second case is the orientation error when a grating is placed at equal intervals with respect to a previously placed grating. In the analysis it is assumed that the radiation loss at each grating is so small that the accumulation in the optical waveguide is negligible.
IL‐3 is an important differentiation factor for the development of prostaglandin E2‐producing macrophages between C57BL/6 and BALB/c mice
Authors: Kuroda Etsushi , Noguchi Junko , Doi Takahiro , Uematsu Satoshi , Akira Sizuo , Yamashita Uki 
Published: July 2007

AbstractWe have previously reported that peritoneal and splenic macrophages from Th2‐dominant BALB/c mice produced higher amounts of prostaglandin (PG) E2 than cells from C57BL/6 mice. In this study, we investigated how macrophages from BALB/c mice acquire the ability of enhanced PGE2 production, using bone marrow‐derived macrophages differentiated by M‐CSF, GM‐CSF or IL‐3. There is no strain difference in PGE2 production by GM‐CSF‐ and M‐CSF‐differentiated macrophages; however, IL‐3‐differentiated macrophages from BALB/c mice produced higher amounts of PGE2 and lower amounts of type I cytokines than cells from C57BL/6 mice. IL‐3‐differentiated macrophages from BALB/c mice expressed larger amounts of mRNA of membrane‐bound (microsomal) PGE synthase‐1 (mPGES‐1). The amounts of PGE2 produced by macrophages were significantly reduced in mPGES‐1‐deficient mice, and these mice displayed enhanced Th1 responses after Propionibacterium acnes treatment compared with wild‐type mice. Microarray analysis revealed 63 genes that are differentially expressed more than fivefold in macrophages between C57BL/6 and BALB/c mice. These results indicate that mPGES‐1‐mediated PGE2 produced by macrophages regulates immune responses, and IL‐3 is an important factor for the differentiation of macrophages that produce higher amounts of PGE2 through mPGES‐1 activity in BALB/c mice.
Antigen co‐encapsulated with adjuvants efficiently drive protective T cell immunity
Authors: Heit Antje , Schmitz Frank , Haas Tobias , Busch Dirk H. , Wagner Hermann 
Published: July 2007

AbstractCompared to "live" vaccines, the immunogenicity of "subunit" vaccines based on recombinant antigen (Ag) is poor, presumably because exogenous Ag fails to effectively access the endosomal Ag‐processing pathways of Ag‐presenting cells (APC). To overcome this limitation, we exploited biodegradable poly(lactic‐co‐glycolic) microspheres (MP) co‐entrapping Ag and Toll‐like receptor (TLR) 9 or 7 ligands as an endosomal delivery device. In vitro, microspheres were rapidly phagocytosed by APC and translocated into phago‐endosomal compartments, followed by degradation of the Ag and concurrent activation of endosomal TLR. As a consequence, full maturation of and cytokine secretion by APC as well as Ag‐cross‐presentation ensued. In vivo, "loaded" microspheres triggered clonal expansion of primary and secondary Ag‐specific CD4 and CD8 T cells. The efficacy of CD8 T cell cross‐priming was comparable to that of live vectors. The potency of T cell vaccination was demonstrated by protective and therapeutic interventions using infection‐ and tumor‐model systems. These preclinical "subunit" vaccination data thus recommend MP as a generally applicable and powerful endosomal delivery device of exogenous Ag plus TLR‐based adjuvants to vaccinate for protective and therapeutic CD4 and CD8 T cell immunity.
General and Efficient One‐Pot Synthesis of Tertiary Phosphane–Borane Complexes Containing Different Alkyl Groups and In Situ Facile Recycling of the Phosphorus Donor Reagent
Authors: Baccolini Graziano , Boga Carla , Mazzacurati Marzia 
Published: July 2007

AbstractTertiary symmetric and asymmetric phosphane–borane complexes containing different alkyl groups, including bulky groups, can be obtained by the addition of different Grignard reagents to benzothiadiphosphole 1 followed by direct complexation with BH3·THF. Treatment of the resulting mixture with PCl3 led to the reformation of the starting reagent 1, which was recovered from the reaction mixture by simple crystallization. The phosphane complexes were purified by chromatography of the mother liquor. This procedure is highly atom‐economic and environmentally friendly. All the reaction intermediates were identified.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Selena‐Aza‐Payne‐Type Rearrangement of Aziridinylmethyl Tosylates Mediated by Tetraselenotungstate
Authors: Sureshkumar Devarajulu , Koutha Srinivasamurthy , Chandrasekaran Srinivasan 
Published: July 2007

AbstractTetraselenotungstate 1 reacts with simple (N‐tosylaziridinyl)methyl tosylate derivatives to give allylamine derivatives as the only products by an unprecedented selena‐aza‐Payne‐type rearrangement. When the methodology is extended to disubstituted (N‐tosylaziridinyl)methyl tosylates, regio‐ and stereospecific ring‐opening of the aziridines occurs to afford allylamine derivatives as the major products and cyclic five‐membered diselenides as the minor products in good yields under mild reaction conditions without using any Lewis acid or base. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Twenty first century work issues: A look back
Authors: Hershel‐Chow Gloria 
Published: July 2007

AbstractEmployment Relations Today is pleased to present the keynote address, presented in Chicago at the 2099 Conference of the International Workplace Society, by Gloria Hershel‐Chow, president of The Globe at Work. The Globe at Work is the world's foremost membership association for human resources executives. I t has 843 organizational members and 2,412 individual corporate representatives.