bluuebunny/crossref_metadata_2025_split huggingface dataset:
Realization of two‐dimensional digital filters with powers‐of‐two coefficients
Authors: Todaka Chiaki , Kambayashi Noriyoshi 
Published: July 2007

AbstractThis paper aims at the simplification of operation and the reduction of hardware complexity and presents the construction of the two‐dimensional digital filter using powers‐of‐two coefficients. The proposed two‐dimensional digital filter is composed of a cascade connection of one‐dimensional digital filters with different frequency axis. The digital filter is structured as a cascade connection of the stopband‐forming filter and the passband‐compensating filter.The stopband‐forming filter is composed of the cascade connection of recursive running sum (RRS), and the passband‐compensating filter is constructed as a linear‐phase FIR or IIR type. The proposed method is especially effective for constructing a narrowband LPF. The zero coefficient sensitivity is realized by eliminating the multiplier. Another point is that the elliptic or polygonal two‐ dimensional filter can be approximated, which has been impossible by McClellan transform.The proposed method can realize more general two‐dimensional digital filters with a smaller hardware complexity, thereby eliminating the multiplier. Finally, it is verified by design examples that the hardware complexity is reduced in the proposed two‐dimensional digital filter, compared to the traditional method.
Sampling and reconstruction of smooth three‐dimensional convex shapes
Authors: Ohtake Kohhei , Kaneko Michio 
Published: July 2007

AbstractIn digitally transmitting or recording three‐dimensional shapes, to decrease the amount of transmitted information and memory volume, investigations of efficient shape description and sampling‐reconstruction methods are considered important.This paper investigates these problems with shapes restricted to smooth, bounded three‐dimensional convex shapes.First, as the representation methods of these shapes, the tangential plane polar coordinate representation is shown and it is explained that this is an efficient representation consistent with the curvature.Next, from this representation function, spectra and band of the shape are introduced by using surface harmonics as basic functions and their fundamental properties are described. Based on this, a sampling theorem of three‐dimensional shapes is shown which states that for band‐limited shapes, the shape can be reconstructed from a fixed number of sample values. Moreover, for band‐unlimited shapes, distortion occurs in shapes reconstructed from a finite number of sample values.A sampling method is shown which minimizes this shape distortion power and clarifies that the method is a variable density sampling which arranges sampling points with density proportional to the curvature of shape.Finally, simulation results of shape‐sampling and reconstruction system performed on ellipsoid to confirm the authors' theory are described.
Development of support facilities for arithmetical word problem exercises in intelligent tutoring system
Authors: Hirashima Tsukasa , Kohno Takahiro , Kashihara Akihiro , Toyoda Jun'Ichi 
Published: July 2007

AbstractIn the problem solving of the arithmetical word problems, the process until the solution method is identified as the most important.It is necessary to design and develop the basic functions for exercise problem support in an intelligent tutoring system (ITS), such as problem solving, problem generation, and problem explanation, aiming at the support for the identification of the solution method. In this study, those three basic functions are realized based on the problem‐solving method MIPS (model of indexing in problem solving).This paper describes the problem‐solving module, the problem‐generation module and the problem‐explanation module. The problem‐solving module not only solves the arithmetical word problem but also generates the cognitive description of the identification process for the solution method. The problem‐generation module can generate the problem which specifies what students should do in the identification process. The problem explanation module can indicate the equivalence and difference between any two problems concerning the identification process.
Minimization of coefficient sensitivity for block‐state realizations of state‐space digital filters
Authors: Tsunekawa Yoshitaka , Shida Junichi , Kawamata Masayuki , Higuchi Tatsuo 
Published: July 2007

AbstractThis paper considers the case where the block‐state realization is applied to state‐space digital filters and discusses the synthesis method for the minimum coefficient sensitivity realization.First, the method to evaluate the coefficient sensitivity in the block‐state realization, which has already been reported by the authors, is shown. Then the synthesis method for the minimum coefficient sensitivity realization is presented based on the evaluation method for the cases with and without the scaling constraint. It is shown as a result that the minimum coefficient sensitivity realization can be derived as a balanced structure also in the block‐state realization, as in the usual state‐space realization.Finally, calculation examples are shown for those synthesis methods and the validity of the proposed synthesis method is demonstrated by the satisfactory results. It is shown also that the minimum coefficient sensitivity structure for the block‐state realization derived by the proposed synthesis method is equivalent to the filter structure in the block‐state realization, which is derived from the minimum coefficient sensitivity structure in the usual state‐space realization.
A new method of pitch modification by complex cepstrum analysis‐synthesis
Authors: Seiyama Nobumasa , Takagi Tohru , Umeda Tetsuo , Miyasaka Eiichi 
Published: July 2007

AbstractThis paper proposes a new method of high‐quality pitch modification by complex cepstrum analysis‐synthesis algorithm (hereafter referred to as the CCAS algorithm).The algorithm of the new conversion method presented here is as follows: the complex cepstra obtained within each pitch‐synchronized frame are divided into pitch components and other spectral components by using comb filters.The pitch pulses obtained by inverse transformation of the pitch components are equalized adaptively to zerophase, while the spectral components also are transformed inversely into unit responses in time‐domain. This equalization makes the pitch components more impulsive, resulting in clear separation of the voice source from the vocal tract characteristics. Speech synthesis is performed by convoluting the phase‐adjusted pitch pulses with the nit responses.The results of listening tests showed that the pitchmodified speech by the CCAS method subjectively retains as high quality as the original speech.
Relations between the constants of electrostrictive materials and some examples of their application to piezoelectric ceramics
Authors: Cho Yasuo , Matsuno Fumihiko 
Published: July 2007

AbstractThis paper describes the piezoelectric phenomenon caused by the electrostrictive effect from the standpoint of material constants. First, the e, d, g, and h types of basic equations for the piezoelectric phenomenon including the nonlinear terms will be discussed to clarify the transformation formula between nonlinear constants.The forementioned formula is essential in the analysis of the material constants. Then the relationships among the constants before and after the polarization operation including the nonlinear constants will be clarified.It will be shown that if the deformation by polarization is small, the material with C∞ symmetry which is obtained by the polarizing isotropic body has a fewer number of independent constants than a 6‐mm crystal.Finally, the foregoing results will be applied to PZT ceramics and it will be shown that the theory of electrostriction is useful in evaluating piezoelectric ceramics.
Conversion of sinusoidal frequencies to gray code
Authors: Noro Yuichi , Inomoto Kenji , Kuno Kazuhiro 
Published: July 2007

AbstractA method of straightforward conversion of sinusoidal frequency to Gray code expression is described. The unknown frequency is estimated using only the sign of the inverse cosine function. The frequency conversion error is shown by computer experiment. For a more accurate result, the majority decision principle and threshold logic, that is, a maximum likelihood estimator, are applied. Hardware implementation is so easy that the whole system can be implemented on an LSI chip.
SAW resonators using epitaxially grown Al electrodes
Authors: Ieki Hideharu , Sakurai Atsushi 
Published: July 2007

AbstractStress migration (SM) has become a serious issue with the development of surface acoustic wave (SAW) devices for high‐frequency application. For the first time, this paper discusses epitaxially grown Al electrode films as a countermeasure to SM. It also discusses a method of epitaxial growth of Al electrode films for an SAW resonator deposited onto quartz substrates. It is found that an epitaxially grown film has been fabricated under relatively moderate deposition conditions in vacuum evaporation. The orientation relation for this epitaxial growth is (311) «233»Al//(032)«100»SiO2. The SM lifetime for the SAW resonator thus obtained is found to be more than 2000 times longer and the allowable power value is improved by one order of magnitude more than that usually obtained for polycrystalline Al films with Cu. A discussion of the epitaxial growth mode and lifetime of electromigration also is presented.
Mobile communication systems and surface acoustic wave devices
Authors: Yamanouchi Kazuhiko 
Published: July 2007

AbstractWith the advent of a highly intelligent society, the role of mobile communication represented by the key words “anytime, anywhere, and with anybody” has become increasingly important. This paper describes mainly the mobile stations of the digital communication system in which the frequency‐use efficiency is improved significantly, as well as of analog mobile communication system. Also described are the surface acoustic wave devices, especially the low insertion loss filters, which are expected to be the key devices of mobile communication for small and lightweight equipment.
A low‐loss bandpass filter using SAW resonators
Authors: Satoh Yoshio , Ikata Osamu , Miyashita Tsutom , Matsuda Takashi , Nishihara Tokihiro 
Published: July 2007

AbstractA filter structure having a ladder network of one‐port surface acoustic waves (SAW) resonators was studied, as a development of low‐loss, high‐frequency bandpass filters. A simulation tool was developed first and used for the design of the filters. It was found that the loss and the stopband attenuation can be controlled by the ratio of the capacitance for the parallel arm resonator Cop and that for the serial arm resonator Cos, i.e., CopCos. It was revealed also that the input and output impedances can be matched to 50 Ω by maintaining a certain relationship between Cop and Cos. Based on these findings, 900—MHz and 1.5—GHz RF filters were designed and prototyped for portable telephone applications. The 900—MHz filter has the insertion loss of 1.5 to 3 dB, the stopband attenuation of 20 to 30 dB, and the input output VSWR of less than 2, and requires no impedance matching circuit. Similar characteristics were achieved by the 1.5—GHz filter. The insertion loss turned out to be approximately half of what was achieved by the conventional transversal filters.
Solution of nonlinear simultaneous equation possessing transcendental functions by polynomial approximation method
Authors: Fujisaka Hisato , Sato Chikara 
Published: July 2007

AbstractThis paper presents a method of solving the simultaneous nonlinear equations containing transcendental functions in a specified domain. The features of the method are that the analysis can be executed in the complex domain by using the algebraic analysis and in the infinite range for the variable not contained in the transcendental function. The method is composed of the following procedures.The specified domain of analysis is divided into subdomains, and the transcendental function is approximated by a polynomial in each subdomain. Using the computation algorithm for the Groebner basis, the single‐variable algebraic equation is derived and the number and the value of the approximate solution are determined. The computer algebra is applied to the computation process, and the efficiency of the calculation of the approximate solution is improved by deriving several polynomials called prime basis, together with the single‐variable equation.To calculate the solution for the original equation based on the approximate solution, the techniques for numerical analysis such as Newton's method are employed. The reliability of the solution method is improved by the bifurcation analysis between the real and the complex‐valued solutions whenever necessary.
New cuts for width‐extensional mode quartz crystal resonators
Authors: Kawashima Hirofumi 
Published: July 2007

AbstractThis paper describes various characteristics for a width‐extensional mode quartz crystal resonator. A new cut is proposed for a width‐extensional mode quartz crystal resonator, which is designated the “KT‐cut,” and clarifies its frequency characteristics, frequency temperature behavior, and electrical characteristics.First, a frequency equation is derived under the conditions that widthx0is much larger than thicknessz0but much smaller than lengthy0by solving partial differential equations for a new‐shape GT‐cut quartz crystal resonator already obtained with variational principle. This is because the modified shape for the present resonator is referred to as that of the new‐shape GT resonator.Next, from the obtained equation, relationships of resonant frequency versus widthx0and the first‐ and second‐order temperature coefficients α, β versus a cut angle θ are analyzed theoretically. As a result, a cut angle θ which gives α = 0 approximately is θ = 24.5° at the reference temperature of 20°C and β has a value of β = −0.60 × 10−8/°C2. This value is then compared with the measured values of β = −1.25 × 10−8/°C2and the absolute value in the experiments is found to be about twice the calculated value. In addition, α and β are very dependent on a thickness‐to‐width ratioRzx(thicknessz0/widthx0), and have a parabolic curve versus the ratioRzx. Thus, α and β are also found to vary withRzx.Finally, series resistanceR1, and a quality factorQare primarily examined in the frequency range of approximately 8.7 to 32 MHz. Consequently, e.g., whenf= 16.3 MHz, a width‐extensional mode quartz crystal resonator is found to be obtained successfully with satisfactory values ofR1= 89.7 Ω andQ= 180, 000.
TLR9 stimulation drives naïve B cells to proliferate and to attain enhanced antigen presenting function
Authors: Jiang Wei , Lederman Michael M. , Harding Clifford V. , Rodriguez Benigno , Mohner Richard J. , Sieg Scott F. 
Published: July 2007

AbstractMechanisms that regulate naïve B cell proliferation and function are incompletely defined. In this study, we test the hypothesis that naïve B cell expansion, survival and ability to present antigen to T lymphocytes can be directly modulated by Toll‐like receptor (TLR) agonists. In the absence of B cell receptor stimulation, CpG oligonucleotide, a TLR9 agonist, was particularly efficient in inducing naïve B cell proliferation and survival. Although the expanded naïve B cells did not mature into CD27+ or IgG+ memory B cells, these cells did differentiate into IgM‐secreting cells with increased surface expression of HLA‐DR, CD40 and CD80. This was associated with an increased potential for these B cells to activate allogeneic T cells. We propose that the activation and expansion of naïve B cells induced by TLR9 agonists could enhance the potential of these cells to interact with cognate antigens and facilitate cell‐mediated immune responses.
Enantiospecific Synthesis and Chiroptical Properties of Bicyclic Enones
Authors: Orentas Edvinas , Bagdžiūnas Gintautas , Berg Ulf , Žilinskas Albinas , Butkus Eugenijus 
Published: July 2007

AbstractThe enantiospecific synthesis of several bicyclic enones starting from enantiomerically pure (+)‐(1S,5S)‐bicyclo[3.3.1]nonane‐2,6‐dione (1) was accomplished. The target enones 7–9 were obtained in high yield and purity by using a catalytic amount of benzeneselenic anhydride. (+)‐(1S,5R)‐bicyclo[3.3.1]nonane‐2,3,6‐trione was obtained from diketone 1 by α‐hydroxylation involving the use of iodine under basic conditions. The reaction included a ring closure/reopening sequence via oxatricyclo[4.3.1.03,8]decane‐10‐one. It was shown that the latter triketone exists in enone/enol form. Chiroptical properties of the enantiomerically pure compounds were studied, and the sign of the Cotton effect was related to the absolute configuration of the enones. The positive Cotton effect in the bisignate CD curve is accounted for by the nonplanarity of the chromophore in enones (1S,5R)‐4 and (1S,5S)‐8. The circular dichroism spectra provided evidence for interchromophoric interaction in dichromophoric bis(enone) 9. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Isoxazoles and Isoxazolines by 1,3‐Dipolar Cycloaddition: Base‐Catalysed Condensation of Primary Nitro Compounds with Dipolarophiles
Authors: Machetti Fabrizio , Cecchi Luca , Trogu Elena , De Sarlo Francesco 
Published: July 2007

Abstract1,4‐Diazabicyclo[2.2.2]octane (DABCO) or other suitable N‐bases cause primary activated nitro compounds to condense with alkenes to yield isoxazolines or with alkynes to give isoxazoles. As the molar ratio of the base with respect to the dipolarophile decreased, the reaction became slower, but the nitro compound became more resistant to hydrolytic cleavage. The best results were achieved with a molar ratio of base in the range of 0.05–0.1. The reactions were carried out in chloroform at 60 °C; for ethyl nitroacetate and phenylnitromethane, ethanol at 80 °C can be employed with better results and shorter reaction times. A catalytic cycle is proposed: in chloroform the hydrogen‐bonded ion pair formed between the nitronate and the protonated base undergoes reversible cycloaddition with the dipolarophile and then the hydrogen‐bonded intermediate adduct releases water by reaction with a second nitro molecule to give the product and the hydrogen‐bonded nitronate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Convenient and General Method for the Synthesis of Indole‐2,3‐dicarboxylates and 2‐Arylindole‐3‐carboxylates
Authors: Sayyed Iliyas Ali , Alex Karolin , Tillack Annegret , Schwarz Nicolle , Michalik Dirk , Beller Matthias 
Published: July 2007

AbstractA transition‐metal‐free, simple and efficient one‐pot method for the synthesis of indole‐2,3‐dicarboxylates and 2‐arylindole‐3‐carboxylates is described. The corresponding products are obtained by a domino hydroamination/Fischerindole cyclization in good‐to‐excellent yields from easily available 1‐alkyl‐1‐phenylhydrazines and acetylene carboxylates.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
L‐Cysteine Voltammetry at a Carbon Paste Electrode Bulk‐Modified with Ferrocenedicarboxylic Acid
Authors: Raoof Jahan‐Bakhsh , Ojani Reza , Beitollahi Hadi 
Published: July 2007

AbstractThe electrochemical behavior of L‐cysteine studied at the surface of ferrocenedicarboxylic acid modified carbon paste electrode (FDCMCPE) in aqueous media using cyclic voltammetry, differential pulse voltammetry and double potential step chronoamperometry. It has been found that under optimum condition (pH 8.00) in cyclic voltammetry, the oxidation of L‐cysteine occurs at a potential about 200 mV less positive than that of an unmodified carbon paste electrode. The kinetic parameters such as electron transfer coefficient, α, and catalytic reaction rate constant, kh were also determined using electrochemical approaches. The electrocatalytic oxidation peak current of L‐cysteine showed a linear dependent on the L‐cysteine concentration and linear analytical curves were obtained in the ranges of 3.0×10−5 M–2.2×10−3 M and 1.5×10−5 M–3.2×10−3 M of L‐cysteine concentration with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods respectively. The detection limits (3σ) were determined as 2.6×10−5 M and 1.4×10−6 M by CV and DPV methods.
Modelling of solute transport in a mild heterogeneous porous medium using stochastic finite element method: Effects of random source conditions
Authors: Chaudhuri A. , Sekhar M. 
Published: July 2007

AbstractRandomness in the source condition other than the heterogeneity in the system parameters can also be a major source of uncertainty in the concentration field. Hence, a more general form of the problem formulation is necessary to consider randomness in both source condition and system parameters. When the source varies with time, the unsteady problem, can be solved using the unit response function. In the case of random system parameters, the response function becomes a random function and depends on the randomness in the system parameters. In the present study, the source is modelled as a random discrete process with either a fixed interval or a random interval (the Poisson process). In this study, an attempt is made to assess the relative effects of various types of source uncertainties on the probabilistic behaviour of the concentration in a porous medium while the system parameters are also modelled as random fields. Analytical expressions of mean and covariance of concentration due to random discrete source are derived in terms of mean and covariance of unit response function. The probabilistic behaviour of the random response function is obtained by using a perturbation‐based stochastic finite element method (SFEM), which performs well for mild heterogeneity. The proposed method is applied for analysing both the 1‐D as well as the 3‐D solute transport problems. The results obtained with SFEM are compared with the Monte Carlo simulation for 1‐D problems. Copyright © 2007 John Wiley & Sons, Ltd.
Development of new methods for asymmetric synthesis based on sulfoximines
Authors: Gais Hans‐Joachim 
Published: July 2007

AbstractSulfoximine‐substituted bis(allyl)titanium complexes, which are configurationally labile at the Cα‐atoms, have emerged as valuable reagents in asymmetric synthesis. Their highly selective reactions with aldehydes and N‐sulfonyl imino esters allow the attainment of enantio‐ and diastereomerically pure sulfoximine‐substituted homoallylic alcohols and homoallylic amines, respectively, which are valuable starting materials for the asymmetric synthesis of homopropargylic alcohols, 2,3‐dihydrofurans, medium‐sized carbocycles and lactones, unsaturated mono‐ and bicyclic prolines, β‐amino acids, and vinyl oxiranes, respectively. The high synthetic versatility of the sulfoximine group stems from its ability to function as a chiral carbanion‐stabilizing nucleofuge. © 2007 Wiley Periodicals, Inc. 18:472–481, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20331
Reactions of cysteine sulfenyl thiocyanate with thiols to give unsymmetrical disulfides
Authors: Alguindigue Nimmo Susan L. , Lemma Kelemu , Ashby Michael T. 
Published: July 2007

AbstractCysteine sulfenyl thiocyanate (CSSCN) reacts with thiols at pH 0 to cleanly yield disulfides. 2‐Mercaptoethanol (2‐MESH), 3‐mercaptopropionic acid (3‐MPASH), penicillamine (PENSH), and glutathione (GSH) react with CSSCN to give the corresponding mixed disulfides: 2‐MESSC, 3‐MPASSC, PENSSC, and GSSC. These compounds are stable at pH 0 and have been characterized by 1H and 13C NMR spectroscopy. © 2007 Wiley Periodicals, Inc. 18:467–471, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20340