bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Trifluoromethylations and Related Reactions in Organic Chemistry
Authors: MCCLINTON M. A. , MCCLINTON D. A. 
Published: July 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Significance of the Bond Lengths and Bond Orders of Conjugated Unsaturated Organic Molecules. The Role of Hetero‐Aromaticity in the Tertiary Structures of DNA
Authors: BOX V. G. S. 
Published: July 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Hard Amorphous (Diamond‐Like) Carbons
Authors: ROBERTSON J. 
Published: July 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Heavy‐Metal Oxide Glasses
Authors: DUMBAUGH W. H. , LAPP J. C. 
Published: July 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Analysis of transmission lines with distributed sources
Authors: Ichikawa Satoshi 
Published: July 2007

AbstractThe fundamental equation for the voltage and current in the transmission‐line with distributed sources can be converted into the state equation in the operator domain by using the Laplace transform. The general. solution of this equation contains the initial condition, which can be specified arbitrarily. This paper presents a method in which the arbitrary condition is specified by numerically solving the system of equations derived from the boundary condition of the transmission line. By applying the inverse transform to the solution for the voltage and current of the transmission line obtained in the operator domain, the steady‐state and the transient solutions in the time‐domain can be determined. As the inverse transform, ac analysis is applied for steady state, and the numerical Laplace transform is used for transient analysis. As an application example, the steady‐state and the transient analysis are performed for the transmission line being affected by the external electromagnetic field. The effectiveness of the proposed method is verified by comparing the result with the result of other methods.
Adaptive delta modulation using slope overload detection method
Authors: Ishii Ikuo , Itoh Masayuki 
Published: July 2007

AbstractA simple and efficient algorithm is presented for the improvement of adaptive delta modulation (ADM) speech encoder. This paper attempts to realize an ADM encoding scheme having both a simple encoding/decoding procedure due to conventional backward estimation ADM and excellent encoding performance due to the delayed encoding ADM.The characteristics of delayed encoding ADM with Jayant type step‐size adaptation method and the redundancy in ADM code generation procedure are analyzed, and then a method of reducing the redundancy is studied. A highly efficient encoding method is realized by improving the deciding method of ADM codes and simplifying the computation procedure. Since the proposed method employs slope overload detection with delayed decision, it is called Slope Overload Detection ADM scheme. This scheme can give S/N gain of about 5.5 dB at a 16 KHz encoding frequency using the Jayant ADM with double integrator. Using an extremely simple procedure, it can also achieve encoding performance similar to that of the delayed decision ADM.
Concealment methods based on kalman filter
Authors: Suda Hirohito , Hosokawa Takahiro , Imai Hideki 
Published: July 2007

AbstractWhen an analog waveform is digitized and transmitted over a digital channel, a combination of an error‐correction technique and a concealment method is often employed to improve the quality of the communication system. New concealment methods based on the Kalman filter are Kalman filtering concealment (KFC), scalar‐approximation concealment (SAC) and symbol states estimating concealment (SSEC). It is shown by simulation that these three methods provide better performance than conventional methods. The use of redundancy in the error‐correcting codes and the statistics of the analog information source is the core concept of the new concealment methods. In particular, the SSEC method is shown to be superior to other methods in its effective realization of this concept.
A fast algorithm for the cosine transform based on successive order reduction of the chebyshev polynomial
Authors: Morikawa Yoshitaka , Hamada Hiroshi , Yamane Nobumoto 
Published: July 2007

AbstractThe discrete cosine transform (DCT) is one of the discrete orthogonal transformations, for which fast computation algorithms are known. It has the property that the transformed sequence has most of the energy in the lower‐order components, and is utilized widely in feature extraction and high‐efficiency coding. The following methods have been known as the fast‐cosine transform (FCT): (1) Computation is performed through the fast‐Fourier transform (FFT) with real sequence; (2) Computation is made by decomposing the matrix representing DCT into sparse factors. In those methods, approximately N log2N real multiplications and (3/2)N log2N real additions are required for computation of DCT for N = 2v points. The FCT proposed in this paper differs from those methods in the following points. The DCT is represented by a finite series of Chebyshev polynomials. The order of the series is successively halved utilizing the successive factorization of Chebyshev polynomial, finally arriving at DCT values. By this method, (1/2) N log2N real multiplications and (3/2) N log2N real additions suffice to calculate the DCT for N points: the number of multiplications is halved, compared with the previous methods. The method is similar, in its structure, to FFT with radix 2, which leads to the feature that the programming is simple.
Finite element approach to unbounded poisson and helmholtz problems using hybrid‐type infinite element
Authors: Yamabuchi Tatsuo , Kagawa Yukio 
Published: July 2007

AbstractElectric or sound field problems associated with an open boundary governed by a Poisson or Helmholtz equation, are analyzed via the finite element method in conjunction with a hybrid‐type infinite element. The original size and bandwidth of the system matrix of the finite region do not increase after connection of the infinite element matrices for expressing the outer infinite region. In this paper, errors associated with numerical calculations are examined for 3‐D fields in consideration of the infinite region. First, an infinite element matrix for 3‐D infinite acoustic field is derived. The formulations are easily applicable to the 3‐D electric field problems. Next, the numerical calculations are demonstrated for the acoustic field caused by a point driving source and the results are compared with the analytical solutions. Another numerical example is the calculation of electric field caused by a pair of electric charges. Reasonable accuracy is confirmed in the finite region, but the accuracy in the infinite region is not always satisfactory. The decay function used for the infinite element plays an important role in accuracy. The decay parameter can be determined by the aid of the minimum condition of the functional and it is found that the use of this condition promises reasonable results.
Numerical algorithm for Taylor series expansion
Authors: Hosono Toshio 
Published: July 2007

AbstractA new numerical algorithm for computing the coefficients of Taylor series expansion has been developed. As the result of error analysis, thirteen significant digits can be obtained by double precision (16 digits) computation, which was also verified by numerical experiment. Applications to Computation of residue, z‐transform, Laplace tranform, and Taylor expansion of inverse functions are described. Also, errors in the volume, Mathematical Formulas by Iwanami Co., are found through computations.
Effect of a limit cycle on an output signal
Authors: Ishii Rokuya , Kato Masafumi 
Published: July 2007

AbstractThe effect of limit cycles on an output signal is studied in an all‐pole secondorder digital filter when an input signal is sinusoidal. First, limit cycles and an output signal are evaluated theoretically in the regions where the operation in the digital filter is linear. Next, the distortion rate in a digital signal is defined. Using this value, we estimate the bit number of the amplitude of an input signal required to distinguish the output signal from the limit cycle. Moreover, we also estimate the necessary bit number of the amplitude of an input signal when the random rounding is employed as an elimination method of limit cycles.
A design of optical wavelength‐division‐multiplexing transmission systems
Authors: Sano Koichi , Watanabe Ryuichi 
Published: July 2007

AbstractIn a wavelength‐division‐multiplexing transmission system optical signals with different wavelengths can be transmitted in multiplex via one optical fiber. Since this system not only increases the transmission capacity but also permits two‐way transmission and simultaneous transmission of heterogeneous signals, it is being studied as an effective technique for optical transmission.This paper describes a basic design method for an optical wavelength‐division‐multiplexing transmission system. Types and wavelengths of optical sources and the wavelength dependence characteristics of multi/demultiplexer are designed so that the two criteria of optical receiving power and optical S/X satisfy required system configurations. This paper also presents experimental results for a fabricated multi/demultiplexer designed for a 4‐wavelength multiplexed optical subscriber loop system. The experimental results of this multi/demultiplexer are in good agreement with the designed performance and the proposed design method is shown to be effective.
DSP‐type first‐order digital phase‐locked loop using linear phase detector
Authors: Hagiwara Masafumi , Nakagawa Masao 
Published: July 2007

AbstractWith the development of modern digital technology, phase‐locked loops (PLL) are also becoming digitalized. The digital signal processing (DSP)‐type digital PLL (DPLL) realized by microprocessors and software deserves particular interest. This is because it can be used in time‐sharing operation and its characteristics can easily be controlled. Therefore, it will probably be used widely in digital communication for synchronization and signal conversion circuits. However, up to now, the DSP‐type DPLL has been derived from an analog PLL by directly realizing its operation with DSP methods. Consequently, the generation of distortion components due to the nonlinear characteristic of the phase detection can not be avoided. Moreover, the high‐frequency components arising from the multiplication in the phase detector have a harmful influence on DPLL operation. This paper proposes a new DSP‐type DPLL which eliminates the forementioned disadvantages. This DPLL applies subtraction instead of multiplication in the phase detector to eliminate high‐frequency components. In this way the phase detection linear and does not produce distortion components. Furthermore, it has an AM suppression effect and therefore automatic gain control (AGC) circuit is not needed.
Methods for evaluating error correcting codes based on a compound channel model
Authors: Suematsu Toshinari , Imai Hideki 
Published: July 2007

AbstractSince error correcting and detecting codes are used in many fields, the assessment of the code performance in actual communication environments is an important subject. A communication channel is expressed by a statistical model and the assessment is usually done by simulation and/or analysis method. However, conventional assessment methods are insufficient from the viewpoint of ease of handling, precision, etc. In this paper we present new methods for evaluating error‐correcting and error‐detecting codes. These evaluations make use of a new compound channel model which represents actual channels better than the channel models proposed previously. An exact analysis is used for computing the performances of codes. For these reasons, we can obtain reliable results. The time required for the evaluation is relatively small. Furthermore, their adaptability to various channels and codes is high and they are easy to use. Methods of evaluating the double encoding scheme, a well‐known scheme in CIRC, is also presented. Finally, some examples of evaluating codes by these methods are presented and their effectiveness is shown.
Utilization of a lambda (Λ)‐shaped transistor for a hardware neuron model
Authors: Sekine Yoshifumi , Suyama Masatoshi , Nakamura Masahiko , Ochiai Toshiyuki 
Published: July 2007

AbstractInformation processing in a biological system is more redundant than in a computer system, realizing real‐time processing, eventhough the individual processing speed is low. This paper discusses a neuron electronic model; it is considered the core of biological information processing that has application to engineering problems. The circuit is based on the element which uses a Λ‐shaped transistor, a three‐terminal voltage‐controlled negative‐resistance device, to realize both negative resistance and inductance. It is shown that a hardware neuron model can be constructed by a simple circuit. The existence of a threshold and the generation of action potential are discussed, together with other characteristics of the model. It is then shown that, by improving the Λ‐shaped transistor, a hardware neuron model can be constructed with the self‐organizing function with adjustable threshold. The model is compared with BVP and HH models. A hardware neuron model with K‐conductance characteristics of H‐H model is constructed, followed by the discussion of characteristics such as those for constant‐current stimulation. Through this analysis, it is demonstrated that the proposed model can well simulate the biological neuron, and has the potential to be applied to engineering problems.
Vibration analysis of flexural–torsional mode tuning fork–type resonators
Authors: Kawashima Hirofumi 
Published: July 2007

AbstractIt is well known that a flexuraltorsional quartz crystal resonator which couples a torsional mode vibration to a flexural mode vibration, has a cubic curve in frequency temperature characteristics as well as an AT cut quartz crystal resonator. This paper describes the frequency‐temperature characteristics of a tuning fork‐type quartz crystal resonator which couples the torsional mode vibration to the flexural mode vibration and the estimated results of the various constants for the resonator manufactured for trial experiments. First, a secular equation coupled the torsional mode vibration to the flexural mode vibration is calculated. From the secular equation, frequency‐temperature characteristics for the flexural‐torsional mode tuning fork‐type resonator have been analyzed theoretically, specifically concerning a relationship of the resonant frequency, the frequency‐temperature coefficients vs. thickness, a normalized frequency and a cut angle. Next, by manufacturing tuning fork‐type flexural‐torsional quartz crystal resonators, the calculated values are compared with the experimental values, at the same time, the various constants of the resonators manufactured for trial experiments are estimated. As a result, it is confirmed that tuning fork‐type flexural‐torsional quartz crystal resonators with excellent frequency‐temperature characteristics, low‐crystal impedance, and a high quality factor are realized.
Masking by tone bursts of changing frequency
Authors: Kitamori Susumu 
Published: July 2007

AbstractMost of the common sounds in our daily life change their frequencies transiently, and it is important in engineering applications such as voice recognition and instrument tone discrimination to find a correspondence between the physical properties of these sounds of changing frequency and human perception. This paper reports on the experimental study of masking by tone bursts of changing frequency as an effort toward clarifying such dynamic auditory perception. First, using artificial formant stimuli the masking patterns for continuous tones were measured with the formant frequency changed discontinuously. The results showed masking overshoot at the formant transition and forward and backward masking phenomena, which suggests a characteristic extraction of the voice formant transition in the auditory system. Next, using various combinations of artificial formant and “bridge” tones as the masker, the masking patterns for continuous tones mixed with the masker at various phases were measured. As a result it became clear that the resultant pattern is not a simple addition of individual maskings by the component tones and shows relatively sharp bandpass filter characteristics in the critical band of the auditory system. This suggests the existence of a special processing mechanism for compound consonants in the auditory system.
Range‐extended tangent‐type FM demodulator using digital signal processing
Authors: Hagiwara Masafumi , Nakagawa Masao 
Published: July 2007

AbstractFM demodulators using Digital Signal Processing (DSP) are smaller and more reliable than conventional analog FM demodulators. The authors have already proposed an improved tangent‐type FM demodulator (I‐TAN) capable of extending the demodulation range without introducing distortion.This paper proposes a new range‐extended TAN‐type FM demodulator (RE‐TAN) capable of extending the demodulation range for wideband FM signal without increasing the sampling rate.The range can be extended incrementally by increasing the number of stages of the range extender proposed in this paper.
Constitution of wide area telephone network using optical fiber communication
Authors: Akiyama Minoru , Tanaka Yoshiaki , Suzuki Norihiro 
Published: July 2007

AbstractWith recent, remarkable development of optical fiber technology optical fibers are replacing conventional coaxial cables and microwave systems in the toll telephone network. This paper optimizes a telecommunication network configuration which uses large‐capacity transmission systems such as optical fibers. In a hypothetical Japanese toll telephone network, the required numbers of circuits and systems are calculated and compared for five types of network models (i.e., mesh, lattice, ring, ring‐mesh composite and star‐mesh composite types). As a result of these calculations, the 400–Mb/s system and 1.6–Gb/s system are shown to be applicable to most of the toll transmission sections. The required amounts of circuits increase in the order of lattice type, ring‐mesh composite type, star‐mesh composite type, mesh type and ring type. When the total toll originating traffic becomes about 5 × 106 erl (it is about 106 erl at present), the differences in required numbers of circuits among four types except the ring type are within several percent.
Temperature‐stabilization of lumped‐element circulator in VHF region
Authors: Takeda Shigeru , Kawashima Masaharu 
Published: July 2007

AbstractPerformances of VHF lumped‐element circulators change sensitively by slight changes of 4πMs of garnets with temperature. Single‐tuned 100‐MHz circulators are studied. One experiment is to measure changes of external fields under the constant frequency condition with temperature; another experiment is carried out under the constant impedance condition. The former agrees well with theoretical predictions; the latter shows poor agreement.The parabolic compensation, which is the addition of several kinds of compensator alloys to magnetic circuits in parallel or in series depending upon the convex‐shape temperature characteristics of 4πMs, is very useful.
A synthesis of high‐order active R filter
Authors: Okine Mitsuo 
Published: July 2007

AbstractActive R filters consisting of resistors and finite‐GB‐product operational amplifiers have been reported in the literature. Most of them are of second order. Filter functions of higher order can be realized by second‐order blocks connected in cascade. A second‐order highpass filter or a filter with poles can not be cascaded if it is realized with two operational amplifiers since the filter output is not the amplifier output. This paper proposes a new active R filter which realizes an nth order filter function with n operational amplifiers. Lowpass, bandpass, and highpass filters with or without poles can be realized by selecting input and grounded terminals. The proposed method is featured with simple circuitry and ease of design. A fifth‐order lowpass filter will be shown to have theoretical and measured characteristics which are in good agreement.
The geometrization of the discriminal process model and the psychophysical functions
Authors: Takiyama Ryuzo 
Published: July 2007

AbstractThurstone's discriminal process model is geometrized and discussed from the information‐system theoretical point of view. That is, a probability density function (p.d.f.) based on the discriminal processes is defined in the state space (this is the concept of grasping simultaneously the physical stimulus and its response. A parameter space spanned by parameters of the p.d.f. is defined, and fundamental metrics are introduced into the space based on Fisher's information; thus, the space is considered to be a Riemannian space. In the space, the psychophysical functions are derived as certain geometrical invariants. As the results, when the “discriminal dispersion,” i.e., the distribution of the response (the response function) to the input stimulus is to be Gaussian, the power law and the logarithmic law are obtained as psychophysical laws with respect to the mean values of the distributions. From this, relations between difference thresholds, the discriminal process and the psychophysical function are clarified. At the same time, the formalization of the problems and conclusions in [2] are justified from the information‐system theoretical point of view. Further the functional forms of the response functions are also investigated, and it is shown that almost the same conclusions can be obtained even if the Gaussian assumption is repalced by the exponential, the two‐sided exponential, or the logarithmic Gaussian distributions.
Finite‐element analysis of anisotropic waveguides with tensor permittivity
Authors: Koshiba Masanori , Hayata Kazuya , Suzuki Michio 
Published: July 2007

AbstractA finite‐element expression for an anisotropic waveguide with a tensor permittivity is derived based on the variational expression in terms of all three components of the magnetic field. Since only the Hermitian condition is imposed on the permittivity tensor, the expression can handle an arbitrary anisotropic dielectric and a gyrostatic material. The spurious modes do not appear in the region of effective index of refraction larger than a specific value. From these points of view, the present finite‐element representation is considered to be one of the analysis methods useful for millimeter waveguides and optical waveguides. In this paper, a waveguide with a rectangular cross section is treated which is a fundamental structure for millimeter‐wave and otical integrated circuits. Specifically, rectangular anisotropic dielectric waveguides and rectangular gyrotropic waveguides are analyzed. The effect of off‐diagonal elements of the permittivity tensor on the guided mode characteristics is investigated.