bluuebunny/crossref_metadata_2025_split huggingface dataset:
Policing of realistic VBR video traffic in an ATM network
Authors: Rathgeb Erwin P. 
Published: July 2007

AbstractATM has been accepted by CCITT as the transport mechanism for the future BISDN and will also be widely used in future customer premises networks. Networks based on the ATM principle are expected to provide a very flexible communications infrastructure allowing customers to make effective use of a wide variety of offered services. To provide this flexibility with an acceptable quality of service while operating the network in an economic way, elaborate traffic management functions will be necessary to control the traffic flows within the network. This paper will study one of these functions—the so‐called ‘usage parameter control’ or ‘policing’ function—in some detail to illustrate some of the problems that arise and point out possible solutions. The mechanisms chosen to implement the policing function will be the ‘leaky bucket’ mechanism, the ‘jumping window’ mechanism and the ‘moving window’ mechanism. The input streams used to assess the mechanisms represent different types of video communication—videophone, video conference and entertainment video—coded according to different variable bit‐rate (VBR) algorithms. In contrast to most of the previous studies, where artificial, statistical traffic sources have been used, the sources used in this paper are directly based on measured ‘real‐life’ video data. This ensures that all the statistical properties of the actual traffic stream are preserved and allows identification of the different factors that influence the dimensioning and the performance of the policing mechanism. The results of this study show that the uncertainty about the key parameters at call set‐up and the considerable impact of single scenes make the proper dimensioning of policing mechanisms difficult. Furthermore, it seems not to be practical to use the long term mean bit‐rate as the key traffic control parameter for these sources. Results indicating that the long‐term cell loss ratio is not a sufficient measure for the quality of service are also presented. A comparison of the mechanisms shows that from a performance perspective, the ‘leaky bucket’ mechanism is superior to the two window mechanisms. This work is relevant to evolving standards for both BISDN traffic management and variable bit‐rate video coding.
Identification of novel genes expressed during mouse tooth development by microarray gene expression analysis
Authors: Pemberton Trevor J. , Li Fang‐Yuan , Oka Shoji , Mendoza‐Fandino Gustavo A. , Hsu Ya‐Hsuan , Bringas Pablo , Chai Yang , Snead Malcolm L. , Mehrian‐Shai Ruty , Patel Pragna I. 
Published: July 2007

AbstractTo identify genes heretofore undiscovered as critical players in the biogenesis of teeth, we have used microarray gene expression analysis of the developing mouse molar tooth (DMT) between postnatal day (P) 1 and P10 to identify genes differentially expressed when compared with 16 control tissues. Of the top 100 genes exhibiting increased expression in the DMT, 29 were found to have been previously associated with tooth development. Differential expression of the remaining 71 genes not previously associated with tooth development was confirmed by quantitative reverse transcription‐polymerase chain reaction analysis. Further analysis of seven of the latter genes by mRNA in situ hybridization found that five were specific to the developing tooth in the craniofacial region (Rspo4, Papln, Amtn, Gja1, Maf). Of the remaining two, one was found to be more widely expressed (Sp7) and the other was found to be specific to the nasal serous gland, which is close to, but distinct from, the developing tooth (Vrm). Developmental Dynamics 236:2245–2257, 2007. © 2007 Wiley‐Liss, Inc.
Learning rules of neural networks for inverse systems
Authors: Maeda Yutaka 
Published: July 2007

AbstractThis paper considers on‐line learning of neural networks for an inverse problem. A neural network must learn an inverse system of a static unknown system on the basis of an evaluation function that is a squared error between an output of the unknown system and its desired value.Usual learning methods need information about the sign of the sensitivity of the unknown system. This paper proposes learning rules that do not require the information about that sign. These rules utilize a perturbation signal. Rules with the perturbation on an input of the unknown system and a rule with it on each weight of the neural network are presented. The usefulness of these learning rules is confirmed via some numerical simulations.
Analysis of chaotic neuron models with information theory
Authors: Ishiyama Kunihiko , Itoh Susumu , Utsunomiya Toshio , Aihara Kazuyuki 
Published: July 2007

AbstractA one‐dimensional mapping of a chaotic neuron model which generates deterministic chaos is analyzed from the viewpoint of the information theory.First, the mutual information between the initial value and the value after iterations of the mappings is calculated, and it is shown that the information of the initial value decays almost exponentially. To examine the decaying behavior in detail, the dynamics of the chaotic neuron model is represented as the information flow of “0” and “1” in a bitwise space (register) and the behavior of the mutual information contained in each bit is examined. It is shown through this analysis that the information in the chaotic neuron model is maintained, being mixed and distributed among the bits. Moreover, the chaotic neuron model is compared with two typical chaotic dynamical systems with different information structures, i.e., the B‐Z mapping and the logistic mapping to clarify the information structure. Finally, it is shown for the system, where the chaotic neuron models are unidirectionally connected as a one‐dimensional network, that the information transmission is made possible by its peculiar information structure.
Reliability of maximum‐likelihood decoded codewords and its application to decoding of concatenated codes
Authors: Tanaka Hatsukazu 
Published: July 2007

AbstractThis paper attempts to improve the reliability of the maximum‐likelihood decoded codeword. The reliability function is defined anew based on the Euclid distance in the signal space and is derived for the case where the signal representation for the binary linear code is precisely specified. The traditionally well‐known Viterbi algorithm is modified to evaluate the reliability based on the proposed reliability function in parallel with the maximum‐likelihood decoding. This algorithm is called the modified Viterbi algorithm.To verify the usefulness of the newly defined reliability, the difference between the reliability and the likelihood is examined. The block‐error rate when the algorithm is applied to the decoding of the concatenated code is compared to the block‐error rates of the various conventional decoding methods. As a result, the block‐error rate is improved drastically by the decoding which effectively utilizes the reliability function; and it has been shown to be useful to introduce the concept of reliability into the decoding process.
Design of two‐channel perfect reconstruction QMF
Authors: Ikehara Masaaki , Yamashita Akinobu , Kuroda Hideo 
Published: July 2007

AbstractThis paper proposes a design method for the FIR two‐channel perfect quadrature mirror filter (QMF) with the linear phase. The two‐channel perfect QMF can be designed by Vetterli's method, where a system of equations representing the condition for the perfect reconstruction of the signal is solved. The filter designed by this method, however, does not, in general, have good frequency characteristics.This paper presents the design for the two‐channel QMF with a perfect reconstruction and a good amplitude characteristic. The method is based on Vetterli's method, and a constraint to approximate the amplitude characteristic in the frequency domain is added to the condition of perfect reconstruction in time domain. Then Remez' algorithm is applied to the derived system of equations.The construction of the two‐channel perfect QMF, when the coefficient is quantized, also is discussed. Furthermore, a method is shown in which the two‐dimensional (2‐D) perfect QMF is designed by applying the McClellan transformation to the obtained 1‐D QMF. The condition for the McClellan transformation for the perfect reconstruction is derived.
Vibration analysis of length extensional mode quartz crystal resonator with plural vibration bars
Authors: Kawashima Hirofumi , Nakazato Mitsuhiro 
Published: July 2007

AbstractA length extensional mode quartz crystal resonator of small size and good antishock performance and which functions at relatively low frequencies of 200 kHz to 1.536 MHz has been used in pagers and IC cards. An on/off repetition in quartz resonators of this type is common and therefore the start‐up transient performance becomes important.This paper describes a length extensional mode quartz crystal resonator with plural vibration bars which has a short start‐up time. The objective of this paper is to clarify both theoretically and experimentally motional inductance L1, frequency characteristics and temperature dependence of resonance frequency, and also electric properties of the resonator.Motional inductance L1 is derived first. Especially, L1 is found theoretically to be inversely proportional to the number of bars. Next, a vibration analysis of bars and supporters is made by taking into account the lateral motions based on an energy method and then a frequency equation is derived. The frequency characteristics, temperature dependence of resonance frequency, and electric properties are analyzed and compared with experimental results. The calculated results are found to be in agreement with the experimental ones. Finally, it is shown that a length extensional mode quartz resonator exhibits a short start‐up time, since L1 and R1 are compared to the single‐bar case. Such resonators are believed to be manufactured in a small form and also exhibit a good anti‐shock performance since vibrational and supporting portions can be made as one solid body by an etching method.
Measurement of leaky surface acoustic wave velocity using interdigital transducer in a layered structure composed of piezoelectric ceramic and fused quartz
Authors: Toda Kohji , Sawaguchi Akihiro 
Published: July 2007

AbstractAn ultrasonic system for measuring a leaky surface acoustic wave (SAW) velocity is described. A leaky SAW transducer consisting of a piezoelectric ceramic thin plate, an interdigital transducer (IDT), and a fused quartz plate is used in this system. A longitudinal wave which is reradiated from a test sample surface into a water layer is detected as electric signals having different delay times received at two different IDTs placed on a substrate surface. A phase difference between two delayed signals depends on the leaky SAW velocity. It is essential in this measurement method that an incident angle of an ultrasonic beam be nearly equal to the Rayleigh angle. The present method using a layered structure leaky SAW transducer has the advantage of a wider range of detecting SAW velocities, compared to a conventional single‐layer SAW one. Experimental results for a 128° rotated Y‐cut‐X propagation LiNbO3 plate and a glass plate are discussed. The layered structure leaky SAW transducer is useful for nondestructive evaluation of piezoelectric as well as nonpiezoelectric substrates.
Systematic consideration of the superiority of generalized linear interpolation approximation
Authors: Kida Takuro , Mochizuki Hiroshi 
Published: July 2007

AbstractThis paper considers the set of waveforms for which the weighted power‐of‐p(1 < p < +∞) integral of the Fourier spectrum is bounded. Since different weight functions can be used in different frequency bands, as long as they are positive, the restriction of the waveform by the power‐of‐pintegral is sufficiently general. It is assumed that the waveform belonging to such a set is added to several given linear time‐invariant filters. A theory of the optimum approximation of the original waveform is established using the sampling sequences of the corresponding outputs. The measure of the approximation error is defined as the upper limit of the absolute value of the difference between the original and the approximating waveforms when the original waveforms are changed one by one over the whole set of waveforms.Considering the sampling points, which substantially affect the approximation at a fixed timet, a theorem is presented which indicates that there exists a waveform which has zero value at all such sampling points and has the absolute value of the approximation error which reaches the above upper limit. It is shown also that a similar result can be established for the multidimensional waveform.In this paper, it is shown that the proposed method of linear approximation is better than any other approximation using the same sample values, including the nonlinear signal processing, as long as the forementioned set of waveforms and the measure for the approximation error are considered.
A least‐squares adaptive filter with complex coefficients for ill‐conditioned adaptive equalization
Authors: Shimamura Tetsuya , Suzuki Jouji 
Published: July 2007

AbstractThis paper presents a least‐squares adaptive equalizer that provides good performance even in an ill‐conditioned environment where the channel distortion is rather severe. Using complex‐valued tap coefficients and halving the order of the transversal equalizer result in a substantial reduction in the condition number of the input correlation matrix composed of input signals to the equalizer. The input and output signals for the equalizer are transformed into analytic signals. Then a sampling operation of decimation by a factor of two is performed. Adaptive filtering is performed based on complex arithmetic. Compared with commonly used real‐valued adaptive equalizers, accuracy of the estimation of tap coefficients is improved substantially and the computational burden per time is reduced. Computer simulations will show the effectiveness of the proposed adaptive equalizer.
Deriving the complete weight distribution of reed‐solomon codes
Authors: Tokiwa Kin‐Ichiroh , Tanaka Hatsukazu 
Published: July 2007

AbstractThe weight distribution of a code usually is investigated on the basis of Hamming weight. For such non‐binary codes as Reed‐Solomon (RS) codes, therefore, all nonzero components of codewords are regarded as identical. To describe the structure of nonbinary codes in more detail, each nonzero component should be distinguished from the other. This requirement can be met by the complete weight distribution (CWD).Recently, Blake and Kith and the present authors derived independently the CWD for a special class of RS codes. However, the derivation of the CWD for general RS codes remains a difficult problem. This paper discusses the problem of obtaining the CWD for general RS codes. To make this process easier, three unique sets of codewords which should be examined are defined first. Then it is shown that the CWD can be derived from such unique sets of codewords. Finally, a relationship between the CWD for RS code of dimension k and that of dimension k + 1 is considered.
Floating‐electrode‐type SAW unidirectional transducers using leaky surface waves and their application to low‐loss filters
Authors: Takeuchi Masao , Yamanouchi Kazuhiko , Murata Kenji , Doi Kenji 
Published: July 2007

AbstractTo realize surface acoustic wave (SAW) filters with low‐loss and wide bandwidth for mobile communications, a floating‐electrode‐type unidirectional transducer (FEUDT) using internal reflection is discussed. The proposed structure for FEUDT has an advantage of manufacturability and also for high‐frequency performance exhibiting a second harmonic operation better than a fundamental mode.This paper describes both a theoretical and experimental result. A leaky surface acoustic wave (LSAW) of SH‐wave type using 41 °YX LiNbO3substrate, the velocity of which is much faster than that for a usual Rayleigh wave and has a largeK2is used. A second harmonic FEUDT suitable for this wave is obtained theoretically by using the Green function method. The result is in good agreement with experiment.An SH‐type LSAW is more sensitive to a surface boundary condition of a substrate compared to the usual Rayleigh wave and thus the boundary condition for a low‐loss filter is very important. This is discussed both theoretically and experimentally. It is found that an open grating is the best for a propagation path if one considers the mode conversion of LSAW excited by a transducer. A prototype filter has been fabricated. The insertion losses of 2.6 dB and 2.8 dB at the center frequency of 360 and 700 MHz, respectively, are obtained successfully.
High‐frequency IIR switched capacitor filter using parallel cyclic‐type circuit with low‐power consumption
Authors: Hirata Yoshinori , Takahashi Nobuaki , Kato Kyoko , Takebe Tsuyoshi 
Published: July 2007

AbstractFIR transversal filters have been proposed using a parallel cyclic‐type circuit configuration which alleviates the performance degradation at higher frequencies due to the finite gain‐bandwidth product of op amps in switched capacitor filters. A parallel cyclic‐type circuit realizes the delay and weighting of the input signal with switches and capacitors without op amps. It is also of low‐power consumption because it requires only one op amp for its adder.This paper describes a method to implement direct form I IIR filters using a parallel cyclic‐type circuit. The performance degradation caused by the finite gain bandwidth product of the op amp and by parasitic capacitances is analyzed, both for the canonical circuit with the delay element using op amps and for the parallel cyclic‐type circuit. Also, a parallel cyclic‐type circuit is proposed for high‐frequency operations containing multiple adders. This circuit incorporates a novel feedback scheme using the “Look Ahead” calculation method. Finally, through experiments, the performance improvement by the parallel cyclic‐type circuits over the canonical and biquad circuits is demonstrated.
Signal propagation timing check system in multilevel sequential circuits
Authors: Nakamura Yatsuka , Nishiyama Takaya , Fuwa Yasushi 
Published: July 2007

AbstractThis paper presents the concept of the timing vector as well as the related techniques which are useful in checking the synchronization and the timing in the multistage sequential circuit. In each of the sequential circuits, the output period where the output is unstable and the sense period where the input must be stable are considered. The proposed method is based on the property that, if the output period of the preceding stage in the cascaded circuits overlaps with the sense period of the succeeding stage, the signal cannot be propagated properly. The existence/nonexistence of such an overlap is checked.First, the output period and the sense period of the sequential circuit are modeled in a form which does not depend on the frequency and the duty‐ratio of the clock given to the circuit. In the check process, this clock information is given to the circuit model. A timing belt is constructed where the output and sense periods of each circuit are developed on the real time‐axis, and it is checked whether or not an overlap exists in each circuit. The feature of the method is that the timing check of the cascaded sequential circuit can be executed completely with a high speed. Using the program constructed based on the proposed method, the sequential circuit actually is checked and the usefulness of the method is verified.
Dynamic measurement of nonlinear constants of PZT ceramics
Authors: Cho Yasuo , Matsuno Fumihiko 
Published: July 2007

AbstractThe dynamic measurement technique of adiabatic nonlinear constants in piezoelectric materials used in elastic devices is discussed. The present technique deals with the FM wave whose frequency varies corresponding to a physical quantity which changes sinusoidally. Using this method, measurements of a change in velocity and dielectric constant due to an applied ac electric field and also of a change in dielectric constant due to sinusoidally applied stress are made. In this method one can measure physical quantities depending on their orders responding to an applied field separately and can obtain constants of the orders (third of fourth order). Also, this technique can distinguish a change in velocity and dielectric constant due to temperature variation from those resulting from a nonlinear effect. Using this unique feature, measurements of velocity and dielectric constants with electric field at various temperatures were made. The temperature dependence of linear and nonlinear constants of the third and fourth order in PZT ceramics was discussed.
A class of fixed‐point problems on graphs and iterative solution algorithms
Authors: Tamai Tetsuo 
Published: July 2007

AbstractA family of well‐known problems on graphs including the shortest‐path problem and the data flow analysis problem can be formulated as a fixed‐point problem. The lattice is used to represent the algebraic structure of information and the problem is formulated with fixed‐point equations where unknown variables that label vertices of the graph take values over the lattice.Then a practical solution algorithm based on the iterative approach that solves the unified problem is given. When applied to the shortest‐path problem, the algorithm is equivalent to the well‐known potential method but its validity for the generally formulated problem is not trivial. The correctness and termination of the algorithm within a general framework is proved.Finally, the formulation is compared to other formulations and the most fundamental structure of the problem is discussed. The relation between the general algorithm and various existing methods for each specific domain are analyzed and it is shown that for the data flow problem, the general algorithm practically is improving existing iterative methods such as Kildall's and that of Hecht and Ullman.
Delta function model analysis of SSBW spurious responses in SAW devices
Authors: Hashimoto Ken‐Ya , Yamaguchi Masatsune 
Published: July 2007

AbstractThis paper considers the characterization of surface skimming waves (SSBW) by two newly defined parameters, i.e., effective electromechanical coupling factor and critical length. The parameters are estimated easily by the effective permittivity and are directly applicable to the delta function model analysis. Experiments on a TV‐IF SAW filter agreed well with the analysis. In addition, these parameters for SO2/36° KY‐LiTaO3structure were estimated. It is shown both theoretically and experimentally that the SSBW responses can be suppressed by depositing SiO2with appropriate thickness.
Narrow‐gap and multiphase interdigital transducer using anodic oxidation
Authors: Odagawa Hiroyuki , Meguro Toshiyasu , Doi Kenji , Yamanouchi Kazuhiko 
Published: July 2007

AbstractA method of fabricating a narrow‐gap interdigital transducer and of a multilevel interconnection using anodic oxidation is discussed, which is a key technology for SAW devices with high performance. This process can cope with the two problems of its high‐frequency application and fabrication of an advanced electrode structure. As an example, this method is applied to a group‐type unidirectional transducer (GUDT). The process for a high‐frequency performance by having a narrow‐gap structure and no loss without meander‐line electrodes is proposed.A prototype filter with GUDT has been fabricated by using this method and a good result of an insertion loss of 2 dB at a center frequency of 700 MHz was obtained. This result has confirmed that GUDT is useful for low loss and with very small ripple where no meander‐line electrode is used. The present method has demonstrated its high applicability.