bluuebunny/crossref_metadata_2025_split huggingface dataset:
A piecewise‐linear homotopy method for nonlinear programming
Authors: Yamamura Kiyotaka , Arai Kaori , Kiyoi Masahiro 
Published: July 2007

AbstractIn nonlinear programming problems, an objective function f(x) is optimized (maximized or minimized) subject to some constraints. Such problems are also called constrained optimization problems. Most of the algorithms in nonlinear programming are classified into two categories: 1) transformation methods; and 2) projection methods.The homotopy methods, which are the subject of this paper, belong to the category of projection methods. The main feature of the homotopy methods compared with other projection methods is that they are good at global convergence (which is lacking in most of the projection methods) but are not good at convergence speed (which is the strong point of most of the projection methods).This paper discusses the homotopy methods in nonlinear programming and show that the piecewise‐linear homotopy method using the Newton homotopy and polyhedral subdivision is very effective for solving nonlinear optimization problems. A new algorithm is proposed that exploits the partial separability and linearity of the Kuhn‐Tucker equations (which appear in the nonlinear programming problems). By this exploitation, the computation efficiency is improved markedly compared with the conventional homotopy methods using simplicial subdivision. Moreover, the proposed algorithm converges quadratically, thus accurate solutions can be obtained rapidly. It is proved also that the proposed algorithm is globally convergent for the constrained convex optimization problems. Except for the shortcoming that the programming is complicated, the proposed algorithm has wellbalanced effectiveness.
Evaluation of smoothed group delay spectrum distance measure in speaker‐independent speech recognition
Authors: Umezaki Taizo , Singer Harald , Itakura Fumitada 
Published: July 2007

AbstractThe smoothed group delay spectrum distance (SGDS) measure is evaluated in speaker‐independent recognition experiments. First, the appropriate level of smoothing of the group delay spectrum (GDS) is investigated by adding noise, etc., to the input speech. Then a comparison with the speaker‐dependent case is made. An experiment is reported in which, for low amplitude parts of speech (e.g., unvoiced speech), the standard (LPC) distance measure is used in the interframe distance calculation instead of the SGDS distance measure. This method prevents a loss of recognition accuracy due to too strong an emphasis on certain spectral elements and a consistently high recognition accuracy can be achieved.Finally, evaluate the SGDS distance measure is evaluated where the GDS is represented in the spectral domain as a discrete Fourier transform (DFT) of the LPC coefficients. In comparison to the SGDS which was calculated by weighting the LPC cepstrum co‐efficients, computation time and memory space can be reduced without loss of recognition accuracy. Furthermore, a low bit quantization of the GDS is reported and a high recognition rate is achieved with only 32 bits per frame.
Design of 2‐D separable‐denominator digital filters using impulse response grammians
Authors: Hinamoto Takao , Toda Hideki , Yamaguchi Ryuji 
Published: July 2007

AbstractA technique is developed for designing 2‐D separable‐denominator digital filters in the spatial domain. First, a given 2‐D FIR digital filter is realized in a canonic form by the Roesser model whose transfer function is separable in the denominator. Then, the reduced‐order model is obtained using eigenvalue‐eigenvector decomposition on the impulse response Grammians derived from the realization.The proposed technique utilizes the impulse response Grammians considered here for 2‐D separable‐denominator digital filters, which are extensions of those proposed for single‐input/single‐output 1‐D linear systems. The stability of the resulting filter is always guaranteed. Finally, two numerical examples are given to illustrate the utility of the proposed technique.
Some properties of sequential‐association type neural networks
Authors: Yanai Hirofumi , Sawada Yasuji 
Published: July 2007

AbstractAssociation is a fundamental aspect of information processing in neural networks. In order to elucidate the relationship between sequential association capabilities and the constituent elements of a binary‐output neural network model, we discuss here the response characteristics of elements (neurons) and the relationship between the adaptation (learning) rule for connection strengths (synapse weights) and sequential association capability. We discuss how sequential associations depend on the element‐characteristic, for example, the role of self‐connections in sequential associations of correlated patterns.For adaptation rules which do not depend on the adaptation state of the network, we consider one based on a multiple of the current activation of an element (basically the Hebb rule) and one which is a multiple of the change in activation. The former rule has high capability in ideal circumstances, but we show that the latter rule is more robust. There have been many papers concerning the case in which the qualities of the patterns to be stored are known a priori, but here we also discuss flexibility (robustness) toward patterns which differ from those which are expected.
Study of the superiority of generalized linear interpolation approximation
Authors: Kida Takuro , Mochizuki Hiroshi 
Published: July 2007

AbstractConsider a set of waveforms whose Fourier spectra are band‐limited within a certain frequency band. We assume that the weighted Lp integrals (1<p< +∞) of the Fourier spectra are bounded with respect to a given weight function. We present a method which optimally approximates the original waveform contained in the above set with respect to an appropriate measure of error. We use a series of sample values of the outputs obtained when the waveform passes through a given finite number of linear time‐invariant filters.Here, we establish a theorem which shows that there exists a waveform among all those waveforms whose sample values at the sample points are all zero, whose error is a maximum at some arbitrary fixed time t. Further, under the condition that p = 2 and the sample values, which are in general not all zero, are given, we prove that the upper limit of approximation error is proportional to the maximum of absolute value of the approximation error described above. As a result, it is shown that as long as the set of waveforms and the measure of approximation error mentioned above are adopted, the proposed linear approximation method is superior to all other approximation methods even including, for example, non‐linear signal processing using the same sample values. Further, at the end of this paper, we show that our argument can be applied to more general sets of waveforms.
Functional information extraction from combinational circuits
Authors: Ohmura Masahiko , Yasuura Hiroto , Tamaru Keikichi 
Published: July 2007

AbstractThis paper proposes a technique of functional information extraction which transforms design description at the logic circuit level in the LSI design process to a description at functional level. This technology is considered to be a powerful means of logic design verification similar to the circuit extraction technology already in practical use for layout design verification. Moreover, by automatically generating function description language from given circuit description, it can be used in functional and fault simulations and is useful in reusing circuits.An extraction technique of logic and arithmetic functions of combinational circuits is investigated herein. As internal representation of logic functions, binary decision diagrams are used for efficient treatment. For extraction of arithmetic functions, a technique of first extracting logic functions, and then representing them by arithmetic expressions is used. This technique has a characteristic that the same function description is obtained from circuits with the same functions even though their circuit structures are different. Therefore, functional information extraction independent of circuit structure can be done.This paper describes first the extraction of logic functions, which is the basic technique, and then explains the arithmetic function extraction technique. Finally, some concrete examples are evaluated.
Automatic design of a parallel/pipelined VLSI architecture for signal processing
Authors: Yokoyama Yutaka , Miyanaga Yoshikazu , Tochinai Koji 
Published: July 2007

AbstractThis paper discusses the system for automatic design of the parallel/pipelined VLSI architecture based on the signal processing algorithm. A new design language is introduced into the proposed system. The language is defined so that the time variable used in the signal processing algorithm can easily be described. The system has a high modularity, and the modules can be combined into a hierarchical structure. By this scheme, the algorithm with a high complexity can easily be described.The algorithm inputted to the system may contain a backward time‐flow of the delayed data as well as a complex hierarchical structure, which makes it difficult to execute the data‐flow graph obtained directly from the algorithm by the parallel/pipelined structure.From such a viewpoint, this paper adopts the following procedure. The data‐flow graph is derived from the given algorithm. A sufficient parallelism and a highly efficient pipelined mechanism are extracted from the obtained graph. Then the parallel processing architecture is designed. As an example, a parallel/pipelined architecture is designed for a simple adaptive signal processing algorithm. The result is compared with the traditional design examples, and it is shown that the efficient data‐flow architecture is derived.
Road noise barriers as sound radiation systems
Authors: Kagami Shin , Moriyoshi Akihiro , Fukai Ichiro 
Published: July 2007

AbstractRoad traffic noise has become a significant societal problem and the noise barrier as one remedy is studied acoustically. Traditionally, as a theoretical background for installing the noise barrier, the diffraction theory of the acoustic wave by a screen has been employed. In this paper, however, the noise barrier and the road structure on which a vehicle is a noise source are treated as one acoustic radiating system. By means of the boundary element method useful for an open‐region problem, a two dimensional analysis is carried out.From the results of the analysis with the cross‐sectional shape of the noise barrier and the frequency as parameters, it is found that a resonance is generated for a shape with parallel faces and the noise may be spread a large distance away in conjunction with the diffraction at the edge of the noise barrier. If an unrealistic containment is not expected and a horn shape is employed, the noise can be radiated upward in the direction normal to the road surface and the diffraction does not become significant. The frequencies studied were 150 to 300 Hz which are bothersome to the human ears.
A design of wide‐bandpass filter using transmission lines and lumped capacitances
Authors: Sekine Toshikazu , Nakamura Takashi , Yokokawa Senji 
Published: July 2007

AbstractThis paper discusses a design method for the small‐sized wide‐bandpass filter, which is a circuit composed of distributed‐constant transmission lines and capacitors. In this method, the wide‐bandpass filter is designed as follows.The lumped‐constant LC lowpass filter is used as the prototype. To derive the mixed circuit containing transmission lines and capacitances from the prototype circuit, although approximately, the cascade section of the mixed circuit is transformed into the equivalent π‐type circuit. Then, a new frequency transformation is considered to arrive at the wide‐bandpass filter. The mixed circuit designed by this method contains cascade transmission lines and the parallel short stubs, and the cascade transmission lines have the same length. The condition for minimizing the approximation error in the design is discussed. The range of the bandwidth ratio that can be designed is examined, and the usefulness of the proposed design method is verified by experiment.
Chaos in a four‐dimensional autonomous circuit with two diodes
Authors: Nishio Yoshifumi , Mori Shinsaku , Inaba Naohiko 
Published: July 2007

AbstractThis paper proposes a 4‐D autonomous circuit represented by a constrained equation containing two small parameters. Various chaotic phenomena generated in this circuit are rigorously analyzed. This circuit contains two diodes and their ON resistance corresponds to the parameter. Here, an ideal case is considered in which the ON resistance of the diode is 0. In such a case, the circuit equation can be represented by a 2‐D equation in a piecewise manner and the Poincaré map can be extracted as a 1‐D map. The shape of this map is that of logistic map. By means of the latter, the generation of the period‐doubling bifurcation and chaos observed in the circuit experiment can be rigorously explained.
Computational complexity of the homotopy method for calculating solutions of strongly monotonic resistive circuit equations
Authors: Makino Mitsunoai , Oishi Shin'ichi , Kashiwagi Masahide , Horiuchi Kazuo 
Published: July 2007

AbstractA priori estimation is presented for a computational complexity of the homotopy method applied to a certain class of hybrid equations for nonlinear strongly monotonic resistive circuits.First, an explanation is given as to why a computational complexity of the homotopy method cannot be a priori estimated for calculating solutions of hybrid equations in general. In this paper, the homotopy algorithm is considered in which a numerical path‐following algorithm is executed based on the simplified Newton method. Then by introducing Urabe's theorem, which gives a sufficient condition guaranteeing the convergence of the simplified Newton method, it is shown that a computational complexity of the algorithm can be a priori estimated when applied to a certain class of hybrid equations for nonlinear strongly monotonic resistive circuits whose domains are bounded.This paper considers two types of path‐following algorithms: one with a numerical error estimation in the domain of a nonlinear operator; and one with a numerical error estimation in the range of the operator.
Enhanced circuit simulation: Expectations, problems, implementation, and integration
Authors: Saleh Resve A. , Inoue Takahide , Ido Sachihiko 
Published: July 2007

AbstractDuring the late 60s and throughout the 70s, the field of circuit simulation has advanced in step with the increase in the use of analog integrated circuits. The general purpose circuit simulator SPICE was released in this period. During the 80s, in addition to pure analog circuits, digital and mixed analog‐digital VLSI circuits also saw dramatic increases in usage. In this paper, we will discuss the roles that manufacturers are coming to expect that circuit analysis techniques will play in the development of VLSI circuits. Specifically, we will consider the limitations that general purpose simulators like SPICE have and enhancements needed in the future. We will consider these limitations by specifically considering problem analysis methods developed for each limitation. Finally, we present ideas for future work.
Acquisition of internal representation by multilayered perceptrons
Authors: Irie Bunpei , Kawato Mitsuo 
Published: July 2007

AbstractOne of the characteristics of the PDP model (multilayer perceptron with backward error propagation learning) is thought to be its ability to automatically find a mapping between inputs and outputs based on input‐output vector samples describing that mapping. However, since in the mapping the values of representative points are determined by table lookup, and the values of other points are determined by interpolation between them, it can be viewed as one type of Memory Based Reasoning. On the other hand, it is thought that the PDP model has the ability to extract features from the input vector.In this paper, the forementioned two points are investigated completely and it is demonstrated that entirely different results are obtained when the internal representation differs, even if the input data are exactly the same. It is stipulated that information processing in the PDP model is a process that carries out a transformation which represents the input vector distribution in an optimal metric space (internal representation) and interpolates that metric space. This internal representation acquisition capability is demonstrated by means of a simple simulation.
A fuzzy selection method for generated equivalent logic circuits
Authors: Wakabayashi Satoshi , Ishikawa Hiroyuki , Dang Ryo 
Published: July 2007

AbstractIn the design of logic circuits, it is not always true that the circuit constructed by the designer is the optimal one. From such a viewpoint, this paper proposes a method in which the first designed circuit is expanded backwardly, i.e., from the output back to the input, and more than one equivalent circuit of the same function is resynthesized and the one best satisfying the requirements is determined and adopted.In the proposed method, a fuzzy reasoning is introduced in the decision process. In this scheme, such requirements as the delay time, power consumption and the chip area are handled by the fuzzy reasoning. A selectability index known as “selection criterion value” is given to each generated circuit, and the objective logic circuit is selected according to this index.Such requirements as delay, etc., have different units and are often in a trade‐off relation. Therefore, these requirements are represented as relative values and are considered as circuit selection parameters in the fuzzy reasoning. Such parameterization enables easy understanding of the features of each circuit. It is easy also to decide which of the parameters of the trade‐off relation is to be emphasized in the selection process.
Performance analysis of disk allocation methods for cartesian product files by using error‐correcting codes
Authors: Ito Minoru , Kasami Tadao , Kataoka Mituteru , Fujiwara Toru , Okui Jun 
Published: July 2007

AbstractThe Cartesian product file is an efficient method of handling the partial match queries to retrieve a record from a file, which has the specified values for the specified attributes. The optimal processing efficiency for the query is realized in an environment where multiple disks with parallel access are employed by allocating the Cartesian product file among the disks in a distributed way so that the buckets which may contain the record satisfying the specified condition are read uniformly from the disks.Recently, Faloutsos and Metaxas proposed a method whereby the Cartesian product file is allocated to the multiple disks using the error‐correcting code. In this paper, using their method of allocating the Cartesian product file in the multiple disks, the following is presented: (1) the sufficient condition for the queries so that the processing efficiency is strictly optimal; 92) the necessary and sufficient condition for the code that realizes the allocation with the strictly optimal efficiency for any queries; and (3) the expression for the average response time for the query by which we can easily compute the average response time when the weight distribution of the code (or that of the dual code) is known. Through several examples, it is shown that the average processing time determined from the expression is very close to the theoretical lower bound.
Estimation errors of volterra kernels measured by use of nonwhite input
Authors: Yokoyama Makoto , Watanabe Atsushi 
Published: July 2007

AbstractIt is well known that employment of nonwhite input in system identification often causes large estimation errors. While the mechanism of inducing these errors has been well understood for linear system identification, it has not been made clear yet for nonlinear systems.This paper analyzes this mechanism for nonlinear system identification with Volterra functional series models. A vector space approach gives a clear physical interpretation of the error generation from a viewpoint of the excitation intensity of the input against the identified system. Based on this analysis, new algorithms of reducing estimation errors are proposed.
Estimation of impulse response by using a nonwhite input—analysis of estimation errors by geometrical approach
Authors: Yokoyama Makoto , Watanabe Atsushi 
Published: July 2007

AbstractWhen the ordinary least‐square method is applied in the estimation of the impulse response of the linear system using a nonwhite input, the result is affected greatly by the observation noise and the error in the numerical calculation, and the accuracy of the estimation is greatly deteriorated.This paper presents a mathematical analysis based on a geometrical approach for the error generation mechanism and provides a clear physical description from the standpoint of the system identification. It is shown that the nonwhite input has the following problem.The excitation turns out to be weak for the linear system in which the impulse response vector corresponds to the eigenvector for a small eigenvalue of the autocorrelation matrix. This weakness of the excitation is the major cause of the deterioration of the estimation accuracy in the ordinary least‐square method.Based on those results, a new physical interpretation is given to the eigenvalue truncation method and the regularization method, which are already proposed as improvements of the ordinary least‐square method. The proposed error analysis can also be considered as the basic theory which can be applied not only to the estimation of the impulse response, but also to the parameter estimation of the transfer function model and the design of the optimal input for the identification.
Effects of finite register length in the fast hartley transform
Authors: Furuya Ken'Ichi , Date Hikaru , Fukudome Kimitoshi 
Published: July 2007

AbstractThis paper discusses the effect of finite register length on the computation accuracy of the fast Hartley transform (FHT) and derives a theoretical statistical expression for the mean‐square computation error. Theoretical proofs are presented which show that: (i) the computation error of a fixed‐point FHT is proportional to the square of the number of data (N); (ii) the computational error is proportional to N if scaling is used to prevent an overflow in the fixed‐point FHT; (iii) the computational error is proportional to log N in the case of the floating‐point FHT; and (iv) the computation error is halved by increasing the register length by 1 bit. An experiment was conducted to verify those properties.
Finite element analysis of focusing transducers and their responses
Authors: Tsuchiya Takao , Kagawa Yukio , Yamabuchi Tatsuo 
Published: July 2007

AbstractFor the accurate field analysis of focusing ultrasonic transducers, an acoustic lens or a waveguide system including a piezoelectric driving resonator and its radiation field must be fully considered. The finite element method is applied to analyzing the sound field from the acoustic lens driven by a piezoelectric disk. The steady‐state sound field is examined for the lens system of some configurations. First, a lens‐water coupled system is considered; and then the vibration of the piezoelectric resonator is also included. It is shown that the presence of the piezoelectric vibrator affects the focusing capability or resolution. The time‐dependent field is then demonstrated by the use of an inverse Fourier transform technique for an electric impulsive excitation. Comparison is made with the steady‐state response for the focusing capabilities. It is confirmed that the present technique is useful for the computer‐aided design of focusing transducers.