bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral estimation method of a multistage nonstationary process and its application
Authors: Takizawa Yumi 
Published: July 2007

AbstractThis paper considers the time series observed through the nonstationary processes and proposes the multistage instantaneous maximum entropy method aiming at the inverse estimation of the behavior of the original process on the spectrum. The performance of the method is demonstrated and examples of useful applications are presented. To achieve the goal, the cascaded multistage AR process is considered as the model for the process from the excitation source of the time series to the observation. The excitation source is assumed as a simple white Gaussian noise.The response of the process is represented by a time‐varying lattice filter. The instantaneous value of the power spectrum is determined from the prediction error estimation function defined at a point on the time axis (instantaneous maximum entropy method, IMEM). Then the nonstationarity (time‐varying property) of the process is noted, and the separation of the connected processes is discussed. For this purpose, the nonstationary frequency axis of the two‐dimensional spectrum is considered based on IMEM.A filter to separate the considered process from others is designed. This filter passes the time‐varying component of the considered process but eliminates the time‐varying components due to the interference from other processes, based on thea prioriinformation concerning the time‐varying properties of the considered process.Finally, this paper presents the results of evaluation for the test using the artificial signal as well as the results of evaluation for two application examples. Comparing the result to that of the traditional method, the novelty and the usefulness of the proposed method are demonstrated. The system features are that the accumulation of the error in the multistage prediction can efficiently be suppressed using IMEM with the excellent prediction performance, which results in the high follow‐up ability to the time‐varying process, and the excellent spectrum estimation.
How intractable is the modified chosen discrete logarithm assumption?
Authors: Itoh Toshiya , Hosokawa Tomomi 
Published: July 2007

AbstractIn modern cryptologic theory, the design of cryptographic protocols is often based on the assumed difficulty of number theoretic problems. Especially, in order to prove the security of a cryptographic protocol based upon the assumed difficulty of a problem, a very important role is played by the legitimacy (as concerns the security of the cryptographic protocol) of that cryptographic assumption. Recently, Kurosawa, Ogata, and Tsujii proposed a new cryptographic assumption, the Chosen Discrete Logarithm Assumption (CDLA), and showed that any language in NP has a four‐move, zero‐knowledge interactive proof (ZKIP) under the CDLA.In this paper, we define the modified CDLA and consider its legitimacy. Our principal result (that the modified CDLA is not a legitimate cryptographic assumption) follows from a theoretical analysis of expected polynomial‐time algorithms and the concrete construction of an algorithm based on the Artin conjecture.
Highly sensitive ultrasonic flow velocity measuring method with FM component elimination
Authors: Tanisawa Shigeru , Hirose Haruo , Fukuzawa Hiroshi 
Published: July 2007

AbstractWe reported an FM ultrasonic velocimeter in which the frequency was varied by means of a ramp generator in order to reduce the number of multiple path signals. The generator requires good linearity and a necessity to change frequency with suitable speed, sometimes quite high. The authors experimentally confirm some standing wave suppressing effect using sinusoidal FM. For improvement of sensitivity, we used a second FM signal for computational processing in such a way that a new received signal with FM components eliminated was produced by adding both the received and the second FM signals. Flow velocity was thus derived from the phase between the new received and carrier signals. In elimination processing, the influence of the flow velocity and temperature change of fluid was compensated by a fixed command control system for residual FM components in a new received signal. From experiments, we were able to confirm the following:
The system is effective in elimination of FM components.
The measured phase shift is proportional to flow velocity and temperature change of fluid.
The sensitivity for flow velocity was improved considerably.
The control voltage of the fixed command control system was found usable for measurement of flow velocity, and a compensation method on the temperature change of fluid was introduced into this system.
Student modeling and its diagnosis based on synthesis of sets of production rules
Authors: Okamoto Toshio 
Published: July 2007

AbstractThis paper presents a method to model a student's understanding structure in an intelligent teaching system (ITS), especially the diagnosis of the comprehensive bug rule set. As the modeling of the student, the bug used in the problem‐solving process is identified by combining the primitive bug rules and the bug generation process of the student is represented by the production rules. Then a structural model for the bug generation is proposed based on a number of problem‐solving processes.The structure of bug generation is described from the viewpoints of redundancy, leap thinking, and ordering. As an actual example, the solution of the second‐order equation by factorization in elementary mathematics is considered. The construction of the intelligent CAI is discussed, including the proposed modeling technique. A highly practical system structure is presented which includes the teaching knowledge to make the student understand and master the operational skill of the world, although simple.
Synthesis of flow networks minimizing the sum of edge capacities
Authors: Kishimoto Wataru , Takeuchi Masashi , Kishi Genya 
Published: July 2007

AbstractSeveral synthesis methods to construct a flow network with the minimum sum of edge capacities for a given terminal capacity matrix have already been presented. However, there are networks that cannot be constructed by the known method.For the case where the given terminal capacity matrix is called elementary terminal capacity matrix, a synthesis method is presented that can construct any undirected flow network with the minimum sum of edge capacities. This paper is based on that synthesis method and presents a synthesis method that can construct any undirected flow network with the minimum sum of edge capacities for a given terminal capacity matrix with that matrix as the terminal capacity matrix.
Control limit analysis for the sidelobe reduction of ultrasonic transducer arrays
Authors: Kamata Hiroshi , Chubachi Noriyoshi 
Published: July 2007

AbstractThe effects of random response errors in amplitude and phase, element failures, and crosstalks on array gain and sidelobe level of ultrasonic transducer arrays are investigated by multivariate statistical analysis. The derived estimate equations are confirmed by simulation and measured data of various sonar arrays. The results show that the reasonable control limit of response errors for an infallible sidelobe reduction is not determined by the mean value of statistical sidelobes described in other papers but by the 95‐percent control line proposed in this paper.
Interpolated digital sinusoidal oscillators
Authors: Watanabe Eiji , Nakajima Nobuyasu , Saito Tetsuro 
Published: July 2007

AbstractThe digital sinusoidal oscillator considered in this paper is one of the signal sources employed in the digital signal processing system. A construction of the oscillator is discussed where the memory capacity is reduced and the increasing rate of the noise is suppressed by interpolating the output of the oscillator of table look‐up type or feedback type.A design method for the interpolation filter is presented first where no interpolation error is produced if the coefficient wordlength of the interpolation filter is infinite. Then, considering the case where the wordlength is kept finite, the hold‐type sampling expander is proposed where the waveform distortion is kept low compared with the traditional zero‐interpolation‐type sampling rate expander. The distortion in the proposed method is analyzed where the wordlength of the interpolation filter coefficient is kept finite, and the waveform distortion is shown to be low. The increasing rate of the round‐off error is examined by a computer simulation for the oscillator, which is obtained by applying the interpolation to the feedback‐type oscillator. The effectiveness of the interpolation is demonstrated.Finally, a construction of the block‐digital sinusoidal oscillator is shown with a smaller hardware complexity than in the traditional method, by constructing the block‐structured oscillator by realizing the proposed interpolation filter as a polyphase filter.
Spectral estimation of speech by mel‐generalized cepstral analysis
Authors: Tokuda Keiichi , Kobayashi Takao , Imai Satoshi , Chiba Takeshi 
Published: July 2007

AbstractThis paper proposes a spectral estimation method of speech based on mel‐generalized cepstral representation. The spectral estimation based on generalized cepstral representation is a method that unifies the cepstral method and the linear prediction method. By this method, the spectral model can be varied continuously from the all‐pole model to the exponential model.This paper also discusses the following: the method of spectral estimation, where the mel‐generalized cepstrum is used instead of the generalized cepstrum; the uniqueness of the solution for the minimization problem; the solution method; and the convergence of the solution. The proposed method has the same features as those of the method based on the generalized cepstrum where the spectral model can be varied continuously and the stability of the obtained transfer function is guaranteed. Another feature is that characteristics similar to the human auditory sensation, i.e., the high resolution in the low‐frequency range and the coarse resolution in the high‐frequency range, are obtained since the mel‐generalized cepstrum is used as the parameter, which is the generalized cepstrum defined on the mel‐frequency axis. Finally, the features and the effectiveness of the proposed method is demonstrated by analysis examples of the synthesized signals and natural speech.
Multiterminal source coding with linked encoders
Authors: Oohama Yasutada 
Published: July 2007

AbstractSlepian and Wolf considered a coding system (called SW system) for coding the multiterminal (information) source. This paper extends the SW system and defines anew a system (called SWL system) where encoders are mutually links. The problem of determining the optimal error exponent in the admissible rate region has not been answered completely for the SW system.It is shown in this paper that this problem can completely be solved for the SWL system. It is shown also that the optimal exponent can be achieved by the universal code. It is shown further that even if the encoders are linked, the admissible rate region is not enlarged and the reliability of the information transmission is not improved when the transmission rate is outside the admissible rate region. It is interesting to note that those results correspond in a sense to those for the channel with feedback.
Precision analysis of wiener kernels measured by cross‐correlation method
Authors: Yokota Yasunari , Toda Naohiro , Usui Shiro 
Published: July 2007

AbstractOne representation of the nonlinear dynamical system is the expansion by the functional series. Especially, the functional series expansion by Wiener has the feature that the kernel can be estimated relatively easily by inputting normal white noise. Consequently, it is used widely in the analysis of the neural system and other problems. However, few studies have been made on the quantitative evaluation of the accuracy of the kernel estimation because of its difficulty.This paper proposes a practical method of evaluating the accuracy of kernel estimation, thereby simplifying the problem by introducing appropriate restrictions and approximations into the kernel estimation. By this approach, the accuracy of kernel estimation can be represented as a function of the Volterra kernel of the system, the input power level, and the data length. The result is verified by a numerical experiment.It is shown that there exists the optimal input power level in the identification of the nonlinear system that maximizes the accuracy of kernel estimation. This is a new finding which has not been observed in the theory of the linear system.
A parallel algorithm fork‐way graph partitioning
Authors: Isomoto Kazunori , Wakabayashi Shin'Ichi , Yoshida Noriyoshi , Miyao Jun‐Ichi 
Published: July 2007

AbstractWith the recent development of semiconductor integration technology, the amount of data that must be handled in the layout design of VLSI is increasing rapidly. Even if the improvement of the processing speed of the computer in the future is considered, it is desired to develop a high‐speed layout algorithm compared to the conventional method.This paper discusses thek(> 2)‐way graph partitioning problem, which is one of the most basic problems concerning the layout design. A parallel algorithm is proposed. The general method to solve this problem has been to apply hierarchically the two‐way graph partitioning algorithm. In this method, the algorithm can easily be executed in parallel by operating a number of processors at each hierarchy. A problem then is the efficiency of the processor and the computation time.This paper considers thek‐way graph partitioning and proposes a new method called nonhierarchicalk‐way graph partitioning, aiming at the education of the computation time by parallel processing. In general, it is considered difficult to improve the speed sufficiently by the parallel processing, while maintaining the same accuracy of the solution as that of the sequential algorithm. In this paper, the effectiveness of the proposed algorithm is shown by a simulation experiment on the sequential computer.
A bayesian approach to an optimal ARQ number in data transmission
Authors: Sandoh Hiroaki , Nakagawa Toshio , Koike Shin‐Ichi 
Published: July 2007

AbstractThe automatic repeat request (ARQ) system is one of the means to achieve a high reliability in the data transmission system. In this system the data are retransmitted for a certain number of times when an error is produced due to the disconnection, noise, or distortion in the data communication channel; thus, the correct transmission is achieved.However, when a correct transmission cannot be achieved due to the incorrect data format or a fault of the channel, it is necessary that the retransmission be terminated as soon as possible, examine the data format or channel state, or switch the channel to another. In such a case, the behavior of the system depends greatly on the upper‐limit set for the number of repeat requests. At the present state, however, the upper limit for the number of repeat requests is determined empirically with little theoretical basis.This paper introduces the subjective probability from the viewpoint of the Bayesian theory for the probability that the data transmission is made physically impossible due to the fault of the channel or other factors. To set a reasonable value for the number of repeat requests, the expected cost for the data transmission is formulated and the optimal number of repeat requests to minimize the cost is investigated. By numerical examples, the features of the proposed method are discussed.
Theoretical analysis of nonlinear effects in surface acoustic waves on waveguide
Authors: Nakagawa Yasuhiko , Takanose Tsuyosi 
Published: July 2007

AbstractA structure with a ribbon‐shaped metal thin film on a highly coupled anisotropic piezoelectric substrate acts to concentrate the acoustic wave energy into the region with the thin film. A device making use of the nonlinear interaction of the surface acoustic waves propagating in opposite directions on this Δ v/v waveguide is the surface acoustic wave convolver. However, a theoretical analysis on its efficiency is not sufficient.In the present research, the guided wave characteristics of this Δ v/v waveguide are derived accurately so that the nonlinear components generated on the waveguide are computed. The generation efficiency of the surface acoustic wave at the second harmonic generated from this mechanism in the direction orthogonal to the waveguide is analyzed theoretically. The conversion efficiency of the split waveguide‐type convolver proposed previously by the authors can be derived quantitatively so that the evaluation of the surface acoustic wave nonlinear device becomes possible.
Test generation for sequential circuits based on boolean function manipulation
Authors: Choi Hoyong , Kohara Takashi , Ishiura Nagisa , Shirakawa Isao , Motohara Akira 
Published: July 2007

AbstractIn this paper, a test generation algorithm STAR for sequential circuits based on Boolean function manipulation is presented. Based on the product machine traversal (PMT) method, which generates test patterns using breadth‐first search of state‐pairs and an implicit state enumeration method of a product machine of fault‐free and faulty machines, STAR algorithm attempts to improve the computational efficiency by introducing a mixture of breadth‐first/depth‐first traversal based on the sequential depth, improvement on the image computation, and the computation of fault‐difference functions by the symbolic single‐fault propagation method. The results of the experiments on ISCAS 89 benchmark circuits show threefold improvement on the computational time over the simple PMT method.
The adhesion receptor CD155 determines the magnitude of humoral immune responses against orally ingested antigens
Authors: Maier Michael K. , Seth Sebastian , Czeloth Niklas , Qiu Quan , Ravens Inga , Kremmer Elisabeth , Ebel Maria , Müller Werner , Pabst Oliver , Förster Reinhold , Bernhardt Günter 
Published: July 2007

AbstractCD155, originally known as the cellular receptor for poliovirus, is the founding member of a subfamily of immunoglobulin‐like adhesion receptors. Apart from its function in establishing adherens junctions between contacting epithelial cells, the engagement of CD155 with two recently identified ligands, CD226 and CD96, mediates immunologically relevant processes such as NK cell‐driven killing of tumor cells in humans. Here we report on the generation and immunological analysis of mice constitutively deficient of CD155. Moreover, the expression profile of CD155 on hematopoietic cells has been determined using newly established antibodies. CD155‐deficient mice develop normally without displaying an overt phenotype. However, the animals are distinguished by distinct deficits in the development of a regular humoral immune response. Whereas systemic challenges revealed no differences, orally administered antigen evoked less efficient IgG and IgA antibody responses despite of normal IgM titers when compared to wild‐type mice. Therefore, CD155 may assist in an efficient humoral immune response generated within the intestinal immune system.
Synthesis of a 3‐Arylisoquinoline Alkaloid, Decumbenine B
Authors: Wada Yasuhiro , Nishida Naoto , Kurono Nobuhito , Ohkuma Takashi , Orito Kazuhiko 
Published: July 2007

AbstractThe synthesis of a 3‐arylisoquinoline alkaloid, decumbenine B, was accomplished in a reaction sequence based on the formation of an indolizine ring {dibenz[a,f]indolizin‐5(7H)‐one} followed by its cleavage at the amide bond, starting with an interaction of 5,6‐(methylenedioxy)isoquinoline with 2‐bromo‐5,6‐(methylenedioxy)benzoyl chloride in the presence of Bu3SnH.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of 4‐Amino Derivatives of 5‐Oxoproline
Authors: Krasnov Victor P. , Vigorov Alexey Yu. , Nizova Irina A. , Matveeva Tatyana V. , Grishakov Alexander N. , Bazhov Iliya V. , Tumashov Andrey A. , Ezhikova Marina A. , Kodess Mikhail I. 
Published: July 2007

AbstractThe possibility of obtaining the stereoisomeric derivatives of 5‐oxoproline and glutamic acid with a tertiary amino group at C‐4, using the nucleophilic substitution of bromine in dimethyl (2S,4RS)‐4‐bromo‐N‐phthaloylglutamate with secondary amines followed by resolution of diastereomers and removal of protecting groups has been studied. We have shown that the reaction with arylamines results in optically pure 5‐oxoproline derivatives in high yields. In the case of more basic amines, the reaction is accompanied by racemization, and the target products can be isolated only as diastereomeric racemates.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Theoretical Study of Tricyclo[4.2.1.02,5]non‐2(5)‐ene, Tricyclo[4.2.2.02,5]dec‐2(5)‐ene and Related Pyramidalized Alkenes
Authors: Fernández José A. , Vázquez Santiago 
Published: July 2007

AbstractHF, MP2 and CAS ab initio theory and B3LYP, B3PW91, SVWN and MPW1PW91 density functional theory were used to study a series of cyclobutenyl‐fused tricycles such astricyclo[4.2.1.02,5]non‐2(5)‐ene, tricyclo[4.2.2.02,5]dec‐2(5)‐ene and related compounds. Examination of the stepwise torsional potentials for 5–8 and 10–11 by scanning of the cyclobutene butterfly angles at the B3LYP/6‐31G(d) level revealed that there is only one minimum for each compound, with the cyclobutene bent in the endo direction in 5, 6, 10 and 11, and in the exo direction in 8. Examination of the stepwise heats of hydrogenation of 9 revealed that this compound, which displays a method‐dependent ground state, is antiaromatic. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Application of Sphere Cap Mercury Microelectrodes and Scanning Electrochemical Microscopy (SECM) for Heavy Metal Monitoring at Solid/Solution Interfaces
Authors: Daniele Salvatore , Ciani Ilenia , Baldo M. Antonietta , Bragato Carlo 
Published: July 2007

AbstractIn this paper, a combination of anodic stripping voltammetry (ASV) at mercury microelectrodes and scanning electrochemical microscopy (SECM) was employed to establish the concentration profiles of heavy metal ions at the soil/water interface of a natural sediment and bauxitic‐soil sample. Air dried soil samples were equilibrated with aqueous solutions containing 0.5 M NaCl plus acetate buffers or HClO4 at different concentrations to allow the achievement of different pH either in the aqueous phase or in the soil slurry. It was verified that mixing acidified aqueous solution and the soil without stirring led to concentration profiles displaying a maximum at the water/soil interface. This was explained as due to pH gradients that originated at the soil/water interface and within the soil slurries. On the other hand, mixing the soils and water solutions, under stirring for 24–48 h, provided almost uniform pH throughout the system. This allowed obtaining uniform metal ion concentrations within the soil slurries. For the evaluation of the concentrations, the anodic charge involved in the stripping step was utilized. The mercury microelectrode was standardized in a 0.5 M NaCl aqueous solution by performing calibration plots over the concentration range 0.1–500 μM. To evaluate the concentrations of the metal ions in the soil slurries, a procedure was developed to obtain the apparent diffusion coefficients of the metal ions, which depended on the physical properties of the soil such as porosity and tortuosity. The microanalytical methodology proposed here can be utilized for predicting the mobilization of trace elements from soils that comes into contact with acid rain.