Showing papers by "Nagoya Institute of Technology published in 1977"

Pattern classification of the phonocardiogram using linear prediction analysis.

Abstract: The paper reports some results with phonocardiogram pattern classification. Linear prediction analysis was applied to extract the spectral pattern from phonocardiogram signals, a relatively new technique. In this examination, 29 design samples are classified correctly, except for three samples; and 19 test samples correctly, except for five samples. The characteristics for each class are well extracted and the results of the classifications are good. The efficiency of the spectral features for phonocardiogram classification has been confirmed experimentally.

Dependency as a measure to estimate the order and the values of Markov processes

Abstract: To evaluate the order and the values of Markov properties of the time series of events, we have proposed a statistical measure "dependency":D m = (H 0 ?H m )/H 0 , whereH 0 andH m are Shannon's entropy and them-th order conditional entropy, respectively. It is indicated that $$\tilde D_m = \sum\limits_{v = 1}^m {(\hat D_v - \bar D_v^{sh} } )$$ is a better point estimator ofD m, giving a total value of them-th order Markov process. Here $$\hat D_m $$ and $$\bar D_m^{sh} $$ are the estimate ofD m and the arithmetic mean of $$\hat D_m^{sh} $$ when them-th order shuffling is made many times for a given observed series, respectively. The value $$\hat D_m - \bar D_m^{sh} = d_m $$ represents Markov value of the orderm. Under the assumption that the series has continuous variables and the normal distribution, simplified dependency is defined by[Figure not available: see fulltext.], where |S m | is the determinant of serial correlation coefficients. It is shown that[Figure not available: see fulltext.] is practically useful for the estimation of the order and the values of Markov processes with small sample size. It is also indicated that[Figure not available: see fulltext.] analysis is basically equivalent to the least mean-square analysis of autoregressive models.

Free‐radical polymerization of methyl methacrylate initiated by N,N‐dimethylaniline

Abstract: N,N-Dimethylaniline (DMA) does initiate the free-radical polymerization of methyl methacrylate (MMA), methyl acrylate, and methyl vinyl ketone. The overall rates of polymerization of MMA were obtained at 40, 50, and 60°C. From the results of a detailed kinetic investigation, the activation enthalpy and activation entropy of polymerization were calculated as 63,2 kJ mol−1 and −153 J mol−1 K−1 at 60°C. Rate equation was also obtained as Rp = k[DMA]1/2[MMA]3/2 and the polymerization was inhibited by benzoquinone. Though styrene alone was not polymerized by DMA, the copolymerization of MMA with styrene by DMA (reactivity ratios: rMMA=0,45 and rSt=0,50) followed a typical free-radical mechanism. An electron-transfer complex between DMA and MMA is proposed as the initiation species.

Plastic deformation of aluminium alloy under abruptly-changing loading or strain paths

Abstract: The effect of deformation history on the plastic behaviour of thin-walled tubular specimens of aluminium alloy 5056 was examined for three types of abruptly-changing loading or strain paths: namely, reverse loading after pre-loading, orthogonal straining after pre-strain, and orthogonal reloading after pre-loading and then perfect unloading, by applying combined loadings of axial force and torque. The experimental results revealed the following trends. The relation between the magnitudes of stress and strain after the comer is expressed for every pre-strain by a single curve parallel to the extension of the pre-loading curve, when the strain after the corner exceeds 1.2 per cent. Moreover, the relations between the stress reduced by pre-stress and strain after the corner for various values of the same type of pre-strain agree with each other; however, the relation for the tensile pre-strain differs clearly from that for the torsional pre-strain. Thus, A.A. Il'yushin's postulate of isotropy does not hold accurately for the above loading histories for the aluminium alloy even if the effect of the third invariant of stress deviator is eliminated.

Water and water vapor permeation and solute separation through poly(n-alkyl L-glutamate) membranes

Abstract: To elucidate the mechanism of water permeation, permeation of water and water vapor through a series of poly(n-alkyl L-glutamates). polymers of methyl, propyl, and butyl glutamate were studied. It was confirmed that water and water vapor permeability were almost one order higher than in cellulose acetate membrane and increased with increasing length of the side chain. The activation energies of the hydraulic permeability of water and the diffusion coefficient of water vapor are almost three times those for pure viscous flow of water. The behavior is analyzed by the free-volume concept for mass transport, and the result shows that the mechanism of water permeation involves the molecular transport of clusters of several water molecules, though the size of the cluster is extremely small compared with that in bulk viscous flow. Separation of water-soluble solute through the homogeneous polypeptide membrane was examined. Though the rejection of NaCl is not as good as in cellulose acetate membranes, th...

Construction of a solution of a certain evolution equation

Abstract: Let us consider the stochastic differential equation, with initial condition, where B t , t ≧ 0, is a one-dimensional Brownian motion, and L x is a second order uniformly elliptic partial differential operator satisfying some additional conditions that will be described in §2. The existence and the uniqueness of solutions of the Cauchy problem have been established by B. L. Rozovskii [8].

Green's function of the clamped punctured disk

Abstract: If a thin elastic circular plate B : ∣ z ∣ z ∣ = 1, its deflection at z ∈ B under a point load at ζ ∈ B , measured positively in the direction of the gravitational pull, is the biharmonic Green's function β( z , ζ) of the clamped plate (γ( z , ζ) of the simply supported plate, respectively). We ask: how do β( z , ζ) and γ( z , ζ) compare with the corresponding deflections β 0 ( z , ζ) and γ 0 ( z , ζ) of the punctured circular plate B 0 : 0 z ∣ z , ζ) is not affected by the puncturing, that is, γ(·, ζ) = γ 0 (·, ζ), whereas β(·, ζ) is: on B 0 × B 0 . Moreover, while β((·, ζ) is of constant sign, β 0 (·, ζ) is not. This gives a simple counterexmple to the conjecture of Hadamard [6] that the deflection of a clampled thin elastic plate be always of constant sign: The biharmonic Gree's function of a clampled concentric circular annulus is not of constant sign if the radius of the inner boundary circle is sufficiently small . Earlier counterexamples to Hadamard's conjecture were given by Duffin [2], Garabedian [4], Loewner [7], and Szego [9]. Interest in the problem was recently revived by the invited address of Duffin [3] before the Annual Meeting of the American Mathematical Society in 1974. The drawback of the counterexample we will present is that, whereas the classical examples are all simply connected, ours is not. In the simplicity of the proof, however, there is no comparison.