摘要:

AbstractThis paper considers relationships between structural identifiability of compartmental systems and the interconnections of their compartments. First, structural identifiability is defined in such a way that the definition is practically significant and in addition, the interconnection structure of a system well is represented. Then an algebraic condition equivalent to this definition is derived. Based on this, necessary conditions are derived for classes of compartmental systems to be structurally identifiable in terms of interconnection graphs of compartments. A numerical procedure for examining the structural identifiability is given. The results of the application of this procedure to 3‐ and 4‐compartment systems show that the necessary conditions are also sufficient conditions. Finally, several conjectures based on the results of numerical computations are gi

ISSN:8756-6621    

DOI:10.1002/ecja.4410640302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractAccording to the well‐known sampling theorem, expansion coefficients of a finite Fourier series can be determined from a properly selected finite linear sum of all sampling values which correspond to equally spaced division points in the entire interval of the period. In this paper, the sampling theorem is extended to the case where sampling points under consideration do not necessarily spread out on the entire interval. The first half of this paper considers the case where the sampling point interval is equal to an inverse of integer multiple of the period. The second half considers the more general case and general solutions for the successive extrapolation method are derived in a linear recursive form. This method enables one to calculate frequency components from the waveform which was observed successively at constant pitc

ISSN:8756-6621    

DOI:10.1002/ecja.4410640303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe microwave‐band distributed‐parameter constant‐resistance π‐type circuit composed of multistage two‐wire coupled lines and three resistances can be used as frequency multipliers which generate clock pulses 1010,…, 1–1, 1–1,…. The realization condition is discussed in this paper. The n‐section coupled line is represented by the equivalent signal flow graph where the delay line is considered delay element z−1. The transfer function in the z‐region is expressed by reflection coefficients at each section alone. The frequency‐multiplying circuit presented in this paper is composed of passive elements alone and is free from the external temperature variation. The experimental example is presented to confirm

ISSN:8756-6621    

DOI:10.1002/ecja.4410640304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe surface wave propagation characteristics of several isotropic single‐mode fibers are analyzed by applying the mode‐coupling theorem to left‐handed and right‐handed circularly polarized waves. In the gyrotropic fiber or unidirectional fiber, both polarized waves become eigenmodes and Faraday rotation occurs at linearly polarized wave incidence due to the difference in propagation constants. The rotation angle in the fiber in which the core and clad have the same anisotropy is identical to the rotation angle of a plane wave propagating in infinite gyrotropic media. The 45° Faraday rotator may be constructed by these fibers with sufficiently practica

ISSN:8756-6621    

DOI:10.1002/ecja.4410640305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractAmong those low‐pass band‐limited waveforms which take specified sampled values at a specified finite number of sampling points, the one with minimum energy is called the minimum‐energy waveform. This paper first derives the minimum‐energy waveform and strictly proves its uniqueness. Discussion is then devoted to the minimum‐energy waveform which is determined by sampled values of a low‐pass band‐limited waveform of finite energy, and it is shown that the sequence obtained by successively adding sampling points uniformly converges to a low‐pass band‐limited waveform. In general, when a low‐pass band‐limited waveform is uniquely determined from the sampled values at the sampling points, the sampling point sequence is called complete. This paper shows that various kinds of sampling theorems can be derived, by prescribing sampled values for the low‐pass band‐limited waveform for the complete sampling point sequence given by Levinson and constructing the limiting waveform of minimum energy. Especially, a new reconstruction formula is obtained which restores the original band‐limited waveform solely from the past sampled values. It is shown that the traditional Someya‐Shannon interpolation formula can be obtained by specifying particular sampling points in the above restoration formula. The relation between the t

ISSN:8756-6621    

DOI:10.1002/ecja.4410640306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper considers the restoration problem for images degraded by superposition of normalized white noise, under the assumption that the discrete sampled signal of the image is a two‐dimensional stationary stochastic process, and discusses a new method of restoring images obtained by extending the maximum a posteriori estimation to the two‐dimensional case.The image signal has essentially a two‐dimensional nature and in that sense a comprehensive approach based on a two‐dimensional image model is more suited to the image restoration than recursive processing based on a one‐dimensional image model. From such a viewpoint, this paper first extends the maximum a posteriori estimation to the two‐dimensional case based on the two‐dimensional image model for the purpose of image smoothing. Then, it is shown that the system of equations for the estimation obtained by the proposed estimation method can be represented by a matrix equation, regarding the image as a matrix. It is also shown that the smoothing estimation for the image is obtained as a solution matrix by a simultaneous processing by matrix manipulation. Lastly, computer simulation is presented, indicating the effectiveness of the pr

ISSN:8756-6621    

DOI:10.1002/ecja.4410640307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper is concerned with a new digital processing approach for restoration of additive‐noise‐corrupted images without using a priori statistical information concerning the autocovariance function of the original image field and the variance of noise.Based upon an extended stochastic semi‐causal image model, the method mainly contains two algorithms of image identification and estimation. The algorithm for image identification consists of maximum‐likelihood estimation of unknown parameters and determination of the optimum image model by an information criterion (AIC). Furthermore, recursive Kalman estimation techniques are applied to restore the noise‐corrupt

ISSN:8756-6621    

DOI:10.1002/ecja.4410640308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractWideband operation of a stripline Y‐circulator has been realized below resonance with a coaxially combined two‐layer composite ferrite of nonuniform thickness. The composite ferrite (henceforth referred to as the composite element) consists of a thick ferrite disk with high saturation magnetization and a thin ferrite ring with low saturation magnetization. The circulator consists of tapered striplines and a composite element installed in a stripline Y‐junction and is operated with a uniform applied magnetic field. The insertion loss is less than 0.6 dB and the relative bandwidth is greater than 40% for 20 dB isolation. Circulation takes place at 4–5 different frequencies and is wideband. The paper describes the resonant mode characteristics, the relation between the Y‐junction shape and coupled line width and the structural factor of a composite element of nonuniform

ISSN:8756-6621    

DOI:10.1002/ecja.4410640309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper describes statistical characteristics of the ratios of fading signal envelopes. The Rayleigh fading is contained as a special case. We derive the ratios of the fading signals following the m distribution, generalized Nakagami‐Rice distribution and generalized Nakagami‐Hoyt distribution. An extension to the case of multiple variable distribution is attempted under some conditions. The results in this paper are given in simple functional forms appropriate for theoretical analysis. The distributions of the ratios of fading signal envelopes can be applied to a wide range of problems of radio wave interference such as evaluation of the ratio of desired signal to unwanted interference signal (DU ratio) and of degradation of cross‐polarization discrimination (XPD) in a microwave transmission channel, determination of frequency reuse distance and of modulation types for mobile communications, and analysis of ratio detection in radar techn

ISSN:8756-6621    

DOI:10.1002/ecja.4410640310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractWhen an isotropic optical fiber is twisted, its permittivity becomes anisotropic. In case of a circular fiber, the polarization plane rotates because propagation constants of left‐handed and right‐handed circularly polarized waves are different. In case of an elliptic fiber, the left‐handed and right‐handed circularly polarized waves couple with each other and its polarization characteristics are complicated. The polarization characteristics of the fiber with small twist can be approximated to those of the elliptical fiber and approach those of the circular fiber as the twist angle increases. The effect of the cross‐sectional deformation on the polarization characteristics may be eliminated by applying a large twist on the fiber. The polarization characteristic curves have 90° periodicity with regard to the incident polarization angle. The circularly polarized wave is generated at some incident polarization angle when the ellipticity and twist angle are optimum. These findings coincide with the experiment

ISSN:8756-6621    

DOI:10.1002/ecja.4410640311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY