摘要:

AbstractThis paper discusses the identification of an asynchronously generated unknown pattern buried in stationary noise. The historical background of the problem is described and it is pointed out that the existence in principle of a solution of this problem is not known. The statistical moment function of the ensemble of observation is defined in the frequency domain and the discussion is carried out in the frequency domain. The pattern is represented in the frequency domain in polar coordinates, and identification is attempted separately for amplitude and phase. The unknown pattern is shown to be identified by utilizing information on the first and the second moment functions of the samples. It is shown that the amplitude term of the solution can be represented quite simply for white noise. It is further shown (even when the noise is not white but is normally distributed) that the amplitude term of the solution can be represented relatively simply by using the third‐order moment function of the sample. It is shown that the phase term of the solution is given as a solution of a certain system of equations. When the characteristic function of the probability density of the fluctuation in position of the pattern is a positive real function, the representation becomes simple by using the first‐order moment function of the sam

ISSN:8756-6621    

DOI:10.1002/ecja.4410640102

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

年代:1981

数据来源: WILEY

摘要:

AbstractThere has been some interest in two‐dimensional digital filters (2D‐DF) which deal with multi‐dimensional information, such as pictures, earthquake waves, etc. If a reversal (recursive) 2D‐DF is composed of adders and resistors in an analog manner, the stability of the system differs from that of the ordinary 2D‐2F without any time element due to minor time delay of adders approximated by linear delay elements. However, if the coefficients of the filter take space‐symmetrical values, stability conditions of both are identical. Hence, the difference has never been noted. We found this fact both experimentally and theoretically and studied each stability condition of the filters for both cases, having infinite and finite constructions. Further, studies were made on mutual relationship between those stability conditions. The 2D‐2F with finite construction treated here is restricted to the case where the size of its lattice is a

ISSN:8756-6621    

DOI:10.1002/ecja.4410640103

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

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper presents a method for the design of linear regulators subject t o minimum performance. This regulator is designed such that it follows the reference model which exhibits desirable transient response. If the quadratic performance function is used for the transient response errors of the control system and the reference model, the optimum solution depends on the in it ial state of the control system. Such initial ‐ state dependency must be eliminated in the design of regulators. A minimax design for the model‐following control system i s described for cases with and without compensators with performance functions, the calculation for obtaining the optimum solution becomes complicated, i. e, it becomes impossible to obtain the minimax solution by directly solving the necessary condition of the optimum solution. This paper proposes a numerical algorithm by which the minimax solution can readily be attai

ISSN:8756-6621    

DOI:10.1002/ecja.4410640104

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

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper proposes a method of analysis of time seriesignals of wave fields by state vectors with regard to complex variablez and discrete time variable. The scalar product of these state vectors, the condition of completeness and operators acting on states are defined and basic equations arqderived. The z‐transformation and the convolution theorem are discussed. The present method is applied to the signal analysis by digital filters wherein the signals in the spatial coordinate of wave fields are converted to the time series signals. Two digital filters are introduced to perform Fresnel transform to express the wave propagation in the Fresnel zone. In this analysis, the filter must have characteristics of propagator transform. Further, amethod of reconstructing images as filter outputs is discussed; the hologram signal is converted to the time s eries signals and input to the filter which performs the Fresnel transformation. The result of image reconstruction by this method is compared with the result obtained by the conventional numerical image reconstruction metho

ISSN:8756-6621    

DOI:10.1002/ecja.4410640105

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn a description of the function of the central nervous system in forearm movement control, the structure of the central nervous system must be considered, together with the control function produced by that structure. In this paper, the motor signal is assumed to originate from the brain, and the forearm movement is defined as the combined cooperative processes (integration) of the reflexes in various portions of the central nervous system, including the brain reflex. Based on this concept, the macroscopic mechanism of the central nervous system is described insofar as this is possible. The forearm movement induced by visual stimulation is then considered, and the response is measured in the frequency domain. A model is constructed for the central functions that describes the frequency response over a relatively wide range and agrees well with the macroscopic mechanism of the central nervous system. This model can be regarded as representing the control‐information processing mechanism and function of the biological system in response to the external environment, reflecting the functions of the higher‐level portion of the central nervous system, i.e., the brain. With the proposed model the behavior can also correspond to the functions and mechanism of the lower levels, i.e., the brainstem‐spinal system, which seems to imply that the brain and brainstem‐spinal systems are similar in functional structure but process different info

ISSN:8756-6621    

DOI:10.1002/ecja.4410640106

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

年代:1981

数据来源: WILEY

摘要:

AbstractAs the objective functions for the placement problems for LSI and printed circuit board, the minimization of the total routing length and the minimization of the maximum min‐cut density have been used. These quantities are considered to reflect the objective of the layout problem (100% wiring ratio) globally. However, since they do not reflect local congestions of wiring, they are often inadequate as an objective function. This paper introduces a new concept of wire‐congestion of segments to represent the degree of local wire congestion. As an objective function, the minimization of the wire conjection of segments is proposed. An efficient heuristic algorithm is developed to minimize this objective function and the results of program experiments are presented to show its effectiveness. As a result of experiments, it was found that the maximum value of the wire‐congestion of segments became smaller as the total routing length became samller and that the former became larger as the latter became larger. Also obtained experimentally was a control parameter (wire‐congestion parameter) which simultaneously makes the total routing length short and the maximum of wire‐congest

ISSN:8756-6621    

DOI:10.1002/ecja.4410640107

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn recent years, the finite element method has been used widely in the field of electrical and electronics engineering. This method is applied mainly to bounded fields with specified boundary conditions. In practice, however, there are many problems dealing with unbounded fields. Several attempts have been made to solve these problems by using free‐space Green's function. Some of them are advantageous in eliminating singularities of Green's function. However, these methods do not produce good calculation result. This paper proposes a new modified finite‐element method which is effective in solving the unbounded electrostatic and electromagnetic‐field problems. This method is applied for the analysis of the field distribution near the open end of the parallel‐plate wa

ISSN:8756-6621    

DOI:10.1002/ecja.4410640108

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

年代:1981

数据来源: WILEY

摘要:

AbstractAn interframe coding system is most promising when a high coding rate is required. However, it is disadvantageous in that the coding rate for the moving picture is not very high. To eliminate this disadvantage, it is effective to compensate for motion displacement. To do this, we propose a method whereby an image is segmented into many blocks. Each block which contains many motion‐displaced pixels compared with that of the previous frame, is selected. A motion vector is considered as a shift vector contained in correlated blocks which is detected by calculating the correlation between the preceding frame and the current frame for each block. A simple application of this idea to interframe coding requires a vast amount of calculation, and the realization of the above real‐time operation device is difficult. This problem is solved by using a system which modifies sequentially the detected motion displacement in the preceding field, and an experimental device for a motion compensated prediction system is built to test its performance. As a result of an experiment on an actual broadcasted moving image, it has been shown that the amount of the active picture elements of the proposed method has been reduced to about 50 ‐ 60% of that of the simple frame‐to‐frame prediction method, and the average log prediction error has been decreased to

ISSN:8756-6621    

DOI:10.1002/ecja.4410640109

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe scattering cross section of the dielectric sphere was expressed in infinite series by Stratton. However, this series is difficult to calculate. In the conventional calculation, the applicable ranges of parameters are limited and the number of terms required for infinite series calculation is not clear. Further, the relation between the resonance of dielectric spheres proposes a new calculation method. The fundamental nature of the resonance of the dielectric sphere is discussed and calculation methods for spherical Bessel functions of complex variables and spherical Hankel functions required for scattering cross‐section calculations are presented. The resonance characteristics of the dielectric sphere are calculated with various parameters and the method of determining the number of terms in the calculation of infinite series is examined. This method is applicable for the calculation of scattering wave from the infinite dielectric cylinde

ISSN:8756-6621    

DOI:10.1002/ecja.4410640110

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

年代:1981

数据来源: WILEY

摘要:

AbstractWhen the parabolic antenna is loaded in its periphery with a choke, the electric current inside the reflector can be suppressed so as to improve the front‐to‐back ratio. This paper establishes the function of the choke and presents qualitatively its effect. A primary radiator used is a shot radiator and the practical antenna is represented by a two‐dimensional model to simplify the treatment in which the function of the choke can be represented by a single integral equation. After solving the integral equation, the choke function and its equivalent magnetic current are obtained, the pattern of the antenna loaded with choke can be calculated from the combined fields due to the magnetic current and the primary radiator, and the results are compared with the measurement. For example, for the case of an antenna 40 cm in diameter loaded by a 3 mm choke at 12 GHz, 5 dB improvement in front‐to‐back ratio can be achieved. Also shown is that the magnetic field component of the slot contributes about 1 dB to t

ISSN:8756-6621    

DOI:10.1002/ecja.4410640111

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

年代:1981

数据来源: WILEY