Showing papers by "University of Patras published in 1978"
TL;DR: The high affinity and density of nuclear receptors in adult brain tissue relative to the developing brain and liver, respectively, point to a continued regulatory role of thyroid hormones in brain.
94 citations
TL;DR: This paper considers the problem of identifying the parameters of dynamic systems from input-output records, both lumped-parameter and distributed-parameters systems, deterministic and stochastic, and a feature of the method permits the identification of unknown initial conditions simultaneously with the parameter identification.
Abstract: This paper considers the problem of identifying the parameters of dynamic systems from input-output records Both lumped-parameter and distributed-parameter systems, deterministic and stochastic, are studied The approach adopted is that of expanding the system variables in Walsh series The key point is an operational matrix P which relates the coefficient matrix Г of the Walsh series of a given function with the coefficient matrix of its first derivative Using this operational matrix P one overcomes the necessity to use differentiated data, a fact that usually is avoided either by integration of the data or by using discrete-time models Actually, the original differential input-output model is converted to a linear algebraic (or regression) model convenient for a direct (or a least squares) solution A feature of the method is that it permits the identification of unknown initial conditions simultaneously with the parameter identification The results are first derived for single-input single-output systems and then are extended to multi-input multi-output systems The case of non-constant parameters is treated by assuming polynomial forms Some results are also included concerning the identification of state-space and integral equation models The theory is supported by two examples, which give an idea of how effective the method is expected to be in the real practice
61 citations
TL;DR: S symmetries are used as another — in addition to the average intensity values—global coarse picture parameter subregion characteristic, of a picture that has been regularly decomposed to a dimensionally reduced subset of a data-structure representation.
53 citations
TL;DR: In this paper, the combination of the two-body problem with that of the motion of a charged particle in a magnetic-dipole field (Stormer's problem) is treated.
Abstract: The combination of the two-body problem with that of the motion of a charged particle in a magnetic-dipole field (Stormer's problem) is treated in this article. Thus, in a long series of articles, a first step is taken to study the behavior of a charged particle in a magnetic-binary system. This first step includes a description of a simple model of such a system, the derivation of the equations of motion of the particle in the system, and a discussion on this foundation of the problem.
40 citations
33 citations
TL;DR: The sterility which is associated with male recombination induced by 31.1 MRF was studied genetically and cytologically and it was found that female sterility mainly involves failure of the heterozygous females to lay eggs because their ovaries are atrophic.
Abstract: The sterility which is associated with male recombination induced by 31.1 MRF was studied genetically and cytologically. In all crosses it was found that female sterility mainly involves failure of the heterozygous females to lay eggs because their ovaries are atrophic. Under the optical microscope, the atrophic ovaries were seen to contain only germaria in their ovarioles. It was also found that in some cases 31.1 MRF affects only one of the two ovaries of the same female. This observation suggests that defective development of atrophic ovaries is not due to influences from the rest of the body but should be attributed to the inability of the germ cells to differentiate. Moreover, various stocks as well as homologous chromosomes were found to react differently to 31.1 MRF with respect to female sterility. In their effect on male sterility it was observed that some strains behave as neutral and others as reactive when mated with 31.1/ Cy L 4 males.
24 citations
TL;DR: With the high speed of bipolar technologoy and the flexibility of user-microprogrammability, bit-sliced microprocessors are finding a place in critical applications.
Abstract: With the high speed of bipolar technologoy and the flexibility of user-microprogrammability, bit-sliced microprocessors are finding a place in critical applications.
22 citations
TL;DR: In this article, the main features of the experimental data on Hall effect measurements in amorphous semiconductors reported so far are presented, including the magnitude of the Hall mobility, which was found to be a few times 10−l cm2 V−1 s−1 throughout; the sign anomaly of the hall coefficient, i.e., n-type Hall coefficient but p-type Seeback coefficient.
Abstract: This paper presents the main features of the experimental data on Hall effect measurements in amorphous semiconductors reported so far. More specially, it analyses data on chalcogenide glasses, tetrahedral CdGe x As2 glasses and amorphous germanium, silicon and arsenic. Kolomiets and his group at the Ioffe Institute of Leningrad were the first to study systematically the properties of amorphous semiconductors. Kolomiets and Nazarova (1960) published the first experimental work on the Hall effect in chalcogenide glasses, having examined vitreous materials of the Tl2SeAs2(SeTe)3 system II. Two features of great interest emerged from this work. The first is the magnitude of the Hall mobility, which was found to be a few times 10−l cm2 V−1 s−1 throughout; the second is the sign anomaly of the Hall coefficient, i.e. n-type Hall coefficient but p-type Seeback coefficient. Eighteen years later these features still represent the principal differences between Hall effect results on amorphous, as compared ...
22 citations
21 citations
TL;DR: In this article, the authors present a tensor-based method for dynamic simulation of multiterminal a.c-d.c systems, which uses the generalised loop impedance matrix of the interconnected system from the sub-matrices corresponding to the converter bridges and new states introduced by the passive interconnecting elements.
Abstract: This paper develops a new method for dynamic simulation of multiterminal a.c-d.c. systems. The basic feature of the proposed method is the algorithm that assembles the generalised loop impedance matrix of the interconnected system from the sub-matrices corresponding to the converter bridges and the new states introduced by the passive interconnecting elements. Using the generalised loop impedance matrix and introducing tensor analysis techniques, the differential equations of the system are automatically assembled to deal with the periodically varying topology of the network.
17 citations
TL;DR: A genetically abnormal but structurally normal second chromosome which induces recombination in the male sex, was introduced by outcrossing into the cytoplasm of a normal strain, indicating a gradual acquisition of resistance against the activities of the 31.1 MRF.
Abstract: A genetically abnormal but structurally normal second chromosome (31.1 MRF) which induces recombination in the male sex, was introduced by outcrossing into the cytoplasm of a normal strain. In this new combination, male recombination frequency induced by females dropped from 3.81% to 0.17% within 10 generations, indicating a gradual acquisition of resistance against the activities of the 31.1 MRF.
TL;DR: In this paper, the unsteady flow near an infinite flat plate, which is oscillating harmonically in its own plane, is studied in the presence of a magnetic field subjected to suction or injection.
Abstract: The unsteady flow near an infinite flat plate, which is oscillating harmonically in its own plane, is studied in the presence of a magnetic field subjected to suction or injection. The magnetic field is perpendicular to the plate and the flow of viscous incompressible and electrically conducting fluid is regarded as being initially at rest. Exact solutions for velocity and skin-friction are obtained for the magnetic field fixed to the fluid or to the plate.
01 Jul 1978-International Journal of Human-computer Studies \/ International Journal of Man-machine Studies
TL;DR: The criterion for the selection of the intrasystem control algorithm(s) (code) is based on the maximization of the ‘Joint Figure of Merit’ related to the long-term average of an appropriately weighted sum of conflicting terms: Probabilities of homeostasis versus adequate matching with the partner.
Abstract: The interaction between two self-organizing systems, each possessing two hierarchical levels, is dealt with. The communication process is pursued as a bidirectional information transfer. The criterion for the selection of the intrasystem control algorithm(s) (code) is based on the maximization of the ‘Joint Figure of Merit’ related to the long-term average of an appropriately weighted sum of conflicting terms: Probabilities of homeostasis versus adequate matching with the partner.
TL;DR: In this paper, the six known symmetric simple-periodic oscillations of a charged particle in the meridian plane of an elementary magnetic dipole are presented in a complete form.
Abstract: The six known families of symmetric simple-periodic oscillations of a charged particle in the meridian plane of an elementary magnetic dipole are now presented in a complete form. They begin and terminate by flattening on the equatorial plane of the dipole field. Three new families, consisting of asymmetric periodic oscilltaions, are discovered to branch out of the families of symmetric periodic oscillations of the open-path type.
TL;DR: In this paper, the creation and annihilation operators of the harmonic oscillator in the phase space are considered and the common base of these operators is a generalized Wigner distribution and their coherent states are determined.
Abstract: New creation and annihilation operators of the harmonic oscillator in the phase space are considered. The common base of these operators is a generalized Wigner distribution and their coherent states are determined. Using these operators Weyl's displacement operators and Bopp's translation operators are also determined.
TL;DR: In this paper, the compositional dependence of the Hall mobility in amorphous system As2(S, Se, Te)3 has been investigated and the results are discussed in terms of various models for the Hall effect.
Abstract: Hall effect measurements have been made on vitreous As2Se2.5S0.5, As2SSeTe, and As2SexTe3-x with x = 2.94 and 2.62. Using results from some previous papers (Roilos 1971, Roilos and Mytilineou 1974), it is possible to make a rather detailed survey of the compositional dependence of the Hall mobility in the amorphous system As2(S, Se, Te)3. The Hall mobility decreases by a factor of about two as the As2Te3 content in the As2SexTe3-x glasses is increased from zero up to 40%; it then increases to its initial value at about 75 % As2Te3 and remains roughly constant up to the compound As2Te3. The Hall mobility activation energy shows a similar behaviour, in contrast to the conductivity activation energy which decreases monotonically with increasing As2Te3 content. The results are discussed in terms of various models for the Hall effect in amorphous semiconductors.
TL;DR: The solution leads to a partial knowledge of the input model, which is then completely derived under various constraints on the nature of the model, using a discrete version of Shannon's sampling theorem and the discrete Fourier transform properties.
TL;DR: In this article, the optimal control problem of time-delay systems with partial state measurements is studied through the application of a Walsh function expansion, and the main purpose of the paper is to provide a computational technique for determining the expansion coefficient matrices for both the system state and the observer output.
Abstract: The optimal control problem of time-delay systems with partial state measurements is studied through the application of a, Walsh function expansion. The main purpose of the paper is to provide a computational technique for determining the expansion coefficient matrices for both the system state and the observer output. It is shown that the known initial conditions of the state and the observer can be used iteratively to compute the state and the observer at any subsequent time and thus implement the optimal controller. Also, by subdividing the time interval of interest, the procedure is simplified such that it does not involve any matrix inversion.
TL;DR: In this paper, the efficiency of pinacyanol adsorbed at low surface density on cadmium sulphide was evaluated theoretically for two cases: that of a single molecule adsored at a negatively charged defect, and of a five-member linear-ordered aggregate anchored at a positively charged defect.
Abstract: The efficiency as sensitizer of pinacyanol adsorbed at low surface density on cadmium sulphide is evaluated theoretically for two cases: that of a single molecule adsorbed at a negatively charged defect, and of a five-member linear- ordered aggregate anchored at a negatively charged defect. Ionization energies are calculated by a method based on a set of corrections to the measured ionization energy at high density, and the statistical model is used to estimate efficiency. Both cases show substantial enhancement of effectiveness.
01 Jan 1978
TL;DR: In this article, a general approach to the design/simulation of optimal distributed-parameter controllers and filters based on a combination of Galerkin and Walsh function expansions is presented.
Abstract: The aim of this paper is to present a general approach to the design/simulation of optimal distributed-parameter controllers and filters based on a combination of Galerkin and Walsh function expansions. Firstly, a basic Walsh-Galerkin expansion technique for simulating distributed-parameter systems is developed. Secondly, the formulation and solution of the classical linear quadratic optimal control problem and the optimal minimum variance linear filtering problem are briefly outlined and their duality is established for later use. Thirdly, the Walsh-Galerkin technique is invoked for digitally implementing the optimal controllers and filters derived. Fourthly, the basic Walsh-Galerkin technique is improved by a control-like least squares procedure for better stability and accuracy. Fifthly, the Walsh expansion is used for deriving a direct solution to a class of distributed-parameter variational problems and is applied for designing a generalized quadratic controller of linear distributed-parameter systems in integral form. Finally, illustrative examples are given to support the theory, and appendices are included that provide the basic properties of Walsh functions and an algorithm for overcoming the inversion requirement of the resulting matrices.
TL;DR: In this paper, a general mechanism for surface reactions on a chromatographic column is derived from which the elution curves of the reactant, the products and the peaks produced by stopping the carrier-gas flow for a short time.
TL;DR: In this paper, the properties of an electron moving in one-dimensional periodic potential in the presence of homogeneous mutual perpendicular electric and magnetic fields are discussed, and the perturbation energy is shown, by two different methods, to be a periodic function of the ky quantum number, as required by Harper's conditions.
Abstract: The properties are discussed of an electron moving in one-dimensional periodic potential in the presence of homogeneous mutual perpendicular electric and magnetic fields. The perturbation energy is shown, by two different methods, to be a periodic function of the ky quantum number, as required by Harper's conditions, and also a periodic function of the electric field. Furthermore the partition function is calculated to second order in perturbation. The free energy of the system is evaluated, the magnetic moment as well as the magnetic susceptibility and its dependence on the electric field.
Es werden die Eigenschaften eines sich in einem eindimensionalen periodischen Potential bewegenden Elektrons in homogenen, zueinander senkrechten elektrischen und magnetischen Feldern diskutiert. Es wird mit zwei unterschiedlichen Methoden gezeigt, das die Storungsenergie, wie von der Harperschen Bedingung gefordert, eine periodische Funktion der Quantenzahl ky und ebenso eine periodische Funktion des elektrischen Feldes ist. Daruber hinaus wird die Verteilungsfunktion bis zur zweiten Ordnung der Storung berechnet. Es wird die freie Energie des Systems, das magnetische Moment, die magnetische Suszeptibilitat sowie ihre Abhangigkeit vom elektrischen Feld bestimmt.
TL;DR: In this article, the authors considered four families of plane periodic orbits direct around the Sun which approach Jupiter but they are sufficiently far from it so as to be considered as predominantly two body orbits of the Sun-asteroid system.
Abstract: In this work we consider four families of plane periodic orbits direct around the Sun which approach Jupiter but they are sufficiently far from it so as to be considered as predominantly two body orbits of the Sun-asteroid system. We study their horizontal and vertical stabilities and we give the exact orbits of bifurcations of these families with three-dimensional families of the same multiplicity or twice the multiplicity of the above families of plane symmetric periodic orbits. Moreover, we give the first segments of the three dimensional families of symmetric periodic orbits which emanate from these plane bifurcations and we study their stability relating it with the stability of the plane bifurcations.
TL;DR: In this paper, the synthesis of H-Pro-Leu-β-Ala-NH 2, H-pro-leu-αβ-alanine-α-ala-N(CH 3 ) 2, and H-polygonal polycyclic leu-proline N(CH 2 ) is described.
TL;DR: In this article, a granuliertem Sn with HBr in absolutem Ether gebildete Komplex (II) setzt sich mit Pyridin oder Anilin abhangig vom stochiometrischen Verhaltnis zu den isolierbaren, jedoch instabilen Komplexen (I) bzw.
TL;DR: Results are indicative of a different site of synthesis for the various phosphatases in germinating barley in view of the differences in the site of action of cycloheximide and chloramphenicol.
TL;DR: In this article, an arbitrary (discrete) stochastic process with n-dimensional probability density function was considered and the existence and consistency of the maximum likelihood estimate (MLE) of θ was established.
Abstract: In this paper, we consider an arbitrary (discrete) stochastic process {X
j;j≥1} withn-dimensional probability density function (pdf)
$$f_n \left( {\underset{\raise03em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{x} _n ;\theta } \right) = \prod\limits_{j = 1}^n {f_j \left( {x_j \left| {\underset{\raise03em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{x} _{j - 1} } \right;\theta } \right), \theta \in \Theta \subseteq R^k , k \geqslant 1} $$
We assume the existence and consistency of the maximum likelihood estimate (MLE) of θ, and we establish its asymptotic normality The regularity conditions employed involve the first and second order derivatives of
$$f_j \left( {x_j \left| {\underset{\raise03em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{x} _{j - 1} } \right;\theta } \right)$$
TL;DR: In this paper, the properties of aniline and quinoline with mixed complex haloacids of Indium(III) with thiocyanate are reported.
Abstract: In the present paper the preparation and some properties of compounds of aniline and quinoline with mixed complex haloacids of Indium(III) with thiocyanate are reported. Their UV and IR spectra are discussed.