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In this contribution, we examine the development of radio technology before 1921 and the emergence of the broadcasting concept during the World War I. We consider in detail the experiments in the transmitter stations located in Eberswalde and Königs Wusterhausen and numerous sources in order to assess the importance of their work. We also discuss the question of whether the medium of broadcasting ("Rundfunk") started in Germany (or even in Europe) 100 years ago in one of these transmitter stations. [ABSTRACT FROM AUTHOR]

The simulation of large scale nonlinear dynamical interconnected systems, as they arise in all modern engineering disciplines, is a usual task. Due to the high complexity of the considered systems, the principle of thinking in hierarchical structures is essential and common among engineers. Therefore, this contribution proposes an approach for the numerical simulation of large systems, which keeps the hierarchical system structure alive during the entire simulation process while simultaneously exploiting it for order reduction purposes. This is accomplished by embedding the trajectory piecewise linear order reduction scheme in a modified variant of the component connection modeling for building interconnected system structures. The application of this concept is demonstrated by means of a widely used benchmark example and a modified variant of it. [ABSTRACT FROM AUTHOR]

In this contribution, the limitations of the Carleman linearization approach are presented and discussed. The Carleman linearization transforms an ordinary nonlinear differential equation into an infinite system of linear differential equations. In order to transform the nonlinear differential equation, orthogonal polynomials which represent solutions of a Sturm--Liouville problem are used as basis. The determination of the time derivate of this basis yields an infinite dimensional linear system that depends on the considered nonlinear differential equation. The infinite linear system has the same properties as the nonlinear differential equation such as limit cycles or chaotic behavior. In general, the infinite dimensional linear system cannot be solved. Therefore, the infinite dimensional linear system has to be approximated by a finite dimensional linear system. Due to limitation of dimension the solution of the finite dimensional linear system does not represent the global behavior of the nonlinear differential equation. In fact, the accuracy of the approximation depends on the considered nonlinear system and the initial value. The idea of this contribution is to adapt the range of validity for the Carleman linearization in order to increase the accuracy of the approximation for different ranges of initial values. Instead of truncating the infinite dimensional system after a certain order a Taylor series approach is used to approximate the behavior of the nonlinear differential equation about different equilibrium points. Thus, the adapted finite linear system describes the local behavior of the solution of the nonlinear differential equation. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate the use of differential equations by means of an example from network analysis and show that differential/algebraic equations (DAE), rather than explicit ordinary differential equations (ODE), are more suitable for the description of electrical systems and networks. The main ideas of numerical integration of ODEs are presented. We consider this material from the point of view of replacing the ODE by a difference equation (DE). In particular, the relationship between the ODE and the associated DE is discussed. In the last section the application of integration methods for ODEs upon DAEs and its difficulties are discussed. The paper is intended as a review; but a few new results are also included. [ABSTRACT FROM AUTHOR]

Examines algorithms for constructing the Brayton-Moser's mixed potential function for a class of nonlinear reciprocal RLC networks. Construction of Brayton-Moser equations; Existence of the mixed potential function.

Provides a Lagrangian and Hamiltonian formulation for complete nonlinear RLC-networks. Use of the explicit construction of R.K. Brayton and J.K. Moser's mixed potential function; Potentiality for nonequilibrium statistical mechanics.

This paper deals with the propagation of electromagnetic waves in cylindrical waveguides with irregularly deformed cross-sections. The general theory of electromagnetic waves is of high interest because of its practical use as a transmission medium. But only in a few special cases, an analytic solution of Maxwell's equations and the appropriate boundary conditions can be found. The coupled-mode theory, also known as Schelkunoff's method, is a semi-numerical method for computing electromagnetic waves in hollow and cylindrical waveguides bounded by perfect electric walls. It allows to calculate the transverse field pattern and the propagation constant. The aim of this paper is to derive the so-called generalized telegraphist's equations for irregular deformed waveguides. Subsequently, the method's application will be used on a circular waveguide as an illustrating example. [ABSTRACT FROM AUTHOR]

Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov-Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most relevant systems in signal processing applications. The underlying continuous-time systems are transferred to the discrete-time domain using numerical integration methods. Within this contribution, effects on the qualitative behavior of the Andronov-Hopf bifurcation based systems concerning numerical integration methods are analyzed. It is shown exemplarily that explicit Runge-Kutta methods transform the truncated normalform equation of the Andronov-Hopf bifurcation into the normalform equation of the Neimark-Sacker bifurcation. Dependent on the order of the integration method, higher order terms are added during this transformation. A rescaled normalform equation of the Neimark-Sacker bifurcation is introduced that allows a parametric design of a discrete-time system which corresponds to the rescaled Andronov-Hopf system. This system approximates the characteristics of the rescaled Hopf-type amplifier for a large range of parameters. The natural frequency and the peak amplitude are preserved for every set of parameters. The Neimark-Sacker bifurcation based systems avoid large computational effort that would be caused by applying higher order integration methods to the continuous-time normalform equations. [ABSTRACT FROM AUTHOR]

In this contribution, different approaches based on the X-parameters™ to model the behavior of mismatched nonlinear transfer systems are examined. The X-parameters based on the PHD¹-principle introduced by Verspecht and Root (2006) as an extension of the well-known S-parameters describe nonlinear microwave 2-port-networks under large signal conditions. Using load-pull measurement techniques they can be used for arbitrary load situations. Beside this load-pull approach, in the work of Cai et al. (2015), it is stated that it is sufficient to use one optimized X-parameter set for each value of the load reflection coefficient without introducing a large error. In another contribution of Cai and Yu (2015), this approach is extended to cover the whole smith chart with one optimized X-parameter set instead. In this work, these different approaches are compared and brought into question. [ABSTRACT FROM AUTHOR]

In the field of power and drive systems, electrical AC machines are mostly modeled using a set of explicit ordinary differential equations in a state space representation. It is shown, that by using other equation types for simulation, algebraic constraints arising from aggregating several machines to a more complex system can directly be considered. The effects of different model variants on numerical ODE/DAE solvers are investigated in the focus of this work in order perform efficient simulations of larger systems possessing electrical AC machines. [ABSTRACT FROM AUTHOR]

Since the so-called Hopf-type amplifier has become an established element in the modeling of the mammalian hearing organ, it also gets attention in the design of nonlinear amplifiers for technical applications. Due to its pure sinusoidal response to a sinusoidal input signal, the amplifier based on the normal form of the Andronov-Hopf bifurcation is a peculiar exception of nonlinear amplifiers. This feature allows an exact mathematical formulation of the input-output characteristic and thus deeper insights of the nonlinear behavior. Aside from the Hopf-type amplifier we investigate an extension of the Hopf system with focus on ambiguities, especially the separation of solution sets, and double hysteresis behavior in the input-output characteristic. Our results are validated by a DSP implementation. [ABSTRACT FROM AUTHOR]

Recently, nonlinear amplifiers based on the supercritical Andronov--Hopf bifurcation have become a focus of attention, especially in the modeling of the mammalian hearing organ. In general, to gain deeper insights in the inputoutput behavior, the analysis of bifurcation based amplifiers requires a flexible framework to exchange equations and adjust certain parameters. A DSP implementation is presented which is capable to analyze various amplifier systems. Amplifiers based on the Andronov--Hopf and Neimark--Sacker bifurcations are implemented and compared exemplarily. It is shown that the Neimark--Sacker system remarkably outperforms the Andronov--Hopf amplifier regarding the CPU usage. Nevertheless, both show a similar input-output behavior over a wide parameter range. Combined with an USB-based control interface connected to a PC, the digital framework provides a powerful instrument to analyze bifurcation based amplifiers. [ABSTRACT FROM AUTHOR]

SUMMARY This paper presents a discussion of the impact of Büttiker probe scattering on the port behavior of nanoscaled metal-oxide-semiconductor devices. The simulation of the carrier transport property is based on the nonequilibrium Green's function formalisms, and scattering effects are implemented in the model through Büttiker probes. For reducing the computational burden, a simplified model for modeling the scattering effects with only one Büttiker probe is proposed and gives reasonable results for studying the port behaviors of nanoscaled metal-oxide-semiconductor devices. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The "Sonar Hopf" cochlea is a recently much advertised engineering design of an auditory sensor. We analyze this approach based on a recent description by its inventors Hamilton, Tapson, Rapson, Jin, and van Schaik, in which they exhibit the "Sonar Hopf" model, its analysis and the corresponding hardware in detail. We identify problems in the theoretical formulation of the model and critically examine the claimed coherence between the described model, the measurements from the implemented hardware, and biological data. [ABSTRACT FROM AUTHOR]

Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible foil, which supports a metallic pattern, is glued to the surface of the object the torque is being applied to. In case of a deformation due to the torque load, the change in the electrical resistance is measured. With the combination of constitutive equations the applied torque load is determined by the change of electrical resistance. The creep of the glue and the foil material, together with the temperature and humidity dependence, may become an obstacle for some applications (Kapralov and Fesenko, 1984). Thus, there have been optical and magnetical, as well as capacitive sensors introduced (Turner, 1988;Wolffenbuttel and Foerster, 1990). This paper discusses the general idea behind an electrostatic capacitive sensor based on a simple draft of an exemplary measurement setup. For better understanding an own electrostatical, geometrical and mechanical model of this setup has been developed. [ABSTRACT FROM AUTHOR]

In this paper, the series connection of resonant tunneling diodes (RTDs) will be analyzed with respect to their stability properties. An alternative approach to the commonly used loadline construction for the analysis of circuits utilizing the series connection of RTDs is presented. Furthermore, the basins of attraction of multiple operating points will be determined analytically by Brayton-Moser's mixed potential function. Therewith, the jump postulate by Andronov et al. will be generalized for series connected N-type nonlinearities. In addition, the numerical results will be verified by measurements. At the end, the discussed method is applied to the monostable-bistable transition logic element, which today is one of the most promising logic circuits in nanoelectronics. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a stripline model is presented for coupled signal lines routed between a power and a ground plane based on multiconductar transmission line (MTL) theory. Through a suitable diagonalization of the MTL equations for striplines, the transverse electromagnetic (TEM) parallel-plate mode is decoupled from the stripline mode. In this way, stripline models that are obtained assuming ideal planes at ground potential can be extended to take into account the nonideal behavior of the planes. The presented model is applied to represent mode conversion due to vias, holes in the reference planes, and terminations of the stripline. Influence of inhomogeneous media is discussed. [ABSTRACT FROM AUTHOR]