This paper presents an element of a 2×2-element array antenna for Inmarsat BGAN/GPS applications. The element is an axial mode printed quadrifilar helical antenna that has been integrated with a compact feed network to provide sequential phase rotation for circular polarization (CP) radiation. The novel integrated lumped-element feed network is designed to provide a balanced RF power to the fou...

In the paper engineering methods for control of distributed parameter systems given by numerical structures on complex shape 3D definition domains are presented. Controlled systems are interpreted as lumped-input/distributed-output systems. Schemes of distributed parameter control loops are arranged. A web-based control design environment from www.dpscontrol.sk will be introduced: Distributed P...

The horn loudspeaker suffers from producing high distortions. Based on an physical model an equivalent lumped parameter circuit is determined for a horn loaded compression driver. From the nonlinear differential equation of this circuit, a compensation algorithm is implemented on a Digital Signal Processor (DSP) for reducing nonlinear distortion caused by the behaviour of air. Test results are ...

The objective of this lecture is to review the basic building blocks of lumped parameter rotational mechanical systems and to build the foundations that will enable you to model more complex dynamic systems consisting of translation and rotational elements. Corresponding to the translational elements mass, spring and damper, are the rotational inertia, rotational spring and rotational damper, r...

This chapter gives an overview of the main physiological applications of collapsible tube flows and reviews the major theoretical and computational developments of the past twenty-five years, ranging from lumped-parameter models to three-dimensional Navier–Stokes simulations. We also discuss some of the significant questions that, despite substantial progress, still remain open. 16 M. HEIL AND ...

Simple, lumped-parameter musculoskeletal models may be more adaptable and practical for clinical real-time control applications, such as prosthesis control. In this study, we determined whether a lumped-parameter, EMG-driven musculoskeletal model with four muscles could predict wrist and metacarpophalangeal (MCP) joint flexion/extension. Forearm EMG signals and joint kinematics were collected s...

The preferred vascular access for hemodialysis is an autologous arteriovenous fistula (AVF) in the arm: a surgically created connection between an artery and vein. The surgeon selects the AVF location based on experience and preoperative diagnostics. However, 20-50% of all lower arm AVFs are hampered by a too low access flow, whereas complications associated with too high flows are observed in ...