für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

Operations research specialists at UPS and the Massachusetts Institute of Technology (MIT) created a system to optimize the design of service networks for delivering express packages. The system simultaneously determines aircraft routes, fleet assignments, and package routings to ensure overnight delivery at minimal cost. It has become central to the UPS planning process, fundamentally transfor...

The paper deals with the problem of design and FPGAbased realization of digital circuits with the current-mode gates – novel digital gates operating with constant, continuous power supply current. The purpose is the provision of a high level of noise immunity of chips, which contain both analog and digital circuits. Using proposed approach to design digital current-mode circuits, current-mode p...

Three-phase four-leg inverters are typically employed to supply unbalanced loads avoiding the use of a transformer. Usually, the inverter control is performed by modulation techniques, such as the threedimensional one, requiring complex mathematical algorithms. The paper suggests a different approach, based on the separation of the control of the fourth leg from that of the other phases, allowi...

This paper deals with problems of logical level designing, modelling and simulations of digital, combinatorial circuits, which are based on the current mode gates – new digital elements operating with constant, continuous power supply current. For the modelling and simulation purpose some elements of standard Active – VHDL library IEEE1164 were changed. All designed circuits (one and four bits ...

A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type...

This paper considers the approach to the measurement of internal resistance of the battery in the uninterruptible power sources (UPSs [1]). Advantages of the approach are the measurements in power supplies without switching-off the battery, simplicity in realization of algorithm. The basic expressions of the theory used in the method about internal resistance of the storage battery are consider...