This paper presents the technique to dynamically enhance the power efficiency of PWM class-D amplifier over a wide range of modulation indexes. The power stage of amplifier is segmented into several small stages and selectively enabled according to the power demand (i.e. modulation indexes). The capability of power delivery is dynamically adjusted to minimize the power loss in case of different...

Introduction: Data envelopment analysis (DEA) is a data-oriented method for measuring and benchmarking the relative efficiency of peer decision making units (DMUs) with multiple inputs and multiple outputs. DEA was initiated in 1978 when Charnes, Cooper and Rhodes (CCR) demonstrated how to change a fractional linear measure of efficiency into a linear programming format. This non-parametric app...

To support “Database as a service” (DaaS) in the cloud, the database system is expected to provide similar functionalities as in centralized DBMS such as efficient processing of ad hoc queries. The system must therefore support DBMS-like indexes, possibly a few indexes for each table to provide fast location of data distributed over the network. In such a distributed environment, the indexes ha...

Progress in science and engineering relies on the ability to measure, reliably and in detail, pertinent properties of artifacts under design. Progress in the area of database-index design thus relies on empirical studies based on prototype implementations of indexes. This paper proposes a benchmark that targets techniques for the indexing of the current and near-future positions of moving objec...

Water is one of the most valuable resources for humans. Worldwide, leakage levels in water distribution systems oscillate between 10% and 55%. This causes need constant repairs, economic losses, risk to health users due possible pathogenic intrusion. There are different methods estimating level a network, depending on parameters such as service pressure, orifice size, age pipe material. Sixty-t...