In this paper, we propose a PWM (Personal Web Map) which is a personal and small database of interesting Web pages to a user, and develop a method to construct it under the user’s control of multiple Web robots. Though general search engine with large databases like YaHoo, AltaVista, MetaCrawler are valid, it is important that a user constructs a small, personal database of relevant Web pages t...

Position weight matrix (PWM) is not only one of the most widely used bioinformatic methods, but also a key component in more advanced computational algorithms (e.g., Gibbs sampler) for characterizing and discovering motifs in nucleotide or amino acid sequences. However, few generally applicable statistical tests are available for evaluating the significance of site patterns, PWM, and PWM scores...

The PWM principle is used to control the output voltage of the three-phase inverters. There are many possible PWM techniques proposed in literature. Among these the space-vector PWM (SVM) method is an advanced PWM method and is possibly the best among all the PWM techniques for variable-frequency drive applications. The classical SVPWM which is used in the direct torque control of induction mot...

A hybrid pulse width modulation (PWM) theme for the grid electrical converter is investigated, which combines the deserves of space-vector PWM (SVM) and elite harmonic elimination PWM (SHEPWM). SHEPWM is adopted at steady state, while SVM is adopted to reach higher dynamic performance at grid fault. A transition strategy between these two PWM schemes is projected, which achieves sleek and fast ...

Pulse with modulation (PWM) is widely used in proportional control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously, the hysteresis can be improved by superimposing dithers with certain frequency and...

LED PWM dimming application for large scale LED video displays is analyzed. The need for short light pulse duration is outlined. PWM dimming with short driving pulses is investigated experimentally. The LED response time skew introduces the nonlinearity for PWM dimming. For LED response time skew estimation, a method is suggested that has been successfully applied to measure some of today’s mar...

In this paper, dynamic overmodulation characteristics of current-regulated carrier-based high-performance pulsewidth modulation (PWM) voltage-source inverter drives are investigated. Dynamic and steady-state overmodulation operating modes are clearly distinguished, and the requirements for obtaining high performance in each mode are shown to be significantly different. Dynamic overmodulation ch...

Abetmct A concept of optimal surplus harmonies distribution in selective harmonic elimination PWM teehnique for multilevel inverters is introduced in this paper. There m e several performance indexes that fan he optimized in PWM inverters, e.g., distortion factor, current or voltage total harmonic distortion, or efficiency. Minimisation of magnetic noise is selected as an example here. Several ...

A novel soft switching PWM converter for high frequency ACIDC andlor DCIAC power conversion is presented by using a new parallel resonant dc-link(PRDCL) and by adopting single phase soft switching(SPSS) technique. The new PRDCL provides variable link pulse position as well as variable link pulse ,width. which is quite different feature from the other resonant dc-links and thus the PWM capabilit...