Influence of nonideal voltage measurement on parameter estimation in permanent-magnet synchronous machines

This paper investigates the influence of nonideal voltage measurements on the parameter estimation of permanentmagnet synchronous machines (PMSMs). The influence of nonideal voltage measurements, such as the dc bus voltage drop, zero shift in the amplifier, and voltage source inverter nonlinearities, on the estimation of different machine parameters is investigated by theoretical and experimental analysis. For analysis, a model-reference-adaptive-system-based estimator is first described for the parameter estimation of the q-axis inductance, stator winding resistance, and rotor flux linkage. The estimator is then applied to a prototype surface-mounted PMSM to investigate the influence of nonideal voltage measurement on the estimation of various machine parameter values. It shows that, at low speed, the inverter nonlinearity compensation has significant influence on both the rotor flux linkage and winding resistance estimations while, at high speed, it has significant influence only on the winding resistance estimation and has negligible influence on the rotor flux linkage estimation. In addition, the inverter nonlinearity compensation will not influence the q-axis inductance estimation when it is under id = 0 control. However, the dc bus voltage drop due to the load variation and zero shift in the amplifier will significantly influence the q-axis inductance estimation. © 2011 IEEE

Online multiparameter estimation of nonsalient-pole PM synchronous machines with temperature variation tracking

The ill-convergence of multiparameter estimation due to the rank-deficient state equations of permanent-magnet synchronous machines (PMSMs) is investigated. It is verified that the PMSM model for multiparameter estimation under id = 0 control is rank deficient for simultaneously estimating winding resistance, rotor flux linkage, and winding inductance and cannot ensure them to converge to the correct parameter values. A new method is proposed based on injecting a short pulse of negative id current and simultaneously solving two sets of simplified PMSM state equations corresponding to id = 0 and id ≠ 0 by using an Adaline neural network. The convergence of solutions is ensured, while the minimum |i d| is determined from the error analysis for nonsalient-pole PMSMs. The proposed method does not need the nominal value of any parameter and only needs to sample the winding terminal currents and voltages, and the rotor speed for simultaneously estimating the dq-axis inductances, the winding resistance, and the rotor flux linkage in nonsalient-pole PMSMs. Compared with existing methods, the proposed method can eliminate the estimation error caused by the variation of rotor flux linkage and inductance as a result of state change due to the injected d-axis current in the surface-mounted PMSM. The method is verified by experiments, and the results show that the proposed method has negligible influence on output torque and rotor speed and has good performance in tracking the variation of PMSM parameters due to temperature variation. © 2010 IEEE

A hypersonic plasma bullet train traveling in an atmospheric dielectric-barrier discharge jet

An experimental observation of fast-moving plasma bullets produced in an atmospheric dielectric-barrier discharge jet is reported in this paper. Nanosecond imaging suggests that the atmospheric discharge jet consists of a plasma bullet train traveling at a hypersonic speed from 7.0 km/s to 43.1 km/s. Yet on a millisecond scale, the bullet train appears as a plasma jet of several centimeters long. The plasma bullets are produced through several possible mechanisms, the most likely of which is related to the ionization wave. Time and space resolved optical emission spectroscopy show that reactive plasma species can be delivered to different spatial sites with varying quantities

Coevolutionary particle swarm optimization using AIS and its application in multiparameter estimation of PMSM

In this paper, a coevolutionary particle-swarm-optimization (PSO) algorithm associating with the artificial immune principle is proposed. In the proposed algorithm, the whole population is divided into two kinds of subpopulations consisting of one elite subpopulation and several normal subpopulations. The best individual of each normal subpopulation will be memorized into the elite subpopulation during the evolution process. A hybrid method, which creates new individuals by using three different operators, is presented to ensure the diversity of all the subpopulations. Furthermore, a simple adaptive wavelet learning operator is utilized for accelerating the convergence speed of the pbest particles. The improved immune-clonal-selection operator is employed for optimizing the elite subpopulation, while the migration scheme is employed for the information exchange between elite subpopulation and normal subpopulations. The performance of the proposed algorithm is verified by testing on a suite of standard benchmark functions, which shows faster convergence and global search ability. Its performance is further evaluated by its application to multiparameter estimation of permanent-magnet synchronous machines, which shows that its performance significantly outperforms existing PSOs. The proposed algorithm can estimate the machine dq-axis inductances, stator winding resistance, and rotor flux linkage simultaneously. © 2013 IEEE

Być dzieckiem we współczesnej Polsce – szkic demograficzny

The binding sites of circLARP4 with miRNAs. a Schematic representation of potential binding sites of miRNAs with circLARP4. b The effects of miR-424 mimic or inhibitor on the expression level of circLARP4 in HCG-27 or MKN-28 cell line indicated by qRT-PCR. c The binding sites of wild type or mutant circLARP4 3’UTR with miR-424.-5p. d qRT-PCR analysis of the expression levels of LATS1 and YAP after transfection with circLARP4 + miR-424 in HGC-27 cells or si-circLARP4 + miR-424 inhibitor in MKN-28 cells. e the luciferase activity of wild type LATS1 3’UTR was examined by co-transfection with miR-424 mimic + circLARP4 in HGC-27 cells. f the luciferase activity of wild type LATS1 3’UTR was detected by co-transfection with miR-424 inhibitor + si-circLARP4 in MKN-28 cells. *P < 0.05; **P < 0.01. (PDF 2681 kb

Current reversals and metastable states in the infinite Bose-Hubbard chain with local particle loss

We present an algorithm which combines the quantum trajectory approach to open quantum systems with a density-matrix renormalization group scheme for infinite one-dimensional lattice systems. We apply this method to investigate the long-time dynamics in the Bose-Hubbard model with local particle loss starting from a Mott-insulating initial state with one boson per site. While the short-time dynamics can be described even quantitatively by an equation of motion (EOM) approach at the mean-field level, many-body interactions lead to unexpected effects at intermediate and long times: local particle currents far away from the dissipative site start to reverse direction ultimately leading to a metastable state with a total particle current pointing away from the lossy site. An alternative EOM approach based on an effective fermion model shows that the reversal of currents can be understood qualitatively by the creation of holon-doublon pairs at the edge of the region of reduced particle density. The doublons are then able to escape while the holes move towards the dissipative site, a process reminiscent---in a loose sense---of Hawking radiation

Integrated saccade latency as a measure of fatigue

INTRODUCTION: High workload, long working hours and inadequate sleep patterns can have deleterious effects on an individual’s performance. Fatigue is often linked with compromised cognitive and motor function. Our information processing system becomes overloaded and unable to monitor and suppress irrelevant information. Subsequent changes in oculomotor parameters and cortical processing times may therefore provide useful biomarkers to assess one’s state of fatigue. We propose a new non-invasive method to quantify fatigue by measuring Eye Movement And Intrinsic Latencies (EMAIL) without the use of any eye-tracking equipment. METHODS: The test is easy to perform and employs a Landolt C flanked by ring distractors. The test is presented at an eccentricity of 8°, randomly on either side of fixation point within ±5° elevation. The measurement variable is the time of presentation, δT. The subject’s task is to saccade to the peripheral target, register the orientation of the gap and respond by pressing one of four buttons. The EMAIL test measures the presentation time, δT, the subject needs to detect the peripheral target, generate an appropriate eye-movement and register the orientation of the gap. RESULTS: The EMAIL test was used to measure the stimulus presentation times needed to achieve 73% correct responses (using a one up, two down staircase). These times were subject specific and ranged from 165 to 200ms in the absence of fatigue. We investigated how, δT, is affected by exposure to other visually demanding tasks and levels of controlled fatigue. Measured integrated oculomotor responses such as latencies and visual processing times were found to increase significantly following demanding visual tasks by as much as 20ms, but only when fatigued. Preliminary findings using the EMAIL test also show that this technique can be used to investigate the effect of stimulants such as caffeine and depressants, such as alcohol. CONCLUSIONS: The EMAIL test provides a simple method to measure oculomotor parameters and to investigate how these are affected by fatigue. This method can be incorporated in the overall safety management system that is often needed in a number of work areas that involve visually-demanding and safety-critical tasks. The measured parameters provide information about an individual’s level of alertness and may also be of relevance in other industries in order to evaluate drugs developed to control fatigue

A Systems Approach to Dissecting Immune Gene Regulatory Networks in the Modulation of Brain Function

Although the central nervous system was long perceived as the ivory tower without immune entities, there is growing evidence that the immune and nervous systems are intimated connected. These two systems have been shown to communicate both cellularly and molecularly under physiological and pathological conditions. Despite our increasing understanding of the interplay between these two systems, there are still numerous open questions. In this thesis, I address such unanswered questions related to: the role of microglia and their mechanism in contributing to pathologies in Rett syndrome; the beneficial effects of T-cell secreted cytokines in supporting social brain function; the evolutionary link of the interactions between the nervous and immune systems; the transcription regulation of a subset of microglia population in common neurodegenerative diseases. Collectively, the current thesis is focused on the joint frontier of bioinformatics and experimental work in neuroimmunology. A multifaceted approach, that includes transcriptomics, genomics and other biomolecular modules, was implemented to unearth signaling pathways and mechanisms underlying the presenting biological phenomena. The findings of this thesis can be summarized as follows: 1) MeCP2 acts as a master regulator in the transcriptional repression of inflammatory stimuli in macrophages; 2) T-cell secreted IFN-γ supports social brain function through an evolutionally conserved interaction between the immune and nervous systems; 3) The APOE-TREM2 pathway regulates the microglia phenotype switch in neurodegenerative diseases. Provided that recent technologies allow for readily manipulating the immune system, the findings presented herein may create new vistas for therapeutic interventions in various neurological disorders

Nuevos datos acerca de los repertorios teatrales en el primer catálogo de «El peregrino en su patria»

En este artículo se muestra cómo los títulos que contienen los repertorios de los autores de comedias presentes en El peregrino en su patria de 1604 están dispuestos según un orden cronológico, aunque con algunos matices y no pocas excepciones. Además, se amplían los repertorios descubiertos por Thornton Wilder y se afina la fecha de composición de varias obras, prestando especial atención a textos que se han perdido, como La perdición de España, La gobernadora, La gran pintora, La bella gitana o La toma de Álora. Finalmente, el presente artículo pretende mostrar de un modo práctico cómo una base de datos digital como el Diccionario biográfico de actores del teatro clásico español (DICAT) puede resultar de gran ayuda a la hora de resolver algunos de los problemas clásicos de la filología en general y del teatro del Siglo de Oro en particular.This paper shows that the plays contained in the repertoire of the autores de comedias which appear in El peregrino en su patria (1604) are organised chronologically, although there are some nuances and exceptions. The article also expands the repertoire discovered by Thornton Wilder and sets the date of composition for some plays, paying special attention to lost texts such as La perdición de España, La gobernadora, La gran pintora, La bella gitana or La toma de Álora. Finally, this paper attempts to show in a practical way that a database such as the Diccionario biográfico de actores del teatro clásico español (DICAT) can be extremely helpful when it comes to dealing with some of the philology's classical problems in general and those of the theatre of the Golden Age in particular

The perception of people with chronic kidney disease towards exercise and physical activity: a literature review

The perception of people with chronic kidney disease towards exercise and physical activity: a literature revie