Phasor measurement units(PMUs)are fundamental tools in the applications of modern power systems,where synchronized phasor estimations are needed.The accuracy and dynamic performance requirements for phasor,frequency,a...Phasor measurement units(PMUs)are fundamental tools in the applications of modern power systems,where synchronized phasor estimations are needed.The accuracy and dynamic performance requirements for phasor,frequency,and rate of change of frequency(ROCOF)estimations are established in the IEEE Std.C37.118.1-2011 along with the IEEE Std.C37.118.1 a-2014,where two PMU performances are suggested:P class filters for applications requiring fast response and M class filters for applications requiring high rejection to aliased signals.In this paper,a methodology to design new phasor estimators that satisfy the P class and M class requirements in PMUs is presented.The proposed methodology is based on finite impulse response filters,brick-wall filters,and complex filter design concepts,where frequency range,time performance,harmonic rejection and out-of-band interference requirements are considered in its design.A comparative analysis using the reference model given by the IEEE Std.C37.118.1 is presented.The results show the effectiveness of the phasor estimators under steady-state and dynamic conditions according to the PMU standard,making them suitable tools for applications in power systems.展开更多
In this paper, we continue studying the so called best m-term one-sided approximation and Greedy-liked one-sided ap- proximation by the trigonometric polynomials. The asymptotic estimations of the best m-terms one-sid...In this paper, we continue studying the so called best m-term one-sided approximation and Greedy-liked one-sided ap- proximation by the trigonometric polynomials. The asymptotic estimations of the best m-terms one-sided approximation by the trigonometric polynomials on some classes of Besov spaces in the metricLp(Td(1≤p≤∞ are given.展开更多
Objective:To determine the occurrence of class A and class Cβ-Iactamase genes and their cooccurrence in Indian Enterobacteriaceae.Methods:52 third generation cephalosporin resistant isolates were phenotypically detec...Objective:To determine the occurrence of class A and class Cβ-Iactamase genes and their cooccurrence in Indian Enterobacteriaceae.Methods:52 third generation cephalosporin resistant isolates were phenotypically detected by combination disk method and screened by PCR to identify class A and class C typeβ-lactamase genes.Results:Of the 52 isolates,94.2%（49） were found harboring any of the bla<sub>?</sub>,bla<sub>CTX-M</sub>,bla<sub>SHV</sub> and bla<sub>TEM</sub> were present in 82.6%（43/52）, 59.6%（31/52）,and 42.3%（22/52） isolates,respectively.Of the 49 ESBL positive isolates 57.1% （28/49） showed co-occurrence of bla<sub>ampC</sub>with bla<sub>?</sub>.On the contrary,the collection from 2009 showed their co-occurrence in 81.4%isolates.Conclusions:The comparative study shows a downward trend for co-existence of bla<sub>?</sub> with bla<sub>ampC</sub> from 2009 to 2010.Further large scale studies are needed to address the co-occurrence of class A and class Cβ-lactamases in India and the resistance trend occurring over a period of time.展开更多
文摘Phasor measurement units(PMUs)are fundamental tools in the applications of modern power systems,where synchronized phasor estimations are needed.The accuracy and dynamic performance requirements for phasor,frequency,and rate of change of frequency(ROCOF)estimations are established in the IEEE Std.C37.118.1-2011 along with the IEEE Std.C37.118.1 a-2014,where two PMU performances are suggested:P class filters for applications requiring fast response and M class filters for applications requiring high rejection to aliased signals.In this paper,a methodology to design new phasor estimators that satisfy the P class and M class requirements in PMUs is presented.The proposed methodology is based on finite impulse response filters,brick-wall filters,and complex filter design concepts,where frequency range,time performance,harmonic rejection and out-of-band interference requirements are considered in its design.A comparative analysis using the reference model given by the IEEE Std.C37.118.1 is presented.The results show the effectiveness of the phasor estimators under steady-state and dynamic conditions according to the PMU standard,making them suitable tools for applications in power systems.
文摘In this paper, we continue studying the so called best m-term one-sided approximation and Greedy-liked one-sided ap- proximation by the trigonometric polynomials. The asymptotic estimations of the best m-terms one-sided approximation by the trigonometric polynomials on some classes of Besov spaces in the metricLp(Td(1≤p≤∞ are given.
基金Partially funded by Department of Science & Technology,Ministry of Science & Technology,Govt.of India under Scientist Project SR/FT/L-111/2006
文摘Objective:To determine the occurrence of class A and class Cβ-Iactamase genes and their cooccurrence in Indian Enterobacteriaceae.Methods:52 third generation cephalosporin resistant isolates were phenotypically detected by combination disk method and screened by PCR to identify class A and class C typeβ-lactamase genes.Results:Of the 52 isolates,94.2%（49） were found harboring any of the bla<sub>?</sub>,bla<sub>CTX-M</sub>,bla<sub>SHV</sub> and bla<sub>TEM</sub> were present in 82.6%（43/52）, 59.6%（31/52）,and 42.3%（22/52） isolates,respectively.Of the 49 ESBL positive isolates 57.1% （28/49） showed co-occurrence of bla<sub>ampC</sub>with bla<sub>?</sub>.On the contrary,the collection from 2009 showed their co-occurrence in 81.4%isolates.Conclusions:The comparative study shows a downward trend for co-existence of bla<sub>?</sub> with bla<sub>ampC</sub> from 2009 to 2010.Further large scale studies are needed to address the co-occurrence of class A and class Cβ-lactamases in India and the resistance trend occurring over a period of time.
