<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2006000300011</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[A limit-cycle solver for nonautonomous dynamical systems]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Campos]]></surname>
<given-names><![CDATA[R.G.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Arciniega]]></surname>
<given-names><![CDATA[G.O.]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Michoacana Facultad de Ciencias Físico-Matemáticas ]]></institution>
<addr-line><![CDATA[Mich. Morelia]]></addr-line>
<country>México</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad de Colima Facultad de Ciencias ]]></institution>
<addr-line><![CDATA[Colima Col]]></addr-line>
<country>Méxic</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2006</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2006</year>
</pub-date>
<volume>52</volume>
<numero>3</numero>
<fpage>267</fpage>
<lpage>271</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2006000300011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2006000300011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2006000300011&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[A numerical technique for finding the limit cycles of nonautonomous dynamical systems is presented. This technique uses a matrix representation of the time derivative obtained through the trigonometric interpolation of periodic functions. This differentiation matrix yields exact values for the derivative of a trigonometric polynomial at uniformly spaced points selected as nodes and can therefore be used as the main ingredient of a numerical method for solving nonlinear dynamical systems. We use this technique to obtain some limit cycles and bifurcation points of a sinusoidally driven pendulum and the steady-state response of an electric circuit.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Se presenta una técnica numérica para encontrar los ciclos límite de algunos sistemas dinamicos no autónomos. Esta técnica usa una representación matricial de la derivada temporal obtenida mediante interpolación de funciones periódicas. Produce valores exactos para la derivada de un polinomio trigonometrico en puntos equiespaciados y puede ser usada como elemento principal de un método numérico para resolver sistemas dinámicos no lineales. Usamos esta técnica para obtener algunos ciclos límite y puntos de bifurcación de un péndulo forzado sinusoidalmente y la respuesta estacionaria de un circuito eléctrico.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Nonautonomous dynamical systems]]></kwd>
<kwd lng="en"><![CDATA[nonlinear circuits]]></kwd>
<kwd lng="en"><![CDATA[limit cycles]]></kwd>
<kwd lng="en"><![CDATA[differentiation matrices]]></kwd>
<kwd lng="en"><![CDATA[trigonometric polynomials]]></kwd>
<kwd lng="es"><![CDATA[Sistemas dinámicos no-autónomos]]></kwd>
<kwd lng="es"><![CDATA[circuitos no-lineales]]></kwd>
<kwd lng="es"><![CDATA[ciclos límites]]></kwd>
<kwd lng="es"><![CDATA[matrices de diferenciación]]></kwd>
<kwd lng="es"><![CDATA[polinomios trigonométricos]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="justify"><font face="verdana" size="4">Investigaci&oacute;n</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="4"><b>A limit&#150;cycle solver for nonautonomous dynamical systems</b></font></p>     <p align="center"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="2"><b>R.G. Campos*, G.O. Arciniega**</b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>* Facultad de Ciencias F&iacute;sico&#150;Matem&aacute;ticas, Universidad Michoacana, 58060, Morelia, Mich., M&eacute;xico, e&#150;mail: <a href="mailto:rcampos@umich.mx">rcampos@umich.mx</a></i></font></p>     <p align="justify"><font face="verdana" size="2"><i>** Facultad de Ciencias, Universidad de Colima, 28045, Colima, Col, M&eacute;xico, e&#150;mail: <a href="mailto:gilberto@cgic.ucol.mx">gilberto@cgic.ucol.mx</a></i></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">Recibido el 27 de febrero de 2006    ]]></body>
<body><![CDATA[<br> Aceptado el 6 de abril de 2006</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>     <p align="justify"><font face="verdana" size="2">A numerical technique for finding the limit cycles of nonautonomous dynamical systems is presented. This technique uses a matrix representation of the time derivative obtained through the trigonometric interpolation of periodic functions. This differentiation matrix yields exact values for the derivative of a trigonometric polynomial at uniformly spaced points selected as nodes and can therefore be used as the main ingredient of a numerical method for solving nonlinear dynamical systems. We use this technique to obtain some limit cycles and bifurcation points of a sinusoidally driven pendulum and the steady&#150;state response of an electric circuit.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Keywords: </b>Nonautonomous dynamical systems; nonlinear circuits; limit cycles; differentiation matrices; trigonometric polynomials.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>     <p align="justify"><font face="verdana" size="2">Se presenta una t&eacute;cnica num&eacute;rica para encontrar los ciclos l&iacute;mite de algunos sistemas dinamicos no aut&oacute;nomos. Esta t&eacute;cnica usa una representaci&oacute;n matricial de la derivada temporal obtenida mediante interpolaci&oacute;n de funciones peri&oacute;dicas. Produce valores exactos para la derivada de un polinomio trigonometrico en puntos equiespaciados y puede ser usada como elemento principal de un m&eacute;todo num&eacute;rico para resolver sistemas din&aacute;micos no lineales. Usamos esta t&eacute;cnica para obtener algunos ciclos l&iacute;mite y puntos de bifurcaci&oacute;n de un p&eacute;ndulo forzado sinusoidalmente y la respuesta estacionaria de un circuito el&eacute;ctrico.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Descriptores:</b> Sistemas din&aacute;micos no&#150;aut&oacute;nomos; circuitos no&#150;lineales; ciclos l&iacute;mites; matrices de diferenciaci&oacute;n; polinomios trigonom&eacute;tricos.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">PACS: 05.45.Pq; 02.60.Lj; 02.60.Cb</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v52n3/v52n3a11.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Acknowledgment</b></font></p>     <p align="justify"><font face="verdana" size="2">RGC wishes to thank Dr. A. Medina and Dr. N. Garcia for very useful discussions and suggestions.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>References</b></font></p>     <!-- ref --><p align="justify"><font face="verdana" size="2">1. A.M. Stuart and A.R. Humphries, <i>Dynamical Systems and Numerical Analysis </i>(Cambridge Monographs on Applied and Computational  Mathematics,   Cambridge  University  Press, Cambridge, 1998).</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317891&pid=S0035-001X200600030001100001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">2. T.J. Aprille and T.N. Trick, <i>Proc. IEEE </i><b>60</b> (1972) 108.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317892&pid=S0035-001X200600030001100002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">3. S. Skelboe, <i>IEEE Trans. Circuits Syst. </i><b>CAS&#150;27 </b>(1980) 161.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317893&pid=S0035-001X200600030001100003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">4. R.G. Campos and L.O. Pimentel, <i>J. Comp. Phys. </i><b>160 </b>(2000) 179.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317894&pid=S0035-001X200600030001100004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">5. R.G. Campos and Claudio Meneses, <i>Differentiation matrices for meromorphic functions, </i><a href="http://xxx.lanl.gov/abs/math.NA/0407020" target="_blank">http://xxx.lanl.gov/abs/math.NA/0407020</a> (to be published in <i>Bol. Soc. Mat. Mexicana)</i></font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317895&pid=S0035-001X200600030001100005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">6. R.G. Campos and L.O. Pimentel, <i>Nuovo Cimento B </i><b>116 </b>(2001) 31.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317896&pid=S0035-001X200600030001100006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">7. S.R. Bishop and D.J. Sudor, <i>Int. J. of Bifurcation and Chaos </i><b>9</b> (1999)273.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8317897&pid=S0035-001X200600030001100007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> ]]></body><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stuart]]></surname>
<given-names><![CDATA[A.M.]]></given-names>
</name>
<name>
<surname><![CDATA[Humphries]]></surname>
<given-names><![CDATA[A.R.]]></given-names>
</name>
</person-group>
<source><![CDATA[Dynamical Systems and Numerical Analysis]]></source>
<year>1998</year>
<publisher-loc><![CDATA[Cambridge ]]></publisher-loc>
<publisher-name><![CDATA[Cambridge University Press]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Aprille]]></surname>
<given-names><![CDATA[T.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Trick]]></surname>
<given-names><![CDATA[T.N.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proc. IEEE]]></source>
<year>1972</year>
<volume>60</volume>
<page-range>108</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Skelboe]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[IEEE Trans. Circuits Syst.]]></source>
<year>1980</year>
<volume>CAS-27</volume>
<page-range>161</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Campos]]></surname>
<given-names><![CDATA[R.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Pimentel]]></surname>
<given-names><![CDATA[L.O.]]></given-names>
</name>
</person-group>
<source><![CDATA[J. Comp. Phys.]]></source>
<year>2000</year>
<volume>160</volume>
<page-range>179</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Campos]]></surname>
<given-names><![CDATA[R.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Meneses]]></surname>
<given-names><![CDATA[Claudio]]></given-names>
</name>
</person-group>
<source><![CDATA[Differentiation matrices for meromorphic functions]]></source>
<year></year>
</nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Campos]]></surname>
<given-names><![CDATA[R.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Pimentel]]></surname>
<given-names><![CDATA[L.O.]]></given-names>
</name>
</person-group>
<source><![CDATA[Nuovo Cimento]]></source>
<year>2001</year>
<volume>B 116</volume>
<page-range>31</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bishop]]></surname>
<given-names><![CDATA[S.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Sudor]]></surname>
<given-names><![CDATA[D.J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. of Bifurcation and Chaos]]></source>
<year>1999</year>
<volume>9</volume>
<page-range>273</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
