Startseite A semi-analytic method for fractional-order ordinary differential equations: Testing results
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A semi-analytic method for fractional-order ordinary differential equations: Testing results

  • Sergiy Reutskiy EMAIL logo und Zhuo-Jia Fu
Veröffentlicht/Copyright: 9. Februar 2019
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Abstract

The paper presents the testing results of a semi-analytic collocation method, using five benchmark problems published in a paper by Xue and Bai in Fract. Calc. Appl. Anal., Vol. 20, No 5 (2017), pp. 1305–1312, DOI: 10.1515/fca-2017-0068.

5 Appendix

  1. Let us find the Caputo derivative Dtαm], 0 < α ≤ 1 of the discontinuous function

    Ψmt=0,0ttmttmp,tm<t,DtαΨmt=def1Γ1α0tΨm1τtταdτ.

    Using

    Ψm1t=0,0ttmpttmp1,tm<t,

    we get:

    DtαΨmt=def0,0ttm<2,pΓ1αtmtτtmp1tταdτ,tm<t2,pΓ1αtmtτtmp1tταdτ using τ=ζ+tm=pΓ1α0ttmζ+tmtmp1tζtmαdζ=pΓ1α0ttmζp1ttmζαdζ=ttm=spΓ1α0sζp1sζαdζ=pΓ1α0sζp1sζ1α1dζ=pΓ1αΓpΓ1αΓp+1αspα=pΓpΓp+1αspα=Γp+1Γp+1αspα=Γp+1Γp+1αttmpα.

    Here we use the Euler integral:

    0tζp1tζq1dζ=ΓpΓqΓp+qtp+q1.

    Finally, we obtain:

    DtαΨmt=0,0ttm<2,Γp+1Γp+1αttmpα,tm<t2.
  2. Dt2ut=AtutDt0.5ututt2+e2t.

    Let us consider u,v=Dt0.5ut, and w = ut(t) as independent variables,

    Dt2u=Atuvw2+e2t

    Suppose that u0, v0, w0 are given functions of t which are the initial approximations of the corresponding exact values. Then we have the following relations:

    u=u0+(uu0)=u0+δu,v=v0+(vv0)=v0+δv,w=w0+(ww0)=w0+δw.

    Assuming that δu, δv, δw are small values, the equation can be linearized by the following way:

    uv=u0+δuv0+δvv0δu+u0δv+u0v0=v0(uu0)+u0(vv0)+u0v0=v0u+u0vu0v0,w2=w0+δw2w02+2w0δw=w02+2w0(ww0)=2w0ww02.

    As a result, we get the linear equation with respect to u, v, w:

    Dt2u=Atv0u+u0vu0v02w0ww02+e2t,Dt2u=Atv0tu+Atu0tv2w0tw+e2tAtu0tv0tw02t.

    Returning to the old notations, we get the linear equation

    Dt2u=Atv0tu+Atu0tDt0.5u2w0tu1+e2tAtu0tv0tw02t,

    or

    DtνuDt2u=Btu+CtDt0.5u+Etu1+FtDtνu=Btu+CtDtν1u+Etu1+Ft,

    where

    Bt=Atv0t=AtDt0.5u0,Ct=Atu0t,Et=2w0t=2u01t,Ft=e2tAtu0tDt0.5u0u01t2.
  3. Using the quasilinearization procedure, we can write:

    wsvsw0sv0s+sw0s1v0sww0+sw0sv0s1vv0=sw0s1v0sw+sw0sv0s1v+12sw0sv0s.

    So, the right hand side of the equation (65) can be written in the form:

    Avsws+fItAsw0s1v0sw+Asw0sv0s1v+A12sw0sv0s+fIt=Ptw+Rtv+Ft,

    where

    Pt=Asw0s1v0s,Rt=Asw0sv0s1,Ft=A12sw0sv0s+fIt.

Acknowledgements

The work described in this paper was supported by the National Science Fund of China (Grant Nos. 11772119,11572111), the Foundation for Open Project of State Key Laboratory of Structural Analysis for Industrial Equipment (Grant No. GZ1707), the Sino-Ukraine Science and Technology Cooperation Project (Grant No. CU02-18), the Fundamental Research Funds for the Central Universities (Grant No. 2016B06214), Alexander von Humboldt Research Fellowship (ID: 1195938) and Qing Lan Project.

References

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Received: 2017-12-26
Published Online: 2019-02-09
Published in Print: 2018-12-19

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Heruntergeladen am 16.11.2025 von https://www.degruyterbrill.com/document/doi/10.1515/fca-2018-0084/pdf
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