SCIENTIFIC ABSTRACT TIKHONOV, A.N. - TIKHONOV, A.Y.

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CIA-RDP86-00513R001755620001-4
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RIF
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S
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100
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November 2, 2016
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July 16, 2001
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1
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December 31, 1967
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SCIENTIFIC ABSTRACT
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TIKHONOV, A.N.; ENENSHTEYN, B.S. A method for determining the depth of the crystalline bam from the phase curves of electromagnetic frequency soundings. Dokl. AN SSSR .145 no.ls89-92 J1 162. (KIRA 15:7) 1. Hagnitnaya laboratoriya AN SSSR. 2. Chlen-korrespondent AN SSSR (for Tikhonov). (Sounding and soundings) (Geology, Structural) S'/208/63/003/001/004/013 (/0 B112/B1.02 AUTHORS: Tikhgno . A. N.,.Samarskiy, A. A.,,j(moscow) TITLE:, Homogeneous difference schemes with a high degree of accuracy over non-uniform nets . PERIODICAL: Zhurna~ vychislitel-Inoy matematiki i matematiche.9koy fiziki, v. 3, ho. 1, 1963, 99-108 TEXT: This paper is a continuation of previous_~paperse (Zh.vychiaL.mdea.i.. matem. fiz., 1961, 1, No 1, 5-64; and No. 3, 425-440), the fundamental estimates of which are shown to be valid without the additional conditions V 0 M h /h ljh;lo,~ho.. (2) 1N i+1 i\~ M2' The accuracy of zero-rank schemes is characterized.by the mean square step N 1, (1,h2)1/2 Ohi) 1/2. NJ 2 ' 1 ( j!q 2 ). It amounts to 0 : The results of another paper by the same authors Card 1/2 ; 2 S/208/63/003/001/004/013 Homogeneous difference schemes with ... B112/B~102 (~h. vychisl. matem. i matem. fiz., 1962, 2, No- 5, 812-832) concerning the accuracy of standard schemes over non-uniform nets are improved. SUBMITTED: September 29, 1962 Card 2/2 S12081631003100110111013 B112/B102 AUTHORS: Tikhonov, A. N., Gorbunov, A. D. (Mopcow) TITLE: asymptotic estimates of error for a method of the Runge-Xutta ype PERIODICAL: Zhurnal vychislitelonoy matematiki i matematicheskoy fiziki, V. 3, no. 1, 1963, 1'95-197 TEXT: Approximate solutions of the Cauchy problem dy/dx = f(x,y), y(x 0) - Yo (1) by means of a formula of the Runge-Kutta type are considered. It is Bhown that the error satisfies the inequality xk-xo- . ....... O(hG)E- f - exp NLd ~ + 0(h)"111 jjdk 11 1 0 if the function f is continuous and has continuous derivatives of the a-th order. Asymptotic expansions of the error.are derived. SUBIAIT~ED: April 9, 1962 Card 1 1 V,ROXEOV.SIXIY~ Yu.N.;_q ij _kT,OflCvj A. ~ F.L. Burmistro-7; on t-p occasion of his 75th birtnp-i. Zhur. nauch. i prikl. fot- i kin, 8 n0.(".4'75 N-D 16'3. (MrRA 17~1) TIKHONOV, A.N.; SAMARSKIT, A.A. Stability of difference schemes. Dokl.IN SSSR 149 no.33529-531 Mr 163. (MIRA 16:4) 1. Chlen-korrespondent AN SSSR (for Tikhonov). (Difference equations) L 14363-63 Mi (d)/FCC WIMS AFFTC IJP(C) ACCESSION NR: AP3003840 3/002a/63/:L51/003/0501/05o4 AUTHOR: _Tikhono~U A. N. -(Corr. me6. AS, SSSR) TITLE: Solution of incorrectly stated problems and method of regularity - SOURCE: AN SSSR. Doklady*, v. 151, no. 3, 1963, 501-504 TOPIC TAGS: Fredholm equation, ificorrectly stated problem ABSTRACT: An example of an incorrectly stated problem is Fr edhol.1711 sequation of th--- first -kind -where a-solution-is 7 j~equired for the unknown function z(s) given the absolute term u(x).' The paper gives an algorithm for the construction.of a uniform approximation to the function'Pz(s). This algorithm is based on the following principle of regularity: for any a, the lamily za(s) belongs to a compact class containing z(s); u CL(x) tends to u(x) as a tends to zero. The functional Card 1/2 L 14363-63 ACCESSION VR: AP3003840 M'y 1z(s)j tr(x)l NNW, 1M(X)3 + antz(s)] yields the principal results given c>O, there exists a 6>0 such that, corresponding to u*(x), with 1ju*(x) - u(x)11 0 (3) A.Card /2. L 4292-66- ]ACCESSION NRt AP5024202 the unverifiable restriction of independence of the rows of A. He con- istructs an example in which arbitrarily small input changes lead to large output changes (changes of the minimum of Cl which may lead to nonuniqueness). He gives sufficient conditions for uniqueness and proves existence, giving an algorithm for obtaining a solution of (1) stable with respect to small. perturbations of input data A, ill and C# Orig. arto has! 3 formulas, IASSOCIATION: none ~SUBMITTED- 2OApr64 ENCLt 00 SUB CODE: MA :;NO REF.SOVt -004 am, 001 Card '2 TIKHOIMVP A.N. (Moskva) ystems. Stability of algorithms for the sclution of degenerate T of linear algebraic equations. Zhur. vych. mat. I mat. fiz. 5 no.4%718-722 JI-Ag 165. (MIRA 18:8) TIKHONOV, -Akl,,_BAKIlVAIOV, N.S. ........ -- - - , AU-Union Conference on Computer Mathematics. Zhur. -rich. mat, i mat, fiz. 5 no.4:779-780 JI-Ag 165s (MIRA 18;8) L 2283-66 51T(m)/EFF (n) -211WA (h) DY '::ACCESSION NR: AP5016927 UM0089/65/018/006/0588/05931' 621.039-519.22 ~AUTHORS: Tikhonov, A. N.; Arsenin, V. Ya.; Dumova, A. N.; Mayorov i - L. V. ; -r39TU76T',-- 'TITLE: New method of reconstruction of true spectra !SOURCE: Atomnaya energiya, v. 18, no. 6, 1965, 588-593 ITOPIC TAGS, neutron spectrum, neutron energy distribution, nuclear Ireactor ob;racteristic, integral equation, Fredholm equation ABSTRACT: The article presents two examples of the use of a new method of solving problems based on ineomplete experimental data, which arise in the reduction of results of experiments on nuclear re- actors. This method was developed by one of the authors (Tikhonov, DAN SSSR v. 149, 529, 1963) for Fredholm equations of the first kind. The first example considers the reconstruction of the true energy .spectrum of' e2ithermal neutronslin a uranium block of a reactor from ~tbe results of weasuremen with the aid of a mechanical selector. Card 1/2 L 2283-66 ACCESSION NR: AP5016927 IThe second example id devoted to the calculation of the scalar energy !flux. of thermal neutrons In a heterogeneous lattice moderator, from imeasuz,ements of the directional flux. The examples illustrate the )possibility of solving some problems in reactor physics in which the I iexperimentally obtained spectra are distorted because of shortcomings lof the measurement apparatus or of the me thod. Orig. art. has: 4 1 figui4es and 9 formulas IASSOCIATION: None I iSUBMITTED: 15Jun64 ENCL: 00 SUB CODE: NP i jNR REFSOV: 004 OTHER: 003 Card 2/? J') to t AN c'SSR. ACC NR: AT6035242 SOURCE CODE: UR/3043/66/000/005/601M,320 AUTHOR: -ikhonov,.A. N.; Gorbunov, A. D.; Gaysarryan, S. S. . t--' - ORG: none TITLE: Description of an algorithm for optimun mesh construction in solvinZ the Cauchy problem for ordinary differential equations by Runge Kutta methods SOURCE: 'Moscow. Universitet. Vychislitel'nyy tsentr. Sbornik rabot, no. 5, 1966. Vychislitel'nyye metody i programmirovaniye (Computing methods and programming), 17-20 oblem, Runge Ku-6ta TOKC TAGS: Cauchy pr ,,,method, ordinary differential equation, algorithm, differential equation solution ABSTR-kCT: A method is proposed for selecting optimum inhomogeneous meshes when numer,7' ically solving a system of N ordinary differential equations: Y, f (x- Y) Y (xo) = !/0 (Y and fare N-dimensional vectors) in the xo 4 x 4 R segment by a Runge-Kutta method; of degree s. Mesh optimality denotes that at point R the prescribed accuracy c is obtained in the least possible number of steps. An inhomogeneous mesh (network) is given by means of constantX , termed the parameter of the network, and the continuous-~- ly differentiated function ~(x) of the distribution of the network steps so that at any node xi (-(x0, x) integration step hi is determined by Card 1/2 ACC NR: A-16035242 Optimality of the network is achieved by proper selection of netwo'rk7parameterX and kunct ion ~W. The algorithm in question is for the solution of eq. (1) and embodies! a preliminary computation which, although:it does not give y(R) with the necessar, y accuracy, still makes it possible to compute Xand gx), which makes it possible to achieve the required accuracy at point R on the second calculation. The paper gives a method for solving Eq. (1) when N - 1, and adduces two examples of Cauchy problems solved. Orig. art. has: 10 formulas. SUB CODE: 12/.' SUBM DATE: none/ ORIG REF: 001/ OTH REF: 001 2/2 A11C N1, AP6025919 AUTHOR: Tikhonov, A. N. (Moscow) ORG: SOURCE CODE: UR/0208/66/006/004/0631/0634' none TITLE: On stability of the problem of optimizing'functionals SOURCE: Zhurnal vychislitel'noy matematiki i matematic'heskoy fiziki, v. 6, no. 4, 631-634 TOPTC TAGS: function analysis, optimization, mathematic space ABSTRACT: The problem of finding an element which minimizes a given functional has attracted and undoubtedly will continue to attract increasingly greater interest in applied mathematics. Given functional F(z) in some metric space Z, let the problem of minimizing F(z) in Z have a unique solution, i.e., let there be a zo which is the sole element of Z in-which F(z) reaches its minimnm F(zO) = F