217 research outputs found
Preface of the “Fourth Symposium on Physical-chemical Gas-dynamics: Non-equilibrium Processes Modeling and Simulation”
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A Discrete Approach for the Inverse Singular Value Problem in Some Quadratic Group
No full textIn this paper the solution of an inverse singular value problem is considered. First the decomposition of a real square matrix A = USigmaV is introduced, where U and V are real square matrices orthogonal with respect to a particular inner product defined through a real diagonal matrix G of order n having all the elements equal to +/-1, and Sigma is a real diagonal matrix with nonnegative elements, called G-singular values. When G is the identity matrix this decomposition is the usual SVD and Sigma is the diagonal matrix of singular values. Given a set {sigma(1),...,sigma(n)} of n real positive numbers we consider the problem to find a real matrix A having them as G-singular values. Neglecting theoretical aspects of the problem, we discuss only an algorithmic issue, trying to apply a Newton type algorithm already considered for the usual inverse singular value problem
Applying Stabilization Techniques to Orthogonal Gradient Flows
No full textThe solution of ordinary differential systems on manifolds
could be treated as differential algebraic equation. In this paper we consider
the solution of orthogonal differential systems deriving from the
application of the gradient flow techniques to minimization problems.
Neglecting the constraints for the solution a differential system is derived.
Hence the problem is modified introducing a stabilization technique
which is a function of the constrain. The advantage of this approach
is that it is possible to apply non conservative numerical methods which
are cheaper. Some numerical examples are shown
Finite element simulation of stress evolution in a frictional contact system
No full textA 3-dimensional finite element algorithm for modeling nonlinear frictional contact behaviours between deformable bodies with the node-to-point contact element strategy has been proposed and applied here to investigate stress evolution processes of a nonlinear frictional contact system. The numerical results of a typical intra-plate fault bend model demonstrate the efficiency and usefulness of this algorithm
Moscow, Germany, and the West from Khrushchev to Gorbachev
No full textThe 1990s promise a new era for Europe and for East-West relations, as the two German states, which epitomized the continent's postwar division, move rapidly toward unification. In this authoritative account of Soviet-German relations during the critical decades leading up to this revolutionary development, Michael J. Sodaro provides a comparative analysis of Soviet and East German foreign policy toward West Germany of unparalleled scope and originality.Sodaro begins his story in 1963, with Nikita Khrushchev's abortive attempt to strengthen Moscow's ties with Bonn after years of cold war hostility. The author traces the events surrounding Brezhnev's double-edged policy of seeking a political accommodation and economic cooperation with West Germany while simultaneously building up the USSR's nuclear and conventional arsenals. He pays particular attention to such watershed developments as the Prague Spring, Brandt's Ostpolitik, the FRG's deployment of new U.S.missiles, and Gorbachev 's decision to accept a "zero-zero" solution to the Euromissile controversy. Sodaro concludes with a detailed reconstruction of the radical changes in Soviet policy brought about by Gorbachev, culminating in the dramatic opening of the Berlin wall at the end of 1989 and the sudden collapse of East German communist rule.Drawing on a vast array of Soviet sources, the author explores the complex of perceptions and rationales underlying Soviet actions. Sodaro identifies competing tendencies in Moscow's thinking on Germany and on relations with the United States and Western Europe. He demonstrates that Soviet policy toward Germany was marked by considerable ambivalence through most of the period under investigation, reflecting internal disagreements and richly differentiated elite attitudes.Sodaro considers East German foreign policy with equal thoroughness, focusing on how the tensions that arose in the Soviet-East German relationship affected Soviet and East German policies toward Bonn.Moscow, Germany, and the West from Khrushchev to Gorbachev will be indispensable to anyone seeking to understand the extraordinary changes now unfolding in Soviet attitudes and Germany's national developmen
Preface of the “Second symposium on physical-chemical gas-dynamics: Non-equilibrium processes modeling and simulation”
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