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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The VLDB journal 2 (1993), S. 215-241 
    ISSN: 0949-877X
    Keywords: Multidatabases ; replicated data management ; concurrency control ; replica control ; serializability ; resolvable conflicts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Replication is useful in multidatabase systems (MDBSs) because, as in traditional distributed database systems, it increases data availability in the presence of failures and decreases data retrieval costs by reading local or close copies of data. Concurrency control, however, is more difficult in replicated MDBSs than in ordinary distributed database systems. This is the case not only because local concurrency controllers may schedule global transactions inconsistently, but also because local transactions (at different sites) may access the same replicated data. In this article, we propose a decentralized concurrency control protocol for a replicated MDBS. The proposed strategy supports prompt and consistent updates of replicated data by both local and global applications without a central coordinator.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Discrete & computational geometry 9 (1993), S. 351-370 
    ISSN: 1432-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A minimum Steiner tree for a given setX of points is a network interconnecting the points ofX having minimum possible total length. In this note we investigate various properties of minimum Steiner trees in normed planes, i.e., where the “unit disk” is an arbitrary compact convex centrally symmetric domainD having nonempty interior. We show that if the boundary ofD is strictly convex and differentiable, then each edge of a full minimum Steiner tree is in one of three fixed directions. We also investigate the Steiner ratioρ(D) forD, and show that, for anyD, 0.623〈ρ(D)〈0.8686.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica solida Sinica 6 (1993), S. 401-413 
    ISSN: 0894-9166
    Keywords: plate bending problems ; generalized variational principle ; p-version refinement ; biharmonic polynomial space ; finite element method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Two sets of trial functions with different variables are constructed for the admissible space of the finite element analysis. The trial functions satisfy the equilibrium differential equation inside elements, while the deflections and rotations on the edges of the elements are approximated by the Peano hierarchical interpolation functions. Then, a generalized variational principle is applied to set up the p-version hybrid analytical finite element method for plate bending problems. The accuracy of finite element computation can be improved by increasing the order of the interpolation polynomials with fixed mesh. In the finite element formulation, to obtain the stiffness matrices and the load vectors, it is only necessary to perform quadrature over the edges of the elements. These matrices and vectors possess an embedding structure. The conformability between the elements can be controlled automatically.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica solida Sinica 6 (1993), S. 15-26 
    ISSN: 0894-9166
    Keywords: work-hardening ; second-order geometric effects ; shakedown ; discretization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper is based on piecewise linear yield surface and discretization of structure. By allowing for inertial force, damping force and second-order geometric effects, the two generalized dynamic shakedown theorems are given for shakedown analysis of structure.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Numerische Mathematik 64 (1993), S. 85-114 
    ISSN: 0945-3245
    Keywords: 65N30 ; 35J60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We consider efficient finite element algorithms for the computational simulation of type-II superconductors. The algorithms are based on discretizations of a periodic Ginzburg-Landau model. Periodicity is defined with respect to a non-orthogonal lattice that is not necessarily aligned with the coordinate axes; also, the primary dependent variables employed in the model satisfy non-standard “quasi”-periodic boundary conditions. After introducing the model, we define finite element schemes, derive error estimates of optimal order, and present the results of some numerical calculations. For a similar quality of simulation, the resulting algorithms seem to be significantly less costly than are previously used numerical approximation methods.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 25 (1993), S. 467-472 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A novel hybrid surface-emitting laser and two-dimensional laser array is reported. The device consists of rectangular GaAs reflectors and edge-emitting single laser or one-dimensional laser arrays which are fabricated separately. The devices are mounted upside-down on a copper heat sink, allowing for good heat conduction. The CW operation and the reflectivity characteristics of this surface-emitting laser have been investigated.
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  • 7
    ISSN: 1572-8862
    Keywords: Designed synthesis ; heterotrimetallic ; linear complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The complexes [Et4N][(Ph3P)2{M′S2 MS2Fe}Cl2] (M=Mo,M′=Ag;M=W,M′=Cu, Ag) have been obtained by reaction of [Et4N]2[S2 MS2FeCl2] (M=Mo, W) with Cu(PPh3)3Cl or Ag(PPh3)3NO3 in MeCN/CH2Cl2, respectively. Crystal data for [Et4N][(PPh3)2 {AgS2MoS2Fe}Cl2] (I): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.41(1)Å,b=15.54(1)Å,c=12.30(1)Å, α=105.24(6)°, β=94.63(7)°, γ=101.38(6)°, andV=2399(4)Å3. The bond lengths of Mo-Fe bond and the Mo-Ag distance are 2.756(2)Å and 3.033(2)Å, respectively. Crystal data for [Et4N][(PPh3)2 {AgS2WS2Fe}Cl2] (II): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.457(5))Å,b=15.601(6)Å,c=12.338(4)Å, α=105.20(3)°, β=94.61(4)°, γ=101.43(4)°, andV=2426(2)Å3. The bond length of W-Fe bond and the W-Ag distance are 2.786(2)Å and 3.076(1)Å, respectively. Crystal data for [Et4N][(PPh3)2 {CuS2WS2Fe}Cl2] (III): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.498(5)Å,b=15.372(4)Å,c=12.340(4)Å, α=105.54(2)°, β=93.32(3)°, γ=101.40(3)°, andV=2401(1)Å3. The bond lengths of W-Fe bond and the W-Cu bond are 2.800(1)Å and 2.851(1)Å, respectively.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 207 (1993), S. 27-35 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The space correlation of fluctuation of density in the nuclear reaction system inside the stars is investigated by using the theory of a generating function. Referring to the dynamical rate equation, we have introduced the gravitational force and temperature gradient terms into master equation of the probability distribution function of density, and a generalized master equation has been obtained. We take P-PI reactions of hydrogen-burning in the solar core as an example to solve this master equation for infinite medium. A series of waves have been obtained. The first branch is the average density wave which has already been obtained from the dynamical rate equation. Other branches describe the propagation of the fluctuation moments of the local density. They represent the propagation processes of the local distortion of the probability distribution function. Stability of the system may be related to an increase and decay of the waves. We have analysed the phase velocity of these waves.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 209 (1993), S. 221-227 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using Euler's equation of motion, the equation for disturbed fluid motion against a hydrostatic equilibrium has been derived, and the nonequilibrium dynamical equation of a P-PI nuclear reaction system driven by He3 has been analysed using developed nonequilibrium theory. We find that the system in the solar core is unstable in the layer extending from about 0.2R ⊙ to 0.4R ⊙ if the core is disturbed by fluid motion; this instability may be related to thermal diffusion.
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  • 10
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The nonequilibrium dynamical theory of thermonuclear reaction in the stars is used to analyse the stabilities of P-PI reactions in the solar core and 3α reactions of helium burning in the core of red giant stars. The constant stability of stars on the main sequence and the helium “flash” instability have been explained from a new point of view. Calculations show that the (g - T) term in the dynamical equation has a damaging effect on the stability of the thermonuclear reaction, but its intensity in the core of red giant stars is ~ 107 times that in the solar core. It may be intimately related to some instability of the stellar structure. The effect on the “flash” instability is especially analysed.
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