Abstract: We propose a novel computational implicit method called Isogeometric Residual Minimization (iGRM) with direction splitting. The method mixes the benefits of isogeometric analysis, implicit dynamics, residual minimization, and alternating direction solver. We utilize tensor product B-spline basis functions in space, implicit second-order time integration schemes and residual minimization at every time step. Then, we implement an implicit time integration scheme and apply, for each space-direction, a stabilized mixed method based on residual minimization. Finally, we show that the resulting system of linear equations has a Kronecker product structure, which results in a linear computational cost alternating direction solver, even using implicit time integration schemes together with the stabilized mixed formulation. We test the proposed method on three advection-diffusion computational examples, including model "membrane" problem, the circular wind problem, and the simulations modelling pollution propagating from a chimney.

Abstract: This paper proposes the use of computational methods of Complex Networks Analysis to augment the capabilities of a broker involved in multi agent freight transport negotiation.We have developed an experimentation environment that provides compelling arguments that using our proposed approach the broker is able to apply more effective negotiation strategies for gaining longer term benefits, than those offered by the standard Iterated Contract Net negotiation approach. The proposed negotiation strategies take effect on the entire population of biding agents and are driven by market inspired purposes like for example breaking monopolies and supporting agents with diverse transportation capabilities.

Abstract: We consider the problem of security-aware scheduling and load balancing in Cloud Computing systems. This optimization problem we replace by a game-theoretic approach where players tend to achieve a solution by reaching a Nash equilibrium. We propose a fully distributed algorithm based on applying iterated spatial Prisoner's Dilemma Game and a phenomenon of collective behavior of players participating in the game. Brokers representing users participate in the game to fulfill their own two criteria: the execution time of the submitted tasks and the level of provided security assurance. We experimentally show that in the process of the game a solution is found which provides an optimal resource utilization while users meet their applications’ performance and security requirements with a minimum expenditure and overhead.

Abstract: Most variational forms of isogeometric analysis use highly-continuous basis functions for both trial and test spaces. For a partial differential equation with a smooth solution, isogeometric analysis with highly-continuous basis functions for trial space results in excellent discrete approximations of the solution. However, we observe that high continuity for test spaces is not necessary. In this work, we present a framework which uses highly-continuous B-splines for the trial spaces and basis functions with minimal regularity and possibly lower order polynomials for the test spaces. To realize this goal, we adopt the residual minimization methodology. We pose the problem in a mixed formulation, which results in a system governing both the solution and a Riesz representation of the residual. We present various variational formulations which are variationally-stable and verify their equivalence numerically via numerical tests.