A polyhedral active set algorithm PASA is developed for solving a nonlinear optimization problem whose feasible set is a polyhedron. Phase one of the algorithm is the gradientprojection method, while phase two is any...
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A polyhedral active set algorithm PASA is developed for solving a nonlinear optimization problem whose feasible set is a polyhedron. Phase one of the algorithm is the gradientprojection method, while phase two is any algorithm for solving a linearly constrained optimization problem. Rules are provided for branching between the two phases. Global convergence to a stationary point is established, while asymptotically PASA performs only phase two when either a nondegeneracy assumption holds, or the active constraints are linearly independent and a strong second-order sufficient optimality condition holds.
In this paper, we propose a new three-user network information flow model, referred to as the triangular multiple-input-multiple-output (MIMO) relay (TMR) channel, which consists of three users and three relays equipp...
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In this paper, we propose a new three-user network information flow model, referred to as the triangular multiple-input-multiple-output (MIMO) relay (TMR) channel, which consists of three users and three relays equipped with n(U) and n(R) antennas, respectively. Each user sends two independent messages to the other two users via the adjacent relays in two time slots, which are referred to as the multiple-access and broadcast stages. We derive a novel simultaneous signal and interference alignment for the proposed TMR channel in a scenario where there are fewer antennas at each relay than at each user (n(R) < n(U)). An optimized pseudo-inverse scheme based on an efficient gradient projection algorithm is proposed to solve the simultaneous alignment problem. By deriving a gradient over weighted sum-rate maximization and applying a gradient descent method, the optimal beamforming vectors are obtained to maximize the effective signal-to-noise ratios. Furthermore, to obtain rapid convergence speed and reduce computational complexity, we introduce a quasi-Newton method, which is referred to as the Broyden-Fletcher-Goldfarb-Shanno algorithm, by approximating the Hessian matrix of a pure Newton method. The convergence of the proposed gradientalgorithm is guaranteed by proposing a line search algorithm. Finally, a performance evaluation shows that the proposed scheme offers a higher sum rate, produces a better outage probability, and achieves a higher multiplexing gain than the existing schemes.
When considering the problem of how to design multi UAV formation keeping optimization model, we combine the kinematic equation of multi UAV, performance index and constrained condition to construct a constrained opti...
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ISBN:
(纸本)9781467374439
When considering the problem of how to design multi UAV formation keeping optimization model, we combine the kinematic equation of multi UAV, performance index and constrained condition to construct a constrained optimization problem. After some transformation is used in the performance function to decompose the optimization problem, we introduce the Lagrange multiplier vector to construct a Lagrange function of this constrained optimization problem. To obtain the two classes of optimization variables-primal variable and dual variable, we find that all primal variables and dual variables can be formulated to the expressions about one dual variable. Then the gradientprojection method from the convex optimization theory is proposed to obtain this dual variable. When this dual variable is solved, all the other optimization variables can also be obtained through simple substitution Finally, the efficiency of the proposed strategy can be confirmed by the simulation results.
We address the carpooling problem as a graph-theoretic problem. If the set of drivers is known in advance, then for any car capacity, the problem is equivalent to the assignment problem in bipartite graphs. Otherwise,...
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We address the carpooling problem as a graph-theoretic problem. If the set of drivers is known in advance, then for any car capacity, the problem is equivalent to the assignment problem in bipartite graphs. Otherwise, when we do not know in advance who will drive their vehicle and who will be a passenger, the problem is NP-hard. We devise and implement quick heuristics for both cases, based on graph algorithms, as well as parallel algorithms based on geometric/algebraic approach. We compare between the algorithms on random graphs, as well as on real, very large, data. (C) 2014 Published by Elsevier B.V.
Reducing the information transmission delay in the Vehicular Ad Hoc Networks(VANETs) can improve the timeliness of receiving information and avoid the happening of the accident. As a potential solution, cooperative tr...
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ISBN:
(纸本)9781479920303
Reducing the information transmission delay in the Vehicular Ad Hoc Networks(VANETs) can improve the timeliness of receiving information and avoid the happening of the accident. As a potential solution, cooperative transmission, which may effectively reduce the transmission delay by exploiting spatial diversity, has attracted lots of attentions recently. In this paper, we modeled the information transmission delay minimization of the VANETs in which cooperative transmission is allowed, and proposed a gradient projection algorithm based on the model. The RSU can schedule the vehicle transmission behavior according to the algorithm, so as to solve the problem of the information transmission delay minimization in the VANETs where multipath routings(MRTDM) are considered. Finally, our simulation results show that the algorithm not only has good convergence, but also can solve the MRTDM in VANETs.
We address the carpooling problem as a graph-theoretic problem. If the set of drivers is known in advance, then for any car capacity, the problem is equivalent to the assignment problem in bipartite graphs. Otherwise,...
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We address the carpooling problem as a graph-theoretic problem. If the set of drivers is known in advance, then for any car capacity, the problem is equivalent to the assignment problem in bipartite graphs. Otherwise, when we do not know in advance who will drive their vehicle and who will be a passenger, the problem is NP-hard. We devise and implement quick heuristics for both cases, based on graph algorithms, as well as parallel algorithms based on geometric/algebraic approach. We compare between the algorithms on random graphs, as well as on real, very large, data.
In this paper, we combine the gradient projection algorithm and the hybrid steepest descent method and prove the strong convergence to a common element of the equilibrium problem;the null space of an inverse strongly ...
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In this paper, we combine the gradient projection algorithm and the hybrid steepest descent method and prove the strong convergence to a common element of the equilibrium problem;the null space of an inverse strongly monotone operator;the set of fixed points of a continuous pseudocontractive mapping and the minimizer of a convex function. This common element is proved to be the unique solution of a variational inequality problem.
Reducing the information transmission delay in the Vehicular Ad Hoc Networks(VANETs) can improve the timeliness of receiving information and avoid the happening of the accident. As a potential solution, cooperative tr...
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Reducing the information transmission delay in the Vehicular Ad Hoc Networks(VANETs) can improve the timeliness of receiving information and avoid the happening of the accident. As a potential solution, cooperative transmission,which may effectively reduce the transmission delay by exploiting spatial diversity, has attracted lots of attentions recently. In this paper, we modeled the information transmission delay minimization of the VANETs in which cooperative transmission is allowed, and proposed a gradient projection algorithm based on the model. The RSU can schedule the vehicle transmission behavior according tothe algorithm, soas tosolve the problem of the information transmission delay minimization in the VANETs where multipath routings(MRTDM) are ***, our simulation results show that the algorithm not only has good convergence, but alsocan solve the MRTDM in VANETs.
We suggest a numerical approximation for an optimization problem, motivated by its applications in finance to find the model-free no-arbitrage bound of variance options given the marginal distributions of the underlyi...
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We suggest a numerical approximation for an optimization problem, motivated by its applications in finance to find the model-free no-arbitrage bound of variance options given the marginal distributions of the underlying asset. A first approximation restricts the computation to a bounded domain. Then we propose a gradient projection algorithm together with the finite difference scheme to solve the optimization problem. We prove the general convergence, and derive some convergence rate estimates. Finally, we give some numerical examples to test the efficiency of the algorithm.
We consider an extension of the Monge-Kantorovitch optimal transportation problem. The mass is transported along a continuous semimartingale, and the cost of transportation depends on the drift and the diffusion coeff...
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We consider an extension of the Monge-Kantorovitch optimal transportation problem. The mass is transported along a continuous semimartingale, and the cost of transportation depends on the drift and the diffusion coefficients of the continuous semimartingale. The optimal transportation problem minimizes the cost among all continuous semimartingales with given initial and terminal distributions. Our first main result is an extension of the Kantorovitch duality to this context. We also suggest a finite-difference scheme combined with the gradient projection algorithm to approximate the dual value. We prove the convergence of the scheme, and we derive a rate of convergence. We finally provide an application in the context of financial mathematics, which originally motivated our extension of the Monge-Kantorovitch problem. Namely, we implement our scheme to approximate no-arbitrage bounds on the prices of exotic options given the implied volatility curve of some maturity.
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