A novel quantum-inspired evolutionary algorithm is proposed based on the Bloch coordinates of quantum bits (qubits) in this paper. The chromosome is comprised of qubits whose Bloch coordinates comprise gene chain. The...
详细信息
A novel quantum-inspired evolutionary algorithm is proposed based on the Bloch coordinates of quantum bits (qubits) in this paper. The chromosome is comprised of qubits whose Bloch coordinates comprise gene chain. The quantum chromosomes are updated by quantum rotation gates, and are mutated by quantum non-gates. For the rotation direction of quantum rotation gates, a simple determining method is proposed. For the rotation and mutation of qubits, two new operators are constructed based on Bloch coordinates of qubits. In this algorithm, the Bloch coordinates of each qubit are regarded as three paratactic genes, each chromosome contains three gene chains, and each gene chain represents an optimization solution, which can accelerate the convergence process for the same number of chromosomes. By two application examples of function extremum and neural network weights optimization, the simulation results show that the approach is superior to common quantum evolutionary algorithm and simple genetic algorithm in both search capability and optimization efficiency. (c) 2007 Elsevier B.V. All rights reserved.
So far most of the K-means algorithms use the number of the labeled data as the K value, but sometimes it doesn't work well. In this paper, we propose a semi-supervised K-means algorithm based on the global optimi...
详细信息
So far most of the K-means algorithms use the number of the labeled data as the K value, but sometimes it doesn't work well. In this paper, we propose a semi-supervised K-means algorithm based on the global optimization. It can select an appropriate number of clusters as the K value directly and plan a great amount of supervision data by using only a small amount of the labeled data. Combining the distribution characteristics of data sets and monitoring information in each cluster after clustering, we use the voting rule to guide the cluster labeling in the data sets. The experiments indicated that the global optimization algorithm for semi-supervised K-means is quite helpful to improve the K-means algorithm, it can effectively find the best data sets for K values and clustering center and enhancing the performance of clustering.
Dynamic resectorization is a promising concept to accommodate the increasing and fluctuating demands of flight operations in the National Airspace System. At the core of dynamic resectorization is finding an optimal s...
详细信息
Dynamic resectorization is a promising concept to accommodate the increasing and fluctuating demands of flight operations in the National Airspace System. At the core of dynamic resectorization is finding an optimal sectorization. Finding such an optimal sectorization is challenging, because it mixes the graph partition problem and non-deterministic polynomial-time-hard optimization problem. This paper revisits Voronoi diagrams and genetic algorithms, and proposes a strategy that combines these algorithms with the iterative-deepening algorithm. Voronoi diagrams accomplish the graph partition, which then needs to be optimized. By defining a multi-objective cost, the combination of the genetic algorithm and iterative deepening algorithm solves the optimization problem. Experimental results show that this method can accomplish sector design by setting an appropriate cost. Without a need of clustering, this method can capture the dominant flow, which is one of the major concerns in sector design. The design can have balanced aircraft count and low coordination. If the capacity is defined and incorporated into the cost, the sectorization will lead to a design with increased capacity. The whole process can be finished within a feasible time period without the need for parallel schemes.
The weapon target assignment problem is about finding the optimal allocation of weapons to threats in a way that minimizes the expected damage inflicted on the defender assets. In 1986 Lloyd and Witsenhousen demonstra...
详细信息
The weapon target assignment problem is about finding the optimal allocation of weapons to threats in a way that minimizes the expected damage inflicted on the defender assets. In 1986 Lloyd and Witsenhousen demonstrated that weapon target assignment was NP-complete with no exact algorithm. Researchers in this area are trying to provide an exact solution to special cases of the problem or heuristics that attempt to supply an approximate solution using a variety of tools and techniques from nonlinear network flows to artificial neural networks and genetic algorithms. A new approach for tackling the weapon target assignment problem is proposed in this paper. Such an approach is a novel goal-based system. The proposed novel approach combines state of the art goal-based optimization approach and the Hungarian method to preserve good performance under different air defense mission configurations. An air defense mission design and analysis package is developed to provide realistic air defense missions data to the algorithm. The proposed algorithm has the best performance when compared with other weapon target assignment doctrines.
This paper demonstrates the significant role that invariant manifolds play in the dynamics of low-thrust trajectories moving through unstable regions in the three-body problem. It shows that an optimization algorithm ...
详细信息
This paper demonstrates the significant role that invariant manifolds play in the dynamics of low-thrust trajectories moving through unstable regions in the three-body problem. It shows that an optimization algorithm incorporating no knowledge of invariant manifolds converges on low-thrust trajectories that use the invariant manifolds of unstable resonant orbits to traverse resonances. It is determined that the algorithm could both change the energy through thrusting to a level where the invariant manifolds could more easily be used, as well as use thrusting to move the trajectory along the invariant manifolds. Knowledge of this relationship has the potential to be very useful in developing initial guesses and new control laws for these optimization algorithms. In particular, this approach can speed up the convergence of the optimization process, retain the essential geometric and topological characteristics of the initial design, and provide a more accurate estimate of the Delta V and fuel usage based on the initial trajectory.
The silicate speciation forms an important aspect of the structure of silicate melts, a subject of interest to both the earth and materials science communities. in this study, the Q(n) speciation of binary cesium sili...
详细信息
The silicate speciation forms an important aspect of the structure of silicate melts, a subject of interest to both the earth and materials science communities. in this study, the Q(n) speciation of binary cesium silicate glasses was studied by Raman spectroscopy. A method to extract the equilibrium constant from a set of Raman spectra is presented, and the least-squares optimization algorithm is given (in Supporting Information). Log(K), the equilibrium constant of the speciation reaction, 2Q(3) = Q(4) + Q(2), equals -2.72 +/- 0.11 at the glass transition. This extends the previously established correlation between log(K) and the inverse of the ionic radius of the network modifier to cesium. Copyright (C) 2009 John Wiley & Sons, Ltd.
The hydrological component of the soil and water assessment tool (SWAT) model is adapted for two Ethiopian catchments based on primary knowledge of the coherence spectrum between rainfall and stream flow data. Spectru...
详细信息
The hydrological component of the soil and water assessment tool (SWAT) model is adapted for two Ethiopian catchments based on primary knowledge of the coherence spectrum between rainfall and stream flow data. Spectrum analysis using the available nearby climatic data is trade to limit the temporal and spatial scales (inverse rate coefficients) subject to the calibration of compartmentalized runoff models. The exclusion of unwarranted time scales in the calibration implies that the model efficiency (r(2) values) decrease only moderately between calibration and validation, and the optimization is focused on warranted problems. On the basis of the available data for the two Ethiopian catchments, the implication is that only periods longer than about 50 days can be reliably evaluated in the model. The model structure of SWAT for the surface runoff and groundwater flow response is modified to make the time scales consistent with the results of the spectrum analysis. An optimization algorithm is developed to constrain and combine the model parameters with the spectrum analysis results. Copyright (C) 2009 John Wiley & Sons, Ltd.
The focus of this paper is an optimal design of morphing aircraft wings employing a wing structure composed of an internal layout of cables and struts. Cables are used to provide actuation and stiffness, and struts pr...
详细信息
The focus of this paper is an optimal design of morphing aircraft wings employing a wing structure composed of an internal layout of cables and struts. Cables are used to provide actuation and stiffness, and struts provide stiffness without actuation. Topology optimization is used to place cables and struts in a bay or a section of the wing. Nonlinear finite element analysis is used to capture the large deformations of the structure, and the optimization is achieved using the Nondominated Sorting Genetic algorithm II. The optimization procedure is illustrated using a morphing wing example. The effect of the upper limit on actuation forces is studied, and solutions are found with good agreement between the desired and obtained deflections under actuation and aerodynamic loads. The implemented parallelized optimization algorithm is successful in solving a computationally intense, multi-objective, multiconstraint problem with a large number of discrete and continuous design variables in a reasonable amount of time.
A new airspace design concept, tube networks, could enable high-density operations with less air traffic control workload. To construct tubes optimally, it is necessary to identify the commonality of flight trajectori...
详细信息
A new airspace design concept, tube networks, could enable high-density operations with less air traffic control workload. To construct tubes optimally, it is necessary to identify the commonality of flight trajectories. This paper proposes a new strategy to cluster great circle flight trajectories for forming tubes. The Hough transform is applied to identify groups or clusters of great circle trajectories that could form the tube networks. The genetic algorithm is then applied to optimize the tube network. Results show that small deviations from great circle routes could yield tubes that accommodate significant traffic levels within feasible computational time.
In this contribution, possibilities and methods for computer-assisted design of ultrasound transducers are described. These transducers are essential for an ultrasonic sensor design, e. g. for continuous non-invasive ...
详细信息
In this contribution, possibilities and methods for computer-assisted design of ultrasound transducers are described. These transducers are essential for an ultrasonic sensor design, e. g. for continuous non-invasive determination of quantities that are important in process technology. To achieve technical reliability and robustness, the precise determination of all acoustic properties of the used sensor materials is of great importance. Problem-oriented modeling, numerical simulation, special optimization algorithms and improved methods for the visualization of propagating waves offer new and promising possibilities for developing ultrasonic transducers with enhanced properties.
暂无评论