During the last five years, several convex optimization algorithms have been proposed for solving inverse problems. Most of the time, they allow us to minimize a criterion composed of two terms one of which permits to...
详细信息
ISBN:
(纸本)9781617388767
During the last five years, several convex optimization algorithms have been proposed for solving inverse problems. Most of the time, they allow us to minimize a criterion composed of two terms one of which permits to "stabilize" the solution. Different choices are possible for the so-called reg-ularization term, which plays a prominent role for solving ill-posed problems. While a total variation regularization introduces staircase effects, a wavelet regularization may bring other kinds of visual artefacts. A compromise can be envisaged combining these regularization functions. In the context of Poisson data, we propose in this paper an algorithm to achieve the minimization of the associated (possibly constrained) convex optimization problem.
Having in mind various implementations of methods for generating network topology [1], [2], [3], there is also a need for a wider mechanism determining receiving nodes in a network by geographical positioning, or one ...
详细信息
Having in mind various implementations of methods for generating network topology [1], [2], [3], there is also a need for a wider mechanism determining receiving nodes in a network by geographical positioning, or one that would be related to link and node parameters. This will allow us to answer the question whether the way receiving nodes are distributed has any influence on the quality of multicast trees constructed by algorithms. The paper proposes methods that arrange group members in packet-switched networks. In the research we discuss the influence of the group arrangement method on the total cost of tree and the average cost of path in a tree for unconstrained routing algorithms for multicast connections. The methods for the receiving nodes distribution in the network have not been hitherto addressed and analyzed in literature.
The paradigm of self-stabilization provides a mechanism to design efficient localized distributed algorithms that are proving to be essential for modern day large networks of sensors. We provide self-stabilizing algor...
详细信息
The paradigm of self-stabilization provides a mechanism to design efficient localized distributed algorithms that are proving to be essential for modern day large networks of sensors. We provide self-stabilizing algorithms (in the shared-variable ID-based model) for three graph optimization problems: a minimal total dominating set (where every node must be adjacent to a node in the set) and its generalizations, a maximal k-packing (a set of nodes where every pair of nodes are more than distance k apart), and a maximal strong matching (a collection of totally disjoint edges).
This paper describes an improved approach in an optimization of different UWB dipole antennas. The new procedure of tuning different optimization algorithms is presented. Fine-tuning of optimizing algorithm which is n...
详细信息
ISBN:
(纸本)9781424447534
This paper describes an improved approach in an optimization of different UWB dipole antennas. The new procedure of tuning different optimization algorithms is presented. Fine-tuning of optimizing algorithm which is not elementary problem is discussed.
Three methods are analyzed for the design of ocean observing systems to monitor the meridional overturning circulation (MOC) in the North Atlantic. Specifically, a continuous monitoring array to monitor the MOC at 100...
详细信息
Three methods are analyzed for the design of ocean observing systems to monitor the meridional overturning circulation (MOC) in the North Atlantic. Specifically, a continuous monitoring array to monitor the MOC at 1000 m at different latitudes is "deployed" into a numerical model. The authors compare array design methods guided by (i) physical intuition (heuristic array design), (ii) sequential optimization, and (iii) global optimization. The global optimization technique can recover the true global solution for the analyzed array design, while gradient-based optimization would be prone to misconverge. Both global optimization and heuristic array design yield considerably improved results over sequential array design. Global optimization always outperforms the heuristic array design in terms of minimizing the root-mean-square error. However, whether the results are physically meaningful is not guaranteed;the apparent success might merely represent a solution in which misfits compensate for each other accidentally. Testing the solution gained from global optimization in an independent dataset can provide crucial information about the solution's robustness.
The analog-integrated circuits industry is exerting increasing pressure to shorten the analog circuit design time. This pressure is put primarily on the analog circuit designers that in turn demand automated circuit d...
详细信息
The analog-integrated circuits industry is exerting increasing pressure to shorten the analog circuit design time. This pressure is put primarily on the analog circuit designers that in turn demand automated circuit design tools evermore vigorously. Such tools already exist in the form of circuit optimization software packages but they all suffer a common ailment - slow convergence. Even taking into account the increasing computational power of modern computers the convergence times of such optimization tools can range from a few days to even weeks. Different authors have tried diverse approaches for speeding up the convergence with varying success. In this paper authors propose a combined optimization algorithm that attempts to improve the speed of convergence by exploiting the positive properties of the underlying optimization methods. The proposed algorithm is tested on a number of test cases and the convergence results are discussed.
We propose a framework for optimization problems based on particle filtering (also called Sequential Monte Carlo method). This framework unifies and provides new insight into randomized optimization algorithms. The fr...
详细信息
ISBN:
(纸本)9781424427086
We propose a framework for optimization problems based on particle filtering (also called Sequential Monte Carlo method). This framework unifies and provides new insight into randomized optimization algorithms. The framework also sheds light on developing new optimization algorithms through die freedom in the framework and the various improving techniques for particle filtering.
Nature inspired optimization algorithm are techniques which imitate some natural phenomenon to rind an optimum solution of a problem. We have explored the potential of three nature inspired continuous optimization tec...
详细信息
ISBN:
(纸本)9781424422104
Nature inspired optimization algorithm are techniques which imitate some natural phenomenon to rind an optimum solution of a problem. We have explored the potential of three nature inspired continuous optimization techniques Simulated Annealing, Genetic algorithms and Particle Swarm optimization in solving the Camera calibration problem in computer vision. Our experiment setup has demonstrated the calibration accuracy achieved with these algorithms with respect to noise levels,variable bounds and number of control points. Results are compared with Tsai, Zhang and Heikkil calibration accuracy. Stochastic nature of these algorithms yields different results for same experiment settings. In order to gain reliable results we have quantitatively determined the probability of achieving accurate results by applying statistical tolerance interval on fitness values computed by each algorithm for various trials. The statistical evaluation shows that in terms of solution accuracy the PSO surpasses SA and GA and produces better results than their non natural competitors Tsai, Zhang and Heikkil, whereas the probability of achieving a correct solution with a desired fitness value range is high with GA. Our work can serve as a guideline for comparative evaluation of natural optimization algorithms with respect to solution quality, reliability and efficiency.
In an assembly line with high labor proportion, the workforce planning and scheduling is a very complex problem. At the background of increasing labor costs, it is very important to increase workforce efficiency. It i...
详细信息
ISBN:
(纸本)9781424427079
In an assembly line with high labor proportion, the workforce planning and scheduling is a very complex problem. At the background of increasing labor costs, it is very important to increase workforce efficiency. It is essential for companies to remain competitive on global markets. Increasing efficiency is our motivation to work on simulation-based workforce scheduling for complex assembly lines. In this paper, we will focus on the heuristic algorithm in our simulation-based optimization approach. The objective is workforce quantity and slack reduction. To improve the objective, an algorithm assigns the number of workers for activities, scheduled in the simulation run. We will present three different strategies implemented in these optimization algorithms. They basically use the performance indicator slack time, work center utilization and a mix of both parameters. We will compare the algorithms according to their achieved objective and the required computation time.
The Business Process Execution Language (BPEL) is now a de facto standard for specifying and executing business process for web service composition and orchestration. As more and more web services are composed using B...
详细信息
ISBN:
(纸本)9783540787884
The Business Process Execution Language (BPEL) is now a de facto standard for specifying and executing business process for web service composition and orchestration. As more and more web services are composed using BPEL, tuning these compositions and gain better performance becomes increasingly important. This paper presents our approach for optimizing the BPEL process and introduces OptBPEL, a tool for performance optimization of BPEL process. The approach starts from the optimization of synchronization structure concerning link in BPEL. After that, some concurrency analysis techniques are applied to obtain further performance improvement. Finally, we give some experiments and prove the efficiency of these optimization algorithms used in OptBPEL.
暂无评论