Search results for "Simulated annealing"
showing 10 items of 63 documents
Network analysis by simulated annealing of taxa and islands of Macaronesia (North Atlantic Ocean)
2018
With the aim of explaining the role that taxa and island features have in biogeographical patterns, we processed presence–absence matrices of all the Macaronesian native species of ten different taxa (arthropods, birds, bryophytes, fungi, lichens, mammals, mollusks, pteridophytes, reptiles and spermatophytes) through simulated annealing analysis. Distribution patterns among the archipelagos were pinpointed, along with the different biogeographic roles played by islands and species groups. All the networks analysed resulted to be significantly modular and the structure of biogeographic modules reflects known past connections among the archipelagos and the current drivers of species distribut…
A simulated annealing-based approach for the joint optimization of production/inventory and preventive maintenance policies
2017
Even if more reliable than the past, the performance of modern manufacturing systems is still affected by machine’s deteriorations and breakdowns. As a consequence, adequate maintenance programs must be implemented to adequately satisfy demands during manufacturing stops due to unexpected failures or preventive maintenance (PM) actions. Despite production and maintenance are closely related issues, their joint optimization has become an important research topic just during the last decade. Therefore, the present paper proposes a model for the combined optimization of production/inventory control and PM policies with the aim of minimizing the total expected cost per unit time. The model is f…
SAMSLAM: Simulated Annealing Monocular SLAM
2013
This paper proposes a novel monocular SLAM approach. For a triplet of successive keyframes, the approach inteleaves the registration of the three 3D maps associated to each image pair in the triplet and the refinement of the corresponding poses, by progressively limiting the allowable reprojection error according to a simulated annealing scheme. This approach computes only local overlapping maps of almost constant size, thus avoiding problems of 3D map growth. It does not require global optimization, loop closure and back-correction of the poses.
Neural network prediction in a system for optimizing simulations
2002
Neural networks have been widely used for both prediction and classification. Back-propagation is commonly used for training neural networks, although the limitations associated with this technique are well documented. Global search techniques such as simulated annealing, genetic algorithms and tabu search have also been used for this purpose. The developers of these training methods, however, have focused on accuracy rather than training speed in order to assess the merit of new proposals. While speed is not important in settings where training can be done off-line, the situation changes when the neural network must be trained and used on-line. This is the situation when a neural network i…
Inverse simulated annealing for the determination of amorphous structures
2013
We present a new and efficient optimization method to determine the structure of disordered systems in agreement with available experimental data. Our approach permits the application of accurate electronic structure calculations within the structure optimization. The new technique is demonstrated within density functional theory by the calculation of a model of amorphous carbon.
Domain-Knowledge Optimized Simulated Annealing for Network-on-Chip Application Mapping
2013
Network-on-Chip architectures are scalable on-chip interconnection networks. They replace the inefficient shared buses and are suitable for multicore and manycore systems. This paper presents an Optimized Simulated Annealing (OSA) algorithm for the Network-on-Chip application mapping problem. With OSA, the cores are implicitly and dynamically clustered using knowledge about communication demands. We show that OSA is a more feasible Simulated Annealing approach to NoC application mapping by comparing it with a general Simulated Annealing algorithm and a Branch and Bound algorithm, too. Using real applications we show that OSA is significantly faster than a general Simulated Annealing, withou…
Speeding up of microstructure reconstruction: II. Application to patterns of poly-dispersed islands
2015
We report a fast, efficient and credible statistical reconstruction of any two-phase patterns of islands of miscellaneous shapes and poly-dispersed in sizes. In the proposed multi-scale approach called a weighted doubly-hybrid, two different pairs of hybrid descriptors are used. As the first pair, we employ entropic quantifiers, while correlation functions are the second pair. Their competition allows considering a wider spectrum of morphological features. Instead of a standard random initial configuration, a synthetic one with the same number of islands as that of the target is created by a cellular automaton. This is the key point for speeding-up of microstructure reconstruction, making u…
Statistical Reconstruction of Microstructures Using Entropic Descriptors
2018
We report a multiscale approach of broad applicability to stochastic reconstruction of multiphase materials, including porous ones. The approach devised uses an optimization method, such as the simulated annealing (SA) and the so-called entropic descriptors (EDs). For a binary pattern, they quantify spatial inhomogeneity or statistical complexity at discrete length-scales. The EDs extract dissimilar structural information to that given by two-point correlation functions (CFs). Within the SA, we use an appropriate cost function consisting of EDs or comprised of EDs and CFs. It was found that the stochastic reconstruction is computationally efficient when we begin with a preliminary synthetic…
Packing a trunk - Now with a twist!
2005
In an industry project with a German car manufacturer we are faced with the challenge of placing a maximum number of uniform rigid rectangular boxes in the interior of a car trunk. The problem is of practical importance due to a European industry norm which requires car manufacturers to state the trunk volume according to this measure. No really satisfactory automated solution for this problem has been known in the past. In spite of its NP hardness, combinatorial optimization techniques, which consider only grid-aligned placements, produce solutions which are very close to the one achievable by a human expert in several hours of tedious work. The remaining gap is mostly due to the constrain…
An efficient proposal for the application of simulated annealing algorithms
2014
Complex nonlinear optimization problems require specific resolution techniques. These problems are often characterized by a solution space that presents many local optima. In these cases, local search algorithms, as the classical descent neighborhood search method, have a heavy drawback: the optimization algorithm generally converges towards a local minimum. To avoid getting trapped in a local minimum, the optimization algorithm must allow to accept worse solutions than the current one. Several kinds of algorithms have been ideated for this purpose and they differ for the acceptance criteria of a pejorative solution. Among such algorithms it is possible to remember the Taboo Search (TS) and…