Browsing by Author "Gómez-Pulido, Juan A."
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- Applying Scatter Search to the Location Areas ProblemPublication . Luz, Sónia Maria Almeida da; Vega-Rodríguez, Miguel A.; Gómez-Pulido, Juan A.; Sánchez-Pérez, Juan M.The Location Areas scheme is one of the most common strategies to solve the location management problem, which corresponds to the management of the mobile network configuration with the objective of minimizing the involved costs. This paper presents a new approach that uses a Scatter Search based algorithm applied to the Location Areas scheme as a cost optimization problem. With this work we pretend to analyze and set the main parameters of scatter search, using four distinct test networks and compare our results with those achieved by other authors. This is a new approach to this problem and the results obtained are very encouraging because they show that the proposed technique outperforms the existing methods in the literature.
- Complexity Analysis of HEVC Decoding for Multi-core PlatformsPublication . Cordeiro, Paulo J.; Assunção, Pedro; Gómez-Pulido, Juan A.The High Efficiency Video Coding (HEVC) is the latest standard, providing the same quality as its predecessor H.264/AVC at about half of the bit-rate. An increasing demand for higher quality and better resolutions in mobile applications require the use of more efficient video codecs, but the high computational complexity of HEVC poses problems to resource-constrained devices and portable equipment with limited batery-life. Despite the fact that video coding complexity is much higher than decoding, in most user devices, video decoding is used more often than encoding, thus particular attention must also be given to HEVC decoders. This paper presents an experimental study and complexity analysis of the HEVC decoder’s behaviour when decoding 4k ultra high definition (UHD) and HD video sequences on multi-core platforms, such as those of the most recent mobile devices. It is shown that when tile partitioning is used, different tiles have different decoding complexities. These findings are relevant for devising dynamic tile partitioning schemes capable of achieving load balancing in video decoders running on multi-core platforms.
- Genetic and local search algorithms applied to balanced communication networksPublication . Bernardino, Eugénia; Moreira Bernardino, Anabela; Sánchez-Pérez, Juan M.; Gómez-Pulido, Juan A.; Vega-Rodríguez, Miguel A.In this paper we describe the application of different heuristics to optimise large communication networks. We use Iterated Local Search (ILS), Tabu Search (TS), Simulated Annealing (SA) and Genetic Algorithm (GA) to minimise the link cost to form balanced communication networks. This paper makes a comparison among the effectiveness of ILS, TS, SA and GA on solving large communication networks. Simulation results verify the effectiveness of these algorithms.
- Parameter Analysis for Differential Evolution with Pareto Tournaments in a Multiobjective Frequency Assignment ProblemPublication . Maximiano, Marisa; Vega-Rodríguez, Miguel A.; Gómez-Pulido, Juan A.; Sánchez-Pérez, Juan M.This paper presents a multiobjective approach for the Frequency Assignment Problem (FAP) in a real-world GSM network. Indeed, nowadays in GSM systems, the FAP stills continues to be a critical task for the mobile communication operators. In this work we propose a new method to address the FAP by applying the Differential Evolution (DE) algorithm in its multiobjective optimization, using the concept of Pareto Tournaments (DEPT). We present the results obtained in the tuning process of the DEPT parameters. Two distinct real-world instances of the problem - being currently operating - were tested with DEPT algorithm. Therefore, with this multiobjective approach for the FAP we are contributing to a really important applicability.
- The Radio Network Design Optimization ProblemPublication . Mendes, Silvio; Gómez-Pulido, Juan A.; Vega-Rodríguez, Miguel A.; Sánchez-Pérez, Juan M.; Sáez, Yago; Isasi, PedroThe fast growth and merging of communication infrastructures and services turned the planning and design of wireless networks into a very complex subject. The Radio Network Design (RND) is a NP-hard optimization problem which consists on the maximization of the coverage of a given area while minimizing the base station (BS) deployment. Solving such problems resourcefully is relevant for many fields of application and has direct impact in engineering, scientific and industrial areas. Its significance is growing due to cost dropping or profit increase allowance and can additionally be applied to several different business targets. Numerous works can be found in the literature dealing with the RND problem, although they all suffer from the same shortfall: a non-comparable efficiency. Therefore, the aim of this work is threefold: first, to offer a reliable RND benchmark reference covering a wide algorithmic spectrum, second, to offer a grand insight of accurately comparisons of efficiency, reliability and swiftness of the different employed algorithmic models and third, to disclose reproducibility details of the implemented models, including simulations of a hardware co-processing accelerator.
- Solving a Realistic Location Area Problem Using SUMATRA Networks with the Scatter Search AlgorithmPublication . Luz, Sónia Maria Almeida da; Vega-Rodríguez, Miguel A.; Gómez-Pulido, Juan A.; Sánchez-Pérez, Juan M.This paper presents a new approach based on the Scatter Search (SS) algorithm applied to the Location Management problem using the Location Area (LA) scheme. The LA scheme is used to achieve the best configuration of the network partitioning, into groups of cells (location areas), that minimizes the costs involved. In this work we execute five distinct experiments with the aim of setting the best values for the Scatter Search parameters, using test networks generated with realistic data [1]. We also want to compare the results obtained by this new approach with those achieved through classical strategies, other algorithms from our previous work and also by other authors. The simulation results show that this SS based approach is very encouraging.
- Solving the Ring Loading Problem Using Genetic Algorithms with Intelligent Multiple OperatorsPublication . Bernardino, Anabela M.; Bernardino, Eugénia M.; Sánchez-Pérez, Juan M.; Gómez-Pulido, Juan A.; Vega-Rodríguez, Miguel A.; Moreira Bernardino, Anabela; Bernardino, EugéniaPlanning optical communication networks suggests a number of new optimization problems, most of them in the field of combinatorial optimization. We address here the Ring Loading Problem. The objective of the problem is to find a routing scheme such that the maximum weighted load on the ring is minimized. In this paper we consider two variants: (i) demands can be split into two parts, and then each part is sent in a different direction; (ii) each demand must be entirely routed in either of the two directions, clockwise or counterclockwise. In this paper, we propose a genetic algorithm employing multiple crossover and mutation operators. Two sets of available crossover and mutation operators are established initially. In each generation a crossover method is selected for recombination and a mutation method is selected for mutation based on the amount fitness improvements achieve over a number of previous operations (recombinations/mutations). We use tournament selection for this purpose. Simulation results with the different methods implemented are compared.
- Solving the Terminal Assignment Problem Using a Local Search Genetic AlgorithmPublication . Bernardino, Eugénia M.; Bernardino, Anabela M.; Sánchez-Pérez, Juan M.; Gómez-Pulido, Juan A.; Vega-Rodríguez, Miguel A.; Bernardino, Eugénia; Moreira Bernardino, AnabelaTerminal assignment is an important issue in telecommunication networks optimization. The task here is to assign a given collection of terminals to a given collection of concentrators. The main objective is to minimize the link cost to form a network. This optimization task is an NP-complete problem. The intractability of this problem is a motivation for the pursuits of a local search genetic algorithm that produces approximate, rather than exact, solutions. In this paper, we explore one of the most successful emerging ideas combining local search with population-based search. Simulation results verify the effectiveness of the proposed method. The results show that our algorithm provides good solutions in a better running time.
- Using a hybrid honey bees mating optimisation algorithm for solving SONET/SDH design problemsPublication . Moreira Bernardino, Anabela; Bernardino, Eugénia; Sánchez-Pérez, Juan M.; Gómez-Pulido, Juan A.; Vega-Rodríguez, Miguel A.In this paper we propose a hybrid Honey Bees Mating Optimisation (HBMO) algorithm to solve two problems that arise in the design of optical telecommunication networks known as SONET/SDH Ring Assignment Problem (SRAP) and Intraring Synchronous Optical Network Design Problem (IDP). In SRAP the objective is to minimise the number of rings. In IDP the objective is to minimise the number of Add-Drop Multiplexers (ADMs). Both problems are subject to a ring capacity constraint. HBMO algorithm simulates the mating process of real honey bees. We apply a hybridisation of HBMO to solve these two combinatorial optimisation problems. The feasibility of Hybrid HBMO is demonstrated and compared with the solutions obtained by other algorithms from literature.