evolutionary algorithms provide reasonable speed in time for solving optimization problems. However, these approaches may stay insufficient when the problem gets bigger and needs more hardware resource. Because it is ...
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ISBN:
(纸本)9781509016792
evolutionary algorithms provide reasonable speed in time for solving optimization problems. However, these approaches may stay insufficient when the problem gets bigger and needs more hardware resource. Because it is not feasible to improve memory and computation power depending on the problem size, there is a need for developing new techniques in order to solve these optimization problems in less time with smaller error ratios. In this study, it is aimed to solve the Traveling Salesman Problem, one of the NP-complete complexity problems, by partitioning the problem with a clustering technique, K-Means, and solving these pieces with Genetic Algorithm and finally combining these solutions into one. As the experimental results suggest, in comparison to solving large scale optimization problems as single problems, solving them by partitioning them yields more convincing results in both solution quality and time. In addition, it is observed that the performance of the technique yields better as the problem size gets bigger.
A number of papers have emerged in the last two years that apply and study asynchronous master-slave evolutionary algorithms based on a steady-state model. These efforts are largely motivated by the observation that, ...
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ISBN:
(纸本)9781450342063
A number of papers have emerged in the last two years that apply and study asynchronous master-slave evolutionary algorithms based on a steady-state model. These efforts are largely motivated by the observation that, unlike traditional (synchronous) EAs, asynchronous EAs are able to make maximal use of many parallel processors, even when some individuals evaluate more slowly than others. Asynchronous EAs do not behave the same as their synchronous counterparts, however, and as of yet there is very little theory that makes it possible to predict how they will perform on new problems. Of some concern is evidence suggesting that the steady-state versions tend to be biased toward regions of the search space where fitness evaluation is cheaper. This has led some authors to suggest a so-called 'quasi-generational' asynchronous EA as an intermediate solution that incurs neither idle time nor significant bias toward fast solutions. We perform experiments with the quasi-generational EA, and show that it does not deliver the promised bene fits: it is, in fact, just as biased toward fast solutions as the steady-state approach is, and it tends to converge even more slowly than the traditional, generational EA.
In parallel to optimizing energy consumption within houses, users' comfort is increasingly considered as an essential success criterion for automated smart home solutions. From the user perspective, balancing trad...
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ISBN:
(纸本)9781509006229
In parallel to optimizing energy consumption within houses, users' comfort is increasingly considered as an essential success criterion for automated smart home solutions. From the user perspective, balancing trade-offs between energy consumption and users' comfort when scheduling home appliances is a challenging task mainly within dynamic context (energy price, budget, user preferences, energy source, etc). To address this challenge, this paper has modeled appliances scheduling as a dynamic constrained multi-objective optimization problem and have leveraged a recently introduced dynamic evolutionary algorithm for the problem resolution. Moreover, there are typically multiple inhabitants in the same home who often share context-aware applications with various individual preferences which are likely to be conflicting. We propose a new comfort function to support multi-user conflictual preferences. Our experimental results have shown that our approach has a confirmed advantage on the user comfort while coping dynamically with the context changes.
The reduction of energy consumption is a major challenge around the world. Architectural aspects have a significant place to minimize energy consumption to the maximum level. The use of large glazed facades causes ove...
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ISBN:
(纸本)9781509006229
The reduction of energy consumption is a major challenge around the world. Architectural aspects have a significant place to minimize energy consumption to the maximum level. The use of large glazed facades causes overheating problems in certain climatic regions. Shading elements must be considered at an early stage in the design process to overcome this problem. An application of the method is presented, focusing on the horizontal louvers integrated to a building in Izmir, Turkey. The contributions of the paper can be summarized as follows. We show that most architectural design problems are basically real-parameter multi-objective constrained optimization problems. So, any type of evolutionary and swarm optimization methods can be used in this field. A multi-objective self-adaptive differential evolution algorithm (jDEMO), inspired from the DEMO algorithm from the literature with some modifications, is developed and compared to the well-known fast and nondominated sorting genetic algorithm so called NSGA-II in order to solve this complex problem and identify alternative design solutions to decision makers. Through the experimental results, we show that the proposed algorithm generated slightly better results when comparing to the NSGA-II algorithm.
Artificial immune systems (AIS) are randomised search heuristics that can be applied to any kind of optimisation problem just like evolutionary algorithms (EAs). Unlike EAs their inception stems from a different natur...
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ISBN:
(纸本)9781450342063
Artificial immune systems (AIS) are randomised search heuristics that can be applied to any kind of optimisation problem just like evolutionary algorithms (EAs). Unlike EAs their inception stems from a different natural paradigm: the immune system of vertebrates instead of natural evolution. While AIS proved to be highly efficient in several application areas, so far for no classic optimisation problem it could be rigorously proven that AIS outperform EAs. We consider the B-Cell Algorithm (BCA) as an example of an artificial immune system and compare its performance with that of the (1+1) EA on a classic combinatorial optimisation problem, interval scheduling. We show that for the natural binary encoding both heuristics are not able to efficiently find an optimal solution for all instances. The (1+1) EA has exponential expected optimisation time and the BCA may never find an optimal solution. However, we also show that a natural preprocessing changes the situation dramatically. If we remove beforehand all intervals strictly containing another one, then the BCA always finds an optimal solution in polynomial expected optimisation time. The (1+1) EA remains inefficient in the worst case, still having exponential expected optimisation time. It can, however, find a 2-approximation of an optimal solution very quickly.
Energy consumption is a matter of paramount importance in nowadays environmentally conscious society. It is also bound to be a crucial issue in light of the emergent computational environments arising from the pervasi...
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ISBN:
(纸本)9783319458236;9783319458229
Energy consumption is a matter of paramount importance in nowadays environmentally conscious society. It is also bound to be a crucial issue in light of the emergent computational environments arising from the pervasive use of networked handheld devices and wearables. evolutionary algorithms (EAs) are ideally suited for this kind of environments due to their intrinsic flexibility and adaptiveness, provided they operate on viable energy terms. In this work we analyze the energy requirements of EAs, and particularly one of their main flavours, genetic programming (GP), on several computational platforms and study the impact that parametrisation has on these requirements, paving the way for a future generation of energy-aware EAs. As experimentally demonstrated, handheld devices and tiny computer models mainly used for educational purposes may be the most energy efficient ones when looking for solutions by means of EAs.
Factored evolutionary algorithms (FEA) have proven to be fast and efficient optimization methods, often outperforming established methods using single populations. One restriction to FEA is that it requires a central ...
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ISBN:
(纸本)9781450342063
Factored evolutionary algorithms (FEA) have proven to be fast and efficient optimization methods, often outperforming established methods using single populations. One restriction to FEA is that it requires a central communication point between all of the factors, making FEA difficult to use in completely distributed settings. The Distributed Factored evolutionary Algorithm (DFEA) relaxes this requirement on central communication by having neighboring factors communicate directly with one another. While DFEA has been effective at finding good solutions, there is often an increase in computational complexity due to the communication between factors. In previous work on DFEA, the authors required the algorithm reach full consensus between factors during communication. In this paper, we demonstrate that even without full consensus, the performance of DFEA was not statistically different on problems with low epistasis. Additionally, we found that there is a relationship between the convergence of consensus between factors and the convergence of fitness of DFEA.
evolutionary algorithms (EAs), when used for global optimization, can be seen as unconstrained optimization techniques. Therefore, they require an additional mechanism to incorporate constraints of any kind (i.e., ine...
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ISBN:
(纸本)9781450343237
evolutionary algorithms (EAs), when used for global optimization, can be seen as unconstrained optimization techniques. Therefore, they require an additional mechanism to incorporate constraints of any kind (i.e., inequality, equality, linear, nonlinear) into their fitness function. Although the use of penalty functions (very popular with mathematical programming techniques) may seem an obvious choice, this sort of approach requires a careful fine tuning of the penalty factors to be used. Otherwise, an EA may be unable to reach the feasible region (if the penalty is too low) or may reach quickly the feasible region but being unable to locate solutions that lie in the boundary with the infeasible region (if the penalty is too severe). This has motivated the development of a number of approaches to incorporate constraints into the fitness function of an EA. This tutorial will cover the main proposals in current use, including novel approaches such as the use of tournament rules based on feasibility, multiobjective optimization concepts, hybrids with mathematical programming techniques (e.g., Lagrange multipliers), cultural algorithms, and artificial immune systems, among others. Other topics such as the importance of maintaining diversity, current benchmarks and the use of alternative search engines (e.g., particle swarm optimization, differential evolution, evolution strategies, etc.) will be also discussed (as time allows).
evolutionary algorithms (EAs) are a kind of stochastic optimization methods, which have been testified to be powerful in solving many real-world hard problems in past decades. But till now, we are still short of effec...
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ISBN:
(纸本)9781450343237
evolutionary algorithms (EAs) are a kind of stochastic optimization methods, which have been testified to be powerful in solving many real-world hard problems in past decades. But till now, we are still short of effective methods to represent and investigate their collective behaviors in various environments, which are very useful for researchers and engineers in evolutionary Computation to understand the algorithms better. This paper is a preliminary effort to tackle above issue. We attempt to analyze the generation-wise collective behavior of EAs via an approach called feature learning. An unsupervised feature learning framework based on Slow Feature Analysis (SFA) is presented to extract discriminative features from the generation-wise collective behavior data of several EAs on various fitness landscapes, with the purpose of finding out whether there exist differences between the searching behavior of different EAs running on the same fitness landscape;and whether there are differences between the behavior of one algorithm running on different fitness landscapes. Besides, the relationship between the fitness landscape and the searching behavior of EA is also studied. In the experiments, several typical EAs and classical benchmark functions with typical landscapes are selected as the study subjects. The collective behaviors of various EAs are visualized and compared in the extracted feature space.
In this article, we discuss the progress achieved with the use of evolutionary algorithms for the analysis of H-1 Nuclear Magnetic Resonance spectra of solutes in orientationally ordered liquids. With these tools the ...
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In this article, we discuss the progress achieved with the use of evolutionary algorithms for the analysis of H-1 Nuclear Magnetic Resonance spectra of solutes in orientationally ordered liquids. With these tools the analysis of extremely complex spectra that were hitherto impossible to solve has now become eminently feasible. We discuss applications to 2 molecules of special interest: (a) hexamethylbenzene, which is a text book example of steric hindrance between adjacent rotating methyl groups;and (b) cyclohexane which is the standard example of interconversion between various molecular conformations. New interesting physics is obtained in both cases.
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