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Recent advances in technology and devices have caused a data explosion on the Internet and on our home PCs. This data is predominantly obtained in various modalities (text, image, video, etc.) and is essential for e-commerce websites. The products on these websites have both images and descriptions in text form, making them multimodal in nature. Earlier categorization and information retrieval methods focused mostly on a single modality. This study employs multimodal data for classification using neutrosophic fuzzy sets for uncertainty management for information retrieval tasks. This effort utilizes image and text data and, inspired by past techniques of embedding text over an image, attempts to classify the images using neutrosophic classification algorithms. For classification tasks, Neutrosophic Convolutional Neural Networks (NCNNs) are used to learn feature representations of the produced images. We demonstrate how a pipeline based on NCNN can be utilized to learn representations of the innovative fusion method. Traditional convolutional neural networks are vulnerable to unknown noisy conditions in the test phase, and as a result, their performance for the classification of noisy data declines. Comparing our method against individual sources on two large-scale multi-modal categorization datasets yielded good results. In addition, we have compared our method to two well-known multi-modal fusion methodologies, namely early fusion and late fusion. [ABSTRACT FROM AUTHOR]

Abstract: A constraint satisfaction problem (CSP) is a generic problem with many applications in different areas of artificial intelligence and operational research. During the search for a solution, the order in which the variables are selected to be instantiated has a tremendous impact in the complexity of the search. Many heuristics exist for ordering these variables, but they are specialized for some types of instances. Hyper-heuristics are methodologies used to choose from a set of heuristics and decide which one to apply given some properties of the instance at hand. In this research, we propose a new type of hyper-heuristic based on a learning vector quantization (LVQ) neural network for variable ordering within CSP. The first part of the investigation describes a methodology to generate LVQ neural networks that are able to map some properties of the instances to one suitable variable ordering heuristic. Later, the networks are created according to such methodology and tested on random and real instances proving that they are a feasible method to improve the performance of search on CSP when compared to single heuristics applied in isolation. [Copyright &y& Elsevier]

Security has become a critical issue for complex and expensive systems and day-to-day situations. In this regard, the analysis of surveillance cameras is a critical issue usually restricted to the number of people devoted to such a task, their knowledge and judgment. Nonetheless, different approaches have arisen to automate this task in recent years. These approaches are mainly based on machine learning and benefit from developing neural networks capable of extracting underlying information from input videos. Despite how competent those networks have proved to be, developers must face the challenging task of defining both the architecture and hyperparameters that allow such networks to work adequately and optimize the use of computational resources. In short, this work proposes a model that generates, through a genetic algorithm, neural networks for behavior classification within videos. Two types of neural networks evolved as part of this work, shallow and deep, which are structured on dense and 3D convolutional layers. Each network requires a particular type of input data: the evolution of the pose of people in the video and video sequences, respectively. Shallow neural networks use a direct encoding approach to map each part of the chromosome into a phenotype. In contrast, deep neural networks use indirect encoding, blueprints representing entire networks, and modules to depict layers and their connections. Our approach obtained relevant results when tested on the Kranok-NV dataset and evaluated with standard metrics used for similar classification tasks. [ABSTRACT FROM AUTHOR]

Constraint satisfaction problems are of special interest for the artificial intelligence and operations research community due to their many applications. Although heuristics involved in solving these problems have largely been studied in the past, little is known about the relation between instances and the respective performance of the heuristics used to solve them. This paper focuses on both the exploration of the instance space to identify relations between instances and good performing heuristics and how to use such relations to improve the search. Firstly, the document describes a methodology to explore the instance space of constraint satisfaction problems and evaluate the corresponding performance of six variable ordering heuristics for such instances in order to find regions on the instance space where some heuristics outperform the others. Analyzing such regions favors the understanding of how these heuristics work and contribute to their improvement. Secondly, we use the information gathered from the first stage to predict the most suitable heuristic to use according to the features of the instance currently being solved. This approach proved to be competitive when compared against the heuristics applied in isolation on both randomly generated and structured instances of constraint satisfaction problems. [ABSTRACT FROM AUTHOR]

This paper proposes an adaptation, to the two-dimensional irregular bin packing problem of the Djang and Finch heuristic (DJD), originally designed for the one-dimensional bin packing problem. In the two-dimensional case, not only is it the case that the piece's size is important but its shape also has a significant influence. Therefore, DJD as a selection heuristic has to be paired with a placement heuristic to completely construct a solution to the underlying packing problem. A successful adaptation of the DJD requires a routine to reduce computational costs, which is also proposed and successfully tested in this paper. Results, on a wide variety of instance types with convex polygons, are found to be significantly better than those produced by more conventional selection heuristics. [ABSTRACT FROM AUTHOR]

Hyperheuristics rise as powerful techniques that get good results in less computational time than exact methods like dynamic programming or branch and bound. These exact methods promise the global best solution, but with a high computational time. In this matter, hyperheuristics do not promise the global best solution, but they promise a good solution in a lot less computational time. On the contrary, fuzzy logic provides the tools to model complex problems in a more natural way. With this in mind, this paper proposes a fuzzy hyperheuristic approach, which is a combination of a fuzzy inference system with a selection hyperheuristic. The fuzzy system needs the optimization of its fuzzy rules due to the lack of expert knowledge; indeed, traditional hyperheuristics also need an optimization of their rules. The fuzzy rules are optimized by genetic algorithms, and for the rules of the traditional methods, we use particle swarm optimization. The genetic algorithm will also reduce the number of fuzzy rules, in order to find the best minimal fuzzy rules, whereas traditional methods already use very few rules. Experimental results show the advantage of using our approach instead of a traditional selection hyperheuristic in 3200 instances of the 0/1 knapsack problem. [ABSTRACT FROM AUTHOR]

The assessment of strengths and weaknesses of a solver is often limited by the diversity of the cases where it is tested upon. As such, it is paramount to have a versatile tool which finds the problem instances where such a solver excels/fails. In this manuscript, we propose to use an evolutionary algorithm for creating this tool. To validate our approach, we conducted several tests on four heuristics for the knapsack problem. Although, the process can be extended to other domains with relatively few changes. The tests cover different sets of instances, both favoring the performance of one heuristic while hindering that of the remaining ones, and vice versa. To further test our evolutionary-based model, we also apply it on a recent approach that combines the strengths of different heuristics to improve its performance (usually referred to as a hyper-heuristic). We show that it is possible to tailor instances in which even this more complex model excels/fails. Throughout our approach, a researcher can test a solver under different kinds of scenarios, delving deeper into the conditions that make it perform well/poorly. Therefore, we recommend using the proposed approach as a means to grasp better insights about strengths and weaknesses of different solvers. [ABSTRACT FROM AUTHOR]

Highlights • A new method to solve vehicle routing through meta-learning techniques. • Two sets of meta-features are used: basic and landmarking meta-features. • A multilayer perceptron classifier is used to select meta-heuristics. • Our proposal statistically improves the overall performances previously reported. Abstract This paper describes a method for solving vehicle routing problems with time windows, based on selecting meta-heuristics via meta-learning. Although several meta-heuristics already exist that can obtain good overall results on some vehicle routing problem instances, none of them performs well in all cases. By defining a set of meta-features that appropriately characterize different routing problem instances and using a suitable classifier, our model can often correctly predict the best meta-heuristic for each instance. The main contributions of this paper are the definition of two meta-feature sets, one based on what we call 'basic' instance properties and another based on the number of feasible solutions found by perturbative heuristics via a greedy process. We use a multilayer perceptron classifier, combined with a wrapper meta-feature selection method, to predict the most suitable meta-heuristic to apply to a given problem instance. Our experimental results show that the proposed method can significantly improve upon the overall performance of well-known meta-heuristics in the field. Therefore, this paper proposes to store, share and exploit in an off-line scheme the solutions obtained in instances of different scenarios such as the academy or industry, with the aim of predicting good solvers for new instances when necessary. [ABSTRACT FROM AUTHOR]

A cluster validity index is used to select which clustering algorithm to apply for a given problem. It works by evaluating the quality of a partition, as output by a candidate clustering algorithm, getting around the common case of the lack of an expert in the given domain of discourse. Most existing validity indexes make assumptions, such as each cluster of the partition having an underlying structure, for example, a hypersphere, yielding incorrect evaluations when they do not hold. Here, we propose a new cluster validity index, which attempts to avoid this bias using an ensemble of distinct supervised classifiers; this way the bias is not attributable to a specific classifier, but to a collection thereof, hence alleviating the problem. The rationale behind our index is that a good partition should induce the construction of also a good classifier; the better the classification performance, the better the quality of the partition under evaluation. Notice how we use the partition to be assessed as a sort of labeled dataset, where each object is labeled with the cluster label it belongs to. We have tested our index on 50 numerical datasets, grouped using six different clustering algorithms. In our experiments, our index outperforms five validity indexes, including the most popular ones. [ABSTRACT FROM AUTHOR]

When solving constraint satisfaction problems (CSPs), it is a common practice to rely on heuristics to decide which variable should be instantiated at each stage of the search. But, this ordering influences the search cost. Even so, and to the best of our knowledge, no earlier work has dealt with how first variable orderings affect the overall cost. In this paper, we explore the cost of finding high-quality orderings of variables within constraint satisfaction problems. We also study differences among the orderings produced by some commonly used heuristics and the way bad first decisions affect the search cost. One of the most important findings of this work confirms the paramount importance of first decisions. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. We propose a simple method to improve early decisions of heuristics. By using it, performance of heuristics increases. [ABSTRACT FROM AUTHOR]

• Features of initial solutions predict the performance of perturbation algorithms. • Low performance variation within portfolios makes algorithm selection difficult. • Hybrid selection models are useful for portfolios with low performance variation. • Accuracy is not a fair measure to evaluate the performance of algorithm selectors. In this paper, we present the construction process of a per-instance algorithm selection model to improve the initial solutions of Curriculum-Based Course Timetabling (CB-CTT) instances. Following the meta-learning framework, we apply a hybrid approach that integrates the predictions of a classifier and linear regression models to estimate and compare the performance of four meta-heuristics across different problem sub-spaces described by seven types of features. Rather than reporting the average accuracy, we evaluate the model using the closed SBS-VBS gap, a performance measure used at international algorithm selection competitions. The experimental results show that our model obtains a performance of 0.386, within the range obtained by per-instance algorithm selection models in other combinatorial problems. As a result of the process, we conclude that the performance variation between the meta-heuristics has a significant role in the effectiveness of the model. Therefore, we introduce statistical analyses to evaluate this factor within per-instance algorithm portfolios. [ABSTRACT FROM AUTHOR]

Metaheuristics have become a widely used approach for solving a variety of practical problems. The literature is full of diverse metaheuristics based on outstanding ideas and with proven excellent capabilities. Nonetheless, oftentimes metaheuristics claim novelty when they are just recombining elements from other methods. Hence, the need for a standard metaheuristic model is vital to stop the current frenetic tendency of proposing methods chiefly based on their inspirational source. This work introduces a first step to a generalised and mathematically formal metaheuristic model, which can be used for studying and improving them. This model is based on a scheme of simple heuristics, which perform as building blocks that can be modified depending on the application. For this purpose, we define and detail all components and concepts of a metaheuristic (i.e., its search operators), such as heuristics. Furthermore, we also provide some ideas to take into account for exploring other search operator configurations in the future. To illustrate the proposed model, we analyse search operators from four well-known metaheuristics employed in continuous optimisation problems as a proof-of-concept. From them, we derive 20 different approaches and use them for solving some benchmark functions with different landscapes. Data show the remarkable capability of our methodology for building metaheuristics and detecting which operator to choose depending on the problem to solve. Moreover, we outline and discuss several future extensions of this model to various problem and solver domains. [ABSTRACT FROM AUTHOR]