Abstract

Electric Vehicles (EVs) are regarded to be among the most environmentally and economically efficient transportation solutions. However, barriers and range limitations hinder this technology’s progress and deployment. In this paper, we examine EV route planning to derive optimal routes considering energy consumption by analyzing historical trajectory data. More specifically, we propose a novel approach for EV route planning that considers real-time traffic incidents, road topology, charging station locations during battery failure, and finally, traffic flow prediction extracted from historical trajectory data to generate energy maps. Our approach consists of four phases: the off-line phase which aims to build the energy graph, the application of the A* algorithm to deliver the optimal EV path, the NEAT trajectory clustering which aims to produce dense trajectory clusters for a given period of the day, and finally, the on-line phase based on our algorithm to plan an optimal EV path based on real traffic incidents, dense trajectory clusters, road topology information, vehicle characteristics, and charging station locations. We set up experiments on real cases to establish the optimal route for electric cars, demonstrating the effectiveness and efficiency of our proposed algorithm.

Abstract

Code smells, also known as anti-patterns, are poor design or implementation choices that hinder program comprehensibility and maintainability. While several code smell detection methods have been proposed, Mantyla et al. identified the uncertainty issue as one of the major individual human factors that may affect developer’s decisions about the smelliness of software classes: they may indeed have different opinions mainly due to their different knowledge and expertise. Unfortunately, almost all the existing approaches assume data perfection and neglect the uncertainty when identifying the labels of the software classes. Ignoring or rejecting any uncertainty form could lead to a considerable loss of information, which could significantly deteriorate the effectiveness of the detection and identification processes. Inspired by our previous works and motivated by the interesting performance of the PDT (Possibilistic Decision Tree) in classifying uncertain data, we propose ADIPE (Anti-pattern Detection and Identification using Possibilistic decision tree Evolution), as a new tool that evolves and optimizes a set of detectors (PDTs) that could effectively deal with software class labels uncertainty using some concepts from the Possibility theory. ADIPE uses a PBE (Possibilistic Base of Examples: a dataset with possibilistic labels) that it is built using a set of opinion-based classifiers (i.e., a set of probabilistic classifiers) with the aim to simulate human developers’ uncertainty. A set of advisors and probabilistic classifiers are employed in order to mimic the subjectivity and the doubtfulness of software engineers. A detailed experimental study is conducted to show the merits and outperformance of ADIPE in dealing with uncertainty in code smells detection and identification with respect to four relevant state-of-the-art methods, including the baseline PDT. The experimental study was performed in uncertain and certain environments based on two suitable metrics: PF-measure_dist (Possibilistic F-measure_Distance) and IAC (Information Affinity Criterion); which corresponds to the F-measure and Accuracy (PCC) for the certain case. The obtained results for the uncertain environment reveal that for the detection process, the PF-measure_dist of ADIPE ranges within [0.9047 and 0.9285], and its IAC lies within [0.9288 and 0.9557]; while for the identification process, the PF-measure_dist of ADIPE is in [0.8545, 0.9228], and its IAC lies within [0.8751, 0.933]. ADIPE is able to find 35% more code smells with uncertain data than the second best algorithm (i.e., BLOP). In addition, ADIPE succeeds to decrease the number of false alarms (i.e., misclassified smelly instances) with a rate equals to 12%. Our proposed approach is also able to identify 43% more smell types than BLOP and decreases the number of false alarms with a rate equals to 32%. Similar results were obtained for the certain environment, which demonstrate the ability of ADIPE to also deal with the certain environment.

Abstract

Abstract

Improving sustainability in Pharmaceutical Supply Chain (PSC) becomes theprimary concern for its involved members. It lends major challenges to its management as it haseconomic, social, and environmental responsibilities more weighed than other supply chains.Providing the day-to-day need for medicines must be satisfied while taking into account theuse of the economic resource, customer satisfaction, and the impact of pharmaceutical wasteon the environment. Medicines waste affects healthcare expenses and harms the environment.Therefore, avoiding unused medication leftover through the pharmaceutical chain presents anefficient approach to attaining a sustainable supply of medicines. This article aims to deal withthe sustainability of a PSC by minimizing the deterioration rate of medicines at both distributorand hospitals sites. We propose an inventory management model based on a mixed-integernon-linear program (MINLP) that seeks the optimal replenishment order quantity of multipletypes of products and the shipment time in a two-echelon PSC consisting of a pharmaceuticalcompany (PC), a central pharmacy (CP), and multiple hospitals over a planning horizon, whileconsidering shipment costs, perishability, and shortage constraints.

Abstract

In this study, various organizations that have participated in several road path-detecting experimentsare analyzed. However, the majority of techniques rely on attributes or form models built by humans to identifysections of the path. In this paper, a suggestion was made regarding a road path recognition structure that is dependenton a deep convolutional neural network. A tiny neural network has been developed to perform feature extraction toa massive collection of photographs to extract the suitable path feature. The parameters obtained from the model ofthe route classification network are utilized in the process of establishing the parameters of the layers that constitutethe path detection network. The deep convolutional path discovery network’s production is pixel-based and focuseson the identification of path types and positions. To train it, a detection failure job is provided. Failure in pathclassification and regression are the two components that make up a planned detection failure function. Instead oflaborious postprocessing, a straightforward solution to the problem of route marking can be found using observedpath pixels in conjunction with a consensus of random examples. According to the findings of the experiments, theclassification precision of the network for classifying every kind is higher than 98.3%. The simulation that was trainedusing the suggested detection failure function is capable of achieving an accuracy of detection that is 85.5% over atotal of 30 distinct scenarios on the road

Abstract

Cost-sensitive learning is one of the most adopted approaches to deal with data imbalance in classification. Unfortunately, the manual definition of misclassification costs is still a very complicated task, especially with the lack of domain knowledge. To deal with the issue of costs’ uncertainty, some researchers proposed the use of intervals instead of scalar values. This way, each cost would be delimited by two bounds. Nevertheless, the definition of these bounds remains as a very complicated and challenging task. Recently, some researches proposed the use of genetic programming to simultaneously build classification trees and search for optimal costs’ bounds. As for any classification tree there is a whole search space of costs’ bounds, we propose in this paper a bi-level evolutionary approach for interval-based cost-sensitive classification tree induction where the trees are constructed at the upper level while misclassification costs intervals bounds are optimized at the lower level. This ensures not only a precise evaluation of each tree but also an effective approximation of optimal costs intervals bounds. The performance and merits of our proposal are shown through a detailed comparative experimental study on commonly used imbalanced benchmark data sets with respect to several existing works.

Abstract

Discretization-based feature selection (DBFS) approaches have shown interesting results when using several metaheuristic algorithms, such as particle swarm optimization (PSO), genetic algorithm (GA), ant colony optimization (ACO), etc. However, these methods share the same shortcoming which consists in encoding the problem solution as a sequence of cut-points. From this cut-points vector, the decision of deleting or selecting any feature is induced. Indeed, the number of generated cut-points varies from one feature to another. Thus, the higher the number of cut-points, the higher the probability of selecting the considered feature; and vice versa. This fact leads to the deletion of possibly important features having a single or a low number of cut-points, such as the infection rate, the glycemia level, and the blood pressure. In order to solve the issue of the dependency relation between the feature selection (or removal) event and the number of its generated potential cut-points, we propose to model the DBFS task as a bilevel optimization problem and then solve it using an improved version of an existing co-evolutionary algorithm, named I-CEMBA. The latter ensures the variation of the number of features during the migration process in order to deal with the multimodality aspect. The resulting algorithm, termed bilevel discretization-based feature selection (Bi-DFS), performs selection at the upper level while discretization is done at the lower level. The experimental results on several high-dimensional datasets show that Bi-DFS outperforms relevant state-of-the-art methods in terms of classification accuracy, generalization ability, and feature selection bias.

Abstract

Data imbalance is still so far a challenging issue in data classification. In literature, cost-sensitive approach has been used to deal with such a challenge. Despite its interesting results, the manual design of cost matrices is still the main shortcoming of this approach. The data engineer is still facing a great difficulty in defining the misclassification costs, especially with the absence of domain specific knowledge. Recent works suggest the use of genetic programming as an effective tool to design classification trees with automatically learned costs. Although promising results were obtained, evaluating a classification tree with a single cost matrix is not a wise choice. Indeed, the tree quality evaluation requires trying several misclassification cost matrices to be more precise and fair. Motivated by this observation, we propose in this paper a bi-level modeling of the cost-sensitive classification tree induction problem where the upper level evolves the classification trees, while the cost matrix of each tree is optimized at the lower level. Our bi-level modeling is solved using an existing co-evolutionary algorithm, and the resulting method is named Bi-COS. The obtained comparative experimental results on several imbalanced benchmark datasets show the merits of Bi-COS with respect to the state-of-the art.

Abstract

In many decision making cases, we may have a hierarchical situation between different optimization tasks. For instance, in production scheduling, the evaluation of the tasks assignment to a machine requires the determination of their optimal sequencing on this machine. Such situation is usually modeled as a Bi-Level Optimization Problem (BLOP). The latter consists in optimizing an upper-level (a leader) task, while having a lower-level (a follower) optimization task as a constraint. In this way, the evaluation of any upper-level solution requires finding its corresponding lower-level (near) optimal solution, which makes BLOP resolution very computationally costly. Evolutionary Algorithms (EAs) have proven their strength in solving BLOPs due to their insensitivity to the mathematical features of the objective functions such as non-linearity, non-differentiability, and high dimensionality. Moreover, EAs that are based on approximation techniques have proven their strength in solving BLOPs. Nevertheless, their application has been restricted to the continuous case as most approaches are based on approximating the lower-level optimum using classical mathematical programming and machine learning techniques. Motivated by this observation, we tackle in this paper the discrete case by proposing a Co-Evolutionary Migration-Based Algorithm, called CEMBA, that uses two populations in each level and a migration scheme; with the aim to considerably minimize the number of Function Evaluations (FEs) while ensuring good convergence towards the global optimum of the upper-level. CEMBA has been validated on a set of bi-level combinatorial production-distribution planning benchmark instances. The statistical analysis of the obtained results shows the effectiveness and efficiency of CEMBA when compared to existing state-of-the-art combinatorial bi-level EAs.

Abstract

Context. This paper deals with bilateral joint decision making in supply chains, and more specifically focuses on coordinating the decisions taken by the supplier and the producer in lot sizing. Research gap. Previous existing works in lot sizing have modeled the coordination task as a bi-level optimization problem. Unfortunately, the bi-level model causes a hierarchy between the two actors by making the leader imposing the decisions that suits his/her interests to the follower. This induces a significant conflict of interest between the two stakeholders because the leaders benefit is always greater than the follower’s one. Objective. The main goal of this work is to attenuate the conflict of interest issue between both actors by proposing a multi-objective model that alleviates the hierarchy and creates a win–win situation. Method. We propose an effective multi-objective lot sizing model, called Supplier-Producer Multi-Objective Lot Sizing (SP-MOLS); that alleviates the hierarchy between the actors’ objectives by assigning them the same importance degree and hence optimizing them simultaneously. The resolution of our SP-MOLS model using the Non-dominated Sorting Genetic Algorithm II (NSGA-II), as an effective meta-heuristic search engine, provides a set of trade-off solutions, each expressing a compromise degree between the two actors: the supplier and the producer. Results. To validate our approach, we use five test problems each containing 100 instances with a planning horizon of 10 periods and we analyze the obtained trade-off solutions using the compromise degree and the gap between costs as main consensus metrics. The obtained results reveal that a small sacrifice in the leader’s benefit could produce a significant improvement in the follower’s one. For instance, a 10% increase of the producer’s cost may generate a 42% decrease in the supplier’s one. Reciprocally, a 0.4% increase of the supplier’s cost may generate a 49% decrease in the producer’s cost. Method algorithmic improvement. As solutions of interests for both stakeholders are usually located within the extreme regions of the Pareto front, we propose NSGA-II with Focus on Extreme Regions (NSGA-II-FER) as a new variant of NSGA-II that focuses the search in the extreme regions of the Pareto front thanks to a modified crowding measure that is adaptively managed during the evolution process. This variant has shown its ability to eliminate dominance-resistant solutions and thus to come up with better extreme regions. Based on the experimental results, NSGA-II-FER is shown to have the ability to provide the decision makers with more convergent and more diversified extreme non-dominated solutions, expressing better trade-off degrees between both actors’ costs. Managerial implications. The promising results obtained by our proposal encourage decision makers’ to adopt a multi-objective approach rather than a bi-level one. From our personal perspective, we recommend running the three models (the multi-objective model and the two bi-levels ones); then analyzing the solutions of all models in terms of compromise degrees and logistic costs. This would allow both actors to observe how the hierarchy incurred by the bi-level models increases conflicts, while the multi-objective one generates solutions with much improved consensus degrees. Such observations will convince the supply chain stakeholders to adopt our multi-objective approach, while keeping an eye on the bi-level models’ solutions and the consensus degrees. Finally, we also recommend focusing on the extreme regions of the Pareto front since they contain rich solutions in terms of consensus. Such solutions are more convincing in the negotiation process and thus could lead to better win–win situations.