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Applied Soft Computing
Elsevier Science, B.V.
Applied Soft Computing

Elsevier Science, B.V.

1568-4946

Applied Soft Computing/Journal Applied Soft ComputingEIISTPSCIAHCI
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    Multi-agent based sine-cosine algorithm for optimal integration of DERs with consideration of existing OLTC in distribution networks

    Patel, C. D.Tailor, T. K.
    17页
    查看更多>>摘要:In this work, a modified version of the sine-cosine algorithm (SCA) has been developed to solve complex optimization problems. This proposed modified algorithm integrates the multi-agent system and sine-cosine algorithm and is termed as multi-agent sine-cosine algorithm (MA-SCA). This work also proposes a simplified strategy for the self-learning operator and modification in inversion operator. These proposed modifications have been validated by implementing the proposed MA-SCA algorithm on standard functions and comparing results with other reported optimization methods. Furthermore, in this work, MA-SCA algorithm has also been applied to optimally deploy the distributed energy resources (DERs) and shunt capacitors (SCs) in the distribution network with and without consideration of the existing on-load tap changing transformer (OLTC). The considered objectives in this optimization problem are reduction of cost of annual energy loss (CAEL) and minimization of voltage deviation under different loading conditions. To demonstrate the efficacy of the MA-SCA algorithm, it has been implemented on IEEE 33 bus radial distribution network (DN) and real-life Indian 108 bus radial DN. The comparison of obtained results with the results obtained by using other optimization methods has been carried out, and it indicates that MA-SCA algorithm provides the improved solution. (C) 2021 Elsevier B.V. All rights reserved.

    A full-featured cooperative coevolutionary memory-based artificial immune system for dynamic optimization

    Etaati, BaharehGhorrati, ZahraEbadzadeh, Mohammad Mehdi
    14页
    查看更多>>摘要:In this paper, a novel cooperative coevolutionary memory-based artificial immune system enhanced by a new clonal selection algorithm is proposed for dynamic optimization problems. In the proposed algorithm, the whole n-dimensional population is decomposed into n one-dimensional subpopulations. Then, each subpopulation is evaluated separately using a set of context vectors called short-term memory. Also, inspired by the production of new cells in bone marrow, each subpopulation is divided into multiple regions to track and locate multiple optima cooperatively. This division helps the algorithm exploit search space effectively. Additionally, inspired by the immune memory concept, a memory-based approach called long-term memory is proposed to store and retrieve essential information when a fitness change occurs. Furthermore, a new clonal selection method, a combination of negative selection and clonal selection mechanisms, is proposed. This proposed algorithm is faster than the basic clonal selection algorithm. Finally, compared to other immune-based algorithms, which usually are implemented based on one or two qualities of the biologic immune system, the proposed approach exploit almost all immune qualities. Several experiments are conducted on different configurations of the moving peaks benchmark to examine the efficiency of the proposed method. The experimental results confirm that the proposed method is competitive with other state-of-the-art algorithms to optimize dynamic problems. (C) 2022 Elsevier B.V. All rights reserved.

    Interpretability in the medical field: A systematic mapping and review study

    Hakkoum, HajarAbnane, IbtissamIdri, Ali
    23页
    查看更多>>摘要:Context: Recently, the machine learning (ML) field has been rapidly growing, mainly owing to the availability of historical datasets and advanced computational power. This growth is still facing a set of challenges, such as the interpretability of ML models. In particular, in the medical field, interpretability is a real bottleneck to the use of ML by physicians. Therefore, numerous interpretability techniques have been proposed and evaluated to help ML gain the trust of its users. Methods: This review was carried out according to the well-known systematic map and review process to analyze the literature on interpretability techniques when applied in the medical field with regard to different aspects: publication venues and publication year, contribution and empirical types, medical and ML disciplines and objectives, ML black-box techniques interpreted, interpretability techniques investigated, their performance and the best performing techniques, and lastly, the datasets used when evaluating interpretability techniques. Results: A total of 179 articles (1994-2020) were selected from six digital libraries: ScienceDirect, IEEE Xplore, ACM Digital Library, SpringerLink, Wiley, and Google Scholar. The results showed that the number of studies dealing with interpretability increased over the years with a dominance of solution proposals and experiment-based empirical type. Diagnosis, oncology, and classification were the most frequent medical task, discipline, and ML objective studied, respectively. Artificial neural networks were the most widely used ML black-box techniques investigated for interpretability. Additionally, global interpretability techniques focusing on a specific black-box model, such as rules, were the dominant explanation types, and most of the metrics used to evaluate interpretability were accuracy, fidelity, and number of rules. Moreover, the variety of the techniques used by the selected papers did not allow categorization at the technique level, and the high number of the sum of evaluations (671) of the articles raised a suspicion of subjectivity. Datasets that contained numerical and categorical attributes were the most frequently used in the selected studies. Conclusions: Further effort is needed in disciplines other than diagnosis and classification. Global techniques such as rules are the most used because of their comprehensibility to doctors, but new local techniques should be explored more in the medical field to gain more insights into the model's behavior. More experiments and comparisons against existing techniques are encouraged to determine the best performing techniques. Lastly, quantitative evaluation of interpretability and physicians' implications in interpretability techniques evaluation is highly recommended to evaluate how the techniques will perform in real-world scenarios. It can ensure the soundness of the techniques and help gain trust in black-box models in medical environments. (C) 2022 Elsevier B.V. All rights reserved.

    An electrocorticographic decoder for arm movement for brain-machine interface using an echo state network and Gaussian readout

    Kim, Hoon-HeeJeong, Jaeseung
    13页
    查看更多>>摘要:Brain-machine interface (BMI) studies typically use an electrocorticogram (ECoG) to record neural signals from the surface of the cortex because of the high spatial and temporal resolution and high signal-to-noise levels of the data obtained. However, in certain medical conditions, it may not be possible to place the ECoG electrodes at the target brain regions for BMI. Consequently, developing an ECoG decoder with suitable feature extraction and selection processes is challenging. This study investigated the possibility of a novel ECoG decoder for arm movement BMI. The ECoG signals were recorded from four individuals with intractable epilepsy while imaging and performing a reach-andgrasp movement. We examined the performance of the ECoG decoder using an echo state network and 24 Gaussian readouts within the classification problem paradigm of the arm movement directions. A genetic algorithm was used to optimize the hyperparameters of the ECoG decoder. The ECoG decoder successfully classified 24 arm movement directions in the x-y, x-z, and y-z planes in execution and imagination tasks. The best hit rates were 90.9 +/- 5.3 %, 92.6 +/- 3.9, and 92.6 +/- 4.2 for the x-y, x-z, and y-z planes, respectively. A robot arm control simulation indicated that a real-time movement BMI system could use the novel ECoG decoder. Thus, the echo state network with Gaussian readouts for classification can be a successful ECoG decoder model for motor BMIs. (C) 2021 Published by Elsevier B.V.

    Linear Ordering Problem based Classifier Chain using Genetic Algorithm for multi-label classification

    Mishra, Nitin KumarSingh, Pramod Kumar
    15页
    查看更多>>摘要:One of the most challenging tasks in multi-label classification is to identify label interdependence. Classifier Chain is the most prevalent method that utilizes label interdependence for improving classification accuracy as it requires only the number of classifiers equal to the number of labels. It uses a random sequence of labels. However, the order of labels in these sequences affects the classification performance. Nevertheless, despite many proposals in the literature, deciding the order in which these classifiers provide optimum results is a challenge to date. This paper proposes two methods for the ordering problem of the Classifier chain. The first proposed method termed as Linear Ordering Problem based Classifier Chain (LOP-CC) finds the chain order by considering it as a Linear Ordering Problem (LOP). The LOP utilizes a matrix and finds the optimal permutation of rows and corresponding columns that maximizes the sum of all the elements in the upper triangular matrix. This paper utilizes pairwise conditional entropy for creating the matrix to be used with the LOP and solves it using the Genetic Algorithm. It also proposes an extension to LOP-CC method termed as Linear Ordering Problem based partial Classifier Chain (LOP-pCC). It uses the same order of labels as LOP-CC. However, as opposed to LOP-CC, it utilizes partial sequences in the classifier chain rather than a full sequence. Experimentation performed on ten benchmark datasets consisting of a varying number of labels using different performance metrics demonstrates the proposed methods' effectiveness compared to the other state-of-the-art classifier chain models.(c) 2021 Elsevier B.V. All rights reserved.

    Contrastive learning based self-supervised time-series analysis

    Poppelbaum, JohannesChadha, Gavneet SinghSchwung, Andreas
    14页
    查看更多>>摘要:Deep learning architectures usually require large scale labeled datasets for achieving good performance on general classification tasks including computer vision and natural language processing. Recent techniques of self-supervised learning have opened up new a research frontier where deep learning architectures can learn general features from unlabeled data. The task of self-supervised learning is usually accomplished with some sort of data augmentation through which the deep neural networks can extract relevant information. This paper presents a novel approach for self-supervised learning based time-series analysis based on the SimCLR contrastive learning. We present novel data augmentation techniques, focusing especially on time-series data, and study their effect on the prediction task. We provide comparison with several fault classification approaches on benchmark Tennessee Eastman dataset and report an improvement to 81.43% in the final accuracy using our contrastive learning approach. Furthermore we report a new benchmark of 80.80%, 81.05% and 81.43% for self-supervised training on Tennesee Eastman where a classifier is only trained with 5%, 10% or 50% percent of the available training data. Hence, we can conclude that the contrastive approach is very successful in time-series problems also, and further suitable for usage with partially labeled time-series datasets.(c) 2022 Elsevier B.V. All rights reserved.

    Reliability analysis and ABC based optimization for CoMP-enabled systems over Nakagami-m fading

    Chen, JianWang, TaoJia, JieGuo, Liang...
    15页
    查看更多>>摘要:Providing reliable communications has become one of the major goals for machine-type-oriented applications. In this article, reliable analysis and joint optimization over Nakagami-m fading are investigated for coordinated multi-point (CoMP) assisted multi-cell systems. First, the reliability analysis model for user equipment (UE) served by multiple base stations (BSs) via CoMP technique over Nakagami-m fading is presented. The exact closed-form expression for reliability estimation based on the received signal-to-interference-plus-noise ratio (SINR) value over Nakagami-m fading is derived and verified. Then, the joint sub-carrier assignment and power allocation problem for reliability optimization is formulated. The formulated problem is proved to be NP-hard. Bio-inspired artificial bee colony algorithm (ABC) is thus invoked to tackle this problem, and three ABC based joint optimization frameworks, namely Two-Step ABC Optimization algorithm (TSABC), ABC Combinatorial Optimization algorithm (ABCCO), and Heuristic Two-Step Optimization algorithm (HTSO), are proposed. Simulation results show that the UE reliability can be significantly enhanced by these proposed frameworks. It is also showcased that the proposed ABCCO obtains optimized reliability of 16 nines within 700 generations for most scenarios, which outperforms TSABC, HTSO, and conventional genetic algorithm (GA). (C) 2021 Published by Elsevier B.V.

    Multi-objective optimization algorithm assisted by metamodels with applications in aerodynamics problems

    Gautier, Nelson Jose DiazManzanare Filho, NelsonRamirez, Edna Raimunda da Silva
    17页
    查看更多>>摘要:The optimization algorithms when used in real engineering problems involving high fidelity numeric simulations often require a large number of numerical assessments to achieve a good approximation of the optimal solution. The computational time needed to find this solution may be unfeasible in these problems. The metamodel assisted algorithms have been used to accelerate optimization problems using different strategies to find the optimum. For single objective problems, CORS (Constrained Optimization using Response Surfaces) was developed with basis on the iterative generation of distance constraints to explore and exploit the design space, such that convergence to a global optimum is mathematically guaranteed. In this paper, a multi-objective optimization strategy based on metamodel construction using radial basis functions, MO-CORS, is presented. It takes the advantage of the CORS strategy in multi-objective problems to perform the effective detection of the non-dominated set extreme points, for the subsequent filling of empty spaces between these extremes. Metamodels are used strategically in an iterative sampling process to guide the search for better solutions and to determine where in the domain the next objective function evaluations should be performed. The evaluations carried out on the expensive functions also allow improving metamodel construction in the promising regions at each iteration. Results obtained in test problems and in aerodynamic problems applications show that the developed algorithm is an effective tool to accelerate single and multi objective optimization problems and that the use of the CORS strategy inside MO-CORS was relevant in helping it to attain solutions not found by other optimization algorithms. (C) 2022 Elsevier B.V. All rights reserved.

    A judgment-based model for usability evaluating of interactive systems using fuzzy Multi Factors Evaluation (MFE)

    Asemi, AdelehAsemi, Asefeh
    17页
    查看更多>>摘要:The study aimed to propose a judgment-based evaluation model for usability evaluating of interactive systems. Human judgment is associated with uncertainty and gray information. We used the fuzzy technique for integration, summarization, and distance calculation of quality value judgment. The proposed model is an integrated fuzzy Multi Factors Evaluation (MFE) model based on experts' judgments in HCI, ISPD, and AMLMs. We provided a Fuzzy Inference System (FIS) for scoring usability evaluation metrics in different interactive systems. A multi-model interactive system is implemented for experimental testing of the model. The achieved results from the proposed model and experimental tests are compared using statistical correlation tests. The results show the ability of the proposed model for usability evaluation of interactive systems without the need for conducting empirical tests. It is concluded that applying a dataset in a neuro-FIS and training system cause to produce more than a hundred effective rules. The findings indicate that the proposed model can be applied for interactive system evaluation, informative evaluation, and complex empirical tests. Future studies may improve the FIS with the integration of artificial neural networks. (C) 2022 The Author(s). Published by Elsevier B.V.

    Ada: Adversarial learning based data augmentation for malicious users detection

    Wang, JiaGao, MinWang, ZongweiLin, Chenghua...
    11页
    查看更多>>摘要:Malicious user detection in the recommender systems has attracted much attention in the last two decades because malicious users can seriously affect the recommendation results and user experience. The up-to-date detection models usually concentrate on distinguishing users according to their latent features represented in user embeddings. These models can improve detection performance; however, they are usually not fully up to expectations, especially in the scenarios with unbalanced use samples. From these models that concentrate on user embedding representations, we can summarize the following difficulties: (1) the cost of manual labeling malicious causes the lack of labeled malicious users in training data, which leads to imprecise representations of users; (2) current augmentation methods that aim at mitigating the lack of labeled malicious users are hard to simulate the distribution of malicious users. In this paper, we propose a detection model, using adversarial learning based data augmentation (a.k.a. Ada) to alleviate these problems. Concretely, to get precise representations of users, the model integrates potential user relations and structural similarities into user embeddings. After obtaining precise user representation, it presents a novel data augmentation based on the deep convolutional generative adversarial networks (DCGAN) to simulate the distribution of malicious user embeddings and generate additional fake user embeddings. Experiments on public datasets show our model outperforms state-of-the-art detection models with sparse labeled malicious users, and the ablation study confirms the importance and effectiveness of each component of the model.(C) 2022 Elsevier B.V. All rights reserved.