4.7 Article

Curvature-based method for determining the number of clusters

Journal

INFORMATION SCIENCES
Volume 415, Issue -, Pages 414-428

Publisher

ELSEVIER SCIENCE INC
DOI: 10.1016/j.ins.2017.05.024

Keywords

k-Means clustering; Number of clusters; Cluster analysis; Gap statistic; Hartigan's rule

Funding

  1. Nanyang Technological University Research Scholarship

Ask authors/readers for more resources

Determining the number of clusters is one of the research questions attracting considerable interests in recent years. Majority of the existing methods require parametric assumptions and substantiated computations. In this paper we propose a simple yet powerful method for determining the number of clusters based on curvature. Our technique is computationally efficient and straightforward to implement. We compare our method with 6 other approaches on a wide range of simulated and real-world datasets. Theoretical motivation underlying the proposed method is also presented. (C) 2017 Elsevier Inc. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

Article Computer Science, Artificial Intelligence

RS-HeRR: a rough set-based Hebbian rule reduction neuro-fuzzy system

Feng Liu, Arif Ahmed Sekh, Chai Quek, Geok See Ng, Dilip K. Prasad

Summary: This paper introduces a hybrid fuzzy-rough set approach called RS-HeRR for generating effective, interpretable, and compact rule sets. It combines a powerful rule generation and reduction fuzzy system and improves system performance by reducing partial dependencies in rules.

NEURAL COMPUTING & APPLICATIONS (2021)

Article Computer Science, Artificial Intelligence

A Novel Quasi-Newton Method for Composite Convex Minimization

W. H. Chai, S. S. Ho, H. C. Quek

Summary: A fast parallelable Jacobi iteration type optimization method is proposed for non-smooth convex composite optimization, which integrates both first and second-order techniques to boost convergence speed. Experimental results show that the proposed method converges significantly better than existing methods.

PATTERN RECOGNITION (2022)

Article Computer Science, Information Systems

Representation recovery via L1-norm minimization with corrupted data

Woon Huei Chai, Shen-Shyang Ho, Hiok Chai Quek

Summary: This paper studies the recovery probability of the state-of-the-art sparse recovery method YALL1 and provides a generalization of a theoretical work based on a special case of YALL1 optimization problem. The results show that not only the special case but also some other cases of YALL1 optimization problem can recover any sufficiently sparse coefficient vector under certain conditions. The trade-off parameter in YALL1 allows the recovery probability to be optimally tuned. Experimental results demonstrate the superiority of YALL1 optimization problem with primal augmented Lagrangian optimization technique in terms of speed.

INFORMATION SCIENCES (2022)

Article Computer Science, Artificial Intelligence

Dynamic portfolio rebalancing through reinforcement learning

Qing Yang Eddy Lim, Qi Cao, Chai Quek

Summary: This study introduces Reinforcement Learning and dynamic portfolio rebalancing to enhance portfolio management efficiency, adapting portfolios dynamically to market trends, risks, and returns. After evaluating and comparing three constructed financial portfolios, it was found that the RL agent for gradual portfolio rebalancing with the LSTM model outperformed other methods, improving returns by 27.9-93.4% compared to full rebalancing methods.

NEURAL COMPUTING & APPLICATIONS (2022)

Article Computer Science, Artificial Intelligence

Emotionally charged text classification with deep learning and sentiment semantic

Jeow Li Huan, Arif Ahmed Sekh, Chai Quek, Dilip K. Prasad

Summary: This paper investigates text classification methods by using deep models and recurrent neural networks to extract features and represent documents as semantic vector sequences for classification. The addition of sentiment information improves accuracy, outperforming classical techniques in experiments.

NEURAL COMPUTING & APPLICATIONS (2022)

Article Computer Science, Artificial Intelligence

Who are the 'silent spreaders'?: contact tracing in spatio-temporal memory models

Yue Hu, Budhitama Subagdja, Ah-Hwee Tan, Chai Quek, Quanjun Yin

Summary: This paper proposes a neural network model called STEM-COVID to identify asymptomatic COVID-19 cases (ACCs) using contact tracing data. The model incorporates adaptive resonance theory and weighted evidence pooling to achieve high accuracy and efficiency in identifying ACCs. It also demonstrates robustness against noisy data and breakthrough infections after vaccination.

NEURAL COMPUTING & APPLICATIONS (2022)

Article Computer Science, Artificial Intelligence

An embedded deep fuzzy association model for learning and explanation

Xie Chen, Deepu Rajan, Dilip K. Prasad, Chai Quek

Summary: This paper investigates the benefits of using a deep learning model as a fuzzy implication operator in a neuro-fuzzy system for learning and explaining predictions of both steady-state and dynamically changing data. The results show that this approach improves the model performance and enhances the interpretability of the reasoning process.

APPLIED SOFT COMPUTING (2022)

Article Computer Science, Artificial Intelligence

Spike-Timing-Dependent Plasticity With Activation-Dependent Scaling for Receptive Fields Development

Marcin Bialas, Jacek Mandziuk

Summary: This article proposes an effective variant of STDP extended by an activation-dependent scale factor, serving as an efficient mechanism for the unsupervised development of RFs. The importance of synaptic scaling and lateral inhibition in the successful development of RFs is demonstrated, with the significance of maintaining high levels of synaptic scaling highlighted. Experimental results show that the proposed solution performs well in classification tasks on the MNIST dataset.

IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS (2022)

Article Computer Science, Artificial Intelligence

End-to-End Hierarchical Reinforcement Learning With Integrated Subgoal Discovery

Shubham Pateria, Budhitama Subagdja, Ah-Hwee Tan, Chai Quek

Summary: Hierarchical reinforcement learning is an approach to decompose goals into subgoals for long-horizon goal-reaching tasks. End-to-end HRL methods use a hierarchy of policies to search useful subgoals directly in a continuous subgoal space. LIDOSS, an integrated subgoal discovery heuristic, reduces the search space of the higher-level policy by focusing on subgoals with a higher probability of occurrence in state-transition trajectories leading to the goal.

IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS (2022)

Article Computer Science, Artificial Intelligence

Dynamic portfolio rebalancing with lag-optimised trading indicators using SeroFAM and genetic algorithms

Leon Lai Xiang Yeo, Qi Cao, Chai Quek

Summary: This article introduces two trading indicators: the optimized fMACDH indicator and the fMACDH-fRSI indicator. These two indicators are optimized using a genetic algorithm, and the optimized fMACDH indicator is used to propose two rule-based portfolio rebalancing algorithms: Tactical Buy and Hold (TBH) and Rule-Based Business Cycle (RBBC). The experiments show consistent and encouraging performances of these algorithms in dynamic portfolio rebalancing.

EXPERT SYSTEMS WITH APPLICATIONS (2023)

Article Computer Science, Information Systems

VDPC: Variational density peak clustering algorithm

Yizhang Wang, Di Wang, You Zhou, Xiaofeng Zhang, Chai Quek

Summary: The VDPC algorithm is proposed to address the limitation of DPC in identifying clusters with variational density. It systematically performs the clustering task on datasets with different density distributions by identifying representatives, constructing initial clusters, and using a unified clustering framework.

INFORMATION SCIENCES (2023)

Article Computer Science, Artificial Intelligence

Value-Based Subgoal Discovery and Path Planning for Reaching Long-Horizon Goals

Shubham Pateria, Budhitama Subagdja, Ah-Hwee Tan, Chai Quek

Summary: This article proposes a novel subgoal graph-based planning method called LSGVP, which addresses the challenge of learning to reach long-horizon goals in spatial traversal tasks for autonomous agents. LSGVP uses a subgoal discovery heuristic based on cumulative reward and automatically prunes the learned subgoal graph to remove erroneous connections. It achieves higher cumulative positive rewards and goal-reaching success rates compared to other subgoal sampling or discovery heuristics.

IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS (2023)

Article Computer Science, Artificial Intelligence

Spatial-temporal episodic memory modeling for ADLs: encoding, retrieval, and prediction

Xinjing Song, Di Wang, Chai Quek, Ah-Hwee Tan, Yanjiang Wang

Summary: This paper proposes a cognitive model called STEM-ADL, which encodes event sequences to predict the type and starting time of daily self-care activities. Experimental results demonstrate that STEM-ADL outperforms other models and is suitable for real-life healthcare applications.

COMPLEX & INTELLIGENT SYSTEMS (2023)

Article Computer Science, Artificial Intelligence

EEG-Video Emotion-Based Summarization: Learning With EEG Auxiliary Signals

Wai-Cheong Lincoln Lew, Di Wang, Kai Keng Ang, Joo-Hwee Lim, Chai Quek, Ah-Hwee Tan

Summary: This article proposes a video summarization model (EVES) based on EEG and video emotion data, which utilizes multimodal deep reinforcement learning architecture to learn visual interestingness for better video summaries. The experimental results show that EVES outperforms unsupervised models and narrows the performance gap with supervised models. EVES receives higher ratings in content coherency and emotion-evoking content.

IEEE TRANSACTIONS ON AFFECTIVE COMPUTING (2022)

Proceedings Paper Computer Science, Artificial Intelligence

Balancing the Stability-Plasticity Dilemma with Online Stability Tuning for Continual Learning

Anton Lee, Heitor Murilo Gomes, Yaqian Zhang

Summary: Balancing the stability-plasticity trade-off is crucial in continual learning. Instead of using a constant hyper-parameter, we propose a dynamic method to balance stability and plasticity, which has shown improved performance in multiple benchmarks.

2022 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS (IJCNN) (2022)

Article Computer Science, Information Systems

A consensus model considers managing manipulative and overconfident behaviours in large-scale group decision-making

Xia Liang, Jie Guo, Peide Liu

Summary: This paper investigates a novel consensus model based on social networks to manage manipulative and overconfident behaviors in large-scale group decision-making. By proposing a novel clustering model and improved methods, the consensus reaching is effectively facilitated. The feedback mechanism and management approach are employed to handle decision makers' behaviors. Simulation experiments and comparative analysis demonstrate the effectiveness of the model.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

CGN: Class gradient network for the construction of adversarial samples

Xiang Li, Haiwang Guo, Xinyang Deng, Wen Jiang

Summary: This paper proposes a method based on class gradient networks for generating high-quality adversarial samples. By introducing a high-level class gradient matrix and combining classification loss and perturbation loss, the method demonstrates superiority in the transferability of adversarial samples on targeted attacks.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Distinguishing latent interaction types from implicit feedbacks for recommendation

Lingyun Lu, Bang Wang, Zizhuo Zhang, Shenghao Liu

Summary: Many recommendation algorithms only rely on implicit feedbacks due to privacy concerns. However, the encoding of interaction types is often ignored. This paper proposes a relation-aware neural model that classifies implicit feedbacks by encoding edges, thereby enhancing recommendation performance.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Proximity-based density description with regularized reconstruction algorithm for anomaly detection

Jaehong Yu, Hyungrok Do

Summary: This study discusses unsupervised anomaly detection using one-class classification, which determines whether a new instance belongs to the target class by constructing a decision boundary. The proposed method uses a proximity-based density description and a regularized reconstruction algorithm to overcome the limitations of existing one-class classification methods. Experimental results demonstrate the superior performance of the proposed algorithm.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Non-iterative border-peeling clustering algorithm based on swap strategy

Hui Tu, Shifei Ding, Xiao Xu, Haiwei Hou, Chao Li, Ling Ding

Summary: Border-Peeling algorithm is a density-based clustering algorithm, but its complexity and issues on unbalanced datasets restrict its application. This paper proposes a non-iterative border-peeling clustering algorithm, which improves the clustering performance by distinguishing and associating core points and border points.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

A two-stage denoising framework for zero-shot learning with noisy labels

Long Tang, Pan Zhao, Zhigeng Pan, Xingxing Duan, Panos M. Pardalos

Summary: In this work, a two-stage denoising framework (TSDF) is proposed for zero-shot learning (ZSL) to address the issue of noisy labels. The framework includes a tailored loss function to remove suspected noisy-label instances and a ramp-style loss function to reduce the negative impact of remaining noisy labels. In addition, a dynamic screening strategy (DSS) is developed to efficiently handle the nonconvexity of the ramp-style loss.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Selection of a viable blockchain service provider for data management within the internet of medical things: An MCDM approach to Indian healthcare

Raghunathan Krishankumar, Sundararajan Dhruva, Kattur S. Ravichandran, Samarjit Kar

Summary: Health 4.0 is gaining global attention for better healthcare through digital technologies. This study proposes a new decision-making framework for selecting viable blockchain service providers in the Internet of Medical Things (IoMT). The framework addresses the limitations in previous studies and demonstrates its applicability in the Indian healthcare sector. The results show the top ranking BSPs, the importance of various criteria, and the effectiveness of the developed model.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Q-learning with heterogeneous update strategy

Tao Tan, Hong Xie, Liang Feng

Summary: This paper proposes a heterogeneous update idea and designs HetUp Q-learning algorithm to enlarge the normalized gap by overestimating the Q-value corresponding to the optimal action and underestimating the Q-value corresponding to the other actions. To address the limitation, a softmax strategy is applied to estimate the optimal action, resulting in HetUpSoft Q-learning and HetUpSoft DQN. Extensive experimental results show significant improvements over SOTA baselines.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Dyformer: A dynamic transformer-based architecture for multivariate time series classification

Chao Yang, Xianzhi Wang, Lina Yao, Guodong Long, Guandong Xu

Summary: This paper proposes a dynamic transformer-based architecture called Dyformer for multivariate time series classification. Dyformer captures multi-scale features through hierarchical pooling and adaptive learning strategies, and improves model performance by introducing feature-map-wise attention mechanisms and a joint loss function.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

ESSENT: an arithmetic optimization algorithm with enhanced scatter search strategy for automated test case generation

Xiguang Li, Baolu Feng, Yunhe Sun, Ammar Hawbani, Saeed Hammod Alsamhi, Liang Zhao

Summary: This paper proposes an enhanced scatter search strategy, using opposition-based learning, to solve the problem of automated test case generation based on path coverage (ATCG-PC). The proposed ESSENT algorithm selects the path with the lowest path entropy among the uncovered paths as the target path and generates new test cases to cover the target path by modifying the dimensions of existing test cases. Experimental results show that the ESSENT algorithm outperforms other state-of-the-art algorithms, achieving maximum path coverage with fewer test cases.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

An attention based approach for automated account linkage in federated identity management

Shirin Dabbaghi Varnosfaderani, Piotr Kasprzak, Aytaj Badirova, Ralph Krimmel, Christof Pohl, Ramin Yahyapour

Summary: Linking digital accounts belonging to the same user is crucial for security, user satisfaction, and next-generation service development. However, research on account linkage is mainly focused on social networks, and there is a lack of studies in other domains. To address this, we propose SmartSSO, a framework that automates the account linkage process by analyzing user routines and behavior during login processes. Our experiments on a large dataset show that SmartSSO achieves over 98% accuracy in hit-precision.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

A memetic algorithm with fuzzy-based population control for the joint order batching and picker routing problem

Renchao Wu, Jianjun He, Xin Li, Zuguo Chen

Summary: This paper proposes a memetic algorithm with fuzzy-based population control (MA-FPC) to solve the joint order batching and picker routing problem (JOBPRP). The algorithm incorporates batch exchange crossover and a two-level local improvement procedure. Experimental results show that MA-FPC outperforms existing algorithms in terms of solution quality.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

Refining one-class representation: A unified transformer for unsupervised time-series anomaly detection

Guoxiang Zhong, Fagui Liu, Jun Jiang, Bin Wang, C. L. Philip Chen

Summary: In this study, we propose the AMFormer framework to address the problem of mixed normal and anomaly samples in deep unsupervised time-series anomaly detection. By refining the one-class representation and introducing the masked operation mechanism and cost sensitive learning theory, our approach significantly improves anomaly detection performance.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

A data-driven optimisation method for a class of problems with redundant variables and indefinite objective functions

Jin Zhou, Kang Zhou, Gexiang Zhang, Ferrante Neri, Wangyang Shen, Weiping Jin

Summary: In this paper, the authors focus on the issue of multi-objective optimisation problems with redundant variables and indefinite objective functions (MOPRVIF) in practical problem-solving. They propose a dual data-driven method for solving this problem, which consists of eliminating redundant variables, constructing objective functions, selecting evolution operators, and using a multi-objective evolutionary algorithm. The experiments conducted on two different problem domains demonstrate the effectiveness, practicality, and scalability of the proposed method.

INFORMATION SCIENCES (2024)

Article Computer Science, Information Systems

A Monte Carlo fuzzy logistic regression framework against imbalance and separation

Georgios Charizanos, Haydar Demirhan, Duygu Icen

Summary: This article proposes a new fuzzy logistic regression framework that addresses the problems of separation and imbalance while maintaining the interpretability of classical logistic regression. By fuzzifying binary variables and classifying subjects based on a fuzzy threshold, the framework demonstrates superior performance on imbalanced datasets.

INFORMATION SCIENCES (2024)