An Efficient Algorithm for Clustering Short Spoken Utterances

The data-classification process can possibly involve a huge amount of data in today's cloud computing environment. It could take a long time for processing, and could consume many resources for computation and storage. This study focuses on the problem of using the traditional hierarchical agglomerative clustering algorithm on a distributed environment since hierarchical agglomerative clustering has high applicability and efficiency. A parallel hierarchical ag-glomerative clustering algorithm is proposed in this study. The proposed algorithm divides the whole computation into several small tasks, distribute the tasks to message-passing processes, and merge the results to form a hierarchical cluster. A threshold is used to reduce the storage requirement during the computation. To evaluate the performance and limitation of our algorithm, this study has conducted several experiments using real astronomical data, the main asteroid belt catalog. The experimental results confirm that the proposed parallel algorithm is efficient.

Classifying an unknown object in image retrieval systems using the nearest neighbour classifier would be very time consuming when the number of the objects within the associated database is high. Generating a dendrogram using a Hierarchical Agglomerative Clustering (HAC) algorithm and searching the database images from coarse to fine resolutions using image pyramids are two important groups of techniques widely used for dealing with this problem. In this paper, a novel algorithm is proposed by combining these methods within the framework of a face recognition system. The search process is performed in a coarse-to-fine manner using image pyramids. On the bottom level of the pyramid (the finest resolution), a set of dendrograms is formed using the HAC algorithm. Our experimental studies show that the recognition process can be speeded up by a factor of around 65 compare to the basic nearest neighbour classifier. In such a condition, however, the recognition rate is slightly reduced.

The authors show that most hierarchical agglomerative clustering (HAC) algorithms follow a 90-10 rule where roughly 90% iterations from the beginning merge cluster pairs with dissimilarity less than 10% of the maximum dissimilarity. We propose two algorithms: 2-phase and nested, based on partially overlapping partitioning (POP). To handle high-dimensional data efficiently, we propose a tree structure particularly suitable for POP. Extensive experiments show that the proposed algorithms reduce the time and memory requirement of existing HAC algorithms significantly without compromising accuracy.

In this paper we study the use of a semi-supervised agglomerative hierarchical clustering (ssAHC) algorithm to text categorization, which consists of assigning text documents to predefined categories. ssAHC is (i) a clustering algorithm that (ii) uses a finite design set of labeled data to (iii) help agglomerative hierarchical clustering (AHC) algorithms partition a finite set of unlabeled data and then (iv) terminates without the capability to label other objects. We first describe the text representation method we use in this work; we then present a feature selection method that is used to reduce the dimensionality of the feature space. Finally, we apply the ssAHC algorithm to the Reuters database of documents and show that its performance is superior to the Bayes classifier and to the Expectation-Maximization algorithm combined with Bayes classifier. We showed also that ssAHC helps AHC techniques to improve their performance. © 2000 John Wiley & Sons, Inc.

Reducing package‐related cost is essential for various companies and institutions. Different packages are usually designed separately for each and every product, which results in less cost‐effective packaging systems. In this study, a data mining model with three clustering algorithms was developed to modularize a packaging system by reducing the variety of packaging sizes. The three algorithms were k‐means clustering, agglomerative hierarchical clustering and self‐organizing feature map. The package models with similar shapes and sizes were clustered automatically and replaced by one package model with a size that suited them all. The study also analysed the financial effects including the purchasing and inventory costs of the package material and the transportation cost of the packaged products. The case study was carried out at Ericsson to select the best clustering algorithm of the three and to test the effectiveness and applicability of the proposed model. The results show that the packaging system modularized by the agglomerative hierarchical clustering algorithm is more cost‐effective in this case compared with the ones modularized by the other two clustering algorithms and with the one without modularization. Copyright © 2017 John Wiley & Sons, Ltd.

This work aims to expand the knowledge of the area of data analysis through persistence homology and representations of directed graphs. To be specific, we looked for how we can analyze homology cluster groups using agglomerative Hierarchical Clustering algorithms and methods. Additionally, the Wine data, which is offered in R studio, was analyzed using various cluster algorithms such as Hierarchical Clustering, K-Means Clustering, and PAM Clustering. The goal of the analysis was to find out which cluster's method is proper for a given numerical dataset. We tried to find the agglomerative hierarchical clustering method by testing the data that will be the optimal clustering algorithm among these three; K-Means, PAM, and Random Forest methods. By comparing each model's accuracy value with cultivar coefficients, we concluded that K-Means methods are the most helpful when working with numerical variables. On the other hand, PAM clustering and Gower with Random Forest are the most beneficial approaches when using categorical variables. These tests can determine the optimal number of clustering groups, given the data set, and by doing the proper analysis. Using those the project, we can apply our method to several industrial areas such that clinical, business, and others. For example, people can make different groups based on each patient who has a common disease, required therapy, and other things in the clinical society. Additionally, people can expect to get several clustered groups based on the marginal profit, marginal cost, or other economic indicators for the business area.

To solve name ambiguity problems and improve the performance of person name disambiguation, we propose a three-stage clustering algorithm in the paper. In the first stage, organizations and locations (OLs) are used to cluster documents about the same person, therefore some texts with more resemblance will be assigned to one category. This stage is simply document clustering based on the similarity of OLs. In the second stage, the clustered documents are used as a new data source from which some novel features (like co-author names) are extracted. We used these new extracted features to make additional clustering between documents. Meanwhile, a method was proposed to solve name ambiguity problems by using social networks construction based on the relationships among co-authors. In the third stage, Web pages are further clustered using content-based hierarchical agglomerative clustering (HAC) algorithm, then analyzing the useful content including title and abstract and keywords (TAKs) to disambiguate the ambiguous names. Experimental results show that our three-stage clustering algorithm can availably enhance the performance of person name disambiguation.

The security and integrity of a computer system is compromised when an intrusion occurs. It becomes impossible for legitimate users to access different network services when network-based attacks purposely occupy or sabotage network resources and services. Our proposed method is a scalable detection method for network based anomalies. We use Support Vector Machines (SVM) for classification. This paper presents a method for enhancing the training time of SVM, particularly when dealing with large data sets, using hierarchical clustering technique. We use the Dynamically Growing Self-Organizing Tree (DGSOT) algorithm for clustering because it has proved to overcome the problems of traditional hierarchical clustering algorithms (e.g., hierarchical agglomerative clustering). Clustering analysis helps to find the boundary points, which are the most qualified data points to train SVM, between any two classes. We present a new approach of combination of SVM and DGSOT, which begins with an initial training set and expands it gradually using the clustering structure produced by the DGSOT algorithm. We show that our proposed variations contribute significantly in improving the training process of SVM with high percentage of detection accuracy. Keywords: SVM, classification, Intrusion detection, Intrusion detection System, Network Security

The automatic or semi-automatic construction of ontology has become a research topic of interest in recent years. This paper describes a mechanism for constructing domain specific ontologies automatically based on web data and generic ontology. Firstly, we employ the hierarchical agglomerative clustering(HAC) algorithm, clustering web pages hierarchically and resulting in a binary tree. Then an algorithm is proposed, which selectd from the binary tree the significative nodes as topics implying concepts of domain interests. Lastly, the Chinese generic ontology, HowNet, is introduced to evolve the topics (together with their hierarchical structures) into domain ontology. We experiment our method in the field of computer hardware based on web pages collected from Chinese BtoC web sites. An in-depth discussion on the experiment results is also given.

Customer segmentation plays an important role in customer relationship management. It allows companies to design and establish different strategies to maximize the value of customers. Customer segmentation refers to grouping customers into different categories based on shared characteristics such as age, location, spending habit and so on. Similarly, clustering means putting things together in such a way that similar type of things remain in the same group. In this study, a machine learning (ML) hierarchical agglomerative clustering (HAC) algorithm is implemented in the R programming language to perform customer segmentation on credit card data sets to determine the appropriate marketing strategies.

The study analysed salesmen itinerary of a confectionery supplier in Indonesia. Channel management and robust product distribution are important elements for confectionery business, since growth heavily depends on healthy product distribution. To support product distribution, optimising salesmen itinerary plays an important role in the firm's sales operation. The study was limited to optimising salesmen schedule for its wholesalers' outlet type, since it contributed to 78% of its revenue. The analyses were carried out using 'cluster first-route second' approach. For clustering the customer nodes, it recommended agglomerative hierarchical clustering (AHC) method. For routing within each customer's cluster, it tested two algorithms, i.e., Clarke-Wright and weighted-serving time-visual approach. The result showed that AHC-weighted-serving-time-visual algorithm was as good as AHC-Clarke-Wright with 2.1% cheaper variable cost. The proposed algorithm was adapted from practical insight and easier to be understood.

Regionalization of watersheds by hybrid-cluster analysis

Hybrid precoding design can be challenging for broadband millimeter-wave (mmWave) massive MIMO due to the frequency-flat analog precoder in radio frequency (RF). Prior broadband hybrid precoding work usually focuses on fully-connected array (FCA), while seldom considers the energy-efficient partially-connected subarray (PCS) including the fixed subarray (FS) and dynamic subarray (DS). Against this background, this paper proposes a machine learning based broadband hybrid precoding for mmWave massive MIMO with DS. Specifically, we first propose an optimal hybrid precoder based on principal component analysis (PCA) for the FS, whereby the frequency-flat RF precoder for each subarray is extracted from the principle component of the optimal frequency-selective precoders for fully-digital MIMO. Moreover, we extend the PCA-based hybrid precoding to DS, where a shared agglomerative hierarchical clustering (AHC) algorithm developed from machine learning is proposed to group the DS for improved spectral efficiency (SE). Finally, we investigate the energy efficiency (EE) of the proposed scheme for both passive and active antennas. Simulations have confirmed that the proposed scheme outperforms conventional schemes in both SE and EE.

The accuracy of existing hierarchical clustering algorithms in distance measurement is not high, in order to improve it, this paper proposes a condensing hierarchical clustering algorithm based on global distance measurement. This method puts forward the concept of global distance and local distance for the distance measurement, effectively depicting the distance between the data objects, in the merger of the clusters, it also proposes two new concepts: the cohesion within the class and the separability between classes, at the same time, on the basis of these two concepts, it constructs an objective function and maximizes the objective function to reach the purpose that the cohesion within the class be as large as possible, the separability between classes be as small as possible, in order to obtain the optimal clustering results. The experimental accuracy of this algorithm is higher than traditional hierarchical clustering algorithms both on the artificial data and real data sets, which shows that the algorithm has higher clustering validity.

The proliferation of big data and the growth of e-commerce have intensified the challenges associated with extracting actionable data for personalised recommendations and decision-making. With data-driven marketing strategies, understanding and predicting customer behaviour has become paramount for maintaining competitive advantage. This study leverages business analytics tools, focusing on Recency, Frequency, and Monetary (RFM) Analysis, alongside K-Means and Hierarchical (Agglomerative) Clustering algorithms, to segment customer transactional data. Data normalisation, a critical step for accurate clustering, was performed using log transformation and the Power Transformer technique with the Yeo-Johnson parameter, the latter proving more effective for handling both positively and negatively skewed data, enhancing data normalisation and suitability for analysis. This study reveals that RFM Analysis with Hierarchical Clustering outperforms K-Means Clustering, achieving a Silhouette Score of 0.47 and a Calinski–Harabasz Index of 3787.1, indicating a more accurate identification of customer segments. RFM Analysis alone generated eight clusters, while integrating RFM Analysis with both Hierarchical Clustering and K-Means generated three similar-sized clusters with interchanged labels. These metrics highlight the proficiency of Hierarchical Clustering in identifying unique customer segments and customising marketing strategies. The findings indicate that the RFM-Hierarchical Clustering approach enhances segmentation precision and facilitates more refined and effective marketing strategies.