Several clustering methods (e.g., Normalized Cut and Ratio Cut) divide the Min Cut cost function by a cluster dependent factor (e.g., the size or the degree of the clusters), in order to yield a more balanced partitioning. We, instead, investigate adding such regularizations to the original cost function. We first consider the case where the regularization term is the sum of the squared size of the clusters, and then generalize it to adaptive regularization of the pairwise similarities. This leads to shifting (adaptively) the pairwise similarities which might make some of them negative. We then study the connection of this method to Correlation Clustering and then propose an efficient local search optimization algorithm with fast theoretical convergence rate to solve the new clustering problem. In the following, we investigate the shift of pairwise similarities on some common clustering methods, and finally, we demonstrate the superior performance of the method by extensive experiments on different datasets.

We propose unsupervised representation learning and feature extraction from dendrograms. The commonly used Minimax distance measures correspond to building a dendrogram with single linkage criterion, with defining specific forms of a level function and a distance function over that. Therefore, we extend this method to arbitrary dendrograms. We develop a generalized framework wherein different distance measures and representations can be inferred from different types of dendrograms, level functions and distance functions. Via an appropriate embedding, we compute a vector-based representation of the inferred distances, in order to enable many numerical machine learning algorithms to employ such distances. Then, to address the model selection problem, we study the aggregation of different dendrogram-based distances respectively in solution space and in representation space in the spirit of deep representations. In the first approach, for example for the clustering problem, we build a graph with positive and negative edge weights according to the consistency of the clustering labels of different objects among different solutions, in the context of ensemble methods. Then, we use an efficient variant of correlation clustering to produce the final clusters. In the second approach, we investigate the combination of different distances and features sequentially in the spirit of multi-layered architectures to obtain the final features. Finally, we demonstrate the effectiveness of our approach via several numerical studies.

Standard agglomerative clustering suggests establishing a new reliable linkage at every step. However, in order to provide adaptive, density-consistent and flexible solutions, we study extracting all the reliable linkages at each step, instead of the smallest one. Such a strategy can be applied with all common criteria for agglomerative hierarchical clustering. We also study that this strategy with the single linkage criterion yields a minimum spanning tree algorithm. We perform experiments on several real-world datasets to demonstrate the performance of this strategy compared to the standard alternative.

We investigate the use of Minimax distances to extract in a nonparametric way the features that capture the unknown underlying patterns and structures in the data. We develop a general-purpose and computationally efficient framework to employ Minimax distances with many machine learning methods that perform on numerical data. We study both computing the pairwise Minimax distances for all pairs of objects and as well as computing the Minimax distances of all the objects to/from a fixed (test) object. We first efficiently compute the pairwise Minimax distances between the objects, using the equivalence of Minimax distances over a graph and over a minimum spanning tree constructed on that. Then, we perform an embedding of the pairwise Minimax distances into a new vector space, such that their squared Euclidean distances in the new space equal to the pairwise Minimax distances in the original space. We also study the case of having multiple pairwise Minimax matrices, instead of a single one. Thereby, we propose an embedding via first summing up the centered matrices and then performing an eigenvalue decomposition to obtain the relevant features. In the following, we study computing Minimax distances from a fixed (test) object which can be used for instance in K-nearest neighbor search. Similar to the case of all-pair pairwise Minimax distances, we develop an efficient and general-purpose algorithm that is applicable with any arbitrary base distance measure. Moreover, we investigate in detail the edges selected by the Minimax distances and thereby explore the ability of Minimax distances in detecting outlier objects. Finally, for each setting, we perform several experiments to demonstrate the effectiveness of our framework.

We review clustering as an analysis tool and the underlying concepts from an introductory perspective. What is clustering and how can clusterings be realised programmatically? How can data be represented and prepared for a clustering task? And how can clustering results be validated? Connectivity-based versus prototype-based approaches are reflected in the context of several popular methods: single-linkage, spectral embedding, k-means, and Gaussian mixtures are discussed as well as the density-based protocols (H)DBSCAN, Jarvis-Patrick, CommonNN, and density-peaks.

We study Frank-Wolfe algorithms - standard, pairwise, and away-steps - for efficient optimization of Dominant Set Clustering. We present a unified and computationally efficient framework to employ the different variants of Frank-Wolfe methods, and we investigate its effectiveness via several experimental studies. In addition, we provide explicit convergence rates for the algorithms in terms of the so-called Frank-Wolfe gap. The theoretical analysis has been specialized to Dominant Set Clustering and covers consistently the different variants.

群集集群或共识群集已成为一种强大的工具，用于提高各种聚类方法的鲁棒性和结果的稳定性。加权聚类集群自然地从集群集群中产生。加权群集集合的参数之一是聚类集群中的元素（群集或集群）具有不同的质量，或者对象或特征具有不同意义的重要性。但是，不可能直接将加权机制从分类（监督）域中应用于群集（无监督）域，因为群集本质上是一个不存在的问题。本文通过讨论不同类型的权重，确定重量值的主要方法以及将加权聚类集合与复杂数据的应用程序的主要方法概述了加权集群集群集合概述。本文提出的统一框架将有助于聚类从业者为自己的问题选择最合适的加权机制。

Graph clustering is a fundamental problem in unsupervised learning, with numerous applications in computer science and in analysing real-world data. In many real-world applications, we find that the clusters have a significant high-level structure. This is often overlooked in the design and analysis of graph clustering algorithms which make strong simplifying assumptions about the structure of the graph. This thesis addresses the natural question of whether the structure of clusters can be learned efficiently and describes four new algorithmic results for learning such structure in graphs and hypergraphs. All of the presented theoretical results are extensively evaluated on both synthetic and real-word datasets of different domains, including image classification and segmentation, migration networks, co-authorship networks, and natural language processing. These experimental results demonstrate that the newly developed algorithms are practical, effective, and immediately applicable for learning the structure of clusters in real-world data.

由于其数值益处增加及其坚实的数学背景，光谱聚类方法的非线性重构近来的关注。我们在$ p $ -norm中提出了一种新的直接多道谱聚类算法，以$ p \ in（1,2] $。计算图表的多个特征向量的问题$ p $ -laplacian，标准的非线性概括Graph Laplacian，被重用作为Grassmann歧管的无约束最小化问题。$ P $的价值以伪连续的方式减少，促进对应于最佳图形的稀疏解决方案载体作为$ P $接近。监测单调减少平衡图削减了我们从$ P $ -Levels获得的最佳可用解决方案的保证。我们展示了我们算法在各种人工测试案件中的算法的有效性和准确性。我们的数值和比较结果具有各种状态-Art聚类方法表明，所提出的方法在均衡的图形剪切度量和标签分配的准确性方面取得高质量的集群。此外，我们进行S面部图像和手写字符分类的束缚，以展示现实数据集中的适用性。

In recent years, spectral clustering has become one of the most popular modern clustering algorithms. It is simple to implement, can be solved efficiently by standard linear algebra software, and very often outperforms traditional clustering algorithms such as the k-means algorithm. On the first glance spectral clustering appears slightly mysterious, and it is not obvious to see why it works at all and what it really does. The goal of this tutorial is to give some intuition on those questions. We describe different graph Laplacians and their basic properties, present the most common spectral clustering algorithms, and derive those algorithms from scratch by several different approaches. Advantages and disadvantages of the different spectral clustering algorithms are discussed.

近年来，在平衡（超级）图分配算法的设计和评估中取得了重大进展。我们调查了过去十年的实用算法的趋势，用于平衡（超级）图形分区以及未来的研究方向。我们的工作是对先前有关该主题的调查的更新。特别是，该调查还通过涵盖了超图形分区和流算法来扩展先前的调查，并额外关注并行算法。

在本文中，我们提出了一种新方法来检测具有归因顶点的无向图中的簇。目的是将不仅在结构连接性方面，而且在属性值方面相似的顶点分组。我们通过创建[6,38]中提出的其他顶点和边缘，将顶点之间的结构和属性相似。然后将增强图嵌入到与其拉普拉斯式相关的欧几里得空间中，在该空间中，应用了修改的K-均值算法以识别簇。修改后的k均值依赖于矢量距离度量，根据每个原始顶点，我们分配了合适的矢量值坐标集，这取决于结构连接性和属性相似性，因此每个原始图顶点都被认为是$ M+1的代表增强图的$顶点，如果$ m $是顶点属性的数量。为了定义坐标矢量，我们基于自适应AMG（代数多机）方法采用了我们最近提出的算法，该方法识别了嵌入欧几里得空间中的坐标方向，以代数平滑的矢量相对于我们的增强图Laplacian，从而扩展了laplacian，从而扩展了坐标。没有属性的图形的先前结果。我们通过与一些知名方法进行比较，分析了我们提出的聚类方法的有效性，这些方法可以免费获得软件实现，并与文献中报告的结果相比，在两种不同类型的广泛使用的合成图上以及在某些现实世界中的图形上。

在过去十年中，图形内核引起了很多关注，并在结构化数据上发展成为一种快速发展的学习分支。在过去的20年中，该领域发生的相当大的研究活动导致开发数十个图形内核，每个图形内核都对焦于图形的特定结构性质。图形内核已成功地成功地在广泛的域中，从社交网络到生物信息学。本调查的目标是提供图形内核的文献的统一视图。特别是，我们概述了各种图形内核。此外，我们对公共数据集的几个内核进行了实验评估，并提供了比较研究。最后，我们讨论图形内核的关键应用，并概述了一些仍有待解决的挑战。

我们启动了一项全面的实验研究，对大量数据集的基于目标的层次聚类方法，该方法包括来自计算机视觉和NLP应用程序的深层嵌入向量。这包括各种各样的图像嵌入（Imagenet，ImagenetV2，nabirds），单词嵌入（Twitter，Wikipedia）和句子嵌入（SST-2）载体（例如，Resnet，Resnext，Insnext，Inception V3，Sbert，Sbert）中的句子嵌入（SST-2）矢量。我们的研究包括最高45万美元的条目的数据集，其嵌入式尺寸高达2048美元。为了解决将层次聚类扩展到如此大的数据集的挑战，我们提出了一种新的实用层次聚类算法B ++＆c。流行的Moseley-Wang（MW） / Cohen-Addad等人的平均可获得5％ / 20％的提高。 （CKMM）目标（归一化）与广泛的经典方法和最近的启发式方法相比。我们还引入了一种理论算法B2SAT＆C，该算法在多项式时间内实现了CKMM目标的0.74 $ approximation。这是对随机二进制树实现的微不足道$ 2/3 $ - approximation的首次实质性改进。在这项工作之前，$ \ $ \ 2/3 + 0.0004 $的最佳聚时近似是由于Charikar等人。 （Soda'19）。

比较图形等结构的对象是许多学习任务中涉及的基本操作。为此，基于最优传输（OT）的Gromov-Wasserstein（GW）距离已被证明可以成功处理相关对象的特定性质。更具体地说，通过节点连接关系，GW在图表上运行，视为特定空间上的概率测量。在OT的核心处是质量守恒的想法，这在两个被认为的图表中的所有节点之间施加了耦合。我们在本文中争辩说，这种财产可能对图形字典或分区学习等任务有害，我们通过提出新的半轻松的Gromov-Wasserstein发散来放松它。除了立即计算福利之外，我们讨论其属性，并表明它可以导致有效的图表字典学习算法。我们经验展示其对图形上的复杂任务的相关性，例如分区，聚类和完成。

最小的平方和群集（MSSC）或K-Means型聚类，传统上被认为是无监督的学习任务。近年来，使用背景知识来提高集群质量，促进聚类过程的可解释性已成为数学优化和机器学习研究的热门研究课题。利用数据群集中的背景信息的问题称为半监督或约束群集。在本文中，我们为半监控MSSC提供了一种新的分支和绑定算法，其中背景知识被包含为成对必须 - 链接和无法链接约束。对于较低的界限，我们解决了MSSC离散优化模型的Semidefinite编程宽松，并使用了用于加强界限的纤维平面程序。相反，通过使用整数编程工具，我们提出了将K-Means算法适应受约束的情况。这是第一次，所提出的全局优化算法有效地管理，以解决现实世界的情况，最高可达800个数据点，具有必要的必须 - 链接和无法链接约束以及通用数量的功能。这个问题大小大约比最先进的精确算法解决的实例大约四倍。

在本文中，我们提出了一种与成对约束聚类的主动度量学习方法。该方法主动查询信息性实例对的标签，同时通过结合未标记的实例对估计底层度量，这导致更准确和有效的聚类过程。特别是，我们通过生成更多成对标签来增强查询的约束，以提供学习度量标准以增强聚类性能的附加信息。此外，我们通过顺序更新学习的度量并自适应地惩罚无关的特征来增加度量学习的鲁棒性。此外，我们提出了一种新的主​​动查询策略，通过结合邻域结构来更准确地评估实例对的信息增益，这提高了集群效率而无需额外的标记成本。理论上，我们提供了利用使用现有约束的方法使用增强查询的所提出的度量学习方法的更紧密的错误。此外，我们还使用主动查询策略而不是随机选择来研究改进。仿真设置和实际数据集的数值研究表明，当显着特征和无关的特征之间的信噪比低时，所提出的方法是特别有利的。

Originally, tangles were invented as an abstract tool in mathematical graph theory to prove the famous graph minor theorem. In this paper, we showcase the practical potential of tangles in machine learning applications. Given a collection of cuts of any dataset, tangles aggregate these cuts to point in the direction of a dense structure. As a result, a cluster is softly characterized by a set of consistent pointers. This highly flexible approach can solve clustering problems in various setups, ranging from questionnaires over community detection in graphs to clustering points in metric spaces. The output of our proposed framework is hierarchical and induces the notion of a soft dendrogram, which can help explore the cluster structure of a dataset. The computational complexity of aggregating the cuts is linear in the number of data points. Thus the bottleneck of the tangle approach is to generate the cuts, for which simple and fast algorithms form a sufficient basis. In our paper we construct the algorithmic framework for clustering with tangles, prove theoretical guarantees in various settings, and provide extensive simulations and use cases. Python code is available on github.

我们讨论集群分析的拓扑方面，并表明在聚类之前推断数据集的拓扑结构可以大大增强群集检测：理论论证和经验证据表明，聚类嵌入向量，代表数据歧管的结构，而不是观察到的特征矢量他们自己是非常有益的。为了证明，我们将流形学习方法与基于密度的聚类方法DBSCAN结合了歧管学习方法UMAP。合成和真实数据结果表明，这既简化和改善了多种低维问题，包括密度变化和/或纠缠形状的群集。我们的方法简化了聚类，因为拓扑预处理始终降低DBSCAN的参数灵敏度。然后，用dbscan聚类所得的嵌入可以超过诸如spectacl和clustergan之类的复杂方法。最后，我们的调查表明，聚类中的关键问题似乎不是数据的标称维度或其中包含多少不相关的功能，而是\ textIt {可分离}群集在环境观察空间中的\ textit {可分离}，它们嵌入了它们中。 ，通常是数据特征定义的（高维）欧几里得空间。我们的方法之所以成功，是因为我们将数据投影到更合适的空间后，从某种意义上说，我们执行了群集分析。

我们介绍了一个新型的多层加权网络模型，该模型除了本地信号外，还考虑了全局噪声。该模型类似于多层随机块模型（SBM），但关键区别在于，跨层之间的块之间的相互作用在整个系统中是常见的，我们称之为环境噪声。单个块还以这些固定的环境参数为特征，以表示不属于其他任何地方的成员。这种方法允许将块同时聚类和类型化到信号或噪声中，以便更好地理解其在整个系统中的作用，而现有块模型未考虑。我们采用了分层变异推断的新颖应用来共同检测和区分块类型。我们称此模型为多层加权网络称为随机块（具有）环境噪声模型（SBANM），并开发了相关的社区检测算法。我们将此方法应用于费城神经发育队列中的受试者，以发现与精神病有关的具有共同心理病理学的受试者社区。