Clustering
Agglomerative Multivariate Information Bottleneck
Slonim, Noam, Friedman, Nir, Tishby, Naftali
The information bottleneck method is an unsupervised model independent data organization technique. Given a joint distribution peA, B), this method constructs anew variable T that extracts partitions, or clusters, over the values of A that are informative about B. In a recent paper, we introduced a general principled frameworkfor multivariate extensions of the information bottleneck method that allows us to consider multiple systems of data partitions that are interrelated. In this paper, we present a new family of simple agglomerative algorithms to construct such systems of interrelated clusters. We analyze the behavior of these algorithms and apply them to several real-life datasets.
An Efficient Clustering Algorithm Using Stochastic Association Model and Its Implementation Using Nanostructures
Morie, Takashi, Matsuura, Tomohiro, Nagata, Makoto, Iwata, Atsushi
This paper describes a clustering algorithm for vector quantizers using a "stochastic association model". It offers a new simple and powerful softmax adaptationrule. The adaptation process is the same as the online K-means clustering method except for adding random fluctuation in the distortion error evaluation process. Simulation results demonstrate that the new algorithm can achieve efficient adaptation as high as the "neural gas" algorithm, which is reported as one of the most efficient clustering methods. It is a key to add uncorrelated random fluctuation in the similarity evaluationprocess for each reference vector. For hardware implementation ofthis process, we propose a nanostructure, whose operation is described by a single-electron circuit. It positively uses fluctuation in quantum mechanical tunneling processes.
On Spectral Clustering: Analysis and an algorithm
Ng, Andrew Y., Jordan, Michael I., Weiss, Yair
First, there are a wide variety of algorithms that use the eigenvectors in slightly different ways. Second, many of these algorithms have no proof that they will actually compute a reasonable clustering. In this paper, we present a simple spectral clustering algorithm that can be implemented using a few lines of Matlab. Using tools from matrix perturbation theory, we analyze the algorithm, and give conditions under which it can be expected to do well. We also show surprisingly good experimental results on a number of challenging clustering problems.
Iterative Double Clustering for Unsupervised and Semi-Supervised Learning
El-Yaniv, Ran, Souroujon, Oren
We present a powerful meta-clustering technique called Iterative Double Clustering(IDC). The IDC method is a natural extension of the recent Double Clustering (DC) method of Slonim and Tishby that exhibited impressiveperformance on text categorization tasks [12]. Using synthetically generated data we empirically find that whenever the DC procedure is successful in recovering some of the structure hidden in the data, the extended IDC procedure can incrementally compute a significantly more accurate classification. IDC is especially advantageous whenthe data exhibits high attribute noise. Our simulation results also show the effectiveness of IDC in text categorization problems. Surprisingly,this unsupervised procedure can be competitive with a (supervised) SVM trained with a small training set. Finally, we propose a simple and natural extension of IDC for semi-supervised and transductive learning where we are given both labeled and unlabeled examples.
Probabilistic Abstraction Hierarchies
Segal, Eran, Koller, Daphne, Ormoneit, Dirk
Many domains are naturally organized in an abstraction hierarchy or taxonomy, where the instances in "nearby" classes in the taxonomy are similar. In this paper, weprovide a general probabilistic framework for clustering data into a set of classes organized as a taxonomy, where each class is associated with a probabilistic modelfrom which the data was generated. The clustering algorithm simultaneously optimizes three things: the assignment of data instances to clusters, themodels associated with the clusters, and the structure of the abstraction hierarchy. A unique feature of our approach is that it utilizes global optimization algorithms for both of the last two steps, reducing the sensitivity to noise and the propensity to local maxima that are characteristic of algorithms such as hierarchical agglomerativeclustering that only take local steps. We provide a theoretical analysis for our algorithm, showing that it converges to a local maximum of the joint likelihood of model and data.
The Method of Quantum Clustering
We propose a novel clustering method that is an extension of ideas inherent toscale-space clustering and support-vector clustering. Like the latter, itassociates every data point with a vector in Hilbert space, and like the former it puts emphasis on their total sum, that is equal to the scalespace probabilityfunction. The novelty of our approach is the study of an operator in Hilbert space, represented by the Schrรถdinger equation of which the probability function is a solution. This Schrรถdinger equation contains a potential function that can be derived analytically from the probability function.
Information Self-Service with a Knowledge Base That Learns
Durbin, Stephen D., Warner, Doug, Richter, J. Neal, Gedeon, Zuzana
Delivering effective customer service over the internet requires attention to many aspects of knowledge management if it is to be both satisfying for customers and economical for the company or other organization. In RightNow ESERVICE CENTER, such management is built into the architecture and supported by automatically gathering metainformation about the documents held in the core knowledge base. A variety of AI techniques are used to facilitate the construction, maintenance, and navigation of the knowledge base. These techniques include collaborative filtering, swarm intelligence, fuzzy logic, natural language processing, text clustering, and classification rule learning. Customers using ESERVICE CENTER report dramatic decreases in support costs and increases in customer satisfaction because of the ease of use provided by the self-learning features of the knowledge base.
Data Clustering by Markovian Relaxation and the Information Bottleneck Method
We introduce a new, nonparametric and principled, distance based clustering method. This method combines a pairwise based approach with a vector-quantization method which provide a meaningful interpretation to the resulting clusters. The idea is based on turning the distance matrix into a Markov process and then examine the decay of mutual-information during the relaxation of this process. The clusters emerge as quasi-stable structures during this relaxation, and then are extracted using the information bottleneck method.
Data Clustering by Markovian Relaxation and the Information Bottleneck Method
We introduce a new, nonparametric and principled, distance based clustering method. This method combines a pairwise based approach with a vector-quantization method which provide a meaningful interpretation to the resulting clusters. The idea is based on turning the distance matrix into a Markov process and then examine the decay of mutual-information during the relaxation of this process. The clusters emerge as quasi-stable structures during this relaxation, and then are extracted using the information bottleneck method.