Spatio-temporal data is intrinsically high dimensional, so unsupervised modeling is only feasible if we can exploit structure in the process. When the dynamics are local in both space and time, this structure can be exploited by splitting the global field into many lower-dimensional "light cones". We review light cone decompositions for predictive state reconstruction, introducing three simple light cone algorithms. These methods allow for tractable inference of spatio-temporal data, such as full-frame video. The algorithms make few assumptions on the underlying process yet have good predictive performance and can provide distributions over spatio-temporal data, enabling sophisticated probabilistic inference.

I don't think K-means clustering in R has any special meaning, whatever package you use the basic K-means algorithm remains the same.

Process mining is a research field focused on the analysis of event data with the aim of extracting insights in processes. Applying process mining techniques on data from smart home environments has the potential to provide valuable insights in (un)healthy habits and to contribute to ambient assisted living solutions. Finding the right event labels to enable application of process mining techniques is however far from trivial, as simply using the triggering sensor as the label for sensor events results in uninformative models that allow for too much behavior (overgeneralizing). Refinements of sensor level event labels suggested by domain experts have shown to enable discovery of more precise and insightful process models. However, there exist no automated approach to generate refinements of event labels in the context of process mining. In this paper we propose a framework for automated generation of label refinements based on the time attribute of events. We show on a case study with real life smart home event data that behaviorally more specific, and therefore more insightful, process models can be found by using automatically generated refined labels in process discovery.

Several recent deep neural networks experiments leverage the generalist-specialist paradigm for classification. However, no formal study compared the performance of different clustering algorithms for class assignment. In this paper we perform such a study, suggest slight modifications to the clustering procedures, and propose a novel algorithm designed to optimize the performance of of the specialist-generalist classification system. Our experiments on the CIFAR-10 and CIFAR-100 datasets allow us to investigate situations for varying number of classes on similar data. We find that our \emph{greedy pairs} clustering algorithm consistently outperforms other alternatives, while the choice of the confusion matrix has little impact on the final performance.

Consider the problem of sparse clustering, where it is assumed that only a subset of the features are useful for clustering purposes. In the framework of the COSA method of Friedman and Meulman, subsequently improved in the form of the Sparse K-means method of Witten and Tibshirani, a natural and simpler hill-climbing approach is introduced. The new method is shown to be competitive with these two methods and others. Keywords: Sparse Clustering, Hill-climbing, High-dimensional, Feature Selection 1. Introduction Consider a typical setting for clusteringn items based on pairwise dissimilarities, withδ(i,j) denoting the dissimilarity between itemsi,j [n ] {1,...,n } . For concreteness, we assume thatδ(i,j) 0 and δ(i,i) 0 for all i,j [n ] . In principle, if we want to delineateκ clusters, the goal is (for example) to minimize the average within-cluster dissimilarity. Let C n κ denote the class of clusterings ofn items intoκ groups. For C C n κ, its average within-cluster dissimilarity is defined as [C ] k [κ ] 1 C 1 (k) i,j C 1 (k)δ(i,j). If under the Euclidean setting, we further define cluster centers µ k 1 n i C 1 (k)x i with k [κ ], (2) then the within-cluster dissimilarity can be rewritten as follows, [C ] k [κ ] 1 C 1 (k) i,j C 1 (k) x i x j 2 k [κ ] i C 1 (k) x i µ k 2 . The resulting optimization problem is the following: Given (δ(i,j) i,j [n ]), minimize [C ] over C C n κ .

In my last post, I showed how to find similar Game of Thrones episodes based on the characters that appear in different episodes. This allowed us to find similar episodes on an episode by episode basis, but I was curious whether there were groups of similar episodes that we could identify. A clustering algorithm groups similar documents together, where similarity is based on calculating a'distance' between documents. Documents separated by a small distance would be in the same cluster, whereas if there's a large distance between episodes then they'd probably be in different clusters. The KMeans algorithm clusters data by trying to separate samples in n groups of equal variance, minimizing a criterion known as the inertia or within-cluster sum-of-squares.

This paper investigates the use of distributed processing on the problem of emotion recognition from physiological sensors using a popular machine learning library on distributed mode. Specifically, we run a random forests classifier on the biosignal-data, which have been pre-processed to form exclusive groups in an unsupervised fashion, on a Cloudera cluster using Mahout. The use of distributed processing significantly reduces the time required for the offline training of the classifier, enabling processing of large physiological datasets through many iterations.

This work draws its inspiration from three important sources of research on dissimilarity-based clustering and intertwines those three threads into a consistent principled functorial theory of clustering. Those three are the overlapping clustering of Jardine and Sibson, the functorial approach of Carlsson and Memoli to partition-based clustering, and the Isbell/Dress school's study of injective envelopes. Carlsson and Memoli introduce the idea of viewing clustering methods as functors from a category of metric spaces to a category of clusters, with functoriality subsuming many desirable properties. Our first series of results extends their theory of functorial clustering schemes to methods that allow overlapping clusters in the spirit of Jardine and Sibson. This obviates some of the unpleasant effects of chaining that occur, for example with single-linkage clustering. We prove an equivalence between these general overlapping clustering functors and projections of weight spaces to what we term clustering domains, by focusing on the order structure determined by the morphisms. As a specific application of this machinery, we are able to prove that there are no functorial projections to cut metrics, or even to tree metrics. Finally, although we focus less on the construction of clustering methods (clustering domains) derived from injective envelopes, we lay out some preliminary results, that hopefully will give a feel for how the third leg of the stool comes into play.

Take a satellite image, and extract the pixels into a uniform 3-D color space. Then run a clustering algorithm on those pixels, to extract a number of clusters. The centroids of those clusters them make a representative palette of the image. The R package earthtones by Will Cornwell, Mitch Lyons, and Nick Murray -- now available on CRAN -- does all this for you. Pass the get_earthtones function a latitude and longitude, and it will grab the Google Earth tile at the requested zoom level (8 works well for cities) and generate a palette with the desired number of colors.

Data clustering is the process of grouping items together based on similarities between the items of a group. Clustering can be used for data compression, data mining, pattern recognition, and machine learning. Examples of applications include clustering consumers into market segments, classifying manufactured units by their failure signatures, identifying crime hot spots, and identifying regions with similar geographical characteristics. Once clusters are defined, the next step may be to build a predictive model. TIBCO Spotfire makes it easy to perform clustering with these two popular out of box user-friendly solutions: 1. K-means Clustering 2. Hierarchical Clustering The k-means method is a popular and simple approach to perform clustering and Spotfire line charts help visualize data before performing calculations.