We show that an algebraic 2-Calabi-Yau triangulated category over an algebraically closed field is a cluster category if it contains a cluster tilting subcategory whose quiver has no oriented cycles. We prove a similar characterization for higher cluster categories. As a first application, we show that the stable category of maximal Cohen-Macaulay modules over a certain isolated singularity of ...

The paper presents a clustering based approach for consumers’ classification in representative categories characterized by typical load profiles. For determination of the consumption categories, every customer must be characterized by the following primary information: daily (monthly) energy consumption, average load and peak load. The used database contains the daily load curves corresponding ...

A very natural approach to categorization is similaritybased clustering. We propose a visual representation which can be used with such a mechanism for the acquisition of spatial relation categories. We also show how supervision can be helpful in cases where basic similarity is low by proposing a learning mechanism which operates both in the presence and in the absence of words.

Since their inception, distributional models of semantics have been criticized as inadequate cognitive theories of human semantic learning and representation. A principal challenge is that the representations derived by distributional models are purely symbolic and are not grounded in perception and action; this challenge has led many to favor feature-based models of semantic representation. We...

We propose an unsupervised information extraction system, which exploits the structured information in the form of HTML tables to build meaningful sets of entities belonging to certain categories. Due to redundancy on the Web, we believe that entities belonging to important categories will frequently co-occur in table columns. We present a clustering algorithm to cluster such frequently occurri...

We classify mutual funds using cluster analysis and examine whether the categories created by clusters are the same as those assigned by the invest ment objectives Since mutual funds are usually classi ed based on their investment objectives clustering funds based on their nancial characteris tics rather than their investment objectives could explain why some mutual funds do not perform accordi...

In two experiments with categorized lists, we asked whether the testing effect in free recall is related to enhancements in organizational processing. During a first phase in Experiment 1, subjects studied one list over eight consecutive trials, they studied another list six times while taking two interspersed recall tests, and they learned a third list in four alternating study and test trials...