Direct QR factorizations for tall-and-skinny matrices in MapReduce architectures

The QR factorization and the SVD are two fundamental matrix decompositions with applications throughout scientific computing and data analysis. For matrices with many more rows than columns, so-called "tall-and-skinny matrices," there is a numerically stable, efficient, communication-avoiding algorithm for computing the QR factorization. It has been used in traditional high performance computing and grid computing environments. For MapReduce environments, existing methods to compute the QR decomposition use a numerically unstable approach that relies on indirectly computing the Q factor. In the best case, these methods require only two passes over the data. In this paper, we describe how to compute a stable tall-and-skinny QR factorization on a MapReduce architecture in only slightly more than 2 passes over the data. We can compute the SVD with only a small change and no difference in performance. We present a performance comparison between our new direct TSQR method, a standard unstable implementation for MapReduce (Cholesky QR), and the classic stable algorithm implemented for MapReduce (Householder QR). We find that our new stable method has a large performance advantage over the Householder QR method. This holds both in a theoretical performance model as well as in an actual implementation

Tensor Spectral Clustering for Partitioning Higher-order Network Structures

Spectral graph theory-based methods represent an important class of tools for studying the structure of networks. Spectral methods are based on a first-order Markov chain derived from a random walk on the graph and thus they cannot take advantage of important higher-order network substructures such as triangles, cycles, and feed-forward loops. Here we propose a Tensor Spectral Clustering (TSC) algorithm that allows for modeling higher-order network structures in a graph partitioning framework. Our TSC algorithm allows the user to specify which higher-order network structures (cycles, feed-forward loops, etc.) should be preserved by the network clustering. Higher-order network structures of interest are represented using a tensor, which we then partition by developing a multilinear spectral method. Our framework can be applied to discovering layered flows in networks as well as graph anomaly detection, which we illustrate on synthetic networks. In directed networks, a higher-order structure of particular interest is the directed 3-cycle, which captures feedback loops in networks. We demonstrate that our TSC algorithm produces large partitions that cut fewer directed 3-cycles than standard spectral clustering algorithms.Comment: SDM 201

\u3cem\u3eUnited States v. Dusenbery\u3c/em\u3e: Supreme Court Silence and the Lingering Echo of Due Process Violations in Civil Forfeiture Actions

Civil forfeiture, the process whereby all property substantially connected to illegal activity is forfeited to the United States government, plays an integral role in the United States criminal justice system, as it ensures that individuals do not profit from crime, and the proceeds from such actions help to finance the war on drugs and build new prisons. Because civil forfeiture encroaches upon an individual\u27s use and possession of property, Congress has established detailed procedures, including a notice requirement and the right to judicially contest the civil forfeiture action, that must be strictly followed before the Government is entitled to claim the property in question. Against this background, this Comment evaluates the current split amongst the United States Courts of Appeals regarding the issue of how to resolve civil forfeiture actions in which due process has been violated because the defendant did not receive proper notice of an administrative forfeiture proceeding, and the statute of limitations for filing a judicial forfeiture action has expired when the government becomes aware of this fact. Specifically, this Comment criticizes the Sixth Circuit\u27s recent decision, United States v. Dusenbery, in which the court concluded that the proper remedy is to restore the claimant\u27s right to judicially contest the forfeiture action and to put the government to its proofs under a probable cause standard, and argues that the Supreme Court of the United States should have granted Dusenbery\u27s petition for writ of certiorari and reversed the Sixth Circuit\u27s decision in Dusenbery because the reasons the majority cites to buttress its holding have no foundation in the law

\u3cem\u3eUnited States v. Dusenbery\u3c/em\u3e: Supreme Court Silence and the Lingering Echo of Due Process Violations in Civil Forfeiture Actions

Civil forfeiture, the process whereby all property substantially connected to illegal activity is forfeited to the United States government, plays an integral role in the United States criminal justice system, as it ensures that individuals do not profit from crime, and the proceeds from such actions help to finance the war on drugs and build new prisons. Because civil forfeiture encroaches upon an individual\u27s use and possession of property, Congress has established detailed procedures, including a notice requirement and the right to judicially contest the civil forfeiture action, that must be strictly followed before the Government is entitled to claim the property in question. Against this background, this Comment evaluates the current split amongst the United States Courts of Appeals regarding the issue of how to resolve civil forfeiture actions in which due process has been violated because the defendant did not receive proper notice of an administrative forfeiture proceeding, and the statute of limitations for filing a judicial forfeiture action has expired when the government becomes aware of this fact. Specifically, this Comment criticizes the Sixth Circuit\u27s recent decision, United States v. Dusenbery, in which the court concluded that the proper remedy is to restore the claimant\u27s right to judicially contest the forfeiture action and to put the government to its proofs under a probable cause standard, and argues that the Supreme Court of the United States should have granted Dusenbery\u27s petition for writ of certiorari and reversed the Sixth Circuit\u27s decision in Dusenbery because the reasons the majority cites to buttress its holding have no foundation in the law

Construing and body dissatisfaction in chronic depression: a study of body psychotherapy.

© 2018 Elsevier B.V. All rights reserved.The frequent association of depression with somatic symptoms suggests that body psychotherapy may be an appropriate therapeutic intervention for people with chronic depression. Using a subset of twenty-three participants from a randomized controlled trial that had demonstrated the effectiveness of such an intervention in reducing depressive symptoms, the present study investigated whether it may also impact aspects of construing which have been associated with depression. Patients presenting with chronic depression were randomly allocated to a treatment group or a waiting list group, which received body psychotherapy after a period on a waiting list. Correlations between repertory grid, questionnaire, and visual analogue measures indicated that depression and bodily dissatisfaction were associated with features of the content and structure of construing. There were no significant changes while patients were on the waiting list, but during treatment reduction in depression and bodily dissatisfaction, together with increase in self-esteem and quality of life, were accompanied by an increase in the salience of construing of the bodily self.Peer reviewe

A Process for Producing Ice Coverage Marine Information Objects (MIOs) in IHO S-57 Format

While global warming may be opening up more Arctic waters in the summer, ice still infests key shipping lanes in the northern hemisphere during the winter months. To safely navigate these areas, mariners rely on daily ice coverage charts produced by national governmental agencies. Ice charts are primarily issued in paper format or as a fax. However, there is increased interest to ice coverage information on vessel navigation systems such as an Electronic Chart and Display Information Systems (ECDIS). However, to do so, the ice information must be provided as a separate layer of information to the Electronic Navigational Chart (ENC)