4,347 research outputs found

    Regularized Ordinal Regression and the ordinalNet R Package

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    Regularization techniques such as the lasso (Tibshirani 1996) and elastic net (Zou and Hastie 2005) can be used to improve regression model coefficient estimation and prediction accuracy, as well as to perform variable selection. Ordinal regression models are widely used in applications where the use of regularization could be beneficial; however, these models are not included in many popular software packages for regularized regression. We propose a coordinate descent algorithm to fit a broad class of ordinal regression models with an elastic net penalty. Furthermore, we demonstrate that each model in this class generalizes to a more flexible form, for instance to accommodate unordered categorical data. We introduce an elastic net penalty class that applies to both model forms. Additionally, this penalty can be used to shrink a non-ordinal model toward its ordinal counterpart. Finally, we introduce the R package ordinalNet, which implements the algorithm for this model class

    Impartial avoidance games for generating finite groups

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    We study an impartial avoidance game introduced by Anderson and Harary. The game is played by two players who alternately select previously unselected elements of a finite group. The first player who cannot select an element without making the set of jointly-selected elements into a generating set for the group loses the game. We develop criteria on the maximal subgroups that determine the nim-numbers of these games and use our criteria to study our game for several families of groups, including nilpotent, sporadic, and symmetric groups.Comment: 14 pages, 4 figures. Revised in response to comments from refere

    Impartial avoidance and achievement games for generating symmetric and alternating groups

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    We study two impartial games introduced by Anderson and Harary. Both games are played by two players who alternately select previously-unselected elements of a finite group. The first player who builds a generating set from the jointly-selected elements wins the first game. The first player who cannot select an element without building a generating set loses the second game. We determine the nim-numbers, and therefore the outcomes, of these games for symmetric and alternating groups.Comment: 12 pages. 2 tables/figures. This work was conducted during the third author's visit to DIMACS partially enabled through support from the National Science Foundation under grant number #CCF-1445755. Revised in response to comments from refere

    An Explanation of the Supervisory Model used by Elementary Principal Supervisors in the State of Missouri

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    The goal for this paper was to discuss the efforts a school district has taken to utilize elementary principal supervisors to build and develop principals’ leadership capacities. The question considered was: (1) How are principals supervised and evaluated in one district? Attempting to answer this question is an important step in operationalizing guiding principles that can be shared with principal supervisors. The discussion included the importance of standards, the modeling of instructional supervision by principal supervisors, the reliance of guiding questions and potential data sources. Additional critical factors included coaching with two-way communication based on a trusting, reflective relationship. As the role of principals’ leadership is elevated to increase the performance of teachers and thus the academic performance of students, principal supervisors should be able to provide principals ownership in their supervision and evaluation, evaluate performance based on standards and indicators, deliver feedback, develop trusting relationships, all by making frequent visits to principals’ schools to further the application of principals’ instructional leadership

    Vol. 1 Ch. 0 Preface

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    https://ideaexchange.uakron.edu/encountering_hopewell/1025/thumbnail.jp

    Appealability of District Court Orders Granting or Denying Stays of Arbitration under 28 U.S.C. Section 1292(a)(1)

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    Vol. 1 Ch. 4 Revealing Ritual Landscapes at the Hopewell Mound Group

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    https://ideaexchange.uakron.edu/encountering_hopewell/1003/thumbnail.jp
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