655 research outputs found
Internal organizational communication during crisis situations: the effect of supportive messages on employee stress levels
This study investigates the effects of supportive messages from immediate supervisors or CEO\u27s on employees during crisis situations. Supportive messages are hypothesized to decrease the stress levels of employees. The extent to which supportive messages from managers or executives during crisis situations affect employee perceptions of support from their organization, their CEO, and their immediate supervisor is also explored. During the research process, 78 volunteer participants received one of three messages from a hypothetical organization following a hypothetical crisis situation. Spearman\u27s ranked correlations comparing reported support with reported stress levels indicate that, for the group studied, there is a negative correlation between perceived organizational support and employee stress levels
Non-Gaussian Discriminative Factor Models via the Max-Margin Rank-Likelihood
We consider the problem of discriminative factor analysis for data that are
in general non-Gaussian. A Bayesian model based on the ranks of the data is
proposed. We first introduce a new {\em max-margin} version of the
rank-likelihood. A discriminative factor model is then developed, integrating
the max-margin rank-likelihood and (linear) Bayesian support vector machines,
which are also built on the max-margin principle. The discriminative factor
model is further extended to the {\em nonlinear} case through mixtures of local
linear classifiers, via Dirichlet processes. Fully local conjugacy of the model
yields efficient inference with both Markov Chain Monte Carlo and variational
Bayes approaches. Extensive experiments on benchmark and real data demonstrate
superior performance of the proposed model and its potential for applications
in computational biology.Comment: 14 pages, 7 figures, ICML 201
Cross-Domain Multitask Learning with Latent Probit Models
Learning multiple tasks across heterogeneous domains is a challenging problem since the feature space may not be the same for different tasks. We assume the data in multiple tasks are generated from a latent common domain via sparse domain transforms and propose a latent probit model (LPM) to jointly learn the domain transforms, and the shared probit classifier in the common domain. To learn meaningful task relatedness and avoid over-fitting in classification, we introduce sparsity in the domain transforms matrices, as well as in the common classifier. We derive theoretical bounds for the estimation error of the classifier in terms of the sparsity of domain transforms. An expectation-maximization algorithm is derived for learning the LPM. The effectiveness of the approach is demonstrated on several real datasets
Variability in the Implementation of State-Wide Law across Urban Environments: A Case Study using Sex Offender Law as an Example
CPACS Urban Research Awards
Part of the mission of the College of Public Affairs and Community Service (CPACS) is to conduct research, especially as it relates to concerns of our local and statewide constituencies. CPACS has always had an urban mission, and one way that mission is served is to preform applied research relevant to urban society in general, and the Omaha metropolitan area and other Nebraska urban communities in particular. Beginning in 2014, the CPACS Dean provided funding for the projects with high relevance to current urban issues, with the potential to apply the findings to practice in Nebraska, Iowa, and beyond
Studies on supportive care in oral mucositis:Random or randomised?
During the last decades, measures on supportive care are considered standard in everyday oncology practice. Supportive care measures not only prevent or ameliorate complications of antitumour therapy and thereby increase the patients' quality of life, they also make anti-tumour therapy in sufficient doses possible. Due to large-scaled clinical trials, the treatment of chemotherapy- and radiotherapy-induced nausea and vomiting has become evidence-based in current practice. The development of guidelines on the use of haematopoetic growth factors in chemotherapy-induced leucopenia and anaemia was also based on clinical trials. For the prevention and treatment of oral mucositis, however, scarcely any evidence exists. [...
Information-Theoretic Compressive Measurement Design
An information-theoretic projection design framework is proposed, of interest for feature design and compressive measurements. Both Gaussian and Poisson measurement models are considered. The gradient of a proposed information-theoretic metric (ITM) is derived, and a gradient-descent algorithm is applied in design; connections are made to the information bottleneck. The fundamental solution structure of such design is revealed in the case of a Gaussian measurement model and arbitrary input statistics. This new theoretical result reveals how ITM parameter settings impact the number of needed projection measurements, with this verified experimentally. The ITM achieves promising results on real data, for both signal recovery and classification
Bayesian Gaussian Copula Factor Models for Mixed Data.
Gaussian factor models have proven widely useful for parsimoniously characterizing dependence in multivariate data. There is a rich literature on their extension to mixed categorical and continuous variables, using latent Gaussian variables or through generalized latent trait models acommodating measurements in the exponential family. However, when generalizing to non-Gaussian measured variables the latent variables typically influence both the dependence structure and the form of the marginal distributions, complicating interpretation and introducing artifacts. To address this problem we propose a novel class of Bayesian Gaussian copula factor models which decouple the latent factors from the marginal distributions. A semiparametric specification for the marginals based on the extended rank likelihood yields straightforward implementation and substantial computational gains. We provide new theoretical and empirical justifications for using this likelihood in Bayesian inference. We propose new default priors for the factor loadings and develop efficient parameter-expanded Gibbs sampling for posterior computation. The methods are evaluated through simulations and applied to a dataset in political science. The models in this paper are implemented in the R package bfa
Scalable Control Variates for Monte Carlo Methods via Stochastic Optimization
Control variates are a well-established tool to reduce the variance of Monte Carlo estimators. However, for large-scale problems including high-dimensional and large-sample settings, their advantages can be outweighed by a substantial computational cost. This paper considers control variates based on Stein operators, presenting a framework that encompasses and generalizes existing approaches that use polynomials, kernels and neural networks. A learning strategy based on minimising a variational objective through stochastic optimization is proposed, leading to scalable and effective control variates. Novel theoretical results are presented to provide insight into the variance reduction that can be achieved, and an empirical assessment, including applications to Bayesian inference, is provided in support
Communications inspired linear discriminant analysis
We study the problem of supervised linear dimensionality reduction, taking an information-theoretic viewpoint. The linear projection matrix is designed by maximizing the mutual information between the projected signal and the class label. By harnessing a recent theoretical result on the gradient of mutual information, the above optimization problem can be solved directly using gradient descent, without requiring simplification of the objective function. Theoretical analysis and empirical comparison are made between the proposed method and two closely related methods, and comparisons are also made with a method in which Rényi entropy is used to define the mutual information (in this case the gradient may be computed simply, under a special parameter setting). Relative to these alternative approaches, the proposed method achieves promising results on real datasets. Copyright 2012 by the author(s)/owner(s)
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