Log-Sobolev inequalities: Different roles of Ric and Hess

Let $P_t$ be the diffusion semigroup generated by $L:=\Delta +\nabla V$ on a complete connected Riemannian manifold with $\operatorname {Ric}\ge-(\sigma ^2\rho_o^2+c)$ for some constants $\sigma, c>0$ and $\rho_o$ the Riemannian distance to a fixed point. It is shown that $P_t$ is hypercontractive, or the log-Sobolev inequality holds for the associated Dirichlet form, provided $-\operatorname {Hess}_V\ge\delta$ holds outside of a compact set for some constant $\delta >(1+\sqrt{2})\sigma \sqrt{d-1}.$ This indicates, at least in finite dimensions, that $\operatorname {Ric}$ and $-\operatorname {Hess}_V$ play quite different roles for the log-Sobolev inequality to hold. The supercontractivity and the ultracontractivity are also studied.Comment: Published in at http://dx.doi.org/10.1214/08-AOP444 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Different roles of similarity and predictability in auditory stream segregation

Sound sources often emit trains of discrete sounds, such as a series of footsteps. Previously, two dif¬ferent principles have been suggested for how the human auditory system binds discrete sounds to¬gether into perceptual units. The feature similarity principle is based on linking sounds with similar characteristics over time. The predictability principle is based on linking sounds that follow each other in a predictable manner. The present study compared the effects of these two principles. Participants were presented with tone sequences and instructed to continuously indicate whether they perceived a single coherent sequence or two concurrent streams of sound. We investigated the influence of separate manipulations of similarity and predictability on these perceptual reports. Both grouping principles affected perception of the tone sequences, albeit with different characteristics. In particular, results suggest that whereas predictability is only analyzed for the currently perceived sound organization, feature similarity is also analyzed for alternative groupings of sound. Moreover, changing similarity or predictability within an ongoing sound sequence led to markedly different dynamic effects. Taken together, these results provide evidence for different roles of similarity and predictability in auditory scene analysis, suggesting that forming auditory stream representations and competition between alter¬natives rely on partly different processes

Offenders' Crime Narratives across Different Types of Crimes

The current study explores the roles offenders see themselves playing during an offence and their relationship to different crime types. One hundred and twenty incarcerated offenders indicated the narrative roles they acted out whilst committing a specific crime they remembered well. The data were subjected to Smallest Space Analysis (SSA) and four themes were identified: Hero, Professional, Revenger and Victim in line with the recent theoretical framework posited for Narrative Offence Roles (Youngs & Canter, 2012). Further analysis showed that different subsets of crimes were more like to be associated with different narrative offence roles. Hero and Professional were found to be associated with property offences (theft, burglary and shoplifting), drug offences and robbery and Revenger and Victim were found to be associated with violence, sexual offences and murder. The theoretical implications for understanding crime on the basis of offenders' narrative roles as well as practical implications are discussed

Situation Recognition with Graph Neural Networks

We address the problem of recognizing situations in images. Given an image, the task is to predict the most salient verb (action), and fill its semantic roles such as who is performing the action, what is the source and target of the action, etc. Different verbs have different roles (e.g. attacking has weapon), and each role can take on many possible values (nouns). We propose a model based on Graph Neural Networks that allows us to efficiently capture joint dependencies between roles using neural networks defined on a graph. Experiments with different graph connectivities show that our approach that propagates information between roles significantly outperforms existing work, as well as multiple baselines. We obtain roughly 3-5% improvement over previous work in predicting the full situation. We also provide a thorough qualitative analysis of our model and influence of different roles in the verbs.Comment: ICCV201

Roles as a structuring tool in online discussion groups: the differential impact of different roles on social knowledge construction

A

Competition and Performance: The Different Roles of Capital and Labor

Neoclassical economists argue that competition promotes efficiency. They consider technology as given though. In the long run technological progress is an important determinant of the level of welfare and Schumpeter argued that monopoly rents help entrepreneurs to capture the gains of R&D and hence to invest in it. We investigate the overall effect of competition on performance. Performance is measured by TFP-growth. As a negative measure of competition we use rent. Rent is defined as the excess factor rewards over and above their perfectly competitive values (marginal productivities). Input-output analysis enables us to calculate rent for the Canadian sectors over a thirty-year period and to decompose it in its capital and labor components. In line with the literature we find that rent has no significant influence on productivity. We find an interesting result however: the components influence performance in opposite directions. Capital rent has a positive role and labor rent a negative one. The neoclassical economists and Schumpeter seem both right, but the mechanisms differ. The use of rent as a source of funding for R&D applies to capital and the argument that rent yields slack pertains to labor.mathematical economics and econometrics ;

Negotiation Games: Acquiring Skills by Playing

This paper shows the research done at the School of Industrial Engineers (ETSII) of the Technical University of Madrid (UPM), in two consecutive academic courses. In this negotiation game each team is formed by three students playing different roles, with a different degree of complexity. The game is played three different times changing the conditions and doing the Zones of Possible Agreement (ZOPA) smaller so the negotiation is going “harder” and it was more difficult for the team to achieve an agreement. Roles were distributed according to the student’s experience, since it was understood that difficulty of the roles was different, especially when there was set a time limit for negotiation. The combination of playing and training has shown that students without particularly good negotiating skills at the beginning of the experiment attained better final results than those who have natural negotiating skills, but no benefit of training

Interpreters and cultural mediators – different but complementary roles

This article considers the roles of medical interpreters and cultural mediators and proposes that the two should be seen as separate. In the last six years cultural mediators have been trained in Ireland not to be interpreters but to help immigrants from other countries to access and use healthcare services as well as mediating in situations of conflict between health service providers and patients. Meanwhile, interpreters have been hired to bridge the language gap. Codes of ethics for medical interpreters and competencies of cultural mediators are considered in order to clarify role boundaries and to explore similarities and differences between the two roles