Disentangling Factors of Variation with Cycle-Consistent Variational Auto-Encoders

Generative models that learn disentangled representations for different factors of variation in an image can be very useful for targeted data augmentation. By sampling from the disentangled latent subspace of interest, we can efficiently generate new data necessary for a particular task. Learning disentangled representations is a challenging problem, especially when certain factors of variation are difficult to label. In this paper, we introduce a novel architecture that disentangles the latent space into two complementary subspaces by using only weak supervision in form of pairwise similarity labels. Inspired by the recent success of cycle-consistent adversarial architectures, we use cycle-consistency in a variational auto-encoder framework. Our non-adversarial approach is in contrast with the recent works that combine adversarial training with auto-encoders to disentangle representations. We show compelling results of disentangled latent subspaces on three datasets and compare with recent works that leverage adversarial training

The Effects of Human Resource Management Decisions on Shareholder Value

We examine the effects of selected human resource management decisions on the abnormal change in total shareholder return. Announcements of human resource decisions are classified into five types--general HR system announcements, compensation and benefits, staffing, shutdowns and relocations, and miscellaneous. Using an event study methodology we investigate whether any of these HR decisions had a discernible effect on either the level or variation of abnormal total shareholder return. We find no consistent pattern of increased or decreased valuation in response to the different types of HR announcements, even after controlling for the likely effect of such announcements on total compensation costs. We do find substantially increased variation in abnormal total shareholder return around the announcement date, which indicates that HR decisions do provide information to the stock market. The events associated with increased variation in total shareholder value are permanent staff reductions and shutdown/relocations. The absence of consistent valuation effects combined with the evidence of increased variation in shareholder value may be attributed to uncontrolled firm-specific factors, the categorization of the HR events or, simply, to the unique interpretations the market placed upon these events

Thermal conductivity of semiconductor superlattices: Experimental study of interface scattering

We present thermal conductivity measurements performed in three short-period (GaAs)_9(AlAs)_5 superlattices. The samples were grown at different temperatures, leading to different small scale roughness and broadening of the interfaces. The cross-plane conductivity is measured with a differential 3w method, at room temperature. The order of magnitude of the overall thermal conductivity variation is consistent with existing theoretical models, although the actual variation is smaller than expected

Fluctuations of the Lyapunov exponent in 2D disordered systems

We report a numerical investigation of the fluctuations of the Lyapunov exponent of a two dimensional non-interacting disordered system. While the ratio of the mean to the variance of the Lyapunov exponent is not constant, as it is in one dimension, its variation is consistent with the single parameter scaling hypothesis

Sigma, Kappa and fo(980) in E791 and BES II data

Both sigma and kappa are well established from E791 data on D->3pi and D->K-pi-pi$ and BES II data on J/Psi->omega-pi-pi and KKpipi. Fits to these data are accurately consistent with pi-pi and Kpi elastic scattering when one allows for the Adler zero which arises from Chiral Symmetry Breaking. The phase variation with mass is also consistent between elastic scattering and production data.Comment: 15 pages, 8 figures. A shortened version of hep-ex.0510014, conforming to page restrictions for Hadron05 Proceeding

Drivers of intrapopulation variation in resource use in a generalist predator, the macaroni penguin

Intrapopulation variation in resource use occurs in many populations of generalist predators with important community and evolutionary implications. One of the hypothesised mechanisms for such widespread variation is ecological opportunity, i.e. resource availability determined by intrinsic constraints and extrinsic conditions. We combined tracking data and stable isotope analysis to examine how breeding constraints and prey conditions influenced intrapopulation variation in resource use among macaroni penguins Eudyptes chrysolophus. Isotopic variation was also examined as a function of breeding success, individual traits and individual specialisation. Variation in isotope ratios was greatest across multiple tissue types when birds were able to undertake mid-range foraging trips (i.e. during incubation and pre-moult). This variation was highly consistent between years that spanned a 3-fold difference in local krill Euphausia superba density and was also highly consistent at the individual level between 2 years that had similar krill densities. However, by comparing our results with previous work on the same population, it appeared that a decrease in local prey availability can increase intrapopulation variation in resource use during periods with more restricted foraging ranges (i.e. during brood-guard and crèche). This study highlights the importance of considering ecological interactions that operate on multiple spatio-temporal scales when examining the drivers of resource use in populations of generalist predators