1,468 research outputs found
Legislative Evaluation of Social Welfare Programs: The Process and Consequences
Program review has increased substantially in recent years. There has been concern that the upsurge in policy evaluation would be detrimental to social welfare programs, where data is often unavailable, little agreement exists concerning specific goals and documenting success is often virtually impossible. In this analysis we compared the program evaluation of social welfare programs with non-social welfare programs. The review process differed substantially as did the recommendation made as a result of the review. Social welfare programs faced more criticisms than non-social welfare programs. However, the criticisms were less serious. Changes prior to the publication of the evaluation report were more common for social welfare programs. They were also considerably more likely to make significant administrative changes--action that helps then avoid legislative involvement. lon-social welfare programs were more than twice as likely to face changes mandated by the legislature. Those findings indicate that social welfare programs are not experiencing adverse consequences as a result of mandatory reviews
Evaluation of image features using a photorealistic virtual world
Image features are widely used in computer vision applications. They need to be robust to scene changes and image transformations. Designing and comparing feature descriptors requires the ability to evaluate their performance with respect to those transformations. We want to know how robust the descriptors are to changes in the lighting, scene, or viewing conditions. For this, we need ground truth data of different scenes viewed under different camera or lighting conditions in a controlled way. Such data is very difficult to gather in a real-world setting. We propose using a photorealistic virtual world to gain complete and repeatable control of the environment in order to evaluate image features. We calibrate our virtual world evaluations by comparing against feature rankings made from photographic data of the same subject matter (the Statue of Liberty). We find very similar feature rankings between the two datasets. We then use our virtual world to study the effects on descriptor performance of controlled changes in viewpoint and illumination. We also study the effect of augmenting the descriptors with depth information to improve performance.Quanta Computer (Firm)Shell ResearchUnited States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N00014-06-1-0734)United States. Office of Naval Research. Multidisciplinary University Research Initiative. CAREER (Award Number 0747120)United States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N000141010933)Microsoft CorporationAdobe SystemsGoogle (Firm
Matching and Predicting Street Level Images
The paradigm of matching images to a very large dataset
has been used for numerous vision tasks and is a powerful one. If the
image dataset is large enough, one can expect to nd good matches of
almost any image to the database, allowing label transfer [3, 15], and
image editing or enhancement [6, 11]. Users of this approach will want
to know how many images are required, and what features to use for
nding semantic relevant matches. Furthermore, for navigation tasks or
to exploit context, users will want to know the predictive quality of the
dataset: can we predict the image that would be seen under changes in
camera position?
We address these questions in detail for one category of images: street
level views. We have a dataset of images taken from an enumeration of
positions and viewpoints within Pittsburgh.We evaluate how well we can
match those images, using images from non-Pittsburgh cities, and how
well we can predict the images that would be seen under changes in cam-
era position. We compare performance for these tasks for eight di erent
feature sets, nding a feature set that outperforms the others (HOG).
A combination of all the features performs better in the prediction task
than any individual feature. We used Amazon Mechanical Turk workers
to rank the matches and predictions of di erent algorithm conditions by
comparing each one to the selection of a random image. This approach
can evaluate the e cacy of di erent feature sets and parameter settings
for the matching paradigm with other image categories.United States. Dept. of Defense (ARDA VACE)United States. National Geospatial-Intelligence Agency (NEGI-1582-04- 0004)United States. National Geospatial-Intelligence Agency (MURI Grant N00014-06-1-0734)France. Agence nationale de la recherche (project HFIBMR (ANR-07-BLAN- 0331-01))Institut national de recherche en informatique et en automatique (France)Xerox Fellowship Progra
Phase-based video motion processing
We introduce a technique to manipulate small movements in videos based on an analysis of motion in complex-valued image pyramids. Phase variations of the coefficients of a complex-valued steerable pyramid over time correspond to motion, and can be temporally processed and amplified to reveal imperceptible motions, or attenuated to remove distracting changes. This processing does not involve the computation of optical flow, and in comparison to the previous Eulerian Video Magnification method it supports larger amplification factors and is significantly less sensitive to noise. These improved capabilities broaden the set of applications for motion processing in videos. We demonstrate the advantages of this approach on synthetic and natural video sequences, and explore applications in scientific analysis, visualization and video enhancement.Shell ResearchUnited States. Defense Advanced Research Projects Agency. Soldier Centric Imaging via Computational CamerasNational Science Foundation (U.S.) (CGV-1111415)Cognex CorporationMicrosoft Research (PhD Fellowship)American Society for Engineering Education. National Defense Science and Engineering Graduate Fellowshi
CG2Real: Improving the Realism of Computer Generated Images using a Large Collection of Photographs
Computer Graphics (CG) has achieved a high level of realism, producing strikingly vivid images. This realism, however, comes at the cost of long and often expensive manual modeling, and most often humans can still distinguish between CG images and real images. We present a novel method to make CG images look more realistic that is simple and accessible to novice users. Our system uses a large collection of photographs gathered from online repositories. Given a CG image, we retrieve a small number of real images with similar global structure. We identify corresponding regions between the CG and real images using a novel mean-shift cosegmentation algorithm. The user can then automatically transfer color, tone, and texture from matching regions to the CG image. Our system only uses image processing operations and does not require a 3D model of the scene, making it fast and easy to integrate into digital content creation workflows. Results of a user study show that our improved CG images appear more realistic than the originals
Looking for imprints of the first stellar generations in metal-poor bulge field stars
© 2016 ESO. Context. Efforts to look for signatures of the first stars have concentrated on metal-poor halo objects. However, the low end of the bulge metallicity distribution has been shown to host some of the oldest objects in the Milky Way and hence this Galactic component potentially offers interesting targets to look at imprints of the first stellar generations. As a pilot project, we selected bulge field stars already identified in the ARGOS survey as having [Fe/H] 1 and oversolar [α/Fe] ratios, and we used FLAMES-UVES to obtain detailed abundances of key elements that are believed to reveal imprints of the first stellar generations. Aims. The main purpose of this study is to analyse selected ARGOS stars using new high-resolution (R ⌠45 000) and high-signal-tonoise (S=N > 100) spectra. We aim to derive their stellar parameters and elemental ratios, in particular the abundances of C, N, the α-elements O, Mg, Si, Ca, and Ti, the odd-Z elements Na and Al, the neutron-capture s-process dominated elements Y, Zr, La, and Ba, and the r-element Eu. Methods. High-resolution spectra of five field giant stars were obtained at the 8 m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. Spectroscopic parameters were derived based on the excitation and ionization equilibrium of Fe i and Fe ii. The abundance analysis was performed with a MARCS LTE spherical model atmosphere grid and the Turbospectrum spectrum synthesis code. Results.We confirm that the analysed stars are moderately metal-poor (-1:04â€[Fe/H]â€-0:43), non-carbon-enhanced (non-CEMP) with [C/Fe] â€+0:2, and α-enhanced.We find that our three most metal-poor stars are nitrogen enhanced. The α-enhancement suggests that these stars were formed from a gas enriched by core-collapse supernovae, and that the values are in agreement with results in the literature for bulge stars in the same metallicity range. No abundance anomalies (Na-O, Al-O, Al-Mg anti-correlations) were detected in our sample. The heavy elements Y, Zr, Ba, La, and Eu also exhibit oversolar abundances. Three out of the five stars analysed here show slightly enhanced [Y/Ba] ratios similar to those found in other metal-poor bulge globular clusters (NGC 6522 and M 62). Conclusions. This sample shows enhancement in the first-to-second peak abundance ratios of heavy elements, as well as dominantly s-process element excesses. This can be explained by different nucleosynthesis scenarios: (a) the main r-process plus extra mechanisms, such as the weak r-process; (b) mass transfer from asymptotic giant branch stars in binary systems; (c) an early generation of fast-rotating massive stars. Larger samples of moderately metal-poor bulge stars, with detailed chemical abundances, are needed to better constrain the source of dominantly s-process elements in the early Universe
Intraoperative evaluation of mitral valve regurgitation and repair by transesophageal echocardiography: Incidence and significance of systolic anterior motion
AbstractObjectives. This study was designed to delineate the utility and results of intraoperative transesophageal echocardiography in the evaluation of patients undergoing mural valve repair for mitral regurgitation.Background. Mitral valve reconstruction offers many advantages over prosthetic valve replacement. Intraoperative assessment of valve competence after repair is vital to the effectiveness of this procedure.Methods. Intraoperative transesophageal echocardiography was performed in 143 patients undergoing mitral valve repair over a period of 23 months, Before and after repair, the functional morphology of the mitral apparatus was defined by twodimensional echocardiography; Doppler color flow imaging was used to clarify the mechanism of mitral regurgitation and to semiquantitate its severity.Results. There was significant improvement in the mean mitral regurgitation grade by composite intraoperative transesophageal echocardiography after valve repair (3.6 ± 0.8 to 0.7 ± 0.7; p < 0.00001). Excellent results from initial repair with grade †1 residual mitral regurgitation were observed in 88.1% of patients. Significant residual mitral regurgitation (grade ℠3) was identified in 11 patients (7.7%); 5 underwent prosthetic valve replacement, 5 had revision of the initial repair and 1 patient had observation only. Of the 100 patients with a myxomatous mitral valve, the risk of grade ℠3 mitral regurgitation after initial repair was 1.7% in patients with isolated posterior leaflet disease compared with 22.5% in patients with anterior or bileaflet disease.Severe systolic anterior motion of the mitral apparatus causing grade 2 to 4 mitral regurgitation was present in 13 patients (9.1%) after cardiopulmonary bypass. In 8 patients (5.6%), systolic anterior motion resolved immediately with correction of hyperdynamic hemodynamic status, resulting in grade †1 residual mitral regurgitation without further operative intervention.Transthoracic echocardiography before hospital discharge demonstrated grade †1 residual mitral regurgitation in 86.4% of 132 patients studied. A significant discrepancy (> 1 grade) in residual mitral regurgitation by predischarge transthoracic versus intraoperative transesophageal echocardiography was noted in 17 patients (12.9%).Conclusions. Transesophageal echocardiography is a valuable adjunct in the intraoperative assessment of mitral valve repair
Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective
This essay is inspired by the ideas and research examined in the special section on âStakeholder Marketingâ of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing âprosocietyâ and âproenvironmentâ perspectivesâorientations that are also in keeping with the public policy focus of this journal. Under the âhard formâ of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society
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