47 research outputs found
Visual Comfort Assessment for Stereoscopic Image Retargeting
In recent years, visual comfort assessment (VCA) for 3D/stereoscopic content
has aroused extensive attention. However, much less work has been done on the
perceptual evaluation of stereoscopic image retargeting. In this paper, we
first build a Stereoscopic Image Retargeting Database (SIRD), which contains
source images and retargeted images produced by four typical stereoscopic
retargeting methods. Then, the subjective experiment is conducted to assess
four aspects of visual distortion, i.e. visual comfort, image quality, depth
quality and the overall quality. Furthermore, we propose a Visual Comfort
Assessment metric for Stereoscopic Image Retargeting (VCA-SIR). Based on the
characteristics of stereoscopic retargeted images, the proposed model
introduces novel features like disparity range, boundary disparity as well as
disparity intensity distribution into the assessment model. Experimental
results demonstrate that VCA-SIR can achieve high consistency with subjective
perception
Empowering Collaborative Filtering with Principled Adversarial Contrastive Loss
Contrastive Learning (CL) has achieved impressive performance in
self-supervised learning tasks, showing superior generalization ability.
Inspired by the success, adopting CL into collaborative filtering (CF) is
prevailing in semi-supervised top-K recommendations. The basic idea is to
routinely conduct heuristic-based data augmentation and apply contrastive
losses (e.g., InfoNCE) on the augmented views. Yet, some CF-tailored challenges
make this adoption suboptimal, such as the issue of out-of-distribution, the
risk of false negatives, and the nature of top-K evaluation. They necessitate
the CL-based CF scheme to focus more on mining hard negatives and
distinguishing false negatives from the vast unlabeled user-item interactions,
for informative contrast signals. Worse still, there is limited understanding
of contrastive loss in CF methods, especially w.r.t. its generalization
ability. To bridge the gap, we delve into the reasons underpinning the success
of contrastive loss in CF, and propose a principled Adversarial InfoNCE loss
(AdvInfoNCE), which is a variant of InfoNCE, specially tailored for CF methods.
AdvInfoNCE adaptively explores and assigns hardness to each negative instance
in an adversarial fashion and further utilizes a fine-grained hardness-aware
ranking criterion to empower the recommender's generalization ability. Training
CF models with AdvInfoNCE, we validate the effectiveness of AdvInfoNCE on both
synthetic and real-world benchmark datasets, thus showing its generalization
ability to mitigate out-of-distribution problems. Given the theoretical
guarantees and empirical superiority of AdvInfoNCE over most contrastive loss
functions, we advocate its adoption as a standard loss in recommender systems,
particularly for the out-of-distribution tasks. Codes are available at
https://github.com/LehengTHU/AdvInfoNCE.Comment: Accepted to NeurIPS 202
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with
new instrumentation and new surveys focused on Galactic structure and chemical
evolution, measurements of the baryon oscillation feature in the clustering of
galaxies and the quasar Ly alpha forest, and a radial velocity search for
planets around ~8000 stars. This paper describes the first data release of
SDSS-III (and the eighth counting from the beginning of the SDSS). The release
includes five-band imaging of roughly 5200 deg^2 in the Southern Galactic Cap,
bringing the total footprint of the SDSS imaging to 14,555 deg^2, or over a
third of the Celestial Sphere. All the imaging data have been reprocessed with
an improved sky-subtraction algorithm and a final, self-consistent photometric
recalibration and flat-field determination. This release also includes all data
from the second phase of the Sloan Extension for Galactic Understanding and
Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars
at both high and low Galactic latitudes. All the more than half a million
stellar spectra obtained with the SDSS spectrograph have been reprocessed
through an improved stellar parameters pipeline, which has better determination
of metallicity for high metallicity stars.Comment: Astrophysical Journal Supplements, in press (minor updates from
submitted version
Sciences for The 2.5-meter Wide Field Survey Telescope (WFST)
The Wide Field Survey Telescope (WFST) is a dedicated photometric survey
facility under construction jointly by the University of Science and Technology
of China and Purple Mountain Observatory. It is equipped with a primary mirror
of 2.5m in diameter, an active optical system, and a mosaic CCD camera of 0.73
Gpix on the main focus plane to achieve high-quality imaging over a field of
view of 6.5 square degrees. The installation of WFST in the Lenghu observing
site is planned to happen in the summer of 2023, and the operation is scheduled
to commence within three months afterward. WFST will scan the northern sky in
four optical bands (u, g, r, and i) at cadences from hourly/daily to
semi-weekly in the deep high-cadence survey (DHS) and the wide field survey
(WFS) programs, respectively. WFS reaches a depth of 22.27, 23.32, 22.84, and
22.31 in AB magnitudes in a nominal 30-second exposure in the four bands during
a photometric night, respectively, enabling us to search tremendous amount of
transients in the low-z universe and systematically investigate the variability
of Galactic and extragalactic objects. Intranight 90s exposures as deep as 23
and 24 mag in u and g bands via DHS provide a unique opportunity to facilitate
explorations of energetic transients in demand for high sensitivity, including
the electromagnetic counterparts of gravitational-wave events detected by the
second/third-generation GW detectors, supernovae within a few hours of their
explosions, tidal disruption events and luminous fast optical transients even
beyond a redshift of 1. Meanwhile, the final 6-year co-added images,
anticipated to reach g about 25.5 mag in WFS or even deeper by 1.5 mag in DHS,
will be of significant value to general Galactic and extragalactic sciences.
The highly uniform legacy surveys of WFST will also serve as an indispensable
complement to those of LSST which monitors the southern sky.Comment: 46 pages, submitted to SCMP
Erratum: “The eighth data release of the Sloan Digital Sky Survey: first data from SDSS-III” (2011, ApJS, 193, 29)
Section 3.5 of Aihara et al. (2011) described various sources of systematic error in the astrometry of the imaging data of the Sloan Digital Sky Survey (SDSS). In addition to these sources of error, there is an additional and more serious error, which introduces a large systematic shift in the astrometry over a large area around the north celestial pole. The region has irregular boundaries but in places extends as far south as declination δ ≈ 41◦. The sense of the shift is that the positions of all sources in the affected area are offset by roughly 250 mas in a northwest direction. We have updated the SDSS online documentation to reflect these errors, and to provide detailed quality information for each SDSS field
Comparison of Electronic Taxpayer Services in OECD Countries and Recommendations for China Comparison of Electronic Taxpayer Services in OECD Countries and Recommendations for China
Through comparing development trend electronic taxpayer services in OECD countries and analyzing its drawbacks, it gained beneficial experience of electronic taxpayer services. Then, it came up with policy recommendations for China. It is recommended that China should raise the electronic taxpayer services to national strategy level, improve the efficiency of electronic taxpayer services in line with the taxpayer-centered principle, develop ways of electronic taxpayer services with Chinese characteristics, increase convenience for taxpayers on the precondition of guaranteeing information security, make effort to reduce compliance costs of taxpayers, and promote popularization of electronic taxpayer services with the framework of laws
International Comparison, Regional Characteristics and Regulatory Management of Structural Rise in the Prices of Chinese Industrial and Agricultural Products
China's price fluctuations increasingly exhibit significant structural characteristics, and since 2003, there have been several rounds of significant structural price rise. The degree of structural rise in the prices of industrial and agricultural products in China is not only higher than in the general developed countries and developing countries, but also more prominent than in other transition economies. And the structural rise in the prices of Chinese industrial and agricultural products exhibits significant economic zone differences: the structural fluctuations are the greatest in the central and western regions, significantly higher than in the eastern regions as well as the national average. From the perspective of causes of structural rise in the prices of Chinese industrial and agricultural products, the government must aim to coordinate the industrial and agricultural investments and bridge the gap in the industrial and agricultural technologies and supply capacity