6,006 research outputs found
An Efficient Mode Decision Algorithm Based on Dynamic Grouping and Adaptive Adjustment for H.264/AVC
“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”The rate distortion optimization (RDO) enabled mode decision (MD) is one of the most important techniques introduced by H.264/AVC. By adopting the exhaustive calculation of rate distortion, the optimal MD enhances the video encoding quality. However, the computational complexity is significantly increased, which is a key challenge for real-time and low power consumption applications. This paper presents a new fast MD algorithm for highly efficient H.264/AVC encoder. The proposed algorithm employs a dynamic group of candidate inter/intra modes to reduce the computational cost. In order to minimize the performance loss incurred by improper mode selection for the previously encoded frames, an adaptive adjustment scheme based on the undulation of bitrate and PSNR is suggested. Experimental results show that the proposed algorithm reduces the encoding time by 35% on average, and the loss of PSNR is usually limited in 0.1 dB with less than 1% increase of bitrate
An efficient fast mode decision algorithm for H.264/AVC intra/inter predictions
H.264/AVC is the newest video coding standard, which outperforms the former standards in video coding efficiency in terms of improved video quality and decreased bitrate. Variable block size based mode decision (MD) with rate distortion optimization (RDO) is one of the most impressive new techniques employed in H.264/AVC. However, the improvement on performance is achieved at the expense of significantly increased computational complexity, which is a key challenge for real-time applications. An efficient fast mode decision algorithm is then proposed in this paper. By exploiting the correlation between macroblocks and the statistical characteristics of sub-macroblock in MD, the video encoding time can be reduced 52.19% on average. Furthermore, the motion speed based adjustment scheme was introduced to minimize the degradation of performanc
Probing Dark Energy with the Kunlun Dark Universe Survey Telescope
Dark energy is an important science driver of many upcoming large-scale
surveys. With small, stable seeing and low thermal infrared background, Dome A,
Antarctica, offers a unique opportunity for shedding light on fundamental
questions about the universe. We show that a deep, high-resolution imaging
survey of 10,000 square degrees in \emph{ugrizyJH} bands can provide
competitive constraints on dark energy equation of state parameters using type
Ia supernovae, baryon acoustic oscillations, and weak lensing techniques. Such
a survey may be partially achieved with a coordinated effort of the Kunlun Dark
Universe Survey Telescope (KDUST) in \emph{yJH} bands over 5000--10,000 deg
and the Large Synoptic Survey Telescope in \emph{ugrizy} bands over the same
area. Moreover, the joint survey can take advantage of the high-resolution
imaging at Dome A to further tighten the constraints on dark energy and to
measure dark matter properties with strong lensing as well as galaxy--galaxy
weak lensing.Comment: 9 pages, 6 figure
Tunable spin-selective loading of a silicon spin qubit
The remarkable properties of silicon have made it the central material for
the fabrication of current microelectronic devices. Silicon's fundamental
properties also make it an attractive option for the development of devices for
spintronics and quantum information processing. The ability to manipulate and
measure spins of single electrons is crucial for these applications. Here we
report the manipulation and measurement of a single spin in a quantum dot
fabricated in a silicon/silicon-germanium heterostructure. We demonstrate that
the rate of loading of electrons into the device can be tuned over an order of
magnitude using a gate voltage, that the spin state of the loaded electron
depends systematically on the loading voltage level, and that this tunability
arises because electron spins can be loaded through excited orbital states of
the quantum dot. The longitudinal spin relaxation time T1 is measured using
single-shot pulsed techniques and found to be ~3 seconds at a field of 1.85
Tesla. The demonstration of single spin measurement as well as a long spin
relaxation time and tunability of the loading are all favorable properties for
spintronics and quantum information processing applications.Comment: 4 pages, 3 figures, Supplemental Informatio
Single-shot measurement of triplet-singlet relaxation in a Si/SiGe double quantum dot
We investigate the lifetime of two-electron spin states in a few-electron
Si/SiGe double dot. At the transition between the (1,1) and (0,2) charge
occupations, Pauli spin blockade provides a readout mechanism for the spin
state. We use the statistics of repeated single-shot measurements to extract
the lifetimes of multiple states simultaneously. At zero magnetic field, we
find that all three triplet states have equal lifetimes, as expected, and this
time is ~10 ms. At non-zero field, the T0 lifetime is unchanged, whereas the T-
lifetime increases monotonically with field, reaching 3 seconds at 1 T.Comment: 4 pages, 3 figures, supplemental information. Typos fixed; updated to
submitted versio
Exploring Dark Energy with Next-Generation Photometric Redshift Surveys
The coming decade will be an exciting period for dark energy research, during which astronomers will address the question of what drives the accelerated cosmic expansion as first revealed by type Ia supernova (SN) distances, and confirmed by later observations. The mystery of dark energy poses a challenge of such magnitude that, as stated by the Dark Energy Task Force (DETF), nothing short of a revolution in our understanding of fundamental physics will be required to achieve a full understanding of the cosmic acceleration. The lack of multiple complementary precision observations is a major obstacle in developing lines of attack for dark energy theory. This lack is precisely what next-generation surveys will address via the powerful techniques of weak lensing (WL) and baryon acoustic oscillations (BAO) -- galaxy correlations more generally -- in addition to SNe, cluster counts, and other probes of geometry and growth of structure. Because of their unprecedented statistical power, these surveys demand an accurate understanding of the observables and tight control of systematics. This white paper highlights the opportunities, approaches, prospects, and challenges relevant to dark energy studies with wide-deep multiwavelength photometric redshift surveys. Quantitative predictions are presented for a 20000 sq. deg. ground-based 6-band (ugrizy) survey with 5-sigma depth of r~27.5, i.e., a Stage 4 survey as defined by the DETF
Cachexia and protein-energy wasting in children with chronic kidney disease
Children with chronic kidney disease (CKD) are at risk for “cachexia” or “protein-energy wasting” (PEW). These terms describe a pathophysiologic process resulting in the loss of muscle, with or without loss of fat, and involving maladaptive responses, including anorexia and elevated metabolic rate. PEW has been defined specifically in relation to CKD. We review the diagnostic criteria for cachexia and PEW in CKD and consider the limitations and applicability of these criteria to children with CKD. In addition, we present an overview of the manifestations and mechanisms of cachexia and PEW. A host of pathogenetic factors are considered, including systemic inflammation, endocrine perturbations, and abnormal neuropeptide signaling, as well as poor nutritional intake. Mortality risk, which is 100- to 200-fold higher in patients with end-stage renal disease than in the general population, is strongly correlated with the components of cachexia/PEW. Further research into the causes and consequences of wasting and growth retardation is needed in order to improve the survival and quality of life for children with CKD
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Aryl hydrocarbon receptor activation during in vitro and in vivo digestion of raw and cooked broccoli (brassica oleracea var. Italica)
Broccoli is rich in glucosinolates, which can be converted upon chewing and processing into Aryl hydrocarbon Receptor (AhR) ligands. Activation of AhR plays an important role in overall gut homeostasis but the role of broccoli processing on the generation of AhR ligands is still largely unknown. In this study, the effects of temperature, cooking method (steaming versus boiling), gastric pH and further digestion of broccoli on AhR activation were investigated in vitro and in ileostomy subjects. For the in vitro study, raw, steamed (t = 3 min and t = 6 min) and boiled (t = 3 min and t = 6 min) broccoli were digested in vitro with different gastric pH. In the in vivo ileostomy study, 8 subjects received a broccoli soup or a broccoli soup plus an exogenous myrosinase source. AhR activation was measured in both in vitro and in vivo samples by using HepG2-Lucia™ AhR reporter cells. Cooking broccoli reduced the AhR activation measured after gastric digestion in vitro, but no effect of gastric pH was found. Indole AhR ligands were not detected or detected at very low levels both after intestinal in vitro digestion and in the ileostomy patient samples, which resulted in no AhR activation. This suggests that the evaluation of the relevance of glucosinolates for AhR modulation in the gut cannot prescind from the way broccoli is processed, and that broccoli consumption does not necessarily produce substantial amounts of AhR ligands in the large intestine
Semiparametric regression methods for temporal processes subject to multiple sources of censoring
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155547/1/cjs11528.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155547/2/cjs11528_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155547/3/cjs11528-sup-0002-SuppInfo2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155547/4/cjs11528-sup-0001-SuppInfo1.pd
The free energy in the Derrida--Retaux recursive model
We are interested in a simple max-type recursive model studied by Derrida and
Retaux (2014) in the context of a physics problem, and find a wide range for
the exponent in the free energy in the nearly supercritical regime
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