185 research outputs found
A review of parallel computing for large-scale remote sensing image mosaicking
Interest in image mosaicking has been spurred by a wide variety of research and management needs. However, for large-scale applications, remote sensing image mosaicking usually requires significant computational capabilities. Several studies have attempted to apply parallel computing to improve image mosaicking algorithms and to speed up calculation process. The state of the art of this field has not yet been summarized, which is, however, essential for a better understanding and for further research of image mosaicking parallelism on a large scale. This paper provides a perspective on the current state of image mosaicking parallelization for large scale applications. We firstly introduce the motivation of image mosaicking parallel for large scale application, and analyze the difficulty and problem of parallel image mosaicking at large scale such as scheduling with huge number of dependent tasks, programming with multiple-step procedure, dealing with frequent I/O operation. Then we summarize the existing studies of parallel computing in image mosaicking for large scale applications with respect to problem decomposition and parallel strategy, parallel architecture, task schedule strategy and implementation of image mosaicking parallelization. Finally, the key problems and future potential research directions for image mosaicking are addressed
The Effect of Economic Policy Uncertainty on Bank Valuations
This paper examines how economic policy uncertainty (EPU) affects bank valuations. Using a large sample of banks over a long period, we find that EPU has a negative effect on bank valuations. One explanation for this result is that EPU reduces bank loan growth, and lower loan growth then leads to lower bank valuations. Consistent with this explanation, we find that the negative effect of EPU is more pronounced for banks with a higher ratio of loans to total assets
Nanophotonic soliton-based microwave synthesizers
Microwave photonic technologies, which upshift the carrier into the optical
domain to facilitate the generation and processing of ultrawide-band electronic
signals at vastly reduced fractional bandwidths, have the potential to achieve
superior performance compared to conventional electronics for targeted
functions. For microwave photonic applications such as filters, coherent
radars, subnoise detection, optical communications and low-noise microwave
generation, frequency combs are key building blocks. By virtue of soliton
microcombs, frequency combs can now be built using CMOS compatible photonic
integrated circuits, operated with low power and noise, and have already been
employed in system-level demonstrations. Yet, currently developed photonic
integrated microcombs all operate with repetition rates significantly beyond
those that conventional electronics can detect and process, compounding their
use in microwave photonics. Here we demonstrate integrated soliton microcombs
operating in two widely employed microwave bands, X- and K-band. These devices
can produce more than 300 comb lines within the 3-dB-bandwidth, and generate
microwave signals featuring phase noise levels below 105 dBc/Hz (140 dBc/Hz) at
10 kHz (1 MHz) offset frequency, comparable to modern electronic microwave
synthesizers. In addition, the soliton pulse stream can be injection-locked to
a microwave signal, enabling actuator-free repetition rate stabilization,
tuning and microwave spectral purification, at power levels compatible with
silicon-based lasers (<150 mW). Our results establish photonic integrated
soliton microcombs as viable integrated low-noise microwave synthesizers.
Further, the low repetition rates are critical for future dense WDM channel
generation schemes, and can significantly reduce the system complexity of
photonic integrated frequency synthesizers and atomic clocks
Minimal Turing Test and Children's Education
Considerable evidence proves that causal learning and causal understanding greatly enhance our ability to manipulate the physical world and are major factors that distinguish humans from other primates. How do we enable unintelligent robots to think causally, answer the questions raised with "why" and even understand the meaning of such questions? The solution is one of the keys to realizing artificial intelligence. Judea Pearl believes that to achieve human-like intelligence, researchers must start by imitating the intelligence of children, so he proposed a "causal inference engine" to help future artificial intelligence make causal inference, pass the Minimal Turing Test, and even become a moral subject who can discern good from evil. This study attempts to provide some insights into the development of children's education from basic assumptions and construction goals of artificial intelligence, and to reflect on the causal model of artificial intelligence through children's education
Diagnosis and phylogenetic analysis of Orf virus from goats in China: a case report
<p>Abstract</p> <p>Background</p> <p>Orf virus (ORFV) is the etiological agent of contagious pustular dermatitis and is the prototype of the genus Parapoxvirus (PPV). It causes a severe exanthematous dermatitis that afflicts domestic and wild small ruminants.</p> <p>Case presentation</p> <p>In the present study, an outbreak of proliferative dermatitis in farmed goats. The presence of ORFV in tissue scrapings from the lips was confirmed by B2L gene polymerase chain reaction (PCR) amplification. The molecular characterization of the ORFV was performed using PCR amplification, DNA sequencing and phylogenetic analysis of the B2L gene.</p> <p>Conclusion</p> <p>The results of this investigation indicated that the outbreak was caused by infection with an ORFV that was closely related genetically to Nantou (DQ934351), which was isolated from the Tai wan province of China and Hoping (EU935106), which originated from South Korea in 2008. This is the first report of the phylogenetic analysis of ORFV from goats in China.</p
Analysis of pig serum proteins based on shotgun liquid chromatography-tandem mass spectrometry
Recent advances in proteomics technologies have opened up significant opportunities for future applications. We used shotgun liquid chromatography, coupled with tandem mass spectrometry (LC-MS/MS) to determine the proteome profile of healthy pig serum. Samples of venous blood were collected and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis separation and in-gel trypsin digestion. The peptides were then processed using shotgun LC-MS/MS. Serum proteins were subjected to protein identification and bioinformatics analysis. A total of 392 proteins were identified, and 179 were annotated according to their molecular functions and biological processes, excluding 142 hypothetical proteins and 71 immune globulins. To the best of our knowledge, this represents the first porcine serum proteomics analysis based on shotgun LC-MS/MS. This method and the resulting proteomics information may prove valuable for ensuring good animal welfare practice and for monitoring swine health and disease status.Keywords: Analysis, pig serum, shotgun coupled with tandem mass spectrometry (LC-MS/MS
Utility of intra-procedural cone-beam computed tomography imaging for the determination of the artery of Adamkiewicz suspected by angiography during transarterial embolization for hemoptysis
PURPOSETo evaluate the role of cone-beam computed tomography (CT) performed for the determination of the artery of Adamkiewicz (AKA) suspected by angiography during trans-catheter bronchial artery embolization for hemoptysis.METHODSIn this retrospective study, 17 patients with hemoptysis who underwent cone-beam CT for evaluation of the AKA prior to arterial embolization from December 2014 to March 2022 were included. During the angiographic session, two interventional radiologists selected the possible AKAs that were defined as obscured hairpin-curved vessels arising from the dorsal branch of the intercostal arteries and running towards the midline in the arterially enhanced phase. Contrast-enhanced cone-beam CT was performed as an adjunct to angiography to determine whether the indefinite AKA was a real AKA based on whether it was found to connect to the anterior spinal artery.RESULTSSelective cone-beam CT was performed at 17 possible AKAs detected by selective arteriogram of the intercostal artery (ICA). Cone-beam CT allowed for the determination of AKAs in 16 cases (94.1%). As a result of cone-beam CT findings, 9 of 16 study arteries (56.3%) were judged as definite AKAs, and the remaining 7 (43.7%) were judged as definitely not AKAs but as the musculocutaneous branching from the dorsal branch of the ICA. In 1 of 17 cases (5.9%), cone-beam CT could not determine the AKA because of poor image quality caused by inadequate breath holding. An additional anterior radiculomedullary artery arising from the dorsal branch of the lower ICA because of the inflow of the contrast medium through the anastomosis was detected in one case by conebeam CT but not by angiography.CONCLUSIONIntraprocedural enhanced cone-beam CT performed as an adjunctive technique to angiography is sufficient for confident determination of the AKA, which is essential for the operators to perform accurate and safe arterial embolization for hemoptysis
High-yield wafer-scale fabrication of ultralow-loss, dispersion-engineered silicon nitride photonic circuits
Low-loss photonic integrated circuits (PIC) and microresonators have enabled
novel applications ranging from narrow-linewidth lasers, microwave photonics,
to chip-scale optical frequency combs and quantum frequency conversion. To
translate these results into a widespread technology, attaining ultralow
optical losses with established foundry manufacturing is critical. Recent
advances in fabrication of integrated Si3N4 photonics have shown that
ultralow-loss, dispersion-engineered microresonators can be attained at
die-level throughput. For emerging nonlinear applications such as integrated
travelling-wave parametric amplifiers and mode-locked lasers, PICs of length
scales of up to a meter are required, placing stringent demands on yield and
performance that have not been met with current fabrication techniques. Here we
overcome these challenges and demonstrate a fabrication technology which meets
all these requirements on wafer-level yield, performance and length scale.
Photonic microresonators with a mean Q factor exceeding 30 million,
corresponding to a linear propagation loss of 1.0 dB/m, are obtained over full
4-inch wafers, as determined from a statistical analysis of tens of thousands
of optical resonances and cavity ringdown with 19 ns photon storage time. The
process operates over large areas with high yield, enabling 1-meter-long spiral
waveguides with 2.4 dB/m loss in dies of only 5x5 mm size. Using a modulation
response measurement self-calibrated via the Kerr nonlinearity, we reveal that,
strikingly, the intrinsic absorption-limited Q factor of our Si3N4
microresonators exceeds a billion. Transferring the present Si3N4 photonics
technology to standard commercial foundries, and merging it with silicon
photonics using heterogeneous integration technology, will significantly expand
the scope of today's integrated photonics and seed new applications
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