3,276 research outputs found
Investigation of Detonative Combustion Characteristics
AbstractThe pressure and deflagration-to-detonation transition (DDT) characteristics of acetylene and oxygen flame were studied in a detonation tube. The pressure history and the flame velocity along the tube were measured with high frequency pressure transducers and ion probes. By analyzing the data recorded in the experiment, the detonation wave pressure, post-wave pressure and DDT distance were obtained, together with the effects of the initial pressure varying from 2 104 Pa to 105 Pa, equivalence ration from 0.3 to 1.0, and mixture concentration from 60% to 100%. It was found that the detonation pressure was decreased respectively with the decrease of initial pressure, equivalence ratio and mixture concentration, but the DDT distance was enlarged. The DDT distance was found particularly sensitive to mixture concentration
Research on a Model of Extracting Persons\u27 Information Based on Statistic Method and Conceptual Knowledge
PACLIC 21 / Seoul National University, Seoul, Korea / November 1-3, 200
Clinical Characteristics of Recurrent Nasopharyngeal Carcinoma in High-Incidence Area
Background. To describe the clinical characteristics of the patients who suffered from relapse after conventional irradiation for nasopharyngeal carcinoma (NPC). Methods. Three hundred and fifty-one consecutive patients with first-time recurrent NPC between January 1999 and July 2005 were included. The patients' clinical data were reviewed, including recurrent interval time, symptoms, signs, imaging characteristics, pathologic features, and restaging. Results. The median interval of relapse was 26.0 months. The most common symptoms in symptomatic patients were nasal bloody discharge (37.9%) and headache (31.1%). Local recurrence alone accounted for 73.5%. Most patients were restaged as stage III (23.1%) and stage IV (51.1%). Subgroup analysis suggested a significantly higher proportion of the long-latent relapses originated from early primary. A series of postreirradiation complications were more frequent in patients with longer latency at reception. Conclusions. Most recurrent nasopharyngeal carcinoma is advanced disease. Patients with different recurrent interval time show different nature behavior
Chimeric antigen receptor-modified T cells for the immunotherapy of patients with EGFR-expressing advanced relapsed/refractory non-small cell lung cancer
Model Spider: Learning to Rank Pre-Trained Models Efficiently
Figuring out which Pre-Trained Model (PTM) from a model zoo fits the target
task is essential to take advantage of plentiful model resources. With the
availability of numerous heterogeneous PTMs from diverse fields, efficiently
selecting the most suitable PTM is challenging due to the time-consuming costs
of carrying out forward or backward passes over all PTMs. In this paper, we
propose Model Spider, which tokenizes both PTMs and tasks by summarizing their
characteristics into vectors to enable efficient PTM selection. By leveraging
the approximated performance of PTMs on a separate set of training tasks, Model
Spider learns to construct tokens and measure the fitness score between a
model-task pair via their tokens. The ability to rank relevant PTMs higher than
others generalizes to new tasks. With the top-ranked PTM candidates, we further
learn to enrich task tokens with their PTM-specific semantics to re-rank the
PTMs for better selection. Model Spider balances efficiency and selection
ability, making PTM selection like a spider preying on a web. Model Spider
demonstrates promising performance in various configurations of model zoos
Capturing Delayed Feedback in Conversion Rate Prediction via Elapsed-Time Sampling
Conversion rate (CVR) prediction is one of the most critical tasks for
digital display advertising. Commercial systems often require to update models
in an online learning manner to catch up with the evolving data distribution.
However, conversions usually do not happen immediately after a user click. This
may result in inaccurate labeling, which is called delayed feedback problem. In
previous studies, delayed feedback problem is handled either by waiting
positive label for a long period of time, or by consuming the negative sample
on its arrival and then insert a positive duplicate when a conversion happens
later. Indeed, there is a trade-off between waiting for more accurate labels
and utilizing fresh data, which is not considered in existing works. To strike
a balance in this trade-off, we propose Elapsed-Time Sampling Delayed Feedback
Model (ES-DFM), which models the relationship between the observed conversion
distribution and the true conversion distribution. Then we optimize the
expectation of true conversion distribution via importance sampling under the
elapsed-time sampling distribution. We further estimate the importance weight
for each instance, which is used as the weight of loss function in CVR
prediction. To demonstrate the effectiveness of ES-DFM, we conduct extensive
experiments on a public data and a private industrial dataset. Experimental
results confirm that our method consistently outperforms the previous
state-of-the-art results.Comment: This paper has been accepted by AAAI 202
Ring structure amino acids affect the suppressor activity of melon aphid-borne yellows virus P0 protein
AbstractMelon aphid-borne yellows virus (MABYV) is a newly identified polerovirus occurring in China. Here, we demonstrate that the MABYV encoded P0 (P0MA) protein is a strong suppressor of post-transcriptional gene silencing (PTGS) with activity comparable to tobacco etch virus (TEV) HC-Pro. In addition we have shown that the LP F-box motif present at the N-terminus of P0MA is required for suppressor activity. Detailed mutational analyses on P0MA revealed that changing the conserved Trp 212 with non-ring structured amino acids altered silencing suppressor functions. Ala substitutions at positions 12 and 211 for Phe had no effect on P0 suppression-activity, whereas Arg and Glu substitutions had greatly decreased suppressor activity. Furthermore, substitutions targeting Phe at position 30 also resulted in reduced P0 suppression-activity. Altogether, these results suggest that ring structured Trp/Phe residues in P0 have important roles in suppressor activity
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