354 research outputs found
On file-based content distribution over wireless networks via multiple paths: Coding and delay trade-off
With the emergence of the adaptive bit rate (ABR) streaming technology, the video/content streaming technology is shifting toward a file-based content distribution. That is, video content is encoded into a set of smaller media files containing video of 2-10 seconds before transmission. This file-based content distribution, coupled with increasingly rapid adoption of smartphones, requires an efficient file-based distribution algorithm to satisfy the QoS demand in wireless networks. In this paper, we study the transmission of a finite-sized file over wireless networks using multipath routing, with the objective to minimize file transmission delay instead of average packet delay. The file transmission delay is defined as the time interval from the instant that a file is first transmitted to the time at which the file can be reconstructed in the destination node. We observe that file transmission delay depends not only on the mean of the packet delay but also on its distribution, especially the tail. This observation leads to a better understanding of the file transfer delay in wireless networks and a minimum delay file transmission strategy. In a wireless multipath communication scenario, we propose to use packet level erasure code (e.g., digital fountain code) to transmit data file with redundancy. Given that a file with k packets is encoded into n packets for transmission, the use of digital fountain code allows the file to be received when only k out of n packets are received. By adding redundant packets, the destination node does not have to wait for the packet to arrive late, hence reducing the delay of the file transmission. We characterize the tradeoff between the code rate (i.e., the ratio of the number of transmitted packets to the number of the original packets) and the file delay reduction. As a rule of thumb, we provide practical guidelines in determining an appropriate code rate for a fixed file to achieve a reasonable transmission delay. We show that only- - a few redundant packets are needed to achieve a significant reduction in file transmission delay
Size and temperature effects on the viscosity of water inside carbon nanotubes
The influences of the diameter (size) of single-walled carbon nanotubes (SWCNTs) and the temperature on the viscosity of water confined in SWCNTs are investigated by an "Eyring-MD" (molecular dynamics) method. The results suggest that the relative viscosity of the confined water increases with increasing diameter and temperature, whereas the size-dependent trend of the relative viscosity is almost independent of the temperature. Based on the computational results, a fitting formula is proposed to calculate the size- and temperature- dependent water viscosity, which is useful for the computation on the nanoflow. To demonstrate the rationality of the calculated relative viscosity, the relative amount of the hydrogen bonds of water confined in SWCNTs is also computed. The results of the relative amount of the hydrogen bonds exhibit similar profiles with the curves of the relative viscosity. The present results should be instructive for understanding the coupling effect of the size and the temperature at the nanoscale
Improving yield and water use efficiency of apple trees through intercrop-mulch of crown vetch (Coronilla varia L.) combined with different fertilizer treatments in the Loess Plateau
Improving water use efficiency (WUE) and soil fertility is relevant for apple production in drylands. The effects of intercrop-mulch (IM) of crown vetch (Coronilla varia L.) combined with different fertilizer treatments on WUE of apple trees and soil fertility of apple orchards were assessed over three years (2011, 2013 and 2014). A split-plot design was adopted, in which the main treatments were IM and no intercrop-mulch (NIM). Five sub-treatments were established: no fertilization (CK); nitrogen and phosphorus fertilizer (NP); manure (M); N, P and potassium fertilizer (NPK); and NPK fertilizer combined with manure (NPKM). Due to mowing and mulching each month during July–September, the evapotranspiration for IM was 17.3% lower than that of NIM in the dry year of 2013. Additionally, the soil water storage of NPKM treatment was higher than that of CK during the experimental period. Thus, single fruit weight and fruit number per tree increased with IM and NPKM application. Moreover, applying NPKM with IM resulted in the highest yield (on average of three years), which was 73.25% and 130.51% greater than that of CK in IM and NIM, respectively. The WUE of NPKM combined with IM was also the highest in 2013 and 2014 (47.69 and 56.95% greater than applying IM alone). In addition, due to application of IM combined with NPKM, soil organic matter was increased by 25.8% compared with that of CK (in NIM). Additionally, application of IM combined with NPKM obtained more economic net return, compared to other combinations. Therefore, applying NPKM with IM is recommended for improving apple production in this rain-fed agricultural area
Unilateral pedicle screws asymmetric tethering: an innovative method to create idiopathic deformity
<p>Abstract</p> <p>Objective</p> <p>To evaluate the feasibility of the method that unilateral pedicle screws asymmetric tethering in concave side in combination with convex rib resection for creating idiopathic deformity.</p> <p>Summary of background data</p> <p>Various methods are performed to create idiopathic deformity. Among these methods, posterior asmmetric tethering of the spine shows satisfying result, but some drawbacks related to the current posterior asymmetric tether were still evident.</p> <p>Materials and methods</p> <p>Unilateral pedicle screws asymmetric tethering was performed to 14 female goats (age: 5–8 week-old, weight: 6–8 kg) in concave side in combination with convex rib resection. Dorsoventral and lateral plain radiographs were taken of each thoracic spine in the frontal and sagittal planes right after the surgery and later every 4 weeks.</p> <p>Results</p> <p>All animals ambulated freely after surgery. For technical reasons, 2 goats were excluded (one animal died for anesthetic during the surgery, and one animal was lost for instrumental fail due to postoperative infection). Radiography showed that 11 goats exhibited scoliosis with convex toward to the right side, and as the curve increased with time, only 1 goat showed nonprogressive. The initial scoliosis generated in the progressors after the procedures measured 29.0° on average (range 23.0°–38.5°) and increased to 43.0° on average (range 36.0°–58.0°) over 8 to 10 weeks. The average progression of 14.0° was measured. The curvature immediately after tethering surgery (the initial Cobb angle) did have a highly significant correlation with the final curvature (p < 0.001). The progressive goats showed an idiopathic-like deformity not only by radiography, but in general appearance.</p> <p>Conclusion</p> <p>Unilateral pedicle screws asymmetric tethering is a practical method to create experimental scoliosis, especially for those who would like to study the correction of this deformity.</p
The Comparison of Information Systems Develop Trends between the Chinese Mainland and International
The aims of this research are two fold. First, it compares the research focus of Information Systems in Mainland China with that of the international IS research community. Second, the paper describes the main features and trend of IS research in Mainland China, and makes some suggestions as to some possible interesting research arena. The data are from twenty five academic journals in China and proceedings of international Information Systems conferences
NoiseDiffusion: Correcting Noise for Image Interpolation with Diffusion Models beyond Spherical Linear Interpolation
Image interpolation based on diffusion models is promising in creating fresh
and interesting images. Advanced interpolation methods mainly focus on
spherical linear interpolation, where images are encoded into the noise space
and then interpolated for denoising to images. However, existing methods face
challenges in effectively interpolating natural images (not generated by
diffusion models), thereby restricting their practical applicability. Our
experimental investigations reveal that these challenges stem from the
invalidity of the encoding noise, which may no longer obey the expected noise
distribution, e.g., a normal distribution. To address these challenges, we
propose a novel approach to correct noise for image interpolation,
NoiseDiffusion. Specifically, NoiseDiffusion approaches the invalid noise to
the expected distribution by introducing subtle Gaussian noise and introduces a
constraint to suppress noise with extreme values. In this context, promoting
noise validity contributes to mitigating image artifacts, but the constraint
and introduced exogenous noise typically lead to a reduction in signal-to-noise
ratio, i.e., loss of original image information. Hence, NoiseDiffusion performs
interpolation within the noisy image space and injects raw images into these
noisy counterparts to address the challenge of information loss. Consequently,
NoiseDiffusion enables us to interpolate natural images without causing
artifacts or information loss, thus achieving the best interpolation results.Comment: ICLR 202
Kibra Functions as a Tumor Suppressor Protein that Regulates Hippo Signaling in Conjunction with Merlin and Expanded
SummaryThe Hippo signaling pathway regulates organ size and tissue homeostasis from Drosophila to mammals. Central to this pathway is a kinase cascade wherein Hippo (Hpo), in complex with Salvador (Sav), phosphorylates and activates Warts (Wts), which in turn phosphorylates and inactivates the Yorkie (Yki) oncoprotein, known as the YAP coactivator in mammalian cells. The FERM domain proteins Merlin (Mer) and Expanded (Ex) are upstream components that regulate Hpo activity through unknown mechanisms. Here we identify Kibra as another upstream component of the Hippo signaling pathway. We show that Kibra functions together with Mer and Ex in a protein complex localized to the apical domain of epithelial cells, and that this protein complex regulates the Hippo kinase cascade via direct binding to Hpo and Sav. These results shed light on the mechanism of Ex and Mer function and implicate Kibra as a potential tumor suppressor with relevance to neurofibromatosis
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