285 research outputs found

    A Content-Adaptive Side Information Generation Method for Distributed Video Coding

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    AbstractIn this paper, a content-adaptive method to generate side information at the block level is presented. First, motion compensated temporal interpolation (MCTI) algorithm is used between the reconstructed key frames at the decoder to acquire initial motion vectors. Second, the image is segmented and the edge of moving region is detected by obtained the residual frame between two consecutive key frames. Furthermore, hierarchical motion estimation (HME) and motion vector filter (MVF) are adopted for edge region and an adaptive motion vector filter (AMVF) is introduced in non-edge region to correct the false estimated motion vectors. The proposal is tested and compared with the results of the state-of-the-art DISCOVER codec and RD improvements on the set of test sequences are observed

    Deep Drawing of Cylindrical Cup Using Incremental Electromagnetic Assisted Stamping with Radial Magnetic Pressure

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    AbstractA new forming method named incremental electromagnetic assisted stamping with radial magnetic pressure is proposed to draw a deep cylindrical cup. The method combines with traditional stamping, electromagnetic sheet forming and electromagnetic launch technology. Three types of discharge coils are imbedded in die and blank holder, respectively. The 3D finite element model is set up to predict the complex deformation process. The forming process and principle of the new method are discussed. The values of material flow, stress and thickness in different forming processes are compared. In comparison with traditional stamping, incremental electromagnetic assisted stamping with radial magnetic pressure can significantly increase the value of material at sheet end flow inward, decrease the tensile stress and thickness reduction at the easily broken position, and obtain uniform stress distribution. Therefore, deeper cylindrical cup could be manufactured by incremental electromagnetic assisted stamping with radial magnetic pressure

    Gas venting that bypasses the feather edge of marine hydrate, offshore Mauritania

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    Methane can be released from the vast marine hydrate reservoirs that surround continents into oceans and perhaps the atmosphere. But how these pathways work within the global carbon cycle now and during a warmer world is only partially understood. Here we use 3-D seismic data to identify what we interpret to be a gas venting system that bypasses the hydrate stability zone (HSZ) offshore of Mauritania. This venting is manifested by the presence of the acoustic wipe-out (AWO) across a densely faulted succession above a salt diapir and a set of morphological features including a substantial, ∼260 m wide and ∼32 m deep, pockmark at the seabed. The base of the HSZ is marked by a bottom simulating reflector (BSR) which deflects upwards above the diapir, rather than mimicking the seabed. We use a numerical modelling to show that this deflection is caused by the underlying salt diapir. It creates a trapping geometry for gas sealed by hydrate-clogged sediment. After entering the HSZ, some methane accumulated as hydrate in the levees of a buried canyon. Venting in this locality probably reduces the flux of gas to the landward limit of feather edge of hydrate, reducing the volume of gas that would be susceptible for release during a warmer world

    Fault diagnosis of rolling bearing based on improved CEEMDAN and distance evaluation technique

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    In order to accurately identify the fault conditions of rolling bearing, this paper presents a fault diagnosis method based on improved complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and distance evaluation technique. In this method, to effectively extract potential fault-related information, vibration signals of rolling bearing in different fault conditions are decomposed into a set of intrinsic mode functions (IMFs) through improved CEEMDAN. The first eight IMFs containing most fault information are selected for extracting fault features. The original feature set is obtained including energy values, singular values and envelope sample entropy values. Then distance evaluation technique is implemented for selecting sensitive feature set and discarding irrelevant or redundant features. Subsequently, the sensitive feature set is fed into support vector machine (SVM) for automatically identifying rolling bearing fault conditions. The simulation results demonstrate that improved CEEMDAN is able to solve the problem of mode mixing and achieve a numerically negligible reconstruction error. Meanwhile experimental consequences indicate that the proposed method can acquire higher identification accuracy, as well as reduce the classifier computational burden

    The Airlines’ Recent Experience Under the Railway Labor Act

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    Silky-feather has been selected and fixed in some breeds due to its unique appearance. This phenotype is caused by a single recessive gene (hookless, h). Here we map the silky-feather locus to chromosome 3 by linkage analysis and subsequently fine-map it to an 18.9 kb interval using the identical by descent (IBD) method. Further analysis reveals that a C to G transversion located upstream of the prenyl (decaprenyl) diphosphate synthase, subunit 2 (PDSS2) gene is causing silky-feather. All silky-feather birds are homozygous for the G allele. The silky-feather mutation significantly decreases the expression of PDSS2 during feather development in vivo. Consistent with the regulatory effect, the C to G transversion is shown to remarkably reduce PDSS2 promoter activity in vitro. We report a new example of feather structure variation associated with a spontaneous mutation and provide new insight into the PDSS2 function

    Effects of Deformation Rate on Ductility of Ti-6Al-4V Material

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    AbstractTo determine the velocity field in which the Ti-6Al-4V titanium alloy sheet was sensitive to the strain rate, the formability at different strain rates were tested using a ring sample in the electromagnetic ring expansion experiment. For the test of titanium alloy, an aluminum alloy loop was used as a driver ring due to improve energy efficiency. The expansion velocity and strain rate of titanium ring were predicted by a numerical simulation method which had been verified by experimental data obtained with a high speed camera. The uniform strain was defined as the ratio of the change and the one after expansion of the cross sectional area in this study. Since the fracture strain of a material was related to the aspect ratio (ratio of length to diameter) of samples, the uniform strain was chosen to characterize the ductility of the material. The results indicate that when the tensile speed of Ti-6Al-4V titanium alloy sample is 2mm/min (quasi-static), the strain rate of deformation is 6.67×10-4 1/s and its uniform strain (ɛu) reaches 0.102. Instead, the uniform strain is only 0.032 when the expanding speed of 46.7 m/s is faster than the quasi-static speed. However, the uniform strain increases proportionally with the increment of the strain rate, and exceeds the quasi-static uniform strain reaching 0.11 or more when the deformation speed is faster than 286 m/s, in which the strain rate exceeded 6935.6/s. Therefore, the deformation speed of 286 m/s or the strain rate of 6935.6 1/s could be considered as the threshold to improve the ductility of Ti-6Al-4V titanium alloy

    Different water and nitrogen level effects on soil microbial properties of spinach

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    Understanding the interactions of plant soil environment and rhizosphere microbial changes are necessary to develop new strategies for the sustainable agriculture. A field experiment with combination of three water levels and three nitrogen rates was conducted to investigate the effect of water and nitrogen management on the changes of soil microbial properties in non-rhizosphere and rhizosphere soils of spinach. Non-Rhizosphere and rhizosphere microbial diversities were affected by water and nitrogen applications. Evenness index in the no-nitrogen treatment was more than that of 85 and 170 kg ha–1 nitrogen treatments in the non-rhizosphere or rhizosphere soil. Microbial biomass carbon in non-rhizosphere soil or rhizosphere soil decreased with the increase of nitrogen application, but showed the highest value in 16.5% of soil water content, followed by 12.5% and 20.5% of soil water content. Soil microbial biomass phosphorus content of 85 kg ha–1 nitrogen treatment in the non-rhizosphere soil or rhizosphere soil was significantly different for 0 and 170 kg ha–1 nitrogen treatments. Nitrification rate increased with the increase of soil water content in 0 and 170 kg ha–1 treatments. Our results demonstrated that water and nitrogen could impact the soil fertility and microbial activity of spinach

    Review of rehabilitation protocols for brachial plexus injury

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    Brachial plexus injury (BPI) is one of the most serious peripheral nerve injuries, resulting in severe and persistent impairments of the upper limb and disability in adults and children alike. With the relatively mature early diagnosis and surgical technique of brachial plexus injury, the demand for rehabilitation treatment after brachial plexus injury is gradually increasing. Rehabilitation intervention can be beneficial to some extent during all stages of recovery, including the spontaneous recovery period, the postoperative period, and the sequelae period. However, due to the complex composition of the brachial plexus, location of injury, and the different causes, the treatment varies. A clear rehabilitation process has not been developed yet. Rehabilitation therapy that has been widely studied focusing on exercise therapy, sensory training, neuroelectromagnetic stimulation, neurotrophic factors, acupuncture and massage therapy, etc., while interventions like hydrotherapy, phototherapy, and neural stem cell therapy are less studied. In addition, rehabilitation methods in some special condition and group often neglected, such as postoperative edema, pain, and neonates. The purpose of this article is to explore the potential contributions of various methods to brachial plexus injury rehabilitation and to provide a concise overview of the interventions that have been shown to be beneficial. The key contribution of this article is to form relatively clear rehabilitation processes based on different periods and populations, which provides an important reference for the treatment of brachial plexus injuries
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