20,366 research outputs found
Unequal Error Protected JPEG 2000 Broadcast Scheme with Progressive Fountain Codes
This paper proposes a novel scheme, based on progressive fountain codes, for
broadcasting JPEG 2000 multimedia. In such a broadcast scheme, progressive
resolution levels of images/video have been unequally protected when
transmitted using the proposed progressive fountain codes. With progressive
fountain codes applied in the broadcast scheme, the resolutions of images (JPEG
2000) or videos (MJPEG 2000) received by different users can be automatically
adaptive to their channel qualities, i.e. the users with good channel qualities
are possible to receive the high resolution images/vedio while the users with
bad channel qualities may receive low resolution images/vedio. Finally, the
performance of the proposed scheme is evaluated with the MJPEG 2000 broadcast
prototype
Rateless Codes with Progressive Recovery for Layered Multimedia Delivery
This paper proposes a novel approach, based on unequal error protection, to
enhance rateless codes with progressive recovery for layered multimedia
delivery. With a parallel encoding structure, the proposed Progressive Rateless
codes (PRC) assign unequal redundancy to each layer in accordance with their
importance. Each output symbol contains information from all layers, and thus
the stream layers can be recovered progressively at the expected received
ratios of output symbols. Furthermore, the dependency between layers is
naturally considered. The performance of the PRC is evaluated and compared with
some related UEP approaches. Results show that our PRC approach provides better
recovery performance with lower overhead both theoretically and numerically
Isolation and Identification of Endophytic Fungi from Actinidia macrosperma and Investigation of Their Bioactivities
Endophytic fungi from the Chinese medicinal plant Actinidia macrosperma were isolated and identified for the first time. This was the first study to evaluate their cytotoxic and antitumour activities against brine shrimp and five types of tumour cells, respectively. In total, 17 fungal isolates were obtained. Five different taxa were represented by 11 isolates, and six isolates were grouped into the species of Ascomycete Incertae sedis with limited morphological and molecular data. Cytotoxic activity has been found in most isolates except AM05, AM06, and AM10. The isolates AM07 (4.86 μg/mL), AM11 (7.71 μg/mL), and AM17 (14.88 μg/mL) exhibited significant toxicity against brine shrimp. The results of the MTT assay to assess antitumour activity revealed that 82.4% of isolate fermentation broths displayed growth inhibition (50% inhibitory concentration IC50< 100 μg/mL). Moreover, AM07, AM11, and AM17 showed strong antitumour activity in all the cell lines examined. These results suggest that endophytic fungi in A. macrosperma are valuable for the isolation and identification of novel cytotoxic and antitumour bioactive agents
Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique
Alternating current field measurement (ACFM) testing is one of the promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach was proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the center of the excitation coil where the magnetic field is measured. It was found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack followed a sine wave shape. A customized accelerated finite element method solver programmed in MATLAB was adopted to simulate the performance of the designed sensor probe which could significantly improve the computation efficiency due to the small crack perturbation. The experiments were also carried out to validate the simulations. It was found that the ratio between the z and x components of the magnetic field remained stable under various rotation angles. It showed the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique
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