Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 4 Articles
This work presents a no-reference image sharpness metric based on human blur perception for JPEG2000 compressed image.\nThe metric mainly uses a ringing measure. And a blurring measure is used for compensation when the blur is so severe that\nringing artifacts are concealed.We used the anisotropic diffusion for the preliminary ringingmap and refined it by considering the\nproperty of ringing structure.The ringing detection of the proposed metric does not depend on edge detection, which is suitable\nfor high degraded images. The characteristics of the ringing and blurring measures are analyzed and validated theoretically and\nexperimentally. The performance of the proposed metric is tested and compared with that of some existing JPEG2000 sharpness\nmetrics on three widely used databases.Theexperimental results showthat the proposed metric is accurate and reliable in predicting\nthe sharpness of JPEG2000 images....
Two-dimensional photonic crystal (2D PhC) waveguides with square lattice composed of dielectric rhombic cross-section elements\nin air background, by using plane wave expansion (PWE) method, are investigated. In order to study the change of photonic band\ngap (PBG) by changing of elongation of elements, the band structure of the used structure is plotted. We observe that the size of\nthe PBG changes by variation of elongation of elements, but there is no any change in themagnitude of defect modes. However, the\nused structure does not have any TE defect modes but it has TM defect mode for any angle of elongation. So, the used structure\ncan be used as optical polarizer....
Solution searching devices that operate on the basis of controlling the spatiotemporal dynamics of excitation transfer via\ndressed photon interactions between quantum dots have been proposed. Long-range excitation transfer based on dressed photon\ninteractions between randomly distributed quantumdots is considered to be effective in realizing such devices.Here,we successfully\ncontrolled the spatiotemporal dynamics of excitation transfer using a Y-junction structure consisting of randomly dispersed\nCdSe/ZnS core-shell quantum dots. This Y-junction structure has two ââ?¬Å?output endsââ?¬Â and one ââ?¬Å?tap end.ââ?¬Â By exciting one output\nend with control light, we observed increased excitation transfer to the other output end via a state-filling effect. Conversely, we\nobserved reduced excitation transfer to the output ends by irradiating the tap end with control light, due to excitation of defect\nlevels in the tap end. These results show the possibility of controlling the optical excitation transfer dynamics between multiple\nquantum dots....
The advantages of Ethernet passive optical network (EPON) are setting it to be a natural ubiquitous solution for the access network.\nIn the upstream direction of EPON, the directional property of the splitter requires that the traffic flow be mitigated to avoid\ncollision. A dynamic bandwidth allocation (DBA) scheme is desirable in optimizing the bandwidth usage further. In this paper, a\nglobal priority DBAmechanism is discussed.The mechanism aims to reduce the overall delay while enhancing the throughput and\nfairness. This study was conducted using MATLAB where it was compared to two other algorithms in the literature. The results\nshow that the delay is reduced up to 59% and the throughput and fairness index are improved up to 10% and 6%, respectively....
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