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21.
The need to measure video quality arises in the development of video equipment and in the delivery and storage of video and image information. In this paper, we propose a new perceptually significant video quality metric to estimate the effect of block coding for standards H.264 AVC and MPEG2. Our method operates in the spatial domain and does not require a high complexity of computation. We evaluate the performance of the proposed method by using three sequences CIF ‘common intermediate file’ with different compression rate. We compare it with Suthaharan’s and MSU’s techniques by using ‘LIVE’ and ‘IVP’ databases. Results indicate that the proposed method outperforms Suthaharan’s and MSU techniques in H264 coder. They also indicate that our method is more effective than MSU’s and Suthaharan’s techniques for the H.264 AVC standards with the Spearman Rank Order Correlation Coefficient.  相似文献   
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A family of space-time codes suited for noncoherent multi-input multi-output (MIMO) systems is presented. These codes use all the complex degrees of freedom of the system, i.e. M/spl times/(1-(M/T)) symbols per channel use. They are constructed as codes on the Grassmann manifold G/sub T,M/(/spl Copf/) where T is the temporal codelength and M is the number of transmit antennas.  相似文献   
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The use of fiber bronchoscopy (FBS) for early diagnosis of aspiration in patients with grave craniocerebral (CCI) and combined injury is analyzed. Aspiration is not always associated with a clear-cut clinical picture in this cohort of patients, and x-ray examination of thoracic organs during the first hours after the injury is ineffective. High diagnostic potentials of BFS and possibility of removing the contents from the tracheobronchial tree under visual control dictate this measure for all cases with grave CCI and combined injuries during the first hours of hospitalization.  相似文献   
26.
A 14-year-old girl developed skin rash, fever and dyspnea. The chest roentgenogram showed diffuse reticulonodular infiltration. Pulmonary function tests revealed mild restrictive defect and blood oxygen pressure at 71 mm Hg. BAL showed increased cell counts with lymphocytosis at 15% and neutrophilia at 3%. Outcome was good after carbamazepine withdrawal and without corticosteroid therapy. Relapse was observed after patient-induced rechallenge.  相似文献   
27.
Digital image watermarking is still a new field for research. In fact, digital watermarking is the best tool for the copyright protection and the authentication of the digital data. Researches are interested in the tradeoff that exists between the insertion capacity, the imperceptibility, and the robustness. The embedding function has a great influence on these characteristics. Channel coding techniques are used to reduce the error probability of the hidden watermark. On the other hand, the watermark strength is adapted according to human visual perception. In this article, we present a new scheme to achieve the embedding function in the framework of a robust and nonblind watermarking in multiresolution field by 9/7 wavelet of Daubechies. Indeed, we replace the constant embedding strength by a variable coefficient based on the logarithmic function. This coefficient is adaptive according to the magnitude of the wavelet transform magnitude that will be watermarked. This adaptive scheme reduces the computational error and enhances the robustness and the imperceptibility. Experimental results are presented to show that our scheme gives a better correlation and an improved PSNR. They demonstrate that the detection is enhanced. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 249–257, 2006  相似文献   
28.
This paper presents a new model and an experimental investigation of the elastic–plastic flow until failure in short-fiber reinforced thermoplastics typically produced by injection molding. The distribution of fiber orientations and lengths is reproduced statistically within a representative volume element (RVE) of the composite microstructure. Then, the RVE is decomposed fictitiously into pseudo-grains (PGs) inside of which the fiber orientation and aspect ratio are unique. An incremental Mori–Tanaka model is used to predict the phase averages of the stresses and strains inside each PG. Damage intervenes in a second homogenization step: the macroscopic stress accounts for the fact that PGs fail one after the other in function of the fiber orientation and the applied strain mode. Hence, the model is called “first pseudo-grain failure model” by analogy with the “first ply failure model” in laminated composites. An evaluation of the proposed model against experimental data is conducted for short-glass-fiber reinforced polyamide 6,6 (PA6,6). It is shown that the model yields satisfactory predictions of the response under uniaxial tension of composite samples with different fiber contents cut under various directions relative to the main injection flow direction.  相似文献   
29.
A simplex-centroid experimental design was used for the optimization of both reducing and oxidizing improvers, namely Aspergillus oryzae S2 α-amylase (Amy), ascorbic acid (Asc), and glucose oxidase (GOD). This optimization was performed to enhance the dough and breadmaking qualities of soft French wheat flour and a composite counterpart that contained 30% Ukrainian wheat flour. Statistically significant correlations were calculated between the W index and textural parameters (e.g., dough chewiness and bread cohesiveness). The findings revealed that while the best mixture for French flour comprised 21.8% of Amy, 41.2% of Asc, and 37% of GOD, for the composite counterpart, it comprised 2.3% of Amy, 66% of Asc, and 31.7% of GOD. These optimized mixtures rearranged soft French wheat flour and its composite counterpart to a good quality and an improved flour texture, respectively. Additionally, they increased the loaf specific volumes of the breads made from soft French wheat flour and its counterpart by 25.8 and 45.43%, respectively, significantly decreased the breads’ susceptibility to microbial contamination, and reclassified the breads as “good” in terms of sensory attributes.  相似文献   
30.
Topology optimization of foundation structures is conducted using a direct limit analysis based optimization approach. Originally developed for plastic topology design of 2D superstructures and industrial structures, which are traditionally designed based on elasticity, the direct limit analysis based design method demonstrated strong intrinsic properties that make of it a promising alternative for topology design. Unlike existing methods the one proposed here is fundamentally conceived and developed in the framework of direct plastic limit analysis which is the natural and usual known framework for the analysis and design of geotechnical structures. The method is extended to handle foundation design by providing for the simultaneous presence of two materials: the soil and the reinforcement, governed by Coulomb failure law. Two types of designs are considered, namely, continuous and discrete. The first allows a range of graded densities of reinforcement that may in practice represent the types of mixtures used in soil improvement, such as cementation. In the discrete design the reinforcement consists exclusively of solid structural elements. A series of two dimensional example problems demonstrate the capabilities of the method to generate rational classical designs or uncommon but intuitively sound foundation configurations that could inspire designers to develop novel solutions.  相似文献   
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