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101.
Hybrid Model to Detect Zero Quantized DCT Coefficients in H.264 总被引:2,自引:0,他引:2
Hanli Wang Sam Kwong 《Multimedia, IEEE Transactions on》2007,9(4):728-735
In H.264 coding, there are a large number of discrete cosine transform (DCT) coefficients of the prediction residue which are quantized to zeros. Therefore, it is desired to design a method which can early detect zero quantized DCT coefficients (ZQDCT) before implementing DCT and quantization (Q) and thus reduce redundant computations for H.264 coding. To achieve this, a hybrid model is proposed in this paper in order to predict ZQDCT coefficients. First, the Gaussian distribution is applied to study the integer DCT coefficients in H.264 and hence an adaptive scheme with multiple thresholds is derived to realize different types of DCT and Q implementations. Then the adaptive scheme is further optimized by considering a more efficient condition to sufficiently detect all-zero DCT blocks. As a result, a hybrid model is developed. Compared with other methods in the literature, the proposed hybrid model is able to detect more ZQDCT coefficients and hence reduce more computations for H.264 encoding. It is shown by experimental results that the proposed hybrid model can achieve the best performance in reducing computations and obtain almost the same rate-distortion (R-D) performance as the original encoder in the H.264 reference software JM9.5 相似文献
102.
Xin Peng Wang Eu-Jin Lim A. Hong Yu Yu Ming-Fu Li Chi Ren Wei-Yip Loh Chun Xiang Zhu Chin A. Trigg A.D. Yee-Chia Yeo Biesemans S. Guo-Qiang Lo Dim-Lee Kwong 《Electron Devices, IEEE Transactions on》2007,54(11):2871-2877
A lanthanum (La)-doped HfN is investigated as an n-type metal gate electrode on SiO2 with tunable work function. The variation of La concentration in (HfinfinLa1-x)Ny modulates the gate work function from 4.6 to 3.9 eV and remains stable after high-temperature annealing (900degC to 1000degC), which makes it suitable for n-channel MOSFET application. An ultrathin high-fc dielectric layer was formed at the metal/SiO2 interface due to the (HfinfinLa1-x)Ny and SiO2 interaction during annealing. This causes a slight reduction in the effective oxide thickness and improves the tunneling current of the gate dielectric by two to three orders. We also report the tunability of TaN with Al doping, which is suitable for a p-type metal gate work function. Based on our results, several dual-gate integration processes by incorporating lanthanum or aluminum into a refractory metal nitride for CMOS technology are proposed. 相似文献
103.
Liu Ching-Ping C.-P. Yang Guu-Chang G.-C. Chiu Yu-Wen Y.-W. Kwong W.C. 《Wireless Communications, IEEE Transactions on》2007,6(6):2162-2171
In this paper, a multiple-rate, multicarrier direct- sequence code-division multiple-access (MC/DS-CDMA) system with the use of two-dimensional orthogonal variable spreading factor (2-D OVSF) codes is studied. They are the first 2-D codes that can be generated by the tree structure commonly used by one-dimensional OVSF codes in wideband-CDMA. The 2-D OVSF codes also preserve orthogonality among code matrices with different spreading factors in the code tree. The performances of the proposed system with RAKE receivers employing equal-gain and maximal-ratio combining methods are analyzed and compared. Our results show that our multiple-rate MC/DS-CDMA system with the 2-D OVSF codes is more suitable for a non-fading additive white Gaussian noise channel or a Rician weak-fading channel. However, in a Rayleigh fading channel, the system performance gets worse because the orthogonality of the 2-D OVSF codes is destroyed by the strong fading effect. 相似文献
104.
CD Spies J Herpell O Beck C Müller F Pragst S Borg A Helander 《Canadian Metallurgical Quarterly》1999,17(1):19-27
Interactions among growth factors are important in a variety of physiological and pathological processes. The regulation of IGF-I mRNA expression by bFGF was investigated in cultured rat Müller cells and the mechanism of regulation studied. Müller cells from 1- to 3-day-old Sprague-Dawley rats were isolated and cultured with Eagle MEM+10% FCS. Cultured cells were identified by immunocytochemistry using antibodies against vimentin, carbonic anhydrase C, and glutamine synthetase. Cells of passage 1-4 were treated with bFGF, the PKC inhibitor H-7, calphostin C, the PKC activator PMA or the PKA inhibitor H-89, as well as the adenylate cyclase activator forskolin, or adenylate cyclase inhibitor SQ22536. IGF-I and bFGF expression levels were assessed by Northern blot analysis. The addition of bFGF to culture medium down-regulated IGF-I expression in a dose- and time-dependent manner. Decrease of IGF-I expression started at a bFGF concentration of 1 ng ml-1. IGF-I mRNA level declined to 44% of baseline level at 10 ng ml-1 of bFGF, and reached a trough of 40% at 50 ng ml-1. At 10 ng ml-1 of bFGF, down-regulation of IGF-I expression was observed as early as 4 hr (60%) after treatment, and reached a trough of 42% by 8 hr. The temporal and concentration dependence of IGF-I expression by addition of the PKC activator PMA, to culture medium was similar to that due to the addition of bFGF. The down-regulation of IGF-I expression by bFGF (10 ng ml-1) and PMA (0.1 microM) was blocked by the PKC inhibitors H-7 (30 microM) and calphostin C (1 microM). Forskolin (5 microM), an adenylate cyclase activator, had activator, had no effect on IGF-I expression. SQ22536 (100 microM), an adenylate cyclase inhibitor, and H-89, a PKA inhibitor, had no inhibitory effect on bFGF-induced down-regulation of IGF-I expression. These results indicate that bFGF down-regulates IGF-I expression in cultured rat M uller cells through PKC activation. 相似文献
105.
Chandrakasan A. P. Daly D. C. Finchelstein D. F. Kwong J. Ramadass Y. K. Sinangil M. E. Sze V. Verma N. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2010,98(2):191-214
106.
The operation principles of a high-power high-efficiency GaAlAs superluminescent diode based on an internal absorber for lasing suppression is described. The absorber is based on an unpumped/reverse-biased section in the device, and the superluminescent diode characteristic depends heavily on the bias condition of the absorber section. The very high efficiency of the device arises from the strong waveguiding effect of the buried heterostructure. A theory which accurately describes the various device characteristics is described 相似文献
107.
Effects of dynamic stressing on nitrided and reoxidized-nitridedchemical-vapor-deposited gate oxides
Hwang H.-S. Ting W. Kwong D.-L. Lee J. Buhrow L. Bowling R.A. 《Electron Device Letters, IEEE》1989,10(12):568-570
The degradation behaviour of thin (110 Å) nitrided and reoxidized-nitrided chemical-vapor-deposited (CVD) SiO2 MOS gate dielectrics under dynamic voltage and current stressing is discussed. Results indicate that dynamic stressing increases charge-to-breakdown Q bd and reduces charge trapping and midgap interface state generation within the dielectrics. These improvements, which can be explained by charge detrapping under dynamic stressing, depend on process conditions and the stress duty cycle 相似文献
108.
109.
Jenny Folkesson Eigil Samset Raymond Y Kwong Carl-Fredrik Westin 《IEEE transactions on information technology in biomedicine》2008,12(3):328-334
This paper presents a segmentation method that extends geodesic active region methods by the incorporation of a statistical classifier trained using feature selection. The classifier provides class probability maps based on class representative local features, and the geodesic active region formulation enables the partitioning of the image according to the region information. We demonstrate automatic segmentation results of the myocardium in cardiac late gadolinium-enhanced magnetic resonance imaging (CE-MRI) data using coupled level set curve evolutions, in which the classifier is incorporated both from a region term and from a shape term from particle filtering. The results show potential for clinical studies of scar tissue in late CE-MRI data. 相似文献
110.
A guest–host approach was used to fabricate a one-layer organic light emitting diode (OLED). The thick film ink approach allows the two-dimensional OLED to be processed using traditional methods such as silk-screen printing. The I–V–L characteristics of the polymer thick film (PTF)-OLED were studied as a function of the device chemical compositions and physical configurations. Different polymers, hole and electron transporters, and emitters at different weight ratios were studied for its composition dependence. Device configuration also plays a significant role on its overall performance. Dependence on film thickness, electrode type, and the usage of additional charge injection layers were also investigated. The simplified one-layer device allows a straightforward interpretation for the charge-transport and recombination phenomena which shed light for its future improvement. 相似文献