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The performance of TCM on equalized multipath fading ISI channels with different equalization schemes is examined. Trellis codes that are effective for AWGN channels and flat fading channels with interleaving are evaluated for equalized multipath fading channels. For joint MLSE equalization and decoding the equivalent uncoded system outperforms all the trellis-coded systems that are examined. Trellis codes that are designed for flat fading channels with interleaving perform well if interleaving is used and an MLSE equalizer is used before deinterleaving. An effective interleaver-deinterleaver is identified that allows joint DDFSE equalization and decoding to be used without the need for equalization before decoding 相似文献
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Engineering with Computers - The study is investigated the capacity of new artificial intelligence (AI) methodologies for shear strength (Vs) computation of reinforced concrete (RC) beams. The... 相似文献
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Organic polymers were extracted from okra, aloe vera, and hibiscus leaves and used as drag‐reducing additives (DRAs) to enhance the laminar flow in custom‐made microchannels that simulate the human brain vessels. The experiment was conducted using an open‐loop microfluidic system. The flow enhancement performance was evaluated as the function of percentage of flow increment of mucilage additives at different concentrations. Okra mucilage showed greater flow enhancement performance at higher mucilage concentration while both aloe vera and hibiscus mucilage performed better at lower additive concentration. The findings prove the potential of these organic polymers as DRAs to enhance the blood flow. 相似文献
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Three competing schemes have been proposed for multimedia transport over broadband wireless channels: (a) traditional UDP
(Postel, The User Datagram Protocol, 1980 [1]), (b) semi-cross-layer UDP-Lite (The Lightweight User Datagram Protocol, 2004
[2]), and (c) cross-layer header estimation (Khayam et al., IEEE Transactions on Multimedia 9(2):377–385, 2007 [3]; Khayam
and Radha, IEEE Transactions on Wireless Communications 6(11):3946–3954, 2007 [4]). In all these schemes, corrupted and lost
packets are recovered using FEC at the application layer. In this paper, we analytically and experimentally compare the performances
of these broadband wireless multimedia schemes. First, we derive lower bounds on the excepted FEC redundancy required by ideal
cross-layer header estimation, UDP and UDP-Lite over an arbitrary-order Markov wireless channel. We show that under realistic
wireless channel conditions, the cross-layer header estimation scheme always requires lesser redundancy than UDP and UDP-Lite.
We then propose a practical minimum distance decoding (MDD) header estimation scheme, which is receiver-based, low complexity
and highly accurate. Trace-driven multimedia experiments over wireless LANs demonstrate that MDD header estimation requires
significantly lesser FEC redundancy and renders better video quality than existing schemes. 相似文献
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Syed Ali Khayam Shirish S. Karande Muhammad Usman Ilyas Hayder Radha 《Multimedia, IEEE Transactions on》2007,9(2):377-385
Wireless multimedia studies have revealed that forward error correction (FEC) on corrupted packets yields better bandwidth utilization and lower delay than retransmissions. To facilitate FEC-based recovery, corrupted packets should not be dropped so that maximum number of packets is relayed to a wireless receiver's FEC decoder. Previous studies proposed to mitigate wireless packet drops by a partial checksum that ignored payload errors. Such schemes require modifications to both transmitters and receivers, and incur packet-losses due to header errors. In this paper, we introduce a receiver-based scheme which uses the history of active multimedia sessions to detect transmitted values of corrupted packet headers, thereby improving wireless multimedia throughput. Header detection is posed as the decision-theoretic problem of multihypothesis detection of known parameters in noise. Performance of the proposed scheme is evaluated using trace-driven video simulations on an 802.11b local area network. We show that header detection with application layer FEC provides significant throughput and video quality improvements over the conventional UDP/IP/802.11 protocol stack 相似文献
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The second order differential equation of interface shear is formulated for fiber-reinforced polymer-strengthened beams using beam theory with a shear deformable adhesive layer. The solution of the boundary value problem is obtained in closed form and is used to derive deflection expressions for different loading conditions. The solution is also extended to analyze partially plated beams. The results converge to the extreme cases of very poorly and perfectly bonded plates and they help identify values of the adhesive shear modulus for effective stiffening. Furthermore, the solution of partially plated beams aids in defining anchorage lengths needed to develop the full or the highest possible composite action at midspan. 相似文献
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Mrityunjay Kumar David D. Conger Rodney L. Miller Jiebo Luo Hayder Radha 《Journal of Signal Processing Systems》2011,65(2):159-169
As displays become less expensive and are incorporated into more and more devices, there has been an increased focus on image
resizing techniques to fill an image to an arbitrary screen size. Traditional methods such as cropping or resampling can introduce undesirable losses in information or distortion in perception. Recently, content-aware image retargeting methods
have been proposed (Avidan and Shamir, ACM Trans Graphics 26(3), 2007; Guo et al., IEEE Trans Multimedia 11(5):856–867, 2009; Shamir and Avidan, Commun ACM 52(1), 2009; Simakov et al. 2008; Wolf et al. 2007), which produce exceptional results. In particular, seam carving, proposed by Avidan and Shamir, has gained attention as
an effective solution. However, there are many cases where it can fail. In this paper we propose a distortion-sensitive seam
carving algorithm for content-aware image resizing that improves edge preservation and decreases aliasing artifacts. In the
proposed approach, we use local gradient information along with a thresholding technique to guide the seam selection process
and provide a mechanism to halt seam carving when further processing would introduce unacceptable visual distortion in the
resized image. Furthermore, anti-aliasing filter is used to reduce the aliasing artifacts caused by seam removal. Experiments
have demonstrated superior performance over the current seam carving methods. 相似文献