2442553
Adaptive spectrum-based variable bit truncation of discrete cosine transform (DCT) for energy-efficient wireless multimedia communication
This work presents a new adaptive scheme to reduce the computation energy of the discrete cosine transform (DCT) architecture for image/video coding. The scheme employs the noise masking effect of quantization and the spectral difference of the quantization factors. Spectrum-based variable bit truncation is used to allocate more energy for the computations that affect the low frequency DCT coefficients more. We propose a benchmark driven search mechanism based on energy and distortion weight to find the optimal truncation sets for different quality constraints and quantization tables. They are stored in a look-up table (LUT) for the on-line reconfiguration. Simulation results show that significant energy saving is achieved with negligible quality degradation.
12189368
A data discarding framework for reducing the energy consumption of Viterbi decoder in decoding broadcasted wireless multi-resolution JPEG2000 images
Resolution scalable compression and power efficient channel decoder design are the enabling techniques for multi-resolution wireless multimedia broadcasting. In this paper, we propose a data-discarding framework which controls the switching of the Viterbi decoder between active and sleep mode for decoding multi-resolution JPEG2000 images to significantly reduce the overall power consumption of the channel decoder. In particular, the Viterbi decoder is put into sleep mode to skip the decoding of the redundant higher resolution data according to the results of the source decoding. The proposed framework is independent of the underlying communication channel and the architecture of the Viterbi decoder. Hence, it can be applied on top of any existing low-power Viterbi decoders to further reduce the overall power consumption. Our results show that up to 75% power reduction is achieved when the source resolution, the target resolution, and the compression ratio are 1024/spl times/1024, 256/spl times/256, and 1 bit/pixel (bpp), respectively.
8081608
An analytic model for Ge/Si core/shell nanowire MOSFETs considering drift-diffusion and ballistic transport
In this paper an analytic model for Ge/Si core/shell nanowire MOSFETs (NWFETs) is developed. First, the electrostatic potential and charge model are derived out from classical device physics. Then the drift-diffusion drain current model is obtained and verified by comparisons with the numerical simulation. The ballistic current model is obtained with the approximately described quantummechanical effect through modifying the intrinsic carrier concentration under 2-dimensional confinement. With the proposed model, the performances of Ge/Si core/shell NWFETs are analyzed and significant characteristics are demonstrated in details. The analytic model in this paper provides a framework for further developing compact models of the NWFETs with Ge/Si core/shell heterostructure for circuit design and simulation.
6983597
A Comparative Study of Parallel Prefix Adders in FPGA Implementation of EAC
Several regular parallel trees have been proposed over the years to optimize logic depth, area, fan-out and in- terconnect count for logic circuits. In this paper, we propose a comparative study of different parallel prefix trees used in the design of a new end-around carry (EAC) adder targeting FPGA technology. This new adder is based on the fast 128-bit binary floating-point EAC adder which has been implemented in the IBM POWER6 microprocessor's fused multiply-add unit. The parallel prefix tree implemented on the IBM's EAC adder is a Kogge-Stone tree which has been chosen for its high performance and its low power consumption. Our comparative study highlights the main performance differences among fourteen different architecture configurations when targeting an FPGA EAC adder design. We focus on the area requirements and the critical path delay of these designs. Our experimental results show that there is one architecture configuration with the lower area requirement and the higher performance.
2597775
Re-cinematography: improving the camera dynamics of casual video
This paper presents an approach to post-processing casually captured videos to improve apparent camera movement. Re-cinematography transforms each frame of a video such that the video better follows cinematic conventions. The approach breaks videos into shorter segments. For segments of the source video where the camera is relatively static, re-cinematography uses image stabilization to make the result look locked-down. For segments with camera motions, camera paths are keyframed automatically and interpolated with matrix logarithms to give velocity-profiled movements that appear intentional and directed. The approach automatically balances the tradeoff between motion smoothness and distortion to the original imagery. Results from our prototype show improvements to poor quality home videos.
17905519
A Measurement and Modeling Study of P2P IPTV Applications
P2P IPTV applications start to be very popular on the Internet. Previous work on measuring and analyzing P2P IPTV traffic mostly focuses on a specific type of P2P applications or the behavior characteristics of P2P IPTV nodes acting as a client. In this paper, we have undertaken an in-depth measurement and modeling study of the most common P2P IPTV applications, specially focusing on the behavior characteristics of peers acting as a server. We measure and model the distributions of flow inter-arrival time, arrival rate, duration and size. Our results show the following. The statistics can fit equally well into distributions. Due to the different strategies, there exhibit some differences in the traffic characteristics. But, because of P2P IPTV users behaving similarly, they mainly have similar distributions and the traffic of them all have heavy-tailed phenomenon. Insights obtained in this study will be valuable for the identification of P2P IPTV traffic.
42839671
A Novel Integrated Supporting System for Mesh-Pull Based P2P IPTV
This paper presents a novel integrated supporting system for the mesh-pull based P2P IPTV. The proposed system can monitor the service quality of each overlays within the system by initiating random walks to sample key metrics of the system periodically and analyze the service quality statistically, and improve them to some extend. When the service quality is below the threshold, the system will increase its upload bandwidth adaptive to the workload of the system. The supporting system will allocate its bandwidth among multiple overlays to get the as much revenue as possible. This paper presents the design of this architecture and describes its functions and shows its adaptability to the high dynamic nature of p2p IPTV system and fitness for commercial deployment. At last we verify the feasibility of the architecture by simulation, and the results show its performance and adaptability.