In this paper we present a design of a switch wrapper as a component of SNA (SoC Network Architecture), which is an efficient on-chip-network compared to a shared bus architecture in a SoC. The SNA uses crossbar routers to provide the increasing demand on communication bandwidth within a single chip. A switch wrapper for SNA is located between a crossbar router and IPs connecting them together. It carries out a mode of routing to assist crossbar routers and executes protocol conversions to provide compatibility in IP reuse. A switch wrapper consists of a direct router, two AHB-SNP converters, a controller and two optional interface socket modules. We implemented a SNP switch wrapper in VHDL and confirmed its functionality using ModelDim simulation. Also, we synthesized it using a Xilinx Virtex2 device to determine resource requirements: the switch wrapper seems to occupy appropriate spaces, about 900 gates, considering that a single SNA crossbar router costs about 20,000 gates.

In this paper, we evaluate the performance of a new join algorithm, called hybrid join, which improves both the sort-merge and the hash-partitioned join algorithms. The hybrid join consists of completely sorting only the smaller relation and partitioning the other one into ranged buckets according to the order statistics of the sorted relation. The final joining is performed on the sorted relation and the ranged buckets. By analytical comparisons, we show that the hybrid join always outperforms the sort-merge join and guarantees better performance than that of the hash-partitioned join in practical situations. The analyses of the performances for the various methods are validated by simulation experiments.

In this paper, we present an error concealment method to recover damaged blocks for block-based image coding schemes. Imperfect transmission of image data results in damaged blocks in the reconstructed images. Hence recovering damaged image blocks is needed for reliable image communications. To recover damaged blocks is to estimate damaged blocks from the correctly received or undamaged neighborhood information with a priori knowledge about natural images. The recovery problem considered in our method is to estimate a larger block, which consists of a damaged block and the undamaged neighborhood, from the undamaged neighborhood. To find an accurate estimate, a set of the feature vectors is introduced and an estimate is expressed as a linear combination of the feature vectors. The proposed method recoveres damaged blocks by projecting the undamaged neighborhood information onto the feature vectors. The sequential projections onto the feature vectors algorithm is proposed to find the projection coefficients of the feature vectors to minimize the squared difference of an estimate and the undamaged neighborhood information. We tested our algorithm through computer simulations. The experimental results showed the proposed method ourperforms the frequency domain prediction method in the PSNR values by 4.0-5.0dB. Tthe reconstructed images by the proposed method provide a good subjective quality as well as an objective one.

A dual-hop amplify-and-forward (AF) relaying system with beamforming is analyzed over η-µ fading channels that includes Nakagami-m, Nakagami-q (Hoyt), and Rayleigh fading channels as special cases. New and exact expressions for the outage probability (OP) and average capacity are derived. Moreover, a new asymptotic analysis is also conducted for the OP and average capacity in terms of basic elementary functions which make it easy to understand the system behavior and the impact of channel parameters. The viability of the analysis is verified by Monte Carlo simulations.