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In this paper, we are concerned with locating the most congested regions in FPGA designs before routing is completed. As well, we are interested in the amount of congestion in these locations relative to surrounding areas. If this estimation is done accurately and early enough, e.g. prior to routing or even prior to placement, the data can be used during clustering, placement and perhaps during routing to avoid or spread out congestion before it becomes a problem. We implemented several estimation methods in the VPR tool set and visually compare estimation results to an actual routing congestion map. We find that standard image processing techniques such as blending and peak saturation considerably improve the quality of estimation for all metrics.

Little is known about transport mechanisms in sloped dormant vegetated and compost only filters for roadway runoff. Residence time experiments were carried out in triplicate in 0.254 m wide × 0.65 m long by 0.10 m deep beds using a bromide tracer. Bed slope was 12°. Only at the lowest flow rate tested (0.276 l/min per m of filter width) were mean residence times in compost beds with and without dormant grasses different. Pools formed ahead of beds at higher flow rate, and pool depth reached bed depth at 3.54 l/min/m. The ideal model of a well-mixed pool in series with a plug flow porous bed was a good predictor of effluent concentration data at flows ≥2.66 l/min/m. Theoretical contact volume within the beds increased with flow rate to reach approx. 30% of available pore space, while free drainage volume declined. Data shows that designs for sloped compost filter beds must consider flow, bed depth and length, and whether or not areas for pooling are needed.

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