Abstract — In this paper we propose a method for standard cell placement with support for dual supply voltages, aiming to reduce total power under timing constraints and to implement voltage islands with minimal overheads. The method begins with timing and power driven coarse placement, followed by a few iterations between voltage assignment and placement refinement to generate voltage islands. Several techniques, including timing and power driven net weighting, seed growth based voltage assignment, and soft clustering strategy for placement refinements are employed in our implementation. Experimental results on a set of MCNC benchmarks show that our approach is able to produce feasible placement for dual-Vdd designs and significantly reduce total power with a wirelength increase within 14 % compared to a power and timing driven placer without voltage islands. I.

Floorplanning algorithms have traditionally underperformed experienced designers, even when relatively simple interconnect metrics are concerned. However, the sheer scale of modern systems on chip makes an all-manual design flow infeasible. In this paper, we propose a new efficient automated approach to the floorplan repair problem, where a set of violated design constraints are satisfied by applying small changes to an existing rough floorplan. Such a floorplan can be produced by a human designer, by a scalable placement algorithm, or result from engineering adjustments to a pre-existing floorplan. In all cases, overlapping modules must be separated, and in some instances, modules may need to be repositioned to satisfy other requirements. The algorithmic framework we propose is built upon an expressive graph-based encoding of constraints. While capable of representing

Tag clouds provide an aggregate of tag-usage statistics. They are typically sent as in-line HTML to browsers. However, display mechanisms suited for ordinary text are not ideal for tags, because font sizes may vary widely on a line. As well, the typical layout does not account for relationships that may be known between tags. This paper presents models and algorithms to improve the display of tag clouds that consist of in-line HTML, as well as algorithms that use nested tables to achieve a more general 2-dimensional layout in which tag relationships are considered. The first algorithms leverage prior work in typesetting and rectangle packing, whereas the second group of algorithms leverage prior work in Electronic Design Automation. Experiments show our algorithms can be efficiently implemented and perform well.