A normalized configuration of floorplans and ABLR-relations
ABSTRACT The single-sequence (SS) debuted very recently as the literally simplest code to represent the consistent ABLR-relations (above, below, left-of, right-of) between every pair of objects. It is evolutional in several senses in that it does not convey the labels of objects and that objects could be either physical modules or topological rooms of a T-junction floorplan. Rather it is considered an extremal abstraction of those BSG, SP, O-Tree, etc. algorithms (for packing) and Q-seq, CBL, HPG, etc. (for floorplanning). The paper reports a discovery of a particular relation between SS and the normalized configuration of the floorplan called the unit-diagonal diagram.
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Conference Proceeding: An O-tree representation of non-slicing floorplan and its applications[show abstract] [hide abstract]
ABSTRACT: We present an ordered tree, O-tree, structure to represent non-slicing floorplans. The O-tree uses only n(2+[Ig n]) bits for a floorplan of n rectangular blocks. We define an admissible placement as a compacted placement in both x and y direction. For each admissible placement, we can find an O-tree representation. We show that the number of possible O-tree combinations is O(n! 2<sup>2n-2</sup>/n<sup>1.5</sup>). This is very concise compared to a sequence pair representation which has O((n!)2) combinations. The approximate ratio of sequence pair and O-tree combinations is O(n<sup>2 </sup>(n/4e)<sup>n</sup>). The complexity of the O-tree is even smaller than a binary tree structure for slicing floorplan which has O(n! 2<sup>5n-3</sup>/n<sup>1.5</sup>) combinations. Given an O-tree, it takes only linear time to construct the placement and its constraint graph. We have developed a deterministic floorplanning algorithm utilizing the structure of O-tree. Empirical results on MCNC benchmarks show promising performance with average 16% improvement in wire length, and 1% less in dead space over previous CPU-intensive cluster refinement methodDesign Automation Conference, 1999. Proceedings. 36th; 02/1999
Conference Proceeding: Module placement on BSG-structure and IC layout applications[show abstract] [hide abstract]
ABSTRACT: A new method of packing rectangles (modules) is presented with applications to IC layout design. It is based on the bounded-sliceline grid (BSG) structure. The BSG dissects the plane into rooms associated with binary relations “right-to”and “above” such that any two rooms are uniquely in either relation. A packing is obtained through an assignment of modules on the BSG. Followed by physical realization BSG-PACK. A simulated annealing searches for a goon packing of all packings by changing the assignments. Experiments showed that hundreds of rectangles are easily packed in a small rectangle area (chip) with quite good quality in area efficiency. A wide adaptability is demonstrated specific to IC layout design. Remarkable examples are: the chip is not necessarily rectangle, L-shaped modules and modules which are allowed to partially overlap each other can be handledComputer-Aided Design, 1996. ICCAD-96. Digest of Technical Papers., 1996 IEEE/ACM International Conference on; 12/1996
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ABSTRACT: Rate-controlled Hg injection experiments, NMR core tests and core flooding experiments are carried out to study the low permeability cores from the Daqing and Changqing oilfields. The forming and affecting factors are studied to demonstrate why the pseudo threshold pressure gradient to flow should be overcome. Because of the boundary layer caused by interaction between solid and fluid and the micro throats of low permeability reservoirs, the pseudo threshold pressure should be overcome for fluid to flow in low permeability reservoirs. Few throats are involved in the flow and the seepage cross section area is also less at lower pressures. The throats number and the seepage cross section area increase with the increasing of flooding pressure. The pore structure and movable fluid saturation of low permeability reservoirs have remarkable influence on the pseudo threshold pressure to flow, the bigger the mainstream throats and the movable fluid saturation, the less the pseudo threshold pressure to flow. The pseudo threshold pressure gradient to flow is a characteristic parameter of nonlinear flow degree and seepage ability and it is a synthetic symbol of pore structure and movable fluid saturation.Petroleum Exploration and Development. 01/2009; 36(2):232-236.