Kunihiro Fujiyoshi

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The earliest and the most critical stage in VLSI layout design is the placement. The background of which is the rectangle packing problem: Given set of rectangular modules of arbitrary sizes, place them without overlap on a plane within a rectangle of minimum area. Since the variety of the packing is uncountably infinite, the key issue for successful(More)
A new method of packing the 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(More)
The first and the most critical stage in VLSI layout design is the placement, the background of which is the rectangle packing problem: Given many rectangular modules of arbitrary size, place them without overlapping on a layer in the smallest bounding rectangle. Since the variety of the packing is infinite (two- dimensionally continuous) many, the key(More)
A new method of packing the rectangles is proposed with applications to integarted circuit (IC) layout design. A special work-sheet, called the bounded-sliceline grid, is introduced. It consists of special segments that dissect the plane into rooms to which binary relations “right-of”and “above” are associated such that any two rooms are uniquely in either(More)
The sequence-pair was proposed in 1994 as a representation of the packing of rectangles of general structure. Since then, there have been efforts to expand its applicability over simple rectangles. This paper proposes a new way to represent the packing of a set of rectilinear blocks, including arbitrary concave rectilinear blocks. Our idea is in(More)
In recent high-performance analog integrated circuit design, it is often required to place some cells symmetrically to a horizontal or vertical axis. Balasa et al. proposed a method of obtaining the closest placement that satisfies the given symmetry constraints and the topology constraints imposed by a sequence-pair (seq-pair). However, this method has the(More)
In a typical VLSI/PCB design, some modules are pre-placed in advance, and the other modules are requested to be placed without overlap with these pre-placed modules. The presence of such obstacles introduces inconsistency to a coding scheme, called sequence-pair, which has been proposed for an obstacle free placement problem. We solve this di culty by(More)
In this paper, we propose "selected sequence-pair" (SSP), a sequence-pair (seq-pair) with the limited number of subsequences called adjacent crosses. Its features are: (1) The smallest packing based on a given SSP can be obtained in <i>O(n)</i> time, where <i>n</i> is the number of rectangles. (2) An arbitrary packing can be represented by SSP. (3) The(More)
Recently, it is often required in high performance analog IC design that some cells are placed symmetrically to horizontal or vertical axis. Balasa et al. proposed a method of obtaining the closest placement satisfying the given symmetry constraints and the topology constraints imposed by a sequence-pair, but this method has the following defects: (1) Some(More)