195349922
Routing for symmetric FPGAs and FPICs
195837988
An optimal algorithm for floorplan area optimization
An optimal algorithm for the VLSI floorplan area optimization problem is presented. The algorithm is an extension of the technique described by L. Stockmeyer (Information and Control, vol.59, p.91-101, 1983). Experimental results indicate that this algorithm pruned a very large number of redundant implementations. In addition, since the algorithm basically exploits the geometric property of the topology of the given floorplan it does not need to depend on the polar dual graphs to calculate the longest paths. Consequently it is able to run more efficiently than the branch-and-bound algorithm.<<ETX>>
2339232
Maze routing with OPC consideration
33246096
Optimal net assignment
We study in this paper the net assignment problem subject to the capacity constraint, selection constraint and routing constraint. Given two adjacent channels separated by a cell row, and a set of nets in each of the two channels, this problem is to assign to the cell row a subset of nets in each channel such that without violating any given constraint, the sum of the remaining densities of the two channels is minimized. The capacity constraint requires the density caused by the nets, which are assigned to the cell row, to be no more than a user-specified number k, where k is no more than the number of tracks available for routing over that cell row. The selection constraint specifies in each channel the subset of nets which are candidates to be assigned to the cell row. The routing constraint requires each net to be either completely assigned to the cell row or to stay in its channel. This problem can find its application in modeling a practical over-the-cell routing problem in which the whole region over the cell row is two-layer routable for the nets in the two adjacent channels. We present an optimal algorithm to solve this problem and provide experimental results to support our algorithm. >
47136995
Routing for symmetric FPGAs and FPICs
A new class of routing structures with fixed orthogonal wire segments and field programmable switches at the intersections of the wire segments is proposed. In comparison with the conventional two-dimensional field-programmable gate array (FPGA) routing structure, this class of routing structures has the advantage of using a smaller number of active programmable switches. An existing field-programmable interconnect chip (FPIC) routing structure can be included as a special case in our class of routing structures. Using a probabilistic model, we prove that complete routing can be achieved with a high degree of probability in a routing structure of this class in which the number of tracks in each channel approaches the lower bound asymptotically. We present a sequential routing algorithm based on the solution of the single net routing problem. We take into account the delay introduced by the active programmable switches on a routing path and formulate the single net routing problem as a node-weighted Steiner minimum tree (NWSMT) problem in a bipartite graph G. Since our single net routing problem is NP-complete, a polynomial time approximate algorithm is proposed. We prove that our single net routing algorithm produces an optimal solution for some special classes of bipartite graphs. In general, the solution obtained by our algorithm bas a performance bound of min{/spl Delta/(V/Z), |Z|-1}. Experimental results for several industrial circuits show a reduction of up to 41% in the number of active programmable switches when compared with corresponding results for the conventional FPGA routing structure.
9613111
Strategies for distributed search
The problem of locating information among cooperating agents within a distributed computing environment is considered. Such collections of agents can be collectively thought of as a single distributed application providing a single set of services; the X.500 distributed directory is an example of such an application. A central problem in such applications is the cooperative search for certain information which might be located at one of the agents. One approach to this problem relies on flooding messages throughout the distributed environment, such as that which might be used in routing algorithms to locate entries. Although the use of such algorithms, in principle, takes advantage of reaching many different agents via parallel data communication paths, the additional number of messages may be a distinct disadvantage in “higher layer” applications. This paper presents a variant of such approaches which rely on a depth-first method of distributing messages. Results of simulations illustrating the savings in messages of this approach to one relying on traditional flooding are presented for different network configurations.
41261093
Nano/micro technologies for single molecule manipulation and detection
A sensitive, rapid, and efficient single-molecule detection method was developed by combining fluorescence correlation spectroscopy (FCS) and on-chip molecular manipulation techniques. The highly restricted measurement volume in the FCS system significantly reduces the intrinsic background noise and facilitates single-molecule sensitivity. A microchannel integrated with multiple 3-D electrodes was fabricated and used for molecular sensing and manipulation by which individual DNA molecules were fast transported to and sequentially focused within the tiny probing volume for measuring single-molecular information, thereby enhancing both the efficiency and rates of detection.
6293093
Iterative Estimation of 3D Transformations for Object Alignment
An Iterative Estimation Algorithm (IEA) of 3D transformations between two objects is presented in this paper. Skeletons of the 3D objects are extracted using a fully parallel thinning technique, feature point pairs (land markers) are extracted from skeletons automatically with a heuristic rule, and a least squares method and an iterative approach are applied to estimate the 3D transformation matrix. The algorithm has three advantages. First of all, no initial transformation matrix is needed. Secondly, user interaction is not required for identifying the land markers. Thirdly, the time complexity of this algorithm is polynomial. Experiments show that this method works quite well with high accuracy when the translations and rotation angles are small, even when noise exists in the data.
16865574
On the superiority of DO-RE-ME/MPG-D over stuck-at-based defective part level prediction
Uses data collected from benchmark circuit simulations to examine the relationship between the tests which detect stuck-at faults and those which detect bridging surrogates. We show that the coefficient of correlation between these tests approaches zero as the stuck-at fault coverage approaches 100%. An enhanced version of the MPG-D model, which is based upon the number of detections of each site in a logic circuit, is shown to be superior to stuck-at fault coverage-based defective part level prediction. We then compare the accuracy of both predictors for an industrial circuit tested using two different test pattern sequences.
39372956
An Inequality on Connected Domination Parameters