18802972
A diagnostic fault simulator for fast diagnosis of bridge faults
A new diagnostic fault simulator is described that diagnoses both feedback and non-feedback bridge faults while using information from fault simulation of single stuck-at faults. A realistic fault model is used which considers the existence of the Byzantine Generals Problem. The approach has been demonstrated for two-line bridge faults on several large combinational benchmark circuits and has achieved over 98% accuracy for non-feedback bridge faults and over 80% accuracy for feedback bridge faults with good diagnostic resolution.
2622485
Diagnostic test generation for sequential circuits
Efficient diagnosis of faults in VLSI circuits requires high quality diagnostic test sets. In this work novel techniques for diagnostic test generation are proposed that require significantly less time than previous methods. The set of fault pairs left undistinguished by a detection-oriented test set is first filtered to target only testable faults. Then diagnostic test generation is performed using a genetic algorithm (GA) combined with a diagnostic fault simulator. A new fitness metric is proposed for the GA that accurately measures the quality of candidate sequences while requiring a limited amount of CPU time. Experimental results illustrate the effectiveness of the approach for sequential circuits.
6832021
Multiresolution Image Registration Based on Kullback-Leibler Distance
This paper extends our prior work on multi-modal image registration based on the a priori knowledge of the joint intensity dis- tribution that we expect to obtain, and Kullback-Leibler distance. This expected joint distribution can be estimated from pre-aligned training images. Experimental results show that, as compared with the Mutual Information and Approximate Maximum Likelihood based registration methods, the new method has longer capture range at different image resolutions, which can lead to a more robust image registration method. Moreover, with a simple interpolation algorithm based on non-grid point random sampling, the proposed method can avoid interpolation artifacts at the low resolution registration. Finally, it is experimentally demon- strated that our method is applicable to a variety of imaging modalities.
9991011
On sorting an intransitive total ordered set using semi-heap
The problem of sorting an intransitive total ordered set, a generalization of regular sorting, is considered. This generalized sorting is based on the fact that there exists a special linear ordering for any intransitive total ordered set. A new data structure called semi-heap is proposed to construct an optimal /spl Theta/(n log n) sorting algorithm. Finally, we propose a cost-optimal parallel algorithm using semi-heap. The run time of this algorithm is /spl Theta/(n) with /spl Theta/(log n) processors under the EREW PRAM model.
26599542
A Limited-Global Fault Information Model for Dynamic Routing in n-D Meshes
Summary form only given. A fault-tolerant routing in nD meshes with dynamic faults is provided. It is based on an early work on fault-tolerant routing in dynamic 2D meshes and 3D meshes where faults occur during a routing process. Unlike many traditional models that assume all the nodes know global fault information, our approach is based on the concept of limited global fault information. First, a fault model called faulty block is used in which all faulty nodes in the system are contained in a set of disjoint faulty blocks. Then, the information of faulty block needs to be distributed to a limited number of nodes at the boundaries of faulty block to avoid a message entering a detour area. When new faults occur, faulty blocks need to be reconstructed and their fault information needs to be redistributed. In this case, the update of fault information and the routing process proceed hand-in-hand. During the converging period, the routing process may experience more detours with inconsistent information. We study the limited distribution of fault information in nD meshes with dynamic faults. Our study shows that fault information can be distributed quickly to help the routing process. Therefore, the performance of routing process degrades gracefully in such a dynamic system.
874580
A limited-global fault information model for dynamic routing in n-D meshes
Summary form only given. A fault-tolerant routing in nD meshes with dynamic faults is provided. It is based on an early work on fault-tolerant routing in dynamic 2D meshes and 3D meshes where faults occur during a routing process. Unlike many traditional models that assume all the nodes know global fault information, our approach is based on the concept of limited global fault information. First, a fault model called faulty block is used in which all faulty nodes in the system are contained in a set of disjoint faulty blocks. Then, the information of faulty block needs to be distributed to a limited number of nodes at the boundaries of faulty block to avoid a message entering a detour area. When new faults occur, faulty blocks need to be reconstructed and their fault information needs to be redistributed. In this case, the update of fault information and the routing process proceed hand-in-hand. During the converging period, the routing process may experience more detours with inconsistent information. We study the limited distribution of fault information in nD meshes with dynamic faults. Our study shows that fault information can be distributed quickly to help the routing process. Therefore, the performance of routing process degrades gracefully in such a dynamic system.
10351800
Identification of functional links between genes using phylogenetic profiles
MOTIVATION
Genes with identical patterns of occurrence across the phyla tend to function together in the same protein complexes or participate in the same biochemical pathway. However, the requirement that the profiles be identical (i) severely restricts the number of functional links that can be established by such phylogenetic profiling; (ii) limits detection to very strong functional links, failing to capture relations between genes that are not in the same pathway, but nevertheless subserve a common function and (iii) misses relations between analogous genes. Here we present and apply a method for relaxing the restriction, based on the probability that a given arbitrary degree of similarity between two profiles would occur by chance, with no biological pressure. Function is then inferred at any desired level of confidence.


RESULTS
We derive an expression for the probability distribution of a given number of chance co-occurrences of a pair of non-homologous orthologs across a set of genomes. The method is applied to 2905 clusters of orthologous genes (COGs) from 44 fully sequenced microbial genomes representing all three domains of life. Among the results are the following. (1) Of the 51 000 annotated intrapathway gene pairs, 8935 are linked at a level of significance of 0.01. This is over 30-fold greater than the 271 intrapathway pairs obtained at the same confidence level when identical profiles are used. (2) Of the 540 000 interpathway genes pairs, some 65 000 are linked at the 0.01 level of significance, some 12 standard deviations beyond the number expected by chance at this confidence level. We speculate that many of these links involve nearest-neighbor path, and discuss some examples. (3) The difference in the percentage of linked interpathway and intrapathway genes is highly significant, consistent with the intuitive expectation that genes in the same pathway are generally under greater selective pressure than those that are not. (4) The method appears to recover well metabolic networks. This is illustrated by the TCA cycle which is recovered as a highly connected, weighted edge network of 30 of its 31 COGs. (5) The fraction of pairs having a common pathway is a symmetric function of the Hamming distance between their profiles. This finding, that the functional correlation between profiles with near maximum Hamming distance is as large as between profiles with near zero Hamming distance, and as statistically significant, is plausibly explained if the former group represents analogous genes.
7054272
Virtual Backbone Construction in MANETs Using Adjustable Transmission Ranges
Recently, the use of a virtual backbone in various applications in mobile ad hoc networks (MANETs) has become popular. These applications include topology management, point and area coverage, and routing protocol design. In a MANET, one challenging issue is to construct a virtual backbone in a distributed and localized way while balancing several conflicting objectives: small approximation ratio, fast convergence, and low computation cost. Many existing distributed and localized algorithms select a virtual backbone without resorting to global or geographical information. However, these algorithms incur a high computation cost in a dense network. In this paper, we propose a distributed solution based on reducing the density of the network using two mechanisms: clustering and adjustable transmission range. By using adjustable transmission range, we also achieve another objective, energy-efficient design, as a by-product. As an application, we show an efficient broadcast scheme where nodes (and only nodes) in a virtual backbone are used to forward the broadcast message. The virtual backbone is constructed using Wu and Li's marking process (1999) and the proposed density reduction process. The application of the density reduction process to other localized algorithms is also discussed. The efficiency of our approach is confirmed through both analytical and simulation study