44324303
Equivalent permutation capabilities between time division optical omega network and non-optical extra stage omega network
Since optical networks must support crosstalk-free (CF) connections, regular N/spl times/N multistage interconnection networks (MINs) cannot be directly used to provide connections between N inputs and N outputs. A solution is to use a 2N/spl times/2N Cube-Type MIN to provide the N/spl times/N connections. C. Qiao (1993) proposed a time domain approach that divides the N optical inputs into several groups such that CF connections can be provided by an N/spl times/N regular MIN in several time slots, one for each group. The set of N-permutations realizable in two slots is defined as class /spl theta/. Qiao proved that the size of /spl theta/ is larger than the size of class /spl Omega/, where /spl Omega/ consists of all N-permutations passible through a regular N/spl times/N Omega network. The paper first presents an optimal O(NlgN) time algorithm for identifying whether a given permutation belongs to class /spl theta/ or not. From this algorithm, the paper proves an interesting fact that the class /spl theta/ is identical to the class /spl Omega/+1 which represents the set of N-permutations admissible by a non-optical N/spl times/N one-extra stage Omega network.
7243220
Finding multiple routing paths in wide-area WDM networks
In this paper the multiple routing path problem in wide area Wavelength Division Multiplexing (WDM) networks is considered, which is to find K edge-disjoint lightpaths/semi-lightpaths from a source to a destination such that the K paths meet some specified optimization objectives if they exist. Two versions of the problem are studied One is to minimize the total cost of the K paths. Another is to minimize the cost of the maximum cost path among the K paths. An efficient algorithm for the first version is proposed, which takes O (kK (kn + m + n log(kn))) time and delivers an exact solution, where n, m, and k are the number of nodes, links and wavelengths in the network. The second version of the problem is shown to be NP-hard, and an approximate algorithm for it is devised, delivering an approximate solution that is K times the optimum, where K /spl ges/ 2.
8438496
Permutation Routing in All-Optical Product Networks
In this paper we study permutation routing techniques for all-optical networks. Firstly, we show some lower bounds on the number of wavelengths needed for implementing any permutation on an all-optical network in terms of bisection of the network. Secondly, we study permutation routing on product networks by giving a lower bound on the number of wavelengths needed, and presenting permutation routing algorithms for the wavelength non-conversion and conversion models, respectively. Finally, we investigate permutation routing on a cube-connected-cycles network by showing that the number of wavelengths needed for implementing any permutation in one round is [2 log n], which improves on a previously known general result for bounded degree graphs by a factor of O(log 3 n) for this special case.
45976743
Improved lightpath (wavelength) routing in large WDM networks
We address the problem of efficient circuit switching in wide area networks. The solution provided is based on finding optimal routes for lightpaths and semilightpaths. A lightpath is a fully optical transmission path, while a semilightpath is a transmission path constructed by chaining several lightpaths together, using wavelength conversion at their junctions. The problem thus is to find an optimal lightpath/semilightpath in the network in terms of the cost of wavelength conversion and the cost of using the wavelengths on links. We first present fast, efficient algorithms both for the general problem and for a natural restricted version. The new algorithms outperform earlier work, providing time improvements amounting to an almost linear time factor in most cases. Also, all our algorithms can be implemented on the network in a distributed way.
31888135
An automatic seal imprint verification approach
The automatic verification of seal imprints is a difficult pattern recognition problem and has a lot of applications in the oriental countries. Several approaches have been proposed in the past 10 years, but all of them were hard to implement in practice because of their drawbacks in the adaptability, reliability and practicality. In this paper, a new automatic seal imprint verification approach is presented. Due to the efficient and accurate registration method, a set of effective features and the elaborate implementations, this approach has satisfied most practical requirements and has been used for a practical check verification system in a Chinese bank.
34776029
Embedding between 2-D meshes of the same size
It is shown how to embed an x/sub 1/ /spl times/ 1/sub 1/ mesh M/sub 1/ into an s/sub 2/ /spl times/ t/sub 2/ mesh M/sub 2/, where s/sub 1/ /spl times/ t/sub 2/, s/sub 1/ < t/sub i/ (i = 1,2) such that the dilation is minimized. It is assumed that load = 1 and expansion = 1. For each case there is shown a lower bound on the dilation and a corresponding embedding method. The dilations by these embedding algorithms either match a lower bound or are very close to a lower bound.<<ETX>>
10424667
Miss Rate Prediction Across Program Inputs and Cache Configurations
Improving cache performance requires understanding cache behavior. However, measuring cache performance for one or two data input sets provides little insight into how cache behavior varies across all data input sets and all cache configurations. This paper uses locality analysis to generate a parameterized model of program cache behavior. Given a cache size and associativity, this model predicts the miss rate for arbitrary data input set sizes. This model also identifies critical data input sizes where cache behavior exhibits marked changes. Experiments show this technique is within 2 percent of the hit rate for set associative caches on a set of floating-point and integer programs using array and pointer-based data structures. Building on the new model, this paper presents an interactive visualization tool that uses a three-dimensional plot to show miss rate changes across program data sizes and cache sizes and its use in evaluating compiler transformations. Other uses of this visualization tool include assisting machine and benchmark-set design. The tool can be accessed on the Web at http://www.cs.rochester.edu/research/locality
9894542
Reliability optimization of distributed access networks with constrained total cost
In this paper, we study the system reliability optimization of distributed access networks subject to a constraint on the total cost. We first formulate the cost-constrained system reliability optimization problem as a searching process in a combinatorial tree, which enumerates all the possible solutions to the problem. Because the calculation of each possible solution for the reliability problem is extremely time-consuming, a novel algorithm, the Shrinking & Searching Algorithm (SSA), is proposed to speed up the searching process. SSA jointly considers the upper bound of the system reliability for each branch in the combinatorial tree, and the cost constraint on the possible solutions. It avoids most of the redundant calculations in the searching process by gradually shrinking the difference between lower & upper bounds of the length of a path in the corresponding combinatorial tree, which represents a feasible solution. Case study & simulation results are presented to demonstrate the performance of the SSA.
10284885
ACES: a contextual engine for search
In web information retrieval, users often have to modify their queries several times before they can reach a page that meets their information need. During these interactions with the search engine, the user provides a lot of useful information to the search engine, which can be exploited to infer the user information need. For instance, if a user types “lemur” as the query, most of the pages returned by the search engine are about the animal lemur or lemur information retrieval toolkit. On the other hand, if the search engine incorporates the previous query submitted by the same user, say, “information retrieval”, the search engine can disambiguate the meaning of “lemur” and present pages that are related to lemur information retrieval toolkit. We design and implement a sessionbased search engine ACES(A Contextual Engine for Search), which puts the search in context[2]. Although there have been several attempts at building a personalized or contextual search engine [3] or session based search engines [1], our search engine has the following new features, which will be demonstrated:
9685849
Adaptive data partition for sorting using probability distribution
Many computing problems benefit from dynamic partition of data into smaller chunks with better parallelism and locality. However, it is difficult to partition all types of inputs with the same high efficiency. This paper presents a new partition method in sorting scenario based on probability distribution, an idea first studied by Janus and Lamagna in early 1980's on a mainframe computer. The new technique makes three improvements. The first is a rigorous sampling technique that ensures accurate estimate of the probability distribution. The second is an efficient implementation on modern, cache-based machines. The last is the use of probability distribution in parallel sorting. Experiments show 10-30% improvement in partition balance and 20-70% reduction in partition overhead, compared to two commonly used techniques. The new method reduces the parallel sorting time by 33-50% and outperforms the previous fastest sequential sorting technique by up to 30%.
41177176
Call admission control for heterogeneous services in wireless networks
A distributed call admission control (CAC) scheme for heterogeneous services is proposed. The scheme is based on a non-preemptive priority polling scheme and takes advantages of statistically multiplexing user mobility information. It is shown that the scheme can achieve both high resource utilization and low handoff dropping probability.