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.
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>>
37059740
Realization of an Arbitrary Permutation on a Hypercube
We present an explicit combinatorial algorithm for constructing a 2-realization for any given permutation on a circuit-switched d-dimensional hypercube (d-cube) such that the total number of directed edges used in the realization (counting every repetition) is bounded by d2d, the total number of directed edges in the d-cube. As a corollary, this result implies a (2d−3) step realization on a packet-switched d-cube (d⩾3).
33412339
Conservative Algorithms for Parallel and Sequential Integer Sorting
We present a conservative CRCW parallel algorithm for integer sorting. This algorithm sorts n integers from {0, 1, ..., m−1} in time O(n log log min(m,n)/p + log n) using p processors. The simulation of our parallel algorithm on the sequential machine yields a sequential algorithm for integer sorting which sorts n integers from {0, 1, ..., m−1} in time O(n min(log log n, log log m/log n)).
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.
9442074
Generalized Latin squares II
Abstract This paper is a continuation of a study on a new class of combinatorial structures called generalized Latin squares or 〈k,l〉-Latin squares. Here, we study the existence question of perfect 〈k,l〉-Latin squares. The main result is an existence theorem for the case M = 2, where M is the multiplicity of the generalized Latin squares. Specifically, we show that for given positive integers N, k = ip, l = iq, where i = gcd(k,l), there exists a perfect 〈k,l〉-Latin square of order N with M = 2 if and only if (i) N = 4k, (ii) pq(p + q)| N, and (iii) q|2.
415324
Mobility information for resource management in wireless ATM networks
User mobility poses a significant technical challenge to network resource management in wireless ATM (Asynchronous Transfer Mode) networks. In order to guarantee quality of service (QoS) to mobile users and to achieve a high efficiency in network resource management, the information of mobile users' handoff at a future moment is essential for statistical multiplexing. This paper develops a novel fuzzy logic inference system to estimate the user mobility information for a wireless ATM network which uses a direct sequence code division multiple access (DS/CDMA) protocol. The estimation is based on measured pilot signal strengths from a number of the nearest base stations by the mobile user. Numerical results are presented to demonstrate the performance of the proposed technique under various path losses and channel shadowing conditions. The proposed technique can achieve simplicity, accuracy and low cost.
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%.
1789234
Phase-Based Miss Rate Prediction Across Program Inputs
Previous work shows the possibility of predicting the cache miss rate (CMR) for all inputs of a program. However, most optimization techniques need to know more than the miss rate of the whole program. Many of them benefit from knowing miss rate of each execution phase of a program for all inputs. 
 
In this paper, we describe a method that divides a program into phases that have a regular locality pattern. Using a regression model, it predicts the reuse signature and then the cache miss rate of each phase for all inputs. We compare the prediction with the actual measurement. The average prediction is over 98% accurate for a set of floating-point programs. The predicted CMR-traces matches the simulated ones in spite of dramatic fluctuations of the miss rate over time. This technique can be used for improving dynamic optimization, benchmarking, and compiler design.
14429022
Mining long-term search history to improve search accuracy
Long-term search history contains rich information about a user's search preferences, which can be used as search context to improve retrieval performance. In this paper, we study statistical language modeling based methods to mine contextual information from long-term search history and exploit it for a more accurate estimate of the query language model. Experiments on real web search data show that the algorithms are effective in improving search accuracy for both fresh and recurring queries. The best performance is achieved when using clickthrough data of past searches that are related to the current query.
6253791
Array regrouping and structure splitting using whole-program reference affinity
While the memory of most machines is organized as a hierarchy, program data are laid out in a uniform address space. This paper defines a model of reference affinity, which measures how close a group of data are accessed together in a reference trace. It proves that the model gives a hierarchical partition of program data. At the top is the set of all data with the weakest affinity. At the bottom is each data element with the strongest affinity. Based on the theoretical model, the paper presents k-distance analysis, a practical test for the hierarchical affinity of source-level data. When used for array regrouping and structure splitting, k-distance analysis consistently outperforms data organizations given by the programmer, compiler analysis, frequency profiling, statistical clustering, and all other methods we have tried.