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Full-Text Articles in Physical Sciences and Mathematics

Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen Dec 2006

Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen

Research Collection School Of Computing and Information Systems

We study the problem of finding a length-constrained maximum-density path in a tree with weight and length on each edge. This problem was proposed in [R.R. Lin, W.H. Kuo, K.M. Chao, Finding a length-constrained maximum-density path in a tree, Journal of Combinatorial Optimization 9 (2005) 147–156] and solved in O(nU) time when the edge lengths are positive integers, where n is the number of nodes in the tree and U is the length upper bound of the path. We present an algorithm that runs in O(nlog2n) time for the generalized case when the edge lengths are positive real numbers, which …


An Improved Distance Heuristic Function For Directed Software Model Checking, Eric G. Mercer, Neha Rungta Nov 2006

An Improved Distance Heuristic Function For Directed Software Model Checking, Eric G. Mercer, Neha Rungta

Faculty Publications

State exploration in directed software model checking is guided using a heuristic function to move states near errors to the front of the search queue. Distance heuristic functions rank states based on the number of transitions needed to move the current program state into an error location. Lack of calling context information causes the heuristic function to underestimate the true distance to the error; however, inlining functions at call sites in the control flow graph to capture calling context leads to an exponential growth in the computation. This paper presents a new algorithm that implicitly inlines functions at call sites …


Two Energy Efficient Algorithms For Tracking Objects In A Sensor Network, Arvind Rapaka, Sanjay Kumar Madria Jul 2006

Two Energy Efficient Algorithms For Tracking Objects In A Sensor Network, Arvind Rapaka, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

We propose two energy efficient algorithms for locating a target object moving in an area covered by a wireless ad hoc network. The first algorithm developed conserve energy by efficiently identifying sensor nodes, as Home Nodes, and use only local messages between neighboring nodes to follow the trail of the object. Since we avoid the long-range transmission and maximize the localization, the algorithms reduce the communication cost. The dynamic nature of the second algorithm exploits the predefined parameters such as the object velocity. Our algorithm represents query shipping against the conventional data shipping as a means to reduce the amount …


Hadamard Ideals And Hadamard Matrices With Two Circulant Cores, I. S. Kotsireas, C. Koukouvinos, Jennifer Seberry Jul 2006

Hadamard Ideals And Hadamard Matrices With Two Circulant Cores, I. S. Kotsireas, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We apply Computational Algebra methods to the construction of Hadamard matrices with two circulant cores, given by Fletcher, Gysin and Seberry. We introduce the concept of Hadamard ideal, to systematize the application of Computational Algebra methods for this construction. We use the Hadamard ideal formalism to perform exhaustive search constructions of Hadamard matrices with two circulant cores for the twelve orders 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. The total number of such Hadamard matrices is proportional to the square of the parameter. We use the Hadamard ideal formalism to compute the proportionality constants for …


Convergence Of Algorithms For Reconstructing Convex Bodies And Directional Measures, Richard J. Gardner, Markus Kiderlen, Peyman Milanfar Jun 2006

Convergence Of Algorithms For Reconstructing Convex Bodies And Directional Measures, Richard J. Gardner, Markus Kiderlen, Peyman Milanfar

Mathematics Faculty Publications

We investigate algorithms for reconstructing a convex body K in Rn from noisy measurements of its support function or its brightness function in k directions u1, . . . , uk. The key idea of these algorithms is to construct a convex polytope Pk whose support function (or brightness function) best approximates the given measurements in the directions u1, . . . , uk (in the least squares sense). The measurement errors are assumed to be stochastically independent and Gaussian. It is shown that this procedure is (strongly) consistent, meaning that, …


The Pseudosquares Prime Sieve, Jonathan P. Sorenson Jan 2006

The Pseudosquares Prime Sieve, Jonathan P. Sorenson

Scholarship and Professional Work - LAS

We present the pseudosquares prime sieve, which finds all primes up to n.


Fast Bounds On The Distribution Of Smooth Numbers, Scott T. Parsell, Jonathan P. Sorenson Jan 2006

Fast Bounds On The Distribution Of Smooth Numbers, Scott T. Parsell, Jonathan P. Sorenson

Scholarship and Professional Work - LAS

In this paper we present improvements to Bernstein’s algorithm, which finds rigorous upper and lower bounds for (x, y).


Generic Scheduling Framework And Algorithm For Time-Varying Wireless Networks, Gengfa Fang, Yi Sun, Jihua Zhou, Jinglin Shi, Eryk Dutkiewicz Jan 2006

Generic Scheduling Framework And Algorithm For Time-Varying Wireless Networks, Gengfa Fang, Yi Sun, Jihua Zhou, Jinglin Shi, Eryk Dutkiewicz

Faculty of Informatics - Papers (Archive)

In this paper, the problem of scheduling multiple users sharing a time varying wireless channel is studied, in networks such as in 3G CDMA and IEEE 802.16. We propose a new generic wireless packet scheduling framework (WPSF), which takes into account not only the quality of service (QoS) requirements but also the wireless resource consumed. The framework is generic in the sense that it can be used with different resource constraints and QoS requirements depending on the traffic flow types. Subsequently, based on this framework a minimum rate and channel aware (MRCA) scheduling algorithm is presented. MRCA attempts to greedily …


Sava: A Novel Self-Adaptive Vertical Handoff Algorithm For Heterogeous Wireless Networks, Min Liu, Zhong-Cheng Li, Xiao-Bing Guo, Eryk Dutkiewicz, Ming-Hui Wang Jan 2006

Sava: A Novel Self-Adaptive Vertical Handoff Algorithm For Heterogeous Wireless Networks, Min Liu, Zhong-Cheng Li, Xiao-Bing Guo, Eryk Dutkiewicz, Ming-Hui Wang

Faculty of Informatics - Papers (Archive)

The next generation wireless networking (4G) is envisioned as a convergence of different wireless access technologies with diverse levels of performance. Vertical handoff (VHO) is the basic requirement for convergence of different access technologies and has received tremendous attention from the academia and industry all over the world. During the VHO procedure, handoff decision is the most important step that affects the normal working of communication. In this paper, we propose a novel vertical handoff decision algorithm, self- adaptive VHO algorithm (SAVA), and compare its performance with conventional algorithms. SAVA synthetically considers the long term movement region and short term …