11,174 research outputs found

    6. PERFORMING ORGANIZATION CODE

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    This report has been prepared as the final deliverable for Phase II of a project for the California Department of Transportation to develop a combined quantitative and qualitative approach for planning for improved intermodal connectivity at California airports. The objectives of this phase were to further develop the Intermodal Airport Ground Access Planning Tool (IAPT) to improve its functionality, to estimate updated versions of mode choice models for use with the IAPT, to correct errors in the calculation of performance parameters by the IAPT, and to conduct a case study as a test of the IAPT. The objective of developing the IAPT is to provide a standard, transparent and scientific way for quantitative airport ground access project evaluation at the airport level. A user-friendly graphical interface makes it easy for a user to run the model in the following sequence of steps: (a) to define performance measures and the associated transportation service data variables for the different modes involved; (b) to select a

    A 2k2k-Vertex Kernel for Maximum Internal Spanning Tree

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    We consider the parameterized version of the maximum internal spanning tree problem, which, given an nn-vertex graph and a parameter kk, asks for a spanning tree with at least kk internal vertices. Fomin et al. [J. Comput. System Sci., 79:1-6] crafted a very ingenious reduction rule, and showed that a simple application of this rule is sufficient to yield a 3k3k-vertex kernel. Here we propose a novel way to use the same reduction rule, resulting in an improved 2k2k-vertex kernel. Our algorithm applies first a greedy procedure consisting of a sequence of local exchange operations, which ends with a local-optimal spanning tree, and then uses this special tree to find a reducible structure. As a corollary of our kernel, we obtain a deterministic algorithm for the problem running in time 4knO(1)4^k \cdot n^{O(1)}
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