Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"undirected graphs"”.
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Algorithms for connectivity problems in undirected graphs : maximum flow and minimun [kappa]-way cut.
We consider two connectivity problems on undirected graphs: maximum flow and minimum k-way cut. The maximum flow problem asks about the connectivity between two specified nodes. A traditional approach is to search for augmenting paths. We explore the possibility of restricting the set of edges in …
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Statistical models for social support networks: Application of exponential models to undirected graphs with dyadic dependencies
Research on the relationship between social support and general well-being often focuses on the personal support network, the group of individuals upon whom one calls for assistance in any given situation. With more sophisticated theories of social support, researchers no longer consider the mere …
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Vertex Connectivity of Graphs: Algorithms and Bounds
… problems concerning vertex connectivity of undirected graphs and presents new bounds and algorithms for these problems.
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Odd multiway cut in directed acyclic graphs
… parameterized by the size of the solution in undirected graphs. In this work, we focus on directed acyclic graphs (DAGs) and design a fixed-parameter algorithm. Our main contribution is a broadening of the shadow-removal framework to address parity problems in DAGs. We complement our FPT …
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Exact Byzantine consensus under local-broadcast channels
… that under this model consensus is possible on undirected graphs that have $2f+1$ nodes and are $2f$-connected. In contrast, it is well known that with point-to-point links, achieving consensus requires at least $3f+1$ nodes and $2f + 1$ connectivity. We show a tight result for the case of a …
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Molecular graph Self attention and graph convolution for drug discovery
… of drug development. We model molecules as undirected graphs and use graph convolutions and self-attention to predict molecular properties. With a series of ablation studies, we demonstrate the added value of several key components in our network. We analyze two standard datasets: BBBP, …
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From graphs to matrices, and back : new techniques for graph algorithms
… (1 + [epsilon])-approximately minimum s-t cut in undirected graphs that gives the fastest known algorithms for these tasks. These algorithms are the first ones to improve the long-standing bound of O(n3/2') running time on sparse graphs; -- Multicommodity Flow Problems. We set forth a new method …
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Faster generation of random spanning trees
… approximately uniformly random spanning trees in undirected graphs. We show how to sample from a distribution that is within a multiplicative (1+6) of uniform in expected time ... . This improves the sparse graph case of the best previously known worst-case bound of O(min{mn, n2. 376}), which has …
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Tournaments With Forbidden Substructures and the Erdos-Hajnal Conjecture
… of Erdos and Hajnal states that for every undirected graph H there exists ɛ(H)>0 such that every undirected graph on n vertices that does not contain H as an induced subgraph contains a clique or a stable set of size at least n^{ɛ(H)}. In 2001 Alon, Pach and Solymosi proved that the …
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Efficient algorithms for distributed learning, optimization and belief systems over networks
… distributed learning algorithms for time-varying undirected graphs, time-varying directed graphs and a new acceleration scheme for fixed undirected graphs. For each of the network structures, we present explicit dependencies for the worst case network topology. Furthermore, we extend these belief …
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Topological Operations for Genus Distributions and Embeddings of Graphs
… on a plane or sphere. Genus embedding of graphs is one of the most studied subjects in topological graph theory. A polynomial is used to represent a graph's embedding distribution on di erent surfaces which are classi ed by genus. We discuss orientable genus embeddings of connected …
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Identifying and Mitigating Security Risks in Multi-Level Systems-of-Systems Environments
… and security grades in a series of reports and undirected graphs. The framework’s evolutionary approach to mitigating risks and the robustness function which can determine the appropriateness of the SoS, revealed promising results, with the framework and principal techniques identifying SoS …
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Pseudo-determinism
… NC algorithm for finding matchings in bipartite graphs. As a corollary, we also show a pseudo-deterministic NC algorithm for constructing DFS trees in graphs. We then show a reproducible algorithm for problems in search-RL. That is, we show an algorithm for problems in search-RL such that the …
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Parameterized Relaxations for Circuits and Graphs
… important computational problems on circuits and graphs, and design fast algorithms for relaxed versions of these tasks, that highlight tractable instances of problems which are provably hard in general. On circuits, we tackle the Majority-SAT problem, a task related to counting solutions to …
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Local-access generators for basic random graph models
… the whole random graph. Our results focus on undirected graphs with independent edge probabilities, that is, each edge is chosen as an independent Bernoulli random variable. We provide a general implementation for generators in this model. Then, we use this construction to obtain the first …
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Network coding
… rate for instances defined on directed and undirected graphs. We present a network coding instance in an undirected graph in which the maximum achievable rate is strictly smaller than the sparsity of the graph.
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Layering principles for wireless networks
… multiple destinations. A classical result in undirected wireline networks is the near optimality of routing (flow) for multiple-unicast traffic: the min-cut upper bound is within a logarithmic factor of the number of sources of the max-flow. This establishes the approximate capacity of …
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Planar Graphs and their Duals on Cylinder Surfaces
In this thesis, we investigates plane drawings of undirected and directed graphs on cylinder surfaces. In the case of undirected graphs, the vertices are positioned on a line that is parallel to the cylinder’s axis and the edge curves must not intersect this line. We show that a plane drawing is …
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Low latency queries on big graph data
… these goals is impossible for extremely dense graphs. The central theme of this dissertation is to show that these goals can, in fact, be achieved by exploiting {\em graph sparsity}, a property almost always encountered in big graph data. This dissertation formally establishes a separation …
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Faster algorithms for convex and combinatorial optimization
… for solving the maximum flow problem on directed graphs with m edges and n vertices. This improves upon the previous fastest running time of achieved over 15 years ago by Goldberg and Rao. --Maximum Flow Problem: We obtain one of the first almost-linear time randomized algorithms for approximating …
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