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Resultados filtrados por Publicador: Universidade Cornell

Domination games played on line graphs of complete multipartite graphs

Tananyan, Hovhannes G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/05/2014 Português
Relevância na Pesquisa
47.002534%
The domination game on a graph $G$ (introduced by B. Bre\v{s}ar, S. Klav\v{z}ar, D.F. Rall \cite{BKR2010}) consists of two players, Dominator and Staller, who take turns choosing a vertex from $G$ such that whenever a vertex is chosen by either player, at least one additional vertex is dominated. Dominator wishes to dominate the graph in as few steps as possible, and Staller wishes to delay this process as much as possible. The game domination number $\gamma _{{\small g}}(G)$ is the number of vertices chosen when Dominator starts the game; when Staller starts, it is denoted by $\gamma _{{\small g}}^{\prime }(G).$ In this paper, the domination game on line graph $L\left( K_{\overline{m}}\right) $ of complete multipartite graph $K_{\overline{m}}$ $(\overline{m}\equiv (m_{1},...,m_{n})\in \mathbb{N} ^{n})$ is considered, the exact values for game domination numbers are obtained and optimal strategy for both players is described. Particularly, it is proved that for $m_{1}\leq m_{2}\leq ...\leq m_{n}$ both $\gamma _{{\small g}}\left( L\left( K_{\overline{m}}\right) \right) =\min \left\{ \left\lceil \frac{2}{3}\left\vert V\left( K_{\overline{m}}\right) \right\vert \right\rceil ,\right.$ $\left. 2\max \left\{ \left\lceil \frac{1}{2}\left( m_{1}+...+m_{n-1}\right) \right\rceil ...

Lower bounds for on-line graph colorings

Gutowski, Grzegorz; Kozik, Jakub; Micek, Piotr; Zhu, Xuding
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.204395%
We propose two strategies for Presenter in on-line graph coloring games. The first one constructs bipartite graphs and forces any on-line coloring algorithm to use $2\log_2 n - 10$ colors, where $n$ is the number of vertices in the constructed graph. This is best possible up to an additive constant. The second strategy constructs graphs that contain neither $C_3$ nor $C_5$ as a subgraph and forces $\Omega(\frac{n}{\log n}^\frac{1}{3})$ colors. The best known on-line coloring algorithm for these graphs uses $O(n^{\frac{1}{2}})$ colors.

On-Line Difference Maximization

Kao, Ming-Yang; Tate, Stephen R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.34445%
In this paper we examine problems motivated by on-line financial problems and stochastic games. In particular, we consider a sequence of entirely arbitrary distinct values arriving in random order, and must devise strategies for selecting low values followed by high values in such a way as to maximize the expected gain in rank from low values to high values. First, we consider a scenario in which only one low value and one high value may be selected. We give an optimal on-line algorithm for this scenario, and analyze it to show that, surprisingly, the expected gain is n-O(1), and so differs from the best possible off-line gain by only a constant additive term (which is, in fact, fairly small -- at most 15). In a second scenario, we allow multiple nonoverlapping low/high selections, where the total gain for our algorithm is the sum of the individual pair gains. We also give an optimal on-line algorithm for this problem, where the expected gain is n^2/8-\Theta(n\log n). An analysis shows that the optimal expected off-line gain is n^2/6+\Theta(1), so the performance of our on-line algorithm is within a factor of 3/4 of the best off-line strategy.

Combining Peer-to-Peer and Cloud Computing for Large Scale On-line Games

Carlini, Emanuele
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/10/2015 Português
Relevância na Pesquisa
67.325596%
This thesis investigates the combination of Peer-to-Peer (P2P) and Cloud Computing to support Massively Multiplayer On- line Games (MMOGs). MMOGs are large-scale distributed applications where a large number of users concurrently share a real-time virtual environment. Commercial MMOG infrastructures are sized to support peak loads, incurring in high economical cost. Cloud Computing represents an attractive solution, as it lifts MMOG operators from the burden of buying and maintaining hardware, while offering the illusion of infinite machines. However, it requires balancing the tradeoff between resource provisioning and operational costs. P2P- based solutions present several advantages, including the inherent scalability, self-repairing, and natural load distribution capabilities. They require additional mechanisms to suit the requirements of a MMOG, such as backup solutions to cope with peer unreliability and heterogeneity. We propose mechanisms that integrate P2P and Cloud Computing combining their advantages. Our techniques allow operators to select the ideal tradeoff between performance and economical costs. Using realistic workloads, we show that hybrid infrastructures can reduce the economical effort of the operator, while offering a level of service comparable with centralized architectures.

Strategy correlations and timing of adaptation in Minority Games

Galla, Tobias; Sherrington, David
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/03/2005 Português
Relevância na Pesquisa
47.794414%
We study the role of strategy correlations and timing of adaptation for the dynamics of Minority Games, both simulationally and analytically. Using the exact generating functional approach a la De Dominicis we compute the phase diagram and the behaviour of batch and on-line games with correlated strategies, complementing exisiting replica studies of their statics. It is shown that the timing of adaptation can be relevant; while conventional games with uncorrelated strategies are nearly insensitive to the choice of on-line versus batch learning, we find qualitative differences when anti-correlations are present in the strategy assignments. The available standard approximations for the volatility in terms of persistent order parameters in the stationary ergodic states become unreliable in batch games under such circumstances. We then comment on the role of oscillations and the relation to the breakdown of ergodicity. Finally, it is discussed how the generating functional formalism can be used to study mixed populations of so-called `producers' and `speculators' in the context of the batch minority games.; Comment: 15 pages, 13 figures, EPJ style