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On the Approximability of Reachability-Preserving Network Orientations

Michael Elberfeld, Vineet Bafna, Iftah Gamzu, Alexander Medvedovsky, Danny Segev, Dana Silverbush, Uri Zwick, Roded Sharan
2011 Internet Mathematics  
We introduce a graph orientation problem arising in the study of biological networks. Given an undirected graph and a list of ordered source-target vertex pairs, the goal is to orient the graph such that a maximum number of pairs admit a directed source-to-target path. We study the complexity and approximability of this problem. We show that the problem is NP-hard even on star graphs and hard to approximate to within some constant factor. On the positive side, we provide an Ω(log log n/ log
more » ... actor approximation algorithm for the problem on n-vertex graphs. We further show that for any instance of the problem there exists an orientation of the input graph that satisfies a logarithmic fraction of all pairs and that this bound is tight up to a constant factor. Our techniques also lead to constant factor approximation algorithms for some restricted variants of the problem.
doi:10.1080/15427951.2011.604554 fatcat:msvkismcd5er7kxxlgrq4div7y

An Algorithm for Orienting Graphs Based on Cause-Effect Pairs and Its Applications to Orienting Protein Networks [chapter]

Alexander Medvedovsky, Vineet Bafna, Uri Zwick, Roded Sharan
Lecture Notes in Computer Science  
We consider a graph orientation problem arising in the study of biological networks. Given an undirected graph and a list of ordered source-target pairs, the goal is to orient the graph so that a maximum number of pairs will admit a directed path from the source to the target. We show that the problem is NP-hard and hard to approximate to within a constant ratio. We then study restrictions of the problem to various graph classes, and provide an O(log n) approximation algorithm for the general
more » ... se. We show that this algorithm achieves very tight approximation ratios in practice and is able to infer edge directions with high accuracy on both simulated and real network data.
doi:10.1007/978-3-540-87361-7_19 fatcat:vhlztajbcngldiyls7swfzwycy

Page 12 of American Ceramic Society Bulletin Vol. 86, Issue 1 [page]

2007 American Ceramic Society Bulletin  
Louis Section and the Refractory Ceramics Division of The American Ceramic Society Mike Riverside Refractories Inc.; Dave Larsen, Program cochairs: Alexander, Blasch Precision Ceramics; and James Hemrick  ...  Christopher Cincinnati, during the & Technology Science new members are: Prabeer Berndt, James Cook University, Australia; Alex Cozzi, Savannah River National Lab; Christopher DiAntonio, Sandia National Labs; Medvedovski  ... 

PROJETO, PARAMETRIA E TECNOLOGIA I

Adriane Borda Almeida da Silva, Eduardo Grala da Cunha
2021 Pixo  
A sessão de artigos e ensaios apresenta, inicialmente, quatro trabalhos de abordagens teóricas e reflexivas: PROJETO, PADRÕES E TECNOLOGIA: da linguagem de Alexander à programação e inteligência artificial  ...  de mobiliário para promover processos colaborativos em contextos de habitação de interesse social, é um estudo de autoria de Adriane Borda Almeida da Silva, Cristiane dos Santos Nunes e Nirce Saffer Medvedovski  ... 
doi:10.15210/pixo.v5i17.21083 fatcat:hdg6jno2hjen7g3olpcqdyqvrm

Acknowledgement to Reviewers of Materials in 2016

2017 Materials  
Medri, Valentina Medvedovski, Eugene Meerman, Hans Meingast, Christoph Meka, S.R.  ...  Mitchell, Sharon Mitraki, Anna Nebot, Enrique Oakey, John Obara, Tomoko Obata, Kotaro Obraztsov, Alexander Ochiai, Tsuyoshi O'connor, Kevin E.  ... 
doi:10.3390/ma10010062 fatcat:c2okl3lidrbk7bjnw3ocjtwfme

Page 155 of Annual Review of Physical Chemistry Vol. 9, Issue [page]

Annual Review of Physical Chemistry  
Soc., 226 (1957) Alexander, P., Radiation Research, 6, 653 (1957)  ...  ., Medvedovsky, V. I., Revina, A. A., and Bitiukov, V. D., Akad. Nauk S.S.S.R. 1st Coll. Radiation Chem., 10 (Moscow, Russia, April, 1957) Boyle, J. W., and Mahlman, H. A., Nuclear Sci.  ... 

Optimally Orienting Physical Networks [chapter]

Dana Silverbush, Michael Elberfeld, Roded Sharan
2011 Lecture Notes in Computer Science  
On the positive side, Medvedovsky et al. [13] provided an ILP-based algorithm, and showed that the problem is approximable to within a ratio of O(log n), where n is the number of vertices in the network  ...  Alexander und Rita Besser-Stiftung. R.S. was supported by a research grant from the Israel Science Foundation (grant no. 385/06).  ...  The only previous method for orienting large undirected graphs is the one from Medvedovsky et al. [13] .  ... 
doi:10.1007/978-3-642-20036-6_39 fatcat:occm7yjcenczrps2ddka7p452y

Optimally Orienting Physical Networks

Dana Silverbush, Michael Elberfeld, Roded Sharan
2011 Journal of Computational Biology  
On the positive side, Medvedovsky et al. [13] provided an ILP-based algorithm, and showed that the problem is approximable to within a ratio of O(log n), where n is the number of vertices in the network  ...  Alexander und Rita Besser-Stiftung. R.S. was supported by a research grant from the Israel Science Foundation (grant no. 385/06).  ...  The only previous method for orienting large undirected graphs is the one from Medvedovsky et al. [13] .  ... 
doi:10.1089/cmb.2011.0163 pmid:21999286 fatcat:ykdvlozy75ekrjfrenajryq764

Using OPMs to measure neural activity in standing, mobile participants

Robert A. Seymour, Nicholas Alexander, Stephanie Mellor, George C. O'Neill, Tim M. Tierney, Gareth R. Barnes, Eleanor A. Maguire
2021 NeuroImage  
While movement compensation algorithms (e.g. based on signal space separation, Medvedovsky et al., 2007 ) are available for head movements on the order of 0.5-6 cm during SQUID-MEG scanning, much larger  ... 
doi:10.1016/j.neuroimage.2021.118604 pmid:34555493 pmcid:PMC8591613 fatcat:6z4mhfahozcvzlkrq56sngqgyu

Getting Antitrust and History in Tune

Brian R. Cheffins
2022 Accounting, Economics, and Law ? A Convivium  
TIMES, Sept. 9, 2018, 1 (quoting a tweet by Konstantin Medvedovsky, an antitrust lawyer). 37 Joshua Wright & Aurelien Portuese, Antitrust Populism: Towards a Taxonomy, 25 STAN. J.L.  ...  State Bar Association Antitrust Section, January 24, 2022, https://www.justice.gov/opa/ speech/assistant-attorney-general-jonathan-kanter-antitrust-division-delivers-remarks-newyork. 19 David Dayen & Alexander  ... 
doi:10.1515/ael-2021-0084 fatcat:nxro7gjafzgbhagwv4drgsh4hm

An Invitation to Tensor-Triangular Geometry

Paul Balmer
2017 Notices of the American Mathematical Society  
For further reading, see Discrete Differential Geometry (2008, Alexander Bobenko ed.).  ...  Photo of Solomon Marcus ©Alexander Okhotin, used under the GFDL. Alexandra Bellow, Northwestern University Cristian S.  ... 
doi:10.1090/noti1594 fatcat:ciebsoei5faltj5zoyfg3ewlfi

Ritualidades de assistência de ficção televisiva em tempos de pandemia [chapter]

Sandra Depexe, Veneza V. Mayora Ronsini, Camila da Silva Marques, Lúcia Loner Coutinho, Luiza Betat Corrêa
2021 Criação e inovação na ficção televisiva brasileira em tempos de pandemia de Covid-19  
A série As Five: lançamento e repercussão As Five estreou em novembro de 2020 no Globoplay e conta com 10 episódios que mostram a vida das protagonistas Keyla (Gabriela Medvedovski), Ellen (Heslaine Vieira  ...  a visualização de objetos ou personagens a diversas distâncias da câmera, Bazin ( 2014 ) ilustra o seu raciocínio com um frame do filme de Welles (Figura 7): na cena do suicídio fracassado de Susan Alexander  ... 
doi:10.29327/552823.1-10 fatcat:ykf3gjusxbg5jar4mrascenrqu