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 Kouzou Ohara

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Average citations per article3.41
Citation Count157
Publication count46
Publication years1996-2016
Available for download4
Average downloads per article154.00
Downloads (cumulative)616
Downloads (12 Months)65
Downloads (6 Weeks)7
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46 results found Export Results: bibtexendnoteacmrefcsv

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1
August 2016 PRICAI'16: Proceedings of the 14th Pacific Rim International Conference on Trends in Artificial Intelligence
Publisher: Springer
Bibliometrics:
Citation Count: 0

We address the problem of efficiently detecting critical links in a large network. Critical links are such links that their deletion exerts substantial effects on the network performance. Here in this paper, we define the performance as being the average node reachability. This problem is computationally very expensive because the ...
Keywords: link deletion, critical links, node reachability, social networks

2
February 2016 Information Sciences: an International Journal: Volume 329 Issue C, February 2016
Publisher: Elsevier Science Inc.
Bibliometrics:
Citation Count: 4

We propose an efficient method to discover a new type of influential nodes in a social network, which we name "super-mediators", i.e., those nodes which, if removed, decrease information spread. It is formulated mathematically as a problem of difference maximization of the average influence degree with respect to removal of ...
Keywords: Information diffusion, Influence degree, Super-mediator, Reverse-influence degree

3
October 2015 BIG DATA '15: Proceedings of the 2015 IEEE International Conference on Big Data (Big Data)
Publisher: IEEE Computer Society
Bibliometrics:
Citation Count: 0

Acquiring a network of trust relations among users in social media sites, e.g., item-review sites, is important for analyzing users' behavior and efficiently finding reliable information on the Web. We address the problem of predicting trustlinks among users for an item-review site. Non-negative matrix factorization (NMF) methods have recently been ...

4 published by ACM
July 2015 GECCO '15: Proceedings of the 2015 Annual Conference on Genetic and Evolutionary Computation
Publisher: ACM
Bibliometrics:
Citation Count: 0
Downloads (6 Weeks): 0,   Downloads (12 Months): 20,   Downloads (Overall): 79

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Recent studies reveal that the covariance matrix adaptation evolution strategy (CMA-ES) updates the parameters based on the natural gradient. The rank-based weight is considered the result of the quantile-based transformation of the objective value and the parameters are adjusted in the direction of the natural gradient estimated by Monte-Carlo with ...
Keywords: importance sampling, information geometric optimization, covariance matrix adaptation evolution strategy, natural gradient

5
April 2015 Journal of Intelligent Information Systems: Volume 44 Issue 2, April 2015
Publisher: Kluwer Academic Publishers
Bibliometrics:
Citation Count: 1

We propose a method of detecting the period in which a burst of information diffusion took place from an observed diffusion sequence data over a social network and report the results obtained by applying it to the real Twitter data. We assume a generic information diffusion model in which time ...
Keywords: Information diffusion, Social networks, Burst detection, Change point detection

6 published by ACM
August 2013 ASONAM '13: Proceedings of the 2013 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining
Publisher: ACM
Bibliometrics:
Citation Count: 0
Downloads (6 Weeks): 2,   Downloads (12 Months): 10,   Downloads (Overall): 79

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We address a problem of detecting changes in information posted to social media taking both content and posting time distributions into account. To this end, we introduce a generative model consisting of two components, one for a content distribution and the other for a timing distribution, approximating the shape of ...

7 published by ACM
July 2013 ACM Transactions on Intelligent Systems and Technology (TIST) - Special Sections on Paraphrasing; Intelligent Systems for Socially Aware Computing; Social Computing, Behavioral-Cultural Modeling, and Prediction: Volume 4 Issue 3, June 2013
Publisher: ACM
Bibliometrics:
Citation Count: 1
Downloads (6 Weeks): 4,   Downloads (12 Months): 26,   Downloads (Overall): 342

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We addressed the problem of detecting the change in behavior of information diffusion over a social network which is caused by an unknown external situation change using a small amount of observation data in a retrospective setting. The unknown change is assumed effectively reflected in changes in the parameter values ...
Keywords: social networks, Change point detection, information diffusion, parameter learning

8
April 2013 SBP'13: Proceedings of the 6th international conference on Social Computing, Behavioral-Cultural Modeling and Prediction
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 1

We address a new type of influence maximization problem which we call "target selection problem". This is different from the traditionally thought influence maximization problem, which can be called "source selection problem", where the problem is to find a set of K nodes that together maximizes their influence over a ...
Keywords: information diffusion, target node selection, influence degree

9
September 2012 ECMLPKDD'12: Proceedings of the 2012th European Conference on Machine Learning and Knowledge Discovery in Databases - Volume Part II
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 0

Social networks play an important role for spreading information and forming opinions. A variety of voter models have been defined that help analyze how people make decisions based on their neighbors' decisions. In these studies, common practice has been to use the latest decisions in opinion formation process. However, people ...

10
September 2012 ECML PKDD'12: Proceedings of the 2012 European conference on Machine Learning and Knowledge Discovery in Databases - Volume Part II
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 1

Social networks play an important role for spreading information and forming opinions. A variety of voter models have been defined that help analyze how people make decisions based on their neighbors' decisions. In these studies, common practice has been to use the latest decisions in opinion formation process. However, people ...

11 published by ACM
April 2012 WWW '12 Companion: Proceedings of the 21st International Conference on World Wide Web
Publisher: ACM
Bibliometrics:
Citation Count: 0
Downloads (6 Weeks): 1,   Downloads (12 Months): 9,   Downloads (Overall): 116

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We address the problem of visualizing structure of undirected graphs that have a value associated with each node into a K-dimensional Euclidean space in such a way that 1) the length of the point vector in this space is equal to the value assigned to the node and 2) nodes ...
Keywords: graph embedding, visualization, information diffusion

12
April 2012 SBP'12: Proceedings of the 5th international conference on Social Computing, Behavioral-Cultural Modeling and Prediction
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 1

How the information diffuses over a large social network depends on both the model employed to simulate the diffusion and the network structure over which the information diffuses. We analyzed both theoretically and empirically how the two contrasting most fundamental diffusion models, Independent Cascade (IC) and Linear Threshold (LT) behave ...
Keywords: network structure, node degree distribution, information diffusion, influence degree

13
March 2012 Knowledge and Information Systems: Volume 30 Issue 3, March 2012
Publisher: Springer-Verlag New York, Inc.
Bibliometrics:
Citation Count: 7

We address the problem of discovering the influential nodes in a social network under the susceptible/infected/susceptible model that allows multiple activation of the same node, by defining two influence maximization problems: final-time and integral-time . We solve this problem by constructing a layered graph from the original network with each ...
Keywords: Burnout method, SIS model, Pruning method, Influence maximization

14
December 2011 AI'11: Proceedings of the 24th international conference on Advances in Artificial Intelligence
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 3

We address the problem of visualizing structure of bipartite graphs such as relations between pairs of objects and their multi-labeled categories. For this task, the existing spherical embedding method, as well as the other standard graph embedding methods, can be used. However, these existing methods either produce poor visualization results ...

15
December 2011 Intelligent Data Analysis: Volume 15 Issue 4, June 2011
Publisher: IOS Press
Bibliometrics:
Citation Count: 5

We address the problem of estimating the parameters, from observed data in a complex social network, for an information diffusion model that takes time-delay into account, based on the popular independent cascade (IC) model. For this purpose we formulate the likelihood to obtain the observed data which is a set ...
Keywords: Social network analysis, node ranking, influence degree prediction, information diffusion model with time-delay, parameter learning

16
October 2011 DS'11: Proceedings of the 14th international conference on Discovery science
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 4

We address the problem of detecting anti-majority opinionists using the value-weighted mixture voter (VwMV) model. This problem is motivated by the fact that some people have a tendency to disagree with any opinion expressed by the majority. We extend the value-weighted voter model to include this phenomenon with the anti-majoritarian ...

17
July 2011 Intelligent Data Analysis: Volume 15 Issue 4, July 2011
Publisher: IOS Press
Bibliometrics:
Citation Count: 0

We address the problem of estimating the parameters, from observed data in a complex social network, for an information diffusion model that takes time-delay into account, based on the popular independent cascade IC model. For this purpose we formulate the likelihood to obtain the observed data which is a set ...
Keywords: Node Ranking, Parameter Learning, Social Network Analysis, Influence Degree Prediction, Information Diffusion Model With Time-Delay

18
June 2011 ISMIS'11: Proceedings of the 19th international conference on Foundations of intelligent systems
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 16

Information diffusion over a social network is analyzed by modeling the successive interactions of neighboring nodes as probabilistic processes of state changes. We address the problem of estimating parameters (diffusion probability and time-delay parameter) of the probabilistic model as a function of the node attributes from the observed diffusion data ...

19
March 2011 SBP'11: Proceedings of the 4th international conference on Social computing, behavioral-cultural modeling and prediction
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 1

We address the problem of detecting the change in opinion share over a social network caused by an unknown external situation change under the value-weighted voter model with multiple opinions in a retrospective setting. The unknown change is treated as a change in the value of an opinion which is ...
Keywords: change point detection, opinion share, voter model

20
October 2010 DS'10: Proceedings of the 13th international conference on Discovery science
Publisher: Springer-Verlag
Bibliometrics:
Citation Count: 2

We address the problem of discovering a different kind of influential nodes, which we call "super-mediator", i.e. those nodes which play an important role to pass the information to other nodes, and propose a method for discovering super-mediators from information diffusion samples without using a network structure. We divide the ...



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