Papers by Bernardo Huberman
Multiagent and Grid …, 2005
Abstract. Distributed clusters like the Grid and PlanetLab enable the same statistical multiplexi... more Abstract. Distributed clusters like the Grid and PlanetLab enable the same statistical multiplexing efficiency gains for computing as the Internet provides for networking. One major challenge is allocating resources in an economically efficient and low-latency way. A common solution ...
Journal of Physics C Solid State Physics
The screened interaction V(r) between two opposite charges in the classical two-dimensional Coulo... more The screened interaction V(r) between two opposite charges in the classical two-dimensional Coulomb gas is discussed. This interaction appears in certain response functions of the one-dimensional fermion system, when the latter is mapped onto the two-dimensional Coulomb problem. The effect of the power-law behaviour of V(r) on these response functions, when the large momentum transfer coupling constant (g1) goes to zero from below and above the g1=0 line, is discussed.
We present a dynamical model of web site growth in order to explore the effects of competition am... more We present a dynamical model of web site growth in order to explore the effects of competition among web sites and to determine how they affect the nature of markets. We show that under general conditions, as the competition between sites increases, the model exhibits a sudden transition from a regime in which many sites thrive simultaneously, to a "winner take all market" in which a few sites grab almost all the users, while most other sites go nearly extinct. This prediction is in agreement with recent measurements on the nature of electronic markets. * SMM thanks the Fannie and John Hertz Foundation and the Stanford Graduate Fellowship for financial support. We thank Eytan Adar and Lada Adamic for stimulating discussions.
Revue économique, 1995
... Eve Caroli* Natalie Glance Bernardo Huberman ... Les competences acquises sont en effet propr... more ... Eve Caroli* Natalie Glance Bernardo Huberman ... Les competences acquises sont en effet propriet6 des salaries qui peuvent a tout moment quitter 1'entreprise si une firme concurrente, qui n'a pas supporte le cofit de leur forma-tion, leur propose une remuneration plus attractive ...
Group Decision and Negotiation, 2010
We present a dynamical model of cooperative efforts comprised of concurrently performed, interrel... more We present a dynamical model of cooperative efforts comprised of concurrently performed, interrelated tasks. The model contains a stochastic component to account for temporal fluctuations both in task performance and in the effect of a given unit of work on the project as a whole. We show that as the number of concurrent tasks increases, so does the average completion time. Also, for fixed system size, the dynamics of individual project realizations can exhibit large deviations from the average when fluctuations increase past a certain threshold, causing long delays in completion times. These effects are in agreement with empirical observation. We also show that the negative effects of both large groups and long delays caused by fluctuations may be mitigated by arranging projects in a hierarchical or modular structure. Our model is applicable to any arrangement of interdependent tasks, providing an analytical prediction for the average completion time as well as a numerical threshold for the fluctuation strength beyond which long delays are likely. In conjunction with previous modeling techniques, it thus provides managers with a predictive tool to be used in the design of a project's architecture.
Scientific American, 1994
... Social models explain how group cooperation arisesand why that behavior can suddenly change ... more ... Social models explain how group cooperation arisesand why that behavior can suddenly change by Natalie S. Glance and Bernardo A. Huberman ... worked in condensed matter physics, statistical mechanics and chaotic dynamics He is a co-recipient of the 1990 Prize of the ...
We present a dynamical theory of complex cooperative projects such as large engineering design or... more We present a dynamical theory of complex cooperative projects such as large engineering design or software development efforts, comprised of concurrent and interrelated tasks. The model accounts for temporal fluctuations both in task performance and in the interactions between related tasks. We show that as the system size increases, so does the average completion time. Also, for fixed system size,
A significant percentage of online content is now published and consumed via the mechanism of cro... more A significant percentage of online content is now published and consumed via the mechanism of crowdsourcing. While any user can contribute to these forums, a disproportionately large percentage of the content is submitted by very active and devoted users, whose continuing participation is key to the sites' success. As we show, people's propensity to keep participating increases the more they
The rise of the Internet has enabled collaboration and co- operation on an unprecedentedly large ... more The rise of the Internet has enabled collaboration and co- operation on an unprecedentedly large scale. The online en- cyclopedia Wikipedia, which presently comprises 7.2 mil- lion articles created by 7.04 million distinct editors, provides a consummate example. We examined all 50 million edits made to the 1.5 million English-language Wikipedia articles and found that the high-quality articles are distinguished
We describe a methodology for the automatic identification of communities of practice from email ... more We describe a methodology for the automatic identification of communities of practice from email logs within an organization. We use a betweeness centrality algorithm that can rapidly find communities within a graph representing information flows. We apply this algorithm to an email corpus of nearly one million messages collected over a two-month span, and show that the method is effective
Computing Research Repository, 2007
Since its inception six years ago, the online encyclopedia Wikipedia has accumu- lated 6.40 milli... more Since its inception six years ago, the online encyclopedia Wikipedia has accumu- lated 6.40 million articles and 250 million edits, contributed in a predominantly undirected and haphazard fashion by 5.77 million unvetted volunteers. Despite the apparent lack of order, the 50 million edits by 4.8 million contributors to the 1.5 million articles in the English-language Wikipedia follow strong certain overall
Proceedings of The National Academy of Sciences, 2002
We present an automated method of identifying communities of functionally related genes from the ... more We present an automated method of identifying communities of functionally related genes from the biomedical literature. These communities encapsulate human gene and protein interactions and identify groups of genes that are complementary in their function. We use graphs to represent the network of gene cooccurrences in articles mentioning particular keywords, and find that these graphs consist of one giant connected
Computing Research Repository, 2005
Abstract: We present an analysis of a person-to-person recommendationnetwork, consisting of 4 mil... more Abstract: We present an analysis of a person-to-person recommendationnetwork, consisting of 4 million people who made 16million recommendations on half a million products. We observedthe propagation of recommendations and the cascadesizes, which can be explained by a stochastic model. Wethen established how the recommendation network growsover time and how e#ective it is from the viewpoint of thesender and receiver of
Nature, 1999
We present a theory for the growth dynamics of the World Wide Web that takes into account the wid... more We present a theory for the growth dynamics of the World Wide Web that takes into account the wide range of stochastic growth rates in the number of pages per site, as well as the fact that new sites are created at different times. This leads to the prediction of a universal power law in the distribution of the number
Energy Engineering, 1994
In spite of the revolutionary advances in digital technology and operations research that have ta... more In spite of the revolutionary advances in digital technology and operations research that have taken place in the last decades, the state of the art in building environmental management does not often reflect those improvements. For instance, many modern buildings are still thermally controlled via pneumatic systems, while lighting in the offices is often under manual and inefficient control. Further,
International Conference on Multiagent Systems, 1995
A working solution to the problem of thermal resource distribution in a building is demonstrated ... more A working solution to the problem of thermal resource distribution in a building is demonstrated using a market-based systent In this system computational agents representing individual temperature controllers bid to buy or sell cool or warm air. They do so via a double-blind computerized auction which is moderated by a central computer auctioneer. The auctioneer sees to it that no
Proceedings of the 2007 international symposium on Wikis - WikiSym '07, 2007
The rise of the Internet has enabled collaboration and cooperation on an unprecedentedly large sc... more The rise of the Internet has enabled collaboration and cooperation on an unprecedentedly large scale. The online encyclopedia Wikipedia, which presently comprises 7.2 million articles created by 7.04 million distinct editors, provides a consummate example. We examined all 50 million edits made to the 1.5 million English-language Wikipedia articles and found that the high-quality articles are distinguished by a marked increase in number of edits, number of editors, and intensity of cooperative behavior, as compared to other articles of similar visibility and age. This is significant because in other domains, fruitful cooperation has proven to be difficult to sustain as the size of the collaboration increases. Furthermore, in spite of the vagaries of human behavior, we show that Wikipedia articles accrete edits according to a simple stochastic mechanism in which edits beget edits. Topics of high interest or relevance are thus naturally brought to the forefront of quality.
World Wide Web Conference Series, 1994
We present a detailed model of collaboration in communities of practice and we examine its dynami... more We present a detailed model of collaboration in communities of practice and we examine its dynamical consequences for the group as a whole. We establish the existence of a novel mechanism that allows the community to naturally adapt to growth, specialization, or changes in the environment without the need for central controls. This mechanism relies on the appearance of a
We present a quantitative assessment of the value of cooperation for solving constraint satisfact... more We present a quantitative assessment of the value of cooperation for solving constraint satisfaction problems through a series of experiments, as well as a general theory of cooperative problem solving. These experiments, using both hierarchical and non-hierarchical cooperation, clearly exhibit a universal improvement in performance that results from cooperation. We also show both theoretically and ex- perimentally the super-linear speed-up
Uploads
Papers by Bernardo Huberman