Random hypergraphs and their applications

In the last few years we have witnessed the emergence, primarily in on-line communities, of new types of social networks that require for their representation more complex graph structures than have been employed in the past. One example is the folksonomy, a tripartite structure of users, resources, and tags -- labels collaboratively applied by the users to the resources in order to impart meaningful structure on an otherwise undifferentiated database. Here we propose a mathematical model of such tripartite structures which represents them as random hypergraphs. We show that it is possible to calculate many properties of this model exactly in the limit of large network size and we compare the results against observations of a real folksonomy, that of the on-line photography web site Flickr. We show that in some cases the model matches the properties of the observed network well, while in others there are significant differences, which we find to be attributable to the practice of multiple tagging, i.e., the application by a single user of many tags to one resource, or one tag to many resources.Comment: 11 pages, 7 figure

Wear Minimization for Cuckoo Hashing: How Not to Throw a Lot of Eggs into One Basket

We study wear-leveling techniques for cuckoo hashing, showing that it is possible to achieve a memory wear bound of $\log\log n+O(1)$ after the insertion of $n$ items into a table of size $Cn$ for a suitable constant $C$ using cuckoo hashing. Moreover, we study our cuckoo hashing method empirically, showing that it significantly improves on the memory wear performance for classic cuckoo hashing and linear probing in practice.Comment: 13 pages, 1 table, 7 figures; to appear at the 13th Symposium on Experimental Algorithms (SEA 2014

Beyond the Stalemate of Economics versus Ethics: Corporate Social Responsibility and the Discourse of the Organizational Self

The purpose of this paper is to advance research on CSR beyond the stalemate of economic versus ethical models by providing an alternative perspective integrating existing views and allowing for more shared dialog and research in the field. It is suggested that we move beyond making a normative case for ethical models and practices of CSR by moving beyond the question of how to manage organizational self-interest toward the question of how accurate current conceptions of the organizational self seem to be. Specifically, it is proposed that CSR is not a question of how self-interested the corporation should be, but how this self is defined. Economic and ethical models of CSR are not models of opposition but exist on a continuum between egoic and post-egoic, illusory and authentic conceptions of the organizational self. This means that moving from one to the other is not a question of adopting different paradigms but rather of moving from illusion and dysfunction to authenticity and functionality, from pathology to health. Copyright Springer 2006corporate social responsibility, economic and ethical models, economic, egoic and post-egoic approaches, narratives, organizational self, psychoanalysis,