This project gives a general definition of communities in the context of communication networks, an important and well-studied category of social networks. Our work mathematically justifies the claim that sparse network ties, as opposed to tightly structured solidarity groups, can form a foundation for locating social communities. We develop and test a model of communities based on a novel set ...

In 1988, Nemhauser and Wolsey introduced the concept of MIR inequality for mixed integer linear programs. In 1998, Wolsey defined MIR inequalities differently. In some sense these definitions are equivalent. However, this note points out that the natural concepts of MIR closures derived from these two definitions are distinct. Dash, Günlük and Lodi made the same observation independently. Let S...

Social networks exhibit scaling laws for several structural characteristics, such as degree distribution, scaling of the attachment kernel and clustering coefficients as a function of node degree. A detailed understanding if and how these scaling laws are inter-related is missing so far, let alone whether they can be understood through a common, dynamical principle. We propose a simple model fo...

In the past decade, two topics have generated much interest in the idea of social networks and network analysis. These are social capital, popularised by Robert Putnam, and small-worlds, popularised by Duncan Watts and Albert-László Barabási. Social capital highlights local processes and network structures, theorizing the ways in which relations and their patterns link individuals and groups to...

purpose: to evaluate the effect of phacoemulsification and posterior chamber intraocular lens (pciol) implantation on intraocular pressure (iop) in eyes with chronic angle-closure glaucoma. methods: twenty-two patients with chronic angle-closure glaucoma (cacg) and visually significant cataract were included in our study. all were underwent phacoemulsification and pciol implantation. iop, depth...

Understanding how information technology (IT) transforms individual, organizational, and societal ways of being is becoming increasingly complex and discourses on IT present opportunity and risk as two inseparable sides of the same phenomenon. Among the themes that extend throughout practitioner literature, and have emerged gradually in the academic literature as well, ERP projects are illustra...

A framing effect occurs when an agent’s choices are not invariant under changes in the way a decision problem is presented, e.g. changes in the way options are described (violation of description invariance) or preferences are elicited (violation of procedure invariance). Here we identify those rationality violations that underlie framing effects. Applying a model by List (2004), we attribute t...

There is a growing recognition in communities across the globe, which a fundamental rebellion is brewing. This challenge to convention reflects two fundamental tenets: (a) that the essential activity of being human is not the setting and seeking of goals of resource allocation, but the establishment and maintenance of relationships; and (b) that learning about our world involves experience, spi...

A framing effect occurs when an agent’s choices are not invariant under changes in the way a decision problem is presented, e.g. changes in the way options are described (violation of description invariance) or preferences are elicited (violation of procedure invariance). Here we identify those rationality violations that underlie framing effects. Applying a model by List (2004), we attribute t...

The study of triangles in graphs is a standard tool in network analysis. Real-world networks are often directed and have a significant fraction of reciprocal edges. Direction leads to many complexities, and it can be difficult to “measure” this structure meaningfully. We propose a collection of directed closure values that are analogues of the classic transitivity measure (the fraction of wedge...