Random Ramblings: Rational Individual Decisions that Lead to Irrational Global Consequences

Rational decisions, random matrices and spin glasses

We consider the problem of rational decision making in the presence of nonlinear constraints. By using tools borrowed from spin glass and random matrix theory, we focus on the portfolio optimisation problem. We show that the number of optimal solutions is generally exponentially large, and each of them is fragile: rationality is in this case of limited use. In addition, this problem is related ...

Rational and Irrational Bubbles

The rational approach to the irrational.

American AssociaUon for the Advancemnt of Science Science serves its readers as a forum for the presentation and discussion of important issues related to the advancement of science, including the presentation of minority or conflicting points of view, rather than by publishing only material on which a consensus has been reached. Accordingly, all articles published in Science-including editoria...

Dengue vaccine: local decisions, global consequences

As new vaccines against diseases that are prevalent in low- and middle-income countries gradually become available, national health authorities are presented with new regulatory and policy challenges. The use of CYD-TDV - a chimeric tetravalent, live-attenuated dengue vaccine - was recently approved in five countries. Although promising for public health, this vaccine has only partial and heter...

The splitting design that leads to simple random sampling

Implementing unequal probability sampling, without replacement, is very complex and several methods have been suggested for its performance, including : Midseno design and systematic design. One of the methods that have been introduced by Devil and Tille (1998) is the splitting design that leads to simple random sampling .in this paper by completely explaining the design, with an example, we ha...