California freeway travelers suffer large and variable congestion delay. The delay is due to operational inefficiency, excess demand, and unforseen events. Operational inefficiency reduces speed and may cause queue spillovers that reduce exiting flows. Excess demand creates delay on ramps. Unforseen events such as accidents temporarily reduce capacity. The Cell Transmission Model of a freeway w...

Early vision is best understood in terms of two key information bottlenecks along the visual pathway -- the optic nerve and, more severely, attention. Two effective strategies for sampling and representing visual inputs in the light of the bottlenecks are (1) data compression with minimum information loss and (2) data deletion. This paper reviews two lines of theoretical work which understand p...

A key goodness metric of multi-threaded programs is how their execution times scale when increasing the number of threads. However, there are several bottlenecks that can limit the scalability of a multi-threaded program, e.g., contention for shared cache capacity and off-chip memory bandwidth; and synchronization overheads. In order to improve the scalability of a multi-threaded program, it is...

This study presents a surrogate safety measure for evaluating the rear-end collision risk related to kinematic waves near freeway recurrent bottlenecks using aggregated traffic data from ordinary loop detectors. The attributes of kinematic waves that accompany rear-end collisions and the traffic conditions at detector stations spanning the collision locations were examined to develop the rear-e...

Performance can be a critical aspect of software quality ; in some systems, poor performance can cause-nancial loss, physical damage, or even death. In such cases, it is imperative to identify system performance problems before deployment, preferably well before implementation. Unfortunately, the size of most software systems grossly exceeds the capacity of current performance-modelling techniq...

Bottlenecks in population size reduce genetic diversity and increase inbreeding, which can lead to inbreeding depression. It is thus puzzling how introduced species, which typically pass through bottlenecks, become such successful invaders. However, under certain theoretical conditions, bottlenecks of intermediate size can actually purge the alleles that cause inbreeding depression. Although th...