Random walk is a powerful tool, not only for modeling, but also for practical use such as the Internet crawlers. Standard random walks on graphs have been well studied; It is well-known that both hitting time and cover time of a standard random walk are bounded by O(n) for any graph with n vertices, besides the bound is tight for some graphs. Ikeda et al. (2003) provided “β-random walk,” which ...

A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. Hitting times for discrete quantum walks on graphs give an average time before the walk reaches an ending condition. We derive an expression for hitting time using superoperators, and numerically evaluate it for the walk on the hypercube for various ...

We are going to analyze simple search tree algorithms for Weighted d-Hitting Set. Although the algorithms are simple, their analysis is technically rather involved. However, this approach allows us to even improve on elsewhere previously published running time estimates for the more restricted case of (unweighted) d-Hitting Set. 1

We are going to analyze simple search tree algorithms for Weighted d-Hitting Set. Although the algorithms are simple, their analysis is technically rather involved. However, this approach allows us to even improve on elsewhere previously published running time estimates for the more restricted case of (unweighted) d-Hitting Set. 1

Given a dynamical system and a subset A of its phase space, we consider those orbits which, on average, spend as long as possible in A. This largest possible average is the maximum hitting frequency. We study the variation of the (orbits of) maximum hitting frequency as a function of A. Mathematics Subject Classification: 37A, 37B20

An 'oscillating' version of Brownian motion is defined and studied. 'Ordinary' Brownian motion and 'reflecting' Brownian motion are shown to arise as special cases. Transition densities, first-passage time distributions, and occupation time distributions for the process are obtained explicitly. Convergence of a simple oscillating random walk to an oscillating Brownian motion process is establis...

We consider the following basic task in the testing of concurrent systems. The input to the task is a partial order of events, which models actions performed on or by the system and specifies ordering constraints between them. The task is to determine if some scheduling of these events can result in a bug. The number of schedules to be explored can, in general, be exponential. Empirically, many...

BACKGROUND Grip size of a tennis racquet has been reported to influence performance, but clear evidence of a correlation has yet to be established. HYPOTHESIS Hitting force during a soft tennis forehand stroke correlates with grip size. STUDY DESIGN Controlled clinical study. METHODS A total of 40 healthy volunteers (20 men and 20 women) with a mean age of 21.9 years were enrolled. Of the...

We consider the problem of hitting sets online. The hypergraph (i.e., rangespace consisting of points and ranges) is known in advance, and the ranges to be stabbed are input one-by-one in an online fashion. The online algorithm must stab each range upon arrival. An online algorithm may add points to the hitting set but may not remove already chosen points. The goal is to use the smallest number...

We consider general quantum random walks in a d-dimensional half-space. We first obtain a path integral formula for general quantum random walks in a d-dimensional space. Our path integral formula is valid for general quantum random walks on Cayley graphs as well. Then the path integral formula is applied to obtain the scaling limit of the exit distribution, the expectation of exit time and the...