NAVIGATION WITHOUT LOGARITHMS

Navigation without Localisation: A Reactive Network Approach

In this paper, we address the following problem: given a robot which is at some unknown location in a known environment, how does the robot go about reaching its goal? In resolving this problem, we have abandoned the notion of localisation and instead developed the concept of a reactive network. A reactive network is simply a specialized kind of nite state machine whose states correspond to act...

O(1) Reversible Tree Navigation Without Cycles

Imperative programmers often use cyclically linked trees in order to achieve O(1) navigation time to neighbours. Some logic programmers believe that cyclic terms are necessary to achieve the same in logic-based languages. An old but little-known technique provides O(1) time and space navigation without cyclic links, in the form of reversible predicates. A small modification provides O(1) amorti...

Demo Abstract: Sensor Network Navigation without Locations

Navigation Without Perception of Coordinates and Distances

We consider the target{reaching problem in plane scenes for a point robot which has a tactile sensor and can locate the target ray. It might have a compass, too, but it is not able to perceive the coordinates of its position nor to measure distances. The complexity of an algorithm is measured by the number of straight moves until reaching the target, as a function of the number of vertices of t...

Natural logarithms

Marusic et al. (J. Fluid Mech., vol. 716, 2013, R3) show the first clear evidence of universal logarithmic scaling emerging naturally (and simultaneously) in the mean velocity and the intensity of the streamwise velocity fluctuations about that mean in canonical turbulent flows near walls. These observations represent a significant advance in understanding of the behaviour of wall turbulence at...