Damian Merrick

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We investigate the problem of creating simplified representations of polygonal paths. Specifically, we look at a path simplification problem in which line segments of a simplification are required to conform with a restricted set of directions C. An algorithm is given to compute such simplified paths in O(|C|n) time, where n is the number of vertices in the(More)
In this paper we consider a problem that occurs when drawing public transportation networks. Given an embedded graph G = (V,E) (e.g. the railroad network) and a set H of paths in G (e.g. the train lines), we want to draw the paths along the edges of G such that they cross each other as few times as possible. For aesthetic reasons we insist that the relative(More)
We investigate the new problem of automatic metro map layout. In general, a metro map consists of a set of lines which have intersections or overlaps. We define a set of aesthetic criteria for good metro map layouts and present a method to produce such layouts automatically. Our method uses a variation of the spring algorithm with a suitable preprocessing(More)
A trajectory is a sequence of locations, each associated with a timestamp, describing the movement of a point. Trajectory data is becoming increasingly available and the size of recorded trajectories is getting larger. In this paper we study the problem of compressing planar trajectories such that the most common spatio-temporal queries can still be(More)
In this thesis, we propose a framework for learning based on Hilbert space embedding of distributions. By embedding the distributions via the kernel mean map, we are able to compare distributions by computing their distance in the reproducing Hilbert spaces. We show that learning via mean map leads to both good generalization ability and finite sample(More)
In this paper, we present a case study for the visualisation and analysis of large and complex temporal multivariate networks derived from the Internet Movie DataBase (IMDB). Our approach is to integrate network analysis methods with visualisation in order to address scalability and complexity issues. In particular, we defined new analysis methods such as(More)
The topic of skeletal animation and its associated techniques have previously been applied in the area of animating computer-generated characters for motion pictures and computer games. This paper investigates the use of similar techniques in the scope of exploring three-dimensional visualisations of graphs. A system is discussed which, after generating an(More)
Given a set S of n red and blue points in the plane, a planar bichromatic minimum spanning tree is the shortest possible spanning tree of S, such that every edge connects a red and a blue point, and no two edges intersect. Computing this tree is NP-hard in general. We present an O(n) time algorithm for the special case when all points are in convex(More)
We study the problem of morphing between two polylines that represent linear geographical features like roads or rivers generalized at two different scales. This problem occurs frequently during continuous zooming in interactive maps. Situations in which generalization operators like typification and simplification replace, for example, a series of(More)