On the Equivalence of Cellular Automata and the Tile Assembly Model

In this paper, we explore relationships between two models of systems which are governed by only the local interactions of large collections of simple components: cellular automata (CA) and the abstract Tile Assembly Model (aTAM). While sharing several similarities, the models have fundamental differences, most notably the dynamic nature of CA (in which every cell location is allowed to change state an infinite number of times) versus the static nature of the aTAM (in which tiles are static components that can never change or be removed once they attach to a growing assembly). We work with 2-dimensional systems in both models, and for our results we first define what it means for CA systems to simulate aTAM systems, and then for aTAM systems to simulate CA systems. We use notions of simulate which are similar to those used in the study of intrinsic universality since they are in some sense strict, but also intuitively natural notions of simulation. We then demonstrate a particular nondeterministic CA which can be configured so that it can simulate any arbitrary aTAM system, and finally an aTAM tile set which can be configured so that it can be used to simulate any arbitrary nondeterministic CA system which begins with a finite initial configuration.Comment: In Proceedings MCU 2013, arXiv:1309.104

Genus Computing for 3D digital objects: algorithm and implementation

This paper deals with computing topological invariants such as connected components, boundary surface genus, and homology groups. For each input data set, we have designed or implemented algorithms to calculate connected components, boundary surfaces and their genus, and homology groups. Due to the fact that genus calculation dominates the entire task for 3D object in 3D space, in this paper, we mainly discuss the calculation of the genus. The new algorithms designed in this paper will perform: (1) pathological cases detection and deletion, (2) raster space to point space (dual space) transformation, (3) the linear time algorithm for boundary point classification, and (4) genus calculation.Comment: 12 pages 7 figures. In Proceedings of the Workshop on Computational Topology in image context 2009, Aug. 26-28, Austria, Edited by W. Kropatsch, H. M. Abril and A. Ion, 200

Zeitkippen : Begleitpublikation zum Film C 13075

If we see a film, we experience the passing time in two ways. On the one hand, it is conveyed as the time in which the film action takes place – felt as “lived” time. On the other hand, via camera travels and movements of objects vertically to the picture plane, time is perceived – in a much more indirect way – as a vehicle for representation of spatial depth. It is this link between space and time where the method of “time tilting” introduced here sets in. When a film scene is “time-tilted”, one of the spatial dimensions (here the horizontal direction of the picture plane) is interchanged with the time dimension: In a first step, the pictures of the scene are digitalized. Then, the thus gained pixels of all pictures of the scene are arranged into a three-dimensional data field. Finally, a new series of pictures is read out, along one of the two former picture axes, which is then shown as a scene of moving pictures. The resulting film will present optical phenomena which are, on the one hand, aesthetically appealing and, on the other hand, informative for film analysis. First examples demonstrate how the procedure operates on basic movements in space as well as on camera travels in space.Bei der Vorführung eines Films wirkt die ablaufende Zeit auf den Zuschauer in zweierlei Weise. Zum einen als die Zeit, in der die Filmhandlung stattfindet und die als gelebte Zeit empfunden wird. Zum anderen, sehr viel indirekter, als Vehikel zur Darstellung von Raumtiefe durch Kamerafahrten und Objektbewegungen senkrecht zur Bildebene. An dieser Verknüpfung von Raum und Zeit setzt die hier vorgestellte Methode „Zeitkippen“ an. Beim Zeitkippen einer Filmszene wird eine der Raumdimensionen (hier die Horizontale der Bildebene) mit der Zeitachse vertauscht: Im ersten Schritt digitalisiert man die Szene. Dann fügt man die Bildpunkte (Pixel) aller Szenen bilder in ein dreidimensionales Datenfeld. Schließlich liest man entlang einer der beiden ehemaligen Bildfeldachsen eine neue Bildserie aus, die man als Bewegtbild-Szene vorführt. Dabei entstehen einerseits ästhetisch ansprechende und andererseits filmanalytisch auf schlussreiche optische Phänomene. Erste Beispiele zeigen, wie sich das Verfahren auf grundlegende Bewegungen im Raum sowie Kamerafahrten im Raum auswirkt

Fast connected component labeling algorithm: a non voxel-based approach

This paper presents a new approach to achieve connected component labeling on both binary images and volumes by using the Extreme Vertices Model (EVM), a representation model for orthogonal polyhedra, applied to digital images and volume datasets recently. In contrast with previous techniques, this method does not use a voxel-based approach but deals with the inner sections of the object.Postprint (published version

Studies of Prototype CsI(Tl) Crystal Scintillators for Low-Energy Neutrino Experiments

Crystal scintillators provide potential merits for the pursuit of low-energy low-background experiments. A CsI(Tl) scintillating crystal detector is being constructed to study low-energy neutrino physics at a nuclear reactor, while projects are underway to adopt this technique for dark matter searches. The choice of the geometrical parameters of the crystal modules, as well as the optimization of the read-out scheme, are the results of an R&D program. Crystals with 40 cm in length were developed. The detector requirements and the achieved performance of the prototypes are presented. Future prospects for this technique are discussed.Comment: 32 pages, 14 figure