1,398 research outputs found
Simulating spin systems on IANUS, an FPGA-based computer
We describe the hardwired implementation of algorithms for Monte Carlo
simulations of a large class of spin models. We have implemented these
algorithms as VHDL codes and we have mapped them onto a dedicated processor
based on a large FPGA device. The measured performance on one such processor is
comparable to O(100) carefully programmed high-end PCs: it turns out to be even
better for some selected spin models. We describe here codes that we are
currently executing on the IANUS massively parallel FPGA-based system.Comment: 19 pages, 8 figures; submitted to Computer Physics Communication
Complexity results for three-dimensional orthogonal graph drawing
AbstractIn this paper we consider the problem of finding three-dimensional orthogonal drawings of maximum degree six graphs from the computational complexity perspective. We introduce a 3SAT reduction framework that can be used to prove the NP-hardness of finding three-dimensional orthogonal drawings with specific constraints. By using the framework we show that, given a three-dimensional orthogonal shape of a graph (a description of the sequence of axis-parallel segments of each edge), finding the coordinates for nodes and bends such that the drawing has no intersection is NP-complete. Conversely, we show that if node coordinates are fixed, finding a shape for the edges that is compatible with a non-intersecting drawing is a feasible problem, which becomes NP-complete if a maximum of two bends per edge is allowed. We comment on the impact of these results on the two open problems of determining whether a graph always admits a drawing with at most two bends per edge and of characterizing orthogonal shapes admitting an orthogonal drawing without intersections
Context classification for service robots
This dissertation presents a solution for environment sensing using sensor fusion techniques and a context/environment classification of the surroundings in a service robot, so it could change his behavior according to the different rea-soning outputs.
As an example, if a robot knows he is outdoors, in a field environment, there can be a sandy ground, in which it should slow down. Contrariwise in indoor environments, that situation is statistically unlikely to happen (sandy ground). This simple assumption denotes the importance of context-aware in automated guided vehicles
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