^July August – 2009 ^September

We present an algorithm for curve skeleton extraction from imperfect point clouds where large portions of the data may be missing. Our construction is primarily based on a novel notion of generalized rotational symmetry axis (ROSA) of an oriented point set. Specifically, given a subset S of oriented points, we introduce a variational definition for an oriented point that is most rotationally symmetric with respect to S. Our formulation effectively utilizes normal information to compensate for the missing data and leads to robust curve skeleton computation over regions of a shape that are generally cylindrical. We present an iterative algorithm via planar cuts to compute the ROSA of a point cloud. This is complemented by special handling of non-cylindrical joint regions to obtain a centered, topologically clean, and complete 1D skeleton. We demonstrate that quality curve skeletons can be extracted from a variety of shapes captured by incomplete point clouds. Finally, we show how our algorithm assists in shape completion under these challenges by developing a skeleton-driven point cloud completion scheme. Joint work with *Andrea Tagliasacchi - School of Computing Science, Simon Fraser University *Hao Zhang - School of Computing Science, Simon Fraser University *Daniel Cohen-Or - School of Computer Science, Tel-Aviv University

Service-Oriented Architecture (SOA) is the new phase in the evolution of distributed ente rprise applications. It could enable the design and realization of flexible applications across multiple organizations. However, there are many security issues associated with SO A, e.g. trust establishment among actors in an inter-organizational context and its chan nels of communication are more vulnerable. Solutions include the production of numerous, often overlapping security standards by the industry (but there is no clear view of how t o use them), specialized security mechanisms and methodologies. We propose a methodology to design and build secure service-oriented applications. Our approach builds upon Model- Driven Engineering (MDE) and the use of security patterns. We show the methodology and so me of the related patterns we have produced.