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Prototype Implementation (prototype + implementation)
Selected AbstractsEmbedded Implicit Stand-Ins for Animated Meshes: A Case of Hybrid ModellingCOMPUTER GRAPHICS FORUM, Issue 1 2010D. Kravtsov Abstract In this paper, we address shape modelling problems, encountered in computer animation and computer games development that are difficult to solve just using polygonal meshes. Our approach is based on a hybrid-modelling concept that combines polygonal meshes with implicit surfaces. A hybrid model consists of an animated polygonal mesh and an approximation of this mesh by a convolution surface stand-in that is embedded within it or is attached to it. The motions of both objects are synchronised using a rigging skeleton. We model the interaction between an animated mesh object and a viscoelastic substance, which is normally represented in an implicit form. Our approach is aimed at achieving verisimilitude rather than physically based simulation. The adhesive behaviour of the viscous object is modelled using geometric blending operations on the corresponding implicit surfaces. Another application of this approach is the creation of metamorphosing implicit surface parts that are attached to an animated mesh. A prototype implementation of the proposed approach and several examples of modelling and animation with near real-time preview times are presented. [source] JaMP: an implementation of OpenMP for a Java DSMCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 18 2007Michael Klemm Abstract Although OpenMP is a widely agreed-upon standard for the C/C++ and Fortran programming languages for the semi-automatic parallelization of programs for shared memory machines, not much has been done on the binding of OpenMP to Java that targets clusters with distributed memory. This paper presents three major contributions: (1) JaMP is an adaptation of the OpenMP standard to Java that implements a large subset of the OpenMP specification with an expressiveness comparable to that of OpenMP; (2) we suggest a set of extensions that allow a better integration of OpenMP into the Java language; (3) we present our prototype implementation of JaMP in the research compiler Jackal, a software-based distributed shared memory implementation for Java. We evaluate the performance of JaMP with a set of micro-benchmarks and with OpenMP versions of the parallel Java Grande Forum (JGF) benchmarks. The micro-benchmarks show that OpenMP for Java can be implemented without much overhead. The JGF benchmarks achieve a good speed-up of 5,8 on eight nodes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Seine: a dynamic geometry-based shared-space interaction framework for parallel scientific applicationsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 15 2006L. Zhang Abstract While large-scale parallel/distributed simulations are rapidly becoming critical research modalities in academia and industry, their efficient and scalable implementations continue to present many challenges. A key challenge is that the dynamic and complex communication/coordination required by these applications (dependent on the state of the phenomenon being modeled) are determined by the specific numerical formulation, the domain decomposition and/or sub-domain refinement algorithms used, etc. and are known only at runtime. This paper presents Seine, a dynamic geometry-based shared-space interaction framework for scientific applications. The framework provides the flexibility of shared-space-based models and supports extremely dynamic communication/coordination patterns, while still enabling scalable implementations. The design and prototype implementation of Seine are presented. Seine complements and can be used in conjunction with existing parallel programming systems such as MPI and OpenMP. An experimental evaluation using an adaptive multi-block oil-reservoir simulation is used to demonstrate the performance and scalability of applications using Seine. Copyright © 2006 John Wiley & Sons, Ltd. [source] Middleware for real-time distributed simulationsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 15 2004Thom McLean Abstract Distributed simulation applications often rely on middleware to provide services to support their execution over distributed computing environments. Such middleware spans many levels, ranging from low-level support for data transmission through object request brokers to higher level, simulation specific functionality such as time management. We discuss design alternatives for realizing such middleware for hard real-time distributed simulations such as hardware-in-the-loop applications. We present the results from tests of a prototype implementation of real-time Run-Time Infrastructure middleware. Its performance is compared with a non-real-time implementation. The context for this work is the High Level Architecture standard that has been defined by the U.S. Department of Defense. Copyright © 2004 John Wiley & Sons, Ltd. [source] Proxy caching algorithms and implementation for time-shifted TV servicesEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2008Tim Wauters The increasing popularity of multimedia streaming applications introduces new challenges in content distribution networks (CDNs). Streaming services such as Video on Demand (VoD) or digital television over the Internet (IPTV) are very bandwidth-intensive and cannot tolerate the high start-up delays and poor loss properties of today's Internet. To solve these problems, caching (the initial segment of) popular streams at proxies could be envisaged. This paper presents a novel caching algorithm and architecture for time-shifted television (tsTV) and its implementation, using the IETF's Real-Time Streaming Protocol (RTSP). The algorithm uses sliding caching windows with sizes depending on content popularity and/or distance metrics. The caches can work in stand-alone mode as well as in co-operative mode. This paper shows that the network load can already be reduced considerably using small diskless caches, especially when using co-operative caching. A prototype implementation is detailed and evaluated through performance measurements. Copyright © 2007 John Wiley & Sons, Ltd. [source] Encoding of electrophysiology and other signals in MR imagesJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2007Lars G. Hanson PhD Abstract Purpose To develop a gradient insensitive, generic technique for recording of non-MR signals by use of surplus scanner bandwidth. Materials and Methods Relatively simple battery driven hardware is used to transform one or more signals into radio waves detectable by the MR scanner. Similar to the "magstripe" technique used for encoding of soundtracks in motion pictures, the electrical signals are in this way encoded as artifacts appearing in the MR images or spectra outside the region of interest. The encoded signals are subsequently reconstructed from the signal recorded by the scanner. Results Electrophysiological (EP) eye and heart muscular recording (electrooculography [EOG] and electrocardiography [ECG]) during fast echo planar imaging (EPI) is demonstrated with an expandable, modular 8-channel prototype implementation. The gradient artifacts that would normally be dominating EOG are largely eliminated. Conclusion The method provides relatively inexpensive sampling with inherent microsecond synchronization and it reduces gradient artifacts in physiological recordings significantly. When oversampling is employed, the method is compatible with all MR reconstruction and postprocessing techniques. J. Magn. Reson. Imaging 2007;25:1059,1066. © 2007 Wiley-Liss, Inc. [source] A query language for discovering semantic associations, Part II: sample queries and query evaluationJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 11 2007Timo Niemi In our query language introduced in Part I (Niemi & Jämsen, in press) the user can formulate queries to find out (possibly complex) semantic relationships among entities. In this article we demonstrate the usage of our query language and discuss the new applications that it supports. We categorize several query types and give sample queries. The query types are categorized based on whether the entities specified in a query are known or unknown to the user in advance, and whether text information in documents is utilized. Natural language is used to represent the results of queries in order to facilitate correct interpretation by the user. We discuss briefly the issues related to the prototype implementation of the query language and show that an independent operation like Rho (Sheth et al., 2005; Anyanwu & Sheth, 2002, 2003), which presupposes entities of interest to be known in advance, is exceedingly inefficient in emulating the behavior of our query language. The discussion also covers potential problems, and challenges for future work. [source] | ||||||||||