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Time Performance (time + performance)

Distribution by Scientific Domains

Information Science and Computing	75%

Selected Abstracts

A Multiresolution Model for Soft Objects Supporting Interactive Cuts and Lacerations

COMPUTER GRAPHICS FORUM, Issue 3 2000
Fabio Ganovelli
Performing a really interactive and physically-based simulation of complex soft objects is still an open problem in computer animation/simulation. Given the application domain of virtual surgery training, a complete model should be quite realistic, interactive and should enable the user to modify the topology of the objects. Recent papers propose the adoption of multiresolution techniques to optimize time performance by representing at high resolution only the object parts considered more important or critical. The speed up obtainable at simulation time are counterbalanced by the need of a preprocessing phase strongly dependent on the topology of the object, with the drawback that performing dynamic topology modification becomes a prohibitive issue. In this paper we present an approach that couples multiresolution and topological modifications, based on the adoption of a particle systems approach to the physical simulation. Our approach is based on a tetrahedral decomposition of the space, chosen both for its suitability to support a particle system and for the ready availability of many techniques recently proposed for the simplification and multiresolution management of 3D simplicial decompositions. The multiresolution simulation system is designed to ensure the required speedup and to support dynamic changes of the topology, e.g. due to cuts or lacerations of the represented tissue. [source]

High-level distribution for the rapid production of robust telecoms software: comparing C++ and ERLANG

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 8 2008
J. H. Nyström
Abstract Currently most distributed telecoms software is engineered using low- and mid-level distributed technologies, but there is a drive to use high-level distribution. This paper reports the first systematic comparison of a high-level distributed programming language in the context of substantial commercial products. Our research strategy is to reengineer some C++/CORBA telecoms applications in ERLANG, a high-level distributed language, and make comparative measurements. Investigating the potential advantages of the high-level ERLANG technology shows that two significant benefits are realized. Firstly, robust configurable systems are easily developed using the high-level constructs for fault tolerance and distribution. The ERLANG code exhibits resilience: sustaining throughput at extreme loads and automatically recovering when load drops; availability: remaining available despite repeated and multiple failures; dynamic reconfigurability: with throughput scaling near-linearly when resources are added or removed. Secondly, ERLANG delivers significant productivity and maintainability benefits: the ERLANG components are less than one-third of the size of their C++ counterparts. The productivity gains are attributed to specific language features, for example, high-level communication saves 22%, and automatic memory management saves 11%,compared with the C++ implementation. Investigating the feasibility of the high-level ERLANG technology demonstrates that it fulfils several essential requirements. The requisite distributed functionality is readily specified, even although control of low-level distributed coordination aspects is abrogated to the ERLANG implementation. At the expense of additional memory residency, excellent time performance is achieved, e.g. three times faster than the C++ implementation, due to ERLANG's lightweight processes. ERLANG interoperates at low cost with conventional technologies, allowing incremental reengineering of large distributed systems. The technology is available on the required hardware/operating system platforms, and is well supported. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A comparison of concurrent programming and cooperative multithreading

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2003
Aaron W. Keen
Abstract This paper presents a comparison of the cooperative multithreading model with the general concurrent programming model. It focuses on the execution time performance of a range of standard concurrent programming applications. The overall results are mixed. In some cases, programs written in the cooperative multithreading model outperform those written in the general concurrent programming model. The contributions of this paper are twofold. First, it presents a thorough analysis of the performances of applications in the different models, i.e. to explain the criteria that determine when a program in one model will outperform an equivalent program in the other. Second, it examines the tradeoffs in writing programs in the different programming styles. In some cases, better performance comes at the cost of more complicated code. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Longtime performance and reliability of two different PtcCO2 and SpO2 sensors in neonates

PEDIATRIC ANESTHESIA, Issue 9 2008
VERA BERNET
Summary Objectives:, Blood gas monitoring is necessary in treatment of critically ill neonates. Whereas SaO2 can be estimated by pulse oximetry, PaCO2 is still most often assessed from blood samples. Aim:, To compare long time performance of an ear sensor for combined assessment of transcutaneous carbon dioxide (PtcCO2) and oxygen saturation (SpO2) (TOSCA Monitor; Radiometer, Switzerland) with a conventional PtcCO2 monitor (MicroGas 7650-500 rapid, Radiometer, Switzerland) in critically ill neonates. Methods:, Prospective, observational study. Twenty critically ill neonates were monitored for PtcCO2 and SpO2 using the Tosca and the MicroGas monitor for 24 h. TOSCA ear sensor was changed to the other ear lobe after 12 h and the MicroGas sensor four hourly on the trunk. Values obtained were compared with SaO2 and PaCO2 from arterial blood gas analysis using Bland,Altman analysis. Data are presented as median (range). Results:, Eighty-two paired measurements were obtained. Median age of the 20 patients was 4.5 days (1,26 days) and weight was 3.05 kg (0.98,3.95 kg). Bias and precision between PaCO2 and PtcCO2 were 0.14 and 1.45 kPa for the Tosca monitor and ,0.08 and 1.2 kPa for the MicroGas monitor, respectively. The two biases were significantly different (P = 0.0036). SpO2 assessment by TOSCA was comparable to SaO2 values (bias 0.26% and precision 4.14%). Conclusion:, The TOSCA monitor allows safe estimation of PtcCO2 and SaO2 in neonates. Measurements of PtcCO2 were less reliable with TOSCA compared with conventional monitoring but still allow assessing a trend of ventilation status in newborn patients. [source]