| 1. |
- Benkner, S., et al.
(författare)
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Peppher: Performance Portability and Programmability for Heterogeneous Many-Core Architectures
- 2017
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Ingår i: Programming Multicore and Many-Core Computing Systems. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781119332015 - 9780470936900 ; , s. 241-260
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- © 2017 by John Wiley & Sons, Inc. All rights reserved. PEPPHER takes a pluralistic and parallelization agnostic approach to programmability and performance portability for heterogeneous many-core architectures. The PEPPHER framework is in principle language independent but focuses on supporting C++ code with PEPPHER-specific annotations as pragmas or external annotations. The framework is open and extensible; the PEPPHER methodology details how new architectures are incorporated. The PEPPHER methodology consists of rules for how to extend the framework for new architectures. This mainly concerns adaptivity and autotuning for algorithm libraries, the necessary hooks and extensions for the run-time system and any supporting algorithms and data structures that this relies on. Offloading is a specific technique for programming heterogeneous platforms that can sometimes be applied with high efficiency. Offload as developed by the PEPPHER partner Codeplay is a particular, nonintrusive C++ extension allowing portable C++ code to support diverse heterogeneous multicore architectures in a single code base.
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| 2. |
- Chen, Yousheng, 1985-, et al.
(författare)
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A Pretest Planning Method for Model Calibration for Nonlinear Systems
- 2016
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Ingår i: Model Validation and Uncertainty Quantification, Volume 3. - Cham : Springer. - 2191-5644 .- 2191-5652. - 9783319297538 - 9783319297545 ; , s. 371-379
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With increasing demands on more flexible and lighter engineering structures, it has been more common to take nonlinearity into account. Model calibration is an important procedure for nonlinear analysis in structural dynamics with many industrial applications. Pretest planning plays a key role in the previously proposed calibration method for nonlinear systems, which is based on multi-harmonic excitation and an effective optimization routine. This paper aims to improve the pretest planning strategy for the proposed calibration method. In this study, the Fisher information matrix (FIM), which is calculated from the gradients with respect to the chosen parameters with unknown values, is used for determining the locations, frequency range, and the amplitudes of the excitations as well as the sensor placements. This pretest planning based model calibration method is validated by a structure with clearance nonlinearity. Synthetic test data is used to simulate the test procedure. Model calibration and K-fold cross validation are conducted for the optimum configurations selected from the pretest planning as well as three other configurations. The calibration and cross validation results show that a more accurate estimation of parameters can be obtained by using test data from the optimum configuration.
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| 3. |
- Chen, Yousheng, 1985-, et al.
(författare)
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An Efficient Simulation Method for Large-Scale Systems with Local Nonlinearities
- 2016
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Ingår i: Special topics in structural dynamics, 34th IMAC. - Cham : Springer. - 2191-5644 .- 2191-5652. - 9783319299105 - 9783319299099
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In practice, most mechanical systems show nonlinear characteristics within the operational envelope. However, the nonlinearities are often caused by local phenomena and many mechanical systems can be well represented by a linear model enriched with local nonlinearities. Conventional nonlinear response simulations are often computationally intensive; the problem which becomes more severe when large-scale nonlinear systems are concerned. Thus, there is a need to further develop efficient simulation techniques. In this work, an efficient simulation method for large-scale systems with local nonlinearities is proposed. The method is formulated in a state-space form and the simulations are done in the Matlab environment. The nonlinear system is divided into a linearized system and a nonlinear part represented as external nonlinear forces acting on the linear system; thus taking advantage in the computationally superiority in the locally nonlinear system description compared to a generally nonlinear counterpart. The triangular-order hold exponential integrator is used to obtain a discrete state-space form. To shorten the simulation time additionally, auxiliary matrices, similarity transformation and compiled C-codes (mex) to be used for the time integration are studied. Comparisons of the efficiency and accuracy of the proposed method in relation to simulations using the ODE45 solver in Matlab and MSC Nastran are demonstrated on numerical examples of different model sizes.
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| 4. |
- Chen, Yousheng, 1985-, et al.
(författare)
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Model calibration of locally nonlinear structures using information from sub and super harmonic responses
- 2012
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Ingår i: International Conference on Noise and Vibration Engineering 2012 (ISMA 2012). - Leuven : Katholieke Universiteit Leuven, Department of Mechanical Engineering. - 9781622768257 ; , s. 2451-2464
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Large linear finite element models are commonly used in industry to represent global structural behavior and such models are often validated by use of data from vibrational tests. The validated models serve to predict the structural responses due to dynamic loads. Hence, it is important to have models that are able to represent the structural dynamics within the given operating envelope. When test data show proof of non linear behavior, a linear model may not be able to represent the dynamics well enough and thus a modification of the model is required. The main part of the structure may have a linear characteristic whereas localized physical processes can be sources of the observed nonlinearities. Model calibration of such locally nonlinear structures is studied in this paper. Specifically, the calibration process including the selection of appropriate data to be used for calibration of the model parameters chosen is treated. Here, synthetic test data stemming from a model of the Ecole Centrale de Lyon (ECL) nonlinear benchmark are used.
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| 5. |
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| 6. |
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| 7. |
- Fhager, Andreas, 1976, et al.
(författare)
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A statistical approach to gradient scaling microwave tomography
- 2007
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Ingår i: Proceedings of EMB 07, computational electromagnetis, methods and applications, Lund, Sweden. ; , s. 153-160, s. 153-160, s. 153-160
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Fhager, Andreas, 1976, et al.
(författare)
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A Statistically Based Preconditioner for Two-Dimensional Microwave Tomography
- 2007
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Ingår i: Proceedings of The Second International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP2007), Dec. 12-14 2007, St. Thomas, U.S. Virgin Islands. - 9781424417148 ; , s. 173-176
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Geissinger, Andrea, 1987-, et al.
(författare)
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Tracking the institutional logics of the sharing economy
- 2019
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Ingår i: Handbook of the Sharing Economy. - Cheltenham : Edward Elgar Publishing. - 9781788110549 - 9781788110532 ; , s. 177-192
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter explores field-level logics associated with the sharing economy and how these logics can be categorized in relation to different characteristic features of that economy. It thereby links together core principles of the sharing economy-the access, platform and community-based economy-with market and non-market orders so as to create a better understanding for those tensions being part of the sharing economy and how they can be overcome. Empirically, the chapter analyzes 7362 social media posts and defines field-level logics through juxtaposing the core principles with market/non-market orders. Six field-level logics are identified: abundance, scarcity, profit, sustainability, global and local logics. The sorting tool of these field-level logics and their associated institutional orders provides clarity in relation to the blurred concepts of accessing, sharing and transferring; the variety of motives of users/consumers; and the reasons for parties to provide their services within the sharing economy. The chapter also contributes to previous research through linking together field-level logics with orders to create understandings for logics on phenomena levels and specifically related to the sharing economy.
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| 10. |
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