Recent advances in petri nets and concurrency

CEUR Workshop Proceeding

Integrated implementation system for pseudodynamic testing

The pseudodynamic test method is a tool for obtaining the non-linear response of structures to transient ground acceleration. The modelling technique relies on representing the inertial and viscous damping components of the equation of motion computationally, while obtaining a measure of the non-linear elastic restoring forces experimentally. A pseudodynamic implementation system is presented, displaying innovations within both the computational and experimental domains. A SDOF pseudodynamic test facility has been designed and manufactured employing a computer controlled servo-hydraulic actuator system. The experimental facility enables displacements of up to 50mm under forces of up to 50kN with all required instrumentation. The experimental apparatus is controlled by algorithms running in the LabView environment, fully integrated within the execution system, rendering the requirement for a hardware controller obsolete. The execution system allows interactive control of the experiments, and offers a large range options with respect to both control and time integration. The execution routine incorporates both the time integration and control algorithms, and combines these such that they effectively execute as an integrated system. This enables semi-continuous implementation of the pseudodynamic tests with very limited resources. A novel, integral form time stepping scheme is proposed, based on an explicit integral form algorithm (Chang et al. 1998) and the Newmark Implicit scheme. The proposed formulation offers an implicit, and thus unconditionally stable alternative to Chang's algorithm without introducing further approximations. This yields improved dissipation and accuracy properties in addition to enabling combination of the integral form schemes' advantages of representing non-linear force variations during a time step with an unlimited time step size. The improvements have been shown both through analytical analyses and numerical examples in linear and non-linear systems. Implementation of the implicit integral form algorithm has been enabled by coding parts of the algorithm directly into the digital controller

Correctness of model-based software composition (CMC). Proceedings. ECOOP 2003 Workshop #11 in association with the 17th European Conference on Object-Oriented Programming, Darmstadt, Germany, July 22, 2003

This proceedings contains the contributions to the Workshop on Correctness of Model-based Software Composition, held in conjunction with the 17th European Conference on Object-Oriented Programming (ECOOP), Darmstadt, Germany on July 22, 2003. While most events concentrate on realisations of composition on the technological level this workshop aims at closing the gap of ensuring the intended composition result supported by the usage of models. Two important problems in composition are first how to model the different assets (such as components, features or aspects) and second the composition of assets such that consistency and correctness is guaranteed. The first problem has been addressed in the Workshop on Model-based Software Reuse (ECOOP 2002). The latter problem occurs when dealing with, e.g., component interoperability, aspect weaving, feature interaction and (on a more abstract level) traceability between different views or models. One approach to deal with the composition problem is to use models allowing to model the composition. This allows checking the interoperability of the different assets to compose, the correctness of the configuration of assets and predicting properties of the assembled system (especially compliance with user requirements). In case of problem detection suitable resolution algorithms can be applied. 10 reviewed contributions give an overview about current research directions in correctness of model-based software compositions. Results from the discussions during the workshop may be found in the ECOOP 2003 workshop reader to be published by Springer LNCS. The web page of the workshop as well as the contributions of this proceedings may be found at URL: http://ssel.vub.ac.be/workshops/ECOOP2003/ Affiliated to previous ECOOP conferences a related workshop about feature interaction (ECOOP 2001) and an additional about model-based software reuse (ECOOP 2002) have been held. Their contributions are published as technical report No. 2001-14 and as technical report No. 2002-4, respectively, at the Universitaet Karlsruhe, Fakultaet fuer Informatik. URLs: http://www.info.uni-karlsruhe.de/~pulvermu/workshops/ecoop2001/ http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=/ira/2001/14 http://www.info.uni-karlsruhe.de/~pulvermu/workshops/ECOOP2002/ http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=/ira/2002/4 We would like to thank the program committee for their support as well as the authors and participants for their engaged contributions. The Workshop Organisers Ragnhild Van Der Straeten, Andreas Speck, Elke Pulvermueller, Matthias Clauss, Andreas Pleus

Combining SOA and BPM Technologies for Cross-System Process Automation

This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation

Developing sustainable business models for institutions’ provision of open educational resources: Learning from OpenLearn users’ motivations and experiences

Universities across the globe have, for some time, been exploring the possibilities for achieving public benefit and generating business and visibility through releasing and sharing open educational resources (OER). Many have written about the need to develop sustainable and profitable business models around the production and release of OER. Downes (2006), for example, has questioned the financial sustainability of OER production at scale. Many of the proposed business models focus on OER’s value in generating revenue and detractors of OER have questioned whether they are in competition with formal education. This paper reports on a study intended to broaden the conversation about OER business models to consider the motivations and experiences of OER users as the basis for making a better informed decision about whether OER and formal learning are competitive or complementary with each other. The study focused on OpenLearn - the Open University’s (OU) web-based platform for OER, which hosts hundreds of online courses and videos and is accessed by over 3,000,000 users a year. A large scale survey and follow-up interviews with OpenLearn users worldwide revealed that university provided OER can offer learners a bridge to formal education, allowing them to try out a subject before registering on a formal course and to build confidence in their abilities as learners. In addition, it was found that using OER during formal paid-for study can improve learners’ performance and self-reliance, leading to increased retention and satisfaction with the learning experience

GPU Accelerated Approach to Numerical Linear Algebra and Matrix Analysis with CFD Applications

A GPU accelerated approach to numerical linear algebra and matrix analysis with CFD applications is presented. The works objectives are to (1) develop stable and efficient algorithms utilizing multiple NVIDIA GPUs with CUDA to accelerate common matrix computations, (2) optimize these algorithms through CPU/GPU memory allocation, GPU kernel development, CPU/GPU communication, data transfer and bandwidth control to (3) develop parallel CFD applications for Navier Stokes and Lattice Boltzmann analysis methods. Special consideration will be given to performing the linear algebra algorithms under certain matrix types (banded, dense, diagonal, sparse, symmetric and triangular). Benchmarks are performed for all analyses with baseline CPU times being determined to find speed-up factors and measure computational capability of the GPU accelerated algorithms. The GPU implemented algorithms used in this work along with the optimization techniques performed are measured against preexisting work and test matrices available in the NIST Matrix Market. CFD analysis looked to strengthen the assessment of this work by providing a direct engineering application to analysis that would benefit from matrix optimization techniques and accelerated algorithms. Overall, this work desired to develop optimization for selected linear algebra and matrix computations performed with modern GPU architectures and CUDA developer which were applied directly to mathematical and engineering applications through CFD analysis

Open educational resources for all? Comparing user motivations and characteristics across The Open University’s iTunes U channel and OpenLearn platform.

With the rise in access to mobile multimedia devices, educational institutions have exploited the iTunes U platform as an additional channel to provide free educational resources with the aim of profile-raising and breaking down barriers to education. For those prepared to invest in content preparation, it is possible to produce interactive, portable material that can be made available globally. Commentators have questioned both the financial implications for platform-specific content production, and the availability of devices for learners to access it (Osborne, 2012). The Open University (OU) makes its free educational resources available on iTunes U and via its web-based open educational resources (OER) platform, OpenLearn. The OU’s OER on iTunes U reached the 60 million download mark in 2013; its OpenLearn platform boasts 27 million unique visitors since 2006. This paper reports the results of a large-scale study of users of the OU’s iTunes U channel and OpenLearn platform. A survey of several thousand users revealed key differences in demographics between those accessing OER via the web and via iTunes U. In addition, the data allowed comparison between three groups: formal learners, informal learners and educators. The study raises questions about whether university-provided OER meet the needs of users and makes recommendations for how content can be modified to suit their needs. As the publishing of OER becomes core to business, we reflect on reasons why understanding users’ motivations and demographics is vital, allowing for needs-led resource provision and content that is adapted to best achieve learner satisfaction, and to deliver institutions’ social mission