1,226 research outputs found

    Performance Evaulation of ISO C restrict on the Power Architecture

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    The C99 standard for the C programming language introduced the new type qualifier restrict which acts as a hint for the compiler and the programmer that the specified pointer is not aliased by any other pointer if the pointed object can be modified. By using restrict on pointers the compiler may, if implemented and allowed, optimize code even further. This thesis investigates how well the C compilers GCC, Clang and XL C implements optimizations based on restrict on the Power architecture. By running a modified Livermore benchmark consisting of different loops that are suitable for restrict based optimizations we show that all three compilers are capable of doing restrict based optimizations. Furthermore we investigate loops using a pipeline simulator in order to understand the performance characteristics of the optimizations. We show that the performance for each loop vary by compiler, some loops have their running time significantly reduced while others, somewhat surprisingly, actually have their run time increased. Finally we provide some general suggestions for programmers and compiler developers on how to best use restrict

    Design and Development of Products and Services at the Base of the Pyramid: A Review of Issues and Solutions

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    Abstract in UndeterminedThe base of the world income pyramid, generally called the ‘Base of the Pyramid’ (BoP), consists of four billion people with average per day income of less than four dollars. Over the past several years, the design and development of products and services at the BoP (BoP people as producers and consumers as well) has been investigated by several authors from different disciplines. A literature review showed that the issues (i.e. constraints) in designing and developing products and services at the BoP and ingredients of solutions addressing these issues have not been synthesised. Furthermore, quantitative findings on these issues and solution-ingredients are lacking. This paper addresses these gaps by pulling together the issues and solution-ingredients in the BoP from the reviewed literature and comparing these with a large study found in this literature. In addition, through the analysis of the data available in this large study, we extracted some quantitative findings on these issues and solution-ingredients, and identified relationships between them. We have discussed the practical implications of these findings. This study adds to the growing body of literature on the sustainable development at the BoP

    Finite element analysis of transient thermomechanical rolling contact using an efficient arbitrary Lagrangian-Eulerian description

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    A theoretical and computational framework for the analysis of thermomechanically coupled transient rolling contact, based on an arbitrary Lagrangian-Eulerian (ALE) kinematical description, is developed. A finite element formulation featuring 2D cylinder-plate rolling contact is implemented. The implementation features penalty-type contact formulations for mechanical and thermal contact. It is noted that the ALE formulation allows for a simplified time description, a compact computational domain and localized mesh refinement. Numerical simulations considering stationary and transient rolling conditions are presented. Highlighted aspects include the influence of variations in thermal contact conductivity, rolling speed and external mechanical load on the contact interface heat flow. The model is shown to give predictions in qualitative agreement with results in the literature. For the velocity range studied, numerical issues such as spurious numerical dissipation/oscillations in the temperature field are noted to have a prominent influence. These phenomena are addressed using a Streamline-Upwind Petrov-Galerkin stabilization scheme together with a bubble function approach

    Motivation, Peer Learning and Feedback in Flexible Learning

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    Based on material from previous classes, three features were examined 1) the respective roles of student-to-student, teacher-to-student and student-to-teacher feedback, 2) the ways in which students collaborated with each other in a peer-learning mode, and 3) the strategies used to enhance the students’ extrinsic and intrinsic motivation. The purpose was to study and describe how feedback, peer learning and motivation were manifested in two VLE-based courses at our department, in order to learn how they relate to constructive alignment and how they support flexible learning in diverse student groups, and based on that suggest changes to enhance student learning

    Listening to Current Practice: Patient Involvement in the Pharmaceutical Packaging Design Process

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    Multiple functional challenges in the use of pharmaceutical packaging reveal a great need of packaging to be designed inclusively. This study investigates patient involvement in the pharmaceutical packaging design process by analysing interview data from representatives of the pharmaceutical and packaging industry. Four main themes related to patient involvement were uncovered: patient expertise levels, patient involvement modes, factors encouraging patient involvement, and factors discouraging patient involvement. Passive patient involvement modes were found to be dominant due to regulations and a traditional perspective regarding physical testing. However, active patient involvement modes were identified, motivated by empathy and understanding of the lives of patients. The pharmaceutical packaging design process is complex and involves multiple stakeholders. The research findings can inspire more industry practitioners and policymakers to design pharmaceutical packaging that is inclusive and with consideration of a broader spectrum of patients’ needs

    Interdigitating organic bilayers direct the short interlayer spacing in hybrid organic–inorganic layered vanadium oxide nanostructures

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    Layered metal oxides provide a single-step route to sheathed superlattices of atomic layers of a variety of inorganic materials, where the interlayer spacing and overall layered structure forms the most critical feature in the nanomaterials’ growth and application in electronics, health, and energy storage. We use a combination of computer simulations and experiments to describe the atomic-scale structure, dynamics and energetics of alkanethiol-intercalated layered vanadium oxide-based nanostructures. Molecular dynamics (MD) simulations identify the unusual substrate-constrained packing of the alkanethiol surfactant chains along each V2O5 (010) face that combines with extensive interdigitation between chains on opposing faces to maximize three-dimensional packing in the interlayer regions. The findings are supported by high resolution electron microscopy analyses of synthesized alkanethiol-intercalated vanadium oxide nanostructures, and the preference for this new interdigitated model is clarified using a large set of MD simulations. This dependency stresses the importance of organic–inorganic interactions in layered material systems, the control of which is central to technological applications of flexible hybrid nanomaterials

    Critical moisture conditions for fungal decay of modified wood by basidiomycetes as detected by pile tests

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    The aim of cell wall modification is to keep wood moisture content (MC) below favorable conditions for decay organisms. However, thermally modified, furfurylated, and acetylated woods partly show higher MCs than untreated wood in outdoor exposure. The open question is to which extent decay is influenced by the presence of liquid water in cell lumens. The present paper contributes to this topic and reports on physiological threshold values for wood decay fungi with respect to modified wood. In total, 4200 specimens made from acetylated, furfurylated, and thermally modified beech wood (Fagus sylvatica L.) and Scots pine sapwood (sW) (Pinus sylvestris L.) were exposed to Coniophora puteana and Trametes versicolor. Piles consisting of 50 small specimens were incubated above malt agar in Erlenmeyer flasks for 16 weeks. In general, pile upward mass loss (ML) and MC decreased. Threshold values for fungal growth and decay (ML≥2%) were determined. In summary, the minimum MC for fungal decay was slightly below fiber saturation point of the majority of the untreated and differently modified materials. Surprisingly, T. versicolor was able to degrade untreated beech wood at a minimum of 15% MC, and growth was possible at 13% MC. By contrast, untreated pine sW was not decayed by C. puteana at less than 29% MC. © 2016 by De Gruyter 2016

    A reparametrization invariant surface ordering

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    We introduce a notion of a non-Abelian loop gauge field defined on points in loop space. For this purpose we first find an infinite-dimensional tensor product representation of the Lie algebra which is particularly suited for fields on loop space. We define the non-Abelian Wilson surface as a `time' ordered exponential in terms of this loop gauge field and show that it is reparametrization invariant.Comment: 11 pages, clarifications and added ref
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