329 research outputs found

    Comparative hierophany at three object scales

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    There was once a village, and close by it there was a waterfall. Villagers believed that under the waterfall there lived a stone golem. This golem was thought to be largely good-natured, as it wouldn\u27t mind people bathing in the pool downstream. Old people remembered that once the golem saved a drowning child by putting a rock under its feet. Many years passed, and the Bureau of Tourism and Recreation briefly considered using this story in its advertising materials for the region. Senior management rejected the idea, as it was thought to contain folklore elements that may be confusing to a global audience

    Finding Best Compiler Options for Critical Software Using Parallel Algorithms

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    The efficiency of a software piece is a key factor for many systems. Real-time programs, critical software, device drivers, kernel OS functions and many other software pieces which are executed thousands or even millions of times per day require a very efficient execution. How this software is built can significantly affect the run time for these programs, since the context is that of compile-once/run-many. In this sense, the optimization flags used during the compilation time are a crucial element for this goal and they could make a big difference in the final execution time. In this paper, we use parallel metaheuristic techniques to automatically decide which optimization flags should be activated during the compilation on a set of benchmarking programs. The using the appropriate flag configuration is a complex combinatorial problem, but our approach is able to adapt the flag tuning to the characteristics of the software, improving the final run times with respect to other spread practicesThis research has been partially funded by the Spanish MINECO and FEDER projects (TIN2014-57341-R (http://moveon.lcc.uma.es), TIN2016-81766-REDT (http://cirti.es), and TIN2017-88213-R (http://6city.lcc.uma.es). It is also funded by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Network-aware design-space exploration of a power-efficient embedded application

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    The paper presents the design and multi-parameter optimization of a networked embedded application for the health-care domain. Several hardware, software, and application parameters, such as clock frequency, sensor sampling rate, data packet rate, are tuned at design- and run-time according to application specifications and operating conditions to optimize hardware requirements, packet loss, power consumption. Experimental results show that further power efficiency can be achieved by considering also communication aspects during design space exploratio

    Makerspaces and the remaking of higher education

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    Onset of Wave Drag due to Generation of Capillary-Gravity Waves by a Moving Object as a Critical Phenomenon

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    The onset of the {\em wave resistance}, via generation of capillary gravity waves, of a small object moving with velocity VV, is investigated experimentally. Due to the existence of a minimum phase velocity VcV_c for surface waves, the problem is similar to the generation of rotons in superfluid helium near their minimum. In both cases waves or rotons are produced at V>VcV>V_c due to {\em Cherenkov radiation}. We find that the transition to the wave drag state is continuous: in the vicinity of the bifurcation the wave resistance force is proportional to VVc\sqrt{V-V_c} for various fluids.Comment: 4 pages, 7 figure

    Software performance estimation strategies in a system-level design tool

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    High-level cost and performance estimation, coupled with a fast hardware/software co-simulation framework, is a key enabler to a fast embedded system design cycle. Unfortunately, the problem of deriving such estimates without a detailed implementation available is difficult.In this paper we describe two approaches to solve software cost and performance estimation problem, and how they are used in an embedded system design environment. A source-based approach uses compilation onto a virtual instruction set, and allows one to quickly obtain estimates without the need for a compiler for the target processor. An object-based approach translates the assembler generated by the target compiler to “assembler-level,” functionally equivalent t C. In both cases the code is annotated with timing and other execution related information (e.g., estimated memory accesses) and is used as a precise, yet fast, software simulation model. We contrast the precision and speed of these two techniques comparing them with those obtainable by a state-of-the-art cycle-based processor model

    Preparation of Cu(In,Ga)Se2 photovoltaic absorbers by an aqueous metal selenite co-precipitation route

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    In this paper, we report a novel and simple solution-based approach for the fabrication of chalcopyrite Cu(In,Ga)Se2 thin film solar cells. An aqueous co-precipitation method based on metal selenites, M2(SeO3)x (M = Cu, In, Ga) precursors was investigated. The resulting powder, dispersed in a binder to form an ink, was coated on a substrate by doctor blade technique. A soft annealing treatment allowed the reduction of metal selenites into selenides. Further rapid thermal processing (RTP) achieved crystalline chalcopyrite absorber. The obtained layer provides good compositional control and adequate morphology for solar cell applications. The water-based synthesis is a sustainable and simple procedure, and together with doctor blade printing, provides a potential cost-effective advantage over conventional fabrication processes (vacuum-based deposition techniques). The short circuit current (JSC), open circuit voltage (VOC), fill factor (FF), and total area power conversion efficiency (Eff.) of the device are 26 mA/cm2, 450 mV, 62%, and 7.2%, respectively. The effective band gap of 1.12 eV confirmed Ga-incorporation in the CIGS crystal lattice.This work was supported by the Spanish Ministry of Science and Competiveness under INNPACTO Program (IPT-2011-0913- 920000). The authors would like to thanks to Manuel Ocana Jurado ~ (ICMS-CISC) for his help in the XPS measurements. L. Oliveira would like to thank the support of the National Council for Scientific and Technological Development (CNPq) e Brazil
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