Brook GLES Pi: democratising accelerator programming

Nowadays computing is heavily-based on accelerators, however, the cost of the hardware equipment prevents equal access to heterogeneous programming. In this work we present Brook GLES Pi, a port of the accelerator programming language Brook. Our solution, primarily focused on the educational platform Raspberry Pi, allows to teach, experiment and take advantage of heterogeneous programming on any low-cost embedded device featuring an OpenGL ES 2 GPU, democratising access to accelerator programming.This work has been partially supported by the Spanish Ministry of Science and Innovation under grant TIN2015-65316-P and the HiPEAC Network of Excellence.Peer ReviewedPostprint (author's final draft

The U(1)^3 Model of Euclidean Quantum Gravity

Loop quantum gravity is one of the leading candidates to construct a mathematically well-defined, non-perturbative and background independent quantisation of general relativity. In spite of the well developed kinematical structure, loop quantum gravity is plagued by the lack of an unambiguous formulation of its dynamics. This long-standing issue of dynamics is one of the main open problems yet to be addressed. Finding a way to improve the situation requires rumination and a deeper understanding of the problem which can be provided by applying LQG techniques to simpler theories. So far, studying such toy models has given us a new perception of the difficulties and ambiguities of dynamics. The weak coupling limit of Euclidean gravity serves as a toy model which captures the significant structure of GR. It is simply constructed by replacing the constraints of the Ashtekar-Barbero SU(2) gauge theory of Euclidean gravity with their U(1)3 version. In particular, it demonstrates a non-trivial realisation of the hypersurface deformation algebra which proves it can be an interesting testing ground for (Euclidean) quantum gravity. In this thesis, we study different approaches for the quantisation of the U(1)3 model. Since important levels of Dirac quantisation have already been processed and analysed by Varadarajan et al, our key results mainly concern establishing a suitable framework for the other two approaches; i.e. the reduced phase space and path integral quantisations. This is especially attractive because, in the end, one can compare outcomes of different methods of quantisation to gain fascinating insights into the problem of dynamics. More precisely, we show that in suitable gauges, it is feasible to find a closed and explicit formula for the physical Hamiltonian governing dynamics of physical observables. The rather simple expression of the physical Hamiltonian promises that its quantisation may not be as difficult as one expects. It turns out that analysis of the reduced phase space needs the asymptotic behaviours of the canonical variables, we hence investigate in detail the asymptotically flat boundary conditions of the U(1)3 model, leading to welldefined generators for temporal and spatial asymptotic translations. Furthermore, the covariant origin of the U(1)3 model is found which is considered as the main foundation of path integral quantisation

Asymptotically flat boundary conditions for the U(1)3U(1)^3 model for Euclidean Quantum Gravity

A generally covariant $U(1)^3$ gauge theory describing the $G_N \to 0$ limit of Euclidean general relativity is an interesting test laboratory for general relativity, specially because the algebra of the Hamiltonian and diffeomorphism constraints of this limit is isomorphic to the algebra of the corresponding constraints in general relativity. In the present work, we study boundary conditions and asymptotic symmetries of the $U(1)^3$ model and show that while asymptotic spacetime translations admit well-defined generators, boosts and rotations do not. Comparing with Euclidean general relativity, one finds that exactly the non-Abelian part of the $SU(2)$ Gauss constraint which is absent in the $U(1)^3$ model plays a crucial role in obtaining boost and rotation generators.Comment: 11 page

Determinación de sebo bovino en mantequilla utilizando un método integral

The detection of animal fats such as tallow in butter using standard criteria is more difficult than vegetable fats. In order to perform a complete assessment, several methods are likely to be used together. In the experimental design of this research, compositional characteristics such as fatty acids, sterols and triacylglycerols, along with the conventional physicochemical characteristics of butter mixed with different percentages of tallow (0–15% w/w) were evaluated. An increase of less than 5% (w/w) in bovine tallow content in butter physicochemical tests, sterols and fatty acids could not indicate the adulteration level but the ratio of C6+8+10+12/C18 fatty acids, C52/C50، C52/C48, C52/C46 triacylglycerols, S1, S3, S5-value equation and C52 triacylglycerols could show this adulteration level in butter. Also, the successive use of fatty acids and triacylglycerols resulted in the capability to determine adulteration in butter including bovine tallow above 1% (w/w).La detección de grasas animales, como el sebo en mantequilla, utilizando criterios estándares es más difícil que las grasas vegetales y esto probablemente se puede evaluar mediante la recopilación de métodos de evaluación y mediante un enfoque completo. En el diseño experimental de esta investigación, se evaluaron las características composicionales como los ácidos grasos, esteroles y triacilgliceroles junto con los índices fisicoquímicos convencionales, en mantequilla mezclada con un porcentaje diferente de sebo (0–15% p/p). Mediante un aumento de menos del 5% (p/p) de contenido de sebo bovino en mantequilla, las pruebas fisicoquímicas, los esteroles y los ácidos grasos no pudieron indicar el nivel de adulteración, pero sí lo hizo la relación de ácidos grasos C6+8+10+12/C18, la relación de triacilgliceroles C52C50; C52/C48; C52/C46; los valores de S1, S3, S5 en la ecuación y los triacilgliceroles C52. Además, el uso sucesivo de ácidos grasos y triacilgliceroles dio como resultado la capacidad de determinar la adulteración en la mantequilla, incluido el sebo bovino por encima del 1% (p/p)

Monoclinic modification of 1,2-bis­(diphenyl­seleno­phosphino­yl)ethane

The complete mol­ecule of the title compound, C26H24P2Se2, is generated by crystallographic 2-fold symmetry, with the rotation axis bisecting the central C—C bond. The dihedral angle between the terminal aromatic rings is 74.1 (1)°

Complexity effective memory access scheduling for many-core accelerator architectures

Modern DRAM systems rely on memory controllers that employ out-of-order scheduling to maximize row access lo-cality and bank-level parallelism, which in turn maximizes DRAM bandwidth. This is especially important in graphics processing unit (GPU) architectures, where the large quan-tity of parallelism places a heavy demand on the memory system. The logic needed for out-of-order scheduling can be expensive in terms of area, especially when compared to an in-order scheduling approach. In this paper, we propose a complexity-effective solution to DRAM request schedul-ing which recovers most of the performance loss incurred by a naive in-order first-in first-out (FIFO) DRAM scheduler compared to an aggressive out-of-order DRAM scheduler. We observe that the memory request stream from individual GPU“shader cores ” tends to have sufficient row access local-ity to maximize DRAM efficiency in most applications with-out significant reordering. However, the interconnection net-work across which memory requests are sent from the shader cores to the DRAM controller tends to finely interleave the numerous memory request streams in a way that destroys the row access locality of the resultant stream seen at the DRAM controller. To address this, we employ an intercon-nection network arbitration scheme that preserves the row access locality of individual memory request streams and, in doing so, achieves DRAM efficiency and system perfor-mance close to that achievable by using out-of-order mem-ory request scheduling while doing so with a simpler de-sign. We evaluate our interconnection network arbitration scheme using crossbar, mesh, and ring networks for a base-line architecture of 8 memory channels, each controlled by its own DRAM controller and 28 shader cores (224 ALUs), supporting up to 1,792 in-flight memory requests. Our re-sults show that our interconnect arbitration scheme coupled with a banked FIFO in-order scheduler obtains up to 91% of the performance obtainable with an out-of-order memory scheduler for a crossbar network with eight-entry DRAM controller queues

Extended tabu search-based scheduling to improve profitability in heterogeneous parallel systems

Higher utilization of existing resources and facilities in order to increase efficiency and profitability is always one of the basic challenges for parallel processing systems and environments, and this challenge becomes more complicated when the system resources are heterogeneous. One way to achieve high efficiency and profitability of heterogeneous parallel systems is to schedule tasks optimally. In this paper, an extended tabu search-based scheduling algorithm (ESTS) is presented to improve the profitability of heterogeneous parallel systems, which can achieve suitable solutions in a short computational time. To evaluate the efficiency of the proposed solution, due to the lack of a suitable criterion to evaluate this problem, the obtained results are compared with both the results of an extended scheduling based on a genetic algorithm (ESGA) with a large number of chromosomes and a high number of generations, as well as an extended scheduling based on a simulated annealing algorithm (ESSA) with a linear temperature reduction. The benchmark files of different sizes were tested under the same conditions, and the comparison of results shows the superiority of the proposed solution in terms of profitability and computational time

Production of Arachidonic Acid and Eicosapentaenoic Acid by Mortierella alpina CBS 528.72 on Date Waste

Arahidonska (ARA) i eikozapentaenska (EPA) kiselina, koje proizvodi plijesan Mortierella alpina, važne su za zdravlje ljudi. Uvjeti fermentacije mogu utjecati na sastav masnih kiselina u dobivenom ulju. Kao podloga za fermentaciju uglavnom se koristi obnovljivi i jeftini agro-industrijski otpad. Svrha je ovoga rada bila ispitati istodobnu proizvodnju tih dviju kiselina fermentacijom na čvrstoj podlozi s pomoću plijesni Mortierella alpina CBS 528.72. Otpad od datulja odabran je kao izvor ugljika, a sojina sačma kao izvor dušika. Primjenom Plackett-Burmanovog dizajna procijenjen je utjecaj 11 varijabli na proizvodnju ARA i EPA. Analizom dobivenih rezultata utvrđeno je da su glavne varijable, koje bitno utječu na proizvodnju, starost populacije nacijepljene plijesni, te dodatak lanenog ulja i izvora dušika. Te su tri varijable zatim ispitane pomoću centralno složenog dizajna za optimiranje proizvodnje obiju kiselina. Naposljetku, proveden je test radi potvrde predviđenih optimalnih uvjeta pomoću eksperimentalnih rezultata. Pokazalo se da je moguće optimirati proizvodnju ARA i EPA na otpadu od datulja s pomoću plijesni M. alpina CBS 528.72 prilagođavanjem varijabli procesa fermentacije na čvrstoj podlozi.Arachidonic acid (ARA) and eicosapentaenoic acid (EPA) are important for human health and are produced by the fungus Mortierella alpina. Fermentation conditions may affect fatty acid profile of produced oil. Substrates in solid-state fermentation are usually renewable and low-cost agro-industrial waste. The aim of this research is to study simultaneous production of ARA and EPA by M. alpina CBS 528.72 in solid-state fermentation. Date waste and soybean meal served as carbon and nitrogen sources, respectively. Plackett-Burman design was used to evaluate the impact of eleven process variables on ARA and EPA production. Analysis of the results showed that the main variables with significant impact on production include seed age, and supplementation of linseed oil and nitrogen. These three variables were then studied in a central composite design for the optimization of production of both fatty acids. Finally, reconfirmation test was conducted to obtain experimental results from predicted optimum conditions. This report showed that simultaneous optimization of the production of ARA and EPA by M. alpina CBS 528.72 on date waste can be achieved by modification of process variables in solid-state fermentation