Lost in translation: Exposing hidden compiler optimization opportunities

Existing iterative compilation and machine-learning-based optimization techniques have been proven very successful in achieving better optimizations than the standard optimization levels of a compiler. However, they were not engineered to support the tuning of a compiler's optimizer as part of the compiler's daily development cycle. In this paper, we first establish the required properties which a technique must exhibit to enable such tuning. We then introduce an enhancement to the classic nightly routine testing of compilers which exhibits all the required properties, and thus, is capable of driving the improvement and tuning of the compiler's common optimizer. This is achieved by leveraging resource usage and compilation information collected while systematically exploiting prefixes of the transformations applied at standard optimization levels. Experimental evaluation using the LLVM v6.0.1 compiler demonstrated that the new approach was able to reveal hidden cross-architecture and architecture-dependent potential optimizations on two popular processors: the Intel i5-6300U and the Arm Cortex-A53-based Broadcom BCM2837 used in the Raspberry Pi 3B+. As a case study, we demonstrate how the insights from our approach enabled us to identify and remove a significant shortcoming of the CFG simplification pass of the LLVM v6.0.1 compiler.Comment: 31 pages, 7 figures, 2 table. arXiv admin note: text overlap with arXiv:1802.0984

Evaluation of the performance of message routing protocols in delay tolerant networks (DTN) in Colombian scenario

Certain vehicles need to send information to their monitoring stations constantly, this information is usually sent by the vehicles, through the cellular network. The use of these wireless networks depends on coverage that it is not usually available in all geographic areas. This is the case of road segments where the coverage of data service of cellular networks is partial or zero, making transmission impossible. A particular case is the roads between the municipality of Juan de Acosta and the city of Barranquilla in Atlántico department (Colombia). As a solution, Delay-Tolerant Networks (DTN) emerge, which allow the transmission of data to the monitoring stations when there is no cellular network coverage. In this work, a simulated evaluation of the performance of some message routing protocols for DTN is performed, in the Juan de Acosta – Barranquilla scenario. Using “The Opportunistic Networking Environment”, we determined the performance of these message routing protocols. The results show that the first contact message routing protocol, presents the highest rate of delivery messages (delivery rate) and the lowest delivery latency (delivery latency). In addition, the Spray and Wait protocol presents better results in System message overload (overhead) than the first one. The Opportunistic Networking Environment simulator, the performance of these message routing protocols was determined in this scenario. The results show that the Firstcontact message routing protocol presents the highest rate of delivery (deliveryrate) and the lowest delivery delay (deliverylatency). In addition, the Spray and Wait protocol has a better result in system overhead than the first one

Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

Design of an automated spray wash system for parts to paint with electrostatic coating in the Company Creacion Pintura y Diseño S.A.S

Creación Pintura y Diseño S.A.S es una empresa dedicada a pintar piezas metálicas, lo cual requiere de procesos que involucran baños químicos a temperaturas y tiempos específicos. Antes de ser impregnadas por pintura en polvo, existe una fase de alistamiento o limpieza, una vez realizado este procedimiento las piezas son impregnadas de pintura en polvo y luego pasan a un horno en el cual se realiza la polimerización. Todos estos procesos se realizan manualmente, y el más crítico es el de alistamiento o lavado, puesto que cuando una pieza queda mal lavada los procesos siguientes se anulan totalmente, por esta razón nuestra propuesta se enfoca en el diseño de un sistema automatizado de lavado para piezas, que sustituiría el primer proceso mejorando la calidad de lavado de las piezas y disminuyendo los tiempos de operación en esta fase. El sistema automatizado de lavado para piezas está compuesto por un sistema de transporte de piezas electromecánico que traslada las piezas por intermedio de cadenas y dispositivos desde el lugar de alimentación pasando por cabinas de lavado hasta las cabinas de pintura, en el lavado se realiza la limpieza de las piezas por aspersión, gracias a una red de tuberías dispuesta en 4 fases; primer pre enjuague, fosfatizado, segundo pre enjuague y pasivado, al finalizar este recorrido las piezas son trasportadas hasta las cabinas de pintura en forma mecánica evitando cualquier tipo de contaminación antes de ser pintadas. El sistema de transporte funciona de manera continua gracias a un circuito de control, dicho circuito también controla el sistema de bombeo y calefacción de los fluidos. Cabe destacar que aparte del lavado de las piezas el sistema también asume el trasporte de las piezas desde la alimentación hasta la pintura, evitando esfuerzos y lesiones innecesarias por parte de los operarios garantizando así un proceso en línea. En el mercado existen sistemas automáticos complejos y costosos que serían inaccesibles a empresas medianas, nuestro diseño menos complejo basado en la reducción de costos es una solución para la empresa Creación Pintura y Diseño S.A.S la cual superaría sus problemas de calidad y producción obteniendo mayor beneficio.Painting and Design Creation S.A.S is a company dedicated to paint metal parts, which requires processes that involve chemical baths at specific temperatures and times. Before being impregnated with powder paint, there is a phase of enlistment or cleaning, once this procedure is performed, the pieces are impregnated with powder paint and then passed to an oven in which the polymerization is carried out. All these processes are carried out manually, and the most critical is the one of enlistment or washing, since when a piece is poorly washed the following processes are completely canceled, for this reason our proposal focuses on the design of an automated washing system for pieces, which would replace the first process, improving the quality of parts washing and decreasing the operation times in this phase. The automated washing system for parts is composed of an electromechanical parts transport system that moves the parts through chains and devices from the feeding place through washing booths to the paint booths, in the washing the cleaning is carried out of the pieces by aspersion, thanks to a network of pipes arranged in 4 phases; first pre-rinse, phosphatized, second pre-rinse and passivated, at the end of this tour the pieces are transported to the paint booths mechanically avoiding any type of contamination before being painted. The transport system works in a continuous way thanks to a control circuit, this circuit also controls the system of pumping and heating of the fluids. It should be noted that apart from the washing of the pieces, the system also assumes the transportation of the pieces from the feeding to the painting, avoiding unnecessary efforts and injuries on the part of the operators, thus guaranteeing an online process. In the market there are complex and expensive automatic systems that would be inaccessible to medium-sized companies, our less complex design based on cost reduction is a solution for the company Pintura Pintura y Diseño S.A.S which would overcome its problems of quality and production obtaining greater benefit

DFT study of hydrogen adsorption on Ni/graphene

DFT calculations with the GGA-PBE exchange correlation functional were used to study H 2 adsorption on a Ni(1 1 1) surface, isolated Ni 13 cluster, and graphene-supported Ni 13 . In comparison with Ni(1 1 1), hydrogen adsorption shows to be more stable on isolated Ni 13 and graphene-supported Ni 13 . In the graphene-supported Ni 13 , pseudo charge density difference calculations showed accumulation of charge density around the Ni-graphene interfacial region. Dissociative H 2 adsorption on Ni(1 1 1) and isolated Ni 13 appears to be a non-activated process, whereas an activation barrier is observed on the graphene-supported Ni 13 . Additionally, the effect of pre-adsorbed hydrogen in H 2 adsorption in the mentioned systems was studied showing that it stabilizes the final state of adsorbed H and decreases the activation barrier.Fil: Amaya Roncancio, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Garcia Blanco, Andres Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Linares, Daniel Humberto. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Física; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin

Incorporation of Co in Different Stages of the Synthesis of Al-PILC and Its Effect as a Fischer–Tropsch Catalyst

Different strategies for incorporating cobalt during the synthesis of an Al-pillared clay material were studied to obtain Co-catalysts to be used as a catalyst in the Fischer–Tropsch reaction to produce synthetic fuels. The catalytic materials were characterized employing N2 adsorption–desorption at 77 K, X-ray diffraction, atomic absorption spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction, and Raman spectroscopy. The catalytic activity of the materials for Fischer–Tropsch synthesis was evaluated at a fixed-bed, laboratory-scale microreactor at 2.0 MPa, and the correlations between the method of synthesis, the properties of the materials, and their catalytic behavior were established.Fil: Amaya, Maria Gabriela. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Garcia Blanco, Andres Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Toncón Leal, Cristian Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin

Confined Iron Nanoparticles on Mesoporous Ordered Silica for Fischer–Tropsch Synthesis

Iron oxide particles were deposited in an ordered mesoporous material (SBA-15) with the aim of studying its behavior in the catalytic hydrogenation of CO (Fischer–Tropsch Synthesis). Bulk iron oxide, and iron supported on porous silica with different textural properties (Aerosil®-200) were used for comparison. The characterization of the materials showed that in the Fe@SBA-15 material, iron nanoparticles were confined inside the mesopores of the SBA-15 support (pore diameter ~ 8 nm), and Fe@Aerosil®-200 material also presented iron oxide nanoparticles highly dispersed on the material. In situ Synchrotron radiation XRD studies were performed in order to study the evolution of iron phases in the Fe@SBA-15 and the bulk iron oxide under hydrogen and hydrogen/carbon monoxide conditions. DFT calculations were performed on bare Fe(100) and a Fe16 cluster in CO activation and CxHy hydrogenation. Catalytic microactivity tests, performed at conversions of ~ 6–8%, showed important differences in the selectivity of the materials. Higher selectivity to methane and light hydrocarbons were observed in the supported catalysts (Fe@SBA-15 and Fe@Aerosil®-200) than in bulk Fe catalyst. Moreover, the supported catalysts showed selectivity to ethylene (Fe@SBA-15) and propylene (Fe@Aerosil®-200), products that were not observed in the bulk iron catalyst. On the other hand, bulk iron showed a major selectivity to higher hydrocarbons (C5–C9) and oxygenates.Fil: Toncón Leal, Cristian Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Amaya Roncancio, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Garcia Blanco, Andres Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Moreno, Mario Sergio Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin