Offshore operations are extremely expensive because of the operational environment and the necess... more Offshore operations are extremely expensive because of the operational environment and the necessary infrastructure. In this environment, emphasis is placed on high-efficiency operations based on specially tailored solutions combining available resources with new technologies. This results in a significant impact on operational efficiency by lowering costs and ultimately increasing hydrocarbon production. To introduce greater efficiencies in offshore operations, a horizontal openhole candidate well was selected to be equipped with a permanent completion system that would enable multiple fracturing treatments. Later, it was determined that by using a novel viscoelastic polymer-free surfactant-based fluid, the entire operation could be performed in a single operation, adding additional savings to the process and improving efficiency. Interpreted openhole images and advanced sonic logs were used to determine the optimum completion configuration and to select favorable fracture initiati...
2010 International Conference on Embedded Computer Systems: Architectures, Modeling and Simulation, 2010
Low simulation speeds have a critical impact on the design process by limiting the number of desi... more Low simulation speeds have a critical impact on the design process by limiting the number of design options which can be explored. Sampling is a popular fast simulation technique because it can achieve high simulation speed and high accuracy. However state-ofthe-art sampling techniques either consider warm-up as an orthogonal issue and leave the choice of a warm-up technique to the end user, or require cumbersome simulator modifications from the end user. Since the most userfriendly and efficient warm-up techniques are not easily compatible with the most efficient sampling techniques, the end user is left with a difficult choice, or runs the risk of misusing sampling techniques with poor warmup. Transparent Sampling reconciles sampling and warmup techniques by delivering state-of-the-art accuracy and simulation time, while remaining easily accessible to end users not proficient in, or not willing to delve into, fast simulation issues.
Tidal flats and marshes in intertidal environments and estuaries generally cover large areas. The... more Tidal flats and marshes in intertidal environments and estuaries generally cover large areas. The access to these places is usually complicated. The area suffers cycles of flooding and drying under the influence of the tide, which in conjunction with soft and muddy soils makes every movement very difficult. In particular, in tidal channels mud is softer and, many times, it is impossible to move around these areas. Furthermore, muddy tidal flat creeks are often located far away from conventional vehicle access. Then, to perform a topographic study using traditional methodology is not feasible; therefore, an alternative methodology has been developed to deal with these problems. POTOS is a light metallic frame developed to measure creek topography indirectly with good precision. The tensed frame, up to 12 m long, simply supported and weighting only 40 kg allows making relative height measurements of the surface between the supporting posts. The field methodology is described and some results obtained with the instrument developed are presented. Errors were calculated by comparing measurements obtained with the instrument and those gathered by traditional methodologies. Field results are a series of measurements obtained in Bahía Blanca Estuary tidal flats and marshes at different periods of the year.
Proceedings of the National Academy of Sciences, 2011
In the otherwise highly conserved NMR structures of cellular prion proteins (PrP C ) from differe... more In the otherwise highly conserved NMR structures of cellular prion proteins (PrP C ) from different mammals, species variations in a surface epitope that includes a loop linking a β-strand, β2, with a helix, α2, are associated with NMR manifestations of a dynamic equilibrium between locally different conformations. Here, it is shown that this local dynamic conformational polymorphism in mouse PrP C is eliminated through exchange of Tyr169 by Ala or Gly, but is preserved after exchange of Tyr 169 with Phe. NMR structure determinations of designed variants of mouse PrP(121–231) at 20 °C and of wild-type mPrP(121–231) at 37 °C together with analysis of exchange effects on NMR signals then resulted in the identification of the two limiting structures involved in this local conformational exchange in wild-type mouse PrP C , and showed that the two exchanging structures present characteristically different solvent-exposed epitopes near the β2–α2 loop. The structural data presented in this...
In the past few years, several research works have demonstrated that sampling can drastically spe... more In the past few years, several research works have demonstrated that sampling can drastically speed up architecture simulation, and several of these sampling techniques are already largely used. However, for a sampling technique to be both easily and properly used, i.e., plugged and reliably used into many simulators with little or no effort or knowledge from the user, it must fulfill a number of conditions: it should require no hardware-dependent modification of the functional or timing simulator, it should simultaneously consider warm-up and sampling, while still delivering high speed and accuracy. The motivation for this article is that, with the advent of generic and modular simulation frameworks like ASIM, Sys-temC, LSE, MicroLib or UniSim, there is a need for sampling techniques with the aforementioned properties, i.e., which are almost entirely transparent to the user and simulator agnostic. In this article, we propose a sampling technique focused more on transparency than on speed and accuracy, though the technique delivers almost state-of-the-art performance. Our sampling technique is a hardware-independent and integrated approach to warm-up and sampling; it requires no modification of the functional simulator and solely relies on the performance simulator for warm-up. We make the following contributions: (1) a technique for splitting the execution trace into a potentially very large number of variable-size regions to capture program dynamic control flow, (2) a clustering method capable of efficiently coping with such a large number of regions, (3) a budget-based method for jointly considering warm-up and sampling costs, presenting them as a single parameter to the user, and for distributing the number of simulated instructions between warmup and sampling based on the region partitioning and clustering information. Overall, the method achieves an accuracy/time tradeoff that is close to the best reported results using clustering-based sampling (though usually with perfect or hardware-dependent warm-up), with an average CPI error of 1.68% and an average number of simulated instructions of 288 million instructions over the Spec benchmarks. The technique/tool can be readily applied to a wide range of benchmarks, architectures and simulators, and will be * This article is a modified version of the article originally published at IEEE Micro. In the IEEE Micro version, we compared our clustering technique against the technique used in SimPoint 2.0; in this version, we compare against SimPoint 3.0, where the speed of clustering was largely improved. used as a sampling option of the UniSim modular simulation framework.
Offshore operations are extremely expensive because of the operational environment and the necess... more Offshore operations are extremely expensive because of the operational environment and the necessary infrastructure. In this environment, emphasis is placed on high-efficiency operations based on specially tailored solutions combining available resources with new technologies. This results in a significant impact on operational efficiency by lowering costs and ultimately increasing hydrocarbon production. To introduce greater efficiencies in offshore operations, a horizontal openhole candidate well was selected to be equipped with a permanent completion system that would enable multiple fracturing treatments. Later, it was determined that by using a novel viscoelastic polymer-free surfactant-based fluid, the entire operation could be performed in a single operation, adding additional savings to the process and improving efficiency. Interpreted openhole images and advanced sonic logs were used to determine the optimum completion configuration and to select favorable fracture initiati...
2010 International Conference on Embedded Computer Systems: Architectures, Modeling and Simulation, 2010
Low simulation speeds have a critical impact on the design process by limiting the number of desi... more Low simulation speeds have a critical impact on the design process by limiting the number of design options which can be explored. Sampling is a popular fast simulation technique because it can achieve high simulation speed and high accuracy. However state-ofthe-art sampling techniques either consider warm-up as an orthogonal issue and leave the choice of a warm-up technique to the end user, or require cumbersome simulator modifications from the end user. Since the most userfriendly and efficient warm-up techniques are not easily compatible with the most efficient sampling techniques, the end user is left with a difficult choice, or runs the risk of misusing sampling techniques with poor warmup. Transparent Sampling reconciles sampling and warmup techniques by delivering state-of-the-art accuracy and simulation time, while remaining easily accessible to end users not proficient in, or not willing to delve into, fast simulation issues.
Tidal flats and marshes in intertidal environments and estuaries generally cover large areas. The... more Tidal flats and marshes in intertidal environments and estuaries generally cover large areas. The access to these places is usually complicated. The area suffers cycles of flooding and drying under the influence of the tide, which in conjunction with soft and muddy soils makes every movement very difficult. In particular, in tidal channels mud is softer and, many times, it is impossible to move around these areas. Furthermore, muddy tidal flat creeks are often located far away from conventional vehicle access. Then, to perform a topographic study using traditional methodology is not feasible; therefore, an alternative methodology has been developed to deal with these problems. POTOS is a light metallic frame developed to measure creek topography indirectly with good precision. The tensed frame, up to 12 m long, simply supported and weighting only 40 kg allows making relative height measurements of the surface between the supporting posts. The field methodology is described and some results obtained with the instrument developed are presented. Errors were calculated by comparing measurements obtained with the instrument and those gathered by traditional methodologies. Field results are a series of measurements obtained in Bahía Blanca Estuary tidal flats and marshes at different periods of the year.
Proceedings of the National Academy of Sciences, 2011
In the otherwise highly conserved NMR structures of cellular prion proteins (PrP C ) from differe... more In the otherwise highly conserved NMR structures of cellular prion proteins (PrP C ) from different mammals, species variations in a surface epitope that includes a loop linking a β-strand, β2, with a helix, α2, are associated with NMR manifestations of a dynamic equilibrium between locally different conformations. Here, it is shown that this local dynamic conformational polymorphism in mouse PrP C is eliminated through exchange of Tyr169 by Ala or Gly, but is preserved after exchange of Tyr 169 with Phe. NMR structure determinations of designed variants of mouse PrP(121–231) at 20 °C and of wild-type mPrP(121–231) at 37 °C together with analysis of exchange effects on NMR signals then resulted in the identification of the two limiting structures involved in this local conformational exchange in wild-type mouse PrP C , and showed that the two exchanging structures present characteristically different solvent-exposed epitopes near the β2–α2 loop. The structural data presented in this...
In the past few years, several research works have demonstrated that sampling can drastically spe... more In the past few years, several research works have demonstrated that sampling can drastically speed up architecture simulation, and several of these sampling techniques are already largely used. However, for a sampling technique to be both easily and properly used, i.e., plugged and reliably used into many simulators with little or no effort or knowledge from the user, it must fulfill a number of conditions: it should require no hardware-dependent modification of the functional or timing simulator, it should simultaneously consider warm-up and sampling, while still delivering high speed and accuracy. The motivation for this article is that, with the advent of generic and modular simulation frameworks like ASIM, Sys-temC, LSE, MicroLib or UniSim, there is a need for sampling techniques with the aforementioned properties, i.e., which are almost entirely transparent to the user and simulator agnostic. In this article, we propose a sampling technique focused more on transparency than on speed and accuracy, though the technique delivers almost state-of-the-art performance. Our sampling technique is a hardware-independent and integrated approach to warm-up and sampling; it requires no modification of the functional simulator and solely relies on the performance simulator for warm-up. We make the following contributions: (1) a technique for splitting the execution trace into a potentially very large number of variable-size regions to capture program dynamic control flow, (2) a clustering method capable of efficiently coping with such a large number of regions, (3) a budget-based method for jointly considering warm-up and sampling costs, presenting them as a single parameter to the user, and for distributing the number of simulated instructions between warmup and sampling based on the region partitioning and clustering information. Overall, the method achieves an accuracy/time tradeoff that is close to the best reported results using clustering-based sampling (though usually with perfect or hardware-dependent warm-up), with an average CPI error of 1.68% and an average number of simulated instructions of 288 million instructions over the Spec benchmarks. The technique/tool can be readily applied to a wide range of benchmarks, architectures and simulators, and will be * This article is a modified version of the article originally published at IEEE Micro. In the IEEE Micro version, we compared our clustering technique against the technique used in SimPoint 2.0; in this version, we compare against SimPoint 3.0, where the speed of clustering was largely improved. used as a sampling option of the UniSim modular simulation framework.
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Papers by Daniel Perez