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Träfflista för sökning "WFRF:(Johansson Roger) ;lar1:(ri)"

Sökning: WFRF:(Johansson Roger) > RISE

  • Resultat 1-10 av 13
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1.
  • Ayatolahi, Fatemeh, 1984, et al. (författare)
  • A study of the impact of single bit-flip and double bit-flip errors on program execution
  • 2013
  • Ingår i: Lect. Notes Comput. Sci.. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783642407925 ; , s. 265-276
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents the results of an extensive experimental study of bit-flip errors in instruction set architecture registers and main memory locations. Comprising more than two million fault injection experiments conducted with thirteen benchmark programs, the study provides insights on whether it is necessary to consider double bit-flip errors in dependability benchmarking experiments. The results show that the proportion of silent data corruptions in the program output, is almost the same for single and double bit errors. In addition, we present detailed statistics about the error sensitivity of different target registers and memory locations, including bit positions within registers and memory words. These show that the error sensitivity varies significantly between different bit positions and registers. An important observation is that injections in certain bit positions always have the same impact regardless of when the error is injected.
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2.
  • Bergvall, Niklas, et al. (författare)
  • Continuous Slurry Hydrocracking of Biobased Fast Pyrolysis Oil
  • 2021
  • Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 35:3, s. 2303-2312
  • Tidskriftsartikel (refereegranskat)abstract
    • Co-refining of fast pyrolysis bio-oil together with fossil oil in existing refinery infrastructure is an attractive and cost-efficient route to conversion of lignocellulosic biomass to transportation fuel. However, due to large differences in properties between the two oils, special notice is needed to reduce process-related issues. Here, fast pyrolysis bio-oil produced from lignocellulosic biomass was co-refined with vacuum gas oil at a 20:80 weight ratio in continuous operation in a pilot-scale slurry hydrocracker in order to investigate the impact of process parameters on product quality and process performance. Mass balances together with product characterization were used to investigate product yields, product composition, and hydrodeoxygenation. Best conversion and hydrodeoxygenation of the fast pyrolysis bio-oil was achieved using an unsupported catalyst loading of 900 ppm Mo with either a low temperature (410 °C) and long residence time (2 h) or higher temperature (435 °C) and shorter residence time (1 h). These settings resulted in about 94% hydrodeoxygenation but also led to highest yield of biogenic carbon to gas phase (40-43 wt %) and lowest yield of biogenic carbon to oil fractions (53-56 wt %) as well as the water fraction (3-5 wt %). Successfully, coke yield remained low at around 0.07-0.10 wt % for all performed runs, which was comparable to the insoluble particle content in the feed due to the presence of particles in the untreated fast pyrolysis bio-oil. Co-processing pyrolysis oil with fossil oil in a slurry hydrocracker seems to be a robust process with regard to coke formation, which should lead to reduced plugging issues compared to fixed bed hydrotreaters. Although this study gives a brief understanding of the effect of process parameters on the processing of fast pyrolysis bio-oil, further research is required to find optimal process parameters and to fully comprehend the possibilities and limitations for production of transportation fuels from fast pyrolysis bio-oil using this technology.
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3.
  • Di Leo, D., et al. (författare)
  • On the impact of hardware faults - An investigation of the relationship between workload inputs and failure mode distributions
  • 2012
  • Ingår i: Lect. Notes Comput. Sci.. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642336775 ; , s. 198-209
  • Konferensbidrag (refereegranskat)abstract
    • Technology scaling of integrated circuits is making transistors increasingly sensitive to process variations, wear-out effects and ionizing particles. This may lead to an increasing rate of transient and intermittent errors in future microprocessors. In order to assess the risk such errors pose to safety critical systems, it is essential to investigate how temporary errors in the instruction set architecture (ISA) registers and main memory locations influence the behaviour of executing programs. To this end, we investigate - by means of extensive fault injection experiments - how such errors affect the execution of four target programs. The paper makes three contributions. First, we investigate how the failure modes of the target programs vary for different input sets. Second, we evaluate the error coverage of a software-implemented hardware fault tolerant technique that relies on triple-time redundant execution, majority voting and forward recovery. Third, we propose an approach based on assembly language metrics which can be used to correlate the dynamic fault-free behaviour of a program with its failure mode distribution obtained by fault injection.
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4.
  • Johansson, Ann-Christine, et al. (författare)
  • Comparison of co-refining of fast pyrolysis oil from Salix via catalytic cracking and hydroprocessing
  • 2023
  • Ingår i: Biomass and Bioenergy. - : Elsevier Ltd. - 0961-9534 .- 1873-2909. ; 172
  • Tidskriftsartikel (refereegranskat)abstract
    • Lignocellulosic biomass from energy crops, i.e., short rotation coppice willows such as Salix spp., can be used as feedstock for production of transportation biofuels. Biomass conversion via fast pyrolysis followed by co-refining with fossil oil in existing refinery infrastructure could enable a fast introduction of large-scale production of biofuels. In this study, Salix was first liquefied using ablative fast pyrolysis in a pilot scale unit. The resulting pyrolysis oil, rich in oxygenates, was thereafter co-refined in 20 wt% ratio with fossil feedstock using two separate technologies, a fluidized catalytic cracking (FCC) laboratory unit and a continuous slurry hydroprocessing pilot plant. In the FCC route, the pyrolysis oil was cracked at 798 K using a commercial FCC catalyst at atmospheric pressure, while in the hydroprocessing route, the oil was processed at 693 K and a hydrogen pressure of 15 MPa in the presence of an unsupported molybdenum sulfide catalyst. Both routes resulted in significant deoxygenation (97 wt% versus 93 wt%). It is feasible to co-refine pyrolysis oil using both methods, the main difference being that the hydroprocessing results in a significantly higher biogenic carbon yield from the pyrolysis oil to liquid and gaseous hydrocarbon products (92 wt%) but would in turn require input of H2. In the cracking route, besides the liquid product, a significant part of the biogenic carbon ends up as gas and as coke on the catalyst. The choice of route depends, among other factors, on the available amount of bio-oil and refining infrastructures. © 2023 The Authors
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5.
  • Johansson, Ann-Christine, et al. (författare)
  • Particle formation during suspension combustion of different biomass powders and their fast pyrolysis bio-oils and biochars
  • 2021
  • Ingår i: Fuel processing technology. - : Elsevier B.V.. - 0378-3820 .- 1873-7188. ; 218
  • Tidskriftsartikel (refereegranskat)abstract
    • The fly ash formation during suspension combustion of five different biomass powders (stem wood, bark, forest residue, willow, and reed canary grass) and the corresponding products from fast pyrolysis (bio-oil and biochar) of the powders was investigated. The fifteen fuels were burned in a drop tube furnace under normal (20 vol-% O2) and oxygen-enriched combustion conditions (40 vol-% and 60 vol-% O2). The trends in the data were used to discuss differences in combustion behavior and devise recommendations for the use of the fuels. There was a general difference in fly ash formation mechanism between the solid fuels (biomass and biochar) and the bio-oil fuels, which was attributed to parts of the ash-forming elements in bio-oil being dissolved in the oil. Oxygen-enrichment did not affect the release of inorganic elements to the gas phase for bio-oil combustion. Since the bio-oils generate lower fly ash during combustion, ~100 times compared to the original biomasses, they should be reserved for combustion technologies demanding fuels with very low ash content, whereas the biochar should be used in large scale combustion facilities with advanced gas cleaning technology operated by teams with experience of handling ash related operational problems. © 2021 The Author(s)
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6.
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7.
  • Pykönen, Maiju, et al. (författare)
  • Influence of surface chemical composition on UV-varnish absorption into permeable pigment-coated paper
  • 2010
  • Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 49:5, s. 2169-2175
  • Tidskriftsartikel (refereegranskat)abstract
    • Fluorocarbon, organosilicon, and hydrocarbon plasma coatings were used to modify the surface permeable pigment-coated paper, and their impact on UV-varnish absorption was investigated. According to mercury porosimetry results, the plasma coatings had no influence on the porous structure of the paper. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) results showed characteristic surface chemical compositions for each plasma coating. The fluorocarbon plasma coating increased the UV-varnish contact angles significantly, whereas the hydrocarbon plasma coating had no clear influence. When the UV varnish was applied with a flexography unit including nip pressure, the role of surface chemical composition seemed to become minimal. The viscosity of the UV varnish was shown to impact the absorption rate with and without external pressure.
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8.
  • Rönnberg Wästljung, Ann-Christin, et al. (författare)
  • Optimized utilization of Salix—Perspectives for the genetic improvement toward sustainable biofuel value chains
  • 2022
  • Ingår i: Global Change Biology Bioenergy. - : John Wiley and Sons Inc. - 1757-1693 .- 1757-1707. ; 14:10, s. 1128-144
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioenergy will be one of the most important renewable energy sources in the conversion from fossil fuels to bio-based products. Short rotation coppice Salix could be a key player in this conversion since Salix has rapid growth, positive energy balance, easy to manage cultivation system with vegetative propagation of plant material and multiple harvests from the same plantation. The aim of the present paper is to provide an overview of the main challenges and key issues in willow genetic improvement toward sustainable biofuel value chains. Primarily based on results from the research project “Optimized Utilization of Salix” (OPTUS), the influence of Salix wood quality on the potential for biofuel use is discussed, followed by issues related to the conversion of Salix biomass into liquid and gaseous transportation fuels. Thereafter, the studies address genotypic influence on soil carbon sequestration in Salix plantations, as well as on soil carbon dynamics and climate change impacts. Finally, the opportunities for plant breeding are discussed using willow as a resource for sustainable biofuel production. Substantial phenotypic and genotypic variation was reported for different wood quality traits important in biological (i.e., enzymatic and anaerobic) and thermochemical conversion processes, which is a prerequisite for plant breeding. Furthermore, different Salix genotypes can affect soil carbon sequestration variably, and life cycle assessment illustrates that these differences can result in different climate mitigation potential depending on genotype. Thus, the potential of Salix plantations for sustainable biomass production and its conversion into biofuels is shown. Large genetic variation in various wood and biomass traits, important for different conversion processes and carbon sequestration, provides opportunities to enhance the sustainability of the production system via plant breeding. This includes new breeding targets in addition to traditional targets for high yield to improve biomass quality and carbon sequestration potential. © 2022 The Authors. 
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9.
  • Sangchoolie, Behrooz, et al. (författare)
  • A Comparison of Inject-on-Read and Inject-on-Write in ISA-Level Fault Injection
  • 2016
  • Ingår i: Proceedings - 2015 11th European Dependable Computing Conference, EDCC 2015. - : Institute of Electrical and Electronics Engineers Inc.. - 9781467392891 ; , s. 178-189, s. 178-189
  • Konferensbidrag (refereegranskat)abstract
    • ISA-level fault injection, i.e. the injection of bit-flip faults in Instruction Set Architecture (ISA) registers and main memory words, is widely used for studying the impact of transient and intermittent hardware faults in computer systems. This paper compares two techniques for ISA-level fault injection: inject-on-read, and inject-on-write. The first technique injects bit-flips in a data-item (the content of a register or memory word) just before the data-item is read by a machine instruction, while the second one injects bit-flips in a data-item just after it has been updated by a machine instruction. In addition, the paper compares two variants of inject-on-read, one where all faults are given the same weight and one where weight factors are used to reflect the time a data-item spends in a register or memory word. The weighted injected-on-read aims to accurately model soft errors that occur when an ionizing particle perturbs a data-item while it resides in an ISA register or a memory word. This is in contrast to inject-on-write, which emulates errors that propagate into an ISA register or a memory word. Our experiments show significant differences in the results obtained with the three techniques.
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10.
  • Sangchoolie, Behrooz, et al. (författare)
  • A study of the impact of bit-flip errors on programs compiled with different optimization levels
  • 2014
  • Ingår i: Proceedings - 2014 10th European Dependable Computing Conference, EDCC 2014. - : IEEE Computer Society. - 9781479938032 ; , s. 146-157
  • Konferensbidrag (refereegranskat)abstract
    • In this paper we study the impact of compiler optimizations on the error sensitivity of twelve benchmark programs. We conducted extensive fault injection experiments where bit-flip errors were injected in instruction set architecture registers and main memory locations. The results show that the percentage of silent data corruptions (SDCs) in the output of the optimized programs is only marginally higher compare to that observed for the non-optimized programs. This suggests that compiler optimizations can be used in safety- and mission-critical systems without increasing the risk that the system produces undetected erroneous outputs. In addition, we investigate to what extent the source code implementation of a program affects the error sensitivity of a program. To this end, we perform experiments with five implementations of a bit count algorithm. In this investigation, we consider the impact of the implementation as well as compiler optimizations. The results of these experiments give valuable insights into how compiler optimizations can be used to reduce error sensitive of registers and main memory sections. They also show how sensitive locations requiring additional protection, e.g., by the use of software-based fault tolerance techniques, can be identified.
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