| 1. |
- Yabuta, Hikaru, et al.
(författare)
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Macromolecular organic matter in samples of the asteroid (162173) Ryugu
- 2023
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 379:6634
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Tidskriftsartikel (refereegranskat)abstract
- Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by the Hayabusa2 spacecraft. We investigated the macromolecular organic matter in Ryugu samples and found that it contains aromatic and aliphatic carbon, ketone, and carboxyl functional groups. The spectroscopic features of the organic matter are consistent with those in chemically primitive carbonaceous chondrite meteorites that experienced parent-body aqueous alteration (reactions with liquid water). The morphology of the organic carbon includes nanoglobules and diffuse carbon associated with phyllosilicate and carbonate minerals. Deuterium and/or nitrogen-15 enrichments indicate that the organic matter formed in a cold molecular cloud or the presolar nebula. The diversity of the organic matter indicates variable levels of aqueous alteration on Ryugus parent body.
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| 2. |
- Domke, Jens, et al.
(författare)
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At the Locus of Performance: Quantifying the Effects of Copious 3D-Stacked Cache on HPC Workloads
- 2023
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Ingår i: ACM Transactions on Architecture and Code Optimization (TACO). - : Association for Computing Machinery. - 1544-3566 .- 1544-3973. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- Over the last three decades, innovations in the memory subsystem were primarily targeted at overcoming the data movement bottleneck. In this paper, we focus on a specific market trend in memory technology: 3D-stacked memory and caches. We investigate the impact of extending the on-chip memory capabilities in future HPC-focused processors, particularly by 3D-stacked SRAM. First, we propose a method oblivious to the memory subsystem to gauge the upper-bound in performance improvements when data movement costs are eliminated. Then, using the gem5 simulator, we model two variants of a hypothetical LARge Cache processor (LARC), fabricated in 1.5 nm and enriched with high-capacity 3D-stacked cache. With a volume of experiments involving a broad set of proxy-applications and benchmarks, we aim to reveal how HPC CPU performance will evolve, and conclude an average boost of 9.56× for cache-sensitive HPC applications, on a per-chip basis. Additionally, we exhaustively document our methodological exploration to motivate HPC centers to drive their own technological agenda through enhanced co-design.
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| 3. |
- Domke, Jens, et al.
(författare)
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Matrix Engines for High Performance Computing : A Paragon of Performance or Grasping at Straws?
- 2021
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Ingår i: 2021 IEEE 35TH INTERNATIONAL PARALLEL AND DISTRIBUTED PROCESSING SYMPOSIUM (IPDPS). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1056-1065
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Konferensbidrag (refereegranskat)abstract
- Matrix engines or units, in different forms and affinities, are becoming a reality in modern processors; CPUs and otherwise. The current and dominant algorithmic approach to Deep Learning merits the commercial investments in these units, and deduced from the No.1 benchmark in supercomputing, namely High Performance Linpack, one would expect an awakened enthusiasm by the HPC community, too. Hence, our goal is to identify the practical added benefits for HPC and machine learning applications by having access to matrix engines. For this purpose, we perform an in-depth survey of software stacks, proxy applications and benchmarks, and historical batch job records. We provide a cost-benefit analysis of matrix engines, both asymptotically and in conjunction with state-of-the-art processors. While our empirical data will temper the enthusiasm, we also outline opportunities to misuse these dense matrix-multiplication engines if they come for free.
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| 4. |
- Jones, Geraint H., et al.
(författare)
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The Comet Interceptor Mission
- 2024
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Ingår i: Space Science Reviews. - : Springer Nature. - 0038-6308 .- 1572-9672. ; 220:1
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600 ms − 1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
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| 5. |
- Kasaba, Yasumasa, et al.
(författare)
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Mission Data Processor Aboard the BepiColombo Mio Spacecraft : Design and Scientific Operation Concept
- 2020
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 216:3
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Forskningsöversikt (refereegranskat)abstract
- BepiColombo Mio, also known as the Mercury Magnetospheric Orbiter (MMO), is intended to conduct the first detailed study of the magnetic field and environment of the innermost planet, Mercury, alongside the Mercury Planetary Orbiter (MPO). This orbiter has five payload groups; the MaGnetic Field Investigation (MGF), the Mercury Plasma Particle Experiment (MPPE), the Plasma Wave Investigation (PWI), the Mercury Sodium Atmosphere Spectral Imager (MSASI), and the Mercury Dust Monitor (MDM). These payloads operate through the Mission Data Processor (MDP) that acts as an integrated system for Hermean environmental studies by the in situ observation of charged and energetic neutral particles, magnetic and electric fields, plasma waves, dust, and the remote sensing of radio waves and exospheric emissions. The MDP produces three kinds of coordinated data sets: Survey (L) mode for continuous monitoring, Nominal (M) mode for standard analyses of several hours in length (or more), and Burst (H) mode for analysis based on 4-20-min-interval datasets with the highest cadence. To utilize the limited telemetry bandwidth, nominal- and burst-mode data sets are partially downlinked after selections of data based on L- or L/M-mode data, respectively. Burst-mode data can be taken at preset timings, or by onboard automatic triggering. The MDP functions are implemented and tested on the ground as well as cruising spacecraft; they are responsible for conducting full scientific operations aboard spacecraft.
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| 6. |
- Lin, Xue, et al.
(författare)
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Controlled release of matrix metalloproteinase-1 plasmid DNA prevents left ventricular remodeling in chronic myocardial infarction of rats.
- 2009
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Ingår i: Circulation journal : official journal of the Japanese Circulation Society. - 1347-4820. ; 73:12, s. 2315-21
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The present study investigated whether administration of controlled release matrix metalloproteinase-1 (MMP-1) plasmid DNA prevents left ventricular (LV) remodeling in a rat chronic myocardial infarction (MI) model. METHODS AND RESULTS: Rats with a moderate-sized MI were randomized to 2 groups: injection of phosphate buffered saline (PBS) containing microspheres into the peri-infarct area (MI group, n=14) and injection of cationized gelatin microspheres incorporating MMP-1 plasmid DNA (MI+MMP-1 group, 50 microg MMP-1/20 microl; n=14). As a control group (n=14), rats received neither the coronary artery ligation nor the injection of PBS. Echocardiography, cardiac catheterization and histological studies were performed. At 2 and 4 weeks after the treatment, the MI+MMP-1 group had smaller LV end-diastolic and end-systolic dimensions, better fractional area change and smaller akinetic areas than the MI group. The LV end-systolic elastance and time constant of isovolumic relaxation were also better in the MI+MMP-1 group compared with the MI group 4 weeks after the treatment. Fibrosis evaluated with Masson's trichrome staining was less in the MI+MMP-1 group than the MI group. CONCLUSIONS: Gelatin microspheres for the controlled release of MMP-1 plasmid DNA are promising for improving cardiac remodeling and function when they are administered during the chronic phase of MI.
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| 7. |
- Michikami, Tatsuhiro, et al.
(författare)
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Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu
- 2022
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Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 381
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Tidskriftsartikel (refereegranskat)abstract
- Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.
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| 8. |
- Murakami, Go, et al.
(författare)
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Mio - First Comprehensive Exploration of Mercury's Space Environment : Mission Overview
- 2020
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Ingår i: Space Science Reviews. - : Springer Nature. - 0038-6308 .- 1572-9672. ; 216:7
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Forskningsöversikt (refereegranskat)abstract
- Mercury has a unique and complex space environment with its weak global magnetic field, intense solar wind, tenuous exosphere, and magnetospheric plasma particles. This complex system makes Mercury an excellent science target to understand effects of the solar wind to planetary environments. In addition, investigating Mercury's dynamic magnetosphere also plays a key role to understand extreme exoplanetary environment and its habitability conditions against strong stellar winds. BepiColombo, a joint mission to Mercury by the European Space Agency and Japan Aerospace Exploration Agency, will address remaining open questions using two spacecraft, Mio and the Mercury Planetary Orbiter. Mio is a spin-stabilized spacecraft designed to investigate Mercury's space environment, with a powerful suite of plasma instruments, a spectral imager for the exosphere, and a dust monitor. Because of strong constraints on operations during its orbiting phase around Mercury, sophisticated observation and downlink plans are required in order to maximize science outputs. This paper gives an overview of the Mio spacecraft and its mission, operations plan, and data handling and archiving.
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| 9. |
- Podobas, Artur, et al.
(författare)
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A Survey on Coarse-Grained Reconfigurable Architectures From a Performance Perspective
- 2020
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 8, s. 146719-146743
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Tidskriftsartikel (refereegranskat)abstract
- With the end of both Dennard's scaling and Moore's law, computer users and researchers are aggressively exploring alternative forms of computing in order to continue the performance scaling that we have come to enjoy. Among the more salient and practical of the post-Moore alternatives are reconfigurable systems, with Coarse-Grained Reconfigurable Architectures (CGRAs) seemingly capable of striking a balance between performance and programmability. In this paper, we survey the landscape of CGRAs. We summarize nearly three decades of literature on the subject, with a particular focus on the premise behind the different CGRAs and how they have evolved. Next, we compile metrics of available CGRAs and analyze their performance properties in order to understand and discover knowledge gaps and opportunities for future CGRA research specialized towards High-Performance Computing (HPC). We find that there are ample opportunities for future research on CGRAs, in particular with respect to size, functionality, support for parallel programming models, and to evaluate more complex applications.
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| 10. |
- Podobas, Artur, et al.
(författare)
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A template-based framework for exploring coarse-grained reconfigurable architectures
- 2020
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Ingår i: Proceedings 31st IEEE International Conference on Application-Specific Systems, Architectures and Processors (ASAP). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- Coarse-Grained Reconfigurable Architectures (CGRAs) are being considered as a complementary addition to modern High-Performance Computing (HPC) systems. These reconfigurable devices overcome many of the limitations of the (more popular) FPGA, by providing higher operating frequency, denser compute capacity, and lower power consumption. Today, CGRAs have been used in several embedded applications, including automobile, telecommunication, and mobile systems, but the literature on CGRAs in HPC is sparse and the field full of research opportunities. In this work, we introduce our CGRA simulator infrastructure for use in evaluating future HPC CGRA systems. Our CGRA simulator is built on synthesizable VHDL and is highly parametrizable, including support for connectivity, SIMD, data-type width, and heterogeneity. Unlike other related work, our framework supports co-integration with third-party memory simulators or evaluation of future memory architecture, which is crucial to reason around memory-bound applications. We demonstrate how our framework can be used to explore the performance of multiple different kernels, showing the impact of different configuration and design-space options.
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