| 1. |
- Zhang, S. N., et al.
(författare)
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The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 9780819496126
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Konferensbidrag (refereegranskat)abstract
- The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO.
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| 2. |
- Zhang, S. -N, et al.
(författare)
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Introduction to the high energy cosmic-radiation detection (HERD) facility onboard China's future space station
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads onboard China's Space Station, which is planned for operation starting around 2025 for about 10 years. The main scientific objectives of HERD are searching for signals of dark matter annihilation products, precise cosmic electron (plus positron) spectrum and anisotropy measurements up to 10 TeV, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 7,500 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of six X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side STKs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV and 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R&D is under way for reading out the LYSO signals with optical fiber coupled to image intensified IsCMOS and CALO prototype of 250 LYSO crystals.
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| 3. |
- Kristan, M., et al.
(författare)
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The Eighth Visual Object Tracking VOT2020 Challenge Results
- 2020
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Ingår i: Computer Vision. - Cham : Springer International Publishing. - 9783030682378 ; , s. 547-601
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2020 is the eighth annual tracker benchmarking activity organized by the VOT initiative. Results of 58 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The VOT2020 challenge was composed of five sub-challenges focusing on different tracking domains: (i) VOT-ST2020 challenge focused on short-term tracking in RGB, (ii) VOT-RT2020 challenge focused on “real-time” short-term tracking in RGB, (iii) VOT-LT2020 focused on long-term tracking namely coping with target disappearance and reappearance, (iv) VOT-RGBT2020 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2020 challenge focused on long-term tracking in RGB and depth imagery. Only the VOT-ST2020 datasets were refreshed. A significant novelty is introduction of a new VOT short-term tracking evaluation methodology, and introduction of segmentation ground truth in the VOT-ST2020 challenge – bounding boxes will no longer be used in the VOT-ST challenges. A new VOT Python toolkit that implements all these novelites was introduced. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website (http://votchallenge.net ).
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| 4. |
- Tommasini, R., et al.
(författare)
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Accepted Tutorials at The Web Conference 2022
- 2022
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Ingår i: WWW 2022 - Companion Proceedings of the Web Conference 2022. - New York, NY, USA : Association for Computing Machinery (ACM). ; , s. 391-399
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Konferensbidrag (refereegranskat)abstract
- This paper summarizes the content of the 20 tutorials that have been given at The Web Conference 2022: 85% of these tutorials are lecture style, and 15% of these are hands on.
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| 5. |
- Abgrall, N., et al.
(författare)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Konferensbidrag (refereegranskat)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 6. |
- Andersson, V., et al.
(författare)
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Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)
- 2005
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Ingår i: Proceedings of the 22nd Texas Symposium on Relativistic Astrophysics at Stanford. ; , s. 736-743
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Konferensbidrag (refereegranskat)abstract
- We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10 % polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view (~ 5 deg2) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected.
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| 7. |
- Chen, X., et al.
(författare)
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Achieving memory access equalization via round-trip routing latency prediction in 3D many-core NoCs
- 2015
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Ingår i: Proceedings of IEEE Computer Society Annual Symposium on VLSI, ISVLSI. - : IEEE. ; , s. 398-403
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Konferensbidrag (refereegranskat)abstract
- 3D many-core NoCs are emerging architectures for future high-performance single chips due to its integration of many processor cores and memories by stacking multiple layers. In such architecture, because processor cores and memories reside in different locations (center, corner, edge, etc.), memory accesses behave differently due to their different communication distances, and the performance (latency) gap of different memory accesses becomes larger as the network size is scaled up. This phenomenon may lead to very high latencies suffered from by some memory accesses, thus degrading the system performance. To achieve high performance, it is crucial to reduce the number of memory accesses with very high latencies. However, this should be done with care since shortening the latency of one memory access can worsen the latency of another as a result of shared network resources. Therefore, the goal should focus on narrowing the latency difference of memory accesses. In the paper, we address the goal by proposing to prioritize the memory access packets based on predicting the round-trip routing latencies of memory accesses. The communication distance and the number of the occupied items in the buffers in the remaining routing path are used to predict the round-trip latency of a memory access. The predicted round-trip routing latency is used as the base to arbitrate the memory access packets so that the memory access with potential high latency can be transferred as early and fast as possible, thus equalizing the memory access latencies as much as possible. Experiments with varied network sizes and packet injection rates prove that our approach can achieve the goal of memory access equalization and outperforms the classic round-robin arbitration in terms of maximum latency, average latency, and LSD1. In the experiments, the maximum improvement of the maximum latency, the average latency and the LSD are 80%, 14%, and 45% respectively.
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| 8. |
- Cui, Z. H., et al.
(författare)
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Twin-Load: Bridging the Gap between Conventional Direct-Attached and Buffer-on-Board Memory Systems
- 2016
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Ingår i: Memsys 2016: Proceedings of the International Symposium on Memory Systems. - New York, NY, USA : ACM. - 9781450343053 ; 03-06-October-2016, s. 164-176
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Konferensbidrag (refereegranskat)abstract
- Conventional systems with direct-attached DRAM struggle to meet growing memory capacity demands: the number of channels is limited by pin count, and the number of modules per channel is limited by signal integrity issues. Recent buffer-on-board (BOB) designs move some memory controller functionality to a separate buff er chip, which lets them support larger capacities (by adding more DRAM or denser, non-volatile components). Nonetheless, lower-cost, lower-latency, direct-attached DRAM still represents a better price-performance solution for many applications. Most processors exclusively implement either the direct-attached or the BOB approach. Combining both technologies within one processor has obvious bene fits, but current memory-interface requirements complicate this straightforward solution. The standard DRAM interface is DDR, which requires data to be returned at a fixed latency. In contrast, the BOB interface supports diverse memory technologies precisely because it allows asynchrony. We propose Twin-Load technology to enable one processor to support both direct-attached and BOB memory. We show how to use Twin-Load to support BOB memory over standard DDR interfaces with minimal processor modifications. We build an asynchronous protocol over the existing, synchronous interface by splitting each memory read into twinned loads. The first acts as a prefetch to the buffer chip, and the second asynchronously fetches the data. We describe three methods for generating twinned loads, each leveraging different layers of the system stack.
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| 9. |
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| 10. |
- Chen, Q, et al.
(författare)
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Photoluminescence from tensile-strained Ge quantum dots
- 2016
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Ingår i: The 2016 IEEE Summer Topical Meeting Series, SUM 2016, Newport Beach, USA, July 11th-13th, 2016. - 9781509019007 ; , s. 120-121
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Konferensbidrag (refereegranskat)abstract
- It has been theoretically predicted that 1.9% biaxial tensile strain can convert Ge [1], which is compatible with Si CMOS technology, into a direct band-gap semiconductor, making it a candidate material for light sources on Si [2, 3]. Combining the advantage of tensile strain with quantum dot (QD), we proposed that tensile-strained QD is a new route toward light emission from Ge [4]. In this work, we chose In0.52Al0.48As, which is lattice matched to InP, as barrier layer and grew the structure by molecular beam epitaxy (MBE). Photoluminescence (PL) was successfully achieved at room temperature.
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