| 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. |
- 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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| 4. |
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| 5. |
- 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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| 6. |
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| 7. |
- Zhang, Y., et al.
(författare)
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A feasibility study on application of redundancy sensors estimation technique to nuclear power plants
- 2019
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Ingår i: International Conference on Nuclear Engineering, Proceedings, ICONE. - : ASME Press. - 9784888983051
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Konferensbidrag (refereegranskat)abstract
- Traditional periodic maintenance techniques being employed in nuclear power plants usually fail to detect the potential degradation in performance of a sensor timely, and may increase workload and radiation exposure of the maintenance staff. The Redundancy Sensors Estimation Technique (RSET) to be presented in this paper is a noninvasive and in-situ monitoring technique based on measurement theory. The technique allows staff to monitor redundant sensors on-line and to assess their performance instantly. If such a REST can be applied to a nuclear power plant, it is expected that it will improve the safety of the plant and reduce the costs of operation and maintenance. This paper is concerned with a feasibility study on the REST's application to a nuclear power plant. The results show that the RSET, featuring a strong generalization ability, can offer state estimation and fault diagnosis to signals from redundant sensors accurately. By adding drift data to the test dataset, the RSET can determine the signal drift accurately. The core algorithm of RSET can be explained by mathematical formulas and has high prediction accuracy. In conclusion, RSET can detect the performance degradation of redundant sensors in advance during the operation of plant.
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| 8. |
- Ansari, Maral, et al.
(författare)
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A Lightweight Metalized-Insert Luneburg Lens
- 2023
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Ingår i: 2023 17TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, EUCAP. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In this paper, a lightweight spherical Luneburg lens with high performance is introduced for use in the frequency range 1 (FR1). The continuously varying refractive index profile of the lens is implemented using a quasi-isotropic partially metalized periodic structure. Much of the lens volume is made of foam, so the design is lightweight, making it applicable for low-band microwave frequency communication systems and, more specifically, 5G communications in FR1. The periodic structure allows a simple and low-cost layered construction with a quasi-isotropic response. This approach improves the scanning performance of the lens in all angular directions when compared to equivalent lens designs previously reported. Such a structure is an ideal candidate for high-gain multi-beam communication systems.
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| 9. |
- Bai, Q., et al.
(författare)
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Experimental investigation on the solidification rate of water in open-cell metal foam with copper fins
- 2018
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Ingår i: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 210-214
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Konferensbidrag (refereegranskat)abstract
- This study focused on the effect of inserting fins into metal foam on the solidification rate. To this aim, a well-designed experimental system with solid-liquid interface visualization was built. Metal foam samples with different fin intervals were prepared for experiments. Solidification process of water saturating in finned metal foam under bottom cooling was experimentally investigated. Results showed that inserting fins into metal foam can make a promotional improvement on solidification rate of water. The solid-liquid interface became curved after inserting fins, compared with metal foam sample without fins. Besides, changing the interval has little effect on the solidification rate.
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| 10. |
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