| 1. |
- Zhang, S. -N, et al.
(author)
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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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In: Proceedings of Science. - : Sissa Medialab Srl.
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Conference paper (peer-reviewed)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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| 2. |
- Asano, H., et al.
(author)
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Spectroscopic study of the Λ(1405) resonance via the d (K-, n) reaction at J-PARC
- 2019
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In: 13th International Conference on Hypernuclear and Strange Particle Physics, HYP 2018. - : AIP Publishing. - 9780735418721 ; 2130
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Conference paper (peer-reviewed)abstract
- The structure of the Λ(1405) hyperon is an important and long-standing issue related to the K̄-nucleus interaction. The J-PARC E31 experiment has been performed to investigate the Λ(1405) spectrum shape. Because it is hard to form the Λ(1405) directly by a K̄N scattering in free space, E31 uses the d(K-, n) reaction with an incident kaon momentum of 1 GeV/c. We will identify three final states - ς-π+, ς+π-, ς0π0-so that the isospin structure of hyperon resonance states produced can be decomposed. The first physics run of the E31 experiment was performed in 2016. To enhance the statistics of the data set, we have performed the second physics run in the beginning of 2018. During the second run of E31, around 3.9×1010 kaons impacted on the deuteron target.
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| 3. |
- Kristan, Matej, et al.
(author)
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The Visual Object Tracking VOT2016 Challenge Results
- 2016
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In: COMPUTER VISION - ECCV 2016 WORKSHOPS, PT II. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 777-823
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Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2016 aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 70 trackers are presented, with a large number of trackers being published at major computer vision conferences and journals in the recent years. The number of tested state-of-the-art trackers makes the VOT 2016 the largest and most challenging benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the Appendix. The VOT2016 goes beyond its predecessors by (i) introducing a new semi-automatic ground truth bounding box annotation methodology and (ii) extending the evaluation system with the no-reset experiment.
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| 4. |
- Yamaga, Takumi, et al.
(author)
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Study of the elementary (K -, n) reactions to search for the K NN bound state via the 3He (K -, n) reaction at J-PARC
- 2016
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In: XVIth International Conference on Hadron Spectroscopy, Hadron 2015. - : Author(s). - 9780735413894 ; 1735
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Conference paper (peer-reviewed)abstract
- We have searched for the simplest kaonic nuclear state, K̄NN, using the in-flight 3He (K-, n) reaction at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at θnlab=0°, an excess of yield was observed just below the K- pp mass-threshold, which cannot be explained by any elementary reactions [PTEP 2015, 061D01]. To understand the missing-mass spectrum of 3He (K-, n) X, we investigated the elementary (K-, n) reactions using hydrogen and deuterium targets. The p (K-, n) X missing-mass spectrum was well described by the charge-exchange reaction. However, in the d (K-, n) X spectrum, we observed an excess of yield just below the K- p mass-threshold, which was similar to that in the 3He (K-, n) X spectrum.
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| 5. |
- Cardenas, J. F., et al.
(author)
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Structure and Mesoscopic Characterization of Laser Ablated Carbon Nanoparticles in Water by Raman Scattering
- 2016
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In: Optical Micro- And Nanometrology VI. - : SPIE. - 9781510601352
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Conference paper (peer-reviewed)abstract
- Carbon nanoparticles (CNPs) have been synthesized by laser ablation of polycrystalline graphite in water using a pulsed Nd:YAG laser (1064 nm) with a width of 8 ns and characterized by Raman spectroscopy and atomic force microscopy. The characteristic sizes of CNPs in the supernantant are in the range of 1-2 nm and 10-50 nm with structures corresponding to amorphous and sp(2)-carbon, respectively. Raman spectra of the CNPs from the supernatant reveal a background as a consequence of photoluminescence. The absence of a distinct Raman peak associated with hydrogenated amorphous carbon (a-C:H) suggests an other source for the photolominescence than a-C:H. Large (10-100 mu m) CNPs removed from the surface are unmodified (in structure and topology) by the laser as confirmed by Raman analysis.
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| 6. |
- Huang, S. -C, et al.
(author)
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Design, optimization and fabrication of two-dimension high contrast subwavelength grating (HCG) mirror on Silicon-on-insulator
- 2015
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In: 4th International Symposium on Next-Generation Electronics, IEEE ISNE 2015. - : IEEE conference proceedings. - 9781479942084
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Conference paper (peer-reviewed)abstract
- The high contrast grating (HCG) mirror has been illustrated and characterized. The investigated parameters including grating periods and filling factors were calculated by finite-difference time-domain method. The two-dimension HCG was fabricated by electron-beam lithography and inductively coupled plasma process. The reflectivity of the fabricated HCG mirror was measured, resulting in around 200 nm bandwidth. The measured result also showed a good agreement with calculated one. This achievement was promising in developing the novel light emitters in the telecommunication region.
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| 7. |
- Kong, C., et al.
(author)
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Effect of channel aging on the sum rate of uplink massive MIMO systems
- 2015
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In: IEEE International Symposium on Information Theory - Proceedings. - 2157-8095. - 9781467377041 ; , s. 1222-1226
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Conference paper (peer-reviewed)abstract
- This paper investigates the achievable sum-rate of uplink massive multiple-input multiple-output (MIMO) systems considering a practical channel impairment, namely, aged channel state information (CSI). Taking into account both maximum ratio combining (MRC) and zero-forcing (ZF) receivers at the base station, we present tight closed-form lower bounds on the sum-rate for both receivers, which provide efficient means to evaluate the sum-rate of the system. More importantly, we characterize the impact of channel aging on the power scaling law. Specifically, we show that the transmit power of each user can be scaled down by 1/√M, which indicates that aged CSI does not affect the power scaling law; instead, it causes only a reduction on the sum rate by reducing the effective signal-to-interference-and-noise ratio (SINR).
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| 8. |
- Kong, C., et al.
(author)
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Performance of downlink massive MIMO in ricean fading channels with ZF precoder
- 2015
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In: IEEE International Conference on Communications. - 1550-3607. - 9781467364324 ; , s. 1776-1782
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Conference paper (peer-reviewed)abstract
- We investigate the achievable sum rate and energy efficiency of zero-forcing precoded downlink massive multipleinput multiple-output systems in Ricean fading channels. A simple and accurate approximation of the average sum rate is presented, which is valid for a system with arbitrary rank channel means. Based on this expression, the optimal power allocation strategy maximizing the average sum rate is derived. Moreover, considering a general power consumption model, the energy efficiency of the system with rank-1 channel means is characterized. Specifically, the impact of key system parameters, such as the number of users N, the number of BS antennas M, Ricean factor K and the signal-to-noise ratio (SNR) ρ are studied, and closed-form expressions for the optimal ρ and M maximizing the energy efficiency are derived. Our findings show that the optimal power allocation scheme follows the water filling principle, and it can substantially enhance the average sum rate in the presence of strong line-of-sight effect in the low SNR regime. In addition, we demonstrate that the Ricean factor K has significant impact on the optimal values of M, N and ρ.
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| 9. |
- Osorio, C., et al.
(author)
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A Metamodel Simulation-based Optimization Approach for the Efficient Calibration of Stochastic Traffic Simulators
- 2015
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In: Transportation Research Procedia. - : Elsevier. - 2352-1465.
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Conference paper (peer-reviewed)abstract
- This work considers the calibration of stochastic microscopic traffic simulators. It formulates the calibration problem as a simulation-based optimization (SO) problem, and uses metamodel SO ideas. The main idea is to embed within the calibration algorithm an analytical problem-specific description of how the calibration parameters are related to the simulation-based objective function. Preliminary results on a toy network are presented. Ongoing work applies these ideas to the calibration of a Berlin metropolitan area network.
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| 10. |
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