| 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. |
- Farrell, J. P., et al.
(author)
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Ultrafast X-ray probe of nucleobase photoprotection
- 2012
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In: Quantum Electronics and Laser Science Conference. - 9781467318396 ; , s. 6327153-
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Conference paper (peer-reviewed)abstract
- We will present first results of a UV-pump X-ray-probe study of the photoprotection mechanism of thymine. The experiment used element specific Auger spectroscopy and was carried out at the LCLS.
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| 3. |
- McFarland, B. K., et al.
(author)
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Probing nucleobase photoprotection with soft x-rays
- 2013
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In: XVIIITH INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA. - : EDP Sciences. - 9782759809561 ; , s. 07004-
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Conference paper (peer-reviewed)abstract
- Nucleobases absorb strongly in the ultraviolet region, leading to molecular excitation into reactive states. The molecules avoid the photoreactions by funnelling the electronic energy into less reactive states on an ultrafast timescale via non-Born-Oppenheimer dynamics. Current theory on the nucleobase thymine discusses two conflicting pathways for the photoprotective dynamics. We present our first results of our free electron laser based UV-pump soft x-ray-probe study of the photoprotection mechanism of thymine. We use the high spatial sensitivity of the Auger electrons emitted after the soft x-ray pulse induced core ionization. Our transient spetra show two timescales on the order of 200 fs and 5 ps, in agreement with previous (all UV) ultrafast experiments. The timescales appear at different Auger kinetic energies which will help us to decipher the molecular dynamics.
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| 4. |
- Fang, Cheng, et al.
(author)
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Indoor-indoor and indoor-outdoor propagation trial results at 2.6 GHz
- 2012
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In: Antennas and Propagation Conference (LAPC), 2012 Loughborough. - : IEEE. - 9781467322195 ; , s. 6403064-
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Conference paper (peer-reviewed)abstract
- This paper presents delay spread, coherence bandwidth, and angle-of-arrival statistics derived from an extensive MIMO channel measurement campaign carried out at a central frequency of 2.6GHz. The measurement scenarios include indoor-indoor, indoor-outdoor and indoor-outdoor-indoor. The results are useful for analytical and performance studies of post-3G wireless communication systems such as femtocell design and deployment.
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| 5. |
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| 6. |
- Fedorova, I., et al.
(author)
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On the non-equilibrium segregation of Boron in 9-12%Cr steels
- 2017
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In: 4th International ECCC Creep & Fracture Conference.
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Conference paper (peer-reviewed)abstract
- The addition of only 20-150 ppm of boron to martensitic 9-12%Cr steels has a strong enhancing effect on their creep strength, and boron-added martensitic creep strength enhanced steels have been introduced in power plant constructions. Boron is found to redistribute in the martensitic steels during cooling after normalizing in a non-equilibrium segregation process. In this work we attempt to quantify boron segregation during solution treatment in a martensitic 9%Cr steel containing 108 ppm of boron by atom probe tomography and transmission electron microscopy. The investigated material was a solution treated at 1100C for 1 h and cooled in air. Plate-like boride of Cr2B was found on a prior austenite grain boundary (PAGB). The distribution of B, Cr, Fe, Co, Mo, C and other elements in boride and matrix was quantified. Boron is considered to segregate onto PAGBs by non-equilibrium mechanism.
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| 7. |
- Ghavami, B., et al.
(author)
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Stealthy Attack on Algorithmic-Protected DNNs via Smart Bit Flipping
- 2022
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In: 2022 23rd International Symposium on Quality Electronic Design (ISQED). - : IEEE Computer Society. - 9781665494663
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Conference paper (peer-reviewed)abstract
- Recently, deep neural networks (DNNs) have been deployed in safety-critical systems such as autonomous vehicles and medical devices. Shortly after that, the vulnerability of DNNs were revealed by stealthy adversarial examples where crafted inputs - by adding tiny perturbations to original inputs - can lead a DNN to generate misclassification outputs. To improve the robustness of DNNs, some algorithmic-based countermeasures against adversarial examples have been introduced thereafter.In this paper, we propose a new type of stealthy attack on protected DNNs to circumvent the algorithmic defenses: via smart bit flipping in DNN weights, we can reserve the classification accuracy for clean inputs but misclassify crafted inputs even with algorithmic countermeasures. To fool protected DNNs in a stealthy way, we introduce a novel method to efficiently find their most vulnerable weights and flip those bits in hardware. Experimental results show that we can successfully apply our stealthy attack against state-of-the-art algorithmic-protected DNNs.
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| 8. |
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| 9. |
- Li, G., et al.
(author)
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Driving Maneuvers Analysis Using Naturalistic Highway Driving Data
- 2015
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In: IEEE 18th International Conference on Intelligent Transportation Systems (ITSC), 2015. - 2153-0009. - 9781467365956 ; 2015-October, s. 1761-1766
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Conference paper (peer-reviewed)abstract
- - Accounting about 70% of vehicle miles on roadways, highway driving is a critical issue in traffic safety deployment. Of the various maneuvers that comprise the highly complex driving task, each one requires understanding on the connections between driving states, vehicle performance and drivers' actions. This paper attempts to flesh out a complete picture of driving maneuvers on highways. Eighteen drivers participated in this study. They drove an instrumented vehicle on highways to accumulate 2,600 km naturalistic driving data. The data were segmented and classified into 11 maneuver groups manually. Analysis on the maneuvers revealed that: 1) A maneuver transition probabilities model was proposed. According to this model, 7 typical driving patterns were drawn based on the transition probabilities. Transition events pertaining to approaching/following/lane changing accounted for 95% of all the highway transition events. 2) The durations were 7.6/6.6 s and 7.1/7.0 s for free left/right lane changes and overtake from left/right lane changes, respectively. The numbers were 22.5, 21.4 and 16.3 s for far, middle and near following maneuvers, respectively. Statistical significances were found within both groups. 3) How drivers behave in each maneuver was analyzed. Drivers drove faster in free lane changes than did in overtake lane changes. For overtake lane changes, two driving patterns were observed: accelerate to change lane and decelerate to change lane.
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| 10. |
- Li, G., et al.
(author)
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Lane change maneuver recognition via vehicle state and driver operation signals - Results from naturalistic driving data
- 2015
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In: Proceedings IEEE Intelligent Vehicles Symposium, IV 2015. - 9781467372664 ; 2015-August, s. 865-870
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Conference paper (peer-reviewed)abstract
- - Lane change maneuver recognition is critical in driver characteristics analysis and driver behavior modeling for active safety systems. This paper presents an enhanced classification method to recognize lane change maneuver by using optimized features exclusively extracted from vehicle state and driver operation signals. The sequential forward floating selection (SFFS) algorithm was adopted to select the optimized feature set to maximize the k-nearest-neighbor classifier performance. The hidden Markov models (HMMs), based on the optimized feature set, were developed to classify driver lane change and lane keeping maneuvers. Fifteen drivers participated in the road test for validation with an accumulation of 2,200 km naturalistic driving data, from which 372 lane changes were extracted. Results show that the recognition rate of lane change maneuver achieves 88.2%. The numbers are 87.6% and 88.8% for left and right lane change maneuvers, respectively, superior to the results from conventional classifiers. © 2015 IEEE.
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