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- Jiang, Frank, et al.
(author)
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SVEA : an experimental testbed for evaluating V2X use-cases
- 2022
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In: 2022 IEEE 25TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3484-3489
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Conference paper (peer-reviewed)abstract
- In this paper, we present a hardware and software testbed designed for evaluating vehicle-to-everything (V2X) usecases. From platooning to remote driving, there are many proposals to use V2X communication to solve sustainability or safety issues in transport networks. However, researchers mostly evaluate their proposals in only simulation studies, since setting up real, full-scale field tests can often be prohibitively expensive or time-consuming. The open-sourced Small Vehicles for Autonomy (SVEA) testbed is built around a communication software stack and a 1/10th-scale automated vehicle platform suitable for both cost-effective and time-efficient experimentation with V2X use-cases. The testbed is designed to support evaluation in a wide range of conditions, such as heterogeneous networks or vehicle fleets. To illustrate the suitability of the SVEA testbed for studying V2X use-cases, we detail and implement three use-cases: platooning, adaptive speed regulation from a road-side infrastructure camera, and remote-driving by a human operator sitting in a control tower. Finally, we conclude the paper with a discussion on the use of the platform so far and future development plans.
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| 2. |
- Lockhart, Samuel N, et al.
(author)
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Amyloid and Tau PET Demonstrate Region-Specific Associations in Normal Older People.
- 2017
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In: NeuroImage. - : Elsevier BV. - 1095-9572 .- 1053-8119. ; 150, s. 191-199
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Journal article (peer-reviewed)abstract
- β-amyloid (Aβ) and tau pathology become increasingly prevalent with age, however, the spatial relationship between the two pathologies remains unknown. We examined local (same region) and non-local (different region) associations between these 2 aggregated proteins in 46 normal older adults using [(18)F]AV-1451 (for tau) and [(11)C]PiB (for Aβ) positron emission tomography (PET) and 1.5T magnetic resonance imaging (MRI) images. While local voxelwise analyses showed associations between PiB and AV-1451 tracer largely in the temporal lobes, k-means clustering revealed that some of these associations were driven by regions with low tracer retention. We followed this up with a whole-brain region-by-region (local and non-local) partial correlational analysis. We calculated each participant's mean AV-1451 and PiB uptake values within 87 regions of interest (ROI). Pairwise ROI analysis demonstrated many positive PiB-AV-1451 associations. Importantly, strong positive partial correlations (controlling for age, sex, and global gray matter fraction, p < .01) were identified between PiB in multiple regions of association cortex and AV-1451 in temporal cortical ROIs. There were also less frequent and weaker positive associations of regional PiB with frontoparietal AV-1451 uptake. Particularly in temporal lobe ROIs, AV-1451 uptake was strongly predicted by PiB across multiple ROI locations. These data indicate that Aβ and tau pathology show significant local and non-local regional associations among cognitively normal elderly, with increased PiB uptake throughout the cortex correlating with increased temporal lobe AV-1451 uptake. The spatial relationship between Aβ and tau accumulation does not appear to be specific to Aβ location, suggesting a regional vulnerability of temporal brain regions to tau accumulation regardless of where Aβ accumulates.
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| 6. |
- Provost, Karine, et al.
(författare)
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Comparing ATN-T designation by tau PET visual reads, tau PET quantification, and CSF PTau181 across three cohorts
- 2021
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 48:7, s. 2259-2271
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare rates of tau biomarker positivity (T-status) per the 2018 Alzheimer’s Disease (AD) Research Framework derived from [18F]flortaucipir (FTP) PET visual assessment, FTP quantification, and cerebrospinal fluid (CSF) phosphorylated Tau-181 (PTau181). Methods: We included 351 subjects with varying clinical diagnoses from three cohorts with available FTP PET and CSF PTau181 within 18 months. T-status was derived from (1) FTP visual assessment by two blinded raters; (2) FTP standardized uptake value ratio (SUVR) quantification from a temporal meta-ROI (threshold: SUVR ≥1.27); and (3) Elecsys® Phospho-Tau (181P) CSF (Roche Diagnostics) concentrations (threshold: PTau181 ≥ 24.5 pg/mL). Results: FTP visual reads yielded the highest rates of T+, while T+ by SUVR increased progressively from cognitively normal (CN) through mild cognitive impairment (MCI) and AD dementia. T+ designation by CSF PTau181 was intermediate between FTP visual reads and SUVR values in CN, similar to SUVR in MCI, and lower in AD dementia. Concordance in T-status between modality pairs ranged from 68 to 76% and varied by clinical diagnosis, being highest in patients with AD dementia. In discriminating Aβ + MCI and AD subjects from healthy controls and non-AD participants, FTP visual assessment was most sensitive (0.96) but least specific (0.60). Specificity was highest with FTP SUVR (0.91) with sensitivity of 0.89. Sensitivity (0.73) and specificity (0.72) were balanced for PTau181. Conclusion: The choice of tau biomarker may differ by disease stage and research goals that seek to maximize sensitivity or specificity. Visual interpretations of tau PET enhance sensitivity compared to quantification alone, particularly in early disease stages.
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