| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 3. |
- Erzurumluoglu, A. Mesut, et al.
(författare)
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Meta-analysis of up to 622,409 individuals identifies 40 novel smoking behaviour associated genetic loci
- 2020
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Ingår i: Molecular Psychiatry. - : Nature Publishing Group. - 1359-4184 .- 1476-5578. ; 25:10, s. 2392-2409
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Tidskriftsartikel (refereegranskat)abstract
- Smoking is a major heritable and modifiable risk factor for many diseases, including cancer, common respiratory disorders and cardiovascular diseases. Fourteen genetic loci have previously been associated with smoking behaviour-related traits. We tested up to 235,116 single nucleotide variants (SNVs) on the exome-array for association with smoking initiation, cigarettes per day, pack-years, and smoking cessation in a fixed effects meta-analysis of up to 61 studies (up to 346,813 participants). In a subset of 112,811 participants, a further one million SNVs were also genotyped and tested for association with the four smoking behaviour traits. SNV-trait associations with P < 5 × 10-8 in either analysis were taken forward for replication in up to 275,596 independent participants from UK Biobank. Lastly, a meta-analysis of the discovery and replication studies was performed. Sixteen SNVs were associated with at least one of the smoking behaviour traits (P < 5 × 10-8) in the discovery samples. Ten novel SNVs, including rs12616219 near TMEM182, were followed-up and five of them (rs462779 in REV3L, rs12780116 in CNNM2, rs1190736 in GPR101, rs11539157 in PJA1, and rs12616219 near TMEM182) replicated at a Bonferroni significance threshold (P < 4.5 × 10-3) with consistent direction of effect. A further 35 SNVs were associated with smoking behaviour traits in the discovery plus replication meta-analysis (up to 622,409 participants) including a rare SNV, rs150493199, in CCDC141 and two low-frequency SNVs in CEP350 and HDGFRP2. Functional follow-up implied that decreased expression of REV3L may lower the probability of smoking initiation. The novel loci will facilitate understanding the genetic aetiology of smoking behaviour and may lead to the identification of potential drug targets for smoking prevention and/or cessation.
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| 4. |
- Abbafati, Cristiana, et al.
(författare)
-
- 2020
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Alanwar, Amr, et al.
(författare)
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Enhancing Data-Driven Reachability Analysis using Temporal Logic Side Information
- 2022
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Ingår i: Proceedings. - : Institute of Electrical and Electronics Engineers Inc..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents algorithms for performingdata-driven reachability analysis under temporal logic sideinformation. In certain scenarios, the data-driven reachablesets of a robot can be prohibitively conservative due to theinherent noise in the robot’s historical measurement data. Inthe same scenarios, we often have side information about therobot’s expected motion (e.g., limits on how much a robotcan move in a one-time step) that could be useful for furtherspecifying the reachability analysis. In this work, we showthat if we can model this side information using a signaltemporal logic (STL) fragment, we can constrain the datadriven reachability analysis and safely limit the conservatismof the computed reachable sets. Moreover, we provide formalguarantees that, even after incorporating side information, thecomputed reachable sets still properly over-approximate therobot’s future states. Lastly, we empirically validate the practicality of the over-approximation by computing constrained,data-driven reachable sets for the Small-Vehicles-for-Autonomy(SVEA) hardware platform in two driving scenarios.
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| 6. |
- Alanwar, Amr, et al.
(författare)
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Logical Zonotopes : A Set Representation for the Formal Verification of Boolean Functions
- 2023
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Ingår i: 2023 62nd IEEE Conference on Decision and Control, CDC 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 60-66
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Konferensbidrag (refereegranskat)abstract
- A logical zonotope, which is a new set representation for binary vectors, is introduced in this paper. A logical zonotope is constructed by XORing a binary vector with a combination of other binary vectors called generators. Such a zonotope can represent up to 2γ binary vectors using only γ generators. It is shown that logical operations over sets of binary vectors can be performed on the zonotopes' generators and, thus, significantly reduce the computational complexity of various logical operations (e.g., XOR, NAND, AND, OR, and semi-tensor products). Similar to traditional zonotopes' role in the formal verification of dynamical systems over real vector spaces, logical zonotopes can efficiently analyze discrete dynamical systems defined over binary vector spaces. We illustrate the approach and its ability to reduce the computational complexity in two use cases: (1) encryption key discovery of a linear feedback shift register and (2) safety verification of a road traffic intersection protocol.
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| 7. |
- Alimena, Juliette, et al.
(författare)
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Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
- 2020
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:9
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Tidskriftsartikel (refereegranskat)abstract
- Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
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| 8. |
- Chen, Xiao, et al.
(författare)
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Safe Intersection Coordination with Mixed Traffic : From Estimation to Control
- 2023
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose an integrated framework for safe intersection coordination of connected and automated vehicles (CAVs) in mixed traffic. An intelligent intersection is introduced as a central node to orchestrate state data sharing among connected agents and enable CAV to acknowledge the presence of human-driven vehicles (HDVs) beyond the line of sight of onboard sensors. Since state data shared between agents might be uncertain or delayed, we design the intelligent intersection to safely compensate for these uncertainties and delays using robust set estimation and forward reachability analysis. When the intersection receives state data from an agent, it first generates a zonotope to capture the possible measurement noise in the state estimate. Then, to compensate for communication and processing delays, it uses forward reachability analysis to enlarge the set to capture all the possible states the agent could have occupied throughout the delays. Finally, using the resulting set as the initial condition, a distributed model predictive control onboard the CAV will plan an invariant safe motion by considering the worst-case behavior of human drivers. As a result, the vehicle is guaranteed to be safe while driving through the intersection. A prototype of our proposed framework is implemented using.
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| 9. |
- Fang, Evandro F., et al.
(författare)
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A research agenda for ageing in China in the 21st century (2nd edition): Focusing on basic and translational research, long-term care, policy and social networks.
- 2020
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Ingår i: Ageing Research Reviews. - : Elsevier BV. - 1568-1637. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- One of the key issues facing public healthcare is the global trend of an increasingly ageing society which continues to present policy makers and caregivers with formidable healthcare and socio-economic challenges. Ageing is the primary contributor to a broad spectrum of chronic disorders all associated with a lower quality of life in the elderly. In 2019, the Chinese population constituted 18 % of the world population, with 164.5 million Chinese citizens aged 65 and above (65+), and 26 million aged 80 or above (80+). China has become an ageing society, and as it continues to age it will continue to exacerbate the burden borne by current family and public healthcare systems. Major healthcare challenges involved with caring for the elderly in China include the management of chronic non-communicable diseases (CNCDs), physical frailty, neurodegenerative diseases, cardiovascular diseases, with emerging challenges such as providing sufficient dental care, combating the rising prevalence of sexually transmitted diseases among nursing home communities, providing support for increased incidences of immune diseases, and the growing necessity to provide palliative care for the elderly. At the governmental level, it is necessary to make long-term strategic plans to respond to the pressures of an ageing society, especially to establish a nationwide, affordable, annual health check system to facilitate early diagnosis and provide access to affordable treatments. China has begun work on several activities to address these issues including the recent completion of the of the Ten-year Health-Care Reform project, the implementation of the Healthy China 2030 Action Plan, and the opening of the National Clinical Research Center for Geriatric Disorders. There are also societal challenges, namely the shift from an extended family system in which the younger provide home care for their elderly family members, to the current trend in which young people are increasingly migrating towards major cities for work, increasing reliance on nursing homes to compensate, especially following the outcomes of the ‘one child policy’ and the ‘empty-nest elderly’ phenomenon. At the individual level, it is important to provide avenues for people to seek and improve their own knowledge of health and disease, to encourage them to seek medical check-ups to prevent/manage illness, and to find ways to promote modifiable health-related behaviors (social activity, exercise, healthy diets, reasonable diet supplements) to enable healthier, happier, longer, and more productive lives in the elderly. Finally, at the technological or treatment level, there is a focus on modern technologies to counteract the negative effects of ageing. Researchers are striving to produce drugs that can mimic the effects of ‘exercising more, eating less’, while other anti-ageing molecules from molecular gerontologists could help to improve ‘healthspan’ in the elderly. Machine learning, ‘Big Data’, and other novel technologies can also be used to monitor disease patterns at the population level and may be used to inform policy design in the future. Collectively, synergies across disciplines on policies, geriatric care, drug development, personal awareness, the use of big data, machine learning and personalized medicine will transform China into a country that enables the most for its elderly, maximizing and celebrating their longevity in the coming decades. This is the 2nd edition of the review paper (Fang EF et al., Ageing Re. Rev. 2015).
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| 10. |
- Gao, Yulong, et al.
(författare)
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Reachability-based Human-in-the-Loop Control with Uncertain Specifications
- 2020
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Ingår i: IFAC PAPERSONLINE. - : Elsevier BV. - 2405-8963. ; , s. 1880-1887
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Konferensbidrag (refereegranskat)abstract
- We propose a shared autonomy approach for implementing human operator decisions onto an automated system during multi-objective missions, while guaranteeing safety and mission completion. A mission is specified as a set of linear temporal logic (LTL) formulae. Then, using a novel correspondence between LTL and reachability analysis, we synthesize a set of controllers for assisting the human operator to complete the mission, while guaranteeing that the system maintains specified spatial and temporal properties. We assume the human operator's exact preference of how to complete the mission is unknown. Instead, we use a datadriven approach to infer and update the automated system's internal belief of which specified objective the human intends to complete. If, while the human is operating the system, she provides inputs that violate any of the invariances prescribed by the LTL formula, our verified controller will use its internal belief of the human operator's intended objective to guide the operator back on track. Moreover, we show that as long as the specifications are initially feasible, our controller will stay feasible and can guide the human to complete the mission despite some unexpected human errors. We illustrate our approach with a simple, but practical, experimental setup where a remote operator is parking a vehicle in a parking lot with multiple parking options. In these experiments, we show that our approach is able to infer the human operator's preference over parking spots in real-time and guarantee that the human will park in the spot safely.
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| 11. |
- Gao, Yulong, et al.
(författare)
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Risk-Aware Optimal Control for Automated Overtaking With Safety Guarantees
- 2021
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Ingår i: IEEE Transactions on Control Systems Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 1063-6536 .- 1558-0865. ; , s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- This article proposes a solution to the overtaking control problem where an automated vehicle tries to overtake another vehicle with uncertain motion. Our solution allows the automated vehicle to robustly overtake a human-driven vehicle under certain assumptions. Uncertainty in the predicted motion makes the automated overtaking problem hard to solve due to feasibility issues that arise from the fact that the overtaken vehicle (e.g., a vehicle driven by an aggressive driver) may accelerate to prevent the overtaking maneuver. To counteract them, we introduce the weak assumption that the predicted velocity of the overtaken vehicle respects a supermartingale, meaning that its velocity is not increasing in expectation during the maneuver. We show that this formulation presents a natural notion of risk. Based on the martingale assumption, we perform a risk-aware reachability analysis by analytically characterizing the predicted collision probability. Then, we design a risk-aware optimal overtaking algorithm with guaranteed levels of collision avoidance. Finally, we illustrate the effectiveness of the proposed algorithm with a simulated example.
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| 12. |
- Gao, Yulong, et al.
(författare)
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Temporal Logic Trees for Model Checking and Control Synthesis of Uncertain Discrete-time Systems
- 2021
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Ingår i: IEEE Transactions on Automatic Control. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9286 .- 1558-2523. ; , s. 1-1
-
Tidskriftsartikel (refereegranskat)abstract
- We propose algorithms for performing model checking and control synthesis for discrete-time uncertain systems under linear temporal logic (LTL) specifications. We construct temporal logic trees (TLT) from LTL formulae via reachability analysis. In contrast to automaton-based methods, the construction of the TLT is abstraction-free for infinite systems, that is, we do not construct discrete abstractions of the infinite systems. Moreover, for a given transition system and an LTL formula, we prove that there exist both a universal TLT and an existential TLT via minimal and maximal reachability analysis, respectively. We show that the universal TLT is an underapproximation for the LTL formula and the existential TLT is an overapproximation. We provide sufficient conditions and necessary conditions to verify whether a transition system satisfies an LTL formula by using the TLT approximations. As a major contribution of this work, for a controlled transition system and an LTL formula, we prove that a controlled TLT can be constructed from the LTL formula via control-dependent reachability analysis. Based on the controlled TLT, we design an online control synthesis algorithm, under which a set of feasible control inputs can be generated at each time step. We also prove that this algorithm is recursively feasible. We illustrate the proposed methods for both finite and infinite systems and highlight the generality and online scalability with two simulated examples.
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| 13. |
- Gasperetti, Alessio, et al.
(författare)
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Efficacy of Catheter Ablation for Atrial Arrhythmias in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy - A Multicenter Study
- 2021
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 10:21
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Tidskriftsartikel (refereegranskat)abstract
- Background: Atrial arrhythmias are present in up to 20% of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Catheter ablation (CA) is an effective treatment for atrial arrhythmias in the general population. Data regarding CA for atrial arrhythmias in ARVC are scarce. Objective: To assess the safety and efficacy of CA for atrial arrhythmias in patients with ARVC. Methods: In this international collaborative effort, all patients with a definite diagnosis of ARVC undergoing CA for atrial fibrillation (AF), focal atrial tachycardia (AT), or cavotricuspid isthmus (CTI)-dependent atrial flutter (AFl) were extracted from twelve ARVC registries. Demographic, periprocedural, and long-term arrhythmic outcome data were collected. Results: Thirty-seven patients were enrolled in the study (age 50.2 & PLUSMN; 16.6 years, male 84%, CHA(2)DS(2)VASc 1 (1,2), HAS-BLED 0 (0-2)). The arrhythmia leading to CA was AF in 23 (62%), focal left AT in 5 (14%), and CTI-dependent AFl in 9 (24%). Acute procedural success was achieved in all procedures but one (n = 1 focal left AT; 97% acute success). The median follow-up period was 27 (13-67) months, and 96%, 74%, and 61% of patients undergoing AF ablation were free from any atrial arrhythmia recurrence after a single procedure at 6 months, 12 months, and last follow-up, respectively. After focal AT ablation, freedom from atrial arrhythmia recurrence was 80%, 80%, and 60% at 6 months, 12 months, and last follow-up, respectively. All patients undergoing CTI ablation were free from atrial arrhythmia recurrences at 6 months, with 89% single-procedural arrhythmic freedom at last follow-up. One major complication (2.7%; PV stenosis requiring PV stenting) occurred. Conclusions: CA is safe and effective in managing atrial arrhythmias in patients with ARVC, with success rates comparable to the general population.
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| 14. |
- Jiang, Frank, et al.
(författare)
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Ensuring safety for vehicle parking tasks using Hamilton-Jacobi reachability analysis
- 2020
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Ingår i: Proceedings of the IEEE Conference on Decision and Control. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 1416-1421
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose an approach for ensuring the safety of a vehicle throughout a parking task, even when the vehicle is being operated at varying levels of automation. We start by specifying a vehicle parking task using linear temporal logic formulae that can be model checked for feasibility. The model-checking is facilitated by the construction of a temporal logic tree via Hamilton-Jacobi reachability analysis. Once we know the parking task is feasible for our vehicle model, we utilize the constructed temporal logic tree to directly synthesize control sets. Our approach synthesizes control sets that are least-restrictive in the context of the specification, since they permit any control inputs that are guaranteed not to violate the specification. This least-restrictive characteristic allows for the application of our approach to vehicles under different modes of operation (e.g., human-in-the-loop shared autonomy or fully-automated schemes). Implementing in both simulation and on hardware, we demonstrate the approach's potential for ensuring the safety of vehicles throughout parking tasks, whether they are operated by humans or automated driving systems.
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| 15. |
- Jiang, Frank, et al.
(författare)
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Human-Centered Design for Safe Teleoperation of Connected Vehicles
- 2020
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Ingår i: IFAC papersonline. - : Elsevier BV. - 2405-8963. ; , s. 224-231
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a framework for the safe teleoperation of connected vehicles by remote human operators. The proposed framework combines model-checking, reachability analysis, and human factor design into a unified approach that checks the feasibility of linear temporal logic (LTL) specified teleoperation tasks, guarantees safety throughout the execution of the tasks, and keeps the remote operator as the primary decision maker in the control loop. We apply the general approach to a remote parking example to illustrate the framework. Then, to evaluate the framework's benefits and usability, we conduct a user study on an experimental remote control operator's room and a 1/10th scale vehicle. In the user study, we validate the approach's ability to ensure the completion of LTL-specified tasks and gain initial insight into whether human users find the teleoperation system intuitive.
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| 16. |
- Jiang, Frank, et al.
(författare)
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Safe Teleoperation of Connected and Automated Vehicles
- 2023
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Ingår i: Cyber–Physical–Human Systems. - : Wiley. ; , s. 251-272
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter, we discuss teleoperation systems for connected and automated vehicles and overview the research around making these systems safe and human-centric. In recent years, teleoperation by human operators has become an important modality of supervision for connected and automated vehicles. While automated driving systems continue to mature and handle a rich variety of scenarios, we are continually reminded that unplanned exceptions and deviations from the driving systems' operational design domain – be it unpredictable human behavior or unmodeled kangaroo mechanics – can create potentially unsafe situations for automated vehicles. From decades of research in human factors in air traffic control, we know that we can robustify against automation failure by closely integrating human operators into our automation systems. To this end, teleoperation systems have become of great interest to the connected and automated vehicle research community. By establishing teleoperation systems, we can ensure that when a vehicle experiences automation failure, we have a fallback system where a human operator is able to handle the failure. Moreover, due to the recent introduction of ultra-reliable and low latency communication in 5G networks, we know that wireless communication channels are reliable enough to safely deploy such fallback systems. Since the human operator is remote, we can potentially set up “control towers” for vehicles where a few operators can manage many vehicles. However, to reach this potential, there are several safety and cyber–physical–human system design challenges that need to be addressed. In this chapter, we will introduce these challenges and discuss the recent research that has been conducted to solve these challenges. Furthermore, we will discuss the future research directions that will further enhance the safety of teleoperation systems.
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| 17. |
- Jiang, Frank, et al.
(författare)
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SVEA : an experimental testbed for evaluating V2X use-cases
- 2022
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Ingår i: 2022 IEEE 25TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3484-3489
-
Konferensbidrag (refereegranskat)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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| 18. |
- Jiang, Qing-Dong, et al.
(författare)
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Geometric Induction in Chiral Superconductors
- 2020
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 124:19
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Tidskriftsartikel (refereegranskat)abstract
- We consider a number of effects due to the interplay of superconductivity, electromagnetism, and elasticity, which are unique for thin membranes of layered chiral superconductors. Some of them should be within the reach of present technology, and could be useful for characterizing materials. More speculatively, the enriched control of Josephson junctions they afford might find useful applications.
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| 19. |
- Kostka, Kristin, et al.
(författare)
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Unraveling COVID-19: A Large-Scale Characterization of 4.5 Million COVID-19 Cases Using CHARYBDIS.
- 2022
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Ingår i: Clinical epidemiology. - 1179-1349. ; 14, s. 369-384
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Tidskriftsartikel (refereegranskat)abstract
- Routinely collected real world data (RWD) have great utility in aiding the novel coronavirus disease (COVID-19) pandemic response. Here we present the international Observational Health Data Sciences and Informatics (OHDSI) Characterizing Health Associated Risks and Your Baseline Disease In SARS-COV-2 (CHARYBDIS) framework for standardisation and analysis of COVID-19 RWD.We conducted a descriptive retrospective database study using a federated network of data partners in the United States, Europe (the Netherlands, Spain, the UK, Germany, France and Italy) and Asia (South Korea and China). The study protocol and analytical package were released on 11th June 2020 and are iteratively updated via GitHub. We identified three non-mutually exclusive cohorts of 4,537,153 individuals with a clinical COVID-19 diagnosis or positive test, 886,193 hospitalized with COVID-19, and 113,627 hospitalized with COVID-19 requiring intensive services.We aggregated over 22,000 unique characteristics describing patients with COVID-19. All comorbidities, symptoms, medications, and outcomes are described by cohort in aggregate counts and are readily available online. Globally, we observed similarities in the USA and Europe: more women diagnosed than men but more men hospitalized than women, most diagnosed cases between 25 and 60 years of age versus most hospitalized cases between 60 and 80 years of age. South Korea differed with more women than men hospitalized. Common comorbidities included type 2 diabetes, hypertension, chronic kidney disease and heart disease. Common presenting symptoms were dyspnea, cough and fever. Symptom data availability was more common in hospitalized cohorts than diagnosed.We constructed a global, multi-centre view to describe trends in COVID-19 progression, management and evolution over time. By characterising baseline variability in patients and geography, our work provides critical context that may otherwise be misconstrued as data quality issues. This is important as we perform studies on adverse events of special interest in COVID-19 vaccine surveillance.
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| 20. |
- Maasri, Alain, et al.
(författare)
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A global agenda for advancing freshwater biodiversity research
- 2022
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 25:2, s. 255-263
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Tidskriftsartikel (refereegranskat)abstract
- Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.
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| 21. |
- Schweinsberg, Martin, et al.
(författare)
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Same data, different conclusions : Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis
- 2021
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Ingår i: Organizational Behavior and Human Decision Processes. - : Elsevier BV. - 0749-5978 .- 1095-9920. ; 165, s. 228-249
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Tidskriftsartikel (refereegranskat)abstract
- In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists' gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for orga-nizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed.
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| 22. |
- Stefansson, Elis, et al.
(författare)
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Modeling the decision-making in human driver overtaking
- 2020
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Ingår i: IFAC PAPERSONLINE. - : Elsevier BV. - 2405-8963. ; , s. 15338-15345
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Konferensbidrag (refereegranskat)abstract
- We propose models for the decision-making process of human drivers in an overtaking scenario. First, we mathematically formalize the overtaking problem as a decision problem with perceptual uncertainty. Then, we propose and numerically analyze risk-agnostic and risk-aware decision models, which are able to judge whether an overtaking is desirable or not. We show how a driver's decision-making time and confidence level can be primarily characterized through two model parameters, which collectively represent human risk-taking behavior. We detail an experimental testbed for evaluating the decision-making process in the overtaking scenario. Finally, we present some preliminary experimental results from two human drivers.
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| 23. |
- Söderlund, August, et al.
(författare)
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Data-Driven Reachability Analysis of Pedestrians Using Behavior Modes
- 2023
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Ingår i: 2023 IEEE 26th International Conference on Intelligent Transportation Systems, ITSC 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 4025-4031
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a data-driven approach for safely predicting the future state sets of pedestrians. Previous approaches to predicting the future state sets of pedestrians either do not provide safety guarantees or are overly conservative. Moreover, an additional challenge is the selection or identification of a model that sufficiently captures the motion of pedestrians. To address these issues, this paper introduces the idea of splitting previously collected, historical pedestrian trajectories into different behavior modes for performing data-driven reachability analysis. Through this proposed approach, we are able to use data-driven reachability analysis to capture the future state sets of pedestrians, while being less conservative and still maintaining safety guarantees. Furthermore, this approach is modular and can support different approaches for behavior splitting. To illustrate the efficacy of the approach, we implement our method with a basic behavior-splitting module and evaluate the implementation on an open-source data set of real pedestrian trajectories. In this evaluation, we find that the modal reachable sets are less conservative and more descriptive of the future state sets of the pedestrian.
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| 24. |
- Walker, Anthony P., et al.
(författare)
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Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2
- 2021
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Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 229:5, s. 2413-2445
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric carbon dioxide concentration ([CO2]) is increasing, which increases leaf‐scale photosynthesis and intrinsic water‐use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO2] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO2]‐driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2] (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre‐industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.
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| 25. |
- Wang, Jiang, et al.
(författare)
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Multi-body effects in a coarse-grained protein force field
- 2021
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 154:16
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Tidskriftsartikel (refereegranskat)abstract
- The use of coarse-grained (CG) models is a popular approach to study complex biomolecular systems. By reducing the number of degrees of freedom, a CG model can explore long time- and length-scales inaccessible to computational models at higher resolution. If a CG model is designed by formally integrating out some of the system’s degrees of freedom, one expects multi-body interactions to emerge in the effective CG model’s energy function. In practice, it has been shown that the inclusion of multi-body terms indeed improves the accuracy of a CG model. However, no general approach has been proposed to systematically construct a CG effective energy that includes arbitrary orders of multi-body terms. In this work, we propose a neural network based approach to address this point and construct a CG model as a multi-body expansion. By applying this approach to a small protein, we evaluate the relative importance of the different multi-body terms in the definition of an accurate model. We observe a slow convergence in the multi-body expansion, where up to five-body interactions are needed to reproduce the free energy of an atomistic model.
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| 26. |
- Yu, Pian, et al.
(författare)
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Online control synthesis for uncertain systems under signal temporal logic specifications
- 2024
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Ingår i: The international journal of robotics research. - : SAGE Publications. - 0278-3649 .- 1741-3176. ; 43:6, s. 765-790
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Tidskriftsartikel (refereegranskat)abstract
- Signal temporal logic (STL) formulas have been widely used as a formal language to express complex robotic specifications, thanks to their rich expressiveness and explicit time semantics. Existing approaches for STL control synthesis suffer from limited scalability with respect to the task complexity and lack of robustness against the uncertainty, for example, external disturbances. In this paper, we study the online control synthesis problem for uncertain discrete-time systems subject to STL specifications. Different from existing techniques, we propose an approach based on STL, reachability analysis, and temporal logic trees. First, based on a real-time version of STL semantics, we develop the notion of tube-based temporal logic tree (tTLT) and its recursive (offline) construction algorithm. We show that the tTLT is an under-approximation of the STL formula, in the sense that a trajectory satisfying a tTLT also satisfies the corresponding STL formula. Then, an online control synthesis algorithm is designed using the constructed tTLT. It is shown that when the STL formula is robustly satisfiable and the initial state of the system belongs to the initial root node of the tTLT, it is guaranteed that the trajectory generated by the control synthesis algorithm satisfies the STL formula. We validate the effectiveness of the proposed approach by several simulation examples and further demonstrate its practical usability on a hardware experiment. These results show that our approach is able to handle complex STL formulas with long horizons and ensure the robustness against the disturbances, which is beyond the scope of the state-of-the-art STL control synthesis approaches.
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| 27. |
- Yuan, Ye, et al.
(författare)
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Machine discovery of partial differential equations from spatiotemporal data: A sparse Bayesian learning framework
- 2023
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Ingår i: Chaos. - : AIP Publishing. - 1054-1500 .- 1089-7682. ; 33:11
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a general framework, namely, Sparse Spatiotemporal System Discovery ( S 3 d ), for discovering dynamical models given by Partial Differential Equations (PDEs) from spatiotemporal data. S 3 d is built on the recent development of sparse Bayesian learning, which enforces sparsity in the estimated PDEs. This approach enables a balance between model complexity and fitting error with theoretical guarantees. The proposed framework integrates Bayesian inference and a sparse priori distribution with the sparse regression method. It also introduces a principled iterative re-weighted algorithm to select dominant features in PDEs and solve for the sparse coefficients. We have demonstrated the discovery of the complex Ginzburg-Landau equation from a traveling-wave convection experiment, as well as several other PDEs, including the important cases of Navier-Stokes and sine-Gordon equations, from simulated data.
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| 28. |
- Zhao, Lin, et al.
(författare)
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Remote Driving of Road Vehicles : A Survey of Driving Feedback, Latency, Support Control, and Real Applications
- 2024
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Ingår i: IEEE Transactions on Intelligent Vehicles. - : IEEE. - 2379-8858 .- 2379-8904.
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Tidskriftsartikel (refereegranskat)abstract
- This literature survey explores the domain of remote driving of road vehicles within autonomous vehicles, focusing on challenges and state-of-the-art solutions related to driving feedback, latency, support control, as well as remote driving platform and real applications. The advancement towards Level-5 autonomy faces challenges, including sensor reliability and diverse scenario feasibility. Currently, remote driving is identified as vital for commercialization, however, it comes with challenges like low situational awareness, latency, and a lack of comprehensive feedback mechanisms. Solutions proposed include enhancing visual feedback, developing haptic feedback, employing prediction techniques, and use control methods to support driver. This paper reviews the existing literature on remote driving in these fields, revealing research gaps and areas for future studies. Additionally, this paper reviews the industry applications of remote driving and shows the state-of-art use cases.
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