| 1. |
- Blanco, A., et al.
(författare)
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Performance of timing resistive plate chambers with relativistic neutrons from 300 to 1500 MeV
- 2015
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Ingår i: Journal of Instrumentation. - : IOP Publishing. - 1748-0221. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic neutrons produced from a deuteron beam of varying energy (300 to 1500 AMeV) in experiment S406 at GSI, Darmstad, Germany. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Measurements of the time of flight jitter of neutrons, in the mentioned energy range, point to a contribution of the resistive plate chamber in the order of 150 ps, independent of the neutron energy.
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| 2. |
- Fay, Dominik, et al.
(författare)
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Adaptive Hyperparameter Selection for Differentially Private Gradient Descent
- 2023
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Ingår i: Transactions on Machine Learning Research. - 2835-8856.
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Tidskriftsartikel (refereegranskat)abstract
- We present an adaptive mechanism for hyperparameter selection in differentially private optimization that addresses the inherent trade-off between utility and privacy. The mechanism eliminates the often unstructured and time-consuming manual effort of selecting hyperparameters and avoids the additional privacy costs that hyperparameter selection otherwise incurs on top of that of the actual algorithm.We instantiate our mechanism for noisy gradient descent on non-convex, convex and strongly convex loss functions, respectively, to derive schedules for the noise variance and step size. These schedules account for the properties of the loss function and adapt to convergence metrics such as the gradient norm. When using these schedules, we show that noisy gradient descent converges at essentially the same rate as its noise-free counterpart. Numerical experiments show that the schedules consistently perform well across a range of datasets without manual tuning.
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| 3. |
- Johansson, Emil, et al.
(författare)
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Pentavalent Sialic Acid Conjugates Block Coxsackievirus A24 Variant and Human Adenovirus Type 37-Viruses That Cause Highly Contagious Eye Infections
- 2020
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Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 15:10, s. 2683-2691
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Tidskriftsartikel (refereegranskat)abstract
- Coxsackievirus A24 variant (CVA24v) and human adenovirus 37 (HAdV-37) are leading causative agents of the severe and highly contagious ocular infections acute hemorrhagic conjunctivitis and epidemic keratoconjunctivitis, respectively. Currently, neither vaccines nor antiviral agents are available for treating these diseases, which affect millions of individuals worldwide. CVA24v and HAdV-37 utilize sialic acid as attachment receptors facilitating entry into host cells. Previously, we and others have shown that derivatives based on sialic acid are effective in preventing HAdV-37 binding and infection of cells. Here, we designed and synthesized novel pentavalent sialic acid conjugates and studied their inhibitory effect against CVA24v and HAdV-37 binding and infection of human corneal epithelial cells. The pentavalent conjugates are the first reported inhibitors of CVA24v infection and proved efficient in blocking HAdV-37 binding. Taken together, the pentavalent conjugates presented here form a basis for the development of general inhibitors of these highly contagious ocular pathogens.
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| 4. |
- Johansson, Mikael, 1987, et al.
(författare)
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Action-Meaning Networks - A Novel Methodology to Identify Unsafe Use of Driving Automation
- 2023
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Ingår i: HUMANIST Conference. - 9782953171273 ; 8, s. 28-34
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Konferensbidrag (refereegranskat)abstract
- The transition from manual to automated driving holds the promise of safer traffic and numerous societal benefits. However, ensuring the safe usage of driving automation is crucial for realizing these promises and facilitating a successful transition. Introducing driving automation into vehicles presents challenges for drivers, often resulting in behavioural adaptations that undermine the anticipated advantages. Therefore, it is imperative to understand how drivers engage with driving automation systems (DAS) and the significance they attribute to them, as the meaning assigned to these systems significantly influences their usage. This paper presents a novel methodology aimed at investigating the utilization of driving automation by examining both users' actions and the meaning they associate with the system during operation and organizing them into action-meaning networks. To illustrate this methodology, it was applied to takeover and hand-over requests, on a previously collected dataset from an on-road study. By employing this methodology, usage patterns were revealed, enabling the distinction of how drivers' actions and comprehension evolved over time and with repeated interaction. Additionally, unsafe actions and meanings associated with the interaction with the DAS were identified, highlighting potential hazards in long-term or alternative usage scenarios. Based on the evaluation of the results, it is reasonable to conclude that this methodology has the potential to complement existing approaches. By uncovering usage patterns and associated meanings of users’ interaction with DAS, it has the potential to facilitate the development of strategies to ensure safe usage and promote a positive user experience with such systems.
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| 5. |
- Johansson, Mikael, 1987, et al.
(författare)
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Automation as an enabler: Passengers’ experience of travelling with a full-length automated bus and their expectations of a future public transport system
- 2023
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Ingår i: Transportation Research Procedia. - 2352-1465 .- 2352-1457. ; 72, s. 957-964
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Konferensbidrag (refereegranskat)abstract
- Twenty-two frequent public transport users experienced travelling with a fully automated, full-length bus on a test course that included nine simulated everyday traffic situations. Most participants experienced the journey as very positive and their trust in the automated system was high. In general, they were positive about using automated buses in the future but believed that this would not improve their travelling experience or change their travel behaviour without additional modifications to the system, such as dedicated public transport lanes etc. Many believed that the introduction of automated buses could create conditions for increased access to transport in rural areas and that the automated technology might enable new services that would have a great impact on public transport development, contributing a more individual, efficient and flexible public transport system.
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| 6. |
- Johansson, Mikael, 1987, et al.
(författare)
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The decline of user experience in transition from automated driving to manual driving
- 2021
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Ingår i: Information (Switzerland). - Basel : MDPI AG. - 2078-2489. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Automated driving technologies are rapidly being developed. However, until vehicles are fully automated, the control of the dynamic driving task will be shifted between the driver and automated driving system. This paper aims to explore how transitions from automated driving to manual driving affect user experience and how that experience correlates to take-over performance. In the study 20 participants experienced using an automated driving system during rush-hour traffic in the San Francisco Bay Area, CA, USA. The automated driving system was available in congested traffic situations and when active, the participants could engage in non-driving related activities. The participants were interviewed afterwards regarding their experience of the transitions. The findings show that most of the participants experienced the transition from automated driving to manual driving as negative. Their user experience seems to be shaped by several reasons that differ in temporality and are derived from different phases during the transition process. The results regarding correlation between participants’ experience and take-over performance are inconclusive, but some trends were identified. The study highlights the need for new design solutions that do not only improve drivers’ take-over performance, but also enhance user experience during take-over requests from automated to manual driving.
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| 7. |
- Johansson, Mikael, 1987, et al.
(författare)
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To Drive or Not to Drive – When Users Prefer to Use Automated Driving Functions
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Vehicle automation is rapidly developing and getting more and more advanced. There will however be some time until vehicles are fully automated and able to drive everywhere. Until then, Automated Vehicles (AVs) will only be able to operate under certain conditions where the automation is capable of performing the required driving operations. Currently, manufacturers are testing and developing AV functions that are intended to operate under specific conditions. However, little is known about where users find a value in using driving automation, and how the experience of such functions affects the potential usage scenarios that people see. Therefore, this paper has investigated where and when users would prefer to use AV functions, both before and after using an AV, based on a study that was conducted using a partially AV with two levels of automation on public roads in California, USA. The results are compiled into a user journey, to illustrate during which conditions the participants believe they would benefit from using automated vehicle functions the most, as well as preferences that users have towards the two functions regarding conditions and use. The results show that the participants would find a value in having this kind of functions during different traffic conditions (e.g. road type or specific traffic situations), and external or internal conditions (e.g. time of day or mood of user). The functions were mostly preferred to be of value during congested traffic situations or during longer trips, where the users would like to use their time differently than driving. The potential added value to the user experience when having driving automation in the car was believed to be either relaxation, meaning time to wind down, and physical and mental relief from stressful traffic situations, as well as a promise of efficiency and being able to do other activities by not having to focus on the driving task. These findings can give developers insights about a potential focus during the development of AV functions, in accordance to the needs and values users ascribe to them.
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| 8. |
- Machado, J., et al.
(författare)
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Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV
- 2015
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 10:1, s. C01043-
-
Tidskriftsartikel (refereegranskat)abstract
- A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm 2 , is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C 2 H 2 F 4 and 10% SF 6 . The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm 2 area.
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| 9. |
- Novakazi, Fjolle, 1987, et al.
(författare)
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Levels of what? Investigating drivers' understanding of different levels of automation in vehicles
- 2021
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Ingår i: Journal of Cognitive Engineering and Decision Making. - : SAGE Publications. - 1555-3434 .- 2169-5032. ; 15:2-3, s. 116-132
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Tidskriftsartikel (refereegranskat)abstract
- Extant levels of automation (LoAs) taxonomies describe variations in function allocations between the driver and the driving automation system (DAS) from a technical perspective. However, these taxonomies miss important human factors issues and when design decisions are based on them, the resulting interaction design leaves users confused. Therefore, the aim of this paper is to describe how users perceive different DASs by eliciting insights from an empirical driving study facilitating a Wizard-of-Oz approach, where 20 participants were interviewed after experiencing systems on two different LoAs under real driving conditions. The findings show that participants talked about the DAS by describing different relationships and dependencies between three different elements: the context (traffic conditions, road types), the vehicle (abilities, limitations, vehicle operations), and the driver (control, attentional demand, interaction with displays and controls, operation of vehicle), each with associated aspects that indicate what users identify as relevant when describing a vehicle with automated systems. Based on these findings, a conceptual model is proposed by which designers can differentiate LoAs from a human-centric perspective and that can aid in the development of design guidelines for driving automation.
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| 10. |
- Novakazi, Fjolle, 1987, et al.
(författare)
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Who's in charge?: The influence of perceived control on responsibility and mode awareness in driving automation
- 2021
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Ingår i: IT - Information Technology. - : Walter de Gruyter GmbH. - 1611-2776 .- 2196-7032. ; 62:2, s. 77-85
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Tidskriftsartikel (refereegranskat)abstract
- Fully automated drive still lies far ahead in the future. Therefore, vehicles with multiple modes of operation will not disappear fully as many road types, traffic and weather conditions will not allow fully automated drive. Instead, fragmented trips with regard to automation will prevail, where drivers will have different levels of automation available at different times. Given this scenario and the complexity of vehicles offering multiple levels of automation with different driving modes depending on prevailing conditions, the need for drivers to understand their responsibility during the different modes becomes critical. The aim of this paper is to contribute to further understanding of how perceived control influences the driver's mode awareness of and responsibility for the driving task by reporting on an on-road Wizard-of-Oz study under real driving conditions. The results show that when confronted with a vehicle offering both a level 2 and a level 4 driving automation system, drivers have difficulty in determining whether control is allocated to them or to the system. Further results show that perceived control and responsibility for the driving task are closely linked, and that the driver's perception of the driving system influence how they interact with it. Finally, conclusions are drawn regarding the way perceived control influences mode awareness when interacting with a vehicle that features multiple levels of automation.
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