| 1. |
- Lundkvist, Erik, Fil Dr, 1978-, et al.
(författare)
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Relating Competitive Golfers’ Perceived Emotions and Performance
- 2021
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Ingår i: Perceptual and Motor Skills. - Thousand Oaks : Sage Publications. - 0031-5125 .- 1558-688X. ; 128:4, s. 1549-1568
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Tidskriftsartikel (refereegranskat)abstract
- The present study examined relationships between golfers’ self-perceived emotions (e.g., irritability, nervousness, tension), task-oriented coping, perceived control, and performance during a golf competition. We implemented a process-oriented golf analysis in which competitors rated these variables hole-by-hole in a competitive golf round. Within a two-level Bayesian multivariate autoregressive model, we showed that (a) within persons, emotions and task-oriented coping were reactions that stemmed from performance on the previous hole; and (b) between persons, player skill level predicted both better scores and the ability to limit the influence of negative affect on performance. These findings highlight the complex nature of the relationship between emotions and performance. Future studies might use a similarly ecologically valid research design to more precisely measure aspects of time and potentially moderating effects of player skill level and personality. An increased understanding of the dynamic relationship between emotions and performance can promote the development of effective psychological interventions for optimal performance outcomes.
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| 2. |
- Westin, Jonas, et al.
(författare)
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Analyzing model uncertainty and economies of scale of the Swedish National Freight model to changes in transport demand
- 2016
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Ingår i: European Journal of Transport and Infrastructure Research. - : Editorial Board EJTIR. - 1567-7133 .- 1567-7141. ; 16:4, s. 619-632
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the paper is to analyze model uncertainty and economies of scale of the Swedish national freight transport model system Samgods to changes in its zone-to-zone base matrices. Even though economies of scale is important for freight transport, few studies analyze model uncertainty and economies of scale at a national level. Compared to many large scale network-based freight models working on aggregated transport flows, an important feature in Samgods is that it simulates logistics behavior at a disaggregated firm level. The paper studies effects on total tonne- and vehicle-kilometre, modal split, consolidation and logistics costs when the base matrices are scaled up and down and estimates economies of scale for Swedish freight transports. The results indicate that the logistics model can find new logistics solutions for larger demand volumes, mainly by shifting freight to sea transport. If transport volume increases with one percent, average logistics cost per tonne is reduced by around 0.5 percent. Part of the cost reduction comes from increased consolidation of shipments due to larger transport volumes. The results derived in the paper can serve as a reference for empirical validation and comparisons with other large scale freight models. The paper is a first contribution that tries to fill the knowledge gap on the impact of base matrices on transport model outcomes, such as economies of scale, in the context of a full-fledged real-world freight transport model.
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| 3. |
- Eriksson, Lars, et al.
(författare)
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Performance and presence with head-movement produced motion parallax in simulated driving
- 2015
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Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 34, s. 54-64
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Tidskriftsartikel (refereegranskat)abstract
- Driving simulator studies can reveal relevant and valid aspects of driving behavior, but underestimation of distance and speed can negatively affect the driver's performance, such as in performance of overtaking. One possible explanation for the underestimation of distance and speed is that two-dimensional projection of the visual scene disrupts the monocular-based illusory depth because of conflicting binocular and monocular information of depth. A possible solution might involve the strengthening of the monocular information so that the binocular information becomes less potent.In the present study, we used an advanced high-fidelity driving simulator to investigate whether adding the visual depth information of motion parallax from head movement affects sense of presence, judgment of distance and speed, and performance measures coupled with overtaking. The simulations included two types of driving scenario in which one was urban and the other was rural. The main results show no effect of this head-movement produced motion parallax on sense of presence, head movement, time to collision, distance judgment, or speed judgment.However, the results show an effect on lateral positioning. When initiating the overtaking maneuver there is a lateral positioning farther away from the road center as effect of the motion parallax in both types of scenario, which can be interpreted as indicating use of naturally occurring information that change behavior at overtaking. Nevertheless, only showing tendencies of effects, absent is any clear additional impact of this motion parallax in the simulated driving.
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| 4. |
- Rudmark, Daniel, et al.
(författare)
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Lessons from the Regulation of E-scooters through the MDS Standard: Policy Lessons for Connected Vehicles
- 2023
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Ingår i: Proceedings of the 56th Hawaii International Conference on System Sciences. - : IEEE. - 9780998133164
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Konferensbidrag (refereegranskat)abstract
- Connected vehicles generate new data streams that present promising opportunities for policymakers to monitor and learn from events and behavior. To explore what we can learn from how public entities leverage ubiquitous data streams for policy development and enforcement, we draw on a case study of the standard Mobility Data Specification (MDS) and its use by cities to regulate E-scooter operators. Our findings suggest that (1) the richness of real-time data changes the speed of policy revision, (2) data access enables moving some micro-decisions to the edge, and (3) policy will be formulated as fixed or flexible with different amendment rules.
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| 5. |
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| 6. |
- Forsblad, Mattias, 1985-, et al.
(författare)
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How Children with Mild Intellectual Disability Experience Self-driving Buses : In Support of Agency
- 2023
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Ingår i: Transaction on Transport Sciences. - : Palacky University Olomouc. - 1802-971X .- 1802-9876. ; 14:2, s. 21-31
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Tidskriftsartikel (refereegranskat)abstract
- Many people with intellectual disability experience their needs and desires not being fully considered. Responding to this problem, the purpose of this study is to investigate how children with mild intellectual disability experience self-driving buses. On each bus, a person called "safety driver" monitors the ride and takes control if a problematic situation arises. The purpose is also to investigate what roles support persons and safety drivers play. In addition, the research aims to propose improvements in how the design of these self-driving buses can better motivate children with intellectual disability to use them in support of their agency. To address this, we arranged and studied seven rides on self-driving buses, for 16 children diagnosed to have mild intellectual disability, and their support persons. Interviews with the children were held after the rides, and both the rides and interviews were video recorded.The analysis was in part inductive but also employed a theory based on motivation: self-determination theory. For several children, the bus worked as a vehicle for a social sightseeing tour of the local environment, and the current design did not hinder such an experience. Overall, many of the children had a positive experience, but there is room for improvement regarding the design of the buses. Some children expressed curiosity and a few frustrations with how the bus behaved in traffic. For instance, it was difficult for the children to understand why the bus braked for things that were hard for them to perceive. From observation, it appears that the accompanying support person and safety driver played an important role in making children safe and shaping the social environment on the bus. The support persons were also essential for some children to ride the bus at all. The safety driver provided the children with information about how the bus worked. Both the safety driver and the support person had a positive impact on the children's experience.
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| 7. |
- Persson, Anna, et al.
(författare)
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Heart Rate Variability for Classification of Alert Versus Sleep Deprived Drivers in Real Road Driving Conditions
- 2021
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - : IEEE. - 1524-9050 .- 1558-0016. ; 22:6, s. 3316-3325
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Tidskriftsartikel (refereegranskat)abstract
- Driver sleepiness is a contributing factor in many road fatalities. A long-standing goal in driver state research has therefore been to develop a robust sleepiness detection system. It has been suggested that various heart rate variability (HRV) metrics can be used for driver sleepiness classification. However, since heart rate is modulated not only by sleepiness but also by several other time-varying intra-individual factors such as posture, distress, boredom and relaxation, it is relevant to highlight not only the possibilities but also the difficulties involved in HRV-based driver sleepiness classification. This paper investigates the reliability of HRV as a standalone feature for driver sleepiness detection in a realistic setting. Data from three real-road driving studies were used, including 86 drivers in both alert and sleep-deprived conditions. Subjective ratings based on the Karolinska sleepiness scale (KSS) were used as ground truth when training four binary classifiers (k-nearest neighbours, support vector machine, AdaBoost, and random forest). The best performance was achieved with the random forest classifier with an accuracy of 85%. However, the accuracy dropped to 64% for three-class classification and to 44% for subject-independent, leave-one-participant-out classification. The worst results were obtained in the severely sleepy class. The results show that in realistic driving conditions, subject-independent sleepiness classification based on HRV is poor. The conclusion is that more work is needed to control for the many confounding factors that also influence HRV before it can be used as input to a driver sleepiness detection system.
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| 8. |
- Persson, Anna, et al.
(författare)
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Heart Rate Variability for Driver Sleepiness Classification in Real Road Driving Conditions
- 2019
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - : IEEE. - 9781538613115 - 9781538613122 ; , s. 6537-6540
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Konferensbidrag (refereegranskat)abstract
- Approximately 20-30% of all road fatalities are related to driver sleepiness. A long-lasting goal in driver state research has therefore been to develop a robust sleepiness detection system. Since the alertness level is reflected in autonomous nervous system activity, it has been suggested that various heart rate variability (HRV) metrics can be used as features for driver sleepiness classification. Since the heart rate is modulated by many different factors, and not just by sleepiness, it is relevant to question the high driver sleepiness classification accuracies that have occasionally been presented in the literature. The main objective of this paper is thus to test how well a sleepiness classification system based on HRV features really is. A unique data set with 86 drivers, obtained while driving on real roads in real traffic, both in alert and sleep deprived conditions, was used to train and test a support vector machine (SVM) classifier. Subjective ratings based on the Karolinska sleepiness scale (KSS) was used as ground truth to divide the data into three classes (alert, somewhat sleepy and severely sleepy). Even though nearly all the 24 investigated HRV metrics showed significant differences between sleepiness levels, the SVM results only reached a mean accuracy of 61 %, with the worst results originating from the severely sleepy cases. In summary, the high classification performance that may arise in studies with high experimental control could not be replicated under realistic driving conditions. Future works should focus on how various confounding factors should be accounted for when using HRV based metrics as input to a driver sleepiness detection system.
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| 9. |
- Jonsson, Bertil, et al.
(författare)
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BioRID II manikin and human seating position in relation to car head restraint
- 2008
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Ingår i: International Journal of Crashworthiness. - Abingdon : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 13:5, s. 479-485
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the study was to compare stature, weight and backset (the horizontal distance (x) between the back of the occupant’s head and the front of the seam on top of the head restraint) of the Biofidelic Rear Impact Dummy (BioRID II) to the same variables on seated volunteers in a car. The following methods were used. Data were collected from 154 randomly selected Swedish individuals (78 males and 76 females). The volunteers and the BioRID II were examined in a Volvo V70 car, year model 2003, in three positions: driver (hands on steering wheel), front passenger (hands in lap) and rear passenger. The study results were as follows: the BioRID II was found to correspond approximately to a 35th-45th percentile male in stature (-2 cm), a 35th percentile male in weight (-7 kg), a 96th percentile female in stature (+11 cm) and a 69th percentile female in weight (+8 kg). The BioRID II was designed to represent a male driver. The BioRID II backset corresponded well with the average of the male drivers of its stature. Larger deviations in backset were found for other volunteer sizes and other seating positions. The average backsets were 26 mm for females and 63 mm for males in the front seat positions. The volunteers had larger backset in the driver position (60 mm) than in the front passenger position (29 mm). Smaller differences in backset were seen between the BioRID II and the volunteers in the rear passenger position. This study provides data regarding the occupant size coverage of BioRID II, and unique data regarding backset, of different occupant positions in the car; driver with hands on steering wheel, and front and rear passengers with hands in lap, for female and male in relation to the BioRID II dummy. © 2008 Taylor & Francis.
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| 10. |
- Antonson, Hans, 1963-, et al.
(författare)
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Road Salt Damage to Historical Milestones Indicates Adaptation of Winter Roads to Future Climate Change May Damage Arctic Cultural Heritage
- 2021
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Ingår i: Climate. - Basel : MDPI. - 2225-1154. ; 9:10
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Tidskriftsartikel (refereegranskat)abstract
- There is no doubt that anthropogenic global warming is accelerating damage to cultural heritage. Adaptation measures are required to reduce the loss of sites, monuments and remains. However, little research has been directed towards understanding potential impacts of climate adaptation measures in other governmental sectors on cultural heritage. We provide a case study demonstrating that winter road salt, used to reduce ice related accidents, damages historical iron milestones. As the climate warms, road salt use will move north into areas where sites have been protected by contiguous winter snow cover. This will expose Artic/sub-Arctic cultural heritage, including Viking graves and Sami sites, to a new anthropogenic source of damage. Research and planning should therefore include the evaluation of secondary impacts when choosing climate adaptation strategies.
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