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Sökning: WFRF:(Ljung Mikael)

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1.
  • Ljung, Efraim, et al. (författare)
  • Identifying And Developing Prerequisites For Takt Planning In A BIM-Based Construction Process
  • 2023
  • Ingår i: Managing the digital transformation of construction industry.
  • Konferensbidrag (refereegranskat)abstract
    • The construction industry is undergoing a significant shift in how design and production are conducted. Building Information Modeling (BIM) has emerged as a key tool for coordinating information from all involved disciplines and providing a more holistic view of the construction process. However, effective coordination and communication between different professions remain major challenges that require new approaches to project management. Takt planning has gained increasing attention as a potential solution to improve traditional planning methods. Despite this, there is a lack of real-world studies exploring BIM and takt planning where information is structured according to takt planning. A takt planning structure for all BIM-models would bring a more holistic understanding of what is to be done, controlled, and reported back. To address this gap, this paper presents findings from a three-stage research process. Firstly, form a focus group of disciplines to find a shared structure to present the execution in a common way for design and construction in a lab environment at a conceptual level, secondly implementing it to the detailed design information for real -world case project in workshops and group meetings with the focus group and then thirdly, evaluate it in the case project with the site staff involved. The findings highlight the importance of a shared denominator to get a holistic approach to project management and enabling takt planning throughout all phases of construction, providing insights into its practical application and benefits for the construction industry.
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2.
  • Viklund Tallgren, Mikael, 1983, et al. (författare)
  • Developing support for BIM-based takt time schedules for production control
  • 2022
  • Ingår i: Proceedings of the 22nd International Conference on Construction Applications of Virtual Reality (CONVR 2022). - 9780992716141 ; 22, s. 723-730
  • Konferensbidrag (refereegranskat)abstract
    • Cost and schedule overruns are a major issue in the construction industry and a variety of location and activity-based planning, and control methods are used to address these issues. Takt time planning (TTP) has recently gained increased attention in Scandinavia through its use of fixed durations, use of location as a resource and demand on trade-completion and control before moving to the next location. The desire is to create a stable pace of work for each trade through a sequence of locations. There are also challenges to accomplish and communicate takt time schedules. However, through a 4D based collaborative planning approach, communication of the plan and a better understanding of the project and its challenges in production is reached. Thus, this paper aims to explore the possible direct connection between BIM, TTP and collaborative planning. The paper starts with a review of current research and practices and then follows with the three cases of application of takt time in BIM projects in production to identifying challenges in practice. From this the paper then compares and analyzes the cases and the three cases. The conclusion is that an integration of takt time and BIM through a collaborative planning system is viable, and that such a system would enable a direct connection between the TTP and the model.
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3.
  • Ahlström, Christer, 1977-, et al. (författare)
  • Road Vehicle Automation and Its Effects on Fatigue, Sleep, Rest, and Recuperation
  • 2023. - 1
  • Ingår i: The Handbook of Fatigue Management in Transportation. - Boca Raton : CRC Press. - 9781003213154
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • Assisted and automated driving brings new challenges and opportunities when it comes to driver fatigue. With lower levels of vehicle automation, driver monotony and boredom in combination with demanding attentive monitoring leads to higher levels of fatigue, especially during the night when the sleep pressure is high. With higher levels of vehicle automation, when the driver is not required to continuously monitor the roadway and the automation system, task-related fatigue can be counteracted by engaging in non-driving-related activities. Finally, with the highest levels of vehicle automation, it may even become possible for drivers to sleep while on the move. Aside from making it possible for private car drivers to take strategic naps during a drive, this also opens up the possibility for more flexible, risk management-based, hour of service regulations for professional drivers. This chapter summarises the current state of the art on how assisted and piloted driving affects driver fatigue and how automation may facilitate recovery and recuperation from fatigue while on the move. It also covers how automated functions will impact driver monitoring systems and how new ways of counteracting driver fatigue may arise when automation is available.
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5.
  • Al-Saffar, Anas, 1969-, et al. (författare)
  • Parallel Changes in Harvey-Bradshaw Index, TNFα, and Intestinal Fatty Acid Binding Protein  in Response to Infliximab in Crohn’s Disease
  • 2017
  • Ingår i: Gastroenterology Research and Practice. - Egypt : Hindawi Publishing Corporation. - 1687-6121 .- 1687-630X. ; , s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • Intestinal fatty acid binding protein (I-FABP) indicates barrier integrity. Aims: determine if I-FABP is elevated in active Crohn's disease (CD) and if I-FABP parallels anti-TNF alpha antibody (infliximab) induced lowering of TNF alpha and Harvey-Bradshaw Index (HBI) as potential indicator of mucosal healing. I-FABP distribution along human gut was determined. Serum from 10 CD patients collected during first three consecutive infliximab treatments with matched pretreatment and follow-up samples one week after each treatment and corresponding HBI data were analyzed. I-FABP reference interval was established from 31 healthy subjects with normal gut permeability. I-FABP and TNF alpha were measured by ELISA; CRP was measured by nephelometry. Healthy tissue was used for I-FABP immunohistochemistry. Pretreatment CD patient TNF alpha was 1.6-fold higher than in-house reference interval, while I-FABP was 2.5-fold higher, which lowered at follow-ups. Combining all 30 infusion/follow-up pairs also revealed changes in I-FABP. HBI followed this pattern; CRP declined gradually. I-FABP was expressed in epithelium of stomach, jejunum, ileum, and colon, with the highest expression in jejunum and ileum. I-FABP is elevated in active CD with a magnitude comparable to TNF alpha. Parallel infliximab effects on TNF alpha, HBI, and I-FABP were found. I-FABP may be useful as an intestine selective prognostic marker in CD.
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6.
  • Andersson, Mike, et al. (författare)
  • Investigations on the possibilities of a MISiCFET sensor system for OBD and combustion control utilizing different catalytic gate materials
  • 2004
  • Ingår i: Topics in catalysis. - 1022-5528 .- 1572-9028. ; 30-31:1, s. 365-368
  • Tidskriftsartikel (refereegranskat)abstract
    • Different catalytic materials, like Pt and Ir, applied as gate contacts on metal insulator silicon carbide field effect transistors — MISiCFET—facilitate the manufacture of gas sensor devices with differences in selectivity, devices which due to the chemical stability and wide band gap of SiC are suitable for high temperature applications. The combination of such devices in a sensor system, utilizing multivariate analysis/modeling, have been tested and some promising results in respect of monitoring a few typical exhaust and flue gas constituents, in the future aiming at on board diagnostics (OBD) and combustion control, have been obtained.
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7.
  • Anund, Anna, 1964-, et al. (författare)
  • Night-time scenarios in simulators : a prestudy of needs, knowledge and possible solutions
  • 2016
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The study in this publication investigates the need and potential for night-time scenarios in driving simulators, determines how such night-time scenarios could be reproduced and identifies the objects most important to reproduce. Although on average 12 out of every 24 hours are dark and considering that most situations are more demanding for drivers in dark conditions, simulations of driving scenarios with different degrees of darkness are not common. The project work comprised a pre-study that involved an investigation of the need and potential of night-time scenarios with the help of input from different stakeholders, consolidation of what is known up to now through benchmarking and state of the art, and a review of available technical solutions. The objective was to identify pros and cons with existing solutions and aspects that are important to consider in order to reproduce the most important components in realistic night-time scenarios. Based on the results, six important use cases were identified and two of these (‘Driver fatigue’ and ‘Objects without light sources’) were studied in more detail. It was concluded that for night-time scenarios there is enough darkness in general in the simulator environment. The question is whether it is possible to create sufficient contrast for objects that are meant to be observable. For daytime scenarios, the light levels in the simulator are clearly unrealistically low and this limitation might even trigger unwanted sleepiness.
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10.
  • Brink, Mikael, et al. (författare)
  • Anti-citrullinated protein antibody specificities and pulmonary fibrosis in relation to genetic loci in early rheumatoid arthritis
  • 2022
  • Ingår i: Rheumatology. - : Oxford University Press. - 1462-0324 .- 1462-0332. ; 61:12, s. 4985-4990
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives Pulmonary manifestations in RA are common comorbidities, but the underlying mechanisms are largely unknown. The added value of a multiplex of ACPA and genetic risk markers was evaluated for the development of pulmonary fibrosis (PF) in an inception cohort. Methods A total of 1184 patients with early RA were consecutively included and followed prospectively from the index date until death or 31 December 2016. The presence of 21 ACPA fine specificities was analysed using a custom-made microarray chip (Thermo Fisher Scientific, Uppsala, Sweden). Three SNPs, previously found related to PF were evaluated, rs2609255 (FAM13A), rs111521887 (TOLLIP) and rs35705950 (MUC5B). ACPA and genetic data were available for 841 RA patients, of whom 50 developed radiologically defined PF. Results In unadjusted analyses, 11 ACPA specificities were associated with PF development. In multiple variable analyses, six ACPA specificities were associated with increased risk of PF: vimentin (Vim)60-75, fibrinogen (Fib)beta 62-78 (72), Fib alpha 621-635, Bla26, collagen (C)II359-369 and F4-CIT-R (P < 0.01 to P < 0.05). The number of ACPA specificities was also related to PF development (P < 0.05 crude and adjusted models). In multiple variable models respectively adjusted for each of the SNPs, the number of ACPA specificities (P < 0.05 in all models), anti-Vim60-75 (P < 0.05, in all models), anti-Fib beta 62-78 (72) (P < 0.001 to P < 0.05), anti-CII359-369 (P < 0.05 in all models) and anti-F4-CIT-R AQ4 (P < 0.01 to P < 0.05), anti-Fib alpha 621-635 (P < 0.05 in one) and anti-Bla26 (P < 0.05 in two) were significantly associated with PF development. Conclusion The development of PF in an inception cohort of RA patients was associated with both presence of certain ACPA and the number of ACPA specificities and risk genes.
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11.
  • Broström, Robert, et al. (författare)
  • Individual glance strategies and their effect on the NHTSA visual manual distraction test
  • 2016
  • Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 36, s. 83-91
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of this paper was to investigate how individual differences in glance strategy could impact the glance performance test defined in the NHTSA visual manual distraction guidelines. Better understanding of the test procedure could help development of new technology for safe driving. A custom in-vehicle information system was developed and assessed in a driving simulator by eighteen participants. The interfaces were designed according to recommendations in the NHTSA guidelines and contained manual radio-tuning tasks, sound settings tasks and six letter spelling tasks. Two of the six tested interfaces fully complied with the test. In addition, clear individual differences in glance strategy were found among the participants. Four individual glance strategies were identified. Two of these, long glancers and frequent glancers, highly affected the outcome of the compliance test. Participants belonging to the long glancers and the frequent glancers categories were identified as statistical outliers in many test cases. For example, if the individual values of these participants were replaced with sample mean, the number of complying interfaces would increase to five out of six, which is more in line with expectations for these interfaces. The results of this study show that individual variations in glance strategy exist. Also, these individual variations seem to have a non- negligible influence on the result when performance-testing of in-vehicle interfaces is done according to the NTHSA guidelines.
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12.
  • Castillo, Daniel, 1977-, et al. (författare)
  • Arbetsdelning i praktiken : Satsning på nya avlastande tjänster i Skövde kommun
  • 2017
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Arbetsmarknadsmodellen Breddad kompetensförsörjning i Skövde kommun syftar till att avlasta ordinarie kommunal personal och förbättra deras arbetssituation. Genom en ökad arbetsdelning övertar arbetslösa arbetsuppgifter som inte kräver någon formell kompetens, vilket gör att ordinarie personal kan fokusera på sitt kärnarbete.Detta forskningsprojekt har undersökt praktiska förutsättningar för arbetsdelning vid fyra kommunala enheter. Studien visar att det överlag behövs mer personal och att förutsättningarna för arbetsdelning skiljer sig mellan verksamheterna. Avlastningen har trots detta främjat verksamhetens kvalitet, personalens arbetstillfredsställelse och minskat stressen. En framtida utmaning är dock finansieringen av de nya tjänsterna.Daniel Castillo är fil. dr i sociologi och forskningsassistent Mikael Ljung är fil. master i sociologi, båda verksamma vid Förvaltningsakademin, Södertörns högskola.
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13.
  • Darbandi, Tayebeh (författare)
  • Development of flue gas treatment for small-scale boilers with a focus on particulate matters purification
  • 2022
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Small-scale boilers significantly contribute to particle matter (PM) emissions, which adversely affect health and global warming. According to World Health Organization, particulate matter was ranked as the fifth significant parameter in premature death in 2015. Based on the Clean airpolicy package, which was established in 2013 by the European Commission, it is aimed to mitigate the emission from the combustion of energy sources to half by 2030. In Europe, small-scale biofuel boilers and domestic heating systems release 25% of total particulate matter annually. Thus, finding an economical method for small-scale cleaning flue gas is necessary.This research aims to obtain an efficient system to clean the flue gas from a small-scale biomass boiler. For this purpose, a setup has been built at Luleå University. The setup consists of a boiler (20kW), three heat exchangers, and a generator. The flue gas from combustion, which heats the water in the boiler, flows through the absorber and generator. In the absorber (packed bed wet scrubber), the flue gas is in contact with an absorption solution, and at the same time, particulate matter is cleaned from the flue gas. The solution is passed through a filter and is purified. A part of the solution flows through the generator, absorbed water is evaporated, and concentrated solution returns to the absorber. During this study, the stability of the solution in particulate matter collection was tested in the long-term running of the system (8 months), which did not show any deterioration in the solution ability for particle collection. The system efficiency in particulate matter size D50 (0.8-10 μm) collection efficiency was 42%. Also, the heat recovery of the system was improved by 18%.The effect of different forces on particulate matter in a wet scrubber was simulated by Ansys Fluent 19. 2 under different operation conditions. The governing forces on the particulate matter were studied, and the results showed that the concentration gradient has the highest effect on the collection of particulate matter. The effect of concentration gradient is explained as diffusiophoresis phenomenon. On the other hand, the temperature gradient (thermophoresis) did not strongly affect particulate matter collection. The influence of diffusiophoresis and thermophoresis on different particulate matter (PM) sizes under different flue gas velocities, temperatures, and water vapor mass fractions were simulated. Results demonstrated that increasing the flue gas velocity and particle size reduces the particle collection efficiency. The simulation result was validated against previous empirical models.In the next step, the effect of operation conditions on the PM collection efficiency was investigated. Based on the simulation results, the effect of water vapor concentration gradient, temperature gradient, and various heights of packed bed material in the absorber was studied experimentally. The measurements demonstrated that the water vapor concentration gradient greatly affects system PM collection efficiency. To improve the system’s efficiency, it is suggested to keep the temperature of the solution as low as possible and the absorption solution concentration at the highest applicable concentration. The obtained results showed that the absorber with a fully packed bed material has a better performance in particle collection.The obtained data can be used to build an efficient setup to clean the particulate matter released by small-scale boilers and would be interesting for companies that want to develop further the technology to be commercial for the market.
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14.
  • Edwards, Kieron D., et al. (författare)
  • Circadian clock components control daily growth activities by modulating cytokinin levels and cell division-associated gene expression in Populus trees
  • 2018
  • Ingår i: Plant, Cell and Environment. - : John Wiley & Sons. - 0140-7791 .- 1365-3040. ; 41:6, s. 1468-1482
  • Tidskriftsartikel (refereegranskat)abstract
    • Trees are carbon dioxide sinks and major producers of terrestrial biomass with distinct seasonal growth patterns. Circadian clocks enable the coordination of physiological and biochemical temporal activities, optimally regulating multiple traits including growth. To dissect the clock's role in growth, we analysed Populus tremula x P. tremuloides trees with impaired clock function due to down-regulation of central clock components. late elongated hypocotyl (lhy-10) trees, in which expression of LHY1 and LHY2 is reduced by RNAi, have a short free-running period and show disrupted temporal regulation of gene expression and reduced growth, producing 30-40% less biomass than wild-type trees. Genes important in growth regulation were expressed with an earlier phase in lhy-10, and CYCLIN D3 expression was misaligned and arrhythmic. Levels of cytokinins were lower in lhy-10 trees, which also showed a change in the time of peak expression of genes associated with cell division and growth. However, auxin levels were not altered in lhy-10 trees, and the size of the lignification zone in the stem showed a relative increase. The reduced growth rate and anatomical features of lhy-10 trees were mainly caused by misregulation of cell division, which may have resulted from impaired clock function.
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15.
  • Engström, Johan A Skifs, 1973, et al. (författare)
  • Adaptive behavior in the simulator: Implications for active safety system evaluation
  • 2011
  • Ingår i: Handbook of Driving Simulation for Engineering, Medicine, and Psychology. - 9781420061017 ; , s. 41-1-41-16-
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • The Problem. Driving is, most of the time, a self-paced task where drivers proactively control the driving situation, based on their expectations of how things will develop in the near future. Crashes are typically associated with unexpected events where this type of proactive adaptation failed in one way or another. These types of scenarios are the main targets for active safety systems. In evaluation studies, drivers’ responses to expected events may be qualitatively different from responses to similar, but unexpected, events. Hence, creating artificial active safety evaluation scenarios that truly represent the targeted real-world scenarios is a difficult challenge. Role of Driving Simulators. Driving simulators offer great possibilities to test active safety systems with real drivers in specific target scenarios under tight experimental control. However, in simulator studies, experimental control generally has to be traded against realism. The objective of this chapter is to address some key problems related to driver expectancy and associated adaptive behavior in the context of simulator-based active safety system evaluation. Key Results of Driving Simulator Studies. The chapter briefly reviews common types of adaptive driver strategies found in the literature and proposes a general conceptual framework for describing adaptive driver behavior. Based on this framework, some key challenges in dealing with these types of issues in simulator studies are identified and potential solutions discussed. Scenarios and Dependent Variables. Key variables representing adaptive driver behavior include the selection of speed, headway, and lane position as well as the allocation of attention and effort. It will never be possible to create artificial simulator scenarios for active safety evaluation that perfectly match their real-world counterparts, but there are several means that could be used to reduce the discrepancy. Problems with expectancy and resulting adaptive behavior may at least be partly overcome by various means to “trick” drivers into critical situations, several of which are addressed in the chapter. Platform Specificity and Equipment Limitations. The issues discussed in this chapter should apply across all types of driving simulator platforms. However, some of the proposed methods for tricking drivers into critical situations may require specific simulator features, such as a motion base.
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16.
  • Engström, Johan A Skifs, 1973, et al. (författare)
  • Effects of working memory load and repeated scenario exposure on emergency braking performance
  • 2010
  • Ingår i: Human Factors. - : SAGE Publications. - 1547-8181 .- 0018-7208. ; 52:5, s. 551-559
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: The objective of the present study was to examine the effect of working memory load on drivers' responses to a suddenly braking lead vehicle and whether this effect (if any) is moderated by repeated scenario exposure. Background: Several experimental studies have found delayed braking responses to lead vehicle braking events during concurrent performance of nonvisual, working memory-loading tasks, such as hands-free phone conversation. However, the common use of repeated, and hence somewhat expected, braking events may undermine the generalizability of these results to naturalistic, unexpected, emergency braking scenarios. Method: A critical lead vehicle braking scenario was implemented in a fixed-based simulator. The effects of working memory load and repeated scenario exposure on braking performance were examined. Results: Brake response time was decomposed into accelerator pedal release time and accelerator-to-brake pedal movement time. Accelerator pedal release times were strongly reduced with repeated scenario exposure and were delayed by working memory load with a small but significant amount (178 ms). The two factors did not interact. There were no effects on accelerator-to-brake pedal movement time. Conclusion:The results suggest that effects of working memory load on response performance obtained from repeated critical lead vehicle braking scenarios may be validly generalized to real world unexpected events. Application: The results have important implications for the interpretation of braking performance in experimental settings, in particular in the context of safety-related evaluation of in-vehicle information and communication technologies. © 2010, Human Factors and Ergonomics Society.
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17.
  • Engström, Johanna, et al. (författare)
  • Comparison of fecal calprotectin and serum C-reactive protein in early prediction of outcome to infliximab induction therapy
  • 2019
  • Ingår i: Scandinavian Journal of Gastroenterology. - : TAYLOR & FRANCIS LTD. - 0036-5521 .- 1502-7708. ; 54:9, s. 1081-1088
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Fecal calprotectin (FC) and serum C-reactive protein (CRP) are biomarkers of disease activity in Crohn's disease (CD) and ulcerative colitis (UC). We assessed FC, CRP, Harvey-Bradshaw index (HBi), partial Mayo Clinic Scoring (pMCS) and a cytokine panel during infliximab induction to predict therapy outcome.Methods: FC, CRP and clinical indices were evaluated in 123 (76 CD, 47 UC) patients before infliximab induction and after 12 weeks. Responders were monitored 48 weeks for an 'incident' (dosage increase, shortened dosage interval, surgery). Cutoff values for FC and CRP were obtained using receiver-operating characteristics (ROC). Disease progression was analyzed with Kaplan-Meier survivals, log-rank test and logistic regression for combined biomarkers. Cytokines were analyzed with Luminex multiplexing system.Results: Following infliximab, FC and CRP declined (p < .0001) along with HBi for CD and pMCS for UC. Simultaneously, IL-6 and TNF-alpha decreased, while IL-10 increased. Optimal FC ROC cutoff was 221 mu g/g (sensitivity 66%, specificity 67%, AUC 0.71) and CRP ROC cutoff 2.1 mg/L (sensitivity 54%, specificity 60%, AUC 0.58). In CD, FC > 221 mu g/g (p < .0001), but not CRP > 2.1 mg/L predicted an 'incident'. However, combined FC and CRP also predicted an 'incident' (p < .042). In UC, both FC > 221 mu g/g (p < .0005) and CRP > 2.1 mg/L (p = .0334) predicted 'incident', as did combined biomarkers (p < .005).Conclusions: Clinical disease activity is reduced by treatment with infliximab. In CD, persistently high FC, but not CRP, predict a treatment 'incident', whereas in UC both high FC and high CRP predict 'incident'. Combined FC and CRP values also predict an 'incident'.
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18.
  • Engwall, Olov, et al. (författare)
  • Identification of low-engaged learners in robot-led second language conversations with adults
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • The main aim of this study is to investigate if verbal, vocal and facial information can be used to identify low-engaged second language learners in robot-led conversation practice. The experiments were performed on voice recordings and video data from 50 conversations, in which a robotic head talks with pairs of adult language learners using four different interaction strategies with varying robot-learner focus and initiative. It was found that these robot interaction strategies influenced learner activity and engagement. The verbal analysis indicated that learners with low activity rated the robot significantly lower on two out of four scales related to social competence. The acoustic vocal and video-based facial analysis, based on manual annotations or machine learning classification, both showed that learners with low engagement rated the robot’s social competencies consistently, and in several cases significantly, lower, and in addition rated the learning effectiveness lower. The agreement between manual and automatic identification of low-engaged learners based on voice recordings or face videos was further found to be adequate for future use. These experiments constitute a first step towards enabling adaption to learners’ activity and engagement through within- and between-strategy changes of the robot’s interaction with learners. 
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19.
  • Engwall, Olov, et al. (författare)
  • Identification of Low-engaged Learners in Robot-led Second Language Conversations with Adults
  • 2022
  • Ingår i: ACM Transactions on Human-Robot Interaction. - : Association for Computing Machinery (ACM). - 2573-9522. ; 11:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The main aim of this study is to investigate if verbal, vocal, and facial information can be used to identify low-engaged second language learners in robot-led conversation practice. The experiments were performed on voice recordings and video data from 50 conversations, in which a robotic head talks with pairs of adult language learners using four different interaction strategies with varying robot-learner focus and initiative. It was found that these robot interaction strategies influenced learner activity and engagement. The verbal analysis indicated that learners with low activity rated the robot significantly lower on two out of four scales related to social competence. The acoustic vocal and video-based facial analysis, based on manual annotations or machine learning classification, both showed that learners with low engagement rated the robot's social competencies consistently, and in several cases significantly, lower, and in addition rated the learning effectiveness lower. The agreement between manual and automatic identification of low-engaged learners based on voice recordings or face videos was further found to be adequate for future use. These experiments constitute a first step towards enabling adaption to learners' activity and engagement through within- and between-strategy changes of the robot's interaction with learners.
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20.
  • Fagerlind, Helen, 1975, et al. (författare)
  • Development of an In-depth European Accident Causation Database and the Driving Reliability and Error Analysis Method, DREAM 3.0
  • 2008
  • Ingår i: 3rd International Conference ESAR (Expert Symposium on Accident Research). - Hannover, Tyskland.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The SafetyNet project was formulated in part to address the need for safety oriented European road accident data. One of the main tasks included within the project was the development of a methodology for better understanding of accident causation together with the development of an associated database involving data obtained from on-scene or “nearly on-scene” accident investigations. Information from these investigations was complemented by data from follow-up interviews with crash participants to determine critical events and contributory factors to the accident occurrence. A method for classification of accident contributing factors, known as DREAM 3.0, was developed and tested in conjunction with the SafetyNet activities. Collection of data and case analysis for some 1 000 individual crashes have recently been completed and inserted into the database and therefore aggregation analyses of the data are now being undertaken. This paper describes the methodology development, an overview of the database and the initial aggregation analyses.
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21.
  • Fischer, Martin, et al. (författare)
  • SPASS : Strengthen Performance Active Safety Simulator
  • 2017
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The aim of the SPASS project was to evaluate early development/rapid prototyping of new driver assistance systems by utilizing an advanced driving simulator in combination with a vehicle electrical architecture (including sensors, actuators and HMI). As a case study, the project demonstrated a novel active safety function which was rather well penetrated at Volvo Car Corporation (VCC), i.e. VCC had reference vehicles up and running. The project used VTI’s advanced driving simulator (Sim IV) in Gothenburg to establish a simulator platform for evaluation of driver-system interaction. The objective was to understand the capability of Sim IV when studying active safety functions requiring interaction between road infrastructure, sensors, electrical architecture, actuators and Human-Machine Interaction, and to understand how useful Sim IV is during the ordinary concept development phase at vehicle manufacturers. Warning systems that act when the driver is on the way to unintentionally leave the lane are already available today. The next generation of systems will not only warn the driver but will actively contribute to the steering task. One such system is VCC’s eLKA (emergency lane keeping assistance). As part of the SPASS project a scenario which lead to triggering of the eLKA function was developed and tested. The scenario consisted of rural road driving where drivers were distracted by means of a visual distraction task (reading numbers from a screen, placed at a relative large down angle relative to the view of the forward roadway) and then poured across the median towards an oncoming vehicle by introducing an additional steering angle in the simulated vehicle. An integrated test environment for active safety functions has been developed and evaluated. VCC’s emergency lane keeping assistance system (eLKA) has been used as test case in the evaluation, and the functioning of the eLKA has been validated and approved by experts at VCC.
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22.
  • Haag, Tobias, et al. (författare)
  • Försurning och kalkning i Jönköpings län: verksamhetsberättelse 2007
  • 2008
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Trots att svavelnedfallet har minskat med två tredjedelar sedan slutet av 1980-talet är nedfallet av försurande ämnen fortfarande över gränsen för vad marken beräknas tåla på sikt. I markvatten, som mäts på fyra lokaler i länet, saknas tydliga tecken på bättre förhållanden.För att uppnå miljömålen ”Bara naturlig försurning” och ”Levande sjöar och vattendrag” samt målet om ”God ekologisk status” i EU:s vattendirektiv behöver kalkningen fortsätta många år framöver.Kalkningen i länet berör hälften av länets yta men har störst omfattning i de sydvästra delarna. Ett minskat anslag för kalkning från Naturvårdsverket medförde ett intensivt revideringsarbete av alla kalkplaner i länet. Under 2007 spreds 12 700 ton kalk vilket är en minskning med 15 % jämfört med året innan. Under de senaste tio åren har kalkningen minskat med totalt 20 %.Arbetet med biologisk återställning har under 2007 inriktats på att öppna fiskvägar i några av Vätterns tillflöden vilket kommer att förbättra situationen för bland annat Vätteröringen som påverkats negativt av försurningen. Även i Nissan har fiskvägarna förbättrats vilket gynnar ett genuint strömstationärt öringbestånd.Den vattenkemiska måluppfyllelsen har undersökts på 347 lokaler i länet. För drygt 80 % av vattendragens längd och i 97 % av den sjöyta som undersökts var målet uppfyllt. Den biologiska måluppfyllelsen har generellt varit lägre än den vattenkemiska vilket är normalt. Under 2007 har målsättningen varit uppnådd i 49 % av vattendragens längd och 22 % av sjöytan vilket motsvarar 29 % av andelen sjöar. Den dåliga måluppfyllelsen beror på att sjöarna som nätprovfiskades under 2007 ligger i sydvästra delen av länet och är sjöar där biologisk återställning planeras.Enligt Naturvårdsverkets nya riktlinjer för hur ekologisk status ska bedömas, är endast hälften av de riksinventerade sjöarna försurade jämfört med vad tidigare bedömningsgrunder visade. Försurningsbedömning ska göras med MAGIC-modellen som modellerar fram vilket pH-värde en sjö hade 1860. Är pH-värdet idag mer än 0,4 pHenheter lägre än på 1800-talet så bedöms sjön som försurad. MAGIC-biblioteket är ett webbverktyg där man kan man hitta sjöar som är lik den sjö man är intresserad av och på så sätt försurningsbedöma sjön.Brunifiering är ett nytt begrepp som börjat användas under senare år i samband med att vattenfärgen i sjöar och vattendrag diskuteras. I de 13 tidsseriesjöar som finns inom eller nära de kalkade områdena i länet har vattenkemin studerats närmare. Svavelhalten har minskat i sjöarna men varken pH eller alkaliniteten (vattnets förmåga att stå emot syror) har ökat i motsvarande grad. Det har däremot den bruna färgen gjort. De humusämnen som ger vattnet dess bruna färg innehåller svaga organiska syror. Tidigare, under perioden med stort försurande nedfall, har dessa bundits i marken och inte nått vattnet. Nu när försurningen har minskat i såväl mark som vatten frigörs dessa ämnen och når sjöarna, vilket bromsar återhämtningen.
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23.
  • Habibovic, Azra, 1982, et al. (författare)
  • Driver behavior in car-to-pedestrian incidents: An application of the Driving Reliability and Error Analysis Method (DREAM)
  • 2013
  • Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 50, s. 554-565
  • Tidskriftsartikel (refereegranskat)abstract
    • To develop relevant road safety countermeasures, it is necessary to first obtain an in-depth understanding of how and why safety-critical situations such as incidents, near-crashes, and crashes occur. Video-recordings from naturalistic driving studies provide detailed information on events and circumstances prior to such situations that is difficult to obtain from traditional crash investigations, at least when it comes to the observable driver behavior. This study analyzed causation in 90 video-recordings of car-to-pedestrian incidents captured by onboard cameras in a naturalistic driving study in Japan. The Driving Reliability and Error Analysis Method (DREAM) was modified and used to identify contributing factors and causation patterns in these incidents. Two main causation patterns were found. In intersections, drivers failed to recognize the presence of the conflict pedestrian due to visual obstructions and/or because their attention was allocated towards something other than the conflict pedestrian. In incidents away from intersections, this pattern reoccurred along with another pattern showing that pedestrians often behaved in unexpected ways. These patterns indicate that an interactive advanced driver assistance system (ADAS) able to redirect the driver's attention could have averted many of the intersection incidents, while autonomous systems may be needed away from intersections. Cooperative ADAS may be needed to address issues raised by visual obstructions.
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24.
  • Hellström, Per M., 1954-, et al. (författare)
  • Luminal Nitric Oxide and Plasma Nitrite/Nitrate As Predictors of Colectomy in Corticosteroid-Treated Acute Colitis
  • 2015
  • Ingår i: Gastroenterology. - Uppsala. - 0016-5085 .- 1528-0012. ; 148:4, suppl. 1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Nitric oxide (NO) is known to be up-regulated by the induction of induciblenitric oxide synthase (iNOS) in inflammatory conditions. NO gas can be used as a markerof inflammatory activity in hollow organs. In parallel, plasma nitrite + nitrate (NOx) canreflect the ongoing inflammatory activity. We analyzed rectal NO before and after threedays, as well as plasma NOx in patients on glucocorticosteroid (GC) therapy in hospitalizedpatients. The aim of the study was to evaluate the relationship of rectal luminal NO andcirculating plasma NOx in acute fulminant colitis to the outcome as therapeutic responseor colectomy.Methods: 50 patients with median age 41 (range 20-78) years were hospitalizeddue to acute fulminant colitis and received treatment with high-dose GCs. Luminal nitricoxide was analyzed with chemiluminescence before therapy onset of therapy with GC andon day 3 of treatment. NOx was measured by nitrite/nitrate colorimetric assay. NO levelsand plasma NOx were compared to clinical disease activity index and C-reactive protein(CRP).Results: 32 responded to GC treatment and 18 did not, resulting in colectomy.The responders had higher luminal NO than non-responders (day 1: 12525±2600, day 3:15590±4157 ppb) vs non-responders (day 1: 2874±1283, day 3: 1137±297 ppb) (p<0.0114).Using an optimal cut-off NO level of 2250 ppb, sensitivity and specificity was 86% and81% for colectomy (p<0.0001). The area under the curve was 0.88 and likelihood ratio4.8. Similarly, plasma NOx was higher in responders vs non-responders (day 1: 6.2±0.3 vs3.9±0.4 umol/L) (p<0.0001). Using plasma NOx, we found a corresponding cut-off at 5umol/L with sensitivity 87% and specificity 87%. The area under the curve was 0.88 andlikelihood ratio 6.7. Luminal NO was also correlated to plasma NOx (r=0.33, p=0.0205).In the responder group, CRP levels decreased (day 1: 22.31±2.95, day 3: 15.69±3.57mg/L), whereas among non-responders CRP levels increased (day 1: 45.83±11.10, day 3:76.35±16.96 mg/L) (p<0.0167). Kaplan-Meier analysis showed that patients with baselineNO levels lower than 2250 ppb were at a significantly higher risk of colectomy within onemonth from onset of GCS treatment (p<0.0001). Twelve out of 18 (67%) in patients withday 1 NO <2250 ppb were colectomized, the corresponding number of patients with NO>2250 ppb was 3 out of 32 (9%). In a similar manner, using plasma NOx <5 uml/L foranalysis, we found 13 (72%) to be colectomized, and with >5 umol/L only two (6%).Conclusion: NO and its oxidation product NOx are markers of inflammatory activity in thegut. However, with more intense inflammation and mucosal damage, the less NO is produced.Luminal NO as well as plasma NOx can be used as a sensitive biomarker to predict colectomyin the outcome of acute fulminant colitis
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25.
  • Hofstedt, Annika, et al. (författare)
  • Pilot data findings from the Gothenburg treatment for gaming disorder: a cognitive behavioral treatment manual
  • 2023
  • Ingår i: Frontiers in Psychiatry. - 1664-0640. ; 14
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Gaming disorder (GD) is a new diagnosis included in the latest edition of the International Classification of Disease -11. Recently conducted international studies suggest a prevalence rate close to 2% for GD, highlighting the need for effective treatments for this patient population. Internationally there are few studies investigating effective treatments specifically designed for this condition. In this pilot study, we wanted to test a newly developed method, the Gothenburg Treatment for Gaming Disorder (GOT-TO-GO) manual; a 15-week cognitive behavioral therapy treatment for GD.Method: This study utilized a single group design with pretest, post-test and a three- and six-month follow-up, with measures of severity of GD and mood. The participants (n = 28) were treatment-seeking adults with GD, aged 17 to 49 years.Results: The results show a statistically significant decrease in symptoms of GD after treatment. Hours of gaming per week also decreased concomitantly with a 100% increase in non-gaming leisure hours. The decrease in symptoms of GD was maintained at the 3-months follow-up after treatment. Correspondingly we saw a decrease in both depression and anxiety that also was upheld 3 months after treatment.Conclusion: As GD is a new diagnostic concept more research is needed, also taking psychiatric comorbidity into consideration, to arrive at evidence-based conclusions regarding effective treatments. Considering the promising results in this small pilot study with large behavioral changes and reduced symptoms of GD, upheld at least 3 months after treatment, a larger randomized controlled study is warranted.
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26.
  • Huang, Yu-Hsing, et al. (författare)
  • Accident Models for Modern Road Traffic : Changing Times Creates New Demands
  • 2004
  • Ingår i: Proceedings of the International Conference on Systems, Man and Cybernetics.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The purpose of this study is to develop accident models that can be applied to modern road traffic. Several criteria are proposed that a model suitable for the conditions of modern road traffic should fulfil. Four commonly applied general accident models are reviewed, and found to be inadequate in relation to the criteria. Also, the consequences of an underlying structural problem in all four model types, which is the result of regarding the human as a system component, are discussed. To remedy the discovered problems, it is argued that traffic safety should make use of the developments that have been made in the field of industrial safety. Several suggestions are proposed for how a new model could be developed, based on experiences from industrial safety.
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27.
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28.
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29.
  • Huang, Yu-Hsing, 1970-, et al. (författare)
  • Factors Influencing the Causation of Accidents and Incidents
  • 2004
  • Ingår i: Human Factors in Design. - The Netherlands : Shaker Publishing. - 9042302496 ; , s. 25-34
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • The goal of this study is to identify and explain the MTO-factors Man, Technology, Organisation affecting the origin and the course of road traffic accidents and incidents. Human factors issues are essential to understand properly the aetiology of road traffic accidents, and in particular the possible mismatch between humans and technology. The study works from the assumption that an effective reduction of accidents and incidents require a reduction of this mismatch, hence the need for identification and control of the factors that cause it. The methodology of this study is based on the principles of cognitive systems engineering, where the driver and hisher vehicle are seen as a joint cognitive system. To analyse the mismatch between the joint driver-vehicle system JDVS and its environment, a detailed description of the course of the accident is necessary. A special investigation team collects data from actual traffic accidents in the Gothenburg area during a six-month period, starting in the fall of 2003. In addition to studying accidents, another team will also collect data on incidents and near misses. The study of incidents can provide a broader perspective on risky driving and unsafe situations, and thereby complements the accident data. The study makes use of a Driver Reliability and Error Analysis Method DREAM, derived from the more generic Cognitive Reliability and Error Analysis Method CREAM. The method has been tailored for this project to uncover the main MTO factors in traffic accidents. The contribution of this study is to provide a model and a method for uncovering MTO factors in road traffic accidents. The method provides a base for system designers to understand in detail traffic accident aetiology, and from that basis to develop either new technology or redesign existing systems to minimise traffic accidents, for instance by preventing certain classes of initiating events form taking place.
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30.
  • Huang, Yu-Hsing, et al. (författare)
  • MTO Factors Contributing to Road Accidents at Intersections
  • 2004
  • Ingår i: Proceedings of the International Conference on Cognitive System Engineering in Process Control. ; , s. 166-173
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • At present, workin road traffic safety is expanding from injury prevention toinclude also accident prevention. For accident preventive measuresto be effective, knowledge is needed about common causal factorsthat contribute to the occurrence of accidents. This paper aimstowards identification of such common factors for a specific subsetof all road accidents, namely intersection accidents. The data usedfor the study consists of in-depth investigation material fromsixteen intersection accidents that have been investigated by amulti-disciplinary accident investigation team. Data analysis wasperformed using DREAM, a MTO based accident investigation method.The results indicate that cognitive bias, hidden information,inadequate design of traffic environment, and competing task arecommon contributing factors of intersection accidents. Also, thedistribution of factors for different collision path scenarios wasstudied, and several patterns in the distribution were discovered.These patterns were then compared to the results of another studywith a similar aim, but based on database statistics rather thatin-depth data. The conclusion of the comparison is that the DREAMmethod, in combination with in-depth accident data, provides adeeper and more detailed insight into how and why different factorscontribute to accidents, and these insights are well suited foraccident preventive work.
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31.
  • Högberg, Cecilia, et al. (författare)
  • Immunochemical faecal occult blood tests in primary care and the risk of delay in the diagnosis of colorectal cancer
  • 2013
  • Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 31:4, s. 209-214
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective. To evaluate the value, risks, and shortcomings of immunochemical faecal occult blood tests (iFOBTs) in the diagnosis of colorectal cancer (CRC) and adenomas with high-grade dysplasia (HGD) in patients initially presenting to primary care. Design. A retrospective population-based study. Setting and subjects. All 495 cases of CRC and adenomas with HGD diagnosed in the county of Jamtland, Sweden from 2005 to 2009. Results. Of 495 patients 323 (65%) initially presented to primary care. IFOBTs were performed in 215 of 323 (67%) patients. The sensitivity of iFOBT for CRC and adenomas with HGD was 88% (83% when patients with a history of rectal bleeding were excluded). Of 34 patients with anaemia found en passant, 10 had negative iFOBTs. Time to diagnosis was longer for patients with negative iFOBTs (p < 0.0005). Conclusion. IFOBT might be helpful in selecting which patients to refer for colonoscopy. However, iFOBT has a limited sensitivity as a diagnostic test for CRC and adenomas with HGD. Relying only on iFOBT for colonoscopy referral could delay diagnosis, especially for patients with anaemia found en passant.
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32.
  • Johansson, Jimmy, et al. (författare)
  • Revealing Structure in Visualizations of Dense 2D and 3D Parallel Coordinates
  • 2006
  • Ingår i: Information Visualization. - : SAGE Publications. - 1473-8716 .- 1473-8724. ; 5:2, s. 125-136
  • Tidskriftsartikel (refereegranskat)abstract
    • Parallel coordinates is a well-known technique used for visualization of multivariate data. When the size of the data sets increases the parallel coordinates display results in an image far too cluttered to perceive any structure. We tackle this problem by constructing high-precision textures to represent the data. By using transfer functions that operate on the high-precision textures, it is possible to highlight different aspects of the entire data set or clusters of the data. Our methods are implemented in both standard 2D parallel coordinates and 3D multi-relational parallel coordinates. Furthermore, when visualizing a larger number of clusters, a technique called 'feature animation' may be used as guidance by presenting various cluster statistics. A case study is also performed to illustrate the analysis process when analysing large multivariate data sets using our proposed techniques.
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33.
  • Johansson, Jimmy, et al. (författare)
  • Revealing Structure within Clustered Parallel Coordinates Displays
  • 2005
  • Ingår i: Proceedings of IEEE Symposium on Information Visualization, 23-25 Oct.. ; , s. 125-132
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In order to gain insight into multivariate data, complex structures must be analysed and understood. Parallel coordinates is an excellent tool for visualizing this type of data but has its limitations. This paper deals with one of its main limitations - how to visualize a large number of data items without hiding the inherent structure they constitute. We solve this problem by constructing clusters and using high precision textures to represent them. We also use transfer functions that operate on the high precision textures in order to highlight different aspects of the cluster characteristics. Providing predefined transfer functions as well as the support to draw customized transfer functions makes it possible to extract different aspects of the data. We also show how feature animation can be used as guidance when simultaneously analysing several clusters. This technique makes it possible to visually represent statistical information about clusters and thus guides the user, making the analysis process more efficient.
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34.
  • Jung, Ylva (författare)
  • Estimation of Inverse Models Applied to Power Amplifier Predistortion
  • 2013
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Mathematical models are commonly used in technical applications to describe the behavior of a system. These models can be estimated from data, which is known as system identification. Usually the models are used to calculate the output for a given input, but in this thesis, the estimation of inverse models is investigated. That is, we want to find a model that can be used to calculate the input for a given output. In this setup, the goal is to minimize the difference between the input and the output from the cascaded systems (system and inverse). A good model would be one that reconstructs the original input when used in series with the original system.Different methods for estimating a system inverse exist. The inverse model can be based on a forward model, or it can be estimated directly by reversing the use of input and output in the identification procedure. The models obtained using the different approaches capture different aspects of the system, and the choice of method can have a large impact. Here, it is shown in a small linear example that a direct estimation of the inverse can be advantageous, when the inverse is supposed to be used in cascade with the system to reconstruct the input.Inverse systems turn up in many different applications, such as sensor calibration and power amplifier (PA) predistortion. PAs used in communication devices can be nonlinear, and this causes interference in adjacent transmitting channels, which will be noise to anyone that transmits in these channels. Therefore, linearization of the amplifier is needed, and a prefilter is used, called a predistorter. In this thesis, the predistortion problem has been investigated for a type of PA, called outphasing power amplifier, where the input signal is decomposed into two branches that are amplified separately by highly efficient nonlinear amplifiers, and then recombined. If the decomposition and summation of the two parts are not perfect, nonlinear terms will be introduced in the output, and predistortion is needed.Here, a predistorter has been constructed based on a model of the PA. In a first method, the structure of the outphasing amplifier has been used to model the distortion, and from this model, a predistorter can be estimated. However, this involves solving two nonconvex optimization problems, and the risk of obtaining a suboptimal solution. Exploring the structure of the PA, the problem can be reformulated such that the PA modeling basically can be done by solving two least-squares (LS) problems, which are convex. In a second step, an analytical description of an ideal predistorter can be used to obtain a predistorter estimate. Another approach is to compute the predistorter without a PA model by estimating the inverse directly. The methods have been evaluated in simulations and in measurements, and it is shown that the predistortion improves the linearity of the overall power amplifier system.
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35.
  • Karlsson, MariAnne, 1956, et al. (författare)
  • D1.1. Integrated Framework. Deliverable to the MeBeSafe project
  • 2018
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The MeBeSafe project intends to develop, implement and validate interventions that direct road users (drivers and cyclists) towards safer behaviour in common traffic situations which carry an elevated risk. More specifically, the aim is to change habitual traffic behaviour using different nudging interventions, i.e. subconsciously pushing road users in a desired direction without being prohibitive against alternative choices of action. The project will also compare different ways of coaching and evaluate the effect of a combination of nudging and coaching. This deliverable, D1.1 Integrated Framework, describes the work completed within WP1 of the MeBeSafe project. Based on literature reviews, interviews with academic and non-academic experts, discussions and workshops, the deliverable: (i) describes the key characteristics of nudging and coaching respectively; (ii) presents a framework that integrates the two, taking into consideration (in particular) time and frequency; (iii) describes underlying theories and models of relevance for understanding road user behaviour; (iii) explains road user profiles or characteristics of relevance to consider in the design of the interventions (i.e., in WP2, WP3, and WP4), as well as the design and interpretation of the outcome of the field trials (in WP5); and (iv) presents design considerations, i.e. factors that should be observed when improving on the initial ideas and further develop the design of the nudging and coaching interventions. More detailed design guidelines must be developed as part of the work to be completed in WP2, WP3, and WP4.
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36.
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37.
  • Kircher, Katja, 1973-, et al. (författare)
  • Secondary Task Workload Test Bench – 2TB : final report
  • 2014
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The main aim of this study was to investigate a selection of commonly used performance indicators (PIs) that have been reported to be sensitive to distraction and workload. More specifically, the PIs were tested for their ability to differentiate between task modalities (visual, cognitive and haptic) and task difficulty (easy, medium and hard). It was investigated whether possible differences were constant across two traffic situations (with/without lead vehicle) and two driving simulators. The experiment was conducted in the VTI Driving Simulator III, an advanced moving-base simulator, and in the Volvo Car Corporation driving simulator, an advanced fixed-base simulator. Both simulators were equipped with Smart Eye Pro eye tracking systems. A visual, a cognitive and a haptic secondary task were chosen to test the ability of the PIs to distinguish between the tasks’ loading on different modalities. Some of the main results from the study were:There were only minor differences between the two simulators for driving behaviour as described by longitudinal PIs. There was no overall offset, and the main difference was that the visual task led to stronger speed reductions in the moving-base simulator, which influenced both the mean speed and the speeding index.Regarding lateral PIs, major differences between the two simulators were found, both as a general offset and for those factor combinations that include modality and task difficulty level.With the visual or the haptic task active, the drivers positioned themselves further to the left and the variation in lateral position was higher in the fixed-base simulator.The number of lane crossings did not differ considerably between the simulators, but the lane departure area was larger on average in the fixed-base simulator, again influenced by modality, with the largest lane departure areas for the visual task, and in the case of the fixed-base simulator for the haptic task as well.Most of the eye movement related PIs had a general offset between the simulators. The drivers in the fixed-base simulator accumulated more time with their eyes off the road, especially during the visual and the cognitive tasks, while the drivers in the moving-base simulator cast longer single glances at the display.
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38.
  • Kowalski, Stewart, et al. (författare)
  • Two Case Studies in Using Chatbots for Security Training
  • 2009
  • Ingår i: Education and Technology for a Better World incl CDRom version. - : Springer. - 9783901882357
  • Konferensbidrag (refereegranskat)abstract
    • This paper discusses the result of two case studies performed in a large international company to test the use of chatbots for internal security training. The first study targeted 26 end users in the company while the second study examined 80 security specialists. From a quantitative analytical perspective there does not appears to be any significant findings when chatbots are used for security training. However there does appear to be qualitative data that suggest that the attitudes of the respondents appear to be more positive to security when chatbots are used than with the current traditional e-learning security training courses at the company.
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39.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • A conceptual framework for requirement specification and evaluation of active safety functions
  • 2011
  • Ingår i: Theoretical Issues in Ergonomics Science. - : Informa UK Limited. - 1464-536X .- 1463-922X. ; 12:1, s. 44-65
  • Tidskriftsartikel (refereegranskat)abstract
    • Active safety functions intended to prevent vehicle crashes are becoming increasingly prominent in traffic safety. Successful evaluation of their effects needs to be based on a conceptual framework, i.e. agreed-upon concepts and principles for defining evaluation scenarios, performance metrics and pass/fail criteria. The aim of this paper is to suggest some initial ideas toward such a conceptual framework for active safety function evaluation, based on a central concept termed 'situational control'. Situational control represents the degree of control jointly exerted by a driver and a vehicle over the development of specific traffic situations. The proposed framework is intended to be applicable to the whole evaluation process, from 'translation' of accident data into evaluation scenarios and definition of evaluation hypotheses, to selection of performance metrics and criteria. It is also meant to be generic, i.e. applicable to driving simulator and test track experiments as well as field operational tests.
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40.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Accident investigations for active safety at CHALMERS - new demands require new methodologies
  • 2007
  • Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 45:10, s. 881-894
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to develop efficient active safety systems, knowledge about what causes traffic accidents is required. One way to gather such knowledge is through traffic accident investigations. For the needs of active safety, most current accident investigation methodologies do not provide a sufficiently detailed or theoretically anchored analysis. Therefore, new studies need to be carried out using new theoretical frameworks and analysis methods. At CHALMERS, a new methodology called driving reliability and error analysis method has been developed and tried out during recent years. The methodology, as described and exemplified, shows good promise of meeting the needs of active safety accident investigation projects. Results from studies using the methodology also imply consequences for how benefit estimation of new active safety systems should be carried out.
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41.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Causation patterns and data collection blind spots for fatal intersection accidents in Norway
  • 2010
  • Ingår i: 4:th International Conference ESAR - Expert Symposium on Accident Research, Hannover, Germany.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Norwegian fatal intersection accidents from the years 2005-2007 were analysed to identify any causation patternsamong their underlying contributing factors, and also to evaluate whether the data collection and documentation proceduresused by the Norwegian in-depth investigation teams produces the information necessary to perform causation patternanalysis. A total of 28 fatal accidents were analysed. Details on crash contributing factors for each driver in each crash werefirst coded using the Driving Reliability and Error Analysis Method (DREAM), and then aggregated based on whether thedriver was going straight or turning. Analysis results indicate that turning drivers to a large extent are faced with perceptiondifficulties and unexpected behaviour from the primary conflict vehicle, while at the same time trying to negotiate ademanding traffic situation. Drivers going straight on the other hand have less perception difficulties. Instead, their mainproblem is that they largely expect turning drivers to yield. When this assumption is violated, they are either slow to react ordo not react at all. Contributing factors often pointed to in literature, e.g. high speed, drugs and/or alcohol and inadequatedriver training, played a role in 12 of 28 accidents. While this confirms their prevalence, it also indicates that most driversend up in these situations due to combinations of less auspicious contributing factors.In terms of data collection and documentation, information on blunt end factors (those more distant in time/space, yetimportant for the development of events) was more limited than information on sharp end factors (those close in time/spaceto the crash). A possible explanation is that analysts may view some blunt end factors as event circumstances rather thancontributing factors in themselves, and therefore do not report them. There was also an asymmetry in terms of reportedobstructions to view due to signposts and vegetation. While frequently reported as contributing for turning drivers, they wererarely reported as contributing for their counterparts in the same accidents. This probably reflects an involuntary focus of theanalyst on identifying contributing factors for the driver legally held liable, while less attention is paid to the driver judgednot at fault. Since who to blame often is irrelevant from a countermeasure development point of view, this underlyinginvestigator mindset needs addressing to avoid future bias in crash investigation reports.
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42.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Close Calls on the Road : A Study of Drivers’ Near-misses
  • 2004
  • Ingår i: Proceedings of the 3rd International Conference on Traffic and Transportation Psychology.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Joining a longstanding tradition in the field of industrial accident prevention, traffic accident research has begun to extend the study of accidents and serious incidents to include also near-misses and unsafe conditions. As part of a Swedish project called FICA (FactorsInfluencing the Causation of Incidents and Accidents), a study has been conducted to investigate near-misses, with the aim of clarifying different types and frequencies, as well as possible causes at the blunt and sharp end. The near-miss study made use of an analysis method called Driving Reliability and Error Analysis Method. The purpose of the method is to uncover the main socio-technical MTO factors involved in scenarios leading to traffic accidents. The study resulted in valuable understanding of near-misses in traffic and their aetiology, suggestions for improvements of the analysis method, and a basis for further,more extensive, near-miss studies.
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43.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • D5.1 MeBeSafe - Trial Design
  • 2019
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The report describe the research design for the project MeBeSafe, where different nudges as well as coaching measures to behave more safely in traffic are tested.
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44.
  • Ljung Aust, Mikael, 1973 (författare)
  • Developing Theoretical and Empirical Definitions of Safety Problems in Driving Suitable for Active Safety Function Evaluation
  • 2009
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • In passive safety, the requirement specifications used for evaluation of protective functions are both standardised and specified at a high level of detail regarding evaluation scenario definition, performance metrics and pass/fail criteria. For active safety, while several propositions for evaluation scenarios have been made, neither these, nor performance metrics and pass/fail criteria have yet reached a similar level of detail and standardisation. The objective of this thesis is to address two underlying reasons for this difference. One is theoretical in nature. On a general level, a set of principles and concepts which capture the fundamental ideas of a field of science can be called a conceptual framework. For active safety function evaluation, such a framework is currently lacking. To address this issue, a conceptual framework called Situational control was developed. The framework integrates fundamental ideas relevant for active safety function evaluation into a holistic and practically applicable picture. Its applicability was demonstrated by applying it in the context of writing and implementing requirement specifications for active safety function evaluation.The second reason is of empirical character. To evaluate the extent to which active safety functions prevent and/or mitigate crashes, it is essential to characterize the sequence of events which leads to collisions in a way which includes information on causal factors. To do this, data from official databases (macroscopic data), and in-depth case studies is often used. Macroscopic data is usually statistically representative but has limited information on why crashes happen, while the opposite is true of case studies. Using the two in combination would therefore seem ideal. However, the principles for connecting them are far from clear and current approaches suffer inherent weaknesses. To address this issue, a generalization methodology which links information in case studies to macroscopic crash types, in a way which covers not only context but also causation similarity, was developed. The feasibility of the methodology was tested through application on three sets of intersection crash data. Results indicate that the methodology was sufficiently successful to warrant further exploration with larger data sets.
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45.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Effects of forward collision warning and repeated event exposure on emergency braking
  • 2013
  • Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 18, s. 34-46
  • Tidskriftsartikel (refereegranskat)abstract
    • Many experimental studies use repeated lead vehicle braking events to study the effects of forward collision warning (FCW) systems. It can, however, be argued that the use of repeated events induce expectancies and anticipatory behaviour that may undermine validity in terms of generalisability to real-world, naturalistic, emergency braking events. The main objective of the present study was to examine to what extent the effect of FCW on response performance is moderated by repeated exposure to a critical lead vehicle braking event. A further objective was to examine if these effects depended on event criticality, here defined as the available time headway when the lead vehicle starts to brake. A critical lead vehicle braking event was implemented in a moving-base simulator. The effects of FCW, repeated event exposure and initial time headway on driver response times and safety margins were examined. The results showed that the effect of FCW depended strongly on both repeated exposure and initial time headway. In particular, no effects of FCW were found for the first exposure, while strong effects occurred when the scenario was repeated. This was interpreted in terms of a switch from closed-loop responses triggered reactively by the situation, towards an open-loop strategy where subjects with FCW responded proactively directly to the warning. It was also found that initial time headway strongly determined response times in closed-loop conditions but not in open-loop conditions. These results raise a number of methodological issues pertaining to the design of experimental studies with the aim of evaluating the effects of active safety systems. In particular, the implementation of scenario exposure and criticality must be carefully considered.
  •  
46.
  • Ljung Aust, Mikael, et al. (författare)
  • Effects of forward collision warning, initial time headway and repeated scenario exposure on driver response in emergency lead vehicle braking scenarios
  • 2011
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • To address the research questions, acritical lead vehicle braking scenario and anFCW system was developed and pilot tested in Saab’s fixed based driving simulator in Trollhättan. After piloting, the scenario was implemented in VTI’s moving base simulatorin Linköping, and the effects,of FCW presence, two different initial time headways at visual distraction task onset and repeated scenario exposure, on driver response timeswere examined.The study showed significant effects of FCW and repeated scenario exposure on response times. Moreover, these effects were not additivei.e. a significant interaction between the two was found. There was also a significant effect on responsetimes ofinitial time headway at onset of the visual distraction task. In addition, an interaction between initial time headway and repeated scenario exposure was found for drivers with FCW, but not for drivers without FCW. A second objective of the project was to compare the extent to which the VTI moving base simulator with motion cues generates similar driver responses(quantitatively and qualitatively)as the static simulator set-up at Saab. In general, theresults from this project have important implications for the interpretation of driver performance in experimental settings, particularlywhen aiming toevaluate safety-related in-vehicle information and warning technologies. For onething,they pose a general question markaround the generalizabilityof results to real world events. Second, a future prerequisite for FCW studies should probably be that test drivers have a previous level of system exposure level which matchesthat of real world drivers encountering typical critical events. Also, tuning the initialtime headwayat distraction task onsetin the experimentalsetting to real world conditions is of critical importance.
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47.
  •  
48.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Fatal intersection crashes in Norway: Patterns in Contributing Factors and Data Collection Challenges
  • 2012
  • Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 45, s. 782-791
  • Tidskriftsartikel (refereegranskat)abstract
    • Fatal motor vehicle intersection crashes occurring in Norway in the years 2005–2007 were analyzed to identify causation patterns among their underlying contributing factors, and also to assess if the data collection and documentation procedures used by the Norwegian in-depth investigation teams produces the information necessary to do causation pattern analysis. 28 fatal accidents were analyzed. Causation charts of contributing factors were first coded for each driver in each crash using the Driving Reliability and Error Analysis Method (DREAM). Next, the charts were aggregated based on a combination of conflict types and whether the driver was going straight or turning. Analysis results indicate that drivers who were performing a turning maneuver in these crashes faced perception difficulties and unexpected behavior from the primary conflict vehicle, while at the same time trying to negotiate a demanding traffic situation. Drivers who were going straight on the other hand had less perception difficulties but largely expect anyturning drivers to yield, which led to either slow reaction or no reaction at all. In terms of common contributing factors, those often pointed to in literature as contributing to fatal crashes, e.g. high speed, drugs and/or alcohol and inadequate driver training, contributed in 12 of 28 accidents. This confirmstheir prevalence, but also shows that most drivers end up in these situations due to combinations of less auspicious contributing factors. In terms of data collection and documentation, there was an asymmetry in terms of reported obstructions to view due to signposts and vegetation. These were frequently reported as contributing for turning drivers, but rarely reported as contributing for their counterparts in the same crashes. This probably reflects an involuntary focus of the analyst on identifying contributing factors for the driver held legally liable, while less attention is paid to the driver judged not at fault. Since who toblame often is irrelevant from a countermeasure development point of view, this underlying investigator approach needs to be addressed to avoid future bias in crash investigation reports.
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49.
  • Ljung Aust, Mikael, 1973, et al. (författare)
  • Final measures (Deliverable 5.5)
  • 2020
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The main objective of WP5 has been to run a set of field trials with naïve users (i.e. not experts involved in the development of the measures) for all nudging and coaching measures developed in WP2-4. Then, given the outcome of the field trials, the task has been to analyse which impacts these measures may have on road safety along with the cost of implementing them in vehicle fleets and/or infrastructure. All these activities have taken place in Tasks 5.4 (Data collection) and 5.6 (Data analysis).
  •  
50.
  • Ljung Aust, Mikael, 1973 (författare)
  • Generalization of case studies in road traffic when defining pre-crash scenarios for active safety function evaluation
  • 2010
  • Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 42:4, s. 1172-1183
  • Tidskriftsartikel (refereegranskat)abstract
    • To define pre-crash scenarios for evaluation of active safety functions, data from crash investigations is often used. Typical data sources include official databases with police reported crashes (macroscopic data) and in-depth case studies (microscopic data). Macroscopic data is often representative but has little detail on causation, while the opposite is true of microscopic data. Combining the sources by coupling causation information from a set of case studies to a macroscopic crash type would therefore seem ideal. For the coupling to be valid however, it must be verified that the selected case study set is representative of the crash type. The aim of this study is to describe and test a new methodology for such verification by means of an intermediate layer of representatively sampled crash information (questionnaire responses from crash involved drivers). The methodology was applied to intersection crashes. For the data sets used, the similarity in crash causation for case studies and questionnaire crashes, together with the context similarity for questionnaire crashes and the macroscopic crash type, was sufficient to argue that the case studies were representative of the crash type. While results must be considered preliminary given the limited data sets used, the proposed methodology shows promise for future work related to defining pre-crash scenarios for ADAS evaluation. (C) 2010 Elsevier Ltd. All rights reserved.
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