| 1. |
- Andersson, Anders, 1983-
(författare)
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Distributed Moving Base Driving Simulators : Technology, Performance, and Requirements
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Development of new functionality and smart systems for different types of vehicles is accelerating with the advent of new emerging technologies such as connected and autonomous vehicles. To ensure that these new systems and functions work as intended, flexible and credible evaluation tools are necessary. One example of this type of tool is a driving simulator, which can be used for testing new and existing vehicle concepts and driver support systems. When a driver in a driving simulator operates it in the same way as they would in actual traffic, you get a realistic evaluation of what you want to investigate. Two advantages of a driving simulator are (1.) that you can repeat the same situation several times over a short period of time, and (2.) you can study driver reactions during dangerous situations that could result in serious injuries if they occurred in the real world. An important component of a driving simulator is the vehicle model, i.e., the model that describes how the vehicle reacts to its surroundings and driver inputs. To increase the simulator realism or the computational performance, it is possible to divide the vehicle model into subsystems that run on different computers that are connected in a network. A subsystem can also be replaced with hardware using so-called hardware-in-the-loop simulation, and can then be connected to the rest of the vehicle model using a specified interface. The technique of dividing a model into smaller subsystems running on separate nodes that communicate through a network is called distributed simulation.This thesis investigates if and how a distributed simulator design might facilitate the maintenance and new development required for a driving simulator to be able to keep up with the increasing pace of vehicle development. For this purpose, three different distributed simulator solutions have been designed, built, and analyzed with the aim of constructing distributed simulators, including external hardware, where the simulation achieves the same degree of realism as with a traditional driving simulator. One of these simulator solutions has been used to create a parameterized powertrain model that can be configured to represent any of a number of different vehicles. Furthermore, the driver's driving task is combined with the powertrain model to monitor deviations. After the powertrain model was created, subsystems from a simulator solution and the powertrain model have been transferred to a Modelica environment. The goal is to create a framework for requirement testing that guarantees sufficient realism, also for a distributed driving simulation.The results show that the distributed simulators we have developed work well overall with satisfactory performance. It is important to manage the vehicle model and how it is connected to a distributed system. In the distributed driveline simulator setup, the network delays were so small that they could be ignored, i.e., they did not affect the driving experience. However, if one gradually increases the delays, a driver in the distributed simulator will change his/her behavior. The impact of communication latency on a distributed simulator also depends on the simulator application, where different usages of the simulator, i.e., different simulator studies, will have different demands. We believe that many simulator studies could be performed using a distributed setup. One issue is how modifications to the system affect the vehicle model and the desired behavior. This leads to the need for methodology for managing model requirements. In order to detect model deviations in the simulator environment, a monitoring aid has been implemented to help notify test managers when a model behaves strangely or is driven outside of its validated region. Since the availability of distributed laboratory equipment can be limited, the possibility of using Modelica (which is an equation-based and object-oriented programming language) for simulating subsystems is also examined. Implementation of the model in Modelica has also been extended with requirements management, and in this work a framework is proposed for automatically evaluating the model in a tool.
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| 2. |
- Aramrattana, Maytheewat, et al.
(författare)
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A simulation framework for cooperative intelligent transport systems testing and evaluation
- 2017
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Ingår i: Transportation Research Part F. - Kidlington : Pergamon Press. - 1369-8478 .- 1873-5517.
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Tidskriftsartikel (refereegranskat)abstract
- Connected and automated driving in the context of cooperative intelligent transport systems (C-ITS) is an emerging area in transport systems research. Interaction and cooperation between actors in transport systems are now enabled by the connectivity by means of vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. To ensure the goals of C-ITS, which are safer and more efficient transport systems, testing and evaluation are required before deployment of C-ITS applications. Therefore, this paper presents a simulation framework—consisting of driving-, traffic-, and network-simulators—for testing and evaluation of C-ITS applications. Examples of cooperative adaptive cruise control (CACC) applications are presented, and are used as test cases for the simulation framework as well as to elaborate on potential use cases of it. Challenges from combining the simulators into one framework, and limitations are reported and discussed. Finally, the paper concludes with future development directions, and applications of the simulation framework in testing and evaluation of C-ITS. © 2017 Elsevier Ltd. All rights reserved.
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| 3. |
- Aramrattana, Maytheewat, et al.
(författare)
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Cooperative Driving Simulation
- 2016
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Ingår i: Proceedings of the Driving Simulation Conference 2016. ; , s. 123-132
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Konferensbidrag (refereegranskat)abstract
- For a few decades, driving simulators have been supporting research and development of advanced driver assistance systems (ADAS). In the near future, connected vehicles are expected to be deployed. Driving simulators will need to support evaluation of cooperative driving applications within cooperative intelligent transportation systems (C-ITS) scenarios. C-ITS utilize vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. Simulation of the inter vehicle communication is often not supported in driving simulators. On the other hand, previous efforts have been made to connect network simulators and traffic simulators, to perform C-ITS simulations. Nevertheless, interactions between actors in the system is an essential aspect of C-ITS. Driving simulators can provide the opportunity to study interactions and reactions of human drivers to the system. This paper present simulation of a C-ITS scenario using a combination of driving, network, and traffic simulators. The architecture of the solution and important challenges of the integration are presented. A scenario from Grand Cooperative Driving Challenge (GCDC) 2016 is implemented in the simulator as an example use case. Lastly, potential usages and future developments are discussed.
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| 4. |
- Aramrattana, Maytheewat, et al.
(författare)
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Evaluating Model Mismatch Impacting CACC Controllers in Mixed
- 2018
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Ingår i: IEEE Intelligent Vehicles Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538644522 - 9781538644515 - 9781538644539 ; , s. 1867-1872
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Konferensbidrag (refereegranskat)abstract
- At early market penetration, automated vehicles will share the road with legacy vehicles. For a safe transportation system, automated vehicle controllers therefore need to estimate the behavior of the legacy vehicles. However, mismatches between the estimated and real human behaviors can lead to inefficient control inputs, and even collisions in the worst case. In this paper, we propose a framework for evaluating the impact of model mismatch by interfacing a controller under test with a driving simulator. As a proof- of-concept, an algorithm based on Model Predictive Control (MPC) is evaluated in a braking scenario. We show how model mismatch between estimated and real human behavior can lead to a decrease in avoided collisions by almost 46%, and an increase in discomfort by almost 91%. Model mismatch is therefore non-negligible and the proposed framework is a unique method to evaluate them.
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| 5. |
- Aramrattana, Maytheewat
(författare)
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Modelling and Simulation for Evaluation of Cooperative Intelligent Transport System Functions
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Future vehicles are expected to be equipped with wireless communication technology, that enables them to be “connected” to each others and road infrastructures. Complementing current autonomous vehicles and automated driving systems, the wireless communication allows the vehicles to interact, cooperate, and be aware of its surroundings beyond their own sensors’ range. Such sys- tems are often referred to as Cooperative Intelligent Transport Systems (C-ITS), which aims to provide extra safety, efficiency, and sustainability to transporta- tion systems. Several C-ITS applications are under development and will require thorough testing and evaluation before their deployment in the real-world. C- ITS depend on several sub-systems, which increase their complexity, and makes them difficult to evaluate.Simulations are often used to evaluate many different automotive applications, including C-ITS. Although they have been used extensively, simulation tools dedicated to determine all aspects of C-ITS are rare, especially human factors aspects, which are often ignored. The majority of the simulation tools for C-ITS rely heavily on different combinations of network and traffic simulators. The human factors issues have been covered in only a few C-ITS simulation tools, that involve a driving simulator. Therefore, in this thesis, a C-ITS simulation framework that combines driving, network, and traffic simulators is presented. The simulation framework is able to evaluate C-ITS applications from three perspectives; a) human driver; b) wireless communication; and c) traffic systems.Cooperative Adaptive Cruise Control (CACC) and its applications are chosen as the first set of C-ITS functions to be evaluated. Example scenarios from CACC and platoon merging applications are presented, and used as test cases for the simulation framework, as well as to elaborate potential usages of it. Moreover, approaches, results, and challenges from composing the simulation framework are presented and discussed. The results shows the usefulness of the proposed simulation framework.
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| 6. |
- Aramrattana, Maytheewat, et al.
(författare)
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Safety Analysis of Cooperative Adaptive Cruise Control in Vehicle Cut-in Situations
- 2017
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Ingår i: Proceedings of 2017 4th International Symposium on Future Active Safety Technology towards Zero-Traffic-Accidents (FAST-zero). - : Society of Automotive Engineers of Japan.
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Konferensbidrag (refereegranskat)abstract
- Cooperative adaptive cruise control (CACC) is a cooperative intelligent transport systems (C-ITS) function, which especially when used in platooning applications, possess many expected benefits including efficient road space utilization and reduced fuel consumption. Cut-in manoeuvres in platoons can potentially reduce those benefits, and are not desired from a safety point of view. Unfortunately, in realistic traffic scenarios, cut-in manoeuvres can be expected, especially from non-connected vehicles. In this paper two different controllers for platooning are explored, aiming at maintaining the safety of the platoon while a vehicle is cutting in from the adjacent lane. A realistic scenario, where a human driver performs the cut-in manoeuvre is used to demonstrate the effectiveness of the controllers. Safety analysis of CACC controllers using time to collision (TTC) under such situation is presented. The analysis using TTC indicate that, although potential risks are always high in CACC applications such as platooning due to the small inter-vehicular distances, dangerous TTC (TTC < 6 seconds) is not frequent. Future research directions are also discussed along with the results.
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| 7. |
- Aramrattana, Maytheewat, 1988-, et al.
(författare)
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Simulation of cut-in by manually driven vehicles in platooning scenarios
- 2017
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Ingår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC. - Piscataway, NJ : IEEE. - 9781538615256 - 9781538615263 - 9781538615270
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Konferensbidrag (refereegranskat)abstract
- In the near future, Cooperative Intelligent Transport System (C-ITS) applications are expected to be deployed. To support this, simulation is often used to design and evaluate the applications during the early development phases. Simulations of C-ITS scenarios often assume a fleet of homogeneous vehicles within the transportation system. In contrast, once C-ITS is deployed, the traffic scenarios will consist of a mixture of connected and non-connected vehicles, which, in addition, can be driven manually or automatically. Such mixed cases are rarely analysed, especially those where manually driven vehicles are involved. Therefore, this paper presents a C-ITS simulation framework, which incorporates a manually driven car through a driving simulator interacting with a traffic simulator, and a communication simulator, which together enable modelling and analysis of C-ITS applications and scenarios. Furthermore, example usages in the scenarios, where a manually driven vehicle cut-in to a platoon of Cooperative Adaptive Cruise Control (CACC) equipped vehicles are presented.
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| 8. |
- Chen, Lin, 1990, et al.
(författare)
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Effect of Al-distribution on oxygen activation over Cu-CHA
- 2018
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Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 8:8, s. 2131-2136
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Tidskriftsartikel (refereegranskat)abstract
- Cu(NH 3 ) 2 + -pairs in chabazite (CHA) have been suggested to activate oxygen during lowerature selective catalytic reduction of nitrogen oxides with ammonia (NH 3 -SCR). As charge neutrality requires that each Cu-complex is associated with a framework Al, the Al-distribution may affect Cu(NH 3 ) 2 + -pair formation and subsequent oxygen activation. Here, density functional theory calculations in combination with ab initio molecular dynamics simulations are used to explore Cu(NH 3 ) 2 + -pair formation and oxygen activation in Cu-CHA. The Al-distribution is found to markedly affect the probability for Cu(NH 3 ) 2 + -pair formation. Moreover, the molecular dynamics simulations reveal a low-energy reaction path for O 2 activation and dissociation. The facile O 2 dissociation suggests that Cu-pair formation rather than O 2 activation governs the lowerature NH 3 -SCR activity. The results indicate that precise synthesis of Cu-exchanged chabazite with respect to Al-distribution may enhance the catalytic activity.
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| 9. |
- Jansson, Johan, 1973-, et al.
(författare)
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Commitment to Sustainability in Small and Medium-Sized Enterprises : The Influence of Strategic Orientations and Management Values
- 2017
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Ingår i: Business Strategy and the Environment. - : John Wiley & Sons. - 0964-4733 .- 1099-0836. ; 26:1, s. 69-83
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Tidskriftsartikel (refereegranskat)abstract
- Ecosystem degradation and social sustainability have become important issues in the corporate sphere during the last few decades. However, research discussing corporate social responsibility and related concepts has often focused on larger companies, sometimes neglecting the specifics of small and medium-sized enterprises (SMEs). The main purpose of this study is to examine the relationships between two common strategic orientations, market orientation (MO) and entrepreneurial orientation (EO), in relation to sustainability commitment, sustainability practices and management values in SMEs. Questionnaire responses from 450 Swedish SMEs were analyzed, confirming the influence of MO, EO and sustainability practices on commitment to sustainability, implying that firms committed to sustainability see both market and entrepreneurial advantages of sustainability. The results also show that different parts of MO and EO differ in importance for commitment to sustainability among SMEs. Implications concern the importance for firms and policy makers to work with sustainability issues using both internal and external perspectives.
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| 10. |
- Jansson, Johan, 1973-, et al.
(författare)
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Vad talar för tåg på semesterresan?
- 2019
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Rapport (populärvet., debatt m.m.)abstract
- Fritidsresor svarar för drygt hälften av personresandet i Sverige mätt i kilometer. Huvuddelen av dessa resor (59 %) görs med bil, medan de kollektiva färdmedlen svarar för 10 %. Fritidsresorna är också längre än övriga resor, ca 51 km i genomsnitt. En överflyttning av i alla fall en del av fritidsresorna med bil till kollektiva färdmedel skulle ge märkbara effekter på koldioxidutsläpp, utsläpp av andra cancerogena ämnen samt trängsel i trafiken. I ett av Energimyndigheten finansierat projekt har vi undersökt hur olika åtgärder uppfattas av människor med olika transportresurser (tillgång till olika färdmedel och ekonomi) och transportbehov, vilka skillnader som finns mellan individer, och hur åtgärder kan utformas och presenteras för att upplevas som mer attraktiva. En del i projektet har riktats mot människors val av färdmedel vid semesterresor, och vilken roll tåg kan ha i detta val. Denna rapport handlar om just semesterresor, och hur människor värderar olika färdmedelsattribut vid längre resor.
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