| 1. |
- Kõljalg, Urmas, et al.
(författare)
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Towards a unified paradigm for sequence-based identification of fungi.
- 2013
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Ingår i: Molecular ecology. - : Wiley. - 1365-294X .- 0962-1083. ; 22:21, s. 5271-7
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term 'species hypothesis' (SH) for the taxa discovered in clustering on different similarity thresholds (97-99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.
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| 2. |
- Larsson, Marcus, 1979-, et al.
(författare)
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Curvature based Antenna Selection Method Evaluated Using the Data Age Metric and V2V Measurements
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop (ICCW). - Piscataway, NJ : IEEE Press. - 9781467363051 ; , s. 2356-2362
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Konferensbidrag (refereegranskat)abstract
- In this paper, we compare a method for selecting transmission antenna based on road curvature to a method based on periodically alternating between left and right hand side transmission antennas. Both methods aim to improve the success rate for communication between participants in a platoon of vehicles. Moreover, we propose the data age metric for online use as input to the algorithm controlling the inter-vehicle distance in platooning, e.g. to decide appropriate gap between the vehicles depending on the V2V communication quality. The methods have been evaluated through V2V communication measurements performed using heavy duty vehicles on public highway. We show that, when using the curvature-based method, a 150 ms data age deadline is only missed approximately half as often compared to when periodically alternating between left and right hand side transmission antennas. The methods have also been compared for different antenna combinations. © 2015 IEEE
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| 3. |
- Larsson, Marcus, 1979-
(författare)
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Methods to Improve V2V Communications in Platoons of Heavy Duty Vehicles
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the coming years V2V communications will probably be mandated and vehicle OEMs strive to find business opportunities to finance its investments in V2V communications technology. For heavy vehicles, platooning can be this business opportunity, with the motivation for the fleet owners that platooning can decrease the fuel consumption by up to 15 % when driving in platoons. However, challenges still exists with respect to the quality and reliability of the V2V communications, which is essential in order to enable platooning in a safe way.In this thesis, two proposals of improving the quality and reliability of V2V communications in a platooning scenario are presented. The first proposal is the Curvature Based Antenna Selection Method that utilize the curvature of the road in order to estimate which antenna have the highest probability of having line of sight conditions, hence highest probability of successful communication. The method assumes a platoon of heavy vehicles with one antenna mounted in each rear view mirror. It also assumes that the leading vehicle can estimate the yaw rate of the platoon in order to determine if it is turning or not. The second proposal include two message forwarding algorithms, the Reachability Matrix forwarding algorithm and the Data Age Dependent forwarding algorithm. Both algorithms utilize information on the preceding communication capability in order to estimate which node to choose as forwarding candidate. The Reachability Matrix Algorithm puts its focus on keeping the overhead low, while at the same time improve the information up-to-dateness. The Data Age Dependent algorithm instead puts its main focus on performance with respect to improving the information up-to-dateness, with the cost of higher overhead compared to the Reachability Matrix algorithm.Both proposals show potential of improving the quality of the V2V communication in a platooning scenario. The first proposal, the antenna selection method, is able to maintain a Data Age deadline of 150 ms approximately twice as often as when selecting transmission antenna in a round robin fashion. For the second proposal, the Reachability Matrix Algorithm reduces the miss of a 0.2 s Data Age deadline in the communication between the first and the fourth vehicle in a platoon from 18 % to 11 %, while only increasing the number of sent messages from 40 to 48.5 per second compared to when only broadcast is used. The Data Age Dependent algorithm shows even better performance with respect to reducing the missing of the 0.2 s Data Age deadline, i.e., with a reduction from 18 % to 5 %.
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| 4. |
- Allgayer, Rodrigo, et al.
(författare)
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Analysis of distributed control system using remote method invocation in wireless network
- 2011
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Ingår i: IECON 2011 Proceedings. - New York : IEEE. - 9781612849720 ; , s. 346-351
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Konferensbidrag (refereegranskat)abstract
- This work presents the temporal analysis for a distributed differential control system for a mobile robot deployed on a wireless network using the SunSPOT platform. The system is programmed in Java and each of its part is executed in a distinct processor which cooperates via a wireless network. The communication between the network nodes is made by remote procedure calls, which are implemented by a minimum version of the Java RMI (mRMI), presented in this work. Simulation results are compared to experimental data acquired by the deployment of the system on real devices, the SunSPOTs. The comparisons reveal that the distributed solution presents fairly good results besides the inserted errors due to the wireless communication. © 2011 IEEE.
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| 5. |
- Aramrattana, Maytheewat, 1988-, et al.
(författare)
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A Novel Risk Indicator for Cut-In Situations
- 2020
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Ingår i: 2020 IEEE 23rd International Conference on Intelligent Transportation Systems, ITSC 2020. - Piscataway, NJ : Institute of Electrical and Electronics Engineers Inc.. - 9781728141497 - 9781728141503
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Konferensbidrag (refereegranskat)abstract
- Cut-in situations occurs when a vehicle intentionally changes lane and ends up in front of another vehicle or in-between two vehicles. In such situations, having a method to indicate the collision risk prior to making the cut-in maneuver could potentially reduce the number of sideswipe and rear end collisions caused by the cut-in maneuvers. This paper propose a new risk indicator, namely cut-in risk indicator (CRI), as a way to indicate and potentially foresee collision risks in cut-in situations. As an example use case, we applied CRI on data from a driving simulation experiment involving a manually driven vehicle and an automated platoon in a highway merging situation. We then compared the results with time-to-collision (TTC), and suggest that CRI could correctly indicate collision risks in a more effective way. CRI can be computed on all vehicles involved in the cut-in situations, not only for the vehicle that is cutting in. Making it possible for other vehicles to estimate the collision risk, for example if a cut-in from another vehicle occurs, the surrounding vehicles could be warned and have the possibility to react in order to potentially avoid or mitigate accidents.
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| 6. |
- Aramrattana, Maytheewat, 1988-
(författare)
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A Simulation-Based Safety Analysis of CACC-Enabled Highway Platooning
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cooperative Intelligent Transport Systems (C-ITS) enable actors in the transport systems to interact and collaborate by exchanging information via wireless communication networks. There are several challenges to overcome before they can be implemented and deployed on public roads. Among the most important challenges are testing and evaluation in order to ensure the safety of C-ITS applications.This thesis focuses on testing and evaluation of C-ITS applications with regard to their safety using simulation. The main focus is on one C-ITS application, namely platooning, that is enabled by the Cooperative Adaptive Cruise Control (CACC) function. Therefore, this thesis considers two main topics: i) what should be modelled and simulated for testing and evaluation of C-ITS applications? and ii) how should CACC functions be evaluated in order to ensure safety?When C-ITS applications are deployed, we can expect traffic situations which consist of vehicles with different capabilities, in terms of automation and connectivity. We propose that involving human drivers in testing and evaluation is important in such mixed traffic situations. Considering important aspects of C-ITS including human drivers, we propose a simulation framework, which combines driving-, network-, and traffic simulators. The simulation framework has been validated by demonstrating several use cases in the scope of platooning. In particular, it is used to demonstrate and analyse the safety of platooning applications in cut-in situations, where a vehicle driven by a human driver cuts in between vehicles in platoon. To assess the situations, time-to-collision (TTC) and its extensions are used as safety indicators in the analyses.The simulation framework permits future C-ITS research in other fields such as human factors by involving human drivers in a C-ITS context. Results from the safety analyses show that cut-in situations are not always hazardous, and two factors that are the most highly correlated to the collisions are relative speed and distance between vehicles at the moment of cutting in. Moreover, we suggest that to solely rely on CACC functions is not sufficient to handle cut-in situations. Therefore, guidelines and standards are required to address these situations properly.
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| 7. |
- 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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| 8. |
- Aramrattana, Maytheewat, et al.
(författare)
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A Simulation Study on Effects of Platooning Gaps on Drivers of Conventional Vehicles in Highway Merging Situations
- 2021
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - Piscataway, NJ : Institute of Electrical and Electronics Engineers Inc.. - 1524-9050 .- 1558-0016.
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Tidskriftsartikel (refereegranskat)abstract
- Platooning refers to a group of vehicles that--enabled by wireless vehicle-to-vehicle (V2V) communication and vehicle automation--drives with short inter-vehicular distances. Before its deployment on public roads, several challenging traffic situations need to be handled. Among the challenges are cut-in situations, where a conventional vehicle--a vehicle that has no automation or V2V communication--changes lane and ends up between vehicles in a platoon. This paper presents results from a simulation study of a scenario, where a conventional vehicle, approaching from an on-ramp, merges into a platoon of five cars on a highway. We created the scenario with four platooning gaps: 15, 22.5, 30, and 42.5 meters. During the study, the conventional vehicle was driven by 37 test persons, who experienced all the platooning gaps using a driving simulator. The participants' opinions towards safety, comfort, and ease of driving between the platoon in each gap setting were also collected through a questionnaire. The results suggest that a 15-meter gap prevents most participants from cutting in, while causing potentially dangerous maneuvers and collisions when cut-in occurs. A platooning gap of at least 30 meters yield positive opinions from the participants, and facilitating more smooth cut-in maneuvers while less collisions were observed.
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| 9. |
- 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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| 10. |
- Aramrattana, Maytheewat, et al.
(författare)
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Dimensions of cooperative driving, ITS and automation
- 2015
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Ingår i: IEEE Intelligent Vehicles Symposium, Proceedings. - Piscataway, NJ : IEEE Press. - 9781467372664 ; , s. 144-149
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Konferensbidrag (refereegranskat)abstract
- Wireless technology supporting vehicle-to-vehicle (V2V), and vehicle-to-infrastructure (V2I) communication, allow vehicles and infrastructures to exchange information, and cooperate. Cooperation among the actors in an intelligent transport system (ITS) can introduce several benefits, for instance, increase safety, comfort, efficiency.Automation has also evolved in vehicle control and active safety functions. Combining cooperation and automation would enable more advanced functions such as automated highway merge and negotiating right-of-way in a cooperative intersection. However, the combination have influences on the structure of the overall transport systems as well as on its behaviour. In order to provide a common understanding of such systems, this paper presents an analysis of cooperative ITS (C-ITS) with regard to dimensions of cooperation. It also presents possible influence on driving behaviour and challenges in deployment and automation of C-ITS.
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