| 1. |
- Abbas, Taimoor, et al.
(författare)
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A Measurement Based Shadow Fading Model for Vehicle-to-Vehicle Network Simulations
- 2015
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Ingår i: International Journal of Antennas and Propagation. - : Hindawi Publishing Corporation. - 1687-5869 .- 1687-5877.
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Tidskriftsartikel (refereegranskat)abstract
- The vehicle-to-vehicle (V2V) propagation channel has significant implications on the design and performance of novel communication protocols for vehicular ad hoc networks (VANETs). Extensive research efforts have been made to develop V2V channel models to be implemented in advanced VANET system simulators for performance evaluation. The impact of shadowing caused by other vehicles has, however, largely been neglected in most of the models, as well as in the system simulations. In this paper we present a shadow fading model targeting system simulations based on real measurements performed in urban and highway scenarios. The measurement data is separated into three categories, line-of-sight (LOS), obstructed line-of-sight (OLOS) by vehicles, and non-line-of-sight due to buildings, with the help of video information recorded during the measurements. It is observed that vehicles obstructing the LOS induce an additional average attenuation of about 10 dB in the received signal power. An approach to incorporate the LOS/OLOS model into existing VANET simulators is also provided. Finally, system level VANET simulation results are presented, showing the difference between the LOS/OLOS model and a channel model based on Nakagami-m fading.
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| 2. |
- Baiocchi, Andrea, et al.
(författare)
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Age of Information in IEEE 802.11p
- 2021
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Ingår i: 2021 IFIP/IEEE International Symposium on Integrated Network Management (IM). - : IEEE. - 9783903176324 - 9781728190419 ; , s. 1024-1031
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Konferensbidrag (refereegranskat)abstract
- Vehicle-to-Everything (V2X) communication is essential for facilitating connected and automated driving, where vehicles and other road traffic participants share data instantaneously and cooperate to solve tricky traffic situations in milliseconds. This paper proposes two stochastic models for the V2X standard IEEE 802.11p to characterize amongst other things the Age of Information (AoI), a recently-proposed metric that measures the freshness of information. The first model is based on renewal process analysis of a tagged station with mean field approximation, while the second one adopts Markov chain approach with network level view. Analytical results show that IEEE 802.11p, given its adaptability to event-triggered and aperiodic messaging, supports advanced cooperative driving scenarios.
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| 3. |
- Belyaev, Evgeny, et al.
(författare)
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Live video streaming in IEEE 802.11p vehicular networks : Demonstration of an automotive surveillance application
- 2014
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Ingår i: Computer Communications Workshops (INFOCOM WKSHPS), 2014 IEEE Conference on. - Piscataway, United States : IEEE Press. - 9781479930883 ; , s. 131-132
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Konferensbidrag (refereegranskat)abstract
- Prospective IEEE 802.11p-enabled automotive video applications are identified. Preliminary experimental results of inter-vehicular live video streaming for surveillance applications are presented. A test-bed for the demonstration of the achievable visual quality under different channel conditions is described.
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| 4. |
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| 5. |
- Bilstrup, Urban, et al.
(författare)
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A fault tolerance test enabling QoS in a Bluetooth piconet
- 2004
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Konferensbidrag (populärvet., debatt m.m.)abstract
- An important trend, in personal area networks, is that time critical application becomes more common, e.g., voice over IP, video phone calls, network games. This segment of applications demands for quality of service (QoS) guarantees, to provide the correct functionality. The Bluetooth standard provides an optional interface to support QoS guarantees, but the standard does not suggest any actual implementation. A wireless communication channel is stochastic by nature, providing QoS guarantees with this precondition make traditional deterministic real-time theory obsolete. In this paper a probabilistic fault tolerance test enabling quality of service guarantees in a Bluetooth piconet is given. The basic Bluetooth network architecture is based on a master-slave configuration, i.e., a point to point connection. More advanced network architectures are possible where up to eight Bluetooth equipped units can be active members of one network (piconet). Furthermore, several piconets can interconnect and form a so called scatternet.
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| 6. |
- Bilstrup, Urban, et al.
(författare)
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Capacity limitations in wireless sensor networks
- 2003
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Ingår i: ETFA 2003. - Piscataway, N.J. : IEEE. - 0780379373 ; , s. 529-536
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Konferensbidrag (refereegranskat)abstract
- It is expected that wireless sensor network will be used in home automation and industrial manufacturing in the future. The main driving forces for wireless sensor networks are fault tolerance, energy gain and spatial capacity gain. Unfortunately, an often forgotten issue is the capacity limits that the network topology of a wireless sensor network represents. In this paper we identify gains, losses and limitations in a wireless sensor network, using a simplified theoretical network model. Especially, we want to point out the stringent capacity limitations that this simplified network model provide. Where a comparison between the locality of the performed information exchange and the average capacity available for each node is the main contribution.
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| 7. |
- Christoph, Mecklenbräuker, et al.
(författare)
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Vehicle-to-Vehicle Communications
- 2012
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Ingår i: Pervasive Mobile and Ambient Wireless Communications, Roberto Verdone and Alberto Zanella, editors. Springer. - London : Springer London. - 9781447123149 ; , s. 577-608
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Fricke, Katrin, et al.
(författare)
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Impact of Left Ventricular Morphology on Adverse Outcomes Following Stage 1 Palliation for Hypoplastic Left Heart Syndrome: 20 Years of National Data From Sweden
- 2022
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Ingår i: Journal of the American Heart Association. - : John Wiley & Sons. - 2047-9980. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hypoplastic left heart syndrome is associated with significant morbidity and mortality. We aimed to assess the influence of left ventricular morphology and choice of shunt on adverse outcome in patients with hypoplastic left heart syndrome and stage 1 palliation. METHODS AND RESULTS: This was a retrospective analysis of patients with hypoplastic left heart syndrome with stage 1 palliation between 1999 and 2018 in Sweden. Patients (n=167) were grouped based on the anatomic subtypes aortic-mitral atresia, aortic atresia-mitral stenosis (AA-MS), and aortic-mitral stenosis. The left ventricular phenotypes including globular left ventricle (Glob-LV), miniaturized and slit-like left ventricle (LV), and the incidence of major adverse events (MAEs) including mortality were assessed. The overall mortality and MAEs were 31% and 41%, respectively. AA-MS (35%) was associated with both mortality (all other subtypes versus AA-MS: interstage-I: hazard ratio [HR], 2.7; P=0.006; overall: HR, 2.2; P=0.005) and MAEs (HR, 2.4; P=0.0009). Glob-LV (57%), noticed in all patients with AA-MS, 61% of patients with aortic stenosis-mitral stenosis, and 19% of patients with aortic atresia-mitral atresia, was associated with both mortality (all other left ventricular phenotypes versus Glob-LV: interstage-I: HR, 4.5; P=0.004; overall: HR, 3.4; P=0.0007) and MAEs (HR, 2.7; P=0.0007). There was no difference in mortality and MAEs between patients with AA-MS and without AA-MS with Glob-LV (P>0.15). Patients with AA-MS (35%) or Glob-LV (38%) palliated with a Blalock-Taussig shunt had higher overall mortality compared with those palliated with Sano shunts, irrespective of the stage 1 palliation year (AA-MS: HR, 2.6; P=0.04; Glob-LV: HR, 2.1; P=0.03). CONCLUSIONS: Glob-LV and AA-MS are independent morphological risk factors for adverse short-and long-term outcome, especially if a Blalock-Taussig shunt is used as part of stage 1 palliation. These findings are important for the clinical management of patients with hypoplastic left heart syndrome.
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| 9. |
- Lidström, Kristoffer, 1981-, et al.
(författare)
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A Modular CACC System Integration Design
- 2012
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - Piscataway : IEEE Press. - 1524-9050 .- 1558-0016. ; 13:3, s. 1050-
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the Halmstad University entry in the GrCooperative Driving Challenge, which is a competition in vehicle platooning. Cooperative platooning has the potential to improve traffic flow by mitigating shock wave effects, which otherwise may occur in dense traffic. A longitudinal controller that uses information exchanged via wireless communication with other cooperative vehicles to achieve string-stable platooning is developed. The controller is integrated into a production vehicle, together with a positioning system, communication system, human€“machine interface (HMI). A highly modular system architecture enabled rapid development testing of the various subsystems. In the competition, which took place in May 2011 on a closed-off highway in The Netherlands, the Halmstad University team finished second among nine competing teams._x000D_
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| 10. |
- Lidström, Kristoffer, 1981-, et al.
(författare)
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Halmstad University Grand Cooperative Driving Challenge 2011 Technical Paper
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Traffic congestion is a large and growing problem in many countries due to an ever increasing number of vehicles. Increasing capacity by simply extending the road infrastructure is in many places impossible due to space and cost limitations. Everyday, people spend countless hours in car queues all over the world. The existing road infrastructure must be better utilized to save time and to reduce energy use. By enabling wireless communication between vehicles (V2V) and between vehicles and infrastructure (V2I) the flow of traffic can be better controlled in order to increase not only efficiency but also safety and comfort. Cooperative platooning is one way to increase efficiency by allowing vehicles to form road trains behind a lead vehicle. The Grand Cooperative Driving Challenge (GCDC) is an attempt to move towards a quicker deployment of cooperative platooning. This extended abstract gives an overview of Halmstad University’s team and its technical and organizational approach in preparing a vehicle for the competition.
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