scholarly journals Broadcasting in VANET: State of the Art

2019 ◽  
Vol 8 (4) ◽  
pp. 5653-5658
Keyword(s):  
Traffic Congestion ◽  
Ad Hoc ◽  
Relevant Information ◽  
Limited Range ◽  
Radio Communication ◽  
Hidden Node ◽  
Minimum Bandwidth ◽  
To Receive ◽  
Broadcast Protocol ◽  
Node Problem

Vehicular ad-hoc network (VANET) is in the offing as the most promising technology to resolve all kinds of traffic problems such as those related to traffic congestion, road mishaps, and address upbringing issue such as those pertaining to noxious emissions. In VANET, relevant information should be disseminated with a minimum bandwidth usage thus requiring an efficient and dependable multi-hop data broadcast protocol. Broadcasting play an important role in VANET to distribution of information from vehicle to all neighboring vehicle for some specific purpose. It reduces collision, contention, redundant messages and hidden node problem. It also improves the message reliability. Due to limited range of radio communication in VANET, all the vehicles may not be able to receive the broadcast data in a single hop. So multi-hop communication is needed. This article investigates and compares the various multihop broadcasting protocols

QoS Support in Multi-hop Ad-hoc Networks

2010 ◽  
pp. 230-270 ◽  
Author(s):  
Marek Natkaniec ◽  
Katarzyna Kosek-Szott ◽  
Szymon Szott
Keyword(s):  
Ad Hoc Networks ◽  
Ad Hoc ◽  
Qos Provisioning ◽  
Medium Access ◽  
Data Link ◽  
Data Link Layer ◽  
Hidden Node ◽  
Hoc Networks ◽  
Future Work ◽  
Node Problem

The chapter contains an overview of existing QoS solutions for multi-hop ad-hoc networks. Firstly, an introduction and short motivation are presented. The authors present an analysis of the QoS aspects of the physical layer because the wireless communication channel is constantly changing and inherently prone to errors. QoS provisioning at the data link layer is studied next. The authors focus on protocols which enable traffic differentiation, solve the hidden node problem and provide fair medium access. The chapter also deals with QoS issues at the network layer, where the authors mostly discuss QoS routing protocols. Additionally, cross-layer solutions for QoS support in multi-hop ad-hoc networks are analyzed. Finally, the expected direction of future work and a brief summary are presented.

scholarly journals Production, Validation and Morphometric Analysis of a Digital Terrain Model for Lake Trichonis Using Geospatial Technologies and Hydroacoustics

2021 ◽  
Vol 10 (2) ◽  
pp. 91
Author(s):  
Triantafyllia-Maria Perivolioti ◽  
Antonios Mouratidis ◽  
Dimitrios Terzopoulos ◽  
Panagiotis Kalaitzis ◽  
Dimitrios Ampatzidis ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Ad Hoc ◽  
Regional Scale ◽  
Digital Terrain Model ◽  
Relevant Information ◽  
Relative Difference ◽  
Systematic Observation ◽  
Qualitative And Quantitative ◽  
Terrain Model ◽  
Digital Terrain

Covering an area of approximately 97 km2 and with a maximum depth of 58 m, Lake Trichonis is the largest and one of the deepest natural lakes in Greece. As such, it constitutes an important ecosystem and freshwater reserve at the regional scale, whose qualitative and quantitative properties ought to be monitored. Depth is a crucial parameter, as it is involved in both qualitative and quantitative monitoring aspects. Thus, the availability of a bathymetric model and a reliable DTM (Digital Terrain Model) of such an inland water body is imperative for almost any systematic observation scenario or ad hoc measurement endeavor. In this context, the purpose of this study is to produce a DTM from the only official cartographic source of relevant information available (dating back approximately 70 years) and evaluate its performance against new, independent, high-accuracy hydroacoustic recordings. The validation procedure involves the use of echosoundings coupled with GPS, and is followed by the production of a bathymetric model for the assessment of the discrepancies between the DTM and the measurements, along with the relevant morphometric analysis. Both the production and validation of the DTM are conducted in a GIS environment. The results indicate substantial discrepancies between the old DTM and contemporary acoustic data. A significant overall deviation of 3.39 ± 5.26 m in absolute bottom elevation differences and 0.00 ± 7.26 m in relative difference residuals (0.00 ± 2.11 m after 2nd polynomial model corrector surface fit) of the 2019 bathymetric dataset with respect to the ~1950 lake DTM and overall morphometry appear to be associated with a combination of tectonics, subsidence and karstic phenomena in the area. These observations could prove useful for the tectonics, geodynamics and seismicity with respect to the broader Corinth Rift region, as well as for environmental management and technical interventions in and around the lake. This dictates the necessity for new, extensive bathymetric measurements in order to produce an updated DTM of Lake Trichonis, reflecting current conditions and tailored to contemporary accuracy standards and state-of-the-art research in various disciplines in and around the lake.

scholarly journals Comparison of Different Analytical Methods for the On-Site Analysis of Traces at Clandestine Drug Laboratories

2021 ◽  
Vol 11 (9) ◽  
pp. 3754
Author(s):  
René Reiss ◽  
Frank Hauser ◽  
Sven Ehlert ◽  
Michael Pütz ◽  
Ralf Zimmermann
Keyword(s):  
Large Scale ◽  
Ambient Pressure ◽  
Relevant Information ◽  
Information Value ◽  
Site Analysis ◽  
Complex Information ◽  
Skilled Operator ◽  
Validation Parameters ◽  
Clandestine Laboratories ◽  
To Receive

While fast and reliable analytical results are crucial for first responders to make adequate decisions, these can be difficult to establish, especially at large-scale clandestine laboratories. To overcome this issue, multiple techniques at different levels of complexity are available. In addition to the level of complexity their information value differs as well. Within this publication, a comparison between three techniques that can be applied for on-site analysis is performed. These techniques range from ones with a simple yes or no response to sophisticated ones that allows to receive complex information about a sample. The three evaluated techniques are immunoassay drug tests representing easy to handle and fast to explain systems, ion mobility spectrometry as state-of-the-art equipment that needs training and experience prior to use and ambient pressure laser desorption with the need for a highly skilled operator as possible future technique that is currently under development. In addition to the measurement of validation parameters, real case samples are investigated to obtain practically relevant information about the capabilities and limitations of these techniques for on-site operations. Results demonstrate that in general all techniques deliver valid results, but the bandwidth of information widely varies between the investigated techniques.

scholarly journals A Survey on Applications of Reinforcement Learning in Flying Ad-Hoc Networks

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 449
Author(s):  
Sifat Rezwan ◽  
Wooyeol Choi
Keyword(s):  
Reinforcement Learning ◽  
Ad Hoc Networks ◽  
Wireless Ad Hoc Networks ◽  
Routing Protocol ◽  
Traffic Congestion ◽  
Ad Hoc ◽  
High Mobility ◽  
Flight Trajectory ◽  
Research Issues ◽  
Hoc Networks

Flying ad-hoc networks (FANET) are one of the most important branches of wireless ad-hoc networks, consisting of multiple unmanned air vehicles (UAVs) performing assigned tasks and communicating with each other. Nowadays FANETs are being used for commercial and civilian applications such as handling traffic congestion, remote data collection, remote sensing, network relaying, and delivering products. However, there are some major challenges, such as adaptive routing protocols, flight trajectory selection, energy limitations, charging, and autonomous deployment that need to be addressed in FANETs. Several researchers have been working for the last few years to resolve these problems. The main obstacles are the high mobility and unpredictable changes in the topology of FANETs. Hence, many researchers have introduced reinforcement learning (RL) algorithms in FANETs to overcome these shortcomings. In this study, we comprehensively surveyed and qualitatively compared the applications of RL in different scenarios of FANETs such as routing protocol, flight trajectory selection, relaying, and charging. We also discuss open research issues that can provide researchers with clear and direct insights for further research.

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