Search results for "Networks"
showing 10 items of 3260 documents
Model-based verification of the DMAMAC protocol for real-time process control
2015
Medium Access Control (MAC) protocols are responsible for managing radio communication that constitute the main energy consumer in wireless sensor-actuator networks. The Dual-Mode Adaptive MAC (DMAMAC) protocol is a recently proposed MAC protocol for process control applications within industrial automation. The goal of the DMAMAC protocol is to improve energy efficiency along with addressing real-time requirements for process control applications. The DMAMAC protocol switches between two operational modes that correspond to the two main states in process control: the transient state and the steady state. The state-switch is a safety critical function of the DMAMAC protocol (along with othe…
Fault-tolerant routing in adversarial mobile ad hoc networks: an efficient route estimation scheme for non-stationary environments
2010
Published version of an article from the journal: Telecommunication systems. The original publication is available at Spingerlink. http://dx.doi.org/DOI: 10.1007/s11235-009-9215-4 Designing routing schemes that would successfully operate in the presence of adversarial environments in Mobile Ad Hoc Networks (MANETs) is a challenging issue. In this paper, we discuss fault-tolerant routing schemes operating in a network with malfunctioning nodes. Most existing MANET protocols were postulated considering scenarios where all the mobile nodes in the ad hoc network function properly, and in an idealistic manner. However, adversarial environments are common in MANET environments, and misbehaving no…
Cooperative Medium Access Mechanisms and Service-oriented Routing in Multi-hop Wireless Networks
2011
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2011 Multi-hop wireless networks have been regarded as a promising path towards future wireless communication landscape. In the past decade, most related work has been performed in the context of mobile ad hoc networks. In very recent years, however, much effort has been shifted to more static networks such as wireless mesh networks and wireless sensor networks. While significant progress has been achieved through these years, both theoretically and experimentally, challenges still exist in various aspects of these networks. For instance, how to use multi-hop networks as a means for providing …
Cooperative retransmission implementation in ns 2
2010
Masteroppgave i informasjons- og kommunikasjonsteknologi 2010 – Universitetet i Agder, Grimstad From the theoretical perspective cooperative communications are reasonably well understood. But in practical realizations of cooperative communication system are still quite limited, the articles in this special issue are devoted to implementation aspects related to cooperative retransmission implementation in ns 2.system..Cooperative retransmission in wireless networks has attracted many research attentions which is the basic idea when a receiver cannot decode a frame, the retransmission is handled not by its original source but rather by a neighbor that overheard the transmission successfully, …
Cooperative Communications inWireless Local Area Networks: MAC Protocol Design and Multi-layer Solutions
2012
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2012 This dissertation addresses cooperative communications and proposes multi-layer solu- tions for wireless local area networks, focusing on cooperative MAC design. The coop- erative MAC design starts from CSMA/CA based wireless networks. Three key issues of cooperation from the MAC layer are dealt with: i.e., when to cooperate (opportunistic cooperation), whom to cooperate with (relay selection), and how to protect cooperative transmissions (message procedure design). In addition, a cooperative MAC protocol that addresses these three issues is proposed. The relay selection scheme is further…
Investigating Power Consumption in 802.11 WLANs: Measurement, Visualization, and Improvement
2009
Masteroppgave i informasjons- og kommunikasjonsteknologi 2009 – Universitetet i Agder, Grimstad 802.11 based wireless local area network (WLAN) has been increasingly supported by handheld devices. However, supporting WLAN functionality is extremely energy consuming since the connectivity has to be maintained even when the device is in an idle state. The power management specified in the 802.11 standards do not specify detailed techniques to handle the problem caused by power consumption affecting factors (PCAFs), since most of these factors have not been specified in the standards. The objective of this master dissertation is to investigate how different PCAFs affect the power consumption i…
Ad-hoc network for oil supply boats
2009
Masteroppgave i informasjons- og kommunikasjonsteknologi 2009 – Universitetet i Agder, Grimstad An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without any fixed infrastructure like access points or base stations. Each node in ad hoc network is willing to forward data for other nodes, and the determination of which nodes forward data is made dynamically based on the network connectivity. Mobile ad hoc networking can offer multiple advantages in various environments through its flexibility and its special nature. One such environment is maritime communications. The MARCOM Project currently has shown that a definite protocol simulation of mar…
Design a WLAN mini access point in the android platform
2010
Masteroppgave i informasjons- og kommunikasjonsteknologi 2010 – Universitetet i Agder, Grimstad Mobile as a computing platform is becoming more and more popular. The amount of such devices shipped every year is growing rapidly, more than 1.2 billion in 2009. At the same time the WLAN is being widely adapted at various locations like campuses, meeting rooms, stations, etc. Currently almost all smart phones come with the support for the WLAN. However, most the mobile devices can only behavior as a client in the WLAN. It would be a remarkable feature if the mobile device is able to function as an Access Point (AP) and a modem which forwards data between the 3G network and the WLAN. Android des…
How Vulnerable is the Reaction Time Concealed Information Test to Faking?
2021
The reaction time-based Concealed Information Test (RT-CIT) can be used to detect information a suspect wishes to conceal. While it is often argued that it is easily faked, empirical research on its vulnerability to faking is scarce. In three experiments, we tested whether receiving faking instructions enables guilty participants to fake an innocent test outcome in an RT-CIT. In Experiment 1, when not using a response deadline, we found the RT-CIT to be vulnerable to faking (d = 1.06). Experiment 2 showed that when using a response deadline, faking was ineffective (d = −0.25). Critically, Experiment 3 replicated these findings within one between-subject design, showing again a faking effect…