Search results for "NETWORKS"
showing 10 items of 3260 documents
Design of energy efficient MAC protocols in wireless sensor networks
2014
Masteroppgave i Informasjons- og kommunikasjonsteknologi IKT590 Universitetet i Agder 2014 Wireless sensor networks (WSNs) have been used in variety of applications such as in military and defense, process control industry and health monitoring applications. In WSNs, sensors are in small size with limited battery capacity and idle listening is a crucial problem which consumes more energy. Duty cycling (DC) is a technique which is used in many medium access control (MAC) protocols to reduce idle listening. In this thesis, we propose an asynchronous DC protocol, namely energy balancing asynchronous cooperative transmission medium access control (EB-ACT-MAC), which balances the remaining energ…
Multi-purpose embedded communication gateway : system design and testbed implementation
2014
Masteroppgave i Informasjons- og kommunikasjonsteknologi IKT590 Universitetet i Agder 2014 This dissertation revolves around developing a multi-purpose embedded communication gateway. The gateway is equipped with multiple communication interfaces including Ethernet, Bluetooth, WiFi, Zigbee, LTE, and it can be configured and utilized for many purposes, such as a failover of an Ethernet cable via 4G in order to maintain the network connectivity. Raspberry Pi circuit board and the operating system Raspbian are selected as the hardware and the software platforms respectively. Different communication interfaces are coordinated by the Raspberry Pi and are configured via Linux scripts according to…
Seamless Hand-over Algorithm for Wireless Enterprise Networks
2007
Masteroppgave i informasjons- og kommunikasjonsteknologi 2007 – Høgskolen i Agder, Grimstad The mass deployment of the Institute of Electrical and Electronics Engineers’ (IEEE) 802.11 based wireless local area networks (WLAN) and increased sales in hand-held devices supporting WLAN have resulted in an urgent need to support fast WLAN handovers or roaming. The reason for this problem arising now is that hand-held devices are more mobile than a laptop and their users actively use their hand-held equipment while moving. Laptop users are often called nomadic users in contrast to the real mobile users. The customarily solution is that when a connection is lost with the associated access point, o…
OpenIMS and Interoperability with Asterisk/Sip Express VOIP Enterprise Solutions
2007
Masteroppgave i informasjons- og kommunikasjonsteknologi 2007 – Høgskolen i Agder, Grimstad Nowadays, with the development of the next-generation network, IMS becomes very important, and it will play a key role in the future All-IP infrastructure. But it is still in the developing stage, and it will take time for all 3G mobile networks upgrade to 3GPP networks. Therefore, the research project will study the interoperability solutions between Open Source IMS and Open Source VoIP/SIP implementations. This project is supported by auSystems and HiA. OpenIMS (Open Source IMS) was developed by FOKUS (a Germany institution) in December 2006. It is a free IMS enterprise solution. As it is so new, t…
Handling of IP-Addresses in the Context of Remote Access
2008
Masteroppgave i informasjons- og kommunikasjonsteknologi 2008 – Universitetet i Agder, Grimstad For various reasons (e.g., security, lack of IPv4-addresses) the services in the home smart space only use private IP addresses. This is unfortunate in the remote service access since these addresses frequently appear in responses sent from a service in the remote smart space (e.g., your home) to the visited smart space (e.g., your friend’s home).The Internet Engineering Task Force (IETF) provides some solutions and workarounds for the problem caused by NAT. In this project, the challenge to me is to summarize the available options, rank the options according to which one is preferred for the RA-…
Accurate Measurement and Visualization of Traffic Load in IEEE 802.11 WLANs
2008
Masteroppgave i informasjons- og kommunikasjonsteknologi 2008 – Universitetet i Agder, Grimstad Wireless Local Area Networks (WLANs) based on the IEEE 802.11 standard are getting very popular these days, due to their support for new multimedia services and VoIP, and because WLANs are appearing on more and more small devices. This causes a steadily increasing load and becomes a challenge to network administrators who want to make their WLANs run efficiently and to keep the users satisfied. This Master thesis addresses the lack of efficient and affordable monitoring tools for those running WLANs, by developing an accurate method and for the visualization of traffic patterns and bandwidth util…
Modeling and verifying the OLSR protocol using Uppaal
2014
Masteroppgave i Informasjons- og kommunikasjonsteknologi IKT590 Universitetet i Agder 2014 Wireless Mesh Networks (WMNs) are a popular technology due to their exibility andself-organizing nature that provide support for broadband communication. They areused in a wide range of application areas, such as public transportation, tunnels, realtime racing car telemetry and emergency response communication. Route _nding andmaintenance, two important factors determining the performance of such networks,are provided using routing algorithms. The Optimized Link State Routing (OLSR)protocol is an example of such algorithms which is used in this study.One issue about this protocol is that its speci_cat…
Dominating Clasp of the Financial Sector Revealed by Partial Correlation Analysis of the Stock Market
2010
What are the dominant stocks which drive the correlations present among stocks traded in a stock market? Can a correlation analysis provide an answer to this question? In the past, correlation based networks have been proposed as a tool to uncover the underlying backbone of the market. Correlation based networks represent the stocks and their relationships, which are then investigated using different network theory methodologies. Here we introduce a new concept to tackle the above question--the partial correlation network. Partial correlation is a measure of how the correlation between two variables, e.g., stock returns, is affected by a third variable. By using it we define a proxy of stoc…
Gatherer: an environmental monitoring application based on IPv6 using wireless sensor networks
2013
In this paper, we present an environmental monitoring application based on IPv6 using wireless sensor networks. We show the guidelines to connect this network to internet using the 6LowPAN standard with a real prototype in the evolution of the Internet of Things. We assign a unique IPv6 address to the different nodes motes of the network. Gatherer is based on TinyOS using IPv6 and UDP protocols and allows the data gathering of temperature and relative humidity from the different motes, requesting specific data from individual motes when required, increasing the accuracy of the measures. We compare the performance of our IPv6-based proposed application against others and show the benefits of…