Fault-tolerant and QoS based Network Layer for Security Management

Wireless sensor networks have profound effects on many application fields like security management which need an immediate, fast and energy efficient route. In this paper, we define a fault-tolerant and QoS based network layer for security management of chemical products warehouse which can be classified as real-time and mission critical application. This application generate routine data packets and alert packets caused by unusual events which need a high reliability, short end to end delay and low packet loss rate constraints. After each node compute his hop count and build his neighbors table in the initialization phase, packets can be routed to the sink. We use FELGossiping protocol for routine data packets and node-disjoint multipath routing protocol for alert packets. Furthermore, we utilize the information gathering phase of FELGossiping to update the neighbors table and detect the failed nodes, and we adapt the network topology changes by rerun the initialization phase when chemical units were added or removed from the warehouse. Analysis shows that the network layer is energy efficient and can meet the QoS constraints of unusual events packets

Random rerouting for differentiated QoS in sensor networks.

Sensor Networks consist of spatially distributed sensors which monitor an environment, and which are connected to some sinks or backbone system to which the sensor data is being forwarded. In many cases, the sensor nodes themselves can serve as intermediate nodes for data coming from other nodes, on the way to the sinks. Much of the traffic carried by sensor networks will originate from routine measurements or observations by sensors which monitor a particular situation, such as the temperature and humidity in a room or the infrared observation of the perimeter of a house, so that the volume of routine traffic resulting from such observations may be quite high. When important and unusual events occur, such as a sudden fire breaking out or the arrival of an intruder, it will be necessary to convey this new information very urgently through the network to a designated set of sink nodes where this information can be processed and dealt with. This paper addresses the important challenge of avoiding that the volume of routine background traffic may create delays or bottlenecks that impede the rapid delivery of high priority traffic resulting from the unusual events. Specifically we propose a novel technique, the "Randomized Re-Routing Algorithm (RRR)", which detects the presence of novel events in a distributed manner, and dynamically disperses the background traffic towards secondary paths in the network, while creating a "fast track path" which provides better delay and better QoS for the high priority traffic which is carrying the new information. When the surge of new information has subsided, this is again detected by the nodes and the nodes progressively revert to best QoS or shortest path routing for all the ongoing traffic. The proposed technique is evaluated using a mathematical model as well as simulations, and is also compared with a standard node by node priority scheduling technique

Kablosuz algılayıcı ağlar için öncelik tabanlı yeni bir yönlendirme protokolü tasarımı ve başarım analizi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Gelişen teknolojiyle birlikte boyutu küçük ve hata oranı düşük, işlem gücü ve iletim becerileri yüksek, üzerinde birden fazla algılayıcı barındırabilen uygun fiyatlı algılayıcı düğümler tasarlanabilmektedir. Algılama, hesaplama ve iletim yapabilen yüzlerce hatta binlerce algılayıcı düğüm bir araya gelerek kablosuz algılayıcı ağları oluşturur. Kablosuz algılayıcı ağlar düşük maliyetli ve çok işlevsel düğümlerden oluştuklarından genelde ulaşılması güç ve geniş alana sahip bölgelerde yapılan uygulamalarda öne çıkmaktadır. Enerji kaynakları sınırlı olan düğümlerin, bakım veya düzenleme yapılmaksızın uzun süre algılama ve iletim yapabilmeleri önemlidir. Kablosuz algılayıcı ağların en önemli problemlerinden birisi yönlendirmedir. Kendine özgü karakteristiklerinden dolayı kablosuz algılayıcı ağlara özel protokoller tasarlanması gerekmektedir. Yüzlerce düğümden oluşan kablosuz algılayıcı ağlar, birim zamanda çok fazla sayıda veri üretirler. Büyük miktarda üretilen verinin iletilmesi esnasında oluşacak tıkanıklık gibi durumlardan dolayı önemsiz veriler alıcıya teslim edilirken daha önemli verilerin alıcıya zamanında ya da hiç ulaştırılamaması ciddi bir problemdir. Yüksek öncelikli veriler yüksek paket teslim oranı ve beklenen düşük gecikme ile iletilemediğinde, doğal felaketler gibi acil tedbir üretilmesi gereken uygulamalarda hem maddi hem de manevi kayıplar yaşanır. Bu tez çalışmasında, kablosuz algılayıcı ağlarda veri önceliği kaynak düğüm tarafından belirlenen, yüksek öncelikli verilere daha iyi hizmet sağlarken tüm verilerin alıcıya teslim edilmesini hedefleyen “İşaretsiz Öncelik Tabanlı Yönlendirme – PBBR” (Priority Beaconless Based Routing) adı verilen yeni bir yönlendirme protokolü tasarlanmıştır. Tasarlanan “PBBR” protokolünün “Omnet++” benzetim aracı kullanılarak başarımı incelenmiştir. “PBBR” protokolü yönlendirme ek yükü, paket teslim oranı ve uçtan uca ortalama paket gecikmesi açısından yüksek başarım elde etmektedir. Bunlar dışında “PBBR” protokolü daha az bellek kapasitesi kullanmakta, veri üretilen sahanın genişliğini daha uzun süre korumakta ve her bölgeden veriyi hedef alıcıya ulaştırmaktadır. SUMMARYBy means of developing technology, it is possible to design sensor nodes with suitable prices, in small sizes, with low fault rates, containing more than one sensor and with high processing and transmitting capabilities. Wireless networks are built through thousands of combined sensor nodes which can sense, calculate and transmit. As wireless sensor networks are low cost and composed of multi-functional nodes, they are usually used in wide regions where access is difficult. It is important that they are able to sense and transmit for a long time without having any maintenance or adjustment with limited energy sources. One of the most important problems of wireless sensor networks is routing problem. Special protocols for the wireless sensor networks are required to be designed because of its own characteristics. Wireless sensor networks consisted of hundreds of nodes generate a great deal of data at a unit time. Because of situations like blockage while transmitting the huge generated data, not being able to deliver more important data in time or unable to deliver the data at all may emerge as a serious problem while insignificant data are delivered to the receiver. When high priority data with high packet delivery rates and the low expected delay cannot be transmitted, both material and spiritual losses are experienced in cases such as natural disasters which need urgent measures. In this thesis, a new routing protocol PBBR” (Priority Beaconless Based Routing) was designed which was determined by the source node wireless sensor networks and aimed delivering all data to the receiver as well as providing a better service for high priority data. The performance of the designed "PBBR" protocol was analyzed by simulation tool “Omnet ++”. PBBR protocol gives much better results according to routing additional load, packet delivery rate and end to end average packet delay. In addition to these, "PBBR" protocol uses less memory capacity, maintains the width of the area where the data are generated for a longer period and transmits data from each region to the target receiver

Technologies to improve the performance of wireless sensor networks in high-traffic applications

The expansion of wireless sensor networks to advanced areas, including structure health monitoring, multimedia surveillance, and health care monitoring applications, has resulted in new and complex problems. Traditional sensor systems are designed and optimised for extremely low traffic loads. However, it has been witnessed that network performance drops rapidly with the higher traffic loads common in advanced applications. In this thesis, we examine the system characteristics and new system requirements of these advanced sensor network applications. Based on this analysis, we propose an improved architecture for wireless sensor systems to increase the network performance while maintaining compatibility with the essential WSN requirements: low power, low cost, and distributed scalability. We propose a modified architecture deriving from the IEEE 802.15.4 standard, which is shown to significantly increase the network performance in applications generating increased data loads. This is achieved by introducing the possibility of independently allocating the sub-carriers in a distributed manner. As a result, the overall efficiency of the channel contention mechanism will be increased to deliver higher throughput with lower energy consumption. Additionally, we develop the concept of increasing the data transmission efficiency by adapting the spreading code length to the wireless environment. Such a modification will not only be able to deliver higher throughput but also maintain a reliable wireless link in the harsh RF environment. Finally, we propose the use of the battery recovery effect to increase the power efficiency of the system under heavy traffic load conditions. These three innovations minimise the contention window period while maximising the capacity of the available channel, which is shown to increase network performance in terms of energy efficiency, throughput and latency. The proposed system is shown to be backwards compatible and able to satisfy both traditional and advanced applications and is particularly suitable for deployment in harsh RF environments. Experiments and analytic techniques have been described and developed to produce performance metrics for all the proposed techniques

Smart Wireless Sensor Networks

The recent development of communication and sensor technology results in the growth of a new attractive and challenging area - wireless sensor networks (WSNs). A wireless sensor network which consists of a large number of sensor nodes is deployed in environmental fields to serve various applications. Facilitated with the ability of wireless communication and intelligent computation, these nodes become smart sensors which do not only perceive ambient physical parameters but also be able to process information, cooperate with each other and self-organize into the network. These new features assist the sensor nodes as well as the network to operate more efficiently in terms of both data acquisition and energy consumption. Special purposes of the applications require design and operation of WSNs different from conventional networks such as the internet. The network design must take into account of the objectives of specific applications. The nature of deployed environment must be considered. The limited of sensor nodes� resources such as memory, computational ability, communication bandwidth and energy source are the challenges in network design. A smart wireless sensor network must be able to deal with these constraints as well as to guarantee the connectivity, coverage, reliability and security of network's operation for a maximized lifetime. This book discusses various aspects of designing such smart wireless sensor networks. Main topics includes: design methodologies, network protocols and algorithms, quality of service management, coverage optimization, time synchronization and security techniques for sensor networks