Deprem erken uyarı sistemleri ve optik WDM ağlarının entegrasyon teknikleri

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.Veri taşıyıcısı olarak ışığın kullanıldığı iletişim teknolojileri son yıllarda hızla yaygınlaşmaktadır. Bu gelişme ile birlikte telekom altyapısında fiber optik ağların kullanılması artmıştır. İletişimin bu denli önemli olduğu günümüzde, herhangi bir doğal afette iletişimin sağlanabilmesi için verinin güvenli ve hızlı bir şekilde karşı tarafa ulaştırılması gerekmektedir. Telekom altyapısında fiber optik ağların kullanılmasıyla iletişimin hızlı bir şekilde sağlanması amaçlanmıştır. Sarsıntılar omurga telekom altyapısını vurduğunda depremler büyük veri kaybına yol açar. Bununla birlikte eğer Erken Uyarı Sistemleri (EWS) Optik Dalga Boyu Bölmeli Çoklama (WDM) ağlar ile entegre edilirse gerekli önlemler alınabilir. EWS demir yolu ulaşımında, nükleer enerji santralinde ya da yarı iletken fabrikalarda kullanılırken telekom ağlarını uyarmak için kullanılmamıştır. Büyük bir deprem meydana gelmeden uyarı sağlanabilirse veri kaybını önlemek için birçok bağlantı yeniden sağlanabilir. Bu çalışmada, bu amaçla Deprem Erken Uyarı Sistemleri (EEWS) ile optik WDM ağlarının entegrasyonu için teknikler geliştirilmiştir. Optik ağ üzerinde birbirine bağlı olan düğümlerin oluşturduğu örnek bir ağ topolojisinde olası bir felaket sırasında iletişimin tekrar sürdürebilmesi için bağlantılar yeniden sağlanmıştır. Teknikler birbiri ile karşılaştırılarak en iyi sonucu veren yaklaşım bulunmuştur.Communication technologies in which light is used as a data carrier have been rapidly spreading in recent years. With this development, the use of fiber optic networks has increased in telecom infrastructure. Communication is so important nowadays that in order to ensure communication in disaster, the data must be delivered to the other side safely and quickly. It is aimed to provide communication in a fast way by using fiber optic networks in telecom infrastructure. Earthquakes can cause massive data loss when shakes hit the backbone telecom infrastructure. However, if Early Warning Systems (EWS) are integrated with optical WDM networks, necessary preventions can be taken. EWS are not used to warn telecom networks that are used in railway transport, in nuclear power plants or in semiconductor factories. In this study, techniques have been developed for the integration of Earthquake Early Warning Systems (EEWS) and optical wavelength division multiplexing (WDM) networks for this purpose. An example of a network topology created by interconnected nodes on the optical network is reestablished so that communication can resume during a catastrophic event. Techniques were compared with each other to find the best result

Disaster Resilient Optical Core Networks

During the past few years, the number of catastrophic disasters has increased and its impact sometimes incapacitates the infrastructures within a region. The communication network infrastructure is one of the affected systems during these events. Thus, building a resilient network backbone is essential due to the big role of networks during disaster recovery operations. In this thesis, the research efforts in building a disaster-resilient network are reviewed and open issues related to building disaster-resilient networks are discussed. Large size disasters not necessarily impact the communication networks, but instead it can stimulate events that cause network performance degradation. In this regard, two open challenges that arise after disasters are considered one is the short-term capacity exhaustion and the second is the power outage. First, the post-disaster traffic floods phenomena is considered. The impact of the traffic floods on the optical core network performance is studied. Five mitigation approaches are proposed to serve these floods and minimise the incurred blocking. The proposed approaches explore different technologies such as excess or overprovisioned capacity exploitation, traffic filtering, protection paths rerouting, rerouting all traffic and finally using the degrees of freedom offered by differentiated services. The mitigation approaches succeeded in reducing the disaster induced traffic blocking. Second, advance reservation provisioning in an energy-efficient approach is developed. Four scenarios are considered to minimise power consumption. The scenarios exploit the flexibility provided by the sliding-window advance reservation requests. This flexibility is studied through scheduling and rescheduling scenarios. The proposed scenarios succeeded in minimising the consumed power. Third, the sliding-window flexibility is exploited for the objective of minimising network blocking during post-disaster traffic floods. The scheduling and rescheduling scenarios are extended to overcome the capacity exhaustion and improve the network blocking. The proposed schemes minimised the incurred blocking during traffic floods by exploiting sliding window. Fourth, building blackout resilient networks is proposed. The network performance during power outages is evaluated. A remedy approach is suggested for maximising network lifetime during blackouts. The approach attempts to reduce the required backup power supply while minimising network outages due to limited energy production. The results show that the mitigation approach succeeds in keeping the network alive during a blackout while minimising the required backup power

A framework for traffic flow survivability in wireless networks prone to multiple failures and attacks

Transmitting packets over a wireless network has always been challenging due to failures that have always occurred as a result of many types of wireless connectivity issues. These failures have caused significant outages, and the delayed discovery and diagnostic testing of these failures have exacerbated their impact on servicing, economic damage, and social elements such as technological trust. There has been research on wireless network failures, but little on multiple failures such as node-node, node-link, and link–link failures. The problem of capacity efficiency and fast recovery from multiple failures has also not received attention. This research develops a capacity efficient evolutionary swarm survivability framework, which encompasses enhanced genetic algorithm (EGA) and ant colony system (ACS) survivability models to swiftly resolve node-node, node-link, and link-link failures for improved service quality. The capacity efficient models were tested on such failures at different locations on both small and large wireless networks. The proposed models were able to generate optimal alternative paths, the bandwidth required for fast rerouting, minimized transmission delay, and ensured the rerouting path fitness and good transmission time for rerouting voice, video and multimedia messages. Increasing multiple link failures reveal that as failure increases, the bandwidth used for rerouting and transmission time also increases. This implies that, failure increases bandwidth usage which leads to transmission delay, which in turn slows down message rerouting. The suggested framework performs better than the popular Dijkstra algorithm, proactive, adaptive and reactive models, in terms of throughput, packet delivery ratio (PDR), speed of transmission, transmission delay and running time. According to the simulation results, the capacity efficient ACS has a PDR of 0.89, the Dijkstra model has a PDR of 0.86, the reactive model has a PDR of 0.83, the proactive model has a PDR of 0.83, and the adaptive model has a PDR of 0.81. Another performance evaluation was performed to compare the proposed model's running time to that of other evaluated routing models. The capacity efficient ACS model has a running time of 169.89ms on average, while the adaptive model has a running time of 1837ms and Dijkstra has a running time of 280.62ms. With these results, capacity efficient ACS outperforms other evaluated routing algorithms in terms of PDR and running time. According to the mean throughput determined to evaluate the performance of the following routing algorithms: capacity efficient EGA has a mean throughput of 621.6, Dijkstra has a mean throughput of 619.3, proactive (DSDV) has a mean throughput of 555.9, and reactive (AODV) has a mean throughput of 501.0. Since Dijkstra is more similar to proposed models in terms of performance, capacity efficient EGA was compared to Dijkstra as follows: Dijkstra has a running time of 3.8908ms and EGA has a running time of 3.6968ms. In terms of running time and mean throughput, the capacity efficient EGA also outperforms the other evaluated routing algorithms. The generated alternative paths from these investigations demonstrate that the proposed framework works well in preventing the problem of data loss in transit and ameliorating congestion issue resulting from multiple failures and server overload which manifests when the process hangs. The optimal solution paths will in turn improve business activities through quality data communications for wireless service providers.School of ComputingPh. D. (Computer Science

A Matter of Survival. Arctic Communications Infrastructure in the 21st CenturyArctic Communications Infrastructure Assessment (ACIA)

The Arctic Communications Infrastructure Assessment (ACIA) identifies the issues and challenges facing governments and service providers in ensuring the Canadian Arctic is properly connected for the benefit of Arctic citizens and all Canadians

China's cyber warfare : the strategic value of cyberspace and the legacy of people's war

NoneEThOS - Electronic Theses Online ServiceGBUnited Kingdo

China's cyber warfare : the strategic value of cyberspace and the legacy of people's war

NoneEThOS - Electronic Theses Online ServiceGBUnited Kingdo

China's cyber warfare :the strategic value of cyberspace and the legacy of people's war

PhD ThesisNon

Earthquake Preparedness Strategies for Telecom Backbone with Integration of Early Warning Systems and Optical WDM Networks (Invited Paper)

In this study, we explore three different strategies for such situation; 1) Extreme approach that reprovisions all connections in danger with full or degraded bandwidth, 2) relax approach that reprovisions only critical connections, and 3) careful approach that reprovisions some or all connections based on the alarm level. We compare these strategies for a case study, an earthquake on San Andreas Fault Line. We conduct numerical examples over a 24-node US-wide topology where the connections have heterogeneous bandwidth and availability requirements. The numerical examples show that careful approach provides a better solution than extreme and relax approaches, especially for heavy network loads in terms of expected penalty in case of an earthquake

Earthquake Preparedness Strategies for Telecom Backbone with Integration of Early Warning Systems and Optical WDM Networks (Invited Paper)

In this study, we explore three different strategies for such situation; 1) Extreme approach that reprovisions all connections in danger with full or degraded bandwidth, 2) relax approach that reprovisions only critical connections, and 3) careful approach that reprovisions some or all connections based on the alarm level. We compare these strategies for a case study, an earthquake on San Andreas Fault Line. We conduct numerical examples over a 24-node US-wide topology where the connections have heterogeneous bandwidth and availability requirements. The numerical examples show that careful approach provides a better solution than extreme and relax approaches, especially for heavy network loads in terms of expected penalty in case of an earthquake