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Distributed vibration sensing based on phase-sensitive optical time domain reflectometry (ϕ-OTDR) is being widely used in several applications. However, one of the main challenges in coherent detection-based ϕ-OTDR systems is the fading noise, which impacts the detection performance. In addition, typical signal averaging and differentiating techniques are not suitable for detecting high frequency events. This paper presents a new approach for reducing the effect of fading noise in fiber optic distributed acoustic vibration sensing systems without any impact on the frequency response of the detection system. The method is based on temporal adaptive processing of ϕ-OTDR signals. The fundamental theory underlying the algorithm, which is based on signal-to-noise ratio (SNR) maximization, is presented, and the efficacy of our algorithm is demonstrated with laboratory experiments and field tests. With the proposed digital processing technique, the results show that more than 10 dB of SNR values can be achieved without any reduction in the system bandwidth and without using additional optical amplifier stages in the hardware. We believe that our proposed adaptive processing approach can be effectively used to develop fiber optic-based distributed acoustic vibration sensing systems.

Critics of the current national citizenship models argue that, although it rests on claims to be inclusionary and universal, it can never eliminate exclusionary and particularistic practices when challenged by those identities excluded from the historical trajectory of "nation building." Turkish citizenship has been a form of anomalous amalgamation since its conception. On the one hand, the state insisted on the pre-emptive exclusion of religion and various communal cultural identities from politics, while, on other hand, it promoted a particular religious identity primarily as a means of promoting cultural and social solidarity among its citizens. Contemporary Alevi movements, representing the interests of a large minority in Turkey, provide a new source of energy for the revision of concepts of citizenship. Alevis have suffered from prejudice, and their culture has been arrested and excluded from the nation building process. They were not able to integrate into the form of national identity based on the "secular" principles that the republican state has provided as a means of promoting solidarity among citizens. What Alevis seek is a revised citizenship model in terms of a system of rights assuring the condition of neutrality among culturally diverse individuals.

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