Detecting Tunnels for Border Security based on Fiber Optical Distributed Acoustic Sensor Data using DBSCAN Topics: Big Data; Computational Intelligence; Cross-Layer Design; Data Quality and Integrity; Decision Support Systems; Defense and Security; Environment Monitoring; Information Retrieval and Data Mining; Multi-Sensor Data Processing; Optical Sensors; Programming and Middleware; Scheduling, Tasking and Control; Security Threats In Proceedings of the 9th International Conference on Sensor Networks SENSORNETS - Volume 1, 78-84, 2020 , Valletta, Malta