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Abstract The 2018 eruption of Sierra Negra volcano, Galápagos, Ecuador has provided new insights into the mechanisms of caldera resurgence, subsidence, and fissuring at basaltic shield volcanoes. Here, we integrate local (∼0.4 km) seismo‐acoustic records and regional (∼85 km) infrasound array data to present new observations of the 2018 Sierra Negra eruption with improved time and spatial resolutions. These observations include: air‐to‐ground coupling ∼2 hr before the time of the eruption onset, migration of the infrasound tremor from 22:54 June 26 to 12:31 June 27 UT (all times in UT), and persistent infrasound detections during the weeks between 5 July and 18 August from an area that does not coincide with the previously documented eruptive fissures. We interpret air‐to‐ground coupling as infrasound tremor generated in the nearby fissures before the main eruptive phase started, although ambiguity remains in interpreting a single seismic‐infrasonic sensor pair. The progressive location change of the infrasound tremor agrees with the migration of the eruption down the north flank of Sierra Negra at a rate of ∼0.15 ± 0.04 m/s. The weeks‐long persistent detections coincide with a region that has thermal anomalies, co‐eruptive deformation, lava fields, and geological features that could be interpreted as multiple lava tube skylights. Our observations and interpretations provide constraints on the mechanisms underlying fissure formation and magma emplacement at Sierra Negra. 

This paper presents the application of a modified implementation of the StegBlocks TCP method as part of the Distributed Electronic Warfare System. The existing system is not equipped with a secure information communication mechanism for transmission between assimilated hosts and from hosts back to the server. The method implemented utilizes network steganography to provide covert data transmission through the network using network packets. The proposed implementation is compared to another implementation of the same method on the aspects of the implementations’ usability, versatility, and applicability. Discussion on how the proposed implementation is more suitable than the alternate implementation is presented. Future proposed improvements to the implementation are also discussed. 

A new image steganography method is proposed for data hiding. This method uses least significant bit (LSB) insertion to hide a message in one of the facial features of a given image. The proposed technique chooses an image of a face from a dataset of 8-bit color images of head poses and performs facial recognition on the image to extract the Cartesian coordinates of the eyes, mouth, and nose. A facial feature is chosen at random and each bit of the binary representation of the message is hidden at the least significant bit in the pixels of the chosen facial feature. © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. 

Anti-drone technologies that attack drone clusters or swarms autonomous command technologies may need to identify the type of command system being utilized and the various roles of particular UAVs within the system. This paper presents a set of algorithms to identify what swarm command method is being used and the role of particular drones within a swarm or cluster of UAVs utilizing only passive sensing techniques (which cannot be detected). A testing configuration for validating the algorithms is also discussed. © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.