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Gaze-based interaction is a fast and ergonomic type of hands-free interaction that is often used with augmented and virtual reality when pointing at targets. Such interaction, however, can be cumbersome whenever user, tracking, or environmental factors cause eye tracking errors. Recent research has suggested that fallback modalities could be leveraged to ensure stable interaction irrespective of the current level of eye tracking error. This work thus presents Weighted Pointer interaction, a collection of error-aware pointing techniques that determine whether pointing should be performed by gaze, a fallback modality, or a combination of the two, depending on the level of eye tracking error that is present. These techniques enable users to accurately point at targets when eye tracking is accurate and inaccurate. A virtual reality target selection study demonstrated that Weighted Pointer techniques were more performant and preferred over techniques that required the use of manual modality switching.

The rare occurrence of a sound deviating from the auditory background tends to trigger attentional orienting. While some sympathetic physiological responses can be used to index this orienting response, findings surrounding the pupillary dilation response (PDR) as a proxy for the orienting response are conflicting. The current study was tailor-designed to examine whether the PDR satisfies specific criteria of an orienting response index, namely the classic habituation pattern and a sensitivity to the size of the deviation. The PDR decrement to a repeated standard sound, recovery to a deviant sound, and dishabituation to the re-presentation of the standard were assessed for small and large deviations embedded in irrelevant auditory sequences. The PDR not only showed habituation and dishabituation, but also recovered in correspondence with the magnitude of the acoustic deviation. This consistency between variations of the PDR and orienting response's properties indicates that the PDR is a valid index of the auditory orienting response.

Finding a physiological signature of a player’s fun is a goal yet to be achieved in the field of adaptive gaming. The research presented in this paper tackles this issue by gathering physiological, behavioural and self-report data from over 200 participants who played off-the-shelf video games from the Assassin’s Creed series within a minimally invasive laboratory environment. By leveraging machine learning techniques the prediction of the player’s fun from its physiological and behavioural markers becomes a possibility. They provide clues as to which signals are the most relevant in establishing a physiological signature of the fun factor by providing an important score based on the predictive power of each signal. Identifying those markers and their impact will prove crucial in the development of adaptive video games. Adaptive games tailor their gameplay to the affective state of a player in order to deliver the optimal gaming experience. Indeed, an adaptive video game needs a continuous reading of the fun level to be able to respond to these changing fun levels in real time. While the predictive power of the presented classifier remains limited with a gain in the F1 score of 15% against random chance, it brings insight as to which physiological features might be the most informative for further analysis and discuss means by which low accuracy classification could still improve gaming experience.

Finding a physiological signature of a player’s fun is a goal yet to be achieved in the field of adaptive gaming. The research presented in this paper tackles this issue by gathering physiological, behavioural and self-report data from over 200 participants who played off-the-shelf video games from the Assassin’s Creed series within a minimally invasive laboratory environment. By leveraging machine learning techniques the prediction of the player’s fun from its physiological and behavioural markers becomes a possibility. They provide clues as to which signals are the most relevant in establishing a physiological signature of the fun factor by providing an importance score based on the predictive power of each signal. Identifying those markers and their impact will prove crucial in the development of adaptive video games. Adataptive games that tailor their gameplay to the affective state of a player in order to deliver the optimal gaming experience. Indeed, an adaptive video game needs a continuous reading of the fun level to be able to respond to these changing fun levels in real time. While the predictive power of the presented classifier remains limited with a gain in the F1 score of 15% against random chance, it brings insight as to which physiological features might be the most informative for further analyses and discuss means by which low accuracy classification could still improve gaming experience.

The rare occurrence of a sound deviating from the auditory background tends to trigger attentional orienting. While some sympathetic physiological responses can be used to index this orienting response, findings surrounding the pupillary dilation response (PDR) as a proxy for the orienting response are conflicting. The current study was tailor-designed to examine whether the PDR satisfies specific criteria of an orienting response index, namely the classic habituation pattern and a sensitivity to the size of the deviation. The PDR decrement to a repeated standard sound, recovery to a deviant sound, and dishabituation to the re-presentation of the standard were assessed for small and large deviations embedded in irrelevant auditory sequences. The PDR not only showed habituation and dishabituation, but also recovered in correspondence with the magnitude of the acoustic deviation. This consistency between variations of the PDR and orienting response's properties indicates that the PDR is a valid index of the auditory orienting response.

A reconfigurable polarization antenna includes a microwave dielectric substrate having a ground plane that has a centrally located slot with five conducting patches, four of which form an evenly spaced apart perimeter group with a gap between each and the fifth, centrally positioned conducting patch. A conducting pad is positioned in each gap and is connected via a switch to the ground plane. A microstrip feed line including a short stub is positioned on the opposite side of the substrate and electromagnetically coupled to the slot. The polarization of the antenna is reconfigured by a selection of an on or off state of each of said switches.

The next generation of Navy ships will incorporate the latest in advanced electronics, weapon systems and antenna aperture structures to support the future needs of the Navy. Phased array antennas are typically comprised of 1000's of elements and are able to electronically steer multiple beams throughout a prescribed sector to provide both search and targeting information. This very timely information is usually integrated with other systems onboard a platform for use in situation awareness. Currently, without proper and frequent calibration, signal errors from environmental fluctuations and component aging result in diminished performance of the array. Due to the complex and dynamic nature of these active aperture systems, real-time system calibration will be required to maintain the ability to operate at the high level of performance necessary to carry out a platform mission. A collaborative effort between the Radar Division and Optical Sciences Division of the U.S. Naval Research Laboratory has successfully demonstrated a system with performance suitable for in-situ, real-time calibration of shipboard phased array antennas., The original document contains color images.

The U.S. Navy uses both military and commercial satellites for communication purposes. In the existing shipboard communications system, a separate antenna, most likely a reflector antenna, is used to communicate with each satellite. In the future, it is expected that these reflector antennas will be replaced by multi-function, low RCS (radar cross section) phased array antennas. In this report, we have designed (based on an existing method suggested by Amitay and Gans) a unique concept in which a single planar array (on a mobile earth station) can be used to communicate simultaneously with several geostationary satellites by generating multiple independent beams. These beams will need to be scanned in only one plane, thus reducing the number of phase shifters required for each beam. In the orthogonal plane, one or two hard-wired squints will be used to fix the beam position. This method will help to reduce the cost and complexity of phased array antennas on mobile earth stations., The original document contains color images.

Understanding the propagation of RF energy in confined naval shipboard environments is extremely important to the operability and effectiveness of communication systems used by the Navy. Single-frequency communication systems are known to suffer from multipath interference that can render them ineffective in confined spaces. Spread-spectrum and frequency-hopping systems, currently used in wireless local area networks (LANs), have been shown to operate effectively in confined shipboard environments in the absence of other RF signals. However, the transfer characteristics of these signals relative to bulkheads, watertight doors, ducts, mast cable transits, compartment penetrations and obstructions, and steel deck plates are not well characterized. Also, the complex interactions of communication signals with competing RF signals are not well understood for confined ship spaces. To address these issues for systems between 800 MHz and 3 GHz, a broadband bistatic measurement system was designed, and initial measurements were taken on the ex-USS Shadwell (23-25 February 1998) in Mobile, Alabama. More than 100 sets of data were collected for various open/closed door configurations on three levels of the ex-USS Shadwell. The measurement system and the measurements are discussed. Initial observations indicate that received power levels over reasonably long propagation distances were sufficient to ensure communication, even when all closures were set.