Study of blood flow sensing with microwave radiometry

A study and experimental investigation has been performed to determine the feasibility of measuring regional blood flow and volume in man by means of microwave radiometry. An indication was expected of regional blood flow from measurement of surface and subsurface temperatures with a sensitive radiometer. Following theoretical modeling of biological tissue, to determine the optimum operating frequency for adequate sensing depth, a sensitive microwave radiometer was designed for operation at 793 MHz. A temperature sensitivity of of 0.06 K rms was realized in this equipment. Measurements performed on phantom tissue models, consisting of beef fat and lean beefsteak showed that the radiometer was capable of sensing temperatures from a depth between 3.8 and 5.1 cm. Radiometric and thermodynamic temperature measurements were also performed on the hind thighs of large dogs. These showed that the radiometer could sense subsurface temperatures from a depth of, at least, 1.3 cm. Delays caused by externally-generated RF interference, coupled with the lack of reliable blood flow measurement equipment, prevented correlation of radiometer readings with reginal blood flow. For the same reasons, it was not possible to extend the radiometric observations to human subjects

Bio-Inspired, Odor-Based Navigation

The ability of moths to locate a member of the opposite sex, by tracking a wind-borne plume of odor molecules, is an amazing reality. Numerous scenarios exist where having this capability embedded into ground-based or aerial vehicles would be invaluable. The main crux of this thesis investigation is the development of a navigation algorithm which gives a UAV the ability to track a chemical plume to its source. Inspiration from the male moth\u27s, in particular Manduca sexta, ability to successfully track a female\u27s pheromone plume was used in the design of both 2-D and 3-D navigation algorithms. The algorithms were developed to guide autonomous vehicles to the source of a chemical plume. The algorithms were implemented using a variety of fuzzy controllers and ad hoc engineering approaches. The fuzzy controller was developed to estimate the location of a vehicle relative to the plume: coming into the plume, in the plume, exiting the plume, or out of the plume. The 2-D algorithm had a 60% to 90% success rate in reaching the source while certain versions of 3-D algorithm had success rates from 50% to 100%

An Analysis of Presence and User Experiences Over Time

This manuscript presents the result of a series of studies intended to shed light on understanding how trends regarding user experiences in VR changes over time when engaging with VR games. In my first study, I explored how user experiences compared when playing Minecraft on the desktop against playing Minecraft within an immersive virtual reality port. Fourteen players completed six 45 minute sessions, three sessions were played on the desktop, and three in VR. The Gaming Experience Questionnaire, i-Group presence questionnaire, and Simulator Sickness Questionnaire were administered after each session, and players were interviewed at the end of the experiment. Survey data showed substantial increases in presence and positive emotions when playing Minecraft in VR while multiple themes emerged in participant interviews: participants\u27 heightened emotional experiences playing Minecraft in VR was closely linked to feelings of immersion and improved sense of scale; participants overall enjoyed using motion controls, though they felt indirect input was better for some actions; and players generally disliked traveling via teleportation, as they found it disorienting and immersion-breaking. In my second study, I identified temporal shifts in user perceptions that had taken place within the first two years that consumer VR devices had become available. To consider what could be learned about the long-term use of consumer VR devices, I analyzed online forums discussions devoted to specifically VR. I gathered posts made on the /r/Vive subreddit from the first two years after the HTC Vive\u27s release. Over time, users moved from passive to active as their attitudes and expectations towards presence and simulator sickness matured. The significant trends of interest found to influence this was game design implementation and locomotion techniques. In my third study, again, I examined the data taken from the /r/Vive subreddit forum posts to gain further insights into the scope of what ``lingering effects\u27\u27 users had reported experiencing after using VR and the progression of these effects over time. After identifying search terms designed to discover comments made about lingering effects, I found three significant categories of lingering effects (besides simulator sickness) during my qualitative analysis: perceptual effects, behavioral effects, and changes in dreams. The perceptual and behavioral categories were further divided into sub-themes; including disruption of body ownership and proprioception, loss of a sense of depth in the real world, visual after effects, the need to verify the reality of the natural world through touch, hesitation when moving in the real world, and attempts to apply VR interaction metaphors to real-life interactions. After identifying these categories of effects, I mapped out how these effects progressed concerning time. In particular, I coded data according to four temporal concepts: 1) how long must be spent in VR to trigger an effect, 2) how long before the onset of an effect upon exiting VR, 3) the duration of any specific effect, and 4) the total duration that all effects can continue to occur overall. In my fourth study, I examined how user experiences and trends regarding presence changed throughout a single gaming session. Participants were immersed in a virtual experience called \u27The Secret Shop\u27 and given instructions to explore their surroundings with no guided direction. After their experience ended, users performed an After Action Review (AAR) while watching a recording of their recent experience, followed by a semi-structured interview. I graphed each user\u27s feelings of presence over time from second to second using the results of the After Action Review. Presence was shown in these graphs to both rise and fall, gradually and rapidly, throughout the course of each user\u27s experience. The analysis of both the graphs and the interviews then showed that presence was significantly impacted by user expectations, affordance inconsistencies, and the intensity of engagement experienced throughout the session. In my final study, I loaned out VR headsets to local novice users to track their perceptions of presence across the span of four weeks. Users were given the freedom to explore any VR games and applications of interest to them off-site to simulate regular VR consumer experiences. In this study, I analyzed how over time, novice users gradually evolved in their understanding of presence and what became most important to them in order to maintain and create it in the form of visual appeal, interaction techniques, and locomotion. I also found that the levels of engagement experienced across games were shown to be linked to whether users experienced lingering effects, how their perceptions of time spent within VR had been altered, and whether or not they retained any interest in investing in future VR-related purchases

Degradation by the atmosphere of microwave radiometric observations from space - 0.5 to 20 GHz, volume 2 Final report

Brightness temperatures and emissivities of sea wate

Lingering effects associated with the consumer use of virtual reality

Since the release of the Oculus Rift CV1 in 2016, millions of VR headsets have made their way into consumers’ homes. Since then, users have created large quantities of data about their experiences in VR through posts made to online discussion forums. We examine this data to gain insights on what sorts of “lingering effects” users report having experienced after VR, and on the progression of these effects over time. We found three major categories of lingering effects (besides simulator sickness) during our qualitative analysis: perceptual effects, behavioral effects, and changes in dreams. The perceptual and behavioral categories were further divided into sub-themes: disruption of body ownership and proprioception, loss of a sense of depth in the real world, visual aftereffects, the need to verify the reality of the real world through touch, hesitation when moving in the real world, and attempts to apply VR interaction metaphors to real life interactions. Users were nearly unanimous that these lingering effects only occurred after spending at least 1 h in VR, and that these effects completely disappeared several weeks after they first appeared (assuming the user continued to spend time in VR). There was less agreement about how long these effects lasted after exiting a specific VR session. The results of our analysis suggest that users feel that there are no long-term side effects to the use of VR. We pair this analysis with an analysis of interviews conducted with 20 novice users who were loaned Oculus Quest HMDs to use for 4 weeks. Semi-structured interviews with participants further substantiated the findings of our analysis of online discussions

Conflict Resolution in the Assignment of Area Entitlements for Seabed Mining

This Article examines the conditions creating a need for, and the procedures being implemented to achieve, resolution of conflicts over deep seabed areas sought for exclusive exploration entitlements. The author argues that if and when deep seabed mining takes place, certain tangible advantages will accrue to nations or organizations that have obtained entitlements to exclusivity of activity within areas of the seabed. The author further suggests that the development of legal assurances of exclusivity and security of work within a claimed area has been proceeding along two different tracks, the 1982 Convention, and a prospectively complementary but currently separate and potentially competing entitlement system based on domestic laws, multilateral arrangements, and private agreements. The author argues that successful resolution in either track could facilitate progress in the other, and arrangements developed through efforts in the separate tracks could contribute eventually to a convergence of the two legal regulatory regimes

HEY LARRY! INVESTIGATING INTERRUPTIONS IN FUTURE VERTICAL LIFT PLATFORMS

Using technology to improve human performance is critical to maximizing the benefits of future combat systems. This study explores the effects of interruptions during high and low cognitive load states when completing dynamic tasks. Furthermore, it provides insight into how to integrate artificial intelligence and virtual assistants into future aircraft effectively. This research and the following analysis provided the Holistic Situation Awareness and Decision Making (HSA-DM) program office with meaningful data and recommendations that will enable them to reduce the impact of interruptions while improving the performance of future pilots. Specifically, this study collected and examined heart rate variability, subjective cognitive load, flight metrics, interruption lag, and task resumption lag while participants piloted an aircraft and performed dynamic tasks in a flight simulator. There were three different modalities used to assist participants with completing interrupted tasks while performing their primary task. The research team determined that the tactile activated artificial intelligence was the most effective at reducing total interruption time while having the smallest effects on flight performance and cognitive load.Major, United States ArmyMajor, United States ArmyCaptain, United States ArmyCaptain, United States ArmyCaptain, United States ArmyApproved for public release. Distribution is unlimited

Underwater Video as a Tool to Quantify Fish Density in Complex Coastal Habitats

Habitat loss is a serious issue threatening biodiversity across the planet, including coastal habitats that support important fish populations. Many coastal areas have been extensively modified by the construction of infrastructure such as ports, seawalls, docks, and armored shorelines. In addition, habitat restoration and enhancement projects often include constructed breakwaters or reefs. Such infrastructure may have incidental or intended habitat values for fish, yet their physical complexity makes quantitatively sampling these habitats with traditional gears challenging. We used a fleet of unbaited underwater video cameras to quantify fish communities across a variety of constructed and natural habitats in Perdido and Pensacola Bays in the central northern Gulf of Mexico. Between 2019 and 2021, we collected almost 350 replicate 10 min point census videos from rock jetty, seawall, commercial, public, and private docks, artificial reef, restored oyster reef, seagrass, and shallow sandy habitats. We extracted standard metrics of Frequency of Occurrence and MaxN, as well as more recently developed MeanCount for each taxon observed. Using a simple method to measure the visibility range at each sampling site, we calculated the area of the field of view to convert MeanCount to density estimates. Our data revealed abundant fish assemblages on constructed habitats, dominated by important fisheries species, including grey snapper Lutjanus griseus and sheepshead Archosargus probatocephalus. Our analyses suggest that density estimates may be obtained for larger fisheries species under suitable conditions. Although video is limited in more turbid estuarine areas, where conditions allow, it offers a tool to quantify fish communities in structurally complex habitats inaccessible to other quantitative gears

Using Wildlife as Receptor Species: A Landscape

To assist risk assessors at the Department of Energy’s Savannah River Site (SRS), a Geographic Information System (GIS) application was developed to provide relevant information about specific receptor species of resident wildlife that can be used for ecological risk assessment. Information was obtained from an extensive literature review of publications and reports on vertebrate- and contaminant- related research since 1954 and linked to a GIS. Although this GIS is a useful tool for risk assessors because the data quality is high, it does not describe the species’ site-wide spatial distribution or life history, which may be crucial when developing a risk assessment. Specific receptor species on the SRS were modeled to provide an estimate of an overall distribution (probability of being in an area). Each model is a stand-alone tool consisting of algorithms independent of the GIS data layers to which it is applied and therefore is dynamic and will respond to changes such as habitat disturbances and natural succession. This paper describes this modeling process and demonstrates how these resource selection models can then be used to produce spatially explicit exposure estimates. This approach is a template for other large federal facilities to establish a framework for site-specific risk assessments that use wildlife species as endpoints