A key obstacle for training an autonomous agent in real air-to-air combat is the lack of available training data, which makes it difficult to apply supervised learning techniques. Self-play is a method that can be used where an agent trains against itself or against versions of itself without imitation data or human instruction. Agents training only against themselves learn brittle strategies that do not generalize very well, which is why training against a distribution of strategies is necessary to improve robustness. In this thesis, we study two problems. First, what is a robust strategy, and how do we evaluate it? Secondly, how do we increase the robustness of strategies learned in a self-play setting by adapting the training distribution? The problems are significant to study because self-play is a very promising method of training not only for air combat but in any non-cooperative problem setting where a simulator can be used to gather training data with no human in the loop. Specifically, in the aircraft industry, the cost of gathering samples is incredibly high. To evaluate the robustness of a population of strategies we turned to evolutionary game theory and connected theα-rank algorithm to what we perceive as robustness. Theα-rank induces a strict ordering over the set, which we then take as an evaluation of the robustness of the strategies. We validated that a highα-rank correlated well with performing well in an out of population evaluation. To study how the robustness of a population correlated with training distributions, we trained populations against four different training distributions. We used the uniform, δ-uniform, andα-rank distributions that rely on no information, information on the training process, and information on the robustness of agents, respectively. We also designed a novel amortizedα-rank training distribution that combines the information behind the δ-uniform and α-rank distributions, and we showed that it induced superior robustness properties in the learned strategies. Our efforts indicate that even better training distributions can be produced, which is useful when looking at using self-play in the future. / Ett stort hinder vid träning av en autonom agent för riktig luftstrid är bristen på träningsdata vilket gör det svårt att applicera övervakad inlärning. Självspelande är en metod där agenter tränar mot sig själva eller mot versioner av sig själva utan tillgång till data att imitera och utan mänsklig instruktion. Agenter som tränar enbart mot sig själva lär sig dock sköra strategier som inte generaliserar tillräckligt väl. Därför krävs träning mot en distribution av strategier för att en agent ska kunna bli robust. I denna uppsats studerar vi två problem. Ett, vad är en robust strategi och hur utvärderar vi den? Två, hur ökar vi robustheten hos strategier som tränats fram via självspelande genom att anpassa träningsdistributionen? Problemen är relevanta att studera på grund av att självspelande är en lovande metod som kan användas inte bara för luftstrid utan för ett brett spektrum av icke-kooperativa problemområden där en simulator kan användas för att genomföra datainsamling utan en människa i loopen. Speciellt inom flygplansindustrin är kostnaden för insamling av riktig träningsdata extremt hög. För att utvärdera robustheten i en population av strategier vände vi oss tillevolutionär spelteori och koppladeα-rank-algoritmen till vad vi uppfattar som robusthet.α-rank, som vi tolkar som en utvärdering av robusthet, induceraren strikt ranking över en mängd av strategier. Vi validerade att en högα-rankkorrelerade väl med goda resultat vid en utvärdering av strategierna i en annan population. För att studera hur robustheten i en population korrelerade med användandet av olika träningsdistributioner tränade vi populationer mot fyra olika tränings-distributioner. Vi använde den uniforma distributionen, den δ-uniforma distributionen ochα-rank-distributionen, som baseras på ingen information, information om träningsprocessen respektive information om agenternas robusthet. Videsignade även en amorteradα-rank-distribution, som kombinerar informationen bakom den δ-uniforma distributionen ochα-rank-distributionen, och vi visade att träning mot den nya distributionen resulterade i mer robusta strategier. Våra resultat indikerar att det är möjligt att skräddarsy ännu bättre träningsdistributioner, vilket är användbart när vi tittar på att utnyttja själv-spelande i högre grad i framtiden.

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Most of the navigation systems used in today’s aircraft rely on Global Navigation Satellite Systems (GNSS). However, GNSS is not fully reliable. For example, it can be jammed by attacks on the space or ground segments of the system or denied at inaccessible areas. Hence to ensure successful navigation it is of great importance to continuously be able to establish the aircraft’s location without having to rely on external reference systems. Localization is one of many sub-problems in navigation and will be the focus of this thesis. This brings us to the field of visual odometry (VO), which involves determining position and orientation with the help of images from one or more camera sensors. But to date, most VO systems have primarily been established on ground vehicles and low flying multi-rotor systems. This thesis seeks to extend VO to new applications by exploring it in a fairly new context; a fixed-wing piloted combat aircraft, for vision-only pose estimation in applications of extremely large scene depth. A major part of this research work is the data gathering, where the data is collected using the flight simulator X-Plane 11. Three different flight routes are flown; a straight line, a curve and a loop, for two types of visual conditions; in clear weather with daylight and during sunset. The method used in this work is ORB-SLAM3, an open-source library for visual simultaneous localization and mapping (SLAM). It has shown excellent results in previous works and has become a benchmark method often used in the field of visual pose estimation. ORB-SLAM3 tracks the straight line of 78 km very well at an altitude over 2700 m. The absolute trajectory error (ATE) is 0.072% of the total distance traveled in daylight and 0.11% during sunset. These results are of the same magnitude as ORB-SLAM3 on the EuRoC MAV dataset. For the curved trajectory of 79 km ATE is 2.0% and 1.2% of total distance traveled in daylight and sunset respectively.  The longest flight route of 258 km shows the challenges of visual pose estimation. Although it is managing to close loops in daylight, it has an ATE of 3.6% during daylight. During sunset the features do not possess enough invariant characteristics to close loops, resulting in an even larger ATE of 14% of total distance traveled. Hence to be able to use and properly rely on vision in localization, more sensor information is needed. But since all aircraft already possess an inertial measurement unit (IMU), the future work naturally includes IMU data in the system. Nevertheless, the results from this research show that vision is useful, even at the high altitudes and speeds used by a combat aircraft.

The goal of this work has been to develop a design suggestion of a visualization system that supports training instructors and air force units during After Action Reviews (AAR) in training at the Swedish Air Force Combat Simulation Center (FLSC). The suggestion was developed through a design study consisting of interviews, a demonstration and a design workshop in parallel with an iterative prototyping process. The study resulted in a visualization system that indicates enemy aircraft at threatening distances to support identification of critical situations. To support the following threat assessment, visualizations that automatically present radar lock-on information and missile envelopes are suggested. Although radar lock-on information and missile envelopes has been presented in earlier visualizations they have not been adapted to the mode of operations of the AAR. Adapting the visualizations to the AAR would make the threat assessment easier and more effective to conduct. The purpose of the visualization is to make it easier for training instructors and air force units with limited experience of simulation training to conduct a high quality AAR through emphasizing relevant situations and points of interest.

The attrition rate of enlistees in basic combat training is of particular concern to all Branches of the military due to the high cost associated with recruiting and training a new enlistee. Each year the military loses hundreds of millions of dollars invested in enlistees whom never make it to their first duty station. Investigators have extensively examined the impact of physiological injuries on the rate of enlistee discharge from basic combat training. Also, investigators have reported that alcoholism, adjustment disorders, mood disorders, and personality disorders were among the leading hospital discharge diagnostic categories for enlistees during the 1990s; especially, within the first six-months of service. Additionally, investigators have reported that the transition process from civilian to military in basic combat training tends to be very stressful and anxiety provoking for enlistees. However, little data has been gathered to assess the relationship of enlistees' physiological and perceived stress levels and their attrition rate. A study was conducted of 155 soldiers during their nine-week basic combat training at Fort Jackson, South Carolina. Salivary amylase testing was used as an objective measure of physiological stress, and the Multiple Affects Adjective CheckList Revised (MACCL-R) was use as a subjective measure of perceived stress. It was hypothesized that enlistees with higher levels of stress would also have a higher level of depression and hostility resulting in performance degradation. The results of linear regression analyses and multivariate pairwise correlation showed a statistically significant positive relationship among perceived stress, hostility and depression levels. Additionally, the analyses showed that for the soldiers participating in this study, coping style moderated their perceived stress experience. Those participants who were able to modify their coping mechanism to meet the physically and mentally demanding challenges of basic combat training tended to be more confident in successfully completing training. Moreover, they were less likely to receive disciplinary action. The military training command has requested follow up studies to expand upon this current study to encompass the various training cycles over a one-year time period. / Ph. D.

As falls and fall-related injuries are a major cause of injuries, the purpose of this study was to investigate whether, and to what extent, the stage combat fall technique training could reduce the impact forces of falls from standing. Twenty-six healthy young adults (14 males and 12 females) participated in our study, and were randomly assigned to either a training group or non-training (control) group. Both groups completed a pre-intervention and a post-intervention fall testing session, separated by two weeks, in which they performed naturalistic falls. The training group performed identical pre-intervention fall testing as the control group, and was then required to receive four 1-hour training sessions in the course of two weeks, led by a certified stage combat fall technique training instructor. The training group then completed a post-intervention fall testing session where they performed naturalistic falls and also falls using the fall technique they learned. Falls were induced in both forward and backward directions using a tether-release protocol. Differences between control and training groups at pre-training, and group differences in the change in dependent measures with training, were examined using Mann-Whitney U tests. The results showed that, following stage-combat fall training, the training group exhibited 32% and 35% reduction in median impact forces for forward and backward falls respectively, while the control group exhibited 5% and 2% reductions (p = 0.002 and <0.001). In addition, the training group showed shorter backward fall duration as well as longer impact time, larger impulse, and longer or larger center-of-pressure based measures for both directions of falling than the control group. However, training was not associated with reduced impact force during the naturalistic falls of the training group. To our knowledge, this was the first study to investigate the stage combat fall technique training and demonstrate its effectiveness as an intervention to reduce impact forces of falls, thereby exploring the potential to reduce the number of fall-related injuries. While these falls were induced from standing, whether these results would transfer to an unanticipated fall while walking due to a slip/trip remain to be explored. / Master of Science / As falls and fall-related injuries are a major cause of injuries, the purpose of this study was to investigate whether, and to what extent, the stage combat fall technique training could reduce the impact forces of falls from standing. Twenty-six healthy young adults (14 males and 12 females) participated in our study, and were randomly assigned to either a training group or non-training (control) group. Both groups completed a pre-intervention and a post-intervention fall testing session, separated by two weeks, in which they performed naturalistic falls. The training group was required to receive four 1-hour training sessions in the two-week intervention period, led by a certified stage combat fall technique training instructor. The training group then completed a post-intervention fall testing session where they performed naturalistic falls and also falls using the fall technique they learned. The results showed that, following stage-combat fall training, the training group exhibited nearly a 1/3rd reduction in impact forces for both forward and backward falls, while the control group only exhibited 5% and 2% reductions respectively. Our analysis also showed that the training group achieved this reduction in impact force by increasing the impact time and spreading out their bodies more, to distribute the impact over a larger area. To our knowledge, this was the first study to investigate the stage combat fall technique training and demonstrate its effectiveness as an intervention to reduce impact forces of falls, thereby exploring the potential to reduce the number of fall-related injuries.

Topic This study examines the hymnic pericopes found at Revelation 4.8-11; 5.9-14; 7.10- 12; 11.15-18; 12.10-12; 15.3,4 and 19.1-8 in light of the cosmic conflict theme. It considers that this theme is a major contributor to the development of Revelation’s plot, and thus the hymnic sections are informed by, and inform the understanding of the controversy. Purpose Recognizing that the majority of critical studies give interpretative primacy to the social and political realities that existed in the Roman Empire at the time of Revelation’s composition, there is need for an examination of the storyline from the perspective of issues that are clearly of narratival importance. This study argues that the cosmic conflict is at the center of the book’s concerns, and attempts to determine the function of the hymns in relation to the ongoing controversy. Previous examinations of the hymnic sections have either considered them to be a response and/or parody to Roman liturgy, examples of God’s unquestioned sovereignty, or expressions of thematic overtones found throughout the book. While all these approaches make a contribution to a greater understanding of the hymns, the relation of the hymns to the ever-present conflict theme has not been explored. This study allows the hymnic sections to engage with the larger narrative issue as to who is truly the rightful sovereign of the universe. Conclusion This study found that a close examination of the text confirms that the cosmic conflict is the major motif in the narrative, and that it does not simply serve as a metaphor for political realities. It also concluded that the temple/throne room imagery found throughout the storyline, should have a controlling influence upon interpretation. This setting provides the backdrop for understanding the origins and issues of the controversy. Another conclusion of the study is that the only way for the controversy to be resolved is for God to reveal Himself in such a manner that the truth about Him is manifest. Finally, it was seen that the hymns do provide commentary on the conflict, by acclaiming God’s goodness and right to rule, despite the undertones of Satan’s accusations. / New Testament / D. Th. (New Testament)

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper provides a current review of a new installed system test facility (ISTF) capability for the Air Force and Navy. The requirements, design characteristics, and status of the joint-service Communications, Navigation, Identification Simulator (CNIS) developments will be covered along with their relationships with the Air Force’s Avionics Test and Integration Complex (ATIC) and the Navy’s Air Combat Environment Test and Evaluation Facility (ACETEF) ISTFs. These developments provide the services an interactive spatially, temporally, and tactically coherent signal environment for development and operational test and evaluation. The Joint Communications Simulator (JCS) and Joint Data Link Simulator (JDLS) capabilities, integration aspects, and development schedules (2000 IOC) will also be addressed. Finally, installed system test and evaluation concepts, both Air Force and Navy, using the simulators will be previewed to assist upcoming development programs in identifying potential applications.