New sensor and display technologies are expected to enhance the performance of soldiers by providing them more information about the battlefield. However, there is concern that greater quantities of information and increases in mental workload might cause distraction, reduce attention to dangers in the immediate environment, and threaten soldier survival. The purpose of this laboratory investigation was to quantify the effects of increases in mental workload on one of the soldier's most basic tasks --- avoiding ground hazards while walking. The participants were 12 U.S. Army infantry soldiers. The study was conducted on a treadmill that was modified to provide the participants a view of impending ground hazards up to 5 meters forward of their walking position. The study was a 2X3 fixed factor design with two levels of terrain difficulty (No Hazards and Hazards) and three levels of mental workload (No Load, Moderate load, and High load), all as within-subject effects. Mental workload was increased from the "No Load" to a "Moderate" level by requiring the participants to perform a mental arithmetic task while walking. Mental workload was increased from the "Moderate" to the "High" level of load by increasing the difficulty of arithmetic problems. The dependent variables included time and error in the performance of the mental arithmetic task, the mean and standard deviation in step length and step rate, the number of ground hazards contacted, and subjective ratings of workload. The participants" scores on the Armed Forces Qualification Test (AFQT) and subtests of the Armed Services Vocational Aptitude Battery (ASVAB) related to arithmetic skills were also obtained. The results of the investigation indicated that when the participants were required to avoid hazards, step length decreased and step rate increased, as was expected. Both measures of gait increased in variability. Subjective ratings of physical demand and effort obtained across the three levels of mental workload increased significantly, along with perceptions of workload associated with a perceived decline in performance. Subjective ratings obtained across the two levels of terrain difficulty indicated that ratings of mental demand and effort increased with each increase in level of mental workload. When the participants were confronted with the more difficult arithmetic problems at the "High" level of mental workload, time and error in performing the mental arithmetic task increased as did ratings of temporal demand, frustration, and workload attributable to a perceived decline in performance; however, subjective ratings of physical demand decreased. Interactions found between terrain difficulty and mental workload indicated that differences in ratings of performance and overall workload scores between the two levels of terrain difficulty decreased significantly between the "No Load" and the "Moderate" level of mental workload, and converged at the "High" level of mental load. Although relationships were found between perceived workload, gait, and performance of the mental arithmetic and hazard avoidance tasks, the analysis did not reveal a significant effect of mental workload on the number of hazards contacted. Some participants tended to contact more hazards at the "High" level of mental workload than at the "No Load" or the "Moderate" levels, as expected. However, other participants tended to contact more hazards at the "Moderate" level of mental load than at either of the two extremes. Still other participants tended to contact more hazards at the "No Load" level of mental workload than at the "Moderate" or the "High" levels. Correlations were found between subjective ratings of workload, mental arithmetic performance, and scores on the AFQT and subtests of the ASVAB related to arithmetic skills, but no relationships were found between test scores and performance of the hazard avoidance task. However, when test scores were used as covariates in the analysis of mental arithmetic performance, the findings revealed that the number of correct responses to the arithmetic problems decreased when the participants were required to avoid hazards. The results of the study may support the belief that the allocation of limited resources will vary based on past experience and other individual differences, and that the amount of resources allocated to a task may be influenced by the difficulty of the task, criteria for performance, and the motivation of the individual. / Master of Science

Typical algorithms for processing unresolved space imagery from optical systems make broad assumptions about the expected behavior of the sensors during collection. While these techniques are often successful at data reduction for a particular mission, they rarely extend to sensors in different operating modes. Such specialized techniques therefore reduce the number of sensors able to contribute imagery. By approaching this problem with analysis of the fundamental dynamic equations and geometry at play, we can gain a deeper understanding into the behavior of both stars and space objects viewed through optical sensors. This type of analysis has the potential to enable data collection from a wider variety of sensors, increasing both the quantity and quality of data available for space object catalog maintenance. This dissertation will explore the implications of this approach to unresolved data processing. Sensor-level motion descriptions will be derived and applied to the problem of space object discrimination and tracking. Results of this processing pipeline as applied to both simulated and real optical data will be presented. / Ph. D.

Approved for public release, distribution is unlimited / Due to the rapid development of technology, many simple tasks can now be automated, leaving more difficult and cognitive tasks such as planning, decision making and design to teams. Technology also allows these teams to be distributed through time and space. While this is becoming more and more prevalent in the business world, distributed teams also exist in the military where the stresses are much different. One of the key factors associated with collaboration in military teams is situational awareness. This research used a commercial command and control type video game to investigate the issues of collaboration and situational awareness. The amount of information subjects had access to was varied to see if there was a significant impact upon their level of situational awareness which was measured by the accuracy of maps that the subjects drew. Results from this research may provide insight into how much information is needed by distributed teams and when they need it. Ideas for future research in this area have also been proposed. / Lieutenant Commander, United States Navy

<p>    </p> <p>Space has become ever more crowded since the launch of Sputnik. The need for predictions of possible collisions between space objects has only ever grown. The development of space, particularly around Earth, increases the density of space objects and skyrockets the number of close approaches between these objects, called conjunctions. This investigation is conducted in the context of probability dilution, a phenomenon leading to a false negative collision prediction where increasing positional uncertainty decreases the predicted likelihood of a collision. Dilution is investigated along two avenues: how to generate accurate collision predictions in an efficient manner and how to obtain better input data with which to make these predictions. Along the first avenue, this research presents a novel analytical rectan- gular probability of collision expression as well as a variety of new covariance scale factor formulations for maximum collision probability that indicate the maximum possible collision risk for any conjunction. Along the second avenue, this research tests new sensor tasking regimes to mitigate dilution, ultimately showing that while dilution can be reduced, shrink- ing the positional covariance through optimal measurement updates may not be enough to avoid false negatives in orbital conjunctions. </p>

<p dir="ltr">Characterizing unknown space objects is an important component of robust space situational awareness. Estimating the shape of an object allows analysts to perform more accurate orbit propagation, probability of collision, and inference analysis about the object’s origin. Due to the sheer distance from the camera combined with diffraction and atmospheric ef- fects, most resident space objects of interest are unresolved when observed from the ground with electro-optical sensors. State of the art techniques for object characterization often rely on light curves — the time history of the object’s observed brightness. The brightness of the object is a function of the object’s shape, material properties, attitude profile, as well as the observation geometry. The process of measuring real light curves is complex, involv- ing the physics of the object, the sensor, and the background environment. The process of recovering shape information from brightness measurements is known as the light curve shape inversion problem. This problem is ill-posed without further assumptions: modern direct shape inversion methods require that the attitude profile and material properties of the object is known, or at least can be hypothesized. This work describes improvements to light curve simulation that faithfully model the environmental and sensor effects present in true light curves, yielding synthetic measurements with more accurate noise characteris- tics. Having access to more accurate light curves is important for developing and validating light curve inversion methods. This work also presents new methods for direct shape inver- sion for convex and nonconvex objects with realistic measurement noise. In particular, this work finds that improvements to the convex shape inversion process produce more accurate, sparser geometry in less time. The proposed nonconvex shape inversion method is effective at resolving singular large concave feature.</p>

<p dir="ltr">With the increase in planned space missions in cislunar space, it is necessary to study the ability of observers to observe and track objects in this regime. This thesis focuses on creating a sensor tasking algorithm for constellations of optical observers to efficiently observe cislunar objects. The circular restricted three body problem is used for the dynamics of the objects while the bi-circular restricted four body problem is used to approximate the position of the sun.</p><p dir="ltr">A new way of discretizing the field of regard is proposed that respects the observers field of view on the unit sphere. A method for providing feedback to the observer in a delayed feedback environment is applied to mean state, single Gaussian, and particle representations of uncertainty. The method of determining a scaling coefficient for Sanson’s probability of detection is recorded. Sanson’s probability of detection is studied for determining the correct effective aperture dimensions of an optical observer. An approximation is presented for expediting calculations of Sanson’s probability of detection. An uncertainty propagation analysis shows there is an efficient number of particles to use for particle uncertainty far below the required number for a full Monte Carlo particle uncertainty representation. </p><p dir="ltr">Mean state, single Gaussian and particle methods of uncertainty characterization are compared in a cislunar simulation showing the benefits of the particles solution over other forms of uncertainty characterization. Particles are not only an effective uncertainty representation in a delayed feedback environment, they are computationally feasible for the sensor tasking problem. The performance of the particle algorithm for a constellation of observers is evaluated in a simulated small satellite breakup in a Lyapunov orbit and a simulated breakup of the proposed Lunar Gateway. The performance of observers in direct retrograde, low lunar, geosynchronous, and northern Halo orbits are evaluated in the breakup simulations. Results from these simulations show that observers in low lunar and Halo orbits can be valuable observation standpoints in breakups around the near-Moon region of cislunar space.</p>

Vehicular Ad hoc Networks (VANETs) are a particular form of wireless network made by vehicles communicating among themselves and with roadside base stations. A wide range of services has been developed for VANETs ranging from safety to infotainment applications. A key requirement for such services is that they are offered with Quality of Service (QoS) guarantees in terms of service reliability and availability. Furthermore, due to the openness of VANET’s wireless channels to both internal and external attacks, the application of security mechanisms is mandatory to protect the offered QoS guarantees. QoS routing plays an essential role in identifying routes that meet the QoS requirements of the offered service over VANETs. However, searching for feasible routes subject to multiple QoS constraints is in general an NP-hard problem. Moreover, routing reliability needs to be given special attention as communication links frequently break in VANETs. To date, most existing QoS routing algorithms are designed for stable networks without considering the security of the routing process. Therefore, they are not suitable for applications in VANETs. In this thesis, the above issues are addressed firstly by developing a link reliability model based on the topological and mathematical properties of vehicular movements and velocities. Evolving graph theory is then utilised to model the VANET communication graph and integrate the developed link reliability model into it. Based on the resulting extended evolving graph model, the most reliable route in the network is picked. Secondly, the situational awareness model is applied to the developed reliable routing process because picking the most reliable route does not guarantee reliable transmission. Therefore, a situation-aware reliable multipath routing algorithm for VANETs is proposed. Thirdly, the Ant Colony Optimisation (ACO) technique is employed to propose an Ant-based multi-constrained QoS (AMCQ) routing algorithm for VANETs. AMCQ is designed to give significant advantages to the implementation of security mechanisms that are intended to protect the QoS routing process. Finally, a novel set of security procedures is proposed to defend the routing process against external and internal threats. Simulation results demonstrate that high levels of QoS can be still guaranteed by AMCQ even when the security procedures are applied.

Each year the number of flights around the world increases, and to be able to counter the increase of traffic the air traffic control (ATC) and the systems they use to control the traffic must be developed in the same pace. This is something that bigger ATCC’s around the world has gone through and experienced. To be able to maintain or increase the level of safety at the same time as the traffic load increases, you need to do more than just hire more air traffic controllers. The systems in use must always be developed in accordance to new regulations and as well become more effective. This leads to ATCC’s continuously going through changes in the form of implementations of new ATC systems. The research and development are moving forward in an immense speed, and the latest decade’s ATC in many places has gone from writing down information on paper strips to the more modern strip less systems. This has resulted in a remarkable increase of effectivity and safety in ATC. In Sweden, there are three bigger ATCC’s: Stockholm ATCC, Malmö ATCC and ÖKC. In both Stockholm and Malmö, the strip less systems are already in use while ÖKC uses a less developed ATC system. It is economically demanding to continuously keep the ATCC’s up to date with the most modern systems, and the controlling factor is demand. In a working environment where safety is of the highest concern, you need a carefully prepared method of both updating, implementing, and testing new systems, providing personnel with training and sequentially implementing it. To achieve this, you need to do thoroughly review the concerned ATCC before, during and after an implementation. With the help of interviews, surveys and literature studies the working methods and processes have been examined and analyzed on ÖKC. By gathering opinions from the personnel at ÖKC, a good understanding of ÖKC has been attained. The unique thing about ÖKC’s air traffic, compared to the other ATCC’s, is that a big portion of their air traffic is military flights, which leads to different traffic situations. This study has been conducted as a first step before an implementation, with the intention of analyzing how a strip less system affects ÖKC with its current working methods and processes, and the connection to situational awareness. The study intends to be used as a foundation to future inquiries of how ÖKC will be affected by an implementation of this kind. It also contains opinions from operative personnel at ÖKC, and how they feel about a change of an ATC system.

Approved for public release; distribution is unlimited / This study compares the effects of a visual and a 3-dimensional auditory display on primary and secondary task performance, mood, and mental workload at incremental levels of sleep deprivation. It is based on a study conducted by the Army Research Laboratory, Cognitive Science Branch, Aberdeen, Maryland, from 12 Marines performing land navigational tasks in two helmet-mounted display (HMD) modes; visual and 3-dimensional auditory, for a 48 hour period. The results indicate that performance under sleep deprivation is significantly impacted in both modalities; however, performance in the primary task was more degraded in the 3-D auditory modality. Additionally, Marines were more likely to experience degraded performance in the secondary task with increased sleep deprivation. The recommendations address the need to design HMDs that will not overburden sensory channels and the concern for military leaders to understand the additional demands imposed on solders in a HMD environment. / Captain, Signal Corps, United States Army

CHDS State/Local / The availability and interoperability of communications at an incident scene have long been recognized as high-priority problems that need to be addressed to improve our nation's Homeland Security and preparedness. This thesis describes a proposed methodology to address these issues at the Incident Command level while enhancing situational awareness and information sharing. The thesis analyzes the results of a research project funded by the Department of Homeland Security at the University of Louisville's IT Research Center for Homeland Security. The problem being addressed is that the decision-maker with the boots on the ground, the Incident Commander, needs relevant information in the early stages of the emergency at the incident scene and an efficient way to communicate with other resources. The research project fielded a prototype solution based on readily available commercial off-the-shelf components integrated in a man-portable configuration to provide maximum flexibility, lower costs, and ease of operations. A proposed concept of operations in various prevention and response environments was also recommended in the thesis after analyzing the results of several field exercises and interviews with users. / Director, Information Technology Resource Center, University of Louisville