A quadrotor is an omnidirectional unmanned air vehicle that is suitable for indoor flight because of its ability to hover and maneuver in confined spaces. The remote operation of this type of vehicle is difficult due to a lack of sensory perception; typically, the view from the onboard camera is the only information transmitted to the pilot. This thesis proposes using force feedback exerted by the command input device on the hand of the pilot to assist in avoiding collisions while navigating in indoor environments. Five candidate algorithms are presented for calculating the forces to be felt by the pilot based on the quadrotor's position and velocity in the indoor environment. The candidates include a parametric algorithm based on the dynamics of the quadrotor, two time-to-impact algorithms, and two algorithms that employ virtual springs between the quadrotor and obstacles. A method of incorporating the position of the command input device to improve the usability and effectiveness of the algorithms is also presented. A framework for simulating the quadrotor dynamics, indoor environment, and force feedback algorithms is described. In the simulation, the pilot commands a simulated quadrotor, using a commercial haptic interface, as it flies in an indoor environment. The pilot receives force feedback cues as the quadrotor navigates around obstacles. Two methods of control were used for the simulation. In the first method, displacements of the haptic interface correspond to velocity commands to the quadrotor. In the second method, displacements of the input correspond to desired roll and pitch commands. Two user study experiments, one for each control method, were performed to compare the force feedback algorithms in simulation. The results of the velocity control experiment suggest that higher force levels help to avoid collisions and that the time to impact algorithm results in fewer collisions than having no force, but is not significantly better than the other algorithms. The results of the angle control experiment suggest that the time to impact algorithm is clearly the best in terms of hits and hit length and has no disadvantages compared to the other algorithms. Finally, to demonstrate the force feedback algorithms and software in a real-world environment, the system was interfaced with a physical quadrotor. The quadrotor system is described and the results of the tests are presented.

Coral terrace surveys and U-series ages of coral and mollusk shells yield a surface uplift rate of ~0.6 m/ka for Kisar Island. The small island is located NE of Timor in the active Banda Arc of Indonesia. Based on this rate, Kisar first emerged from the ocean as recently as ~450 ka. Terrace surveys show warping that follows a pattern of east-west striking folds, which are along strike of thrust-related folds of similar wavelength imaged by a seismic reflection profile just offshore. This deformation shows that the emergence of Kisar can be attributed to forearc closure along the south-dipping Kisar Thrust. Terrace morphology and coral ages are best explained by recognizing major terraces as mostly growth terraces and minor terraces as mostly erosional into older growth terraces. All reliable and referable coral U-series ages are marine isotope stage (MIS) 5e (118-128 ka), which encrusted the coast up to 60 m elevation. All coral samples are found below 6 m elevation, but a tridacna (giant clam) shell in growth position at 95 m elevation yields an age of 195 +/- 31 ka, which corresponds to MIS Stage 7. Loose deposits of coral fragments found on top of low terraces between 8 and 20 m elevation yield ages of < 100 years and may represent paleotsunami deposits from previously undocumented seismic activity in the region. The metamorphic rocks of Kisar, Indonesia, which correlate with the Aileu Metamorphic Complex of East Timor, record the breakup of a supercontinent with associated rifting, metamorphism from arc-continent collision, and the growth and exhumation of a new orogenic belt. The protoliths of these rocks are mostly psammitic with minor basaltic and felsic igneous rocks. Geochemical analyses of mafic meta-igneous rocks show rift affinities that are likely related to rifting of Gondwana and later breakup in the Jurassic Period. The Aileu Complex is overlain by younger sedimentary rocks deposited on the northern passive margin of Australia, which collided with the Banda Arc in latest Miocene time. This collision caused metamorphism of the distal edge of the continental margin rocks at conditions of 600-700°C at 6-8 kbar and up to 700-850°C at 8-9 kbar locally, corresponding to depths from 25 to 30 km. These rocks were then rapidly uplifted and exhumed. U-Pb analysis of detrital zircons indicates a Permian to Late Jurassic age of the sedimentary sources and confirm an Australian provenance. The timing of metamorphism of the Aileu Complex is poorly constrained by previous studies, of which only a white mica cooling age of 5.36 +/- 0.05 Ma proved reliable. Prior apatite fission track studies show that all tracks are partially to completely annealed suggesting recent rapid cooling. A domal geometry of the island above the sea floor is expressed in the pinnacle shape. Foliations on Kisar Island generally strike parallel to the coastline, which is may be suggestive of doming. The Kisar Thrust, which is imaged in offshore seismic reflection data, may indicate that the doming corresponds to diapirism into the hinge of an active thrust-related anticline or diapirism of buoyant continental material along the thrust itself.

Unmanned vehicle systems, specifically Unmanned Air Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs) have found potential use in both military and civilian applications. For many applications, unmanned vehicle systems are required to navigate in urban environments where obstacles with various types and sizes exist. The main contribution of this research is to offer vision-based path planning, collision avoidance, and target tracking strategies for Unmanned Air and Ground vehicles operating in urban environments. Two vision-based local-level frame mapping and planning techniques are first developed for Miniature Air Vehicles (MAVs). The techniques build maps and plan paths in the local-level frame of MAVs directly using the camera measurements without transforming to the inertial frame. Using a depth map of an environment obtained by computer vision methods, the first technique employs an extended Kalman Filter (EKF) to estimate the range, azimuth to, and height of obstacles, and constructs local spherical maps around MAVs. Based on the maps, the Rapidly-Exploring Random Tree (RRT) algorithm is used to plan collision-free Dubins paths. The second technique constructs local multi-resolution maps using an occupancy grid, which give higher resolution to the areas that are close to MAVs and give lower resolution to the areas that are far away. The maps are built using a log-polar representation. The two planning techniques are demonstrated in simulation and flight tests. Based on the observation that a camera does not provide accurate time-to-collision (TTC) measurements, two and three dimensional observability-based planning algorithms are explored. The techniques estimate both TTC and bearing using bearing-only measurements. A nonlinear observability analysis of state estimation process is conducted to obtain the conditions for complete observability of the system. Using the conditions, the observability-based planning algorithms are designed to minimize the estimation uncertainties while simultaneously avoiding collisions. The two dimensional planning algorithm parameterizes an obstacle using TTC and azimuth, and constructs local polar maps. The three dimensional planning algorithm parameterizes an obstacle using inverse TTC, azimuth, and elevation, and constructs local spherical maps. The algorithms are demonstrated in simulation. Lastly, a probabilistic path planning algorithm is developed for tracking a moving target in urban environments using UAVs and UGVs. The algorithm takes into account occlusions due to obstacles. It models the target using a dynamic occupancy grid and updates the target location using a Bayesian filter. Based on the target's current and probable future locations, a decentralized path planning algorithm is designed to generate suboptimal paths that maximize the sum of the joint probability of detection for all vehicles over a finite look-ahead horizon. Results demonstrate the planning algorithm is successful in solving the moving target tracking problem in urban environments.

Unmanned aircraft systems (UAS) represent the future of modern aviation. Over the past 10 years their use abroad by the military has become commonplace for surveillance and combat. Unfortunately, their use at home has been far more restrictive. Due to safety and regulatory concerns, UAS are prohibited from flying in the National Airspace System without special authorization from the FAA. One main reason for this is the lack of an on-board pilot to "see and avoid" other air traffic and thereby maintain the safety of the skies. Development of a comparable capability, known as "Sense and Avoid" (SAA), has therefore become a major area of focus. This research focuses on the SAA problem as it applies specifically to small UAS. Given the size, weight, and power constraints on these aircraft, current approaches fail to provide a viable option. To aid in the development of a SAA system for small UAS, various simulation and hardware tools are discussed. The modifications to the MAGICC Lab's simulation environment to provide support for multiple agents is outlined. The use of C-MEX s-Functions to improve simulation performance and code portability is also presented. For hardware tests, two RC airframes were constructed and retrofitted with autopilots to allow autonomous flight. The development of a program to interface with the ground control software and run the collision avoidance algorithms is discussed as well. Intruder sensing is accomplished using a low-power, low-resolution radar for detection and an Extended Kalman Filter (EKF) for tracking. The radar provides good measurements for range and closing speed, but bearing measurements are poor due to the low-resolution. A novel method for improving the bearing approximation using the raw radar returns is developed and tested. A four-state EKF used to track the intruder's position and trajectory is derived and used to provide estimates to the collision avoidance planner. Simulation results and results from flight tests using a simulated radar are both presented. To effectively plan collision avoidance paths a tree-branching path planner is developed. Techniques for predicting the intruder position and creating safe, collision-free paths using the estimates provided by the EKF are presented. A method for calculating the cost of flying each path is developed to allow the selection of the best candidate path. As multiple duplicate paths can be created using the branching planner, a strategy to remove these paths and greatly increase computation speed is discussed. Both simulation and hardware results are presented for validation.

Today a group of automated guided vehicles at Toyota Material Handling Manufacturing Sweden detect and avoid objects primarily by using 2D-LiDAR, with shortcomings being the limitation of only scanning the area in a 2D plane and missing objects close to the ground. Several dynamic obstacles exist in the environment of the vehicles. Protruding forks are one such obstacle, impossible to detect and avoid with the current choice of sensor and its placement. This thesis investigates possible solutions and limitations of using a single RGB camera for obstacle detection, tracking, and avoidance. The obstacle detection uses the deep learning model YOLOv5s. A solution for semi-automatic data gathering and labeling is designed, and pre-trained weights are chosen to minimize the amount of labeled data needed. Two different approaches are implemented for the tracking of the object. The YOLOv5s detection is the foundation of the first, where 2D-bounding boxes are used as measurements in an Extended Kalman Filter (EKF). Fiducial markers build up the second approach, used as measurements in another EKF. A state lattice motion planner is designed to find a feasible path around the detected obstacle. The chosen graph search algorithm is ARA*, designed to initially find a suboptimal path and improve it if time allows.  The detection works successfully with an average precision of 0.714. The filter using 2D-bounding boxes can not differentiate between a clockwise and counterclockwise rotation, but the performance is improved when a measurement of rotation is included. Using ARA* in the motion planner, the solution sufficiently avoids the obstacles.

During ice voyages, level ice and iceberg with huge inertia force can cause large deformation and even damage on the ship hull structure. Hence the hull structure for ice voyage requires higher strength than it for open water voyages. A container ship will be re-designed for ice voyages in the thesis. Generally, the ice strength is evaluated in ice class rules. IACS polar class and FSICR are adopted in this thesis. Ice class rules are based on experience and experiment data, but there has been no exact formula or parameters to described the ice properties so far. In other words, the results from ice class rules include uncertainties. In order to improve physical understanding, non-linear FE simulations will be processed after the re-design. In the simulations, the ship has a collision with different ice scenarios. The simulations are carried on ANSYS Workbench Explicit Dynamic using the solver of Auto-dyna. Afterwards, the results from the two designs schemes are compared and analysed.

Prescription drug use is a growing public health concern and studies show it is a contributing risk to motor vehicle collisions. The Appalachian region is also known to have an ever-increasing number of patients on controlled substances. This retrospective study of patients from the years 2011-2015 on controlled substances presenting to an Appalachian Level 1 trauma center after a motor vehicle or motorcycle collision was analyzed in order to determine the rate of opioid use among victims of motor vehicle collisions in the system, as well as evaluate for any differences in resource utilization between these patients and patients not using controlled substances. A total of 2,570 patients were included in the study. Seven-hundred sixty-eight (29.9%) individuals were found to be on a controlled substance. There was a similar mortality rate in both groups (2.8% vs 3.6%). There was no significant difference in hospital length of stay (LOS), intensive care unit (ICU) LOS, ventilator days, or injury severity score. Statistically significant findings include the type of crash (motor vehicle crash vs motorcycle crash) (p=0.003) and position in the vehicle (driver vs passenger) (p<0.001). Motor vehicle crashes and driver position were significantly associated with the presence of a controlled substance.

On April 21, 2001, the United States and China faced their first major incident of the 21st century when a U.S. spy plane accidentally collided with a Chinese fighter plane. The dialogue that followed between the two countries, as well as the tenor of the incident as reported in the international press, provide some interesting and insightful glimpses into how these major powers handled the incident in the days and weeks that followed. Although the mainstream media in both China and the United States reported the key facts and elements of the incident in a similar fashion, the spin that was ultimately placed on the event by the Chinese press was clearly indicative of the Asian state's desire to portray the United States as being at fault; however, because both countries have an enormous stake in ensuring continued friendly relations for trade purposes, the Chinese press eventually adopted an official position that would allow the United States to "save face" while ensuring that the killed Chinese pilot involved was lauded as a fearless hero of the state and a martyr to its cause. To determine how these events played out in the respective mainstream media of China and the United States, as well as the international media, this research provides a review of the relevant literature to identify how the spy plane collision was portrayed, what elements are regarded as important for analysis. This study compares the two accounts from China and the U.S., and to a lesser extent, the international media, by grouping the media accounts into three separate dimensions: 1) visual framing, 2) contextual framing and 3) operational framing, to determine how these factors played out in the spy plane incident. The analysis of the media accounts is followed by a summary of the research in the concluding paragraph.

In order to follow increasingly strict regulation of pollutant emissions, a new concept of Lean Premixed pre-vaporized (LPP) combustion has been proposed for turbines. In LPP combustion, controlled atomization, dispersion and vaporization of different types of liquid fuel in the premixer are the key factors required to stabilize the combustion process and improve the efficiency. A numerical study is conducted for the fundamental understanding of the liquid fuel dispersion and vaporization process in pre-mixers using both cross-flow and co-flow injection methods. First, the vaporization model is validated by comparing the numerical data to existing experiments of single droplet vaporization under both low and high convective air temperatures. Next, the dispersion and vaporization process for biofuels and conventional fuels injected transversely into a typical simplified version of rectangular pre-mixer are simulated and results are analyzed with respect to vaporization performance, degree of mixedness and homogeneity. Finally, collision model has been incorporated to predict more realistic vaporization performance. Four fuels, Ethanol, Rapeseed Methyl Esters (RME), gasoline and jet-A have been investigated. For mono-disperse spray with no collision model, the droplet diameter reduction and surface temperature rise were found to be strongly dependent on the fuel properties. The diameter histogram near the pre-mixer exit showed a wide droplet diameter distribution for all the fuels. In general, pre-heating of the fuels before injection improved the vaporization performance. An improvement in the drag model with Stefan flow correction showed that a low speed injection and high cone angle improved performance. All fuels achieved complete vaporization under a iv spray cone angle of 140°. In general, it was found that cross-flow injection achieved better vaporization performance than co-flow injection. A correlation is derived for jet-A‟s total vaporization performance as a function of non-dimensional inlet air temperature and fuel/air momentum flux ratio. This is achieved by curve-fitting the simulated results for a broad range of inlet air temperatures and fuel/air momentum flux ratios. The collision model, based on no-time-counter method (NTC) proposed by Schmidt and Rutland, was implemented to replace O‟Rourke‟s collision algorithm to improve the results such that the unphysical numerical artifact in a Cartesian grid was removed and the results were found to be grid-independent. The dispersion and vaporization processes for liquid fuel sprays were simulated in a cylindrical pre-mixer using co-flow injection method. Results for jet-A and Rapeseed Methyl Esters (RME) showed acceptable grid independence. At relatively low spray cone angle and injection velocity, it was found that the collision effect on the average droplet size and the vaporization performance were very high due to relatively high coalescence rate induced by droplet collisions. It was also found that the vaporization performance and the level of homogeneity of fuel-air mixture could be significantly improved when the dispersion level is high, which can be achieved by increasing the spray cone angle and injection velocity. In order to compare the performance between co-flow and cross-flow injection methods, the fuels were injected at an angle of 40° with respect to the stream wise direction to avoid impacting on the wall. The cross-flow injection achieved similar vaporization performance as co-flow because a higher coalescence rate induced by droplet collisions cancelled off its higher heat transfer efficiency between two phases for cross-flow injections.

In this dissertation, a novel and generic solution of trajectory generation is developed and evaluated for ground and aerial vehicles in a dynamic environment. By explicitly considering a kinematic model of the ground vehicles, the family of feasible trajectories and their corresponding steering controls are derived in a closed form and are expressed in terms of one adjustable parameter for the purpose of collision avoidance. A collision-avoidance condition is developed for the dynamically changing environment, which consists of a time criterion and a geometrical criterion. By imposing this condition, one can determine a family of collision-free paths in a closed form. Then, optimization problems with respect to different performance indices are setup to obtain optimal solutions from the feasible trajectories. Among these solutions, one with respect to the near-shortest distance and another with respect to the near-minimal control energy are analytical and simple. These properties make them good choices for real-time trajectory planning. Such optimal paths meet all boundary conditions, are twice differentiable, and can be updated in real time once a change in the environment is detected. Then this novel method is extended to 3D space to find a real-time optimal path for aerial vehicles. After that, to reflect the real applications, obstacles are classified to two types: "hard" obstacles that must be avoided, and "soft" obstacles that can be run over/through. Moreover, without losing generality, avoidance criteria are extended to obstacles with any geometric shapes. This dissertation also points out that the emphases of the future work are to consider other constraints such as the bounded velocity and so on. The proposed method is illustrated by computer simulations.