Path Planning for Bulldozers with Curvature Constraints

There is presently no solution to the problem of an autonomous bulldozer pushing mounds of material to desired goal locations in the presence of obstacles whilst obeying the kinematic constraints of the bulldozer. Past work has solved some aspects of this problem, but not all. This research presents the first complete, practical solution to the problem. It works by creating a fixed RRT in advance, and then during operation connecting pushing poses into this RRT using Bezier curves. The RRT algorithm leverages a novel data structure for performing nearest neighbour comparisons for Ackermann-steering vehicles; termed the Distmetree. The resulting pushing states are searched using greedy heuristic search to find a solution and the final path is smoothed with cubic Bezier curves. The mode of operation chosen for best performance also constructs bidirectional RRTs to reach difficult to access pushing poses. The final mode of the algorithm was tested in simulation and proven to be able to solve a wide variety of maps in a few minutes while obeying bulldozer kinematic constraints. The algorithm, whilst not optimal, is complete which is the more desirable property in industry, and the solutions it produces are both feasible and reasonable.

Path Planning for Bulldozers with Curvature Constraints

There is presently no solution to the problem of an autonomous bulldozer pushing mounds of material to desired goal locations in the presence of obstacles whilst obeying the kinematic constraints of the bulldozer. Past work has solved some aspects of this problem, but not all. This research presents the first complete, practical solution to the problem. It works by creating a fixed RRT in advance, and then during operation connecting pushing poses into this RRT using Bezier curves. The RRT algorithm leverages a novel data structure for performing nearest neighbour comparisons for Ackermann-steering vehicles; termed the Distmetree. The resulting pushing states are searched using greedy heuristic search to find a solution and the final path is smoothed with cubic Bezier curves. The mode of operation chosen for best performance also constructs bidirectional RRTs to reach difficult to access pushing poses. The final mode of the algorithm was tested in simulation and proven to be able to solve a wide variety of maps in a few minutes while obeying bulldozer kinematic constraints. The algorithm, whilst not optimal, is complete which is the more desirable property in industry, and the solutions it produces are both feasible and reasonable.

Creativity in Humans, Robots, Humbots

This paper examines three ways that robots can interface with creativity. In particular, social robots which are designed to interact with humans are examined. In the first mode, human creativity can be supported by social robots. In a second mode, social robots can be creative agents and humans serve to support robot's productions. In the third and final mode, there is complementary action in creative work, which may be collaborative co-creation or a division of labor in creative projects. Illustrative examples are provided and key issues for further discussion are raised.

Appreciation Modes in Empirical Aesthetics

There are three main modes of appreciation of aesthetic objects. The first is the appreciation of aesthetic pleasure, most often beauty. A simple account of the experience of beauty is the fluency theory of aesthetic pleasure. A more complex account assumes that there are two levels of aesthetic pleasure, a shallow one based on low-level experiences like fluency, and a deep level where disfluency leads to interest. The second mode of appreciation pertains to emotions experienced in response to an artwork, as illustrated by the distancing–embracing model of aesthetic emotions. The final mode of appreciation includes understanding an artwork. Cognitive models of artistic understanding assume that processes of perception, memory, and interpretation determine cognitive mastery. From the humanities tradition, cognitive models have been criticized because they neglect the historical context of the creation of the artwork as an objective component to understanding. A recent model combines art-historical context with cognitive processes and claims that such artistic understanding is essential to aesthetic appreciation.

Creativity in Humans, Robots, Humbots

This paper examines three ways that robots can interface with creativity. In particular, social robots which are designed to interact with humans are examined. In the first mode, human creativity can be supported by social robots. In a second mode, social robots can be creative agents and humans serve to support robot’s productions. In the third and final mode, there is complementary action in creative work, which may be collaborative co-creation or a division of labor in creative projects. Illustrative examples are provided and key issues for further discussion are raised.

Magnitude, Characteristics, Maternal and Feto-Neonatal Outcomes of Obstetric Emergencies in Western Ethiopia, Nekemte, Ethiopia

<p><strong>Objective</strong>: In Ethiopia very little or probably nothing is known about the significance of obstetric emergencies. This study was therefore aimed at assessing magnitude, characteristics, and outcomes of obstetric emergencies in western Ethiopia.</p><p><strong>Study Design:</strong> Institution based prospective cohort study was employed from January to June 2017. To select the hospitals, area sampling technique was used. Total of 567 pregnant women with obstetric emergencies presented and treated in respective hospitals during the study periods and met the inclusion criteria were consecutively included.</p><p><strong>Results:</strong> Majority (91.7%) of the identified obstetric emergencies have led to termination of pregnancy. Significant proportions of pregnant women (11%) who reached health facility died of obstetric emergencies. Pregnant women with obstetric emergencies traveled to facility carried by people were found to have died about 8 times more likely as compared to those who were transported by ambulance. While 29.21% of women gave birth to normal life births, stillbirth and neonatal death were 8.02% and 7.4% respectively. Higher number of neonatal death was also observed among mothers in whom final mode of delivery was a cesarean section (AOR: 0.19(0.05, 0.62)) compared to spontaneous vaginal delivery.</p><p><strong>Conclusion:</strong> This study has revealed that obstetric emergencies are responsible for the significant number of maternal and perinatal death. If the women have been accessed early and received optimum emergency care, many cases of the occurred death would have been prevented. Better outcome can be achieved through maximum utilization of quality and comprehensive antenatal care and organized pre-hospital obstetric emergency services.</p>

Crush Zone Morphology of Epoxy-Glass Fiber-Aluminium Composite Columnar Tube due to Longitudinal Crushing Force

Epoxy–glass fiber–aluminium composite may be of interest for energy absorption application due to their improved crashworthiness. In the current study, the hybrid–composite columnar tube specimen has been fabricated by a hand lay–up method using epoxy–glass fiber with aluminium columnar tube as a core material. An experimental quasi–static crush test has been performed on the specimen under axial loading. The post–crushing of composite lay–up configuration was observed during and after interaction of the axial loading with the specimen. The result of crush morphology analysis on final mode of failure of the specimen was carried out using SEM and showed combination of several failure modes such as matrix–fiber interfacial fracture, fiber breakage and hackles. However, the main failure mode is brittle type fracture comprising transverse shearing and splaying modes.