Localization of visually indistinguishable mature lettuce heads using spatial information

This paper describes an approach to recognizing and localizing centers of mature lettuce heads in the field when the lettuce leaves obscure the distinctions between plants. This is of great value when using an automatic harvester in cluttered or closely planted vegetation. The aim of this work is to investigate and verify the potential use of spatial rather than visual clues for recognition and localization, with a view to implementing a more robust and sophisticated system if promise is shown. Colour/texture information was difficult to use so spatial information was used instead. A laser range finder was used to generate a height plot from above the plants. Lettuce examples were used to learn the radial distribution of the lettuce model. This was compared with the distributions of arbitrary locations in new scans to locate possible lettuce locations. Planting distance information was then used to localize the final lettuce positions. The algorithm was able to successfully locate 15 out of 16 sample lettuces

Classification of Bidens in wheat farms

Bidens pilosa L (commonly known as cobbler's peg) is an annual broad leaf weed widely distributed in tropical and subtropical regions of the world and is reported to be a weed of 31 crops including wheat. Automatic detection of Bidens in wheat farms is a nontrivial problem due to their similarity in color and presence of occlusions. This paper proposes a methodology which could be used to discriminate Bidens from wheat to be used in operations such as autonomous weed destruction. A spectrometer is used to analyze the optical properties of Bidens and wheat leaves while achieving high classification results. However, due to the practical constraints of using spectrometers, a color camera based technique is proposed. It is shown that the color based segmentation followed by shape based validation algorithm gives rise to high detection rates with lower false detections. We have experimentally evaluated the algorithm with Bidens detection rate of 80% and a 10% false alarm rate

Streptococcus agalactiae glyceraldehyde-3-phosphate dehydrogenase (GAPDH) elicits multiple cytokines from human cells and has a minor effect on bacterial persistence in the murine female reproductive tract

Streptococcus agalactiae glyceraldehyde 3-phosphate dehydrogenase (GAPDH), encoded by gapC, is a glycolytic enzyme that is associated with virulence and immune-mediated protection. However, the role of GAPDH in cellular cytokine responses to S. agalactiae, bacterial phagocytosis and colonization of the female reproductive tract, a central host niche, is unknown. We expressed and studied purified recombinant GAPDH (rGAPDH) of S. agalactiae in cytokine elicitation assays with human monocyte-derived macrophage, epithelial cell, and polymorphonuclear leukocyte (PMN) co-culture infection models. We also generated a S. agalactiae mutant that over-expresses GAPDH (oeGAPDH) from gapC using a constitutively active promoter, and analyzed the mutant in murine macrophage antibiotic protection assays and in virulence assays in vivo, using a colonization model that is based on experimental infection of the reproductive tract in female mice. Human cell co-cultures produced interleukin (IL)-1β, IL-6, macrophage inflammatory protein (MIP)-1, tumor necrosis factor (TNF)-α and IL-10 within 24 h of exposure to rGAPDH. PMNs were required for several of these cytokine responses. However, over-expression of GAPDH in S. agalactiae did not significantly affect measures of phagocytic uptake compared to an empty vector control. In contrast, oeGAPDH-S. agalactiae showed a small but statistically significant attenuation for persistence in the reproductive tract of female mice during the chronic phase of infection (10–28 days post-inoculation), relative to the vector control. We conclude that S. agalactiae GAPDH elicits production of multiple cytokines from human cells, and over-expression of GAPDH renders the bacterium more susceptible to host clearance in the female reproductive tract. One-sentence summary: This study shows Streptococcus agalactiae glyceraldehyde 3-phosphate dehydrogenase, an enzyme that functions in glycolysis, gluconeogenesis and virulence, modifies phagocytosis outcomes, including cytokine synthesis, and affects bacterial persistence in the female reproductive tract

Integration of sliding mode based steering control and PSO based drive force control for a 4WS4WD vehicle

© 2017, Springer Science+Business Media, LLC. The aim of this paper is to present a novel approach to enable a four-wheel steer four-wheel drive (4WS4WD) vehicle to follow a predefined path under force control. The novelty is in the combination of a sliding mode controller that determines the steering angles using a kinematic model and a real-time particle swarm optimization based controller that determines the drive torques using a dynamic model. The dynamic model takes into account all the slip forces acting on the vehicle. The combined controllers are then used to drive the 4WS4WD vehicle to follow a path. In order to enable the implementation of the controllers, the path to be followed is generated using 7-order Bézier curves that can provide smooth kinematic and dynamic reference profiles. Simulation results are provided to demonstrate the applicability of the proposed methodology and its robustness

Relevant opportunistic information extraction and scheduling in heterogeneous sensor networks

4 page(s

Sensor relevance validation for autonomous mobile robot navigation

6 page(s