Ground Extraction from 3D Lidar Point Clouds

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works Pomares, A., Martínez, J.L., Mandow, A., Martínez, M.A., Morán, M., Morales, J. Ground extraction from 3D lidar point clouds with the Classification Learner App (2018) 26th Mediterranean Conference on Control and Automation, Zadar, Croatia, June 2018, pp.400-405. DOI: PendingGround extraction from three-dimensional (3D) range data is a relevant problem for outdoor navigation of unmanned ground vehicles. Even if this problem has received attention with specific heuristics and segmentation approaches, identification of ground and non-ground points can benefit from state-of-the-art classification methods, such as those included in the Matlab Classification Learner App. This paper proposes a comparative study of the machine learning methods included in this tool in terms of training times as well as in their predictive performance. With this purpose, we have combined three suitable features for ground detection, which has been applied to an urban dataset with several labeled 3D point clouds. Most of the analyzed techniques achieve good classification results, but only a few offer low training and prediction times.This work was partially supported by the Spanish project DPI 2015- 65186-R. The publication has received support from Universidad de Málaga, Campus de Excelencia Andalucía Tech

Parameters that determine the wavelength of a passive mode-locked dye laser

We introduce a new stability criterion that should be added to previous theoretical models of passive mode locked lasers in order to predict emission wavelength, which is to require that the pulse spectrum reproduces itself after one transit. The CPM laser consisting of rhodamine 6G as gain medium and DODCI as saturable absorber is studied. The relative population balance of the fundamental and photoisoner species of the DODCI are computed as a function of the pulse energy and wavelength. The necessity of a spectral stability criterion follows from the dependence of the gain profile on the pulse parameters. Use of the criterion is shown to agree with previous experimental results, such as the red spectral region of emission and dependence of emission wavelength on absorber concentration. This criterion is expected to be an useful tool in order to select other dye combinations and predict the laser behavior. Parameters that determine the wavelength of a passive mode-locked dye laser

DOPE–oleic acid–Ca2+ as DNA condensing agent

Phospholipid-based non-viral carriers composed of neutral phospholipid dioleoylphosphatidylethanolamine (DOPE) and the binary mixture DOPE-oleic acid (OA) are examined as potential DNA delivery vectors. The process of DNA condensation in the presence of Ca2+ions has been monitored through changes in emmision intensity of fluorescent probe ethidium bromide. The decline in fluorescence intensity with increasing Ca2+concentration at two different time intervals was correlated with the binding capacity of complexes and possible release of DNA from the complex. The microstructure of DOPE-OA mixtures at different OA/DOPE molar ratios and that of DOPE-OA-DNA-Ca2+complexes were determined using synchrotron small angle X-ray diffraction (SAXD). We identified inverted hexagonal phase HIIas the dominant structure. OA affects the lattice parameter of HIIformed by DOPE. With the increasing OA/DOPE molar ratio, the lattice parameter decreases, which results in significantly lower fraction of DNA bound to the OA-enriched complexes

Wireless sensor network for forest fire detection

Some methods for fire detection include monitoring from watch towers and the use of satellite images [1] [2]. Unfortunately, these are not efficient due to several reasons, such as high infrastructure costs (sophisticated equipment), the fact that they require a large number of trained personnel and that they make real-time monitoring difficult, since when the phenomenon is detected, its speed of propagation has produced uncontrollable levels of damage. This paper proposes a method for detecting forest fires, using a network of wireless sensors and information fusion methods

Soft-x-ray interferometer for single-shot laser linewidth measurements

Includes bibliographical references (page 957).A soft-x-ray Mach-Zehnder interferometer configuration that makes use of the time delay introduced by diffraction gratings to conduct single-shot measurements of the linewidth of soft-x-ray laser amplifiers is proposed and analyzed. The scheme was experimentally demonstrated in the near-IR region of the spectrum by measurement of the mode separation of a semiconductor laser. A symmetric configuration with compensated time delays that can be implemented for plasma diagnostics and for evaluating soft-x-ray optics is also discussed

Microsaccade generation requires a foveal anchor

Visual scene characteristics have the ability to affect various aspects of saccade and microsaccade dynamics. For example, blank visual scenes are known to elicit diminished saccade and microsaccade production, compared to natural scenes. Similarly, microsaccades are less frequent in the dark. Yet, the extent to which foveal and peripheral visual information contribute to microsaccade production remains unclear: because microsaccade are directed to covert attention locations as per the superior colliculus activation map, it follows that peripheral stimulation could suffice to produce regular microsaccade dynamics, even without foveal stimulation being present. Here we compared the characteristics of microsaccades generated in the presence or absence of foveal and/or peripheral visual stimulation, while human subjects conducted four types of oculomotor tasks (fixation, free-viewing, guided-viewing and fixation during passive viewing). Foveal information was either available, or made unavailable by the presentation of both solid and blurred scotomas. We found foveal stimulation to be critical for microsaccade production, and peripheral stimulation, by itself, to be insufficient to yield microsaccades. Our results indicate that a foveal visual anchor is necessary for microsaccade generation.  

The effects of fixation target size and luminance on microsaccades and square-wave jerks

A large amount of classic and contemporary vision studies require subjects to fixate a target. Target fixation serves as a normalizing factor across studies, promoting the field’s ability to compare and contrast experiments. Yet, fixation target parameters, including luminance, contrast, size, shape and color, vary across studies, potentially affecting the interpretation of results. Previous research on the effects of fixation target size and luminance on the control of fixation position rendered conflicting results, and no study has examined the effects of fixation target characteristics on square-wave jerks, the most common type of saccadic intrusion. Here we set out to determine the effects of fixation target size and luminance on the characteristics of microsaccades and square-wave jerks, over a large range of stimulus parameters. Human subjects fixated a circular target with varying luminance and size while we recorded their eye movements with an infrared video tracker (EyeLink 1000, SR Research). We detected microsaccades and SWJs automatically with objective algorithms developed previously. Microsaccade rates decreased linearly and microsaccade magnitudes increased linearly with target size. The percent of microsaccades forming part of SWJs decreased, and the time from the end of the initial SWJ saccade to the beginning of the second SWJ saccade (SWJ inter-saccadic interval; ISI) increased with target size. The microsaccadic preference for horizontal direction also decreased moderately with target size . Target luminance did not affect significantly microsaccades or SWJs, however. In the absence of a fixation target, microsaccades became scarcer and larger, while SWJ prevalence decreased and SWJ ISIs increased. Thus, the choice of fixation target can affect experimental outcomes, especially in human factors and in visual and oculomotor studies. These results have implications for previous and future research conducted under fixation conditions, and should encourage forthcoming studies to report the size of fixation targets to aid the interpretation and replication of their results

The biodiversity of freshwater Crustaceans revealed by taxonomy and mitochondrial DNA barcodes

Cytochrome oxidase subunit I (COI) barcode sequences in this file were obtained from specimens collected by plankton net in western Lake Erie in 2012 & 2013, along with later specimens collected at various locations and times, including some collected in Belize in 2015. Methods and other details about these sequences are described in a paper by the same authors in a submitted publication (2021: URL to be given here when published). The right columns below contain additional notes on lengths of sequences, GenBank accession ID (when obtained), and annotation as to whether the sequence represents a new barcode for its genus or species taxon. According to our experience, a DNA identity of \u3e96.5% with previous GenBank barcodes is a reliable range for determining a species level barcode for that morpho species; a DNA identity of 90.5% to 96.5% with previous barcodes is sufficient to identify genus. DNA identities within these ranges are considered to be barcode confirmations. Conversely, DNA identities outside of these ranges are considered to be new barcodes for that species or genus, respectively. Contradictions with previous GenBank sequences are discussed in the manuscript. The submitted manuscript includes the highest percentage identity to a previous sequence in GenBank as determined by BLASTN in June2021. The FASTA file name given here begins with a Ram Lab ID number-location and date of collection with format varying somewhat between various collections/collectors but generally including several (usually three) location letters (e.g., BHL stands for Blue Heron Lagoon) and the date usually in a 6-character format of MMDDYY, and optionally a sample number for that date either preceding the location letters or following the date. Collection location abbreviations include the following: All sequences starting with PM, Toledo Harbor in western Lake Erie; LMUSK, Lake Muskoday, Belle Isle, Detroit; SCL, Saint Clair River; BHL, Blue Heron Lagoon, Belle Isle; LE, LakeErie; LSC, Lake St.Clair; MMLE; Metzgers Marsh, LakeErie; MM, Metzgers Marsh; LP, Leonard Preserve, Manchester, Michigan; HR, Huron River Drive, Ypsilanti, Michigan; LCL, Little Cedar Lake, Orion, MI; HLE, Harbor Lake Erie; LHLE, Lorain Harbor Lake Erie; BZEB1P, Cenote in Shipstern Reserve, Corozal, Belize, Central America

Serendipitous discovery of RR Lyrae stars in the Leo V ultra-faint galaxy

During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 +/- 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RR Lyrae stars. This serendipitous discovery shows that distant RR Lyrae stars may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.Comment: Accepted in ApJ Letter