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Lenslet Array and Fabry-Perot Based Hyperspectral Imaging
No full textWe present a novel technique of imaging a 2D region such that the image formed has both spectral and spatial information in a single frame. This technique uses a combination of a microlenslet array and a Fabry-Perot etalon to generate multiple images of the region at different wavelength positions. This results in the formation of a hyperspectral image in a single snapshot. The instrument contains no moving parts and uses the property of blueshift of the transmitted wavelength as the angle of incidence increases on an etalon. The spectral band covered, field of view of the region, and the hyperspectral bands needed can be selected and altered by a simple change in the combination of focal length of imaging and collimating lenses used in the setup. Results obtained from solar observation of two regions in absorption and emission lines, respectively, are presented. A conceptual design of extending the capability of this instrument to perform hyperspectropolarimetry is also presented
Evaporation-Oscillation Driven Assembly: Microtailoring the Spatial Ordering of Particles in Sessile Droplets
No full textThis work explores the physical mechanism that can be used to control the final residual pattern of nanoparticles obtained from an evaporating-oscillating sessile droplet. To that end, the substrate is vibrated in the vertical direction with a constant amplitude, while the frequency of excitation is varied. It is found that evaporation progressively shifts the mode number of the oscillating droplet to lower values, while the oscillations enhance the rate of solvent loss, causing a reduction in the droplet lifetime. The coupling between evaporation and oscillation drives the internal flow through two distinct regimes. Initially, oscillation leads to inner flow recirculation, which delays the evaporation driven edge deposition of particles. Subsequently at lower modes, caused by solvent depletion, the effect of oscillation is weakened, which allows evaporation-driven flow to gain prominence and thus transport the dispersed particles to the contact line. We demonstrate here how this delay in particle migration can be controlled to engineer morphological changes in not just the resulting macroscopic aspect of the deposit but also its microstructure. We especially focus on the relatively unexplored microstructural pattern of deposits from evaporating-oscillating droplets. Using scanning electron micrograph and Voronoi tessellation of the final deposit, we show unique spatial variation in particle ordering at macro-micro length scales. Thus, droplet oscillation tunes the spatial extent of the particle ordering crucial in applications like photonic crystals and photonic glass
Form-closure of planar mechanisms: Synthesis of number, configuration, and geometry of point contacts
No full textThis paper presents a study on restraining the motion of planar mechanisms using point contacts between the links of the mechanisms. First-order form-closure (FFC) and second-order form-closure (SFC) of 1- and 2-degrees-of-freedom (d.o.f.) smooth planar motions are studied. It is shown geometrically that two and three point contacts are sufficient for FFC of an object which is capable of executing 1- and 2-d.o.f. motions respectively. These results are applied for FFC of planar mechanisms. A theory for contact curvature based SFC of 1- and 2-d.o.f. motions with a single point contact is presented. It is derived that the instantaneous point-path curvature of points on a specific line of a 2-d.o.f. moving plane is always bounded. Using this result, a procedure is chalked out for immobilizing land 2-d.o.f. mechanisms with a single contact. Illustrations of immobilizing four-bar and 2R-mechanisms are presented. Rapid prototyped model of the four-bar mechanism and stoppers is fabricated and the SFC theory is verified. (C) 2018 Elsevier Ltd. All rights reserved
Human Crawl vs Animal Movement and Person with Object Classifications Using CNN for Side-view Images from Camera
No full textAn optical camera-based intrusion classification system (Light Intrusion DeTection systEm named as acronym LITE) for an outdoor setting was recently developed by a superset of the authors. The system classified between human and animal images captured in a side-view manner based on the height. Based on the system and algorithm design, most probably human-crawl would be classified as animal by the LITE. In this paper, classification between human-crawl and animal is addressed. In addition to this work, classification of person with weapon versus person with vehicle is also addressed (referred as person with object) to provide more information about the type of intrusions. A Convolutional Neural Network (CNN) based approach is used to solve the above stated two problems. In the case of `` person with object'' classification, a study of different CNN architectures was carried out and analysis corresponding to that is presented. In case of human crawl vs animal movement, performance results corresponding to only the best architecture model is provided among the many tried models. Further on, additional insights are provided about the classification using the attention heat maps and t-SNE plots. The test classification accuracies for human-crawl vs animal and person with object classification on the recorded data are close to 95:65% and 90%, respectively. The LITE, having the Odroid C2 (OC2) Single-Board Computer (SBC) with CNN-based classification algorithm for human-crawl versus animal task ported on it, was deployed in an outdoor setting for a realtime deployment. It provided a classification accuracy close to 92%
Extracting and Visualising Character Associations in Literary Fiction using Association Rule Learning
No full textIn many works of fiction, the complexity and evolution of associations between characters is an important aspect of the narrative. Associations between characters are traditionally modeled as undirected networks where vertices are characters in the story and each edge {a, b} represents a pair of associated characters a and b, possibly with the strength of the association represented as an edge weight. In this paper, we present a novel application of association rule learning to determine a richer class of character associations in fictional works between (non-empty, non-overlapping) sets of characters A and B in an almost completely automated way. Furthermore, associations are directed (associations A double right arrow B and B double right arrow A may differ in strength), and we demonstrate that standard metrics (support, confidence and lift) can be used to determine association strength in the context of literary analysis. Association rules can be expressed as Character Association Networks (CANs), and we demonstrate that visualising the evolution of these networks and computing centrality measures for such networks can rapidly provide literary analysts with insights such as identifying protagonists and key clusters of characters
ATP-dependent membrane remodeling links EHD1 functions to endocytic recycling
No full textEndocytic and recycling pathways generate cargo-laden transport carriers by membrane fission. Classical dynamins, which generate transport carriers during endocytosis, constrict and cause fission of membrane tubes in response to GTP hydrolysis. Relatively, less is known about the ATP-binding Eps15-homology domain-containing proteinl (EHD1), a dynamin family member that functions at the endocytic-recycling compartment. Here, we show using cross complementation assays in C. elegans that EHD1's membrane binding and ATP hydrolysis activities are necessary for endocytic recycling. Further, we show that ATP-bound EHD1 forms membrane-active scaffolds that bulge tubular model membranes. ATP hydrolysis promotes scaffold self-assembly, causing the bulge to extend and thin down intermediate regions on the tube. On tubes below 25 nm in radius, such thinning leads to scission. Molecular dynamics simulations corroborate this scission pathway. Deletion of N-terminal residues causes defects in stable scaffolding, scission and endocytic recycling. Thus, ATP hydrolysis-dependent membrane remodeling links EHD1 functions to endocytic recycling
B-B Coupling and B-B Catenation: Computational Study of the Structure and Reactions of Metal-Bis(borylene) Complexes
No full textA detailed molecular orbital analysis of the metal-bis(borylene) complex Fe(CO)(3){B(Dur)B(N(SiMe3)(2))}] (Dur=2,3,5,6-tetramethylphenyl) (1 a) serves as a focal point of recent developments in this area of chemistry, such as B-B coupling and B-B catenation reactions. There is strong a pi delocalization between the Fe(CO)(3) and (B-Dur)(B-N(SiMe3)(2)) units; the short B-B distance in 1 a is due to this pi delocalization. The pi-donor ligand N(SiMe3)(2) on the boron provides a decisive stability to the complex 1 a. The LUMO of 1 a has B-B sigma-bonding character. Hence B-B coupling is facilitated by filling the LUMO. Strong sigma-donating ligands, such as PMe3 or PCy3, induce B-B coupling. Expulsion of one CO from 1 a followed by dimerization leads to Fe(CO)(2){B(Dur)B(N(SiMe3)(2))}](2) (3 a) with a short Fe-Fe distance of 2.355 angstrom. A detailed mechanism for the reaction of 3 a with CO to give the B-B catenation product 2 f is presented. The bonding of all intermediates is compared to their isolobal main-group analogues
DivGroup: A Diversified Approach to Divide Collection of Patterns into Uniform Groups
No full textSimilarity based grouping of patterns has been explored profusely under the well celebrated clustering paradigm in pattern recognition and machine learning. In clustering, objects in the same cluster are similar to each other and objects belonging to different clusters are dissimilar in a corresponding sense. However, it is not rare to come across situations where instead of a similarity based grouping, forming groups of diverse objects is needed. Resource allocation across different parts of an organization, performing cross-validation splits of dataset with class imbalance, heterogeneous or mixed ability partitioning of students, etc. are the applications of grouping which require each group to contain diverse set of patterns. Moreover, these applications also demand different groups to be similar to each other in some sense. In this work, we propose a generic framework for partitioning a collection of patterns into a set of groups such that the above two criteria are fulfilled. To the best of our knowledge, this is the first work to propose such a framework irrespective of any particular application. Towards this end, it turns out that finding an optimal solution to the problem that we developed is NP Hard. So we propose an approximate solution for the same. We conduct experiments on both synthetic and real world datasets to evaluate the performance of the proposed algorithm. We show the merit of the algorithm by comparing the results with some related state-of-the-art baseline methods
A Novel Least Component Count Single DC-link Fed Generalized Multilevel Inverter Configuration for Three-phase High Power Isolated Grid Connected Systems
No full textThis paper presents a novel generalized multilevel inverter topology using a single DC link and with the least component count for high power isolated grid integration of renewable energy sources such as solar photovoltaic (PV). The topology is able to generate various voltage levels starting from 3 to `N' levels. The proposed inverter topology consists of two stages such as two-phase inverter and the Scott-T transformer. Former stage converts the DC voltage into two-phase system of electrical quantities, while the later stage converts two-phase quantities into the three phase quantities by using a Scott-T transformer. The proposed topology results in the usage of reduced active power devices and corresponding gate drives, power diodes, flying and DC-link capacitors. Main advantage of this configuration is that the topology employs only a single DC-link, and the DC-link capacitors have an inherent ability to self balance their voltages without the need of extra capacitor voltage balancing algorithms or circuits. A simple and conventionally available level shifted carrier based pulse width modulation strategy is employed for controlling the power devices. The inverter is operated in the current control mode to inject power into the grid at unity power factor. Circuit analysis along with the simulation results for a nine level grid connected operation with a lab scale power level of 1 kW is discussed in this paper
Six new Cyrtodactylus (Squamata: Gekkonidae) from northeast India
No full textWe use mitochondrial sequence data to identify divergent lineages within the gekkonid genus Cyrtodactylus in northeast India and use morphological data to describe six new species from within the Indo-Burma Glade of Cyrtodactylus. The new species share an irregular colour pattern but differ from described species from the region in morphology and mitochondrial sequence data (>11 % uncorrected pairwise sequence divergence). Three new species are from along the Brahmaputra River and three are from mountains south of the Brahmaputra, including the largest Cyrtodactylus from India and the fifth gecko to be described from a major Indian city, Guwahati