•Limitations of Dynamic Time Warping (DTW) highlighted for online signature verification problem.•The first work of its kind that analyzes the characteristics of the warping path, using Vector ...Quantization (VQ).•Proposal for enhancing the performance of DTW based online signature verification using VQ.•Proposal of inclusion of contextual information to the enhanced DTW strategy.•Efficacy of the methodology is tested on the well known SVC 2004 and MCYT 100 database.
This work presents an enhanced Dynamic Time Warping (DTW) based online signature verification system by utilizing the code-vectors generated from a Vector-Quantization (VQ) strategy. The DTW algorithms in the literature use only the distance score, obtained between the test signature and the genuine enrolled signatures, for the decision rule. The optimal warping path is constructed by placing constraints between the pairs of the sample points of the signatures, that are to be aligned. Hence, at times, sole dependence of the DTW scores may not be effective to discriminate the genuine and forgery signatures of an user, especially, when their values are very close. In order to alleviate this issue, we propose a novel scheme of scoring/voting the aligned pairs in the warping path by a set of code-vectors constructed from a VQ step. We subsequently fuse this score with that of the DTW, by popular score combination strategies, for verifying a test signature. As a second contribution, we consider the incorporation of contextual information in the formulation to reduce the equal error rate of the verification system. The experiments on the publicly available SVC 2004 and MCYT 100 databases confirm the efficacy of our proposal. To the best of our knowledge, this work is the first of its kind, that exploits the characteristics of the warping path for online signature verification.
This paper explores the utility of information derived from the dynamic time warping (DTW) cost matrix for the problem of online signature verification. The prior works in literature primarily ...utilize only the DTW scores to authenticate a test signature. To the best of our knowledge, the characteristics of the warping path (used for the alignment) in the cost matrix is hardly exploited for verification of online signatures. Accordingly, we devise a score that utilizes the information from the cost matrix and warping path alignments. We subsequently consider its fusion (using a sum rule combiner) with the DTW score for authenticating the veracity of a test signature. In addition, a minor modification is suggested with regards to the set of features employed for matching the signatures. We introduce a spacing parameter for feature extraction and demonstrate its applicability in increasing the separation between the distribution of genuine and forgery signatures for an user. Our method has been tested on two publicly available online signature databases namely the SVC-2004 Task 2 and MCYT-100. We report reduction in error rates over the traditional DTW framework.
The antifungal effects of four essential oils viz., clove (Syzygium aromaticum), lemongrass (Cymbopogon citratus), mint (Mentha × piperita) and eucalyptus (Eucalyptus globulus) were evaluated against ...wilt causing fungus, Fusarium oxysporum f. sp. lycopersici 1322. The inhibitory effect of oils showed dose-dependent activity on the tested fungus. Most active being the clove oil, exhibiting complete inhibition of mycelial growth and spore germination at 125 ppm with IC50 value of 18.2 and 0.3 ppm, respectively. Essential oils of lemongrass, mint and eucalyptus were inhibitory at relatively higher concentrations. The Minimum inhibitory concentration (MIC) of clove oil was 31.25 ppm by broth microdilution method. Thirty one different compounds of clove oil, constituting approximately ≥99% of the oil, were identified by gas chromatography–mass spectroscopy analysis. The major components were eugenol (75.41%), E-caryophyllene (15.11%), α-humulene (3.78%) and caryophyllene oxide (1.13%). Effect of clove oil on surface morphology of F. oxysporum f. sp. lycopersici 1322 was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM observation revealed shrivelled hyphae while AFM observation showed shrunken and disrupted spores in clove oil treated samples. In pots, 5% aqueous emulsion of clove oil controlled F. oxysporum f. sp. lycopersici 1322 infection on tomato plants. This study demonstrated clove oil as potent antifungal agent that could be used as biofungicide for the control of F. oxysporum f. sp. lycopersici in both preventive and therapeutic manner.
We seek to predict knee and ankle motion using wearable sensors. These predictions could serve as target trajectories for a lower limb prosthesis. In this manuscript, we investigate the use of ...egocentric vision for improving performance over kinematic wearable motion capture. We present an out-of-the-lab dataset of 23 healthy subjects navigating public classrooms, a large atrium, and stairs for a total of almost 12 hours of recording. The prediction task is difficult because the movements include avoiding obstacles, other people, idiosyncratic movements such as traversing doors, and individual choices in selecting the future path. We demonstrate that using vision improves the quality of the predicted knee and ankle trajectories, especially in congested spaces and when the visual environment provides information that does not appear simply in the movements of the body. Overall, including vision results in 7.9% and 7.0% improvement in root mean squared error of knee and ankle angle predictions respectively. The improvement in Pearson Correlation Coefficient for knee and ankle predictions is 1.5% and 12.3% respectively. We discuss particular moments where vision greatly improved, or failed to improve, the prediction performance. We also find that the benefits of vision can be enhanced with more data. Lastly, we discuss challenges of continuous estimation of gait in natural, out-of-the-lab datasets.
Rich variations in gait are generated according to several attributes of the individual and environment, such as age, athleticism, terrain, speed, personal "style", mood, etc. The effects of these ...attributes can be hard to quantify explicitly, but relatively straightforward to sample. We seek to generate gait that expresses these attributes, creating synthetic gait samples that exemplify a custom mix of attributes. This is difficult to perform manually, and generally restricted to simple, human-interpretable and handcrafted rules. In this manuscript, we present neural network architectures to learn representations of hard to quantify attributes from data, and generate gait trajectories by composing multiple desirable attributes. We demonstrate this method for the two most commonly desired attribute classes: individual style and walking speed. We show that two methods, cost function design and latent space regularization, can be used individually or combined. We also show two uses of machine learning classifiers that recognize individuals and speeds. Firstly, they can be used as quantitative measures of success; if a synthetic gait fools a classifier, then it is considered to be a good example of that class. Secondly, we show that classifiers can be used in the latent space regularizations and cost functions to improve training beyond a typical squared-error cost.
Abstract
The fabrication of nanomaterials from the top-down gives precise structures but it is costly, whereas bottom-up assembly methods are found by trial and error. Nature evolves materials ...discovery by refining and transmitting the blueprints using DNA mutations autonomously. Genetically inspired optimisation has been used in a range of applications, from catalysis to light emitting materials, but these are not autonomous, and do not use physical mutations. Here we present an autonomously driven materials-evolution robotic platform that can reliably optimise the conditions to produce gold-nanoparticles over many cycles, discovering new synthetic conditions for known nanoparticle shapes using the opto-electronic properties as a driver. Not only can we reliably discover a method, encoded digitally to synthesise these materials, we can seed in materials from preceding generations to engineer more sophisticated architectures. Over three independent cycles of evolution we show our autonomous system can produce spherical nanoparticles, rods, and finally octahedral nanoparticles by using our optimized rods as seeds.
Capsicum annuum L. production is impeded by various biotic factors, including fungal diseases caused by Colletotrichum capsici, Pythium aphanidermatum, and Fusarium oxysporum. Various plant extracts ...and essential oils are increasingly used to control different plant diseases. In this study, licorice (Glycyrrhiza glabra) cold water extract (LAE) and thyme (Thymus vulgaris) essential oil (TO) were found to be highly effective against the C. annuum pathogens. LAE at 200 mg ml−1 demonstrated the maximum antifungal activity of 89.9% against P. aphanidermatum, whereas TO at 0.25 mg ml−1 showed 100% inhibition of C. capsici. However, when used in combination, much lower doses of these plant protectants (100 mg ml−1 LAE and 0.125 mg ml−1 TO) exhibited a synergistic effect in controlling the fungal pathogens. Metabolite profiling using gas chromatography-mass spectrometry and high resolution-liquid chromatography-mass spectrophotometry analysis showed the presence of several bioactive compounds. Enhanced cellular components leakage revealed damage to the fungal cell wall and membrane due to and LAE treatment, which can be attributed to the TO lipophilicity and triterpenoid saponins of LAE. TO and LAE treatments also caused a reduction in ergosterol biosynthesis might be due to the presence of thymol and sterol components in the botanicals. Although the aqueous extracts have a low preparation cost, their uses are limited by modest shelf life and lacklustre antifungal effect. We have shown that these limitations can be bypassed by combining oil (TO) with the aqueous extract (LAE). This study further opens the avenues for utilizing these botanicals against other fungal phytopathogens.
•TO and LAE showed remarkable inhibitory activity against the chilli phytopathogens.•TO and LAE were observed to be damaging fungal cell wall and membrane.•No phytotoxicity was observed against the chilli by TO and LAE.•Combining TO with LAE resulted in synergistic antifungal effects.
Calocybe indica was cultivated on wheat straw enriched with various concentrations of sodium selenite (Na2SeO3), (2.5–40 μg/ml). The content of selenium (Se) in fruit bodies increased linearly by ...increasing the amount of Na2SeO3, although the biomass yield inhibited above 5 μg/ml. The fruit bodies accumulated inorganic Se into organic forms by integrating the Se into proteins (56%–68%), polysaccharides (22%–29%), and nucleic acids (1.4%–2.7%). Maximum protein content (25.31 g/100 g) was observed in fruit bodies harvested from the substrate enriched with 10 μg/ml Se. Amino acid profiling revealed the highest value of glutamic acid (4.73 g/100 g), followed by aspartic acid (1.80 g/100 g), and glycine (1.61 g/100 g) at 10 μg/ml. The Se enrichment also enhanced the total phenol, free radical 2,2-dipheynl-1-picrylhydrazyl (DPPH) scavenging activity and ferric reducing power (FRAP) of methanolic extracts of fruiting bodies to almost double of their contents. The principle component analysis (PCA) illustrated close correlations amongst the biomass yield, polyphenols, and antioxidant activities at 5 μg/ml concentrations of the Se.
•Edible mushroom Calocybe indica revealed a potential to bioaccumulate selenium.•Major portions of accumulated selenium were found to be associated with proteins.•Se-enriched C. indica fruiting bodies contained high protein and amino acid contents with very good antioxidant properties.•PCA illustrated the correlations amongst the contents of Se dosage, yield, proteins, phenols and antioxidant properties.
•Use of synergist clove and lemongrass oil in a single nanoemulsion.•Strong and rapid antifungal activity of nanoemulsion against Fusarium oxysporum f.sp. lycopersici.•Microscopic and spectrometric ...observations confirmed the membrane disruptive action of nanoformulation.•The proof-of-concept of the novel nanoemulsion is supported by in planta assays.
Essential oils play pivotal role in sustainably controlling plant pests and diseases. In this study, a synergistic oil-in-water nanoemulsion containing clove (CO) and lemongrass oil (LGO) was developed and explored its potential as antifungal agents against Fusarium oxysporum f.sp. lycopersici (FOL). After initial confirmation of synergism between CO-LGO, a nanoemulsion was formulated using non-ionic surfactants through low-energy emulsification method. The nanoemulsion showed Z-average diameter of 76.73 nm having spherical shaped droplet structure as confirmed by TEM imaging. Minimum inhibitory concentration (MIC) of the optimized nanoemulsion was 4000 mg/l against FOL with the logistic kinetic model demonstrating its notably rapid fungicidal effect. The nanoemulsion disrupted the membrane integrity of FOL as consistently evidenced by sodium dodecyl sulfate polyacrylamide gel electrophoresis, scanning electron and atomic force microscopy. During in planta assay, nanoformulation applied as a soil amendment at MIC reduced the severity of tomato Fusarium wilt incidence up to 70.6% compared with untreated control. The nanoemulsion applied on seedlings and seeds also significantly controlled the wilt disease in tomato without showing any sign of phytotoxicity.
Energy demand is increasing continuously due to the progress of industrialization, the vehicular population of the world, and modernization in lifestyle. In the present study, Chlorella minutissima ...microalgae were cultured in a 1500 L raceway open pond using commercial fertilizer under semi-continuous mode. About 19.98 wt % lipid was extracted by the soxhlet extraction method from this microalgae biomass. To optimize the input reaction parameters (temperature, lipid to methanol ratio, microwave power, and reaction time) for improving transesterification yield, Response Surface Methodology (RSM) was employed. The output responses of the experiments were biodiesel yield along with density, kinematic viscosity, calorific value, cold flow properties, and oxidation stability. To validate the model, confirmation trials were carried out. All the fuel properties were found to be satisfying ASTM D6751 and EN 14214 standard specifications except for oxidation stability at 3.0 h. The oxidation stability was further improved by using appropriate antioxidants and improved up to 10.5 h with the addition of 1000 ppm propyl gallate.
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•Chlorella minutissima cultivated in a 1500 L open raceway pond using commercial fertilizer.•Microwave-assisted transesterification of Chlorella minutissima lipids into methyl ester was explored.•Response surface methodology employed to optimize the biodiesel yield and fuel properties.•90.21% biodiesel yield observed at 63.93 °C, 10.5:1 methanol to lipid ratio, 700 W microwave irradiations and, 6.0 min reaction time.•Oxidation stability of CM biodiesel improved 3.75 times using 1000 ppm propyl gallate.
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