4,084 research outputs found
Study of K-Nearest Neighbour classification performance on fatigue and non-fatigue EMG signal features
© 2020, Science and Information Organization. For our body to move, the muscle must activate by relaxing and contracting. Muscle activation produces bio-electric signals that can be detected using Electromyography or EMG. The signal produced by the muscle is affected by the type of contraction done by the muscle. The eccentric contraction generating different EMG signals from concentric contraction. EMG signal contains multiple features. These features can be extracted using MATLAB software. This paper focuses on the bicep brachii and brachioradialis in the upper arm and forearm, respectively. The EMG signals are extracted using surface EMG whereby electrical pads are placed onto the surface of the muscle. Features can then be extracted from the EMG signal. This paper will focus on the MAV, VAR, and RMS features of the EMG signal. The features are then classified into eccentric, concentric or isometric contraction. The performance of the K-Nearest Neighbour (KNN) classifier is inconsistent due to the EMG data variabilities. The accuracy varies from one data set to another. However, it is concluded that non-fatigue signal classification accuracy is higher than fatigue signal classification accuracy
Public goods and decay in networks
We propose a simple behavioral model to analyze situations where (1) a group of agents repeatedly plays a public goods game within a network structure and (2) each agent only observes the past behavior of her neighbors, but is affected by the decisions of the whole group. The model assumes that agents are imperfect conditional cooperators, that they infer unobserved contributions assuming imperfect conditional cooperation by others, and that they have some degree of bounded rationality. We show that our model approximates quite accurately regularities derived from public goods game experiments
Scalable Production of Ambient Stable Hybrid Bismuth-based Materials: AACVD of Phenethylammonium Bismuth Iodide Films
Large homogeneous and adherent coatings of phenethylammonium bismuth iodide were produced using the cost-effective and scalable aerosol-assisted chemical vapour deposition (AACVD) methodology. The film morphology was found to depend on the deposition conditions and substrates, resulting in different optical properties to those reported from their spin-coated counterparts. Optoelectronic characterization revealed band bending effects occurring between the hybrid material and semiconducting substrates (TiO2 and FTO) due to heterojunction formation, and the optical bandgap of the hybrid material was calculated from UV-visible and PL spectrometry to be 2.05 eV. Maximum values for hydrophobicity and crystallographic preferential orientation were observed for films deposited on FTO/glass substrates, closely followed by values from films deposited on TiO2/glass substrates
Covering behavior of deep-water echinoids in Antarctica: possible response to predatory king crabs
This is the final version of the article. Available from Inter Research via the DOI in this record.Covering behavior refers to the propensity of echinoids (Echinoidea) to lift materials from the surrounding environment onto their aboral surfaces using their tube feet and spines. This behavior has been widely documented in regular echinoids from a variety of well-lit, shallow-marine habitats. Covering behavior in the deep sea, however, is rarely observed, and the functional significance of covering when it does occur remains speculative. During a photographic survey of the seafloor off Anvers Island and Marguerite Bay along the western Antarctic Peninsula, we imaged 11 benthic transects at depths ranging from 390 to 2100 m. We recorded the number of echinoid species, incidence of covering behavior, types of materials used for covering, potential predators of echinoids, and potential prey items for predators. The echinoid Sterechinus spp. was found at all depths, and the percentage of individuals exhibiting covering behavior increased with depth between 390 and 1500 m. There was a significant positive correlation between the incidence of covering behavior in Sterechinus spp. and the density of king crabs (Anomura: Lithodidae), crushing predators that may be expanding their bathymetric range up the Antarctic continental slope as a consequence of ongoing climatic warming. In contrast, covering behavior was not positively correlated with the densities of non-crab predators, the total densities of predators, or the availability of prey. Our results document rarely observed covering behavior in echinoids living in the deep sea and suggest that covering could be a behavioral response to predation pressure by king crabs.We thank the crew of the RV ‘Nathaniel B. Palmer’ during the NBP13-10 cruise for logistical help, as well as J. S. Anderson, A. Brown, C. Easson, D. Ellis, S. Thatje, and S. C. Vos. Thanks also to Paul Dayton as well as 2 anonymous reviewers who offered constructive comments and suggestions. Funding was provided by grants from the US National Science Foundation to R.B.A. (ANT- 1141877) and J.B.M. (ANT-1141896). This paper is contribution no. 160 from the Institute for Research on Global Climate Change at the Florida Institute of Technology
ZnO/BiOI heterojunction photoanodes with enhanced photoelectrochemical water oxidation activity
ZnO/BiOI heterojunction photoanode thin films were prepared by aerosol-assisted chemical vapour deposition, and the impact of growth temperature and film thickness on the water oxidation functionality was systematically investigated. A top ZnO layer with a thickness of 120 nm (deposited at 350 °C) and a 390 nm thick BiOI layer (deposited at 300 °C) were found to achieve the best photoelectrochemical performance of the heterojunction. The ZnO/BiOI heterojunction exhibited a significant increase in photoelectrochemical activity, with a photocurrent of 0.27 mA·cm−2 observed at 1.1 VRHE (350 nm, 2.58 mW·cm−2), which is ~ 2.2 times higher than that of single-layer ZnO and far higher than that of BiOI. Photoluminescence spectroscopy and transient absorption spectroscopy measurements showed that there was effective charge transfer across the heterojunction which spatially separated charge carriers and increased their lifetime and ability to drive photoelectrochemical water oxidation
Sparse Coding Predicts Optic Flow Specificities of Zebrafish Pretectal Neurons
Zebrafish pretectal neurons exhibit specificities for large-field optic flow
patterns associated with rotatory or translatory body motion. We investigate
the hypothesis that these specificities reflect the input statistics of natural
optic flow. Realistic motion sequences were generated using computer graphics
simulating self-motion in an underwater scene. Local retinal motion was
estimated with a motion detector and encoded in four populations of
directionally tuned retinal ganglion cells, represented as two signed input
variables. This activity was then used as input into one of two learning
networks: a sparse coding network (competitive learning) and backpropagation
network (supervised learning). Both simulations develop specificities for optic
flow which are comparable to those found in a neurophysiological study (Kubo et
al. 2014), and relative frequencies of the various neuronal responses are best
modeled by the sparse coding approach. We conclude that the optic flow neurons
in the zebrafish pretectum do reflect the optic flow statistics. The predicted
vectorial receptive fields show typical optic flow fields but also "Gabor" and
dipole-shaped patterns that likely reflect difference fields needed for
reconstruction by linear superposition.Comment: Published Conference Paper from ICANN 2018, Rhode
LARGE ROOT ANGLE1, encoding OsPIN2, is involved in root system architecture in rice
Root system architecture is very important for plant growth and crop yield. It is essential for nutrient and water uptake, anchoring, and mechanical support. Root growth angle (RGA) is a vital constituent of root system architecture and is used as a parameter for variety evaluation in plant breeding. However, little is known about the underlying molecular mechanisms that determine root growth angle in rice (Oryza sativa). In this study, a rice mutant large root angle1 (lra1) was isolated and shown to exhibit a large RGA and reduced sensitivity to gravity. Genome resequencing and complementation assays identified OsPIN2 as the gene responsible for the mutant phenotypes. OsPIN2 was mainly expressed in roots and the base of shoots, and showed polar localization in the plasma membrane of root epidermal and cortex cells. OsPIN2 was shown to play an important role in mediating root gravitropic responses in rice and was essential for plants to produce normal RGAs. Taken together, our findings suggest that OsPIN2 plays an important role in root gravitropic responses and determining the root system architecture in rice by affecting polar auxin transport in the root tip
Discovery of a recent, natural whale fall on the continental slope off Anvers Island, western Antarctic Peninsula
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Whale falls provide a substantial, nutrient-rich resource for species in areas of the ocean that may otherwise be largely devoid of food. We report the discovery of a natural whale fall at 1430 m depth in the cold waters of the continental slope off the western Antarctic Peninsula. This is the highest-latitude whale fall reported to date. The section of the carcass we observed—the tail fluke—was more complete than any previously reported natural whale fall from the deep sea and in the early stages of decomposition. We estimate the entire cetacean to measure 5–8 m in length. The flesh remained almost intact on the carcass but the skin was missing from the entire section except for the end of the fluke, clearly exposing blubber and soft tissue. The absence of skin indicates rapid and Homogeneous loss. The dominant macrofauna present were crustaceans, including most prominently the lithodid crab Paralomis birsteini, and zoarcid fish typical of the ‘mobile-scavenger’ successional stage. The density of mobile macrofauna was greatest on the carcass and declined to background levels within 100 m, indicating that they were attracted to the whale fall. This whale fall offers an important opportunity to examine the decomposition of a carcass under deep-sea conditions at polar latitudes.We are grateful to the captain and crew of the RV Nathaniel B. Palmer, and to the US Antarctic Support Contractor, Lockheed Martin, for their assistance at sea. We thank J.T. Eastman and two anonymous reviewers for helpful comments on the manuscript. Funding was provided by grants from the U.S. National Science Foundation: ANT-1141877 to R.B.A. and ANT-1141896 to J.B.M. This is contribution 122 from the Institute for Research on Global Climate Change at the Florida Institute of Technology
Towards Visual Foundational Models of Physical Scenes
We describe a first step towards learning general-purpose visual
representations of physical scenes using only image prediction as a training
criterion. To do so, we first define "physical scene" and show that, even
though different agents may maintain different representations of the same
scene, the underlying physical scene that can be inferred is unique. Then, we
show that NeRFs cannot represent the physical scene, as they lack extrapolation
mechanisms. Those, however, could be provided by Diffusion Models, at least in
theory. To test this hypothesis empirically, NeRFs can be combined with
Diffusion Models, a process we refer to as NeRF Diffusion, used as unsupervised
representations of the physical scene. Our analysis is limited to visual data,
without external grounding mechanisms that can be provided by independent
sensory modalities.Comment: TLDR: Physical scenes are equivalence classes of sufficient
statistics, and can be inferred uniquely by any agent measuring the same
finite data; We formalize and implement an approach to representation
learning that overturns "naive realism" in favor of an analytical approach of
Russell and Koenderink. NeRFs cannot capture the physical scenes, but
combined with Diffusion Models they ca
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