952 results match your criteria: "The University of Electro- Communications[Affiliation]"

Camera-based remote photoplethysmography (rPPG) is a low-cost and casual non-contact heart rate measurement method suitable for telemedicine. Several factors affect the accuracy of measuring the heart rate and heart rate variability (HRV) using rPPG despite HRV being an important indicator for healthcare monitoring. This study aimed to investigate the appropriate setup for precise HRV measurements using rPPG while considering the effects of possible factors including illumination, direction of the light, frame rate of the camera, and body motion.

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Exact Learning Augmented Naive Bayes Classifier.

Entropy (Basel)

December 2021

Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1, Chofugaoka, Chofu-shi, Tokyo 182-8585, Japan.

Earlier studies have shown that classification accuracies of Bayesian networks (BNs) obtained by maximizing the conditional log likelihood (CLL) of a class variable, given the feature variables, were higher than those obtained by maximizing the marginal likelihood (ML). However, differences between the performances of the two scores in the earlier studies may be attributed to the fact that they used approximate learning algorithms, not exact ones. This paper compares the classification accuracies of BNs with approximate learning using CLL to those with exact learning using ML.

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It has been well established in epidemiological studies and randomized controlled trials that habitual exercise is beneficial for brain health, such as cognition and mental health. Generally, it may be reasonable to say that the physiological benefits of acute exercise can prevent brain disorders in late life if such exercise is habitually/chronically conducted. However, the mechanisms of improvement in brain function via chronic exercise remain incompletely understood because such mechanisms are assumed to be multifactorial, such as the adaptation of repeated acute exercise.

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Characterization of Sustainable Robotic Materials and Finite Element Analysis of Soft Actuators Under Biodegradation.

Front Robot AI

November 2021

Department of Mechanical and Intelligent Systems Engineering, School of Informatics and Engineering, The University of Electro-Communications, Chofu, Japan.

Biodegradability is an important property for soft robots that makes them environmentally friendly. Many biodegradable materials have natural origins, and creating robots using these materials ensures sustainability. Hence, researchers have fabricated biodegradable soft actuators of various materials.

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Monolithic Stacked Dielectric Elastomer Actuators.

Front Robot AI

November 2021

Department of Mechanical and Intelligent Systems Engineering, School of Informatics and Engineering, The University of Electro-Communications, Chofu, Japan.

Dielectric elastomer actuators (DEAs) are a promising actuator technology for soft robotics. As a configuration of this technology, stacked DEAs afford a muscle-like contraction that is useful to build soft robotic systems. In stacked DEAs, dielectric and electrode layers are alternately stacked.

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Humans and animals learn the internal model of bodies and environments from their experience and stabilize posture against disturbances based on the predicted future states according to the internal model. We evaluated the mechanism of predictive control during standing, by using rats to construct a novel experimental system and comparing their behaviors with a mathematical model. In the experiments, rats ( = 6) that were standing upright using their hindlimbs were given a sensory input of light, after a certain period, the floor under them tilted backward.

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A Synthetic Model for the Possible Fe(μ-O) Core of Methane Monooxygenase Intermediate Q Derived from a Structurally Characterized FeFe(μ-O) Complex.

Inorg Chem

January 2022

Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe, Kyoto 610-0321, Japan.

A bis(μ-oxo)diiron(IV,IV) complex as a model for intermediate Q in the methane monooxygenase reaction cycle has been prepared. The precursor complex with a [FeFe(μ-O)] core was fully characterized by X-ray crystallography and other spectroscopic analyses and was converted to the [Fe(μ-O)] complex via electrochemical oxidation at 1000 mV (vs Ag/Ag) in acetone at 193 K. The UV-vis spectral features, Mössbauer parameters (Δ = 2.

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Article Synopsis
  • Noise-free ultrasound images are crucial for monitoring organs during regional therapy, but acoustic shadowing from bones can lead to missing information.
  • The study introduced a method utilizing a convolutional neural network for classifying acoustic shadow presence and created a composite shadow-free image by superimposing suitable images from a time-series database.
  • Results showed improved accuracy for kidney tracking, with enhanced image correlations, although further validation on real organs is needed.
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Superconducting-like Heat Current: Effective Cancellation of Current-Dissipation Trade-Off by Quantum Coherence.

Phys Rev Lett

November 2021

Theoretical Physics Laboratory, RIKEN Cluster for Pioneering Reserach, Wako-shi, Saitama 351-0198, Japan.

Quantum coherence is a useful resource for increasing the speed and decreasing the irreversibility of quantum dynamics. Because of this feature, coherence is used to enhance the performance of various quantum information processing devices beyond the limitations set by classical mechanics. However, when we consider thermodynamic processes, such as energy conversion in nanoscale devices, it is still unclear whether coherence provides similar advantages.

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Background: Electrical muscle stimulation (EMS) induces involuntary muscle contraction. Several studies have suggested that EMS has the potential to be an alternative method of voluntary exercise; however, its effects on cerebral blood flow (CBF) when applied to large lower limb muscles are poorly understood. Thus, the purpose of this study was to examine the effects of EMS on CBF, focusing on whether the effects differ between the internal carotid (ICA) and vertebral (VA) arteries.

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Bismuth Vacancy-Induced Efficient CO Photoreduction in BiOCl Directly from Natural Air: A Progressive Step toward Photosynthesis in Nature.

Nano Lett

December 2021

Key Laboratory of Modern Acoustics (MOE), Institute of Acoustics, School of Physics, Eco-materials and Renewable Energy Research Center (ERERC), National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory for Nano Technology, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu 210093, P. R. China.

Photocatalytic CO conversion into carbonaceous fuels through artificial photosynthesis is beneficial to global warming mitigation and renewable resource generation. However, a high cost is always required by special CO-capturing devices for efficient artificial photosynthesis. For achieving highly efficient photocatalytic CO reduction (PCR) directly from natural air, we report rose-like BiOCl that is rich in Bi vacancies (V) assembled by nanosheets with almost fully exposed active {001} facets.

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Design and Implementation of Symmetric Legged Robot for Highly Dynamic Jumping and Impact Mitigation.

Sensors (Basel)

October 2021

Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China.

Aiming at highly dynamic locomotion and impact mitigation, this paper proposes the design and implementation of a symmetric legged robot. Based on the analysis of the three-leg topology in terms of force sensitivity, force production, and impact mitigation, the symmetric leg was designed and equipped with a high torque density actuator, which was assembled by a custom motor and two-stage planetary. Under the kinematic and dynamic constraints of the robot system, a nonlinear optimization for high jumping and impact mitigation is proposed with consideration of the peak impact force at landing.

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The major goals of texture research in computer vision are to understand, model, and process texture and ultimately simulate human visual information processing using computer technologies. The field of computer vision has witnessed remarkable advancements in material recognition using deep convolutional neural networks (DCNNs), which have enabled various computer vision applications, such as self-driving cars, facial and gesture recognition, and automatic number plate recognition. However, for computer vision to "express" texture like human beings is still difficult because texture description has no correct or incorrect answer and is ambiguous.

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Bio-Inspired Take-Off Maneuver and Control in Vertical Jumping for Quadruped Robot with Manipulator.

Micromachines (Basel)

September 2021

Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China.

The jumping motion of legged robots is an effective way to overcome obstacles in the rugged microgravity planetary exploration environment. At the same time, a quadruped robot with a manipulator can achieve operational tasks during movement, which is more practical. However, the additional manipulator will restrict the jumping ability of the quadruped robot due to the increase in the weight of the system, and more active degrees of freedom will increase the control complexity.

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Article Synopsis
  • Impairment of inferior olivary neurons (IONs) impacts whole-body movements, leading to abnormal gait and posture in rats.
  • A study analyzed the postural movements of rats with pharmacological ION lesions, revealing changes in the control of body movements rather than just feedback loss.
  • Mathematical modeling showed that ION lesions resulted in increased linear control and decreased differential/nonlinear control, suggesting a disorder in the internal control model may explain these changes.
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Single-Atom High-Temperature Catalysis on a RhO Cluster for Production of Syngas from Methane.

J Am Chem Soc

October 2021

Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66049, United States.

Single-atom catalysts are a relatively new type of catalyst active for numerous reactions but mainly for chemical transformations performed at low or intermediate temperatures. Here we report that singly dispersed RhO clusters on TiO can catalyze the partial oxidation of methane (POM) at high temperatures with a selectivity of 97% for producing syngas (CO + H) and high activity with a long catalytic durability at 650 °C. The long durability results from the substitution of a Ti atom of the TiO surface lattice by Rh, which forms a singly dispersed Rh atom coordinating with five oxygen atoms (RhO) and an undercoordinated environment but with nearly saturated bonding with oxygen atoms.

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Myoelectric prosthesis has become an important aid to disabled people. Although it can help people to recover to a nearly normal life, whether they can adapt to severe working conditions is a subject that is yet to be studied. Generally speaking, the working environment is dominated by vibration.

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Purpose: Diagnosis of liver fibrosis is important for establishing treatment and assessing the risk of carcinogenesis. Ultrasound imaging is an excellent diagnostic method as a screening test in terms of non-invasiveness and simplicity. The purpose of this study was to automatically diagnose liver fibrosis using ultrasound images to reduce the burden on physicians.

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In this work, we represent the lightning initiation scenario as a sequence of two transitions of discharge activity to progressively larger spatial scales: the first one is from small-scale avalanches to intermediate-scale streamers; and the second one is from streamers to the lightning seed. We postulate the existence of ion production centers in the cloud, whose occurrence is caused by electric field bursts accompanying hydrometeor collisions (or near collisions) in the turbulent thundercloud environment. When a new ion production center is created inside (fully or partially) the residual ion spot left behind by a previously established center, there is a cumulative effect in the increasing of ion concentration.

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Interspecies variation of larval locomotion kinematics in the genus Drosophila and its relation to habitat temperature.

BMC Biol

September 2021

Department of Complexity Science and Engineering, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan.

Background: Speed and trajectory of locomotion are the characteristic traits of individual species. Locomotion kinematics may have been shaped during evolution towards increased survival in the habitats of each species. Although kinematics of locomotion is thought to be influenced by habitats, the quantitative relation between the kinematics and environmental factors has not been fully revealed.

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Highly efficient persistent (lifetime > 0.1 s) room-temperature phosphorescence (RTP) chromophores are important for futuristic high-resolution afterglow imaging for state-of-the-art security, analytical, and bioimaging applications. Suppression of the radiationless transition from the lowest triplet excited state (T) of the chromophores is a critical factor to access the high RTP yield and RTP lifetime for desirable RTP.

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Article Synopsis
  • The study focuses on developing an efficient, low-cost real-time facial recognition system using advanced deep learning algorithms like FaceNet in combination with traditional classifiers such as SVM, KNN, and RF.
  • For face detection, the YOLO-Face method, which operates at high speed, is utilized, achieving over 89.6% accuracy even under challenging conditions like partial occlusion and varied poses.
  • The combined system demonstrates impressive recognition capabilities, with FaceNet+SVM reaching 99.7% accuracy and the overall system providing a 99.1% accuracy rate with a fast runtime of 49 ms.
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The steady-state visual evoked potential (SSVEP), which is a kind of event-related potential in electroencephalograms (EEGs), has been applied to brain-computer interfaces (BCIs). SSVEP-based BCIs currently perform the best in terms of information transfer rate (ITR) among various BCI implementation methods. Canonical component analysis (CCA) or spectrum estimation, such as the Fourier transform, and their extensions have been used to extract features of SSVEPs.

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Biometric Identification Systems with Noisy Enrollment for Gaussian Sources and Channels.

Entropy (Basel)

August 2021

Department of Computer and Network Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Tokyo 182-8585, Japan.

In the present paper, we investigate the fundamental trade-off of identification, secret-key, storage, and privacy-leakage rates in biometric identification systems for remote or hidden Gaussian sources. We use a technique of converting the system to one where the data flow is in one-way direction to derive the capacity region of these rates. Also, we provide numerical calculations of three different examples for the system.

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Hollow InVO Nanocuboid Assemblies toward Promoting Photocatalytic N Conversion Performance.

Adv Mater

October 2021

Key Laboratory of Modern Acoustics (MOE), Institute of Acoustics, Jiangsu Key Laboratory for Nano Technology, Ecomaterials and Renewable Energy Research Center (ERERC), School of Physics, National Laboratory of Solid State Microstructures, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu, 210093, P. R. China.

The unique InVO mesocrystal superstructure, particularly with cubical skeleton and hollow interior, which consists of numerous nanocube building blocks, closely stacking by stacking, aligning by aligning, and sharing the same crystallographic orientations, is successfully fabricated. The synergy of a reaction-limited aggregation and an Ostwald ripening process is reasonably proposed for the growth of this unique superstructure. Both single-particle surface photovoltage and confocal fluorescence spectroscopy measurements demonstrate that the long-range ordered mesocrystal superstructures can significantly retard the recombination of electron-hole pairs through the creation of a new pathway for anisotropic electron flow along the inter-nanocubes.

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